Transfer sheet and method for manufacturing same

Abstract

The present disclosure addresses the problem of providing a transfer sheet excellent in transferability and capable of enhancing the texture and durability (in particular, preferably, washing fastness and tumble-drying fastness) of a transfer-printed item to be obtained. The problem can be solved by using a transfer sheet in which an image forming layer, a white printing layer containing a white pigment and a resin, and an adhesive layer containing an adhesive resin are laminated in this order on an ink-receiving layer formation surface of a transfer substrate having an inkjet ink-receiving layer. The film thickness A of the white printing layer is 5-35 μm, the film thickness B of the adhesive layer is 5-50 μm, and the thickness C of the transfer sheet is 25-200 μm.

Description

Transfer sheet and method of manufacturing the same

[0001] The present disclosure relates to a transfer sheet and a method for producing the same.

[0002] A known method for printing an image is to form an image on a transfer substrate, and then overlay a transfer sheet on which an adhesive layer is formed on the transfer substrate, thereby transferring the image to a transfer medium. Conventionally, the adhesive layer has been formed by sprinkling a hot-melt resin powder on the image formed on the transfer substrate, melting the resin powder by heat treatment, and then drying. However, the thickness of such an adhesive layer tends to be thick because it depends on the particle size of the resin powder, which has led to the problem of poor texture in the resulting transfer print.

[0003] On the other hand, development of transfer sheets manufactured without using powder is also progressing. For example, Patent Document 1 discloses a transfer sheet manufactured by ejecting an aqueous ink onto a peelable support by an inkjet method to form an image, and ejecting an aqueous adhesive liquid containing two types of resins having specific glass transition temperatures by the inkjet method so as to at least partially overlap the image.

[0004] JP 2024-17827 A

[0005] In transfer printing, not only is excellent transferability required, but the durability of the printed matter obtained by transferring the image to a receiving medium (hereinafter referred to as a transfer printed matter) may also be required. For example, if the receiving medium is a fabric, it is expected that the transfer printed matter will be washed or tumble dried, so excellent wash fastness and tumble drying fastness (hereinafter referred to as wash / tumble drying fastness) are also required. Furthermore, if the receiving medium is a fabric, for example, the resulting transfer printed matter is also required to have a good texture. However, while Patent Document 1 describes that the resulting transfer printed matter has good wash fastness, it does not examine the compatibility of transferability and texture with wash / tumble drying fastness, which is durability under more severe conditions.

[0006] Therefore, an object of the present disclosure is to provide a transfer sheet that has excellent transferability and can improve the texture and durability (particularly preferably the wash and tumble dry fastness) of the resulting transfer print.

[0007] As a result of extensive research to solve the above-mentioned problems, the inventors discovered that by adjusting the film thickness of the white printing layer that forms the base of the image, the film thickness of the adhesive layer, and the thickness of the transfer sheet, it is possible to improve transferability, as well as the texture and durability (particularly preferably washing and tumble drying fastness) of the resulting transfer print, and thus completed the present invention.

[0008] That is, the contents of the present disclosure are as follows. [1] A transfer sheet comprising an image forming layer, a white printed layer containing a white pigment and a resin, and an adhesive layer containing an adhesive resin laminated in this order on the ink-receiving layer-forming surface of a transfer substrate having an ink-jet ink-receiving layer, wherein the thickness A of the white printed layer is 5 to 35 μm, the thickness B of the adhesive layer is 5 to 50 μm, and the thickness C of the transfer sheet is 25 to 200 μm. [2] The transfer sheet according to [1], wherein the ratio (A / B) of the thickness A of the white printed layer to the thickness B of the adhesive layer is 0.2 to 4.0. [3] The transfer sheet according to [1] or [2], wherein the transfer substrate is paper or a resin film having an ink-jet ink-receiving layer. [4] The transfer sheet according to any of [1] to [3], wherein the adhesive resin contained in the adhesive layer is at least one selected from the group consisting of acrylic resins, polyester resins, and polyurethane resins. [5] The transfer sheet according to any one of [1] to [4], wherein the adhesive resin contained in the adhesive layer has a glass transition temperature higher than the glass transition temperature of the resin contained in the white print layer. [6] The transfer sheet according to any one of [1] to [5], wherein the adhesive resin contained in the adhesive layer has a weight average molecular weight of 5,000 to 700,000. [7] The transfer sheet according to any one of [1] to [6], wherein the adhesive resin contained in the adhesive layer has a molecular weight distribution of 4 to 12. [8] The transfer sheet according to any one of [1] to [7], wherein the image forming layer contains a colorant and a resin. [9] The transfer sheet according to any one of [1] to [8], wherein the transfer sheet is used for transfer onto fabric.

[10] The transfer sheet according to any one of [1] to [9], wherein the adhesive resin contained in the adhesive layer has a glass transition temperature of -50 to 35°C.

[11] The transfer sheet according to any one of [1] to

[10] , wherein the resin contained in the white print layer has a glass transition temperature of -50 to 10°C.

[12] The transfer sheet according to any one of [1] to

[11] , wherein the resin contained in the white print layer is at least one selected from an acrylic resin, a polyester resin, and a urethane resin.

[13] The transfer sheet according to any one of [1] to

[12] , wherein the resin contained in the white print layer and the adhesive resin contained in the adhesive layer are both acrylic resins.

[14] The adhesive resin contained in the adhesive layer is an acrylic resin, and the acrylic resin comprises a structural unit derived from a low Tg (meth)acrylic acid alkyl ester having a glass transition temperature of −20° C. or lower of a homopolymer, and methacrylic acid C. 1-5

[15] The transfer sheet according to any one of [1] to

[13] , which contains a structural unit derived from an alkyl ester and / or a styrene-based monomer and a structural unit derived from an acid group-containing monomer.

[15] The resin contained in the white print layer is an acrylic resin, and the acrylic resin contains a structural unit derived from a low Tg (meth)acrylic acid alkyl ester whose homopolymer has a glass transition temperature of −20° C. or lower and a structural unit derived from a methacrylic acid C 1-5

[16] The transfer sheet according to any one of [1] to

[15] , which contains a structural unit derived from an alkyl ester and / or a styrene-based monomer and a structural unit derived from an acid group-containing monomer.

[17] A method for producing a transfer sheet according to any one of [1] to

[16] , comprising the steps of: inkjet printing by ejecting an image forming ink onto an ink-receiving layer-forming surface of a transfer substrate having an inkjet ink-receiving layer; inkjet printing by ejecting a white ink containing a white pigment and a resin onto the surface printed with the image forming ink; and inkjet printing by ejecting an adhesive ink containing an adhesive resin onto the surface printed with the white ink, in this order; wherein the film thickness A of the white printed layer formed from the white ink is 5 to 35 μm, the film thickness B of the adhesive layer formed from the adhesive ink is 5 to 50 μm, and the thickness C of the transfer sheet is 25 to 200 μm.

[18] The manufacturing method according to

[17] , wherein the image-forming ink, the white ink, and the adhesive ink are each an ink containing water and a water-soluble organic solvent.

[0009] According to the present disclosure, it is possible to provide a transfer sheet that can improve transferability, as well as the texture and durability (particularly preferably, washing and tumble drying fastness) of the resulting transfer print.

[0010] FIG. 1 is a schematic cross-sectional view showing an example of a laminate structure of a transfer sheet according to the present disclosure.

[0011] An embodiment of the present disclosure will be described below, but the contents of the present disclosure are not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B." Furthermore, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylate" means acrylate or methacrylate. The same applies to terms such as "(meth)acryloxy" and "(meth)acryloyl." Furthermore, a "structural unit derived from" corresponds to a structure in which the carbon-carbon double bond in each monomer component is replaced with a carbon-carbon single bond and two bonds bonded to the respective carbons.

[0012] 1. Transfer Sheet The transfer sheet of the present disclosure comprises an inkjet ink receiving layer (hereinafter sometimes simply referred to as the "ink receiving layer") formed on a transfer substrate having an ink receiving layer surface, and an image forming layer, a white printed layer containing a white pigment and a resin, and an adhesive layer containing an adhesive resin laminated in this order on the ink receiving layer forming surface. The ink receiving layer absorbs ink ejected onto the ink receiving layer (specifically, ink ejected onto the ink receiving layer by inkjet printing). Therefore, a portion of the image forming layer may be formed within the ink receiving layer, the entire image forming layer may be formed (with the white printed layer formed outside the ink receiving layer), the entire image forming layer and a portion of the white printed layer may be formed, the entire image forming layer and the entire white printed layer may be formed (with the adhesive layer formed outside the ink receiving layer), or the entire image forming layer, the entire white printed layer, and a portion of the adhesive layer may be formed.

