Pretreatment solution and image forming method

Abstract

To provide a pretreatment liquid that can form an image having high coloring density and fastness to rubbing even on a fabric containing hydrophilic fiber such as natural fiber.SOLUTION: The pretreatment liquid of the present invention is a pretreatment liquid for fabric used for transfer textile printing, and the pretreatment liquid contains a solvent having an organic / inorganic value (I / O value) of 1.0 to 3.0, and has a surface tension at 25°C of less than 38 mN / m.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a pretreatment liquid and an image forming method.

Background Art

[0002] As a printing method using ink containing a dye, a method of transferring and dyeing an ink layer containing a disperse dye formed on a transfer medium (sublimation transfer printing method) is known.

[0003] Since disperse dyes generally exhibit hydrophobicity, they are likely to adhere and be dyed to fabrics containing hydrophobic fibers such as polyester fibers. However, for fabrics containing hydrophilic fibers such as natural fibers, due to the large polarity difference between the disperse dye and the fabric, the penetration and fixing properties of the disperse dye are not sufficient, and it is difficult to dye. Therefore, studies have been made to make it easier to dye disperse dyes on fabrics containing hydrophilic fibers such as natural fibers.

[0004] As such a method, a transfer printing method is known in which a fabric is swollen with a swelling agent, then transfer printed, and a synthetic resin liquid is applied to the surface of the dyed fabric (for example, Patent Document 1). As the swelling agent, an aqueous solution containing polyhydric alcohols such as polypropylene glycol (I / O value: 3.3) is used.

[0005] Also, a transfer printing method is known in which a fabric is pretreated with a pretreatment liquid containing a swelling agent and a water repellent, then transfer printed, and the dyed fabric is washed to remove the swelling agent (for example, Patent Document 2). As the swelling agent, polyhydric alcohols such as polypropylene glycol (I / O value: 3.3) are used.

[0006] Also, a transfer printing method is known in which a fabric is pretreated with a swelling agent, then transfer printed, and post-treated with a treating agent containing a crosslinking agent and a catalyst (for example, Patent Document 3). As the swelling agent, a mixture of triethylene glycol (I / O value: 2.0) and ethylene glycol monoacetate (I / O value: 1.75) is used.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Application Publication No. 7-216763 [Patent Document 2] Japanese Patent Publication No. 2021-42514 [Patent Document 3] Japanese Patent Application Publication No. 49-30686 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, even when applying the methods described in Patent Documents 1 to 3 to fabrics containing hydrophilic fibers such as natural fibers, it was not possible to obtain printed materials with sufficient color density and friction fastness.

[0009] Specifically, the solvents contained in the pretreatment solutions of Patent Documents 1 and 2 have low affinity for disperse dyes, making it difficult to obtain friction fastness. The pretreatment solution of Patent Document 3 has high surface tension and does not easily penetrate into the interior of the fabric fibers. Therefore, the disperse dye does not easily penetrate into the interior of the pretreated fabric fibers, making it difficult to obtain both color intensity and friction fastness.

[0010] The present invention has been made in view of the above problems, and aims to provide a pretreatment solution and an image forming method that can form images with high color density and friction fastness even on fabrics containing hydrophilic fibers such as natural fibers. [Means for solving the problem]

[0011] The above problem can be solved by the following configuration.

[0012] The pretreatment solution of the present invention is a pretreatment solution for fabrics used in transfer printing, and contains a solvent having an organic / inorganic value (I / O value) of 1.0 to 3.0, and has a surface tension of less than 38 mN / m at 25°C.

[0013] The image forming method of the present invention includes the steps of applying the pretreatment solution of the present invention to a fabric containing natural fibers or synthetic cellulose fibers, and transferring an ink layer containing a disperse dye onto the fabric to which the pretreatment solution has been applied. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a pretreatment solution and an image forming method that can form images with high color density and friction fastness even on fabrics containing hydrophilic fibers such as natural fibers. [Modes for carrying out the invention]

[0015] The inventors have discovered that by treating fabrics containing hydrophilic fibers such as natural fibers with a pretreatment solution containing a solvent with an I / O value of 1.0 to 3.0 and a surface tension of less than 38 mN / m, images with high color density and friction fastness can be formed.

[0016] Although the mechanism is not clear, it is speculated that: Solvents with an I / O value of 1.0 to 3.0 readily attract hydrophilic fibers such as natural fibers with an I / O value of around 3.0, thus easily causing the fibers to swell. Furthermore, solvents with an I / O value of 1.0 to 3.0 readily attract disperse dyes with an I / O value of around 1.0, and can therefore function as carriers for disperse dyes in fabrics treated with a pretreatment solution containing these solvents. Due to these effects, disperse dyes can more easily penetrate into the fibers of the fabric, thereby increasing the color intensity. In addition, the amount of disperse dye remaining on the surface of the fibers without penetrating the interior can be reduced, thus improving friction fastness.

[0017] Furthermore, by keeping the surface tension of the pretreatment solution below a certain level, the pretreatment solution can penetrate more easily into the fibers, and the disperse dye can penetrate more easily into the fibers. As a result, the amount of disperse dye remaining on the fiber surface can be further reduced, thereby further improving color intensity and friction fastness.

