(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`(19) World Intellectual Property Organization
`International Bureau
`
`10 March 2011 (10.03.2011) (10) International Publication Number
`
`(43) International Publication Date
`
`W0 201 1/028201 A1
`
`
`(51)
`
`(21)
`
`(22)
`
`(25)
`
`(26)
`
`(71)
`
`(72)
`(75)
`
`(74)
`
`International Patent Classification:
`C09D 11/00 (2006.01)
`B4IM 5/26 (2006.01)
`B41J2/01 (2006.01)
`B41M5/385 (2006.01)
`
`(81)
`
`International Application Number:
`PCT/US2009/055904
`
`International Filing Date:
`3 September 2009 (03.09.2009)
`
`Filing Language:
`
`Publication Language:
`
`English
`
`English
`
`except US):
`(for all designated States
`Applicant
`HEWLETT-PACKARD DEVELOPMENT COMPA-
`NY, L.P. [US/US]; 11445 Compaq Center Drive West,
`Houston, Texas 77707 (US).
`
`Inventors; and
`Inventors/Applicants (for US only): GANAPATHIAP-
`PAN, Sivapackia [US/US]; 1501 Page Mill Rd., Palo
`Alto, California 94304-1100 (US). TOM, Howard S.
`[US/US]; 1501 Page Mill Rd., Palo Alto, California
`94304-1100 (US). NG, Hou T. [SG/US]; 1501 Page Mill
`Rd., Palo Alto, California 94304-1 100 (US).
`
`Agents: COLLINS, David W. et al.; Hewlett-Packard
`Company, Intellectual Propery Administration, 3404 E.
`Harmony Road, Mail Stop 35, Fort Collins, Colorado
`80528 (US).
`
`Designated States (unless otherwise indicated, for every
`kind ofnational protection available): AE, AG, AL, AM,
`AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ,
`CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO,
`DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,
`HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP,
`KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD,
`ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,
`NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD,
`SE, SG, SK, SL, SM, ST, SV, SY, TJ, TM, TN, TR, TT,
`TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.
`
`(84)
`
`Designated States (unless otherwise indicated, for every
`kind of regional protection available): ARIPO (BW, GH,
`GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
`ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ,
`TM), European (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
`ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV,
`MC, MK, MT, NL, NO, PL, PT, RO, SE, SI, SK, SM,
`TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW,
`ML, MR, NE, SN, TD, TG).
`Declarations under Rule 4.17:
`
`as to the identity ofthe inventor (Rule 4.17(i))
`
`as to applicant’s entitlement to apply for and be granted
`a patent (Rule 4.l7(ii))
`Published:
`
`with international search report (Art. 21(3))
`
`(54) Title: INK-JET INK PRINTING SYSTEM AND METHOD
`
`(57) Abstract: An ink-jet ink printing method and associated system can comprise a printer including an ink-jet ink. The ink com-
`prises an aqueous liquid vehicle, 1 Wt % t0 5 Wt % pigment, 1 Wt % t0 5 Wt % acrylic polymer particles, 0.3 Wt % t0 3 Wt % ure—
`thane polymer particles, and is formulated to print on a Vinyl medium. The system also includes a heating device. Upon applying
`heat to the ink—jet ink printed on the vinyl medium, the polymer particles in the printed ink fuse, and form a film encapsulating at
`least a portion of the pigment on the vinyl print medium.
`
`
`
`W02011/028201A1|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`INK-JET INK PRINTING SYSTEM AND METHOD
`
`BACKGROUND
`
`1O
`
`15
`
`20
`
`25
`
`Polymers are often used to improve the durability of prints using a variety of
`
`printing techniques. One example is the dry toner used in the commercial printers. These
`
`include polymers that are insoluble in water and typically do not include surface groups
`
`for stabilization for printability. Usage of such polymers is therefore difficult in water—
`
`based ink—jet inks. To overcome this problem, latex polymers are sometimes used since
`
`such polymers show low viscosity with higher amount of solid contents. However, the
`
`final print durability is typically not as good compared to electrophotography—based (i.e.
