U.S. patent application number 15/468816 was filed with the patent office on 2017-07-13 for method of making foam.
The applicant listed for this patent is Sealed Air Corporation (US). Invention is credited to William J. Mahon, Henry J. Ruddy.
Application Number | 20170198112 15/468816 |
Document ID | / |
Family ID | 49619830 |
Filed Date | 2017-07-13 |
United States Patent
Application |
20170198112 |
Kind Code |
A1 |
Mahon; William J. ; et
al. |
July 13, 2017 |
Method of Making Foam
Abstract
A method of making a foam from a polymerizable resin includes
the following steps. A thermally-activated initiator having a
temperature below the initiation temperature is combined with an
elevated-temperature solution having the polymerizable resin and
carbon dioxide at a temperature above a promoted temperature to
create a resulting mixture having a temperature above the promoted
temperature. The resulting mixture is expanded by decreasing the
pressure of the mixture to create a froth having a plurality of
cells formed by carbon dioxide that expanded out of solution. The
polymerizable resin within the froth is cured to create a foam.
Inventors: |
Mahon; William J.;
(Southbury, CT) ; Ruddy; Henry J.; (Sandy Hook,
CT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sealed Air Corporation (US) |
Charlotte |
NC |
US |
|
|
Family ID: |
49619830 |
Appl. No.: |
15/468816 |
Filed: |
March 24, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14080046 |
Nov 14, 2013 |
9637607 |
|
|
15468816 |
|
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61728932 |
Nov 21, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 222/1006 20130101;
C08J 2335/02 20130101; C08J 9/122 20130101; C08J 2203/06 20130101;
C08J 2333/08 20130101 |
International
Class: |
C08J 9/12 20060101
C08J009/12 |
Claims
1-20. (canceled)
21. A method of making a foam, the method comprising: (i) providing
a solution comprising: a polymerizable resin; a thermally-activated
initiator having a given promoted temperature; carbon dioxide; and
optionally a promoter, wherein the temperature of the solution is
below the promoted temperature of the initiator; (ii) expanding the
solution to create a froth comprising a plurality of cells formed
by carbon dioxide that expanded out of solution; and (iii) exposing
the froth to microwave radiation to heat the froth above the
promoted temperature of the initiator; and (iv) curing the
polymerizable resin to create a foam having a solidified matrix
encasing the plurality of cells.
22. The method of claim 21, wherein: the solution is provided by
mixing the polymerizable resin, the initiator, and carbon dioxide
in a mixing chamber at a pressure of at least 100 psig, preferably
any one of at least 200, 300, 350, 500, and 800 psig; and the
expanding step (ii) occurs in a dispensing chamber having a
pressure less than 100 psig.
23. The method of claim 21, further comprising dispensing the froth
from the dispensing chamber to create the foam of step (iv) outside
of the dispenser chamber.
24. The method of claim 21, wherein the method is conducted
continuously.
25. The method of claim 21, wherein the expanding step (ii) occurs
intermittently.
26. The method of claim 21, wherein the polymerizable resin
comprises triglyceride having acrylate functionality.
27. The method of claim 21, wherein the solution further comprises
co-reactant.
28. The method of claim 27, wherein the co-reactant comprises an
acrylate.
29. The method of claim 21, wherein the temperature of the solution
of the providing step (i) is at most 45.degree. C., preferably at
most any one of 40, 35, 25, and 20.degree. C.
30. The method of claim 21, wherein the exposing step (iii)
comprises directing microwave radiation toward a stream of the
froth as the stream passes through the bore of a housing.
31. The method of claim 21, wherein the solution of step (i)
comprises one or more promoters.
Description
[0001] The present application is a divisional of U.S.
Non-Provisional application Ser. No. 14/080,046 filed Nov. 14,
2013, which claims priority to U.S. Provisional Application No.
61/728,932 filed Nov. 21, 2012 and, which are both incorporated
herein in its entirety by reference.
[0002] The presently disclosed subject matter relates to methods of
making foam (i.e., cellular plastic), for example, foam produced
using one or more sustainably produced reactants.
BACKGROUND
[0003] It is known to produce foam from a reactive mixture of one
or more polyols and one or more isocyanates, for example as
disclosed in U.S. Pat. No. 6,034,197, which is incorporated herein
in its entirety by reference. Suitable systems for making and/or
dispensing such foams are described, for example, in U.S. Pat. Nos.
5,186,905; 5,255,847; 5,950,875; 6,811,059; 6,929,193; and
6,996,956, each of which is incorporated herein in its entirety by
reference. However, in some instances it may be desirable to make
foam without the need to use isocyanate reactants, such as those
used in formulating polyurethane foams.
SUMMARY
[0004] One or more embodiments of the presently disclosed subject
matter may address one or more of the aforementioned problems.
