Image forming method and ink set

Abstract

To provide a method for forming an image capable of maintaining high friction fastness over a long term, without damaging texture of a fabric.SOLUTION: The image formation method of the present invention comprises: applying an ink containing a pigment and resin particles on a fabric by an inkjet method; and applying a post treatment liquid containing a lubricant on the ink applied on the fabric by wet on wet. When the solubility parameter of the resin constituting the resin particles is SP1(cal / cm3)1 / 2, and the solubility parameter of the lubricant is SP2(cal / cm3)1 / 2, 0.3≤SP1-SP2≤0.8 is satisfied.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to an image forming method and an ink set. [Background technology]

[0002] Traditionally, the known method of textile printing involved immersing the fabric in a dye bath, but this method was inefficient due to the long dyeing time. In recent years, however, inkjet printing, which allows for dyeing in a short time and offers high production efficiency, has become widely used.

[0003] In inkjet printing, tiny droplets of ink are ejected from an inkjet recording head and deposited onto fabric to form an image. While dye-based inks are the mainstream for inkjet printing, the use of pigment-based inks, which eliminate the need for post-processing steps such as washing away undissolved or unreacted dyes, is being considered.

[0004] Pigment inks exhibit high color development by retaining pigment particles on the surface of fabrics, but tend to have lower pigment particle fixation and inferior friction fastness compared to dye inks. Therefore, research is being conducted to improve pigment particle fixation and friction fastness by adding binder resin (resin particles) to the ink or by applying a post-treatment solution to the ink.

[0005] For example, Patent Document 1 discloses an inkjet printing method that includes the steps of inkjet coating an ink composition onto a fabric containing a first treatment agent containing a cationic substance, and coating the fabric with a second treatment agent containing resin particles and a lubricant. In the examples, an ink composition containing a pigment and a urethane resin, and a second treatment agent containing an acrylic resin and a silicone-based wax are disclosed.

[0006] Patent Document 2 discloses an inkjet printing method that includes the steps of: applying a processing solution containing a polyvalent metal salt to a fabric to obtain a processed fabric; applying a white ink composition to the processed fabric using an inkjet method to obtain a printed fabric; and drying the printed fabric. It is also disclosed that the white ink composition includes a resin having a silicone group as a first fixing resin, and a urethane resin, polyester resin, or acrylic resin as a second fixing resin.

[0007] Patent Document 3 discloses an ink set comprising a color ink containing a colorant and an overcoat liquid containing a polyester resin and a lubricant, but without a colorant. In the examples, it is disclosed that inkjet printing is performed using an ink containing a urethane resin or polyester resin and an overcoat liquid containing a urethane resin or polyester resin and polyethylene wax. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2021-85128 [Patent Document 2] Japanese Patent Publication No. 2021-98796 [Patent Document 3] Japanese Patent Publication No. 2013-221141 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In the above-mentioned Patent Document 1, ink is applied to a fabric by inkjet, then dried, and a post-treatment solution is applied (wet-on-dry coating). However, in the resulting image-forming product, an interface easily forms between the ink layer and the post-treatment layer, and the post-treatment layer tends to peel off due to friction. Therefore, it was difficult to maintain friction fastness over a long period of time.

[0010] On the other hand, in Patent Document 3, it is stated that ink application by inkjet and overcoat liquid application may be performed simultaneously (wet-on-wet coating). In this case, an interface is less likely to be formed between the ink layer and the overcoat layer, and the overcoat layer is less likely to peel off due to friction. However, since the affinity between the resin particles contained in the ink and the lubricant contained in the overcoat liquid is low, the lubricant easily diffuses on the fabric surface in a short time, and it has been difficult to maintain the friction fastness over a long period of time.

[0011] In Patent Document 2 above, ink containing two types of resin particles is applied onto the fabric, but no post-treatment liquid is applied. Therefore, immediately after applying the ink onto the fabric, the resin particles easily penetrate into the fabric, and the texture of the fabric is easily impaired.

[0012] The present invention has been made in view of the above circumstances, and an object thereof is to provide an image forming method and an ink set capable of maintaining high friction fastness over a long period of time without impairing the texture of the fabric.

Means for Solving the Problems

[0013] The image forming method of the present invention includes a step of applying, by an inkjet method, ink containing a pigment and resin particles onto a fabric, and a step of wet-on-wet applying a post-treatment liquid containing a lubricant onto the ink applied to the fabric, and when the solubility parameter of the resin constituting the resin particles is SP1 (cal / cm 3 ) 1 / 2 and the solubility parameter of the lubricant is SP2 (cal / cm 3 ) 1 / 2 it satisfies 0.3 ≦ SP1 - SP2 ≦ 0.8.

[0014] The ink set of the present invention is an ink set for inkjet printing, and includes ink containing a pigment and resin particles, and a post-treatment liquid containing a lubricant, and when the solubility parameter of the resin constituting the resin particles is SP1 (cal / cm 3 ) 1 / 2 and the solubility parameter of the lubricant is SP2 (cal / cm 3 )1 / 2 When it is set as such, 0.3 ≤ SP1 - SP2 ≤ 0.8 is satisfied.

Advantages of the Invention

[0015] According to the present invention, it is possible to provide an image forming method capable of maintaining high rubbing fastness over a long period without impairing the texture of the fabric.

Embodiments for Carrying Out the Invention

[0016] As a result of intensive studies on the above problems, the present inventors have found that 1) applying the post-treatment liquid in a wet-on-wet manner and 2) moderately increasing the affinity between the resin particles contained in the ink and the lubricant contained in the post-treatment liquid can maintain the rubbing fastness over a long period without impairing the texture of the fabric.

[0017] Regarding (1) Applying the post-treatment liquid in a wet-on-wet manner means applying the post-treatment liquid before most of the droplets of the previously applied ink have completely dried. Specifically, in terms of the unit area of the recording region, (the remaining amount of ink at the time of applying the post-treatment liquid) / (the amount of ink adhered) is 0.40 to 1.0, preferably 0.50 to 1.0, more preferably 0.70 to 1.0, and even more preferably 0.80 to 1.0. Here, the "remaining amount of ink at the time of applying the post-treatment liquid" refers to the amount of liquid ink that remains without drying. The remaining amount can be adjusted by appropriately adjusting various conditions such as the time from applying the ink to applying the post-treatment liquid.

[0018] By applying the post-treatment liquid in a wet-on-wet manner, it becomes difficult to form an interface between the ink and the post-treatment liquid, and the compositional change in the thickness direction can be made continuous. Thereby, it is possible to suppress the peeling off of the post-treatment layer layer by layer due to friction. Thereby, since the effect of the lubricity by the lubricant can be sustained, the friction fastness can be maintained over a long period. Further, by applying the post-treatment liquid in a wet-on-wet manner, the ink and the post-treatment liquid are miscible, and the liquid components such as water and solvent that easily penetrate into the fabric relatively increase, so that the penetration of the resin particles between the fibers decreases and it becomes easier to stay on the fiber surface. Thereby, the fabric is less likely to become hard and the texture can be maintained well.

[0019] Regarding (2) Also, when the solubility parameter of the resin constituting the resin particles contained in the ink is SP1 (cal / cm 3 ) 1 / 2 and the solubility parameter of the lubricant contained in the post-treatment liquid is SP2 (cal / cm 3 ) 1 / 2 the resin particles and the lubricant are selected so as to satisfy 0.3 ≤ SP1 - SP2 ≤ 0.8.