[0013] FIG. 1 is a schematic cross-sectional view showing an example of the laminate structure of a transfer sheet according to the present disclosure. The transfer sheet 100 according to the present disclosure comprises a transfer substrate 1 having an ink-receiving layer 1a on its surface, an image-forming layer 2 formed on the ink-receiving layer 1a side of the transfer substrate 1, a white printed layer 3 formed on the image-forming layer 2, and an adhesive layer 4 formed on the white printed layer 3. The adhesive layer 4 may be formed only in the areas where the image-forming layer 2 and the white printed layer 3 are formed, as shown in FIG. 1, or it may be formed in addition to the areas where the image-forming layer 2 and the white printed layer 3 are formed, as well as around them. Forming the adhesive layer 4 around the image-forming layer 2 and the white printed layer 3 further improves the durability (preferably washing and tumble drying fastness) of the resulting transfer print.

[0014] Fig. 1(a) shows an embodiment in which a portion of the image-forming layer 2 is formed in the ink-receiving layer 1a, Fig. 1(b) shows an embodiment in which the entire image-forming layer 2 is formed in the ink-receiving layer 1a (with the exception that the white printed layer 3 is formed outside the ink-receiving layer 1a), Fig. 1(c) shows an embodiment in which the entire image-forming layer 2 and a portion of the white printed layer 3 are formed in the ink-receiving layer 1a, Fig. 1(d) shows an embodiment in which the entire image-forming layer 2 and the entire white printed layer 3 are formed in the ink-receiving layer 1a (with the exception that the adhesive layer 4 is formed outside the ink-receiving layer 1a), and Fig. 1(e) shows an embodiment in which the entire image-forming layer 2, the entire white printed layer 3, and a portion of the adhesive layer 4 are formed in the ink-receiving layer 1a. Among these, from the viewpoint of enhancing durability, the embodiments of Figs. 1(a), 1(b), and 1(c) are preferred.

[0015] The white printed layer serves as a base layer for the image-forming layer on which the desired image, such as characters or a pattern, is formed. The concealing properties of the white printed layer can enhance the color development of the image. The present disclosure has discovered that adjusting the film thickness A of the white printed layer to 5 to 35 μm can improve the durability (particularly, washing and tumble drying fastness) of the resulting printed matter. The film thickness A of the white printed layer is preferably 5 to 35 μm, more preferably 10 to 35 μm, and even more preferably 15 to 30 μm, and may be 18 to 30 μm. Adjusting the film thickness A to the above-mentioned lower limit or greater increases the strength and improves the washing and tumble drying fastness. Furthermore, adjusting the film thickness A to the above-mentioned upper limit or less can prevent the white printed layer from becoming too hard, thereby suppressing image cracking and the like even under harsh conditions such as washing and tumble drying.

[0016] The adhesive layer serves to adhere the image to the transfer medium during transfer printing. In the present disclosure, it has been discovered that adjusting the film thickness B of this adhesive layer to 5 to 50 μm improves transferability and the texture of the resulting transfer print. In the present disclosure, the film thickness B of the adhesive layer refers to the film thickness of the adhesive layer formed on the white print layer. The film thickness B of the adhesive layer is preferably 5 to 50 μm, more preferably 10 to 45 μm, and even more preferably 15 to 35 μm. By adjusting the film thickness B to the above-mentioned lower limit or above, transferability can be improved. Furthermore, by adjusting the film thickness B to the above-mentioned upper limit or below, the texture of the resulting transfer print can be improved.

[0017] The ratio (A / B) of the thickness A of the white printing layer to the thickness B of the adhesive layer is preferably 0.2 to 4.0, more preferably 0.3 to 3.0, and even more preferably 0.5 to 2.0, and may be 0.5 to 1.5 or 0.5 to 1.0. By adjusting this thickness ratio to equal to or greater than the lower limit, strength is increased and washing and tumble drying fastness is further improved. Furthermore, by adjusting this thickness ratio to equal to or less than the upper limit, the image can be prevented from becoming too hard, and cracking of the image can be further suppressed even under harsh conditions such as washing and tumble drying.

[0018] The thickness C of the transfer sheet is preferably 25 to 200 μm, more preferably 50 to 160 μm, and even more preferably 80 to 140 μm. Adjusting the thickness C to above the lower limit improves the sheet's handling properties. Adjusting the thickness C to below the upper limit facilitates heat transfer during transfer printing, improving transferability. Adjusting the thickness C to 140 μm or less in particular facilitates heat transfer during transfer printing, potentially enabling the adhesive layer to be firmly attached or embedded in the transfer medium, further improving the washing and tumble drying durability of the resulting transfer print. The thickness A of the white printing layer, the thickness B of the adhesive layer, and the thickness C of the transfer sheet can each be determined by the measurement methods described in the Examples.

[0019] The transfer substrate is preferably formed from an ink-receiving layer and a base layer serving as a base material. The film thickness of the transfer substrate may be appropriately adjusted so that the thickness C falls within the above-mentioned range, and is, for example, 10 to 150 μm, preferably 20 to 120 μm, more preferably 30 to 100 μm, and even more preferably 30 to 80 μm.

[0020] The ink-receiving layer can prevent the image-forming ink used to form the image-forming layer from flowing or crumbling, and can further increase the durability of the image-forming layer in the transfer-printed product. The film thickness of the ink-receiving layer can also be appropriately adjusted so that the thickness C falls within the above-mentioned range, for example, 0.05 to 20 μm, preferably 0.5 to 15 μm, and more preferably 1 to 10 μm. By adjusting the film thickness of the ink-receiving layer to be equal to or greater than the above-mentioned lower limit, the flow of the image-forming ink can be suppressed, and by adjusting the film thickness to be equal to or less than the above-mentioned upper limit, manufacturing costs can be reduced. The film thickness of the transfer substrate, the film thickness of the ink-receiving layer, and the thickness of the base material layer serving as the base material can each be determined using the measurement methods described in the Examples.

[0021] The transfer sheet of the present disclosure may further include layers other than the transfer substrate, image-forming layer, white printing layer, and adhesive layer, as long as the transfer substrate, image-forming layer, white printing layer, and adhesive layer are laminated in this order. Examples of such layers include a release layer and a protective layer.

[0022] When the transfer sheet of the present disclosure has a release layer, the release layer is preferably provided between the substrate layer serving as the base material of the transfer substrate and the ink-receiving layer and / or on the substrate layer opposite the surface on which the ink-receiving layer is formed. By providing a release layer between the substrate layer and the ink-receiving layer, the substrate layer can be easily peeled from the image-forming layer to be transferred, thereby facilitating transfer. Furthermore, by providing a release layer on the substrate layer opposite the surface on which the ink-receiving layer is formed, blocking between the transfer sheets can be suppressed when the transfer sheets are stacked.

[0023] When the transfer sheet of the present disclosure has a release layer, the thickness of the release layer is not particularly limited, but is preferably 10 nm or more, more preferably 30 nm or more, from the viewpoint of further improving transferability, and is preferably 2 μm or less from the viewpoint of suppressing bulkiness when made into a roll-shaped transfer sheet. That is, the thickness of the release layer is preferably 10 nm to 2 μm or 30 nm to 2 μm. The thickness of the release layer can be determined by the same measurement methods as those for the film thickness A of the white printing layer, the film thickness B of the adhesive layer, and the thickness C of the transfer sheet described in the Examples.

[0024] 2. Composition of Each Layer The composition of each layer will now be described.

[0025] 2-1 Transfer Substrate The transfer substrate has an ink-receiving layer, and is preferably formed from the ink-receiving layer and a base layer serving as a base material.

[0026] The ink-receiving layer is not particularly limited, and a known ink-receiving layer provided in an inkjet recording material can be used. The ink-receiving layer usually contains one or more resins, and examples of such resins include (meth)acrylic resins such as (meth)acrylic acid ester resins and (meth)acrylic acid ester-styrene copolymer resins; olefin resins such as polyethylene resins and polypropylene resins; silicone resins; polyvinyl alcohol resins; and wax resins. Preferred wax resins include microcrystalline wax, paraffin wax, synthetic wax, modified synthetic wax, and carnauba wax. Specific examples include EMUSTAR-042X, EMUSTAR-1155, EMUSTAR-0135, EMUSTAR-6315, EMUSTAR-1309, and EMUSTAR-0413 manufactured by Nippon Seiro Co., Ltd.

