Image formation method

Abstract

To provide an image formation method with which it is possible to form an image having high durability without causing texture deterioration.SOLUTION: An image formation method includes: applying a processing liquid onto a fabric including a fiber having a hydroxy group; and applying ink onto the fabric including the fiber having the hydroxy group by inkjet system. The ink includes a pigment, a pigment dispersant that adsorbs to the pigment and includes a carboxylic acid group, and an aqueous solvent. The processing liquid includes salt of phosphorus-containing acid, and an aqueous solvent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an image forming method. [Background technology]

[0002] In recent years, ink-jet printing, in which an image is formed on a fabric by an ink-jet method, has become widely used as a textile printing method because it allows dyeing in a short time and has high production efficiency.

[0003] Dye inks have been the mainstream inks used in inkjet textile printing, but in recent years, the use of pigment inks has been considered, which allows for the elimination of post-treatments such as a washing step to wash away dye that has not dissolved or reacted.

[0004] Pigment inks exhibit high color development by retaining pigment particles on the surface of fabrics, but tend to have poorer pigment particle fixation and poorer fastness than dye inks. Therefore, in printing using aqueous inkjet inks, it has been proposed to use a crosslinking agent in the pretreatment liquid, image-forming ink, and post-treatment ink set to improve fastness.

[0005] For example, Patent Document 1 discloses an inkjet printing ink containing (A) a pigment dispersion, (B) a water-soluble fixing agent, and (C) a crosslinking agent. It is disclosed that the water-soluble pigment dispersant contained in (A) the pigment dispersion is a neutralized product of a copolymer of a (meth)acrylic acid ester monomer, an aliphatic vinyl monomer having a carboxy group, and an aliphatic vinyl monomer having a crosslinkable functional group, and that (B) the water-soluble fixing agent is a water-soluble epoxy resin. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-251062 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as shown in Patent Document 1, when a crosslinkable resin is contained in an ink or a treatment liquid, the resin in the ink applied to the fabric tends to harden due to the crosslinkable resin. This causes a problem of loss of texture. Therefore, it is desirable to improve fastness without causing a loss of texture.

[0008] The present invention has been made in view of the above circumstances, and has as its object to provide an image forming method capable of forming an image having high fastness without causing deterioration in texture. [Means for solving the problem]

[0009] The above problem can be solved by the following configuration.

[0010] [1] An image forming method comprising the steps of: applying a treatment liquid onto a fabric containing fibers having hydroxyl groups; and applying an ink onto the fabric containing fibers having hydroxyl groups by an inkjet method, wherein the ink comprises a pigment, a pigment dispersant containing a carboxyl group adsorbed on the surface of the pigment, and an aqueous solvent; and the treatment liquid comprises a salt of a phosphorus-containing acid and an aqueous solvent. [2] The image forming method according to [1], wherein the salt of the phosphorus-containing acid includes an alkali metal salt of the phosphorus-containing acid. [3] The image forming method according to [1] or [2], wherein the content of the salt of a phosphorus-containing acid in the treatment liquid is 0.1 to 5.0% by mass relative to the treatment liquid. [4] The image forming method according to any one of [1] to [3], wherein the treatment liquid further contains a polycarboxylic acid. [5] The image forming method according to [4], wherein the polycarboxylic acid is selected from the group consisting of citric acid, tartaric acid, and malic acid. [6] The image forming method according to [4] or [5], wherein the content of the polycarboxylic acid in the treatment liquid is 0.1 to 5.0% by mass with respect to the treatment liquid. [7] The image forming method according to any one of [1] to [6], wherein the mass ratio X / Y of the adhesion amount X of the salt of a phosphorus-containing acid to the adhesion amount Y of the pigment dispersant on the fabric is 1 to 50. [8] The image forming method according to any one of [1] to [7], wherein the pigment dispersant contains a polymer containing a structural unit derived from a carboxy group-containing monomer. [9] The image forming method according to any one of [1] to [8], wherein in the step of applying the ink, the ink is applied wet-on-wet onto the fabric to which the treatment liquid has been applied.

[10] The image forming method according to any one of [1] to [9], wherein the fabric contains cotton. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an image forming method capable of forming an image having high fastness without causing deterioration in texture or image quality. DETAILED DESCRIPTION OF THE INVENTION

[0012] As a result of extensive research, the present inventors have found that by using a treatment liquid containing a salt of a phosphorus-containing acid in combination with an ink containing a pigment dispersion having a carboxyl group on a fabric containing fibers having a hydroxyl group, it is possible to form an image with good fastness and image quality while maintaining a good texture.

[0013] The mechanism behind this is not clear, but is speculated to be as follows. First, the treatment liquid and ink are applied to a fabric, which is then dried. During this process, a crosslinking esterification reaction occurs between the hydroxyl groups of the fabric fibers and the carboxyl groups of the pigment dispersant in the ink, causing the pigment dispersion in the ink to adhere to the fabric. When the treatment liquid contains a salt of a phosphorus-containing acid, the salt of the phosphorus-containing acid specifically functions as a crosslinking catalyst for the esterification reaction, thereby accelerating the reaction and allowing the pigment dispersion in the ink to be well fixed to the fabric, thereby improving fastness.

[0014] The treatment liquid preferably further contains a polycarboxylic acid. The polycarboxylic acid has a carboxy group, which allows it to have good affinity with a pigment dispersant having a carboxy group. Therefore, the hydroxyl groups of the fabric not only react directly with the carboxy group of the pigment dispersant, but also react with the carboxy group of the polycarboxylic acid, thereby indirectly interacting with the pigment dispersant via the polycarboxylic acid. This is thought to further facilitate direct or indirect fixation of the fabric and the pigment dispersion in the ink. Furthermore, the carboxy groups of the polycarboxylic acid and the carboxy groups of the pigment dispersant are thought to form a high-order network structure on the fabric, as they bond with the hydroxyl groups of the fabric, respectively. These factors further improve fixability and fastness.

[0015] An image forming method according to an embodiment of the present invention will be described below.

[0016] 1. Image forming method An image forming method according to one embodiment of the present invention includes the steps of: 1) applying a treatment liquid onto a fabric containing fibers having hydroxyl groups; and 2) applying an ink onto the fabric containing fibers having hydroxyl groups by an inkjet method.

[0017] The order of performing step 1) and step 2) is not particularly limited. For example, step 2) may be performed after step 1), step 1) may be performed after step 2), or step 1) and step 2) may be performed simultaneously. In this embodiment, an example will be described in which step 1) is performed before step 2).