[0020] As described above, when the post-treatment liquid is applied in a wet-on-wet manner, the post-treatment liquid is miscible with the ink. Here, if the difference SP1 - SP2 (hereinafter, also referred to as "ΔSP") between the solubility parameter of the resin particles contained in the ink and the solubility parameter of the lubricant contained in the post-treatment liquid is too large, the affinity between the resin particles and the lubricant is low, so the lubricant easily diffuses instantaneously to the surface of the continuous layer formed by the ink and the post-treatment liquid (the diffusion rate is high). As a result, when the surface of the continuous layer is worn, the lubricant is easily lost early and it is difficult to sustain the friction fastness. On the other hand, if ΔSP is too small, the affinity between the resin particles and the lubricant is too high (the diffusion rate of the lubricant is too low), so the lubricant is difficult to diffuse to the surface of the continuous layer. As a result, even when the surface of the continuous layer is worn, the lubricant is difficult to be exposed on the surface and it is difficult to sustain the friction fastness. In contrast, in the present invention, by adjusting ΔSP to the above range, that is, by making it appropriately small, the diffusion rate of the lubricant to the surface of the continuous layer, i.e., the deposition rate over time, can be adjusted. As a result, frictional robustness can be maintained over a long period of time. From a similar viewpoint, it is more preferable that ΔSP be 0.4 to 0.7.

[0021] Furthermore, if the resin particles are composite particles such as core-shell particles having a core layer and a shell layer, the dissolution parameter SP1 refers to the dissolution parameter of the resin component with the highest weight ratio from the perspective of continuous resin distribution in the coating film. Also, if two or more types of resin particles are included, it refers to the dissolution parameter of the resin particle with the highest weight ratio.

[0022] Furthermore, the post-treatment solution may also contain resin particles. However, the difference between the solubility parameter of the resin particles in the post-treatment solution and the solubility parameter of the lubricant should be between 0.3 and 2.0. This is because, from the viewpoint of improving short-term dry friction resistance, it is desirable for the lubricant in the post-treatment layer to diffuse quickly onto the surface.

[0023] The solubility parameter is also called the dissolution parameter. In this invention, the dissolution parameter SP1 of the resin particles is determined by measuring the degree of swelling with a known liquid and using the dissolution parameter at the highest degree of swelling. Specifically, the SP value is determined by measuring the degree of swelling of the resin particles in a known solvent using the following procedure. 1) Measure the degree of swelling when immersed in solvents with known solubility parameters (five types: hexane, toluene, ethyl acetate, acetone, and methanol). For the measurement of the degree of swelling, let W1 be the weight of the dry resin particles, and W2 be the weight after immersion in each solvent at 100% concentration at room temperature for 60 minutes. Then, calculate the degree of swelling using the following formula. Swelling degree (%) = (W2 - W1) / W1 × 100 2) Next, create a graph with the SP value of the solvent on the X-axis and the degree of swelling on the Y-axis, and draw an approximation curve. The approximation curve is determined by Gaussian approximation (normal distribution approximation). The SP value of the solvent is taken from "Fundamentals and Engineering of Coatings" by Yuji Harasaki, p. 53, Japan Processing Technology Association, 2010. 3) The value of the X axis at the peak of the approximation curve obtained in 2) above (i.e., the SP value at which the degree of swelling is maximum) is taken as the SP value of the resin particle. If the resin particles are, for example, core-shell type particles, then resin particles of a homopolymer of the monomer with the highest weight ratio among the monomer composition of the polymer constituting the core layer can be prepared, and their SP value can be determined using the method described above.

[0024] The solubility parameter SP2 of the lubricant can also be measured using the same method as described above. However, the type and number of solvents used to measure the swelling degree of the lubricant shall be the same as the type and number of solvents used to measure the swelling degree of the resin particles.

[0025] First, we will explain the composition of the ink and post-processing solution, and then we will explain the image formation method using them.

[0026] 1. Ink The ink according to this embodiment comprises a pigment and resin particles.

[0027] 1-1. Pigments The pigments contained in the ink are not particularly limited, but are preferably organic or inorganic pigments of the following numbers listed in the color index.

[0028] Examples of orange or yellow pigments include CI Pigment Orange 31, CI Pigment Orange 43, CI Pigment Yellow 12, CI Pigment Yellow 13, CI Pigment Yellow 14, CI Pigment Yellow 15, CI Pigment Yellow 17, CI Pigment Yellow 74, CI Pigment Yellow 83, CI Pigment Yellow 93, CI Pigment Yellow 94, CI Pigment Yellow 128, CI Pigment Yellow 138, CI Pigment Yellow 151, CI Pigment Yellow 154, CI Pigment Yellow 155, CI Pigment Yellow 180, CI Pigment Yellow 185, CI Pigment Yellow 213, and the like.

[0029] 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, 36.

[0030] 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, and 60.

[0031] Examples of green pigments include Pigment Green 7, 26, 36, and 50. 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.

[0032] Examples of black pigments include Pigment Black 7, 28, and 26.

[0033] Examples of commercially available pigments include Chromofine Yellow 2080, 5900, 5930, AF-1300, 2700L, Chromofine Orange 3700L, 6730, Chromofine Scarlet 6750, Chromofine Magenta 6880, 6886, 6891N, 6790, 6887, Chromofine Violet RE, Chromofine Red 6820, 6830, Chromofine 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. Chromofine Green 2GN, 2GO, 2G-550D, 5310, 5370, 6830, Chromofine 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 Kogyo); 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);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), Toner Magenta E02, Permanent Rubin F6B, Toner Yellow HG, Permanent Yellow GG-02, Hostapean Blue B2G (manufactured by Hoechst Industries); Novoperm P-HG, Hostapean Pink E, Hostapean Blue B2G (Clarant); includes 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 (Mitsubishi Chemical).

[0034] From the viewpoint of improving dispersibility in the ink, it is preferable that the pigment is further dispersed with a pigment dispersant. Pigment dispersants will be described later.

[0035] Furthermore, the pigment may be a self-dispersing pigment. A self-dispersing pigment has a surface modified with a hydrophilic group, and comprises pigment particles and a hydrophilic group bonded to its surface. Examples of hydrophilic groups include carboxyl groups, sulfonic acid groups, and phosphorus-containing groups. Examples of phosphorus-containing groups include phosphate groups, phosphonic acid groups, phosphinic acid groups, phosphite groups, and phosphate groups.

[0036] Examples of commercially available self-dispersing pigments include Cabot's Cab-O-Jet® 200K, 250C, 260M, and 270V (sulfonic acid group-containing self-dispersing pigments), Cab-O-Jet® 300K (carboxylic acid group-containing self-dispersing pigment), and Cab-O-Jet® 400K, 450C, 465M, 470V, and 480V (phosphate group-containing self-dispersing pigments).

[0037] The pigment content is not particularly limited, but from the viewpoint of easily adjusting the ink viscosity to the range described later and forming a higher density image, it is preferable that the pigment content be between 0.3% and 12% by mass relative to the ink. If the pigment content is 0.3% by mass or more, the resulting image tends to have vivid colors, and if it is 5% by mass or less, the ink viscosity does not become too high, so the injection stability is less likely to be impaired. From a similar viewpoint, it is more preferable that the pigment content be between 0.5% and 8% by mass relative to the ink.