[0005] A method of making a foam from a polymerizable resin
includes the following steps. In step (i), a thermally-activated
initiator having a given initiation temperature and a given
promoted temperature, is provided. The temperature of the initiator
is below the initiation temperature. In step (ii), an
elevated-temperature solution having a given amount of the
polymerizable resin and carbon dioxide, and optionally promoter, is
provided. The temperature of the elevated-temperature solution is
above the promoted temperature. In step (iii), the initiator of
step (i) is combined at a mixing pressure with the solution of step
(ii) to form a mixture having a temperature above the promoted
temperature. In step (iv), the mixture is expanded by decreasing
the pressure of the mixture to below the mixing pressure to create
a froth having a plurality of cells formed by carbon dioxide that
expanded out of solution. In step (v), the polymerizable resin
within the froth is cured to create a solidified matrix encasing
the plurality of cells.
[0006] These and other objects, advantages, and features of the
presently disclosed subject matter will be more readily understood
and appreciated by reference to the detailed description and the
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a representative schematic diagram of an
embodiment of the presently disclosed subject matter;
[0008] FIG. 2 is a representative schematic diagram of an
alternative embodiment of the presently disclosed subject
matter;
[0009] FIG. 3 is a representative side elevation sectional view of
an embodiment of a device 30 of the presently disclosed subject
matter; and
[0010] FIG. 4 is a representative schematic diagram of another
alternative embodiment of the presently disclosed subject
matter.
[0011] Various aspects of the subject matter disclosed herein are
described with reference to the drawings. For purposes of
simplicity, like numerals may be used to refer to like, similar, or
corresponding elements of the various drawings. The drawings and
detailed description are not intended to limit the claimed subject
matter to the particular form disclosed. Rather, the intention is
to cover all modifications, equivalents, and alternatives falling
within the spirit and scope of the claimed subject matter.
DETAILED DESCRIPTION
[0012] Various embodiments of the presently disclosed subject
matter are directed to methods of making foam. In several
embodiments, a thermally-activated initiator is combined with a
solution comprising a polymerizable resin and carbon dioxide
dissolved in the polymerizable resin, optionally with
co-reactant.
Polymerizable Resin
[0013] "Polymerizable resin" as used herein refers to reactive
molecules having three or more sites of ethylenic unsaturation that
participate in forming covalent bonds during the free radical
polymerization (i.e., have a functionality of three or more) to
form larger molecules comprising multiples of the reactive
molecules.
[0014] The polymerizable resin may have a bio-carbon content of at
least 50%, for example at least 70%, where the percent bio-carbon
is defined as 100.times.(number of bio-derived carbon atoms/total
number of carbon atoms), where the bio-derived carbon atoms are
derived from biological sources.
[0015] The polymerizable resin may comprise one or more of any of
triacrylate and tetra-acrylate. Triacrylate is a molecule having
three acrylate functionality sites. Tetra-acrylate is a molecule
having four acrylate functionality sites. Useful triacrylates and
tetra-acrylates include, for example, one or more of
trimethylolpropane triacrylate, ethoxylated trimethylolpropane
triacrylate, pentaerythritol tetraacrylate, ethoxylated
pentaerythritol tetraacrylate, polyester triacrylate, polyester
tetra-acrylate, fatty acids and/or fatty acid esters having
acrylate functionality, and mono-, di-, and/or triglycerides having
acrylate functionality.
[0016] The polymerizable resin may comprise triglyceride having
acrylate functionality, for example, acrylated epoxidized
triglyceride. Useful triglyceride having acrylate functionality may
comprise triglyceride derived from plant, such as one or more of
any of soybean oil, linseed oil, castor oil, cotton oil, corn oil,
sunflower oil, palm oil, peanut oil, rapeseed oil, olive oil, and
canola oil. Useful triglyceride having acrylate functionality may
comprise triglyceride derived from animal, such as fish oil.
[0017] As is known in the art, the reactive sites (e.g., the carbon
double bonds in the fatty acid chains) of a triglyceride may be
epoxidized to create epoxidized sites, which may then be acrylated
(i.e., reacted with an acrylic acid, methacrylic acid, acrylate, or
methacrylate), for example, to create acrylated epoxidized
triglyceride, for example acrylated epoxidized soybean oil (AESO)
or acrylated epoxidized linseed oil (AELO). Useful triacrylates
having acrylate functionality, such as AESOs, are disclosed for
example in International Patent Application Publication
WO2013/077865 A1 published May 30, 2013 (from International Patent
Application PCT/US2011/61915) to Speer et al, which is incorporated
herein in its entirety by reference.
[0018] As used herein, "acrylate" includes acrylates,
methacrylates, and molecules having combinations of acrylate and
methacrylate functionalities. "Acrylate functionality" includes
functionality provided by any of acrylate and methacrylate
moieties. "Acrylate moieties" includes acrylate and methacrylate
moieties. As used in this context, "acrylate functionality" refers
to the number of acrylate moieties on the triglyceride molecule.