[0018] Step 1) The treatment liquid is applied onto a fabric containing fibers having hydroxyl groups.

[0019] Examples of fibers having hydroxyl groups include cotton and other cellulose fibers. Among these, cotton is preferred. The fabric may be any form of woven fabric, nonwoven fabric, knitted fabric, or the like, made from these fibers. The fabric may also be a blended woven fabric or blended nonwoven fabric made from two or more types of fibers.

[0020] The treatment liquid contains a salt of a phosphorus-containing acid and an aqueous solvent, and will be described in detail later.

[0021] The method for applying the treatment liquid is not particularly limited and may be, for example, a pad method, a coating method, a spray method, an inkjet method, etc. Among these, the spray method or the inkjet method is preferred, and the inkjet method is more preferred, from the viewpoint of enabling faster image formation by simultaneously carrying out steps 1) and 2).

[0022] The amount of treatment liquid applied is not particularly limited and can be adjusted depending on the type of fabric and the amount of ink applied. For example, the treatment liquid is applied so that the mass ratio (X / Y) of the amount of phosphorus-containing acid salt attached to the fabric, X, to the amount of pigment dispersant attached, Y, is preferably 1 to 50, more preferably 1 to 30. This can further promote cross-linking esterification while maintaining the texture of the fabric, thereby further improving fastness.

[0023] Specifically, the amount of the treatment liquid to be applied is not particularly limited, but is, for example, 5 g / m 2 More than 30g / m 2 The following (including solvents) can be used: This can further promote cross-linking esterification while maintaining the texture of the fabric, thereby further improving fastness.

[0024] After the treatment liquid applied to the fabric is dried, step 2) described below may be carried out, or step 2) described below may be carried out before the treatment liquid is completely dried (so-called wet-on-wet). Of these, wet-on-wet is preferred from the viewpoint of facilitating contact between the salt of the phosphorus-containing acid in the treatment liquid and the pigment dispersant in the ink and further promoting the crosslinking esterification reaction.

[0025] Step 2) Next, ink is applied by an inkjet system onto the fabric to which the treatment liquid has been applied.

[0026] The ink contains a pigment, a pigment dispersant, and an aqueous solvent. The pigment dispersant is a polymer dispersant having a carboxy group. The ink will be described in detail later. The amount of ink applied is not particularly limited, but is, for example, 5 g / m 2 More than 30g / m 2 The following (including solvents) can be used:

[0027] The fabric to which the treatment liquid and ink have been applied is then dried.

[0028] The drying method is not particularly limited, and may be performed at room temperature or with heating. The heating method may be a method using a heater, a hot air dryer, a heated roller, or the like, and is preferably a method of heating from both sides of the fabric using a hot air dryer and a heater. The drying temperature is not particularly limited as long as it can remove the aqueous solvent in the treatment liquid or ink and promote the above-mentioned crosslinking esterification reaction, and can be, for example, 80°C or higher and 180°C or lower.

[0029] In this embodiment, the treatment liquid and ink are applied to the fabric, and as described above, the hydroxyl groups of the fabric fibers and the carboxyl groups of the pigment dispersant in the ink undergo a cross-linking esterification reaction, causing the pigment dispersion in the ink to be fixed to the fabric. The phosphorus-containing acid salt contained in the treatment liquid can function as a crosslinking catalyst that promotes a crosslinking esterification reaction between the hydroxyl groups of the fibers contained in the fabric and the carboxyl groups of the pigment dispersant in the ink, thereby improving the fixability and fastness of the resulting image-formed product without impairing the texture of the fabric.

[0030] Furthermore, if the treatment liquid further contains a polycarboxylic acid, the cross-linking esterification reaction can be further promoted, thereby further improving the fixability and fastness of the image-formed product. Furthermore, if the pigment dispersant in the ink is a block copolymer, the texture can be maintained more favorably.

[0031] Other processes The image forming method may further include other steps as necessary. For example, a step of applying a post-treatment liquid (also called an overcoat liquid) onto the ink applied to the fabric may be further carried out.

[0032] Next, the ink set used in the above-described image forming method will be described.

[0033] 2. Ink set The ink set is used for forming an image on a fabric containing fibers having hydroxyl groups, and includes ink and a treatment liquid.

[0034] 2-1.Ink The ink according to this embodiment contains a pigment, a pigment dispersant, and an aqueous solvent.

[0035] 2-1-1. Pigments The pigment contained in the ink is not particularly limited, but is preferably an organic pigment or an inorganic pigment having the following numbers as listed in the Color Index.

[0036] Examples of orange pigments include Pigment Orange 31 and 43.

[0037] Examples of red or magenta pigments include Pigment Red 3, 5, 19, 22, 31, 38, 43, 48:1, 48:2, 48:3, 48:4, 48:5, 49:1, 53:1, 57:1, 57:2, 58:4, 63:1, 81, 81:1, 81:2, 81:3, 81:4, 88, 104, 108, 112, 122, 123, 144, 146, 149, 166, 168, 169, 170, 177, 178, 179, 184, 185, 208, 216, 226, 257, Pigment Violet 3, 19, 23, 29, 30, 37, 50, 88, and Pigment Orange 13, 16, 20, and 36.

[0038] Examples of blue or cyan pigments include Pigment Blue 1, 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17-1, 22, 27, 28, 29, 36, 60.

[0039] Examples of green or yellow pigments include Pigment Green 7, 26, 36, and 50. Examples of yellow pigments include Pigment Yellow 1, 3, 12, 13, 14, 15, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 128, 137, 138, 139, 151, 153, 154, 155, 157, 166, 167, 168, 180, 185, 193, and 213.

[0040] Examples of black pigments include Pigment Black 7, 28, and 26.

