U.S. patent application number 16/075159 was filed with the patent office on 2019-02-07 for digitally-controlled three-dimensional printing using ring-opening metathesis polymerization.
The applicant listed for this patent is Stratasys Ltd.. Invention is credited to Lev KUNO, Eynat MATZNER, Asher RAZLAN, Yuval VIDAVSKY, Ira YUDOVIN-FARBER.
Application Number | 20190039321 16/075159 |
Document ID | / |
Family ID | 58094475 |
Filed Date | 2019-02-07 |
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United States Patent
Application |
20190039321 |
Kind Code |
A1 |
MATZNER; Eynat ; et
al. |
February 7, 2019 |
DIGITALLY-CONTROLLED THREE-DIMENSIONAL PRINTING USING RING-OPENING
METATHESIS POLYMERIZATION
Abstract
Provided are methods of fabricating an object, effected by
jetting two or more different modeling material formulation, each
containing a different material or mixture of materials, and at
least one containing an unsaturated cyclic monomer that is
polymerizable by ROMP, which, when contacted on a receiving medium,
undergo a reaction therebetween to form a cured modeling material.
The chemical composition of the formed cured material is dictated
by a ratio of the number of voxels of each modeling material
formulation in a voxel block. Systems for executing the methods,
and printed objects obtained thereby are also provided.
Inventors: |
MATZNER; Eynat; (Doar-Na
haMovil, IL) ; YUDOVIN-FARBER; Ira; (Rehovot, IL)
; VIDAVSKY; Yuval; (Moshav Sitriya, IL) ; RAZLAN;
Asher; (Rehovot, IL) ; KUNO; Lev;
(Tzur-Hadassah, IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Stratasys Ltd. |
Rehovot |
|
IL |
|
|
Family ID: |
58094475 |
Appl. No.: |
16/075159 |
Filed: |
February 5, 2017 |
PCT Filed: |
February 5, 2017 |
PCT NO: |
PCT/IL2017/050140 |
371 Date: |
August 3, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62327474 |
Apr 26, 2016 |
|
|
|
62291625 |
Feb 5, 2016 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B29C 64/209 20170801;
B33Y 70/00 20141201; C08K 3/013 20180101; B33Y 10/00 20141201; B29C
64/112 20170801; B29C 64/393 20170801; C09D 11/102 20130101; B33Y
50/02 20141201; C08G 2261/418 20130101; C09D 11/101 20130101; B33Y
30/00 20141201; C09D 11/38 20130101; C08G 61/08 20130101 |
International
Class: |
B29C 64/393 20060101
B29C064/393; C08G 61/08 20060101 C08G061/08; B29C 64/112 20060101
B29C064/112; B29C 64/209 20060101 B29C064/209; C08K 3/013 20060101
C08K003/013 |
Claims
1-49. (canceled)
50. A method of fabricating an object, by three-dimensional inkjet
printing, the method comprising: receiving three-dimensional
printing data corresponding to the shape of the object; selecting a
ratio between a first modeling material formulation and a second
modeling material formulation, wherein said first modeling material
formulation comprises a first material, said first material being a
first ROMP monomer and said second modeling material formulation
comprises a second material that reacts with said ROMP monomer so
as to form a cured model material when exposed to a curing
condition, and wherein at least one of said first and second
modeling material formulations further comprises a catalyst for
initiating ROMP of said monomer; dispensing droplets of said first
and said second modeling material formulations in layers, on a
receiving medium, according to said printing data; wherein for at
least one region of the object, said dispensing of said droplets is
selected to form voxel blocks, wherein, for each block, a ratio
between a number of voxels of said first modeling material
formulation in said block and a number of voxels of said second
modeling material formulation in said block corresponds to said
selected ratio.
51. The method of claim 50, wherein each of said voxel blocks
comprises from 2 to 20 voxels.
52. The method of claim 50, wherein at least said first modeling
material formulation is characterized by a viscosity of no more
than 35 centipoises at a temperature of said inkjet printing head
during said dispensing.
53. The method of claim 50, further comprising exposing the
dispensed layers to said curing condition.
54. The method of claim 50, wherein said second material is
selected capable of modifying a chemical, physical and/or
mechanical property of a modeling material formed of said ROMP
monomer, upon reacting with said ROMP monomer and exposure to said
curing condition, and wherein a degree of said modifying is
determined by selecting said ratio.
55. The method of claim 50, wherein said second material comprises
a moiety which is such that when forming a part of a modeling
material formed of said ROMP monomer, a chemical, physical and/or
mechanical property of said modeling material is modified.
56. The method of claim 50, wherein said second material is an
elastomeric material.
57. The method of claim 56, wherein said elastomeric material is
characterized by at least one of: a molecular weight lower than
50,000, or lower than 40,000, or, preferably, lower than 30,000, or
lower than 20,000, or lower than 10,000 Daltons; non-reactivity
towards ROMP; dissolvability or dispersibilty in a modeling
material formulation containing same; and capability of forming a
multiphase structure when blended with said cured modeling
material.
58. The method of claim 50, wherein at least one of said first and
said second model formulations further comprises a second ROMP
monomer, said second ROMP monomer being different from said first
ROMP monomer.
59. The method of claim 58, wherein said second ROMP monomer is a
bi-functional or multi-functional ROMP monomer.
60. The method of claim 59, wherein said second ROMP monomer is
said second material.
61. The method of claim 50, wherein prior to exposing to said
curing condition said catalyst does not initiate ROMP of a ROMP
monomer.
62. The method of claim 61, wherein said first modeling formulation
further comprises said catalyst, and said catalyst is activatable
by said curing condition.
63. The method of claim 61, wherein said catalyst is activatable by
an activator, and at least one of said modeling material
formulations comprises said activator and is devoid of said
catalyst.
64. The method of claim 50, wherein at least one of said first and
second modeling material formulations further comprises at least
one non-ROMP material polymerizable or curable via a non-ROMP
reaction.
65. The method of claim 50, wherein said second material is a
non-ROMP material polymerizable or curable via a non-ROMP
reaction.
66. The method of claim 65, wherein said curing condition further
comprises a condition for inducing polymerization or curing of said
at least one non-ROMP material.
67. The method of claim 50, wherein a temperature of an inkjet
printing head for dispensing at least said first modeling material
formulation ranges from 25.degree. C. to 65.degree. C.
68. The method of claim 50, wherein said dispensing and/or said
exposing are performed under inert atmosphere.
69. A kit comprising at least two modeling material formulations
usable in a method of fabricating an object by three-dimensional
inkjet printing, said at least two modeling material formulations
being individually packaged within the kit, wherein said at least
two modeling material formulations comprise: a first modeling
material formulations comprising a first material, said first
material being a first ROMP monomer; and said second modeling
material formulation comprising a second material that reacts with
said ROMP monomer so as to form a cured model material when exposed
to a curing condition, said second material being selected capable
of modifying a chemical, physical and/or mechanical property of a
modeling material formed of said first ROMP monomer, upon reacting
with said first ROMP monomer and exposure to said curing condition,
at least one of said first and second modeling material
formulations further comprising a catalyst for initiating ROMP of
said monomer.
70. The kit of claim 69, wherein said second material comprises a
moiety which is such that when forming a part of a modeling
material formed of said first ROMP monomer, a chemical, physical
and/or mechanical property of said modeling material is modified.
Description
FIELD AND BACKGROUND OF THE INVENTION
[0001] The present invention, in some embodiments thereof, relates
to three-dimensional printing and, more particularly, but not
exclusively, to methods of performing three-dimensional inkjet
printing, employing ring-opening metathesis polymerization (ROMP),
and to objects obtained by these methods.
[0002] Three-dimensional (3D) inkjet printing is a known process
for building three dimensional objects by selectively jetting
chemical compositions, for example, polymerizable compositions, via
ink-jet printing head nozzles, onto a printing tray in consecutive
layers, according to pre-determined image data. 3D inkjet printing
is performed by a layer by layer inkjet deposition of chemical
compositions. Thus, a chemical composition is dispensed in droplets
from a dispensing head having a set of nozzles to form layers on a
receiving medium. The layers may then be cured or solidified using
a suitable methodology, to form solidified or partially solidified
layers of the building material.
[0003] The chemical compositions used for forming the building
material may be initially liquid and subsequently hardened (cured
or solidified) to form the required layer shape. The hardening may
be effected, for example, by exposing the building material to a
curing energy such as thermal energy (e.g., by heating the building
material) or to irradiation (e.g., UV or other photo-irradiation),
or may be activated chemically, for example, by acid or base
activation.
[0004] The chemical (e.g., polymerizable) compositions utilized in
3D inkjet printing processes are therefore selected so as to meet
the process requirements, namely, exhibiting a suitable viscosity
during jetting (thus being non-curable under jetting conditions)
and rapid curing or solidification, typically upon exposure to a
stimulus on the receiving medium. The building materials may
include modeling materials and support materials, which form the
object and optionally the temporary support constructions
supporting the object as it is being built, respectively. The
modeling material (which may include one or more material(s)) is
deposited to produce the desired object/s and the support material
(which may include one or more material(s)) is used, with or
without modeling material elements, to provide support structures
for specific areas of the object during building and assure
adequate vertical placement of subsequent object layers, e.g., in
cases where objects include overhanging features or shapes such as
curved geometries, negative angles, voids, and so on.
[0005] Both the modeling and support materials are preferably
liquid at the working temperature at which they are dispensed, and
subsequently hardened, upon exposure to a condition that affects
curing of the materials, to form the required layer shape. After
printing completion, support structures, if present, are removed to
reveal the final shape of the fabricated 3D object.
[0006] In order to be compatible with most of the
commercially-available printing heads utilized in a 3D inkjet
printing system, the uncured building material should feature the
following characteristics: a relatively low viscosity (e.g.,
Brookfield Viscosity of up to 35 cps, preferably from 8 to 25 cps)
at the working (e.g., jetting) temperature; Surface tension of from
about 10 to about 50 Dyne/cm; and a Newtonian liquid behavior and
high reactivity to a selected curing energy, to enable immediate
solidification of the jetted layer upon exposure to a curing
energy).
[0007] The cured modeling material which forms the final object
should preferably exhibit heat deflection temperature (HDT) which
is higher than room temperature, in order to assure its usability.
Typically, the cured modeling material should exhibit HDT of at
least 35.degree. C. For an object to be stable at variable
conditions, a higher HDT is desirable. In most cases, it is also
desirable that the object exhibits relatively high Izod Notched
impact, e.g., higher than 50 or higher than 60 J/m.
[0008] Until today, most 3D inkjet methodologies have utilized
photopolymerizable materials, and photo-induced curing, typically
UV curing, thus narrowing the choice of materials and chemical
reactions that can be utilized in this technology. Exemplary
photopolymerizable building materials that are currently used in,
for example, a "PolyJet" technology (Stratasys Ltd., Israel), are
acrylic based materials.
[0009] International Patent Application Publication No. WO
2013/128452, by the present Assignee, discloses a multi-material
approach which involves separate jetting of two components of a
cationic polymerizable system and/or a radical polymerizable
system, which intermix on the printing tray, leading to a
polymerization reaction similar to pre-mixing of the two components
before jetting, while preventing their early polymerization on the
inkjet head nozzle plate.
[0010] Ring-opening metathesis polymerization (ROMP) is a type of
olefin metathesis chain-growth polymerization. The driving force of
the reaction is the relief of strained cyclic structures, typically
cyclic olefins (e.g., norbornenes or cyclopentenes) or dienes
(e.g., cyclopentadiene-based compounds). The polymerization
reaction typically occurs in the presence of organometallic
catalysts, and the ROMP catalytic cycle involves formation of
metal-carbene species, which reacts with the double bond in the
cyclic structure to thereby form a highly strained
metallacyclobutane intermediate. The ring then opens, giving a
linear chain double bonded to the metal and terminated with a
double bond. The as formed metal-carbene species then reacts with
the double bond on another cyclic monomer, and so forth.
[0011] During recent decades ROMP evolved as a powerful
polymerization tool especially due to the development of
well-defined transition metal complexes as catalysts. Ruthenium,
molybdenum and osmium carbene complexes useful as catalysts of ROMP
reactions are described, for example, in U.S. Pat. Nos. 5,312,940,
5,342,909, 5,728,917, 5,710,298, 5,831,108, and 6,001,909; and PCT
International Patent Applications having Publication Nos. WO
97/20865, WO 97/29135 and WO 99/51344.
[0012] The use of ROMP reactions in reaction injection molding
(RIM) has been described, for example, in U.S. Patent Application
Publication Nos. 2011/0171147, 2005/0691432, U.S. Pat. No.
8,487,046, EP Patent Application Publication No. 2452958, and EP
Patent No. 2280017. One of the ROMP materials used in ROMP-based
RIM is dicyclopentadiene (DCPD).
[0013] Poly-DCPD-based materials exhibit good mechanical properties
and combine both good toughness and high thermal resistance. For
example, polymeric materials based on DCPD were used to produce
Telene 1810, which features a viscosity of about 200 cps at room
temperature, HDT of 120.degree. C. and impact of 300 J/m; and
Metton M15XX, which features a viscosity of 300 cps at room
temperature, Tg of 130.degree. C. and impact of 460 J/m [see, for
example,
www(dot)metton(dot)com/index(dot)php/metton-lmr/benefits].
[0014] Additional background art includes WO 2013/128452; Adv.
Funct. Mater. 2008, 18, 44-52; Adv. Mater. 2005, 17, 39-42; and
Pastine, S. J.; Okawa, D.; Zettl, A.; Frechet, J. M. J. J. Am.
Chem. Soc. 2009, 131, 13586-13587; Vidaysky and Lemcoff, Beilstein
J. Org. Chem. 2010, 6, 1106-1119; Ben-Asuly et al., Organometallics
2009, 28, 4652-4655; Piermattei et al., Nature Chemistry, DOI:
10.1038/NCHEM.167; Szadkowska et al., Organometallics 2010, 29,
117-124; Diesendruck, C. E.; Vidavsky, Y.; Ben-Asuly, A.; Lemcoff,
N. G., J. Polym. Sci., Part A: Polym. Chem. 2009, 47, 4209-4213;
Wang et al., Angew. Chem. Int. Ed. 2008, 47, 3267-3270; U.S. Patent
Application Publication No. 2009-0156766; WO 2014/144634; EP Patent
No. 1757613; U.S. Pat. No. 8,519,069; and PCT International
Application No. PCT/IL2015/051038 published as WO 2016/063282.
SUMMARY OF THE INVENTION
[0015] The present inventors have devised and successfully
practiced a methodology for inkjet printing of objects made of
chemical compositions which form a cured building material (e.g., a
cured modeling material) upon exposure to a curing condition, while
digitally controlling the properties of the obtained building
material, at a voxel level. This methodology is based on dual
jetting of two or more different formulations (e.g., model
formulations), each containing a different material or mixture of
materials, which, when contacted, undergo a chemical reaction
therebetween to form the cured building (e.g., modeling) material.
The chemical composition of the formed cured building (e.g.,
modeling) material is dictated by the number of voxels of each
formulation in a voxel block. This methodology allows a production
of, for example, printed objects which feature different chemical
compositions and hence different properties for different voxel
blocks, as desired.
[0016] According to the present embodiments, the methodology
described herein is utilized for printing objects made of, or
comprising, cured materials obtained while employing Ring Opening
Metathesis Polymerization (ROMP) systems and ROMP-based
methodologies, while controlling the properties of the objects at
the voxel level. The control of these properties is made by dual
jetting of one formulation (e.g., a first model formulation) that
comprises a ROMP monomer, and one formulation (e.g., a second model
formulation) that comprises a second material that modifies a
property of a polymeric material formed of the ROMP monomer while
controlling the ratio of the formulations at the voxel level, and
subjecting the layers formed of the jetted formulations to a curing
condition that effects ROMP.
[0017] According to an aspect of some embodiments of the present
invention there is provided a method of fabricating an object (a
three-dimensional object), the method comprising:
[0018] receiving three-dimensional printing data corresponding to
the shape of the object;
[0019] selecting a ratio between a first modeling material
formulation and a second modeling material formulation, wherein the
first modeling material formulation comprises a first material, the
first material being a first ROMP monomer and the second modeling
material formulation comprises a second material that reacts with
the ROMP monomer so as to form a cured model material when exposed
to a curing condition, and wherein at least one of the first and
second modeling material formulations further comprises a catalyst
for initiating ROMP of the monomer;
[0020] dispensing droplets of the first and the second modeling
material formulations in layers, on a receiving medium, using at
least two different inkjet printing heads, according to the
printing data;
[0021] wherein for at least one region of the object, the
dispensing of the droplets is selected to form voxel blocks,
wherein, for each block, a ratio between a number of voxels of the
first modeling material formulation in the block and a number of
voxels of the second modeling material formulation in the block
corresponds to the selected ratio.
[0022] According to some of any of the embodiments of the present
invention, each of the voxel blocks comprises from 2 to 20
voxels.
[0023] According to some of any of the embodiments of the present
invention, selecting the ratio is performed for at least two
different layers.
[0024] According to some of any of the embodiments of the present
invention, selecting the ratio is executed at least twice for at
least one of the layers.
[0025] According to some of any of the embodiments of the present
invention, at least the first modeling material formulation is
characterized by a viscosity of no more than 35 centipoises at a
temperature of the inkjet printing head during the dispensing.
[0026] According to some of any of the embodiments of the present
invention, the curing condition comprises a condition for inducing
initiation of ROMP of the monomer by the catalyst.
[0027] According to some of any of the embodiments of the present
invention, the method further comprises exposing the dispensed
layers to the curing condition.
[0028] According to some of any of the embodiments of the present
invention, the second material is selected capable of modifying a
chemical, physical and/or mechanical property of a (e.g., cured)
modeling material formed of the ROMP monomer, upon reacting with
the ROMP monomer and exposure to the curing condition, and wherein
a degree of the modifying is determined by selecting the ratio.
[0029] According to some of any of the embodiments of the present
invention, the second material comprises a moiety which is such
that when forming a part of a (e.g., cured) modeling material
formed of the ROMP monomer, a chemical, physical and/or mechanical
property of the (e.g., cured) modeling material is modified.
[0030] According to some of any of the embodiments of the present
invention, the second material comprises a toughening agent (e.g.,
an impact modifying agent or moiety), an elastomeric material or
moiety), and optically-active agent or moiety, a light-absorbing
agent or moiety, a hydrophobic material or moiety, a hydrophilic
material or moiety and/or a chemically-reactive material or
moiety.
[0031] According to some of any of the embodiments of the present
invention, at least one of the first and the second model
formulations further comprises a second ROMP monomer, the second
ROMP monomer being different from the first ROMP monomer.
[0032] According to some of any of the embodiments of the present
invention, the second ROMP monomer is a bi-functional or
multi-functional ROMP monomer. According to some of these
embodiments, the first ROMP monomer is a mono-functional ROMP
monomer.
[0033] According to some of any of the embodiments of the present
invention, the second ROMP monomer is the second material.
[0034] According to some of any of the embodiments of the present
invention, the second material is a non-curable material.
[0035] According to some of any of the embodiments of the present
invention, prior to exposing to the curing condition the catalyst
does not initiate ROMP of a ROMP monomer.
[0036] According to some of any of the embodiments of the present
invention, the first modeling formulation further comprises the
catalyst, and the catalyst is activatable by the curing
condition.
[0037] According to some of any of the embodiments of the present
invention, the catalyst is activatable by an activator, and at
least one of the modeling material formulations comprises the
activator and is devoid of the catalyst.
[0038] According to some of any of the embodiments of the present
invention, the first modeling material formulation comprises the
first ROMP monomer and the activator and the second modeling
material formulation comprises the catalyst.
[0039] According to some of any of the embodiments of the present
invention, the first modeling material formulation comprises the
first ROMP monomer and the catalyst and the second modeling
material formulation comprises the activator.
[0040] According to some of any of the embodiments of the present
invention, at least one of the first and second modeling material
formulations further comprises a ROMP inhibitor.
[0041] According to some of any of the embodiments of the present
invention, at least one of the first and second modeling material
formulations further comprises at least one non-ROMP material
polymerizable or curable via a non-ROMP reaction.
[0042] According to some of any of the embodiments of the present
invention, the second material is a non-ROMP material polymerizable
or curable via a non-ROMP reaction.
[0043] According to some of any of the embodiments of the present
invention, the curing condition further comprises a condition for
inducing polymerization or curing of the at least one non-ROMP
material.
[0044] According to some of any of the embodiments of the present
invention, the non-ROMP material comprises a monomer and/or an
oligomer polymerizable by free-radical polymerization, cationic
polymerization, anionic polymerization, or polycondensation.
[0045] According to some of any of the embodiments of the present
invention, the non-ROMP material is polymerizable or curable upon
exposure to irradiation (photopolymerizable).
[0046] According to some of any of the embodiments of the present
invention, at least one of the first and second modeling material
formulations further comprises an initiator of the non-ROMP
reaction.
[0047] According to some of any of the embodiments of the present
invention, the initiator is comprised in at least one modeling
material formulation which is devoid of the material polymerizable
or curable via the non-ROMP reaction.
[0048] According to some of any of the embodiments of the present
invention, the condition for inducing ROMP of the ROMP monomer and
the condition for inducing polymerization or curing of the non-ROMP
material are the same.
[0049] According to some of any of the embodiments of the present
invention, at least one of the first and the second modeling
material formulations further comprises a toughening agent (e.g.,
an impact modifying agent), a stabilizing agent, a surface active
agent, an elastomeric material or composition, an antioxidant, a
filler, a pigment, and/or a dispersant.
[0050] According to some of any of the embodiments of the present
invention, the first and the second modeling material formulations
form a part of a building material formulation.
[0051] According to some of any of the embodiments of the present
invention, the building material formulation further comprises a
support material formulation.
[0052] According to some of any of the embodiments of the present
invention, a temperature of an inkjet printing head for dispensing
at least the first modeling material formulation ranges from
25.degree. C. to 65.degree. C.
[0053] According to some of any of the embodiments described
herein, a temperature of an inkjet printing head for dispensing the
at least one modeling material formulation ranges from 65.degree.
C. to about 85.degree. C.
[0054] According to some of any of the embodiments of the present
invention, the curing condition is heat and wherein the exposing to
the condition comprises heating the dispensed layers.
[0055] According to some of any of the embodiments of the present
invention, the heating is by infrared radiation.
[0056] According to some of any of the embodiments of the present
invention, the heating is by a ceramic radiation source.
[0057] According to some of any of the embodiments of the present
invention, the dispensing is in a chamber, and wherein the heating
comprises heating the chamber to a temperature of from 25.degree.
C. to 65.degree. C.
[0058] According to some of any of the embodiments of the present
invention, the plurality of layers are formed on a working tray,
the method comprising heating the working tray to a temperature of
from 25.degree. C. to 65.degree. C.
[0059] According to some of any of the embodiments of the present
invention, the dispensing and/or the exposing are performed under
inert atmosphere.
[0060] According to some of any of the embodiments of the present
invention, the method further comprises straightening the layer by
a leveling device.
[0061] According to some of any of the embodiments of the present
invention, the method further comprises removing cured or partially
cured or uncured formulation off the leveling device.
[0062] According to an aspect of some embodiments of the present
invention there is provided a system for three-dimensional
printing, the system comprising:
[0063] a plurality of inkjet printing heads, each having a
plurality of separated nozzles;
[0064] a user interface for receiving a selected ratio between a
first modeling material formulation and a second modeling material
formulation, wherein the first modeling material formulation
comprises a first material, the first material being a first ROMP
monomer, and the second modeling material formulation comprises a
second material that reacts with the ROMP monomer so as to form a
cured model material when exposed to a curing condition, and
wherein at least one of the first and second modeling material
formulations further comprises a catalyst for initiating ROMP of
the monomer; and
[0065] a controller configured for controlling two of the inkjet
printing heads to respectively dispense droplets of the first and
second modeling material formulations in layers, such as to print a
three-dimensional object,
[0066] wherein the controller is configured to form voxel blocks,
wherein, for each block, a ratio between a number of voxels of the
first modeling material formulation in the block and a number of
voxels of the second modeling material formulation in the block
corresponds to the selected ratio.
[0067] According to some of any of the embodiments of the present
invention, the system further comprises a leveling device
configured for straightening at least one of the layers, while at
least one of the modeling material formulations is at a cured or
partially cured or uncured state.
[0068] According to some of any of the embodiments of the present
invention, the leveling device comprises a milling device.
[0069] According to some of any of the embodiments of the present
invention, the leveling device is a self-cleaning leveling device,
wherein the cured or partially cured or uncured formulation is
periodically removed from the leveling device.
[0070] According to some of any of the embodiments of the present
invention, at least one of the inkjet printing heads is configured
to maintain a temperature of at least 25.degree. C. but which does
not exceed 65.degree. C.
[0071] According to some of any of the embodiments of the present
invention, at least one of the inkjet printing heads is configured
to heat at least one modeling material formulation of the building
material formulation prior to the dispensing, and wherein the
controller is configured to ensure that a temperature within the at
least one inkjet printing head is at least 25.degree. C. but not
above 65.degree. C.
[0072] According to some of any of the embodiments of the present
invention, at least one of the inkjet printing heads is configured
to maintain a temperature of from 65.degree. C. to about 85.degree.
C.
[0073] According to some of any of the embodiments of the present
invention, the system further comprises a mixing chamber for
preparing at least one of the modeling material formulations prior
to entry of the at least one modeling material formulation into a
respective head, wherein a position and fluid communication between
the mixing chamber and the respective head is selected such that at
least 80% of the at least one modeling material formulation
entering the respective head remains uncured.
[0074] According to some of any of the embodiments of the present
invention, the system further comprises a ceramic radiation source
for heating the layers by radiation.
[0075] According to some of any of the embodiments of the present
invention, the system further comprises a chamber containing the
plurality of inkjet printing heads, and a chamber heater configured
for heating the chamber, wherein the controller is configured to
maintain, within the chamber, a temperature of at least about
25.degree. C. but no more than 65.degree. C.
[0076] According to some of any of the embodiments of the present
invention, the system further comprises a chamber containing the
plurality of inkjet printing heads, the chamber being generally
sealed to an environment outside the chamber.
[0077] According to some of any of the embodiments of the present
invention, the chamber comprises a gas inlet and the system
comprises a gas source configured for filling the chamber by an
inert gas through the gas inlet.
[0078] According to some of any of the embodiments of the present
invention, the system further comprises a gas outlet, wherein the
controller is configured for generating, continuously or
intermittently, inflow and outflow of the inert gas through the gas
inlet and the gas outlet, respectively.
[0079] According to some of any of the embodiments of the present
invention, the system further comprises a gas flow generating
device, placed within the chamber and configured for generating a
flow of the inert gas within the chamber.
[0080] According to some of any of the embodiments of the present
invention, the system further comprises a working tray for carrying
the layers once formed, and a working tray heater for heating the
working tray.
[0081] According to additional aspects of some embodiments of the
present invention there are provided kits comprising the modeling
material formulations as described in any one of the respective
embodiments and any combination thereof, which, in some
embodiments, are usable in a method as described herein in any one
of the respective embodiments. In some embodiments, each of the
formulations is individually packaged within a kit.
[0082] Unless otherwise defined, all technical and/or scientific
terms used herein have the same meaning as commonly understood by
one of ordinary skill in the art to which the invention pertains.
Although methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the invention, exemplary methods and/or materials
are described below. In case of conflict, the patent specification,
including definitions, will control. In addition, the materials,
methods, and examples are illustrative only and are not intended to
be necessarily limiting.
[0083] Implementation of the method and/or system of embodiments of
the invention can involve performing or completing selected tasks
manually, automatically, or a combination thereof. Moreover,
according to actual instrumentation and equipment of embodiments of
the method and/or system of the invention, several selected tasks
could be implemented by hardware, by software or by firmware or by
a combination thereof using an operating system.
[0084] For example, hardware for performing selected tasks
according to embodiments of the invention could be implemented as a
chip or a circuit. As software, selected tasks according to
embodiments of the invention could be implemented as a plurality of
software instructions being executed by a computer using any
suitable operating system. In an exemplary embodiment of the
invention, one or more tasks according to exemplary embodiments of
method and/or system as described herein are performed by a data
processor, such as a computing platform for executing a plurality
of instructions. Optionally, the data processor includes a volatile
memory for storing instructions and/or data and/or a non-volatile
storage, for example, a magnetic hard-disk and/or removable media,
for storing instructions and/or data. Optionally, a network
connection is provided as well. A display and/or a user input
device such as a keyboard or mouse are optionally provided as
well.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
[0085] Some embodiments of the invention are herein described, by
way of example only, with reference to the accompanying drawings.
With specific reference now to the drawings in detail, it is
stressed that the particulars shown are by way of example and for
purposes of illustrative discussion of embodiments of the
invention. In this regard, the description taken with the drawings
makes apparent to those skilled in the art how embodiments of the
invention may be practiced.
[0086] In the drawings:
[0087] FIG. 1 is a flowchart diagram of a method suitable for
fabricating an object by three-dimensional (3D) inkjet printing
according to aspects of some embodiments of the present
invention.
[0088] FIG. 2 is a schematic illustration of a layer having a
plurality of voxels arranged in blocks, according to some
embodiments of the present invention.
[0089] FIG. 3A is a schematic illustration of two layers, each
having a plurality of voxels arranged in blocks, according to some
embodiments of the present invention.
[0090] FIG. 3B is a schematic illustration of a layer having two
regions, according to some embodiments of the present
invention.
[0091] FIG. 4 is a schematic illustration of a three-dimensional
printing system, according to some embodiments of the present
invention.
[0092] FIGS. 5A and 5B present schematic illustrations of bitmaps
in embodiments of the invention in which a "Drop on Drop" printing
protocol is employed. A bitmap suitable for the deposition of the
first model formulation is illustrated in FIG. 5A and a bitmap
suitable for the deposition of the second model formulation is
illustrated in FIG. 5B. When the droplets of both formulations have
the same or approximately the same weight, the bitmaps are useful
for a 50:50 (or 1:1) w/w ratio. White boxes represent vacant
locations, dotted boxes represent droplets of the first model
formulation and wavy boxes represent droplets of the second model
formulation. Each patterned wavy/dotted box represents a pixel
(e.g., one composition droplet) in a layer. Both model formulations
can be deposited at the same location, but at different times,
during movement of the printing heads.
[0093] FIGS. 6A and 6B present schematic illustrations of bitmaps
in embodiments of the invention in which a "side-by-side" printing
protocol is employed. A bitmap suitable for the deposition of the
first model formulation is illustrated in FIG. 6A and a bitmap
suitable for the deposition of the second model formulation is
illustrated in FIG. 6B. When the droplets of both formulations have
the same or approximately the same weight, the bitmaps are useful
for a 50:50 (or 1:1) w/w ratio. White boxes represent vacant
locations, dotted boxes represent droplets of the first model
formulation and wavy boxes represent droplets of the second model
formulation. Each patterned wavy/dotted box represents a pixel
(e.g., one formulation droplet). A drop of the first composition
(dotted boxes) is deposited adjacent to a drop of the second
composition. Both model formulations may be deposited
simultaneously during movement of the printing heads.
[0094] FIG. 7 is a schematic illustration of a self-cleaning
leveling device, according to some embodiments of the present
invention.
[0095] FIGS. 8A-C are schematic illustrations of printing heads
having arrays of one or more nozzles, according to some embodiments
of the present invention.
DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION
[0096] The present invention, in some embodiments thereof, relates
to three-dimensional printing and, more particularly, but not
exclusively, to methods of performing three-dimensional inkjet
printing, employing ring-opening metathesis polymerization (ROMP),
and to objects obtained by these methods.
[0097] Before explaining at least one embodiment of the invention
in detail, it is to be understood that the invention is not
necessarily limited in its application to the details of
construction and the arrangement of the components and/or methods
set forth in the following description and/or illustrated in the
drawings and/or the Examples. The invention is capable of other
embodiments or of being practiced or carried out in various
ways.
[0098] Herein throughout, the phrase "building material" describes
two major categories of material: `modeling material`, i.e., the
hardened (cured) material that forms the final product (e.g.,
object) of the 3D printing process, and the hardened (cured)
`support material`.
[0099] The support material serves as a supporting matrix for
supporting the object or object parts during the fabrication
process and/or other purposes, e.g., for hollow or porous objects,
or to support overhangs. The support material, when cured, is
preferably water dispersible to facilitate its removal once the
buildup of object is completed. The formulation (composition) used
to form the cured support material is preferably dispensed in
liquid form and is typically curable by radiation, such as, but not
limited to, electromagnetic radiation (e.g., ultraviolet radiation,
visible light radiation, infrared radiation), and electron beam
radiation, so as to form the support material. Also contemplated
are support materials which comprise a wax component, and,
optionally, also a viscosity modifying component. These types of
support materials are in liquid form at the inkjet printing
temperatures, solidify once cooled after being dispensed, and do
not require curing by radiation.