`
`laser—based) print. In some cases, chemical fixers are used to improve waterfastness.
`
`However, such a system often does not show the desired improvement in terms of rub
`
`resistance. Therefore, new polymeric materials or additives are needed to achieve more
`
`durable print performance with water—based ink—j et printing applications, particularly on
`
`nonporous media.
`
`DETAILED DESCRIPTION
`
`Bcforc thc prcscnt invention is discloscd and dcscribcd, it is to bc undcrstood that
`
`this disclosure is not limited to the particular process steps and materials disclosed herein
`
`because such process steps and materials may vary somewhat. It is also to be understood
`
`that the terminology used herein is used for the purpose of describing particular
`
`embodiments only. The terms are not intended to be limiting because the scope of the
`
`prcscnt disclosure is intcndcd to bc limitcd only by thc appcndcd claims and cquivalcnts
`
`thereof.
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`It is to be noted that, as used in this specification and the appended claims, the
`77 “
`
`singular forms ”a,
`
`an,” and “the” include plural referents unless the context clearly
`
`dictates otherwise.
`
`As used herein, “liquid vehicle,” “vehicle,” or “liquid medium” refers to the fluid
`
`in which the colorant of the present disclosure can be dispersed or dissolved to form an
`
`ink—jet ink. Liquid vehicles are well known in the art, and a wide variety of ink vehicles
`
`may be used in accordance with embodiments of the present disclosure. Such ink
`
`vehicles may include a mixture of a variety of different agents, including without
`
`limitation, surfactants, organic solvents and co—solvents, buffers, biocides, viscosity
`
`modifiers, sequestering agents, stabilizing agents, anti—kogation agents, and water.
`
`Though not part of the liquid vehicle per se, in addition to the colorants, the liquid vehicle
`
`can carry solid additives such as polymers, latexes, UV curable materials, plasticizers,
`
`salts, etc. Additionally, the term “aqueous liquid vehicle” or “aqueous vehicle” refers to a
`
`liquid vehicle including water as a solvent. This refers in particular to liquid vehicles that
`
`are predominantly water, that is, in which water is present in an amount greater than any
`
`other individual liquid component.
`
`As used herein, “liquid vehicle component” refers to any solvent, surfactant,
`
`and/or any other liquid present in a liquid vehicle.
`
`As used herein, “colorant” can include dyes, pigments, and/or other particulates
`
`that may be suspended or dissolved in a liquid vehicle prepared in accordance with
`
`embodiments of the present disclosure. Dyes are typically water soluble, and therefore,
`
`can be desirable for use in some embodiments. However, pigments can also be used in
`
`other embodiments. Pigments that can be used include self—dispersed pigments and
`
`standard pigments that are dispersed by a separate dispersing agent, e. g., polymer
`
`dispersed. Self—dispersed pigments include those that have been chemically surface
`
`modified with a small molecule, a polymeric grouping, or a charge. This chemical
`
`modification aids the pigment in becoming and/or substantially remaining dispersed in a
`
`liquid vehicle. The pigment can also be dispersed by a separate additive, e. g. a polymer,
`
`an oligomer, or a surfactant, in the liquid vehicle and/or in the pigment that utilizes a
`
`physical coating to aid the pigment in becoming and/or substantially remaining dispersed
`
`in a liquid vehicle.
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`As used herein, “pigment” generally includes pigment colorants, magnetic
`
`particles, aluminas, silicas, and/or other ceramics, organo—metallics or other opaque
`
`particles, whether or not such particulates impart color. Thus, though the present
`
`description primarily exemplifies the use of pigment colorants, the term “pigment” can be
`
`used more generally to describe not only pigment colorants, but other pigments such as
`
`organometallics, ferrites, ceramics, etc.
`
`In one specific embodiment, however, the
`
`pigment is a pigment colorant.