[0018] In particular, the color development property is more likely to increase as the swelling degree of the fiber is higher (the closer the I / O value is to 3.0) and the permeability of the pretreatment liquid is higher (the lower the surface tension is); the rubbing fastness is more likely to increase as the carrier property of the disperse dye in the pretreatment liquid is higher (the closer the I / O value is to 1.0) and the permeability is higher (the lower the surface tension is). Hereinafter, the composition of the pretreatment liquid of the present invention will be described in detail.

[0019] 1. Pretreatment liquid The pretreatment liquid contains a solvent having an I / O value of 1.0 to 3.0.

[0020] 1-1. Solvent In the solvent having an I / O value of 1.0 to 3.0, the "I / O value" is the ratio of the inorganic value (I) to the organic value (O) (inorganic value / organic value), and is one of the indexes indicating the magnitude of polarity. The closer the I / O value is to 0, the more non-polar (hydrophobic) it indicates, and the larger the value, the more polar (hydrophilic) it indicates.

[0021] As described above, the solvent having an I / O value of 1.0 to 3.0 is likely to affinity with natural fibers or synthetic cellulose fibers (I / O value: about 3.0) constituting the fabric, so it is easy to swell these fibers. In the fabric treated with the pretreatment liquid containing such a solvent, the disperse dye is likely to enter the inside of the fiber. On the other hand, the solvent having an I / O value of 1.0 to 3.0 is also likely to affinity with the disperse dye (I / O value: about 1.0), so it can function as a carrier of the disperse dye during transfer printing. Thereby, it is possible to easily move the disperse dye from the surface to the inside of the fiber. Thereby, an image formation product having a high color density and excellent rubbing fastness can be obtained. From the same viewpoint, the I / O value of the above solvent is more preferably 1.0 to 2.0, and even more preferably 1.0 to 1.8.

[0022] The I / O value can be calculated by the methods described in "Organic Conceptual Diagram" (written by Yoshio Koda, published by Sankyo Publishing Co., Ltd. (1984)); KUMAMOTO PHARMACEUTICAL BULLETIN, No. 1, Items 1 to 16 (1954); Chemistry Field, Vol. 11, No. 10, Items 719 to 725 (1957). Specifically, the I value and O value of the solvent can be calculated from various functional groups (substituents or bonds) constituting the molecular structure of the solvent. Then, the I / O value can be obtained by dividing the I value by the O value. The molecular structure of the solvent can be specified by GCMS.

[0023] The I value of a substituent or bond is a quantification of the influence of the substituent or bond on the boiling point, with the hydroxy group as a reference. Specifically, it refers to the quantification of the influence of the substituent or bond on the boiling point based on the numerical value of 100 for the influence of one hydroxy group.

[0024] The O value of a substituent or bond is defined based on the methylene group in the molecule, with the influence of the carbon atom representing the methylene group on the boiling point as a reference. Specifically, the O value of one carbon atom is defined as 20, and it refers to the quantification of the influence of the substituent or bond on the boiling point based on this numerical value.

[0025] The I value of the solvent represents the sum of the I values of various substituents or bonds in the solvent molecule; the O value of the solvent represents the sum of the O values of various substituents or bonds in the solvent molecule. The sum means the sum of the products of the I value or O value of various substituents or bonds and the number (per molecule).

[0026] Examples of solvents with an I / O value of 1.0 to 3.0 include Sulfoxides such as dimethyl sulfoxide (I / O value: 1.75, boiling point: 189 °C) with an I / O value of 1.0 to 3.0; Polyhydric alcohols with an I / O value of 1.0 to 3.0, such as 2,3-butanediol (I / O value: 2.5, boiling point: 177°C), triethylene glycol (I / O value: 2.0, boiling point: 285°C), polyethylene glycol (I / O value: 2.0, boiling point: 200°C or higher), trimethylolethane (I / O value: 3.0), diethylene glycol (I / O value: 2.75), dipropylene glycol (I / O value: 1.83), and tripropylene glycol (I / O value: 1.33); Polyhydric alcohol ethers with an I / O value of 1.0 to 3.0, such as ethylene glycol monoacetate (I / O value: 1.75, boiling point: 182°C), ethylene glycol monomethyl ether (I / O value: 2.0), ethylene glycol monoethyl ether (I / O value: 1.5), ethylene glycol monobutyl ether (I / O value: 1.0), diethylene glycol monomethyl ether (I / O value: 1.4), diethylene glycol monoethyl ether (I / O value: 1.17), and propylene glycol monoethyl ether (I / O value: 1.2); and Carboxylic acids with an I / O value of 1.0 to 3.0, such as butyric acid (I / O value: 1.875) and isobutyric acid (I / O value: 2.143). These solvents may be one type or two or more types.

[0027] In particular, from the viewpoint of enhancing the swelling properties of the fibers, solvents with an I / O value of 2.0 to 3.0 are preferred; from the viewpoint of enhancing the carrier properties of the disperse dye, solvents with an I / O value of 1.0 to 2.0 (preferably 1.0 or more and less than 2.0) are preferred.