[0027] In order to enhance ink absorption, the ink receiving layer preferably further contains one or more inorganic particles such as alumina, alumina hydrate, silica, calcium carbonate, magnesium carbonate, and titanium dioxide, with silica being preferred.

[0028] The content of the inorganic particles in the ink receiving layer is not particularly limited, but is preferably 25 to 400 parts by mass, more preferably 33 to 300 parts by mass, per 100 parts by mass of the resin.

[0029] The content of inorganic particles in the ink-receiving layer is, for example, 0.1 to 20% by mass, preferably 0.5 to 10% by mass, and more preferably 1.0 to 5% by mass, based on 100% by mass of the ink-receiving layer. By adjusting the content of inorganic particles to be equal to or greater than the lower limit, ink absorbency is further improved, and by adjusting the content to be equal to or less than the upper limit, a decrease in the water resistance of the resulting transfer print can be suppressed.

[0030] The ink receiving layer may further contain a flocculant, which inhibits bleeding of the image forming ink used to form the image forming layer, thereby improving ink receptivity.

[0031] The aggregating agent is preferably a component that aggregates components such as coloring materials (particularly pigments) contained in the image-forming ink. Specifically, the aggregating agent is preferably a cationic compound, and more preferably a water-soluble cationic compound.

[0032] The cationic compound may be a metal salt, a cationic polymer, or the like, and a metal salt is particularly preferred.The ink receiving layer may contain one or more types of coagulants.

[0033] The metal salt is preferably a polyvalent metal salt composed of a divalent or higher metal ion and an anion. Examples of metals constituting the divalent or higher metal ion include metals of Group 2 of the periodic table, such as magnesium, calcium, strontium, and barium; and transition metals (preferably transition metals of the fourth period), such as titanium, chromium, copper, and zinc. Among these, metals of Group 2 of the periodic table are preferred, and calcium is more preferred, because they have particularly excellent aggregating properties for pigments and the like. Examples of the anion include halide ions such as chloride ions, bromide ions, and iodide ions, nitrate ions, sulfate ions, acetate ions, carbonate ions, and hydroxide ions. Among these, chloride ions and sulfate ions are preferred. Specific examples of the polyvalent metal salt include metal salts of Group 2 of the periodic table, such as calcium salts (calcium chloride, calcium nitrate, calcium acetate, etc.), magnesium salts (magnesium chloride, magnesium acetate, magnesium sulfate, etc.), and barium salts (barium chloride, etc.); and transition metal salts, such as zinc salts (zinc chloride, zinc sulfate, etc.) and copper salts (copper nitrate, etc.).

[0034] The cationic polymer is preferably a water-soluble polymer having a cationic group. Examples of the cationic group that the cationic polymer has include an amino group, an ammonium group, an amide group, an imino group, a hydrazino group, and a -NHCONH group. Examples of the cationic polymer include polyallylamine, polyvinylamine, polyethyleneimine, and polydiallyldimethylammonium chloride.

[0035] The content of the flocculant is, for example, 0 to 50 parts by mass, preferably 0.1 to 40 parts by mass, more preferably 1 to 30 parts by mass, and even more preferably 3 to 15 parts by mass, relative to 100 parts by mass of the resin.

[0036] The ink receiving layer preferably contains at least a resin, more preferably contains a resin and inorganic particles and / or a flocculant, and even more preferably contains a resin and inorganic particles.

[0037] The total content of the resin, inorganic particles, and aggregating agent in the ink receiving layer is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may be 100% by mass.

[0038] The ink-receiving layer may contain one or more additives other than the resin, inorganic particles, and aggregating agent described above, such as surfactants, pH adjusters, dispersants, UV absorbers, UV stabilizers, thickeners, wetting agents, plasticizers, stabilizers, antifoaming agents, antioxidants, crosslinking agents, crosslinking accelerators, preservatives, chain transfer agents, and chelating agents.

[0039] The ink-receiving layer can be formed by a known method, for example, by coating a base layer with a solution containing components constituting the ink-receiving layer, such as at least one component selected from the resin, inorganic particles, aggregating agent, and other additives.

[0040] The material of the substrate layer is not particularly limited, but is preferably a material that does not shrink easily during the drying process in the production of the transfer sheet.Specific examples of the material of the substrate layer include metal, wood, resin (plastic), and paper.Examples of the metal include aluminum and copper, with aluminum being preferred from the viewpoint of cost.Examples of the resin include polyolefin resin, polyester resin, polyamide resin, and polycarbonate resin, with polyester resin being preferred from the viewpoint of cost, and aromatic polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate being more preferred.Examples of the paper include plain paper, high-quality paper, and coated paper.

[0041] In particular, the base layer is preferably a resin film or paper from the viewpoint of cost, and more preferably a polyester resin film from the viewpoint of good heat resistance, further preferably an aromatic polyester film, and particularly preferably a polyethylene terephthalate film.

[0042] The substrate layer may have a single layer structure or a laminated structure.

[0043] 2-2. Image-Forming Layer 2-2-1. Coloring Material The image-forming layer is a layer on which the desired image is formed, and typically contains a coloring material. The coloring material contained in the image-forming layer is not particularly limited, and coloring materials used in typical inkjet inks can be used. The coloring material may be a dye or a pigment, but is preferably a pigment from the viewpoint of further enhancing the fastness of the resulting transfer print. Examples of the pigment include organic pigments and inorganic pigments, which may be used alone or in combination of two or more types. Furthermore, if necessary, these may also be used in combination with an extender pigment.

[0044] Examples of the organic pigments include azo pigments, diazo pigments, azomethine pigments, methine pigments, anthraquinone pigments, phthalocyanine pigments, perinone pigments, perylene pigments, diketopyrrolopyrrole pigments, thioindigo pigments, iminoisoindoline pigments, isoindolinone pigments, dioxazine pigments, quinacridone pigments, flavanthrone pigments, indanthrone pigments, anthrapyrimidine pigments, carbazole pigments, monoarylide yellow, diarylide yellow, benzimidazolone yellow, tolyl orange, naphthol orange, and quinophthalone pigments.

[0045] Examples of the inorganic pigment include titanium dioxide, antimony trioxide, zinc oxide, lithopone, white lead, red iron oxide, black iron oxide, chromium oxide green, carbon black, yellow lead, molybdenum red, ferric ferrocyanide, ultramarine, lead chromate, etc. Examples of the inorganic pigment also include extender pigments such as mica, clay, aluminum powder, talc, aluminum silicate, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, and magnesium carbonate.

[0046] The pigment contained in the image forming layer is preferably a pigment that exhibits a hue other than white, such as a chromatic color or black.

[0047] From the viewpoint of dispersion stability and color development, the average particle size of the pigment is preferably 10 to 1,000 nm, more preferably 20 to 500 nm, even more preferably 40 to 200 nm, and still more preferably 50 to 100 nm.

[0048] The average particle size of the pigment can be measured by a laser diffraction / scattering particle size distribution analyzer or dynamic light scattering. For example, the cumulant average particle size measured by dynamic light scattering, as shown in the examples below, can be used. However, in cases where measurement by dynamic light scattering is difficult, such as in the case of black pigments, the 50% particle size in the volume-based particle size distribution measured by a laser diffraction / scattering particle size distribution analyzer can be used as the average particle size.

[0049] The content of the coloring material in the image forming layer is preferably from 1 to 50% by weight, more preferably from 10 to 30% by weight, and even more preferably from 10 to 25% by weight.

[0050] 2-2-2. Resin The image-forming layer preferably further contains a resin (hereinafter referred to as an image-forming resin). The image-forming resin may be used alone or in combination of two or more.

[0051] The type of image-forming resin is not particularly limited, and known resins used in inkjet printing can be used. Examples include vinyl resins, acrylic resins, polyester resins, olefin resins, urethane resins, fluorine-based resins, silicone resins, epoxy resins, phenoxy resins, phenolic resins, and xylene resins. Among these, at least one selected from the group consisting of acrylic resins, polyester resins, and urethane resins is preferred, and acrylic resins are particularly preferred.