[0038] 1-2. Resin particles Resin particles may have the function of fixing pigments and other substances to fabric. Examples of resins that make up the resin particles include (meth)acrylic resins, polystyrene resins, polyurethane resins, polyester resins, and polyalkylene resins. Among these, resins with a moderately low Tg are preferred from the viewpoint of not impairing the texture of the fabric. The Tg of the resin that makes up the resin particles is preferably 20°C or lower, and more preferably -55 to -5°C. The Tg of the resin can be determined in accordance with JIS K7121.

[0039] In particular, (meth)acrylic resins are preferred because they allow for a moderately low Tg of the resin and offer good frictional resistance. Specifically, it is preferable that the resin particles contain (meth)acrylic resin.

[0040] ((meth)acrylic resin) (Meth)acrylic resins are resins polymerized using monomers having (meth)acryloyl groups as the main component.

[0041] Monomers having a (meth)acryloyl group include: (meth)acrylic acid; (meth)acrylate esters ((meth)acrylate methyl, (meth)acrylate ethyl, (meth)acrylate propyl, (meth)acrylate n-butyl, (meth)acrylate isopropyl, (meth)acrylate isobutyl, (meth)acrylate 2-ethylhexyl, (meth)acrylate 2-hydroxypropyl, (meth)acrylate n-hexyl, (meth)acrylate n-dodecyl, (meth)acrylate n-stearyl, etc., (meth)acrylate phenylethoxy, (meth)acrylate cyclohexyl, (meth)acrylate hydroxyethyl, (meth)acrylate hydroxypropyl, (meth)acrylate benzyl, quaternary ammonium group-containing (meth)acrylate, glycidyl, (meth)acrylate, etc. containing functional groups (meth)acrylate, etc.); (Meth)acrylamides (e.g., (meth)acrylamide, (meth)methylacrylamide, (meth)ethylacrylamide, (meth)n-propylacrylamide, N-isopropyl(meth)acrylacrylamide, (meth)butylacrylamide, (meth)cyclohexylacrylamide, (meth)benzylacrylamide, hydroxymethylacrylamide, (meth)methoxymethylacrylamide, butoxymethylacrylamide, methoxyethylacrylamide, (meth)phenylacrylamide, diacetoneacrylamide, etc.) (meth)acrylonitrile, etc. These are some examples.

[0042] Monofunctional monomers that may be copolymerized include, in addition to monomers having a (meth)acryloyl group. Ethylene-unsaturated carboxylic acids (e.g., maleic acid, itaconic acid); Styrene compounds (e.g., styrene, alpha-methylstyrene, vinyltoluene); Saturated vinyl fatty acids (e.g., vinyl acetate, vinyl propionate); Vinyl compounds (e.g., 1,4-divinyloxybutane, divinylbenzene, etc.); Allyl compounds (e.g., diallyl phthalate, triallyl cyanurate, etc.) These are some examples.

[0043] Examples of bifunctional or more monomers that may be copolymerized include: Diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, propylene glycol di(meth)acrylate, N,N'-methylenebis(acrylamide), and other polyfunctional (meth)acrylates, Polyfunctional acrylamide These are some examples.

[0044] In particular, from the viewpoint of lowering the Tg of the resin particles, the monomer having a (meth)acryloyl group preferably includes alkyl acrylates, more preferably C4-12 alkyl acrylates, and even more preferably n-butyl acrylate and 2-ethylhexyl acrylate. Furthermore, from the viewpoint of friction resistance, the monomer having a (meth)acryloyl group preferably includes methacrylic acid esters such as methyl methacrylate, or acrylonitrile. These may be included individually or in combination of two or more types.

[0045] Furthermore, it is preferable that the monomers constituting the (meth)acrylic resin contain compounds (crosslinkable monomers) that have crosslinkable groups that react with crosslinking agents contained in the ink or post-treatment liquid. That is, it is preferable that the (meth)acrylic resin further has crosslinkable groups. Since the (meth)acrylic resin having crosslinkable groups can react with crosslinking agents contained in the ink or post-treatment liquid and undergo post-crosslinking, it can suppress stickiness on the surface of the fabric.

[0046] As described above, any polymerizable compound having a crosslinking group that reacts with the crosslinking agent can be used. For example, when using a crosslinking agent that reacts with a hydroxyl group, monomers having a hydroxyl group, specifically hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate, can be used. When using a crosslinking agent that reacts with a carboxyl group, monomers having a carboxyl group, specifically (meth)acrylic acid and maleic acid, can be used. When using a crosslinking agent that reacts with a ketone group, monomers having a ketone group can be used. Specifically, diacetone acrylamide (DAAM) can be used.

[0047] The content of structural units derived from crosslinkable monomers is preferably 0.1 to 30% by mass, and more preferably 1 to 10% by mass, relative to the total structural units constituting the resin. If the content of structural units derived from crosslinkable monomers is above the lower limit, the resin constituting the resin particles can be further crosslinked. If the content of structural units derived from crosslinkable monomers is below the upper limit, excessive post-crosslinking is less likely to occur, which can further reduce wear on the surface of the image-formed product and further reduce the impairment of frictional fastness.

[0048] Alternatively, the (meth)acrylic resin may be pre-crosslinked. The crosslinked (meth)acrylic resin may be a copolymer of a monofunctional vinyl monomer containing at least one of (meth)acrylic acid ester and (meth)acrylonitrile and a polyfunctional vinyl monomer. This is because the crosslinked (meth)acrylic resin is less likely to fuse and form a film during drying, for example, after the application of a post-treatment solution.

[0049] Furthermore, the resin particles may be composite particles containing two or more types of resin, for example, core-shell particles having a core layer and a shell layer. Specifically, the resin particles may have a core layer containing a copolymer of alkyl acrylate, methyl methacrylate, and a crosslinkable monomer, and a shell layer containing a copolymer of alkyl acrylate, methyl methacrylate, and a monomer having a dispersible group such as an ethylenically unsaturated carboxylic acid.

[0050] The average particle size of the resin particles may be, for example, 80 to 400 nm, preferably 150 to 300 nm. The average particle size of the resin particles can be measured in the same way as the average particle size of the pigment particles.

[0051] The resin particle content is preferably 0.1 to 30% by mass relative to the ink, and more preferably 1 to 20% by mass. If the resin particle content is above the lower limit, the ink's adhesion to the fabric is more easily improved. If the resin particle content is below the upper limit, the fabric will not become too stiff, and the texture of the fabric will be less likely to be damaged. The resin particles may be of one type or two or more types.

[0052] 1-3. Other ingredients 1-3-1. Crosslinking agent As described above, the ink preferably further contains a crosslinking agent for crosslinking the resins that make up the resin particles.

[0053] The crosslinking agent is preferably a compound having at least two functional groups in its molecule that react with the crosslinkable groups (hydroxyl groups, carboxyl groups, ketone groups) present in the resin particles. 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; and examples of crosslinking groups that react with ketone groups include hydrazide groups.

[0054] Specifically, examples of crosslinking agents that react with hydroxyl groups include Fixer N (block isocyanate-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.); examples of crosslinking agents that react with carboxyl groups include Fixer F (aziridine-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.); and examples of crosslinking agents that react with ketone groups include adipic acid dihydrazide (ADH, hydrazine-based crosslinking agent).

[0055] From the viewpoint of being able to be stored at room temperature for a long period of time and being able to crosslink at room temperature, adipic acid dihydrazide is the most preferred, and the combination with the crosslinkable monomer diacetone acrylamide (DAAM) that reacts with it is the most preferred.

