U.S. patent application number 17/266964 was filed with the patent office on 2021-10-07 for textile printing.
The applicant listed for this patent is Hewlett-Packard Development Company, L.P.. Invention is credited to Ronald A. Askeland, Blair A. Butler, Dennis Z. Guo, Jie Zheng.
Application Number | 20210310188 17/266964 |
Document ID | / |
Family ID | 1000005677817 |
Filed Date | 2021-10-07 |
United States Patent
Application |
20210310188 |
Kind Code |
A1 |
Askeland; Ronald A. ; et
al. |
October 7, 2021 |
TEXTILE PRINTING
Abstract
In an example of a textile printing method, a thermally curable
ink composition is applied on a fabric substrate. The thermally
curable ink composition includes from about 1 wt % active to about
6 wt % active of a pigment that absorbs ultraviolet radiation,
infrared radiation, or a combination thereof, based on a total
weight of the thermally curable ink composition; from about 2 wt %
active to about 20 wt % active of a polymeric binder, based on the
total weight of the thermally curable ink composition; and an
aqueous ink vehicle. In the method, the pigment of the thermally
curable ink composition is selectively heated on the fabric
substrate by exposing the fabric substrate to an emission
wavelength from a narrow wavelength light source for a total
exposure time of 3 seconds or less. The selective heating thermally
fixes the pigment to the fabric substrate.
Inventors: |
Askeland; Ronald A.; (San
Diego, CA) ; Butler; Blair A.; (San Diego, CA)
; Zheng; Jie; (San Diego, CA) ; Guo; Dennis
Z.; (San Diego, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hewlett-Packard Development Company, L.P. |
Spring |
TX |
US |
|
|
Family ID: |
1000005677817 |
Appl. No.: |
17/266964 |
Filed: |
November 29, 2018 |
PCT Filed: |
November 29, 2018 |
PCT NO: |
PCT/US2018/063043 |
371 Date: |
February 8, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D06P 5/30 20130101; D06P
1/44 20130101; D06P 5/002 20130101; D06P 5/2083 20130101; D06P
5/2077 20130101 |
International
Class: |
D06P 5/20 20060101
D06P005/20; D06P 1/44 20060101 D06P001/44; D06P 5/00 20060101
D06P005/00; D06P 5/30 20060101 D06P005/30 |
Claims
1. A textile printing method, comprising: applying a thermally
curable ink composition on a fabric substrate, the thermally
curable ink composition including: from about 1 wt % active to
about 6 wt % active of a pigment that absorbs ultraviolet
radiation, infrared radiation, or combinations thereof, based on a
total weight of the thermally curable ink composition; from about 2
wt % active to about 20 wt % active of a polymeric binder, based on
the total weight of the thermally curable ink composition; and an
aqueous ink vehicle; and selectively heating the pigment of the
thermally curable ink composition applied on the fabric substrate
by exposing the fabric substrate to an emission wavelength from a
narrow wavelength light source for a total exposure time of 3
seconds or less, thereby thermally fixing the pigment to the fabric
substrate.
2. The textile printing method as defined in claim 1 wherein the
narrow wavelength light source is a light emitting diode that emits
emission wavelengths ranging from about 365 nm to about 400 nm.
3. The textile printing method as defined in claim 1, further
comprising setting the narrow wavelength light source so that
energy exposure ranges from about 2 J/cm.sup.2 to about 28
J/cm.sup.2.
4. The textile printing method as defined in claim 1 wherein: the
applying of the thermally curable ink composition is accomplished
in multiple print passes; and the method further comprises exposing
the fabric substrate to the emission wavelength from the narrow
wavelength light source after each print pass for a time less than
the total exposure time.
5. The textile printing method as defined in claim 4 wherein the
time for exposing the fabric substrate to the emission wavelength
from the narrow wavelength light source after each print pass
ranges from about 0.1 second to about 1 second.
6. The textile printing method as defined in claim 1 wherein: the
application of the thermally curable ink composition occurs prior
to the selectively heating; and the selectively heating involves
intermittent light source on events and light source off
events.
7. The textile printing method as defined in claim 1, further
comprising warming or cooling the fabric substrate having the
thermally curable ink composition thereon at a temperature below a
fixation temperature of the thermally curable ink composition: i)
before the selectively heating; or ii) concurrently with the
selectively heating; or iii) both before and concurrently with the
selectively heating.
8. The textile printing method as defined in claim 1 wherein the
polymeric binder in the thermally curable ink composition is
selected from the group consisting of a polyester-polyurethane
binder, a polyether-polyurethane binder, a
polycarbonate-polyurethane binder, a latex binder, and combinations
thereof.
9. The textile printing method as defined in claim 1 wherein the
fabric substrate is selected from the group consisting of cotton, a
cotton blend, nylon, a nylon blend, polyester, a polyester blend,
silk, a silk blend, spandex, a spandex blend, rayon, and a rayon
blend.
10. A textile printing method, comprising: applying a pre-treatment
composition on a fabric substrate, the pre-treatment composition
including: a fixing agent selected from the group consisting of a
multivalent metal cation, a cationic polymer, and a combination of
a multivalent metal cation and a cationic polymer; and an aqueous
pre-treatment vehicle; applying a thermally curable ink composition
on the fabric substrate, the thermally curable ink composition
including: from about 1 wt % active to about 6 wt % active of a
pigment that absorbs ultraviolet radiation, infrared radiation, or
combinations thereof, based on a total weight of the thermally
curable ink composition; from about 2 wt % active to about 20 wt %
active of a polymeric binder, based on the total weight of the
thermally curable ink composition; and an aqueous ink vehicle; and
selectively heating the pigment of the thermally curable ink
composition applied on the fabric substrate by exposing the fabric
substrate to an emission wavelength from a narrow wavelength light
source for a total exposure time of 3 seconds or less, thereby
thermally fixing the pigment to the fabric substrate.
11. The textile printing method as defined in claim 10 wherein the
narrow wavelength light source is a light emitting diode that emits
emission wavelengths ranging from about 365 nm to about 400 nm.
12. The textile printing method as defined in claim 10, further
comprising setting the narrow wavelength light source so that the
energy exposure ranges from about 2 J/cm.sup.2 to about 28
J/cm.sup.2.
13. The textile printing method as defined in claim 10 wherein: the
application of the pre-treatment composition occurs prior to the
application of the thermally curable ink composition; the applying
of the thermally curable ink composition is accomplished in
multiple print passes; and the method further comprises exposing
the fabric substrate to the emission wavelength from the narrow
wavelength light source after each print pass for a time less than
the total exposure time.
14. The textile printing method as defined in claim 10 wherein: the
application of the pre-treatment composition occurs prior to the
application of the thermally curable ink composition; the
application of the thermally curable ink composition occurs prior
to the selectively heating; and the selectively heating involves
intermittent light source on events and light source off
events.
15. The textile printing method as defined in claim 10, further
comprising warming or cooling the fabric substrate having the
pre-treatment composition and the thermally curable ink composition
thereon at a temperature below a fixation temperature of the
thermally curable ink composition: i) before the selectively
heating; or ii) concurrently with the selectively heating; or iii)
both before and concurrently with the selectively heating.
Description
BACKGROUND
[0001] Textile printing methods often include rotary and/or
flat-screen printing. Traditional analog printing typically
involves the creation of a plate or a screen, i.e., an actual
physical image from which ink is transferred to the textile. Both
rotary and flat screen printing have great volume throughput
capacity, but also have limitations on the maximum image size that
can be printed. For large images, pattern repeats are used.
Conversely, digital inkjet printing enables greater flexibility in
the printing process, where images of any desirable size can be
printed immediately from an electronic image without pattern
repeats. Inkjet printers are gaining acceptance for digital textile
printing. Inkjet printing is a non-impact printing method that
utilizes electronic signals to control and direct droplets or a
stream of ink to be deposited on media.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] Features of examples of the present disclosure will become
apparent by reference to the following detailed description and
drawings.
[0003] FIG. 1 is a flow diagram illustrating an example of a
printing method;
[0004] FIG. 2 is a flow diagram illustrating an example of a
printing method;
[0005] FIGS. 3A and 3B are schematic diagram of different examples
of a printing system disclosed herein;
[0006] FIG. 4 depicts black and white reproductions of originally
colored photographs of control, example, and comparative black ink
print swaths on cotton after washing;
[0007] FIG. 5 depicts black and white reproductions of originally
colored photographs of control, example, and comparative cyan ink
print swaths on cotton after washing;
[0008] FIG. 6 depicts black and white reproductions of originally
colored photographs of control, example, and comparative black ink
print swaths on nylon after washing;
[0009] FIG. 7 depicts black and white reproductions of originally
colored photographs of control, example, and comparative cyan ink
print swaths on nylon after washing;
[0010] FIG. 8 is a graph depicting the change in optical density
(delta (A) OD) for the control, example, and comparative black and
cyan ink print swaths;
[0011] FIG. 9 is a schematic illustration of a print and different
exposure regions that was used in Example 2;
[0012] FIG. 10A depicts black and white reproductions of originally
colored photographs of first example inks printed on cotton both
before and after washing, where each print included a control
region (untreated control) and an example region (treated with 395
nm UV LED);
[0013] FIG. 10B depicts black and white reproductions of originally
colored photographs of the first example inks printed on cotton
both before and after washing, where each comparative print was
treated with a heat press;
[0014] FIG. 11A depicts black and white reproductions of originally
colored photographs of second example inks printed on cotton both
before and after washing, where each print included a control
region (untreated control) and an example region (treated with 395
nm UV LED);
[0015] FIG. 11B depicts black and white reproductions of originally
colored photographs of the second example inks printed on cotton
both before and after washing, where each comparative print was
treated with a heat press;
[0016] FIG. 12A depicts black and white reproductions of originally
colored photographs of third example inks printed on cotton both
before and after washing, where each print included a control
region (untreated control) and an example region (treated with 395
nm UV LED); and
[0017] FIG. 12B depicts black and white reproductions of originally
colored photographs of the third example inks printed on cotton
both before and after washing, where each comparative print was
treated with a heat press.
DETAILED DESCRIPTION
[0018] The textile market is a major industry, and printing on
textiles, such as cotton, polyester, etc., has been evolving to
include digital printing methods. However, the vast majority of
textile printing (.gtoreq.95%) is still performed by analog
methods, such as screen printing. Multi-color printing with analog
screen printing involves the use of a separate screen for each
color that is to be included in the print, and each color is
applied separately (with its corresponding screen). In contrast,
digital inkjet printing can generate many colors by mixing basic
colors in desired locations on the textile, and thus avoids the
limitations of analog screen printing.
[0019] When inks are digitally printed on textiles, they are
exposed to heating in order to dry the ink and fix the ink colorant
to the fabric. Some heating techniques involve relatively long
exposure times (e.g., several minutes) at lower temperatures in
order to avoid burning or other deleterious effects. This can
prolong the overall printing process. Other heating techniques
utilize ultraviolet (UV) curing, which involves exposure to
ultraviolet light to initiate a photochemical reaction that
generates a crosslinked network. When UV curing is used, the ink or
other liquid used in printing includes a photoinitiator to initiate
the photochemical reaction. This adds additional components to the
overall printing process.
[0020] In the examples disclosed herein, a thermally curable ink
composition is coupled with rapid thermal curing by a narrow
wavelength light source. The thermally curable ink composition
disclosed herein does not undergo a photochemical reaction (and
thus does not include a photoinitiator) when exposed to the UV
and/or IR radiation. Rather, the pigment in the ink absorbs the UV
and/or IR radiation, and as a result, is heated. Because heating
occurs through the pigment's absorption of the UV and/or IR
radiation, the heating is selective, i.e., ink printed areas of the
textile are heated, while non-printed areas of the textile remain
unheated. Heating, and thus pigment fixation to the textile
substrate, occur with 3 seconds or less of UV and/or IR
exposure.
[0021] It has been found that the combination of the thermally
curable ink composition and the rapid thermal curing generates
prints having a desirable optical density and washfastness.
"Washfastness," as used herein, refers to the ability of a print on
a fabric to retain its color after being exposed to washing.
Washfastness can be measured in terms of .DELTA.E. The term
".DELTA.E," as used herein, refers to the change in the L*a*b*
values of a color (e.g., cyan, magenta, yellow, black, red, green,
blue, white) after washing. .DELTA.E can be calculated by different
equations, such as the CIEDE1976 color-difference formula and the
CIEDE2000 color-difference formula, both of which are set forth in
the Examples section herein.
[0022] Throughout this disclosure, a weight percentage that is
referred to as "wt % active" refers to the loading of an active
component of a dispersion or other formulation that is present in
the thermally curable ink composition or a pre-treatment
composition. For example, the pigment may be present in a
water-based formulation (e.g., a stock solution or dispersion)
before being incorporated into the ink composition. In this
example, the wt % actives of the pigment accounts for the loading
(as a weight percent) of the pigment that is present in the ink
composition, and does not account for the weight of the other
components (e.g., water, etc.) that are present in the formulation
with the pigment. The term "wt %," without the term actives, refers
to either i) the loading (in the pre-treatment or thermally curable
ink composition) of a 100% active component that does not include
other non-active components therein, or ii) the loading (in the
pre-treatment or ink composition) of a material or component that
is used "as is" and thus the wt % accounts for both active and
non-active components.
[0023] Thermally Curable Inkjet Ink
[0024] The thermally curable inkjet ink includes from about 1 wt %
active to about 6 wt % active of a pigment that absorbs ultraviolet
radiation, infrared radiation, or a combination thereof, based on a
total weight of the thermally curable ink composition; from about 2
wt % active to about 20 wt % active of a polymeric binder, based on
the total weight of the thermally curable ink composition; and an
aqueous ink vehicle.
[0025] UV and/or IR Absorbing Pigments
[0026] The pigment that is included in the thermally curable inkjet
ink is capable of absorbing ultraviolet radiation having a
wavelength ranging from about 10 nm to about 400 nm, infrared
radiation having a wavelength ranging from about 760 nm to about 1
mm, or both ultraviolet and infrared radiation.
[0027] Carbon black is an example of a black UV and IR absorbing
pigment. Examples of suitable UV absorbing blue or cyan organic
pigments include C.I. Pigment Blue 1, C.I. Pigment Blue 2, C.I.
