Image forming method

Abstract

To provide an image forming method capable of forming an image having high friction fastness on a fabric while suppressing density unevenness and color unevenness even for a fabric treated off-line.SOLUTION: The image forming method includes a step of preparing a fabric in a dry state to which a cationic coagulant is attached, and a step of applying an ink containing a pigment, an anionic block copolymer, a silicone acrylic resin, and water onto the fabric by an ink jet method. The block copolymer contains a hydrophilic block A and a hydrophobic block B.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 the use of pigment inks, which can omit post-processing such as a washing step for washing away dye that has not dissolved or reacted, is being considered.

[0004] Pigment inks exhibit high color development by retaining pigment particles on the surface of the fabric, but tend to have lower fixation of pigment particles and inferior rub fastness compared to dye inks. Therefore, studies have been conducted to improve the fixation of pigment particles and rub fastness by performing pretreatment or posttreatment on the fabric before applying the ink, in which an aggregating agent is applied to the fabric to aggregate the pigment dispersion.

[0005] For example, Patent Document 1 discloses an image forming method including a step of applying a pretreatment liquid containing a flocculant to a fabric, and a step of applying an ink containing a pigment to the fabric to which the pretreatment liquid has been applied by an inkjet method. In this document, organic acids, cationic polymers, etc. are described as flocculants contained in the pretreatment liquid.

[0006] Patent Document 2 discloses an image forming method including a step of applying a pigment-containing ink to a fabric by an inkjet method and a step of applying a treatment liquid containing a resin emulsion onto the fabric to which the ink has been applied. In the above document, a cationic resin emulsion or the like is described as the resin emulsion contained in the treatment liquid.

[0007] Patent Document 3 discloses, as a dispersant for dispersing pigments, a block copolymer including an A block containing structural units derived from a (meth)acrylate having an aromatic group or a (meth)acrylate having a cyclic alkyl group, and a B block containing structural units derived from (meth)acrylic acid or a (meth)acrylate having a carboxy group. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-180815 [Patent Document 2] Patent Publication No. 2021-95497 [Patent Document 3] Patent Publication No. 2021-98835 Summary of the Invention [Problem to be solved by the invention]

[0009] In the image forming method described above, the process of applying a treatment liquid to a fabric and attaching a flocculant (pretreatment process) is generally carried out online. However, in some cases, the pretreatment process may be carried out offline, for example, when the treatment liquid is required to have a function other than flocculation.

[0010] However, when the pretreatment step is performed offline, it tends to be difficult to obtain abrasion fastness of the image-formed product compared to when it is performed online. This is thought to be because when the pretreatment step is performed offline, the ink is applied to the fabric in a dry state, and therefore interaction between the flocculant attached to the fabric and the pigment dispersion in the ink is less likely to occur compared to when the ink is applied online to the fabric in a wet state.

[0011] In response to this problem, the inventors have found that by using a block copolymer containing two hydrophilic blocks A located at both ends of the molecule and a hydrophobic block B located between them as a pigment dispersant, it is possible to form an image with high friction resistance even on a dry fabric. However, the use of this block copolymer has also revealed a new problem: the resulting image is prone to uneven density and color.

[0012] The present invention has been made in consideration of the above-mentioned problems, and aims to provide an image forming method that can form an image with high friction resistance on fabric while suppressing uneven density and color, even on fabric that has been processed offline. [Means for solving the problem]

[0013] The present invention relates to the following image forming method.

[0014] [1] An image forming method comprising the steps of: preparing a dry fabric having a cationic flocculant attached thereto; and applying, by an inkjet method, onto the fabric an ink containing a pigment, an anionic block copolymer, a silicone acrylic resin, and an aqueous solvent, wherein the anionic block copolymer contains a hydrophilic block A and a hydrophobic block B. [2] The image forming method according to [1], wherein the step of preparing the fabric includes a step of applying a treatment liquid containing a cationic flocculant and an aqueous solvent to the fabric, and a step of drying the fabric to which the treatment liquid has been applied. [3] The image forming method according to [2], wherein in the drying step, the fabric is dried until the remaining amount of the aqueous solvent in the fabric is 20% by mass or less of the total amount of the aqueous solvent applied to the fabric. [4] The image forming method according to any one of [1] to [3], wherein the anionic block copolymer contains two hydrophilic blocks A arranged at both ends of the molecule and a hydrophobic block B arranged between the two hydrophilic blocks A. [5] The image forming method according to any one of [1] to [4], wherein the silicone acrylic resin contains a structural unit X derived from a polyorganosiloxane having a radical polymerizable group and a structural unit Y derived from a (meth)acrylic acid ester, and the content of the structural unit X is 80% by mass or more and 99% by mass or less based on the total amount of the structural unit X and the structural unit Y. [6] The image forming method according to any one of [1] to [5], wherein the weight average molecular weight of the silicone acrylic resin is 1,000 or more and 500,000 or less. [7] The image forming method according to any one of [1] to [6], wherein the content of the silicone acrylic resin in the ink is 0.2% by mass or more and 10% by mass or less relative to the ink. [8] The image forming method according to any one of [1] to [7], wherein the ink further contains a water-dispersible resin different from the anionic block copolymer. [9] The image forming method according to any one of [1] to [8], further comprising a step of applying a second treatment liquid containing a water-dispersible resin and an aqueous solvent onto the fabric to which the ink has been applied.

[10] The image forming method according to [8] or [9], wherein the anionic water-dispersible resin includes a (meth)acrylic resin or a urethane resin.

[11] The image forming method according to [9], wherein at least one of the ink and the second treatment liquid further contains a crosslinking agent.

[12] The image forming method according to any one of [1] to

[11] , wherein the aggregating agent contains a polyvalent metal salt or a compound having a cationic group.

[13] The image forming method according to

[12] , wherein the compound having a cationic group includes a cationic resin. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an image forming method that can form an image with high abrasion resistance on fabric while suppressing uneven density and color even on fabric that has been processed offline. DETAILED DESCRIPTION OF THE INVENTION

[0016] As described above, a block copolymer containing two hydrophilic blocks A at both ends of the molecule and a hydrophobic block B between them as a pigment dispersant has a hydrophilic and hydrophobic portion in a block configuration, which makes it easier for the block copolymer to interact with the cationic flocculant attached to the fabric at multiple points and provides stronger bonding strength than a random copolymer. Therefore, inks containing the block copolymers can form images with high abrasion resistance even on dry fabrics that have been processed offline. On the other hand, a new problem has been found in that images obtained using inks containing the above-mentioned block copolymers are prone to uneven density and color. This is presumably because the strong binding force between the above-mentioned block copolymers and the cationic flocculant on the fabric causes the pigment dispersion containing the above-mentioned block copolymers to aggregate before the ink droplets have a chance to sufficiently wet and spread on the fabric.

[0017] In response to this, the present inventors conducted extensive research and found that density unevenness and color unevenness can be suppressed by further incorporating a silicone acrylic resin into the ink containing the block copolymer. That is, the inclusion of a silicone acrylic resin in the ink makes the ink more easily wetted and spreadable. This is thought to enable ink droplets to quickly wet and spread on the fabric while allowing the pigment dispersion containing the block copolymer to quickly aggregate, thereby reducing density unevenness and color unevenness. Furthermore, silicone acrylic resins with siloxane as the main chain can prevent the ink dispersion stability and inkjet ejection properties from deteriorating as compared to silicone surfactants or resins with acrylic polymer as the main chain.