[0028] Among these, sulfoxides, polyhydric alcohols, and polyhydric alcohol ethers are preferred, and sulfoxides (especially dimethyl sulfoxide) are more preferred from the viewpoint of easily swelling the fibers and improving color development.

[0029] The boiling point of the solvent is not particularly limited, but from the viewpoint of preventing the disperse dye incorporated into the fibers from escaping after transfer printing, it is preferable that it be below the transfer temperature, and more preferably lower than the transfer temperature. However, if the boiling point is too low, the solvent will volatilize too much during transfer, making it difficult to obtain the desired effect. Therefore, the boiling point of the solvent is preferably 10 to 25°C, more preferably 20 to 25°C, lower than the transfer temperature, for example, 175 to 190°C.

[0030] In other words, if solvent remains in the fabric after transfer printing, the fibers tend to remain swollen, and some of the (dyed) disperse dye can migrate to the fiber surface, potentially causing contamination. In contrast, if the boiling point of the solvent is below the transfer temperature, the solvent can be removed efficiently by the heat generated during transfer, thus reliably suppressing the migration of disperse dye after transfer and preventing contamination.

[0031] The content of the solvent with an I / O value of 1.0 to 3.0 is not particularly limited, but is preferably 5% by mass or more relative to the pretreatment solution, more preferably 50 to 100% by mass, even more preferably 65 to 100% by mass, and particularly preferably 98 to 100% by mass. If the solvent content is above the lower limit, the carrier properties of the disperse dye and the swelling properties of the fibers are more easily enhanced, and if it is below the upper limit, the friction fastness is less likely to be impaired.

[0032] 1-2. Other ingredients The pretreatment solution may further contain other components besides those mentioned above. Examples of other components include other solvents besides the solvent mentioned above, water, surfactants, preservatives, pH adjusters, etc.

[0033] (Other solvents) The pretreatment solution may further contain other solvents, other than those mentioned above, from the viewpoint of adjusting surface tension and boiling point, as long as it does not impair the effects of the present invention. The other solvents are solvents with an I / O value of less than 1.0 or greater than 3.0. These solvents are preferably water-soluble organic solvents.

[0034] Examples of such solvents include alcohols (e.g., methanol, ethanol, propanol, pentanol, hexanol, cyclohexanol, benzyl alcohol), polyhydric alcohols (e.g., ethylene glycol, propylene glycol, polypropylene glycol), and polyhydric alcohol ethers (e.g., ethylene glycol monoethyl ether, ethylene glycol monophenyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, propylene glycol monomethyl ether).

[0035] The content of other solvents depends on their I / O values, but it is preferable that it be equivalent to or less than the content of solvents with an I / O value of 1.0 to 3.0. Specifically, if the mixture includes other solvents with an I / O value of less than 1.0, the ratio (mass ratio) of solvents with an I / O value of less than 1.0 to solvents with an I / O value of 1.0 to 3.0 may be 1:1 to 1:99. If the mixture includes other solvents with an I / O value greater than 3.0, the ratio (mass ratio) of solvents with an I / O value greater than 3.0 to solvents with an I / O value of 1.0 to 3.0 may be 35:65 to 1:99.

[0036] (Surfactants) The pretreatment solution preferably further contains a surfactant, from the viewpoint of reducing surface tension and improving penetration into the fabric and fibers. The surfactant may be nonionic, anionic, cationic, or betaine (amphoteric), but if the ink component contains an anionic compound, it is preferable that the surfactant be anionic, nonionic, or betaine.

[0037] Examples of such surfactants include fluorinated surfactants, silicone surfactants, sulfate ester salts such as dioctyl sulfosuccinate and sodium dodecyl sulfate (anionic surfactants), polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, acetylene glycols, oxyethylene adducts of acetylene glycols, Pluronic surfactants (Pluronic is a registered trademark), and nonionic surfactants such as sorbitan derivatives.

[0038] In particular, fluorine-based surfactants or silicone-based surfactants are more preferable from the viewpoint of easily reducing the surface tension of the pretreatment solution and improving its permeability.

[0039] Fluorine-based surfactants are surfactants that have a perfluoroalkyl group or perfluoroalkenyl group in their molecule. Examples include perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers. Commercially available products include Polyfox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omnova), and Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.).

[0040] Silicone-based surfactants are surfactants that have a polysiloxane structure in their molecules, and examples include polysiloxane oxyethylene adducts (polyether-modified organosiloxanes). Examples of commercially available products include BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-348 (trade names, manufactured by BYK), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, and KF-6017 (trade names, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0041] The surfactant content should be within the range that the surface tension of the pretreatment solution falls within the above range, for example, 0.05 to 2% by mass, preferably 0.5 to 1% by mass, relative to the pretreatment solution.

[0042] (Preservative) Examples of preservatives include aromatic halogen compounds (e.g., Preventol CMK), methylenedithiocyanates, halogenated nitrogen-sulfur compounds, and 1,2-benzisothiazolin-3-one (e.g., PROXEL GXL).

[0043] (pH adjuster) Examples of pH adjusters include citric acid, sodium citrate, hydrochloric acid, and sodium hydroxide.