[0052] The compositions of the acrylic resin, polyester resin, and urethane resin, including preferred embodiments thereof, can be directly applied to the compositions of the acrylic resin, polyester resin, and urethane resin in the white printed layer described below.

[0053] The image-forming resin is preferably a water-dispersible resin capable of forming an emulsion in water.

[0054] The glass transition temperature (Tg) of the image-forming resin is preferably −50 to 10° C., more preferably −45 to 5° C., and even more preferably −40 to 3° C. By adjusting the Tg of the image-forming resin to the above-mentioned lower limit or higher, it is possible to improve the coating strength, and by adjusting it to the above-mentioned upper limit or lower, it is possible to further suppress cracking of the image even under harsh conditions such as washing and tumble drying. In this specification, the Tg of the image-forming resin refers to the Tg of the resin used to form the image-forming layer; for example, when the image-forming resin has a crosslinked structure with a crosslinking agent described below, it refers to the Tg of the resin before crosslinking.

[0055] In this specification, the Tg of a resin can be determined by differential scanning calorimetry (DSC). When two or more resins are used or when the resin has a core-shell structure, multiple Tgs may be observed. In this case, it is preferable that at least one Tg satisfies the above range, and it is more preferable that all Tgs satisfies the above range.

[0056] The weight-average molecular weight (Mw) of the image-forming resin may be adjusted appropriately depending on the type of resin. From the viewpoint of suppressing the flow of the image-forming ink during printing, it is preferably 50,000 or more, more preferably 200,000 or more, and even more preferably 400,000 or more. Furthermore, from the viewpoint of film-forming ability and water resistance, the upper limit of the weight-average molecular weight of the image-forming resin is preferably 5,000,000 or less, and may be 3,000,000 or less, or 1,000,000 or less. That is, the Mw of the image-forming resin is preferably 50,000 to 5,000,000, more preferably 200,000 to 3,000,000, and even more preferably 400,000 to 1,000,000. In particular, when the image-forming resin is an acrylic resin, it is preferable to adjust the Mw within the above range. In this specification, the Mw of the image-forming resin refers to the Mw of the resin used to form the image-forming layer. For example, when the image-forming resin has a crosslinked structure with a crosslinking agent, as described below, it refers to the Mw of the resin before crosslinking.

[0057] In this specification, the weight average molecular weight (Mw) and number average molecular weight (Mn) of a resin can be calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC).

[0058] The image-forming resin may have a crosslinked structure crosslinked by a crosslinking agent. It is believed that the crosslinked structure of the image-forming resin allows for the formation of a tough image-forming layer, thereby further improving the durability (preferably washing and tumble drying fastness) of the transfer print. The content of the structure derived from the crosslinking agent is not particularly limited, but is, for example, 0 to 10% by mass, preferably 0.1 to 8% by mass, and more preferably 0.5 to 5% by mass, relative to 100% by mass of the image-forming resin.

[0059] As for the crosslinking agent capable of crosslinking the image-forming resin, the explanation of the crosslinking agent capable of crosslinking the resin for the white printing layer described later can be applied mutatis mutandis.

[0060] The content of the image-forming resin in the image-forming layer is, for example, 30 to 99% by mass, preferably 50 to 90% by mass, and more preferably 60 to 85% by mass. The total content of the colorant and the image-forming resin in the image-forming layer is, for example, 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass.

[0061] 2-2-3. Dispersant The image-forming layer may further contain one or more dispersants. A dispersant is preferably contained when a pigment is used as the colorant. This can improve the dispersion stability of the pigment. Dispersants that can be used in the image-forming layer are the same as those described in the section "2-3-3. Dispersant," including their preferred embodiments. The content of the dispersant is preferably 1 to 100 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the colorant (preferably the pigment).

[0062] 2-2-4. Surfactant The image-forming layer may further contain one or more surfactants. Surfactants that can be used in the image-forming layer are the same as those described in the section "2-3-4. Surfactant," including preferred embodiments thereof. The content of the surfactant in the image-forming layer is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %. The image-forming layer is a layer formed from an image-forming ink, which will be described later, and adjusting the amount of surfactant to fall within the above range improves the ejection stability of the image-forming ink.

[0063] The image-forming layer may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. For example, the image-forming layer may contain an appropriate amount of additives such as a leveling agent, an ultraviolet absorber, an ultraviolet stabilizer, a thickener, a wetting agent, a plasticizer, a stabilizer, an antifoaming agent, an antioxidant, a crosslinking accelerator, a pH adjuster, or a preservative.

[0064] 2-3. White Printed Layer The white printed layer contains a white pigment and a resin. The white printed layer serves as a base layer for the intended image, and the concealing properties of the white printed layer can enhance the color development of the image.

[0065] 2-3-1. White Pigment Known white pigments can be used as the white pigment contained in the white print layer, and examples include titanium dioxide, antimony trioxide, zinc oxide such as zinc white, lithopone, white lead, calcium carbonate, magnesium hydroxide, aluminum hydroxide, barium sulfate, magnesium carbonate, clay, talc, and aluminum silicate. These may be used alone or in combination of two or more. Among these, titanium dioxide is preferred from the viewpoint of having a high refractive index and excellent hiding power, and titanium dioxide having a rutile crystal structure is preferred.

[0066] From the viewpoint of achieving superior hiding power, the cumulant average particle size of the white pigment is preferably from 100 to 500 nm, more preferably from 150 to 450 nm, and even more preferably from 200 to 400 nm.

[0067] The content of the white pigment in the white printed layer is preferably from 20 to 80% by mass, and more preferably from 40 to 60% by mass.

[0068] 2-3-2. Resin Examples of the resin contained in the white printing layer (hereinafter sometimes referred to as the resin for the white printing layer) include, for example, vinyl resins, acrylic resins, polyester resins, olefin resins, urethane resins, fluorine-based resins, silicone resins, epoxy resins, phenoxy resins, phenolic resins, and xylene resins. Among these, at least one selected from the group consisting of acrylic resins, polyester resins, and urethane resins is preferred, with acrylic resins being particularly preferred. The total content of acrylic resins, polyester resins, and urethane resins (particularly the content of acrylic resins) in 100% by mass of the resin for the white printing layer is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and may even be 100% by mass.

[0069] The acrylic resin preferably contains a structural unit derived from a (meth)acrylic acid alkyl ester. Examples of the (meth)acrylic acid alkyl ester include (meth)acrylic acid chain alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, sec-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, 2-octyl (meth)acrylate, tridecyl (meth)acrylate, n-lauryl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate; and (meth)acrylic acid cyclic alkyl esters such as cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. The structural unit derived from the (meth)acrylic acid alkyl ester may be contained in the acrylic resin either alone or in combination of two or more.

[0070] Among the (meth)acrylic acid alkyl esters, (meth)acrylic acid alkyl esters having a homopolymer glass transition temperature (Tg) of −20° C. or lower (hereinafter, sometimes referred to as low Tg (meth)acrylic acid alkyl esters) and / or methacrylic acid C 1-5 The alkyl ester is preferred, and at least a low Tg (meth)acrylic acid alkyl ester is more preferred. By appropriately adjusting the content of structural units derived from these monomers, it becomes easy to adjust the Tg of the acrylic resin.

[0071] In this specification, the "glass transition temperature of a homopolymer" may be, for example, a value (when multiple Tg values ​​are listed, the lowest value) described in "POLYMER HANDBOOK THIRD EDITION" (by J. BRANDRUP and E. H. IMMERGUT, 1989, published by John Wiley & Sons, Inc., pp. VI / 209 to VI / 277). For compounds not described in "POLYMER HANDBOOK THIRD EDITION," a value (calculated value) determined by a computer using commercially available glass transition temperature calculation software (for example, "MATERIALS STUDIO" manufactured by Accelrys Software Inc., version: 4.0.0.0, module: Synthia, conditions: calculation with a weight average molecular weight of 100,000) may be used.

[0072] The Tg of the low Tg (meth)acrylic acid alkyl ester is −20° C. or lower, preferably −100 to −20° C., and more preferably −80 to −30° C. Among the low Tg (meth)acrylic acid alkyl esters, at least one selected from n-butyl acrylate, 2-octyl acrylate, and 2-ethylhexyl acrylate is preferred.

