Pretreatment solution, pretreatment apparatus, and pretreatment method

Abstract

The present invention provides a pretreatment solution that can improve the wash fastness of images formed on fabrics. [Solution] The pretreatment liquid of the present disclosure is a pretreatment liquid applied to a fabric in a region including the ink discharge region before discharging the ink containing a pigment, and is characterized in that it contains a resin, and the storage modulus (G') of the dried upper layer component after centrifugation is 95 kPa or less at 25°C and 47 kPa or less at 160°C.

Description

[Technical Field]

[0001] This disclosure relates to a pretreatment solution, a pretreatment apparatus, and a pretreatment method. [Background technology]

[0002] Patent Document 1 discloses a pretreatment solution containing a resin that is applied before the step of applying an ink containing a pigment. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-63540 [Overview of the project] [Problems that the invention aims to solve]

[0004] Images formed by applying ink to fabric treated with a pretreatment solution, such as that disclosed in Patent Document 1, may peel off during washing, posing a problem with wash fastness.

[0005] Therefore, the present disclosure aims to provide a pretreatment solution, a pretreatment device, and a pretreatment method that can improve the wash fastness of images formed on fabrics. [Means for solving the problem]

[0006] To achieve the aforementioned objective, the pretreatment solution of the present disclosure is A pretreatment liquid applied to the fabric in the region including the ink discharge area before the pigment-containing ink is discharged, Contains resin, The dried upper layer component after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. It is characterized by the following:

[0007] The pretreatment device of the present disclosure is a pretreatment device that applies a pretreatment liquid applied to a fabric to an area including the ink ejection area before ejecting ink containing a pigment, including a pretreatment application unit that applies the pretreatment liquid to the fabric, where the pretreatment liquid is the dried product of the upper layer component after centrifugation, having a storage elastic modulus (G') at 25°C of 95 kPa or less, and having a storage elastic modulus (G') at 160°C of 47 kPa or less, characterized by this.

[0008] The pretreatment method of the present disclosure is a pretreatment method that applies a pretreatment liquid applied to a fabric to an area including the ink ejection area before ejecting ink containing a pigment, including a pretreatment step of applying the pretreatment liquid to the fabric, where the pretreatment liquid is the dried product of the upper layer component after centrifugation, having a storage elastic modulus (G') at 25°C of 95 kPa or less, and having a storage elastic modulus (G') at 160°C of 47 kPa or less, characterized by this.

Advantages of the Invention

[0009] According to the present disclosure, the washing fastness of an image formed on a fabric can be improved.

Brief Description of the Drawings

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of the pretreatment device of the present disclosure. [Figure 2] FIG. 2 is a flowchart showing an example of the steps in the pretreatment method of the present disclosure. [Figure 3A] FIG. 3A is a diagram showing an example of the application of the pretreatment liquid in the pretreatment method of the present disclosure. [Figure 3B]FIG. 3B is a diagram showing another application example of the pretreatment liquid in the pretreatment method of the present disclosure. [Figure 4] FIG. 4 is a graph showing the storage modulus (G') of the dried product of the upper layer component obtained by centrifuging the pretreatment liquids of the examples and comparative examples.

Mode for Carrying Out the Invention

[0011] Embodiments of the present disclosure will be described. Note that the present disclosure is not limited to the following embodiments. In the following figures, the same parts are denoted by the same reference numerals. Also, the descriptions of the respective embodiments can be mutually referred to unless otherwise specified. Furthermore, the configurations of the respective embodiments can be combined unless otherwise specified.

[0012] <Pretreatment Liquid> First, the pretreatment liquid of the present disclosure will be described. The pretreatment liquid of the present disclosure is a pretreatment liquid applied to a fabric in a region including the ink ejection region before ejecting ink containing a pigment, contains a resin, and the storage modulus (G') of the dried product of the upper layer component after centrifugation is 95 kPa or less at 25°C and 47 kPa or less at 160°C. Note that the region including the ink ejection region may be, for example, the entire region of the ink ejection region or a partial region of the ink ejection region.

[0013] Examples of the centrifugation method include the method described in the examples below. The upper layer component can also be referred to as, for example, the supernatant component or the separated product containing the resin described below.

[0014] Examples of the drying method of the upper layer component include the method described in the examples below.

[0015] The storage modulus (G') at 25°C may be, for example, 0.5 kPa or more, 1 kPa or more, 1.5 kPa or more, or 1.7 kPa or more, and may also be 85 kPa or less, 75 kPa or less, 50 kPa or less, 30 kPa or less, or 26 kPa or less. The inventors have found that when the storage modulus (G') at 25°C is 95 kPa or less, the resin described later has high flexibility, and therefore the image formed on the fabric tends to be resistant to cracking due to external forces. This finding is not shown in the prior art, including the aforementioned patent and non-patent documents, and is a finding independently discovered by the inventors.