Pigment Blue 3, C.I. Pigment Blue 15, Pigment Blue 15:3, C.I.
Pigment Blue 15:4, C.I. Pigment Blue 16, C.I. Pigment Blue 18, C.I.
Pigment Blue 22, C.I. Pigment Blue 25, C.I. Pigment Blue 60, C.I.
Pigment Blue 65, C.I. Pigment Blue 66, C.I. Vat Blue 4, and C.I.
Vat Blue 60. Examples of suitable UV absorbing magenta, red, or
violet pigments include C.I. Pigment Red 1, C.I. Pigment Red 2,
C.I. Pigment Red 3, C.I. Pigment Red 4, C.I. Pigment Red 5, C.I.
Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment
Red 9, C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red
12, C.I. Pigment Red 14, C.I. Pigment Red 15, C.I. Pigment Red 16,
C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. Pigment Red 19, C.I.
Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23, C.I.
Pigment Red 30, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I.
Pigment Red 37, C.I. Pigment Red 38, C.I. Pigment Red 40, C.I.
Pigment Red 41, C.I. Pigment Red 42, C.I. Pigment Red 48(Ca), C.I.
Pigment Red 48(Mn), C.I. Pigment Red 57(Ca), C.I. Pigment Red 57:1,
C.I. Pigment Red 88, C.I. Pigment Red 112, C.I. Pigment Red 114,
C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 144,
C.I. Pigment Red 146, C.I. Pigment Red 149, C.I. Pigment Red 150,
C.I. Pigment Red 166, C.I. Pigment Red 168, C.I. Pigment Red 170,
C.I. Pigment Red 171, C.I. Pigment Red 175, C.I. Pigment Red 176,
C.I. Pigment Red 177, C.I. Pigment Red 178, C.I. Pigment Red 179,
C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187,
C.I. Pigment Red 202, C.I. Pigment Red 209, C.I. Pigment Red 219,
C.I. Pigment Red 224, C.I. Pigment Red 245, C.I. Pigment Red 286,
C.I. Pigment Violet 19, C.I. Pigment Violet 23, C.I. Pigment Violet
32, C.I. Pigment Violet 33, C.I. Pigment Violet 36, C.I. Pigment
Violet 38, C.I. Pigment Violet 43, C.I. Pigment Violet 50 and any
co-crystal of quinacridone pigments. Examples of suitable UV
absorbing yellow pigments include C.I. Pigment Yellow 1, C.I.
Pigment Yellow 2, C.I. Pigment Yellow 3, C.I. Pigment Yellow 4,
C.I. Pigment Yellow 5, C.I. Pigment Yellow 6, C.I. Pigment Yellow
7, C.I. Pigment Yellow 10, C.I. Pigment Yellow 11, C.I. Pigment
Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, C.I.
Pigment Yellow 16, C.I. Pigment Yellow 17, C.I. Pigment Yellow 24,
C.I. Pigment Yellow 34, C.I. Pigment Yellow 35, C.I. Pigment Yellow
37, C.I. Pigment Yellow 53, C.I. Pigment Yellow 55, C.I. Pigment
Yellow 65, C.I. Pigment Yellow 73, C.I. Pigment Yellow 74, C.I.
Pigment Yellow 75, C.I. Pigment Yellow 77, C.I. Pigment Yellow 81,
C.I. Pigment Yellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow
94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 97, C.I. Pigment
Yellow 98, C.I. Pigment Yellow 99, C.I. Pigment Yellow 108, C.I.
Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow
113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 117, C.I. Pigment
Yellow 120, C.I. Pigment Yellow 122, C.I. Pigment Yellow 124, C.I.
Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow
133, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment
Yellow 147, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I.
Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow
167, C.I. Pigment Yellow 172, C.I. Pigment Yellow 180, C.I. Pigment
Yellow 185, and C.I. Pigment Yellow 213.
[0028] Solid pigments may be incorporated into the aqueous ink
vehicle, or they may be part of a pigment dispersion that is
incorporated into the aqueous ink vehicle. The pigment dispersion
may include a pigment and a separate dispersant, or may include a
self-dispersed pigment. Whether separately dispersed or
self-dispersed, the pigment can be any of a number of primary or
secondary colors, or black or white. As specific examples, the
pigment may be any color, including, as examples, a cyan pigment, a
magenta pigment, a yellow pigment, a black pigment, a violet
pigment, a green pigment, a brown pigment, an orange pigment, a
purple pigment, a white pigment, or combinations thereof.
[0029] In an example, the pigment is present in the thermally
curable inkjet ink in an amount ranging from about 1 wt % active to
about 6 wt % active of the total weight of the thermally curable
inkjet ink. In another example, the pigment is present in the
thermally curable inkjet ink in an amount ranging from about 1.5 wt
% active to about 4 wt % active of the total weight of the
thermally curable inkjet ink.
[0030] For the pigment dispersions disclosed herein, it is to be
understood that the pigment and separate dispersant or the
self-dispersed pigment (prior to being incorporated into the inkjet
formulation), may be dispersed in water alone or in combination
with an additional water soluble or water miscible co-solvent, such
as 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, glycerol,
2-methyl-1,3-propanediol, 1,2-butane diol, diethylene glycol,
triethylene glycol, tetraethylene glycol, or a combination thereof.
It is to be understood however, that the liquid components of the
pigment dispersion become part of the aqueous ink vehicle in the
thermally curable inkjet ink.
[0031] Polymeric Binder
[0032] The thermally curable inkjet ink also includes a polymeric
binder. Examples of the polymeric binder are selected from the
group consisting of a polyester-polyurethane binder, a
polyether-polyurethane binder, a polycarbonate-polyurethane binder,
and a latex binder. In other example, hybrids of any of these
binders may be used.
[0033] In an example, the thermally curable inkjet ink includes the
polyester-polyurethane binder. In an example, the
polyester-polyurethane binder is a sulfonated
polyester-polyurethane binder. The sulfonated
polyester-polyurethane binder can include diaminesulfonate groups.
In an example, the polyester-polyurethane binder is a sulfonated
polyester-polyurethane binder, and is one of: i) an aliphatic
compound including multiple saturated carbon chain portions ranging
from C.sub.4 to C.sub.10 in length, and that is devoid of an
aromatic moiety, or ii) an aromatic compound including an aromatic
moiety and multiple saturated carbon chain portions ranging from
C.sub.4 to C.sub.10 in length.
[0034] In one example, the sulfonated polyester-polyurethane binder
can be anionic. In further detail, the sulfonated
polyester-polyurethane binder can also be aliphatic, including
saturated carbon chains as part of the polymer backbone or as a
side-chain thereof, e.g., C.sub.2 to C.sub.10, C.sub.3 to C.sub.8,
or C.sub.3 to C.sub.6 alkyl. These polyester-polyurethane binders
can be described as "alkyl" or "aliphatic" because these carbon
chains are saturated and because they are devoid of aromatic
moieties. An example of an anionic aliphatic polyester-polyurethane
binder that can be used is IMPRANIL.RTM. DLN-SD (CAS #375390-41-3;
Mw 45,000 Mw; Acid Number 5.2; Tg -47.degree. C.; Melting Point
175-200.degree. C.) from Covestro. Example components used to
prepare the IMPRANIL.RTM. DLN-SD or other similar anionic aliphatic
polyester-polyurethane binders can include pentyl glycols (e.g.,
neopentyl glycol); C.sub.4 to C.sub.10 alkyldiol (e.g.,
hexane-1,6-diol); C.sub.4 to C.sub.10 alkyl dicarboxylic acids
(e.g., adipic acid); C.sub.4 to C.sub.10 alkyl diisocyanates (e.g.,
hexamethylene diisocyanate (HDI)); diamine sulfonic acids (e.g.,
1-[(2-aminoethyl)amino]-ethanesulfonic acid); etc.
[0035] Alternatively, the sulfonated polyester-polyurethane binder
can be aromatic (or include an aromatic moiety) and can include
aliphatic chains. An example of an aromatic polyester-polyurethane
binder that can be used is DISPERCOLL.RTM. U42 (CAS #157352-07-3).
Example components used to prepare the DISPERCOLL.RTM. U42 or other
similar aromatic polyester-polyurethane binders can include
aromatic dicarboxylic acids, e.g., phthalic acid; C.sub.4 to
C.sub.10 alkyl dialcohols (e.g., hexane-1,6-diol); C.sub.4 to
C.sub.10 alkyl diisocyanates (e.g., hexamethylene diisocyanate
(HDI)); diamine sulfonic acids (e.g.,
1-[(2-aminoethyl)amino]-ethanesulfonic acid); etc.
[0036] Other types of polyester-polyurethanes can also be used,
including IMPRANIL.RTM. DL 1380, which can be somewhat more
difficult to jet from thermal inkjet printheads compared to
IMPRANIL.RTM. DLN-SD and DISPERCOLL.RTM. U42, but still can be
acceptably jetted in some examples, and can also provide acceptable
washfastness results on a variety of fabric types.
[0037] The polyester-polyurethane binders disclosed herein may have
a weight average molecular weight (Mw, g/mol) ranging from about
20,000 to about 300,000. As examples, the weight average molecular
weight can range from about 50,000 to about 500,000, from about
100,000 to about 400,000, or from about 150,000 to about
300,000.
[0038] The polyester-polyurethane binders disclosed herein may have
an acid number that ranges from about 1 mg/g KOH to about 50 mg/g
KOH. For this binder, the term "acid number" refers to the mass of
potassium hydroxide (KOH) in milligrams that is used to neutralize
one gram of the sulfonated polyester-polyurethane binder. To
determine this acid number, a known amount of a sample of the
polyester-polyurethane binder may be dispersed in water and the
aqueous dispersion may be titrated with a polyelectrolyte titrant
of a known concentration. In this example, a current detector for
colloidal charge measurement may be used. An example of a current
detector is the MUtek PCD-05 Smart Particle Charge Detector
(available from BTG). The current detector measures colloidal
substances in an aqueous sample by detecting the streaming
potential as the sample is titrated with the polyelectrolyte
titrant to the point of zero charge. An example of a suitable
polyelectrolyte titrant is poly(diallyldimethylammonium chloride)
(i.e., PolyDADMAC).
[0039] As examples, the acid number of the sulfonated
polyester-polyurethane binder can range from about 1 mg KOH/g to
about 200 mg KOH/g, from about 2 mg KOH/g to about 100 mg KOH/g, or
from about 3 mg KOH/g to about 50 mg KOH/g.
[0040] In an example of the thermally curable inkjet ink, the
polyester-polyurethane binder has a weight average molecular weight
(g/mol) ranging from about 20,000 to about 300,000 and an acid
number ranging from about 1 mg KOH/g to about 50 mg KOH/g.
[0041] The average particle size of the polyester-polyurethane
binders disclosed herein may range from about 20 nm to about 500
nm. As examples, the sulfonated polyester-polyurethane binder can
have an average particle size ranging from about 20 nm to about 500
nm, from about 50 nm to about 350 nm, or from about 100 nm to about
250 nm. The particle size of any solids herein, including the
average particle size of the dispersed polymer binder, can be
determined using a NANOTRAC.RTM. Wave device, from Microtrac, e.g.,
NANOTRAC.RTM. Wave II or NANOTRAC.RTM. 150, etc, which measures
particles size using dynamic light scattering. Average particle
size can be determined using particle size distribution data
generated by the NANOTRAC.RTM. Wave device.
[0042] Other examples of the thermally curable inkjet ink include a
polyether-polyurethane binder. Examples of polyether-polyurethanes
that may be used include IMPRANIL.RTM. LP DSB 1069, IMPRANIL.RTM.
DLE, IMPRANIL.RTM. DAH, or IMPRANIL.RTM. DL 1116 (Covestro
(Germany)); or HYDRAN.RTM. WLS-201 or HYDRAN.RTM. WLS-201K (DIC
Corp. (Japan)); or TAKELAC.RTM. W-6061T or TAKELAC.RTM. WS-6021
(Mitsui (Japan)).
[0043] Still other examples of the thermally curable inkjet ink
include a polycarbonate-polyurethane binder. Examples of
polycarbonate-polyurethanes that may be used as the polymeric
binder include IMPRANIL.RTM. DLC-F or IMPRANIL.RTM. DL 2077
(Covestro (Germany)); or HYDRAN.RTM. WLS-213 (DIC Corp. (Japan));
or TAKELAC.RTM. W-6110 (Mitsui (Japan)).
[0044] In still other examples, the thermally curable inkjet ink
includes a latex polymer binder. The term "latex polymer" generally
refers to any dispersed polymer prepared from acrylate and/or
methacrylate monomers, including an aromatic (meth)acrylate monomer
that results in aromatic (meth)acrylate moieties as part of the
latex. In an example, the latex polymer may be devoid of styrene.
In some examples, the latex particles can include a single
heteropolymer that is homogenously copolymerized. In another
example, a multi-phase latex polymer can be prepared that includes
a first heteropolymer and a second heteropolymer. The two
heteropolymers can be physically separated in the latex particles,
such as in a core-shell configuration, a two-hemisphere
configuration, smaller spheres of one phase distributed in a larger
sphere of the other phase, interlocking strands of the two phases,
and so on. If a two-phase polymer, the first heteropolymer phase
can be polymerized from two or more aliphatic (meth)acrylate ester
monomers or two or more aliphatic (meth)acrylamide monomers. The
second heteropolymer phase can be polymerized from a cycloaliphatic
monomer, such as a cycloaliphatic (meth)acrylate monomer or a
cycloaliphatic (meth)acrylamide monomer. The first or second
heteropolymer phase can include the aromatic (meth)acrylate
monomer, e.g., phenyl, benzyl, naphthyl, etc. In one example, the
aromatic (meth)acrylate monomer can be a phenoxylalkyl
(meth)acrylate that forms a phenoxylalkyl (meth)acrylate moiety
within the latex polymer, e.g. phenoxylether, phenoxylpropyl, etc.