`
`As used herein, “dye” refers to the individual compound, complex, or molecule
`
`responsible for an ink’s color, and is typically water soluble.
`
`As used herein, Tg is the glass transition temperature as calculated by the Fox
`
`equation: copolymer Tg : l / (Wa/( Tg A) + Wb(Tg B) + ...) where Wa : weight fraction
`
`of monomer A in the copolymer and TgA is the homopolymer Tg value of monomer A,
`
`Wb = weight fraction of monomer B and TgB is the homopolymer Tg value of monomer
`
`B, etc.
`
`As used herein, the terms “rubfastness” and “smearfastnes s” each refer to the
`
`resistance of a printed ink image to removal by rubbing with a solid object. One type of
`
`smear fastness of interest in the ink—jet printing art is resistance to rubbing with the tip of
`
`a highlighter. Another type of disruption due to rubbing can include actual removal of the
`
`printed ink from the media surface. For example, dry rubbing and/or rubbing using
`
`ammonia cleaning solvent (Windex®) for ink printed on vinyl media is another example
`
`of determining rubfastness. Poor rubfastness results from insufficient adherence of the
`
`ink to the media surface or absorbance of the ink into the surface, as well as insufficient
`
`shcar rcsistancc within thc printcd ink.
`
`As used herein, the term “waterfastness” refers to the resistance of a printed ink
`
`image to dilution or removal by exposure to water. Waterfastness can be measured by
`
`wetting printed ink with water or an aqueous solution and determining any change in
`
`optical density of the printed ink.
`
`thn cvaluating “rubfastncss” or “watcrfastncss” of an imagc printcd in
`
`accordance with the system and/or method of the present disclosure, “increased” or
`
`“improved” rubfastness can be determined by comparing the printed image with a
`
`comparative printed image. The comparative printed image can be prepared identically to
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`the printed image except that the polymer particles used to generate the comparative
`
`printed image do not comprise the mixture of acrylic and urethane described herein. In a
`
`more particular example, acrylic particles having the same monomer content in both inks,
`
`with the difference being that the comparative ink does not include urethane polymers.
`
`No other Changes to the printing and fusing conditions are carried out.
`
`The term “non—porous” when referring media refers to print media which has a
`
`Bristow Test of less than 2 ml/m2 at a contact time of less than 0.5 s. The Bristow Test is
`
`known in the art and is summarized below. A test specimen of defined dimensions is
`
`affixed to the smooth rim of a wheel free to rotate at a defined constant speed in contact
`
`with a stationary test fluid applicator pressing against the test specimen with a defined
`
`pressure. The test fluid applicator consists of a test solution storage compartment affixed
`
`above a 1 mm by 15 mm test fluid delivery slot, the slot being positioned so that the long
`
`dimension is perpendicular to the direction of rotation of the rim of the wheel, and
`
`parallel to the wheel axis. A defined quantity of test fluid is placed through the fluid
`
`reservoir, onto the fluid delivery slot. With the wheel with the test specimen affixed
`
`thereto rotating at constant speed, the test solution applicator is brought into contact with
`
`the rotating test specimen and held in place under defined pressure. The test fluid is
`
`transferred from the test solution applicator onto the test specimen in a band whose width
`
`(controlled by the applicator slot width) is approximately 15 mm, and whose length is
`
`function of the absorptive characteristics of the test fluid interaction with the test
`
`specimen under the defined test conditions. The amount of liquid absorbed per unit area
`
`of test specimen is calculated from the volume of test fluid originally placed in the
`
`applicator, and the average width and length of the band created on the test specimen by
`
`the transferred test fluid. The time available for the liquid absorption is calculated from
`
`the volume of test fluid originally placed in the applicator and applicator geometry.