Useful triglyceride having acrylate functionality for use as
polymerizable resin may have an acrylate functionality of any one
of 3, at least 3, and 4.
[0019] The polymerizable resin may comprise unsaturated polyester
resin with ethylenic unsaturation stemming from maleic, fumaric,
and/or itaconic acids and/or anhydrides. The polymerizable resin
may comprise acrylated epoxidized novolac resins.
[0020] The polymerizable resin may comprise molecules having a
functionality of three in an amount of at least any of 50, 60, 70,
80, 90, and 95%; and/or at most any of 99, 95, 90, 80, 70, and 60%,
based on the weight of the polymerizable resin.
[0021] The polymerizable resin may comprise molecules having a
functionality of four in an amount of at least any of 5, 10, 15,
20, 30, 40, and 50%; and/or at most any of 60, 50, 40, 30, 20, 15,
and 10%, based on the weight of the polymerizable resin.
[0022] The polymerizable resin may comprise triglyceride having
acrylate functionality in an amount of at least any of 50, 60, 70,
80, 90, and 95%; and/or at most any of 99, 95, 90, 80, 70, and 60%,
based on the weight of the polymerizable resin.
Co-Reactants
[0023] A "co-reactant" is a molecule having two or fewer sites of
ethylenic unsaturation that participate in forming covalent bonds
during the free radical polymerization of the polymerizable resin
(i.e., have a functionality of two or one). The co-reactant may be
reactive diluent, that is, co-reactant that can act to lower the
viscosity of a solution comprising the polymerizable resin (i.e.,
act as a solvent or diluent for the polymerizable resin). A
co-reactant may be selected to improve one or more characteristics
of the cured polymerizable resin, such as tensile strength,
compressive strength, toughness, and/or modulus.
[0024] Useful co-reactants comprise one or more of styrene,
alpha-methyl styrene, vinyl toluene, diallyl phthalate, diallyl
isophthalate, diallyl maleate, and acrylate.
[0025] The co-reactant may comprise acrylate, that is, one or more
of monoacrylate and diacrylate. The co-reactant may comprise
monoacrylate, that is, molecules having a single acrylate
functionality site. Useful monoacrylates include one or more of
iso-bornyl acrylate, fatty alcohol monoacrylate (e.g., lauryl
acrylate), cyclohexyl monoacrylates, ethoxylated phenol
monoacrylates (e.g., four-mole ethoxylated nonyl phenol acrylate),
epoxy acrylates (e.g., glycidyl methacrylate), and acrylated fatty
acid ester.
[0026] The co-reactant may comprise diacrylate, that is, molecules
having two acrylate functionality sites. Useful diacrylates
include, for example, one or more of polyethylene glycol
diacrylates, polypropylene glycol diacrylates, bisphenol A
diacrylates, diacrylates derived from vegetable oil, and polyester
diacrylates.
[0027] Useful polyethylene glycol diacrylate include PEG 200
diacrylate, PEG 400 diacrylate, and PEG 1000 diacrylate where the
numbers represent the average molecular weight of the PEG
segment.
[0028] Useful polypropylene glycol diacrylates include dipropylene
glycol diacrylate, and tripropylene glycol diacrylate.
[0029] Useful bisphenol A diacrylates include ethoxylated bisphenol
A diacrylate, such as those having 2, 3, and 4 or more moles of
ethoxylation, and including bisphenol diacrylates and bisphenol A
dimethacrylates.
[0030] Useful polyester diacrylates include polyester segments
comprising aliphatic and aromatic moieties. When a more rigid foam
is desired, polyester segments can be chosen that have a glass
transition temperature (T.sub.g) that is greater than room
temperature. Similarly when a more flexible foam is desired the
polyester segments can be selected with a T.sub.g below room
temperature. Preferred polyester acrylates may include bio-carbon
content for example via the inclusion of poly(lactic acid)
segments.
[0031] The amount of co-reactant relative the polymerizable resin
may be at least any one of 5, 6, 7, 8, 10, 12, 15, 17, and 20
weight parts of the co-reactant; and/or at most any one of 90, 80,
70, 60, 55, 50, 40, and 30 weight parts of the co-reactant relative
to 100 weight parts of the polymerizable resin.
[0032] The co-reactant may comprise an amount of acrylate (e.g., an
amount of any of one or more of monoacrylate and/or diacrylate) of
at least, and/or at most, any of 10, 20, 30, 40, 50, 60, 70, 80,
90, 95, and 99%, based on the weight of the co-reactant. The
co-reactant may comprise monoacrylate, for example, of at least any
of 1, 5, 10, 15, and 20%; and/or at most any of 40, 30, 20, 10, and
5%, based on the weight of the co-reactant. The co-reactant may
comprise an amount of diacrylate, for example, of at least any of
6, 7, 8, 10, 12, 15, 17, and 20%; and/or at most any of 60, 55, 50,
40, 30, 20, and 10%, based on the weight of the co-reactant.