[0056] The crosslinking agent content in the ink is not particularly limited, but it is preferable that it is greater than the crosslinking agent content in the post-treatment solution. This makes it easier to form a concentration gradient of the crosslinking agent between the ink and the post-treatment solution, allowing the crosslinking density to decrease as it approaches the surface of the image. As a result, the surface of the image does not become too hard, further reducing surface wear and making it easier to maintain frictional fastness over a longer period. When the crosslinking agent content in the ink is m1 (parts by mass) and the crosslinking agent content in the post-treatment solution is m2 (parts by mass), the ratio m2 / m1 is preferably 0.2 to 1. The crosslinking agent content m1 in the ink is preferably, for example, 0.1 to 3% by mass relative to the ink, and more preferably 0.2 to 2% by mass.

[0057] 1-3-2. Solvent The solvent is not particularly limited, but it is preferably water, and more preferably a water-soluble organic solvent.

[0058] The water content is, for example, 20 to 70% by mass relative to the ink, preferably 30 to 60% by mass.

[0059] While there are no particular restrictions on water-soluble organic solvents as long as they are compatible with water, it is preferable that the ink does not thicken easily upon drying, from the viewpoint of facilitating the penetration of the ink into the fabric and minimizing the loss of injection stability in inkjet printing. Therefore, it is preferable that the ink contains a high-boiling-point solvent with a boiling point of 200°C or higher.

[0060] The high-boiling-point solvent with a boiling point of 200°C or higher can be any water-soluble organic solvent with a boiling point of 200°C or higher, and is preferably a polyol or polyalkylene oxide.

[0061] Examples of polyols with a boiling point of 200°C or higher include divalent alcohols such as 1,3-butanediol (boiling point 208°C), 1,6-hexanediol (boiling point 223°C), and polypropylene glycol; and trivalent or higher alcohols such as glycerin (boiling point 290°C) and trimethylolpropane (boiling point 295°C).

[0062] Examples of polyalkylene oxides with a boiling point of 200°C or higher include 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 ethers of divalent alcohols such as polypropylene glycol, as well as ethers of trivalent or higher alcohols such as glycerin (boiling point 290°C) and hexanetriol.

[0063] The solvent may further include other solvents besides the high-boiling point solvents mentioned above. Examples of other solvents include polyhydric alcohols with a boiling point of less than 200°C (e.g., ethylene glycol, propylene glycol, hexanetriol, etc.); polyhydric alcohol ethers with 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, etc.). This includes diethanolamines; amines (e.g., ethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine); amides (e.g., formamide, N,N-dimethylformamide, N,N-dimethylacetamide); heterocyclic compounds (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., sulfolanes).

[0064] The content of the water-soluble organic solvent is, for example, 20 to 70% by mass relative to the ink, preferably 30 to 60% by mass.

[0065] 1-3-3. Other Additives The above inks may contain other components as needed. Examples of other components include pigment dispersants, surfactants, preservatives, fungicides, pH adjusters, etc.

[0066] (Pigment dispersant) Pigment dispersants exist in the ink either surrounding the surface of pigment particles or adsorbed onto the surface of pigment particles to form a pigment dispersion, thereby effectively dispersing the pigment. From the viewpoint of excellent pigment dispersibility, such pigment dispersants are preferably polymeric dispersants. Examples of polymeric dispersants include anionic dispersants and cationic dispersants.

[0067] Anionic dispersants can be polymeric dispersants having hydrophilic groups selected from the group consisting of carboxylic acid groups, phosphorus-containing groups, and sulfonic acid groups. Among these, polymeric dispersants having carboxylic acid groups are preferred.

[0068] Examples of polymeric dispersants having a carboxylic acid group include polycarboxylic acids or salts thereof. Examples of polycarboxylic acids include (co)polymers of monomers selected from acrylic acid or its derivatives, maleic acid or its derivatives, itaconic acid or its derivatives, fumaric acid or its derivatives, and salts thereof. Examples of other monomers that make up copolymers include styrene and vinylnaphthalene.

[0069] The anionic group equivalent of the anionic dispersant is not particularly limited, as long as it is sufficient to adequately disperse the pigment particles, but it is preferably in the range of 1.1 to 3.8 meq / g. When the anionic group equivalent is within the above range, high pigment dispersibility can be easily obtained without increasing the molecular weight of the anionic dispersant. The anionic group equivalent can be measured by the same method as the method for measuring the acid value.

[0070] Examples of cationic groups in cationic dispersants include secondary amino groups (imino groups), tertiary amino groups, or quaternary ammonium groups. The cationic dispersant is not particularly limited as long as it can form the pigment dispersion described above.

[0071] The amount of polymer dispersant should be within a range that allows for sufficient dispersion of pigment particles while maintaining a viscosity that does not impair penetration into the fabric. For example, it should be 20 to 100% by mass, preferably 25 to 60% by mass, relative to the pigment.

[0072] (Surfactants) Surfactants can lower the surface tension of ink, thereby increasing its wettability to fabrics. The type of surfactant is not particularly limited, but examples include acetylene glycol-based surfactants, silicone-based surfactants, and fluorine-based surfactants.

[0073] (Preservatives, fungicides) Examples of preservatives or fungicides include aromatic halogen compounds (e.g., Preventol CMK), methylenedithiocyanates, halogenated nitrogen-sulfur compounds, and 1,2-benzisothiazolin-3-one (e.g., PROXEL GXL).

[0074] (pH adjuster) Examples of pH adjusters include citric acid, sodium citrate, hydrochloric acid, and sodium hydroxide.

[0075] 1-4. Physical properties of ink The viscosity of the above ink at 25°C is not particularly limited, as long as it is sufficient for good ejection by the inkjet method, but it is preferably 3 to 20 mPa·s, and more preferably 4 to 12 mPa·s. The viscosity of the ink can be measured at 25°C using an E-type viscometer.

[0076] The surface tension of the ink at 25°C is preferably 36-50 mN / m, and more preferably 38-45 mN / m. The lower the surface tension of the ink, the easier it is to wet and spread, but capillary penetration is less likely to occur (the ink is less likely to penetrate into the interior of the fabric). If the surface tension of the ink is within the above range, the ink will wet and spread more easily, and capillary action will also occur more easily. Specifically, it is possible to make it easier for solvent components such as water to penetrate between the fibers, while making it difficult for resin particles to penetrate. As a result, it is possible to suppress the deterioration of texture while maintaining friction fastness. The surface tension of the ink can be easily measured by the plate method (Wilhelmy method).

[0077] The surface tension of the ink can be adjusted, for example, by the amount of surfactant it contains or the composition of the organic solvent.

[0078] 1-5. Ink preparation The above ink can be manufactured by any method. For example, the above ink may be manufactured by 1) mixing a pigment, a pigment dispersant, and a solvent to obtain a pigment dispersion, and 2) further mixing the obtained pigment dispersion with a dispersion containing resin particles and any other component (e.g., a crosslinking agent or a surfactant).

[0079] 2. Post-treatment solution The post-treatment liquid according to this embodiment contains a lubricant.

[0080] 2-1. Lubricant Lubricants can impart slipperiness to the surface of image-formed objects and enhance frictional durability. As described above, any lubricant that has a ΔSP (Depth Shift Point) with respect to resin particles contained in the ink within a predetermined range is acceptable.

[0081] Examples of lubricants include plant and animal waxes such as carnauba wax, candelilla wax, beeswax, rice wax, and lanolin; petroleum waxes such as paraffin wax, microcrystalline wax, polyolefin wax (e.g., polyethylene wax, polypropylene wax), oxidized polyolefin wax (e.g., oxidized polyethylene wax), and petrolatum; mineral waxes such as montane wax and ozokerite; synthetic waxes such as carbon wax, Hoechst wax, polyolefin wax, stearic acid amide, and α-olefin-maleic anhydride copolymers; and organosilicon compounds. Among these, organosilicon compounds are preferred from the viewpoint of easily adjusting the ΔSP with the resin particles to a predetermined range when the resin particles contained in the ink include (meth)acrylic resin particles.