The second heteropolymer phase can have a higher T.sub.g than the
first heteropolymer phase in one example. The first heteropolymer
composition may be considered a soft polymer composition and the
second heteropolymers composition may be considered a hard polymer
composition. If a two-phase heteropolymer, the first heteropolymer
composition can be present in the latex polymer in an amount
ranging from about 15 wt % to about 70 wt % of a total weight of
the polymer particle, and the second heteropolymer composition can
be present in an amount ranging from about 30 wt % to about 85 wt %
of the total weight of the polymer particle. In other examples, the
first heteropolymer composition can be present in an amount ranging
from about 30 wt % to about 40 wt % of a total weight of the
polymer particle, and the second heteropolymer composition can be
present in an amount ranging from about 60 wt % to about 70 wt % of
the total weight of the polymer particle.
[0045] In more general terms, whether there is a single
heteropolymer phase, or there are multiple heteropolymer phases,
heteropolymer(s) or copolymer(s) can include a number of various
types of copolymerized monomers, including aliphatic(meth)acrylate
ester monomers, such as linear or branched aliphatic (meth)acrylate
monomers, cycloaliphatic (meth)acrylate ester monomers, or aromatic
monomers. However, in accordance with the present disclosure, the
aromatic monomer(s) selected for use can include an aromatic
(meth)acrylate monomer. To be clear, reference to an "aromatic
(meth)acrylate" does not include the copolymerization of two
different monomers copolymerized together into a common polymer,
e.g., styrene and methyl methacrylate. Rather, the term "aromatic
(meth)acrylate" refers to a single aromatic monomer that is
functionalized by an acrylate, methacrylate, acrylic acid, or
methacrylic acid, etc.
[0046] The weight average molecular weight (g/mol) of the latex
polymer can be from 50,000 to 500,000, for example. The acid number
of the latex polymer can be from 2 mg KOH/g to 40 mg KOH/g, from 2
mg KOH/g to 30 mg KOH/g, or 3 mg KOH/g to 26 mg KOH/g, or 4 mg
KOH/g to 20 mg KOH/g, for example.
[0047] The latex polymer can be in acid form, such as in the form
of a polymer with (meth)acrylic acid surface groups, or may be in
its salt form, such as in the form of a polymer with
poly(meth)acrylate groups.
[0048] In an example, any of the polyurethane-based polymeric
binders may be present in the thermally curable inkjet ink in a
total amount ranging from about 2 wt % active to about 15 wt %
active of the total weight of the thermally curable inkjet ink. In
another example, the latex polymer can be present in the thermally
curable inkjet ink at a relatively high concentration, e.g., from 5
wt % active to 20 wt % active, from 6 wt % active to 15 wt %
active, or from 7 wt % active to 12 wt % active, for example.
[0049] The polymeric binder (prior to being incorporated into the
thermally curable inkjet ink) may be dispersed in water alone or in
combination with an additional water soluble or water miscible
co-solvent, such as those described for the pigment dispersion. It
is to be understood however, that the liquid components of the
binder dispersion become part of the aqueous liquid vehicle in the
thermally curable inkjet ink.
[0050] Wax
[0051] Some examples of the thermally curable inkjet ink also
include a wax. Examples of suitable waxes include those that are
commercially available from Lubrizol, such as LIQUILUBE.TM. 411,
LIQUILUBE.TM. 405, LIQUILUBE.TM. 488, LIQUILUBE.TM. 443, and
LIQUILUBE.TM. 454; from Michelman, such as ME80825, ME48040,
ME98040M1, ME61335, ME90842, ME91240, and ML160; from Keim-Additec,
such as ULTRALUBE.RTM. E-521/20, ULTRALUBE.RTM. E-7093,
ULTRALUBE.RTM. 7095/1, ULTRALUBE.RTM. E-8046, ULTRALUBE.RTM.
E-502V, and ULTRALUBE.RTM. E-842N, or from BYK, such as
AQUACER.RTM. 2650, AQUACER.RTM. 507, AQUACER.RTM. 533, AQUACER.RTM.
515, AQUACER.RTM. 537, AQUASLIP.TM. 671, and AQUASLIP.TM. 942.
[0052] In an example, the wax may be present in the thermally
curable inkjet ink in a total amount ranging from greater than 0 wt
% active to about 1.5 wt % active of the total weight of the
thermally curable inkjet ink. Other examples of the thermally
curable inkjet ink do not include the wax.
[0053] Aqueous Ink Vehicle
[0054] In addition to the pigment and the polymeric binder, the
thermally curable inkjet ink includes the aqueous ink vehicle.
[0055] As used herein, the term "aqueous ink vehicle" may refer to
the liquid fluid with which the pigment (dispersion) and polymeric
binder are mixed to form a thermal or a piezoelectric inkjet
ink(s). A wide variety of vehicles may be used with the inkjet
ink(s) of the present disclosure. The vehicle may include a
co-solvent, an anti-kogation agent, an anti-decel agent, a
surfactant, a biocide, a chelating agent, a pH adjuster, or
combinations thereof. In an example, the vehicle consists of the
co-solvent, the anti-kogation agent, the anti-decel agent, the
surfactant, the biocide, a pH adjuster, or a combination thereof.
In another example, the vehicle consists of water and the
co-solvent, the anti-kogation agent, the anti-decel agent, the
surfactant, the biocide, a pH adjuster, or a combination thereof.
In still another example, the vehicle consists of the anti-kogation
agent, the anti-decel agent, the surfactant, the biocide, a pH
adjuster, and water. In yet a further example, the vehicle consists
of water and the co-solvent, the anti-kogation agent, the
surfactant, the chelating agent, the biocide, a pH adjuster, or a
combination thereof.
[0056] The vehicle may include co-solvent(s). The co-solvent(s) may
be present in an amount ranging from about 4 wt % to about 30 wt %
(based on the total weight of the inkjet ink). In an example, the
vehicle includes glycerol. Other examples of co-solvents include
alcohols, aliphatic alcohols, aromatic alcohols, diols, glycol
ethers, polyglycol ethers, caprolactams, formamides, acetamides,
and long chain alcohols. Examples of such compounds include primary
aliphatic alcohols, secondary aliphatic alcohols, 1,2-alcohols,
1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propylene
glycol alkyl ethers, higher homologs (C.sub.6-C.sub.12) of
polyethylene glycol alkyl ethers, N-alkyl caprolactams,
unsubstituted caprolactams, both substituted and unsubstituted
formam ides, both substituted and unsubstituted acetamides, and the
like. Specific examples of alcohols may include ethanol, isopropyl
alcohol, butyl alcohol, and benzyl alcohol. Other specific examples
include 2-ethyl-2-(hydroxymethyl)-1,3-propane diol (EPHD),
2-methyl-1,3-propanediol, 1,2-butanediol, dimethyl sulfoxide,
sulfolane, and/or alkyldiols such as 1,2-hexanediol.
[0057] The co-solvent may also be a polyhydric alcohol or a
polyhydric alcohol derivative. Examples of polyhydric alcohols may
include ethylene glycol, diethylene glycol, propylene glycol,
butylene glycol, triethylene glycol, 1,5-pentanediol,
1,2-hexanediol, 1,2,6-hexanetriol, glycerin, trimethylolpropane,
and xylitol. Examples of polyhydric alcohol derivatives may include
an ethylene oxide adduct of diglycerin.
[0058] The co-solvent may also be a nitrogen-containing solvent.
Examples of nitrogen-containing solvents may include 2-pyrrolidone,
1-(2-hydroxyethyl)-2-pyrrolidone, N-methyl-2-pyrrolidone,
cyclohexylpyrrolidone, and triethanolamine.
[0059] An anti-kogation agent may also be included in the vehicle
of a thermal inkjet formulation. Kogation refers to the deposit of
dried ink on a heating element of a thermal inkjet printhead.
Anti-kogation agent(s) is/are included to assist in preventing the
buildup of kogation. In some examples, the anti-kogation agent may
improve the jettability of the thermal inkjet ink. The
anti-kogation agent may be present in the thermal inkjet ink in an
amount ranging from about 0.1 wt % active to about 1.5 wt % active,
based on the total weight of the thermal inkjet ink. In an example,
the anti-kogation agent is present in the thermally curable inkjet
ink in an amount of about 0.5 wt % active, based on the total
weight of the thermally curable inkjet ink.
[0060] Examples of suitable anti-kogation agents include
oleth-3-phosphate (commercially available as CRODAFOS.TM. O3 A or
CRODAFOS.TM. N-3A) or dextran 500k. Other suitable examples of the
anti-kogation agents include CRODAFOS.TM. HCE (phosphate-ester from
Croda Int.), CRODAFOS.RTM. N10 (oleth-10-phosphate from Croda
Int.), or DISPERSOGEN.RTM. LFH (polymeric dispersing agent with
aromatic anchoring groups, acid form, anionic, from Clariant),
etc.
[0061] The vehicle may include anti-decel agent(s). Decel refers to
a decrease in drop velocity over time with continuous firing.
Anti-decel agent(s) is/are included to assist in preventing decel.
In some examples, the anti-decel agent may improve the jettability
of the inkjet ink. The anti-decel agent may be present in an amount
ranging from about 0.2 wt % active to about 5 wt % active (based on
the total weight of the inkjet ink). In an example, the anti-decel
agent is present in the thermally curable inkjet ink in an amount
of about 1 wt % active, based on the total weight of the thermally
curable inkjet ink.
[0062] An example of a suitable anti-decel agent is ethoxylated
glycerin having the following formula:
##STR00001##
in which the total of a+b+c ranges from about 5 to about 60, or in
other examples, from about 20 to about 30. An example of the
ethoxylated glycerin is LIPON IC.RTM. EG-1 (LEG-1, glycereth-26,
a+b+c=26, available from Lipo Chemicals).
[0063] The vehicle of the thermally curable inkjet ink may also
include surfactant(s). In any of the examples disclosed herein, the
surfactant may be present in an amount ranging from about 0.01 wt %
active to about 5 wt % active (based on the total weight of the
inkjet ink). In an example, the surfactant is present in the inkjet
ink in an amount ranging from about 0.05 wt % active to about 3 wt
% active, based on the total weight of the thermally curable inkjet
ink.
[0064] The surfactant may include anionic and/or non-ionic
surfactants. Examples of the anionic surfactant may include
alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene
sulfonate, higher fatty acid salt, sulfate ester salt of higher
fatty acid ester, sulfonate of higher fatty acid ester, sulfate
ester salt and sulfonate of higher alcohol ether, higher alkyl
sulfosuccinate, polyoxyethylene alkylether carboxylate,
polyoxyethylene alkylether sulfate, alkyl phosphate, and
polyoxyethylene alkyl ether phosphate. Specific examples of the
anionic surfactant may include dodecylbenzenesulfonate,
isopropylnaphthalenesulfonate, monobutylphenylphenol monosulfonate,
monobutylbiphenyl sulfonate, monobutylbiphenylsul fonate, and
dibutylphenylphenol disulfonate. Examples of the non-ionic
surfactant may include polyoxyethylene alkyl ether, polyoxyethylene
alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan
fatty acid ester, polyoxyethylene sorbitan fatty acid ester,
polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid
ester, polyoxyethylene glycerin fatty acid ester, polyglycerin
fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty
acid amide, alkylalkanolamide, polyethylene glycol polypropylene
glycol block copolymer, acetylene glycol, and a polyoxyethylene
adduct of acetylene glycol. Specific examples of the non-ionic
surfactant may include polyoxyethylenenonyl phenylether,
polyoxyethyleneoctyl phenylether, and polyoxyethylenedodecyl.
Further examples of the non-ionic surfactant may include silicon
surfactants such as a polysiloxane oxyethylene adduct; fluorine
surfactants such as perfluoroalkylcarboxylate, perfluoroalkyl
sulfonate, and oxyethyleneperfluoro alkylether; and biosurfactants
such as spiculisporic acid, rhamnolipid, and lysolecithin.
[0065] In some examples, the vehicle may include a silicone-free
alkoxylated alcohol surfactant such as, for example, TEGO.RTM. Wet
510 (EvonikTegoChemie GmbH) and/or a self-emulsifiable wetting
agent based on acetylenic diol chemistry, such as, for example,
SURFYNOL.RTM. SE-F (Air Products and Chemicals, Inc.). Other
suitable commercially available surfactants include SURFYNOL.RTM.
465 (ethoxylatedacetylenic diol), SURFYNOL.RTM. 440 (an ethoxylated
low-foam wetting agent) SURFYNOL.RTM. CT-211 (now CARBOWET.RTM.
GA-211, non-ionic, alkylphenylethoxylate and solvent free), and
SURFYNOL.RTM. 104 (non-ionic wetting agent based on acetylenic diol
chemistry), (all of which are from Air Products and Chemicals,
Inc.); ZONYL.RTM. FSO (a.k.a. CAPSTONE.RTM., which is a
water-soluble, ethoxylated non-ionic fluorosurfactant from Dupont);
TERGITOL.RTM. TMN-3 and TERGITOL.RTM. TMN-6 (both of which are
branched secondary alcohol ethoxylate, non-ionic surfactants), and
TERGITOL.RTM. 15-S-3, TERGITOL.RTM. 15-S-5, and TERGITOL.RTM.
15-S-7 (each of which is a secondary alcohol ethoxylate, non-ionic
surfactant) (all of the TERGITOL.RTM. surfactants are available
from The Dow Chemical Co.).
[0066] The chelating agent is another example of an additive that
may be included in the aqueous ink vehicle. When included, the
chelating agent is present in an amount greater than 0 wt % active
and less than or equal to 0.5 wt % active based on the total weight
of the thermally curable inkjet ink. In an example, the chelating
agent is present in an amount ranging from about 0.05 wt % active
to about 0.2 wt % active based on the total weight of the thermally
curable inkjet ink.
[0067] In an example, the chelating agent is selected from the
group consisting of methylglycinediacetic acid, trisodium salt;
4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate;
ethylenediaminetetraacetic acid (EDTA); hexamethylenediamine
tetra(methylene phosphonic acid), potassium salt; and combinations
thereof. Methylglycinediacetic acid, trisodium salt (Na3MGDA) is
commercially available as TRILON.RTM. M from BASF Corp.
4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt monohydrate
is commercially available as TIRON.TM. monohydrate.
Hexamethylenediamine tetra(methylene phosphonic acid), potassium
salt is commercially available as DEQUEST.RTM. 2054 from Italmatch
Chemicals.