[0044] 1-3. Physical Properties The surface tension of the pretreatment solution at 25°C is less than 38 mN / m. By making the surface tension of the pretreatment solution less than 38 mN / m, even if the pretreatment solution contains a solvent with an I / O value of 1.0 to 3.0, the pretreatment solution can penetrate well into fabrics made of natural fibers, synthetic cellulose fibers, etc., and into the interior of those fibers. This makes it easier for the disperse dye to enter the interior of the fibers and reduces the amount of disperse dye remaining on the surface of the fibers, thereby further increasing the color intensity and further improving friction fastness. From a similar viewpoint, the surface tension of the pretreatment solution is preferably 35 mN / m or less, more preferably 30 mN / m or less, and even more preferably 28 mN / m or less. The lower limit of the surface tension is preferably 25 mN / m or more from the viewpoint of not reducing the surface color intensity.

[0045] The surface tension of the pretreatment solution can be measured at 25°C using a surface tensimeter in accordance with JIS K2241 and the Wilhelmy method.

[0046] The surface tension of the pretreatment solution can be adjusted by the type and amount of solvent with an I / O value of 1.0 to 3.0, the ratio of that solvent to other solvents, and the type and amount of surfactant. For example, increasing the amount of solvent with an I / O value of 1.0 to 3.0 or increasing the amount of surfactant tends to lower the surface tension.

[0047] 2. Image forming method The image forming method of the present invention comprises 1) a step of applying a pretreatment solution to a fabric containing natural fibers or synthetic cellulose fibers (pretreatment step), and 2) a step of transferring an ink layer containing a disperse dye to the fabric to which the pretreatment solution has been applied (transfer printing step).

[0048] 1) Pretreatment process First, the pretreatment solution of the present invention is applied to at least a portion of the surface of the fabric. This results in a pretreated fabric.

[0049] <Fabric> The fabric contains natural fibers or synthetic cellulose fibers. Examples of natural fibers include cotton, linen, wool, and silk. Among these, cotton and synthetic cellulose fibers are preferred.

[0050] The fabric may contain two or more types of natural fibers, or it may contain natural fibers or synthetic cellulose fibers and other fibers. Examples of other fibers include chemical fibers such as rayon, vinylon, nylon, acrylic, polyurethane, polyester, and acetate.

[0051] The ratio of natural or synthetic cellulose fibers may be preferably 35% by mass or more, more preferably 50% by mass or more, and even more preferably 60% by mass or more, relative to the fibers constituting the fabric. For example, if the fabric contains cellulose fibers and polyester fibers, the ratio of cellulose fibers may be 35 to 100% by mass, and the ratio of polyester fibers may be 75 to 0% by mass.

[0052] The fabric may be made from these fibers in any form, such as woven, nonwoven, or knitted.

[0053] <Application of pretreatment solution> The pretreatment solution is applied to at least a portion of the surface of the fabric. The pretreatment solution may be applied to the entire surface of the fabric, or selectively to only the area to be dyed.

[0054] The method of applying the pretreatment solution is not particularly limited and may be any of the following: spray method, mangle method (pad method or dipping method), coating method, or inkjet method. For example, in the image forming method described later, the inkjet method is preferred from the viewpoint of being able to perform the process continuously with the ink application step, and the mangle method or coater method is preferred from the viewpoint of applying a predetermined amount of pretreatment solution in a short time.

[0055] In the mangle process, the amount of pretreatment solution applied is adjusted by immersing the fabric in a pretreatment solution stored in a bathtub and then squeezing it. The temperature of the pretreatment solution is not particularly limited, but can be between 15 and 30°C. The conditions in the inkjet process can be the same as those for applying ink in the dyeing process.

[0056] The amount of pretreatment solution applied is not particularly limited and can be adjusted according to the composition of the pretreatment solution and the amount of disperse dye to be applied. For example, the amount of pretreatment solution applied is set to 20 to 100% by mass, preferably 30 to 80% by mass, relative to the untreated fabric. When the amount of solvent applied is within this range, the carrier properties of the disperse dye into the fibers of the fabric are good during the transfer printing process, making it easier for the dye to penetrate into the interior of the fibers. In the mangle method, the amount of pretreatment solution applied is also referred to as the pick-up rate.

[0057] In particular, the amount of solvent with an I / O value of 1.0 to 3.0 is set to 10 to 100% by mass, preferably 20 to 80% by mass, relative to the untreated fabric.

[0058] Furthermore, drying is permitted under conditions that at least a portion of the solvent from the pretreatment solution applied to the fabric remains. Drying methods may include, for example, heat drying using hot air, a hot plate, or a heat roller. However, in order to avoid impairing the effect of improving the carrier properties of the disperse dye on the fabric during the transfer printing process described later, it is preferable not to dry the fabric.

[0059] 2) Transfer printing process Next, an ink layer containing disperse dye (transfer image) is transferred to the pre-treated fabric. Specifically, the transfer image formed on the transfer medium is heat-transferred (sublimation transfer) onto the pre-treated fabric.