[0041] Commercially available examples of pigments include Cromofine Yellow 2080, 5900, 5930, AF-1300, 2700L, Cromofine Orange 3700L, 6730, Cromofine Scarlet 6750, Cromofine Magenta 6880, 6886, 6891N, 6790, 6887, Cromofine Violet RE, Cromofine Red 6820, 6830, Cromofine Blue HS-3, 5187, 5108, 5197, 5085N, SR-5020, 5026, 5050, 4920, 4927, 4937, 4824, 4933GN-EP, 4940, 4973, 5205, 5208, 5214, 5221, and 5000P. , Cromofine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Cromofine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400(B), 2500, 2600, ZAY-260, 2700(B), 2770 Seika Fast Red 8040, C405(F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seika Fast Carmine 6B1476T-7, 1483LT, 3840, 3870, Seika Fast Bordeaux 10B-430, Seika Light Rose R40, Seika Light Violet B800, 7805, Seika Fast Maroon 460N, Seika Fast Orange 900, 2900, Seika Light Blue C718, A612, Cyanine Blue 4933M, 4933GN-EP, 4940, 4973 (manufactured by Dainichi Seika Color & Chemicals); KET Yellow 401, 402, 403, 404, 405, 406, 416, 424, KET Orange 501, KET Red 301, 302, 303, 304, 305, 306, 307, 308, 309, 310, 336, 337, 338, 346, KET Blue 101, 102, 103, 104, 105, 106, 111, 118, 124, KET Green 201 (manufactured by Dainippon Ink & Chemicals);Colortex Yellow 301, 314, 315, 316, P-624, 314, U10GN, U3GN, UNN, UA-414, U263, Finecol Yellow T-13, T-05, Pigment Yellow1705, Colortex Orange 202, Colortex Red101, 103, 115, 116, D3B, P-625, 102, H-1024, 105C, UFN, UCN, UBN, U3BN, URN, UGN, UG276, U456, U457, 105C, USN, Colortex Maroon601, Colortex BrownB610N, Colortex Violet600, Pigment Red 122, Colortex Blue516, 517, 518, 519, A818, P-908, 510, Colortex Green 402, 403, Colortex Black 702, U905 (manufactured by Sanyo Pigment); Lionol Yellow 1405G, Lionol Blue FG7330, FG7350, FG7400G, FG7405G, ES, ESP-S (manufactured by Toyo Ink Co., Ltd.); Toner Magenta E02, Permanent Rubin F6B, Toner Yellow HG, Permanent Yellow GG-02, Hostapearm Blue B2G (manufactured by Hoechst Industrie); Novoperm P-HG, Hostaperm Pink E, Hostaperm Blue B2G (manufactured by Clariant); carbon black #2600, #2400, #2350, #2200, #1000, #990, #980, #970, #960, #950, #850, MCF88, #750, #650, MA600, MA7, MA8, MA11, MA100, MA100R, MA77, #52, #50, #47, #45, #45L, #40, #33, #32, #30, #25, #20, #10, #5, #44, and CF9 (manufactured by Mitsubishi Chemical);

[0042] From the viewpoint of improving dispersibility in the ink, the pigment is preferably further dispersed with a pigment dispersant, which will be described later.

[0043] The pigment may also be a self-dispersing pigment. A self-dispersing pigment is a pigment particle whose surface is modified with a group having a hydrophilic group, and has pigment particles and hydrophilic groups bonded to the surface. Examples of the hydrophilic group include a carboxy group, a sulfonic acid group, and a phosphorus-containing group. Examples of the phosphorus-containing group include a phosphate group, a phosphonic acid group, a phosphinic acid group, a phosphite group, and a phosphate group.

[0044] Examples of commercially available self-dispersing pigments include Cabot Corporation's Cab-0-Jet (registered trademark) 200K, 250C, 260M, and 270V (sulfonic acid group-containing self-dispersing pigments), Cab-0-Jet (registered trademark) 300K (carboxylic acid group-containing self-dispersing pigments), and Cab-0-Jet (registered trademark) 400K, 450C, 465M, 470V, and 480V (phosphate group-containing self-dispersing pigments).

[0045] The pigment content is not particularly limited, but is preferably 0.3 to 12% by mass of the ink, from the viewpoint of easily adjusting the ink viscosity to the range described below and forming a higher-density image. If the pigment content is 0.3% by mass or more, the color of the resulting image tends to be vivid, and if it is 5% by mass or less, the ink viscosity does not become too high, so ejection stability is less likely to be impaired. From the same viewpoint, the pigment content is more preferably 0.5 to 8% by mass of the ink.

[0046] 2-1-2. Pigment dispersants The pigment dispersant adsorbs to the surface of pigment particles, facilitating dispersion of the pigment in an aqueous medium. The pigment dispersant is a pigment dispersant containing a carboxy group, and specifically, contains a polymer containing a structural unit derived from a carboxy group-containing monomer (hereinafter also referred to as a "polymer having a carboxy group"). The polymer is a polymer containing a structural unit derived from a hydrophilic monomer and a structural unit derived from a hydrophobic monomer, and it is preferable that the hydrophilic monomer contains a carboxy group-containing monomer.

[0047] Examples of the carboxy group-containing monomer include unsaturated carboxylic acids such as (meth)acrylic acid, crotonic acid, maleic acid, and itaconic acid; vinyl monomers obtained by reacting hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate with acid anhydrides such as maleic anhydride, succinic anhydride, and phthalic anhydride; and vinylbenzoic acid. Among these, (meth)acrylic acid is preferred. The hydrophilic monomer may further include a monomer containing a hydrophilic functional group other than a carboxy group (for example, a hydroxyl group, an amino group, a ketone group, or a sulfonic acid group). Examples of such a monomer include a monomer containing an acid anhydride group such as maleic anhydride; a monomer containing a sulfonic acid group such as styrenesulfonic acid or 4-(methacryloyloxy)butylsulfonic acid; and an ethylene oxide-modified (meth)acrylic acid ester monomer such as an ethylene oxide-modified (meth)acrylic acid alkyl ester.

[0048] The hydrophobic monomer may be a vinyl monomer containing an aromatic ring group or an alicyclic hydrocarbon group.

[0049] Examples of vinyl monomers containing an aromatic ring group include (meth)acrylates having an aromatic ring group, such as benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate; and aromatic vinyl monomers, such as styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, and 1-vinylnaphthalene, among which vinyl monomers having an aromatic ring group with 6 to 15 carbon atoms are preferred.

[0050] Examples of vinyl-based monomers having an alicyclic alkyl group include (meth)acrylates having an alicyclic alkyl group such as cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, bornyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate, and vinyl-based monomers having an alicyclic alkyl group having 6 to 15 carbon atoms are preferred.

[0051] Of these, the hydrophobic monomer preferably includes a vinyl monomer having an aromatic ring group with 6 to 15 carbon atoms, such as benzyl (meth)acrylate.

[0052] The polymer having a carboxy group may further contain structural units derived from other monomers than those mentioned above. Examples of the other monomers include alkyl (meth)acrylates such as methyl (meth)acrylate and tert-butyl (meth)acrylate.

[0053] The polymer having a carboxy group may be a random copolymer containing structural units derived from a hydrophilic monomer and structural units derived from a hydrophobic monomer arranged randomly, or may be a block copolymer containing a hydrophilic block and a hydrophobic block. Among these, from the viewpoints of improving adsorption to the pigment and making the cross-linking esterification reaction more likely to occur, a block copolymer is preferred.

