EP0475075A1
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EP
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Ink compositions containing modified pigment particles
Assignee: Xerox Corp
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Filing: 1991-08-06
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Granted: —
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Expires: 2011-08-06
Abstract
Abstract Disclosed is an ink composition comprising an aqueous liquid vehicle and pigment particles having attached to the surfaces thereof a polymerized vinyl aromatic salt. In one embodiment, the polymeric vinyl aromatic salt is chemically grafted to the surfaces of the pigment particles; in another embodiment, the polymeric vinyl aromatic salt is adsorbed onto the surfaces of the pigment particles. Preferably, the modified pigment particles have an average particle diameter of less than about 1 micron. The ink composition is suitable for applications such as ink jet printing processes, particularly thermal ink jet printing processes. Images generated with ink compositions of the present invention are sharp, waterfast, lightfast, and of high optical density, exhibiting no feathering, and can be electrically conductive.
Inventors
- 👤 John W-P Lin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 01:31
CPC Classifications
C; C08; C08F; C08F290/00; C08F290/02; B; B82; B82Y; B82Y30/00; C09; C09B; C09B67/00; C09B67/0001; C09B67/0004; C09B67/0008; C09B67/0013; C09B68/00; C09B68/20; C09B68/26; C09B68/40; C09B68/42; C09B68/425; C09B68/4253; C09B68/46; C09C; C09C1/00; C09C1/44; C09C1/48; C09C1/56; C09C3/00; C09C3/10; C09D; C09D11/00; C09D11/30; C09D11/32; C09D11/322; C01; C01P; C01P2004/00; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/22; C01P2006/60; C01P2006/80
Claims Analysis
Total Claims: 51
Claim 1
Independent Claim
22 words
An ink composition comprising an aqueous liquid vehicle and pigment particles having attached to the surfaces thereof a polymerized vinyl aromatic salt.
Claim 2
Dependent Claim
23 words
An ink composition according to claim 1 wherein the polymerized vinyl aromatic salt is chemically grafted to the surfaces of the pigment particles.
Claim 3
Dependent Claim
22 words
An ink composition according to claim 1 wherein the polymerized vinyl aromatic salt is adsorbed onto the surfaces of the pigment particles.
Claim 4
Dependent Claim
13 words
An ink composition according to claim 1 wherein the pigment is carbon black.
Claim 5
Dependent Claim
30 words
An ink composition according to claim 1 wherein the pigment particles are nonmutagenic nontoxic carbon black particles with a polyaromatic hydrocarbon content of less than about 1 part per million.
Claim 6
Dependent Claim
34 words
An ink composition according to claim 1 wherein the pigment is selected from the group consisting of cyan pigments, magenta pigments, yellow pigments, red pigments, blue pigments, green pigments, orange pigments, and mixtures thereof.
Claim 7
Dependent Claim
59 words
An ink composition according to claim 1 wherein the vinyl aromatic salt is of the formula wherein R is an aromatic moiety, X is an acid salt functional group, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, aromatic groups, substituted aromatic groups, heterocyclic groups, and substituted heterocyclic groups.
Claim 8
Dependent Claim
16 words
An ink composition according to claim 1 wherein the liquid vehicle comprises water and a humectant.
Claim 9
Dependent Claim
53 words
An ink composition according to claim 8 wherein the humectant is selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycols, glycerine, dipropylene glycols, polyethylene glycols, polypropylene glycols, amides, ethers, carboxylic acids, esters, alcohols, organosulfides, organosulfoxides, sulfones, alcohol derivatives, carbitol, butyl carbitol, cellusolve, ether derivatives, amino alcohols, ketones, and mixtures thereof.
Claim 10
Dependent Claim
40 words
An ink composition according to claim 8 wherein the liquid vehicle comprises water in an amount of from about 40 to 100 percent by weight and a humectant in an amount of from 0 to about 60 percent by weight.
Claim 11
Dependent Claim
24 words
An ink composition according to claim 1 wherein the pigment particles have an average particle diameter of from about 0.001 to about 10 microns.
Claim 12
Dependent Claim
22 words
An ink composition according to claim 1 wherein the pigment particles have an average particle diameter of less than about 1 micron.
Claim 13
Dependent Claim
38 words
An ink composition according to claim 1 wherein the pigment particles having the polymerized vinyl aromatic salt attached thereto are present in the ink composition in an amount of from about 0.1 to about 15 percent by weight.
Claim 14
Dependent Claim
81 words
An ink composition according to claim 1 wherein the vinyl aromatic salt is of the formula wherein R is an aromatic moiety with from 6 to about 20 carbon atoms, X is an acid salt functional group consisting of both cation and anion moieties, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups with from 1 to about 20 carbon atoms, aromatic groups with from 6 to about 20 carbon atoms, and heterocyclic groups.