[0100] The modeling material is generally made of a formulation
(composition) which is formulated for use in inkjet technology and
which forms the three-dimensional object, typically upon curing.
The modeling material is generally made of a curable material,
formulated for use in inkjet technology, and which is able to form
the three-dimensional object on its own, i.e., without having to be
mixed or combined with any other substance. An uncured modeling
material formulation is preferably dispensed in liquid form and is
curable by radiation, such as, but not limited to, electromagnetic
radiation (e.g., ultraviolet radiation, visible light radiation,
infrared radiation), and electron beam radiation, or by heat
delivered convectively or conductively, as to form the hardened
(cured) modeling material.
[0101] The phrase "modeling material" is also referred to herein
and in the art as "model material" or simply as "model".
[0102] Herein throughout, the phrases "building material
formulation", "uncured building material", "uncured building
material formulation", and other variations therefore collectively
describe the materials that are dispensed to sequentially form the
layers, as described herein. This phrase encompasses uncured
materials dispensed so as to form the printed object, namely, one
or more uncured modeling material formulation(s), and uncured
materials dispensed so as to form the support, namely uncured
support material formulations.
[0103] Herein, the phrase "printed object" describes the product of
the 3D inkjet process, before the support material, if such has
been used as part of the uncured building material, is removed.
[0104] Herein throughout, the term "object" or "model object"
describes a final product of the 3D inkjet printing process. This
term refers to the product obtained by a method as described
herein, after removal of the support material, if such has been
used as part of the uncured building material. The "object"
therefore essentially consists (at least 95 weight percents) of a
cured modeling material.
[0105] The term "object" as used herein throughout refers to a
whole object or a part thereof.
[0106] The phrase "modeling material", "cured modeling material" or
"hardened modeling material" can be regarded as a cured building
material wherein the building material consists only of a modeling
material formulation (and not of a support material formulation).
That is, this phrase refers to the portion of the building
material, which is used to provide the final object.
[0107] Herein throughout, the phrase "modeling material
formulation", which is also referred to herein interchangeably as
"modeling formulation", "model formulation" or simply as
"formulation", describes a part or all of the uncured building
material which is dispensed so as to form the object, as described
herein. The modeling material formulation is an uncured modeling
formulation (unless specifically indicated otherwise), which, upon
exposure to a condition that effects curing, forms the object or a
part thereof.
[0108] The terms "formulation" and "composition" are used
interchangeably herein throughout.
[0109] In some embodiments of the present invention, a modeling
material formulation is formulated for use in three-dimensional
inkjet printing and is able to form a three-dimensional object on
its own, i.e., without having to be mixed or combined with any
other substance.
[0110] An uncured building material can comprise two or more
modeling formulations, and can be dispensed such that different
parts of the object are made, upon curing, of different cured
modeling formulations, and hence are made of different cured
modeling materials or different mixtures of cured modeling
materials.
[0111] In some embodiments of the invention both the hardened
(cured) support and model materials are obtained using the same
type of curing.
[0112] The phrase "multi-material model", as used herein and in the
art, describes an object (model) featuring macroscopic domains of
different modeling materials in at least a portion thereof, for
example, a printed object that is comprised of portions having
different properties, e.g. mechanical properties, such as
flexibility, rigidity, elasticity and so on, such that, for
example, an object may comprise a combination of a flexible portion
and a rigid portion. This phrase encompasses an object featuring
domains of different modeling materials, wherein the modeling
materials differ from one another by the ratio of the compositions
(formulations) that are used to form the modeling material.
[0113] The phrase "digital materials", as used herein and in the
art, describes a combination of two or more materials on a
microscopic scale or voxel level such that the printed zones of a
specific material are at the level of few voxels. Such digital
materials may exhibit new properties that are affected by the
selection of types of materials and/or the ratio and relative
spatial distribution of two or more materials, at the voxel level,
as described herein.
[0114] In exemplary digital materials, the modeling material of
each voxel or voxel block, obtained upon curing, is independent of
the modeling material of a neighboring voxel or voxel block,
obtained upon curing, such that each voxel or voxel block may
result in a different model material and the new properties of the
whole part are a result of a spatial combination, on the voxel
level, of several different model materials.
[0115] The present inventors have now designed a methodology for
inkjet printing, via separate printing heads, two or more model
formulations, which form a part of the building formulation, and
which provide, upon chemically reacting with one another, a
hardened (cured) building (e.g., modeling) material. Thus, the
chemical composition of the hardened building (e.g., modeling)
material can be digitally controlled, by controlling the ratio of
the jetted formulations at a voxel level.
[0116] Changing the ratio of voxels of each formulation which are
adjacent to one another, results in cured materials which exhibit
different chemical structures/compositions and different chemical,
physical and/or mechanical properties, whereby these structures and
properties are controllable at a level of few voxels (e.g., from 2
to 100 voxels or from 2 to 80 voxels or from 2 to 60 voxels or from
2 to 50 voxels or from 2 to 40 voxels or from 2 to 30 voxels or
from 2 to 20 voxels or from 2 to 10 voxels or from 2 to 8 voxels or
from 2 to 6 voxels or from 2 to 4 voxels or from 10 to 80 voxels or
from 10 to 60 voxels or from 10 to 40 voxels).
[0117] Such a methodology results in printed objects in which the
properties of portions of these objects are controlled at a
resolution of a few voxels.
[0118] Embodiments of the present invention describe a methodology
of fabricating 3D objects, by 3D inkjet printing, while employing
ROMP systems, and while controlling the properties of portions of
these objects at a resolution of a few voxels.
[0119] In some of any of the embodiments described herein, at least
one of the modeling material formulations as described herein
comprises a monomer that is polymerizable by ring opening
metathesis polymerization (ROMP). Such a monomer is also referred
to herein interchangeably as a ROMP monomer, a ROMP-polymerizable
monomer, a ROMP curable monomer, a ROMP component, a ROMP active
component, and similar diversions. In some embodiments, one or more
of the modeling material formulations in the uncured building
material comprises a catalyst for initiating a ROMP reaction of the
monomer, as described in further detail hereinunder.
[0120] In some of any of the embodiments described herein, the ROMP
monomer is an unsaturated cyclic monomer, preferably a strained
unsaturated cyclic olefin, as described in further detail
hereinunder.
[0121] The Method:
[0122] According to aspects of some embodiments of the present
invention, there is provided a method of three-dimensional (3D)
inkjet printing of a three-dimensional object. According to
embodiments of these aspects, the method is generally effected by
sequentially forming a plurality of layers in a configured pattern
corresponding to the shape of the object, thereby forming the
object.
[0123] According to embodiments of these aspects, formation of each
layer is effected by dispensing a building material formulation
(uncured building material) which comprises at least a first and a
second modeling material formulations, as described herein, and
exposing the dispensed building material formulation to condition
which affect curing of the formulation to thereby obtain a cured
building material.
[0124] When three-dimensional inkjet printing is employed, a
building material formulation is dispensed from a dispensing head
having one or more, preferably a set of, nozzles to deposit the
building material in layers on a supporting structure. The inkjet
printing system thus dispenses building material formulation(s) in
target locations which are to be occupied and leaves other target
locations void. The inkjet printing typically includes a plurality
of dispensing heads, each of which can be configured to dispense a
different building material formulation. Thus, different target
locations can be occupied by different building materials.
[0125] In some exemplary embodiments of the invention an object is
manufactured by dispensing a building material formulation that
comprises two or more different modeling material formulations,
each modeling material formulation from a different dispensing head
of the inkjet printing apparatus. The modeling material
formulations are optionally and preferably deposited in layers
during the same pass of the printing heads. The modeling material
formulations within the layer are selected according to the desired
properties of the object, as described in further detail
hereinafter.
[0126] FIG. 1 is a flowchart diagram of a method suitable for
fabricating an object by three-dimensional (3D) inkjet printing
according to aspects of some embodiments of the present invention.
It is to be understood that, unless otherwise defined, the
operations described hereinbelow can be executed either
contemporaneously or sequentially in many combinations or orders of
execution. Specifically, the ordering of the flowchart diagrams is
not to be considered as limiting. For example, two or more
operations, appearing in the following description or in the
flowchart diagrams in a particular order, can be executed in a
different order (e.g., a reverse order) or substantially
contemporaneously. Additionally, several operations described below
are optional and may not be executed.
[0127] The method begins at 10 and optionally and preferably
continues to 11 at which 3D printing data corresponding to the
shape of the object is received. The data can be received, for
example, from a host computer which transmits digital data
pertaining to fabrication instructions based on computer object
data, e.g., in a form of a Standard Tessellation Language (STL) or
a StereoLithography Contour (SLC) format, Virtual Reality Modeling
Language (VRML), Additive Manufacturing File (AMF) format, Drawing
Exchange Format (DXF), Polygon File Format (PLY) or any other
format suitable for Computer-Aided Design (CAD).
[0128] At 12 a ratio between a first modeling material formulation
(a first composition) and a second modeling material formulation (a
second composition) is received. While the embodiments below are
described with a particular emphasis on a ratio between two
formulations, it is to be understood that more detailed reference
to a ratio between two formulations is not to be interpreted as
indicating that embodiments in which a ratio between more than two
formulations (e.g., modeling material formulations) are not
contemplated. Thus, embodiments of the present invention
contemplate receiving a ratio between N formulations, where N is at
least 2, and can be 2, 3, 4, or more. The ratio is typically
expressed in terms of the volumes of the respective formulations,
but may also be expressed in terms of other extensive physical
properties, such as the weights of the respective compositions. A
representative example of a received ratio for two compositions is
X1:X2, where X1 and X2 are the extensive physical properties (e.g.,
weight, volume) of the first and second modeling material
formulations. A representative example of a received ratio for
three or more formulations is X1:X2: . . . :XN, where N is the
number of the formulations (N>2, in the present example) and X1,
X2, . . . , XN are the extensive physical properties (e.g., weight,
volume) of the respective formulations.
[0129] The ratio can be received as a user input or can be obtained
from an external source, such as, but not limited to, a computer
that calculates the ratio and transmits it to the method. At least
two of the modeling material formulations comprise substances
(materials) that react (e.g., chemically) with one another to form
a building (e.g., modeling) material. The properties of the
building (e.g., modeling) material that is formed by the (e.g.,
chemical) reaction typically depend on the selected ratio. The
computer can thus calculate the ratio based on the desired
properties of the building (e.g., modeling) material. Also
contemplated are embodiments in which instead of receiving the
ratio the method receives building (e.g., modeling) material
properties and calculates the ratio based on the received
properties.
[0130] Optionally, the method continues to 13 at which the first
and/or second modeling material formulations are heated. These
embodiments are particularly useful for modeling material
formulations that have relatively high viscosity at the operation
temperature of the working chamber of the 3D printing system. The
heating of the formulation(s) is preferably to a temperature that
allows jetting the respective composition through a nozzle of a
printing head of a 3D printing system. In some embodiments of the
present invention, the heating is to a temperature at which the
respective formulation exhibits a viscosity in a range of from
about 8 centipoises and up to no more than X centipoises, where X
is about 35 centipoises, or about 30 centipoises, preferably about
25 centipoises and more preferably about 20 centipoises, or 18
centipoises, or 16 centipoises, or 14 centipoises, or 12
centipoises, or 10 centipoises, and at which the formulation cannot
undergo thermal curing (e.g., below a temperature at which curing,
as defined herein, can be effected). Thus, denoting the temperature
at which the viscosity of the respective composition is X
centipoises by T.sub.1 and the temperature at which thermal curing
is effected for that composition by T.sub.2, the heating at 13 is
preferably to a temperature T satisfying
T.sub.1<T<T.sub.2.
[0131] The heating 13 can be executed before loading the respective
formulation into the printing head of the 3D printing system, or
while the formulation is in the printing head or while the
formulation passes through the nozzle of the printing head.
[0132] In some embodiments, heating 13 is executed before loading
of the respective composition into the printing head, so as to
avoid clogging of the printing head by the formulation in case its
viscosity is too high.
[0133] In some embodiments, heating 13 is executed by heating the
printing heads, at least while passing the first and/or second
modeling material formulation(s) through the nozzle of the printing
head.
[0134] In some embodiments, both the first and second (or all
other) formulations are heated, and in some embodiments, only one
(or more) of the formulations is heated, while the other
formulation(s) exhibit a desired viscosity of less than 35 or less
than 30, or less than 25 centipoises at ambient temperature.
[0135] In some embodiments, a temperature of an inkjet printing
head for dispensing a modeling material formulation which comprises
one or more monomers that undergo polymerization via ROMP, as
described herein, is lower than 70.degree. C., and ranges, for
example, from about 25.degree. C. to about 65.degree. C., including
any subranges and intermediate values therebetween.
[0136] In some embodiments, higher temperatures of an inkjet
printing head are required, for example, higher than 70.degree. C.,
or ranging from about 65.degree. C. to about 95.degree. C., or
about 65.degree. C. to about 85.degree. C., including any subranges
and intermediate values therebetween. Modeling material
formulations which comprise curable materials which are
polymerizable by non-ROMP reactions, as described herein (for
example, UV-curable acrylates and methacrylates, and/or epoxy
monomers useful for cationic photopolymerization), as curable
components, optionally in addition to ROMP-curable components, are
suitable for use in the context of these embodiments.
[0137] In some embodiments, the method does not include heating
13.
[0138] The method continues to 14 at which droplets of the
compositions are dispensed in layers, on a receiving medium, using
at least two different multi-nozzle inkjet printing heads,
according to the printing data. The receiving medium can be a tray
of a three-dimensional inkjet system or a previously deposited
layer.
[0139] In some embodiments of the present invention, the dispensing
14 is effected under a generally inert environment.
[0140] As used herein "inert environment" means an environment that
is substantially free of oxygen, carbon dioxide, water and/or any
other substances that may chemically react with the first and
second formulations or otherwise interfere in the polymerization
reaction.
[0141] As used herein, "substantially free" means less than 1% or
less than 0.5%, or less than 0.1%, or less than 0.05%, or less than
0.01% of a substance that may interfere in the chemical
reaction.
[0142] An inert environment can be established by supplying an
inert gas or an inert gas mixture into the working chamber of the
3D printing system. Representative examples of an inert gas
include, but are not limited to, nitrogen and/or argon.
[0143] In some embodiments, the inert environment is a dry inert
environment, such as dry nitrogen and/or argon.
[0144] Accordingly, as used herein, "inert" environment or "inert"
atmosphere is not limited to an environment consisting of inert
gases, but can mean either an inert gas, a mixture of inert gases,
or a vacuum.
[0145] Once the uncured building material is dispensed on the
receiving medium according to the 3D printing data, the method
optionally and preferably continues to 15 at which the deposited
layers are exposed to a curing condition, as described herein.
[0146] Preferably, each individual layer is exposed to this
condition following or during the deposition of the layer, and
prior to the deposition of the subsequent layer.
[0147] In some embodiments, exposing to conditions that effect
curing is performed under a generally dry and inert environment, as
described herein.
[0148] In these embodiments, the dry and inert environment is
optionally and preferably prepared before the material is dispensed
so that 15 can be executed simultaneously with 14 wherein the
material is exposed to the environment upon exiting the inkjet
printing head.
[0149] In some embodiments, the exposure 15 can include exposing
the dispensed layer to radiation, such as, but not limited to,
electromagnetic radiation, for example, infrared radiation (e.g.,
at a wavelength of from about 800 nm to about 4 .mu.m), ultraviolet
radiation (e.g., at a wavelength of from about 200 nm to about 400
nm) and visible or near-visible light radiation (e.g., at a
wavelength of from about 400 nm to about 800 nm), or particle
radiation, for example in the form of an electron beam, depending
on the modeling material being used. Preferably, but not
necessarily, the infrared radiation is applied by a ceramic lamp,
for example, a ceramic lamp that produces infrared radiation of
from about 3 .mu.m to about 4 .mu.m, e.g., about 3.5 .mu.m, or of
any other wavelength suitable for efficient application of heat, as
discussed hereafter. Alternatively or additionally, the exposure 15
can include exposing the dispensed layer to elevated temperature,
for example, from about 25.degree. C. to about 100.degree. C., or
from about 25.degree. C. to about 65.degree. C., or from about
65.degree. C. to about 100.degree. C. Higher temperatures (for
example, above 100.degree. C. or from about 100.degree. C. to about
900.degree. C., or from about 200.degree. C. to about 900.degree.
C., e.g., about 300.degree. C., or from about 300.degree. C. to
about 900.degree. C. or from about 400.degree. C. to about
900.degree. C.) are also contemplated. The elevated temperatures
can be generated by heating the tray on which the layers are
dispensed, and/or the chamber within which the printing process is
executed, and/or by using a resistive heater, or by heat-inducing
irradiation, using a radiation source as described herein, at a
suitable wavelength for providing a required temperature. A ceramic
lamp, for example, when operated at the above-described
wavelengths, may result in heating a dispensed formulation to up to
300.degree. C., and even to a temperature of from about 400.degree.
C. to about 900.degree. C. In some embodiments, exposure 15
comprises two or more different curing conditions. In some of these
embodiments, the dispensed droplets are exposed to a first curing
condition and to a second, different curing condition. For example,
the first curing condition can be in the form of UV radiation and
the second curing condition can be in the form of thermal energy
delivered by convection, conduction and/or radiation.
[0150] In some embodiments, exposing to a curing condition is
effected under a generally dry and inert environment, as described
herein.
[0151] The method can preferably continue to 16 at which the
deposited layer is straightened, for example, by a leveling device.
Optionally, the layer is straightened after at least one of the
dispensed formulations is cured. Alternatively, the layer is
straightened while at least one of the dispensed formulations is
still uncured. In some embodiments, straightening of a layer is
performed so as to provide a certain (e.g., pre-determined)
thickness of the layer, to thereby provide a plurality of layers in
which a thickness of at least one, and preferably two or more, of
the layers is controlled.
[0152] As used herein the phrase "cured" refers to a formulation
that underwent curing or at least a partial curing, as defined
herein, and encompasses a state of the formulation in which at
least 20% or at least 30% or at least 40% or at least 50% or at
least 60% or at least 70% of the formulation underwent curing, as
defined herein, and a state of a formulation that underwent up to
100% curing.
[0153] Typically, a formulation that underwent curing or partial
curing is characterized by a viscosity that is substantially higher
than an uncured formulation, and preferably, a formulation, or at
least a part thereof, solidifies upon curing. A "cured" formulation
is also referred to interchangeably as a "hardened" formulation or
as a "solidified" formulation.
[0154] Straightening or leveling of a layer or layers after curing
(or partial curing) can be achieved by a leveling device that is
capable of reforming the solidified portion of the formulation or
removing part thereof. A representative example of such a leveling
device is a roller capable of milling, grinding and/or flaking a
solidified formulation or part thereof. Straightening can be
achieved by a leveling device that is capable of leveling the
formulation in its liquid, gel, partially-cured or cured state.
[0155] In some embodiments, the leveling device effects milling,
grinding and/or flaking, and/or removes at least part of the top of
a layer of the formulation. Such a leveling device can be, for
example, a roller, a blade or a cutter.
[0156] In some embodiments of the present invention the method
continues to 17 at which cured, partially cured or uncured
formulation is removed off the leveling device. These embodiments
are particularly useful when the leveling device is applied to the
layer while the formulation is uncured or partially cured. In this
case, a portion of the formulation collected by the leveling device
can experience curing or partial curing while the formulation is on
the leveling device (for example on the roller, when the leveling
device comprises a roller), and the method preferably removes such
cured or partially cured formulation from the device. These
embodiments can also be useful when the leveling device is applied
to the layer while the formulation is cured (for example, when the
leveling device effects milling, grinding, flaking and/or removing
part of the solidified portion of the formulation). In this case
the method removes the debris of the milling, grinding, flaking
and/or material removal process from the leveling device, using for
example a suction device.
[0157] Operation 17 is preferably executed automatically and
optionally also continuously while the leveling device is in motion
over the layer. For example, the leveling device can comprise a
double roller having a first roller that contacts and straightens
the layer and a second that is in contact with the first roller but
not with the layer and which is configured to remove the
formulation from the first roller.
[0158] The method ends at 18.
[0159] In some of any of the embodiments described herein, the
method is effected such that for at least one region of the object,
the dispensing of the droplets is selected to form voxel blocks,
wherein, for each block, a ratio between a number of voxels of the
first composition (the first model formulation) in the block and a
number of voxels of the second composition (the second model
formulation) in the block corresponds to the selected ratio between
the at least first and second model formulations.
[0160] These embodiments are illustrated in FIG. 2 which shows a
layer 20 having a plurality of voxels 22 arranged in blocks 24.
[0161] Herein throughout, the term "voxel" describes a volume
element deposited by a single nozzle of a three-dimensional
printing system.
[0162] Herein throughout, the term "voxel block" describes a group
of voxels wherein each voxel in the group is adjacent to at least
one other voxel in the group.
[0163] Voxels occupied with the first modeling material formulation
are shown in FIG. 2 as white and voxels occupied with the second
modeling material formulation are marked in FIG. 2 with hatching.
In the representative example of FIG. 2, which is not intended to
be limiting, each block includes 9 voxels, wherein the ratio
between a number of voxels of the first modeling material
formulation and a number of voxels of the second modeling material
formulation in the block is 8:1.
[0164] In various exemplary embodiments of the invention the ratio
8:1 corresponds to the ratio received or calculated at 12. For
example, when the same amount (e.g., weight, volume) of modeling
material formulation is deposited onto each voxel, the ratio
between the number of voxels can be the same as the ratio received
or calculated at 12. When the amount of formulation in a voxel
occupied with the first modeling material formulation is not the
same as the amount of formulation in a voxel occupied with the
second modeling material formulation, the ratio between the numbers
of voxels is obtained by correcting the ratio received or
calculated at 12 using the amounts in the respective voxels. In
other words, the ratio between the numbers of voxels in a block is
selected such that the ratio between the amounts of formulations
deposited within the block approximately equals the ratio received
or calculated at 12. As a representative example, consider a
process in which the method receives a ratio X1:X2=4:1, and in
which the amount of the first modeling material formulation per
voxel is 2 times the amount of the second modeling material
formulation per voxel. In this case, a ratio of 8:1 between the
number of voxels corresponds to a ratio of 4:1 between the amounts
since 8/2=4/1. The correction of the ratio the ratio received or
calculated at 12 using the amounts in the respective voxels, can be
done by a controller that is integrated in the three-dimensional
printing system (e.g., controller 152, see FIG. 4 described below),
or, alternatively by a data processor or a computer that is
external to the three-dimensional printing system (e.g., computer
154, see FIG. 4 described below).
[0165] In some embodiments, a ratio is selected between a first
modeling material formulation and a second modeling material
formulation.
[0166] In some embodiments, a ratio is selected between three or
more compositions, that is a first modeling material formulation, a
second modeling material formulation, a third modeling material
formulation, and optionally a fourth modeling material formulation,
a fifth modeling material formulation and so on.
[0167] For simplicity, the following description relates to
embodiments where a first and a second modeling material
formulations are used. However, it is to be noted that embodiments
in which more than two modeling material formulations are utilized
are also contemplated, as stated hereinabove.
[0168] In some embodiments, each voxel block as defined herein
comprises from 2 to 100 voxels or from 2 to 80 voxels or from 2 to
60 voxels or from 2 to 50 voxels or from 2 to 40 voxels or from 2
to 30 voxels or from 2 to 20 voxels or from 2 to 10 voxels or from
2 to 8 voxels or from 2 to 6 voxels or from 2 to 4 voxels or from
10 to 80 voxels or from 10 to 60 voxels or from 10 to 40
voxels.
[0169] In some preferred embodiments of the invention each droplet
occupies a single voxel upon deposition of the droplet. Thereafter,
and before curing, the droplet may spread to one or more adjacent
voxels.
[0170] It is appreciated that more than one ratio between the
formulations can be received or calculated. When more than one
ratio between the formulations is employed, different ratios can
correspond to different layers or different regions in the same
layer. These embodiments are illustrated in FIGS. 3A and 3B.
[0171] FIG. 3A illustrates two layers 20a and 20b, each having a
plurality of voxels 22 arranged in blocks 24. In layer 20a each
block includes 3 voxels of the first modeling material formulation
and 1 voxel of the second modeling material formulation, and in
layer 20b each block includes 8 voxel of the first modeling
material formulation and 1 voxel of the second modeling material
formulation. Since different ratios between the formulations
correspond to different properties of the building (e.g., modeling)
material formed by the reaction of the formulations with each
other, the different ratios in layers 20a and 20b can be selected
to ensure that the properties of the building (e.g., modeling)
materials formed in each layer are also different.
[0172] FIG. 3B illustrates a layer 20 having two regions designated
26 and 28. In the representative example of FIG. 3B, which is not
intended to be limiting, each block in region 26 includes 9 voxels,
and each block in region 28 includes 12 voxels. Region 26 includes
blocks of voxels wherein the ratio between a number of voxels of
the first modeling material formulation and a number of voxels of
the second modeling material formulation in each block is 8:1; and
region 28 includes blocks of voxels wherein the ratio between a
number of voxels of the first modeling material formulation and a
number of voxels of the second modeling material formulation in
each block is 12:2.
[0173] Since different ratios between the formulations correspond
to different properties of the building (e.g., modeling) material
formed by the reaction of the substances in the formulations with
each other, the different ratios in regions 26 and 28 can be
selected to ensure that the properties of the building (e.g.,
modeling) materials formed in each region of the same layer are
also different.
[0174] In any of the above embodiments, the first and second
modeling material formulations begin to mix within each block 24
following their deposition on the receiving medium, typically upon
being exposed to curing condition. The mixing and/or curing results
in a building (e.g., modeling) material which is optionally and
preferably chemically (and/or physically) different to any of the
first and second modeling material formulations and which occupies
most or all the voxels in the respective block 24. Preferably, the
distribution of the building (e.g., modeling) material, once
formed, is generally uniform over the entire block 24.
[0175] As used herein "generally uniform distribution" means a
deviation from uniformity of less than 30% or 20% or less than 10%
or less than 5%.
[0176] The distribution of the building (e.g., modeling) material
can be measured with respect to any extensive property, including,
without limitation, weight and volume.
[0177] In some embodiments, all the voxels in at least one voxel
block participate in a reaction between the first and second
modeling material formulations, such that the cured building
material that results from the reaction, following the exposure to
the curing energy, is substantially homogenous.
[0178] As used herein, "substantially homogenous" means that the
building material in a voxel block vary in weight percent of its
ingredients by less than 10% or less than 8% or less than 6% or
less than 4% or less than 2% or less than 1% or less than 0.5% or
less than 0.25%.
[0179] To ensure reaction between the first and second modeling
material formulations, the deposition of the compositions can be
performed in more than one way.
[0180] In some embodiments of the present invention a "Drop on
Drop" printing protocol is employed. These embodiments are
schematically illustrated in FIGS. 5A and 5B. A bitmap suitable for
the deposition of the first modeling material formulation is
illustrated in FIG. 5A and a bitmap suitable for the deposition of
the second modeling material formulation is illustrated in FIG. 5B.
White boxes represent vacant locations, dotted boxes represent
droplets of the first modeling material formulation and wavy boxes
represent droplets of the second modeling material formulation. The
printing data in these embodiments are such that for each layer,
both modeling material formulations are deposited at the same
location, but different times, during movement of the printing
head. For example, each droplet of a first modeling material
formulation can be jetted on top of a droplet of a second modeling
material formulation, or vice versa. Preferably, but not
necessarily, the two formulation parts are jetted in drops at the
same weight and/or rate. These embodiments are particularly useful
when the desired weight ratio is 1:1. For other desired weight
ratios, the two formulation parts are preferably jetted in drops of
different weights, wherein the ratio of the weights corresponds to
the desired ratio.
[0181] A representative example for a resolution suitable for the
present embodiments is 1200 dpi in the X direction and 300 dpi in
the Y direction. The drop on drop printing protocol allows the two
types of drops to combine and mix before the crystallization of
deposited material.
[0182] In some embodiments of the present invention a "side by
side" printing protocol is employed. These embodiments are
schematically illustrated in FIGS. 6A and 6B. A bitmap suitable for
the deposition of the first modeling material formulation is
illustrated in FIG. 6A and a bitmap suitable for the deposition of
the second modeling material formulation is illustrated in FIG. 6B.
The colors of the white, dotted and wavy boxes represent vacant
locations, droplets of the first modeling material formulation and
droplets of the second modeling material formulation, respectively.
The printing data in these embodiments is such that for each layer,
each drop of a first modeling material formulation is jetted
adjacent to a drop of a second modeling material formulation, or
vice versa. Due to drop spreading, the adjacent drops tend to
partially overlap. As a result, the two drops diffuse toward each
other, mix and react after deposition.
[0183] In the schematic illustrations shown in FIGS. 5A-6B,
chessboard bitmaps are illustrated, but this need not necessarily
be the case, since, for some applications, other bitmap patterns
can be employed.
[0184] In some of any of the embodiments described herein, the
building material further comprises one or more support
materials.
[0185] In some of any of the embodiments described herein,
dispensing a building material formulation further comprises
dispensing one or more support material formulation(s).
[0186] Dispensing the support material formulation, in some
embodiments, is effected by inkjet printing head(s) other than the
inkjet printing heads used for dispensing the modeling material
formulation(s).
[0187] In some embodiments, exposing the building material to a
condition that induces curing includes one or more conditions that
affect curing of a support material formulation, to thereby obtain
a cured support material.
[0188] In some of any of the embodiments described herein, once a
building material is cured, the method further comprises removing
the cured support material. Any of the methods usable for removing
a support material can be used, depending on the materials forming
the modeling material and the support material. Such methods
include, for example, mechanical removal of the cured support
material and/or chemical removal of the cured support material by
contacting the cured support material with a solution in which it
is dissolvable (e.g., an alkaline aqueous solution).
[0189] As used herein, the term "curing" describes a process in
which a formulation is hardened. This term encompasses
polymerization of monomer(s) and/or oligomer(s) and/or
cross-linking of polymeric chains (either of a polymer present
before curing or of a polymeric material formed in a polymerization
of the monomers or oligomers). The product of a curing reaction is
therefore typically a polymeric material and in some cases a
cross-linked polymeric material. This term, as used herein,
encompasses also partial curing, for example, curing of at least
20% or at least 30% or at least 40% or at least 50% or at least 60%
or at least 70% of the formulation, as well as 100% of the
formulation.
[0190] Herein, the phrase "a condition that affects curing" or "a
condition for inducing curing", which is also referred to herein
interchangeably as "curing condition" or "curing inducing
condition" describes a condition which, when applied to a
formulation that contains a curable material, induces
polymerization of monomer(s) and/or oligomer(s) and/or
cross-linking of polymeric chains. Such a condition can include,
for example, application of a curing energy, as described
hereinafter to the curable material(s), and/or contacting the
curable material(s) (e.g., ROMP monomer) with chemically reactive
components such as other components of a ROMP catalyst system
(e.g., catalysts, co-catalysts, and/or activators).
[0191] When a condition that induces curing comprises application
of a curing energy, the phrase "exposing to a condition that
affects curing" means that the dispensed layers are exposed to the
curing energy and the exposure is typically performed by applying a
curing energy to the dispensed layers.
[0192] A "curing energy" typically includes application of
radiation or application of heat, as described herein.
[0193] A curable material or system that undergoes curing upon
exposure to electromagnetic radiation (e.g., as described herein)
is referred to herein interchangeably as "photopolymerizable" or
"photoactivatable" or "photocurable".
[0194] When the curing energy comprises heat, the curing is also
referred to herein and in the art as "thermal curing" and comprises
application of thermal energy. Applying thermal energy can be
effected, for example, by heating a receiving medium onto which the
layers are dispensed or a chamber hosting the receiving medium, as
described herein. In some embodiments, the heating is effected
using a resistive heater.
[0195] In some embodiments, the heating is effected by irradiating
the dispensed layers by heat-inducing radiation. Such irradiation
can be effected, for example, by means of an IR lamp or Xenon lamp,
operated to emit radiation onto the deposited layer.
[0196] In some embodiments, heating is effected by infrared
radiation applied by a ceramic lamp, for example, a ceramic lamp
that produces infrared radiation of from about 3 .mu.m to about 4
.mu.m, e.g., about 3.5 .mu.m.
[0197] In some embodiments, the heat-inducing radiation is selected
to emit radiation at a wavelength that results in efficient
absorption of the heat energy by a selected ROMP monomer or mixture
of monomers, so as to effect efficient application of heat energy
(efficient heating or thermal curing).
[0198] A curable material or system that undergoes curing upon
exposure to heat is referred to herein as "thermally-curable" or
"thermally-activatable" or "thermally-polymerizable".
[0199] In some of any of the embodiments described herein, the
method further comprises exposing the cured modeling material
formulation(s) either before or after removal of a support
material, if such has been included in the building material, to a
post-treatment condition. The post-treatment condition is typically
aimed at further hardening the cured modeling formulation(s) and/or
at preventing its oxidation. In some embodiments, the
post-treatment hardens a partially-cured formulation to thereby
obtain a completely cured formulation.