[0018] That is, an image forming method according to one embodiment of the present invention includes the steps of: 1) preparing a dry fabric having a cationic flocculant attached thereto (hereinafter also referred to as a treated fabric); and 2) applying an ink containing a pigment, an anionic block copolymer, a silicone acrylic resin, and water onto the fabric by an inkjet method.

[0019] In the following description of the image forming method, the ink used in the image forming method, and the treatment liquid (first treatment liquid) and second treatment liquid for preparing the treated fabric will be described.

[0020] 1. Ink, first treatment liquid, and second treatment liquid 1-1.Ink The ink used in this embodiment is a water-based ink, and contains a pigment, an anionic block copolymer, a silicone acrylic resin, and a water-based solvent.

[0021] 1-1-1. Pigments The pigment is not particularly limited, but examples thereof include organic pigments or inorganic pigments having the following numbers listed in the Color Index.

[0022] 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.

[0023] 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.

[0024] Examples of green pigments include Pigment Green 7, 26, 36, and 50.

[0025] Examples of yellow pigments include Pigment Yellow 1, 3, 12, 13, 14, 17, 34, 35, 37, 55, 74, 81, 83, 93, 94, 95, 97, 108, 109, 110, 137, 138, 139, 153, 154, 155, 157, 166, 167, 168, 180, 185, and 193.

[0026] Examples of black pigments include Pigment Black 7, 28, and 26.

[0027] 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, 5000P, Chrome Fine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Chrome Fine Black A-1103, Seika Fast Yellow 10GH, A-3, 2035, 2054, 2200, 2270, 2300, 2400(B), 2500, 2600, ZAY-260, 2700(B), 2770, Se Squidfast Red 8040, C405(F), CA120, LR-116, 1531B, 8060R, 1547, ZAW-262, 1537B, GY, 4R-4016, 3820, 3891, ZA-215, Seikafast Carmine 6B1476T-7, 1483LT, 3840, 3870, Seikafast Bordeaux 10B-430, Seikalite Rose R40, Seikalite Violet B800, 7805, Seikafast Maroon 460N, Seikafast Orange 900, 2900, Seikalite Blue C718, A612, Cyanine Blue 4933M, 4933GN-EP, 4940, 4973 (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.); 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 and Chemicals Co., Ltd.);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 Dye Co., Ltd.); 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 Corporation).

[0028] (self-dispersing pigment) The pigment may be a self-dispersing pigment. A self-dispersing pigment is a pigment particle whose surface is modified with a group having a hydrophilic group. A self-dispersing pigment has pigment particles and hydrophilic groups bonded to the surface of the pigment particles.

[0029] Examples of hydrophilic groups include carboxy groups, sulfonic acid groups, and phosphorus-containing groups, and examples of phosphorus-containing groups include phosphoric acid groups, phosphonic acid groups, phosphinic acid groups, phosphite groups, and phosphate groups.

[0030] Commercially available examples of self-dispersing pigments include Cabot's Cab-0-Jet® 200K, 250C, 260M, and 270V (sulfonic acid group-containing self-dispersing pigments). Other commercially available examples of self-dispersing pigments include Cabot's Cab-0-Jet® 300K (carboxylic acid group-containing self-dispersing pigments) and Cab-0-Jet® 400K, 450C, 465M, 470V, and 480V (phosphate group-containing self-dispersing pigments).

[0031] The pigment content is not particularly limited, but is preferably in the range of 1.5% by mass to 15% by mass of the ink. When the pigment content is 1.5% by mass or more, it is easy to form a high-density image. When the pigment content is 15% by mass or less, the viscosity of the ink does not become too high, so ejection stability is less likely to be impaired. For the same reason, the pigment content is more preferably 5% by mass to 15% by mass of the ink.

[0032] 1-1-2. Anionic block copolymer The anionic block copolymer can function as a pigment dispersant. A pigment dispersant adheres to the surface of a pigment, making it easier to disperse the pigment in water. A pigment with the pigment dispersant attached thereto dispersed in a dispersion medium (such as water) is called a pigment dispersion.

[0033] The anionic block copolymer is a copolymer containing a hydrophilic block A and a hydrophobic block B, preferably a copolymer containing two hydrophilic blocks A arranged at both ends of the molecule and a hydrophobic block B arranged between the two hydrophilic blocks A, and more preferably an ABA block copolymer consisting of two hydrophilic blocks A and a hydrophobic block B arranged between them.

[0034] The hydrophilic block A contains a site that interacts or reacts with the cationic flocculant. Examples of the interaction include electrical bonding and hydrogen bonding, with electrical bonding being preferred. The hydrophobic block B contains a site that adsorbs to the pigment.

[0035] Random copolymers do not have blocks containing many sites that interact or react with flocculants, and therefore are less likely to interact or react with flocculants. 。

[0036] In contrast, copolymers containing a hydrophilic block A and a hydrophobic block B have blocks containing many sites that interact or react with flocculants, making them more likely to interact or react with flocculants. In particular, copolymers containing two hydrophilic blocks A at both ends of the molecule and a hydrophobic block B located between the two hydrophilic blocks A (e.g., ABA-type block copolymers) contain blocks at both ends of the molecule containing many sites that interact or react with flocculants. Because these blocks are present at at least two locations on both ends of the molecule, there are many bonding points available for bonding with fabric, making the bonding with the fabric stronger. This improves adhesion to the fabric and increases friction resistance. Furthermore, because the copolymer can bond with the fabric intermittently at multiple bonding points, the fabric is less likely to become hard than if the copolymer were continuously bonded at a single bonding point.

[0037] The "hydrophilic block A" is an anionic block that enhances affinity with the aqueous solvent contained in the pigment ink and contains a site that interacts or reacts with the cationic flocculant attached to the fabric, and refers to the block that has the highest affinity with water among the blocks constituting the copolymer. The number of hydrophilic blocks is preferably two.

[0038] The hydrophilic block A contains a structural unit derived from a monomer having a hydrophilic anionic functional group (hereinafter referred to as "hydrophilic monomer"). Examples of the hydrophilic anionic functional group include a hydroxyl group, a carboxyl group, and a sulfonic acid group.

[0039] Examples of the hydrophilic monomer constituting the hydrophilic block A include a monomer containing a hydrophilic anionic functional group and an unsaturated double bond, and examples thereof include: Monomers containing a carboxy group or an acid anhydride group, such as unsaturated polycarboxylic acids such as (meth)acrylic acid and maleic acid, and maleic anhydride; Monomers containing sulfonic acid groups, such as styrenesulfonic acid and 4-(methacryloyloxy)butylsulfonic acid Among these, the hydrophilic monomer is preferably (meth)acrylic acid from the viewpoint of imparting appropriate water solubility to the hydrophilic block A.

[0040] The content of the structural units derived from hydrophilic monomers in the hydrophilic block A should be higher than the content of the structural units derived from hydrophilic monomers in the hydrophobic block B. Specifically, the content of the structural units derived from hydrophilic monomers in the hydrophilic block A is preferably 5% by mass or more relative to 100% by mass of the hydrophilic block A. When the content of the structural units derived from hydrophilic monomers is 5% by mass or more, not only is the dispersibility in aqueous solvents more likely to be improved, but the structural units also more likely to interact or react with the cationic resin, making it easier to improve the rub fastness. From the same viewpoint, the content is more preferably 10% by mass or more and 40% by mass or less.

[0041] 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. Among these, C2 or higher alkyl esters such as butyl (meth)acrylate are preferred. This is because the glass transition temperature of the anionic block copolymer is low, and the fabric is less likely to become stiff. However, the other monomers do not include the hydrophobic monomers described below.