Claim 15
Dependent Claim
29 words
An ink composition according to claim 14 wherein R is selected from the group consisting of phenyl, substituted phenyl, naphthyl, substituted naphthyl, anthracenyl, substituted anthracenyl, and heterocyclic aromatic rings.
Claim 16
Dependent Claim
48 words
An ink composition according to claim 14 wherein X is a salt functional group wherein the cation is selected from the group consisting of Rb⁺, Cs⁺, K⁺, Na⁺, Li⁺, ammonium, and substituted ammonium, and the anion is selected from the group consisting of sulfonate, carboxylate, phosphate, and borate.
Claim 17
Dependent Claim
16 words
An ink composition according to claim 1 wherein the vinyl aromatic salt is of the formula
Claim 18
Dependent Claim
17 words
An ink composition according to claim 1 wherein the vinyl aromatic salt is a styrene sulfonate salt.
Claim 19
Dependent Claim
12 words
An ink composition according to claim 1 which also contains a dye.
Claim 20
Dependent Claim
24 words
An ink composition according to claim 19 wherein the dye is present in an amount of no more than about 15 percent by weight.
Claim 21
Dependent Claim
29 words
An ink composition according to claim 1 which also contains a dispersing agent selected from the group consisting of cationic dispersing agents, anionic dispersing agents, and nonionic dispersing agents.
Claim 22
Dependent Claim
25 words
An ink composition according to claim 21 wherein the dispersing agent is present in an amount of no more than about 40 percent by weight.
Claim 23
Dependent Claim
15 words
An ink composition according to claim 1 which also contains a water soluble polymeric additive.
Claim 24
Dependent Claim
51 words
An ink composition according to claim 23 wherein the polymeric additive is selected from the group consisting of Gum Arabic, polyacrylate salts, polymethacrylate salts, polyvinyl alcohols, polyethylene oxides, poyethylene glycols, polypropylene glycols, hydroxy propylcellulose, hydroxyethylcellulose, polyvinylpyrrolidinone, polyvinylether, starch, polyacrylamide, lignin sulfonate salts, copolymers of naphthalene sulfonate salts and formaldehyde, and polysaccharides.
Claim 25
Dependent Claim
26 words
An ink composition according to claim 23 wherein the polymeric additive is present in an amount of from about 0.01 to about 5 percent by weight.
Claim 26
Dependent Claim
89 words
A process for preparing an ink composition which comprises mixing in water a pigment and a vinyl aromatic salt, attriting the mixture until the pigment particles have an average particle diameter of from about 0.001 to about 20 microns, adding to the mixture a water soluble free radical polymerization initiator and heating the mixture under vacuum or inert atmosphere, thereby polymerizing the vinyl aromatic salt and attaching it to the pigment particle surfaces, separating the pigment particles from the mixture, and admixing the pigment particles with a liquid vehicle.
Claim 27
Dependent Claim
41 words
A process according to claim 26 wherein subsequent to admixing the pigment particles with the liquid vehicle, the ink composition is subjected to centrifugation and filtration to remove pigment particles with an average particle diameter of greater than about 1 micron.
Claim 28
Dependent Claim
27 words
A process according to claim 26 wherein polymerization of the monomeric vinyl aromatic salt is carried out at a temperature of from about 20 to about 120°C.
Claim 29
Dependent Claim
30 words
A process according to claim 26 wherein the mixture of water, pigment, and monomeric vinyl aromatic salt is attrited for a period of from about 0.25 to about 48 hours.
Claim 30
Dependent Claim
92 words
A process according to claim 26 wherein prior to polymerization the mixture comprises water in an amount of from about 35 to about 98 percent by weight, pigment particles in an amount of from about 2 to about 65 percent by weight, monomeric vinyl aromatic salt in an amount of from about 0.02 to about 50 percent by weight, free radical polymerization initiator in an amount of from about 0.01 to about 15 percent by weight, and a wetting agent in an amount of from 0 to about 50 percent by weight.
Claim 31
Dependent Claim
58 words
A process according to claim 26 wherein the vinyl aromatic salt is of the formula wherein R is an aromatic moiety, X is an acid salt functional group, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, aromatic groups, substituted aromatic groups, heterocyclic groups, and substituted heterocyclic groups.
Claim 32
Dependent Claim
28 words
A process according to claim 31 wherein R is selected from the group consisting of phenyl, substituted phenyl, naphthyl, substituted naphthyl, anthracenyl, substituted anthracenyl, and heterocyclic aromatic rings.
Claim 33
Dependent Claim
34 words
A process according to claim 26 wherein the pigment particles having attached to the surfaces thereof the polymerized vinyl aromatic salts have an average particle diameter of from about 0.001 to about 10 microns.
Claim 34
Dependent Claim
32 words
A process according to claim 26 wherein the pigment particles having attached to the surfaces thereof the polymerized vinyl aromatic salts have an average particle diameter of less than about 1 micron.