Carbon Dioxide
[0033] The solution comprising polymerizable resin comprises carbon
dioxide dissolved in the polymerizable resin. The solubility of
carbon dioxide with polymerizable resin will typically increase
with increasing pressure. One or more additional gases may be
incorporated with carbon dioxide in the method, for example,
nitrogen and/or water.
Initiator
[0034] The thermally-activated initiator (i.e., "initiator") is an
agent used as a source of free radicals to start the polymerization
reaction of the polymerizable resin. A thermally-activated
initiator is one that thermally decomposes to produce the radicals
that initiate the polymerization reaction. The half life of an
initiator is characterized as the time required to reduce the
original initiator concentration of a solution by 50%, at a given
temperature. As used herein, the "initiation temperature" of a
thermally-activated initiator is the temperature corresponding to a
ten-hour half life of the initiator using benzene solvent (0.2M
concentration) or equivalent. For example, the initiation
temperature of dilauroyl peroxide (i.e., without promoter) is
62.degree. C.
[0035] One or more promoters (also known as accelerators) may
optionally be used to increase the activity of the initiator. As
used herein, the "promoted temperature" of a thermally-activated
initiator is the temperature corresponding to a ten-hour half life
of the initiator using benzene solvent (0.2M concentration) or
equivalent, in the presence of the promoter in the same weight
ratio (weight parts promoter to million weight parts initiator)
that is used in the method. If no promoter is used in the method,
then the "promoted temperature" is the same temperature as the
"initiation temperature."
[0036] Useful thermally-activated initiators include one or more of
azo compounds and organic peroxides, such as one or more of any of
diacyl peroxides (such as dilauroyl peroxide or dibenzoyl peroxide)
dialkyl peroxides (such as dicumyl peroxide), tert-butyl benzoyl
peroxide, peroxyesters, peroxydicarbonates, hydroperoxides,
peroxymonocarbonates, peroxyketals, and methyl ethyl ketone
peroxide. Useful peroxides and their corresponding ten-hour half
life temperatures are disclosed, for example, in U.S. Pat. No.
4,143,099 to Duncan and U.S. Pat. No. 4,607,087 to Moriya et al,
each of which is incorporated herein in its entirety by
reference.
[0037] The thermally-activated initiator may comprise more than one
type of thermally-activated initiator, for example, a first
thermally-activated initiator and a second thermally-activated
initiator, where the initiation temperature of the first initiator
is lower than the second initiator, for example, lower by any of
the following: 10.degree. C., 20.degree. C., and 30.degree. C.
[0038] The amount of thermally-activated initiator may be at least,
and/or at most, any one of 0.1, 0.5, 1, 1.5, 2, 3, 4, and 5 weight
parts thermally-activated initiator relative 100 weight parts of
the polymerizable resin.
[0039] One or more promoters (also know as accelerators) may be
used in combination with the initiator. Useful promoters include
transition metal salts and tertiary amines, such as aromatic
tertiary amines such as N-(2-hydroxylethyl)-N-methyl-p-toluidine.
Useful amounts of promoter range from at least any of 100, 200, and
300 weight parts promoter per million weight parts initiator;
and/or at most any of 1,200; 1,000; 800; and 500 weight parts
promoter per million weight parts initiator.
Additional Components
[0040] The method may optionally comprise incorporating one or more
additional components in any of the solutions and/or mixtures.
[0041] One or more surfactants may optionally be incorporated into
any of the solutions and/or mixtures of the methods. Useful
surfactants include any of one or more of polysiloxanes (i.e.,
silicone surfactants and ethoxylated polysiloxane), ethoxylated
fatty acids, salts of fatty acids, ethoxylated fatty alcohols,
salts of sulfonated fatty alcohols, and fatty acid ester sorbitan
ethoxylates (e.g., polysorbates available from Croda under the
Tween trade name).
[0042] The amount of surfactant may be at least any one of 0.01,
0.05, 0.1, 0.2, 0.3, and 0.4 weight parts surfactant, and/or at
most any of 3, 1, 0.7, and 0.4 weight parts surfactant, relative
100 weight parts of the polymerizable resin.