[0042] 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 preferably one.

[0043] The hydrophobic block B contains a structural unit derived from a monomer having a hydrophobic functional group (hereinafter referred to as "hydrophobic monomer"). Examples of the monomer having a hydrophobic functional group include a monomer containing an aromatic ring group or an alicyclic hydrocarbon group.

[0044] Examples of monomers containing aromatic ring groups include: (meth)acrylates having an aromatic ring group, such as benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate; Aromatic monomers such as styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, or 1-vinylnaphthalene Monomers having an aromatic ring group with 6 to 15 carbon atoms are preferred.

[0045] Examples of 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, or dicyclopentenyloxyethyl (meth)acrylate Monomers having an alicyclic alkyl group having 6 to 15 carbon atoms are preferred.

[0046] Of these, from the viewpoint of improving the adsorption to the pigment, the hydrophobic monomer is preferably a monomer having an aromatic ring group having 6 to 15 carbon atoms, such as styrene.

[0047] The content of structural units derived from hydrophobic monomers in the hydrophobic block B is preferably 80% by mass or more relative to the hydrophobic block B. When the content is 80% by mass or more, the adsorption to pigments is likely to be enhanced. From the same viewpoint, the content is more preferably more than 90% by mass, and even more preferably 95% by mass or more.

[0048] The hydrophobic block B may further contain structural units derived from monomers other than hydrophobic monomers. Examples of the other monomers include the above-mentioned other monomers and hydrophilic monomers. However, when the hydrophobic block B contains structural units derived from hydrophilic monomers, the content of the structural units derived from hydrophilic monomers in the hydrophobic block B is lower than that in the hydrophilic block A. Specifically, the content of the structural units derived from hydrophilic monomers is preferably 20% by mass or less, more preferably less than 10% by mass, and even more preferably 5% by mass or less, relative to the content of the structural units derived from hydrophilic monomers in the hydrophobic block B. In other words, of the two blocks, hydrophilic block A and hydrophobic block B, the content of the structural units derived from hydrophilic monomers (molar number of hydrophilic functional groups) in the hydrophobic block B is the lowest.

[0049] The content of the hydrophobic block B in the anionic block copolymer is preferably 20% to 80% by mass, more preferably 20% to 50% by mass, based on the total mass of the block copolymer. When the content is 20% by mass or more, the content of the hydrophilic block A is low (or the molecular weight is small), which makes it easier to suppress crosslinking and aggregation. When the content is 80% by mass or less, the content of the hydrophilic block A is high (or the molecular weight is large), which makes it easier to increase the affinity for aqueous solvents.

[0050] When the hydrophilic block is A and the hydrophobic block is B, examples of the anionic block copolymer structure include AB type, ABA type, ABABA type, etc. Among these, the block copolymer is preferably an ABA type block copolymer consisting of two hydrophilic blocks A located at both ends of the molecule and a hydrophobic block B located between them.

[0051] The types and compositional ratios of monomers in the multiple blocks A contained in the block copolymer may be the same as or different from each other. Furthermore, when the block copolymer contains multiple blocks B, the types and compositional ratios of monomers in the multiple blocks B may be the same as or different from each other. In particular, it is preferable that the two hydrophilic blocks A have the same monomer composition.

[0052] The weight-average molecular weight of the anionic block copolymer is preferably 5,000 to 70,000, and more preferably 7,000 to 30,000. 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 dispersions of pigments to which the anionic pigment dispersant has adhered (which can also be referred to as pigments themselves). The weight-average molecular weight of the anionic block copolymer can be measured in polystyrene equivalent terms by gel permeation chromatography.

[0053] The molecular weight distribution (PDI) (weight average molecular weight (Mw) of the block copolymer) / (number average molecular weight (Mn) of the block copolymer) is preferably 2.0 or less, and more preferably 1.8 or less. A lower PDI means a narrower and more uniform molecular weight distribution, resulting in better dispersibility.

[0054] The acid value of the anionic block copolymer is, for example, preferably 40 mgKOH / g or more and 400 mgKOH / g or less, more preferably 40 mgKOH / g or more and 300 mgKOH / g or less, and even 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 pigment dispersibility. Furthermore, an acid value of 400 mgKOH / g or less can further prevent the hydrophilicity of the pigment dispersant from becoming excessively high, thereby making it less likely that the pigment adsorption property will be impaired. The acid value can be measured in accordance with the measurement method of JIS K0070:1992.

[0055] The content of the anionic block copolymer is preferably 10% by mass or more and 50% by mass or less, and more preferably 20% by mass or more and 40% by mass or less, relative to the pigment. A content of 10% by mass or more can further enhance the dispersibility of the pigment in the pigment dispersion. Furthermore, a content of the pigment dispersant of 50% by mass or less can further suppress an increase in the viscosity of the pigment dispersion due to an excessive amount of pigment dispersant.

[0056] The method for synthesizing the anionic block copolymer is not particularly limited, but for example, it can be obtained by sequentially polymerizing vinyl monomers that constitute the blocks by living radical polymerization.

[0057] 1-1-3. Silicone acrylic resin Silicone acrylic resins can make inks wettable and spreadable on fabrics. Silicone acrylic resins can be copolymers containing a structural unit X derived from a polyorganosiloxane having a radically polymerizable group and a structural unit Y derived from a (meth)acrylic acid ester. Examples of radically polymerizable groups include vinyl groups, allyl groups, (meth)acryloxy groups, and mercapto groups. Silicone acrylic resins can exist in an aqueous medium in the form of dispersed resin particles.

[0058] The copolymer is preferably a graft copolymer in which, for example, a polymer containing structural units derived from polyorganosiloxane having radically polymerizable groups is graft-polymerized with a (meth)acrylic acid ester or the like. Such a graft copolymer has a structure in which the polyorganosiloxane portion forms the trunk and the (meth)acrylic acid ester or the like forms the branches, and is therefore preferred because it is more compatible with the acrylic resin when used in, for example, an ink containing an acrylic resin. The form of copolymerization is not limited to graft copolymerization, and may be random copolymerization or block copolymerization. However, block copolymerization is different from the anionic block copolymer described above.

[0059] The silicone acrylic resin may also have an anionic group, examples of which include a carboxy group, a sulfonic acid group, and a phosphonic acid group.

[0060] Examples of polyorganosiloxanes having a radical polymerizable group include polyorganosiloxanes represented by the following formula (1). [ka]

[0061] In formula (1), R 1 , R 2 and R 3 are each independently a hydrocarbon group having 1 to 10 carbon atoms.

[0062] In formula (1), Y is a radical polymerizable group selected from the group consisting of a vinyl group, an allyl group, and a γ-(meth)acryloxypropyl group.

[0063] In formula (1), X 1 and X 2 are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or -SiR 4 R 5 R 6 The group is represented by the formula: m is an integer of 1 or more and 10,000 or less, and n is an integer of 1 or more. The siloxane chain may be branched.

[0064] In addition, -SiR 4 R 5 R 6 In R 4 and R 5 R are each independently a hydrocarbon group having 1 to 10 carbon atoms. 6 is a radical polymerizable group selected from the group consisting of a vinyl group, an allyl group, and a γ-(meth)acryloxypropyl group, or a hydrocarbon group having 1 to 10 carbon atoms.

[0065] Other polymerizable monomers include (meth)acrylic acid esters. In this specification, (meth)acrylic refers to acrylic, methacrylic, or both.