Claim 35
Dependent Claim
37 words
A process according to claim 26 wherein the pigment particles having the polymerized vinyl aromatic salt attached thereto are present in the ink composition in an amount of from about 0.1 to about 15 percent by weight.
Claim 36
Dependent Claim
80 words
A process according to claim 26 wherein the vinyl aromatic salt is of the formula wherein R is an aromatic moiety with from 6 to about 20 carbon atoms, X is an acid salt functional group consisting of both cation and anion moieties, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups with from 1 to about 20 carbon atoms, aromatic groups with from 6 to about 20 carbon atoms, and heterocyclic groups.
Claim 37
Dependent Claim
15 words
A process according to claim 26 wherein the vinyl aromatic salt is of the formula
Claim 38
Dependent Claim
16 words
A process according to claim 26 wherein the vinyl aromatic salt is a styrene sulfonate salt.
Claim 39
Dependent Claim
121 words
A process for preparing an ink composition which comprises: a. preparing modified pigment particles by: i. first mixing together in water a free radical polymerization initiator and a monomeric vinyl aromatic salt and heating the mixture under vacuum or inert atmosphere, thereby polymerizing the vinyl aromatic salt; and ii. subsequently adding to the polymerized vinyl aromatic salt pigment particles with an average particle diameter of from about 0.001 to about 10 microns, additional vinyl aromatic salt monomers, and, optionally, additional free radical polymerization initiator, thereby further polymerizing the vinyl aromatic salt and resulting in attachment of the polymerized vinyl aromatic salt to the surfaces of the pigment particles; and b. admixing the modified pigment particles thus prepared with a liquid vehicle.
Claim 40
Dependent Claim
116 words
A process for preparing an ink composition which comprises: a. preparing modified pigment particles by: i. first mixing together in water pigment particles with an average particle diameter of from about 0.001 to about 10 microns, a monomeric vinyl aromatic salt, and a free radical polymerization initiator and heating the mixture under vacuum or inert atmosphere, thereby polymerizing the vinyl aromatic salt; and ii. subsequently adding to the mixture additional vinyl aromatic salt monomers and, optionally, additional free radical polymerization initiator, thereby further polymerizing the vinyl aromatic salt, wherein the polymerized vinyl aromatic salt is attached to the surfaces of the pigment particles; and b. admixing the modified pigment particles thus prepared with a liquid vehicle.
Claim 41
Dependent Claim
56 words
A process for generating images onto a substrate which comprises incorporating into an ink jet printing apparatus an ink composition comprising an aqueous liquid vehicle and pigment particles having attached to the surfaces thereof a polymerized vinyl aromatic salt and causing droplets of the ink composition to be ejected in an imagewise pattern onto the substrate.
Claim 42
Dependent Claim
26 words
A process according to claim 41 wherein the substrate is selected from the group consisting of plain paper, silica coated paper, transparency material, fabric, and plastic.
Claim 43
Dependent Claim
18 words
A process according to claim 41 wherein the ink jet printing apparatus is a thermal ink jet printer.
Claim 44
Dependent Claim
59 words
A process according to claim 41 wherein the vinyl aromatic salt has monomers of the formula wherein R is an aromatic moiety, X is an acid salt functional group, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups, substituted alkyl groups, aromatic groups, substituted aromatic groups, heterocyclic groups, and substituted heterocyclic groups.
Claim 45
Dependent Claim
80 words
A process according to claim 41 wherein the vinyl aromatic salt is of the formula wherein R is an aromatic moiety with from 6 to about 20 carbon atoms, X is an acid salt functional group consisting of both cation and anion moieties, and R₁, R₂, and R₃ are independently selected from the group consisting of hydrogen, alkyl groups with from 1 to about 20 carbon atoms, aromatic groups with from 6 to about 20 carbon atoms, and heterocyclic groups.
Claim 46
Dependent Claim
15 words
A process according to claim 41 wherein the vinyl aromatic salt is of the formula
Claim 47
Dependent Claim
16 words
A process according to claim 41 wherein the vinyl aromatic salt is a styrene sulfonate salt.
Claim 48
Dependent Claim
15 words
A process according to claim 41 wherein the image on the substrate is electrically conductive.
Claim 49
Dependent Claim
32 words
A process according to claim 41 wherein the substrate is plain paper and the image on the substrate has an optical density of from about 1.0 to about 1.45 optical density units.
Claim 50
Dependent Claim
33 words
A process according to claim 41 wherein the substrate is silica coated paper and the image on the substrate has an optical density of from about 1.2 to about 1.78 optical density units.
Claim 51
Dependent Claim
38 words
A process according to claim 41 wherein the image on the substrate exhibits waterfastness of greater than about 95 percent, lightfastness of greater than about 95 percent, and a resolution of at least about 288 spots per inch.
References Cited (Backward Citations)
DE2559375A1
Cited
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