[0068] The vehicle may also include biocide(s) (i.e., antimicrobial
agents). In an example, the total amount of biocide(s) in the
thermally curable inkjet ink ranges from about 0.1 wt % active to
about 0.25 wt % active (based on the total weight of the inkjet
ink). In another example, the total amount of biocide(s) in the
inkjet ink is about 0.22 wt % active (based on the total weight of
the inkjet ink). In some instances, the biocide may be present in
the pigment dispersion that is mixed with the vehicle.
[0069] Examples of suitable biocides include the NUOSEPT.RTM.
(Ashland Inc.), UCARCIDE.TM. or KORDEK.TM. or ROCIMA.TM. (Dow
Chemical Co.), PROXEL.RTM. (Arch Chemicals) series, ACTICIDE.RTM.
B20 and ACTICIDE.RTM. M20 and ACTICIDE.RTM. MBL (blends of
2-methyl-4-isothiazolin-3-one (MIT), 1,2-benzisothiazolin-3-one
(BIT) and Bronopol) (Thor Chemicals), AXIDE.TM. (Planet Chemical),
NIPACIDE.TM. (Clariant), blends of
5-chloro-2-methyl-4-isothiazolin-3-one (CIT or CMIT) and MIT under
the tradename KATHON.TM. (Dow Chemical Co.), and combinations
thereof.
[0070] The vehicle may also include a pH adjuster. A pH adjuster
may be included in the thermally curable inkjet ink to achieve a
desired pH (e.g., a pH of about 8.5) and/or to counteract any
slight pH drop that may occur over time. In an example, the total
amount of pH adjuster(s) in the thermally curable inkjet ink ranges
from greater than 0 wt % to about 0.1 wt % (based on the total
weight of the thermal inkjet ink). In another example, the total
amount of pH adjuster(s) in the thermally curable inkjet ink is
about 0.03 wt % (based on the total weight of the thermally curable
inkjet ink).
[0071] Examples of suitable pH adjusters include metal hydroxide
bases, such as potassium hydroxide (KOH), sodium hydroxide (NaOH),
etc. In an example, the metal hydroxide base may be added to the
thermal inkjet ink in an aqueous solution. In another example, the
metal hydroxide base may be added to the thermal inkjet ink in an
aqueous solution including 5 wt % of the metal hydroxide base
(e.g., a 5 wt % potassium hydroxide aqueous solution).
[0072] Suitable pH ranges for examples of the ink can be from pH 7
to pH 11, from pH 7 to pH 10, from pH 7.2 to pH 10, from pH 7.5 to
pH 10, from pH 8 to pH 10, 7 to pH 9, from pH 7.2 to pH 9, from pH
7.5 to pH 9, from pH 8 to pH 9, from 7 to pH 8.5, from pH 7.2 to pH
8.5, from pH 7.5 to pH 8.5, from pH 8 to pH 8.5, from 7 to pH 8,
from pH 7.2 to pH 8, or from pH 7.5 to pH 8.
[0073] The balance of the thermally curable inkjet ink is water. In
an example, deionized water may be used. The water included in the
thermally curable inkjet ink may be: i) part of the pigment
dispersion and/or binder dispersion, ii) part of the vehicle, iii)
added to a mixture of the pigment dispersion and/or binder
dispersion and the vehicle, or iv) a combination thereof. In
examples where the thermally curable inkjet ink is a thermal inkjet
ink, the liquid vehicle is an aqueous based vehicle including at
least 70% by weight of water. In examples where the thermally
curable inkjet ink is a piezoelectric inkjet ink, the liquid
vehicle is a solvent based vehicle including at least 50% by weight
of the co-solvent.
[0074] Pre-treatment Composition
[0075] In some of the examples disclosed herein, a pre-treatment
composition may be printed with the thermally curable inkjet ink.
In an example, the pre-treatment composition a fixing agent
selected from the group consisting of a multivalent metal cation, a
cationic polymer, and a combination of a multivalent metal cation
and a cationic polymer, and an aqueous pre-treatment vehicle.
[0076] Some examples of the pre-treatment composition include the
multivalent metal salt without the cationic polymer. The
multivalent metal salt includes a multivalent metal cation and an
anion. In an example, the multivalent metal salt includes a
multivalent metal cation selected from the group consisting of a
calcium cation, a magnesium cation, a zinc cation, an iron cation,
an aluminum cation, and combinations thereof; and an anion selected
from the group consisting of a chloride anion, an iodide anion, a
bromide anion, a nitrate anion, a carboxylate anion, a sulfonate
anion, a sulfate anion, and combinations thereof.
[0077] It is to be understood that the multivalent metal salt
(containing the multivalent metal cation) may be present in any
suitable amount. In an example, the metal salt is present in an
amount ranging from about 2 wt % to about 15 wt % based on a total
weight of the pre-treatment composition. In further examples, the
metal salt is present in an amount ranging from about 4 wt % to
about 12 wt %; or from about 5 wt % to about 15 wt %; or from about
6 wt % to about 10 wt %, based on a total weight of the
pre-treatment composition.
[0078] Some examples of the pre-treatment composition include the
cationic polymer without the multivalent metal salt. When the
pre-treatment composition is to be thermal inkjet printed, the
cationic polymer included in the pre-treatment composition has a
weight average molecular weight (g/mol) of 100,000 or less. This
molecular weight enables the cationic polymer to be printed by
thermal inkjet printheads. In some examples, the weight average
molecular weight of the cationic polymer ranges from about 800 to
about 40,000. It is expected that a cationic polymer with a weight
average molecular weight higher than 100,000 can be used for
examples of the pre-treatment composition applied by piezoelectric
printheads and analog methods. As such, in other examples, the
cationic polymer may have a weight average molecular weight higher
than 100,000, such as, for example, up to 600,000.
[0079] Examples of the cationic polymer are selected from the group
consisting of poly(diallyldimethylammonium chloride);
poly(methylene-co-guanidine) anion, wherein the anion is selected
from the group consisting of hydrochloride, bromide, nitrate,
sulfate, and sulfonates; a polyamine; and
poly(dimethylamine-co-epichlorohydrin).
[0080] In an example, the cationic polymer is present in an amount
ranging from about 1 wt % active to about 10 wt % active based on a
total weight of the pre-treatment composition. In further examples,
the cationic polymer is present in an amount ranging from about 4
wt % active to about 8 wt % active; or from about 2 wt % active to
about 7 wt % active; or from about 6 wt % active to about 10 wt %
active, based on a total weight of the pre-treatment
composition.
[0081] In still other examples, the multivalent metal cation is
used in combination with the cationic polymer.
[0082] As used herein, the term "aqueous pre-treatment vehicle" may
refer to the liquid fluid in which the multivalent metal salt, or
the cationic polymer, or the multivalent metal salt in combination
with the cationic polymer, is/are mixed to form the pre-treatment
composition.
[0083] In an example of the pre-treatment composition, the aqueous
vehicle includes water and a co-solvent. Examples of suitable
co-solvents for the pre-treatment composition are water soluble or
water miscible co-solvents that may be selected from the group
consisting of glycerol, ethoxylated glycerol,
2-methyl-1,3-propanediol, trimethylolpropane, 1,2-propanediol,
dipropylene glycol, and combinations thereof. Other suitable
examples of co-solvents include polyhydric alcohols or simple
carbohydrates (e.g., trehalose). Still further examples of the
pre-treatment composition co-solvent(s) may include alcohols (e.g.,
diols), ketones, ketoalcohols, ethers (e.g., the cyclic ether
tetrahydrofuran (THF), and others, such as thiodiglycol, sulfolane,
2-pyrrolidone,
1-(2-hydroxyethyl)-2-pyrrolidone,1,3-dimethyl-2-imidazolidinone and
caprolactam; glycols such as ethylene glycol, diethylene glycol,
triethylene glycol, tetraethylene glycol, propylene glycol,
dipropylene glycol, tripropylene glycol, trimethylene glycol,
butylene glycol, and hexylene glycol; addition polymers of
oxyethylene or oxypropylene such as polyethylene glycol,
polypropylene glycol and the like; triols such as glycerol (as
mentioned above) and 1,2,6-hexanetriol; lower alkyl ethers of
polyhydric alcohols, such as ethylene glycol monomethyl ether,
ethylene glycol monoethyl ether, diethylene glycol monomethyl, and
diethylene glycol monoethyl ether; and lower dialkyl ethers of
polyhydric alcohols, such as diethylene glycol dimethyl or diethyl
ether.
[0084] Whether used alone or in combination, the total amount of
the co-solvent(s) may be present in the pre-treatment composition
in an amount ranging from about 5 wt % to about 25 wt % based on a
total weight of the pre-treatment composition. The amounts in this
range may be particularly suitable for the composition when it is
to be dispensed from a thermal inkjet printhead. In another
example, the total amount of the co-solvent(s) may be present in
the pre-treatment composition in an amount ranging from about 10 wt
% to about 18 wt % based on a total weight of the pre-treatment
composition. The co-solvent amount may be increased to increase the
viscosity of the pre-treatment composition for a high viscosity
piezoelectric printhead.
[0085] It is to be understood that water is present in addition to
the co-solvent(s) and makes up a balance of the pre-treatment
composition. As such, the weight percentage of the water present in
the pre-treatment composition will depend, in part, upon the weight
percentages of the other components. The water may be purified
water or deionized water.
[0086] An example of the pre-treatment composition further
comprises an additive selected from the group consisting of a
surfactant, a chelating agent, a buffer, a biocide, and
combinations thereof.
[0087] Some examples of the pre-treatment composition further
include a surfactant. The surfactant may be any surfactant that
aids in wetting, but that does not deleteriously interact with the
salt in the pre-treatment composition. As such, in an example, the
surfactant in the pre-treatment composition is selected from the
group consisting of a non-ionic surfactant and a zwitterionic
surfactant. The amount of the surfactant that may be present in the
pre-treatment composition is 2 wt % active or less (with the lower
limit being above 0) based on the total weight of the pre-treatment
composition. In some examples, the amount of the surfactant ranges
from about 0.05 wt % active to about 1 wt % active based on the
total weight of the pre-treatment composition.
[0088] Examples of suitable non-ionic surfactants include non-ionic
fluorosurfactants, non-ionic acetylenic diol surfactants, non-ionic
ethoxylated alcohol surfactants, non-ionic silicone surfactants,
and combinations thereof. Several commercially available non-ionic
surfactants that can be used in the formulation of the
pre-treatment composition include ethoxylated alcohols/secondary
alcohol ethoxylates such as those from the TERGITOL.RTM. series
(e.g., TERGITOL.RTM. 15-S-30, TERGITOL.RTM. 15-S-9, TERGITOL.RTM.
15-S-7), manufactured by Dow Chemical; surfactants from the
SURFYNOL.RTM. series (e.g., SURFYNOL.RTM. SE-F (i.e., a
self-emulsifiable wetting agent based on acetylenic diol
chemistry), SURFYNOL.RTM. 440 and SURFYNOL.RTM. 465 (i.e.,
ethoxylated 2,4,7,9-tetramethyl 5 decyn-4,7-diol)) manufactured by
Evonik Industries, and the DYNOL.TM. series (e.g., DYNOL.TM. 607
and DYNOL.TM. 604) manufactured by Air Products and Chemicals,
Inc.; fluorinated surfactants, such as those from the ZONYL.RTM.
family (e.g., ZONYL.RTM. FSO and ZONYL.RTM. FSN surfactants),
manufactured by E.I. DuPont de Nemours and Company; alkoxylated
surfactants such as TEGO.RTM. Wet 510 manufactured from Evonik;
fluorinated POLYFOX.RTM. non-ionic surfactants (e.g., PF159
non-ionic surfactants), manufactured by Omnova; silicone
surfactants, such as those from BYK.RTM. 340 series (e.g., BYK.RTM.
345, BYK.RTM. 346, BYK.RTM. 347, BYK.RTM. 348, BYK.RTM. 349)
manufactured by BYK Chemie; or combinations thereof.
[0089] Examples of suitable zwitterionic (amphoteric) surfactants
that may be used in the pre-treatment composition include
coco-betaine, alkyl isothionates, N,N-dimethyl-N-dodecylamine
oxide, N,N-dimethyl-N-tetradecyl amine oxide (i.e., myristamine
oxide), N,N-dimethyl-N-hexadecyl amine oxide,
N,N-dimethyl-N-octadecyl amine oxide,
N,N-dimethyl-N--(Z-9-octadecenyl)-N-amine oxide,
N-dodecyl-N,N-dimethyl glycine, lecithins, phospatidylethanolamine,
phosphatidylcholine, and phosphatidylserine.
[0090] The chelating agent is another example of an additive that
may be included in the pre-treatment composition. When included,
the chelating agent is present in an amount greater than 0 wt %
active and less than or equal to 0.5 wt % active based on the total
weight of the pre-treatment composition. Any example of the
chelating agent described in reference to the thermally curable
inkjet ink may be used in the pre-treatment composition.
[0091] Buffers are another example of an additive that may be
included in the pre-treatment composition. In an example, the total
amount of buffer(s) in the pre-treatment composition ranges from 0
wt % to about 0.5 wt % (with respect to the weight of pre-treatment
composition). In another example, the total amount of buffer(s) in
the ink is about 0.1 wt % (with respect to the weight of
pre-treatment composition).
[0092] Examples of some suitable buffers include TRIS
(tris(hydroxymethyl)aminomethane or Trizma), bis-tris propane, TES
(2-[(2-Hydroxy-1,1-bis(hydroxymethyl)ethyl)amino]ethanesulfonic
acid), MES (2-ethanesulfonic acid), MOPS
(3-(N-morpholino)propanesulfonic acid), HEPES
(4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid), DIPSO
(3-(N,N-Bis[2-hydroxyethyl]amino)-2-hydroxypropanesulfonic acid),
Tricine (N-[tris(hydroxymethyl)methyl]glycine), HEPPSO
(.beta.-Hydroxy-4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid
monohydrate), POPSO (Piperazine-1,4-bis(2-hydroxypropanesulfonic
acid) dihydrate), EPPS
(4-(2-Hydroxyethyl)-1-piperazinepropanesulfonic acid,
4-(2-Hydroxyethyl)piperazine-1-propanesulfonic acid), TEA
(triethanolamine buffer solution), Gly-Gly (Diglycine), bicine
(N,N-Bis(2-hydroxyethyl)glycine), HEPBS
(N-(2-Hydroxyethyl)piperazine-N'-(4-butanesulfonic acid)), TAPS
([tris(hydroxymethyl)methylamino]propanesulfonic acid), AMPD
(2-amino-2-methyl-1,3-propanediol), TABS
(N-tris(Hydroxymethyl)methyl-4-aminobutanesulfonic acid), or the
like.
