U.S. patent application number 11/039019 was filed with the patent office on 2005-08-18 for inkjet inks containing crosslinked polyurethanes.
Invention is credited to Bauer, Richard Douglas, Berge, Charles T., Li, Xiaoqing.
Application Number | 20050182154 11/039019 |
Document ID | / |
Family ID | 34807142 |
Filed Date | 2005-08-18 |
United States Patent
Application |
20050182154 |
Kind Code |
A1 |
Berge, Charles T. ; et
al. |
August 18, 2005 |
Inkjet inks containing crosslinked polyurethanes
Abstract
Inkjet inks are described that have, as a principal component, a
crosslinked polyurethane dispersoid binder additive. These inks can
be used for printing on different media, and are particularly
suitable for printing on textiles.
Inventors: |
Berge, Charles T.;
(Wilmington, DE) ; Li, Xiaoqing; (Newark, DE)
; Bauer, Richard Douglas; (Kennett Square, PA) |
Correspondence
Address: |
E I DU PONT DE NEMOURS AND COMPANY
LEGAL PATENT RECORDS CENTER
BARLEY MILL PLAZA 25/1128
4417 LANCASTER PIKE
WILMINGTON
DE
19805
US
|
Family ID: |
34807142 |
Appl. No.: |
11/039019 |
Filed: |
January 18, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60537880 |
Jan 21, 2004 |
|
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|
Current U.S.
Class: |
523/160 ;
523/161 |
Current CPC
Class: |
C09D 11/40 20130101;
B41J 2/01 20130101; C09D 11/30 20130101; B41M 5/0088 20130101; Y10T
428/24802 20150115; B41M 5/0023 20130101; B41M 5/0047 20130101;
C09D 11/322 20130101; C09D 11/326 20130101; B41J 2/21 20130101;
D06P 5/30 20130101 |
Class at
Publication: |
523/160 ;
523/161 |
International
Class: |
C03C 017/00; C09D
011/00 |
Claims
1. An inkjet ink composition comprising an aqueous vehicle, a
colorant and a crosslinked polyurethane dispersoid, wherein the
colorant is soluble or dispersible in the aqueous vehicle, and
wherein the weight ratio of crosslinked polyurethane to colorant is
at least about 1.0.
2. The inkjet ink composition of claim 1, wherein the ink comprises
from about 0.1 to about 30% by weight of the colorant, based on the
total weight of the ink.
3. The inkjet ink composition of claim 1, wherein the ink comprises
more than about 1% to about 30% by weight (solids basis) of the
crosslinked polyurethane dispersoid, based on the total weight of
the ink.
4. The inkjet ink composition of claim 1, wherein the amount of
crosslinking in the crosslinked polyurethane is greater than about
1% (THF insolubles test).
5. The inkjet ink composition of claim 1, wherein the amount of
crosslinking in the crosslinked polyurethane is less than about 50%
(THF insolubles test).
6. The inkjet ink composition of claim 1, wherein the ink comprises
from about 0.1 to about 30% by weight of the colorant, and more
than about 1% to about 30% by weight (solids basis) of the
crosslinked polyurethane dispersoid, based on the total weight of
the ink; and the amount of crosslinking in the crosslinked
polyurethane is greater than about 1% and less than about 50% (THF
insolubles test).
7. The inkjet ink composition of claim 1, having a surface tension
in the range of about 20 dyne/cm to about 70 dyne/cm, and a
viscosity is in the range of about 1 cP to about 30 cP at
25.degree. C.
8. The inkjet ink composition of claim 1, wherein the crosslinked
polyurethane has incorporated therein hydrophilic functionality to
the extent required to maintain a stable dispersion of the polymer
in the aqueous vehicle.
9. The inkjet ink composition of claim 1, wherein the colorant
comprises a pigment.
10. An inkjet ink set comprising at least three differently colored
inkjet inks, wherein at least one of the inks is an inkjet ink
composition comprising an aqueous vehicle, a colorant and a
crosslinked polyurethane dispersoid, wherein the colorant is
soluble or dispersible in the aqueous vehicle, and wherein the
weight ratio of crosslinked polyurethane to colorant is at least
about 1.0.
11. The inkjet ink set of claim 10, wherein the inkjet ink
composition comprises from about 0.1 to about 30% by weight of the
colorant, and more than about 1% to about 30% by weight (solids
basis) of the crosslinked polyurethane dispersoid, based on the
total weight of the ink; and the amount of crosslinking in the
crosslinked polyurethane is greater than about 1% and less than
about 50% (THF insolubles test).
12. The inkjet ink set of claim 11, wherein the inkjet ink
composition has a surface tension in the range of about 20 dyne/cm
to about 70 dyne/cm, and a viscosity is in the range of about 1 cP
to about 30 cP at 25.degree. C.
13. The inkjet ink set of claim 10, wherein the crosslinked
polyurethane has incorporated therein hydrophilic functionality to
the extent required to maintain a stable dispersion of the polymer
in the aqueous vehicle.
14. The inkjet ink set of claim 10, wherein the colorant comprises
a pigment.
15. The inkjet ink set of claim 10, wherein ink set comprises: (a)
a first colored ink comprising a first aqueous vehicle, a first
colorant and a first crosslinked polyurethane dispersoid, wherein
the first colorant is soluble or dispersible in the first aqueous
vehicle, and wherein the weight ratio of the first polyurethane
dispersoid to first colorant is at least about 1.0; (b) a second
colored ink comprising a second aqueous vehicle, a second colorant
and a second crosslinked polyurethane dispersoid, wherein the
second colorant is soluble or dispersible in the second aqueous
vehicle, and wherein the weight ratio of the second polyurethane
dispersoid to second colorant is at least about 1.0; and (c) a
third colored ink comprising a third aqueous vehicle, a third
colorant and a third crosslinked polyurethane dispersoid, wherein
the third colorant is soluble or dispersible in the third aqueous
vehicle, and wherein the weight ratio of the third polyurethane
dispersoid to third colorant is at least about 1.0.
16. The inkjet ink set of claim 15, wherein the first colored ink
is a cyan ink, the second colored ink is a magenta ink and the
third colored ink is a yellow ink.
17. The inkjet ink set of claim 15, further comprising (d) a fourth
colored ink comprising a fourth aqueous vehicle, a fourth colorant
and a fourth crosslinked polyurethane dispersoid, wherein the
fourth colorant is soluble or dispersible in the fourth aqueous
vehicle, and wherein the weight ratio of the fourth polyurethane
dispersoid to fourth colorant is at least about 1.0.
18. The inkjet ink set of claim 17, wherein the fourth colored ink
is a black ink.
19. A method for inkjet printing onto a substrate, comprising the
steps of: (a) providing an inkjet printer that is responsive to
digital data signals; (b) loading the printer with a substrate to
be printed; (c) loading the printer with an inkjet ink composition
comprising an aqueous vehicle, a colorant and a crosslinked
polyurethane dispersoid, wherein the colorant is soluble or
dispersible in the aqueous vehicle, and wherein the weight ratio of
crosslinked polyurethane to colorant is at least about 1.0.; and
(d) printing onto the substrate using the ink in response to the
digital data signals.
20. The method of claim 19, wherein the printer is loaded with an
inkjet ink set comprising at least three differently colored inkjet
inks, wherein at least one of the inks is an inkjet ink composition
comprising an aqueous vehicle, a colorant and a crosslinked
polyurethane dispersoid, wherein the colorant is soluble or
dispersible in the aqueous vehicle, and wherein the weight ratio of
crosslinked polyurethane to colorant is at least about 1.0; and
wherein the printing onto the substrate uses the inkjet ink
set.
21. The method of claim 19, wherein the substrate is a textile.
22. The method of claim 21, wherein the printed substrate is post
treated with a combination of heat and pressure.
23. The method of claim 21, wherein the printed textile has a wash
fastness of at least 2.0 and a stain rating of at least 3.3 (as
measured in accordance with AATCC Test Method 61-1996 as the 2A
test).
24. An inkjet printed textile inkjet printed with a pigmented
inkjet ink, said printed textile having a wash fastness of at least
2.0 and a stain rating of at least 3.0 (as measured in accordance
with AATCC Test Method 61-1996 as the 2A test).
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.119
from U.S. Provisional Application Ser. No. 60/537,880 (filed Jan.
21, 2004), the disclosure of which is incorporated by reference
herein for all purposes as if fully set forth.
[0002] This application is related to commonly owned U.S.
application Ser. No. __/___,___, concurrently filed herewith,
entitled "Inkjet Inks Containing Crosslinked Polyurethanes", which
also claims priority under 35 U.S.C. .sctn.119 from U.S.
Provisional Application Ser. No. 60/537,880 (filed Jan. 21,
2004).
BACKGROUND OF THE INVENTION
[0003] This invention pertains to inkjet inks, more specifically to
pigmented inkjet inks containing crosslinked polyurethane
dispersoid binders, which are particularly suitable for textile
printing.
[0004] Inkjet recording is a printing method wherein droplets of
ink are ejected through fine nozzles to form letters or figures on
the surface of recording media. Inks used in such recording are
subject to rigorous demands including, for example, good dispersion
stability, ejection stability, and good fixation to media.
[0005] Both dyes and pigments have been used as colorants for
inkjet inks. While dyes typically offer superior color properties
compared to pigments, they tend to fade quickly and are more prone
to rub off. Inks comprising pigments dispersed in aqueous media are
advantageously superior to inks using water-soluble dyes in
water-fastness and light-fastness of printed images.
[0006] Pigments suitable for aqueous inkjet inks are in general
well known in the art. Traditionally, pigments are stabilized by
dispersing agents, such as polymeric dispersants or surfactants, to
produce a stable dispersion of the pigment in the vehicle. Other
additives to the ink modify the ink to match the needs for the
target printed system, which includes the media.
[0007] Digital printing methods such as inkjet printing are
becoming increasingly important for the printing of textiles and
offer a number of potential benefits over conventional printing
methods such as screen printing. Digital printing eliminates the
set up expense associated with screen preparation and can
potentially enable cost-effective short run production. Inkjet
printing furthermore allows visual effects, such as tonal gradients
and repeat of printed patterns, that cannot be practically achieved
with a screen printing process. Especially in the case of the
production of pattern originals it is possible to respond to a
change in requirements within a significantly shorter period of
time.
[0008] Suitable such digital printing systems for textiles are
disclosed, for example, in commonly owned US20030128246 and
US20030160851, the disclosures of which are incorporated by
reference herein for all purposes as if fully set forth. Even as
inkjet hardware improvements are made to increase printing speeds,
adoption of inkjet printing in the textile industry will be impeded
if methods to also improve colorfastness are not found.
[0009] U.S. Pat. No. 4,597,794 discloses inkjet ink formulations
suitable for textile, with the ink formulation dispersion medium
containing a polymer having both an ethylenically unsaturated
carboxylic acid substituent as a hydrophilic portion and an
aromatic ring substituent as a hydrophobic portion. Wash fastness
was described as excellent for fabrics were imaged with this ink
and set by heating at 150.degree. C. for five minutes.
[0010] U.S. Pat. No. 5,897,694 discloses inkjet ink formulations
comprising, as an additive, a transition metal chelate. These inks
are said to provide improved wash fastness.
[0011] U.S. Pat. No. 5,958,561 discloses an ink/textile combination
wherein the textile is pretreated with a crosslinkable
thermoplastic polymer and then imaged with an aqueous ink and cured
at temperatures of 100-190.degree. C. Improved washfastness was
reported.
[0012] U.S. Pat. No. 6,146,769 discloses an ink/textile combination
wherein a water-soluble interactive polymer, in at least one of the
inks or on the textile, is said to help bind the particulate
colorant and provide wash fastness.
[0013] Japanese laid-open patent Hei 9-143407 discloses an inkjet
ink with thermoset resin which is imaged on fabric and fixed by
heating at 130.degree. C. The image is said to be water
resistant.
[0014] Japanese laid open patent Hei 8-283636 discloses an inkjet
ink with specified resin emulsions having high Tg. Fabric imaged
with this ink is fixed at elevated temperature to provide
washfastness.
[0015] WO03/029362 discloses a pigmented inkjet ink suitable for
textiles comprising an emulsion polymer and a crosslinking agent
which is suitable for cross linking the emulsion polymer. The
disclosure suggests that the use of the described crosslinking
agent improves dry and wash fastness.
[0016] U.S. Pat. No. 6,034,154 discloses polymer fine particles,
each polymer fine particle containing a colorant. One of the
candidate polymers making up the polymer portion of the fine
particle is described as a crosslinked polyurethane.
[0017] U.S. Pat. No. 6,136,890 describes pigmented inks that
contain pigments and polyurethane dispersants that stabilize the
pigments. The pigment is dispersed by the polyurethane via
dispersing techniques used to achieve a stabile pigment
dispersion.
[0018] US20030105187 describes a water-based pigmented ink for use
in inkjet printing (on paper and transparencies media). The ink
consists of a pigment and a latex, of which uncrosslinked
polyurethanes are listed as candidate latexes.
[0019] WO03/029318 describes polyurethane block copolymers as
dispersants for inks. These polyurethanes are crosslinked prior to
inversion (addition of water to produce the polyurethane
dispersion) not during or after inversion. There is also
crosslinking derived from the added melamine crosslinker which is
only effective at high temperatures and/or acidic conditions that
occur at the time of the textile treatments after printing.
[0020] The disclosures of all of the above-identified publications
are incorporated by reference for all purposes as if fully set
forth.
[0021] A disadvantage of inkjet printing, in particular inkjet
printing with pigmented ink, is inkjet printed fabrics are
particularly susceptible to color removal by abrasion and thus have
poor durability. Furthermore, another disadvantage of inkjet
printing, in particular inkjet printing with pigmented ink is that
inkjet printed fabrics do not tolerate washing conditions required
for textiles. The printed colors both fade upon washing and during
the wash the colors can be undesirably transferred to other fabrics
in the wash or to the washing machine parts.
[0022] Still, there is need in the art for improved durability of
inkjet images on textile, especially in cases where the colorant is
pigment.
[0023] It is thus an object of this invention to provide inkjet
printed textiles with improved durability and colorfastness
especially as a result of laundering.