[0082] The organosilicon compound is preferably a silicone resin. The silicone resin may be in the form of an oil, latex, or resin. The silicone resin is preferably a silicone acrylic resin.

[0083] Silicone acrylic resin is a copolymer containing siloxane structural units and (meth)acrylic acid ester structural units.

[0084] The content of structural units derived from (meth)acrylic acid ester is not particularly limited, but is preferably 20 to 80% by mass, and more preferably 30 to 70% by mass, relative to the total structural units constituting the copolymer. If the content of structural units derived from (meth)acrylic acid ester is above the lower limit, for example, if the resin particles contained in the ink are (meth)acrylic resin, it is easier to moderately reduce ΔSP. This makes it easier to gradually diffuse the lubricant to the surface of the image-forming material, and good frictional fastness can be maintained over a long period of time. If the content of structural units derived from (meth)acrylic acid ester is below the upper limit, ΔSP does not become too small, so the rate at which the lubricant diffuses to the surface of the image-forming material does not become too slow, and good frictional fastness can be easily obtained from the beginning.

[0085] Examples of commercially available silicone resins include Charine FE502 and E-370 (manufactured by Nisshin Chemical Industry Co., Ltd., silicone-acrylic polymers), and Cymac US-450 and US-480 (manufactured by Toagosei Co., Ltd., silicone-acrylic polymers).

[0086] The lubricant content is not particularly limited, but is preferably 0.1 to 10% by mass relative to the post-treatment solution, and more preferably 0.5 to 5% by mass. If the lubricant content is above the lower limit, it is easier to impart more slipperiness to the surface of the image-formed object, and the frictional fastness can be further enhanced. If the lubricant content is below the upper limit, the surface is less likely to peel off, and the frictional fastness is less likely to be impaired.

[0087] 2-2. Other ingredients The post-treatment solution may further contain other components besides the lubricant, as needed. Examples of other components include resin particles, crosslinking agents, solvents (including water), and other additives.

[0088] 2-2-1. Resin particles The resin particles used can be the same as those used in ink. The resin particles contained in the post-treatment solution may be the same type as those contained in ink, or they may be different types. However, from the viewpoint of making it easier to form a continuous layer, it is preferable that they be the same type, and more preferably (meth)acrylic resin particles.

[0089] The resin particle content in the post-processing solution is preferably less than the resin particle content in the ink. This is because the surface of the image-formed object does not become too hard, thus further reducing wear and improving frictional durability. When the resin particle content in the ink is M1 (parts by mass) and the resin particle content in the post-processing solution is M2 (parts by mass), M2 / M1 is preferably 0.1 to 0.8. Specifically, the resin particle content in the post-processing solution is, for example, 1 to 20% by mass, preferably 3 to 8% by mass, relative to the post-processing solution. If the resin particle content is 1% by mass or more, the lubricant adhesion is more easily improved. If the resin particle content is 20% by mass or less, the surface of the image-formed object does not become too hard, thus further reducing wear.

[0090] 2-2-2. Crosslinking agents The crosslinking agent can be the same as the one used in the ink. As described above, it is preferable that the crosslinking agent content m1 in the post-treatment solution is less than the crosslinking agent content m2 in the ink. This is because the crosslinking density of the resin particles on the surface of the image-forming product does not become relatively too high, thus further reducing the impact on frictional fastness. The crosslinking agent content m2 in the post-treatment solution is preferably 0.1 to 3% by mass, and more preferably 0.2 to 2% by mass, relative to the post-treatment solution.

[0091] 2-2-3. Solvents and other additives The solvents and other additives used can be the same as those used in inks.

[0092] 2-2-4. Physical Properties From the same viewpoint as above, the surface tension of the post-treatment solution at 25°C is preferably 32 to 60 mN / m, and more preferably 37 to 50 mN / m.

[0093] These inks and post-treatment solutions can be used as an ink set.

[0094] 3.Image forming method An image forming method according to one embodiment of the present invention includes the steps of applying ink to a fabric using an inkjet method and applying a post-treatment liquid to the ink applied to the fabric using a wet-on-wet method. The ink and post-treatment liquid used are those described above.

[0095] 3-1. Ink application process Ink is ejected from the inkjet recording head, and droplets of ink are applied to the fabric.

[0096] The fibers that make up the fabric are not particularly limited, but include natural fibers such as cotton (cellulose fibers), linen, wool, and silk; chemical fibers such as rayon, vinylon, nylon, acrylic, polyurethane, polyester, or acetate, and blends thereof. Among these, it is preferable that the fabric contains hydrophilic fibers such as cotton and hydrophobic fibers such as polyester.

[0097] Hydrophobic fibers, such as polyester, tend to repel liquids, while hydrophilic fibers, such as cotton and linen, allow liquids to penetrate easily. By using a blend of these fibers, water and solvents preferentially penetrate between the hydrophilic fibers, resulting in a greater accumulation of resin particles on the hydrophilic fibers. In other words, minute irregularities are formed on the surface of the image-forming material, further improving friction fastness without compromising texture.

[0098] The fabric may be made from these fibers in any form, such as woven, nonwoven, or knitted. Furthermore, the fabric may be a blended woven or nonwoven fabric of two or more types of fibers.

[0099] 3-2. Step of applying post-treatment solution Next, a post-treatment solution is applied to the ink on the fabric using a wet-on-wet method.

[0100] As described above, the application method using the wet-on-wet method is preferable, but it is especially desirable to adjust the time between applying the ink droplets and applying the post-treatment solution (application interval).

[0101] The interval between applying the ink droplet and applying the post-treatment liquid is preferably 0.1 to 5 seconds when the surface temperature of the fabric is 40°C or lower, preferably 30 to 40°C. When an ink droplet is applied, evaporation occurs from the moment it hits the fabric, and penetration into the fabric occurs, increasing the viscosity of the liquid. If the interval before applying the post-treatment liquid is 5 seconds or less, the viscosity difference at the interface between the ink and the post-treatment liquid does not become large, making it difficult for an interface to form and further reducing frictional damage at the interface. If the interval is 0.1 seconds or more, the ink and post-treatment liquid do not mix uniformly, making it easier to form a concentration gradient of the lubricant in the thickness direction, and making it easier to obtain long-term frictional fastness.

[0102] The application of the post-treatment solution is not particularly limited as long as it is possible to apply it by the wet-on-wet method described above, for example, by spraying or by inkjet printing.

[0103] The amount of post-treatment solution applied is not particularly limited, but preferably 1 to 120 g / m² 2 , comfortable 10~60g / m 2 This is possible. If the amount of post-treatment liquid applied is within the above range, it is possible to further impart slipperiness to the fabric without damaging its texture and to further enhance its frictional resistance.

[0104] 3-3. Other processes The above image forming method may further include other steps as needed. For example, a step of pre-treating the fabric (pre-treatment step) may be performed before the step of applying the ink, or a step of drying the post-treatment liquid or post-crosslinking the resin particles (drying and post-crosslinking step) may be performed after the step of applying the post-treatment liquid.

[0105] 3-3-1. Pre-treatment process In this process, the fabric may be pre-treated by bringing it into contact with a pre-treatment solution.