`
`It is
`
`noted that the printed images prepared using the systems and methods of the present
`
`disclosure are effective for both porous vinyl media and non—porous vinyl media, though
`
`it has typically been more difficult to print aqueous inks with acccptablc rubfastncss on
`
`non—porous vinyl media. This is a problem that is solved in particular in accordance with
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`embodiments of the present disclosure.
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`As used herein, the term “urethane linkage” refers to any compound having the
`
`following structure:
`
`0
`R1\ AL /R2
`N
`O
`H
`
`where R1 and R2 can represent any organic compound. Thus, a “urethane” or
`
`“polyurethane” includes polymers that have urethane linkages, including polymers not
`
`formed by traditional isocyanate and alcohols. When describing monomers, “urethane”
`
`indicates that the monomer has a urethane linkage.
`
`As used herein, the term “about” is used to provide flexibility to a numerical range
`
`endpoint by providing that a given value may be “a little above” or “a little below” the
`
`endpoint. The degree of flexibility of this term can be dictated by the particular variable
`
`and would be within the knowledge of those skilled in the art to determine based on
`
`experience and the associated description herein.
`
`As used herein, the term “substantially” refers to the complete or nearly complete
`
`extent or degree of an action, characteristic, property, state, structure, item, or result. The
`
`exact allowable degree of deviation from absolute completeness may in some cases
`
`depend on the specific context. However, generally speaking the nearness of completion
`
`will be so as to have the same overall result as if absolute and total completion were
`
`obtained. The use of “substantially” is equally applicable when used in a negative
`
`connotation to refer to the complete or near complete lack of an action, characteristic,
`
`property, state, structure, item, or result. For example, a composition that is
`
`“substantially frcc of ’ particles would either complctcly lack particles, or so ncarly
`
`completely lack particles that the effect would be the same as if it completely lacked
`
`particles. In other words, a composition that is “substantially free of ’ an ingredient or
`
`element may still actually contain such item as long as there is no measurable effect
`
`1O
`
`15
`
`20
`
`25
`
`thereof.
`
`As used hcrcin, a plurality of itcms, structural clcmcnts, compositional clcmcnts,
`
`and/ or materials may be presented in a common list for convenience. However, these
`
`lists should be construed as though each member of the list is individually identified as a
`
`separate and unique member. Thus, no individual member of such list should be
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`construed as a defacto equivalent of any other member of the same list solely based on
`
`their presentation in a common group without indications to the contrary.
`
`Concentrations, amounts, and other numerical data may be expressed or presented
`
`herein in a range format. It is to be understood that such a range format is used merely
`
`for convenience and brevity and thus should be interpreted flexibly to include not only the
`
`numerical values explicitly recited as the limits of the range, but also to include all the
`
`individual numerical values or sub—ranges encompassed within that range as if each
`
`numerical value and sub—range is explicitly recited. As an illustration, a numerical range
`
`of “about 1 wt% to about 5 wt%” should be interpreted to include not only the explicitly
`
`1O
`
`recited values of about 1 wt% to about 5 wt%, but also include individual values and sub-
`
`ranges within the indicated range. Thus, included in this numerical range are individual
`
`values such as 2, 3.5, and 4 and sub—ranges such as from 1-3, from 2-4, and from 3-5, etc.
`
`This same principle applies to ranges reciting only one numerical value. Furthermore,
`
`such an interpretation should apply regardless of the breadth of the range or the
`
`15
`
`characteristics being described.
`
`Methods and systems for ink—jet ink printing on non—porous substrates, such as
`
`Vinyl media, are described herein. In particular the present embodiments utilize an ink—jet
`
`ink comprising polymer particles that are configured to provide a durable print film on a
`
`Vinyl medium, where the particles are also configured to be part of a stable ink—jettable
`
`ink composition.
`
`In an embodiment, the polymer particles can comprise a mixture of
`
`acrylic latex particles and urethane latex particles. The combination of particles can
`
`provide printing with increased durability when compared to inks including only acrylic
`
`latcx.