[0066] The (meth)acrylic acid ester is an alkyl ester, a hydroxyalkyl ester, or an alkoxyalkyl ester of (meth)acrylic acid. Examples of the (meth)acrylic acid ester include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, and isobutyl (meth)acrylate. Other examples of the (meth)acrylic acid ester include 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-octyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. Among these, methyl methacrylate and 2-hydroxyethyl methacrylate are preferred.

[0067] The content of the structural unit X derived from the polyorganosiloxane having a radical polymerizable group in the silicone acrylic resin is preferably 50% by mass or more, more preferably 60% by mass or more and 99% by mass or less, and even more preferably 80% by mass or more and 99% by mass or less, based on the total amount of the structural unit X derived from the polyorganosiloxane having a radical polymerizable group and the structural unit Y derived from a (meth)acrylic acid ester. When the content of the structural unit X is 50% by mass or more, the wettability improvement effect derived from the polysiloxane is more easily achieved. When the content of the structural unit X is 99% by mass or less, the content of the structural unit Y derived from a (meth)acrylic acid ester is sufficient, which more easily increases the affinity with, for example, a water-dispersible resin (e.g., an acrylic resin) that may be contained in the ink or second treatment liquid. The total amount of the structural unit X and the structural unit Y in the silicone acrylic resin may be 50% by mass or more, or may even be 100% by mass, based on the total amount of all structural units in the silicone acrylic resin.

[0068] The silicone acrylic resin may further contain structural units derived from other polymerizable monomers than those mentioned above. Examples of other polymerizable monomers include ethylenically unsaturated carboxylic acids such as (meth)acrylic acid, styrenes, etc. For example, from the viewpoint of exhibiting anionic properties, the silicone acrylic resin may further contain structural units derived from ethylenically unsaturated carboxylic acids such as (meth)acrylic acid.

[0069] The weight-average molecular weight of the silicone acrylic resin is not particularly limited, but is preferably 1,000 to 500,000, more preferably 1,000 to 100,000, and even more preferably 1,000 to 50,000. A weight-average molecular weight of 1,000 or more can further promote wetting and spreading of the ink, thereby further suppressing density unevenness and color unevenness. A weight-average molecular weight of 500,000 or less can further reduce the viscosity of the ink, thereby better maintaining ejection stability and texture. The weight-average molecular weight of the silicone acrylic resin can be measured in polystyrene equivalent terms by gel permeation chromatography.

[0070] The graft copolymerization can be carried out by a known method, for example, by emulsifying and dispersing the polyorganosiloxane represented by formula (1) and a copolymerizable compound such as a (meth)acrylic acid ester in water, and polymerizing them in the presence of a radical polymerization initiator.

[0071] Examples of commercially available silicone acrylic resins include Chaline LC190, Chaline R-170, R170S, Chaline FE-230N, FE-502, and R-170BX (manufactured by Nissin Chemical Industry Co., Ltd.).

[0072] The content of the silicone acrylic resin in the ink is preferably 0.1% by mass or more and 10% by mass or less, and more preferably 0.2% by mass or more and 3.0% by mass or less. A content of 0.1% by mass or more allows the ink to more easily wet and spread on the fabric. This allows the ink to wet and spread while further promoting pigment aggregation by the anionic block copolymer, thereby further reducing density unevenness and color unevenness. Furthermore, a content of the silicone acrylic resin of 10% by mass or less can prevent a decrease in ejection stability and texture.

[0073] From the same viewpoint as above, the mass ratio of the silicone acrylic resin content to the anionic block copolymer content is preferably 1 / 3 or more and 10 / 1 or less, and more preferably 1 / 2 or more and 5 / 1 or less.

[0074] Furthermore, when the ink further contains a water-dispersible resin other than the anionic block copolymer, the mass ratio of the silicone acrylic resin content to the total amount of the silicone acrylic resin and the water-dispersible resin is preferably 1 / 100 or more and 1 / 2 or less, and more preferably 1 / 50 or more and 3 / 10 or less. A mass ratio of 1 / 50 or more can make the ink more easily wet and spread, thereby further suppressing uneven density and color in the resulting image. A mass ratio of 3 / 10 or less can further improve abrasion resistance and further suppress deterioration in texture.

[0075] 1-1-4. Water-based solvents The aqueous solvent preferably contains water and further contains a water-soluble organic solvent, which can further improve ejection stability by inkjet printing.

[0076] The water-soluble organic solvent is not particularly limited as long as it is compatible with water, and examples thereof include polyhydric alcohols (for example, dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, and polypropylene glycol, and trihydric or higher alcohols such as glycerin, trimethylolpropane, and hexanetriol); polyhydric alcohol ethers (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, and diethylene glycol dimethyl ether); ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether); monohydric alcohols (e.g., methanol, ethanol, propanol, pentanol, hexanol, cyclohexanol, 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).

[0077] Furthermore, from the viewpoint of further improving ejection stability by inkjet printing, the water-soluble organic solvent preferably contains a water-soluble organic solvent having a boiling point of 180°C or higher, preferably 190°C or higher, and more preferably 200°C or higher. Examples of water-soluble organic solvents having a boiling point of 180°C or higher include dihydric alcohols and trihydric or higher alcohols. Examples of dihydric alcohols include ethylene glycol (boiling point 197°C), 1,3-butanediol (boiling point 208°C), 1,6-hexanediol (boiling point 223°C), and polypropylene glycol. Examples of trihydric or higher alcohols include glycerin (boiling point 290°C) and trimethylolpropane (boiling point 295°C).

[0078] The content of the water-soluble organic solvent in the ink is, for example, preferably 20% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, based on the ink.

[0079] Similarly, the water content in the ink is preferably, for example, from 20% to 70% by mass, and more preferably from 30% to 60% by mass, based on the ink.

[0080] 1-1-5. Other ingredients The ink may further contain other components as needed, including a water-dispersible resin other than the block copolymer described above, a crosslinking agent, and other additives.

[0081] (Water dispersible resin) From the viewpoint of further improving the fixability of the pigment to fabric, it is preferable that the ink further contains a water-dispersible resin other than the above-mentioned block copolymer. Such a water-dispersible resin is contained in the ink as resin particles and can have the function of further improving the fixability of the pigment, etc. to fabric. The water-dispersible resin is preferably an anionic water-dispersible resin containing an anionic functional group. Examples of the anionic functional group include a hydroxyl group, a carboxyl group, and a sulfonic acid group.

[0082] Examples of anionic water-dispersible resins include anionic urethane resins, butadiene resins, (meth)acrylic resins, polystyrene resins, etc. Among these, anionic urethane resins and anionic (meth)acrylic resins are preferred. These resins bond with the anionic block copolymer through intermolecular hydrogen bonds, which makes it easier to improve adhesion to fabrics and abrasion resistance.

[0083] Examples of anionic (meth)acrylic resins include (meth)acrylic acid ester copolymers, styrene-(meth)acrylic copolymers, silicone-(meth)acrylic copolymers, and acrylic-modified fluororesins, each of which contains a structural unit derived from (meth)acrylic acid, styrene sulfonic acid, hydroxystyrene, or the like.

[0084] Examples of the anionic styrene-(meth)acrylic copolymer include styrene-(meth)acrylic acid copolymer and styrene-(meth)acrylic acid-(meth)acrylic acid ester copolymer, which contain structural units derived from (meth)acrylic acid, styrenesulfonic acid, hydroxystyrene, etc. 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, dicyclopentenyloxyethyl (meth)acrylate, etc.