[0016] The storage modulus (G') at 160°C may be, for example, 3 kPa or more, 3.5 kPa or more, or 3.9 kPa or more, and may also be 45 kPa or less, 30 kPa or less, 15 kPa or less, or 12 kPa or less. The inventors of this disclosure have found that when the storage modulus (G') at 160°C is 47 kPa or less, the resin described later becomes easier to soften when the pretreatment solution of this disclosure is heat-dried, so that it adheres well to the fabric and the image formed on the fabric tends to be less likely to peel off. This also leads to improved wash fastness. Furthermore, the inventors of this disclosure have found that the lower the storage modulus (G') at 160°C, the easier it is for the resin described later to form a uniform film on the fabric by heat drying, so that the color development of the image formed on the fabric may be improved. This finding is not shown in the prior art, including the aforementioned patent and non-patent documents, and is a finding independently discovered by the present inventors.

[0017] The storage modulus (G') can be measured, for example, using a rheometer. In this disclosure, unless otherwise specified, the term "storage modulus" refers to the storage modulus (G') in the shear mode. An example of a method for measuring the storage modulus (G') is the method described in the examples below.

[0018] The resin may, for example, be a resin included as a component of a resin emulsion. The resin emulsion is composed of, for example, the resin and a dispersion medium (for example, water). The resin is dispersed in the dispersion medium with a specific particle size, rather than being dissolved.

[0019] Examples of the aforementioned resins include acrylic acid resins, maleic acid ester resins, vinyl acetate resins, carbonate-type resins, polycarbonate-type resins, styrene-type resins, ethylene-type resins, polyethylene-type resins, propylene-type resins, polypropylene-type resins, urethane-type resins, polyurethane-type resins, and copolymer resins thereof. For example, styrene-type resins, acrylic acid-type resins, and copolymer resins thereof are preferred. The aforementioned resin may be one type of resin or two or more types of resins.

[0020] For example, a commercially available resin emulsion may be used. Examples of such commercially available products include "Movinyl® 6770", "Movinyl® 966A", "Movinyl® 7320", "Movinyl® 6963", and "Movinyl® 6960" from Japan Coating Resin Co., Ltd., "Vinibran® GV-6181" and "Vinibran® GV-1002" from Nisshin Chemical Industry Co., Ltd., and "Boncoat® SFC-55" and "Boncoat® SFC-571" from DIC Corporation.

[0021] With the total weight of all components contained in the pretreatment liquid being 100% by weight, the resin content is, for example, 0.1% to 30% by weight, 0.5% to 20% by weight, or 1% to 10% by weight.

[0022] The pretreatment solution may further contain, for example, at least one component selected from polyvalent metal salts, organic acids, organic solvents, amino acids, surfactants, and water.

[0023] Examples of the polyvalent metal salts include calcium salts, magnesium salts, and aluminum salts. Examples of the calcium salts include calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium lactate, calcium fumarate, calcium citrate, and their hydrates. Examples of the magnesium salts include magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, and their hydrates. Examples of the aluminum salts include aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, aluminum acetate, and their hydrates. One type of polyvalent metal salt may be used, or two or more types of polyvalent metal salts may be used. It is preferable that the polyvalent metal salts include at least one of calcium salts and magnesium salts, for example, from the viewpoint of suppressing discoloration of the fabric caused by pretreatment. It is also preferable that the polyvalent metal salts include calcium salts, for example, from the viewpoint of color development of the formed image and cost.

[0024] With the total amount of all components contained in the pretreatment solution being 100% by weight, the content of the polyvalent metal salt is, for example, 1% to 50% by weight, 5% to 30% by weight, or 10% to 25% by weight.

[0025] Examples of the aforementioned organic acids include saturated fatty acids such as formic acid, acetic acid, propionic acid, butyric acid, and valeric acid; hydroxy acids such as lactic acid, malic acid, and citric acid; aromatic carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, terephthalic acid, salicylic acid, and gallic acid; dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, and fumaric acid; uronic acids such as glucuronic acid, galacturonic acid, and iduronic acid; ascorbic acid; and others, but are not particularly limited. The aforementioned organic acid may also be a salt in which the cation is not a metal ion (for example, an ammonium salt or an amine salt).

[0026] The organic solvent and the amino acid may, for example, have a molecular weight of 90 or more, 100 or more, or 105 or more, or 170 or more, 180 or more, 190 or more, or 200 or more. The organic solvent and the amino acid may, for example, have a molecular weight of 120 or less, or 500 or less, or 400 or less. In the case of a high molecular weight organic solvent, the molecular weight may be interpreted as, for example, the number average molecular weight. When the molecular weight of the organic solvent and the amino acid is 100 or more, the boiling point tends to be higher, which can reduce the generation of smoke (vapor) originating from the evaporation of the organic solvent and the amino acid when drying the pretreatment solution. By reducing the generation of smoke, for example, the visibility of the work environment can be improved, which can improve the workability of the pretreatment application work. In this disclosure, the organic solvent and the amino acid function, for example, as a wetting agent.