[0073] The methacrylic acid C 1-5 The alkyl ester refers to a compound in which the number of carbon atoms in the alkyl group constituting the methacrylic acid alkyl ester is 1 to 5. Among them, methacrylic acid C alkyl esters such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and tert-butyl methacrylate are particularly preferred. 1-4 Chain alkyl esters are preferred, and methyl methacrylate is more preferred.

[0074] It is also preferable to use a (meth)acrylic acid cyclic alkyl ester as the (meth)acrylic acid alkyl ester. Among the (meth)acrylic acid cyclic alkyl esters, at least one selected from cycloalkyl (meth)acrylate and isobornyl (meth)acrylate is preferred, and at least one selected from cyclohexyl (meth)acrylate and isobornyl (meth)acrylate is more preferred. The content of structural units derived from the (meth)acrylic acid cyclic alkyl ester in 100% by mass of the acrylic resin is, for example, 0 to 20% by mass, preferably 1 to 15% by mass, and more preferably 3 to 10% by mass.

[0075] The content of structural units derived from alkyl (meth)acrylate in 100% by mass of the acrylic resin is preferably 20 to 100% by mass, more preferably 30 to 90% by mass, and even more preferably 40 to 75% by mass.

[0076] The acrylic resin preferably has a structural unit derived from an acid group-containing monomer. By including a structural unit derived from an acid group-containing monomer in the acrylic resin, the stability of the acrylic resin improves, and the durability (preferably washing and tumble drying fastness) of the resulting transfer print tends to be further improved. The structural unit derived from the acid group-containing monomer may be contained in the acrylic resin alone or in two or more types.

[0077] The acid group-containing monomer may have at least one acid group and at least one polymerizable unsaturated group in the molecule. Examples of the acid group include a sulfo group and a carboxy group, with a carboxy group being preferred. The acid group may form a salt, and examples of the salt include an alkali metal salt and an ammonium salt. Examples of the alkali metal constituting the alkali metal salt include lithium, sodium, and potassium. The ammonium constituting the ammonium salt is NH4 +Examples of the organic ammonium include tetraalkylammonium such as tetramethylammonium and tetrabutylammonium, trialkylammonium such as trimethylammonium, triethylammonium and tributylammonium, hydroxyalkylammonium such as monoethanolammonium, diethanolammonium and triethanolammonium, and dialkylmonohydroxyalkylammonium such as dimethylmonoethanolammonium.

[0078] Specific examples of the acid group-containing monomer include unsaturated monocarboxylic acids or salts thereof, such as (meth)acrylic acid, cinnamic acid, and crotonic acid; unsaturated dicarboxylic acids or salts thereof, such as maleic acid, fumaric acid, itaconic acid, and citraconic acid; unsaturated dicarboxylic acid monoesters or salts thereof, such as maleic acid monomethyl ester, maleic acid monobutyl ester, itaconic acid monomethyl ester, and itaconic acid monobutyl ester; unsaturated dicarboxylic acid anhydrides, such as maleic anhydride; 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, and 2-acryloyloxyethyl hexahydrophthalic acid. Among these, the acid group-containing monomer is preferably an unsaturated monocarboxylic acid and / or a salt thereof, and more preferably (meth)acrylic acid and / or a salt thereof.

[0079] The content of structural units derived from acid group-containing monomers in 100% by mass of the acrylic resin is, for example, 0 to 8% by mass, preferably 0.1 to 5% by mass, more preferably 0.3 to 3% by mass, and even more preferably 0.5 to 2% by mass.

[0080] The acrylic resin preferably has a structural unit derived from a styrene-based monomer. The structural unit derived from a styrene-based monomer can further improve the water resistance of the transfer print. The acrylic resin may contain one type of structural unit derived from a styrene-based monomer alone, or two or more types of structural units derived from a styrene-based monomer.

[0081] Examples of the styrene-based monomer include styrene; C alkyl groups such as halogen atoms (e.g., fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms); and alkyl groups (e.g., methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, and tert-butyl groups). 1-4 alkyl group), vinyl group, alkoxysilyl group (e.g., tri-C such as trimethoxysilyl group, triethoxysilyl group, etc. 1-4 and styrene having one or more substituents such as a methyl group, an alkoxysilyl group, etc. The substituent is preferably a halogen atom and / or an alkyl group. Specific examples of the styrene-based monomer include styrene, α-methylstyrene, vinyltoluene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, divinylbenzene, p-styryltrimethoxysilane, and 2-styrylethyltrimethoxysilane. Among the styrene-based monomers, styrene is preferred from the viewpoint of further increasing water resistance.

[0082] The content of structural units derived from styrene-based monomers in 100% by mass of the acrylic resin is preferably 0 to 80% by mass, more preferably 10 to 70% by mass, and even more preferably 20 to 60% by mass.

[0083] The acrylic resin may further contain a structural unit derived from a hydroxyl group-containing monomer. The presence of the structural unit derived from a hydroxyl group-containing monomer can enhance the stability of emulsion particles during polymerization. The acrylic resin may contain one type of structural unit derived from a hydroxyl group-containing monomer alone, or two or more types of structural units derived from a hydroxyl group-containing monomer.

[0084] Examples of the hydroxyl group-containing monomer include (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. Among these, (meth)acrylic acid hydroxy C 2-4 Alkyl esters are preferred.

[0085] The content of structural units derived from hydroxyl group-containing monomers in 100% by mass of the acrylic resin is, for example, 0 to 8% by mass, preferably 0.1 to 5% by mass, more preferably 0.3 to 3% by mass, and even more preferably 0.5 to 2% by mass.

[0086] In particular, the acrylic resin contains a structural unit derived from a low Tg (meth)acrylic acid alkyl ester and a methacrylic acid C 1-5 Preferably, the copolymer further comprises a structural unit derived from an alkyl ester and / or a styrene-based monomer (particularly a structural unit derived from a styrene-based monomer) (Aspect A), and more preferably, in Aspect A, a structural unit derived from an acid group-containing monomer (Aspect B). Also preferably, in Aspects A and B, the copolymer further comprises a structural unit derived from a (meth)acrylic acid cyclic alkyl ester (Aspect C), or in Aspects A and B, the copolymer further comprises a structural unit derived from a hydroxyl group-containing monomer (Aspect D), and more preferably, in Aspects A and B, the copolymer further comprises a structural unit derived from a (meth)acrylic acid cyclic alkyl ester and a structural unit derived from a hydroxyl group-containing monomer (Aspect E).

[0087] Low Tg (meth)acrylic acid alkyl ester, methacrylic acid C in 100% by mass of acrylic resin 1-5 The total content of structural units derived from alkyl esters, styrene-based monomers, and acid group-containing monomers is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 93% by mass or more, and may be 100% by mass. The content of structural units derived from low Tg (meth)acrylic acid alkyl esters in 100% by mass of acrylic resin may be adjusted appropriately depending on the target Tg, but is preferably 20 to 95% by mass, more preferably 30 to 85% by mass, and even more preferably 40 to 70% by mass. Methacrylic acid C 1-5The total content of structural units derived from alkyl esters and styrene-based monomers is preferably 10 to 350 parts by mass, more preferably 25 to 200 parts by mass, even more preferably 40 to 100 parts by mass, and still more preferably 40 to 80 parts by mass, relative to 100 parts by mass of structural units derived from low Tg (meth)acrylic acid alkyl esters. 1-5 For example, it is 0 to 8 parts by mass, preferably 0.1 to 5.0 parts by mass, more preferably 0.3 to 3.0 parts by mass, and even more preferably 0.5 to 2.5 parts by mass, relative to 100 parts by mass of the total of the structural units derived from the alkyl ester and the styrene-based monomer.

[0088] The acrylic resin may have a structural unit derived from a monomer other than a (meth)acrylic acid alkyl ester, an acid group-containing monomer, a styrene-based monomer, and a hydroxyl group-containing monomer. The other monomer is not particularly limited, and examples thereof include (meth)acrylic acid alkyl esters, (meth)acrylic acid hydroxyalkyl esters, and (meth)acrylic acid hydroxyalkyl esters such as alkoxyalkyl group-containing (meth)acrylates (e.g., methoxyethyl (meth)acrylate, methoxybutyl (meth)acrylate), and piperidine group-containing (meth)acrylates (e.g., 4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine, 4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine); 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazolidinyl; Examples of the structural unit derived from the other monomer include addition-polymerizable oxazolines such as vinyl acetate, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline; vinyl monomers such as vinyl acetate, vinyl chloride, and vinyl benzoate; acrylonitrile; (meth)acrylamide monomers such as (meth)acrylamide, N-monomethyl(meth)acrylamide, N-monoethyl(meth)acrylamide, and N,N-dimethyl(meth)acrylamide; and olefin monomers such as ethylene and propylene. The structural unit derived from the other monomer may be contained in the acrylic resin singly or in combination of two or more types.