[0085] Anionic urethane resins are polymers obtained by reacting polyol with polyisocyanate, and contain carboxyl groups, sulfonic acid groups, and the like in part or all of the polyol or polyisocyanate. 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), silicone polyols, etc., and 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, tetramethylxylylene diisocyanate, etc.

[0086] 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 anionic water-dispersible resin may be, for example, from −30° C. to 100° C., preferably from −10° C. to 50° C.

[0087] 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.

[0088] The average particle size of the water-dispersible resin is not particularly limited, but is preferably 300 nm or less, and more preferably 130 nm or less, from the viewpoint of preventing nozzle clogging of the inkjet head. The average particle size of the anionic water-dispersible resin can be measured by laser diffraction / scattering particle size distribution measurement.

[0089] The content of the water-dispersible resin is preferably 1% by mass or more and 15% by mass or less relative to the ink. When the content of the anionic water-dispersible resin is 1% by mass or more, the viscosity of the ink is easily increased appropriately, which not only improves the ejection stability but also 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 pigment ink does not become too high, making it less likely to cause nozzle clogging and the like. For the same reasons, the content of the anionic water-dispersible resin is more preferably 2% by mass or more and 10% by mass or less relative to the ink.

[0090] (Crosslinking agent) Furthermore, when the ink contains an anionic water-dispersible resin, or when a second treatment liquid is used, at least one of the ink and the second treatment liquid may further contain a crosslinking agent for crosslinking the anionic water-dispersible resin.

[0091] The crosslinking agent is preferably a compound having at least two functional groups in the molecule that react with the crosslinkable groups (hydroxyl groups, carboxyl groups, and ketone groups) of the anionic water-dispersible resin. Examples of crosslinking groups that react with hydroxyl groups include isocyanate groups and blocked isocyanate groups. Examples of crosslinking groups that react with carboxyl groups include oxazolyl groups, aziridine groups, and carbodiimide groups. Examples of crosslinking groups that react with ketone groups include hydrazide groups.

[0092] Specifically, examples of crosslinking agents that react with hydroxyl groups include Fixer N (a blocked isocyanate-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.). Examples of crosslinking agents that react with carboxyl groups include Fixer F (an aziridine-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.). Examples of crosslinking agents that react with ketone groups include adipic acid dihydrazide (ADH, a hydrazine-based crosslinking agent).

[0093] For example, adipic acid dihydrazide is most preferred as the crosslinking agent contained in the ink, and a water-dispersible resin containing a structural unit derived from diacetone acrylamide (DAAM) is preferred as the anionic water-dispersible resin having a crosslinkable group that reacts with adipic acid dihydrazide, because this allows for long-term storage at room temperature while also allowing for crosslinking at room temperature.

[0094] (Other additives) The ink may further contain additives other than those described above, if necessary. Examples of the additives include surfactants, preservatives, and antifungal agents.

[0095] 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.

[0096] 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.

[0097] 1-2. First treatment liquid 1-2-1. Cationic flocculants The cationic flocculant aggregates the pigment dispersion containing the anionic block copolymer contained in the ink. Aggregation by the cationic flocculant utilizes an electrical effect.

[0098] Cationic flocculants that cause aggregation by electrical action include compounds with cationic groups and polyvalent metal salts. These cationic flocculants can interact with the anionic block copolymer contained in the pigment dispersion in the ink.

[0099] 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.

[0100] Examples of cationic resins include cationic urethane resins, cationic olefin resins, and cationic alkylamine resins. Commercially available examples include MPT-60 (manufactured by Mitsubishi Pencil Co., Ltd.) and Unisense KHE. - 100L (manufactured by Senka Corporation), and MZ477 (urethane resin, manufactured by Takamatsu Oil & Fat Co., Ltd.). Among them, cationic alkylamine resins MPT-60 and Unisense KHE100L (manufactured by Senka Corporation) are preferred as cationic resins. This makes it easier to generate interactions with the anionic block copolymer.

[0101] Polyvalent metal salts can be water-soluble compounds having a divalent or higher polyvalent metal ion and an associated anion. Examples of polyvalent metal ions include Ca 2+ , Cu 2+ , Ni 2+ , Mg 2+ , Zn 2+ , Ba 2+ Divalent metal ions such as Al 3+ , Fe 3+ , Cr 3+ Examples of anions include trivalent metal ions such as Cl - , I - , Br - , SO4 2- , ClO 3- , NO 3- , and HCOO - , CH3COO - Examples of such polyvalent metal salts include zinc acetate dihydrate, magnesium nitrate, calcium chloride, magnesium chloride, aluminum chloride, magnesium sulfate, and metal salts of organic acids such as calcium salts, magnesium salts, nickel salts, and aluminum salts of acetic acid. Of these, calcium salts and magnesium salts are preferred, and calcium nitrate and calcium chloride are more preferred.

[0102] Among these, compounds having cationic groups are preferred, and cationic resins are more preferred. In particular, fabrics treated with a first treatment liquid containing a cationic resin are more effective at aggregating pigment dispersions than fabrics treated with a polyvalent metal salt or an organic acid. Therefore, the use of the anionic block copolymer described above is more likely to result in uneven density and color in the image. Even in such cases, in this embodiment, uneven density and color can be suppressed by using an ink containing the silicone acrylic resin described above.

[0103] The cationic resin preferably has a cation value of 0.5 mmol / g or more and 10.0 mmol / g or less, and more preferably 1.2 mmol / g or more and 6.2 mmol / g or less. When the cationic resin has a cation value of 0.5 mmol / g or more, the aggregation reaction proceeds more easily, and the abrasion fastness can be further improved. When the cationic resin has a cation value of 10.0 mmol / g or less, the aggregation reaction can be prevented from proceeding excessively.

[0104] The cation value of the cationic resin is a value measured by the following colloid titration method. (1) Prepare an aqueous dispersion of the resin. (2) Toluidine blue is added as an indicator. (3) Titrate using PVSK (potassium polyvinyl sulfate) solution as the titrant. The endpoint is when the color of the dispersion changes from blue to red. (4) The cation value is calculated from the amount of resin (solid content) in the aqueous dispersion and the titration amount of the PVSK solution.

[0105] The content of the cationic flocculant in the first treatment liquid is preferably 1.0% by mass or more and 20% by mass or less, and more preferably 2.0% by mass or more and 10% by mass or less. A content of 2.0% by mass or more can further promote aggregation of the pigment dispersion. Furthermore, a content of 10% by mass or less of the cationic flocculant can further prevent deterioration of texture.

[0106] 1-2-2. Water-based solvents The aqueous solvent preferably contains water and further contains a water-soluble organic solvent.

[0107] The content of water in the first treatment liquid is, for example, preferably 20% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, relative to the first treatment liquid.

[0108] The content of the water-soluble organic solvent in the first treatment liquid is, for example, preferably 20% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 60% by mass or less, relative to the first treatment liquid.

[0109] 1-2-3. Other ingredients The first treatment liquid may further contain other components in addition to those described above, as necessary. The other components may be the same as the other additives used in ink.

[0110] 1-3. Second processing liquid The second treatment liquid contains a water-dispersible resin and an aqueous solvent.

[0111] 1-3-1. Water-dispersible resin The water-dispersible resin may be the same as the silicone acrylic resin used in the ink or other water-dispersible resins, etc. Among them, from the viewpoint of preventing deterioration of the texture when combined with the ink, anionic water-dispersible resins are preferred, and water-dispersible resins with a Tg of 20°C are more preferred.