[0027] Examples of the organic solvent include glycol-based solvents and glycerol-based solvents. Examples of the glycol-based solvent include ethylene glycol, diethylene glycol, polyalkylene glycol, 1,3-propanediol, and derivatives thereof. The polyalkylene glycol may be, for example, a polyalkylene glycol with a molecular weight (number average molecular weight) of 200, 300, or 400. Examples of the glycerol-based solvent include glycerin, diglycerin, and derivatives thereof. One type of organic solvent may be used, or two or more types of organic solvents may be used.

[0028] Examples of the polyalkylene glycol include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyoxyethylene polyoxypropylene glycol. Examples of derivatives of the polyalkylene glycol include diglycerin, polyglycerin, polyoxyethylene glycerin, polyethylene glycol monolauryl ether, polyethylene glycol monododecyl ether, and polyethylene glycol monomethyl ether.

[0029] Examples of the aforementioned amino acids include betaine. Examples of the aforementioned betaine include trimethylglycine, carnitine, γ-butyrobetaine, taurobetaine, lysine betaine, and alanine betaine. Examples of amino acids other than betaine include glycine, alanine, aspartic acid, glutamic acid, lysine, arginine, and histidine.

[0030] Taking the total weight of all components contained in the pretreatment liquid as 100% by weight, the content of the organic solvent and the amino acid may be, for example, 15% by weight or more, 25% by weight or less, or 20% by weight or less. From the viewpoint of washing fastness after image formation, the content of the organic solvent and the amino acid is preferably, for example, 15% by weight or more. Furthermore, from the viewpoint of drying efficiency, the content of the organic solvent and the amino acid is preferably, for example, 20% by weight or less.

[0031] Furthermore, if the pretreatment solution contains at least one of an organic solvent and an amino acid, and the organic solvent is at least one of an organic solvent with a molecular weight of 120 or less and an organic solvent with a molecular weight of 170 or more, and the amino acid is at least one of an amino acid with a molecular weight of 120 or less and an amino acid with a molecular weight of 170 or more, then, with the total weight of all components contained in the pretreatment solution being 100% by weight, the content of at least one of the organic solvent and the amino acid may be, for example, 15% by weight or more. By having a content of 15% by weight or more, for example, the abrasion resistance of the pretreated portion may be improved.

[0032] The reason for the improved abrasion resistance can be attributed to, for example, the following: When the pretreatment liquid of this disclosure is dried, the resin components in the resin emulsion contained in the pretreatment liquid melt due to heat and form a film. At this time, the film is formed while incorporating the organic solvent and amino acids contained in the pretreatment liquid. Films formed with the organic solvent and amino acids incorporated tend to have reduced film strength and are therefore more susceptible to damage from abrasion. This can be a cause of abrasion marks. On the other hand, the phenomenon of the organic solvent and amino acids being incorporated means that the organic solvent and amino acids penetrate between the molecular structures of the resin. Therefore, organic solvents and amino acids with lower molecular weights tend to penetrate between the molecular structures more easily. Furthermore, the organic solvents and amino acids move to the upper surface of the fabric without penetrating between the molecular structures due to the evaporation of water accompanying the drying of the pretreatment liquid. This movement tends to occur more easily with lower molecular weights, so abrasion marks are less likely to occur when the molecular weight of the organic solvent or amino acid is 120 or less. Furthermore, when the molecular weight is 170 or more, the large molecular size of the organic solvent and the amino acid makes it difficult for them to penetrate between the molecular structures, thus reducing the likelihood of scratches. However, the above principle is merely a hypothesis, and this disclosure is not limited to the above principle.

[0033] The pretreatment solution of the present disclosure may contain, for example, other organic solvents. Examples of such other organic solvents include other polyhydric alcohols, other polyhydric alcohol derivatives, sugar alcohols, alcohols, amides, ketones, keto alcohols, ethers, nitrogen-containing solvents, sulfur-containing solvents, propylene carbonate, ethylene carbonate, 1,3-dimethyl-2-imidazolidinone, and the like.

[0034] Examples of other polyhydric alcohols include propylene glycol, butylene glycol, hexylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, trimethylolpropane, 1,5-pentanediol, and 1,2,6-hexanetriol. Examples of the aforementioned other polyhydric alcohol derivatives include ethylene glycol methyl ether, ethylene glycol ethyl ether, ethylene glycol-n-propyl ether, ethylene glycol-n-butyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol-n-propyl ether, diethylene glycol-n-butyl ether, diethylene glycol-n-hexyl ether, triethylene glycol methyl ether, triethylene glycol ethyl ether, triethylene glycol-n-propyl ether, triethylene glycol-n-butyl ether, propylene glycol methyl ether, propylene glycol ethyl ether, propylene glycol-n-propyl ether, propylene glycol-n-butyl ether, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol-n-propyl ether, dipropylene glycol-n-butyl ether, tripropylene glycol methyl ether, tripropylene glycol ethyl ether, tripropylene glycol-n-propyl ether, and tripropylene glycol-n-butyl ether. Examples of the aforementioned sugar alcohols include sorbitol, mannitol, iditol, talitol, dulcitol, arodulcitol, xylitol, ribitol, arabitol, erythritol, treitol, isomalt, lactitol, boremitol, verseitol, and pentaerythritol. Examples of the aforementioned alcohols include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, and benzyl alcohol.Examples of the amide include dimethylformamide and dimethylacetamide. Examples of the ketone include acetone. Examples of the keto alcohol include diacetone alcohol. Examples of the ether include tetrahydrofuran and dioxane. Examples of the nitrogen-containing solvent include pyrrolidone, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, and triethanolamine. Examples of the sulfur-containing solvent include thiodiethanol, thiodiglycol, thiodiglycerol, sulfolane, and dimethyl sulfoxide.