[0200] In some embodiments, the post-treatment is effected by
exposure to heat or radiation, preferably at a reduced pressure
(e.g., vacuum), and optionally at atmospheric pressure under inert
atmosphere, as described in any of the respective embodiments
herein. In some embodiments, when the condition is heat, the
post-treatment can be effected for a time period that ranges from a
few minutes (e.g., 10 minutes) to a few hours (e.g., 1-24 hours,
preferably 1-5 hours), and at a temperature of e.g., above
100.degree. C., for example, at a temperature in a range of
100-200.degree. C., or, for example, at 150.degree. C., and at a
reduced pressure.
[0201] An inert atmosphere can be, for example, nitrogen and/or
argon atmosphere.
[0202] Reduced pressure can be, for example, lower than 200 mmHg,
lower than 100 mmHg, or lower than 50 mmHg, for example, about 20
mmHg, although any other value is contemplated.
[0203] Alternatively, or in addition, the post-curing treatment
comprises applying to a surface of (or coating) the model object,
or to a part of the surface, a material or a composition that
features anti-oxidation activity, to thereby reduce or prevent
oxidation of the model object (or a part thereof) when exposed to
ambient environment. In some of these embodiments, the material or
composition is such that form a thin, preferably, but not
necessarily transparent, layer on the surface of the model object
or a part thereof. Any material or composition that feature
anti-oxidation activity and which can be readily applied to the
model object as described herein is contemplated. An exemplary such
composition is an acrylic paint, that is, a formulation that forms
an acrylic paint once deposited on a surface of the object.
[0204] Applying a material or composition featuring an
anti-oxidation activity and exposing to heat or radiation, within a
post-curing treatment as described herein, when used together, can
be effected sequentially or simultaneously. For example, a
formulation forming an acrylic paint can be applied to the surface
of the model object, and exposure to heat and/or radiation can be
applied thereafter, to thereby effect both formation of a layer of
the acrylic paint and further hardening of the cured modeling
formulation.
[0205] In some of any of the embodiments described herein, at least
one of the modeling material formulations as described herein
comprises a monomer that is polymerizable by ring opening
metathesis polymerization (ROMP). Such a monomer is also referred
to herein interchangeably as a ROMP monomer, a ROMP-polymerizable
monomer, a ROMP curable monomer, a ROMP component, a ROMP active
component, and similar diversions. In some embodiments, one or more
of the modeling material formulations in the (uncured) building
material comprises a catalyst for initiating a ROMP reaction of the
monomer, as described in further detail hereinunder.
[0206] In some of any of the embodiments described herein, the ROMP
monomer is an unsaturated cyclic monomer, preferably a strained
unsaturated cyclic olefin, as described in further detail
hereinunder.
[0207] In some of any of the embodiments described herein, exposing
the modeling material formulation to a condition that induces
curing comprises exposing the dispensed modeling material
formulation(s) to a condition for inducing initiation of ROMP of
the monomer by the catalyst, as described in further detail
hereinunder. Any of the conditions for effecting curing as
described hereinabove are contemplated, depending on the materials
selected for the ROMP system.
[0208] Herein throughout, a condition for inducing initiation of
ROMP of the monomer by the catalyst is also referred to herein
interchangeably as "a ROMP inducing condition" or simply as
"inducing condition", and describes a condition to which a modeling
material formulation is exposed so as to effect ROMP of the ROMP
monomer (e.g., to effect initiation of ROMP of the ROMP monomer by
the catalyst). In some embodiments, the ROMP inducing condition is
a curing condition.
[0209] It is to be noted that a building material, including the
one or more modeling material formulations included therein, can be
exposed also to a condition that affects curing via other modes of
action (e.g., via other polymerization reactions and/or via
cross-linking of polymeric chains), that is, a non-ROMP curing
condition, as described in further detail hereinafter.
[0210] The ROMP inducing condition and a non-ROMP curing condition
can be the same or different.
[0211] A ROMP System:
[0212] Herein, a "ROMP system" describes a set of materials and
optionally conditions for effecting polymerization, via a ROMP
reaction, of an unsaturated cyclic ROMP monomer (or a mixture of
ROMP monomers). The materials included in a ROMP system are also
referred to herein as "ROMP components" or "ROMP active
components".
[0213] A ROMP system requires at least a ROMP monomer and a
catalyst for initiating the ROMP reaction. The catalyst is also
referred to herein throughout as a "ROMP catalyst" or a "ROMP
catalyst system".
[0214] In some embodiments, a ROMP system consists of a catalyst
and a ROMP monomer. In such cases, the catalyst in referred to
herein as an "active catalyst", which is active towards initiation
of ROMP of the monomer immediately once it contacts the monomer,
without a need to apply an external stimulus such as, for example,
heat, radiation, or chemical additives.
[0215] In some of these embodiments, a condition for inducing
initiation of ROMP of the monomer by the catalyst requires
contacting the catalyst with the ROMP monomer.
[0216] By "active towards initiation of ROMP" of the monomer it is
meant that in the presence of the catalyst, at least 50% or at
least 60% or at least 70% or at least 80% of the monomer
polymerizes via ROMP mechanism to provide a respective polymer.
[0217] In some embodiments, a ROMP system consists of a catalyst
and a ROMP monomer and a condition for activating the catalyst
towards initiation of ROMP of the monomer. In such cases, the
catalyst is referred to herein as a "latent catalyst", which is
activatable upon exposure to the condition. According to some of
these embodiments, the catalyst is inactive towards initiation of
ROMP of the monomer when the ROMP system is not exposed to the
condition that activates the catalyst, namely, prior to exposure to
a ROMP inducing condition.
[0218] By "inactive towards initiation of ROMP" of the monomer it
is meant that in the presence of the catalyst, no more than 40% or
no more than 30% or no more than 20% or no more than 10% or no more
than 5% of the monomer polymerizes via ROMP mechanism to provide a
respective polymer.
[0219] Latent catalysts as described herein can be
thermally-activatable catalysts, which are converted into active
catalysts upon exposure to heat (that is, a condition for inducing
initiation of ROMP comprises heat or heating a ROMP system,
optionally in addition to contacting the catalyst and the ROMP
monomer).
[0220] Latent catalysts as described herein can be
photo-activatable catalysts, which are converted into active
catalysts upon exposure to radiation (that is, a condition for
inducing initiation of ROMP comprises exposure to radiation or
application of radiation to the ROMP system, optionally in addition
to contacting the catalyst and a ROMP monomer). The radiation can
be, for example, an electromagnetic radiation (e.g., UV or visible
or IR light), or ultrasound radiation, or heat-inducing radiation,
and can be applied by a suitable source of the radiation, as
described herein.
[0221] Latent catalysts activatable by exposure to other conditions
are also contemplated.
[0222] In some embodiments, a ROMP system consists of a ROMP
monomer, a ROMP catalyst and an activator, for chemically
activating the ROMP catalyst. In such cases, the ROMP catalyst is
inactive towards initiation of ROMP of the monomer, as defined
herein, in the absence of the activator (when it is not contacted
with the activator). A ROMP catalyst that is activatable in the
presence of an activator is referred to herein also as a
"pre-catalyst", and the activator is referred to herein as a
"co-catalyst". A combination of pre-catalyst and an activator is
also referred to herein and in the art as a catalyst system, and
herein also as a ROMP catalyst system.
[0223] By "chemically activating" it is meant that the activation
of a catalyst is made by an addition of a chemical entity (a
chemical additive), e.g., a chemical compound or a chemical species
such as an ion.
[0224] According to some of these embodiments, the pre-catalyst is
inactive towards initiation of ROMP of the monomer, as defined
herein, in the absence of a respective activator.
[0225] According to these embodiments, a condition for initiating
ROMP of a monomer requires a contact between the pre-catalyst and
the activator and the catalyst and the ROMP monomer.
[0226] In some of these embodiments, the activator is an
activatable activator, which is rendered active towards chemically
activating the catalyst when exposed to a certain condition. In
such cases, the activator is incapable of chemically activating the
catalyst unless it is activated (by exposure to the condition).
Such activators are also referred to herein as "latent
activators".
[0227] A latent activator is incapable of activating a catalyst for
initiating ROMP of the monomer, and can be converted to an active
activator when exposed to an activating condition (which can be the
ROMP inducing condition as described herein).
[0228] According to some of these embodiments, the activator is
inactive towards chemically activating the catalyst, and the
catalyst is therefore inactive towards initiation of ROMP of the
monomer when the ROMP system is not exposed to the condition that
activates the activator.
[0229] By "inactive towards chemically activating the catalyst" it
is meant that no chemical reaction between the activator and the
catalyst occurs, such that in the ROMP system containing the ROMP
monomer, a ROMP catalyst which is chemically activatable by the
activator, and the latent activator, no more than 40% or no more
than 30% or no more than 20% or no more than 10% or no more than 5%
of the monomer polymerizes via ROMP mechanism to provide a
respective polymer.
[0230] Latent activators as described herein can be
thermally-activatable activators, which are converted into active
activators upon exposure to heat (that is, a condition for inducing
initiation of ROMP comprises heat or heating a ROMP system,
optionally in addition to contacting an activator and a catalyst
and a ROMP monomer).
[0231] Latent activators as described herein can be
photo-activatable catalysts, which are converted into active
activators upon exposure to radiation (that is, a condition for
inducing initiation of ROMP comprises exposure to radiation or
application of radiation to the ROMP system, optionally in addition
to contacting an activator and a catalyst and a catalyst and a ROMP
monomer). The radiation can be, for example, an electromagnetic
radiation (e.g., UV or visible or IR light), or ultrasound
radiation, and can be applied by a suitable source of the
radiation.
[0232] In some of any of the embodiments described herein, a ROMP
system can further comprise a ROMP inhibitor.
[0233] A "ROMP inhibitor" as used herein refers to a material that
slows down a ROMP reaction initiated by a catalyst. ROMP inhibitors
can be used with active catalysts, latent catalysts and
pre-catalysts, as described herein. In some embodiments, a ROMP
inhibitor inhibits a ROMP reaction initiated in the presence of an
active catalyst, or once a latent catalyst or pre-catalyst is
converted to an active catalyst, by interfering with the chemical
reactions that activate a latent catalyst or a pre-catalyst.
[0234] It is to be noted that a ROMP system as described herein
refers to the active components and/or conditions that together
lead to ROMP polymerization of a ROMP monomer. A formulation that
comprises a ROMP system can further comprise other components which
can participate in polymerization or curing reactions (e.g.,
curable materials or systems), and/or form a part of the final
polymeric material, as described in further detail hereinbelow.
[0235] Herein throughout, whenever a ROMP monomer is indicated, it
is to be understood as encompassing one or more (e.g., a mixture of
two, three or more) ROMP monomer(s); whenever a ROMP catalyst or
pre-catalyst is indicated, it is to be understood as encompassing
one or more (e.g., a mixture of two, three or more)
pre-catalyst(s); whenever a ROMP activator is indicated, it is to
be understood as encompassing one or more (e.g., a mixture of two,
three or more) ROMP activator(s); whenever a ROMP inhibitor is
indicated, it is to be understood as encompassing one or more
(e.g., a mixture of two, three or more) ROMP inhibitor(s); and
whenever a toughening agent (e.g., an impact modifying agent) is
indicated, it is to be understood as encompassing one or more
(e.g., a mixture of two, three or more) agents. Similarly, whenever
reference to any other agent or moiety is made herein throughout,
it is to be understood as encompassing one or more (e.g., a mixture
of two, three or more) agent(s) or moiety/moieties.
[0236] ROMP Monomers:
[0237] A ROMP monomer as described herein describes any material
that undergoes ROMP in the presence of a ROMP catalyst or a ROMP
catalyst system.
[0238] Typically ROMP monomers are unsaturated cyclic compounds
(cyclic olefins), and preferably strained unsaturated cyclic
compounds (strained cyclic olefins).
[0239] Any compound that can undergo ROMP is encompassed by the
present embodiments.
[0240] The phrase "ROMP monomer" as used herein encompasses one
ROMP monomer or a combination of ROMP monomers, and also
encompasses a mixture of a ROMP monomer with another cyclic olefin
that can react with a ROMP monomer during ROMP of the ROMP monomer,
if included in the same reaction mixture. Such cyclic olefins can
be recognized by those skilled in the art.
[0241] Exemplary ROMP monomers include, but are not limited to
dicyclopentadiene (DCPD), cyclopentadiene trimer, tetramer,
pentamer, etc., norbornene, cyclooctene, cyclooctadiene,
cyclobutene, cyclopropene and substituted derivatives thereof, for
example, substituted norbornenes such as carboxylated norbornenes,
butyl norbornene, hexyl norbornene, octyl norbornene.
[0242] Any cyclic olefin (unsaturated cyclic compounds) suitable
for the metathesis reactions disclosed herein may be used.
[0243] Herein, the phrases "cyclic olefin" and "unsaturated cyclic
compound" are used interchangeably encompasses compounds comprising
one, two, three or more non-aromatic rings (fused and/or unfused
rings) which comprise at least one pair of adjacent carbon atoms in
the ring which are bound to one another by an unsaturated bond. The
ring may optionally be substituted or unsubstituted, and the cyclic
olefin may optionally comprise one unsaturated bond
("monounsaturated"), two unsaturated bonds ("di-unsaturated"),
three unsaturated bond ("tri-unsaturated"), or more than three
unsaturated bonds. When substituted, any number of substituents may
be present (optionally from 1 to 5, and optionally 2, 3, 4 or 5
substituents), and the substituent(s) may optionally be any
substituent describes herein as being optionally attached to an
alkyl or alkenyl.
[0244] Examples of cyclic olefins include, without limitation,
cyclooctene, cyclododecene, and
(c,t,t)-1,5,9-cyclododecatriene.
[0245] Examples of cyclic olefins with more than one ring include,
without limitation, norbornene, dicyclopentadiene,
tricyclopentadiene, and 5-ethylidene-2-norbornene.
[0246] The cyclic olefin may be a strained or unstrained cyclic
olefin, provided the cyclic olefin is able to participate in a ROMP
reaction either individually or as part of a ROMP cyclic olefin
composition. While certain unstrained cyclic olefins such as
cyclohexene are generally understood to not undergo ROMP reactions
by themselves, under appropriate circumstances, such unstrained
cyclic olefins may nonetheless be ROMP active. For example, when
present as a co-monomer in a ROMP composition, unstrained cyclic
olefins may be ROMP active. Accordingly, as used herein and as
would be appreciated by the skilled artisan, the term "unstrained
cyclic olefin" is intended to refer to those unstrained cyclic
olefins that may undergo a ROMP reaction under any conditions, or
in any ROMP composition, provided the unstrained cyclic olefin is
ROMP active.
[0247] In some embodiments of any one of the embodiments described
herein, the substituted or unsubstituted cyclic olefin comprises
from 5 to 24 carbon atoms. In some such embodiments, the cyclic
olefin is a hydrocarbon devoid of heteroatoms. In alternative
embodiments, the cyclic olefin comprises one or more (e.g., from 2
to 12) heteroatoms such as O, N, S, or P, for example, crown ether
cyclic olefins which include numerous O heteroatoms throughout the
cycle, are within the scope of the invention.
[0248] In some embodiments of any one of the embodiments described
herein relating to a cyclic olefin comprising from 5 to 24 carbon
atoms, the cyclic olefin is monounsaturated, di-unsaturated, or
tri-unsaturated.
[0249] In some embodiments of any of the embodiments described
herein, the cyclic olefin has the general formula (A):
##STR00001##
wherein:
[0250] R.sup.A1 and R.sup.A2 are each independently hydrogen,
alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl,
heteroalicyclic, halo, hydroxy, alkoxy, aryloxy, thiohydroxy,
thioalkoxy, thioaryloxy, sulfinyl, sulfonyl, sulfonate, nitrile,
nitro, azide, phosphonyl, phosphinyl, oxo, carbonyl, thiocarbonyl,
urea, thiourea, carbamyl, N-carbamyl, O-thiocarbamyl,
N-thiocarbamyl, C-amido, N-amido, C-carboxy, O-carboxy,
sulfonamido, and amino;
[0251] J is a saturated or unsaturated hydrocarbon, which may be
substituted or unsubstituted, and may optionally comprise one or
more heteroatoms between the carbon atoms thereof. Additionally,
two or more substituents attached to ring atoms within J may
optionally be linked to form a bicyclic or polycyclic olefin.
[0252] In some embodiments of any of the respective embodiments
described herein, the compound of formula (A) contains from 5 to 14
ring atoms, optionally from 5 to 8 ring atoms, for a monocyclic
olefin; and, for bicyclic and polycyclic olefins, from 4 to 8 ring
atoms in each ring, optionally from 5 to 7 ring atoms in each
ring.
[0253] In some embodiments of any of the embodiments described
herein, the cyclic olefin has the general formula (B):
##STR00002##
wherein:
[0254] b is an integer in a range of 1 to 10, optionally 1 to
5;
[0255] R.sup.A1 and R.sup.A2 are as defined above for formula (A);
and
[0256] R.sup.B1, R.sup.B2, R.sup.B3, R.sup.B4, R.sup.B5, and
R.sup.B6 are each independently hydrogen, alkyl, cycloalkyl,
alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic, halo, hydroxy,
alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, sulfinyl,
sulfonyl, sulfonate, nitrile, nitro, azide, phosphonyl, phosphinyl,
oxo, carbonyl, thiocarbonyl, urea, thiourea, carbamyl, N-carbamyl,
O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, C-carboxy,
O-carboxy, sulfonamido, and amino, or alternatively, any of the
R.sup.B1, R.sup.B2, R.sup.B3, R.sup.B4, R.sup.B5, and R.sup.B6
moieties can be linked to any of the other R.sup.B1, R.sup.B2,
R.sup.B3, R.sup.B4, R.sup.B5, and R.sup.B6 moieties to provide a
substituted or unsubstituted 4- to 7-membered ring;
[0257] In some embodiments of any of the embodiments described
herein, the cyclic olefin is monocyclic.
[0258] In some embodiments of any of the embodiments described
herein, the cyclic olefin is monounsaturated, optionally being both
monocyclic and monounsaturated.
[0259] Examples of monounsaturated, monocyclic olefins encompassed
by formula (B) include, without limitation, cyclopentene,
cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene,
cycloundecene, cyclododecene, tricyclodecene, tetracyclodecene,
octacyclodecene, and cycloeicosene, and substituted versions
thereof such as methylcyclopentene (e.g., 1-methylcyclopentene,
4-methylcyclopentene), ethylcyclopentene (e.g 1-ethylcyclopentene),
isopropylcyclohexene (e.g., 1-isopropylcyclohexene), chloropentene
(e.g., 1-chloropentene), fluorocyclopentene (e.g.,
1-fluorocyclopentene), methoxycyclopentene (e.g.,
4-methoxy-cyclopentene), ethoxycyclopentene (e.g.,
4-ethoxy-cyclopentene), cyclopentene-thiol (e.g.,
cyclopent-3-ene-thiol), methylsulfanyl-cyclopentene (e.g.,
4-methylsulfanyl-cyclopentene), methylcyclohexene (e.g.,
3-methylcyclohexene), methylcyclooctene (e.g.,
1-methylcyclooctene), and dimethylcyclooctene (e.g.,
1,5-dimethylcyclooctene).
[0260] In some embodiments of any of the embodiments described
herein, the cyclic olefin is diunsaturated, optionally being both
monocyclic and diunsaturated.
[0261] In some embodiments, the cyclic olefin has the general
formula (C):
##STR00003##
wherein:
[0262] c and d are each independently integers in the range of from
1 to 8, optionally from 2 to 4, and optionally 2 (such that the
cyclic olefin is a cyclooctadiene);
[0263] R.sub.A1 and R.sup.A2 are as defined above for formula (A);
and R.sup.C1, R.sup.C2, R.sup.C3, R.sup.C4, R.sup.C5, and R.sup.C6
are each independently defined as for R.sup.B1-R.sup.B6.
[0264] In some embodiments, R.sup.C3 and R.sup.C4 are substituents
(i.e., not hydrogen), in which case at least one of the olefinic
moieties is tetrasubstituted.
[0265] Examples of diunsaturated, monocyclic olefins include,
without limitation, 1,3-cyclopentadiene, 1,3-cyclohexadiene,
1,4-cyclohexadiene, heptadiene (e.g., 1,3-cycloheptadiene),
octadiene (e.g., 1,5-cyclooctadiene, 1,3-cyclooctadiene), and
substituted versions thereof (e.g.,
5-ethyl-1,3-cyclohexadiene).
[0266] In some embodiments of any of the embodiments described
herein, the cyclic olefin comprises more than two (optionally
three) unsaturated bonds. In some embodiments, such compounds are
analogous to the diene structure of formula (C), comprising at
least one methylene linkage (analogous to the number of methylene
linkages indicated by the variables c and d in formula (C)) between
any two olefinic segments.
[0267] In some embodiments of any of the embodiments described
herein, the cyclic olefin is polycyclic.
[0268] Herein, the term "polycyclic" refers to a structure
comprising two or more fused rings.
[0269] In some embodiments of any of the embodiments described
herein, the cyclic olefin is a polycyclic olefin having the general
formula (D):
##STR00004##
wherein:
[0270] R.sup.A1 and R.sup.A2 are each independently as defined
above for formula (A);
[0271] R.sup.D1, R.sup.D2, R.sup.D3 and R.sup.D4 are each
independently as defined for R.sup.B1-R.sup.B6;
[0272] e is an integer in the range of from 1 to 8, optionally from
2 to 4;
[0273] f is 1 or 2; and
[0274] T is a substituted or unsubstituted saturated or unsaturated
hydrocarbon of 1-4 carbon atoms in length (optionally 1 or 2 carbon
atoms in length, for example, substituted or unsubstituted methyl
or ethyl), O, S, N(R.sup.G1), P(R.sup.G1), P(.dbd.O)(R.sup.G1),
Si(R.sup.G1).sub.2, B(R.sup.G1), or As(R.sup.G1), wherein R.sup.G1
is alkyl, alkenyl, alkynyl, cycloalkyl, heteroalicyclic, aryl,
heteroaryl, alkoxy or aryloxy.
[0275] Cyclic olefins encompassed by formula (D) are examples of
compounds in the norbornene family.
[0276] As used herein, the term "norbornene" refers to any compound
that includes at least one substituted or unsubstituted
bicyclo[2.2.1]hept-2-ene moiety or dehydrogenated derivative
thereof, including without limitation, bicyclo[2.2.1]hept-2-ene
(referred to in the art as "norbornene") and substituted versions
thereof, norbornadiene, (bicyclo[2.2.1]hepta-2,5-diene) and
substituted versions thereof, and polycyclic norbornenes, and
substituted versions thereof.
[0277] In some embodiments, the cyclic olefin is a polycyclic
norbornene having the general formula (E):
##STR00005##
wherein:
[0278] R.sup.A1 and R.sup.A2 are each independently as defined
above for formula (A);
[0279] T is as defined above for formula (D);
[0280] R.sup.E1, R.sup.E2, R.sup.E3, R.sup.E4, R.sup.E5, R.sup.E6,
R.sup.E7, and R.sup.E8 are each independently as defined for
R.sup.B1-R.sup.B6; and
[0281] "a" represents a saturated bond or unsaturated double bond,
wherein when "a" is an unsaturated double bond, one of R.sup.E5,
R.sup.E6 and one of R.sup.E7, R.sup.E8 is absent;
[0282] f is 1 or 2; and
[0283] g is an integer from 0 to 5.
[0284] In some embodiments, the cyclic olefin has the general
formula (F):
##STR00006##
wherein:
[0285] R.sup.F1, R.sup.F2, R.sup.F3 and R.sup.F4 defined above for
R.sup.E4, R.sup.E5, R.sup.E6, R.sup.E7, and R.sup.E8
respectively;
[0286] and
[0287] a and g are as defined in formula (E) hereinabove.
[0288] Examples of bicyclic and polycyclic olefins include, without
limitation, dicyclopentadiene (DCPD); trimer and higher order
oligomers of cyclopentadiene (e.g., cyclopentadiene tetramer,
cyclopentadiene pentamer); ethylidenenorbornene; dicyclohexadiene;
norbornene; 5-methyl-2-norbornene; 5-ethyl-2-norbornene;
5-isobutyl-2-norbornene; 5,6-dimethyl-2-norbornene;
5-phenylnorbornene; 5-benzylnorbornene; 5-acetylnorbornene;
5-methoxycarbonylnorbornene; 5-ethyoxycarbonyl-1-norbornene;
5-methyl-5-methoxy-carbonylnorbornene; 5-cyanonorbornene;
5,5,6-trimethyl-2-norbornene; cyclo-hexenylnorbornene;
endo,exo-5,6-dimethoxynorbornene;
endo,endo-5,6-dimethoxynorbornene;
endo,exo-5,6-dimethoxycarbonylnorbornene;
endo,endo-5,6-dimethoxycarbonylnorbornene; 2,3-dimethoxynorbornene;
norbornadiene; tricycloundecene; tetracyclododecene;
8-methyltetracyclododecene; 8-ethyltetracyclododecene;
8-methoxycarbonyltetracyclododecene; 8-methyl-8-tetracyclododecene;
8-cyanotetracyclododecene; pentacyclopentadecene;
pentacyclohexadecene; and the like, and their structural isomers,
stereoisomers, and mixtures thereof.
[0289] Additional examples of bicyclic and polycyclic olefins
include, without limitation, C.sub.2-C.sub.12-alkyl-substituted and
C.sub.2-C.sub.12-alkenyl-substituted norbornenes, for example,
5-butyl-2-norbornene, 5-hexyl-2-norbornene, 5-octyl-2-norbornene,
5-decyl-2-norbornene, 5-dodecyl-2-norbornene, 5-vinyl-2-norbornene,
5-ethylidene-2-norbornene, 5-isopropenyl-2-norbornene,
5-propenyl-2-norbornene, and 5-butenyl-2-norbornene, and the
like.
[0290] In some embodiments of any of the embodiments described
herein, the cyclic olefin is dicyclopentadiene; tricyclopentadiene;
dicyclohexadiene; norbornene; 5-methyl-2-norbornene;
5-ethyl-2-norbornene; 5-isobutyl-2-norbornene;
5,6-dimethyl-2-norbornene; 5-phenylnorbornene; 5-benzylnorbornene;
5-acetylnorbornene; 5-methoxycarbonylnorbornene;
5-ethoxycarbonyl-1-norbornene;
5-methyl-5-methoxy-carbonylnorbornene; 5-cyanonorbornene;
5,5,6-trimethyl-2-norbornene; cyclo-hexenylnorbornene;
endo,exo-5,6-dimethoxynorbornene;
endo,endo-5,6-dimethoxynorbornene;
endo,exo-5-6-dimethoxycarbonylnorbornene;
endo,endo-5,6-dimethoxycarbonylnorbornene; 2,3-dimethoxynorbornene;
norbornadiene; tricycloundecene; tetracyclododecene;
8-methyltetracyclododecene; 8-ethyltetracyclododecene;
8-methoxycarbonyltetracyclododecene; 8-methyl-8-tetracyclododecene;
8-cyanotetracyclododecene; pentacyclopentadecene;
pentacyclohexadecene; an oligomer of cyclopentadiene (e.g.,
cyclopentadiene tetramer, cyclopentadiene pentamer); and/or a
C.sub.2-C.sub.12-alkyl-substituted norbornene or
C.sub.2-C.sub.12-alkenyl-substituted norbornene (e.g.,
5-butyl-2-norbornene; 5-hexyl-2-norbornene; 5-octyl-2-norbornene;
5-decyl-2-norbornene; 5-dodecyl-2-norbornene; 5-vinyl-2-norbornene;
5-ethylidene-2-norbornene; 5-isopropenyl-2-norbornene;
5-propenyl-2-norbornene; 5-butenyl-2-norbornene).
[0291] In some embodiments of any of the embodiments described
herein, the cyclic olefin is dicyclopentadiene, tricyclopentadiene,
or higher order oligomer of cyclopentadiene (e.g., cyclopentadiene
tetramer, cyclopentadiene pentamer), tetracyclododecene,
norbornene, and/or a C.sub.2-C.sub.12-alkyl-substituted norbornene
or C.sub.2-C.sub.12-alkenyl-substituted norbornene (e.g., according
to any of the respective embodiments described herein).
[0292] Additional examples for ROMP capable cyclic olefin monomers
which may be optionally used in embodiments of the invention
include any polycyclic compounds which are characterized by the
presence of at least two norbornene moieties in its structure, for
example:
##STR00007##
[0293] In some embodiments of any of the embodiments described
herein, the cyclic olefin is characterized by the presence of at
least three rings.
[0294] In some embodiments of any of the embodiments described
herein relating to a norbornene-based monomer, a monocyclic olefin
(e.g., cyclobutene, cyclopentene, cyclopentadiene, cyclooctene,
cyclododecene) is copolymerized with the norbornene-based
monomer.
[0295] Without being bound by any particular theory, it is believed
that polycyclic monomers with a rigid backbone, such as
cyclopentadiene trimer (TCPD or CPD trimer) will typically produce
a cross-linked polymer with very high Tg and heat deflection
temperature (HDT), but will also be more brittle and may have lower
impact resistance.
[0296] In some embodiments of any of the embodiments described
herein, a polycyclic monomer with a rigid backbone (e.g., according
to any of the respective embodiments described herein) is
formulated with one or more softer additional monomers and/or cross
linkers.
[0297] Examples of additional monomers include, without limitation,
monomers having the formula:
##STR00008##
[0298] wherein Rx and Ry are each independently hydrogen,
C.sub.1-C.sub.20-alkyl, cycloalkyl, heteroalicyclic, aryl,
polyethylene glycol, polypropylene glycol or benzyl.
[0299] Example of bifunctional cyclic olefins, which may also act
as cross linkers include, without limitation, compounds having any
one of the following formulas:
##STR00009##
[0300] wherein Rx and Ry are each independently hydrogen,
C.sub.1-C.sub.20-alkyl, cycloalkyl, heteroalicyclic, aryl,
polyethylene glycol, polypropylene glycol or benzyl; and
[0301] K.sub.1 and K.sub.2 are each independently
C.sub.1-C.sub.20-alkylene, cycloalkyl, heteroalicyclic, aryl,
polyethylene glycol, polypropylene glycol or benzyl.
[0302] Additional examples of bifunctional cyclic olefins include,
without limitation:
##STR00010##
[0303] The connection between an additional monomer and/or
bifunctional monomer (cross-linker) to a polycyclic (e.g.,
norbornene) monomer may optionally be, without limitation, through
a saturated or unsaturated carbon-carbon bond, an ester bond, and
ether bond, an amine, or an amide bond.
[0304] Synthesis of norbornene derivatives described herein
according to any of the respective embodiments may optionally be
performed by Diels-Alder reaction of double bond with
cyclopentadiene (CPD), as depicted in Scheme 1 below:
##STR00011##
[0305] Substituents of a polymerized cyclic olefin may optionally
be in a protected form in the monomer. For example, hydroxy groups,
which may interfere with metathesis catalysis, may be protected by
being in a form of any suitable protected group used in the art.
Acceptable protecting groups may be found, for example, in Greene
et al., Protective Groups in Organic Synthesis, 3rd Ed. (New York:
Wiley, 1999).
[0306] In a preferred embodiment, the ROMP monomer is or comprises
DCPD due to its high reactivity, and the high thermal resistance
and toughness properties exhibited by a printed object made
therefrom.
[0307] In a preferred embodiment, the ROMP monomer is or comprises
a CPD trimer due to its suitable viscosity and the high thermal
resistance exhibited by a printed object made therefrom.
[0308] In a preferred embodiment, a ROMP monomer is or comprises a
mixture of DCPD and CPD trimer, for example, a mixture known in the
art, and also referred to herein as "RIM monomer". In some
embodiments, such a mixture comprises DCPD at a concentration
ranging from about 70% to about 99%, or from 85% to about 95%, by
weight, of the total weight of a ROMP monomer, and a CPD trimer at
a concentration ranging from about 30% to about 1%, or from about
15% to about 5%, respectively, by weight, of the total weight of a
ROMP monomer.
[0309] In a commercially available "RIM monomer", a concentration
of DCPD is typically from about 90% to about 92%.
[0310] In some embodiments, a ROMP monomer is or comprises about
91% DCPD and about 9% CPD trimer, as described herein.
[0311] Table A below presents non-limiting examples of suitable
ROMP polymerizable monomers according to some embodiments of the
present invention.
TABLE-US-00001 TABLE A Trade name Structure Supplier DCPD
Dicyclopentadiene Telene SAS RIM monomer Cyclopentadiene trimer in
Telene SAS dicyclopentadiene Cyclopentadiene trimer Cyclopentadiene
trimer Zeon Cyclooctene Cyclooctene Sigma Aldrich Cyclooctadiene
Cyclooctadiene Sigma Aldrich Norbornene Norbornene Sigma Aldrich
ENB 5-Ethylidene-2-norbornene Sigma Aldrich cyclododecatriene
cyclododecatriene BASF
[0312] ROMP Catalysts and Catalyst Systems:
[0313] ROMP catalysts typically include metal carbene
organometallic complexes, with the metal being typically, but not
necessarily, a transition metal such as ruthenium, molybdenum,
osmium or tungsten.