`
`Also, the mixture of acrylic and urethane polymer particles can be formulated to
`
`fuse upon reaching an appropriate temperature after being printed and thereby create a
`
`film that encapsulates the printed image. The film produced can be durable enough to
`
`protect the printed image from damage due to physical and chemical rubbing. The film
`
`can also providc addcd watcrfastncss to the image. The durability and watcrfastncss
`
`improvements resulting from the present embodiments can include greatly improved
`
`highlighter smearfastness, rub resistance, wet smudge resistance and optical density (after
`
`highlighting smear). Incorporation of such a mixture of latex polymers to the ink—jettable
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`ink dispersions can help to increase the tensile strength of the film formed on a media and
`
`hence the enhanced print durability.
`
`Acrylic latexes are amenable to inclusion in compositions that can be reliably
`
`jetted from ink—jet printing architecture. However acrylic polymers alone can exhibit
`
`poor durability, and particularly poor rubfastness and smearfastness using a dry rub test
`
`and an ammonia cleaning solvent (e. g. WINDEX®) when printed on vinyl media. One
`
`approach to enhancing durability is to increase the amount ofpolymer in the ink. For
`
`example, conventional pigment—based inks often include acrylic polymer particles in
`
`amounts around twice that of the pigment present. However, jettability of an ink
`
`1O
`
`decreases significantly as the amount of solid particulates dispersed therein increases.
`
`This is even more of a concern when attempting to formulate an ink that provides good
`
`color intensity when printed. Such a formulation can call for a pigment content of up to
`
`about 5 wt%. Adding enough acrylic polymer to such an ink so as to confer acceptable
`
`durability can result in an ink having a high enough solid content that jetting performance
`
`15
`
`is impaired.
`
`In inks according to the present embodiments, print durability is enhanced by
`
`including a mixture of acrylic polymer particles and urethane polymer particles. More
`
`particularly, this approach can involve substituting urethane polymer for a portion of the
`
`acrylic polymer one would normally include in a high—durability ink formulation.
`
`Because urethane polymers are generally more durable than acrylic polymers, the same
`
`durability can be obtained from a smaller amount of urethane polymer as compared to
`
`acrylic polymer. One aspect of the present embodiment is that an ink comprising a
`
`mixturc of acrylic and urcthanc can providc bcttcr durability pcr unit of solid content than
`
`inks with only acrylic polymers. In another aspect, an ink comprising an acrylic and
`
`urethane mixture can include a lower particulate content than a given acrylic—based ink,
`
`while exhibiting a similar or greater level of durability than acrylic—based ink.
`
`In a particular embodiment, an ink—jet ink composition can comprise an aqueous
`
`liquid vchiclc, a colorant, and a sct of polymer particlcs including acrylic latcx particles
`
`and urethane particles dispersed within the ink. In one aspect, the acrylic polymer content
`
`of the ink and the urethane polymer content are present in substantially distinct particles.
`
`That is, a portion of the particles dispersed in the ink consist essentially of urethane
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`polymer and these particles are distinct from other particles in the ink that consist
`
`essentially of acrylic polymer. In such an embodiment, the relative content of acrylic and
`
`urethane in the ink is reflected in the relative numbers of each kind of particle present. In
`
`an alternative embodiment, the ink may include acrylic—urethane hybrid polymers, where
`
`the ratio of acrylic to urethane can be configured by selecting the polymer ratios of
`
`individual particles.
`
`The amounts of each polymer included in the ink can be selected to provide a
`
`desired level of durability (rubfastness, waterfastness, and/or smearfastness), while
`
`providing a stable dispersion of solids so that the resulting composition is reliably
`
`jettable. The total amount of the polymer particles in the ink can be in the range of from
`
`about 0.5 wt% to about 40 wt%, or more particularly from about 1 wt% to about 15 wt%,
`
`or still more particularly from about 3 wt% to about 6 wt%. According to one
`
`embodiment, the ink can be a pigment—based ink comprising pigment at from about 1
`
`wt% to about 5 wt%, or from about 2 wt% to about 4 wt%. The acrylic polymer particles
`
`can be present at from about 1 wt% to about 5 wt%, and the urethane polymer particles
`
`can be present at from about 0.3 wt% to about 3 wt%.