[0035] Examples of the surfactant include nonionic surfactants. Examples of the nonionic surfactant include acetylene glycol-based surfactants. Commercially available nonionic surfactants may also be used. Examples of commercially available products include "Orphin® E1004", "Orphin® E1006", "Orphin® E1010", "Orphin® E1020", "Orphin® EXP4001", "Orphin® EXP4200", "Orphin® EXP4123", "Orphin® EXP4300", "Orphin® PD-001", "Orphin® PD-002W", "Orphin® PD-005", "Surfinol® 420", "Surfinol® 440", "Surfinol® 465", and "Surfinol® 485", all manufactured by Nisshin Chemical Industry Co., Ltd.

[0036] The surfactant may further include surfactants other than nonionic surfactants (for example, anionic surfactants, cationic surfactants, amphoteric surfactants, etc.).

[0037] With the total weight of all components contained in the pretreatment solution being 100% by weight, the content of the surfactant may be, for example, 0.01% by weight or more, 0.02% by weight or more, 0.03% by weight or more, or 0.04% by weight or more, or 2% by weight or less, 1.5% by weight or less, 1% by weight or less, 0.8% by weight or less, 0.5% by weight or less, 0.3% by weight or less, or 0.1% by weight or less.

[0038] Examples of the aforementioned water include ion-exchanged water and pure water.

[0039] With the total weight of all components in the pretreatment solution being 100% by weight, the water content is, for example, 10% to 90% by weight, or 20% to 80% by weight. The water content may, for example, be the remainder of the other components.

[0040] The pretreatment solution of the present disclosure may further contain additives such as crosslinking agents, pH adjusters, viscosity adjusters, preservatives, and fungicides, as needed.

[0041] Examples of pigments contained in the ink include carbon black, inorganic pigments, and organic pigments. Examples of carbon black include furnace black, lamp black, acetylene black, and channel black. Examples of inorganic pigments include titanium dioxide, iron oxide-based inorganic pigments, and carbon black-based inorganic pigments. Examples of organic pigments include azo pigments such as azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments; polycyclic pigments such as phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments; dye lake pigments such as basic dye-type lake pigments and acid dye-type lake pigments; nitro pigments; nitroso pigments; aniline black daylight fluorescent pigments; and others. In addition, other pigments can be used as long as they are dispersible in the aqueous phase. Specific examples of these pigments include, for example, CI Pigment White 1, 4, 5, 6, 7, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, and 28; CI Pigment Black 1, 6, and 7; CI Pigment Yellow 1, 2, 3, 12, 13, 14, 15, 16, 17, 55, 74, 78, 150, 151, 154, 180, 185, and 194; CI Pigment Orange 31 and 43; CI Pigment Red 2, 3, 5, 6, 7, 12, 15, 16, 48, and 48: Examples include 1, 53:1, 57, 57:1, 112, 122, 123, 139, 144, 146, 149, 150, 166, 168, 175, 176, 177, 178, 184, 185, 190, 202, 209, 221, 222, 224 and 238; CI Pigment Violet 19 and 196; CI Pigment Blue 1, 2, 3, 15, 15:1, 15:2, 15:3, 15:4, 16, 22 and 60; CI Pigment Green 7 and 36; and solid solutions of these pigments.

[0042] The pigment may be dispersed in a solvent by a resin dispersant (also called a resin-dispersed pigment). The resin dispersant may be, for example, a general polymer dispersant (also called a pigment dispersion resin or resin dispersant, etc.), or may be prepared in-house. In addition, in the adhesive solution of this disclosure, the pigment may be encapsulated by a polymer. The resin dispersant may be, for example, one containing at least one of methacrylic acid and acrylic acid as a monomer, and commercially available products may be used. The resin dispersant may be, for example, a hydrophobic monomer such as styrene, styrene derivatives, vinylnaphthalene, vinylnaphthalene derivatives, or aliphatic alcohol esters of α,β-ethylenically unsaturated carboxylic acids, or a block copolymer, graft copolymer, or random copolymer or a salt thereof, consisting of two or more monomers selected from the group consisting of acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid derivatives, fumaric acid, or fumaric acid derivatives. Examples of the aforementioned commercially available products include "Johncryl® 611", "Johncryl® 60", "Johncryl® 586", "Johncryl® 687", "Johncryl® 63", and "Johncryl® HPD296" manufactured by Johnson Polymer Co., Ltd.; "Disperbyk190" and "Disperbyk191" manufactured by Bic Chemie; and "Solspers 20000" and "Solspers 27000" manufactured by Zeneca.