[0314] Ruthenium based ROMP catalysts are more stable on exposure
to non carbon-carbon double-bond functional groups, and to other
impurities like water and oxygen. These catalysts can typically be
used in low loading in the formulation (e.g., in a range of from
about 0.002% to about 0.05% by weight of the total weight of a
modeling material formulation containing same).
[0315] Ruthenium based ROMP catalysts that are usable in the
context of embodiments of the present invention are marketed, for
example, by Materia, Umicore, Evonic, Telene and BASF.
[0316] Exemplary ruthenium-based ROMP catalysts include, Grubbs
1.sup.st and 2.sup.nd generation catalysts, Hoveyda-Grubbs
catalysts, umicore 41, umicore 42, umicore 61SIMes, and catMETium
RF1.
[0317] ROMP catalysts can be divided into active catalysts, latent
catalysts and pre-catalysts.
[0318] An active catalyst is a ROMP catalyst that initiates ROMP of
a monomer when in contact with the ROMP monomer, without requiring
a stimulus. ROMP active catalysts are typically active at room
temperature.
[0319] Exemplary active catalysts usable in the context of the
present embodiments are the Grubbs 2.sup.nd generation,
Hoveyda-Grubbs 2.sup.nd generation, and Grubbs 3.sup.rd generation
catalysts, which are realized by any person skilled in the art.
[0320] A latent catalyst is a ROMP catalyst that initiates ROMP of
a monomer when in contact with the ROMP monomer, upon exposure to a
physical stimulus, typically heat or radiation, as described
herein. A latent catalyst is inactive in initiating ROMP of a
monomer in the absence of a suitable physical stimulus.
[0321] A latent catalyst typically includes a chelating (e.g.,
donor) ligand which "blocks" a coordinative site of the metal and
thus renders the catalyst inactive. Activating the catalyst is
effected by dissociating the chelating ligand from the metal
center, to thereby render it active towards metathesis.
[0322] In a latent catalyst, dissociating the chelating ligand
requires a physical external stimulus, as described herein. The
type of the external stimulus is determined by the nature of the
metal, the chelating ligand and other ligands in the transition
metal complex.
[0323] Latent ROMP catalysts that are activated in response to heat
are also referred to as thermally-activatable catalysts. These
include, for example, S-chelated ruthenium catalysts such as
described, for example, in Diesendruck, C. E.; Vidaysky, Y.;
Ben-Asuly, A.; Lemcoff, N. G., J. Polym. Sci., Part A: Polym. Chem.
2009, 47, 4209-4213, which is incorporated by reference as if fully
set forth herein.
[0324] An exemplary S-chelated thermally-activatable latent
catalyst is:
##STR00012##
[0325] Other exemplary thermally-activatable ROMP catalysts include
N-chelated ruthenium catalysts, such as, for example, described in
Szadkowska et al., Organometallics 2010, 29, 117-124, which is
incorporated by reference as if fully set forth herein.
[0326] Exemplary N-chelated thermally-activatable latent catalyst
include, without limitation:
##STR00013##
[0327] Any other thermally-activatable ROMP catalysts are
contemplated.
[0328] Latent ROMP catalysts that are activated in response to
radiation are also referred to as photoactivatable catalysts.
[0329] Photoactivatable ROMP catalysts are mostly UV-activatable
catalysts, in which dissociation of a chelating ligand is effected
in the presence of UV radiation. Exemplary UV-activatable ROMP
latent catalysts are described, for example, in Vidaysky, Y. and
Lemcoff, N. G. Beilstein J. Org. Chem., 2010, 6, 1106-1119;
Ben-Asuly et al., Organometallics, 2009, 28, 4652-4655; Diesendruck
et al., J. Polym. Sci., Part A: Polym. Chem. 2009, 47, 4209-4213;
Wang et al., Angew. Chem. Int. Ed. 2008, 47, 3267-3270; and U.S.
Patent Application Publication No. 2009-0156766, all of which are
incorporated by reference as if fully set forth herein.
[0330] UV-activatable ROMP catalysts can be, for example,
O-chelated and S-chelated Ruthenium catalysts.
[0331] Non-limiting examples include the following:
##STR00014##
with R being Ph, beta-Naph, 1-Pyrenyl, or i-Pr;
[0332] and all catalysts described in Vidaysky, Y. and Lemcoff, N.
G. Beilstein J. Org. Chem., 2010, 6, 1106-1119.
[0333] UV-activatable ROMP catalysts can be, for example, tungsten
catalysts such as, for example:
##STR00015##
[0334] Photoactivatable latent catalyst can also be activated in
response to ultrasound radiation. Such catalysts are described, for
example, in Piermattei et al., Nature Chemistry, DOI:
10.1038/NCHEM.167, which is incorporated by reference as if fully
set forth herein.
[0335] A ROMP pre-catalyst is a ROMP catalyst that initiates ROMP
of a monomer when in contact with the ROMP monomer, upon exposure
to a chemical stimulus, as described herein, typically an addition
of an acid or a proton, which converts the pre-catalyst to an
active catalyst (which induces ROMP of a ROMP monomer when in
contact with the ROMP monomer). A pre-catalyst is inactive in
initiating ROMP of a monomer in the absence of the chemical
stimulus.
[0336] A pre-catalyst, similarly to a latent catalyst, typically
includes a chelating (e.g., donor) ligand which "blocks" a
coordinative site of the metal and thus renders the catalyst
inactive. Activating the catalyst is effected by dissociating the
chelating ligand from the metal center, to thereby render it active
towards metathesis.
[0337] In a pre-catalyst, dissociating the chelating ligand
requires a chemical stimulus, typically a presence of an acid. The
agent that exerts a chemical stimulus that activates the catalyst
is referred to herein as an activator or a co-catalyst.
[0338] A ROMP pre-catalyst and a suitable activator form together a
catalyst system.
[0339] The activator can be, for example, an acid, such as HCl, an
acid generator such as, but not limited to, (R.sub.nSiCl.sub.4-n),
with R being an alkyl or aryl, and n being 1, 2, or 3, or an acid
generator as described, for example, in EP Patent No. 1757613 and
U.S. Pat. No. 8,519,069, the teachings of which are incorporated by
reference as if fully set forth herein. In some embodiments, when n
is 2 or 3, one or the R groups can be hydrogen, and the R groups
can be the same or different, as long as at least one of the R
groups is an alkyl or aryl. Exemplary activators are presented in
Table B below.
TABLE-US-00002 TABLE B Trade name Structure Supplier
Trichloro(phenyl)silane ##STR00016## Sigma Aldrich Acid activator
HCl Sigma Acid Aldrich activator Chlorophenylsilane ##STR00017##
Sigma Aldrich Acid activator Dichloro(phenyl)silane ##STR00018##
Sigma Aldrich Acid activator Dichloromethyl(phenyl)silane
##STR00019## Sigma Aldrich Acid activator ChloroDimethyl Phenyl
Silane ##STR00020## Sigma Aldrich Acid activator
ChloroTrimethylSilane ##STR00021## TCI Acid activator
Butyl(chloro)dimethyl Silane, ##STR00022## TCI Acid activator
Chloro-decyl-dimethyl Silane ##STR00023## TCI Acid activator
Chloro(chloromethyl)dimethyl ##STR00024## TCI Acid activator
Chloro(dichloromethyl) dimethylsilane ##STR00025## Alfa Aesar Acid
activator Pentafluoropropionic acid ##STR00026## Sigma Non chloride
Acid activator Trifluoroacetic acid ##STR00027## Sigma Non chloride
Acid activator Trichloroacetic acid ##STR00028## Sigma Acid
activator Trichlorododecyl silane (TCSA) ##STR00029## Sigma-
Aldrich Acid activator Trichloro(octadecyl) silane
CH.sub.3(CH.sub.2).sub.16CH.sub.2SiCl.sub.3 Sigma- Acid Aldrich
activator Dichlorodiphenyl silane ##STR00030## Sigma- Aldrich Acid
activator Perfluoro decyldimethylchloro silane ##STR00031## Acros
Acid activator Perfluoro decylmethyl dichlorosilane ##STR00032##
Acros Acid activator
[0340] Alternatively, the activator is activatable in response to
an external stimulus, for example, heat or radiation.
[0341] A group of latent activators which are usable in the context
of the present embodiments is known in the art as photoacid
generators (PAG). Such activators and corresponding pre-catalysts
are described for example, in Keitz, B. K.; Grubbs, R. H. J. Am.
Chem. Soc. 2009, 131, 2038-2039, which is incorporated by reference
as if fully set forth herein.
[0342] Additional exemplary PAG include sulfonium salts such as
triaryl sulfonium chloride and UVI 6976, iodonium salt Uvacure
1600, Speedcure 937, Irgacure 250, Irgacure PAG 103, Irgacure PAG
203, 2-(4-Methoxystyryl)-4,6-bis(trichloromethyl)-1,3,5-triazine
and TMCH. Other exemplary commercially available PAG are described
in Table 1 hereinunder.
[0343] Acid-activatable ROMP catalysts are described, for example,
in U.S. Pat. No. 6,486,279. Other catalysts that can be activated
by PAG are acid activatable pre-catalysts such as the Schiff
base-chelated catalysts described in EP Patent No. 1757613 and U.S.
Pat. No. 8,519,069.
[0344] Other ROMP catalyst systems are recognizable by any person
skilled in the art.
[0345] Additional exemplary ROMP catalysts usable in the context of
the present embodiments are described in WO 2014/144634, which is
incorporated by reference as if fully set forth herein.
[0346] In some embodiments, a ROMP catalyst can be represented by
the following Formula:
##STR00033##
wherein, M is a Group 8 transition metal, particularly Ru or Os,
or, more preferably, Ru (ruthenium); X.sup.1, X.sup.2, and L.sup.1
are neutral ligands commonly used for olefin metathesis catalyst,
particularly Ru-based catalyst; Y is a heteroatom selected from N,
O, S, and P; preferably Y is O or N; R.sup.5, R.sup.6, R.sup.7, and
R.sup.8 are each, independently, selected from the group consisting
of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, heteroalkyl,
heteroatom containing alkenyl, heteroalkenyl, heteroaryl, alkoxy,
alkenyloxy, aryloxy, alkoxycarbonyl, carbonyl, alkylamino,
alkylthio, aminosulfonyl, monoalkylaminosulfonyl,
dialkylaminosulfonyl, alkylsulfonyl, nitrile, nitro, alkylsulfinyl,
trihaloalkyl, perfluoroalkyl, carboxylic acid, ketone, aldehyde,
nitrate, cyano, isocyanate, hydroxyl, ester, ether, amine, imine,
amide, halogen-substituted amide, trifluoroamide, sulfide,
disulfide, sulfonate, carbamate, silane, siloxane, phosphine,
phosphate, borate, or -A-Fn, wherein "A" and Fn have been defined
above; and any combination of Y, Z, R.sup.5, R.sup.6, R.sup.7, and
R.sup.8 can be linked to form one or more cyclic groups; n is 0, 1,
or 2, such that n is 1 for the divalent heteroatoms O or S, and n
is 2 for the trivalent heteroatoms N or P; and Z is a group
selected from hydrogen, alkyl, aryl, functionalized alkyl,
functionalized aryl where the functional group(s) may independently
be one or more of the following: alkoxy, aryloxy, halogen,
carboxylic acid, ketone, aldehyde, nitrate, cyano, isocyanate,
hydroxyl, ester, ether, amine, imine, amide, trifluoroamide,
sulfide, disulfide, carbamate, silane, siloxane, phosphine,
phosphate, or borate; methyl, isopropyl, sec-butyl, t-butyl,
neopentyl, benzyl, phenyl and trimethylsilyl; and wherein any
combination or combinations of X.sup.1, X.sup.2, L.sup.1, Y, Z,
R.sup.5, R.sup.6, R.sup.7, and R.sup.8 may be linked to a support.
Additionally, R.sup.5, R.sup.6, R.sup.7, R.sup.8, and Z may
independently be thioisocyanate, cyanato, or thiocyanato.
[0347] Additional exemplary ROMP catalysts can be represented by
the following formula:
##STR00034##
[0348] wherein M is a Group 8 transition metal, particularly
ruthenium or osmium, or more particularly, ruthenium;
[0349] X.sup.1, X.sup.2, L.sup.1, and L.sup.2 are common ligands of
catalysts as defined above; and
[0350] R.sup.G1, R.sup.G2, R.sup.G3, R.sup.G4, R.sup.G5, and
R.sup.G6 are each independently selected from the group consisting
of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, heteroalkyl,
heteroatom containing alkenyl, heteroalkenyl, heteroaryl, alkoxy,
alkenyloxy, aryloxy, alkoxycarbonyl, carbonyl, alkylamino,
alkylthio, aminosulfonyl, monoalkylaminosulfonyl,
dialkylaminosulfonyl, alkylsulfonyl, nitrile, nitro, alkylsulfinyl,
trihaloalkyl, perfluoroalkyl, carboxylic acid, ketone, aldehyde,
nitrate, cyano, isocyanate, thioisocyanate, cyanato, thiocyanato,
hydroxyl, ester, ether, thioether, amine, alkylamine, imine, amide,
halogen-substituted amide, trifluoroamide, sulfide, disulfide,
sulfonate, carbamate, silane, siloxane, phosphine, phosphate,
borate, or -A-Fn, wherein "A" is a divalent hydrocarbon moiety
selected from alkylene and arylalkylene, wherein the alkyl portion
of the alkylene and arylalkylene groups can be linear or branched,
saturated or unsaturated, cyclic or acyclic, and substituted or
unsubstituted, wherein the aryl portion of the arylalkylene can be
substituted or unsubstituted, and wherein heteroatoms and/or
functional groups may be present in either the aryl or the alkyl
portions of the alkylene and arylalkylene groups, and Fn is a
functional group, or any one or more of the R.sup.G1, R.sup.G2,
R.sup.G3, R.sup.G4, R.sup.G5, and R.sup.G6 may be linked together
to form a cyclic group.
[0351] Additional ROMP catalysts can be represented by the
following formula:
##STR00035##
[0352] wherein M is a Group 8 transition metal, particularly
ruthenium or osmium, or more particularly, ruthenium;
[0353] X.sup.1 and L.sup.1 are common ligands as defined above;
[0354] Z is selected from the group consisting of oxygen, sulfur,
selenium, NR.sup.JU, PR.sup.JU, AsR.sup.JU, and SbR.sup.JU; and
[0355] R.sup.J1, R.sup.J2, R.sup.J3, R.sup.J4, R.sup.J5, R.sup.J6,
R.sup.J7, R.sup.J8, R.sup.J9, R.sup.J10, and R.sup.J11 are each
independently selected from the group consisting of hydrogen,
halogen, alkyl, alkenyl, alkynyl, aryl, heteroalkyl, heteroatom
containing alkenyl, heteroalkenyl, heteroaryl, alkoxy, alkenyloxy,
aryloxy, alkoxycarbonyl, carbonyl, alkylamino, alkylthio,
aminosulfonyl, monoalkylaminosulfonyl, dialkylaminosulfonyl,
alkylsulfonyl, nitrile, nitro, alkylsulfinyl, trihaloalkyl,
perfluoroalkyl, carboxylic acid, ketone, aldehyde, nitrate, cyano,
isocyanate, thioisocyanate, cyanato, thiocyanato, hydroxyl, ester,
ether, thioether, amine, alkylamine, imine, amide,
halogen-substituted amide, trifluoroamide, sulfide, disulfide,
sulfonate, carbamate, silane, siloxane, phosphine, phosphate,
borate, or -A-Fn, wherein "A" is a divalent hydrocarbon moiety
selected from alkylene and arylalkylene, wherein the alkyl portion
of the alkylene and arylalkylene groups can be linear or branched,
saturated or unsaturated, cyclic or acyclic, and substituted or
unsubstituted, wherein the aryl portion of the arylalkylene can be
substituted or unsubstituted, and wherein hetero atoms and/or
functional groups may be present in either the aryl or the alkyl
portions of the alkylene and arylalkylene groups, and Fn is a
functional group, or any one or more of the R.sup.J1, R.sup.J2,
R.sup.J3, R.sup.J4, R.sup.J5, R.sup.J6, R.sup.J7, R.sup.J8,
R.sup.J9, R.sup.J10, and R.sup.J11 may be linked together to form a
cyclic group.
[0356] Additional ROMP catalysts can be represented by the
following formula:
##STR00036##
[0357] wherein M is a Group 8 transition metal, particularly
ruthenium or osmium, or more particularly, ruthenium;
[0358] X.sup.1, L.sup.1, R.sup.1, and R.sup.2 are as commonly used
in ligands of ROMP catalysts;
[0359] Z is selected from the group consisting of oxygen, sulfur,
selenium, NR.sup.K5, PR.sup.K5, AsR.sup.K5, and SbR.sup.K5;
[0360] m is 0, 1, or 2; and R.sup.k1, R.sup.k2, R.sup.k3, R.sup.k4,
and R.sup.k5 are each independently selected from the group
consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl,
heteroalkyl, heteroatom containing alkenyl, heteroalkenyl,
heteroaryl, alkoxy, alkenyloxy, aryloxy, alkoxycarbonyl, carbonyl,
alkylamino, alkylthio, aminosulfonyl, monoalkylaminosulfonyl,
dialkylaminosulfonyl, alkylsulfonyl, nitrile, nitro, alkylsulfinyl,
trihaloalkyl, perfluoroalkyl, carboxylic acid, ketone, aldehyde,
nitrate, cyano, isocyanate, thioisocyanate, cyanato, thiocyanato,
hydroxyl, ester, ether, thioether, amine, alkylamine, imine, amide,
halogen-substituted amide, trifluoroamide, sulfide, disulfide,
sulfonate, carbamate, silane, siloxane, phosphine, phosphate,
borate, or -A-Fn, wherein "A" is a divalent hydrocarbon moiety
selected from alkylene and arylalkylene, wherein the alkyl portion
of the alkylene and arylalkylene groups can be linear or branched,
saturated or unsaturated, cyclic or acyclic, and substituted or
unsubstituted, wherein the aryl portion of the arylalkylene can be
substituted or unsubstituted, and wherein hetero atoms and/or
functional groups may be present in either the aryl or the alkyl
portions of the alkylene and arylalkylene groups, and Fn is a
functional group, or any one or more of the R.sup.K1, R.sup.K2,
R.sup.K3, R.sup.K4, and R.sup.K5 may be linked together to form a
cyclic group.
[0361] Additional ROMP catalysts can be represented by the
following formula:
##STR00037##
wherein:
[0362] M is a Group 8 transition metal;
[0363] L.sup.1 and L.sup.2 are neutral electron donor ligands;
[0364] X.sup.1 and X.sup.2 are anionic ligands; and
[0365] R.sup.1 and R.sup.2 are independently selected from
hydrogen, hydrocarbyl, substituted hydrocarbyl,
heteroatom-containing hydrocarbyl, substituted
heteroatom-containing hydrocarbyl, and functional groups,
[0366] wherein any two or more of X1, X2, L1, L2, R1, and R2 can be
taken together to form a cyclic group, and further wherein any one
or more of X1, X.sup.2, L.sup.1, L.sup.2, R.sup.1, and R2 may be
attached to a support.
[0367] Preferred catalysts contain Ru or Os as the Group 8
transition metal, with Ru particularly preferred.
[0368] The catalysts having the structure of formula (I) are in one
of two groups. In the first group, L.sup.1 and L.sup.2 are
independently selected from phosphine, sulfonated phosphine,
phosphite, phosphinite, phosphonite, arsine, stibine, ether, amine,
amide, imine, sulfoxide, carboxyl, nitrosyl, pyridine, substituted
pyridine, imidazole, substituted imidazole, pyrazine, and
thioether. Exemplary ligands are trisubstituted phosphines. The
first group of catalysts, accordingly, is exemplified by the
ruthenium bisphosphine complex
(PCy.sub.3).sub.2(Cl).sub.2Ru.dbd.CHPh (1)
##STR00038##
[0369] The catalysts of the second group are transition metal
carbene complexes, preferably ruthenium carbene complexes, wherein
L.sup.2 is as defined above and L.sup.1 is a carbene having the
structure of formula (II):
##STR00039##
such that the complex has the structure of formula (IIA):
##STR00040##
wherein:
[0370] X.sup.1, X.sup.2, L.sup.1, L.sup.2, R.sup.1, and R.sup.2 are
as defined above;
[0371] X and Y are heteroatoms selected from N, O, S, and P;
[0372] p is zero when X is O or S, and p is 1 when X is N or P;
[0373] q is zero when Y is O or S, and q is 1 when Y is N or P;
[0374] Q.sup.1, Q.sup.2, Q.sup.3 and Q.sup.4 are independently
selected from hydrocarbylene, substituted hydrocarbylene,
heteroatom-containing hydrocarbylene, substituted
heteroatom-containing hydrocarbylene, and --(CO)--, and further
wherein two or more substituents on adjacent atoms within Q may be
linked to form an additional cyclic group;
[0375] w, x, y, and z are independently zero or 1; and
[0376] R.sup.3, R.sup.3A, R.sup.4, and R.sup.4A are independently
selected from hydrogen, hydrocarbyl, substituted hydrocarbyl,
heteroatom-containing hydrocarbyl, and substituted
heteroatom-containing hydrocarbyl,
[0377] wherein any two or more of X.sup.1, X.sup.2, L.sup.2,
R.sup.1, R.sup.2, R.sup.3, R.sup.3A, R.sup.4, and R.sup.4A can be
taken together to form a cyclic group, and further wherein any one
or more of X.sup.1, X.sup.2, L.sup.2, R.sup.1, R.sup.2, R.sup.3,
R.sup.3A, R.sup.4, and R.sup.4A may be attached to a support.
[0378] The second group of catalysts, accordingly, is exemplified
by the ruthenium carbene complex
(IMesH.sub.2)(PCy.sub.3)(Cl).sub.2Ru.dbd.CHPh (2):
##STR00041##
[0379] Additional transition metal carbene complexes useful as
catalysts in conjunction with the present invention include, but
are not limited to, neutral ruthenium or osmium metal carbene
complexes containing metal centers that are formally in the +2
oxidation state, have an electron count of 16, and are
penta-coordinated. Other preferred metathesis catalysts include,
but are not limited to, cationic ruthenium or osmium metal carbene
complexes containing metal centers that are formally in the +2
oxidation state, have an electron count of 14, and are
tetra-coordinated. Still other preferred metathesis catalysts
include, but are not limited to, neutral ruthenium or osmium metal
carbene complexes containing metal centers that are formally in the
+2 oxidation state, have an electron count of 18, and are
hexa-coordinated.
[0380] ROMP Inhibitors:
[0381] ROMP inhibitors, as described herein, are typically Lewis
base compounds such as triphenyl phosphine (TPP), trialkylphosphite
and pyridine.
[0382] Any other ROMP inhibitors are contemplated.
[0383] Exemplary ROMP Systems:
[0384] Table 1 below presents a list of exemplary components which
can be included, in any combination, in a ROMP system as described
herein in any one of the embodiments and any combinations thereof.
These components can be included in one or more modeling material
formulations, as described herein.
TABLE-US-00003 TABLE 1 Trade Name Chemical Type Function Supplier
ULTRENE .TM. 99 Dicyclopentadiene ROMP Monomer Cymetech DCPD
(bifunctional) ULTRENE .TM. 99-X Cyclopentadiene trimer in ROMP
Monomer Cymetech DCPD (X = 6-20%) dicyclopentadiene (bifunctional)
Cyclopentadiene Cyclopentadiene trimer ROMP Monomer Sinosteel
Anshan trimer (bifunctional) Research Institute of thermo-energy
Cyclooctene Cyclooctene ROMP Monomer Sigma Aldrich Cyclooctadiene
Cyclooctadiene ROMP Monomer Sigma Aldrich Norbornene ROMP Monomer
FA-512AS Dicyclopentadienyloxyethyl Dual curing Hitachi acrylate
ROMP/UV chemicals monomer FA-511AS Dicyclopentadieny acrylate Dual
curing Hitachi ROMP/UV chemicals monomer Kraton no. 1102
Styrene-butadiene-styrene Rubber GLS rubber Polybutadiene Rubber
Lanexss Vistalon ethylene propylene diene Rubber ExonMobile (EPDM)
rubber chemicals Exact plastomers Rubber-plastic ExonMobile
chemicals Ethanox 702 4,4'-Methylenebis(2,6-di- antioxidant
Albemarle tert-butylphenol) Grubbs 1.sup.st Benzylidene- ROMP
catalyst Materia generation catalyst bis(tricyclohexylphosphine)-
(active at room dichlororuthenium temperature) Grubbs 2.sup.nd
[1,3-bis-(2,4,6- ROMP catalyst Materia generation catalysts
trimethylphenyl)-2- (active at room imidazolidinylidene]dichloro
temperature) (phenylmethylene)(tricyclo- hexylphosphine)ruthenium
Hoveyda-Grubbs 1.sup.st Dichloro(o- ROMP catalyst Materia
Generation Catalyst isopropoxyphenylmethylene) (active at room
(tricyclohexylphosphine) temperature) ruthenium(II) Hoveyda-Grubbs
2.sup.nd [1,3-Bis-(2,4,6- ROMP catalyst Materia Generation Catalyst
trimethylphenyl)-2- (active at room imidazolidinylidene]dichloro
temperature) (oisopropoxyphenyl- methylene)ruthenium Umicore 41
[1,3-Bis(mesityl)-2- ROMP catalyst Umicore
imidazolidinyl-idene]-[2- (Pre-catalyst, [[(4-methylphenyl)imino]
activatable by an methyl]-4-nitro-phenolyl]-[3- acid)
phenyl-indenylidene] (chloro)ruthenium(II) Umicore 42
[1,3-Bis(mesityl)-2- ROMP catalyst Umicore imidazolidinylidene]-
(Pre-catalyst, [2-[[(2- activatable by an
methylphenyl)imino]methyl]- acid) phenolyl]-[3-phenyl- indenyliden]
(chloro)ruthenium(II) Umicore 22 cis-[1,3-Bis(2,4,6- ROMP catalyst
Umicore trimethylphenyl)-2- (thermally-
imidazolidinylidene]dichloro activatable latent
(3-phenyl-1H-inden-1- catalyst) ylidene)(triisopropyl-
phosphite)ruthenium(II) Umicore 2 1,3-Bis(2,4,6- ROMP catalyst
Umicore trimethylphenyl)-2- (active at room imidazolidinylidene]
temperature) dichloro(3-phenyl-1H-inden- 1- ylidene)(tricyclohexyl-
phosphine)ruthenium(II) Umicore 61 [1,3-Bis(2,4,6- ROMP catalyst
Umicore trimethylphenyl)-2- (active at room
imidazolidinylidene]dichloro temperature) [2-methyl(phenyl)amino]
benzylidene]ruthenium(II) Triphenyl phosphine Triphenyl phosphine
ROMP inhibitor Sigma Aldrich Triethylphosphite Triethylphosphite
ROMP inhibitor Sigma Aldrich Trimethylphosphite Trimethylphosphite
ROMP inhibitor Sigma Aldrich tributylphosphite tributylphosphite
ROMP inhibitor Sigma Aldrich Irgacure PAG103 PAG BASF (latent
activator) Irgacure PAG121 PAG BASF (latent activator)
Trichloro(phenyl) Trichloro(phenyl)silane Acid generator Aldrich
silane (activator) HCl Acid
[0385] Modeling Material Formulations Comprising a ROMP System:
[0386] According to some of any of the embodiments described
herein, the uncured building material comprises one or more
modeling material formulations which, upon being dispensed, can
undergo a ROMP reaction.
[0387] According to some of any of the embodiments described
herein, the uncured building material comprises one or more
modeling material formulations which form a ROMP system as
described herein.
[0388] As is known in the art and discussed briefly hereinabove,
ROMP reactions typically require a catalyst for initiating the
polymerization reaction. As further discussed herein, once an
active catalyst contacts a ROMP monomer, the polymerization
reaction typically starts immediately, sometime without application
of a curing energy, and hence modeling material formulations in
which an active catalyst, as described herein, is utilized "as is"
together with a ROMP monomer, are inapplicable for 3D inkjet
printing.
[0389] Some embodiments of the present invention therefore relate
to modeling material formulations which are designed such that,
prior to exposure to a suitable condition, the ROMP system is
inactive, that is a ROMP catalyst does not initiate ROMP of the
monomer, and a ROMP monomer does not polymerize via ROMP to provide
a respective polymer, as described herein.
[0390] Some embodiments of the present invention therefore relate
to modeling material formulations which are designed such that,
prior to exposure to a suitable condition, the catalyst does not
initiate the ROMP reaction, that is, prior to exposure to a
suitable condition, at least 50%, preferably at least 60%,
preferably at least 70%, at least 80%, at least 90%, at least 95%
and even 100% of the ROMP monomers do not undergo polymerization.
In other words, prior to exposure of a ROMP system to a suitable
condition, no more than 40% or no more than 30% or no more than 20%
or no more than 10% or no more than 5% of the monomer polymerizes
via ROMP mechanism to provide a respective polymer.
[0391] Such modeling material formulations are characterized by a
viscosity of no more than 35 centipoises, or no more than 25
centipoises at a temperature of the inkjet printing head during the
dispensing.
[0392] In some embodiments, such modeling material formulations are
characterized by the indicated viscosity at a temperature lower
than 70.degree. C., or lower than 65.degree. C., or lower than
60.degree. C., or lower than 50.degree. C., or lower than
40.degree. C., or lower than 30.degree. C., and even at room
temperature (e.g., 25.degree. C.). Such a viscosity is indicative
of the presence (e.g., of more than 80%) of non-polymerizable ROMP
monomers in the formulation, or of the absence (e.g., less than 20%
of the formulation) of polymeric materials obtained by ROMP in the
formulation.
[0393] The modeling material formulations described herein are
designed such that ROMP of the ROMP monomers is not effected when
the formulations pass through the inkjet printing heads.
[0394] Some embodiments of the present invention further relate to
modeling material formulations which are designed such that, upon
exposure to a suitable condition (an inducing condition as
described herein), the ROMP system becomes active, that is a ROMP
catalyst is active towards ROMP of the monomer, and a ROMP monomer
undergoes polymerization via ROMP to provide a respective
polymer.
[0395] Some embodiments of the present invention relate to modeling
material formulations which are designed such that, upon exposure
to a suitable condition, the catalyst initiates the ROMP reaction,
that is, upon exposure to a suitable condition, at least 50%,
preferably at least 60%, preferably at least 70%, at least 80%, at
least 90%, at least 95% and even 100% of the ROMP monomers undergo
polymerization via ROMP reaction.
[0396] In any of the embodiments described herein, the uncured
building material comprises two or more types of a modeling
material formulation. Such embodiments are also referred to herein
as "dual jetting" or "multi jetting" methodology or approach,
respectively. The two or more modeling material formulations form a
formulation system that comprises components of a ROMP system as
described herein, included on one or more, preferably two or more,
of the formulations in the system.
[0397] In some of these embodiments, each of the modeling material
formulations comprises only ROMP monomers as curable materials.
Such embodiments are also referred to herein as "dual jetting
single curing" or "multi-jetting single curing" methodology or
approach.
[0398] In some of these embodiments, the modeling material
formulations comprise in addition to ROMP monomers, also one or
more types of monomers which are polymerizable via a non-ROMP
reaction, as curable materials, which are referred to herein as
non-ROMP materials or non-ROMP curable materials, or non-ROMP
monomers. Such embodiments are also referred to herein as
"multi-jetting multi-curing" or "dual jetting multi-curing" or
"dual jetting dual curing" methodology or approach.
[0399] Generally, in the above terminology, "jetting" refers to the
number of modeling material formulations included in the uncured
building material, and "curing" refers to the number of
polymerization reactions that occur when the dispensed layers are
exposed to a curing condition (e.g., a ROMP inducing condition, or
a ROMP inducing condition and one or more additional curing
conditions).
[0400] It is to be noted that dual curing or multi curing refers
herein to the type of polymerization reactions and not to the
number of conditions applied for inducing curing.
[0401] In some of any of the embodiments described herein, the
uncured building material comprises two or more modeling material
formulations which are dispensed from different inkjet printing
heads (each formulation is jetted from a different printing head or
a different set of printing heads) to form the layers.
[0402] Such a methodology, which is referred to herein as dual
jetting, when two different modeling material formulations are
used, or as multi-jetting, when more than two modeling material
formulations are used, allows dispensing modeling material
formulations which are absent of one or more of the components
required for a polymerization or curing to occur, whereby when the
formulations are dispensed and contact one another, curing and/or
polymerization occurs.