[0060] Heat transfer is preferably performed before the pretreatment solution applied to the fabric has completely dried, that is, while the solvent remains on the fabric. Specifically, it is preferable to perform heat transfer while maintaining an application amount of pretreatment solution of 20% by mass or more relative to the untreated fabric; in particular, an application amount of solvent with an I / O value of 1.0 to 3.0 of 10% by mass or more relative to the untreated fabric. This maintains a swollen state of the fabric fibers, and the solvent functions as a carrier for the transferred disperse dye, making it easier for the disperse dye to penetrate the fibers and increasing the color intensity.

[0061] The transfer image used is an ink layer containing a disperse dye formed on a transfer medium. Such a transfer image can be obtained by applying the ink containing the disperse dye onto the transfer medium, for example, by an inkjet method, and then drying it. The composition of the ink will be described in detail later.

[0062] The transfer medium is not particularly limited as long as it can form an ink layer on its surface and transfer that ink layer to a fabric, for example, one that does not interfere with the sublimation of the sublimation dye during transfer. Preferred transfer mediums include, for example, paper on which an ink-receiving layer is formed on its surface using inorganic fine particles such as silica, and examples include inkjet-specific paper and transfer paper.

[0063] Next, the surface of the transfer image on the transfer medium is brought into contact with the surface of the fabric treated with the pretreatment solution (pretreatment surface), and heat-pressed to transfer the image. This causes the disperse dye (sublimation dye) in the transfer image on the transfer medium to sublimate and transfer to the fabric treated with the pretreatment solution, thereby dyeing the fabric. As a result, the desired image is formed on the fabric.

[0064] The transfer temperature (hot press temperature) is preferably equal to or higher than the boiling point of the solvent contained in the pretreatment solution, for example, it can be 180 to 210°C.

[0065] Furthermore, the pressing pressure for flat molds is 200-500 g / cm². 2 For continuous applications, the load is 2-6 kg / cm². 2 It is preferable that this is the case. Also, the pressing time is preferably 30 to 180 seconds, although this depends on the temperature.

[0066] As described above, it is preferable that the boiling point of the solvent contained in the pretreatment solution is lower than the transfer temperature. As a result, some of the solvent will evaporate due to the heat during transfer, making it less likely that a large amount of solvent will remain after dyeing. This makes it less likely that the fibers will remain swollen, thus suppressing the leakage of the dyed disperse dye from the fibers. Therefore, even without post-treatment (such as application of resin solution or crosslinking agent) after the transfer printing process, contamination by disperse dye that has leaked out of the fibers can be suppressed.

[0067] The image forming method of the present invention may further include other steps as needed. Furthermore, from the viewpoint of preventing the dyed disperse dye from washing out of the fibers, it is preferable not to perform a step of washing the fabric after transfer printing (the fabric onto which the ink layer containing the disperse dye has been transferred).

[0068] 3. Ink The ink used to form the transfer image contains a disperse dye and water.

[0069] <Disperse dye> Disperse dyes are dyes that are insoluble or poorly soluble in water. Insoluble or poorly soluble in water means that their solubility in water at 25°C is 10 mg / L or less, preferably 5 mg / L or less, and more preferably 1 mg / L or less. It is preferable that the disperse dye is a sublimation dye that sublimes upon heating.

[0070] The types of disperse dyes are not particularly limited and can include azo dyes, anthraquinone dyes, etc. Examples of sublimation dyes among disperse dyes include the following:

[0071] CIDisperse Yellow3, 4, 5, 7, 9, 13, 24, 30, 33, 34, 42, 44, 49, 50, 51, 54, 56, 58, 60, 63, 6 4, 66, 68, 71, 74, 76, 79, 82, 83, 85, 86, 88, 90, 91, 93, 98, 99, 100, 104, 114, 116, 118, 119, 122, 124, 126, 135, 140, 141, 149, 160, 162, 163, 164, 165, 17 9, 180, 182, 183, 186, 192, 198, 199, 202, 204, 210, 211, 215, 216, 218, 224, etc.

[0072] CIDisperse Orange1, 3, 5, 7, 11, 13, 17, 20, 21, 25, 29, 30, 31, 32, 33, 37, 38, 42, 43, 44, 45, 47, 48, 49, 50, 53 , 54, 55, 56, 57, 58, 59, 61, 66, 71, 73, 76, 78, 80, 89, 90, 91, 93, 96, 97, 119, 127, 130, 139, 142, etc.

[0073] C.I. Disperse Red 1, 4, 5, 7, 11, 12, 13, 15, 17, 27, 43, 44, 50, 52, 53, 54, 55, 56, 58, 59, 60, 65, 72, 73, 74, 75, 76, 78, 81, 82, 86, 88, 90, 91, 92, 93, 96, 103, 105, 106, 107, 108, 110, 111, 113, 117, 118, 121, 122, 126, 127, 128, 131, 132, 134, 135, 137, 143, 145, 146, 151, 152, 153, 154, 157, 159, 164, 167, 169, 177, 179, 181, 183, 184, 185, 188, 189, 190, 191, 192, 200, 201, 202, 203, 205, 206, 207, 210, 221, 224, 225, 227, 229, 239, 240, 257, 258, 277, 278, 279, 281, 288, 289, 298, 302, 303, 310, 311, 312, 320, 324, 328, etc.