[0043] A method for dispersing the pigment using the aforementioned pigment dispersion resin includes, for example, a method of dispersing the pigment using a dispersion apparatus. The dispersion apparatus used for dispersing the pigment is not particularly limited as long as it is a general-purpose dispersion machine, but examples include ball mills, roll mills, sand mills (e.g., high-speed type), etc.

[0044] The pigment may be a self-dispersing pigment. The self-dispersing pigment is such that, for example, at least one of a hydrophilic functional group such as a carbonyl group, hydroxyl group, carboxylic acid group, sulfonic acid group, or phosphate group, and salts thereof, is introduced into the pigment particles by chemical bonding, either directly or via other groups, so that it can be dispersed in water without the use of a dispersant. The self-dispersing pigment can be one in which the pigment has been treated by the method described in, for example, Japanese Patent Publication No. 8-3498, Japanese Patent Publication No. 2000-513396, Japanese Patent Publication No. 2008-524400, Japanese Patent Publication No. 2009-515007, Japanese Patent Publication No. 2011-515535, etc. The raw material for the self-dispersing pigment can be either an inorganic pigment or an organic pigment. Examples of pigments suitable for the above treatment include carbon black such as "MA8" and "MA100" manufactured by Mitsubishi Chemical Corporation. The self-dispersing pigment can be a commercially available product, for example. Examples of the aforementioned commercially available products include "CAB-O-JET(registered trademark) 200", "CAB-O-JET(registered trademark) 250C", "CAB-O-JET(registered trademark) 260M", "CAB-O-JET(registered trademark) 270Y", "CAB-O-JET(registered trademark) 300", "CAB-O-JET(registered trademark) 400", "CAB-O-JET(registered trademark) 450C", "CAB-O-JET(registered trademark) 465M", and "CAB-O-JET(registered trademark) 470Y" manufactured by Cabot Corporation; "BONJET(registered trademark) BLACK CW-2" and "BONJET(registered trademark) BLACK CW-3" manufactured by Orient Chemical Industry Co., Ltd.; and "LIOJET(registered trademark) WD BLACK 002C" manufactured by Toyo Ink Manufacturing Co., Ltd.

[0045] The aforementioned pigment may consist of one type of pigment or two or more types of pigments.

[0046] Examples of the fabric include knitted fabrics and woven fabrics. The material of the fabric may be natural fibers or synthetic fibers. Examples of natural fibers include cotton and silk. Examples of synthetic fibers include polyester, acrylic, rayon, urethane, and nylon. The material of the fabric may be a blend spun by mixing multiple types of the fibers, such as cotton / polyester = 50% / 50%.

[0047] <Pretreatment device> Next, a pre-processing apparatus of the present disclosure will be described. Figure 1 shows an example of the configuration of the pre-processing apparatus of the present disclosure. As shown in Figure 1, the pre-processing apparatus 10 of the present disclosure is a pre-processing apparatus that applies a pre-treatment liquid to the fabric to a region including the ink discharge region before the ink containing the pigment is discharged, and is characterized by including a pre-treatment application unit 11 that applies the pre-treatment liquid to the fabric.

[0048] Examples of pre-treatment units 11 include liquid dispensing means such as a liquid dispensing head, sprayers, stamps, brushes, rollers, etc.

[0049] The pretreatment solution in the pretreatment apparatus 10 of this disclosure is the same as the pretreatment solution described above, and the explanation therein can be applied.

[0050] Furthermore, the preprocessing apparatus of this disclosure may further include, for example, a heat treatment section. The heat treatment section may be, for example, a commercially available heat press and / or oven.

[0051] <Pre-treatment method> Next, a pretreatment method of the present disclosure will be described. Figure 2 is a flowchart showing an example of the steps in the pretreatment method of the present disclosure. The pretreatment method of the present disclosure is a pretreatment method that applies a pretreatment liquid to the fabric to a region including the ink discharge region before the ink containing the pigment is discharged, and includes a pretreatment application step.

[0052] The pretreatment application step (S11) involves applying the pretreatment liquid to the fabric. The pretreatment application step may be performed, for example, by the pretreatment application unit 11 of the pretreatment apparatus 10 of the present disclosure. In the pretreatment application step, the application of the pretreatment liquid can be carried out by methods such as inkjet, spray, stamp application, brush application, roller application, padding, etc.