[0089] The content of structural units derived from other monomers in 100% by mass of the acrylic resin is preferably 40% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may be 0% by mass.

[0090] The acrylic resin may be a commercially available product or may be synthesized as appropriate. When the acrylic resin is obtained by synthesis, it can be produced by a conventionally known polymerization method, for example, a solution polymerization method, a bulk polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. Among these, an emulsion polymerization method is preferred, that is, a method in which a monomer component (at least one selected from (meth)acrylic acid alkyl ester, acid group-containing monomer, styrene-based monomer, hydroxyl group-containing monomer, and other monomer) that becomes a structural unit of the acrylic resin is emulsion polymerized in an aqueous solvent (specifically, water or water and a water-soluble organic solvent) in the presence of an emulsifier and a polymerization initiator is preferably mentioned. The specific means and conditions for polymerization may be appropriately selected and adopted from conventionally known means and techniques.

[0091] In order to adjust the weight-average molecular weight of the resulting resin, the polymerization reaction may be carried out in the presence of a chain transfer agent. Examples of chain transfer agents include 2-ethylhexyl thioglycolate, tert-dodecyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, α-methylstyrene, and α-methylstyrene dimer. These chain transfer agents may be used alone or in combination of two or more. The amount of chain transfer agent used may be adjusted appropriately depending on the target weight-average molecular weight, but is preferably 0.01 to 5 parts by mass, and more preferably 0.03 to 1 part by mass, per 100 parts by mass of the monomer components.

[0092] The polyester resin is not particularly limited as long as it is a polymer having an ester bond in the main chain, and known polyester resins can be used. As the polyester resin, an appropriately synthesized product or a commercially available product can be used.

[0093] The polyester resin is preferably a condensation polymer of an aromatic dicarboxylic acid and a diol compound.

[0094] Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, and terephthalic acid.

[0095] Examples of the diol compound include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, and neopentyl glycol; aromatic alcohols such as alkylene oxide adducts of bisphenol A, such as polyoxypropylene-2,2-bis(4-hydroxyphenyl)propane and polyoxyethylene-2,2-bis(4-hydroxyphenyl)propane; and hydrogenated bisphenol A or alkylene oxide adducts thereof.

[0096] An aliphatic polybasic acid may be added to the polyester resin for the purpose of improving fluidity. Examples of the aliphatic polybasic acid include saturated aliphatic dicarboxylic acids or anhydrides thereof, such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids or anhydrides thereof, such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, and citraconic anhydride; and tri- or higher functional aliphatic carboxylic acids, such as 1,2,3,4-butanetetracarboxylic acid.

[0097] The urethane resin is not particularly limited as long as it is a resin having a urethane skeleton, and known urethane resins can be used, such as a reaction product of polyisocyanate and polyol. As the urethane resin, an appropriately synthesized product or a commercially available product may be used. When the urethane resin is obtained by synthesis, the reaction of polyisocyanate and polyol can be carried out by a known method.

[0098] The polyisocyanate is a compound containing at least two isocyanate groups in the molecule. Examples of the polyisocyanate include chain aliphatic isocyanates such as tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; aliphatic isocyanates having a cyclic structure such as 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate; 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m- Examples of the isocyanate include aromatic isocyanates such as phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate; modified products thereof such as isocyanurates and biuret products; and the like. Also usable are so-called blocked isocyanates in which the isocyanate groups in these polyisocyanates are inactivated by reacting them with a masking agent having active hydrogen. These polyisocyanates may be used alone or in combination of two or more.

[0099] Examples of the polyol include polyether polyols and polycarbonate polyols. Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of the polycarbonate polyol include reaction products of diols (preferably (poly)alkylene glycols) such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol with phosgene, dialkyl carbonates such as dimethyl carbonate, or cyclic carbonates such as ethylene carbonate. These polyols may be used alone or in combination of two or more.

[0100] Furthermore, an acrylic urethane resin may be used as the urethane resin. In this specification, a resin having a urethane skeleton is classified as a urethane resin, that is, an acrylic urethane resin is classified as a urethane resin rather than an acrylic resin.

[0101] Examples of acrylic urethane resins include copolymers of acrylic resins and urethane resins. More specifically, examples include copolymers in which a urethane prepolymer and a (meth)acrylic monomer are polymerized to introduce structural units derived from the (meth)acrylic monomer or side chains of a poly(meth)acrylic structure into the urethane skeleton. Examples of urethane prepolymers include those synthesized using the above-mentioned polyisocyanates and polyols. Examples of (meth)acrylic monomers include, but are not limited to, (meth)acrylic acid alkyl esters, (meth)acrylic acid, hydroxyalkyl (meth)acrylates, etc., which have been described as monomers constituting acrylic resins.

[0102] The resin for the white print layer is preferably a water-dispersible resin that can form an emulsion in water.

[0103] The glass transition temperature (Tg) of the resin for the white printing layer is preferably −50 to 10° C., more preferably −45 to 5° C., and even more preferably −40 to 3° C. Adjusting the Tg of the resin for the white printing layer to be equal to or greater than the lower limit described above can improve the coating strength, while adjusting it to be equal to or less than the upper limit described above can further suppress image cracking, even under harsh conditions such as washing and tumble drying. In this specification, the Tg of the resin for the white printing layer refers to the Tg of the resin used to form the white printing layer. For example, if the resin for the white printing layer has a crosslinked structure with a crosslinking agent described below, it refers to the Tg of the resin before crosslinking.

[0104] The weight-average molecular weight (Mw) of the resin for the white printing layer can be adjusted appropriately depending on the type of resin. However, from the viewpoint of suppressing flow of the white ink during printing, it is preferably 50,000 or more, more preferably 200,000 or more, and even more preferably 400,000 or more. Furthermore, from the viewpoint of film-forming ability and water resistance, the upper limit of the weight-average molecular weight of the resin for the white printing layer is preferably 5,000,000 or less, and may be 3,000,000 or less, or 1,000,000 or less. That is, the Mw of the resin for the white printing layer is preferably 50,000 to 5,000,000, more preferably 200,000 to 3,000,000, and even more preferably 400,000 to 1,000,000. In particular, when the resin for the white printing layer is an acrylic resin, it is preferable to adjust the Mw within the above range. In this specification, the Mw of the resin for the white printing layer refers to the Mw of the resin used to form the white printing layer. For example, if the resin for the white printing layer has a crosslinked structure with a crosslinking agent as described below, it refers to the Mw of the resin before crosslinking.

[0105] The resin for the white printing layer may have a crosslinked structure crosslinked by a crosslinking agent. It is presumed that the resin for the white printing layer having a crosslinked structure can form a strong white printing layer, thereby further improving the durability (preferably washing and tumble drying fastness) of the transfer print.

[0106] Examples of the crosslinking agent include an isocyanate compound, an epoxy compound, a melamine compound, a metal chelate compound, an aziridine compound, a mercapto compound, and an oxazoline compound, and preferably an oxazoline compound. The crosslinking agent may be used alone or in combination of two or more.

[0107] The oxazoline compound as the crosslinking agent means a compound having two or more oxazoline groups in the molecule. Examples of the oxazoline compound include 2,2'-bis(2-oxazoline), 2,2'-methylene-bis(2-oxazoline), 2,2'-ethylene-bis(2-oxazoline), 2,2'-trimethylene-bis(2-oxazoline), 2,2'-tetramethylene-bis(2-oxazoline), 2,2'-hexamethylene-bis(2-oxazoline), 2,2'-octamethylene-bis(2-oxazoline), and 2,2'-ethylene-bis(4 ,4'-dimethyl-2-oxazoline), 2,2'-p-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(2-oxazoline), 2,2'-m-phenylene-bis(4,4'-dimethyl-2-oxazoline), bis(2-oxazolinylcyclohexane) sulfide, bis(2-oxazolinylnorbornane) sulfide, oxazoline group-containing polymers, and the like are not limited to these examples.