SUMMARY OF THE INVENTION
[0024] It was found that the washfastness and stain rating of an
inkjet printed textile can be improved to a commercially acceptable
level by using a crosslinked polyurethane dispersoid binder in
aqueous inkjet inks. The instant invention is particularly
advantageous for improving the durability of textiles printed with
colorants in inkjet inks, and allows the achievement of
commercially acceptable durability for inkjet ink printed
textiles.
[0025] Thus, in one aspect of the present invention, there is
provided an inkjet ink composition comprising an aqueous vehicle, a
colorant and a crosslinked polyurethane dispersoid, wherein the
colorant is soluble or dispersible in the aqueous vehicle, and
wherein the weight ratio of the crosslinked polyurethane to
colorant is at least about 1.0. The inkjet ink may optionally
comprise other well-known additives or adjuvants as required to
obtain final desired properties.
[0026] The colorant in the inkjet ink preferably ranges from about
0.1 to about 30 wt %, based on the total weight of the ink, and is
preferably a pigment. The crosslinked polyurethane dispersoid is
preferably more than about 1% by weight (solids basis), based on
the total weight of the ink. The amount of crosslinking in the
crosslinked polyurethane is preferably more than about 1%, as
measured by the THF insolubles test discussed in further detail
below.
[0027] In accordance with another aspect of the present invention,
there is provided an inkjet ink set comprising at least three
differently colored inkjet inks, wherein at least one of the inks
is an inkjet ink as set forth above.
[0028] In yet another aspect of the present invention, there is
provided a method for inkjet printing onto a substrate, comprising
the steps of:
[0029] (a) providing an inkjet printer that is responsive to
digital data signals;
[0030] (b) loading the printer with a substrate to be printed;
[0031] (c) loading the printer with an ink as set forth above and
described in further detail below, or an inkjet ink set as set
forth above and described in further detail below; and
[0032] (d) printing onto the substrate using the ink or inkjet ink
set in response to the digital data signals.
[0033] As indicated above, the inks and ink sets in accordance with
the present invention are particularly useful as inkjet inks, more
particularly as inkjet inks for textile printing. Preferred
substrates, therefore, include textiles.
[0034] The printed textile can optionally be subject to a fusing
process after printing. The fusing process requires exposing the
printed textile to a combination of heat and pressure, which has
been found to generally improve the durability of the textile,
particularly when the colorant is a pigment. In particular, the
post treatment combination of heat and pressure has been found to
improve wash fastness and stain rating.
[0035] Another aspect of the present invention is an inkjet printed
textile inkjet printed with a pigmented inkjet ink, said printed
textile having a wash fastness of at least 2.0 and a stain rating
of at least 3.0 (as measured in accordance with AATCC Test Method
61-1996 as the 2A test).
[0036] These and other features and advantages of the present
invention will be more readily understood by those of ordinary
skill in the art from a reading of the following detailed
description. It is to be appreciated that certain features of the
invention which are, for clarity, described above and below in the
context of separate embodiments, may also be provided in
combination in a single embodiment. Conversely, various features of
the invention that are, for brevity, described in the context of a
single embodiment, may also be provided separately or in any
subcombination. In addition, references in the singular may also
include the plural (for example, "a" and "an" may refer to one, or
one or more) unless the context specifically states otherwise.
Further, reference to values stated in ranges include each and
every value within that range.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] The aqueous inks comprise a colorant, a crosslinked
polyurethane dispersoid binder and other ink components, wherein
the colorant is soluble or dispersible in the aqueous vehicle.
[0038] In accordance with the present invention, the term
"polyurethane dispersoid" refers to an aqueous dispersion/emulsion
of a polymer containing urethane groups (e.g., polyurethane), as
those terms are understood by persons of ordinary skill in the art.
The aqueous crosslinked polyurethane dispersoid in accordance with
the present invention comprises a crosslinked polyurethane, and
thus is an aqueous stable polyurethane emulsion or dispersion in
which the polyurethane contains some crosslinking. To distinguish
the polyurethane dispersions/emulsion binders from the other
dispersions and components in the inkjet ink, they are referred to
herein as polyurethane "dispersoid(s)".
[0039] The crosslinked polyurethane dispersoid is combined with the
aqueous vehicle and colorant to produce a stable inkjet ink that
can be used to print textiles. The crosslinked polyurethane
preferably has had substantially all of its crosslinking completed
prior to its addition to the other inkjet ink components. The order
of addition of the ink components can be in any convenient
order.
[0040] Examples of polyurethanes that can be used in the
crosslinked polyurethane dispersoids are described below. As
indicated above, the crosslinking of the polyurethanes is
preferably achieved prior to its addition to the ink system.
[0041] Colorants
[0042] Suitable colorants for the inks of this invention include
soluble colorants such as dyes, and insoluble colorants such as
dispersed pigments (pigment plus dispersing agent) and
self-dispersing pigments.
[0043] Conventional dyes such as anionic, cationic, amphoteric and
non-ionic dyes are useful in this invention. Such dyes are well
known to those of ordinary skill in the art. Anionic dyes are those
dyes that, in aqueous solution, yield colored anions. Cationic dyes
are those dyes that, in aqueous solution, yield colored cations.
Typically anionic dyes contain carboxylic or sulfonic acid groups
as the ionic moiety. Cationic dyes usually contain quaternary
nitrogen groups.
[0044] The types of anionic dyes most useful in this invention are,
for example, Acid, Direct, Food, Mordant and Reactive dyes. Anionic
dyes are selected from the group consisting of nitroso compounds,
nitro compounds, azo compounds, stilbene compounds, triarylmethane
compounds, xanthene compounds, quinoline compounds, thiazole
compounds, azine compounds, oxazine compounds, thiazine compounds,
aminoketone compounds, anthraquinone compounds, indigoid compounds
and phthalocyanine compounds.
[0045] The types of cationic dyes that are most useful in this
invention include mainly the basic dyes and some of the mordant
dyes that are designed to bind acidic sites on a substrate, such as
fibers. Useful types of such dyes include the azo compounds,
diphenylmethane compounds, triarylmethanes, xanthene compounds,
acridine compounds, quinoline compounds, methine or polymethine
compounds, thiazole compounds, indamine or indophenyl compounds,
azine compounds, oxazine compounds, and thiazine compounds, among
others, all of which are well known to those skilled in the
art.
[0046] Useful dyes include (cyan) Acid Blue 9 and Direct Blue 199;
(magenta) Acid Red 52, Reactive Red 180, Acid Red 37, CI Reactive
Red 23; and (yellow) Direct Yellow 86, Direct Yellow 132 and Acid
Yellow 23.
[0047] Pigments suitable for used in the present invention are
those generally well-known in the art for aqueous inkjet inks.
Traditionally, pigments are stabilized by dispersing agents, such
as polymeric dispersants or surfactants, to produce a stable
dispersion of the pigment in the vehicle. More recently though,
so-called "self-dispersible" or "self-dispersing" pigments
(hereafter "SDP") have been developed. As the name would imply,
SDPs are dispersible in water without dispersants. Dispersed dyes
are also considered pigments as they are insoluble in the aqueous
inks used herein.
[0048] Pigments that are stabilized by added dispersing agents may
be prepared by methods known in the art. It is generally desirable
to make the stabilized pigment in a concentrated form. The
stabilized pigment is first prepared by premixing the selected
pigment(s) and polymeric dispersant(s) in an aqueous carrier medium
(such as water and, optionally, a water-miscible solvent), and then
dispersing or deflocculating the pigment. The dispersing step may
be accomplished in a 2-roll mill, media mill, a horizontal mini
mill, a ball mill, an attritor, or by passing the mixture through a
plurality of nozzles within a liquid jet interaction chamber at a
liquid pressure of at least 5,000 psi to produce a uniform
dispersion of the pigment particles in the aqueous carrier medium
(microfluidizer). Alternatively, the concentrates may be prepared
by dry milling the polymeric dispersant and the pigment under
pressure. The media for the media mill is chosen from commonly
available media, including zirconia, YTZ, and nylon. These various
dispersion processes are in a general sense well known in the art,
as exemplified by U.S. Pat. Nos. 5,022,592, 5,026,427, 5,310,778,
5,891,231, 5,679,138, 5,976,232 and US20030089277. The disclosure
of each of these publications is incorporated by reference herein
for all purposes as if fully set forth. Preferred are 2-roll mill,
media mill, and by passing the mixture through a plurality of
nozzles within a liquid jet interaction chamber at a liquid
pressure of at least 5,000 psi.
[0049] After the milling process is complete the pigment
concentrate may be "let down" into an aqueous system. "Let down"
refers to the dilution of the concentrate with mixing or
dispersing, the intensity of the mixing/dispersing normally being
determined by trial and error using routine methodology, and often
being dependent on the combination of the polymeric dispersant,
solvent and pigment.
[0050] The dispersant used to stabilize the pigment is preferably a
polymeric dispersant. Either structured or random polymers may be
used, although structured polymers are preferred for use as
dispersants for reasons well known in the art. The term "structured
polymer" means polymers having a block, branched or graft
structure. Examples of structured polymers include AB or BAB block
copolymers such as disclosed in U.S. Pat. No. 5,085,698; ABC block
copolymers such as disclosed in EP-A-0556649; and graft polymers
such as disclosed in U.S. Pat. No. 5,231,131. Other polymeric
dispersants that can be used are described, for example, in U.S.
Pat. Nos. 6,117,921, 6,262,152, 6,306,994 and 6,433,117. The
disclosure of each of these publications is incorporated herein by
reference for all purposes as if fully set forth.
[0051] Polymer dispersants suitable for use in the present
invention generally comprise both hydrophobic and hydrophilic
monomers. Some examples of hydrophobic monomers used in random
polymers are methyl methacrylate, n-butyl methacrylate,
2-ethylhexyl methacrylate, benzyl methacrylate, 2-phenylethyl
methacrylate and the corresponding acrylates. Examples of
hydrophilic monomers are methacrylic acid, acrylic acid,
dimethylaminoethyl(meth)acrylate and salts thereof. Also quaternary
salts of dimethylaminoethyl(meth)acrylate may be employed.
[0052] A wide variety of organic and inorganic pigments, alone or
in combination, may be selected to make the ink. The term "pigment"
as used herein means an insoluble colorant. The pigment particles
are sufficiently small to permit free flow of the ink through the
inkjet printing device, especially at the ejecting nozzles that
usually have a diameter ranging from about 10 micron to about 50
micron. The particle size also has an influence on the pigment
dispersion stability, which is critical throughout the life of the
ink. Brownian motion of minute particles will help prevent the
particles from flocculation. It is also desirable to use small
particles for maximum color strength and gloss. The range of useful
particle size is typically about 0.005 micron to about 15 micron.
Preferably, the pigment particle size should range from about 0.005
to about 5 micron and, most preferably, from about 0.005 to about 1
micron. The average particle size as measured by dynamic light
scattering is preferably less than about 500 nm, more preferably
less than about 300 nm.
[0053] The selected pigment(s) may be used in dry or wet form. For
example, pigments are usually manufactured in aqueous media and the
resulting pigment is obtained as water-wet presscake. In presscake
form, the pigment is not agglomerated to the extent that it is in
dry form. Thus, pigments in water-wet presscake form do not require
as much deflocculation in the process of preparing the inks as
pigments in dry form. Representative commercial dry pigments are
listed in previously incorporated U.S. Pat. No. 5,085,698.
[0054] In the case of organic pigments, the ink may contain up to
about 30%, preferably about 0.1 to about 25%, and more preferably
about 0.25 to about 10%, pigment by weight based on the total ink
weight. If an inorganic pigment is selected, the ink will tend to
contain higher weight percentages of pigment than with comparable
inks employing organic pigment, and may be as high as about 75% in
some cases, since inorganic pigments generally have higher specific
gravities than organic pigments.
[0055] Self-dispersed pigments (SDPs) can be use with the
crosslinked polyurethane dispersoids and are often advantageous
over traditional dispersant-stabilized pigments from the standpoint
of greater stability and lower viscosity at the same pigment
loading. This can provide greater formulation latitude in final
ink.
[0056] SDPs, and particularly self-dispersing carbon black
pigments, are disclosed in, for example, U.S. Pat. Nos. 2,439,442,
3,023,118, 3,279,935 and 3,347,632. Additional disclosures of SDPs,
methods of making SDPs and/or aqueous inkjet inks formulated with
SDP's can be found in, for example, U.S. Pat. Nos. 5,554,739,
5,571,311, 5,609,671, 5,672,198, 5,698,016, 5,707,432, 5,718,746,
5,747,562, 5,749,950, 5,803,959, 5,837,045, 5,846,307, 5,851,280,
5,861,447, 5,885,335, 5,895,522, 5,922,118, 5,928,419, 5,976,233,
6,057,384, 6,099,632, 6,123,759, 6,153,001, 6,221,141, 6,221,142,
6,221,143, 6,281,267, 6,329,446, US2001/0035110, EP-A-1114851,
EP-A-1158030, WO01/10963, WO01/25340 and WO01/94476. The
disclosures of all of the above-identified publications are
incorporated by reference herein for all purposes as if fully set
forth.
[0057] Polyurethane Dispersoid Binders (PUDs)
[0058] As indicated above, a crosslinked polyurethane dispersoid
refers to an aqueous dispersion of a polymer containing urethane
groups and crosslinking, as those terms are understood by persons
of ordinary skill in the art. These polymers may also incorporate
hydrophilic functionality to the extent required to maintain a
stable dispersion of the polymer in water and, more preferably, the
aqueous vehicle. The main advantage of incorporating hydrophilic
functionality into the polymer is that dispersion can be performed
with minimal energy so that the dispersing processes do not require
strong shear forces, resulting in finer particle size, better
dispersion stability, and reduced water sensitivity of the polymers
obtained after evaporation of the water. These polymers may also
incorporate ionic and nonionic functionality to the extent required
to maintain a stable dispersion of the polymer in water.
Alternatively, these polymers can be prepared by emulsification of
hydrophobic polyurethanes in water with the aid of suitable
external emulsifiers, surfactants and the like, and/or utilizing
strong shear forces to form an oil-in-water dispersion.