[0053] In the pretreatment application step, the pretreatment liquid may be applied to the entire image-forming surface of the fabric or to a part of it. When applied to a part, for example, the pretreatment liquid application area may be an area that is roughly the same as the ink discharge area on the image-forming surface of the fabric. When applied to a part, the size of the pretreatment liquid application area should be larger than the printed area. Figure 3A is a diagram showing an example of the application of the pretreatment liquid in the pretreatment method of the present disclosure. For example, as shown in Figure 3A, when printing the character (X) on the fabric (T-shirt in this example) 100, it is preferable to apply the pretreatment liquid so as to form a pretreatment liquid application area 110 with a line width larger than the line width of the character. Figure 3B is a diagram showing another example of the application of the pretreatment liquid in the pretreatment method of the present disclosure. As shown in Figure 3B, when printing a design on the fabric (T-shirt) 100, it is preferable to apply the pretreatment liquid so as to form a pretreatment liquid application area 120 larger than the design.

[0054] Furthermore, the pretreatment method of this disclosure may include, for example, a heat treatment step after the pretreatment liquid application step. The heat treatment step may be carried out by, for example, a heat press and an oven. The heat press and the oven may be commercially available products, for example. The heat treatment temperature in the heat treatment step may differ depending on whether the heat treatment is carried out by the heat press or the oven. The heat treatment temperature when using the heat press is, for example, 140°C to 200°C. The heat treatment temperature when using the oven is, for example, 140°C to 180°C. Furthermore, the pretreatment method of this disclosure can be carried out by, for example, the pretreatment apparatus 10 described above. [Examples]

[0055] Next, embodiments of this disclosure will be described together with comparative examples. However, this disclosure is not limited to or restricted by the embodiments and comparative examples described below.

[0056] [Examples 1-8, Comparative Examples 1-3] The pretreatment solutions for Examples 1-8 and Comparative Examples 1-2, shown in Table 2, were obtained by stirring and mixing each component in the pretreatment solution composition (Table 2). Specifically, the polyvalent metal salts and water shown in Table 2 were pre-mixed. Next, the surfactant, organic solvent or amino acid, resin emulsion, and preservative were added in order to obtain the pretreatment solutions shown in Table 2. The pretreatment solution for Comparative Example 3 is a commercially available pretreatment solution and, in addition to the components listed in Table 1, contains an acrylic resin (content unknown) as a resin emulsion. Note that the amounts of each component in Table 2 all represent the amount of active ingredient.

[0057] Using the pretreatment solutions from Examples 1-8 and Comparative Examples 1-3, images were formed on a black T-shirt (manufactured by GILDAN, product name: GILDAN® Ultra cotton, material: 100% cotton) by the following process.

[0058] (Pre-treatment process) The pretreatment solution prepared as shown in Table 2 was diluted with water until its volume was three times the original volume. The diluted pretreatment solution was applied to the image-forming surface of the T-shirt using an automated pretreatment coating device (PRINTSYSTEM, product name: THE CUBE) (24 mg / cm²). 2 ).

[0059] (Heat treatment process (1)) After the aforementioned pretreatment step, the pretreatment solution was applied to the pretreatment area of ​​the T-shirt, and then the pretreatment was fixed using a heat press (STAHLS' Hotronix, product name: AIR FUSION IQ®). The heat treatment was performed for 35 seconds at a set temperature of 185°C and a set pressure of 31 psi.

[0060] (Image printing process) Images were printed onto T-shirts treated with a pre-treatment solution by ejecting white ink (referred to as "W ink" in Table 2) using an inkjet printer (Brother Industries, Ltd., product name: GTX® pro). White ink (Brother Industries, Ltd., product name: GCX-4W) was used as the ink. The amount of white ink used was as shown in Table 2.

[0061] (Heat treatment process (2)) After the image printing process, the ink was heat-fixed to the printed area of ​​the T-shirt using a dryer (ADELCO, product name: Drawer Drying Cabinet, model number: DDC-3A) set to 160°C. The heating time for the heat fixing was 3.5 minutes.

[0062] In this embodiment, evaluation samples were created by each step, but this is merely an example, and the method of creation is not limited to the above. For example, the order of each step may be changed as appropriate. Changing the method of creating the evaluation samples will not change the evaluation results described later.

[0063] For the pretreatment solutions of Examples 1 to 8 and Comparative Examples 1 to 3, (a) storage modulus (G') evaluation, (b) color development evaluation, (c) wash fastness evaluation, (d) smoke generation evaluation, and (e) abrasion resistance evaluation were performed using the following methods.

[0064] (a) Evaluation of the storage modulus (G') As described above, the prepared pretreatment solution was transferred to a centrifuge tube and centrifuged at 12,000 rpm using a centrifuge (manufactured by Kubota Shoji Co., Ltd., product name: KUBOTA3200). Centrifugation was continued until the volume ratio of the upper layer component (supernatant) to the lower layer component (precipitation) was approximately 1:1. After centrifugation, the upper layer component was transferred to a container of choice and dried at 80°C for 3 hours using a small environmental testing machine (manufactured by ESPEC Corporation, model: SH-241) to obtain a dried product. Note that the upper layer component after centrifugation contains lighter components than the lower layer component. The obtained dried product was punched out with a φ8 mm leather punch to serve as an evaluation sample. The storage modulus (G') of the obtained dried product at 25°C and 160°C was measured using a rheometer (manufactured by TA Instruments, product name: Discovery HR 20). The measurement conditions for the storage modulus (G') are as follows. • Geometry: φ8mm parallel plate • Geometry gap: 100-1000 μm • Gap adjustment during measurement: None ·Measurement frequency: 1Hz • Measurement strain: 1% • Axial force adjustment: None