[0403] In the context of some of the present embodiments, such a
methodology allows separating ROMP components as described herein
by including a different combination of components in each
formulation, whereby none of the formulations comprises all the
components required for the ROMP reaction to occur. According to
these embodiments, a ROMP reaction, and optionally non-ROMP
reactions, occur only on the receiving medium, and after the
uncured building material is dispensed, and optionally and
preferably exposed to a curing condition as described herein.
[0404] In some of these embodiments, exposing the formulation to a
condition for initiating ROMP can be effected by contacting the
different formulations on the receiving medium (receiving tray). In
some of these embodiments, exposing to a ROMP inducing condition is
effected by dispensing the formulations.
[0405] Connex 3.TM. (Stratasys Ltd., Israel) multiple material
deposition technology, is an exemplary technology that provides the
possibility to separate the components of a polymerizable or
curable system into different formulations. Objet Connex 3.TM.
(Stratasys Ltd., Israel) multiple material deposition system, is a
system that allows utilizing such a technology.
[0406] Multi-Jetting (e.g., Dual Jetting) Single Curing:
[0407] In some of any of these embodiments, the uncured building
material comprises two or more modeling material formulations, and
the two or more modeling material formulations are such that when
combined, curing is effected by ROMP reaction.
[0408] In some of these embodiments, each of the modeling material
formulations comprises a ROMP monomer (which can be the same or
different).
[0409] In some of these embodiments, each of the modeling material
formulations comprises a ROMP monomer (which can be the same or
different), and one of the formulations further comprises a ROMP
catalyst.
[0410] In some of these embodiments, the uncured building material
comprises more than two modeling material formulations, each
independently comprising a ROMP monomer (which can be the same or
different), and one or two of these formulations further comprises
a ROMP catalyst.
[0411] In some of any of these embodiments, one or more of the
modeling material formulations is devoid of a ROMP catalyst, and in
some embodiments, one or more of the modeling material formulations
comprises a ROMP monomer and a ROMP catalyst.
[0412] In some of these embodiments, one or more of the ROMP
catalysts is an active catalyst, as described herein.
[0413] In some of these embodiments, the formulations comprise two
or more types of catalysts.
[0414] In exemplary embodiments, the two or more catalysts are
active catalysts.
[0415] In some of these embodiments, the formulations comprise two
or more types of ROMP monomers.
[0416] In some of these embodiments, each of the ROMP active
catalysts has a different reactivity towards initiation of ROMP of
the different monomers.
[0417] In some exemplary embodiments, a ROMP system of the modeling
material formulations comprises first and second ROMP monomers, and
first and second ROMP active catalysts. The first ROMP active
catalyst has a higher reactivity towards initiation of ROMP of the
first monomer, and the second ROMP active catalyst has a higher
reactivity towards initiation of ROMP of the second monomer.
[0418] In some of these embodiments, one of the formulations
comprises a first ROMP monomer and the second active catalyst that
is less reactive towards initiation of ROMP of the first monomer
and has a higher reactivity towards initiation of ROMP of the
second ROMP monomer, and another one of the formulations comprises
the first active catalyst that is less reactive towards initiation
of ROMP of the second ROMP monomer and has a higher reactivity
towards initiation of ROMP of the first ROMP monomer.
[0419] Such exemplary embodiments allow using active catalysts
while avoiding substantial clogging of the inkjet printing
heads.
[0420] In some of any of the embodiments described herein, the ROMP
catalyst(s) include one or more latent catalysts, which are
activatable upon exposure to a ROMP inducing condition, as
described herein.
[0421] A method, according to these embodiments, comprises exposing
the dispensed layers to a condition that activates the catalyst, as
described herein.
[0422] In some embodiments, the ROMP system further comprises an
activator and the catalyst is a pre-catalyst, as described
herein.
[0423] In some of these embodiments, each of the modeling material
formulations independently comprises a ROMP monomer, one or more of
the formulations further comprise a pre-catalyst, and one or more
other formulations further comprise an activator. In some of these
embodiments, the one or more formulations that comprise the
activator are devoid of the pre-catalyst. In some embodiments, the
one or more formulations that comprise the pre-catalyst are devoid
of an activator.
[0424] In some of these embodiments, exposing the dispensed layers
to inducing condition is effected by the contacting the
formulations on the receiving medium, and hence comprises the
formation of the dispensed layers (e.g., by jetting the modeling
material formulation by the inkjet printing heads).
[0425] In some of any of the embodiments described herein, the ROMP
system comprises a latent activator.
[0426] In some of these embodiments, exposing the dispensed layers
to inducing condition is effected by exposing the dispensed
formulations to a condition that activates the activator.
[0427] In some of any of the embodiments described herein, one or
more of the components in one or more of the formulations is
physically separated from the other components in the
formulation.
[0428] Physical separation can be effected, for example, by
encapsulation of one or more components of the ROMP system.
[0429] By "encapsulation" it is meant that a component is enveloped
by a capsule, whereby a capsule is used herein to describe a closed
structure by which a component is enveloped. In some embodiments,
the capsule has a core-shell structure in which the core is the
encapsulated component which is enveloped by a shell.
[0430] Herein, the terms "physically separated" and "encapsulated"
or "physical separation" and "encapsulation" are sometimes used
interchangeably, for simplicity.
[0431] The capsule may have any shape and can be made of any
material.
[0432] In some embodiments, the capsule is designed so as to
release its content, namely, the encapsulated ROMP component (ROMP
monomer or ROMP catalyst) upon being exposed to a condition.
[0433] In some embodiments, exposure to a condition that induces
initiation of ROMP monomer by the ROMP catalyst comprises exposure
to a condition that affects release of a ROMP component from a
capsule. That is, the ROMP inducing condition is a condition that
degrades a capsule and results in contacting the catalyst with the
ROMP monomer.
[0434] In some embodiments, the release of a ROMP component from a
capsule is effected by exposure to a condition that affects
degradation of the capsule.
[0435] Degradation of the capsule can be effected, for example,
mechanically, so as to affect rupture or breaking of the capsule,
and the condition is such that causes mechanical degradation of the
capsule.
[0436] The mechanical degradation can be effected, for example, by
application of mechanical forces such as shear forces.
[0437] In some embodiments, mechanical degradation is effected by
exposing the capsule to shear forces, for example, by passing a
modeling material formulation comprising the capsule through one or
more inkjet printing heads (e.g., Ricoh Gen 3) which allow jetting
at a frequency range of from about 10 kHz to about 30 kHz.
[0438] Alternatively, shear forces at such a rate are applied to
the dispensed layers of the formulation (e.g., to the receiving
tray).
[0439] Degradation of the capsule can be effected, for example,
physically or chemically, by application of, for example, heat or
radiation to the capsule so as to decompose capsule or melt the
capsule's shell.
[0440] Degradation of the capsule can thus be effected by exposing
the capsule to heat or radiation, to thereby release its
content.
[0441] Non-limiting examples for encapsulation of a ROMP catalyst
and/or a ROMP monomer include utilizing capsules made of, for
example, wax, degradable polymeric materials, degradable micelles,
sol-gel matrices, and/or clays. Exemplary degradable capsules are
described, for example, in Adv. Funct. Mater. 2008, 18, 44-52; Adv.
Mater. 2005, 17, 39-42; and Pastine, S. J.; Okawa, D.; Zettl, A.;
Frechet, J. M. J. J. Am. Chem. Soc. 2009, 131, 13586-13587. doi:
10.1021/ja905378v; all of which are incorporated by reference as if
fully set forth herein.
[0442] In some embodiments, one or more of the ROMP catalyst (e.g.,
an active catalyst) and a ROMP monomer is encapsulated (e.g.,
individually encapsulated, in case both are encapsulated) in a
capsule and exposing a modeling material formulation to the
inducing condition comprises passing the formulation through the
inkjet printing heads at a shear rate that causes mechanical
degradation of the capsule and release on the encapsulated
component.
[0443] In some embodiments, one or more of the ROMP catalyst (e.g.,
an active catalyst) and a ROMP monomer is encapsulated (e.g.,
individually encapsulated, in case both are encapsulated) in a
capsule and exposing a modeling material formulation to the
inducing condition comprises exposing the dispensed formulation to
heat or radiation to thereby cause degradation of the capsule and
release the encapsulated component from the capsule.
[0444] In some of any of the embodiments described herein, the
formulation comprises a plurality of capsules encapsulating one or
both of the ROMP components. The capsules can be the same or
different and can release their content when exposed to the same or
different inducing condition.
[0445] In some of any of the embodiments described herein, one or
more, or each, of the modeling material formulations further
comprises a ROMP inhibitor.
[0446] In some of any of the embodiments described herein, one or
more, or each, of the modeling material formulations, further
comprises additional materials, as is described in further detail
hereinunder.
[0447] In some of any of the embodiments described herein,
converting the ROMP system or systems to active ROMP systems is
effected by a single condition. For example, in some embodiments,
activating of a latent catalyst, if present in one or more of the
formulations, of a latent activator, if present in one or more of
the formulations, and/or release of one or more components that are
encapsulated (e.g., degradation of capsules enveloping a ROMP
component, if present in one or more of the formulations), are all
effected upon exposing the dispensed formulations to the same
condition. The condition can be, for example, radiation (e.g., UV
radiation), such that the ROMP system or systems in the two or more
modeling material formulations is/are photoactivatable. The
condition can be, for example, heat, such that the ROMP system or
systems in the two or more modeling material formulations is/are
thermally-activatable.
[0448] Multi (e.g., Dual) Jetting Multi (e.g., Dual) Curing:
[0449] In some of the embodiments described herein pertaining to
multi-curing or dual curing, the two or more modeling material
formulations comprise, in addition to ROMP components, components
of one or more non-ROMP curable systems, which undergo
polymerization and/or curing via a non-ROMP reaction.
[0450] A non-ROMP reaction refers to any polymerization and/or
curing reactions that do not involve ROMP. Such reactions include,
for example, chain growth polymerization such as free-radical
polymerization, cationic polymerization, anionic polymerization,
and step-growth polymerization such as polycondensation.
[0451] In some embodiments, a curable system which undergoes
polymerization and/or curing via a non-ROMP reaction, as described
herein, comprises monomers and/or oligomers which are polymerizable
by a non-ROMP reaction as described herein. Such materials are also
collectively referred to herein as non-ROMP polymerizable materials
or monomers, or non-ROMP curable materials or monomers.
[0452] A curable system which undergoes polymerization and/or
curing via a non-ROMP reaction can alternatively, or in addition,
comprise short-chain polymeric materials which undergo curing by,
for example, cross-linking, whereby the curing comprises
free-radical cross-linking, cationic or anionic cross-linking,
and/or polycondensation. Such materials are also encompassed herein
by the expressions non-ROMP polymerizable materials or monomers, or
non-ROMP curable materials or monomers.
[0453] A curable system which undergoes polymerization and/or
curing via a non-ROMP reaction may comprise one or more curable
materials that undergo polymerization and/or curing via a non-ROMP
reaction, and optionally one or more initiators for initiating a
respective non-ROMP reaction. In some embodiments, such a system
further comprises a condition for inducing initiation of the
non-ROMP reaction.
[0454] A curable system which undergoes polymerization and/or
curing via a non-ROMP reaction is also referred to herein as a
non-ROMP curable system.
[0455] In some of these embodiments, the uncured building material
further comprises, in addition to the ROMP components described
herein, one or more curable materials that undergo polymerization
and/or curing via a non-ROMP reaction, and optionally one or more
initiators for initiating a respective non-ROMP reaction.
[0456] In some of any of the embodiments pertaining to a dual
curing approach, the method further comprises exposing the modeling
material formulation to a condition for inducing initiation of a
respective polymerization and/or curing via a non-ROMP
reaction.
[0457] In some embodiments, the condition for inducing
polymerization and/or curing via a non-ROMP reaction is the same as
the ROMP indicting condition, and in some embodiments, it is a
different condition.
[0458] When the condition is different from the ROMP inducing
condition, exposure to the conditions can be effected
simultaneously or sequentially. The order can be determined as
desired, by any person skilled in the art.
[0459] In some of any of the embodiments described herein, the
non-ROMP curable system is polymerizable or curable by free radical
polymerization. In some of these embodiments, the uncured building
material comprises, in addition to a selected ROMP system as
described herein in any of the respective embodiments, a monomer
and/or oligomer that is polymerizable by a free radical
polymerization and a free radical initiator.
[0460] In some of any of the embodiments described herein, the
non-ROMP curable system is polymerizable or curable by cationic
polymerization. In some of these embodiments, the uncured building
material comprises, in addition to a selected ROMP system as
described herein in any of the respective embodiments, a monomer
and/or oligomer that is polymerizable by a cationic polymerization
and a suitable catalyst (e.g., a cationic initiator, optionally
combined with a suitable promoter or activator).
[0461] In some of any of the embodiments described herein, the
non-ROMP curable system is polymerizable or curable by anionic
polymerization. In some of these embodiments, the uncured building
material comprises, in addition to a selected ROMP system as
described herein in any of the respective embodiments, a monomer
and/or oligomer that is polymerizable by anionic polymerization and
a suitable catalyst (e.g., an anionic initiator or a catalyst,
optionally combined with a suitable promoter or activator).
[0462] In some of any of the embodiments described herein, the
non-ROMP initiator is a latent initiator, which is activatable upon
exposure to a curing condition, as described herein.
[0463] The components of such a building material therefore undergo
polymerization and/or curing via ROMP polymerization and also by
one or more non-ROMP reactions, as described herein.
[0464] In some of these embodiments, the components of the two or
more modeling material formulations form two curable systems, for
example, one or more ROMP system(s) and one or more of a free
radial polymerization system, a cationic polymerization system, an
anionic polymerization system, etc. Any polymerization system that
is usable in 3D inkjet printing is contemplated.
[0465] In some of any of these embodiments, the ROMP components can
include one or more ROMP monomers and one or more catalysts, for
example, active catalysts.
[0466] In some of the embodiments when an active catalyst is used,
the active catalyst is included in a modeling material formulation
that is devoid of a ROMP monomer, and which, in some embodiments,
comprises a material that is polymerizable by a non-ROMP reaction
(a non-ROMP curable or polymerizable material) as described
herein.
[0467] In some of the embodiments when an active catalyst is used,
one or more of the modeling material formulations comprises a ROMP
monomer or monomers, and is devoid of a catalyst, and another one
or more modeling material formulation comprises a ROMP catalyst
which is an active catalyst, and is devoid of a ROMP monomer.
[0468] Alternatively, in any one of these embodiments, the catalyst
is a latent catalyst.
[0469] Further alternatively, in any one of these embodiments, the
catalyst is physically separated from the other components in the
formulation containing same. Physical separation can be effected by
means of degradable capsules, as described herein.
[0470] In any one of the embodiments when a latent catalyst is
used, the inducing condition comprises a condition which activates
the catalyst, as described herein.
[0471] In any one of the embodiments when an encapsulated catalyst
is used, the inducing condition comprises a condition which
degrades the capsule so as to release the active catalyst.
[0472] Alternatively, in any one of these embodiments, the catalyst
is a pre-catalyst and the one or more of the modeling material
formulations comprises an activator or a latent activator, as
described herein.
[0473] In some of these embodiments, one or more of the modeling
material formulations comprise a ROMP monomer and a pre-catalyst
and other one or more modeling material formulations comprise the
activator. Alternatively, one or more of the modeling material
formulations comprise a ROMP monomer and the activator and other
one or more modeling material formulations comprise the
pre-catalyst.
[0474] Whenever the activator is included in the formulation(s) as
active towards chemically activating the pre-catalyst to provide an
active catalyst, the inducing condition for effecting ROMP can be
contacting the respective formulations on the receiving medium
(tray). Thus exposing to the condition is effected by jetting the
formulations by the inkjet printing heads (dispensing the layers of
the formulations).
[0475] Further alternatively, one or more of the modeling material
formulations comprise a ROMP monomer and other one or more modeling
material formulations comprise the activator and the pre-catalyst.
In some of these embodiments, the activator is a latent activator
and/or one or both of the activator and the pre-catalyst are
physically separated from one another, as described herein.
[0476] In some of any of the embodiments described herein, one or
more of the modeling material formulations further comprises a
non-ROMP curable material (a material polymerizable or curable by a
non-ROMP reaction as described herein).
[0477] In some of these embodiments, the non-ROMP curable material
is included in a formulation which comprises a ROMP catalyst
(active, latent or pre-catalyst, encapsulated or non-encapsulated)
and/or a ROMP activator (active or latent, encapsulated or
non-encapsulated).
[0478] In some of these embodiments, one or more formulations
comprise a ROMP monomer and one or more other formulations comprise
a non-ROMP curable material and a ROMP catalyst (active, latent or
pre-catalyst, encapsulated or non-encapsulated) and/or a ROMP
activator (active or latent, encapsulated or non-encapsulated), and
is devoid of a ROMP monomer.
[0479] In exemplary embodiments of a dual jetting methodology, one
modeling material formulation, formulation A, comprises a ROMP
monomer and another modeling material formulation, formulation B
comprises a non-ROMP curable material. In some embodiments,
formulation A further comprises a ROMP pre-catalyst (optionally
encapsulated) and formulation B further comprises a ROMP activator
(latent or not, encapsulated or non-encapsulated). In some
embodiments, formulation A further comprises a ROMP activator
(latent or not, optionally encapsulated) and formulation B further
comprises a ROMP pre-catalyst (optionally encapsulated). In some
embodiments, formulation B further comprises a ROMP catalyst
(latent or active, optionally encapsulated). In some embodiments,
formulation B further comprises a ROMP activator (latent or not,
encapsulated or non-encapsulated) and a ROMP pre-catalyst
(optionally encapsulated).
[0480] Other combinations are also contemplated. For example, in
any of the formulations described herein for the multi-jetting
single curing methodology, a ROMP monomer in one or more of the
modeling material formulations can be replaced by a non-ROMP
curable material.
[0481] In some of any of the embodiments described herein, one or
more of the modeling material formulations, according to any one of
the embodiments described herein and any combination thereof,
further comprises an initiator of the non-ROMP reaction (a non-ROMP
initiator).
[0482] In some of these embodiments, the initiator is comprised in
one or more modeling material formulations which are devoid of a
non-ROMP curable material. In some embodiments, one or more of the
modeling material formulations comprise a ROMP monomer and a
non-ROMP initiator. In some embodiments, such a formulation is
devoid of one or more of the ROMP components of the ROMP system
(e.g., a catalyst, an activator, a pre-catalyst).
[0483] In exemplary embodiments of a dual jetting methodology
according to these embodiments, one modeling material formulation,
formulation A, comprises a ROMP monomer and another modeling
material formulation, formulation B comprises a non-ROMP curable
material. In some embodiments, formulation A further comprises a
ROMP pre-catalyst (optionally encapsulated) and a non-ROMP
initiator (latent or active, optionally encapsulated), and
formulation B further comprises a ROMP activator (latent or not,
encapsulated or non-encapsulated). In some embodiments, formulation
A further comprises a ROMP activator (latent or not, optionally
encapsulated) and a non-ROMP initiator (latent or active,
optionally encapsulated), and formulation B further comprises a
ROMP pre-catalyst (optionally encapsulated). In some embodiments,
formulation A further comprises a non-ROMP initiator (latent or
active, optionally encapsulated) and formulation B further
comprises a ROMP catalyst (latent or active, optionally
encapsulated). In some embodiments, formulation A further comprises
a ROMP activator (latent or not, optionally encapsulated) and a
non-ROMP initiator (latent or active, optionally encapsulated), and
formulation B further comprises a ROMP activator (latent or not,
encapsulated or non-encapsulated) and a ROMP pre-catalyst
(optionally encapsulated).
[0484] Other combinations are also contemplated. For example, in
any of the formulations described herein for the multi-jetting
single curing methodology, a ROMP monomer in one or more of the
modeling material formulations can be replaced by a non-ROMP
curable material, and one or more of the formulations further
comprises a non-ROMP initiator (latent or active, optionally
encapsulated).
[0485] In some of any of the embodiments described herein, the
method further comprises exposing the formulation to one or more
conditions for inducing polymerization and/or curing of the one or
more non-ROMP curable systems. In some embodiments, the condition
for inducing ROMP and the condition for inducing polymerization
and/or curing of the non-ROMP curable material(s) are the same. In
some embodiments, the conditions are different and can be applied
simultaneously or sequentially, as desired or required.
[0486] Curable Systems:
[0487] A "curable system" as described herein refers to a system
that comprises one or more curable materials, as defined
herein.
[0488] In some of any of the embodiments described herein, a
"curable system" comprises one or more curable materials and
optionally one or more initiators and/or catalysts for initiating
curing of the curable materials, and, further optionally, one or
more conditions (also referred to herein as curing conditions) for
inducing the curing, as described herein.
[0489] In some of any of the embodiments described herein, a
curable material is a monomer or a mixture of monomers and/or an
oligomer or a mixture of oligomers which can form a polymeric
material upon a polymerization reaction, when exposed to a
condition at which curing, as defined herein, occurs (a condition
that affects or induces curing).
[0490] A "bifunctional" or "multifunctional" curable material or
monomer is meant to describe curable materials that result in a
polymeric material that features two or more functional groups, and
hence can act also as a cross-linker, for cross-linking polymeric
chains formed of the same and/or different curable materials in the
building material.
[0491] In some embodiments, a curable system further comprises an
initiator for initiating the curing and/or polymerization of the
curable material(s). The initiator can be active towards the
initiation of the curing and/or polymerization in the curable
system or can be inactive towards this initiation.
[0492] Inactive initiators can be latent initiators, which are
activatable upon exposure to a condition, and this condition
induces the curing and/or polymerization.
[0493] Alternatively, inactive initiators can be inactive due to
physical separation from the curable material(s). The physical
separation can be effected by means of capsules, preferably
degradable capsules as described herein. Such initiators are
activatable by a condition that removes the physical separation,
e.g., induces release of the initiator from the capsule, as
described herein.
[0494] Further alternatively, inactive initiators can be chemically
activated by an activator, and become active upon a condition that
results in contacting the activator, similarly to any of the
embodiments described herein in the context of a pre-catalyst and
an activator.
[0495] In some of any of the embodiments described herein,
depending on its components and chemistry, a curable system further
requires a condition for effecting curing and/or polymerization of
the curable materials.
[0496] In some of any of the embodiments described herein, the one
or more modeling material formulations comprise a curable system
that is an active system, namely, the components included in the
one or more modeling material formulations can undergo
polymerization or curing without a stimulus.
[0497] In some of any of the embodiments described herein, the one
or more modeling material formulation comprise a curable system
that is inactive, namely, the components included in the one or
more modeling material formulations can undergo polymerization or
curing only when exposed to a condition that induces curing.
[0498] A curable system as described herein may comprise, in
addition to a curable material, an initiator and optionally an
activator.
[0499] A curable system as described herein can be a ROMP system,
as described herein in any of the respective embodiments, which
comprises one or more ROMP monomers, as described herein in any of
the respective embodiments.
[0500] In embodiments pertaining to dual or multi-curing, along
with dual or multi-jetting, the two or more modeling material
formulations further comprise components of additional, one or more
curable systems, either in the same, and preferably, in different
formulations.
[0501] Herein throughout, curable systems which comprise curable
materials that are curable and/or polymerizable via a
polymerization or curing reaction other than ROMP, are referred to
herein also as non-ROMP curable systems. The components of such
systems are also referred to herein as non-ROMP components, for
example, non-ROMP curable materials, non-ROMP initiators, non-ROMP
activators, and non-ROMP inducing condition (or condition for
inducing non-ROMP polymerization and/or curing or for initiating a
non-ROMP reaction).
[0502] In some of any of the embodiments described herein, a
concentration of a curable material, including a ROMP monomer, in a
modeling material formulation containing same ranges from about 20%
to about 99% or from about 50% to about 99% by weight of the total
weight of the modeling material formulation, including any
subranges and intermediate values therebetween.
[0503] In some of these embodiments, a modeling material
formulation comprises a single curable material, at the indicted
concentration range.
[0504] In some of these embodiments, a modeling material
formulation comprises two or more curable materials, and the total
concentration of curable materials ranges from about 20% or from
about 50% to about 99% by weight of the total weight of the
formulation.
[0505] In some of any of the embodiments described herein, a
concentration of additional reactive components in a curable system
as described herein, including, for example, a ROMP catalyst, a
ROMP activator, a non-ROMP initiator, a non-ROMP activator (or
co-initiator), in a modeling material formulation containing same
individually ranges (for each component) from about 0.001% to about
10%, or from about 0.01% to 5% by weight of the total weight of the
modeling material formulation, including any subranges and
intermediate values therebetween.
[0506] In some embodiments, a concentration of a ROMP catalyst
(active or latent) or a ROMP pre-catalyst in a modeling material
formulation containing same independently ranges from about 0.001%
to about 1%, or from about 0.001% to about 0.1% by weight of the
total weight of the modeling material formulation, including any
subranges and intermediate values therebetween.
[0507] In some embodiments, a concentration of a ROMP inhibitor in
a modeling material formulation containing same independently
ranges from about 0.001% to about 1%, or from about 0.001% to about
0.1% by weight of the total weight of the modeling material
formulation, including any subranges and intermediate values
therebetween.
[0508] In some embodiments, a concentration of a ROMP activator
(active or latent) in a modeling material formulation containing
same independently ranges from about 0.001% to about 5%, or from
about 0.001% to about 1% by weight of the total weight of the
modeling material formulation, including any subranges and
intermediate values there between. In some of these embodiments, a
modeling material formulation comprises a single reactive
component, at the indicted concentration range.
[0509] In some of these embodiments, a modeling material
formulation comprises two or more curable materials reactive
components, and the total concentration of the reactive components
materials ranges from about 0.001% to about 10% by weight of the
total weight of the formulation, including any subranges and
intermediate values therebetween.
[0510] In some of any of the embodiments described herein,
components which form a curable system as described herein are
referred to as reactive components or materials, and curable
components are referred to as reactive polymerizable components,
materials, monomers, or groups, interchangeably.
[0511] In some of any of the embodiments described herein, a
curable material can be a monofunctional curable material, which
comprises one polymerizable group that participates in the
polymerization or curing, or a bifunctional or multifunctional
curable material, as defined herein.
[0512] Additional components included in the modeling material
formulations as described herein, which do not undergo a
polymerization and/or curing, are also referred to herein as
non-reactive materials or components.
[0513] Non-ROMP curable systems according to some of the present
embodiments, can be, for example, curable systems in which the
non-ROMP curable material(s) undergo curing and/or polymerization
via free radical polymerization. Such systems are also referred to
herein as free-radical curable systems.
[0514] Any free-radical curable system that is usable in 3D inkjet
printing processes and systems is contemplated by these
embodiments.
[0515] In some embodiments, free-radical polymerizable (curable)
components may include mono-functional and/or multi-functional
acrylic and/or methacrylic monomers, acrylic and/or methacrylic
oligomers, and any combination thereof. Other free-radical
polymerizable compounds may include vinyl ethers and other
components (monomers or oligomers) with a reactive double bond.
[0516] An acrylic or methacrylic oligomer can be, for example, a
polyester of acrylic acid or methacrylic acid, oligomers of
urethane acrylates and urethane methacrylates. Urethane-acrylates
are manufactured from aliphatic or aromatic or cycloaliphatic
diisocyanates or polyisocyanates and hydroxyl-containing acrylic
acid esters. Oligomers may be mono-functional or multifunctional
(for example, di-, tri-, tetra-functional, and others). An example
is a urethane-acrylate oligomer marketed by IGM Resins BV (The
Netherlands) under the trade name Photomer-6010.
[0517] An acrylic or methacrylic monomer can be, for example, an
ester of acrylic acid or methacrylic acid. Monomers may be
mono-functional or multifunctional (for example, di-, tri-,
tetra-functional, and others). An example of an acrylic
mono-functional monomer is phenoxyethyl acrylate, marketed by
Sartomer Company (USA) under the trade name SR-339. An example of
an acrylic di-functional monomer is propoxylated (2) neopentyl
glycol diacrylate, marketed by Sartomer Company (USA) under the
trade name SR-9003.
[0518] Either the monomer or the oligomer might be polyfunctional,
and can be, for example, Ditrimethylolpropane Tetra-acrylate
(DiTMPTTA), Pentaerythitol Tetra-acrylate (TETTA), Dipentaerythitol
Penta-acrylate (DiPEP). Any other curable material that is
polymerizable by free radical polymerization is contemplated.
[0519] In some embodiments, a free-radical polymerizable material
is polymerizable or curable by exposure to radiation. Systems
comprising such a material can be referred to as
photo-polymerizable free-radical systems, or photoactivatable
free-radical systems.
[0520] In some embodiments, a free-radical curable system further
comprises a free radical initiator, which produces free radicals
for initiating the polymerization and/or curing.
[0521] In some embodiments, a condition for initiating free-radical
curing and/or polymerization comprises is a condition that induced
free radical generation by the initiator. The initiator in such
cases is a latent initiator, which produces free radicals when
exposed to the condition.
[0522] In some embodiments, the initiator is a free-radical
photoinitiator, which produces free radicals when being exposed to
radiation.
[0523] In some of any of the embodiments described herein for
free-radical curable systems, the radiation is UV radiation, and
the system is a UV-curable system.
[0524] A free-radical photoinitiator may be any compound that
produces a free radical on exposure to radiation such as
ultraviolet or visible radiation and thereby initiates a
polymerization reaction. Non-limiting examples of suitable
photoinitiators include benzophenones (aromatic ketones) such as
benzophenone, methyl benzophenone, Michler's ketone and xanthones;
acylphosphine oxide type photo-initiators such as
2,4,6-trimethylbenzolydiphenyl phosphine oxide (TMPO),
2,4,6-trimethylbenzoylethoxyphenyl phosphine oxide (TEPO), and
bisacylphosphine oxides (BAPO's); benzoins and bezoin alkyl ethers
such as benzoin, benzoin methyl ether and benzoin isopropyl ether
and the like. Examples of photoinitiators are alpha-amino ketone,
and bisacylphosphine oxide (BAPO's).
[0525] A free-radical photo-initiator may be used alone or in
combination with a co-initiator. Co-initiators are used with
initiators that need a second molecule to produce a radical that is
active in the photocurable free-radical systems. A co-initiator of
a photoinitiator is also referred to herein as a non-ROMP
activator. Benzophenone is an example of a photoinitiator that
requires a second molecule, such as an amine, to produce a free
radical. After absorbing radiation, benzophenone reacts with a
ternary amine by hydrogen abstraction, to generate an alpha-amino
radical which initiates polymerization of acrylates. Non-limiting
example of a class of co-initiators are alkanolamines such as
triethylamine, methyldiethanolamine and triethanolamine.
[0526] Representative examples of UV curable materials of a
free-radical curable system include, but are not limited to,
tricyclodecane dimethanol diacrylate SR 833S, Phenoxy ethyl
Acrylate SR 339, Isobornyl acrylate SR 506D and etc. Other examples
are provided in Table 2 herein.
[0527] In some of any of the embodiments described herein, one or
more of the modeling material formulations containing a
free-radical curable system comprises a radical inhibitor, for
preventing or slowing down polymerization and/or curing prior to
exposing to the curing condition.
[0528] In some of any of the embodiments described herein, the one
or more additional curable systems is/are polymerizable or cured
via cationic polymerization, and are referred to herein also as
cationic polymerizable or cationic curable systems.
[0529] The curable components or materials of such systems undergo
polymerization or curing via cationic polymerization.
[0530] Exemplary cationically polymerizable components include, but
are not limited to, epoxy-containing materials (monomers or
oligomers), caprolactams, caprolactones, oxetanes, and vinyl ethers
(monomers or oligomers).
[0531] Non-limiting examples of epoxy-containing curable compounds
include Bis-(3,4 cyclohexylmethyl) adipate, 3,4-epoxy
cyclohexylmethyl-3,4-epoxycyclohexyl carboxylate, 1,2
epoxy-4-vinylcyclohexane, 1,2-epoxy hexadecane, 3,4-epoxy
cyclohexylmethyl-3,4-epoxy cyclohexane carboxylate, which is
available, for example, under the trade name UVACURE 1500 from
Cytec Surface Specialties SA/NV (Belgium) and mono or
multifunctional silicon epoxy resins such as PC 1000 which is
available from Polyset Company (USA).
[0532] In some embodiments, a cationic polymerizable material is
polymerizable or curable by exposure to radiation. Systems
comprising such a material can be referred to as
photo-polymerizable cationic systems, or photoactivatable cationic
systems.
[0533] In some embodiments, a cationic curable system further
comprises a cationic initiator, which produces cations for
initiating the polymerization and/or curing.
[0534] In some embodiments, a condition for initiating cationic
curing and/or polymerization comprises is a condition that induced
cation generation by the initiator. The initiator in such cases is
a latent initiator, which produces cations when exposed to the
condition.
[0535] In some embodiments, the initiator is a cationic
photoinitiator, which produces cations when exposed to
radiation.
[0536] In some of any of the embodiments described herein for
cationic curable systems, the radiation is UV radiation, and the
system is a cationic UV-curable system.