[0059] In general, the stability of the crosslinked polyurethane in
the aqueous vehicle is achieved by incorporating anionic, cationic
and/or non-ionic components in the polyurethane polymer, which
facilitates stabilizing the crosslinked polyurethane in aqueous
systems. External emulsifiers may also be added to stabilize the
polyurethane. Combinations of incorporated anionic, cationic and/or
non-ionic components, and/or external emulsifiers can also be
used.
[0060] Examples of suitable polyurethanes are those in which the
polymer is predominantly stabilized in the dispersion through
incorporated anionic functionality, and an example of this is
anionic functionality such as neutralized acid groups ("anionically
stabilized polyurethane dispersoid"). Further details are provided
below. Further examples of hydrophilic functionalization are
cationic and nonionic functionality.
[0061] Suitable aqueous polyurethane dispersoids are typically
prepared by multi-step synthetic processes in which an NCO
terminated prepolymer is formed, this prepolymer is added to water
or water is added to the prepolymer forming a polymer dispersed in
water (aqueous dispersion) and subsequently chain extended in the
aqueous phase. The prepolymer can be formed by a single or
multi-step process. Chain extension, if used, can also be a single
or multi-step process. The important crosslinking can occur as part
of these single or multi-step processes.
[0062] After the polyurethane dispersoid is prepared it is included
with the other ink components to produce the inkjet ink. The
details of the preparation of the ink are familiar to those skilled
in the art.
[0063] It is preferred that the crosslinking for the polyurethane
is substantially completed prior to its addition to the ink
formulation. Other uses of polyurethanes in inkjet system can
require that there is a component in the polyurethane which
undergoes crosslink at the time of the ink formulation, or more
likely at the time of the printing, or post treatment of the
printed material. Alternatively, a crosslinking species can be
added to affect the crosslinking at the ink formulation time or
later. Each of these processes can be described as a
post-crosslinking system,
[0064] As indicated above, the polyurethane dispersoid is typically
prepared by a multiple step process. Typically, in the first stage
of prepolymer formation, a diisocyanate is reacted with a compound,
polymer, or mixtures of compound, mixture of polymers or a mixture
thereof, each containing two NCO-reactive groups. An additional
compound or compounds, all containing .gtoreq.2 NCO-reactive groups
as well as a stabilizing ionic functionality, is also used to form
an intermediate polymer. This intermediate polymer or pre-polymer
can be terminated with either an NCO-group or a NCO-reactive group.
The terminal groups are defined by the molar ratio of NCO to
NCO-reactive groups in the prepolymer stage. Typically, the
pre-polymer is an NCO-terminated material that is achieved by using
a molar excess of NCO. Thus, the molar ratio of diisocyanate to
compounds containing two isocyanate-reactive groups is at least
about 1.1:1.0, preferably about 1.20:1.0 to about 5.0:1.0, and more
preferably about 1.20:1.0 to about 2.5:1.0. In general, the ratios
are achieved by preparing, in a first stage, an NCO-terminated
intermediate by reacting one of the NCO-reactive compounds, having
at least 2 NCO reactive groups, with all or part of the
diisocyanate. This is followed, in sequence, by additions of other
NCO-reactive compounds, if desired. When all reactions are complete
the group, NCO and/or NCO-reactive groups will be found at the
termini of the pre-polymer. These components are reacted in amounts
sufficient to provide a molar ratio such that the overall
equivalent ratio of NCO groups to NCO-reactive groups is
achieved.
[0065] Suitable diisocyanates are those that contain either
aromatic, cycloaliphatic or aliphatic groups bound to the
isocyanate groups. Mixtures of these compounds may also be used.
The preferred is a prepolymer that has isocyanates bound to a
cycloaliphatic or aliphatic moieties. If aromatic diisocyanates are
used, cycloaliphatic or aliphatic isocyanates are preferably
present as well.
[0066] Examples of suitable diisocyanates include cyclohexane-1,3-
and -1,4-diisocyanate;
1-isocyanato-3-isocyanatomethyl-3,5,5-trimethyl-cycloh- exane
(isophorone diisocyanate or IPDI);
bis-(4-isocyanatocyclohexyl)-meth- ane; 1,3- and
1,4-bis-(isocyanatomethyl)-cyclohexane;
1-isocyanato-2-isocyanatomethyl cyclopentane;;
2,4'-diisocyanato-dicycloh- exyl methane;
bis-(4-isocyanato-3-methyl-cyclohexyl)-methane,
alpha,alpha,alpha',alpha'-tetramethyl-1,3- and/or -1,4-xylylene
diisocyanate; 1-isocyanato-1-methyl-4(3)-isocyanatomethyl
cyclohexane; and 2,4- and/or 2,6-hexahydrotoluylene
diisocyanate.
[0067] Additional diisocyanates may be linear or branched and
contain 4 to 12 carbon atoms, preferably 4 to 9 carbon which
include 1,4-tetramethylene diisocyanate; 1,6-hexamethylene
diisocyanate; 2,2,4-trimethyl-1,6-hexamethylene diisocyanate; and
1,12-dodecamethylene diisocyanate. 1,6-hexamethylene diisocyanate
and isophorone diisocyanate are examples of diisocyanates effective
for the crosslinked polyurethanes
[0068] Examples of non-ionic dispersing groups include, for
example, a non-ionic dispersing segment present within the
polyurethane which is solvent-soluble and that promotes dispersion
of the polyurethane within a chosen solvent. When the chosen
solvent comprises water, for example, a non-ionic dispersing
segment can be a hydrophilic dispersing segment such as an alkylene
oxide or polyoxyalkylene oxide segment, e.g.,
--((CH.sub.2).sub.nO).sub.m--, wherein n can preferably be from 2
to 4, and m can be from about 1 to 400, preferably from about 5 to
200.
[0069] Isocyanate-reactive compounds containing ionic groups, for
example anionic and cationic groups, can be chemically incorporated
into the polyurethane to provide hydrophilicity and enable the
polyurethane to be dispersed in an aqueous medium.
[0070] Examples of ionic dispersing groups include carboxylate
groups (--COOM), phosphate groups (--OPO.sub.3 M.sub.2),
phosphonate groups (--PO.sub.3 M.sub.2), sulfonate groups
(--SO.sub.3 M), quaternary ammonium groups (--NR.sub.3 Y, wherein Y
is a monovalent anion such as chlorine or hydroxyl), or any other
effective ionic group. M is a cation such as a monovalent metal ion
(e.g., Na.sup.+, K.sup.+, Li.sup.+, etc.), H.sup.+, NR.sub.4.sup.+,
and each R can be independently an alkyl, aralkyl, aryl, or
hydrogen. These ionic dispersing groups are typically located
pendant from the polyurethane backbone.
[0071] In the case of anionic group substitution, the groups can be
carboxylic acid groups, carboxylate groups, sulphonic acid groups,
sulphonate groups, phosphoric acid groups and phosphonate groups,
The acid salts are formed by neutralizing the corresponding acid
groups either prior to, during or after formation of the NCO
prepolymer, preferably after formation of the NCO prepolymer.
[0072] Suitable compounds for incorporating carboxyl groups are
described in U.S. Pat. Nos. 3,479,310, 4,108,814 and 4,408,008, the
disclosures of which are incorporated by reference herein for all
purposes as if fully set forth. The neutralizing agents for
converting the carboxylic acid groups to carboxylate salt groups
are described in the preceding incorporated publications, and are
also discussed hereinafter. Within the context of this invention,
the term "neutralizing agents" is meant to embrace all types of
agents that are useful for converting carboxylic acid groups to the
more hydrophilic carboxylate salt groups. In like manner, sulphonic
acid groups, sulphonate groups, phosphoric acid groups, and
phosphonate groups can be neutralized with similar compounds to
their more hydrophilic salt form.
[0073] Examples of carboxylic group-containing compounds are the
hydroxy-carboxylic acids corresponding to the formula
(HO).sub.xQ(COOH).sub.y wherein Q represents a straight or
branched, hydrocarbon radical containing 1 to 12 carbon atoms, x is
1 or 2 (preferably 2), and y is 1 to 3 (preferably 1 or 2).
[0074] Examples of these hydroxy-carboxylic acids include citric
acid, tartaric acid and hydroxypivalic acid.
[0075] Especially preferred acids are those of the above-mentioned
formula wherein x=2 and y=1. These dihydroxy alkanoic acids are
described in U.S. Pat. No. 3,412,054, the disclosure of which is
incorporated by reference herein for all purposes as if fully set
forth. Especially preferred dihydroxy alkanoic acids are the
alpha,alpha-dimethylol alkanoic acids represented by the structural
formula: 1
[0076] wherein Q' is hydrogen or an alkyl group containing 1 to 8
carbon atoms. The most preferred compound is alpha,alpha-dimethylol
propionic acid, i.e., wherein Q' is methyl in the above
formula.
[0077] When the ionic stabilizing groups are acids, the acid groups
are incorporated in an amount sufficient to provide an acid group
content, known by those skilled in the art as acid number (mg KOH
per gram solid polymer), of at least about 5, preferably at least
about 10 milligrams KOH per 1.0 gram of polyurethane. The upper
limit for the acid number (AN) is about 50, preferably about
40.
[0078] Suitable polyols containing at least two NCO reactive
groups, which may be reacted to prepare the prepolymer, are those
having a molecular weight of about 60 to about 6000. Of these, the
polymeric polyols are best defined by the number average molecular
weight, and can range from about 200 to about 6000, preferably
about 800 to about 3000, and more preferably about 1000 to about
2500. The molecular weights are determined by hydroxyl group
analysis (OH number). Examples of these high molecular weight
compounds include polyester, polyether, polycarbonates,
polyacetals, poly(meth)acrylates, polyester amides, polythioethers
or mixed polymers such as a polyester-polycarbonate where both
ester and carbonate linkages are found in the same polymer. A
combination of these polymers can also be used. For examples, a
polyester polyol and a poly(meth)acrylate polyol may be used in the
same polyurethane synthesis.
[0079] Similar NCO reactive materials can be used as described for
hydroxy containing compounds and polymers, but which contain other
NCO reactive groups. Examples would be dithiols, diamines,
thioamines and even hydroxythiols and hydroxylamines. These can
either be compounds or polymers with the molecular weights or
number average molecular weights as described for the polyols.
[0080] Suitable polyester diols include reaction products of
polyhydric, preferably dihydric alcohols to which trihydric
alcohols may optionally be added, and polybasic (preferably
dibasic) carboxylic acids. Instead of these polycarboxylic acids,
the corresponding carboxylic acid anhydrides or polycarboxylic acid
esters of lower alcohols or mixtures thereof may be used for
preparing the polyesters.
[0081] The polycarboxylic acids may be aliphatic, cycloaliphatic,
aromatic and/or heterocyclic or mixtures thereof and they may be
substituted, for example, by halogen atoms, and/or unsaturated. The
following are mentioned as examples: succinic acid; adipic acid;
suberic acid; azelaic acid; sebacic acid; 1,12-dodecyldioic acid;
phthalic acid; isophthalic acid; trimellitic acid; phthalic acid
anhydride; tetrahydrophthalic acid anhydride; hexahydrophthalic
acid anhydride; tetrachlorophthalic acid anhydride; endomethylene
tetrahydrophthalic acid anhydride; glutaric acid anhydride; maleic
acid; maleic acid anhydride; fumaric acid; dimeric and trimeric
fatty acids such as oleic acid, which may be mixed with monomeric
fatty acids; dimethyl terephthalates and bis-glycol
terephthalate.
[0082] Suitable polyhydric alcohols include, e.g., ethylene glycol;
propylene glycol-(1,2) and -(1,3); butylene glycol-(1,4) and
-(1,3); hexanediol-(1,6); octanediol-(1,8); neopentyl glycol;
cyclohexanedimethanol (1,4-bis-hydroxymethyl-cyclohexane);
2-methyl-1,3-propanediol; 2,2,4-trimethyl-1,3-pentanediol;
triethylene glycol; tetraethylene glycol; polyethylene glycol;
dipropylene glycol; polypropylene glycol; dibutylene glycol and
polybutylene glycol, glycerine, trimethylol-propane, polyether
diols such as polyethylene glycol, polypropylene glycol,
polybutylene glycol or mixed monomer polyether glycols. The
polyesters may also contain a portion of carboxyl end groups.
Polyesters of lactones, for example, epsilon-caprolactone, or
hydroxycarboxylic acids, for example, omega-hydroxycaproic acid,
may also be used.
[0083] Polycarbonates containing hydroxyl groups include those
known, per se, such as the products obtained from the reaction of
diols such as propanediol-(1,3), butanediol-(1,4) and/or
hexanediol-(1,6), diethylene glycol, triethylene glycol or
tetraethylene glycol, higher polyether diols with phosgene,
diarylcarbonates such as diphenylcarbonate, dialkylcarbonates such
as diethylcarbonate or with cyclic carbonates such as ethylene or
propylene carbonate. Also suitable are polyester carbonates
obtained from the above-mentioned polyesters or polylactones with
phosgene, diaryl carbonates, dialkyl carbonates or cyclic
carbonates.
[0084] Suitable polyether polyols are obtained in a known manner by
the reaction of starting compounds that contain reactive hydrogen
atoms with alkylene oxides such as ethylene oxide, propylene oxide,
butylene oxide, styrene oxide, tetrahydrofuran, epichlorohydrin or
mixtures of these. It is preferred that the polyethers do not
contain more than about 10% by weight of ethylene oxide units. Most
preferably, polyethers obtained without the addition of ethylene
oxide are used. Suitable starting compounds containing reactive
hydrogen atoms include the polyhydric alcohols set forth for
preparing the polyester polyols and, in addition, water, methanol,
ethanol, 1,2,6-hexane triol, 1,2,4-butane triol, trimethylol
ethane, pentaerythritol, mannitol, sorbitol, methyl glycoside,
sucrose, phenol, isononyl phenol, resorcinol, hydroquinone, 1,1,1-
and 1,1,2-tris-(hydroxylphenyl)-ethane, dimethylolpropionic acid or
dimethylolbutanoic acid.