[0108] Among the above oxazoline compounds, water-soluble oxazoline compounds are preferred from the viewpoint of excellent crosslinking performance, and oxazoline group-containing polymers are also preferred. The above oxazoline group-containing polymers can be produced by a conventionally known production method. For example, a method of polymerizing one or more addition-polymerizable oxazolines, or a monomer component including an addition-polymerizable oxazoline and a monomer copolymerizable with the addition-polymerizable oxazoline, can be mentioned.

[0109] Examples of the addition-polymerizable oxazoline include compounds having a polymerizable unsaturated group and an oxazoline group in the molecule, such as 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. Furthermore, the copolymerizable monomer is preferably a monomer that does not have a functional group that reacts with the oxazoline group and is copolymerizable with the addition-polymerizable oxazoline. For example, (meth)acrylic monomers such as (meth)acrylic acid alkyl esters; styrene-based monomers such as styrene, α-methylstyrene, and chloromethylstyrene; vinyl-based monomers such as vinyl acetate, vinyl chloride, and vinyl benzoate; acrylonitrile; (meth)acrylamide-based monomers such as acrylamide; and olefin-based monomers such as ethylene and propylene.

[0110] Among the oxazoline group-containing polymers, water-soluble oxazoline group-containing polymers are preferred, and can be produced by the same method as the above-mentioned method for producing the oxazoline group-containing polymer. Examples of the water-soluble oxazoline group-containing polymer include polymers having an acrylic resin or the like as a main chain and containing oxazoline groups in side chains.

[0111] Commercially available oxazoline group-containing polymers can also be used. Examples include water-soluble polymers such as EPOCROS WS-500 and EPOCROS WS-700, manufactured by Nippon Shokubai Co., Ltd., and emulsion polymers such as EPOCROS K-2010, EPOCROS K-2020, and EPOCROS K-2030. Of these, water-soluble polymers such as EPOCROS WS-500 and EPOCROS WS-700, manufactured by Nippon Shokubai Co., Ltd., are preferred.

[0112] The content of the structure derived from the crosslinking agent is not particularly limited, but is, for example, 0 to 10 mass %, preferably 0.1 to 8 mass %, and more preferably 0.5 to 5 mass %, relative to 100 mass % of the resin for the white printing layer.

[0113] The white print layer may contain one type of resin alone or two or more types of resins for the white print layer.

[0114] The content of the resin for the white printing layer in the white printing layer is, for example, 20 to 80% by mass, preferably 40 to 60% by mass. The total content of the white pigment and the resin for the white printing layer in the white printing layer is, for example, 50% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, and may be 100% by mass.

[0115] 2-3-3. Dispersant The white printed layer may further contain one or more dispersants. The inclusion of a dispersant can enhance the dispersion stability of the white pigment. Examples of dispersants that can be used in the white printed layer include poly(meth)acrylic acid (salts) such as poly(meth)acrylic acid and poly(meth)acrylate salts; copolymers of (meth)acrylic acid (salts) with one or more of the monomer components other than (meth)acrylic acid (salts), such as (meth)acrylic acid alkyl esters, (meth)acrylamide, styrene, maleic acid, maleic anhydride, maleic esters, and vinyl acetate; polyvinyl alcohol; and polyvinylpyrrolidone. The content of the dispersant is preferably 0.1 to 100 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the white pigment.

[0116] The white printed layer may further contain one or more surfactants. Preferred surfactants include, for example, acetylene glycol surfactants, silicone surfactants, and fluorine surfactants.

[0117] As the acetylene glycol surfactant, commercially available products may be used, and specific examples thereof include the Surfynol series (manufactured by Evonik Corporation), the Olfine series (manufactured by Nissin Chemical Industry Co., Ltd.), and the Acetylenol series (manufactured by Kawaken Fine Chemicals Co., Ltd.). As the silicone surfactant, a polyether-modified silicone surfactant is preferably used. As the silicone surfactant, commercially available products may be used, and specific examples thereof include the Silface series (manufactured by Nissin Chemical Industry Co., Ltd.), the KF series (manufactured by Nissin Chemical Industry Co., Ltd.), and BYK-345, 347, 348, 349, 3450, 3451, 3455, and 3480 (all manufactured by BYK). As the fluorine-based surfactant, for example, perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group on the side chain may be used. As the fluorine-based surfactant, commercially available products may be used, and specific examples include the Surflon series (manufactured by AGC Sei Chemical Co., Ltd.) and the Megafac F series (manufactured by DIC Corporation).

[0118] The surfactant is preferably an acetylene glycol surfactant or a silicone surfactant, more preferably a silicone surfactant, and even more preferably a polyether-modified silicone surfactant.

[0119] The white print layer is a layer formed from a white ink, which will be described later, and when the white ink contains two or more surfactants, it becomes easy to adjust the static surface tension of the white ink to a value suitable for inkjet ejection.

[0120] When two or more surfactants are used, it is preferable to use a silicone surfactant and an acetylene glycol surfactant in combination, and it is more preferable to use a polyether-modified silicone surfactant and an acetylene glycol surfactant in combination, which improves the ejection stability of the ink.

[0121] When a silicone surfactant and an acetylene glycol surfactant are used in combination, the mass ratio thereof (silicone surfactant / acetylene glycol surfactant) is preferably 0.1 to 20, more preferably 0.2 to 10, even more preferably 0.5 to 4.5, particularly preferably 0.7 to 3.0, and most preferably 1.0 to 2.0. In particular, it is preferable to adjust the mass ratio of the polyether-modified silicone surfactant to the acetylene glycol surfactant (polyether-modified silicone surfactant / acetylene glycol surfactant) to be within the above range.

[0122] The content of the surfactant in the white printed layer is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %. The white printed layer is a layer formed from a white ink, which will be described later, and by adjusting the amount of surfactant so that it falls within the above range, the ejection stability of the white ink can be improved.

[0123] The white print layer may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. For example, the white print layer may contain an appropriate amount of additives such as a leveling agent, an ultraviolet absorber, an ultraviolet stabilizer, a thickener, a wetting agent, a plasticizer, a stabilizer, an antifoaming agent, an antioxidant, a crosslinking accelerator, a pH adjuster, or a preservative.

[0124] 2-4. Adhesive Layer The adhesive layer contains an adhesive resin and serves to adhere the image to the medium upon transfer printing.

[0125] 2-4-1. Adhesive Resin Examples of adhesive resins include vinyl resins, acrylic resins, polyester resins, olefin resins, urethane resins, fluorine-based resins, silicone resins, epoxy resins, phenoxy resins, phenolic resins, and xylene resins, and among these, at least one selected from the group consisting of acrylic resins, polyester resins, and urethane resins is preferred. The total content of the acrylic resins, polyester resins, and urethane resins in 100% by mass of the adhesive resin is preferably 50% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and may even be 100% by mass.

[0126] In particular, it is preferable that the adhesive resin be a resin of the same type as the resin for the white printing layer. For example, when an acrylic resin is used as the resin for the white printing layer, it is preferable that an acrylic resin is also used as the adhesive resin; when a polyester resin is used as the resin for the white printing layer, it is preferable that a polyester resin is also used as the adhesive resin; or when a urethane resin is used as the resin for the white printing layer, it is preferable that a urethane resin is also used as the adhesive resin. By adopting such a configuration, the interface between the white printing layer and the adhesive layer in the transfer sheet or transfer print is less likely to peel, thereby further improving the transferability and the durability (preferably washing and tumble drying fastness) of the resulting transfer print.

[0127] The adhesive resin more preferably contains an acrylic resin. By including an acrylic resin, yellowing of the adhesive layer due to heating during the production of the transfer sheet or transfer print can be suppressed, which is advantageous in improving the design of the resulting transfer print. The content of the acrylic resin is, for example, 40% by mass or more, preferably 65% ​​by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass, based on 100% by mass of the total adhesive resin.

[0128] The acrylic resin preferably contains a structural unit derived from a (meth)acrylic acid alkyl ester. The structural unit derived from a (meth)acrylic acid alkyl ester may be contained in the acrylic resin alone or in two or more types. The description of the (meth)acrylic acid alkyl ester in the resin for the white printing layer, including preferred embodiments thereof, can be applied mutatis mutandis to the (meth)acrylic acid alkyl ester. The content of the structural unit derived from a (meth)acrylic acid alkyl ester in 100% by mass of the acrylic resin is preferably 20 to 100% by mass, more preferably 50 to 99.5% by mass, and even more preferably 70 to 99% by mass.