[0093] Biocides (also referred to herein as antimicrobial agents)
are another example of an additive that may be included in the
pre-treatment composition. In an example, the total amount of
biocide(s) in the pre-treatment composition ranges from about 0 wt
% active to about 0.1 wt % active (with respect to the weight of
the pre-treatment composition). In another example, the total
amount of biocide(s) in the pre-treatment composition ranges from
about 0.001 wt % active to about 0.1 wt % active (with respect to
the weight of the pre-treatment composition). Any example of the
biocide described in reference to the thermally curable inkjet ink
may be used in the pre-treatment composition.
[0094] The pH of the pre-treatment composition can be less than 7.
In some examples, the pH ranges from pH 1 to pH 7, from pH 3 to pH
7, from pH 4.5 to pH 7, etc.
[0095] In an example, the inkjet pre-treatment composition consists
of the listed components and no additional components (such as
water soluble polymers, water repellent agents, etc.). In other
examples, the inkjet pre-treatment composition comprises the listed
components, and other components that do not deleteriously affect
the jettability of the fluid via a thermal- or piezoelectric inkjet
printhead may be added.
[0096] Examples of the pre-treatment composition disclosed herein
may be used in a thermal inkjet printer or in a piezoelectric
printer to pre-treat a textile substrate. The viscosity of the
pre-treatment composition may be adjusted for the type of printhead
that is to be used, and the viscosity may be adjusted by adjusting
the co-solvent level and/or adding a viscosity modifier. When used
in a thermal inkjet printer, the viscosity of the pre-treatment
composition may be modified to range from about 1 centipoise (cP)
to about 9 cP (at 20.degree. C. to 25.degree. C.), and when used in
a piezoelectric printer, the viscosity of the pre-treatment
composition may be modified to range from about 2 cP to about 20 cP
(at 20.degree. C. to 25.degree. C.), depending on the viscosity of
the printhead that is being used (e.g., low viscosity printheads,
medium viscosity printheads, or high viscosity printheads).
[0097] One specific example of the pre-treatment composition
includes the multivalent metal salt in an amount ranging from about
5 wt % to about 15 wt % based on the total weight of the
pre-treatment composition; an additive selected from the group
consisting of a non-ionic surfactant, a chelating agent, an
antimicrobial agent, and combinations thereof; and the aqueous
vehicle, which includes water and an organic solvent (e.g., the
co-solvent).
[0098] Textile Fabrics
[0099] In the examples disclosed herein, the textile fabric is
selected from the group consisting of cotton fabrics, cotton blend
fabrics, nylon fabrics, nylon blend fabrics, polyester fabrics,
polyester blend fabrics, silk fabrics, silk blend fabrics, spandex,
spandex blend fabrics, rayon, and rayon blend fabrics. In a further
example, textile fabric is selected from the group consisting of
cotton fabrics and cotton blend fabrics. Blends may include the
listed material in combination with one or more other material(s).
An example of a tri-blend includes cotton, polyester and
spandex.
[0100] It is to be understood that organic textile fabrics and/or
inorganic textile fabrics may be used for the textile fabric. Some
types of fabrics that can be used include various fabrics of
natural and/or synthetic fibers.
[0101] Example natural fiber fabrics that can be used include
treated or untreated natural fabric textile substrates, e.g., wool,
cotton, silk, linen, jute, flax, hemp, rayon fibers, thermoplastic
aliphatic polymeric fibers derived from renewable resources (e.g.
cornstarch, tapioca products, sugarcanes), etc. Example synthetic
fibers used in the textile fabric/substrate can include polymeric
fibers such as nylon fibers, polyvinyl chloride (PVC) fibers,
PVC-free fibers made of polyester, polyamide, polyimide,
polyacrylic, polypropylene, polyethylene, polyurethane,
polystyrene, polyaramid (e.g., Kevlar.RTM.) polytetrafluoroethylene
(Teflon.RTM.) (both trademarks of E.I. du Pont de Nemours and
Company, Delaware), fiberglass, polytrimethylene, polycarbonate,
polyethylene terephthalate, polyester terephthalate, polybutylene
terephthalate, or a combination thereof. In some examples, the
fiber can be a modified fiber from the above-listed polymers. The
term "modified fiber" refers to one or both of the polymeric fiber
and the fabric as a whole having undergone a chemical or physical
process such as, but not limited to, copolymerization with monomers
of other polymers, a chemical grafting reaction to contact a
chemical functional group with one or both the polymeric fiber and
a surface of the fabric, a plasma treatment, a solvent treatment,
acid etching, or a biological treatment, an enzyme treatment, or
antimicrobial treatment to prevent biological degradation.
[0102] It is to be understood that the terms "textile fabric" or
"fabric substrate" do not include materials commonly known as any
kind of paper (even though paper can include multiple types of
natural and synthetic fibers or mixtures of both types of fibers).
Fabric substrates can include textiles in filament form, textiles
in the form of fabric material, or textiles in the form of fabric
that has been crafted into finished articles (e.g., clothing,
blankets, tablecloths, napkins, towels, bedding material, curtains,
carpet, handbags, shoes, banners, signs, flags, etc.). In some
examples, the fabric substrate can have a woven, knitted,
non-woven, or tufted fabric structure. In one example, the fabric
substrate can be a woven fabric where warp yarns and weft yarns can
be mutually positioned at an angle of about 90.degree.. This woven
fabric can include fabric with a plain weave structure, fabric with
twill weave structure where the twill weave produces diagonal lines
on a face of the fabric, or a satin weave. In another example, the
fabric substrate can be a knitted fabric with a loop structure. The
loop structure can be a warp-knit fabric, a weft-knit fabric, or a
combination thereof. A warp-knit fabric refers to every loop in a
fabric structure that can be formed from a separate yarn mainly
introduced in a longitudinal fabric direction. A weft-knit fabric
refers to loops of one row of fabric that can be formed from the
same yarn. In a further example, the fabric substrate can be a
non-woven fabric. For example, the non-woven fabric can be a
flexible fabric that can include a plurality of fibers or filaments
that are one or both bonded together and interlocked together by a
chemical treatment process (e.g., a solvent treatment), a
mechanical treatment process (e.g., embossing), a thermal treatment
process, or a combination of multiple processes.
[0103] Printing Methods and System
[0104] FIG. 1 depicts an example of the printing method 100. As
shown in FIG. 1, an example the printing method 100 comprises:
applying a thermally curable ink composition on a fabric substrate,
the thermally curable ink composition including: from about 1 wt %
active to about 6 wt % active of a pigment that absorbs ultraviolet
radiation, infrared radiation, or a combination thereof, based on a
total weight of the thermally curable ink composition; from about 2
wt % active to about 20 wt % active of a polymeric binder, based on
a total weight of the thermally curable ink composition; and an
aqueous ink vehicle (reference numeral 102); and selectively
heating the pigment of the thermally curable ink composition
applied on the fabric substrate by exposing the fabric substrate to
an emission wavelength from a narrow wavelength light source for a
total exposure time of 3 seconds or less, thereby thermally fixing
the pigment to the fabric substrate (reference numeral 104).
[0105] As used herein, the phrase "total exposure time" refers to
the total time that the fabric having the ink printed thereon is
exposed to the emission wavelength. In some examples, the total
exposure time may take place during a single event where the light
source is turned on (i.e., light source on event). In other
examples, the total exposure time may take place over a series of
light source on events that are shorter in duration than the total
exposure time and whose sum equals the total exposure time. In some
examples, light source on events may be separated by light source
off events, during which the light source is turned off and the
fabric is not exposed to the emission wavelength. In these
examples, the total time to achieve pigment fixation is longer than
the total exposure time due to the time periods when the light
source is off. However, in these examples, the total exposure time
is still 3 seconds or less because the fabric is not exposure to
the light emission during the off events.
[0106] It is to be understood that any example of the thermally
curable ink composition may be used in the examples of the method
100. It is to be understood that any example of the textile fabric
may also be used in the examples of the method 100. The thermally
curable ink composition may be ejected onto the textile fabric
using any suitable applicator, such as a thermal inkjet printhead,
a piezoelectric printhead, a continuous inkjet printhead, etc. The
applicator may eject the thermally curable ink composition in a
single pass or in multiple passes. As an example of single pass
printing, the cartridge(s) of an inkjet printer deposit the desired
amount of the ink composition during the same pass of the
cartridge(s) across the textile fabric. In other examples, the
cartridge(s) of an inkjet printer deposit the desired amount of the
ink composition over several passes of the cartridge(s) across the
textile fabric. In other examples of the method 100, the thermally
curable ink composition is applied via analog methods, such as
screen printing, spraying, roll-coating, cylindrical pad printing,
etc.
[0107] In one example of the method 100, the narrow wavelength
light source is a light emitting diode having an emission
wavelength ranging from about 10 nm to about 400 nm. In one
example, the narrow wavelength ultraviolet light source is a light
emitting diode having an emission wavelength ranging from about 365
nm to about 395 nm. In another example, the narrow wavelength
ultraviolet light source is a 395 nm light emitting diode. In
another example of the method 100, the narrow wavelength light
source is a light emitting diode having an emission wavelength
ranging from about 760 nm to about 1 mm.
[0108] The UV or IR radiation exposure takes place very rapidly
with the narrow wavelength light source. To avoid overheating of
the pigment, it may be desirable to adjust the settings of the
narrow wavelength light source. For example, the method 100 may
include setting the narrow wavelength light source to a power
setting ranging from about 3.5 W/cm.sup.2 to about 10 W/cm.sup.2.
The power setting may depend, in part, upon the light source used,
the total time for exposure, the distance between the light source
and the textile fabric, etc. Higher power settings may be desirable
for faster throughput systems. In another example, the energy
(radiant) exposure ranges from about 2 J/cm.sup.2 to about 28
J/cm.sup.2. In a specific example, if a power of 10 W/cm.sup.2 is
applied for 1 second, the applied energy is 10 J/cm.sup.2.
[0109] When exposed to the UV or IR radiation, the pigment in the
printed ink absorbs the ultraviolet light or infrared light and
heats up to its fixation temperature. As such, exposure to the
narrow wavelength light source fixes the ink on the textile fabric.
It has been found that the narrow wavelength light source thermally
cures the thermally curable ink composition disclosed herein within
3 seconds or less, and effectively fixes the pigment to the textile
fabric without traditional UV curing components, such as
photoinitiators.
[0110] In some examples of the method 100, the desired amount of
the thermally curable ink composition is deposited in a single pass
or in multiple passes, and then selective heating occurs. In these
examples, the application of the thermally curable ink composition
occurs prior to the selectively heating, and the selectively
heating involves intermittent light source on events and light
source off events. During light source on events, the narrow
wavelength light source is turned on, and during light source off
events, the narrow wavelength light source is turned off. The
intermittent on and off events can effectively heat the pigment in
the printed ink to its fixation temperature without overheating the
pigment. The light source on events may range from about 0.1 second
to about 1.5 seconds. Since the total exposure time is 3 seconds or
less, the number of light source on events will depend upon the
duration of each on event and the desired total exposure time. For
example, when each light source on event is 1 second long, a total
of three light source on events may take place so that the total
exposure time is 3 seconds. A higher number of light source on
events may be used when the on events are shorter in duration. The
light source off events may be long enough to allow the pigments to
cool without allowing the pigments to return to their pre-exposure
temperature.
[0111] In some other examples of the method 100, the desired amount
of the thermally curable ink composition is deposited in multiple
passes, and selective heating occurs after each pass. In these
examples, the applying of the thermally curable ink composition is
accomplished in multiple print passes, and the method 100 further
includes exposing the fabric substrate to the narrow wavelength
light source after each print pass for a time less than the total
exposure time. The time for exposing the fabric substrate to the
narrow wavelength light source after each print pass ranges from
about 0.1 second to about 1.5 seconds. Since the total exposure
time is 3 seconds or less, the duration of the exposure after each
pass will depend upon the number of passes and the desired total
exposure time. For example, when the ink is to be deposited in two
printing passes and the total exposure time is 2 seconds, each of
the exposures may take place for 1 second.
[0112] In some examples of the method 100, warming and/or cooling
of the textile fabric may take place before and/or concurrently
with UV and/or IR radiation exposure. As such, some examples of the
method 100 include warming or cooling the fabric substrate having
the thermally curable ink composition thereon at a temperature
below a fixation temperature of the thermally curable ink
composition: i) before the selectively heating; or ii) concurrently
with the selectively heating; or iii) both before and concurrently
with the selectively heating.
[0113] Warming may be accomplished with a heat source that is
positioned above the textile fabric (e.g., an infrared heating lamp
that provides radiative heating/warming) or below the fabric
substrate (a conductive platen that provides conductive
heating/warming). In an example of the printing method 100, the
temperature at which the fabric substrate is warmed ranges from
about 60.degree. C. to about 100.degree. C. In another example, the
temperature at which the textile fabric is warmed ranges from about
70.degree. C. to about 90.degree. C. It is to be understood that
this warming temperature range may vary, depending upon, e.g., the
fixation temperature of the thermally curable ink. For example, if
the fixation temperature of an ink were 160.degree. C., the warming
temperature may be any suitable temperature below 160.degree.
C.
[0114] Cooling may be accomplished with a cold air source that is
positioned above the textile fabric or below the fabric substrate.
In an example of the printing method 100, the temperature at which
the fabric substrate is cooled ranges from about 20.degree. C. to
about 60.degree. C. It is to be understood that this cooling
temperature range may vary, depending upon, e.g., the fixation
temperature of the thermally curable ink. For example, if the
fixation temperature of an ink were 160.degree. C., the cooling
temperature may be any suitable temperature that enables the fabric
substrate to reach 160.degree. C. without overheating.
[0115] In other instances, warming or cooling may be accomplished
with any suitable bulk temperature control mechanism.