[0054] In block copolymers, the hydrophilic and hydrophobic regions are clearly separated, which allows the hydrophobic blocks, which are the hydrophobic regions, to have a higher adsorption to pigment particles than random copolymers. In addition, the action of the carboxyl groups in the hydrophilic blocks is stronger, which makes it easier for crosslinking esterification reactions to occur with the hydroxyl groups of the fabric.

[0055] The "hydrophilic block A" is a block that enhances the affinity with the aqueous solvent contained in the ink and contains a site (carboxy group) that interacts or reacts with the hydroxyl group of the fabric, and refers to the block that has the highest affinity with water among the blocks that make up the copolymer. The number of hydrophilic blocks is 1 to 2, and preferably 2.

[0056] The hydrophilic block A contains structural units derived from hydrophilic monomers. The content of the structural units derived from hydrophilic monomers in the hydrophilic block A is higher than that in the hydrophobic block B. Specifically, the content of the structural units derived from hydrophilic monomers in the hydrophilic block A is preferably 10% by mass or more relative to the hydrophilic block A. When the content of the hydrophilic monomers in the hydrophilic block A is 10% by mass or more, dispersibility in aqueous solvents is likely to be further improved. From the same viewpoint, the content is more preferably 15% by mass or more and 80% by mass or less.

[0057] The hydrophilic block A may further contain a structural unit derived from a monomer other than the hydrophilic monomer. Examples of the other monomer include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate and tert-butyl (meth)acrylate; and the above-mentioned hydrophobic monomers.

[0058] The "hydrophobic block B" is a portion that adsorbs to the pigment, and is the block that has the lowest affinity for the aqueous solvent contained in the ink among the blocks that make up the copolymer. The number of hydrophobic blocks B is not particularly limited, but is preferably one.

[0059] The content of structural units derived from hydrophilic monomers in the hydrophobic block B is lower than the content of structural units derived from hydrophilic monomers in the hydrophilic block A. For example, when a block copolymer includes two hydrophilic blocks A and one hydrophilic block B, the content of structural units derived from hydrophilic monomers in the hydrophobic block B is lower than that in either of the two hydrophilic blocks A. Specifically, the content of structural units derived from hydrophilic monomers in the hydrophobic block B is less than 10% by mass, and preferably 5% by mass or less, relative to the hydrophobic block B.

[0060] The content of the structural units derived from hydrophobic monomers in the hydrophobic block B is preferably 10% by mass or more relative to the hydrophobic block B. When the content is 10% by mass or more, the adsorption to the pigment is likely to be further improved. From the same viewpoint, the content is more preferably 15% by mass or more and 100% by mass or less.

[0061] The hydrophobic block B may further contain a structural unit derived from a monomer other than the hydrophobic monomer. Examples of the other monomer include the above-mentioned (meth)acrylic acid alkyl ester and the above-mentioned hydrophilic monomer.

[0062] Among block copolymers, ABA block copolymers, which have two hydrophilic blocks A and one hydrophobic block B disposed between them, are more preferable than AB block copolymers, which have one hydrophilic block A and one hydrophobic block B. ABA block copolymers contain more carboxyl group-containing moieties (hydrophilic blocks) than AB block copolymers. Therefore, they have more bonding points available for bonding to fabrics, making them more likely to bond strongly to fabrics. This facilitates improved adhesion to fabrics and enhanced washfastness and abrasion resistance. Furthermore, because the copolymer can bond intermittently to fabrics at multiple bonding points, the fabric is less likely to become stiff than if it were continuously bonded at a single bonding point. Therefore, the texture can be better maintained.

[0063] The content of the hydrophobic block B in the ABA block copolymer is preferably 10% by mass or more and 80% by mass or less, and more preferably 20% by mass or more and 80% by mass or less, based on the total mass of the block copolymer. When the content is 10% by mass or more, the content of the hydrophobic block B is high, which makes it easier to improve the adsorption to pigments, and when the content is 80% by mass or less, the content of the hydrophilic block A is high, which makes it easier to improve the affinity to aqueous solvents.

[0064] When the block copolymer contains multiple hydrophilic blocks A, the types and composition ratios of monomers in the multiple blocks A may be the same or different from one another. In particular, it is preferable that the two hydrophilic blocks A have the same monomer composition.

[0065] The weight-average molecular weight of the polymer having a carboxy group is preferably 7,000 or more and 21,000 or less, and more preferably 10,000 or more and 20,000 or less. The larger the weight-average molecular weight, the easier it is to increase the dispersibility of the pigment in an aqueous solvent, and the smaller the weight-average molecular weight, the easier it is to suppress crosslinking and aggregation between pigment dispersions. The weight-average molecular weight of the polymer can be measured by the same method as described above.

[0066] The acid value of the carboxyl group-containing polymer is preferably 40 mgKOH / g or more and 300 mgKOH / g or less, and more preferably 40 mgKOH / g or more and 190 mgKOH / g or less. An acid value of 40 mgKOH / g or more can enhance the hydrophilicity of the pigment dispersant, thereby further improving the dispersibility of the pigment. Furthermore, an acid value of 300 mgKOH / g or less can further prevent the hydrophilicity of the pigment dispersant from becoming excessively high, thereby further improving the water resistance of the resulting image-formed product. The acid value can be measured in accordance with the measurement method of JIS K0070:1992.

[0067] The content of the carboxyl group-containing polymer is preferably 5% by mass or more and 90% by mass or less, and more preferably 15% by mass or more and 80% by mass or less, relative to the pigment. A content of 5% by mass or more can further enhance the dispersibility of the pigment in an aqueous solvent. A content of 90% by mass or less can further suppress an excessive increase in the viscosity of the aqueous ink due to an excessive content of the polymer.

[0068] 2-1-3. Water-based solvents The aqueous solvent preferably contains water and further contains a water-soluble organic solvent.

[0069] The content of water is, for example, 20 to 70% by mass, and preferably 30 to 60% by mass, based on the ink.

[0070] The water-soluble organic solvent is not particularly limited as long as it is compatible with water, but from the viewpoint of facilitating penetration of the ink into the interior of the fabric and preventing loss of ejection stability in the inkjet method, it is preferable that the ink does not easily thicken upon drying. Therefore, it is preferable that the ink contains a high-boiling-point solvent with a boiling point of 200°C or higher.