[0085] Polyethers that have been obtained by the reaction of
starting compounds containing amine compounds can also be used.
Examples of these polyethers as well as suitable polyhydroxy
polyacetals, polyhydroxy polyacrylates, polyhydroxy polyester
amides, polyhydroxy polyamides and polyhydroxy polythioethers, are
disclosed in U.S. Pat. No. 4,701,480 (the disclosure of which is
incorporated by reference herein for all purposes as if fully set
forth).
[0086] Poly(meth)acrylates containing hydroxyl groups include those
common in the art of addition polymerization such as cationic,
anionic and radical polymerization and the like. Examples are
alpha-omega diols. An example of these type of diols are those
which are prepared by a "living" or "control" or chain transfer
polymerization processes which enables the placement of one
hydroxyl group at or near the termini of the polymer. U.S. Pat. No.
6,248,839 and U.S. Pat. No. 5,990,245 (the disclosures of which are
incorporated by reference herein for all purposes as if fully set
forth) have examples of protocol for making terminal diols. Other
di-NCO reactive poly(meth)acrylate terminal polymers can be used.
An example would be end groups other than hydroxyl such as amino or
thiol, and may also include mixed end groups with hydroxyl.
[0087] The high molecular weight polyols are generally present in
the polyurethanes in an amount of at least about 5%, preferably at
least about 10% by weight, based on the weight of the polyurethane.
The maximum amount of these polyols is generally about 85%, and
preferably about 75% by weight, based on the weight of the
polyurethane.
[0088] Other optional compounds for preparing the NCO prepolymer
include low molecular weight, at least difunctional NCO-reactive
compounds having an average molecular weight of up to about 400.
Examples include the dihydric and higher functionality alcohols,
which have previously been described for the preparation of the
polyester polyols and polyether polyols.
[0089] In addition to the above-mentioned components, which are
preferably difunctional in the isocyanate polyaddition reaction,
mono-functional and even small portions of trifunctional and higher
functional components generally known in polyurethane chemistry,
such as trimethylolpropane or 4-isocyanantomethyl-1,8-octamethylene
diisocyanate, may be used in cases in which branching of the NCO
prepolymer or polyurethane is desired. However, the NCO prepolymers
should be substantially linear and this may be achieved by
maintaining the average functionality of the prepolymer starting
components at or below 2:1.
[0090] Other optional compounds include NCO-reactive compounds
containing branched and/or terminal, hydrophilic and/or hydrophobic
units. These units include non-ionic hydrophilic materials such as
polyethylene oxides or copolymers with other oxide, and hydrophilic
polyoxazolines. The content of hydrophilic units (when present) may
be up to about 10%, preferably up to about 8% and most preferably
about 2 to about 6%, by weight, based on the weight of the
polyurethane. In addition, up to about 75% of the allowable,
chemically incorporated, hydrophilic units may be replaced by known
nonionic, external emulsifiers. Examples of these are the alkaryl
type polyoxyethylene, nonyl phenyl ether or polyoxyethylene octyl
phenyl ether; those of the alkyl ether type such as polyoxyethylene
lauryl ether or polyoxyethylene oleyl ether; those of the alkyl
ester type such as polyoxyethylene laurate, polyoxyethylene oleate
or polyoxyethylene stearate; and those of the polyoxyethylene
benzylated phenyl ether type.
[0091] The isocyanate-reactive compounds for incorporating branched
and/or terminal, hydrophilic and/or hydrophobic units may contain
either one or two isocyanate-reactive groups, preferably hydroxy
groups. Examples of these compounds are disclosed in U.S. Pat. Nos.
3,905,929, 3,920,598 and 4,190,566 (the disclosures of which are
incorporated by reference herein for all purposes as if fully set
forth). Preferred hydrophilic components are the monohydroxy
polyethers or monohydroxyl oxazolines. These hydrophilic compoents
may be produced as described in the preceding patents by
alkoxylating a monofunctional starter, such as methanol or n-
butanol, using ethylene oxide and optionally another alkylene
oxide, such as propylene oxide or in the case of oxazolines,
methylox-zoline.
[0092] Other optional compounds include isocyanate-reactive
compounds containing selfcondensing moieties. The content of these
compounds are dependent upon the desired level of self-condensation
necessary to provide the desirable resin properties.
3-amino-1-triethoxysilyl-propane is an example of a compound that
will react with isocyanates through the amino group and yet
self-condense through the silyl group when inverted into water.
[0093] Other optional compounds include isocyanate-reactive
compounds containing non-condensable silanes and/or fluorocarbons
with isocyanate reactive groups, which can be used in place of or
in conjunction with the isocyanate-reactive compounds. U.S. Pat.
No. 5,760,123 and U.S. Pat. No. 6,046,295 (the disclosures of which
are incorporated by reference herein for all purposes as if fully
set forth) list examples of methods for use of these optional
silane/fluoro-containing compounds.
[0094] Process conditions for preparing the NCO containing
prepolymers have been discussed in the publications previously
noted. The finished NCO containing prepolymer should have a
isocyanate content of about 1 to about 20%, preferably about 1 to
about 10% by weight, based on the weight of prepolymer solids.
[0095] Mixtures of compounds and/or polymers having mixed NCO
reactive groups are also possible.
[0096] The polyurethanes are typical prepared by chain extending
these NCO containing prepolymers. Chain extenders are polyamine
chain extenders, which can optionally be partially or wholly
blocked as disclosed in U.S. Pat. No. 4,269,748 and U.S. Pat. No.
4,829,122 (the disclosures of which are incorporated by reference
herein for all purposes as if fully set forth). These publications
disclose the preparation of aqueous polyurethane dispersoids by
mixing NCO-containing prepolymers with at least partially blocked,
diamine or hydrazine chain extenders in the absence of water and
then adding the mixture to water. Upon contact with water the
blocking agent is released and the resulting unblocked polyamine
reacts with the NCO containing prepolymer to form the
polyurethane.
[0097] Suitable blocked amines and hydrazines include the reaction
products of polyamines with ketones and aldehydes to form ketimines
and aldimines, and the reaction of hydrazine with ketones and
aldehydes to form ketazines, aldazines, ketone hydrazones and
aldehyde hydrazones. The at least partially blocked polyamines
contain at most one primary or secondary amino group and at least
one blocked primary or secondary amino group which releases a free
primary or secondary amino group in the presence of water.
[0098] Suitable polyamines for preparing the at least partially
blocked polyamines have an average functionality, i.e., the number
of amine nitrogens per molecule, of 2 to 6, preferably 2 to 4 and
more preferably 2 to 3. The desired functionalities can be obtained
by using mixtures of polyamines containing primary or secondary
amino groups. The polyamines are generally aromatic, aliphatic or
alicyclic amines and contain between 1 to 30, preferably 2 to 15
and more preferably 2 to 10 carbon atoms. These polyamines may
contain additional substituents provided that they are not as
reactive with isocyanate groups as the primary or secondary amines.
These same polyamines can be partially or wholly blocked
polyamines.
[0099] A suitable method of chain extension is to add polyamine to
the NCO-prepolymer before, during or after the pre-polymer
inversion into water. Optionally, the chain extension can occur
after pre-polymer inversion. The polyamines include
1-amino-3-aminomethyl-3,5,5-trimethylcy- clohexane (isophorone
diamine or IPDA), bis-(4-amino-cyclohexyl)-methane,
bis-(4-amino-3-methylcyclohexyl)-methane, 1,6-diaminohexane,
hydrazine, ethylene diamine, diethylene triamine, triethylene
tetramine, tetraethylene pentamine and pentaethylene hexamine.
[0100] In some cases, chain termination may be desirable. This
requires the addition, in most cases, of a mono-NCO reactive
material such as a mono-amine or mono-alcohol. The materials can be
added before, during or after inversion of the pre-polymer.
Poly-NCO reactive materials can be used where one of the
NCO-reactive groups reacts substantially faster than the others.
Examples would be ethanol amine and diethanol amine. The amine
group will react much faster with the NCO group than the
alcohol.
[0101] Suitable chain terminators would be amines or alcohols
having an average functionality per molecule of 1, i.e., the number
of primary or secondary amine nitrogens or alcohol oxygens would
average 1 per molecule. The desired functionalities can be obtained
by using primary or secondary amino groups. The amines or alcohols
are generally aromatic, aliphatic or alicyclic and contain between
1 to 30, preferably 2 to 15 and more preferably 2 to 10 carbon
atoms. These may contain additional substituents provided that they
are not as reactive with isocyanate groups as the amine or alcohol
groups.
[0102] Chain terminators and chain extenders can be used together,
either as mixtures or as sequential additions to the
NCO-prepolymer.
[0103] The amount of chain extender and/or chain terminator to be
used in accordance with the present invention is dependent upon the
number of isocyanate groups in the prepolymer. Preferably, the
ratio of isocyanate groups of the prepolymer to isocyanate-reactive
groups of the chain extender/terminator is between about 1.0:0.6
and about 1.0:1.1, more preferably between about 1.0:0.7 and about
1.0:1.1, on an equivalent basis. Any isocyanate groups that are not
chain extended/terminated with an amine or alcohol will react with
water, which functions as a chain extender.
[0104] Chain extension can take place prior to addition of water in
the process, but typically takes place by combining the NCO
containing prepolymer, chain extender, water and other optional
components under agitation.
[0105] In order to have a stable dispersion, a sufficient amount of
the ionic groups (if present) must be neutralized so that, when
combined with the optional hydrophilic ethylene oxide and other
alkenyl oxide units and optional external emulsifiers, the
resulting polyurethane will remain stably dispersed in the aqueous
medium. Generally, at least about 70%, preferably at least about
80%, of the acid groups are neutralized to the corresponding
carboxylate salt groups. Alternatively, cationic groups in the
polyurethane can be quaternary ammonium groups (--NR.sub.3Y,
wherein Y is a monovalent anion such as chlorine or hydroxyl).
[0106] Suitable neutralizing agents for converting the acid groups
to salt groups include tertiary amines, alkali metal cations and
ammonia. Examples of these neutralizing agents are disclosed in
previously incorporated U.S. Pat. No. 4,701,480, as well as U.S.
Pat. No. 4,501,852 (the disclosure of which is incorporated by
reference herein for all purposes as if fully set forth). Preferred
neutralizing agents are the trialkyl-substituted tertiary amines,
such as triethyl amine, tripropyl amine, dimethylcyclohexyl amine,
and dimethylethyl amine. Substituted amines are also useful
neutralizing groups such as diethyl ethanol amine or diethanol
methyl amine.
[0107] Neutralization may take place at any point in the process.
Typical procedures include at least some neutralization of the
prepolymer, which is then chain extended/terminated in water in the
presence of additional neutralizing agent.
[0108] The final product is a stable aqueous dispersoid of
polyurethane particles having a solids content of up to about 60%
by weight, preferably about 15 to about 60% by weight and most
preferably about 30 to about 40% by weight. However, it is always
possible to dilute the dispersions to any minimum solids content
desired.
[0109] The means to achieve the crosslinking of the polyurethane
generally relies on at least one component of the polyurethane
(starting material and/or intermediate) having 3 or more functional
reaction sites. Reaction of each of the 3 (or more) reaction sites
will produce a crosslinked polyurethane (3-dimensional matrix).
When only two reactive sites are available on each reactive
components, only linear (albeit possibly high molecular weight)
polyurethanes can be produced. Examples of crosslinking techniques
include but are not limited to the following:
[0110] the isocyanate-reactive moiety has at least 3 reactive
groups, for example polyfunctional amines or polyol;
[0111] the isocyanate has at least 3 isocyanate groups;
[0112] the prepolymer chain has at least 3 reactive sites that can
react via reactions other than the isocyanate reaction, for example
with amino trialkoxysilanes;
[0113] addition of a reactive component with at least 3 reactive
sites to the polyurethane prior to its use in the inkjet ink
preparations, for example tri-functional epoxy crosslinkers;
[0114] addition of a water-dispersible crosslinker with oxazoline
functionality;
[0115] synthesis of a polyurethane with carbonyl functionality,
followed by addition of a dihydrazide compound;
[0116] and any combination of the these crosslinking methods and
other crosslinking means known to those of ordinary skill in the
relevant art.
[0117] Also, it is understood that these crosslinking components
may only be a (small) fraction of the total reactive functionality
added to the polyurethane. For example, when polyfunctional amines
are added, mono- and difunctional amines may also be present for
reaction with the isocyanates. The polyfunctional amine may be a
minor portion of the amines.
[0118] The crosslinking preferably occurs during the preparation of
the polyurethane. A preferred time for the crosslinking in the
polyurethane reaction sequence would be at or after the time of the
inversion step. That is, crosslinking preferably occurs during the
addition of water to the polyurethane preparation mixture or
shortly thereafter. The inversion is that point where sufficient
water is added such that the polyurethane is converted to its
stable dispersed aqueous form. Most preferred is that the
crosslinking occurs after the inversion. Furthermore, substantially
all of the crosslinking of the polyurethane is preferably complete
prior to its incorporation into the ink formulation.
[0119] Alternatively, the crosslinking can occur during the initial
formation of the urethane bonds when the isocyanates or
isocyanate-reactive groups have 3 or more groups capable of
reacting. If the crosslinking is done at this early stage, the
extent of crosslinking must not lead to gel formation. Too much
crosslinking at this stage will prevent the formation of a stable
polyurethane dispersion.
[0120] The amount of crosslinking of the polyurethane to achieve
the desired inkjet ink for textiles can vary over a broad range.
While not being bound to theory, the amount of crosslinking is a
function of the polyurethane composition, the whole sequence of
reaction conditions utilized to form the polyurethane and other
factors known to those of ordinary skill in the art. The extent of
crosslinking, the inkjet ink formulation, the colorant, other inks
in the inkjet set, the textile, the post treatment exposure to heat
and/or pressure, and the printing technique for the textile, all
contribute to the final printed textile performance. For the
printing technique this can include pre and post treatment of the
textile.
[0121] Based on techniques described herein, a person of ordinary
skilled in the art is able to determine, via routine
experimentation, the crosslinking needed for a particularly type of
polyurethane to obtain an effective inkjet ink for textiles.