[0106] The type of pretreatment solution is not particularly limited and can be selected according to the composition of the ink. For example, if the ink contains an anionic dispersant, the pretreatment solution preferably contains a compound having an acidic or cationic group. If the ink contains a cationic dispersant, the pretreatment solution preferably contains a compound having an anionic group.

[0107] Compounds having cationic groups can act as flocculants that aggregate ink components. Examples of compounds having cationic groups include polyvalent metal salts, organic acids, cationic resins, and cationic surfactants. Among these, polyvalent metal salts, organic acids, or cationic resins are preferred from the viewpoint of excellent reactivity with pigments and resin particles contained in the ink, with polyvalent metal salts and cationic resins being more preferred.

[0108] Polyvalent metal salts can be water-soluble compounds containing a polyvalent metal ion with two or more valencies and an anion that binds to it. 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 trivalent metal ions include Cl. - , I - , Br - SO4 2- ClO3 - NO3 - , and HCOO - CH3COO - Examples include calcium salts and magnesium salts, with calcium nitrate and calcium chloride being preferred. Examples of cationic resins include cationic urethane resins, cationic olefin resins, and cationic allylamine resins.

[0109] The compound having anionic groups is not particularly limited and may be similar to anionic surfactants or may be a polymer compound having anionic groups. Examples of polymer compounds having anionic groups include plant peels such as pectin, cellulose derivatives such as carboxymethylcellulose, modified starches such as carboxymethyl starch and carboxyethyl starch, and synthetic adhesives such as acrylic polymers (acrylic polymers using acrylic acid as a copolymer component, such as acrylic acid-acrylic acid ester copolymers and styrene-acrylic acid copolymers).

[0110] The pretreatment solution may further contain pH adjusters, preservatives, etc., as needed. The pH adjusters and preservatives used are the same as those used in the ink.

[0111] There are no particular restrictions on the amount of pretreatment solution applied, but for example, 5-70 g / m² is acceptable. 2 , more preferably 20-60 g / m 2 It could be.

[0112] The method for bringing the fabric into contact with the pretreatment solution is not particularly limited, but may include, for example, a pad method, a coating method, a spray method, or an inkjet method.

[0113] The pretreatment solution applied to the fabric may be heated and dried using hot air, a hot plate, or a heat roller.

[0114] 3-3-2. Drying and Post-Crosslinking Process In the drying and post-crosslinking process, solvents and other substances contained in the post-treatment liquid applied to the fabric are removed and the fabric is dried, or the resin constituting the resin particles is crosslinked (post-crosslinked). In particular, when the Tg of the resin constituting the resin particles is low, post-crosslinking is preferable from the viewpoint of suppressing stickiness.

[0115] The drying method is not particularly limited and may be carried out at room temperature or by heating. The heating method may be a method using a heater, a hot air dryer, a heating roller, etc. Preferably, a method is used in which a hot air dryer and a heater are used to heat both sides of the fabric.

[0116] 3-4. Image Formation The resulting image-forming product includes a fabric and a continuous layer of ink and post-treatment solution placed on the fabric. The continuous layer includes components derived from the ink (pigment particles, resin particles) and components derived from the post-treatment solution (lubricant).

[0117] In a continuous layer, there is no clear interface between the ink and the post-treatment, and the composition changes continuously in the thickness direction. This state can be observed, for example, with an optical microscope or an electron microscope. For example, lubricants and resin particles can be distributed in the thickness direction of the continuous layer so that they gradually increase from the inside to the surface of the fabric. This prevents the layer containing the lubricant from peeling off due to friction, thus maintaining friction fastness over a long period of time.

[0118] Furthermore, when resin particles are post-crosslinked, the crosslinking density is lower on the surface of the image-forming material than in the interior, within the thickness direction of the continuous layer. As a result, the surface of the image-forming material does not become too hard, leading to less wear and less loss of frictional durability.

[0119] In the above embodiment, the post-treatment solution is applied wet-on-wet, but the ink may also be applied wet-on-wet. That is, after applying the pre-treatment solution to the fabric, the ink and post-treatment solution may be applied sequentially before the applied pre-treatment solution dries completely. This allows the pre-treatment solution, ink, and post-treatment solution to form a continuous layer without boundaries, thus enabling further improvement in durability, such as friction fastness. In this case as well, the time between the application of the pre-treatment solution and the application of the ink (coating interval) can be the same as described above. [Examples]

[0120] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0121] 1. Materials of ink and post-treatment solution 1-1. Preparation of anionic pigment dispersion As a pigment dispersant, 7 parts by mass of styrene-butyl acrylate-methacrylic acid copolymer (anionic dispersant, weight-average molecular weight 16000, anionic group equivalent 3.5 meq / g) was mixed with 78 parts by mass of water, and then heated and stirred to prepare a neutralized pigment dispersant. To this mixture, 15 parts by mass of CI pigment blue 15:3 was added and pre-mixed, and then dispersed using a sand grinder packed with 0.5 mm zirconia beads at a volume percentage of 50% to obtain a cyan pigment dispersion with a pigment concentration of 15% by mass.

[0122] 1-2. Preparation of resin particle dispersion <Preparation of resin particle dispersion A> (Single particle fabrication) A separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device was filled with an activator solution prepared by dissolving 1.68 g of anionic activator (sodium dodecylbenzenesulfonate: SDS) and 0.34 g of sodium carbonate in 320 g of deionized water. The solution was then stirred at a rate of 330 rpm under a nitrogen stream, and the internal temperature was raised to 80°C.

[0123] On the other hand, a monomer solution was prepared by dissolving 70 parts by mass of n-butyl acrylate (BA), 15 parts by mass of methyl methacrylate (MMA), 10 parts by mass of methacrylic acid, 5 parts by mass of diacetone acrylamide (DAAM) as a crosslinkable monomer, and 0.005 parts by mass of 1-octanthiol (NOM) as a water-soluble chain transfer agent.

[0124] Next, a solution prepared by dissolving 0.14 g (0.001 parts by mass) of polymerization initiator (potassium persulfate: KPS) in 2.66 g of deionized water was added, and the mixture was heated at 80°C. The prepared monomer solution was then added dropwise over 60 minutes and stirred to prepare a resin particle dispersion A containing copolymer particles (BA / MMA / MAA / DAAM = 70 / 15 / 10 / 5 by mass ratio) with a solid content of 30%. (Resin particle dissolution parameter SP1) The dissolution parameter SP1 of the resin particles was measured using the following procedure. 1) The degree of swelling of resin particles was measured when immersed in each of the following solutions: hexane (solubility parameter 7.24), toluene (solubility parameter 8.91), ethyl acetate (solubility parameter 9.10), acetone (solubility parameter 9.77), and methanol (solubility parameter 14.28). The degree of swelling (%) was calculated using the following formula, with W1 being the weight of the dry resin particles and W2 being the weight after immersion in each solvent at 100% concentration at room temperature for 120 minutes. Swelling degree (%) = (W2 - W1) / W1 × 100 2) Next, a graph was created with the SP value of the solvent on the X-axis and the degree of swelling on the Y-axis, and an approximate curve was obtained using Gaussian approximation (normal distribution approximation). The SP values ​​of the solvent were taken from "Fundamentals and Engineering of Coatings" by Yuji Harasaki, p. 53, Japan Processing Technology Association, 2010. 3) Next, the peak of the approximation curve obtained in 2) above (the SP value of the solvent at which the degree of swelling is maximized) was taken as the SP value of the resin particle. The SP1 value measured using the above method was 9.1, and the Tg of the resin particles was -18°C.