[0071] The high boiling point solvent having a boiling point of 200° C. or higher may be any water-soluble organic solvent having a boiling point of 200° C. or higher, and is preferably a polyol or a polyalkylene oxide.

[0072] Examples of polyols with a boiling point of 200°C or higher include dihydric alcohols such as 1,3-butanediol (boiling point 208°C), 1,6-hexanediol (boiling point 223°C), and polypropylene glycol; and trihydric or higher alcohols such as glycerin (boiling point 290°C) and trimethylolpropane (boiling point 295°C).

[0073] Examples of polyalkylene oxides having a boiling point of 200°C or higher include ethers of dihydric alcohols such as diethylene glycol monoethyl ether (boiling point 202°C), triethylene glycol monomethyl ether (boiling point 245°C), tetraethylene glycol monomethyl ether (boiling point 305°C), tripropylene glycol monoethyl ether (boiling point 256°C), and polypropylene glycol, as well as ethers of trihydric or higher alcohols such as glycerin (boiling point 290°C) and hexanetriol.

[0074] The solvent may further contain other solvents in addition to the high-boiling point solvent. Examples of the other solvents include polyhydric alcohols having a boiling point of less than 200°C (e.g., ethylene glycol, propylene glycol, hexanetriol, etc.); polyhydric alcohol ethers having a boiling point of less than 200°C (e.g., ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether); monohydric alcohols (e.g., methanol, ethanol, propanol, pentanol, hexanol, cyclohexanol, butyl ether ... benzyl alcohol); amines (e.g., ethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine); amides (e.g., formamide, N,N-dimethylformamide, N,N-dimethylacetamide); heterocycles (e.g., 2-pyrrolidone, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidine), sulfoxides (e.g., dimethyl sulfoxide); and sulfones (e.g., sulfolane).

[0075] The content of the water-soluble organic solvent is, for example, 20 to 70% by mass, and preferably 30 to 60% by mass, relative to the ink.

[0076] 2-1-4. Other ingredients The ink may further contain other components in addition to those described above, as necessary. Examples of the other components include a water-dispersible resin and various additives.

[0077] (Water dispersible resin) The water-dispersible resin can have the function of fixing pigments and the like to fabrics. The water-dispersible resin can be contained in the ink as resin particles.

[0078] Examples of water-dispersible resins include urethane resins, butadiene resins, (meth)acrylic resins, and polystyrene. Examples of butadiene resins include styrene-butadiene copolymers and acrylonitrile-butadiene copolymers. Examples of (meth)acrylic resins include (meth)acrylic acid ester copolymers, styrene-(meth)acrylic copolymers, silicone-(meth)acrylic copolymers, and acrylic-modified fluororesins. Among these, urethane resins and (meth)acrylic acid ester copolymers and styrene-(meth)acrylic copolymers are preferred. These are presumed to bond with the block copolymer through intermolecular hydrogen bonds, which makes it easier to improve the adhesion of the pigment to fabrics and the abrasion resistance.

[0079] Examples of the styrene-(meth)acrylic copolymer include a styrene-(meth)acrylic acid copolymer and a styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer. Examples of the (meth)acrylic acid ester include benzyl (meth)acrylate, cyclohexyl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, lauryl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 2-ethylhexyl carbitol (meth)acrylate, phenol EO-modified (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate.

[0080] Urethane resins are polymers obtained by reacting polyols with polyisocyanates. Examples of polyols include polypropylene glycol, polyethylene glycol, polytetramethylene glycol, poly(ethylene adipate), poly(diethylene adipate), poly(propylene adipate), poly(tetramethylene adipate), poly(hexamethylene adipate), poly-ε-caprolactone, poly(hexamethylene carbonate), and silicone polyols. Examples of isocyanates include tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4-diphenylmethane diisocyanate, isophorone diisocyanate, and tetramethylxylylene diisocyanate.

[0081] The Tg of the water-dispersible resin is not particularly limited, but is preferably low from the viewpoint of preventing the fabric from becoming hard even after image formation and making it easier to maintain the texture. The Tg of the water-dispersible resin can be, for example, −30 to 100° C., and preferably −10 to 50° C.

[0082] The acid value of the water-dispersible resin is not particularly limited, but from the viewpoint of improving dispersion stability, it is preferably 44 mg KOH / g or more, more preferably 60 mg KOH / g or more. The upper limit of the acid value can be, for example, 110 mg KOH / g. The acid value can be measured by the same method as above.

[0083] The average particle size of the water-dispersible resin is not particularly limited, but from the viewpoint of preventing nozzle clogging of the inkjet head, it is preferably 300 nm or less, and more preferably 130 nm or less. The average particle size of the water-dispersible resin can be measured by laser diffraction / scattering particle size distribution measurement.

[0084] The content of the water-dispersible resin is preferably 1 to 15% by mass relative to the ink. When the content of the water-dispersible resin is 1% by mass or more, the viscosity of the ink is easily increased to a moderate level, which not only improves the ejection stability but also improves the adhesion of the resulting image to the fabric and the abrasion resistance. When the content of the water-dispersible resin is 15% by mass or less, the viscosity of the ink does not become too high, making it less likely to cause nozzle clogging and the like. From the same perspective, the content of the water-dispersible resin is more preferably 2 to 10% by mass relative to the ink.

[0085] (additives) Examples of the additives include a neutralizing agent, a surfactant, an antiseptic, an antifungal agent, and the like.

[0086] For example, the ink may further contain a neutralizing agent. The neutralizing agent may be a known basic compound, such as sodium hydroxide, potassium hydroxide, ammonia, or triethylamine. The inclusion of a neutralizing agent in the ink can appropriately promote dissociation of anionic groups, such as carboxy groups, contained in the pigment dispersant, thereby further improving the dispersibility of the pigment dispersion.

[0087] The surfactant can reduce the surface tension of the ink and increase the wettability of the ink to the fabric. The type of surfactant is not particularly limited, but can be, for example, an acetylene glycol surfactant, a silicone surfactant, a fluorine surfactant, or the like.

[0088] Examples of the preservative or antifungal agent include aromatic halogen compounds (eg, Preventol CMK), methylene dithiocyanate, halogen-containing nitrogen-sulfur compounds, 1,2-benzisothiazolin-3-one (eg, PROXEL GXL), and the like.

[0089] 2-2. Processing solution The treatment liquid contains a salt of a phosphorus-containing acid and an aqueous solvent, and preferably further contains a polycarboxylic acid.

[0090] 2-2-1. Phosphorus-containing acid salts The salt of the phosphorus-containing acid functions as a crosslinking catalyst for the above-mentioned crosslinking esterification reaction.