Furthermore, as indicated above, these inks may also be used for
plain paper, photo paper, transparencies, vinyl and other printable
substrates.
[0122] The amount of crosslinking can be measured by a standard
tetrahydrofuran insolubles test. For the purposes of definition
herein, the tetrahydrofuran (THF) insolubles of the polyurethane
dispersoid is measured by mixing 1 gram of the polyurethane
dispersoid with 30 grams of THF in a pre-weighed centrifuge tube.
After the solution is centrifuged for 2 hours at 17,000 rpm, the
top liquid layer is poured out and the non-dissolved gel in the
bottom is left. The centrifuge tube with the non-dissolved gel is
re-weighed after the tube is put in the oven and dried for 2 hours
at 110.degree. C.
[0123] % THF insolubles of polyurethane=(weight of tube and
non-dissolved gel-weight of tube)/(sample weight*polyurethane solid
%)
[0124] The upper limit of crosslinking is related to the ability to
make a stable aqueous polyurethane dispersion. If a highly
crosslinked polyurethane has adequate ionic or non-ionic
functionality such that it is a stable when inverted into water,
then its level of crosslinking will lead to an improved inkjet ink
for textiles. The emulsion/dispersion stability of the crosslinked
polyurethane can be improved by added dispersants or emulsifiers.
The upper limit of crosslinking as measured by the THF insolubles
test is about 90%. Alternatively the upper limit is about 60%.
[0125] The lower limit of crosslinking in the polyurethane
dispersoid is about 1% or greater, preferably about 4% or greater,
and more preferably about 10% or greater, as measured by the THF
insolubles test.
[0126] An alternative way to achieve an effective amount of
crosslinking in the polyurthane is to choose a polyurethane that
has crosslinkable sites, then crosslink those sites via
self-crosslinking and/or added crosslinking agents. Examples of
self-crosslinking functionality includes, for example, silyl
functionality (self-condensing) available from certain starting
materials as indicated above, as well as combinations of reactive
functionalities incorporated into the polyurethanes, such as
epoxy/hydroxyl, epoxy/acid and isocyanate/hydroxyl. Examples of
polyurethanes and complementary crosslinking agents include: (1) a
polyurethane with isocyanate reactive sites (such as hydroxyl
and/or amine groups) and an isocyanate crosslinking reactant, and
2) a polyurethane with unreacted isocyanate groups and an
isocyanate-reactive crosslinking reactant (containing, for example,
hydroxyl and/or amine groups). The complementary reactant can be
added to the polyurethane, such that crosslinking can be done prior
to its incorporation into an ink formulation. The crosslinking
should preferably be substantially completed prior to the
incorporation of the dispersoid into the ink formulation. This
crosslinked polyurethane preferably has from about 1% to about 90%
crosslinking as measured by the THF insolubles test.
[0127] Combinations of two or more polyurethane crosslinked
dispersoid binders may also be utilized in the formulation of the
ink.
[0128] The crosslinked polyurethane dispersoid can be mixed with
other binders, including latexes, and the like. A non-limiting list
of these binders includes dispersed acrylics, neoprenes, dispersed
nylons, and non-crosslinked polyurethanes dispersions (as defined
herein by the THF insolubles test).
[0129] The term "latex" as used herein refers to a polymer particle
that is dispersed in the vehicle. A latex is sometimes referred to
as an "emulsion polymer". A latex is stabilized to dispersion by
stabilizers which can be part of the polymer itself (internal
stabilizers) or separate species (external stabilizers) such as
emulsifiers.
[0130] Commercially available latexes have a median particle size
in the range of about 0.02 to about 3 microns. For the present
invention, the median particle size should preferably be less than
about 1 micron, more preferably less than about 0.5 microns, and
most preferably in the range of about 0.03 to about 0.3
microns.
[0131] Polymer synthesis for these latexes can be performed under
emulsion polymerization conditions with standard free radical
initiators, chain transfer initiators and surfactants. Chain
transfer agents such as dodecyl mercaptan and sulfur are used to
control the molecular weight, branching, and gel content. Molecular
weight is typically in the range of about 100,000 to over about
1,000,000 Dalton. The percent conversion is also controlled to
limit the gel content.
[0132] Aqueous Vehicle
[0133] "Aqueous vehicle" refers to water or a mixture of water and
at least one water-soluble organic solvent (co-solvent). Selection
of a suitable mixture depends on requirements of the specific
application, such as desired surface tension and viscosity, the
selected colorant, drying time of the ink, and the type of
substrate onto which the ink will be printed. Representative
examples of water-soluble organic solvents that may be selected are
disclosed in previously incorporated U.S. Pat. No. 5,085,698.
[0134] The aqueous inks of the present invention are comprised
primarily of water. Thus, the instant inks comprise at least about
40%, preferably at least about 45%, and more preferably at least
about 50% by weight of water, based on the total weight of the
ink.
[0135] If a mixture of water and a water-soluble solvent is used,
the aqueous vehicle typically will contain about 40% to about 95%
by weight water with the balance (i.e., about 60% to about 5% by
weight) being the water-soluble solvent. Preferred compositions
contain about 65% to about 95% by weight water, based on the total
weight of the aqueous vehicle.
[0136] The amount of aqueous vehicle in the ink is typically in the
range of about 70% to about 99.8%, and preferably about 80% to
about 99.8%, by weight based on total weight of the ink.
[0137] The aqueous vehicle can be made to be fast penetrating
(rapid drying) by including surfactants or penetrating agents such
as glycol ethers and 1,2-alkanediols. Glycol ethers include
ethylene glycol monobutyl ether, diethylene glycol mono-n-propyl
ether, ethylene glycol mono-iso-propyl ether, diethylene glycol
mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene
glycol mono-t-butyl ether, diethylene glycol mono-n-butyl ether,
triethylene glycol mono-n-butyl ether, diethylene glycol
mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol
mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene
glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether,
dipropylene glycol mono-n-butyl ether, dipropylene glycol
mono-n-propyl ether, and dipropylene glycol mono-isopropyl ether.
1,2-alkanediols are preferably 1,2-C.sub.4-6 alkanediols, most
preferably 1,2-hexanediol. Suitable surfactants include ethoxylated
acetylene diols (e.g. Surfynols.RTM. series from Air Products),
ethoxylated primary (e.g. Neodol.RTM. series from Shell) and
secondary (e.g. Tergitol.RTM. series from Union Carbide) alcohols,
Pluronic.RTM. block copolymer surfactants, sulfosuccinates (e.g.
Aerosol.RTM. series from Cytec), organosilicones (e.g. Silwet.RTM.
series from Witco) and fluoro surfactants (e.g. Zonyl.RTM. series
from DuPont).
[0138] The amount of glycol ether(s) and 1,2-alkanediol(s) added
must be properly determined, but is typically in the range of from
about 1 to about 15% by weight and more typically about 2 to about
10% by weight, based on the total weight of the ink.
[0139] Surfactants may be used, typically in the amount of about
0.01 to about 5% and preferably about 0.1 to about 1%, based on the
total weight of the ink.
[0140] In addition, solvents that are not water miscible may be
added to the ink to facilitate the printing the ink which has a
polyurethane dispersoid binder in it. While not being bound by
theory, it is believed that this added non-aqueous solvent assists
in the coalescence of the polyurethane onto the printed substrate,
especially a fabric in the case of textile printing. Examples of
these water-immiscible solvents are propylene carbonate and
dipropylene glycol monomethyl ether.
[0141] Proportion of Main Ingredients
[0142] The pigment levels employed in the textile inks are those
levels which are typically needed to impart the desired color
density to the printed image. Typically, pigment is present at a
level of about 0.1% up to a level of about 30% by weight of the
total weight of ink. Alternatively, the pigment can be about 0.25
to about 25% of the total weight of the ink. Further, the pigment
can be about 0.25 to about 15% of the total weight of the ink.
[0143] The crosslinked polyurethane dispersoid level employed is
dictated by the range of ink properties that can be tolerated.
Generally, polyurethane levels will range up to about 30%, more
particularly from about 1% up to about 25%, and typically about 4%
to about 20%, by weight (polyurethane solids basis) of the total
weight of ink.
[0144] Effective levels of polyurethane are typically those where
the weight ratio of polyurethane (solids) to colorant (pigment) is
at least about 1.0, preferably more than about 1.0, alternatively
more than about 1.33 and even further more than about 1.5. This
weight ratio must be balanced against other ink properties, such as
viscosity, to maintain acceptable jetting performance. The right
balance of properties must be determined for each circumstance,
which can be done by the person of ordinary skill in the art using
routine experimentation.
[0145] Other Ingredients
[0146] The inkjet ink may contain other ingredients as are well
known in the art. For example, anionic, nonionic, cationic or
amphoteric surfactants may be used. In aqueous inks, the
surfactants are typically present in the amount of about 0.01 to
about 5%, and preferably about 0.2 to about 2%, based on the total
weight of the ink.
[0147] Co-solvents, such as those exemplified in U.S. Pat. No.
5,272,201 (incorporated by reference herein for all purposes as if
fully set forth) may be included to improve pluggage inhibition
properties of the ink composition.
[0148] Biocides may be used to inhibit growth of
microorganisms.
[0149] Sequestering agents such as EDTA may also be included to
eliminate deleterious effects of heavy metal impurities.
[0150] Ink Properties
[0151] Jet velocity, separation length of the droplets, drop size
and stream stability are greatly affected by the surface tension
and the viscosity of the ink. Inkjet inks suitable for use with
inkjet printing systems should have a surface tension in the range
of about 20 dyne/cm to about 70 dyne/cm, more preferably about 25
to about 40 dyne/cm at 25.degree. C. Viscosity is preferably in the
range of about 1 cP to about 30 cP, more preferably about 2 to
about 20 cP at 25.degree. C. The ink has physical properties
compatible with a wide range of ejecting conditions, i.e., driving
frequency of the pen and the shape and size of the nozzle.
[0152] The inks should have excellent storage stability for long
periods. Preferably, the instant inks can sustain elevated
temperature in a closed container for extended periods (e.g.
70.degree. C. for 7 days) without substantial increase in viscosity
or particle size.
[0153] Further, the ink should not corrode parts of the inkjet
printing device it comes in contact with, and it should be
essentially odorless and non-toxic.
[0154] Inks of the instant invention can achieve the beneficial
durable properties of wash-fastness.
[0155] Ink Sets
[0156] The ink sets in accordance with the present invention
preferably comprise at least three differently colored inks (such
as CMY), and preferably at least four differently colored inks
(such as CMYK), wherein at least one of the inks is an aqueous
inkjet ink comprising an aqueous vehicle, a colorant and a
crosslinked polyurethane dispersoid, wherein the colorant is
soluble or dispersible in the aqueous vehicle, and wherein the
weight ratio of polyurethane dispersoid to colorant is at least
about 1.0, as set forth above.
[0157] The other inks of the ink set are preferably also aqueous
inks, and may contain dyes, pigments or combinations thereof as the
colorant. Such other inks are, in a general sense, well known to
those of ordinary skill in the art.
[0158] In one preferred embodiment, the ink set comprises three
differently colored inks as follows:
[0159] (a) a first colored ink comprising a first aqueous vehicle,
a first colorant and a first crosslinked polyurethane dispersoid,
wherein the first colorant is soluble or dispersible in the first
aqueous vehicle, and wherein the weight ratio of the first
polyurethane dispersoid to first colorant is at least about
1.0;
[0160] (b) a second colored ink comprising a second aqueous
vehicle, a second colorant and a second crosslinked polyurethane
dispersoid, wherein the second colorant is soluble or dispersible
in the second aqueous vehicle, and wherein the weight ratio of the
second polyurethane dispersoid to second colorant is at least about
1.0; and
[0161] (c) a third colored ink comprising a third aqueous vehicle,
a third colorant and a third crosslinked polyurethane dispersoid,
wherein the third colorant is soluble or dispersible in the third
aqueous vehicle, and wherein the weight ratio of the third
polyurethane dispersoid to third colorant is at least about
1.0.
[0162] Preferably, the first colored ink is a cyan ink, the second
colored ink is a magenta ink and the third colored ink is a yellow
ink.
[0163] In another preferred embodiment, this ink set further
comprises (d) a fourth colored ink comprising a fourth aqueous
vehicle, a fourth colorant and a fourth crosslinked polyurethane
dispersoid, wherein the fourth colorant is soluble or dispersible
in the fourth aqueous vehicle, and wherein the weight ratio of the
fourth polyurethane dispersoid to fourth colorant is at least about
1.0. Preferably this fourth colored ink is a black ink.
[0164] The ink set may further comprise one or more
"gamut-expanding" inks, including different colored inks such as an
orange ink, a green ink, a red ink and/or a blue ink, and
combinations of full strength and light strengths inks such as
light cyan and light magenta. These "gamut-expanding" inks are
particularly useful in textile printing for simulating the color
gamut of analog screen printing, such as disclosed in previously
incorporated US20030128246.
[0165] Method of Printing
[0166] The inks and ink sets of the present invention can be by
printing with any inkjet printer. The substrate can be any suitable
substrate including plain paper (such as standard
elecrophotographic papers), treated paper (such as coated papers
like photographic papers), textile, and non-porous substrates
including polymeric films such as polyvinyl choride and
polyester.
[0167] A particularly preferred use of the inks and ink sets of the
present invention is in the inkjet printing of textiles. Textiles
include but are not limited to cotton, wool, silk, nylon, polyester
and the like, and blends thereof. The finished form of the textile
includes, but is not limited to, fabrics, garments, furnishings
such as carpets and upholstery fabrics, and the like. Additionally,
fibrous textile materials that come into consideration are
especially hydroxyl-group-containing fibrous materials, including
but not limited to natural fibrous materials such as cotton, linen
and hemp, and regenerated fibrous materials such as viscose and
lyocell. Particularly preferred textiles include viscose and
especially cotton. Further fibrous materials include wool, silk,
polyvinyl, polyacrylonitrile, polyamide, aramide, polypropylene and
polyurethane. The said fibrous materials are preferably in the form
of sheet-form textile woven fabrics, knitted fabrics or webs.