[0125] <Preparation of resin particle dispersion B> (Core particle fabrication) A separable flask equipped with a stirrer, temperature sensor, condenser, and nitrogen introduction device was filled with an activator solution prepared by dissolving 1.68 g of an anionic activator (sodium dodecylbenzenesulfonate: SDS) and 0.52 g of sodium carbonate in 320 g of deionized water. The solution was then stirred at a rate of 330 rpm under a nitrogen stream, and the internal temperature was raised to 80°C.

[0126] On the other hand, a monomer solution was prepared by dissolving 70 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), 15 parts by mass of hydroxyethyl methacrylate (HEMA), 5 parts by mass of diacetone acrylamide (DAAM) as a crosslinkable monomer, and 0.004 parts by mass of 1-octanthiol (NOM) as a water-soluble chain transfer agent.

[0127] Next, a solution prepared by dissolving 0.14 g (0.001 parts by mass) of polymerization initiator (potassium persulfate: KPS) in 2.66 g of deionized water was added, and the mixture was heated at 80°C. The prepared monomer solution was then added dropwise and stirred over 60 minutes to produce core particles (BA / MMA / HEMA / DAAM65 / 15 / 15 / 5 by mass ratio).

[0128] Furthermore, since the amount of the core layer was greater than the amount of the shell layer, the core particles of the resin were prepared separately, and the SP1 value was measured, resulting in a value of 9.4.

[0129] <Preparation of resin particle dispersion C> Resin particle dispersion C was prepared in the same manner as resin particle dispersion B, except that the type and amount of monomers used were changed to prepare copolymer particles of n-butyl methacrylate (BMA) / 2-ethylhexyl acrylate / diacetone acrylamide (DAAM) = 60 / 35 / 5 (mass ratio). Core particles were synthesized separately in the same manner, and the solubility parameter SP1 was measured. The result showed an SP1 of 8.6 and a Tg of -8°C.

[0130] <Resin particle dispersion D> Resin particle dispersion A and resin particle dispersion D were prepared in the same manner as resin particle dispersion A, except that resin particle dispersion D was prepared by dissolving 60 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), 20 parts by mass of hydroxyethyl methacrylate (HEMA), 5 parts by mass of methacrylic acid, and 0.004 parts by mass of 1-octanthiol (NOM) as a water-soluble chain transfer agent in a monomer solution. SP1 was 9.8 and Tg was -14℃.

[0131] <Resin particle dispersion E> Unitika's Elitel KT-0507 (polyester particle dispersion). SP1 was 10.0.

[0132] 1-3. Crosslinking agents Dihydrazide adipic acid (ADH, water-soluble crosslinking agent) Fixer F (aziridine-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.) Fixer N (block isocyanate-based crosslinking agent, manufactured by Matsui Pigment Chemical Industry Co., Ltd.)

[0133] 1-4. Lubricant Lubricant 1: Charline FE502 (manufactured by Nisshin Chemical Industry Co., Ltd., silicone-acrylic polymer, silicone / acrylic = 5 / 5 mass ratio, SP value: 8.4) Lubricant 2: Charline R-170BX (manufactured by Nisshin Chemical Industry Co., Ltd., silicone-acrylic polymer, silicone / acrylic = 3 / 7 mass ratio, SP value: 8.7) Lubricant 3: Paraffin wax (SP value 8.1) Lubricant 4: Polyethylene wax (SP value 8.0) Lubricant 5: Silicone wax (SP value 7.5)

[0134] 1-5. Organic solvents Ethylene glycol Propylene glycol Glycerin

[0135] 1-6. Other ingredients Olphine E1010 (manufactured by Nisshin Chemical, acetylene glycol-based surfactant): 0.1 parts by mass Proxel GXL (manufactured by Lonza Japan, antifungal agent): 0.5 parts by mass

[0136] 2. Ink preparation <Preparation of Ink 1> Next, the following components were mixed to a total of 100 parts by mass to obtain ink 1. Anionic pigment dispersion (pigment concentration 15% by mass): 10 parts by mass (solid content 1.5 parts by mass) Resin particle dispersion liquid A (solid content concentration 30% by mass): 35 parts by mass (solid content 10.5 parts by mass) Dihydrazide adipic acid (crosslinking agent): 0.7 parts by mass Ethylene glycol: 25 parts by mass Propylene glycol: 10 parts by mass Glycerin: 10 parts by mass Olphine E1010 (manufactured by Nisshin Chemical, acetylene glycol-based surfactant): 0.1 parts by mass Proxel GXL (manufactured by Lonza Japan, antifungal agent): 0.5 parts by mass Deionized water: Remaining portion

[0137] <Preparation of inks 2-13> Inks 2-13 were prepared in the same manner as Ink 1, except that some of the components of the ink were changed as shown in Table 1.

[0138] <Measurement> The SP values ​​of the resin particles used in the preparation of inks 1 to 13 and the surface tension of the inks were calculated or measured by the following methods.

[0139] (Measurement of surface tension) The surface tension of the ink was measured at 25°C using the plate method (Wilhelmy method).

[0140] The measurement results for inks 1-13 are shown in Table 1. [Table 1]

[0141] 3. Preparation of post-treatment solution <Preparation of post-treatment solution 1> Next, the following components were mixed to a total of 100 parts by mass to obtain post-treatment liquid 1. Resin particle dispersion liquid A (solid content concentration 30% by mass): 16.7 parts by mass (solid content 5 parts by mass) Dihydrazide adipic acid (crosslinking agent): 0.2 parts by mass Lubricant 1: 1.5 parts by mass Ethylene glycol: 25 parts by mass Propylene glycol: 10 parts by mass Glycerin: 15 parts by mass Olphine E1010 (manufactured by Nisshin Chemical, acetylene glycol-based surfactant): 0.1 parts by mass Proxel GXL (manufactured by Lonza Japan, antifungal agent): 0.5 parts by mass Deionized water: Remaining portion

[0142] <Preparation of post-treatment solutions 2-16> Post-treatment solutions 2 to 16 were prepared in the same manner as post-treatment solution 1, except that the composition of the post-treatment solution was changed as shown in Table 2.

[0143] <Measurement> The surface tensions of post-treatment solutions 1 to 16 were measured using the same method as described above. The solubility parameter SP2 of the lubricant used in preparing the post-treatment solutions was also determined using the same method as the solubility parameter SP1 of the resin particles. However, the type and number of solvents used to measure the swelling degree of the lubricant were the same as those used to measure the swelling degree of the resin particles. The measurement results for post-treatment solutions 1-16 are shown in Table 2. [Table 2]

[0144] 4. Preparation of pretreatment solution The following components were mixed to a total of 100 parts by mass to obtain a pretreatment solution. PAS-H-1L (manufactured by Nitto Medical Co., Ltd., polydiallyldimethylammonium chloride, cationizing agent): 5 parts by mass Ethylene glycol: 20 parts by mass Propylene glycol: 10 parts by mass Glycerin: 15 parts by mass Olphine E1010 (manufactured by Nisshin Chemical, acetylene glycol-based surfactant): 0.1 parts by mass Proxel GXL (manufactured by Lonza Japan, antifungal agent): 0.5 parts by mass Deionized water: Remaining portion

[0145] 5. Image formation tests and evaluation <Exam 1, 3-18, 20-27> (Image formation test) As the fabric, TC broadcloth (a blend of polyester and cotton, 75% and 25% cotton) was prepared. Next, an image formation test was performed using the pre-treatment solution, ink, and post-treatment solution prepared above. First, an inkjet head (Konica Minolta head #204) was prepared as the image forming apparatus. This head has a head for pre-treatment solution, an ink head, and a head for post-treatment solution. The prepared pre-treatment solution, the ink listed in Table 3, and the post-treatment solution were set up so that they could be ejected from their respective heads, and a sample was prepared by solid printing on the fabric in the order of pre-treatment solution, ink, and post-treatment solution. During the application process, the surface temperature of the fabric was adjusted to 25°C. The application conditions were as follows.