[0074] C.I. Disperse Violet 1, 4, 8, 23, 26, 27, 28, 31, 33, 35, 36, 38, 40, 43, 46, 48, 50, 51, 52, 56, 57, 59, 61, 63, 69, 77, etc.

[0075] C.I. Disperse Green 9, etc. C.I. Disperse Brown 1, 2, 4, 9, 13, 19, etc.

[0076] CIDisperse Blue3, 7, 9, 14, 16, 19, 20, 26, 27, 35, 43, 44, 54, 55, 56, 58, 60, 62, 64, 71, 72, 73, 75, 79, 81, 82, 83, 87, 91, 93, 94, 95, 96, 102, 106, 108, 112, 113, 115, 118, 120, 122, 125, 128, 130, 139, 141, 142, 143, 146, 148, 149, 153, 154, 158, 165, 167, 171, 173, 174, 176, 181, 183, 185, 186, 187, 189, 197, 198, 200, 201, 205, 207, 211, 214, 224, 225, 257, 259, 267, 268, 270, 284, 285, 287, 288, 291, 293, 295, 297, 301, 315, 330, 333, 359, 360, etc. CIDisperse Black1, 3, 10, 24 etc.

[0077] As mentioned above, the I / O value of disperse dyes is close to 1.0.

[0078] The molecular weight of the disperse dye is not particularly limited, but for example, when transferring ink applied to a transfer medium to fabric to form an image (sublimation printing), a small molecular weight (e.g., 200-350) is preferable from the viewpoint of facilitating the sublimation of the disperse dye. On the other hand, a moderately large molecular weight (e.g., 350-500) is preferable from the viewpoint of preventing the disperse dye that has penetrated the fabric from easily leaching out.

[0079] The disperse dyes contained in the ink may or may not be crystallized. The method of applying the ink to the transfer medium is not particularly limited, but for example, an inkjet method may be used because it enables high-precision image formation.

[0080] The average particle size of the disperse dye in the ink is not particularly limited, but from the viewpoint of injection stability in inkjet systems, it may be, for example, 300 nm or less. The average particle size can be determined using commercially available particle size analyzers that employ methods such as light scattering, electrophoresis, and laser Doppler. An example of a particle size analyzer is the Malvern Zetasizer 1000.

[0081] The content of disperse dye in the ink is not particularly limited, but it is preferably 2 to 10% by mass relative to the ink. If the disperse dye content is 2% by mass or more, it is easier to form high-density images, and if it is 10% by mass or less, the viscosity of the ink does not become too high, so the injection stability is not easily impaired. From the same viewpoint, the disperse dye content is more preferably 5 to 10% by mass relative to the ink.

[0082] <Solvent> The ink may further contain a solvent as needed. The solvent is not particularly limited, but is preferably a water-soluble organic solvent. The water-soluble organic solvent can be the same as the water-soluble organic solvent used in the pretreatment solution.

[0083] In particular, the solvent contained in the ink is preferably one that has the same or a similar I / O value as the solvent contained in the pretreatment solution, which has an I / O value of 1.0 to 3.0. Such a solvent can be the same as those exemplified above as solvents with an I / O value of 1.0 to 3.0. Alternatively, from the viewpoint of not easily impairing the injection stability in the inkjet method, it is preferable that the ink does not thicken easily upon drying, and therefore preferably contains a high-boiling-point solvent with a boiling point of 200°C or higher.

[0084] High-boiling point solvents 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 are preferably polyols or polyalkylene oxides. 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). 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.

[0085] The content of the water-soluble organic solvent is preferably 20 to 70% by mass relative to the ink. If the content of the water-soluble organic solvent is 20% by mass or more relative to the ink, the dispersibility and injection properties of the disperse dye are more easily improved, and if it is 70% by mass or less, the drying properties of the ink are less likely to be impaired. Furthermore, the total content of water and water-soluble organic solvent is preferably 90 to 98% by mass, and more preferably 90 to 95% by mass, relative to the ink.

[0086] <Other ingredients> Ink may contain other components as needed. Examples of other components include dispersants, surfactants, preservatives, and pH adjusters.

[0087] Dispersants can be selected according to the type of dispersant dye. Examples of dispersants include formalin condensates of sodium creosote oil sulfonate, formalin condensates of sodium cresol sulfonate and sodium 2-naphthol-6-sulfonate, formalin condensates of sodium cresol sulfonate, formalin condensates of sodium phenol sulfonate, formalin condensates of sodium β-naphthol sulfonate, formalin condensates containing sodium β-naphthalene sulfonate and sodium β-naphthol sulfonate, alkylene oxides containing ethylene oxide and propylene oxide, fatty alcohols, fatty amines, fatty acids, phenols, alkylphenols and alkylamines, alkylating compounds, lignin sulfonates, sodium paraffin sulfonate, and α-olefins. This includes copolymers of maleic anhydride and known comb-type block polymers.