[0537] Suitable cationic photoinitiators include, for example,
compounds which form aprotic acids or Bronstead acids upon exposure
to ultraviolet and/or visible light sufficient to initiate
polymerization. The photoinitiator used may be a single compound, a
mixture of two or more active compounds, or a combination of two or
more different compounds, i.e. co-initiators. Non-limiting examples
of suitable cationic photoinitiators include aryldiazonium salts,
diaryliodonium salts, triarylsulphonium salts, triarylselenonium
salts and the like. An exemplary cationic photoinitiator is a
mixture of triarylsolfonium hexafluoroantimonate salts.
[0538] Non-limiting examples of suitable cationic photoinitiators
include P-(octyloxyphenyl) phenyliodonium hexafluoroantimonate
UVACURE 1600 from Cytec Company (USA), iodonium
(4-methylphenyl)(4-(2-methylpropyl)phenyl)-hexafluorophosphate
known as Irgacure 250 or Irgacure 270 available from Ciba
Speciality Chemicals (Switzerland), mixed arylsulfonium
hexafluoroantimonate salts known as UVI 6976 and 6992 available
from Lambson Fine Chemicals (England), diaryliodonium
hexafluoroantimonate known as PC 2506 available from Polyset
Company (USA), (tolylcumyl) iodonium tetrakis (pentafluorophenyl)
borate known as Rhodorsil.RTM. Photoinitiator 2074 available from
Bluestar Silicones (USA), iodonium
bis(4-dodecylphenyl)-(OC-6-11)-hexafluoro antimonate known as Tego
PC 1466 from Evonik Industries AG (Germany).
[0539] In some of any of the embodiments described herein, the
non-ROMP curable system is any other system that is usable in
3D-printing processes and systems. Additional examples include,
without limitation, systems based on polyurethane chemistry, in
which isocyanate-containing compounds and hydroxyl-containing
compounds (e.g., polyols) react via polycondensation in the
presence of a catalyst and/or upon exposure to UV radiation), thiol
chemistry, in which mercaptopropionate-based curable materials
polymerize when exposed to UV in the presence of a free-radical
photoinitiator, and more.
[0540] In some of any of the embodiments described herein, the
non-ROMP curable systems comprise a combination of two or more
non-ROMP curable systems.
[0541] In some of any of the embodiments described herein, at least
one, and preferably each, of the non-ROMP curable systems in the
modeling material formulations described herein is activatable upon
exposure to the same condition as does a ROMP system. That is,
curing of all the curable systems is effected upon exposure to the
same curing inducing condition, as described herein.
[0542] In some of these embodiments, the ROMP system is a
photoactivatable system and the one or more non-ROMP curable
systems are also photoactivatabe systems.
[0543] In some of these embodiments, the systems are UV-curable,
that is, the condition inducing curing is effected by exposure to
UV radiation, as described herein.
[0544] Photoactivatable ROMP systems are described herein.
[0545] Photoactivatable non-ROMP systems may include free radical
photopolymerizable compounds (e.g., Tricyclodecane dimethanol
diacrylate SR 833S, Phenoxy ethyl Acrylate SR 339, Isobornyl
acrylate SR 506D and so on), and/or cationic polymerizable
compounds (e.g., cycloaliphatic epoxide Uvacure 1500, epoxidized
polybutadiene polyBD605E, limonene dioxide Celloxide 3000,
Difunctional silicon-containing epoxy resin PC2000, etc.),
optionally in combination with a free radical photoinitiator or a
cationic photoinitiator, respectively, as described herein.
[0546] In some of any of the embodiments described herein, when a
curable system is photoactivatable, a modeling material formulation
can further comprise a photosensitizer.
[0547] In dual or multi-jetting methodologies, the photosensitizer
can be included in a modeling material formulation that comprises a
respective photocurable material (including a ROMP monomer) or in
another formulation, that is devoid of the photocurable material.
In some embodiments, the photosensitizer is included in a modeling
material that is devoid of one or more of the components which are
activatable by exposure to radiation. Such components include, for
example, an active ROMP catalyst that is encapsulated by a
photodegradable capsule, a latent ROMP catalyst that is
photoactivatable, a latent activator that is photoactivatable, an
activator that is encapsulated by a photodegradable capsule, a
photoinitiator, as described herein, an initiator or co-initiator
that in encapsulated in photodegradable capsule, and so forth.
[0548] Exemplary photosensitizers include, but are not limited to,
2-isopropylthioxanthone and 4-isopropylthioxanthone, marketed as
SPEEDCURE ITX and referred to herein also as ITX, 9,10-Dibutoxy
anthracene marketed as Anthracure.RTM. UVS-1331, Phenothiazine (253
and 318 nm), Anthracene, and a curcumin compound such as marketed
as Ecocol curcumin colour 95%
[0549] Table 2 below presents a list of exemplary components which
can be included, in any combination, in a UV-curable non-ROMP
system as described herein in any one of the embodiments and any
combinations thereof. In embodiments pertaining to a dual jetting
methodology, the components can be included in one or more modeling
material formulations, as described herein.
TABLE-US-00004 TABLE 2 Trade Name Chemical Type Function Supplier
SR423A Isobornyl methacrylate Free radical Sartomer Oligomer SR-843
Tricyclodecane Free radical Sartomer dimethanol Monomer
dimethacrylate SR-351 Trimethylol propane Free radical Sartomer
triacrylate bifunctional monomer (Cross-linker) PHOTOMER Bis Phenol
A Free radical Cognis 4028F Ethoxylated Acrylic oligomer Diacrylate
(bifunctional) SR506D Isobornyl acrylate Free radical Sartomer
Acrylic oligomer SR833S Tricyclodecane Free radical Sartomer
dimethanol diacrylate Acrylic oligomer EBECRYL Silicon acrylated
Phase separation UCB 350 oligomer promoter Chemicals UVCURE
P-(octyloxyphenyl) Cationic CYTEC 1600 phenyliodonium
photoinitiator hexafluoroantimonate IGRACURE Alpha, alpha-dimethoxy
Free radical CIBA I-651 alpha photoinitiator phenylacetophenone
Uvacure 1500 Cycloaliphatic epoxide Cationic Cytec monomer TPO
Diphenyl (2,4,6 Free radical BASF trimethylbenzoyl) photoinitiator
phosphine oxide BR 970 Urethane diacrylate Free radical IGM Acrylic
oligomer SPEEDCURE 2-isopropylthioxanthone Cationic LAMBSON ITX and
photo sensitizer 4-isopropylthioxanthone BYK 3570 Acrylfunctional
Additive BYK polyester modified polydimethlsiloxane CURCUMIN
1,6-Heptadiene-3,5- Cationic AXOWIN dione, 1,7-bis(4-
photosensitizer hydroxy-3- methoxyphenyl)- DBS-C21 Carbinol
Toughening GELEST hydroxyterminated agent PDMS
[0550] The First and Second Modeling Material Formulations:
[0551] According to some of any of the embodiments described
herein, the building material formulation comprises at least a
first and a second modeling material formulations, which react with
one another to form the modeling material.
[0552] It is to be noted that more than two modeling formulations
can be included in the building material formulation, and that at
least two of these formulations, and optionally three or more of
these formulations, react with one another to form the modeling
material.
[0553] In some of any of the embodiments described herein, the
first modeling material formulation comprises a first material,
which is referred to herein as a first ROMP monomer. Any of the
ROMP monomers described herein and in the art are contemplated.
[0554] In some of any of the embodiments described herein, the
second modeling material formulation comprises at least a second
material that reacts with the ROMP monomer so as to form a cured
model material when exposed to a curing condition (e.g., a ROMP
inducing condition as described herein).
[0555] By "reacting" and grammatical diversion thereof, it is meant
that two or more substances in the compositions interact with one
another physically and/or chemically, while forming the building
material. The term "reacting" and grammatical diversions is also
referred to herein interchangeably as "interacting" and
corresponding grammatical diversions thereof.
[0556] The interaction can thus be, for example, a physical
interaction such as physical absorption, entanglement,
incorporation or any other interaction that leads to a form in
which two or more substances are interconnected. For example, one
substance can form a polymeric network and the other substance can
be entangled with or incorporated within the network.
Alternatively, both substances can form polymeric networks which
are intermixed with one another.
[0557] The interaction alternatively or in addition can be a
chemical interaction, in which two or more substances in the
formulations undergo a chemical reaction that leads to a bond
formation. The bond can be an ionic bond, a hydrogen bond, or a
covalent bond, and is preferably a covalent bond.
[0558] In some of any of the embodiments described herein, the
interaction comprises a chemical reaction, such that at least the
first ROMP monomer and the second material, and optionally other
components in one or more of the formulations, chemically react
with one another.
[0559] In some of any of the embodiments described herein, the
interaction occurs once the first and second compositions are being
contacted with one another.
[0560] By "being contacted" it is meant that the first and second
formulations are in a proximity that enables a chemical reaction
between two or more substances in the compositions to occur. An
exemplary suitable proximity, in the context of the present
embodiments, is, for example, of adjacent voxels within a layer of
dispensed drops, and/or of drops deposited one onto (on top of) the
other within the same voxel of a layer.
[0561] For example, by forming one or more voxels of the first
model formulation and one or more adjacent voxels of the second
model formulation, the first and second model formulations are
contacted and an interaction (e.g., a chemical reaction)
occurs.
[0562] In some of any of the embodiments described herein, the
interaction (e.g., chemical reaction) occurs upon exposure to a
curing condition, as defined herein.
[0563] In some of any of the embodiments described herein, the
first model formulation comprises at least a first material which
is a first ROMP monomer and the second model formulation comprises
at least a second material, and the second material interacts
(e.g., chemically reacts) with the first ROMP monomer to form the
building (e.g., modeling) material upon being contacted and exposed
to curing condition.
[0564] In some of any of the embodiments described herein, the
ratio between materials included in the first model formulation
(e.g., a first ROMP monomer) and materials included in the second
model formulation (e.g., a second material), which interact (e.g.,
chemically react) to form a building (e.g., modeling) material,
determines the chemical composition of a building material.
[0565] By selecting a ratio of the number of voxels of the first
model formulation and the number of voxels of the second model
formulation, in a voxel block where the first and second model
formulations are dispensed and react, a chemical composition of the
building material is determined. Selecting different ratios of the
first and the second model formulations, and thus of the first and
second materials, for each voxel block, results in building
materials of different chemical compositions in each voxel
block.
[0566] This enables obtaining a printed object in which at least
two, and preferably much more, voxel blocks exhibit different
properties, such as chemical properties, mechanical properties,
thermal properties, optical properties, as described in further
detail hereinbelow, based on the selected ratio.
[0567] It is to be noted that embodiments where one or both model
formulations comprise both a first material and a second material
that interact (e.g., chemically react) with one another to form the
(cured) building (e.g., modeling) material are also contemplated.
In some of these embodiments, the first and second materials do not
react, or react slowly, with one another, without the presence of
an additional material, in which case only one of the compositions
further comprises such an additional material. Alternatively, in
some of these embodiments, the first and second materials do not
react, or react slowly, with one another, without being subjected
to conditions that effect the reaction (e.g., a curing condition,
as described herein, and/or a condition that induces a ROMP
reaction, as described herein). In these embodiments, a ratio of
the first and second materials in each model formulation is
considered for selecting a ratio of the first and second model
formulations.
[0568] In some of any of the embodiments described herein, one or
both of the first and second model formulations comprises a curable
material, which may form a building material upon being exposed to
a curing condition.
[0569] The curable material comprises at least one ROMP monomer
that undergoes ROMP when exposed to a condition that induces
initiation of ROMP, as described herein, and the product of the
curing, which is or forms a part of the cured modeling material is
a polymer (a ROMP polymer) obtained by the ROMP of the at least one
ROMP monomer.
[0570] In some of any of the embodiments described herein, the
first model formulation comprises a first material which is a first
ROMP monomer as described herein. In some embodiments, the first
ROMP monomer can be used per se for forming a modeling material,
when subjected to suitable conditions as described herein,
optionally in the presence of catalysts and/or activators, as
described herein in any of the respective embodiments.
[0571] In some of any of the embodiments described herein, the
second modeling formulation comprises a second material, which
participates in the ROMP in which a modeling material or a part
thereof is formed of the first ROMP monomer.
[0572] In some embodiments, the second material, by chemically
reacting with the first ROMP monomer, as defined herein, forms a
part of the cured modeling material that is formed of the first
ROMP monomer, when the first and second materials are exposed to a
curing condition (e.g., a ROMP inducing condition) as described
herein.
[0573] In some of any of the embodiments described herein, the
second material is selected as being capable of modifying a
property (e.g., a chemical, physical, thermal and/or mechanical
property) of a modeling material formed of the first material, when
chemically reacting with the first material upon exposure to a
curing condition.
[0574] That is, a modeling material formed as a result of a
chemical reaction between the first and the second materials has at
least one property that is different from a respective property of
a modeling material formed upon curing only the first ROMP monomer.
This property may also depend on the ratio of the first and second
materials participating in the reaction.
[0575] In some embodiments, the different property is not a result
of a physical mixture of the two compositions but rather a result
of a chemical reaction that occurs between the first and the second
model formulations upon contacting one another and being exposed to
a curing condition. The different property may be a result of the
chemical reaction or a result of a physical interaction with
another substance included in one or both formulations.
[0576] It is to be further noted that both the first and second
model formulations are preferably exposed to the same curing
condition under which the chemical reaction occurs. However,
different curing conditions, or curing energies, or a combination
of curing energies, is also contemplated, as described herein.
[0577] It is to be further noted that in some embodiments,
subjecting the first and second model formulations, including at
least the first and second materials, to an interaction (e.g., a
chemical reaction), upon contacting the model formulations and
exposure to a curing condition, results in a polymeric material,
which is different from a polymeric material that is formed when
each of the model formulations is subjected alone to the curing
condition, even if such polymeric materials are physically mixed.
That is, for example, the second material interacts with the first
material when both are subjected to the same curing condition, and
the obtained polymeric material is different from a polymeric
material formed upon curing a first material, a polymeric material
formed upon curing a second material, and/or a physical mixture of
such polymeric materials. The polymeric material structure and/or
properties also depend on the ratio between the materials getting
in contact and exposed to curing energy.
[0578] As described herein, selecting a ratio of the first and
second model formulations determines a chemical composition of the
building (e.g., modeling) material within a voxel block.
[0579] A property of the modeling material which is modified by the
second material, at a voxel level, can be, for example, a
mechanical property, a physical property or a chemical
property.
[0580] Mechanical properties which can be modified by the second
material include, for example, elasticity, elongation at fracture,
toughness, impact resistance at ambient temperature and/or at a low
temperature, Shore hardness, heat deflection temperature (HDT),
tear resistance, tensile strength, impact strength, flexural
strength, creep resistance, and any additional mechanical property
relevant to the formed building (e.g., modeling) material, as would
be readily recognized by those skilled in the art.
[0581] Physical properties which can be modified by the second
material include, for example, optical activity, light absorbance
or transmittance, conductivity, crystallinity, phase transition
temperature (e.g., Tm), and any additional physical property
relevant to the formed building (e.g., modeling) material, as would
be readily recognized by those skilled in the art.
[0582] Chemical properties which can be modified by the second
material include, for example, hydrophobicity, hydrophilicity,
chemical reactivity, solubility, adhesion, surface roughness, and
any additional physical property relevant to the formed building
(e.g., modeling) material, as would be readily recognized by those
skilled in the art.
[0583] In some of any of the embodiments described herein, the
degree by which a property of the modeling material is modified
(with respect to a modeling material made of only the first
material) is determined by selecting the ratio between the first
and second model formulations, and hence between the first and
second materials.
[0584] For example, when a first material interacts with a second
material to form a modeling material that has a higher elasticity
compared to a modeling material formed of the first material in the
absence of the second material, the ratio between the first and the
second modeling formulations determines the degree of elasticity of
the (cured) modeling material, at a selected voxel block.
[0585] In another example, when a first material interacts with a
second material to form a modeling material that has a higher
elasticity compared to a modeling material formed of the first
material in the absence of the second material, the ratio between
the first and the second modeling formulations determines the
degree of elasticity of the (cured) modeling material, at a
selected voxel block.
[0586] In another example, when a first material interacts with a
second material to form a modeling material that has a higher
Impact resistance compared to a modeling material formed of the
first material in the absence of the second material, the ratio
between the first and the second model formulations determines the
Impact resistance of the (cured) modeling material, at a selected
voxel block.
[0587] In another example, when a first material interacts with a
second material to form a modeling material that has a higher
toughness (as described herein) compared to a modeling material
formed of the first material in the absence of the second material,
the ratio between the first and the second model formulations
determines the toughness of the (cured) modeling material, at a
selected voxel block.
[0588] In some of any of the embodiments described herein, the
second material is selected capable of modifying a chemical,
physical and/or mechanical property of a (cured) modeling material
formed of the first ROMP monomer, upon interacting (e.g.,
chemically reacting) with the first ROMP monomer and exposure to a
curing condition, as described herein. The degree of the
modification is determined by the selected ratio.
[0589] In some of any of the embodiments described herein, the
second material comprises a moiety which is such that when forming
a part of a modeling material formed of the first ROMP monomer, a
chemical, physical and/or mechanical property, as defined herein,
of the (cured) modeling material is modified. The degree of the
modification is determined by the selected ratio.
[0590] Such a moiety can be or can comprise a toughening moiety (a
toughness modifying moiety), an impact modifying moiety, an
elastomeric moiety, and optically-active moiety, a light-absorbing
moiety, a hydrophobic moiety, a hydrophilic moiety and/or a
chemically-reactive moiety, as these are described herein.
[0591] Each of the first and second modeling material formulations
may comprise additional materials, which may or may not form a part
of the (cured) building (e.g., modeling) material formed upon
contacting the first and second model formulations. Such additional
materials may participate in the interaction that forms the (cured)
building (e.g., modeling) material. Alternatively, such additional
materials induce the chemical reaction, yet may not form a part of
the (cured) building (e.g., modeling) material. Exemplary such
materials include, but are not limited to, catalysts, activators,
inhibitors, initiators, pH-adjusting agents, and the like.
[0592] In some of any of the embodiments described herein, one or
both of the first and second model formulations further comprises a
second ROMP monomer, which is different from the first ROMP
monomer.
[0593] In some of these embodiments, the first and second ROMP
monomers chemically react, by co-polymerization, to form a modeling
material which is or comprises a ROMP copolymer.
[0594] In some of these embodiments, the second ROMP monomer is a
bi-functional or multi-functional ROMP monomer, as described
herein. Such ROMP monomers can effect cross-linking of polymeric
chains formed of, e.g., ROMP monomers, and thereby affect a
property of the modeling material.
[0595] In some of these embodiments, the first ROMP monomer is a
mono-functional monomer. However, the first ROMP monomer can also
be di-functional or tri-functional, and reacting the first and
second monomers may modify the cross-linking degree of the
resulting polymeric material (cured modeling material).
[0596] In some of any of these embodiments, the second ROMP monomer
is a second material as described herein, which modifies a property
of the modeling material when chemically reacting with the first
ROMP monomer, for example, for affecting cross-linking or modifying
a cross-linking degree.
[0597] Alternatively or in addition, in some embodiments, the
second ROMP monomer is the second material, and comprises a moiety
that is capable of modifying a property of the modeling material
formed of the first ROMP monomer. For example, the second ROMP
monomer can be an unsaturated cyclic olefin, as described herein in
any of the respective embodiments, which is substituted by,
terminated with, or otherwise comprises, for example, an impact
modifying moiety, a hydrophobic moiety, an elastomeric moiety, an
optically active moiety, or any other moiety as described
herein.
[0598] In some of any of the embodiments when the first and second
materials are ROMP monomers, a chemical reaction between the first
and second materials, namely, co-polymerization, occurs between the
first and second model formulations.
[0599] In some of these embodiments, a mixture of ROMP monomers (or
oligomers) is used to form the modeling material such that the
latter is or comprises a co-polymer composed of this mixture of
monomers, e.g., composed of repeating backbone units derived from
one type of monomer (or oligomer) and repeating backbone units of
another type of monomer (or oligomer), covalently linked
therebetween in any order. A chemical composition of such a
co-polymer is determined by the molar ratio of each of the ROMP
monomers when polymerization occurs.
[0600] In some embodiments, the first material comprises a first
plurality of a first ROMP monomer and the second material comprises
a second plurality of a second ROMP monomer which is chemically
different from the first ROMP monomer, as described herein. When
contacted and exposed to a suitable curing condition, the first and
second pluralities of monomers chemically react with one another to
form a co-polymeric modeling material.
[0601] When the two model formulations chemically react, the
modeling material is formed via co-polymerization of the
monomers.
[0602] In exemplary embodiments, the second ROMP monomer is more
hydrophobic compared to the first ROMP monomer, thus modifying the
hydrophobicity of the building material.
[0603] For example, the second ROMP monomer may be substituted by a
hydrophobic moiety, whereby the hydrophobic moiety does not
participate in the ROMP when exposed to curing condition. When
contacting such a second ROMP monomer as a second material with a
first ROMP monomer which does not have a hydrophobic moiety,
exposing to curing condition, and selecting a ratio of the first
and second model formulations, the hydrophobicity of the co-polymer
that forms the modeling material can be digitally controlled.
[0604] For example, the second ROMP monomer may be substituted by,
or otherwise comprise, an elastomeric moiety, whereby the
elastomeric moiety does not participate in the ROMP when exposed to
curing condition. When contacting such a second ROMP monomer as a
second material with a first ROMP monomer which does not have an
elastomeric moiety, exposing to curing condition, and selecting a
ratio of the first and second model formulations, the
elasticity/toughness of the co-polymer that forms the modeling
material can be digitally controlled.
[0605] In exemplary embodiments, a second ROMP monomer is a
multifunctional ROMP monomer which affects a cross-linking degree
of the co-polymer and thereby affects a stiffness of the
polymer.
[0606] Similarly, the second ROMP monomer may be substituted by a
chemically-reactive group, or a conductive group (e.g., a charged
group), or a hydrophilic group, or a light-absorbing group, as
defined herein, such that selecting a ratio of the first and second
model formulations results in modifying a respective property of a
modeling material made of the first curable material.
[0607] In alternative embodiments, a mixture of ROMP monomers is
used to form the modeling material, whereby a polymerized material
formed of at least one of the ROMP monomers interacts with a
polymerized material formed of another ROMP monomer by
cross-linking. A chemical composition of such a co-polymer is
determined by the molar ratio of each of the ROMP monomers when
polymerization occurs.
[0608] In exemplary embodiments, a polymer formed of the first ROMP
monomer is cross-linked by the second ROMP monomer, or a polymer or
oligomer formed therefrom, upon exposing to a suitable curing
condition. Such cross-linking modifies one or more of the chemical,
physical and mechanical properties of a modeling material formed of
the first ROMP.
[0609] When contacting such first and second materials, exposing to
suitable curing condition, and selecting a ratio of the first and
second model formulations, various properties of the obtained
modeling material can be digitally controlled.
[0610] In some of any of the embodiments described herein, the
second material is a non-ROMP material, namely, it is not a cyclic
unsaturated material as described herein, but it comprises an
unsaturated moiety that can interact (e.g., chemically react) with
a ROMP monomer during a ROMP reaction, and form a part of the
polymeric material formed upon exposure to a curing condition
(e.g., a ROMP inducing condition).
[0611] Such a material is also referred to herein as a ROMP
reactive material.
[0612] In some embodiments, the second material is a ROMP reactive
material which comprises a moiety that modifies a property of a
ROMP polymer made of the first ROMP monomer.
[0613] Exemplary such second materials include elastomeric
materials as described in further detail hereinbelow, such as, but
not limited to, ethylene propylene rubber (EPR), ethylene propylene
diene monomer (EPDM), Trilene 77, Trilene 67, and similar
elastomeric compounds, featuring one or more vinyl or diene
group(s) that can participate in a ROMP reaction.
[0614] In some of any of the embodiments described herein, at least
one of the first and second modeling material formulations further
comprises a catalyst for initiating ROMP, for example, ROMP of the
first ROMP monomer or of a first and second ROMP monomers as
described herein, according to any one of the respective
embodiments described herein for a ROMP catalyst system and any
combination thereof.
[0615] In some of any of the embodiments described herein, prior to
exposing to the curing condition the catalyst does not initiate
ROMP of the ROMP monomer(s).
[0616] The catalyst may be an active catalyst, a latent catalyst or
a pre-catalyst, as described herein, and the ROMP monomer(s) and
the catalyst can be included accordingly in the first and second
formulations, as described herein for any of the respective
embodiments of the model formulations comprising a ROMP system (for
example, for a dual- or multi-jetting, single curing
formulations).
[0617] In some embodiments, the first modeling formulation further
comprises a ROMP catalyst, and the catalyst is activatable by the
curing condition, as described herein.
[0618] In some embodiments, the catalyst is activatable by an
activator, and at least one of the modeling material formulations
comprises the activator and is devoid of the catalyst, as described
herein.
[0619] In some embodiments, the first modeling material formulation
comprises the first ROMP monomer and the activator and is
preferably devoid of a pre-catalyst and the second modeling
material formulation comprises the pre-catalyst, as described
herein, and is preferably devoid of the activator.
[0620] In some embodiments, the first modeling material formulation
comprises the first ROMP monomer and the pre-catalyst, and is
preferably devoid of an activator, and the second modeling material
formulation comprises the activator, as described herein, and is
preferably devoid of a pre-catalyst.
[0621] In some of any of the embodiments described herein, at least
one of the first and second modeling material formulations further
comprises a ROMP inhibitor, as described herein.
[0622] In some of any of the embodiments described herein, at least
one of the first and second modeling material formulations further
comprises at least one non-ROMP material polymerizable or curable
via a non-ROMP reaction, as described herein.
[0623] The first and second formulations according to these
embodiments can be in accordance with any of the respective
embodiments described herein for dual or multi-jetting, dual- or
multi-curing.
[0624] In some of these embodiments, the curing condition further
comprises a condition for inducing polymerization or curing of the
at least one non-ROMP material.
[0625] In some of these embodiments, the non-ROMP material
comprises a monomer and/or an oligomer polymerizable by
free-radical polymerization, cationic polymerization, anionic
polymerization, or polycondensation.
[0626] In some of these embodiments, the non-ROMP material is
polymerizable or curable upon exposure to irradiation
(photopolymerizable).
[0627] In some of these embodiments, at least one of the first and
second modeling material formulations further comprises an
initiator of the non-ROMP reaction.
[0628] In some of these embodiments, the initiator is comprised in
at least one modeling material formulation which is devoid of the
material polymerizable or curable via the non-ROMP reaction.
[0629] In some of any of these embodiments, the second material is
the non-ROMP material polymerizable or curable via a non-ROMP
reaction, as described herein.
[0630] The second material, according to these embodiments, forms a
polymeric material that is different from the polymeric material
formed of the first ROMP material, alone or in combination with
other ROMP monomers (e.g., a second ROMP monomer, as described
herein).
[0631] The physical interaction between these polymeric materials
may modify a property of a modeling material of ROMP monomer or
monomers, and the selected ratio determines the degree of the
modification at the voxel level, as described herein.
[0632] In some embodiments, the non-ROMP curable material comprises
a moiety that is capable of modifying the property, as described
herein.
[0633] In some of any of these embodiments, the first and second
formulations comprise a ROMP system and an additional curable
system, as described herein in any of the respective
embodiments.
[0634] In some of any of the embodiments described herein, the
first material, as defined herein, forms the modeling material by
reacting with a second material that is not a curable material.
[0635] In these embodiments, the curing of the first material
occurs in the presence of the second material, and the second
material forms a part of the modeling material, optionally by a
physical interaction with the polymeric material formed of the
first ROMP monomer or monomers, and optionally of non-ROMP curable
materials, if present in one or both model formulations, as
described herein.
[0636] In some embodiments, by interacting with the first material,
or with a polymeric material formed therefrom, the second material
forms a part of the modeling material obtained upon exposing the
first material to curing condition.
[0637] In some of these embodiments, the first model formulation
comprises the first material, as described herein (a first ROMP
monomer), and another model formulation (e.g., the second model
formulation) comprises the second material. The first and/or second
formulation can further comprise any of the additional components
(e.g., catalysts, activators, non-ROMP curable materials,
initiators, or any other components of a curable system, as
described herein in any of the respective embodiments).
[0638] By selecting the ratio of the first and second model
formulations, and thus the ratio of the first material and the
second material, for each voxel block, the property or properties
imparted or modified by the second material is determined, and
different modeling materials which exhibit a different degree of
such property or properties, are obtained, for each voxel
block.
[0639] In exemplary embodiments, the second material comprises a
moiety such as, for example, an elastomeric moiety, an impact
modifying moiety, an optically-active moiety, a light-absorbing
moiety, a hydrophobic moiety, a hydrophilic moiety and/or a
chemically reactive moiety.
[0640] In exemplary embodiments, the second material is or
comprises a non-curable material that is capable of modifying one
or more of the chemical, physical and mechanical properties
described herein, by interacting with the first ROMP monomer or a
polymeric material formed therefrom, optionally in combination with
any of the other monomers or curable systems as described
herein.
[0641] The non-curable materials can be, for example, fillers,
pigments, dyes and/or toughening agents or toughness modifiers
(e.g., impact modifying agents).
[0642] The non-curable material can interact with the polymeric
material formed of at least the first ROMP monomer, and optionally
of any other curable material in the first and second formulations
by physical interactions as described herein.
[0643] The term "filler" describes an inert material that modifies
the properties of a polymeric material and/or adjusts a quality of
the end products. The filler may be an inorganic particle, for
example calcium carbonate, silica, and clay.
[0644] Fillers may be added to the modeling formulation in order to
reduce shrinkage during polymerization or during cooling, for
example, to reduce the coefficient of thermal expansion, increase
strength, increase thermal stability, reduce cost and/or adopt
rheological properties. Nanoparticles fillers are typically useful
in applications requiring low viscosity such as ink-jet
applications.
[0645] The pigment may be a white pigment. The pigment may be an
organic pigment or an inorganic pigment, or a metal pigment or a
combination thereof.
[0646] In some embodiments, combinations of white pigments and dyes
are used to prepare colored cured materials.
[0647] The dye may be any of a broad class of solvent soluble dyes.
Some non-limiting examples are azo dyes which are yellow, orange,
brown and red; anthraquinone and triarylmethane dyes which are
green and blue; and azine dye which is black.
[0648] In some embodiments, one or more of the modeling material
formulations comprises an antioxidant. In some embodiments, at
least a modeling material formulation that comprises a ROMP
catalyst comprises an anti-oxidant.
[0649] In some embodiments, one or more, or each, of the modeling
material formulations comprises a proton donor. Proton donors are
useful for accelerating the activation of a pre-catalyst by the
activator, to thereby accelerate the ROMP reaction, in case such a
catalyst is used. For example, a proton donor, when contacted with
a chlorosilane activator as described herein generates HCl, which
accelerates the activation of the pre-catalyst.
[0650] The proton donors can be reactive (curable) or non-reactive.
Curable proton donors include, for example, ROMP monomers which
bear acidic protons (e.g., hydroxy groups).
[0651] An exemplary proton donor is a hydroxy alkyl, for example,
1-butanol.
[0652] A concentration of the proton donor can range from about 0.1
to about 2%, by weight, of a modeling material formulation
containing same, including any intermediate values and subranges
therebetween.
[0653] According to some embodiments of the present invention, the
non-curable material is or comprises a toughening agent.
[0654] The toughening agent, according to some embodiments, can be
added to one or more (e.g., two) of the modeling material
formulations.
[0655] The phrase "toughening agent" is also referred to herein as
a "toughness modifying agent" or "toughness modifier" and
encompasses one or more (e.g., a mixture of two or more) toughening
agents and is used herein to describe agents that modify (e.g.,
improve) the toughness of a material containing same.
[0656] In some embodiments, the toughness is reflected by Impact
resistance and/or tensile strength.
[0657] In some embodiments, a toughness modifying agent (a
toughening agent) improves the Impact resistance and/or Tensile
strength of a material containing same. In some embodiments, a
toughness modifying agent (a toughening agent) improves the Impact
resistance of a material containing. In some embodiments, a
toughness modifying agent (a toughening agent) improves the Tensile
strength of a material containing same. In some embodiments, a
toughness modifying agent (a toughening agent) improves the Impact
resistance and the Tensile strength of a material containing
same.
[0658] The phrase "toughening agent" encompasses materials referred
to herein as "Impact modifying agents" or "Impact modifiers".
[0659] According to some of any of the embodiments of the present
invention, the toughening agent (e.g. Impact modifying agent) is an
elastomeric material.
[0660] The phrase "elastomeric material" is also referred to herein
and in the art interchangeably as "elastomer" and encompasses
deformable, viscoelastic polymeric materials (typically
co-polymers), including rubbers, liquid rubbers and rubbery-like
materials.
[0661] In some embodiments, an elastomeric material as described
herein comprises saturated and/or unsaturated hydrocarbon chains,
preferably long hydrocarbon chains of at least 20 carbon atoms in
length. In some embodiments, the hydrocarbon chains do not include
heteroatoms (e.g., oxygen, nitrogen, sulfur) interrupting the chain
or forming a part of the substituents of the chain.