[0043] One or more additives may optionally be incorporated into
any of the solutions and/or mixtures of the methods. Useful
additives include one or more of any of nucleating and/or
reinforcing agent (e.g., cellulosic material such as cellulose
fiber, wood pulp, powdered paper, starch, natural clays and
modified intercalated clays, and nanoparticles), flame retardant
(e.g., ATH), aging modifier (e.g., fatty acid ester, fatty acid
amide, hydroxyl amide), pigment, colorant, antioxidant, stabilizer,
fragrance, and odor masking agent. The nucleating agent may assist
in controlling the size of foam cells. The stabilizer may enhance
dimensional stability of the foam. Exemplary stabilizers include
amides and esters of C(10-24)fatty acids, stearyl stearamide,
glyceromonostearate, glycerol monobehenate, and sorbitol
monostearate.
Manufacture of the Foam
[0044] In an embodiment of a method of making the foam (FIG. 1), an
elevated-temperature solution 10 is provided for example from
conditioning vessel 12, the elevated temperature solution having a
given amount of the polymerizable resin and carbon dioxide,
optionally together with co-reactant and/or promoter. The
temperature of the elevated-temperature solution is above the
promoted temperature (defined above) of the thermally-activated
initiator 14, which may be separately provided. For example, the
temperature of the elevated-temperature solution may be at least
any one of 25, 35, 50, 75, 100, 120, 150, and 175.degree. C. The
elevated-temperature solution may be made in conditioning vessel 12
at elevated pressure, for example, a pressure of at least any one
of 100, 200, 300, 350, 500, and 800 psig. The components of the
elevated-temperature solution are preferably mixed sufficiently to
distribute and disperse the components using methods known to those
of skill in the art. For example, the components may be mixed into
solution by stirring in a mixing vessel or extruding in an
extrusion mixer. The carbon dioxide may be infused into the
solution using an infuser. When the method incorporates the use of
a promoter, the temperature of the elevated-temperature solution
may be provided toward the lower end of the range provided
above.
[0045] The thermally-activated initiator 14 is provided at a
temperature below its initiation temperature (defined above). For
example, the initiator may be provided at a temperature of at most
any of 20, 25, 35, 40, and 45.degree. C. The elevated-temperature
solution 10 and the thermally-activated initiator 14 may be
combined in a mixing chamber 16 at a mixing pressure of, for
example, at least any one of 100, 200, 300, 350, 500, and 800 psig,
to form a resulting mixture having a temperature above the promoted
temperature of the thermally-activated initiator, for example, at a
mixing temperature of any one of at least 10, 20, 30, 40, 50, and
60.degree. C. above the promoted temperature of the
thermally-activated initiator. As a result, the curing reaction
begins upon mixing, for example, within the mixing chamber 16.
[0046] In another embodiment of the method (FIG. 2), the
thermally-activated initiator may be provided for example from
conditioning vessel 18 as a component of a lower-temperature
solution 20 comprising a supplemental amount of the polymerizable
resin and carbon dioxide, and optionally with co-reactant. The
temperature of the lower-temperature solution is below the
initiation temperature of the initiator. For example, the
lower-temperature solution may be provided at a temperature of at
most any of 20, 25, 35, 40, and 45.degree. C. The lower-temperature
solution may be made in conditioning vessel 18 at elevated
pressure, for example, a pressure of at least any one of 100, 200,
300, 350, 500, and 800 psig, using any of the techniques described
above in reference to the elevated-temperature solution.
[0047] The elevated-temperature solution 10 and the
lower-temperature solution 20 may be combined at a mixing pressure
of, for example, at least any one of 100, 200, 300, 350, 500, and
800 psig, for example in mixing chamber 16 to form a resulting
mixture having a temperature above the promoted temperature of the
thermally-activated initiator, for example, at a mixing temperature
of any one of at least 10, 20, 30, 40, 50, and 60.degree. C. above
the promoted temperature of the thermally-activated initiator. As a
result, the curing reaction begins upon mixing, for example, within
the mixing chamber 16.
[0048] The step of combining the elevated-temperature solution 10
and the thermally-activated initiator 14 (or the lower-temperature
solution 20) may occur in mixing chamber 16. For example, a stream
of the initiator 14 may be impinged or entrained with a stream of
the elevated-temperature solution 10. (FIG. 1.) Also by example, a
stream of the lower-temperature solution 20 may be impinged or
entrained with a stream of the elevated-temperature solution 10.
(FIG. 2.)
[0049] Simultaneously or soon after the mixing, the resulting
mixture 26 is expanded to create a froth 22, for example, by a
sudden reduction in pressure. The mixture may be expanded to the
froth by expanding from, for example, any one of the mixing
pressures listed in the previous paragraphs, to a pressure below
the mixing pressure, for example, ambient atmospheric pressure. The
pressure may be reduced by at least any of the following: 100, 200,
300, 400, 500, and 800 psi.
[0050] A "froth" is the expanded mixture at the initial period of
the curing process (i.e., polymerization process) comprising the
polymerizable resin, co-reactants, and other components and a
plurality of cells within the mixture created by the carbon dioxide
and other gases that have come out of solution or have vaporized in
response to the decrease in pressure. The froth exists before
curing has been completed.