[0091] Examples of phosphorus-containing acids include hypophosphorous acid and phosphorous acid, with hypophosphorous acid being preferred. Examples of salts include alkali metal salts and ammonium salts, with alkali metal salts being preferred. Examples of alkali metal salts include potassium salts and sodium salts, with sodium salts being preferred.

[0092] Specific examples of the salt of a phosphorus-containing acid include sodium hypophosphite, potassium hypophosphite, ammonium hypophosphite, etc. Among these, sodium hypophosphite is preferred from the viewpoint of more easily accelerating the above-mentioned crosslinking esterification reaction.

[0093] The content of the phosphorus-containing acid salt in the treatment liquid is not particularly limited, but is preferably 0.5 to 5.0% by mass relative to the treatment liquid. When the content of the phosphorus-containing acid salt is 1% by mass or more, the crosslinking esterification reaction between the hydroxyl groups on the fabric and the carboxyl groups of the pigment dispersant can be further promoted. On the other hand, when the content of the phosphorus-containing acid salt is 5.0% by mass or less, the texture is less likely to be impaired. From the same viewpoint, the content of the phosphorus-containing acid salt is more preferably 0.1 to 3.0% by mass.

[0094] 2-2-2. Polycarboxylic acids The polycarboxylic acid can promote a crosslinking esterification reaction between the hydroxyl groups on the fabric and the carboxyl groups of the pigment dispersant due to the catalytic action of the phosphorus-containing acid salt. This makes it easier to form a covalent bond between the pigment dispersion and the fabric. Furthermore, the carboxyl groups of the polycarboxylic acid itself can also bond with the hydroxyl groups of the fabric. This allows the polycarboxylic acid to form a high-order network structure on the fabric together with the pigment dispersion. As a result, fastness can be further improved. The number of carbon atoms in the polycarboxylic acid is not particularly limited, but is preferably 2 to 10, and more preferably 2 to 5.

[0095] Examples of polycarboxylic acids include hydroxy acids such as malic acid, tartaric acid, and citric acid; and organic acids such as malonic acid, succinic acid, and glutaric acid. Among these, dicarboxylic or tricarboxylic acids are preferred, dicarboxylic or tricarboxylic acids having a hydroxyl group are more preferred, and one or more selected from the group consisting of citric acid, tartaric acid, and malic acid are even more preferred. Among these, tricarboxylic acids having a hydroxyl group, such as citric acid, are particularly preferred from the viewpoint of further accelerating the crosslinking esterification reaction and further improving fixability and fastness.

[0096] The content of polycarboxylic acid in the treatment liquid is not particularly limited, but is preferably 0.1 to 5.0% by mass relative to the treatment liquid. When the content of polycarboxylic acid is 0.1% by mass or more, the crosslinking reaction can be further enhanced, further accelerating the crosslinking esterification reaction between the hydroxyl groups on the fabric and the carboxyl groups of the pigment dispersant. On the other hand, when the content of polycarboxylic acid is 5.0% by mass or less, the texture, wet rub fastness, and wash fastness are less likely to be impaired. This is presumably because the image-formed product is not too hygroscopic, and the carboxyl groups of the polycarboxylic acid and the carboxyl groups of the pigment dispersant are less likely to compete with each other for the hydroxyl groups on the fabric, thereby less compromising the fixability of the pigment dispersion. From the same perspective, the content of polycarboxylic acid is more preferably 0.5 to 5% by mass, and even more preferably 1.0 to 3.0% by mass.

[0097] The content of the polycarboxylic acid in the treatment liquid is preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the salt of the phosphorus-containing acid.

[0098] 2-2-3. Water-based solvents The aqueous solvent preferably contains water and further contains a water-soluble organic solvent.

[0099] The water content is, for example, 20 to 70% by mass, and preferably 30 to 60% by mass, based on the treatment liquid.

[0100] The water-soluble organic solvent may be the same as that used in ink. The content of the water-soluble organic solvent in the treatment liquid is, for example, 20 to 70% by mass, and preferably 30 to 60% by mass.

[0101] 2-2-4. Other ingredients The treatment liquid may further contain, as necessary, a compound having a cationic group and various additives. The various additives may be the same as those used in the ink.

[0102] A compound having a cationic group can interact or react with an anionic group such as a carboxyl group of a pigment dispersant in an ink. This electrical interaction can facilitate aggregation of the pigment.

[0103] Examples of the cationic group in the compound having a cationic group include a secondary amino group, a tertiary amino group, a quaternary ammonium base, etc. Examples of the compound having a cationic group include a cationic resin and a cationic surfactant, and a cationic resin is preferred.

[0104] Examples of cationic resins include cationic urethane resins, cationic olefin resins, and cationic alkylamine resins. Examples of commercially available products include MPT-60 (manufactured by Mitsubishi Pencil Co., Ltd.), Unisense KHE100L (manufactured by Senka Co., Ltd.), and MZ477 (urethane resin, manufactured by Takamatsu Oil & Fat Co., Ltd.). Among them, the cationic alkylamine resins MPT-60 and Unisense KHE100L (manufactured by Senka Co., Ltd.) are preferred from the viewpoint of more easily interacting or reacting with the block copolymer. [Example]

[0105] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0106] 1. Ink Preparation 1-1. Preparation of copolymer (pigment dispersant) <Preparation of Block Copolymer P-1 (ABA Type)> A reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, and a nitrogen inlet tube was charged with 207 parts by mass of tripropylene glycol monomethyl ether, 17.6 parts by mass of benzyl methacrylate (BzMA), 29.7 parts by mass of 2-ethylhexyl methacrylate (2EHMA), 1.0 part by mass of methacrylic acid (MAA), 2.0 parts by mass of iodine, 4.0 parts by mass of 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (AMDV), and 0.08 parts by mass of diphenylmethane (DPM), and the mixture was polymerized at 40°C for 5 hours to obtain polymer chain B, which would become a hydrophobic block.

[0107] To the reaction solution, 25.2 parts by mass of cyclohexyl methacrylate (CHMA), 10.0 parts by mass of methyl methacrylate (MMA), and 8.6 parts by mass of MAA were added, and polymerization was carried out for 3 hours to form polymer chain A1, which would become a hydrophilic block, thereby obtaining an AB-type block copolymer consisting of polymer chain A1 and polymer chain B.