[0112] The content of the water-dispersible resin in the second treatment liquid is preferably 1.0% by mass or more and 20% by mass or less, and more preferably 3.0% by mass or more and 10% by mass or less. A content of 1.0% by mass or more can further improve the fixation of the pigment to the fabric and the abrasion resistance. Furthermore, a content of 20% by mass or less of the water-dispersible resin can further prevent deterioration of the texture.

[0113] 1-3-2. Water-based solvents The content of the water-soluble organic solvent in the second treatment liquid is, for example, preferably 10% by mass or more and 65% by mass or less, and more preferably 20% by mass or more and 45% by mass or less, relative to the second treatment liquid.

[0114] Similarly, the water content in the second treatment liquid is preferably, for example, 30% by mass or more and 85% by mass or less, and more preferably 50% by mass or more and 75% by mass or less, relative to the second treatment liquid.

[0115] 1-3-3. Other ingredients The second treatment liquid may further contain other components in addition to those described above, as necessary. The other components may be the same as the crosslinking agent and other additives used in ink.

[0116] The ink, first treatment liquid, and second treatment liquid described above may be provided as an inkjet printing ink set. For example, the inkjet printing ink set includes at least the first treatment liquid and the ink, and may further include the second treatment liquid.

[0117] Next, an image forming method using the ink and the like described above will be described.

[0118] 2. Image forming method An image forming method according to one embodiment of the present invention includes the steps of: 1) preparing a dry fabric having a cationic flocculant attached thereto (hereinafter also referred to as a treated fabric); and 2) applying an ink containing a pigment, an anionic block copolymer, a silicone acrylic resin, and water onto the fabric by an inkjet method.

[0119] 2-1. Process for preparing treated fabric In this step, a dry fabric having a cationic flocculant attached thereto is prepared. The fabric may be one that has been dried after applying the first treatment liquid containing a cationic flocculant to the fabric. Treated fabrics that have undergone these treatments may be obtained from elsewhere, or may be treated in this step to prepare treated fabrics. Specifically, the dry fabric is one in which the content of the solvent (specifically, the aqueous solvent derived from the treatment liquid) in the treated fabric is preferably 5.0 g / m. 2 Less than 3.0 g / m, more preferably 3.0 g / m 2 The solvent content is measured by the change in weight before and after drying the treated fabric at 150°C for 3 minutes.

[0120] In this embodiment, a treated fabric can be prepared through a process of applying the first treatment liquid to the fabric and a process of drying the fabric to which the first treatment liquid has been applied. Each process will be described below.

[0121] 2-1-1. Step of applying first treatment liquid The first treatment liquid is applied to the fabric to cause the cationic flocculant to adhere to the fabric. As described above, the cationic flocculant facilitates aggregation of the pigment dispersion containing the anionic block copolymer contained in the ink.

[0122] Examples of fiber types for fabrics include natural fibers such as cotton, linen, wool, and silk, and chemical fibers such as rayon, vinylon, nylon, acrylic, polyurethane, polyester, and acetate. The fabric may be made from these fibers in any form, such as woven fabric, nonwoven fabric, or knitted fabric. The fabric may also be a blended woven fabric or blended nonwoven fabric of two or more types of fibers.

[0123] The method for applying the first treatment liquid to the fabric 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 performing the method together with the ink application step described below.

[0124] The amount of the first 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, it is preferable to apply the first treatment liquid so that the mass ratio (P / Q) of the amount of flocculant applied to the fabric, P, to the amount of anionic block copolymer that can function as a pigment dispersant, Q, is 1 / 1 or more and 10 / 1 or less. This makes it easier to aggregate the pigment dispersion. Specifically, the amount of flocculant applied, for example, in the case of a cationic resin, is 0.1 g / m 2 of the treated fabric. 2 More than 1.5g / m 2 It can be as follows:

[0125] 2-1-2. Drying process Next, the fabric to which the first treatment liquid has been applied is dried.

[0126] In this embodiment, the fabric is dried until the amount of aqueous solvent remaining on the fabric derived from the first treatment liquid is preferably 20% by mass or less, more preferably 5% by mass or less, relative to the total amount of aqueous solvent derived from the treatment liquid applied to the fabric. The amount of aqueous solvent remaining on the fabric can be calculated from the weight of the fabric before and after application of the first treatment liquid and the composition of the first treatment liquid (the content ratio of aqueous solvent).

[0127] 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 heating 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 is a temperature at which the aqueous solvent in the first treatment liquid can be removed, and may be, for example, 80°C or higher and 180°C or lower.

[0128] 2-2. Ink application process Next, the ink described above is applied by an inkjet method onto the fabric to which the prepared cationic flocculant has been attached.

[0129] The amount of ink applied is not particularly limited, but may be, for example, 5 g / m 2 More than 30g / m2 The following (including solvents) can be used:

[0130] 2-3. Other processes The image forming method according to the present embodiment may further include other steps as necessary. For example, a step of applying a second treatment liquid may be further carried out simultaneously with or after the step of applying the ink described above.

[0131] In the step of applying the second treatment liquid, the second treatment liquid is further applied onto the ink applied to the fabric, thereby further improving the fixation of the pigment to the fabric and the abrasion resistance.

[0132] The method for applying the second treatment liquid is not particularly limited, and may be any of a dipping method, a spray method, and an inkjet method, but is preferably an inkjet method.

[0133] The amount of the second treatment liquid to be applied is not particularly limited, but is, for example, 5.0 g / m 2 More than 20.0g / m 2 The following (including solvents) can be used:

[0134] Next, the ink and second treatment liquid applied to the fabric may be further dried. The drying method is not particularly limited, and may be performed at room temperature or by heating. The heating method may be a method using a heater, a hot air dryer, a heating roller, or the like, and is preferably a method in which the fabric is heated from both sides using a hot air dryer and a heater.

[0135] The drying temperature is not particularly limited as long as it is a temperature at which the water-soluble organic solvent and water in the ink can be removed, and can be, for example, from 80° C. to 180° C. The drying time depends on the drying temperature, but can be, for example, from 1 minute to 10 minutes.

[0136] 2-4. Effect As described above, this embodiment involves the steps of applying a first treatment liquid to a fabric, drying the applied first treatment liquid, and applying ink to the dried fabric. In this image-forming method, in which fabric treatment with a first treatment liquid is performed offline, an ink containing an anionic block copolymer and a silicone acrylic resin is used. This allows ink droplets to sufficiently wet and spread on the fabric, even when the fabric is dry and has a cationic flocculant attached, while the pigment dispersion quickly aggregates on the fabric. This allows for the formation of images with high friction resistance and reduced density and color unevenness. [Example]

[0137] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0138] 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.

[0139] 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.

[0140] 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.

[0141] 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.

[0142] <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.

[0143] 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.

[0144] <Preparation of Pigment Dispersion A-2> Pigment Dispersion A-2 was prepared in the same manner as Pigment Dispersion A-1, except that the block copolymer P-1 was changed to random copolymer P-2 as the pigment dispersant.