[0168] Suitable commercially available inkjet printers designed for
textile printing include, for example, DuPont.RTM. Artistri.RTM.
2020 and 3210 Textile Printers (E.I. du Pont de Nemours and
Company, Wilmington, Del.), Textile Jet (Mimaki USA, Duluth, Ga.),
DisplayMaker Fabrijet (MacDermid ColorSpan, Eden Prairie, Minn.),
Amber, Zircon, and Amethyst (Stork.RTM.).
[0169] The printed textiles may optionally be post processed with
heat and/or pressure, such as disclosed in previously incorporated
US20030160851.
[0170] Upper temperature is dictated by the tolerance of the
particular textile being printed. Lower temperature is determined
by the amount of heat needed to achieve the desired level of
durability. Generally, fusion temperatures will be at least about
80.degree. C. and preferably at least about 140.degree. C., more
preferably at least about 160.degree. C. and most preferably at
least about 180.degree. C.
[0171] Fusion pressures required to achieve improved durability can
be very modest. Thus, pressures can be about 3 psig, preferably at
least about 5 psig, more preferrable at least about 8 psig and most
preferably at least about 10 psig. Fusion pressures of about 30 psi
and above seem to provide no additional benefit to durability, but
such pressures are not excluded.
[0172] The duration of fusion (amount of time the printed textile
is under pressure at the desired temperature) is not believed to be
particularly critical. Most of the time in the fusion operation
generally involves bringing the print up to the desired
temperature. Once the print is fully up to temperature, the time
under pressure can be brief (seconds).
[0173] This invention now will be further illustrated, but not
limited, by the following examples.
EXAMPLES
[0174] Tests used to characterize the polyurethane dispersoids, the
inks and the printed textiles were those commonly used in the art.
Some specific procedures are listed
[0175] Printing and Testing Techniques
[0176] Inkjet printers used in the following examples were:
[0177] (1) a print system with a stationery print head mount with
up to 8 print heads, and a media platen. The printheads were from
Xaar (Cambridge, United Kingdom). The media platen held the
applicable media and traveled underneath the print heads. The
sample size was 7.6 cm by 19 cm. Unless otherwise noted this print
system was used to print the test samples.
[0178] (2) Seiko IP-4010 printer configured to accept fabrics
[0179] (3) DuPont.RTM. Artistri.RTM. 2020 printer.
[0180] The fabrics used were obtained from Testfabrics, Inc,
(Pittston Pa.) namely: (1) 100% cotton fabric style # 419W, which
is a bleached, mercerized combed broadcloth (133.times.72); (2)
Polyester/cotton fabric style # 7435M, which is a 65/35 poplin
mercerized and bleached; and (3) Polyester fabric style # XXXX,
which is a 65/35 poplin mercerized and bleached.
[0181] In some examples, the printed textile was fused at elevated
temperature and pressure. Two different fusing apparatus were
employed:
[0182] (1) a Glenro (Paterson, N.J.) Bondtex.TM. Fabric and Apparel
Fusing Press which moves the printed fabric between two heated
belts equipped with adjustable pneumatic press and finally through
a nip roller assembly; and
[0183] (2) a platen press, assembled for the purpose of precisely
controlling temperature and pressure. The platen press was
comprised of two parallel 6" square platens with embedded resistive
heating elements that could be set to maintain a desired platen
temperature. The platens were fixed in a mutually parallel position
to a pneumatic press that could press the platens together at a
desired pressure by means of adjustable air pressure. Care was
taken to be sure the platens were aligned so as to apply equal
pressure across the entire work piece being fused. The effective
area of the platen could be reduced, as needed, by inserting a
spacer (made, for example from silicone rubber) of appropriate
dimensions to allow operation on smaller work pieces.
[0184] The standard temperature for the fusing step in the examples
was 160.degree. C. unless otherwise indicated.
[0185] The printed textiles were tested according to methods
developed by the American Association of Textile Chemists and
Colorists, (MTCC), Research Triangle Park, N.C. The AATCC Test
Method 61-1996, "Colorfastness to Laundering, Home and Commercial:
Accelerated", was used. In that test, colorfastness is described as
"the resistance of a material to change in any of its color
characteristics, to transfer of its colorant(s) to adjacent
materials or both as a result of the exposure of the material to
any environment that might be encountered during the processing,
testing, storage or use of the material." Tests 2A and 3A were done
and the color washfastness and stain rating were recorded. The
ratings for these tests are from 1-5 with 5 being the best result,
that is, little or no loss of color and little or no transfer of
color to another material, respectively.
[0186] The colorant dispersion, or other stable aqueous colorant,
was prepared by techniques known in the inkjet art. A black pigment
dispersion was used for the ink examples except where noted.
[0187] Ingredients and Abbreviations
[0188] APTES=aminopropyltriethoxysilane
[0189] APTMS=aminopropyltrimethoxy silane
[0190] BZMA=benzyl methacrylate
[0191] CHBMA=1,3-cyclohexane bis(methyl amine)
[0192] DBTL=dibutyltindilaurate
[0193] DMEA=dimethylethanolamine
[0194] DMIPA=dimethylisopropylamine
[0195] DMPA=dimethylol propionic acid
[0196] EDA=ethylene diamine
[0197] EDTA=ethylenediamine tetraacetic acid
[0198] ETEGMA=ethoxytriethylenglycolmethacrylate
[0199] HDI=1,6-hexamethylene diisocyanate
[0200] IPDA=isophoronediamine
[0201] IPDI=isophoronediisocyanate
[0202] MAA=methyl acrylic acid
[0203] NMP=n-Methyl pyrolidone
[0204] POEA=2-phenoxyethyl acrylate ester
[0205] TEA=triethylamine
[0206] TEOA=triethanolamine
[0207] TETA=triethylenetetramine
[0208] THF=tetrahydrofuran
[0209] Unless otherwise noted, the above chemicals were obtained
from Aldrich (Milwaukee, Wis.) or other similar suppliers of
laboratory chemicals.
[0210] BYK.RTM. 348--a silicone surfactant from Byk-Chemie
(Wallingford, Conn.)
[0211] Cythane.RTM. 3174--an aliphatic polyisocyanate resin from
Cytec (West Patterson, N.J.)
[0212] Desmodur N3400, a hexamethylene diisocyanate 40 wt % dimer
and 60 wt % trimer blend from Bayer (Pittsburgh, Pa.)
[0213] Desmophene C 200--a polyester carbonate diol from Bayer
(Pittsburgh, Pa.)
[0214] GP426--a 2000 molecular weight silicone based diol from
Genesee Silicones, (Flint, Mich.)
[0215] Liponic.TM. EG-1--ethoxylated glycerin humectant from Lipo
Chemicals Inc. (Patterson, N.J.)
[0216] Silwet.RTM. L77--an organosilicone surfactant from GE
Silicones (Wilton, Conn.)
[0217] Surfynol.RTM. 104--a nonionic surfactant from Air Products
(Allentown, Pa.)
[0218] Surfynol.RTM. 485--a nonionic surfactant from Air Products
(Allentown, Pa.)
[0219] Surfynol.RTM. 440--a nonionic surfactant from Air Products
(Allentown, Pa.)
[0220] Terathane.RTM. 1400--a polytetramethylene oxide polyol from
E.I. du Pont de Nemours and Company (Wilmington, Del.)
[0221] Extent of Polyurethane Reaction
[0222] The extent of polyurethane reaction was determined by
detecting NCO % by dibutylamine titration, a common method in
urethane chemistry.
[0223] In this method, a sample of the NCO containing prepolymer is
reacted with a known amount of dibutylamine solution and the
residual amine is back titrated with HCl.
[0224] Particle Size Measurements
[0225] The particle size for the polyurethane dispersions, pigments
and the inks were determined by dynamic light scattering using a
Microtrac.RTM. UPA 150 analyzer from Honey well/Microtrac
(Montgomeryville, Pa.).
[0226] This technique is based on the relationship between the
velocity distribution of the particles and the particle size. Laser
generated light is scattered from each particle and is Doppler
shifted by the particle Brownian motion. The frequency difference
between the shifted light and the unshifted light is amplified,
digitalized and analyzed to recover the particle size
distribution.
[0227] The reported numbers below are the volume average particle
size.
[0228] Solid Content Measurement
[0229] Solid content for the solvent free polyurethane dispersoids
was measured with a moisture analyzer, model MA50 from Sartorius.
For polyurethane dispersoid containing high boiling solvent, such
as NMP, the solid content was then determined by the weight
differences before and after baking in 150.degree. C. oven for 180
minutes
[0230] THF Insolubles Measurement
[0231] THF insolubles content of the polyurethanes was measured by
first mixing 1 gram of the polyurethane dispersoid with 30 grams of
THF in a pre-weighed centrifuge tube. After the solution was
centrifuged for 2 hours at 17,000 rpm, the top liquid layer was
poured out and the non-dissolved gel in the bottom was left. The
centrifuge tube with the non-dissolved gel was re-weighed after the
tube was put in the oven and dried for 2 hours at 110.degree.
C.
[0232] % Micro-gel of polyurethane=((weight of tube and
non-dissolved gel)-(weight of tube))/(sample weight*polyurethane
solid %).
[0233] Preparation of Inks
[0234] Inks used in the examples were made according to standard
procedures in the inkjet art. Ingredient amounts are in weight
percent of the final ink. Polyurethane dispersoid binders and
colorants are quoted on a solids basis.
[0235] As an example of ink preparation, the ink vehicle was
prepared and added with stirring to the polyurethane dispersoid
binders. After stirring until a good dispersion was obtained, the
mixture was then added to the pigment dispersion and stirred for
another 3 hours, or until a good ink dispersion was obtained.
[0236] Preparation of Black Pigment Dispersion
[0237] A black dispersion was prepared by first mixing well the
following ingredients: (i) 210.4 parts by weight (pbw) deionized
water, (ii) 80.3 pbw of a 41.5 wt % (solids) anionic polymeric
dispersant, and (iii) 9.24 pbw of dimethylethanolamine. The anionic
polymer dispersant was a graft co-polymer 66.3/-g-4.2/29.5
POEA/-g-ETEGMA/MAA prepared according to "Preparation of Dispersant
1" from previously incorporated US20030128246, with the ratios of
monomers adjusted to obtain the 66.2/4.2/29.5 instead of the
61.6/5.8/32.6 ratio indicated in the publication.
[0238] To this was gradually added 100 pbw black pigment (Nipex
1801Q, Degussa). After the pigment was incorporated, 100 pbw
deionized water was mixed in to form the millbase, which was
circulated through a media mill for grinding. 55.4 pbw deionized
water was then added for dilution to final strength.
[0239] The resulting 15 wt % dispersion had the following
properties: a viscosity of 8.60 cP (Brookfield viscometer,
20.degree. C.), a pH of about 7.5 and a median particle size of 92
nm.
[0240] Comparative Polyurethane Dispersoid 1 (Comp. PUD 1)
[0241] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 699.2 g Desmophene C 200, 280.0 g acetone and 0.06 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 189.14 g
IPDI was then added to the flask via the addition funnel at
40.degree. C. over 60 min, with any residual IPDI being rinsed from
the addition funnel into the flask with 15.5 g acetone.
[0242] The flask temperature was raised to 50.degree. C., held for
30 minutes then followed by 44.57 g DMPA, then followed by 25.2 g
TEA, was added to the flask via the addition funnel, which was then
rinsed with 15.5 g acetone. The flask temperature was then raised
again to 50.degree. C. and held for 60 minutes.
[0243] With the temperature at 50.degree. C., 1520.0 g deionized
(DI) water was added over 10 minutes, followed by 131.00 g EDA (as
a 6.25% solution in water) over 5 minutes, via the addition funnel,
which was then rinsed with 80.0 g water. The mixture was held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0244] Acetone (-310.0 g) was removed under vacuum, leaving a final
dispersoid of non-crosslinked polyurethane with about 35.0% solids
by weight.
[0245] Comparative Polyurethane Dispersoid 2 (Comp. PUD 2)
[0246] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 540.80 g Desmophene C 200, 139.00 g acetone and 0.08 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 180.20 g
IPDI was then added to the flask via the addition funnel over 60
min, with any residual IPDI being rinsed from the addition funnel
into the flask with 27.00 g acetone.
[0247] The flask temperature was raised to 50.degree. C. and held
for about 30 minutes (until the NCO %=5.2). 27.20 g DMPA followed
by 17.4 g TEA was then added to the flask via the addition funnel,
which was then rinsed with 5.00 g of acetone. The flask temperature
was then held at 50.degree. C. for about 60 minutes (until an NCO
%=3.2 was achieved).
[0248] With temperature at 50.degree. C., 797.0 g DI water was
added over 10 minutes, followed by 259.00 g of a 6.25% solution of
EDA in water, over 5 minutes, via the addition funnel, which was
then rinsed with 3.00 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0249] Acetone (-171.0 g) was removed under vacuum, leaving a final
dispersoid of non-crosslinked polyurethane with about 40% solids by
weight.
[0250] Polyurethane Dispersoid 1 (PUD EX 1)
[0251] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 699.2 g Desmophene C 200, 280.0 g acetone and 0.06 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 189.14 g
IPDI was then added to the flask via the addition funnel at
40.degree. C. over 60 min, with any residual IPDI being rinsed from
the addition funnel into the flask with 15.5 g acetone.
[0252] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 44.57 g DMPA followed by 25.2 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
15.5 g acetone. The flask temperature was then raised again to
50.degree. C. until NCO % was 1.14% or less.
[0253] With the temperature at 50.degree. C., 1498.0 g deionized
(DI) water was added over 10 minutes, followed by mixture of 97.5 g
EDA (as a 6.25% solution in water) and 29.7 g TETA (as a 6.25%
solution in water) over 5 minutes, via the addition funnel, which
was then rinsed with 80.0 g water. The mixture was held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0254] Acetone (-310.0 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 35.0% solids by weight.
[0255] For polyurethane dispersoid 1, the crosslinking was achieved
by the TETA.