[0108] To the reaction solution, 4.3 parts by mass of BzMA and 8.6 parts by mass of MAA were added, and polymerization was carried out for 2 hours to form polymer chain A2, which would become a hydrophilic block, thereby obtaining an ABA type block copolymer consisting of polymer chain A1, polymer chain B, and polymer chain A2.

[0109] After cooling to room temperature, a homogenized aqueous solution of 8.0 parts by weight of sodium hydroxide and 199 parts by weight of ion-exchanged water was added to neutralize the mixture. The solids content was adjusted by adding ion-exchanged water to obtain an aqueous solution of an ABA block copolymer with a solids content of 30%. The resulting block copolymer had a weight-average molecular weight of 12,000, a PDI of 1.36, and an acid value of 113 mgKOH / g.

[0110] <Preparation of Random Copolymer P-2> A reaction vessel equipped with a dropping device, thermometer, water-cooled reflux condenser, and stirrer was charged with 100 parts by weight of ion-exchanged water. Under a nitrogen atmosphere at 70°C, 0.4 parts by weight of the polymerization initiator ammonium persulfate was added. A monomer solution containing 70 parts by weight of styrene, 19 parts by weight of methyl acrylate, 31 parts by weight of MMA, and 20 parts by weight of n-butyl acrylate was added dropwise to the reaction vessel and reacted to produce a polymer. The mixture was then filtered through a 0.3 μm filter, and the solids content was adjusted by adding ion-exchanged water to obtain emulsion-state resin particles with a solids content of 30%. The weight-average molecular weight of the resulting random copolymer was 8,800.

[0111] 1-2. Preparation of pigment dispersion <Preparation of Pigment Dispersion A-1> 18.0 parts by mass of REGAL330R (a black pigment manufactured by Cabot Corporation) was mixed with 45.0 parts by mass of a 30% solids aqueous solution of block copolymer P-1 (pigment dispersant), 20 parts by mass of propylene glycol, and 17.0 parts by mass of ion-exchanged water. The mixture was then dispersed using a sand grinder filled with 50% by volume of zirconia beads with an average particle size of 0.5 mm to prepare pigment dispersion A-1 with a pigment content of 18.0% by mass.

[0112] <Preparation of Pigment Dispersions A-2 to A-5> Pigment Dispersions A-2 to A-5 were prepared in the same manner as Pigment Dispersion A-1, except that the amounts of pigment and pigment dispersant were adjusted to the amounts shown in Table 1.

[0113] [Table 1]

[0114] 1-3. Preparation of water-based ink <Preparation of Water-Based Ink 1-1> The following components were mixed to a total amount of 100 parts by mass to prepare water-based ink 1-1. Pigment dispersion A-1: ​​10.0 parts by mass Superflex 300: Daiichi Kogyo Seiyaku Co., Ltd. (binder resin): 8.0 parts by mass Glycerin (solvent): 10.0 parts by mass Ethylene glycol (EG) (solvent): 25 parts by mass Proxel GXL(S) (preservative): 0.1 parts by weight Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 2.5 parts by mass Ion exchange water: remaining amount

[0115] <Preparation of Water-Based Inks 1-2 to 1-5> Water-based inks 1-2 to 1-5 were obtained in the same manner as water-based ink 1-1, except that the content or type of pigment dispersant was changed as shown in Table 2 and the amount of ion-exchanged water was adjusted so that the total amount was 100 parts by mass.

[0116] Table 2 shows the compositions of the main components of the resulting water-based inks 1-1 to 1-5.

[0117] [Table 2]

[0118] 2. Preparation of Treatment Solutions 2-1. Crosslinking catalyst Sodium hypophosphite Potassium hypophosphite Ammonium hypophosphite

[0119] 2-2. Polycarboxylic acids Citric acid (C6, trivalent, hydroxyl group present) Malonic acid (C3, divalent, no hydroxyl group) Succinic acid (C4, divalent, no hydroxyl group) Glutaric acid (C5, divalent, no hydroxyl group) Malic acid (C4, divalent, hydroxyl group present) Tartaric acid (C4, divalent, hydroxyl group present)

[0120] 2-3. Preparation of treatment solution <Preparation of Processing Solution 2-1> The following components were mixed to a total amount of 100 parts by mass to prepare treatment liquid 2-1. Sodium hypophosphite (crosslinking catalyst): 2.0 parts by mass Citric acid (polycarboxylic acid): 3.0 parts by mass Vinyl ether crosslinking agent (manufactured by Tokyo Chemical Industry Co., Ltd.): 0.50 parts by mass Ethylene glycol (EG, solvent): 20 parts by mass Propylene glycol (PG, solvent): 10 parts by mass Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 0.1 parts by mass Proxel GXL(S) (Lonza, preservative): 0.5 parts by weight Ion exchange water: remaining amount

[0121] <Preparation of Treatment Solutions 2-2 to 2-17> Treatment solutions 2-2 to 2-17 were prepared in the same manner except that the composition of the treatment solution was changed as shown in Table 3 and the amount of ion-exchanged water was adjusted so that the total amount was 100 parts by mass.

[0122] Table 3 shows the compositions of the main components of the resulting treatment solutions 2-1 to 2-17.

[0123] [Table 3]

[0124] 3. Image formation and evaluation [Example 1] (1) Applying treatment liquid and ink A 100% cotton fabric (white) was prepared. An inkjet printer having an inkjet head (Konica Minolta Head KM1024iMAE) was prepared as an image forming apparatus, and treatment liquid 2-1 and ink 1-1 were set in this apparatus. The pretreatment liquid and ink were both applied wet-on-wet, using an inkjet method and a multi-pass method. Specifically, the treatment liquid 2-1 was applied to the surface of the fabric from the inkjet head at a rate of 15 g / m 2The amount of the solution (including the solvent) was Next, ink 1-1 was sprayed from the inkjet head at a rate of 15 g / m 2 so as to overlap with the treatment liquid 2-1 applied to the fabric. 2 The coating was applied wet-on-wet so that the amount of coating (including the solvent) was 100%. These pretreatment and ink application processes were repeated. A solid image was formed on the cotton fabric with a print width of 100 nm x 100 nm and a resolution of 720 dpi x 720 dpi. dpi represents the number of ink droplets (dots) per 2.54 cm. The ejection frequency was 22.4 kHz.

[0125] (2) Drying and Fixation Thereafter, the fabric to which the treatment liquid and ink had been applied was dried in a belt conveying dryer at 150° C. for 3 minutes, thereby obtaining an image-formed product.

[0126] [Examples 2 to 18, Comparative Examples 1 and 2] Image formation was carried out in the same manner as in Example 1, except that at least one of the type of treatment liquid and the type of ink was changed as shown in Table 4.