[0051] The step of expanding the resulting mixture 26 to create the
froth 22 may occur by discharging the mixture directly from the
mixing chamber 16 to ambient conditions (not illustrated), or
alternatively by discharging the mixture into a dispensing chamber
24. In the latter case, the froth 22 may then be discharged from
the dispensing chamber 24 to allow the curing process to proceed to
completion and create the foam outside of the dispensing
chamber.
[0052] The polymerizable resin along with any of the co-reactants
within the froth are cured to create a solidified matrix
surrounding or encasing the cellular structure of the plurality of
cells to create the foam. Where the thermally-activated initiator
comprises a first thermally-activated initiator that activates at a
first initiation temperature lower than a second initiation
temperature of a second thermally-activated initiator, then the
temperature of the mixture or froth may be elevated in a controlled
fashion to help control the rate of the curing reaction, as well as
potentially extend the curing reaction. Typically the curing is
exothermic, so that the temperature of the system will typically
rise after initiation of the curing reaction.
[0053] In an embodiment of the presently disclosed subject matter,
FIG. 3 illustrates a device 30 for making and dispensing froth 22.
Inlet 32 provides an inlet for the elevated-temperature solution,
for example, from its conditioning vessel (not illustrated). Inlet
34 provides an inlet for the thermally-activated initiator or the
lower-temperature solution (comprising initiator) from its
conditioning vessel (not illustrated). The flow of the
elevated-temperature solution may be controlled by valve 36; and
the flow of the initiator or lower-temperature solution may be
controlled by valve 38. The elevated-temperature solution may flow
from the inlet 32 as controlled by valve 36 through conduit 40 to
and through mixing chamber inlet 44 to enter the mixing chamber 16.
The initiator or lower-temperature solution may flow from the inlet
34 as controlled by valve 38 through conduit 42 to and through
mixing chamber inlet 44 to enter the mixing chamber 16. Although
illustrated as a single mixing chamber inlet 44, alternatively each
of the conduits 40 and 42 may have an independent inlet (not
illustrated) into the mixing chamber 16.
[0054] Mixing chamber valving rod 46 is movable within mixing
chamber 16 from an open position, as shown in FIG. 3, in which
inlet 44 is open, to a closed position (not illustrated) in which
the inlet 44 is closed. In the closed position, valving rod 46 may
extend to the exit 48 of mixing chamber 16. The movement of the
mixing chamber valving rod may be controlled by an actuator (not
illustrated). In the open position, the valving rod 46 is withdrawn
so that it does not block the inlet 44 so that the streams from
conduits 40 and 42 may enter into and mix with and/or impinge upon
each other within the mixing chamber 16. In the closed position,
the valving rod 46 extends to cover and block (i.e., close) the
inlet 44 so that there is no flow of material from the conduits 40
and 42.
[0055] The mixing chamber 16 is in fluid communication with the
dispensing chamber 24 through exit 48. The size of chamber exit 48
(e.g., an exit port) is selected to restrict the rate of flow of
mixture from the mixing chamber 16 and to retain an elevated
pressure within the mixing chamber 16 by virtue of the constricted
flow. As the mixture passes through exit 48, the pressure drops,
for example to less than the mixing pressure, for example less than
100 psig, for example to ambient atmospheric pressure. When the
mixing chamber valving rod 46 is extended to the closed position,
the valving rod may block exit 48.
[0056] Dispensing chamber valving rod 50 is moveable within
dispensing chamber 24 from an open position, as shown in FIG. 3, in
which exit 48 is open, to a closed position (not illustrated) in
which exit 44 is closed. In the closed position, dispensing chamber
valving rod 50 may extend to the outlet 52 of the dispensing
chamber 24. The movement of the dispensing chamber valving rod 50
may be controlled by an actuator (not illustrated). In the open
position, the valving rod 50 is withdrawn so that it does not block
the exit 48 from the mixing chamber so that the mixture from the
mixing chamber may flow from the mixing chamber 16 through exit 48
into dispensing chamber 24, where it may expand into a froth. In
the closed position, the valving rod 50 extends to cover and block
(i.e., close) the chamber exit 48 so that there is no flow of
material from the mixing chamber.
[0057] The residue of the mixture 26 from the mixing chamber 16 and
residue of the froth 22 from the dispensing chamber 24 may be
purged, for example, mechanically purged by a the extension of the
mixing chamber valving rod 46 (e.g., to the closed position) and
the extension of dispensing chamber valving rod 50 (e.g., to the
closed position), respectively, to push the residue from the
respective chamber.