[0088] Examples of comb-type block polymers include DISPERBYK-190, DISPERBYK-194N, DISPERBYK-2010, DISPERBYK-2015, and BYK-154 from BIC Chemie ("DISPERBYK" and "BYK" are registered trademarks of the company).

[0089] The amount of dispersant is not particularly limited, but 20 to 200 parts by mass per 100 parts by mass of disperse dye is preferred. If the amount of dispersant is 20 parts by mass or more, the dispersibility of the disperse dye tends to be higher, and if it is 200 parts by mass or less, the decrease in injection properties due to the dispersant tends to be suppressed.

[0090] The surfactants, preservatives, and pH adjusters used are the same as those used in the pretreatment solution.

[0091] <Ink properties> The viscosity of the 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. [Examples]

[0092] The present invention will be described below with reference to examples. The scope of the present invention is not to be limited by the examples.

[0093] 1. Preparation of pretreatment solution <Solvent> Dimethyl sulfoxide (I / O value 1.75, boiling point 189°C) 2,3-Butanediol (I / O value 2.5, boiling point 177°C) Diethylene glycol diethyl ether (I / O value 0.38, boiling point 188°C) Ethylene glycol monoacetate (I / O value 1.75, boiling point 182°C) Triethylene glycol (I / O value 2.0, boiling point 285°C) Polyethylene glycol (I / O value 2.0, boiling point over 200°C) Polypropylene glycol (I / O value 3.3, boiling point over 200°C) 3-Methoxybutyl acetate (I / O value 0.57, boiling point 171°C) Ethylene glycol (I / O value 5.0, boiling point 197°C) The I / O values ​​were determined by calculating the I and O values ​​for each solvent using the methods described above in the Organic Concept Diagram (by Yoshio Koda, Sankyo Publishing (1984)); KUMAMOTO PHARMACEUTICAL BULLETIN, No. 1, Sections 1-16 (1954); and The Field of Chemistry, Vol. 11, No. 10, Sections 719-725 (1957), and then taking their ratio.

[0094] <Surfactants> E1010: Acetylene-based surfactant (Nisshin Chemical Industry Co., Ltd.) KF-351A: Silicone-based surfactant (Shin-Etsu Chemical Co., Ltd.) PF-159: Fluorine-based surfactant (BASF Japan Ltd.) Asahi Guard AG-E550D: Fluorine-based water-repellent coating agent (Meisei Chemical Industry Co., Ltd.)

[0095] <Preparation of pretreatment solutions 1-20> Pretreatment solutions 1 to 20 were prepared by mixing a solvent, surfactant, and deionized water to the compositions shown in Tables 1 and 2 below.

[0096] <Measuring surface tension> The surface tension of the pretreatment solution was measured at 25°C in accordance with JIS K2241 using a Wilhelmie surface tensiometer manufactured by Kyowa Interface Science Co., Ltd.

[0097] The compositions of pretreatment solutions 1 to 10 are shown in Table 1; the compositions of pretreatment solutions 11 to 20 are shown in Table 2.

[0098] [Table 1]

[0099] [Table 2]

[0100] 2. Image Formation and Evaluation [Image Formation] <Tests 1-21> (1) Pretreatment Cotton broadcloth 40 (100% cotton, I / O value: 2.95) was used as the fabric. This fabric was immersed in a bathtub filled with the pretreatment solution prepared above, and then the excess pretreatment solution was squeezed out with a mangle roll at a pick-up rate of 80%. The temperature of the pretreatment solution in the bathtub was set to 20-25°C.

[0101] (2) Applying ink to the transfer paper Next, an inkjet printer equipped with an inkjet head (Konica Minolta head KM1024iMAE) was prepared as the image forming apparatus. Then, TexStylus Black ink manufactured by Systemgraphi was ejected from the nozzle of the inkjet head to form a solid image on A4 sublimation transfer paper with adhesive (manufactured by Systemgraphi). The ink in question contains a sublimation dye (I / O value: 0.5~1.1) as a disperse dye.

[0102] Specifically, an image (200mm x 200mm in total) including a fine grid, gradation, and solid areas was formed using a main scan of 540dpi and a sub-scan of 720dpi. dpi represents the number of ink droplets (dots) per 2.54cm. The ejection frequency was set to 22.4kHz. Afterwards, the ink-coated transfer paper was dried in a dryer at 50-80°C for 30 seconds.

[0103] (3) Transferring ink to fabric Next, the transfer paper coated with ink (ink layer) is pressed using a transfer device (heat press) at 200°C for 50 seconds at a pressure of 300 g / cm². 2 The fabric, with some of the pre-treatment solvent still present (approximately 80% pickup rate), was then heat-pressed onto it. This transferred the ink from the transfer paper onto the pre-treated fabric, resulting in an image-formed product.

[0104] <Rating> The image formations obtained in Tests 1-21 were evaluated for color density and friction fastness (wet friction, dry friction) using the following methods.