[0145] 1-3. Silicone acrylic resin D-1: Silicone acrylic resin (weight average molecular weight 30,000, polydimethylsiloxane (PDMS): polymethyl acrylate (PMA) = 90:10 (mass ratio), nonionic, Tg 100°C) D-2: Silicone acrylic resin (weight average molecular weight 30,000, PDMS:PMA = 60:40 (mass ratio), nonionic, Tg: 120°C) D-3: Silicone acrylic resin (weight average molecular weight 30,000, PDMS:PMA = 99.5:0.5 (mass ratio), nonionic, Tg: 0°C) D-4: Silicone acrylic resin (weight average molecular weight 100,000, PDMS:PMA = 90:10 (mass ratio), nonionic, Tg: 140°C) D-5: Silicone acrylic resin (weight average molecular weight 1000, PDMS:PMA = 90:10 (mass ratio), nonionic, Tg: 0°C)

[0146] Silicone acrylic resin D-3 was prepared in the following manner. (Silicone Acrylic D-3) i) Preparation of an emulsion composition containing organopolysiloxane Solution 1 was prepared by dissolving 555 g of hexamethylcyclotrisiloxane, 0.6 g of KBM-502 (γ-methacryloxypropylmethyldimethoxysilane), 44 g of KBM-13 (methyltrimethoxysilane), and 6 g of sodium lauryl sulfate in 54 g of ion-exchanged water. Additionally, solution 2 was prepared by dissolving 6 g of dodecylbenzenesulfonic acid in 54 g of pure water. These solutions were combined and homogeneously emulsified in a homomixer, after which 430 g of ion-exchanged water was gradually added to dilute the mixture. The mixture was then heated under a pressure of 300 kgf / cm. 2The mixture was passed through a high-pressure homogenizer twice at 100°C, yielding a uniform white emulsion. This emulsion was transferred to a 2 L glass flask equipped with a stirrer, thermometer, and reflux condenser, and subjected to polymerization at 60-70°C for 24 hours. After that, the mixture was neutralized with 12 g of a 10% aqueous sodium carbonate solution to a pH of 6-8, yielding a silicone emulsion composition. The non-volatile content of this silicone emulsion composition was 44.5%.

[0147] ii) Production of Silicone Acrylic D-3 (Silicone Acrylic Graft Copolymer Resin) To the silicone emulsion composition obtained above, 3 g of methyl methacrylate (MMA) was added dropwise over 10 minutes. At 30°C, peroxide and a reducing agent were added to carry out an oxidation-reduction reaction, resulting in acrylic graft copolymerization. This resulted in an emulsion composition containing a silicone acrylic graft copolymer resin. The nonvolatile content of the emulsion composition was 44.8%. The mass ratio of the organosiloxane structural unit content per mole of silicone acrylic graft copolymer resin, taken as the numerator and the mass of the structural unit content derived from the (meth)acrylic acid derivative as the denominator, i.e., the ratio of organosiloxane structure to acrylic acid structure, was 99.5 / 0.5.

[0148] The other silicone acrylic resins D-1, D-2, D-4, and D-5 were prepared in the same manner, except that the amounts of raw material monomers and reaction times were changed so that the copolymerization ratios and weight average molecular weights of the resulting silicone acrylic resins would be as described above.

[0149] 1-4. Anionic water-dispersible resin E-1: Urethane resin (Superflex 300 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Tg: -42°C) E-2: Acrylic resin (Movinyl 6751D, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Tg: -32°C) The Tg is a value measured by differential scanning calorimetry in accordance with JIS K 7121 under the measurement conditions of a temperature rise rate of 10°C / min.

[0150] 1-5. Crosslinking agent Fixer N (blocked isocyanate crosslinking agent) manufactured by Matsui Pigment Chemical Industry Co., Ltd.

[0151] 1-6. Preparation of ink <Preparation of 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 Silicone acrylic resin D-1: 0.5 parts by mass Urethane resin E-1 (anionic water-dispersible resin): 10.0 parts by mass Glycerin (solvent): 10 parts by mass Ethylene glycol (EG) (solvent): 20 parts by mass Proxel GXL(S) (preservative): 0.1 parts by weight Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 0.1 parts by mass Ion exchange water: remaining amount

[0152] <Preparation of Inks 1-2 to 1-13> Inks 1-2 to 1-13 were obtained in the same manner as Ink 1-1, except that the types and contents of the pigment dispersant, silicone acrylic resin, and binder resin were changed as shown in Table 1 and the amount of ion-exchanged water was adjusted so that the total amount was 100 parts by mass.

[0153] <Preparation of Ink 1-14> Ink 1-14 was obtained in the same manner as Ink 1-1, except that 0.5 parts by mass of the silicone acrylic resin was replaced with 0.5 parts by mass of a silicone surfactant (TEGOWET250 manufactured by Evonik), and the amount of ion-exchanged water was adjusted so that the total amount was 100 parts by mass.

[0154] Table 1 shows the compositions of the main components of the resulting inks 1-1 to 1-14.

[0155] [Table 1]

[0156] 2. Preparation of Treatment Solutions 2-1. First treatment liquid <Preparation of first treatment liquid 2-1> The following components were mixed to a total amount of 100 parts by mass to prepare a first treatment liquid 2-1. Unisense KHE-100L (flocculant) (manufactured by Senka Corporation, cationic resin, cation value 4.4 mmol / g): 3.0 parts by mass Glycerin (solvent): 10.0 parts by mass Ethylene glycol (solvent): 30.0 parts by mass Proxel GXL(S) (preservative): 0.1 parts by weight Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 0.1 parts by mass Ion exchange water: remaining amount

[0157] <Preparation of first treatment liquid 2-2> First treatment liquid 2-2 was obtained in the same manner as first treatment liquid 2-1, except that the cationic value of the flocculant was changed to MPT-60 (manufactured by Mitsubishi Pencil Co., Ltd., cationic resin, cationic value 5.5 mmol / g), which has a higher cationic value than the flocculant used in first treatment liquid 2-1.

[0158] The cation value of the cationic resin was a value measured by the following colloid titration method. (1) Prepare an aqueous dispersion of the resin. (2) Toluidine blue is added as an indicator. (3) Titrate using PVSK (potassium polyvinyl sulfate) solution as the titrant. The endpoint is when the color of the dispersion changes from blue to red. (4) The cation value is calculated from the amount of resin (solid content) in the aqueous dispersion and the titration amount of the PVSK solution.

[0159] 2-2. Second processing liquid <Preparation of second treatment liquid 3-1> The following components were mixed to a total amount of 100 parts by mass to prepare a second treatment liquid 3-1. Urethane resin E-1 (anionic water-dispersible resin): 10.0 parts by mass Glycerin (solvent): 10.0 parts by mass Ethylene glycol (solvent): 30.0 parts by mass Proxel GXL(S) (preservative): 0.1 parts by weight Olfine E1010 (manufactured by Nissin Chemical Industry Co., Ltd., surfactant): 0.1 parts by mass Ion exchange water: remaining amount

[0160] 4. Imaging and Evaluation [Test 1] (Process for preparing treated fabric) As the fabric, cotton broadcloth 40 (100% cotton) was prepared. This fabric was immersed in a bath filled with the first treatment liquid 2-1, and then excess first treatment liquid was squeezed out with a mangle roll to leave a coating amount of the first treatment liquid of 30 g / m 2 It was given so that Next, the fabric to which the first treatment liquid had been applied was dried at 130°C for 10 minutes to obtain a treated fabric. The amount of the aqueous solvent remaining in the treated fabric was about 5.0% by mass of the applied aqueous solvent (the amount of the aqueous solvent in the treated fabric was 3.0 g / m 2 ) was.

[0161] (Step of applying ink) The ink 1-1 and the second treatment liquid 3-1 were set in a simple printing tester equipped with a KM1024i head as an inkjet head. Then, the prepared ink was applied to the surface of the pretreated fabric in an amount of 20 g / m using a simple printing tester. 2 It was given so that Next, the second treatment liquid 3-1 was applied at a rate of 15 g / m 2 It was given so that The ink and second treatment liquid application process was repeated so that the applied ink and second treatment liquid overlapped each other, and the ink and second treatment liquid were applied eight times each to form an image. All of these applications were performed using an inkjet and multi-pass method at a main scanning speed of 540 dpi and a sub-scanning speed of 720 dpi. "dpi" refers to the number of ink droplets (dots) per 2.54 cm. The ejection frequency was 22.4 kHz. The image formed included a fine line grid, gradation, and solid areas (total size 200 mm x 200 mm).