[0116] In an example of the printing method 100, the warming or
cooling takes place for an amount of time ranging from about 0.1
seconds to about 30 seconds. In another example, the warming or
cooling takes place for an amount of time ranging from about 0.1
seconds to about 3 seconds. It is to be understood that this
warming or cooling time range may vary, depending upon, e.g., the
temperature at which warming or cooling takes place and whether
warming or cooling is accomplished prior to and/or concurrently
with the UV and/or IR radiation exposure. For example, if warming
or cooling occurs concurrently with UV and/or IR radiation
exposure, the time for warming or cooling may range from about 0.1
second up to 3 seconds. For another example, if warming occurs
prior to UV and/or IR radiation exposure, the time for warming may
be longer, e.g., up to 30 seconds. It is to be further understood
that examples of the method 100 may be accomplished without
warming/pre-heating or without cooling.
[0117] FIG. 2 depicts another example of the printing method 200.
As shown in FIG. 2, this example the printing method 200 comprises:
applying a pre-treatment composition on a fabric substrate, the
pre-treatment composition including: a fixing agent selected from
the group consisting of a multivalent metal cation, a cationic
polymer, and a combination of the multivalent metal cation and the
cationic polymer; and an aqueous pre-treatment vehicle (reference
numeral 202); applying a thermally curable ink composition on the
fabric substrate, the thermally curable ink composition including:
from about 1 wt % active to about 6 wt % active of a pigment that
absorbs ultraviolet radiation, infrared radiation, or a combination
thereof, based on a total weight of the thermally curable ink
composition; from about 2 wt % active to about 20 wt % active of a
polymeric binder, based on a total weight of the thermally curable
ink composition; and an aqueous ink vehicle (reference numeral 204;
and selectively heating the pigment of the thermally curable ink
composition applied on the fabric substrate by exposing the fabric
substrate to an emission wavelength from a narrow wavelength light
source for a total exposure time of 3 seconds or less, thereby
thermally fixing the pigment to the fabric substrate (reference
numeral 206).
[0118] It is to be understood that any example of the pre-treatment
composition may be used in the examples of the method 200. In some
examples, the pre-treatment composition may be applied digitally
using inkjet technology. Besides inkjet methods, the pretreatment
composition can also be applied to fabric substrates via analog
methods, e.g., spraying, roll-coating, cylindrical pad printing,
etc. With these analog methods, the pre-treatment composition is
applied to the entire fabric substrate.
[0119] It is also to be understood that any example of the
thermally curable ink composition may be used in the examples of
the method 200. The thermally curable ink composition may be
ejected onto the textile fabric using any suitable applicator, such
as a thermal inkjet printhead, a piezoelectric printhead, a
continuous inkjet printhead, etc. The applicator may eject the
thermally curable ink composition in a single pass or in multiple
passes as described in reference to the method 100. In other
examples of the method 200, the thermally curable ink composition
is applied via analog methods, such as screen printing, spraying,
roll-coating, cylindrical pad printing, etc.
[0120] In one example of the method 200, the narrow wavelength
light source is a light emitting diode having an emission
wavelength ranging from about 10 nm to about 400 nm. In one
example, the narrow wavelength ultraviolet light source is a light
emitting diode having an emission wavelength ranging from about 365
nm to about 395 nm. In another example, the narrow wavelength
ultraviolet light source is a 395 nm light emitting diode. In
another example of the method 200, the narrow wavelength light
source is a light emitting diode having an emission wavelength
ranging from about 760 nm to about 1 mm.
[0121] The method 200 may also include setting the narrow
wavelength light source so that the energy exposure ranges from
about 2 J/cm.sup.2 to about 28 J/cm.sup.2.
[0122] When exposed to the UV or IR radiation, the pigment in the
printed ink absorbs the ultraviolet or infrared light and heats up
to its fixation temperature. As such, exposure to the narrow
wavelength light source fixes the ink on the textile fabric. In the
method 200, the multivalent metal salt in the pre-treatment
composition also interacts with pigment in the ink directly on the
fabric substrate, which helps fix the pigment and improve the
optical density.
[0123] In some examples of the method 200, the desired amount of
the pre-treatment composition and of thermally curable ink
composition is deposited in a single pass or in multiple passes,
and then selective heating occurs. In these examples, the
application of the pre-treatment composition occurs prior to the
application of the thermally curable ink composition, the
application of the thermally curable ink composition occurs prior
to the selectively heating, and the selectively heating involves
intermittent light source on events and light source off events.
During light source on events, the narrow wavelength light source
is turned on, and during light source off events, the narrow
wavelength light source is turned off. The intermittent on and off
events can effectively heat the pigment in the printed ink to its
fixation temperature without overheating the pigment. The light
source on events may range from about 0.1 second to about 1.5
seconds. Since the total exposure time is 3 seconds or less, the
number of light source on events will depend upon the duration of
each on event and the desired total exposure time. For example,
when each light source on event is 1 second long, a total of three
light source on events may take place so that the total exposure
time is 3 seconds. A higher number of light source on events may be
used when the on events are shorter in duration. The light source
off events may be long enough to allow the pigments to cool without
allowing the pigments to return to their pre-exposure
temperature.
[0124] In some other examples of the method 200, the desired amount
of the thermally curable ink composition is deposited, the desired
amount of the thermally curable ink composition is deposited in
multiple passes, and selective heating occurs after each pass. In
these examples, the application of the pre-treatment composition
occurs prior to the application of the thermally curable ink
composition, the applying of the thermally curable ink composition
is accomplished in multiple print passes, and the method 200
further includes exposing the fabric substrate to the narrow
wavelength light source after each print pass for a time less than
the total exposure time. The time for exposing the fabric substrate
to the narrow wavelength light source after each print pass ranges
from about 0.1 second to about 1 second. Since the total exposure
time is 3 seconds or less, the duration of the exposure after each
pass will depend upon the number of passes and the desired total
exposure time.
[0125] In some of these examples, the thermally curable ink
composition is printed onto the printed pre-treatment composition
while the pre-treatment composition is wet. Wet on wet printing may
be desirable because less pre-treatment composition may be applied
during this process (as compared to when the pre-treatment
composition is dried prior to ink application), and because the
printing workflow may be simplified without the additional drying.
In an example of wet on wet printing, the thermally curable ink
composition is printed onto the printed pre-treatment composition
within a period of time ranging from about 0.01 second to about 30
seconds after the printed pre-treatment composition is printed. In
further examples, the thermally curable ink composition is printed
onto the previously applied pre-treatment composition within a
period of time ranging from about 0.1 second to about 20 seconds;
or from about 0.2 second to about 10 seconds; or from about 0.2
second to about 5 seconds after the previously applied composition
is printed. Wet on wet printing may be accomplished in a single
pass.
[0126] In other of these examples, drying takes place after the
application of the pre-treatment composition and before the
application of the thermally curable ink composition. It is to be
understood that in this example, drying of the pre-treatment
composition may be accomplished in any suitable manner, e.g., air
dried (e.g., at a temperature ranging from about 20.degree. C. to
about 80.degree. C. for 30 seconds to 5 minutes), or by exposure to
heat via any suitable heat source (e.g. for 3 seconds or less),
and/or the like.
[0127] In some examples of the method 200, warming or cooling of
the textile fabric may take place before and/or concurrently with
UV and/or IR radiation exposure. As such, some examples of the
method 200 include warming or cooling the fabric substrate having
the thermally curable ink composition thereon at a temperature
below a fixation temperature of the thermally curable ink
composition: i) before the selectively heating; or ii) concurrently
with the selectively heating; or iii) both before and concurrently
with the selectively heating.
[0128] Warming or cooling may be performed as described in
reference to the method 100.
[0129] Referring now to FIGS. 3A and 3B, schematic diagrams of two
different printing systems 10, 10' including inkjet printheads 12,
or 12 and 14, or 12', or 12' and 14' and a narrow wavelength light
source 18 or 18'.
[0130] The example system 10 shown in FIG. 3A illustrates a system
for single pass printing and selective heating, and the example
system 10' shown in FIG. 3B illustrates a system for multiple pass
printing and single or multiple pass selective heating.
[0131] In the example system 10 shown in FIG. 3A, the textile
fabric/fabric substrate 20 may be transported through the printing
system 10 along the path shown by the arrow 22. In this example, a
pagewide printhead 12 (i.e., a series of printheads extending the
width of the fabric substrate 20) is in a fixed position relative
to the fabric substrate 20. When the fabric substrate 20 is moved
relative to the pagewide printhead 12, a single color or multiple
colors of the thermally curable ink composition 24 is/are inkjet
printed directly onto fabric substrate 20 by the pagewide printhead
12 to form an ink layer. The color(s), amount(s), and arrangement
of the thermally curable ink composition(s) 24 that is/are applied
depend upon the digital image from which the print is being
generated. In this example, after the thermally curable ink
composition(s) 24 is/are dispensed, the narrow wavelength light
source 18 is operated to expose the fabric substrate 20 having the
thermally curable ink composition(s) 24 printed thereon to UV
and/or IR radiation 26 for a total exposure time of 3 seconds or
less. UV and/or IR radiation exposure may take place in one light
source on event or in intermittent light source on events (where
the narrow wavelength light source 18 is turned on an off while the
fabric substrate 20 is positioned relative to the narrow wavelength
light source 18. In this single pass printing system 10, printing
and selective heating of the pigment in the printed ink are each
performed as the fabric substrate 20 is within proximity of the
respective printer component.
[0132] As shown in FIG. 3A, some examples of the printing system 10
further include the inkjet printhead 14, which contains and
dispenses the pre-treatment composition 28. In this example, inkjet
printhead 14 is a pagewide printhead that is in a fixed position
relative to the fabric substrate 20. When the fabric substrate 20
is moved relative to the inkjet printhead 14, an example of the
pre-treatment composition 28 disclosed herein is inkjet printed
directly onto fabric substrate 20. The fabric substrate 20 is then
moved to be exposed to printing and selective heating, While not
shown, it is to be understood that the inkjet printhead 14 could be
replaced with a mechanism that will apply the pre-treatment
composition 28 in accordance with an analog method. The mechanism
could be an in-line or off-line sprayer, roll coater, etc. Also
while not shown, a dryer may be positioned between the printheads
14 and 12 to dry the pre-treatment composition before the thermally
curable inkjet ink is applied thereon.
[0133] The single pass printing and selective heating performed
using the printing system 10 results in the printed article 30 on
the fabric substrate 20. The heat absorbed by the pigment is
sufficient to bind the pigment onto the fabric substrate 20. The
heat to initiate fixation may range from about 100.degree. C. to
about 200.degree. C.
[0134] In the example system 10' shown in FIG. 3B, the textile
fabric/fabric substrate 20 may be transported through the printing
system 10' along the path shown by the arrow 22'. In this example,
printhead(s) 12' is attached to a carriage (not shown) or other
mechanism that moves the printhead 12' relative to the fabric
substrate 20 in the path shown by the arrow 32. When the
printhead(s) 12' is/are moved relative to the fabric substrate 20,
a single color or multiple colors of the thermally curable ink
composition 24 is/are inkjet printed directly onto fabric substrate
20 by the printhead(s) 12' to form an ink layer. The color(s),
amount(s), and arrangement of the thermally curable ink
composition(s) 24 that is/are applied depend upon the digital image
from which the print is being generated. In this example, the total
desired amount of thermally curable ink composition(s) 24 that is
dispensed takes place over multiple passes of the printhead(s)
12'.
[0135] Exposure to the UV and/or IR radiation may occur after the
multiple printing passes, or between each of the multiple printing
passes. In this example, the narrow wavelength light source 18' is
attached to a carriage (not shown) or other mechanism that moves
the narrow wavelength light source 18' relative to the fabric
substrate 20 in the path shown by the arrow 32. As discussed in
reference to the methods 100, 200, the total exposure time is 3
seconds or less, whether exposure takes place in a single pass or
multiple passes.
[0136] As shown in FIG. 3B, some examples of the printing system
10' further include the inkjet printhead 14', which contains and
dispenses the pre-treatment composition 28. In this example, inkjet
printhead 14' is a printhead that is attached to a carriage (not
shown) or other mechanism that moves the printhead 14' relative to
the fabric substrate 20 in the path shown by the arrow 32. When the
fabric substrate 20 is moved relative to the inkjet printhead 14',
an example of the pre-treatment composition 28 disclosed herein is
inkjet printed directly onto fabric substrate 20. The printhead 12'
and the narrow wavelength radiation source 18' are then moved to
print and selectively heat. While not shown, it is to be understood
that the inkjet printhead 14' could be replaced with a mechanism
that will apply the pre-treatment composition 28 in accordance with
an analog method. The mechanism could be an in-line or off-line
sprayer, roll coater, etc.
[0137] The multiple pass printing and single or multiple pass
selective heating performed using the printing system 10' results
in the printed article 30 on the fabric substrate 20. The heat
absorbed by the pigment is sufficient to bind the pigment onto the
fabric substrate 20. The heat to initiate fixation may range from
about 100.degree. C. to about 200.degree. C.
[0138] To further illustrate the present disclosure, examples are
given herein. It is to be understood that these examples are
provided for illustrative purposes and are not to be construed as
limiting the scope of the present disclosure.
EXAMPLES
Example 1
[0139] In this example, several example print swaths, comparative
print swaths, and control print swaths were generated.
[0140] The fabric substrates used were cotton and nylon. A
pre-treatment composition, a cyan thermally curable ink, and a
black thermally curable ink were used. The pre-treatment
composition is shown in Table 1 and the cyan and black thermally
curable ink compositions are shown in Table 2.
TABLE-US-00001 TABLE 1 Pre-Treatment Composition Ingredient Wt Type
Specific Ingredient % Solvent Tetraethylene glycol 12 Surfactant
SURFYNOL .RTM. SEF 0.07 (Evonik Ind.) Fixing Agent Calcium nitrate
tetrahydrate 10 Chelating TIRON .TM. monohydrate 0.1 Agent
Antimicrobial ACTICIDE .RTM. B20 0.04 (Thor Chemicals) Water
Balance
TABLE-US-00002 TABLE 2 Thermally Curable Ink Compositions
Ingredient Specific Black Ink Cyan Ink Type Ingredient (wt %) (wt
%) UV absorbing carbon black 2.75 N/A Pigment cyan (PB15:3) N/A 2.5
Dispersion Binder IMPRANIL .RTM. DLN-SD 6 6 Solvent Glycerol 8 8
Surfactant SURYNOL .RTM. 440 0.3 0.3 Anti-Kogation CRODAFOS .TM.