[0662] In some embodiments, by "hydrocarbon" it is meant herein a
material containing one or more chains comprised mainly (e.g., 80%,
or 85% or 90%, or 95%, or 100%) of carbon and hydrogen atoms,
linked to one another. Exemplary hydrocarbons include one or more
alkyl, cycloalkyl and/or aryl moieties covalently linked to one
another at any order.
[0663] Non-limiting examples of toughening agents include
elastomeric materials such as, but not limited to, natural rubber,
butyl rubber, polyisoprene, polybutadiene, polyisobutylene,
ethylene-propylene copolymer, styrene-butadiene-styrene triblock
rubber, random styrene-butadiene rubber, styrene-isoprene-styrene
triblock rubber, styrene-ethylene/butylene-styrene copolymer,
styrene-ethylene/propylene-styrene copolymer,
ethylene-propylene-diene terpolymers, ethylene-vinyl acetate and
nitrile rubbers. Preferred agents are elastomers such as
polybutadienes.
[0664] Toughening agents such as elastomeric materials can be added
to the formulation by incorporating in one or more of the modeling
material formulations an elastomeric material in a
dispersed/dissolved phase.
[0665] As demonstrated and discussed in the Examples section that
follows, the present inventors have shown that the addition of a
toughening agent provides for substantially improved mechanical
properties (e.g., Impact resistance). The present inventors have
further identified some characteristics of a toughening agent,
which results in enhanced improvement in the mechanical properties
and improved suitability to 3D inkjet printing of ROMP
materials.
[0666] According to some of any of the embodiments described
herein, the elastomeric material is characterized by at least one,
at least two, or all of the following:
[0667] featuring a molecular weight lower than 50,000, or lower
than 40,000, or, preferably, lower than 30,000, or lower than
20,000, or lower than 10,000 Daltons;
[0668] being non-reactive towards ROMP;
[0669] being dissolvable or dispersible in the one or more modeling
material formulation(s) containing same; and
[0670] being capable of forming a multiphase (e.g., biphasic)
structure when blended with the cured modeling material.
[0671] According to some of any of the embodiments described
herein, the elastomeric material is dissolvable or dispersible in
the modeling material formulation comprising same.
[0672] Depending on the methodology, the modeling material
formulation comprising the elastomeric material may comprise a ROMP
monomer and/or a non-ROMP monomer.
[0673] ROMP monomers and formulations containing same are typically
hydrophobic. Therefore, in some embodiments, the elastomeric
material is selected as dissolvable or dispersible in a modeling
material formulation which comprises a ROMP monomer. In some
embodiments, the elastomeric material is hydrophobic, and thereby
exhibits compatibility, and dissolvability or dispersibility in the
ROMP monomer formulation, which has a hydrophobic nature. In other
embodiments, the elastomeric material is selected dissolvable or
dispersible in a formulation which comprises, in addition to, or
instead of, the ROMP monomer, a non-ROMP curable material as
described herein in any of the respective embodiments.
[0674] According to some of any of the embodiments described
herein, the elastomeric material is selected capable of forming a
multiphase (e.g., biphasic) structure when blended with the cured
modeling material.
[0675] As explained in the Examples section that follows and is
known in the art, Impact resistance can be improved in case of a
phase separation between the impact modifying agent and the
polymeric matrix with which it is blended, namely, in case where
there is a biphasic or multiphasic structure of the blend.
[0676] In some embodiments, an elastomeric material that is capable
of forming a multiphase (e.g., biphasic) structure when blended
with the cured modeling material can be regarded as non-soluble in
the polymeric matrix formed upon exposing the modeling material
formulation(s) to curing condition, namely, in the cured (or
partially cured) modeling material.
[0677] According to some of any of the embodiments described
herein, the elastomeric material is selected such that it is
dissolvable or dispersible in the modeling material comprising
same, and is further capable of forming a multiphase (e.g.,
biphasic) structure when blended with the cured modeling
material.
[0678] In some of the embodiments pertaining to an elastomeric
material that is capable of forming a multiphasic structure when
blended with the cured modeling material, the ROMP monomer is or
comprises a DCPD or a derivative thereof, as described herein.
[0679] It is to be noted that phase separation is not required for
an Impact modifying agent to provide its effect in all cases. That
is, when an elastomeric material is blended with a cured modeling
material formed of a ROMP monomer-containing modeling material
formulation(s), Impact resistance can be improved also when there
is no phase separation (no biphasic or multiphasic structure is
formed).
[0680] According to some of any of the embodiments described
herein, the elastomeric material is non-reactive towards ROMP. By
"non-reactive towards ROMP" it is meant that the elastomeric
material does feature functional groups that can participate in
ROMP. As known in the art, ROMP involves materials featuring
unsaturated bonds. Accordingly, exemplary elastomeric materials
which are non-reactive towards ROMP are saturated polymeric
materials, namely, polymers and/or copolymers which do not comprise
unsaturated bonds in their backbone chain. The pendant groups of
such elastomeric materials may or may not comprise unsaturated
bonds.
[0681] Elastomeric materials featuring a saturated backbone chain,
namely, are devoid of unsaturated bonds in their backbone chain,
are defined herein as "saturated" elastomeric materials.
[0682] In some of the embodiments pertaining to an elastomeric
material that is non-reactive towards ROMP, the ROMP monomer is or
comprises a DCPD or a derivative thereof, as described herein.
[0683] According to some embodiments of the present invention, the
elastomeric material is a low molecular weight material, as defined
herein, which is a saturated polymer or co-polymer.
[0684] According to some embodiments of the present invention, the
elastomeric material is a low molecular weight material, as defined
herein, which is hydrophobic.
[0685] According to some embodiments of the present invention, the
elastomeric material is a low molecular weight material, as defined
herein, which is a saturated polymer or co-polymer and which is
further characterized as hydrophobic.
[0686] According to some of these embodiments, the elastomeric
material is further characterized as dissolvable or dispersible in
the modeling material formulation containing same and optionally
further as forming a biphasic structure with the cured modeling
material.
[0687] Non-limiting examples of elastomers usable as toughening
agents according to the present embodiments include low molecular
weight EPR elastomers, and low molecular weight polybutenes.
Exemplary elastomeric materials suitable for use according to some
of the present embodiments include, but are not limited to, low MW
EPDM such as Trilene 67 (MW=37,000 Da) or Trilene 77 (MW=27,000
Da), liquid EPR elastomers such as Trilene CP80 (MW=23,000 Da) or
Trilene CP1100 (MW=6600 Da), low MW polybutenes, low MW
polyisoprenes, and the like. Preferred exemplary elastomeric
materials include, but are not limited to, liquid EPR elastomers
and polybutenes, having MW lower than 20,000 or lower than 12,000
Daltons. Non-limiting examples of elastomers usable as toughening
agents according to the present embodiments are presented in Table
5 hereinbelow.
[0688] According to some of any of the embodiments, a concentration
of the toughening agent (e.g., an elastomeric material as described
herein) may range from about 0.1% to about 20%, or from about 1 to
about 20%, or from about 1 to about 15%, or from about 1 to about
12%, or from about 1 to about 10%, or from about 2 to about 10%, or
from about 2 to about 8%, by weight, of the total weight of a
formulation containing same, including any intermediate values and
subranges therebetween.
[0689] A concentration of the toughening agent (e.g. elastomeric
materials as described herein), may range from about 0.10 phr to
about 10 phr, or from about 0.1 phr to about 5 phr, relative to the
weight of the formulation containing same.
[0690] A concentration of the toughening agent (e.g. elastomeric
material as described herein) may alternatively range from about
0.1% to about 20%, or from about 1% to about 20%, or from about 1%
to about 20%, or from about 5% to about 15% or from about 5% to
about 10%, by weight, of the total weight of a formulation
containing same, including any intermediate values and subranges
therebetween.
[0691] In some embodiments, each of the modeling material
formulations comprises an elastomeric material, as described
herein.
[0692] In some embodiments, the non-curable material is or
comprises other impact modifying agents, such as, for example,
carbon fibers, carbon nanotubes, glass fibers, aramid Keylar,
polyparaphenylene benzobisoxazole Zylon, and other polar and non
polar impact modifiers.
[0693] Alternatively, or in addition, elastomeric materials other
than the elastomeric materials described herein can be included. In
some embodiments, a concentration of such elastomeric materials, if
present, is lower than a concentration of the elastomeric materials
described herein.
[0694] By controlling the ratio of the first and the second model
formulations, the modeling material features variable degrees of
the property or properties imparted by these agents at the voxel
level, as described herein.
[0695] Alternatively, or in addition, one or more of the model
formulations can comprise one or more surface active agents,
stabilizers, and/or antioxidants.
[0696] In some embodiments, a modeling formulation comprises a
surface active agent. A surface-active agent may be used to reduce
the surface tension of the formulation to the value required for
jetting or for printing process, which is typically from about 10
to about 50 dyne/cm. An exemplary such agent is a silicone surface
additive.
[0697] Suitable stabilizers (stabilizing agents) include, for
example, thermal stabilizers, which stabilize the formulation at
high temperatures.
[0698] In some of any of the embodiments described herein, a
curable material other than a ROMP monomer forms a polymeric
material that comprises a polyester, a polycarbonate, a
polyurethane, a polyether urethane, a polyether carbonate, a
polyester carbonate, a polyester urethane, a polyanhydride, a
polyamide, a polyacid, and copolymers thereof.
[0699] Curable materials that form such polymeric materials upon
exposure to curing condition would be known to any person skilled
in the art.
[0700] In some of any of the embodiments described herein, the
curable materials are selected to form a polymeric (or
co-polymeric) material upon exposure to heat.
[0701] In some of any of the embodiments described herein, the
second material comprises a moiety (a component) that imparts or
modifies a property of the polymeric material made of a ROMP
monomer, as described herein.
[0702] In some embodiments, the property is a mechanical property
and in some embodiments, it is the toughness (e.g., impact
resistance and/or tensile strength. In these embodiments, the
second material can be regarded as a toughening agent, and the
ratio between the first and the second formulations determines a
toughness property of the modeling material at a voxel block.
[0703] In these embodiments, the second material can be regarded as
an impact modifying agent, and the ratio between the first and the
second formulations determines an impact resistance property of the
modeling material at a voxel block.
[0704] Herein throughout and in the art, the phrase "impact
resistance", which is also referred to interchangeably, herein and
in the art, as "impact strength" or simply as "impact", describes
the resistance of a material to fracture by a mechanical impact,
and is expressed in terms of the amount of energy absorbed by the
material before complete fracture. Impact resistance can be
measured using, for example, the ASTM D256-06 standard Izod impact
testing (also known as "Izod notched impact", or as "Izod impact"),
and is expressed as J/m.
[0705] In some embodiments, the property is a physical property and
in some embodiments, it is the heat deflection temperature.
[0706] Herein throughout and in the art, the phrase "heat
deflection temperature", or HDT, describes the temperature at which
a specimen of cured material deforms under a specified load.
Determination of HDT can be performed using the procedure outlines
in ASTM D648-06/D648-07.
[0707] As described herein, other moieties can be included in the
second material for affecting a property of the building material,
as described herein.
[0708] Optically-active moieties include, for example, moieties
that may rotate the plane of linearly polarized light about the
direction of motion as the light travels therethrough.
[0709] Light-absorbing moieties include, for example, chromophore
moieties, including dye moieties, fluorescent moieties,
phosphorescent moieties, and the light.
[0710] Conductance modifying moieties, referred to herein also as
conductive moieties, include, for example, conjugated moieties that
allow charge transfer therethrough.
[0711] Metal chelating moieties include moieties that can form
organometallic complexes with various metals or metal ions.
[0712] Hydrophobic moieties include hydrocarbon moieties, as
described herein, containing more than 4 carbon atoms, preferably
more than 6 carbon atoms, and more preferably more than 8 carbon
atoms.
[0713] Hydrophilic moieties include, for example, hydrocarbons, as
described herein, substituted by one, and preferably more, e.g., 2,
3, 4, 5, 6, 7, 8, 10, and even more, hydrophilic moieties such as
hydroxyl, carboxylic acid, amine, and the like. The inclusion of
hydrophilic moieties may affect the swelling properties of the
building material (e.g., a modeling material or a support
material).
[0714] Chemically-reactive moieties include, for example, moieties
or groups that readily react with another moiety or compound to
form a bond, as described herein. Such moieties allow for attaching
an additional material to selected portions of a printed
object.
[0715] Kits:
[0716] According to some of any of the embodiments described
herein, there are provided kits containing the modeling material
formulations as described herein. In some embodiments, a kit as
described herein is usable in a method as described herein.
[0717] In some embodiments, a kit comprises a modeling material
formulation system for use in a dual or multi-jetting methodology,
as described herein. The components of each of the modeling
material formulations (the first and second formulations, or Part A
and Part B) are packaged individually in the kit and include a ROMP
monomer or monomers, as described in any of the respective
embodiments, and other components of a ROMP system, as described
herein in any of the respective embodiments.
[0718] In exemplary embodiments, each of the first and the second
formulations as described herein is individually packaged in a
suitable packaging material, preferably, an impermeable material
(e.g., water- and gas-impermeable material), and further preferably
an opaque material; and both formulations are packaged together in
the kit. In some embodiments, the kit further comprises
instructions to use the formulations in an additive manufacturing
process, preferably a 3D inkjet printing process as described
herein. The kit may further comprise instructions to use the
formulations in the process in accordance with the method as
described herein. In some embodiments, the kits include
instructions to avoid contact between the first and second
formulations at any stage before printing is effected (e.g., before
the formulations are dispensed from the nozzles).
[0719] In some embodiments the kit comprises two or more modeling
material formulations, at least one of the formulations comprises a
ROMP monomer as described herein in any of the respective
embodiments.
[0720] In some of these embodiments, at least one of the
formulations further comprises a toughening agent as described
herein, and optionally further comprises a ROMP inhibitor, an
antioxidant and/or a proton donor. In some of these embodiments,
the toughening agent is an elastomer or an elastomeric material, as
described herein in any of the respective embodiments.
[0721] In exemplary embodiments, the first formulation comprises a
ROMP monomer as described herein (e.g., a RIM monomer), at a
concentration of from 50 to 99% or from 70 to 99%, by weight, and a
pre-catalyst as described herein (e.g., a mixture of two
pre-catalysts as described herein), at a concentration of from 0.01
to 0.1% by weight, and optionally further comprises a ROMP
inhibitor as described herein, at a concentration of 1 to 200 ppm,
or 1 to 60 ppm, as described herein, a toughening agent (e.g., an
elastomeric material as described herein) at a concentration of
from 0.1 to 20%, by weight, and/or an anti-oxidant, at a
concentration of 0.01-5%, by weight, and/or a filler as described
herein, at a concentration of 0.01-20% by weight, of the total
weight of the formulation.
[0722] In some of any of these embodiments, a second modeling
material formulation (also referred to herein as Part B) comprises
a ROMP monomer as described herein (e.g., a RIM monomer), which can
be the same or different from the ROMP monomer included in the
first formulation, and a ROMP activator (e.g., an organic
chlorosilane), as described herein in any of the respective
embodiments.
[0723] In some of these embodiments, the second formulation further
comprises a toughening agent as described herein. In some of these
embodiments, the toughening agent is an elastomer or an elastomeric
material, as described herein in any of the respective
embodiments.
[0724] In exemplary embodiments, the second formulation comprises a
ROMP monomer as described herein (e.g., a RIM monomer), at a
concentration of from 50 to 99% or from 70 to 99%, by weight, and a
ROMP activator as described herein (e.g., an organic chlorosilane),
at a concentration of from 0.01 to 2% by weight, and optionally
further comprises a toughening agent (e.g., an elastomeric material
as described herein) at a concentration of from 0.1 to 20%, by
weight, and/or a filler as described herein, at a concentration of
0.01-20% by weight, of the total weight of the formulation.
[0725] The Object:
[0726] According to an aspect of some embodiments of the present
invention there is provided a three-dimensional object, obtained by
a method as described herein in any of the respective embodiments
and any combination thereof. In some of these embodiments, the 3D
object is obtainable by 3D inkjet printing.
[0727] The 3D object is characterized by at least one portion in
which one voxel block exhibits a certain property or sets of
properties, and another voxel block exhibits a different property
or sets of properties. In some embodiments, the different property
is a different degree of the same property or set of properties,
for example, different toughness, different tensile strength,
different impact resistance, different HDT, different stiffness,
different elasticity, different chemical reactivity, etc.
[0728] Herein throughout, whenever the expression "at the voxel
level" is used in the context of a different material and/or
properties, it is meant to include differences between voxel
blocks, as well as differences between voxels or groups of few
voxels, and is preferably meant to include differences between
voxel blocks.
[0729] In some embodiments, the 3D object further comprises, in at
least a part thereof, a material featuring antioxidation, for
example, in a form of a layer deposited on the surface of the
object or a part thereof as described herein.
[0730] The Printing System:
[0731] FIG. 4 is a schematic illustration of a system 110 suitable
for 3D inkjet printing of an object 112 according to some
embodiments of the present invention. System 110 comprises a
printing apparatus 114 having a printing unit 116 which comprises a
plurality of printing heads. Each head preferably comprises an
array of one or more nozzles 122, as illustrated in FIGS. 8A-C
described below, through which a liquid (uncured) building material
124 is dispensed. Preferably, apparatus 114 is a three-dimensional
inkjet printing apparatus. FIGS. 8A-B illustrate a printing head
116 with one (FIG. 8A) and two (FIG. 8B) nozzle arrays 22. The
nozzles in the array are preferably aligned linearly, along a
straight line. In embodiments in which a particular printing head
has two or more linear nozzle arrays, the nozzle arrays are
optionally and preferably can be parallel to each other. In some
embodiments, two or more printing heads can be assembled to a block
of printing heads, in which case the printing heads of the block
are typically parallel to each other. A block including several
inkjet printing heads 116a, 116b, 116c is illustrated in FIG. 8C.
Printing heads 116 are optionally and preferably oriented along the
indexing direction with their positions along the scanning
direction being offset to one another.
[0732] Each printing head is optionally and preferably fed via a
building material reservoir which may optionally include a
temperature control unit (e.g., a temperature sensor and/or a
heating device), and a material level sensor. To dispense the
building material, a voltage signal is applied to the printing
heads to selectively deposit droplets of material via the printing
head nozzles, for example, as in piezoelectric inkjet printing
technology. The dispensing rate of each head depends on the number
of nozzles, the type of nozzles and the applied voltage signal rate
(frequency). Such printing heads are known to those skilled in the
art of solid freeform fabrication.
[0733] Preferably, but not obligatorily, the overall number of
printing nozzles or nozzle arrays is selected such that half of the
printing nozzles are designated to dispense support material
formulation(s) and half of the printing nozzles are designated to
dispense modeling material formulation(s), i.e. the number of
nozzles jetting modeling material formulations is the same as the
number of nozzles jetting support material formulations. In the
representative example of FIG. 4, four printing heads 116a, 116b,
116c and 116d are illustrated. Each of heads 116a, 116b, 116c and
116d has a nozzle array. In this Example, heads 116a and 116b can
be designated for modeling material/s and heads 116c and 116d can
be designated for support material. Thus, head 116a can dispense a
first modeling material formulation, head 116b can dispense a
second modeling material formulation and heads 116c and 116d can
both dispense a support material formulation. In an alternative
embodiment, heads 116c and 116d, for example, may be combined in a
single head having two nozzle arrays for depositing a support
material formulation.
[0734] Yet it is to be understood that it is not intended to limit
the scope of the present invention and that the number of modeling
material formulations depositing heads (modeling heads) and the
number of support material depositing heads (support heads) may
differ. Generally, the number of modeling heads, the number of
support heads and the number of nozzles in each respective head or
head array are selected such as to provide a predetermined ratio,
a, between the maximal dispensing rate of the support material and
the maximal dispensing rate of modeling material. The value of the
predetermined ratio, a, is preferably selected to ensure that in
each formed layer, the height of modeling material equals the
height of support material. Typical values for a are from about 0.6
to about 1.5.
[0735] For example, for a=1, the overall dispensing rate of support
material is generally the same as the overall dispensing rate of
the modeling material when all modeling heads and support heads
operate.
[0736] In a preferred embodiment, there are M modeling heads each
having m arrays of p nozzles, and S support heads each having s
arrays of q nozzles such that M.times.m.times.p=S.times.s.times.q.
Each of the M.times.m modeling arrays and S.times.s support arrays
can be manufactured as a separate physical unit, which can be
assembled and disassembled from the group of arrays. In this
embodiment, each such array optionally and preferably comprises a
temperature control unit and a material level sensor of its own,
and receives an individually controlled voltage for its
operation.
[0737] Apparatus 114 can further comprise a hardening device 324
which can include any device configured to emit light, heat or any
other curing energy that may cause the deposited material to
harden. For example, hardening device 324 can comprise one or more
radiation sources, which can be, for example, an infrared lamp or
any other source emitting heat-inducing radiation, as further
detailed hereinabove, a UV radiation source. In some embodiments of
the present invention, hardening device 324 serves for applying a
curing condition to the modeling material. The present embodiments
also contemplate configuration in which two different hardening
devices apply different types of curing energies, as further
detailed hereinabove.
[0738] The printing head and hardening devices are preferably
mounted in a frame or block 128 which is preferably operative to
reciprocally move over a tray 360, which serves as the working
surface. Apparatus 114 can further comprise a tray heater 328
configured for heating the tray. These embodiments are particularly
useful when the modeling material is hardened by heating (exposure
to heat).
[0739] In some embodiments of the present invention the radiation
sources are mounted in the block such that they follow in the wake
of the printing heads to at least partially cure or solidify the
materials just dispensed by the printing heads. Tray 360 is
positioned horizontally. According to the common conventions an
X-Y-Z Cartesian coordinate system is selected such that the X-Y
plane is parallel to tray 360. Tray 360 is preferably configured to
move vertically (along the Z direction), typically downward.
[0740] In various exemplary embodiments of the invention, apparatus
114 further comprises one or more leveling devices 132. Leveling
device 132 serves to straighten, level and/or establish a thickness
of the newly formed layer prior to the formation of the successive
layer thereon. Leveling device 132 can comprise one or more rollers
326. Rollers 326 can have a generally smooth surface or can have a
patterned surface. In some embodiments of the present invention one
or more of the layers is straightened while the formulation within
the layer is at a cured or partially cured or uncured state. In
these embodiments, leveling device 132 is capable of reforming the
solidified portion of the formulation. For example, when leveling
device 132 comprises one or more rollers at least one of these
rollers is capable of milling, grinding and/or flaking the
solidified portion of the formulation. Preferably, in these
embodiments, the roller has a non-smooth surface so as to
facilitate the milling, grinding and/or flaking. For example, the
surface of the roller can be patterned with blades and/or have a
shape of an auger.
[0741] In some embodiments of the present invention one or more of
the layers is straightened while the formulation within the layer
is uncured. In these embodiments, leveling device 132 can comprise
a roller or a blade, which is optionally and preferably, but not
necessarily, incapable of effecting milling, grinding and/or
flaking.
[0742] Leveling device 132 preferably comprises a waste collection
device 136 for collecting the excess material generated during
leveling. Waste collection device 136 may comprise any mechanism
that delivers the material to a waste tank or waste cartridge.
Optionally, leveling device 132 is a self-cleaning leveling device,
wherein cured or partially cured or uncured formulation is
periodically removed from leveling device 132. A representative
Example of a self-cleaning leveling device is illustrated in FIG.
7. Shown in FIG. 7 is a double roller having a first roller 356
that contacts and straightens a layer 358 and a second roller 354
that is in contact with the first roller 356 but not with the layer
358 and which is configured to remove the formulation from the
first roller 358. When first roller 356 has a non-smooth surface,
second roller 354 preferably is also non-smoothed wherein the
pattern formed on the surface of roller 354 is complementary to the
pattern formed on the surface of roller 356, so as to allow roller
354 to clean the surface of roller 358.
[0743] Apparatus 114 can also comprise a chamber 350 enclosing at
least heads 116 and tray 360, but may also enclose other components
of system 110, such as, but not limited to, devices 132 and 324,
frame 128 and the like. In some embodiments of the present
invention apparatus 114 comprises a chamber heater 352 that heats
the interior of chamber 350 as further detailed hereinabove.
Chamber 350 is preferably generally sealed to an environment
outside chamber 350.
[0744] In some embodiments of the present invention chamber 350
comprises a gas inlet 364 and the system comprises a gas source 366
configured for filling said chamber by an inert gas through gas
inlet 364. Gas source 366 can be a container filled with the inert
gas. The gas can be any of the inert gases described above.
Optionally, chamber 350 is also formed with a gas outlet 368 for
allowing the gas to exit chamber 350 if desired. Both inlet 366 and
outlet 368 are of the present embodiments provided with valves (not
shown) so as to controllably allow entry and/or exit of the gas to
and from chamber 350. Preferably, controller 152 generates,
continuously or intermittently, inflow and outflow of the inert gas
through gas inlet 366 and gas outlet 368. This can be achieved by
configuring controller 152 to control at least one of source 366,
inlet 364 and outlet 368. Optionally, system 110 comprises a gas
flow generating device 370, placed within chamber 350 and
configured for generating a flow of the inert gas within chamber
350. Device 370 can be a fan or a blower. Controller 152 can be
configured for controlling also device 370, for example, based on a
predetermined printing protocol.
[0745] In some embodiments of the present invention apparatus 114
comprises a mixing chamber 362 for preparing the modeling material
formulation prior to entry of the modeling material formulation
into a respective head. In the schematic illustration of FIG. 4,
which is not to be considered as limiting, chamber 362 receives
materials from different containers, mixes the received materials
and introduces the mix to two heads (heads 116b and 116a, in the
present example). However, this need not necessarily be the case
since in some embodiments chamber 362 can receive materials from
different containers, mixes the received materials and introduces
the mix only to more than two heads of only to one head.
Preferably, the position and fluid communication between mixing
chamber 362 and respective head is selected such that at least 80%
or at least 85% or at least 90% or at least 95% or at least 99% or
the modeling material formulation that enters the respective head
or heads (e.g., heads 116b and 116a in the present example) remains
uncured. For example, chamber 362 can be attached directly to the
printing head or the printing block, such that motion of the
printing head is accompanied by motion of the mixing chamber. These
embodiments are particularly useful when the formulation undergoes
fast polymerization reaction even in the absence of curing
radiation.
[0746] In use, the dispensing heads of unit 116 move in a scanning
direction, which is referred to herein as the X direction, and
selectively dispense building material in a predetermined
configuration in the course of their passage over tray 360. The
building material typically comprises one or more types of support
material and one or more types of modeling material. The passage of
the dispensing heads of unit 116 is followed by the curing of the
modeling material(s) by radiation source 126. In the reverse
passage of the heads, back to their starting point for the layer
just deposited, an additional dispensing of building material may
be carried out, according to predetermined configuration. In the
forward and/or reverse passages of the dispensing heads, the layer
thus formed may be straightened by leveling device 326, which
preferably follows the path of the dispensing heads in their
forward and/or reverse movement. Once the dispensing heads return
to their starting point along the X direction, they may move to
another position along an indexing direction, referred to herein as
the Y direction, and continue to build the same layer by reciprocal
movement along the X direction. Alternately, the dispensing heads
may move in the Y direction between forward and reverse movements
or after more than one forward-reverse movement. The series of
scans performed by the dispensing heads to complete a single layer
is referred to herein as a single scan cycle.
[0747] Once the layer is completed, tray 360 is lowered in the Z
direction to a predetermined Z level, according to the desired
thickness of the layer subsequently to be printed. The procedure is
repeated to form three-dimensional object 112 in a layerwise
manner.
[0748] In another embodiment, tray 360 may be displaced in the Z
direction between forward and reverse passages of the dispensing
head of unit 116, within the layer. Such Z displacement is carried
out in order to cause contact of the leveling device with the
surface in one direction and prevent contact in the other
direction.
[0749] System 110 optionally and preferably comprises a building
material supply system 330 which comprises the building material
containers or cartridges and supplies a plurality of building
materials to fabrication apparatus 114.
[0750] A control unit 340 controls fabrication apparatus 114 and
optionally and preferably also supply system 330. Control unit 340
typically includes an electronic circuit configured to perform the
controlling operations. Control unit 340 preferably communicates
with a data processor 154 which transmits digital data pertaining
to fabrication instructions based on computer object data, e.g., a
CAD configuration represented on a computer readable medium in a
form of, for example, a Standard Tessellation Language (STL) format
Standard Tessellation Language (STL), StereoLithography Contour
(SLC) format, Virtual Reality Modeling Language (VRML), Additive
Manufacturing File (AMF) format, Drawing Exchange Format (DXF),
Polygon File Format (PLY) or any other format suitable for CAD.
Typically, control unit 340 controls the voltage applied to each
printing head or nozzle array and the temperature of the building
material in the respective printing head.
[0751] Once the manufacturing data is loaded to control unit 340 it
can operate without user intervention. In some embodiments, control
unit 340 receives additional input from the operator, e.g., using
data processor 154 or using a user interface 118 communicating with
unit 340. User interface 118 can be of any type known in the art,
such as, but not limited to, a keyboard, a touch screen and the
like. For example, control unit 340 can receive, as additional
input, one or more building material types and/or attributes, such
as, but not limited to, color, characteristic distortion and/or
transition temperature, viscosity, electrical property, magnetic
property. Other attributes and groups of attributes are also
contemplated.
[0752] In some embodiments of the present invention hardening
device(s) 324 are also controlled by controller 152. For example,
controller 152 can activate and deactivate hardening device(s) 324
according to a predetermined printing protocol. When system 110
comprises two different radiation sources that apply different
types of curing energies, controller 152 preferably controls each
of these radiation sources separately. For example, controller 152
can signal a first radiation source to deliver a first type of
curing energy (e.g., in the form of UV radiation), and a second
radiation source to deliver a second type of curing energy (e.g.,
thermal energy), such that the two types of curing energies are
delivered according to a predetermined curing scenario
sequentially, simultaneously or intermittently. In any of these
curing scenarios, controller 152 can also signal the radiation
source(s) to deliver the energy repeatedly.
[0753] System 110 can fabricate an object by depositing different
materials from different printing heads. In various exemplary
embodiments of the invention the electronic circuit of controller
152 is configured to form voxel blocks, wherein, for each block, a
ratio between a number of voxels of the first composition in the
block and a number of voxels of the second composition in the block
corresponds to the selected ratio received from data processor 154
or user interface 118.
[0754] The system of present embodiments provides the ability to
select materials from a given number of materials and define
desired combinations of the selected materials and their
properties. The spatial locations of the deposition of each
material with the layer are defined, either to effect occupation of
different three-dimensional spatial locations by different
materials, or to effect occupation of substantially the same
three-dimensional location or adjacent three-dimensional locations
by two or more different materials so as to allow post-deposition
spatial combination of the materials within the layer.
[0755] It is expected that during the life of a patent maturing
from this application many relevant components of a ROMP system as
described herein will be developed and the scope of the terms ROMP
monomer, ROMP catalyst, ROMP activator, ROMP pre-catalyst, is
intended to include all such new technologies a priori.
[0756] It is expected that during the life of a patent maturing
from this application many relevant degradable capsules and other
technologies for physically separating components in a modeling
material formulation as described herein will be developed and the
scope of the terms physical separation and degradable capsule, is
intended to include all such new technologies a priori.
[0757] As used herein the term "about" refers to .+-.10%.
[0758] The terms "comprises", "comprising", "includes",
"including", "having" and their conjugates mean "including but not
limited to".
[0759] The term "consisting of" means "including and limited
to".
[0760] The term "consisting essentially of" means that the
composition, method or structure may include additional
ingredients, steps and/or parts, but only if the additional
ingredients, steps and/or parts do not materially alter the basic
and novel characteristics of the claimed composition, method or
structure.
[0761] As used herein, the singular form "a", "an" and "the"
include plural references unless the context clearly dictates
otherwise. For example, the term "a compound" or "at least one
compound" may include a plurality of compounds, including mixtures
thereof.
[0762] Throughout this application, various embodiments of this
invention may be presented in a range format. It should be
understood that the description in range format is merely for
convenience and brevity and should not be construed as an
inflexible limitation on the scope of the invention. Accordingly,
the description of a range should be considered to have
specifically disclosed all the possible subranges as well as
individual numerical values within that range. For example,
description of a range such as from 1 to 6 should be considered to
have specifically disclosed subranges such as from 1 to 3, from 1
to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as
well as individual numbers within that range, for example, 1, 2, 3,
4, 5, and 6. This applies regardless of the breadth of the
range.
[0763] Whenever a numerical range is indicated herein, it is meant
to include any cited numeral (fractional or integral) within the
indicated range. The phrases "ranging/ranges between" a first
indicate number and a second indicate number and "ranging/ranges
from" a first indicate number "to" a second indicate number are
used herein interchangeably and are meant to include the first and
second indicated numbers and all the fractional and integral
numerals therebetween.