[0058] In operation, the device 30 may move through a
mixing/dispensing cycle and a termination cycle to produce froth in
desired amounts upon demand. For example, during the
mixing/dispensing cycle the mixing chamber valving rod 46 is in the
open position and the dispensing chamber valving rod 50 is in the
open position, so that the elevated-temperature solution and the
initiator (or the lower-temperature solution comprising the
initiator) may flow into the mixing chamber 16 to impinge and mix
with each other to create a mixture at a relatively higher mixing
pressure, and flow through the restricted exit 48 into dispensing
chamber 24 to expand into the relatively lower pressure (i.e.,
below the mixing pressure) within the dispensing chamber 24 where
the mixture expands to create a froth 22 that flows out exit 52 as
the froth expands.
[0059] After an appropriate time, the device is moved to the
termination cycle, in which the mixing chamber valving rod 46 is
moved to the closed position, to purge the mixing chamber so that
the remainder of mixture 26 within mixing chamber 16 moves (e.g.,
is pushed) from the mixing chamber 16 through the exit 48. The
dispensing chamber valving rod 50 is then moved to the closed
position to purge the dispensing chamber 24 by pushing the
remainder of the froth from the dispensing chamber 24 out of the
outlet 52 of the dispensing chamber.
[0060] The froth exits the device 30 where it is cured outside of
the device 30 to create the foam having a solidified matrix
encasing a plurality of cells. To begin the cycle again, the
dispensing chamber valving rod 50 is moved to the open position and
the mixing chamber valving rod 46 is moved to the open
position.
[0061] Useful chambers, ports, valving rods, and related equipment
for mixing and dispensing reactant streams of chemicals in the
manufacture of foam are disclosed, for example, in U.S. Pat. No.
5,186,905 to Bertram et al; U.S. Pat. No. 5,950,875 to Lee et al;
U.S. Pat. No. 6,811,059 to Piucci et al; and U.S. Pat. No.
6,996,956 to Sperry et al; each of which is incorporated herein in
its entirety by reference.
[0062] In another embodiment of a method of making foam (FIG. 4), a
solution 60 is provided comprising the polymerizable resin, the
thermally-activated initiator, and carbon dioxide, optionally
together with co-reactants and/or promoter. The solution 60 may be
made by mixing the components in mixing chamber 16 at an elevated
pressure, for example, a pressure of at least any one of 100, 200,
300, 350, 500, and 800 psig. The components of the solution are
preferably mixed sufficiently to distribute and disperse the
components using methods known to those of skill in the art. For
example, the components may be mixed into solution by stirring in a
mixing vessel or extruding in an extrusion mixer. The carbon
dioxide and other gases may be infused into the solution using an
infuser.
[0063] The solution 60 is provided at a temperature below the
promoted temperature of the initiator. For example, the solution
may be provided at a temperature of at most any of 20, 25, 35, 40,
and 45.degree. C. The solution 60 is expanded to create a froth
comprising a plurality of cells formed by carbon dioxide that
expanded out of solution, for example, by a sudden reduction in
pressure. The solution may be expanded to the froth by expanding
from, for example, any one of the elevated pressures listed in the
previous paragraphs, to a pressure below the elevated pressure, for
example, ambient atmospheric pressure. The pressure may be reduced
by at least any of the following: 100, 200, 300, 400, 500, and 800
psi. The expansion of the solution may occur in a dispensing
chamber 24 at the reduced pressure, for example, a pressure of less
than 100 psig or at ambient atmospheric pressure.
[0064] Simultaneously or soon after the expansion, the froth 22 is
exposed to microwave radiation at station 62 to heat the froth
above the promoted temperature of the initiator. This initiates the
curing reaction of the polymerizable resin and optional
co-reactants within the froth to create a foam having a solidified
matrix encasing the plurality of cells. The step of exposing to
microwave radiation may occur by directing microwave radiation
toward a stream of the froth as the stream passes through the bore
of a housing. The froth may be dispensed from the dispensing
chamber to create the foam outside of the dispenser chamber. The
microwave station may comprise a microwave oven, such that the
froth may be passed through the microwave oven.
[0065] Additional disclosures regarding the embodiments related to
FIG. 4 are made in the following sentences. [0066] A. A method of
making a foam, the method comprising: [0067] (i) providing a
solution comprising: [0068] a polymerizable resin; [0069] a
thermally-activated initiator having a given promoted temperature;
[0070] carbon dioxide; and [0071] optionally a promoter, wherein
the temperature of the solution is below the promoted temperature
of the initiator; [0072] (ii) expanding the solution to create a
froth comprising a plurality of cells formed by carbon dioxide that
expanded out of solution; and [0073] (iii) exposing the froth to
microwave radiation to heat the froth above the promoted
temperature of the initiator; and [0074] (iv) curing the
polymerizable resin to create a foam having a solidified matrix
encasing the plurality of cells. [0075] B. The method of sentence A
wherein: [0076] the solution is provided by mixing the
polymerizable resin, the initiator, and carbon dioxide in a mixing
chamber at a pressure of at least 100 psig, preferably any one of
at least 200, 300, 350, 500, and 800 psig; and [0077] the expanding
step (ii) occurs in a dispensing chamber having a pressure less
than 100 psig. [0078] C. The method of sentence B further
comprising dispensing the froth from the dispensing chamber to
create the foam of step (iv) outside of the dispenser chamber.