[0065] Here, the storage modulus (G') measured after holding the obtained dried material at 25°C for 5 minutes was defined as the "storage modulus (G') at 25°C". Furthermore, the storage modulus (G') measured after holding the obtained dried material at 25°C for 5 minutes, then raising the temperature to 160°C at a rate of 5°C / min, and then holding it at 160°C for 5 minutes was defined as the "storage modulus (G') at 160°C". In this embodiment, centrifugation was performed until the volume ratio of the upper layer component (supernatant) and the lower layer component (precipitation) was approximately 1:1. However, this is not limited to this method; for example, the upper layer component separated to any volume ratio may be used as an evaluation sample for the storage modulus (G').

[0066] As will be discussed later, the result that Examples 1-8 exhibited better wash fastness than Comparative Examples 1-3 means that it is important that the storage modulus (G') of the dried upper layer component after centrifugation of the pretreatment solution is within a specific range at room temperature and also within a specific range at high temperatures. This indicates that the storage modulus (G') at high temperatures is not limited to a specific temperature. Figure 4 and Table 1 show the storage modulus (G') at each temperature when the dried upper layer component obtained by centrifugation of the pretreatment solutions of Examples 1-8 and Comparative Examples 1-3 was heated from 130°C to 160°C under the aforementioned heating conditions. From the results in Figure 4 and Table 1, it has been confirmed that the numerical range of the storage modulus (G') in this disclosure may be set based on the storage modulus (G') at each temperature from 130°C to 160°C. In other words, although the storage modulus (G') at 160°C is used as an example in this disclosure, it can be seen that the storage modulus (G') at any temperature between 130°C and 160°C will also satisfy the numerical range of the storage modulus (G') in this disclosure. Therefore, even if a temperature below 160°C is added to the pretreatment solution during the heat treatment process, if the storage modulus (G') at 160°C is within the numerical range of this disclosure, it is understood to be included in the technical scope of this disclosure.

[0067] [Table 1]

[0068] (b) Color development evaluation Using the pretreatment solutions from Examples 1-8 and Comparative Examples 1-3, evaluation samples were obtained by following the procedure from the "pretreatment application step" to the "heat fixing step (2)" described above. The L of the printed area of ​​the T-shirt on which the image of the evaluation sample was formed. * Value, CIE1976L * a * b * Measurements were taken using a color space scale colorimeter (X-Rite PANTONE, product name: X-Rite eXact).

[0069] (c) Wash fastness evaluation The T-shirt with the image formed was washed in a washing and drying machine (manufactured by MAYTAG, product number: MWI74140JB2) using a general household laundry detergent under the conditions of the COTTON mode and a water temperature of 60°C, and then dried using a clothes dryer (manufactured by Panasonic Corporation, product number: NH-D603) in the standard mode and the heater "strong" mode. The lightness (L1 * and L2 * ) of the ink coating (image) before and after washing was measured using a CIE1976L * a * b * color space scale colorimeter (manufactured by X-Rite PANTONE, product name: X-Rite eXact). Based on the measured lightness, ΔL * was calculated according to the following formula (1), and this was used as an index of washing fastness. Note that the higher the washing fastness, the smaller the value of ΔL * . ΔL * =|L2 * -L1 * | (1) L1 * : Lightness of the ink coating before washing L2 * : Lightness of the ink coating after washing

[0070] (d) Smoke generation evaluation The pretreatment liquid prepared as described above was spray-coated onto the fabric (24 mg / cm 2 ). Then, the fabric to which the pretreatment liquid was applied was heated at 200°C using a hot plate (manufactured by Seieiido Co., Ltd., product number: PMC-720). The presence or absence of smoke generation from the area where the pretreatment liquid was applied was observed between 2 minutes and 2.5 minutes after heating, and evaluation was performed based on the following evaluation criteria.

[0071] Smoke generation evaluation criteria 〇: No smoke was generated. ×: Smoke was generated. Furthermore, "smoke has been produced" means that smoke is produced multiple times during the heating period between 2 and 2.5 minutes after heating, with each occurrence occurring at an interval of less than 3 seconds.

[0072] (e) Scratch resistance evaluation For the T-shirts after the aforementioned heat treatment process (1), the areas to which the pretreatment solution had been applied were rubbed with a metal plate at an angle of 45° ± 15° relative to the surface of the T-shirt, while applying a load of 0.5 kgf ± 0.1 kgf. The abrasion resistance was evaluated based on the following evaluation criteria. The metal plate used was 15 mm wide and 0.7 mm thick.

[0073] Scratch resistance evaluation criteria ○: No abrasion marks occurred. ×: Scratch marks occurred.

[0074] Table 2 shows the composition and evaluation results of the pretreatment solutions for Examples 1-8 and Comparative Examples 1-3.