`
`In one particular embodiment, the percentage of acrylic polymer replaced with
`
`urethane can be from about 5 wt% to about 50 wt%, and the urethane replacing it can
`
`constitute from about 1% to about 30% of the total resulting polymer mixture. To
`
`illustrate the improvement of using both types of polymer (acrylic and urethane) over
`
`using a larger amount of just acrylic polymer, the durability and jettability of an ink
`
`containing pigment and acrylic polymer at weight percentage ratio of 1 :2 can be exceeded
`
`in an ink containing pi gmcnt, acrylic polymcr, and urcthanc polymcr at a rcspcctivc ratio
`
`of 1 :1:0.5, for example.
`
`In another exemplary embodiment, an ink can feature a pigment
`
`to acrylic to urethane ratio of about 1:1:0.3 with improved results over an ink without
`
`urethane, but with more acrylic polymer.
`
`In still another exemplary embodiment, a
`
`pigment to acrylic to urethane ratio can be about 1 :1 3:03 with improved results. These
`
`cxamplcs arc prcscntcd for illustration, and should not bc construcd as limiting thc
`
`number of ratios possible within the replacement range taught above. Stated more
`
`generally, the inks prepared in accordance with embodiments of the present disclosure
`
`can have a pigment to total polymer ratio of about 1:1 to about 1:2, where the total
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`polymer content has an acrylic to urethane weight ratio of about 120.2 to about 1:1. In
`
`another embodiment, the acrylic polymer particles to urethane polymer particles weight
`
`ratio can be about 1.3:0.3 to about 1:0.5.
`
`As discussed above, increasing polymer content can have the effect of increased
`
`durability but generally at the expense of degraded jettability. In the embodiments of the
`
`present disclosure, both of these properties can be improved by the replacement of some
`
`percentage of the acrylic polymer with a smaller amount of urethane polymer. It should
`
`be noted that the term “replacement” as used in this context does not refer to modifying
`
`an already formulated acrylic—based ink. Rather, it generally refers to a difference in the
`
`way two inks are formulated, where a first ink includes an amount of acrylic but no
`
`urethane, and a second ink includes less acrylic than the first and also includes an amount
`
`ofurethane. In a particular embodiment, the amount of urethane can be less than the
`
`difference in the amount of acrylic present in the inks.
`
`The acrylic polymer particles can be prepared by conventional emulsion
`
`polymerization techniques such as batch, semi—batch, or mini-emulsion processes. In a
`
`particular embodiment, the acrylic particles can comprise a polymerized hydrophobic
`
`monomer or a copolymer with a significant fraction of hydrophobic monomers.
`
`Hydrophobic monomer can be present in amounts of up to about 98%. Hydrophobic
`
`monomers provide durability to the resulting print film and therefore result in the printed
`
`ink having substantial rubfastness and waterfastness. Hydrophobic monomers that are
`
`suitable for use in the core or the shell include but are not limited to methyl acrylate, ethyl
`
`acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, lauryl acrylate, octadecyl acrylate,
`
`mcthyl mcthacrylatc, cthyl mcthacrylatc, propyl mcthacrylatc, butyl mcthacrylatc, hcxyl
`
`methacrylate, lauryl methacrylate, octadecyl methacrylate, 2—ethylhexyl acrylate, 2—
`
`ethylhexyl methacrylate, methylstyrene, vinylbenzyl chloride, acrylonitrile,
`
`methacrylonitrile, and styrene. The monomers used can be selected to provide desired
`
`results in view of printing conditions, the ink—jet system to be used, or the particular
`
`mcdium onto which printing is done.