[0764] As used herein the term "method" refers to manners, means,
techniques and procedures for accomplishing a given task including,
but not limited to, those manners, means, techniques and procedures
either known to, or readily developed from known manners, means,
techniques and procedures by practitioners of the chemical,
pharmacological, biological, biochemical and medical arts.
[0765] Herein throughout, the phrase "linking moiety" or "linking
group" describes a group that connects two or more moieties or
groups in a compound. A linking moiety is typically derived from a
bi- or tri-functional compound, and can be regarded as a bi- or
tri-radical moiety, which is connected to two or three other
moieties, via two or three atoms thereof, respectively.
[0766] Exemplary linking moieties include a hydrocarbon moiety or
chain, optionally interrupted by one or more heteroatoms, as
defined herein, and/or any of the chemical groups listed below,
when defined as linking groups.
[0767] When a chemical group is referred to herein as "end group"
it is to be interpreted as a substituent, which is connected to
another group via one atom thereof.
[0768] Herein throughout, the term "hydrocarbon" collectively
describes a chemical group composed mainly of carbon and hydrogen
atoms. A hydrocarbon can be comprised of alkyl, alkene, alkyne,
aryl, and/or cycloalkyl, each can be substituted or unsubstituted,
and can be interrupted by one or more heteroatoms. The number of
carbon atoms can range from 2 to 20, and is preferably lower, e.g.,
from 1 to 10, or from 1 to 6, or from 1 to 4. A hydrocarbon can be
a linking group or an end group.
[0769] Bisphenol A is An example of a hydrocarbon comprised of 2
aryl groups and one alkyl group.
[0770] As used herein, the term "amine" describes both a --NR'R''
group and a --NR'-- group, wherein R' and R'' are each
independently hydrogen, alkyl, cycloalkyl, aryl, as these terms are
defined hereinbelow.
[0771] The amine group can therefore be a primary amine, where both
R' and R'' are hydrogen, a secondary amine, where R' is hydrogen
and R'' is alkyl, cycloalkyl or aryl, or a tertiary amine, where
each of R' and R'' is independently alkyl, cycloalkyl or aryl.
[0772] Alternatively, R' and R'' can each independently be
hydroxyalkyl, trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl,
heteroaryl, heteroalicyclic, amine, halide, sulfonate, sulfoxide,
phosphonate, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy,
thioaryloxy, cyano, nitro, azo, sulfonamide, carbonyl,
C-carboxylate, O-carboxylate, N-thiocarbamate, O-thiocarbamate,
urea, thiourea, N-carbamate, O-carbamate, C-amide, N-amide, guanyl,
guanidine and hydrazine.
[0773] The term "amine" is used herein to describe a --NR'R'' group
in cases where the amine is an end group, as defined hereinunder,
and is used herein to describe a --NR'-- group in cases where the
amine is a linking group or is or part of a linking moiety.
[0774] The term "alkyl" describes a saturated aliphatic hydrocarbon
including straight chain and branched chain groups. Preferably, the
alkyl group has 1 to 20 carbon atoms. Whenever a numerical range;
e.g., "1-20", is stated herein, it implies that the group, in this
case the alkyl group, may contain 1 carbon atom, 2 carbon atoms, 3
carbon atoms, etc., up to and including 20 carbon atoms. More
preferably, the alkyl is a medium size alkyl having 1 to 10 carbon
atoms. Most preferably, unless otherwise indicated, the alkyl is a
lower alkyl having 1 to 4 carbon atoms (C(1-4) alkyl). The alkyl
group may be substituted or unsubstituted. Substituted alkyl may
have one or more substituents, whereby each substituent group can
independently be, for example, hydroxyalkyl, trihaloalkyl,
cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic,
amine, halide, sulfonate, sulfoxide, phosphonate, hydroxy, alkoxy,
aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, nitro, azo,
sulfonamide, C-carboxylate, O-carboxylate, N-thiocarbamate,
O-thiocarbamate, urea, thiourea, N-carbamate, O-carbamate, C-amide,
N-amide, guanyl, guanidine and hydrazine.
[0775] The alkyl group can be an end group, as this phrase is
defined hereinabove, wherein it is attached to a single adjacent
atom, or a linking group, as this phrase is defined hereinabove,
which connects two or more moieties via at least two carbons in its
chain. When the alkyl is a linking group, it is also referred to
herein as "alkylene" or "alkylene chain".
[0776] Alkene (or alkenyl) and Alkyne (or alkynyl), as used herein,
are an alkyl, as defined herein, which contains one or more double
bond or triple bond, respectively.
[0777] The term "cycloalkyl" describes an all-carbon monocyclic
ring or fused rings (i.e., rings which share an adjacent pair of
carbon atoms) group where one or more of the rings does not have a
completely conjugated pi-electron system. Examples include, without
limitation, cyclohexane, adamantine, norbornyl, isobornyl, and the
like. The cycloalkyl group may be substituted or unsubstituted.
Substituted cycloalkyl may have one or more substituents, whereby
each substituent group can independently be, for example,
hydroxyalkyl, trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl,
heteroaryl, heteroalicyclic, amine, halide, sulfonate, sulfoxide,
phosphonate, hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy,
thioaryloxy, cyano, nitro, azo, sulfonamide, C-carboxylate,
O-carboxylate, N-thiocarbamate, O-thiocarbamate, urea, thiourea,
N-carbamate, O-carbamate, C-amide, N-amide, guanyl, guanidine and
hydrazine. The cycloalkyl group can be an end group, as this phrase
is defined hereinabove, wherein it is attached to a single adjacent
atom, or a linking group, as this phrase is defined hereinabove,
connecting two or more moieties at two or more positions
thereof.
[0778] The term "heteroalicyclic" describes a monocyclic or fused
ring group having in the ring(s) one or more atoms such as
nitrogen, oxygen and sulfur. The rings may also have one or more
double bonds. However, the rings do not have a completely
conjugated pi-electron system. Representative examples are
piperidine, piperazine, tetrahydrofuran, tetrahydropyrane,
morpholine, oxalidine, and the like. The heteroalicyclic may be
substituted or unsubstituted. Substituted heteroalicyclic may have
one or more substituents, whereby each substituent group can
independently be, for example, hydroxyalkyl, trihaloalkyl,
cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic,
amine, halide, sulfonate, sulfoxide, phosphonate, hydroxy, alkoxy,
aryloxy, thiohydroxy, thioalkoxy, thioaryloxy, cyano, nitro, azo,
sulfonamide, C-carboxylate, O-carboxylate, N-thiocarbamate,
O-thiocarbamate, urea, thiourea, O-carbamate, N-carbamate, C-amide,
N-amide, guanyl, guanidine and hydrazine. The heteroalicyclic group
can be an end group, as this phrase is defined hereinabove, where
it is attached to a single adjacent atom, or a linking group, as
this phrase is defined hereinabove, connecting two or more moieties
at two or more positions thereof.
[0779] The term "aryl" describes an all-carbon monocyclic or
fused-ring polycyclic (i.e., rings which share adjacent pairs of
carbon atoms) groups having a completely conjugated pi-electron
system. The aryl group may be substituted or unsubstituted.
Substituted aryl may have one or more substituents, whereby each
substituent group can independently be, for example, hydroxyalkyl,
trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl,
heteroalicyclic, amine, halide, sulfonate, sulfoxide, phosphonate,
hydroxy, alkoxy, aryloxy, thiohydroxy, thioalkoxy, thioaryloxy,
cyano, nitro, azo, sulfonamide, C-carboxylate, O-carboxylate,
N-thiocarbamate, O-thiocarbamate, urea, thiourea, N-carbamate,
O-carbamate, C-amide, N-amide, guanyl, guanidine and hydrazine. The
aryl group can be an end group, as this term is defined
hereinabove, wherein it is attached to a single adjacent atom, or a
linking group, as this term is defined hereinabove, connecting two
or more moieties at two or more positions thereof.
[0780] The term "heteroaryl" describes a monocyclic or fused ring
(i.e., rings which share an adjacent pair of atoms) group having in
the ring(s) one or more atoms, such as, for example, nitrogen,
oxygen and sulfur and, in addition, having a completely conjugated
pi-electron system. Examples, without limitation, of heteroaryl
groups include pyrrole, furan, thiophene, imidazole, oxazole,
thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline
and purine. The heteroaryl group may be substituted or
unsubstituted. Substituted heteroaryl may have one or more
substituents, whereby each substituent group can independently be,
for example, hydroxyalkyl, trihaloalkyl, cycloalkyl, alkenyl,
alkynyl, aryl, heteroaryl, heteroalicyclic, amine, halide,
sulfonate, sulfoxide, phosphonate, hydroxy, alkoxy, aryloxy,
thiohydroxy, thioalkoxy, thioaryloxy, cyano, nitro, azo,
sulfonamide, C-carboxylate, O-carboxylate, N-thiocarbamate,
O-thiocarbamate, urea, thiourea, O-carbamate, N-carbamate, C-amide,
N-amide, guanyl, guanidine and hydrazine. The heteroaryl group can
be an end group, as this phrase is defined hereinabove, where it is
attached to a single adjacent atom, or a linking group, as this
phrase is defined hereinabove, connecting two or more moieties at
two or more positions thereof. Representative examples are
pyridine, pyrrole, oxazole, indole, purine and the like.
[0781] The term "halide", "halogen" and "halo" describe fluorine,
chlorine, bromine or iodine.
[0782] The term "haloalkyl" describes an alkyl group as defined
above, further substituted by one or more halide.
[0783] The term "sulfate" describes a --O--S(.dbd.O).sub.2--OR' end
group, as this term is defined hereinabove, or an
--O--S(.dbd.O).sub.2--O-- linking group, as these phrases are
defined hereinabove, where R' is as defined hereinabove.
[0784] The term "thiosulfate" describes a
--O--S(.dbd.S)(.dbd.O)--OR' end group or a
--O--S(.dbd.S)(.dbd.O)--O-- linking group, as these phrases are
defined hereinabove, where R' is as defined hereinabove.
[0785] The term "sulfite" describes an --O--S(.dbd.O)--O--R' end
group or a --O--S(.dbd.O)--O-- group linking group, as these
phrases are defined hereinabove, where R' is as defined
hereinabove.
[0786] The term "thiosulfite" describes a --O--S(.dbd.S)--O--R' end
group or an --O--S(.dbd.S)--O-- group linking group, as these
phrases are defined hereinabove, where R' is as defined
hereinabove.
[0787] The term "sulfinate" describes a --S(.dbd.O)--OR' end group
or an --S(.dbd.O)--O-- group linking group, as these phrases are
defined hereinabove, where R' is as defined hereinabove.
[0788] The term "sulfoxide" or "sulfinyl" describes a --S(.dbd.O)R'
end group or an --S(.dbd.O)-- linking group, as these phrases are
defined hereinabove, where R' is as defined hereinabove.
[0789] The term "sulfonate" describes a --S(.dbd.O).sub.2--R' end
group or an --S(.dbd.O).sub.2-- linking group, as these phrases are
defined hereinabove, where R' is as defined herein.
[0790] The term "S-sulfonamide" describes a
--S(.dbd.O).sub.2--NR'R'' end group or a --S(.dbd.O).sub.2--NR'--
linking group, as these phrases are defined hereinabove, with R'
and R'' as defined herein.
[0791] The term "N-sulfonamide" describes an
R'S(.dbd.O).sub.2--NR''-- end group or a --S(.dbd.O).sub.2--NR'--
linking group, as these phrases are defined hereinabove, where R'
and R'' are as defined herein.
[0792] The term "disulfide" refers to a --S--SR' end group or a
--S--S-- linking group, as these phrases are defined hereinabove,
where R' is as defined herein.
[0793] The term "oxo" as used herein, describes a (.dbd.O) group,
wherein an oxygen atom is linked by a double bond to the atom
(e.g., carbon atom) at the indicated position.
[0794] The term "thiooxo" as used herein, describes a (.dbd.S)
group, wherein a sulfur atom is linked by a double bond to the atom
(e.g., carbon atom) at the indicated position.
[0795] The term "oxime" describes a .dbd.N--OH end group or a
.dbd.N--O-- linking group, as these phrases are defined
hereinabove.
[0796] The term "hydroxyl" describes a --OH group.
[0797] The term "alkoxy" describes both an --O-alkyl and an
--O-cycloalkyl group, as defined herein.
[0798] The term "aryloxy" describes both an --O-aryl and an
--O-heteroaryl group, as defined herein.
[0799] The term "thiohydroxy" describes a --SH group.
[0800] The term "thioalkoxy" describes both a --S-alkyl group, and
a --S-cycloalkyl group, as defined herein.
[0801] The term "thioaryloxy" describes both a --S-aryl and a
--S-heteroaryl group, as defined herein.
[0802] The "hydroxyalkyl" is also referred to herein as "alcohol",
and describes an alkyl, as defined herein, substituted by a hydroxy
group.
[0803] The term "cyano" describes a --C.ident.N group.
[0804] The term "cyanurate" describes a
##STR00042##
end group or
##STR00043##
linking group, with R' and R'' as defined herein.
[0805] The term "isocyanurate" describes a
##STR00044##
end group or a
##STR00045##
linking group, with R' and R'' as defined herein.
[0806] The term "thiocyanurate" describes a
##STR00046##
end group or
##STR00047##
linking group, with R' and R'' as defined herein.
[0807] The term "isocyanate" describes an --N.dbd.C.dbd.O
group.
[0808] The term "isothiocyanate" describes an --N.dbd.C.dbd.S
group.
[0809] The term "nitro" describes an --NO.sub.2 group.
[0810] The term "acyl halide" describes a --(C.dbd.O)R'''' group
wherein R'''' is halide, as defined hereinabove.
[0811] The term "azo" or "diazo" describes an --N.dbd.NR' end group
or an --N.dbd.N-- linking group, as these phrases are defined
hereinabove, with R' as defined hereinabove.
[0812] The term "peroxo" describes an --O--OR' end group or an
--O--O-- linking group, as these phrases are defined hereinabove,
with R' as defined hereinabove.
[0813] The term "carboxylate" as used herein encompasses
C-carboxylate and O-carboxylate.
[0814] The term "C-carboxylate" describes a --C(.dbd.O)--OR' end
group or a --C(.dbd.O)--O-- linking group, as these phrases are
defined hereinabove, where R' is as defined herein.
[0815] The term "O-carboxylate" describes a --OC(.dbd.O)R' end
group or a --OC(.dbd.O)-- linking group, as these phrases are
defined hereinabove, where R' is as defined herein.
[0816] A carboxylate can be linear or cyclic. When cyclic, R' and
the carbon atom are linked together to form a ring, in
C-carboxylate, and this group is also referred to as lactone.
Alternatively, R' and O are linked together to form a ring in
O-carboxylate. Cyclic carboxylates can function as a linking group,
for example, when an atom in the formed ring is linked to another
group.
[0817] The term "thiocarboxylate" as used herein encompasses
C-thiocarboxylate and 0-thiocarboxylate.
[0818] The term "C-thiocarboxylate" describes a --C(.dbd.S)--OR'
end group or a --C(.dbd.S)--O-- linking group, as these phrases are
defined hereinabove, where R' is as defined herein.
[0819] The term "O-thiocarboxylate" describes a --OC(.dbd.S)R' end
group or a --OC(.dbd.S)-- linking group, as these phrases are
defined hereinabove, where R' is as defined herein.
[0820] A thiocarboxylate can be linear or cyclic. When cyclic, R'
and the carbon atom are linked together to form a ring, in
C-thiocarboxylate, and this group is also referred to as
thiolactone. Alternatively, R' and O are linked together to form a
ring in O-thiocarboxylate. Cyclic thiocarboxylates can function as
a linking group, for example, when an atom in the formed ring is
linked to another group.
[0821] The term "carbamate" as used herein encompasses N-carbamate
and O-carbamate.
[0822] The term "N-carbamate" describes an R''OC(.dbd.O)--NR'-- end
group or a --OC(.dbd.O)--NR'-- linking group, as these phrases are
defined hereinabove, with R' and R'' as defined herein.
[0823] The term "O-carbamate" describes an --OC(.dbd.O)--NR'R'' end
group or an --OC(.dbd.O)--NR'-- linking group, as these phrases are
defined hereinabove, with R' and R'' as defined herein.
[0824] A carbamate can be linear or cyclic. When cyclic, R' and the
carbon atom are linked together to form a ring, in O-carbamate.
Alternatively, R' and O are linked together to form a ring in
N-carbamate. Cyclic carbamates can function as a linking group, for
example, when an atom in the formed ring is linked to another
group.
[0825] The term "carbamate" as used herein encompasses N-carbamate
and O-carbamate.
[0826] The term "thiocarbamate" as used herein encompasses
N-thiocarbamate and O-thiocarbamate.
[0827] The term "O-thiocarbamate" describes a --OC(.dbd.S)--NR'R''
end group or a --OC(.dbd.S)--NR'-- linking group, as these phrases
are defined hereinabove, with R' and R'' as defined herein.
[0828] The term "N-thiocarbamate" describes an R''OC(.dbd.S)NR'--
end group or a --OC(.dbd.S)NR'-- linking group, as these phrases
are defined hereinabove, with R' and R'' as defined herein.
[0829] Thiocarbamates can be linear or cyclic, as described herein
for carbamates.
[0830] The term "dithiocarbamate" as used herein encompasses
S-dithiocarbamate and N-dithiocarbamate.
[0831] The term "S-dithiocarbamate" describes a
--SC(.dbd.S)--NR'R'' end group or a --SC(.dbd.S)NR'-- linking
group, as these phrases are defined hereinabove, with R' and R'' as
defined herein.
[0832] The term "N-dithiocarbamate" describes an R''SC(.dbd.S)NR'--
end group or a --SC(.dbd.S)NR'-- linking group, as these phrases
are defined hereinabove, with R' and R'' as defined herein.
[0833] The term "urea", which is also referred to herein as
"ureido", describes a --NR'C(.dbd.O)--NR''R''' end group or a
--NR'C(.dbd.O)--NR''-- linking group, as these phrases are defined
hereinabove, where R' and R'' are as defined herein and R''' is as
defined herein for R' and R''.
[0834] The term "thiourea", which is also referred to herein as
"thioureido", describes a --NR'--C(.dbd.S)--NR''R''' end group or a
--NR'--C(.dbd.S)--NR''-- linking group, with R', R'' and R''' as
defined herein.
[0835] The term "amide" as used herein encompasses C-amide and
N-amide.
[0836] The term "C-amide" describes a --C(.dbd.O)--NR'R'' end group
or a --C(.dbd.O)--NR'-- linking group, as these phrases are defined
hereinabove, where R' and R'' are as defined herein.
[0837] The term "N-amide" describes a R'C(.dbd.O)--NR''-- end group
or a R'C(.dbd.O)--N-- linking group, as these phrases are defined
hereinabove, where R' and R'' are as defined herein.
[0838] An amide can be linear or cyclic. When cyclic, R' and the
carbon atom are linked together to form a ring, in C-amide, and
this group is also referred to as lactam. Cyclic amides can
function as a linking group, for example, when an atom in the
formed ring is linked to another group.
[0839] The term "guanyl" describes a R'R''NC(.dbd.N)-- end group or
a --R'NC(.dbd.N)-- linking group, as these phrases are defined
hereinabove, where R' and R'' are as defined herein.
[0840] The term "guanidine" describes a --R'NC(.dbd.N)--NR''R'''
end group or a --R'NC(.dbd.N)--NR''-- linking group, as these
phrases are defined hereinabove, where R', R'' and R''' are as
defined herein.
[0841] The term "hydrazine" describes a --NR'--NR''R''' end group
or a --NR'--NR''-- linking group, as these phrases are defined
hereinabove, with R', R'', and R''' as defined herein.
[0842] As used herein, the term "hydrazide" describes a
--C(.dbd.O)--NR'--NR''R''' end group or a --C(.dbd.O)--NR'--NR''--
linking group, as these phrases are defined hereinabove, where R',
R'' and R''' are as defined herein.
[0843] As used herein, the term "thiohydrazide" describes a
--C(.dbd.S)--NR'--NR''R''' end group or a --C(.dbd.S)--NR'--NR''--
linking group, as these phrases are defined hereinabove, where R',
R'' and R''' are as defined herein.
[0844] As used herein, the term "alkylene glycol" describes a
--O--[(CR'R'').sub.z--O].sub.y--R''' end group or a
--O--[(CR'R'').sub.z--O].sub.y-- linking group, with R', R'' and
R''' being as defined herein, and with z being an integer of from 1
to 10, preferably, 2-6, more preferably 2 or 3, and y being an
integer of 1 or more. Preferably R' and R'' are both hydrogen. When
z is 2 and y is 1, this group is ethylene glycol. When z is 3 and y
is 1, this group is propylene glycol.
[0845] When y is greater than 4, the alkylene glycol is referred to
herein as poly(alkylene glycol). In some embodiments of the present
invention, a poly(alkylene glycol) group or moiety can have from 10
to 200 repeating alkylene glycol units, such that z is 10 to 200,
preferably 10-100, more preferably 10-50.
[0846] The term "silyl" describes a --SiR'R''R''' end group or a
--SiR'R''-- linking group, as these phrases are defined
hereinabove, whereby each of R', R'' and R''' are as defined
herein.
[0847] The term "siloxy" describes a --Si(OR')R''R''' end group or
a --Si(OR')R''-- linking group, as these phrases are defined
hereinabove, whereby each of R', R'' and R''' are as defined
herein.
[0848] The term "silaza" describes a --Si(NR'R'')R''' end group or
a --Si(NR'R'')-- linking group, as these phrases are defined
hereinabove, whereby each of R', R'' and R''' is as defined
herein.
[0849] The term "silicate" describes a --O--Si(OR')(OR'')(OR''')
end group or a --O--Si(OR')(OR'')-- linking group, as these phrases
are defined hereinabove, with R', R'' and R''' as defined
herein.
[0850] The term "boryl" describes a --BR'R'' end group or a --BR'--
linking group, as these phrases are defined hereinabove, with R'
and R'' are as defined herein.
[0851] The term "borate" describes a --O--B(OR')(OR'') end group or
a --O--B(OR')(O--) linking group, as these phrases are defined
hereinabove, with R' and R'' are as defined herein.
[0852] As used herein, the term "epoxide" describes a
##STR00048##
end group or a
##STR00049##
linking group, as these phrases are defined hereinabove, where R',
R'' and R''' are as defined herein.
[0853] As used herein, the term "methyleneamine" describes an
--NR'--CH.sub.2--CH.dbd.CR''R''' end group or a
--NR'--CH.sub.2--CH.dbd.CR''-- linking group, as these phrases are
defined hereinabove, where R', R'' and R''' are as defined
herein.
[0854] The term "phosphonate" describes a --P(.dbd.O)(OR')(OR'')
end group or a --P(.dbd.O)(OR')(O)-- linking group, as these
phrases are defined hereinabove, with R' and R'' as defined
herein.
[0855] The term "thiophosphonate" describes a
--P(.dbd.S)(OR')(OR'') end group or a --P(.dbd.S)(OR')(O)-- linking
group, as these phrases are defined hereinabove, with R' and R'' as
defined herein.
[0856] The term "phosphinyl" describes a --PR'R'' end group or a
--PR'-- linking group, as these phrases are defined hereinabove,
with R' and R'' as defined hereinabove.
[0857] The term "phosphine oxide" describes a --P(.dbd.O)(R')(R'')
end group or a --P(.dbd.O)(R')-- linking group, as these phrases
are defined hereinabove, with R' and R'' as defined herein.
[0858] The term "phosphine sulfide" describes a
--P(.dbd.S)(R')(R'') end group or a --P(.dbd.S)(R')-- linking
group, as these phrases are defined hereinabove, with R' and R'' as
defined herein.
[0859] The term "phosphite" describes an --O--PR'(.dbd.O)(OR'') end
group or an --O--PH(.dbd.O)(O)-- linking group, as these phrases
are defined hereinabove, with R' and R'' as defined herein.
[0860] The term "carbonyl" or "carbonate" as used herein, describes
a --C(.dbd.O)--R' end group or a --C(.dbd.O)-- linking group, as
these phrases are defined hereinabove, with R' as defined herein.
This term encompasses ketones and aldehydes.
[0861] The term "thiocarbonyl" as used herein, describes a
--C(.dbd.S)--R' end group or a --C(.dbd.S)-- linking group, as
these phrases are defined hereinabove, with R' as defined
herein.
[0862] The term "oxime" describes a .dbd.N--OH end group or a
.dbd.N--O-- linking group, as these phrases are defined
hereinabove.
[0863] The term "cyclic ring" encompasses a cycloalkyl, a
heretroalicyclic, an aryl (an aromatic ring) and a heteroaryl (a
heteroaromatic ring).
[0864] Other chemical groups are to be regarded according to the
common definition thereof in the art and/or in line of the
definitions provided herein.
[0865] It is appreciated that certain features of the invention,
which are, for clarity, described in the context of separate
embodiments, may also be provided in combination in a single
embodiment. Conversely, various features of the invention, which
are, for brevity, described in the context of a single embodiment,
may also be provided separately or in any suitable subcombination
or as suitable in any other described embodiment of the invention.
Certain features described in the context of various embodiments
are not to be considered essential features of those embodiments,
unless the embodiment is inoperative without those elements.
[0866] Various embodiments and aspects of the present invention as
delineated hereinabove and as claimed in the claims section below
find experimental support in the following examples.
Examples
[0867] Reference is now made to the following examples, which
together with the above descriptions illustrate some embodiments of
the invention in a non limiting fashion.
Materials and Experimental Methods
[0868] Materials:
[0869] A mono-functional DCPD monomer useful in RIM was used as a
first ROMP monomer (a first material).
[0870] A tri-functional ROMP monomer such as TCPD was used as a
second ROMP monomer.
[0871] A ROMP pre-catalyst, activatable by a Lewis acid was used as
a catalyst component.
[0872] PhSiCl.sub.3 was used as a Lewis acid activator.
[0873] P(OEt).sub.3 was used as a Lewis base ROMP inhibitor.
[0874] Trilene CP1100 (an ethylene-propylene liquid copolymer) was
used as an exemplary elastomer. Alternatively, EPR and/or EPDM can
be used instead.
[0875] Model formulation A was prepared by mixing the first and
second ROMP monomers, the catalyst and the inhibitor.
[0876] Model formulation B was prepared by mixing the first ROMP
monomer, an activator and an elastomer.
[0877] Both the elastomer and the trifunctional ROMP monomer can
act as a second material according to the present embodiments, and
digitally controlling the ratio of the jetted formulations allows
controlling the object's properties, at the voxel level, as defined
herein.
[0878] Methods:
[0879] Model formulation A is jetted by inkjet head A or a set of
inkjet heads A and Model formulation B is jetted by inkjet head B
or a set of inkjet head B.
[0880] The inkjet temperature is between 40-70.degree. C., as
described herein.
[0881] The model formulation are jetted on a heated tray,
simultaneously, and are subsequently exposed to heat, as described
herein, so as to effect ROMP.
[0882] Following printing process, obtained material is subjected
to thermal post-process without causing destructive oxidation of
the PDCPD.
[0883] The ratio between the jetted formulations is digitally
predetermined, controlling the amount (weight) jetted from every
head. Optionally, drop sizes are controlled to achieve a selected
weight between model formulations A and B, while considering
viscosity and/or density of the formulations.
[0884] In mold experiments, model formulations A and B are mixed
together in a pre-mixing chamber and the obtained mixture is
transferred to a mold. The mold is heated at about 80.degree. C. to
give a cured material within a few minutes.
[0885] The elasticity of the obtained cured material was determined
by measuring the % of strain recovery, at 100.degree. C., by DMA
measurements performed using DMA Q800 measurement device (TA
Instruments (Belgium)). The strain recovery is indicative of an
elastic response, i.e. plastic deformation. When % of strain
recovery is high, the material is more elastic and tends to be less
deformed at the tested temperature.
[0886] DMA measurements indicate the temperature at which storage
modulus decreases by 50%. This value is indicative of the stiffness
degree of the material. Decrease of storage modulus at a high
temperature indicates a stiff material and at a low temperature it
indicates weak material.
[0887] Izod Impact was measured by RESIL 5.5J (CEAST, Italy).
Results
[0888] Tables 3 and 4 below present the mechanical properties of
the cured material obtained upon mixing model formulations A and B
at a weight ratio of 1:1 (50:50 weight percents) (Table 3), and at
a weight ratio of 3:7 (30:70 weight percents) (Table 4).
[0889] These data is indicative of the controllability of the
object's properties when such formulations are used in a 3D inkjet
printing method according to the present embodiments.
[0890] The obtained data indicate that by controlling the A:B
ratio, Impact resistance and elasticity can be finely
controlled.
TABLE-US-00005 TABLE 3 Jet A Jet B DMA ROMP TCPD Telene RIM Trilene
Strain Izod, (Tg, Tan monomer trimer catalyst 4 P(OEt).sub.3
monomer CP1100 PhSiCl.sub.3 recovery notched delta) 80% 20% 0.049%
30 ppm 91.92% 8% 0.08% 95% 170 .+-. 16 195
TABLE-US-00006 TABLE 4 Jet A Jet B DMA RIM TCPD Telene RIM Trilene
Strain Izod, (Tg, Tan monomer trimer catalyst 4 P(OEt).sub.3
monomer CP1100 PhSiCl.sub.3 recovery notched delta) 80% 20% 0.049%
30 ppm 91.92% 8% 0.08% 80.25% 250 .+-. 27 191
[0891] Similar results are obtained while using Trilene 77 instead
of CP1100.
[0892] Additional experiments were performed for assessing the
effect of various elastomeric materials on the mechanical
properties (Impact resistance, HDT) of cured ROMP materials. All
tested formulations include a mixture of DCPD and a CPD trimer as a
ROMP monomer, and a ROMP catalyst.
[0893] Tested elastomeric materials were all hydrophobic, and were
selected as such for assuring sufficient dissolvability or
dispersibility in the formulation.
[0894] Table 5 below presents the mechanical properties of the
obtained cured materials.
TABLE-US-00007 TABLE 5 Elastomer Chemical Concentration Impact HDT
Trade name structure Mw (% wt.) (J/m) (.degree. C.) No elastomer --
-- 0 78 142 Indopol Polybutene 10 kDa 6 382 144 H-18000 Indopol
Polybutene 7 kDa 8 330 144 H-6000 Kuraray L- Polybutadiene 8 kDa 8
69 151 BR-307 Trilene CP EPR 6.6 kDa 8 130 142 1100* Trilene CP EPR
6.6 kDa 6 100 146 1100* Trilene CP EPR 6.6 kDa 4 212 142 1100*
Trilene EPR 23 kDa 5 302 151 CP80** Trilene EPDM 39 kDa 3.6 209 140
67** Trilene EPDM 27 kDa 5 450 128 77** *Jettability of the
formulation in a 3D inkjet printing system was good **Jettability
of the formulation in a 3D inkjet printing system was not
continuous
[0895] The data presented in Table 5 suggests the following:
[0896] While high molecular weight elastomers such as an EPDM
elastomer provide exceptional mechanical properties, such
elastomers are less suitable for 3D inkjet printing applications
due to jetting instability. Low molecular weight elastomers with
unsaturated backbone, on the other hand, provide substantially
inferior mechanical properties, with the Impact resistance being
lower than the control (without elastomer). Without being bound by
any particular theory, it is assumed that such low molecular weight
elastomers participate in the olefin metathesis, and hence their
effect on the mechanical properties is less pronounced.
[0897] Low molecular weight elastomers which include saturated
backbone, and hence are not expected to participate in olefin
metathesis, provide for improved Impact resistance compared to the
control, and are typically further characterized by good
jettability, and hence may be suitable for 3D inkjet printing.
[0898] Without being bound by any particular theory, it is
suggested that in order to obtain a toughening and/or impact
modifying effect, phase separation should be effected in the cured
material.
[0899] It is therefore suggested that a suitable elastomeric
material should be sufficiently hydrophobic so as to be dissolvable
or dispersible in the uncured formulation, yet should not form a
part of the polymeric matrix forming the cured modeling material,
that is, should be capable of forming a multiphasic (e.g.,
biphasic) structure when blended with the cured material, as
discussed herein.
[0900] Although the invention has been described in conjunction
with specific embodiments thereof, it is evident that many
alternatives, modifications and variations will be apparent to
those skilled in the art. Accordingly, it is intended to embrace
all such alternatives, modifications and variations that fall
within the spirit and broad scope of the appended claims.
[0901] All publications, patents and patent applications mentioned
in this specification are herein incorporated in their entirety by
reference into the specification, to the same extent as if each
individual publication, patent or patent application was
specifically and individually indicated to be incorporated herein
by reference. In addition, citation or identification of any
reference in this application shall not be construed as an
admission that such reference is available as prior art to the
present invention. To the extent that section headings are used,
they should not be construed as necessarily limiting.
* * * * *