[0127] [evaluation] The resulting image-formed product was evaluated as follows.

[0128] (Wet rubbing fastness) The wet rubbing fastness of the obtained image-formed product was evaluated using a crock meter (rubbing tester type I) in accordance with JIS L 0849. Specifically, an image of the surface of the image-formed product was captured with a scanner, and the image was processed to quantify the staining level of the white cloth, which was then evaluated according to the following criteria. 5: Compared to when no pretreatment is used, contamination of white fabric is reduced by more than 90%. 4: Compared to when no pretreatment is used, contamination of white fabric is reduced by 60% to less than 90% 3: Compared to when no pretreatment is used, contamination of white fabric is reduced by 30% or more but less than 60% 2: Compared to when no pretreatment is used, contamination of white fabric is reduced by 10% or more but less than 30% 1: Compared to no pretreatment, the contamination of white fabric is reduced by less than 10%. A score of 3 or higher was considered acceptable.

[0129] (adhesion) A tape peeling test was carried out on the solid image of the image-formed product, and the fixability of the image was evaluated according to the following criteria. 5: The area of ​​the image peeled off by the tape is less than 1% of the area of ​​the solid image. 4: The area of ​​the image peeled off by the tape is 1% or more but less than 3% of the area of ​​the solid image. 3: The area of ​​the image peeled off by the tape is 3% or more but less than 5% of the area of ​​the solid image. 2: The area of ​​the image peeled off by the tape is 5% or more but less than 10% of the area of ​​the solid image. 1: The area of ​​the image peeled off by the tape is 10% or more of the area of ​​the solid image. A score of 3 or higher was considered acceptable.

[0130] (washing fastness) The resulting image-formed products were evaluated for color fading by comparing the image-formed products after one wash (washing with water) in a household washing machine with the image-formed products that had not been washed, and were evaluated based on the following evaluation criteria. A: No color fading after rinsing B: There is little or no color fading after rinsing, and it is at a level that is completely acceptable for practical use. be C: There is some discoloration after rinsing, but it is not a problem for practical use. D: Discoloration after rinsing is significant and at a level that is problematic for practical use. Grades of C or higher were considered to be within the acceptable range.

[0131] (Texture) The texture of the image-formed product and the fabric was evaluated sensorily by touching with the fingers. was carried out based on the criteria. A: The original softness of the fabric is maintained, and it is almost the same as before the image formation. B: It is a little stiffer than before the image formation, but the texture of the fabric is not damaged and it is actually No problem in use C: The paper is harder than before image formation, the texture of the fabric is damaged, and there is a problem with practical use. The level at which If it was B or above, it was considered to be within the acceptable range.

[0132] Table 4 shows the evaluation results of Examples 1 to 18 and Comparative Examples 1 and 2.

[0133] [Table 4]

[0134] As shown in Table 4, in Examples 1 to 18, in which images were formed using a treatment liquid containing an alkali metal hypophosphite as a crosslinking catalyst and an ink using a pigment dispersant containing a carboxy group, good wet rub fastness, wash fastness, and fixability were obtained while maintaining the texture.

[0135] In contrast, Comparative Example 2, which used an epoxy resin as a crosslinking agent, showed a deterioration in texture, and Comparative Example 1, which used a treatment liquid containing hypophosphorous acid, not a salt, showed poor fixability, washing fastness, and texture.

[0136] [Example 19] A treatment liquid was applied to the entire printing area on the surface of the fabric by inkjet printing, and then the fabric was dried for 3 minutes at 150° C. using a belt-conveying dryer. Image formation was then carried out in the same manner as in Example 1, except that ink was then applied by inkjet printing to the entire area where the pretreatment liquid had been applied, forming a solid image.

[0137] The evaluation results of Example 19 are shown in Table 5. For comparison, the results of Example 1 are also shown.

[0138] [Table 5]

[0139] As shown in Table 5, by applying the treatment liquid and ink wet-on-wet, the washing fastness, wet rub fastness, and fixability of the resulting image-formed product are all improved.

[0140] [Example 20] Image formation was carried out in the same manner as in Example 1, except that the treatment liquid was applied to the entire printing area using an inkjet method, and then, before the treatment liquid had completely dried, ink was applied to the area to which the treatment liquid had been applied using an inkjet method to form a solid image.

[0141] The evaluation results of Example 20 are shown in Table 6. For comparison, the results of Example 1 are also shown.

[0142] [Table 6]

[0143] As shown in Table 6, simultaneous ejection of the pretreatment liquid and ink results in improved fixation and washing fastness of the resulting image. This is presumably because the components of the treatment liquid and the ink are more easily mixed, further accelerating the crosslinking esterification reaction by the salt of the phosphorus-containing acid. [Industrial Applicability]

[0144] According to the present invention, it is possible to provide an image forming method capable of forming an image having high fastness without causing deterioration in texture.

Claims

1. applying a treatment liquid onto a fabric containing fibers having hydroxyl groups; applying ink to a fabric containing fibers having hydroxyl groups by an inkjet method; Including, The ink includes a pigment, a pigment dispersant containing a carboxy group and adsorbed to the surface of the pigment, and an aqueous solvent; The treatment liquid contains a salt of a phosphorus-containing acid and an aqueous solvent. Image forming method.

2. The salt of the phosphorus-containing acid includes an alkali metal salt of the phosphorus-containing acid. The image forming method according to claim 1 .

3. the content of the salt of a phosphorus-containing acid in the treatment solution is 0.1 to 5.0% by mass relative to the treatment solution; The image forming method according to claim 1 .

4. The treatment liquid further contains a polycarboxylic acid. The image forming method according to claim 1 .

5. The polycarboxylic acid is selected from the group consisting of citric acid, tartaric acid, and malic acid. The image forming method according to claim 4.

6. the content of the polycarboxylic acid in the treatment liquid is 0.1 to 5.0% by mass relative to the treatment liquid; The image forming method according to claim 4 or 5.

7. a mass ratio X / Y of an amount X of the salt of a phosphorus-containing acid attached to the fabric and an amount Y of the pigment dispersant attached to the fabric is 1 to 50; The image forming method according to claim 1 .

8. The pigment dispersant contains a polymer containing a structural unit derived from a carboxy group-containing monomer. The image forming method according to claim 1 .

9. In the step of applying the ink, applying the ink wet-on-wet onto the fabric to which the treatment liquid has been applied; The image forming method according to claim 1 .

10. The fabric comprises cotton. The image forming method according to claim 1 .

Images