`
`In a more particular cmbodimcnt, the acrylic
`
`polymer includes at least two of styrene, butyl acrylate, and methacrylonitrile.
`
`A small amount of copolymerized acidic monomer, e. g., from 0.1 wt% to about 30
`
`wt%, can optionally be included with the hydrophobic monomers to facilitate synthesis of
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`10
`
`the polymer. Suitable acidic monomers include acrylic acid, methacrylic acid, itaconic
`
`acid, maleic acid, vinyl benzoic acid, and styrenesulfonates or their derivatives. These
`
`monomers provide surface charge to the particles so as to stabilize them in water. The
`
`imparted charge can be further enhanced by raising the pH of the ink so that the carboxyl
`
`group is converted to the salt form.
`
`In a particular embodiment, the acrylic polymer particles can also include cross—
`
`linking to provide shear strength to the particles before and during jetting. Cross—linking
`
`monomers can be present in the polymer up to about 25 wt%. Suitable cross—linking
`
`monomers include polyfunctional monomers and oligomers that contain an organic
`
`functional group available for cross—linking after polymerization. Cross—linking
`
`monomers that can be used include, without limitation, ethylene glycol dimethacrylate,
`
`diethylene glycol dimethacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate,
`
`1,6—hexanediol diacrylate, tetraethylene glycol diacrylate, tripropylene glycol diacrylate,
`
`ethoxylated bisphenol A diacrylate, pentaerythritol tri— and tetraacrylate, N,N’—
`
`methylenebisacrylamide, divinylbenzene, and combinations thereof, mixtures thereof, and
`
`derivatives thereof.
`
`The urethane particles can comprise any combination of constituent monomers
`
`that can react to form polyurethanes.
`
`In a particular aspect, at least two constituent
`
`monomers are used, the first monomer being a molecule having at least two isocyanate
`
`moieties, such as a diisocyanate. Some examples of diisocyanates that may be used
`
`include isophorone diisocyanate, tolylene—2—4—diisocyanate, hexamethylene diisocyanate,
`
`napthalene diisocyanate, 2,4—toluene diisocyanate, 2,6—toluene diisocyanate, methylene
`
`diphcnyl—4,4'—diisocyanatc, 1,4—tctramcthylcnc diisocyanatc, and biphcnyl diisocyanatc.
`
`In the same aspect, the second monomer may be a polyol, e. g. a diol. Potential
`
`constituent diols include C2-C3 diols as well as polyglycols, including ethylene glycol,
`
`propylene glycol, polyethylene glycols, polypropylene glycols, bisphenol—A,
`
`hydroquinone, and polybutylene glycols. These can be reacted to produce urethane
`
`linkagc groups or polyurcthancs. Commcrcially availablc urcthanc latcx polymers that
`
`are known to be suitable for use in paints, inks, and other colorant compositions can be
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`used in the present embodiments.
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`11
`
`The liquid vehicle can be chosen for suitability with a particular ink—j et printing
`
`system or for use with a particular print medium. As discussed above, the particles
`
`described herein provide a particular benefit for formulating aqueous ink—jet inks that
`
`produce good results on non—porous print media such as vinyl. As such, in a particular
`
`embodiment, the ink—jet ink vehicle is an aqueous vehicle.
`
`The vehicle can consist essentially of water. Alternatively, additional co—solvents
`
`can be included in a vehicle that is predominantly water. More particularly, the vehicle
`
`can include organic co—solvents known in the art to be suited for formulating aqueous ink—
`
`jet inks. Suitable water soluble organic co—solvents, but are not limited to, aliphatic
`
`alcohols, aromatic alcohols, diols, triols, glycol ethers, poly(glycol) ethers, lactams,
`
`formamides, acetamides, long chain alcohols, ethylene glycol, propylene glycol,
`
`diethylene glycols, triethylene glycols, glycerine, dipropylene glycols, glycol butyl ethers,
`
`polyethylene glycols, polypropylene glycols, amides, ethers, carboxylic acids, esters,
`
`organosulfldes, organosulfoxides, sulfones, alcohol derivatives, carbitol, butyl carbitol,
`
`cellosolve, ether derivatives, amino alcohols, and ketones. In particular, the co—solvent
`
`included can have a vapor pressure such that it will evaporate under heating as least as
`
`quickly as the water in the vehicle. In a more particular embodiment, the co—solvent
`
`evaporates more quickly than the water upon application of heat.