[0105] (Image density) Image density was measured using a spectrophotometer (manufactured by X-Rite), and the K / S value was calculated. The K / S value is an index of surface color density defined by the following formula. Kubelka-Munk formula: K / S = (1 - R) 2 / 2S (K: Absorption coefficient of light, S: Scattering coefficient of light, R: Surface reflectance) A higher K / S value indicates higher color density, while a lower K / S value indicates lower color density. 5: K / S value is 16 or higher 4: K / S value is between 14 and 16. 3: K / S value is 12 or higher but less than 14 2: K / S value is between 10 and 12. 1: K / S value is less than 10

[0106] (Dry / wet friction fastness) The obtained image formations were evaluated for dry friction fastness and wet friction fastness using a clock meter (friction tester type I) in accordance with JIS L 0849. A grayscale for staining based on JIS 0805 was used as the evaluation fabric, and the grade was determined and evaluated using the following indicators. 5: The number of series is 4 or more. 4: The number of units is 3.5 or less. 3: The number of series is 3 or less. 2: The number of units is 2.5 or less. 1: The series is 2 or less.

[0107] The evaluation results for Tests 1-21 are shown in Table 3.

[0108] [Table 3]

[0109] As shown in Table 3, in tests 1 to 12, using pretreatment solutions 1 to 10, 17, and 20 containing a solvent with an I / O value of 1.0 to 3.0 and a surface tension of less than 38 mN / m, it can be seen that image-forming products with high color density and high friction fastness can be obtained.

[0110] In contrast, tests 14-17 (comparative examples) using pretreatment solutions 11-14, which contain a solvent with an I / O value of 1.0-3.0 but have a surface tension of 38 mN / m or higher, show particularly low friction fastness. This is thought to be because the pretreatment solution did not penetrate sufficiently into the fabric or fibers, and therefore the disperse dye could not penetrate into the fabric or fibers during transfer printing, remaining on the fiber surface.

[0111] Furthermore, in Test 13 (Comparative Example), where no pretreatment was performed, it was found that the color development was low. Also, since the dye that did not stain remained on the transfer substrate side without being transferred, the friction fastness was found to be 5.

[0112] Furthermore, in pre-treated tests 15 and 16 (comparative examples), both color development and abrasion fastness were found to be low. The reason for this is presumed to be as follows: Polyethylene glycol and polypropylene glycol have large molecular weights, making them difficult to penetrate into the interior of the fibers. Also, these solvents have virtually no boiling point, so they tend to remain on the fiber surface as a dyeable layer (dyeable region) even after transfer. Therefore, the disperse dyes tend to adhere to the dyeable layer on the fiber surface rather than to the interior of the fiber; in the abrasion fastness test, the dyeable layer is peeled off along with the dye when rubbed, resulting in low abrasion fastness.

[0113] Furthermore, in tests 18 and 19 (comparative examples) using solvent-free pretreatment solutions 15 and 16 with I / O values ​​of 1.0 to 3.0, both color development density and friction fastness were found to be low. In particular, since pretreatment solution 15 contains less solvent and more water, it is thought that the color development was low in test 18 using it.

[0114] Furthermore, it was found that in Test 20, which used pretreatment solution 18 containing only solvents with an I / O value of less than 1.0, the color development was poor, and in Test 21, which used pretreatment solution 19 containing only solvents with an I / O value of more than 3.0, the friction fastness was poor.

[0115] Furthermore, it can be seen that test 10, using pretreatment solution 3 with DMSO, exhibits superior color development compared to test 12, which used pretreatment solution 20 with ethylene glycol monoacetate. [Industrial applicability]

[0116] According to the present invention, it is possible to provide a pretreatment solution and an image forming method that can form images with high color density and friction fastness even on fabrics containing hydrophilic fibers such as natural fibers.

Claims

1. A pretreatment solution for fabrics used in transfer printing, The pretreatment solution contains 50% by mass or more of a solvent having an organic / inorganic value (I / O value) of 1.0 to 3.0, and the solvent contains sulfoxides having an I / O value of 1.0 to 3.

0. The surface tension at 25°C is less than 38 mN / m. Pretreatment solution.

2. A pretreatment solution for fabrics used in transfer printing, A solvent having an organic / inorganic value (I / O value) of 1.0 to 3.0 is contained in an amount of 50% by mass or more relative to the pretreatment liquid, and has a surface tension of 28 mN / m or less at 25°C. Pretreatment solution.

3. The solvent comprises one or more selected from the group consisting of sulfoxides, polyhydric alcohols, and polyhydric alcohol ethers, having an I / O value of 1.0 to 3.

0. The pretreatment solution according to claim 2.

4. The boiling point of the aforementioned solvent is below the transfer temperature. The pretreatment solution according to any one of claims 1 to 3.

5. The aforementioned pretreatment solution further contains a surfactant. The pretreatment solution according to any one of claims 1 to 4.

6. A step of applying a pretreatment solution according to any one of claims 1 to 5 to a fabric containing natural fibers or synthetic cellulose fibers, The process involves transferring an ink layer containing a disperse dye onto a fabric to which the aforementioned pretreatment solution has been applied, including, Image forming method.

7. The aforementioned fabric contains cotton or synthetic cellulose fibers. The image forming method according to claim 6.

8. The process does not include washing the fabric to which the ink layer containing the aforementioned disperse dye has been transferred. The image forming method according to claim 6 or 7.

Images