[0256] Polyurethane Dispersoid 2 (PUD EX 2)
[0257] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 699.2 g Desmophene C 200, 280.0 g acetone and 0.06 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 189.14 g
IPDI was then added to the flask via the addition funnel at
40.degree. C. over 60 min, with any residual IPDI being rinsed from
the addition funnel into the flask with 15.5 g acetone.
[0258] The flask temperature was raised to 50.degree. C., then held
for 30 minutes. 44.57 g DMPA followed by 25.2 g TEA was added to
the flask via the addition funnel, which was then rinsed with 15.5
g acetone. The flask temperature was then raised again to
50.degree. C. and held at 50.degree. C. until NCO % was less than
1.23%.
[0259] With the temperature at 50.degree. C., 1498.0 g deionized
(DI) water was added over 10 minutes, followed by mixture of 24.4 g
EDA (as a 6.25% solution in water) and 118.7 g TETA (as a 6.25%
solution in water) over 5 minutes, via the addition funnel, which
was then rinsed with 80.0 g water. The mixture was held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0260] Acetone (-310.0 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 35.0% solids by weight.
[0261] For polyurethane dispersoid 2 the crosslinking was achieved
by the TETA.
[0262] Polyurethane Dispersoid 3 (PUD EX 3)
[0263] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 375.0 g Desmophene C200, 156.7 g acetone and 0.04 g DBTL. The
contents were heated to 40.degree. C. and mixed well. 107.5 g IPDI
and 18.5 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60 min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 11.3 g
acetone.
[0264] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 31.5 g DMPA followed by 20.2 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
7.4 g of acetone. The flask temperature was then held at 50.degree.
C. until the NCO % was less than 1.23%.
[0265] With temperature at 50.degree. C., 850.0 g DI water was
added over 10 minutes, followed by 100.0 g EDA (as a 6.25% solution
in water) over 5 minutes, via the addition funnel, which was then
rinsed with 50.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0266] Acetone (-176.7 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 33% solids by weight.
[0267] For polyurethane dispersoid 3 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0268] Polyurethane Dispersoid 4 (PUD EX 4)
[0269] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 363.3 g Desmophene C 200, 115.4 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 113.5 g
IPDI was then charged to the flask via the addition funnel over 60
min, with any residual IPDI being rinsed from the addition funnel
into the flask with 5.8 g acetone.
[0270] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 28.9 g DMPA followed by 19.6 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
4.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was less than 1.50%. Then 32.4 g Cythane.RTM. 3174
(Cytec) was charged and held at 50.degree. C. for 5 minutes,
followed by adding 600 g DI water over 10 minutes, and 120.0 g EDA
(as a 6.25% solution in water) over 5 minutes, via the addition
funnel, which was then rinsed with 40.0 g of water. The mixture was
then held at 50.degree. C. for 1 hr, then cooled to room
temperature.
[0271] Acetone (-125.2 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 37% solids by weight.
[0272] For polyurethane dispersoid 4 the crosslinking was achieved
by the polyfunctional isocyanate Cythane.RTM. 3174.
[0273] Polyurethane Dispersoid 5 (PUD EX 5)
[0274] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line was
added 327.64 g Terathane.RTM. 1400, 126.3 g acetone and 0.06 g
DBTL. The contents were heated to 40.degree. C. and mixed well.
115.36 g IPDI was then added to the flask via the addition funnel
at 40.degree. C. over 60 min, with any residual IPDI being rinsed
from the addition funnel into the flask with 7.5 g acetone.
[0275] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.2 g DMPA followed by 12.6 g TEA was added to the
flask via the addition funnel, which was then rinsed with 8.0 g
acetone. The flask temperature was then raised again to 50.degree.
C. held at 50.degree. C. until NCO % was less than 1.58%.
[0276] With the temperature at 50.degree. C., 860.0 g deionized
(DI) water was added over 10 minutes, followed 81.4 g TETA (as a
6.25% solution in water) over 5 minutes, via the addition funnel,
which was then rinsed with 80.0 g water. The mixture was held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0277] Acetone (-141.8 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 30.0% solids by weight.
[0278] For polyurethane dispersoid 4, the crosslinking was achieved
by the TETA.
[0279] Polyurethane Dispersoid 6 (PUD EX 6)
[0280] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 219.95 g Desmophene C 200, 44.10 g acetone and 0.007 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 73.30 g
IPDI was then added to the flask via the addition funnel over 60
min, with any residual IPDI being rinsed from the addition funnel
into the flask with 10.90 g acetone.
[0281] The flask temperature was raised to 50.degree. C. and held
for 30-60 minutes (until the NCO %=5.0). 11.10 g DMPA followed by
8.88 g TEA was then added to the flask via the addition funnel,
which was then rinsed with 4.17 g of acetone. The flask temperature
was then held at 50.degree. C. for about 60 minutes (until the NCO
%=3.0), then cooled to 30.degree. C. 30.40 g APTES was added over
50-60 minutes while controlling the exotherm to not higher than
45.degree. C. The temperature was then raised to 50.degree. C.
until the NCO %=1.4%
[0282] With temperature at 50.degree. C., 544.31 g DI water was
added over 10 minutes, followed by 52.86 g of a 6.25% solution of
EDA in water over 5 minutes, via the addition funnel. The mixture
was then held at 50.degree. C. for 1 hr, then cooled to room
temperature.
[0283] Acetone (-59.17 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 36% solids by weight.
[0284] For polyurethane dispersoid 6, the crosslinking was achieved
by the APTES.
[0285] Properties for Polyurethane Dispersoids 1-6 and Comparative
Polyurethane Dispersoid 1
[0286] Polyurethane dispersoid physical properties and the THF
insolubles were measured and reported in Table 1.
1TABLE 1 Polyurethane Dispersoid Properties Comp PUD PUD PUD PUD
PUD PUD PUD 1 EX 1 EX 2 EX 3 EX 4 EX 5 EX 6 Viscosity (cps) 45 66
20 50 268 184 36 Solids % 36.8 35.2 35.9 32.8 36.9 30 36 pH 7.5
7.48 7.59 7.50 7.5 8.45 8.42 Particle Size 60 65 64 62.5 42 41 85
(nm) THF insolubles, 0 5 18.3 17.8 2.6 84 14.8 %
[0287] Polyurethane dispersoids 1-6 showed a range of THF
insolubles indicating a range of crosslinking. The comparative
example had no THF insolubles.
[0288] Polyurethane Dispersoid 7(PUD EX 7)
[0289] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 340 g Desmophene C 200, 9.8 g GP426, 140 g acetone and 0.04 g
DBTL. The contents were heated to 40.degree. C. and mixed well.
94.2 g IPDI was then added to the flask via the addition funnel at
40.degree. C. over 60 min, with any residual IPDI being rinsed from
the addition funnel into the flask with 7.7 g acetone.
[0290] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.3 g DMPA followed by 12.6 g TEA was added to the
flask via the addition funnel, which was then rinsed with 7.7 g
acetone. The flask temperature was then raised again to 50.degree.
C. and held for 60 minutes.
[0291] With the temperature at 50.degree. C., 780 g deionized (DI)
water was added over 10 minutes, followed by mixture of 13.0 g EDA
(as a 6.25% solution in water) and 63.5 g TETA (as a 6.25% solution
in water) over 5 minutes, via the addition funnel, which was then
rinsed with 40 g water. The mixture was held at 50.degree. C. for 1
hr, then cooled to room temperature.
[0292] Acetone (-155.4 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 34.0% solids by weight.
[0293] For polyurethane dispersoid 7, the crosslinking was achieved
by the TETA.
[0294] Polyurethane Dispersoid 8 (PUD EX 8)
[0295] To a dry, alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 90.0 g Desmophene C 200, 245.5 g Terathane.RTM. 1400, 140 g
acetone and 0.04 g DBTL. The contents were heated to 40.degree. C.
and mixed well. 108.3 g IPDI was then added to the flask via the
addition funnel at 40.degree. C. over 60 min, with any residual
IPDI being rinsed from the addition funnel into the flask with 5.8
g acetone.
[0296] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.3 g DMPA followed by 12.6 g TEA was added to the
flask via the addition funnel, which was then rinsed with 12.5 g
acetone. The flask temperature was then raised again to 50.degree.
C. and held for 60 minutes.
[0297] With the temperature at 50.degree. C., 787 g deionized (DI)
water was added over 10 minutes, followed by 49 g TETA (as a 6.25%
solution in water) over 5 minutes, via the addition funnel, which
was then rinsed with 40 g water. The mixture was held at 50.degree.
C. for 1 hr, then cooled to room temperature.
[0298] Acetone (-157.3 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 34.0% solids by weight.
[0299] For polyurethane dispersoid 8, the crosslinking was achieved
by the TETA.
[0300] Polyurethane Dispersoid 9 (PUD EX 9)
[0301] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 335.0 g of Desmophene C 200, 135 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 82 g IPDI
and 24.5 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60 min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 10.0 g
acetone.
[0302] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.3 g DMPA followed by 13.1 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
10.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was 1.52 or less.
[0303] With temperature at 50.degree. C., 730.0 g DI water was
added over 10 minutes, followed by 96.0 g EDA (as a 6.25% solution
in water) over 5 minutes, via the addition funnel, which was then
rinsed with 40.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0304] Acetone (-155 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 37% solids by weight.
[0305] For polyurethane dispersoid 9 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0306] Polyurethane Dispersoid 10 (PUD EX 10)
[0307] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 335.0 g of Desmophene C 200, 138 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 90 g IPDI
and 27.0 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60 min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 10.0 g
acetone.
[0308] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.8 g DMPA followed by 13.3 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
10.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was 1.8% or less.
[0309] With temperature at 50.degree. C., 716.0 g DI water was
added over 10 minutes, followed by 134.0 g EDA (as a 6.25% solution
in water) over 5 minutes, via the addition funnel, which was then
rinsed with 40.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0310] Acetone (-158 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 39% solids by weight.
[0311] For polyurethane dispersoid 10 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0312] Polyurethane Dispersoid 11 (PUD EX 11)
[0313] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 335.0 g of Desmophene C 200, 142 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 99 g IPDI
and 29.5 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60. min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 10.0 g
acetone.
[0314] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 23.4 g DMPA followed by 13.6 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
10.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was 2.3% or less.
[0315] With temperature at 50.degree. C., 700.0 g DI water was
added over 10 minutes, followed by 174.0 g EDA (as a 6.25% solution
in water) over 5 minutes, via the addition funnel, which was then
rinsed with 40.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0316] Acetone (-162 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 36% solids by weight.
[0317] For polyurethane dispersoid 11 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0318] Polyurethane Dispersoid 12 (PUD EX 12)
[0319] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 349.5 g of Desmophene C 200, 140 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 87 g IPDI
and 16 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60 min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 10.0 g
acetone.
[0320] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.3 g DMPA followed by 12.8 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
10.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was 1.23% or less.
[0321] With temperature at 50.degree. C., 730.0 g DI water was
added over 10 minutes, followed by 159.6 g IPDA (as a 10.0%
solution in water) over 5 minutes, via the addition funnel, which
was then rinsed with 40.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0322] Acetone (-160 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 35% solids by weight.
[0323] For polyurethane dispersoid 12 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0324] Polyurethane Dispersoid 13 (PUD EX 13)
[0325] To a dry alkali- and acid-free flask, equipped with an
addition funnel, a condenser, stirrer and a nitrogen gas line, was
added 350.0 g of Desmophene C 200, 140 g acetone and 0.04 g DBTL.
The contents were heated to 40.degree. C. and mixed well. 87 g IPDI
and 16 g Desmodur N3400 were then charged to the flask via the
addition funnel over 60 min, with any residual isocyanate being
rinsed from the addition funnel into the flask with 10.0 g
acetone.
[0326] The flask temperature was raised to 50.degree. C. and held
for 30 minutes. 22.3 g DMPA followed by 12.8 g TEA was then added
to the flask via the addition funnel, which was then rinsed with
10.0 g of acetone. The flask temperature was held at 50.degree. C.
until NCO % was 1.23% or less.
[0327] With temperature at 50.degree. C., 770.0 g DI water was
added over 10 minutes, followed by 109.25 g CHBMA (as a 12.00%
solution in water) over 5 minutes, via the addition funnel, which
was then rinsed with 40.0 g of water. The mixture was then held at
50.degree. C. for 1 hr, then cooled to room temperature.
[0328] Acetone (-160 g) was removed under vacuum, leaving a final
dispersoid of polyurethane with about 35% solids by weight.
[0329] For polyurethane dispersoid 13 the crosslinking was achieved
by the polyfunctional isocyanate component of the Desmodur
N3400.
[0330] Polyurethane Dispersoid 14 (PUD EX 14)
[0331] Polyurethane dispersoid 14 was a physical blend of
polyurethane dispersoids from Comparative Example 1 and PUD Ex 6.
The material was a 50:50 by weight blend.
[0332] Properties for Polyurethane Dispersoids 7-14
[0333] Polyurethane dispersoid physical properties and the THF
insolubles were measured and reported in Table 2.
2TABLE 2 Properties for Polyurethane Dispersoids 7-14 PUD PUD PUD
PUD PUD PUD PUD PUD EX 7 EX 8 EX 9 EX 10 EX 11 EX 12 EX 13 EX 14
Viscosity 26 414 486 320 24 60 26.5 18 (cps) Solid % 34% 34% 37%
39% 36% 35% 35% 36 PH 7.50 7.50 8.05 8.4 8.4 7.83 7.81 7.50
Particle 71 41 62 94 85 66 59 NA Size (nm) THF insolubles 14.7% 8%
14% 31% 39% NA NA NA
[0334] Set 1: Tests of Crosslinked Polyurethane Dispersoids
[0335] The composition for Ink Examples A-F and Comparative Ink A
are listed in Table 3. The preparation of the black dispersion was
described previously.