`
`The pigments suitable for use in the ink—jet ink are not particularly limited, and
`
`inorganic pigments or organic pigments may be used. Suitable inorganic pigments
`
`include, for example, titanium oxide, cobalt blue (COO-A1203), chrome yellow (PbCrO4),
`
`and iron oxide. Suitable organic pigments include, for example, azo pigments, polycyclic
`
`pigmcnts (c.g., phthalocyaninc pigmcnts, pcrylcnc pigmcnts, pcrynonc pigments,
`
`anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo
`
`pigments, isoindolinone pigments and quinophthalone pigments), dye chelates (e. g., basic
`
`dye type chelates and acidic dye type chelate), nitropigments, nitroso pigments, and the
`
`like.
`
`In conjunction with thcsc or other pigmcnts, non—limiting examples of dispcrsants
`
`that can be used in the formulations of exemplary embodiments of the present disclosure
`
`include Solsperse 32000, Solsperse 39000, Solsperse 5000, Solsperse 22000, Disperbyk
`
`1O
`
`15
`
`20
`
`25
`
`30
`
`

`

`WO 2011/028201
`
`PCT/US2009/055904
`
`12
`
`163, Disperbyk 167, Disperbyk 168, Disperbyk 180, Disperbyk 190, Disperbyk 191, or
`
`the like.
`
`The ink—jet ink compositions can optionally also include wetting agents. Non—
`
`limiting examples of such wetting agents can include siliconepolyether acrylate such as
`
`Tego Rad 2200 N, Tego Rad 2300, and Byk 358N. The inks can also include polyether
`
`modified poly—dimethyl—siloxane wetting agents such as Byk 333, Byk 307, and Silwet L—
`
`7604. If used, wetting agents can be present at from 0.01% to about 10% by weight of
`
`the ink—j et ink composition.
`
`The ink jet ink can further include other additives as needed to provide storage
`
`stability and jettability, including biocides, humectants, buffers, viscosity modifiers,
`
`sequestering agents, and stabilizing agents.
`
`This system and method can provide durable and waterfast printing on media on
`
`which it is typically difficult to achieve such results.
`
`In particular, the system and method
`
`can be used for printing on media that do not absorb liquid inks well. These include non—
`
`porous surfaces such as vinyl. Polymer particles in accordance with the embodiments
`
`described herein, when formulated in an ink—j et ink, have been found to provide
`
`unexpectedly good results on vinyl media. Therefore, in a particular embodiment, the
`
`system and method includes printing on vinyl media with inks formulated for printing on
`
`vinyl media.
`
`By selection of the monomer mixtures in each of the polymers, the polymers can
`
`be constituted so as to have a Tg that facilitates film formation under particular print and
`
`heating conditions. According to a particular embodiment, the Tg of the latex particles
`
`can gcncrally be in the range of from about —40 0C to about 125 0C. More particularly, the
`
`Tg can be from about 0 °C to about 75 OC , or still more particularly from about 15 0C to
`
`1O
`
`15
`
`20
`
`25
`
`about 45 oC.
`
`Print films formed from high Tg polymers can provide enhanced durability to a
`
`printed image encapsulated therewith. Therefore, in another particular embodiment,
`
`polymcrs having a high Tg can be utilized. Generally, a high Tg polymer can be any
`
`polymer having a Tg of at least 45 0C.
`
`In one embodiment, the high Tg polymer can have
`
`30
`
`a T,g from about 45 0C to about 125 0C o