[0079] D. The method of any one of sentences A to C wherein the
method is conducted continuously. [0080] E. The method of any one
of sentences A to C wherein the expanding step (ii) occurs
intermittently. [0081] F. The method of any one of sentences A to E
wherein the polymerizable resin comprises triglyceride having
acrylate functionality. [0082] G. The method of any one of
sentences A to F wherein the solution further comprises
co-reactant. [0083] H. The method of sentence G wherein the
co-reactant comprises an acrylate. [0084] I. The method of any one
of sentences A to H wherein the temperature of the solution of the
providing step (i) is at most 45.degree. C., preferably at most any
one of 40, 35, 25, and 20.degree. C. [0085] J. The method of any
one of sentences A to I wherein the exposing step (iii) comprises
directing microwave radiation toward a stream of the froth as the
stream passes through the bore of a housing. [0086] K. The method
of any one of sentences A to J wherein the solution of step (i)
comprises one or more promoters.
[0087] With any of the embodiments disclosed herein, the
manufacture of the foam may occur relatively continuously.
Alternatively, the manufacture of the foam may occur
intermittently, for example, by combining incremental portions of
the elevated-temperature solution with the initiator or the
lower-temperature solution, such that the manufacture occurs to
produce only desired portions of the foam "on demand."
Foam
[0088] The resulting foam (i.e., cellular plastic) may have a
density of at most, and/or at least, any one of 0.25, 0.5, 1.0,
1.5, 2.0, 2.5, 3.0, 4.0, 6.0, and 7.0 pounds per cubic foot (pcf).
For protective packaging (e.g., cushioning) applications, lower
densities are preferred. Unless otherwise noted, the density of the
foam as used herein is the apparent density measured according to
ASTM D1622-08, which is incorporated herein in its entirety by
reference.
[0089] The resulting foam may have a compressive strength at 50%
strain of at least any of the following: 0.5, 0.8, 1.0, 1.5, 2.0,
and 2.5 psi, for example at from 10 to 50% compression. As used
herein, the compressive strength is measured according to ASTM
1621-00, as modified by reference to 50% strain.
[0090] The foam may have a configuration, for example, of any of a
sheet, plank, slab, block, board, and molded shape. The foam may be
used for any one or more of void fill, blocking or bracing, thermal
insulation, cushioning, sound insulation or vibration
dampening.
[0091] In preferred embodiments, the mixtures used to make the foam
are free of isocyanate reactants, such as those used in formulating
polyurethane foams, so that the final foam of the present
disclosure is free from isocyanates or isocyanate residues.
[0092] Any numerical value ranges recited herein include all values
from the lower value to the upper value in increments of one unit
provided that there is a separation of at least 2 units between any
lower value and any higher value. As an example, if it is stated
that the amount of a component or a value of a process variable
(e.g., temperature, pressure, time) may range from any of 1 to 90,
20 to 80, or 30 to 70, or be any of at least 1, 20, or 30 and/or at
most 90, 80, or 70, then it is intended that values such as 15 to
85, 22 to 68, 43 to 51, and 30 to 32, as well as at least 15, at
least 22, and at most 32, are expressly enumerated in this
specification. For values that are less than one, one unit is
considered to be 0.0001, 0.001, 0.01 or 0.1 as appropriate. These
are only examples of what is specifically intended and all possible
combinations of numerical values between the lowest value and the
highest value enumerated are to be considered to be expressly
stated in this application in a similar manner.
[0093] The above descriptions are those of preferred embodiments of
the invention. Various alterations and changes can be made without
departing from the spirit and broader aspects of the invention as
defined in the claims, which are to be interpreted in accordance
with the principles of patent law, including the doctrine of
equivalents. Except in the claims and the specific examples, or
where otherwise expressly indicated, all numerical quantities in
this description indicating amounts of material, reaction
conditions, use conditions, molecular weights, and/or number of
carbon atoms, and the like, are to be understood as modified by the
word "about" in describing the broadest scope of the invention. Any
reference to an item in the disclosure or to an element in the
claim in the singular using the articles "a," "an," "the," or
"said" is not to be construed as limiting the item or element to
the singular unless expressly so stated. The definitions and
disclosures set forth in the present Application control over any
inconsistent definitions and disclosures that may exist in an
incorporated reference. All references to ASTM tests are to the
most recent, currently approved, and published version of the ASTM
test identified, as of the priority filing date of this
application. Each such published ASTM test method is incorporated
herein in its entirety by this reference.
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