N-3A 0.5 0.5 Agent Anti-Decel Agent LIPONIC .RTM. EG-1 1 1
Antimicrobial ACTICIDE .RTM. B20 0.044 0.044 (Thor Chemicals) Water
Balance Balance
[0141] To prepare the print swaths, 1 drop per pixel of the
pre-treatment composition was printed on the respective fabric
substrates, and 3 drops per pixel of either the black ink or the
cyan ink was printed on the pre-treatment composition. The inks
were printed in two passes -1/2 of the ink in the first pass and
1/2 of the ink in the other pass.
[0142] For some of the example print swaths, a 395 nm light
emitting diode (Hereaus lamp) was used. When operated at 50% power,
the light source emitted 6.62 W/cm.sup.2. The example print swaths
on the cotton fabric were exposed to 6 exposures of 500 msec each,
with a total energy of 19.87 J/cm.sup.2. The example print swaths
on the nylon fabric were exposed to 2 exposures of 100 msec each,
with a total energy of 1.32 J/cm.sup.2. On the nylon fabric, UV
radiation exposure took place after each of the ink passes.
[0143] For some the comparative print swaths, a heat press alone
was used. The comparative print swaths were exposed to 150.degree.
C. for 3 minutes using the heat press.
[0144] For some other comparative print swaths, both LED exposure
and heat press exposure were.
[0145] For the control print swaths, no heating was used. These
print swaths were allowed to air dry.
[0146] After printing and the various drying techniques were
performed, each of the example print swaths, comparative example
print swaths, and the control print swaths was washed 5 times in a
Kenmore 90 Series Washer (Model 110.289 227 91) with warm water (at
about 40.degree. C.) and detergent. Each print was allowed to air
dry between each wash.
[0147] Photographs were taken of the swaths after washing to
visibly compare the washfastness of the control, example, and
comparative examples swaths. The results, which are reproduced in
black and white, are shown in FIGS. 4 through 7. To easily compare
the control, example, and comparative example print swaths, a
control swath was generated next to an example swath, and another
example swath was generated next to a comparative example swath.
Table 3 provides a key for FIGS. 4 and 5, which show the various
swaths printed on cotton. Table 4 provides a key for FIGS. 6 and 7,
which show the various swaths printed on nylon.
TABLE-US-00003 TABLE 3 Cotton Black Ink Cyan Ink FIG. # Control LED
Heat Press Control LED Heat Press 4 C1 E1 and CE2 and N/A N/A N/A
CE2 CE1 5 N/A N/A N/A C2 E2 and CE4 and CE4 CE3
TABLE-US-00004 TABLE 4 Nylon Black Ink Cyan Ink FIG. # Control LED
Heat Press Control LED Heat Press 6 C3 E3 and CE6 and N/A N/A N/A
CE6 CE5 7 N/A N/A N/A C4 E4 and CE8 and CE8 CE7
[0148] As depicted in FIG. 4, the black example print swath E1
printed on cotton and exposed to LED heating exhibited much better
washfastness than the control black C1, and exhibited slightly
better washfastness than the black comparative example print swath
CE1 printed on cotton and exposed to the heat press and the black
comparative example print swath CE2 printed on cotton and exposed
to both LED and the heat press.
[0149] As depicted in FIG. 5, the cyan example print swath E2
printed on cotton and exposed to LED heating exhibited much better
washfastness than the control cyan C2, and exhibited slightly
better washfastness than the cyan comparative example print swath
CE3 printed on cotton and exposed to the heat press and the cyan
comparative example print swath CE4 printed on cotton and exposed
to both LED and the heat press.
[0150] As depicted in FIG. 6, the black example print swath E3
printed on nylon and exposed to LED heating exhibited much better
washfastness than the control black C3, and exhibited comparable or
slightly better washfastness than the black comparative example
print swath CE5 printed on nylon and exposed to the heat press and
the black comparative example print swath CE6 printed on nylon and
exposed to both LED and the heat press.
[0151] As depicted in FIG. 7, the cyan example print swath E4
printed on nylon and exposed to LED heating exhibited much better
washfastness than the control cyan C4, and exhibited comparable or
slightly better washfastness than the cyan comparative example
print swath CE7 printed on nylon and exposed to the heat press and
the cyan comparative example print swath CE8 printed on nylon and
exposed to both LED and the heat press.
[0152] After printing, the initial optical density of each example
swath, control swath and comparative swath exposed to the heat
press alone was measured. The optical density of each print swath
was again measured after washing. The change in optical density
(.DELTA. OD) was calculated for each print swath. The results are
shown in FIG. 8. The change in optical density was less for each of
the example swaths (E1-E4), which confirms the conclusions made
based on the photographs.
[0153] Overall, the results in this example illustrate that LED
exposure forms prints with improved washfastness on both cotton and
nylon, when compared to prints formed with no heating or with heat
press heating. LED exposure also speeds up the printing process,
comparing. e.g., 3 minutes with the heat press versus 0.2 seconds
or 3 seconds with the LED lamp.
Example 2
[0154] Twelve examples of the thermally curable ink composition
disclosed herein were prepared.
[0155] The example binder included in four of the example ink
compositions (referred to as "example 1 black," "example 1 cyan,"
"example 1 magenta," and "example 1 yellow") was IMPRANIL.RTM.
DLN-SD (an anionic aliphatic polyester-polyurethane binder, CAS
#375390-41-3; Mw 45,000 Mw; Acid Number 5.2; Tg -47.degree. C.;
Melting Point 175-200.degree. C.) from Covestro. The general
formulation of these four example ink compositions is shown in
Table 4, with the wt % active of each component that was used. For
example, the weight percentage of the pigment dispersion represents
the total pigment solids (i.e., wt % active pigment) present in the
final ink formulations. In other words, the amount of the pigment
dispersion added to the example ink compositions was enough to
achieve a pigment solids level equal to the given weight percent.
Similarly, the weight percentage of the binder represents the total
binder solids (i.e., wt % active binder) present in the final ink
formulations. Additionally, a 5 wt % potassium hydroxide aqueous
solution was added to each of the example ink compositions until a
pH of about 8.5 was achieved.
TABLE-US-00005 TABLE 5 Example Example Example Example 1 1 1 1
Specific black cyan magenta yellow Ingredient Component (wt %) (wt
%) (wt %) (wt %) Pigment Black 2.5 -- -- -- dispersion pigment
dispersion Cyan -- 2.5 -- -- pigment dispersion Magenta -- -- 3 --
pigment dispersion Yellow -- -- -- 3 pigment dispersion Binder
IMPRANIL .RTM. 6 6 6 6 DLN-SD Co-solvent Glycerol 8 8 8 8
Anti-decel LIPONIC .RTM. 1 1 1 1 agent EG-1 Anti- CRODAFOS .TM. 0.5
0.5 0.5 0.5 kogation N-3A agent Surfactant SURFYNOL .RTM. 0.3 0.3
0.3 0.3 440 Biocide ACTICIDE .RTM. 0.044 0.044 0.044 0.044 B20
Water Deionized Balance Balance Balance Balance water
[0156] The example binder included in another four of the example
ink compositions (referred to as "example 2 black," "example 2
cyan," "example 2 magenta," and "example 2 yellow") was a latex
polymer binder. The general formulation of these four example ink
compositions is shown in Table 6, with the wt % active of each
component that was used.
TABLE-US-00006 TABLE 6 Example Example Example Example 2 2 2 2
Specific black cyan magenta yellow Ingredient Component (wt %) (wt
%) (wt %) (wt %) Pigment Black ~2 -- -- -- dispersion pigment
dispersion Cyan -- ~1.5 -- -- pigment dispersion Magenta -- -- ~3
-- pigment dispersion Yellow -- -- -- ~3 pigment dispersion Binder
Latex polymer 7 7 7 7 Co- 2-pyrrolidone 13 13 13 13 solvent
2-methyl-1,3- 9 9 9 9 propanediol Chelating TRILON .RTM. 0.04 0.04
0.04 0.04 agent M Anti- CRODAFOS .TM. 0.2 0.2 0.2 0.2 kogation N-3A
agent Surfactant TERGITOL .RTM. 0.5 0.5 0.5 0.5 15-S-7 TERGITOL
.RTM. 0.9 0.9 0.9 0.9 TMN-6 CAPSTONE .RTM. 0.65 0.65 0.65 0.65
FS-35 Wax Filled wax 0.8 0.8 0.8 0.8 Biocide ACTICIDE .RTM. 0.04
0.04 0.04 0.04 B20 Water Deionized Balance Balance Balance Balance
water
[0157] The example binder included in the last four of the example
ink compositions (referred to as "example 3 black," "example 3
cyan," "example 3 magenta," and "example 3 yellow") was another
type of latex polymer binder. The general formulation of these four
example ink compositions is shown in Table 7, with the wt % active
of each component that was used.
TABLE-US-00007 TABLE 7 Example Example Example Example 3 3 3 3
Specific black cyan magenta yellow Ingredient Component (wt %) (wt
%) (wt %) (wt %) Pigment Black ~2.5 -- -- -- dispersion pigment
dispersion Cyan -- ~1.5 -- -- pigment dispersion Magenta -- -- ~3.5
-- pigment dispersion Yellow -- -- -- ~3.5 pigment dispersion
Binder Latex polymer 10 10 10 10 Co- 1,2-butanediol 18 18 18 18
solvent 2-pyrrolidone 3 3 3 3 Tripropylene 2 2 2 2 glycol methyl
ether Anti- CRODAFOS .TM. 0.35 0.35 0.35 0.35 kogation O3A agent
Surfactant TERGITOL .RTM. 0.2 0.2 0.2 0.2 15-S-7 CAPSTONE .RTM. 0.4
0.4 0.4 0.4 FS-35 Water Deionized Balance Balance Balance Balance
water
[0158] Several prints were generated by thermal inkjet printing
using the example ink compositions. For each print, the amount of
the example ink composition printed was 20 gsm. The prints were
generated on cotton. No pre-treatment was performed on the fabric
before generating the prints.
[0159] The post-treatment that was performed on each region of a
first set of prints is schematically shown in FIG. 9. For these
prints, there were two control regions and an example region. In
the control regions (at the left and right of each print), no
post-treatment or curing was performed (this region is labeled
"untreated control" in FIGS. 9-12 and Tables 8 and 9). In the
example region (at the middle of each print), the print was exposed
to ultraviolet light for 1 second from a 395 nm light emitting
diode operated at 50% energy (this region is labeled "LED exposed"
in FIG. 9 and Tables 8 and 9 and "LED395, 50% energy, 1 sec" in
FIGS. 10A, 11A, and 12A). When operated at 50% power, the light
source emitted 6.62 W/cm.sup.2. The post-treatment that was
performed on a second set of prints involved exposure to the heat
press at 150.degree. C. for about 3 minutes.
[0160] Optical Density
[0161] The initial optical density (initial OD) of each region of
each print in the first set of prints was measured. The initial
optical density (initial OD) of each print in the second set of
prints was also measured. Then, the prints in each set were washed
5 times in a Kenmore 90 Series Washer (Model 110.289 227 91) with
warm water (at about 40.degree. C.) and detergent. Each print was
allowed to air dry between each wash. Then, the optical density (OD
after 5 washes) of each region of each print in the first set of
prints and of each print in the second set of prints was measured,
and the percent change in optical density (%.DELTA. OD) was
calculated for each region and print.
[0162] The initial optical density (initial OD), the optical
density after 5 washes (OD after 5 washes), and the percent change
in optical density (%.DELTA. in OD) of each region and print are
shown in Table 8. In Table 8, each region or print is identified by
the example ink composition, and the post-treatment (if any) used
to generate the region or print.
TABLE-US-00008 TABLE 8 (Cotton) Post-treatment used to generate Ink
composition used the region/ Initial OD after % .DELTA. to generate
the print print OD 5 washes in OD Example 1 black Untreated control
1.121 0.798 -28.8 Example 1 cyan Untreated control 1.053 0.777
-26.2 Example 1 magenta Untreated control 1.010 0.679 -32.8 Example
1 yellow Untreated control 1.092 0.645 -41.0 Example 2 black
Untreated control 1.053 0.442 -58.1 Example 2 cyan Untreated
control 0.959 0.177 -81.6 Example 2 magenta Untreated control 0.953
0.263 -72.5 Example 2 yellow Untreated control 0.931 0.115 -87.6
Example 3 black Untreated control 1.156 0.559 -51.7 Example 3 cyan
Untreated control 1.034 0.359 -65.3 Example 3 magenta Untreated
control 1.040 0.382 -63.3 Example 3 yellow Untreated control 0.988
0.339 -65.7 Example 1 black LED exposed 1.159 1.080 -6.8 Example 1
cyan LED exposed 1.072 0.897 -16.4 Example 1 magenta LED exposed
1.044 0.874 -16.3 Example 1 yellow LED exposed 1.001 0.834 -16.6
Example 2 black LED exposed 1.125 1.029 -8.5 Example 2 cyan LED
exposed 1.035 0.913 -11.8 Example 2 magenta LED exposed 0.996 0.871
-12.6 Example 2 yellow LED exposed 1.017 0.898 -11.7 Example 3
black LED exposed 1.194 1.035 -13.3 Example 3 cyan LED exposed
1.062 0.880 -17.1 Example 3 magenta LED exposed 1.097 0.949 -13.5
Example 3 yellow LED exposed 1.089 0.930 -14.6 Example 1 black Heat
press 1.153 1.008 -12.6 Example 1 cyan Heat press 1.104 1.013 -8.3
Example 1 magenta Heat press 0.977 0.898 -8.1 Example 1 yellow Heat
press 1.025 0.902 -12.0 Example 2 black Heat press 1.070 0.864
-19.2 Example 2 cyan Heat press 0.998 0.812 -18.6 Example 2 magenta
Heat press 0.956 0.782 -18.2 Example 2 yellow Heat press 0.965
0.778 -19.3 Example 3 black Heat press 1.107 0.870 -21.5 Example 3
cyan Heat press 1.005 0.799 -20.5 Example 3 magenta Heat press
1.053 0.783 -25.7 Example 3 yellow Heat press 1.023 0.688 -32.8
[0163] As shown in Table 8, the regions of the prints in the first
set of prints exposed to ultraviolet light had a change in optical
density of at least 37% less than the change in optical density of
the regions of the same print that was untreated (i.e., the
control). These results indicate that the prints generated on
cotton with an example ink composition and exposed to 395 nm
ultraviolet light from an LED for 1 second have higher optical
density than prints generated on cotton with the example ink
composition and without any post-treatment.