[0075] [Table 2]

[0076] As shown in Table 2, Examples 1 to 8 exhibited good wash fastness under both conditions of high and low ink application. Specifically, pretreatment solutions in which the storage modulus (G') of the dried upper layer component after centrifugation was 95 kPa or less at 25°C and 47 kPa or less at 160°C exhibited good wash fastness in all examples. Furthermore, in Examples 1 to 6 and 8, the generation of smoke was reduced compared to other examples due to the molecular weight of the organic solvent and the amino acid being 100 or more. Moreover, in Examples 3 to 6 and 8, the molecular weight of the organic solvent and the amino acid was 120 or less, or 170 or more, and by including at least 15% by weight or more of the organic solvent and the amino acid, with the total of all components in the pretreatment solution being 100% by weight, the abrasion resistance was better compared to other examples. In addition, in Examples 4 and 5, the storage modulus (G') of the dried upper layer component after centrifugation was 95 kPa or less at 25°C and 47 kPa or less at 160°C, resulting in better color development of the image formed on the fabric compared to the other examples. On the other hand, Comparative Examples 1 to 3 showed poor wash fastness under at least one of the conditions of high and low ink application.

[0077] This disclosure may also be described in part or in whole as follows, but is not limited to the following: (Note 1) A pretreatment liquid applied to the fabric in the region including the ink discharge area before the pigment-containing ink is discharged, Contains resin, The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A pretreatment solution characterized by the following features. (Note 2) It contains at least one of an organic solvent and an amino acid, The molecular weights of the organic solvent and the amino acid are 100 or more. The pretreatment solution described in Appendix 1. (Note 3) It contains at least one of an organic solvent and an amino acid, The organic solvent is at least one of an organic solvent with a molecular weight of 120 or less and an organic solvent with a molecular weight of 170 or more. The amino acid is at least one of an amino acid with a molecular weight of 120 or less and an amino acid with a molecular weight of 170 or more. Assuming the total amount of all components contained in the aforementioned pretreatment solution is 100% by weight, The organic solvent and the amino acid are contained in an amount of 15% by weight or more. The pretreatment solution described in Appendix 1. (Note 4) The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 26 kPa or less. The storage modulus (G') at 160°C is 12 kPa or less. The pretreatment solution described in Appendix 1. (Note 5) A pretreatment apparatus for applying a pretreatment liquid to a fabric to a region including the ink discharge region before discharging the ink containing the pigment, The system includes a pretreatment application unit that applies the pretreatment liquid to the fabric, The aforementioned pretreatment liquid is The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A preprocessing apparatus characterized by the following: (Note 6) A pretreatment method comprising applying a pretreatment liquid to a fabric in a region including the ink discharge area before dispensing the ink containing the pigment, The process includes a pretreatment step of applying the pretreatment solution to the fabric, The aforementioned pretreatment liquid is The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A pretreatment method characterized by the following: [Industrial applicability]

[0078] As described above, the pretreatment solution of the present disclosure can improve the wash fastness of images formed on fabrics. The applications of the pretreatment solution of the present disclosure are not particularly limited and can be widely applied to pretreatment of various fabrics before image formation. [Explanation of symbols]

[0079] 10 Pre-treatment device 11 Pre-treatment application unit

Claims

1. A pretreatment liquid applied to the fabric in the region including the ink discharge area before the pigment-containing ink is discharged, Contains resin, The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A pretreatment solution characterized by the following features.

2. It contains at least one of an organic solvent and an amino acid, The molecular weights of the organic solvent and the amino acid are 100 or more. The pretreatment solution according to claim 1.

3. It contains at least one of an organic solvent and an amino acid, The organic solvent is at least one of an organic solvent with a molecular weight of 120 or less and an organic solvent with a molecular weight of 170 or more. The amino acid is at least one of an amino acid with a molecular weight of 120 or less and an amino acid with a molecular weight of 170 or more. Assuming the total amount of all components contained in the aforementioned pretreatment solution is 100% by weight, The organic solvent and the amino acid are contained in an amount of 15% by weight or more. The pretreatment solution according to claim 1.

4. The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 26 kPa or less. The storage modulus (G') at 160°C is 12 kPa or less. The pretreatment solution according to claim 1.

5. A pretreatment apparatus for applying a pretreatment liquid to a fabric to a region including the ink discharge region before discharging the ink containing the pigment, The system includes a pretreatment application unit that applies the pretreatment liquid to the fabric, The aforementioned pretreatment liquid is The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A pretreatment apparatus characterized by the following:

6. A pretreatment method comprising applying a pretreatment liquid to a fabric in a region including the ink discharge area before dispensing the ink containing the pigment, The process includes a pretreatment step of applying the pretreatment solution to the fabric, The aforementioned pretreatment liquid is The dried upper layer of components after centrifugation, The storage modulus (G') at 25°C is 95 kPa or less. The storage modulus (G') at 160°C is 47 kPa or less. A pretreatment method characterized by the following:

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