3TABLE 3 Composition of Ink Examples Comp. Ink A A B C D E F Black
dispersion 4.25% 4.25% 3.43% 4.25% 4.12% 4.25% 4.25% (% pigment)
Comp PUD 1 10% -- -- PUD EX 1 11% PUD EX 2 -- 13.09% -- -- -- PUD
EX 3 -- -- 10% -- -- PUD EX 4 11% PUD EX 5 10% PUD EX 6 10%
Dipropylene Glycol 3% 3% 2.37% 3% 2.91% 3% 3% Methyl Ether Glycerol
6.5% 8% 14.23% 9.0% 7.76% 7% 8% Ethylene Glycol 9.5% 11% 9.49% 11%
10.67% 10% 11% Liponic .TM. EG-1 3.5% 4% 5% Surfynol .RTM. 104E
0.2% 0.2% 0.16% 0.2% 0.19% 0.2% 0.2% Silwet .RTM. L77 0.2% 0.2%
0.16% 0.2% 0.19% 0.2% 0.2% Water (to 100%) Bal. Bal. Bal. Bal. Bal.
Bal. Bal. Viscosity (cps) 6.3 7.94 7.98 10.00 7.84 8.3 7.7
[0336] The inks were then printed onto a 419 Cotton test fabric.
The printing apparatus is described above as ink printer (1). After
printing the textile was removed and fused with a platen press at
160.degree. C., 10 psig and a dwell time of 1 minute.
[0337] After printing and fusing, the fabrics were tested according
to the `Colorfastness` MTCC Test Method 61-1996 as described
above.
[0338] Unless otherwise noted, all of the fabric testing described
herein was performed on are textiles printed, fused and tested in
this manner.
4TABLE 4 Wash and stain results Comp. Ink A A B C D E F 2A wash
rating 1.5 3.31 3.01 4.0 3.5 3.5 3.0 3A wash rating 0.5 2.64 2.85
4.0 2.5 2.0 2A stain rating 2.31 4.36 4.78 3A stain rating 3.31
4.57 4.0
[0339] The washfastness and stain ratings show that the crosslinked
polyurethane dispersoid containing ink formulations A-F (in
accordance with the invention) significantly improve washfastness
and stain rating relative to the comparative example.
[0340] Set 2: Crosslinked Polyurethane Dispersoids with Different
Colors
[0341] Inks were prepared according to the recipes listed in Table
6. For the inks, the pigments and dispersion are listed in Table 5.
Table 7 lists the washfastness and stain rating results for these
colored inks.
5TABLE 5 Colored Inks, Pigment Types and Polymeric Dispersants
Color Pigment type Polymeric Dispersant Yellow PY 14
BzMA//MAA/ETEGMA (13//13/7.5) Magenta PR 122 BzMA//MAA/ETEGMA
(13//13/7.5) Cyan PB 153 BzMA//MAA (13//10) Blue PB 60
BzMA//MAA/ETEGMA (13//13/7.5) Orange PO 34 BzMA//MAA/ETEGMA
(13//13/7.5) Notes: BzMA//MAA(13//10) was prepared using the
procedure "Preparation of Dispersant 2" from previously
incorporated US20030128246. BzMA//MAA/ETEGMA (13//13/7.5) was
prepared using the procedure "Preparation of Dispersant 3" from
previously incorporated US20030128246.
[0342]
6TABLE 6 Ink compositions of other ink with different colors and
viscosity data Yellow Magenta Cyan Blue Orange Ink Example G H I J
K L M N O P Dispersion (pigment %) 4.25% 4.25% 4.25% 4.25% 3.0%
3.0% 3.0% 3.0% 4.25% 4.25% PUD EX1 5.7% 6.4% 6.0% 10.3% 6.9% PUD
EX2 8.0% 8.7% 6.0% 13.9% 9.4% Propylene Glycol 10% 10% 10.0% 10.0%
5.0% 5.0% 5.0% 5.0% 10% 10% Methyl Ether Glycerol 8.83% 8.83% 5.0%
5.0% 18.7% 19.3% 14.0% 14.0% 5.0% 5.0% Ethylene Glycol 5.0% 5.0%
Liponic .TM. EG-1 5.0% 5.0% 5.0% 5.0% 6.0% 6.0% 5.0% 5.0% 5.0% 5.0%
Surfynol .RTM. 104E 0.17% 0.17% 0.2% 0.25 0.2% 0.2% Surfynol .RTM.
485E 0.33% 0.33% Surfynol .RTM. 440 1.0% 1.0% 0.5% 0.5% Water (to
100%) Balance Balance Balance Balance Balance Balance Balance
Balance Balance Balance Viscosity (cps) 8.14 8.32 7.7 8.1 NA NA NA
NA NA NA
[0343]
7TABLE 7 Washfastness Results of Different Colors Color Ink Example
Yellow Magenta Cyan Blue Orange Wash test G H I J K L M N O P 2A
Wash 4.23 4.19 3.60 3.91 3.32 3.72 3.24 3.62 3.30 3.55 Rating 3A
Wash 3.65 3.70 3.00 3.27 3.00 3.31 2.51 2.98 2.62 2.84 Rating 2A
Stain 4.36 4.84 4.43 4.73 4.26 4.72 Rating 3A Stain 2.68 4.48 2.53
4.42 2.64 4.09 Rating Washfastness and stain rating vary with
different ink colors.
[0344] Set 3: Evaluation of Crosslinked Polyurethane Dispersoid
Preparation Differences and Fusing Changes
[0345] A third set inks was prepared and tested for differences in
polyurethane preparation (polyurethane dispersoids 7 and 9-14) and
fusion conditions. The ink compositions Q-W with black pigment are
shown in Table 8, and a summary of test results is shown in Table
9.
8TABLE 8 Ink Compositions for Polyurethane Dispersoids 7 and 9-14
Ink Example Q R S T U V W Black dispersion 4.25% 4.25% 4.25% 4.25
4.25% 4.25 4.25% (% pigment) PUD EX 7 13% PUD EX 9 13% PUD EX 10
13% PUD EX 11 13% PUD EX 12 13% PUD EX 13 13% PUD EX 14 13%
Glycerol 11.5% 10% 12% 14% 12% 12% 11.5% Ethylene Glycol 12% 12%
12% 12% 12% 12% 12% Surfynol .RTM. 104E 0.15% 0.15% 0.15% 0.15%
0.15% 0.15% 0.15% Silwet .RTM. L77 0.15% 0.15% 0.15% 0.15% 0.15%
0.15% 0.15% Water (to 100%) Bal. Bal. Bal. Bal. Bal. Bal. Bal.
Viscosity (cps) 7.56 8.33 7.94 7.56 7.78 7.39 7.44
[0346]
9TABLE 9 Washfastness Results Ink Example Q R S T U V W 2A wash
rating 2.7 3.2 4.0 3.7 2.8 3.1 1.37 3A wash rating 1.7 2.6 3.1 3.8
2.2 2.1 0.46 2A stain rating 4.72 4.6 4.8 4.7 4.4 4.4 4.64 3A stain
rating 2.75 3.7 4.2 3.2 2.0 2.1 3.08
[0347] Ink W, which was prepared from the polyurethane dispersoid
50/50 wt % blend described in PUD EX 14 (physical mixture of
crosslinked polyurethane dispersoid with a non-crosslinked
polyurethane dispersoid), resulted in lower wash ratings (but
comparable stain ratings) when compared to a crosslinked
polyurethane only.
[0348] Set 4: Washfastness at Different Fusing Temperatures
[0349] A black ink prepared according to the recipe described above
for Ink B, and using a polyurethane made according to the recipe
for Example PUD EX 2, was printed on 419 cotton and the printed
textile was fused at different temperatures. The results are shown
in the Table 11.
10TABLE 11 Washfastness at Different Fusing Temperatures. Ink
Example Y Washfastness, 419 cotton: Temp 2A 3A 160.degree. C. 3.09
2.01 180.degree. C. 4.43 3.09 200.degree. C. 3.59 1.5
[0350] Washfastness is improved with higher temperatures with 419
cotton and this ink formulation.
[0351] Set 5: Wash Fastness at Higher Temperatures
[0352] Magenta ink prepared according to the recipe Ink I, and
using a polyurethane made according to the recipe for PUD EX 2, was
printed on 419 cotton and the printed textile was fused at
different temperatures. After the textile was treated at the
indicated temperature, it was exposed with the platen press fuser
at 10 psig and for 1 minute dwell time. The results of these
experiments are shown on Table 12.
11TABLE 12 Washfastness at Different Fusing Temperatures. Ink
Example Z No 160.degree. Fusing C. 170.degree. C. 180.degree. C.
190.degree. C. 200.degree. C. 2A washfastness 1.5 3.1 3.6 4.4 4.4
4.1 3A Washfastness 0.5 2.2 2.5 3.2 3.5 3.4
[0353] For this set of tests, the washfastness improved with fusing
and at higher temperatures.
[0354] Set 6: Washfastness Tested on Different Fabrics
[0355] A black ink prepared according to recipe described above for
Ink B, and using a polyurethane made according to the recipe for
PUD EX 2, was used to print 419 cotton, 7435 poly/cotton blend and
755 polyester test samples. The printing was done using with ink
printer (1) and the textiles were fused at 160.degree. C., 10 psig
platen pressure and with a dwell time of one minute. The
washfastness and crock were tested for these samples. Crock test
procedures are described in the AATCC Test Method mentioned
above.
12TABLE 13 Washfastness on different fabrics: Ink Example R 2A 3A
Wet wash wash 2A stain 3A stain Dry crock crock 419 cotton 3.5 2.6
4.3 1.9 4.7 2.6 7435 Poly/cotton 2.1 1.5 3.8 1.8 4.9 2.3 blend 755
polyester 2.1 1.5 3.5 1.6 4.7 2.6
[0356] Set 7: Polyurethane Dispersoids with Different NCO/OH
Ratios
[0357] Polyurethane dispersoids were prepared by methods using the
recipes listed above for PUD EX 9 (1.27 ratio of NCO/OH), PUD EX 10
(1.4 ratio of NCO/OH) and PUD EX 11(1.5 NCO/OH ratio). As
indicated, three different NCO/OH ratios were tested. The inks
listed in Table 8 were used to print cotton samples, which were
tested for washfastness. Table 14 shows the results.
13TABLE 14 Variation in polyurethane NCO/OH ratios NCO/OH// 419
cotton 7435 poly/cotton blend Ink Example THF insoluble 2A 3A 2A 3A
1.27//R 4% 3.2 2.6 2.1 1.9 1.4//S 31% 4 3.1 2.3 1.9 1.5//T 38% 3.7
3.8 2.6 2
[0358] Higher NCO/OH gave improved washfastness, especially on
cotton. The amount of THF insolubles also increased with increasing
NCO/OH ratio over the range tested.
[0359] Set 8: Polyurethane Dispersoids with Different Chain
Extenders.
[0360] Polyurethane dispersoids were prepared with three different
chain extenders according to PUD Ex 3 (EDA), PUD Ex 12 (IPDA) and
PUD Ex 13 (CHBMA). The dispersoids were used in inks are listed in
Tables 3 and 8, and cotton samples were printed and tested for
washfastness.
14TABLE 15 Polyurethane dispersoids with different chain extenders
Chain 419 7435 poly/ extender/Ink cotton cotton blend Example 2A 3A
2A 3A EDA/C 3.7 2.9 2 1.7 IPDA/U 2.8 2.2 1.9 1.5 CHBMA/V 3.1 2.1
1.2 1.7
[0361] Based on these tests, the EDA results in the best
washfastness.
[0362] Set 9: Polyurethane Dispersoids with Different
Neutralization
[0363] Polyurethane dispersoids were prepared with two different
neutralizing agents by the methods shown in PUD EX 3. For PUD Ex 3,
the neutralizing agent was triethylamine (TEA). For the alternative
neutralizing agent, a molar equivalent of DMIPA was used. For the
DMIPA neutralizer, the same ink formulation is used as Ink C. The
dispersoids were used in ink, cotton printed and tested for
washfastness.
15TABLE 16 Polyurethane Dispersoid with Different Neutralizing
Agents 419 7435 poly/ Neutralizer/ cotton cotton blend Ink Example
2A 3A 2A 3A TEA/C 3.7 2.9 2 1.7 DMIPA/AA 4.5 2.4 2.1 1.2
[0364] No different washfastness was determined for the two
neutralizing agents. The printability of the DMIPA was not as good
as the TEA.
[0365] Set 10: Washfastness for Different Polyurethane
Dispersoids
[0366] Three different polyurethane dispersoids were prepared.
Entry a is prepared by the same process as PUD EX 6. Entry b and
Entry c (Table 17) were prepared by the same process as described
in Example 2. The dispersoids were used to prepare inkjet inks,
printed on cotton, fused at different temperatures and tested for
washfastness.
16TABLE 17 Test of Different Polyurethane Dispersoids and Different
Temperatures Prep of PUD dispersoid/ procedure listed Wash
above.//Ink Example THF insolubles test 160.degree. C. 170.degree.
C. 180.degree. C. 190.degree. C. 200.degree. C. a. similar to
example 84% 2A 2 3 3 4 4.5 6//AB 3A 1.5 2 2 2.5 b. similar to
Example 40% 2A 3.5 4 4.5 4.5 4.5 2//AC 3A 2.5 2.5 3 3.5 3.5 c.
similar to Example 4.5% (9.3%) 2A 4 4.5 4.5 4.5 4 2//AD (Footnote
1) 3A 2.5 3.5 3 3 3 1) This preparation was performed at a large
scale, about 50 times larger than Example a. The temperature of the
water for inversion was ambient, not heated as in example b and the
TETA source was Akzo Chemical.
[0367] Different polyurethane dispersoid preparations resulted in
similar washfastness performance; washfastness improved with higher
temperature treatment. With higher crosslink density, higher fusing
temperatures were needed to achieve better washfastness.
[0368] Set 11: Ink Stability
[0369] Inks of the instant invention generally are storage stable.
Thus, the instant inks can sustain elevated temperature in a closed
container for extended periods (e.g. 70.degree. C. for 7 days)
without substantial increase in viscosity or particle size.
[0370] Ink Example B was heated at 70.degree. C. for 7 days and
physical properties were measured.
17TABLE 18 Storage stability Before aging After aging Viscosity
7.98 7.52 pH 7.81 7.81 Particle size 66 68 D50(nm) <202.4 nm
100% 97.5%
[0371] This ink was judged to be stable.
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