[0164] As also shown in Table 8, for the prints generated with the
"example 2" ink compositions, the regions of the prints exposed to
ultraviolet light had a change in optical density of at least 30%
less than the change in optical density of the same color prints
that were exposed to the heat press at 150.degree. C. for 3
minutes. Table 8 further shows, for the prints generated with the
"example 3" ink compositions, that the regions of the prints
exposed to ultraviolet light had a change in optical density of at
least 16.5% less than the change in optical density of the same
color prints that were exposed to the heat press at 150.degree. C.
for 3 minutes. These results indicate that the prints generated on
cotton with an "example 2" ink composition or "example 3" ink
composition and exposed to 395 nm ultraviolet light from an LED for
1 second have higher optical density than prints generated on
cotton with an "example 2" ink composition or "example 3" ink
composition and exposed to a heat press at 150.degree. C. for 3
minutes.
[0165] Washfastness
[0166] The prints were also tested for washfastness. The L*a*b*
values of a color (e.g., cyan, magenta, yellow, black, red, green,
blue, white) before and after the 5 washes were measured. L* is
lightness, a* is the color channel for color opponents green-red,
and b* is the color channel for color opponents blue-yellow. The
color change was then calculated using both the CIEDE1976
color-difference formula and the CIEDE2000 color-difference
formula.
[0167] The CIEDE1976 color-difference formula is based on the
CIELAB color space. Given a pair of color values in CIELAB space
L*.sub.1,a*.sub.1,b*.sub.1 and L*.sub.2,a*.sub.2,b*.sub.2, the
CIEDE1976 color difference between them is as follows:
.DELTA.E.sub.76= {square root over
([(L*.sub.2-L*.sub.1).sup.2+(a*.sub.2-a*.sub.1).sup.2+(b*.sub.2-b*.sub.1)-
.sup.2])}
[0168] It is noted that .DELTA.E.sub.76 is the commonly accepted
notation for CIEDE1976.
[0169] The CIEDE2000 color-difference formula is based on the
CIELAB color space. Given a pair of color values in CIELAB space
L*.sub.1,a*.sub.1,b*.sub.1 and L*.sub.2,a*.sub.2,b*.sub.2, the
CIEDE2000 color difference between them is as follows:
.DELTA.E.sub.00(L*.sub.1,a*.sub.1,b*.sub.1;
L*.sub.2,a*.sub.2,b*.sub.2)=.DELTA.E.sub.00.sup.12=.DELTA.E.sub.00
(1)
It is noted that .DELTA.E.sub.00 is the commonly accepted notation
for CIEDE2000.
[0170] Given two CIELAB color values
{L*.sub.i,a*.sub.i,b*.sub.i}.sub.i=1.sup.2 and parametric weighting
factors k.sub.L, k.sub.C, k.sub.H, the process of computation of
the color difference is summarized in the following equations,
grouped as three main parts.
[0171] 1. Calculate C'.sub.i,h'.sub.i:
C i , ab * .times. ( ( a i * ) 2 + ( b i * ) 2 ) , .times. i = 1 ,
2 ( 2 ) C _ ab * = C 1 , ab * + C 2 , ab * 2 ( 3 ) G = 0.5 .times.
( 1 - ( C _ ab * 7 C _ ab * 7 + 25 7 ) ) ( 4 ) a i ' = ( 1 + G )
.times. a i * , i = 1 , 2 ( 5 ) C i ' = ( ( a i ' ) 2 + ( b i ' ) 2
) , .times. i = 1 , 2 ( 6 ) h i ' = { 0 b i * = a i ' = 0 tan - 1
.function. ( b i * , a i ' ) otherwise , i = 1 , 2 ( 7 )
##EQU00001##
[0172] 2. Calculate .DELTA.L', .DELTA.C',.DELTA.H':
.DELTA. .times. .times. L ' = L 2 * - L 1 * ( 8 ) .DELTA. .times.
.times. C ' = C 2 * - C 1 * ( 9 ) .DELTA. .times. .times. h ' = { 0
C 1 ' .times. C 2 ' = 0 h 2 ' - h 1 ' C 1 ' .times. C 2 ' .noteq. 0
; h 2 ' - h 1 ' .ltoreq. 180 .smallcircle. ( h 2 ' - h 1 ' ) - 360
C 1 ' .times. C 2 ' .noteq. 0 ; h 2 ' - h 1 ' > 180
.smallcircle. ( h 2 ' - h 1 ' ) + 360 C 1 ' .times. C 2 ' .noteq. 0
; h 2 ' - h 1 ' < `180 .smallcircle. ( 10 ) .DELTA. .times.
.times. H ' = 2 .times. C 1 ' .times. C 2 ' .times. sin .function.
( .DELTA. .times. .times. h ' 2 ) ( 11 ) ##EQU00002##
[0173] 3. Calculate CIEDE2000 color-difference .DELTA.E.sub.00:
.times. L _ ' = ( L 1 * + L 2 * ) / 2 ( 12 ) .times. C _ ' = ( C 1
* + C 2 * ) / 2 ( 13 ) h _ ' = { h 1 ' + h 2 ' 2 h 1 ' - h 2 '
.ltoreq. 180 .smallcircle. ; C 1 ' .times. C 2 ' .noteq. 0 h 1 ' +
h 2 ' + 360 .smallcircle. 2 h 1 ' - h 2 ' > 180 .smallcircle. ;
( h 1 ' + h 2 ' ) < 360 .smallcircle. ; C 1 ' .times. C 2 '
.noteq. 0 h 1 ' + h 2 ' - 360 .smallcircle. 2 h 1 ' - h 2 ' >
180 .smallcircle. ; ( h 1 ' + h 2 ' ) .gtoreq. 360 .smallcircle. ;
C 1 ' .times. C 2 ' .noteq. 0 ( h 1 ' + h 2 ' ) C 1 ' .times. C 2 '
= 0 ( 14 ) T = 1 - 0.17 .times. cos .function. ( h _ ' - 30
.smallcircle. ) + 0.24 .times. cos .function. ( 2 .times. h _ ' ) +
0.32 .times. cos .function. ( 3 .times. h _ ' + 6 .smallcircle. ) -
0.20 .times. cos .function. ( 4 .times. h _ ' - 63 .smallcircle. )
( 15 ) .times. .DELTA..theta. = 30 .times. exp .times. { - [ h _ '
- 275 .smallcircle. 25 ] 2 } ( 16 ) .times. R c = 2 .times. ( C _
'7 C _ '7 + 25 7 ) ( 17 ) .times. S L = 1 + 0.015 .times. ( L _ ' -
50 ) 2 ( 20 + ( L _ ' - 50 ) 2 ) ( 18 ) .times. S C = 1 + 0.045
.times. C _ ' ( 19 ) .times. S H = 1 + 0.015 .times. C _ ' .times.
T ( 20 ) .times. R T = - sin .function. ( 2 .times. .DELTA..theta.
) .times. R C ( 21 ) .DELTA. .times. .times. E 00 12 = .DELTA.
.times. .times. E 00 .function. ( L 1 * , a 1 * , b 1 * ; L 2 * ; L
2 * , a 2 * , b 2 * ) = ( ( .DELTA. .times. .times. L ' k L .times.
S L ) 2 + ( .DELTA. .times. .times. C ' k C .times. S C ) 2 + (
.DELTA. .times. .times. H ' k H .times. S H ) 2 + R T .function. (
.DELTA. .times. .times. C ' k C .times. S C ) .times. ( .DELTA.
.times. .times. H ' k H .times. S H ) ) ( 22 ) ##EQU00003##
[0174] The results of the .DELTA.E.sub.76 calculations and the
.DELTA.E.sub.00 calculations for each region of each print
generated are shown in Table 9. In Table 9, each region or print is
identified by the example ink composition, and the post-treatment
(if any) used to generate the region or print.
TABLE-US-00009 TABLE 9 (Cotton) Ink composition used Post-treatment
used to generate the print to generate the print .DELTA.E.sub.76
.DELTA.E.sub.00 Example 1 black Untreated control 13.59 11.88
Example 1 cyan Untreated control 10.98 7.16 Example 1 magenta
Untreated control 14.40 7.49 Example 1 yellow Untreated control
26.60 6.18 Example 2 black Untreated control 31.30 31.10 Example 2
cyan Untreated control 46.10 28.26 Example 2 magenta Untreated
control 45.68 27.06 Example 2 yellow Untreated control 62.60 22.74
Example 3 black Untreated control 28.80 27.67 Example 3 cyan
Untreated control 32.15 20.88 Example 3 magenta Untreated control
35.70 21.68 Example 3 yellow Untreated control 43.64 13.53 Example
1 black LED exposed 3.44 2.95 Example 1 cyan LED exposed 6.13 3.97
Example 1 magenta LED exposed 6.97 3.29 Example 1 yellow LED
exposed 4.96 1.18 Example 2 black LED exposed 4.43 3.89 Example 2
cyan LED exposed 6.60 4.35 Example 2 magenta LED exposed 6.45 4.80
Example 2 yellow LED exposed 3.81 2.27 Example 3 black LED exposed
6.38 5.40 Example 3 cyan LED exposed 7.16 5.43 Example 3 magenta
LED exposed 7.08 4.95 Example 3 yellow LED exposed 5.13 2.22
Example 1 black Heat press 6.05 5.09 Example 1 cyan Heat press 3.78
2.50 Example 1 magenta Heat press 4.10 1.74 Example 1 yellow Heat
press 8.26 1.83 Example 2 black Heat press 9.06 7.95 Example 2 cyan
Heat press 6.24 4.77 Example 2 magenta Heat press 8.79 4.64 Example
2 yellow Heat press 10.45 2.65 Example 3 black Heat press 11.17
9.70 Example 3 cyan Heat press 6.45 4.76 Example 3 magenta Heat
press 13.21 7.43 Example 3 yellow Heat press 18.39 4.57
[0175] As shown in Table 9, the .DELTA.E.sub.76 value and the
.DELTA.E.sub.00 value of the regions of the prints exposed to
ultraviolet light were at least 44% less than, respectively, the
.DELTA.E.sub.76 value and the .DELTA.E.sub.00 value of the region
of the same print that was untreated (i.e., the control prints).
These results indicate that the prints generated on cotton with an
example ink composition and exposed to 395 nm ultraviolet light
with an LED for 1 second have better washfastness than prints
generated on cotton with the example ink compositions without any
post-treatment.
[0176] As also shown in Table 9, for the prints generated with the
"example 2" ink compositions, the .DELTA.E.sub.76 value of the
regions of the prints exposed to ultraviolet light were at least
26% less than the .DELTA.E.sub.76 value of the same color print
that was exposed to the heat press at 150.degree. C. for 3 minutes.
Table 9 further shows, for the prints generated with the "example
2" ink compositions, the .DELTA.E.sub.00 value of the regions of
the prints exposed to ultraviolet light were less than or
comparable to the .DELTA.E.sub.00 value of the region of the same
color print that was exposed to the heat press at 150.degree. C.
for 3 minutes. Still further, Table 9 shows, for the prints
generated with the "example 3" ink compositions, the
.DELTA.E.sub.76 value and the .DELTA.E.sub.00 value of the regions
of the prints exposed to ultraviolet light were less than or
comparable to, respectively, the .DELTA.E.sub.76 value and the
.DELTA.E.sub.00 value of the same color print that was exposed to
the heat press at 150.degree. C. for 3 minutes. These results
indicate that the prints generated on cotton with an "example 2"
ink composition or "example 3" ink composition and exposed to 395
nm ultraviolet light from an LED for 1 second have better
washfastness than prints generated on cotton with an "example 2"
ink composition or "example 3" ink composition and exposed to the
heat press at 150.degree. C. for 3 minutes.
[0177] Color photographs of each of the prints generated in this
example were taken before and after washing. The before and after
photographs for the prints with the untreated control and example
regions are reproduced in black and white in FIGS. 10A, 11A, and
12A, and the before and after photographs for the comparative
prints exposed to the heat press are reproduced in black and white
in FIGS. 10B, 11B, and 12B. Specifically, FIGS. 10A and 10B show
the prints formed with the example 1 inks, FIGS. 11A and 11B show
the prints formed with the example 2 inks, and FIGS. 12A and 12B
show the prints formed with the example 3 inks. The labeling in
FIGS. 10A, 11A, and 12A follows the schematic in FIG. 9. These
results clearly that the regions of the prints exposed to 395 nm
ultraviolet light exhibit better or comparable washfastness than
the untreated control regions.
[0178] It is to be understood that the ranges provided herein
include the stated range and any value or sub-range within the
stated range, as if such values or sub-ranges were explicitly
recited. For example, from about 2 wt % to about 15 wt % should be
interpreted to include not only the explicitly recited limits of
from about 2 wt % to about 15 wt %, but also to include individual
values, such as about 2.35 wt %, about 3.5 wt %, about 10 wt %,
about 13.5 wt %, etc., and sub-ranges, such as from about 2.5 wt %
to about 14 wt %, from about 4.5 wt % to about 12.5 wt %, etc.
Furthermore, when "about" is utilized to describe a value, this is
meant to encompass minor variations (up to +/-10%) from the stated
value.
[0179] Reference throughout the specification to "one example",
"another example", "an example", and so forth, means that a
particular element (e.g., feature, structure, and/or
characteristic) described in connection with the example is
included in at least one example described herein, and may or may
not be present in other examples. In addition, it is to be
understood that the described elements for any example may be
combined in any suitable manner in the various examples unless the
context clearly dictates otherwise.
[0180] In describing and claiming the examples disclosed herein,
the singular forms "a", "an", and "the" include plural referents
unless the context clearly dictates otherwise.
[0181] While several examples have been described in detail, it is
to be understood that the disclosed examples may be modified.
Therefore, the foregoing description is to be considered
non-limiting.
* * * * *