[0162] (Drying and fixing process) Thereafter, the fabric on which the image was formed was dried in a belt conveying dryer at 130° C. for 10 minutes, thereby obtaining an image-formed product.

[0163] [Tests 2-17] Image formation was carried out in the same manner as in Test 1, except that at least one of the type of ink and the type of second treatment liquid was changed as shown in Table 2.

[0164] 5. Evaluation The resulting image-formed product was evaluated as follows.

[0165] (1) Injection stability The prepared ink was ejected using a fixed Konica Minolta KM1024iMHE printer at 25°C and 50% RH using a line method with a droplet volume of 13 pL. After confirming that the filled ink was being ejected from all 60 nozzles at the start of ejection, the ink was allowed to eject continuously for 60 minutes. After the 60 minutes of continuous ejection had finished, the number of nozzles that had been able to eject to the end (the number of nozzles ejecting after the 60 minutes of continuous ejection had finished) was counted. Then, the ejection stability was evaluated based on the following evaluation criteria. 〇: Number of nozzles discharged after 60 minutes of continuous discharge is 60 △: Number of nozzles ejected after 60 minutes of continuous ejection is 55 or more but less than 60 ×: The number of nozzles ejecting after 60 minutes of continuous ejection is less than 55 △ or higher was considered to be within the acceptable range.

[0166] (2) Abrasion resistance A 100mm x 100mm area of ​​the formed image was rubbed with a white cotton cloth by rubbing it back and forth 100 times under a load of 200g. The white cotton cloth used for rubbing was a white cotton cloth that had been wetted with water to a moisture content of approximately 100%. After rubbing, color transfer to the white cotton cloth was observed, and the wet rubbing fastness was evaluated according to the following criteria. ◎: Almost no color transfer 〇: Slight color transfer, but good condition △: Color transfer occurs, but within acceptable limits ×: Color transfer occurs and exceeds the acceptable range △ or higher was considered to be within the acceptable range.

[0167] (3) Uneven density and color The solid quality of the entire solid image formed was visually observed and evaluated according to the following criteria. ◯: The ink has excellent wettability, and the image is uniform with no uneven density and no ink voids are observed. △: The ink wettability is good, and although there are areas where the density varies, no ink loss is observed, making the image practically acceptable. ×: Image in which the ink wettability is slightly insufficient, there are areas where the ink has fallen out, and there are slight white spots ××: Image where the ink is not wet enough, there are areas where the ink has fallen out, and there are noticeable white areas. △ or higher was considered to be within the acceptable range.

[0168] (4) Texture The texture of the image-formed product and the fabric was evaluated sensorily by touching with the fingers, based on the following criteria. ○: The original softness of the fabric is maintained, and it is almost the same as before image formation. △: It is slightly harder than before image formation, but the texture of the fabric is not impaired and there is no problem in practical use. ×: The fabric is harder than before image formation, the texture of the fabric is damaged, and it is at a level that is problematic for practical use. △ or higher was considered to be within the acceptable range.

[0169] The evaluation results of tests 1 to 17 are shown in Table 2.

[0170] [Table 2]

[0171] As shown in Table 2, when ink containing a random copolymer was applied to dry pretreated fabric, it was found that the rub fastness was low (Test 10). On the other hand, when ink containing a block copolymer but no silicone acrylic resin was applied to dry pretreated fabric, it was found that although rub fastness was improved to some extent, density unevenness and color unevenness occurred (Test 11).

[0172] In contrast, when an ink containing a block copolymer and a silicone acrylic resin is applied to a dry pretreated fabric, it is found that uneven density and color can be suppressed while improving friction resistance (Tests 1 to 9, 12 to 14).

[0173] In particular, it can be seen that the higher the content of the structural unit derived from PDMS in the silicone acrylic resin, 80% by mass or more, the more improved the abrasion resistance becomes (comparison of Tests 1, 4, and 5).

[0174] It is also clear that the higher the weight average molecular weight of the silicone acrylic resin, 30,000 or more, the more the density and color unevenness can be suppressed and the more the abrasion resistance is improved (comparison of Tests 1, 6 and 7).

[0175] Furthermore, it can be seen that by using E-1 containing an acrylic resin as the second treatment liquid, unevenness in density and color can be further suppressed and the abrasion resistance is further improved (comparison of Tests 2 and 3).

[0176] Furthermore, when treatment liquid 2-2 containing a coagulant with a high cationic value was used, uneven density and color occurred more significantly (Test 17), but it was found that uneven density and color could be effectively suppressed by using ink 1-1 (Test 11).

[0177] It can also be seen that even when a silicone surfactant is used instead of a silicone acrylic resin, the injection stability and the friction resistance also decrease (comparison of Tests 1 and 16). [Industrial Applicability]

[0178] According to the present invention, it is possible to provide an image forming method that can form an image with high abrasion resistance on fabric while suppressing uneven density and color even on fabric that has been processed offline.

Claims

1. An image forming method, comprising: Providing a dry fabric having a cationic flocculant attached thereto; applying an ink containing a pigment, an anionic block copolymer, a silicone acrylic resin, and an aqueous solvent onto the fabric by an inkjet method; Including, The anionic block copolymer contains a hydrophilic block A and a hydrophobic block B. Image forming method.

2. The step of preparing the fabric includes: applying a treatment liquid containing a cationic flocculant and an aqueous solvent to the fabric; drying the fabric to which the treatment liquid has been applied; Including, The image forming method according to claim 1 .

3. In the drying step, drying the fabric until the remaining amount of the aqueous solvent in the fabric is 20 mass % or less of the total amount of the aqueous solvent applied to the fabric; The image forming method according to claim 2 .

4. The anionic block copolymer contains two hydrophilic blocks A arranged at both ends of the molecule and a hydrophobic block B arranged between the two hydrophilic blocks A. The image forming method according to claim 1 .

5. The silicone acrylic resin contains a structural unit X derived from a polyorganosiloxane having a radical polymerizable group and a structural unit Y derived from a (meth)acrylic acid ester, the content of the structural unit X is 80% by mass or more and 99% by mass or less based on the total amount of the structural unit X and the structural unit Y; The image forming method according to claim 1 .

6. The weight average molecular weight of the silicone acrylic resin is 1,000 or more and 500,000 or less. The image forming method according to claim 1 .

7. the content of the silicone acrylic resin in the ink is 0.2% by mass or more and 10% by mass or less with respect to the ink; The image forming method according to claim 1 .

8. the ink further contains a water-dispersible resin different from the anionic block copolymer; The image forming method according to claim 1 .

9. The method further comprises a step of applying a second treatment liquid containing a water-dispersible resin and an aqueous solvent onto the fabric to which the ink has been applied. The image forming method according to claim 1 .

10. The anionic water-dispersible resin includes a (meth)acrylic resin or a urethane resin. The image forming method according to claim 8 or 9.

11. At least one of the ink and the second treatment liquid further contains a crosslinking agent. The image forming method according to claim 9.

12. The flocculant contains a polyvalent metal salt or a compound having a cationic group. The image forming method according to claim 1 .

13. The compound having a cationic group includes a cationic resin. The image forming method according to claim 12.

Images