[0146] The pretreatment agent and each color ink were ejected using a main scan resolution of 540 dpi × sub-scan resolution of 720 dpi. dpi represents the number of ink droplets (dots) per 2.54 cm. The ejection frequency was set to 22.4 kHz.

[0147] The post-treatment solution was applied using a wet-on-wet method. Specifically, the application interval between dispensing the ink droplet and dispensing the post-treatment solution was set to 0.2 seconds. At this time, the ratio of (amount of ink remaining at the time of post-treatment solution application) / (amount of ink applied) per unit area of ​​the recording area was 0.8. The amount of post-treatment solution applied was 15 g / m². 2 The procedure was carried out under conditions that would result in the following outcome.

[0148] Then, the fabric treated with the post-treatment solution was dried and cross-linked in a belt-carrying dryer at 120°C for 3 minutes to obtain an image-formed product.

[0149] <Exam 2> An image-forming object was obtained in the same manner as in Test 1, except that after applying the pretreatment solution, droplets of ink and droplets of posttreatment solution were dispensed simultaneously (with a coating interval of 0 seconds).

[0150] <Exam 19> An image-forming product was obtained in the same manner as in Test 1, except that after applying ink droplets, the product was heated with an infrared heater to dry the volatile components of the applied ink, and then droplets of post-treatment solution were applied (coated wet-on-dry).

[0151] <Rating> The dry friction fastness and texture of the obtained image formations were evaluated by the following method.

[0152] (Texture) The resulting image formations were evaluated by sensory assessment using tactile feedback and assessed according to the following criteria. ○: Soft and the boundary between the printed surface and the fabric is indistinguishable. △: It's soft and not stiff, but the boundary between the printed surface and the fabric is noticeable. ×: It has a rough and stiff texture. A score of △ or higher was considered acceptable.

[0153] (Abrasion resistance) The obtained image formations were left for one month under xenon lamp conditions of 25°C and 50% RH (Super Xenon Weather Meter SX75, Suga Testing Machine Co., Ltd.). Subsequently, a JSPS-type friction fastness tester (product name: AB-301, manufactured by Tester Sangyo Co., Ltd.) was used to perform 100.0 cycles under conditions of a load of 200.0 g and a speed of 10.0 cm / s. After that, pure water was impregnated into a JIS color fastness test cloth (JIS L 0803:2011 compliant No. 3-1), and the optical density value of the color transfer (hereinafter also referred to as "color transfer density OD value") was measured, and the friction fastness was evaluated according to the following evaluation criteria. A lower color transfer density OD value indicates better friction fastness (wet friction fastness). ◎: The OD value of the transfer concentration is 0.15 or less. ○: The OD value of the transfer concentration is greater than 0.15 and less than or equal to 0.20. △: The OD value of the transfer concentration is greater than 0.20 and less than or equal to 0.25. ×: The OD value of the transfer concentration is greater than 0.25. A score of △ or higher was considered acceptable.

[0154] The evaluation results for tests 1-29 are shown in Table 3.

[0155] [Table 3]

[0156] As shown in Table 3, in tests 1-9 and 11-21, where a post-treatment solution was applied using a wet-on-wet method and the difference in SP values ​​ΔSP between the resin particles of the ink and the lubricant of the post-treatment solution was 0.3-0.8, it can be seen that image-forming products with high dry friction durability over a long period of time were obtained while maintaining a good texture.

[0157] In contrast, in Test 21, where the post-treatment solution was applied using the wet-on-dry method, both dry friction fastness and texture were found to be low. Furthermore, even when the post-treatment solution was applied using the wet-on-wet method, in Tests 22-24, 26, and 28-29, where the difference in SP values ​​ΔSP between the resin particles of the ink and the lubricant of the post-treatment solution exceeded 0.8, long-term dry friction durability was found to be low. In addition, in Test 27, where the difference in SP values ​​ΔSP between the resin particles of the ink and the lubricant of the post-treatment solution was less than 0.3, long-term friction durability was also found to be low.

[0158] <Tests 30-34> Image formation was performed in the same manner as in Test 1, except that the interval between the ejection of ink droplets and the start of ejection of the post-treatment solution was changed as shown in Table 4.

[0159] Then, the same evaluations as above (dry friction fastness, texture) were performed. The results are shown in Table 4.

[0160] [Table 4]

[0161] As shown in Table 4, by setting the application interval to 0.1 to 5 seconds, the texture of the fabric is less likely to be damaged, and the friction fastness is further improved. [Industrial applicability]

[0162] According to the present invention, it is possible to provide an image forming method that can maintain high frictional fastness over a long period of time without impairing the texture of the fabric.

Claims

1. A process of applying an ink containing pigment and resin particles onto a fabric using an inkjet method, The process includes applying a post-treatment solution containing a lubricant to the ink applied to the aforementioned fabric in a wet-on-wet manner. The glass transition temperature of the resin constituting the aforementioned resin particles is 20°C or lower. The dissolution parameter of the resin constituting the resin particles is SP １ (cal / cm ３ ) １／２ , the dissolution parameter of the lubricant is SP ２ (cal / cm ３ ) １／２ In this case, 0.3 ≤ SP １ - SP ２ Satisfying ≤ 0.8, Image forming method.

2. The aforementioned resin particles include a (meth)acrylic resin. The image forming method according to claim 1.

3. The (meth)acrylic resin further has crosslinkable groups, At least one of the ink and the post-treatment liquid further comprises a crosslinking agent that reacts with the crosslinkable group. The image forming method according to claim 2.

4. The amount of crosslinking agent contained in the ink is greater than the amount of crosslinking agent contained in the post-treatment solution. The image forming method according to claim 3.

5. The lubricant includes a silicone resin. The image forming method according to claim 1 or 2.

6. The aforementioned silicone resin is a silicone acrylic copolymer. The image forming method according to claim 5.

7. The surface tension of the ink and the post-treatment liquid at 25°C is 36 to 50 mN / m, respectively. The image forming method according to claim 1.

8. When the surface temperature of the fabric is 40°C or lower, the time between applying the ink and starting to apply the post-treatment solution is 0.1 to 5 seconds. The image forming method according to claim 1.

9. The aforementioned fabric includes hydrophobic fibers and hydrophilic fibers. The image forming method according to claim 1.

10. This is an ink set for inkjet printing. An ink containing pigment and resin particles, It includes a post-treatment liquid containing a lubricant, The glass transition temperature of the resin constituting the aforementioned resin particles is 20°C or lower. When the solubility parameter of the resin constituting the resin particles is SP １ (cal / cm ３ ) １／２ and the solubility parameter of the lubricant is SP ２ (cal / cm ３ ), when 0.3 ≦ SP １／２ - SP １ - SP ２ ≦ 0.8 is satisfied, Ink set.

11. The aforementioned resin particles include (meth)acrylic resin, The lubricant comprises a silicone acrylic copolymer. The ink set according to claim 10.

Images