[0129] The acrylic resin preferably has a structural unit derived from an acid group-containing monomer. By including a structural unit derived from an acid group-containing monomer in the acrylic resin, the stability of the acrylic resin improves and the durability (preferably the washing and tumble drying fastness) of the resulting transfer print tends to be further improved. The structural unit derived from the acid group-containing monomer may be contained in the acrylic resin alone or in combination with two or more different types. The acid group-containing monomer, including its preferred embodiments, can be similarly described for the acid group-containing monomer in the resin for the white printing layer. The content of the structural unit derived from the acid group-containing monomer in 100% by mass of the acrylic resin is, for example, 0 to 8% by mass, preferably 0.1 to 5% by mass, and more preferably 0.5 to 3% by mass.

[0130] The acrylic resin may have a structural unit derived from a styrene-based monomer. The presence of a structural unit derived from a styrene-based monomer can further enhance the water resistance of the transfer print. The structural unit derived from a styrene-based monomer may be contained in the acrylic resin alone, or two or more types may be contained. The description of the styrene-based monomer in the resin for the white printing layer, including its preferred embodiments, can be applied mutatis mutandis to the styrene-based monomer. The content of the structural unit derived from a styrene-based monomer in 100% by mass of the acrylic resin is preferably 0 to 80% by mass, and may be 5 to 50% by mass or 10 to 30% by mass.

[0131] The acrylic resin may further contain a structural unit derived from a hydroxyl group-containing monomer. The presence of a structural unit derived from a hydroxyl group-containing monomer can enhance the stability of emulsion particles during polymerization. The acrylic resin may contain one type of structural unit derived from a hydroxyl group-containing monomer, or two or more types. The same description of the hydroxyl group-containing monomer in the resin for the white printing layer, including preferred embodiments thereof, can be applied to the hydroxyl group-containing monomer.

[0132] The content of structural units derived from hydroxyl group-containing monomers in 100% by mass of the acrylic resin is, for example, 0 to 8% by mass, preferably 0 to 5% by mass, and more preferably 0 to 3% by mass.

[0133] In particular, the acrylic resin contains a structural unit derived from a low Tg (meth)acrylic acid alkyl ester and a methacrylic acid C 1-5 It is preferable that the acrylic resin contains a structural unit derived from an alkyl ester and / or a styrene-based monomer, and more preferable that the acrylic resin further contains a structural unit derived from an acid group-containing monomer. 1-5 The total content of structural units derived from alkyl esters, styrene-based monomers, and acid group-containing monomers is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, particularly preferably 95% by mass or more, and may even be 100% by mass. The content of structural units derived from low Tg (meth)acrylic acid alkyl esters in 100% by mass of acrylic resin may be adjusted appropriately depending on the target Tg, but is preferably 20 to 95% by mass, more preferably 30 to 80% by mass, and even more preferably 40 to 60% by mass. Methacrylic acid C 1-5 The total content of structural units derived from alkyl esters and styrene-based monomers is preferably 10 to 350 parts by mass, more preferably 50 to 200 parts by mass, and even more preferably 80 to 150 parts by mass, per 100 parts by mass of structural units derived from low-Tg (meth)acrylic acid alkyl esters. 1-5The amount is, for example, 0 to 8 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the total of the structural units derived from the alkyl ester and the styrene-based monomer.

[0134] The acrylic resin may have structural units derived from other monomers other than (meth)acrylic acid alkyl esters, acid group-containing monomers, styrene-based monomers, and hydroxyl group-containing monomers. Examples of the other monomers include the monomers exemplified as other monomers in the resin for the white printing layer. The structural units derived from other monomers may be contained in the acrylic resin singly or in combination of two or more types. The content of the structural units derived from other monomers in 100% by mass of the acrylic resin is preferably 40% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may even be 0% by mass.

[0135] As with the acrylic resin for the white print layer, a commercially available product may be used as the acrylic resin, or a product synthesized as appropriate.

[0136] The composition of the polyester resin, including its preferred embodiments, can be the same as that of the polyester resin for the white print layer.

[0137] The composition of the urethane resin, including its preferred embodiments, can be the same as that of the urethane resin for the white print layer.

[0138] The glass transition temperature (Tg) of the adhesive resin is preferably −50 to 35°C, more preferably −25 to 20°C, and even more preferably −10 to 10°C. Transfer sheets are sometimes wound up and stored in roll form, and in this case, blocking due to the adhesive layer can become a problem. Having a Tg of the adhesive resin equal to or greater than the lower limit described above can suppress such blocking. Furthermore, having a Tg of the adhesive resin equal to or less than the upper limit described above can quickly soften the resin during transfer printing, improving transferability and, when the transfer medium is fabric, improving the texture of the resulting printed matter. In this specification, the Tg of the adhesive resin refers to the Tg of the resin used to form the adhesive layer. For example, if the adhesive resin has a crosslinked structure with a crosslinking agent, as described below, it refers to the Tg of the resin before crosslinking.

[0139] From the viewpoint of adjusting the balance between strength and flexibility of the entire printing layer, the Tg of the adhesive resin is preferably higher than the Tg of the white printing resin, and is preferably 5 to 40°C higher, and more preferably 10 to 30°C higher, than the Tg of the white printing resin.

[0140] The weight-average molecular weight (Mw) of the adhesive resin is, for example, 5,000 to 700,000, preferably 20,000 to 650,000, and more preferably 30,000 to 550,000, from the viewpoint of suppressing flow of the adhesive ink during printing. Durability (preferably washing and tumble drying fastness) can be further improved by adjusting the Mw of the adhesive resin to equal to or greater than the lower limit, while transferability can be further improved by adjusting the Mw of the adhesive resin to equal to or less than the upper limit. In particular, for acrylic resins, it is preferable to adjust the Mw to within the above range. In this specification, the Mw of the adhesive resin refers to the Mw of the resin used to form the adhesive layer. For example, if the adhesive resin has a crosslinked structure with a crosslinking agent, as described below, it refers to the Mw of the resin before crosslinking.

[0141] From the viewpoint of increasing the interfacial strength between the white printing layer and the adhesive layer, the Mw of the adhesive resin is preferably smaller than the Mw of the white printing resin, and is preferably 10,000 to 1,000,000 smaller, and more preferably 20,000 to 700,000 smaller, than the Mw of the white printing resin.

[0142] The molecular weight distribution of the adhesive resin is not particularly limited and may be 3 to 20. In particular, from the viewpoint of achieving a better balance between transferability and durability (particularly, fastness to washing and tumble drying), the molecular weight distribution is preferably 4 to 12, more preferably 4 to 10, and even more preferably 5 to 8. The molecular weight distribution is expressed as the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn). In this specification, the molecular weight distribution of the adhesive resin refers to the molecular weight distribution of the resin used to form the adhesive layer; for example, in the case where the adhesive resin has a crosslinked structure with a crosslinking agent described below, the molecular weight distribution refers to the molecular weight distribution of the resin before crosslinking.

[0143] The adhesive resin may have a crosslinked structure formed by crosslinking with a crosslinking agent. It is presumed that the crosslinked structure of the adhesive resin allows for the formation of a strong adhesive layer, thereby further improving the durability (preferably washing and tumble drying fastness) of the transfer print.

[0144] The type of crosslinking agent, including preferred embodiments thereof, can be the same as that described for the crosslinking agent in the resin for the white printing layer. The content of the structure derived from the crosslinking agent is not particularly limited, but is, for example, 0 to 10% by mass, preferably 0.1 to 8% by mass, and more preferably 0.5 to 5% by mass, relative to 100% by mass of the adhesive resin.

[0145] The adhesive layer may contain one type of adhesive resin alone or two or more types of adhesive resins.

[0146] The adhesive resin content in the adhesive layer is, for example, 60 to 100% by mass, preferably 80 to 99.5% by mass, and more preferably 90 to 99% by mass.

[0147] The adhesive layer may further contain one or more surfactants. Surfactants that can be used in the adhesive layer are the same as those described in the section "2-3-4. Surfactants," including preferred embodiments thereof.

[0148] The content of the surfactant in the adhesive layer is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %. The adhesive layer is a layer formed from an adhesive ink described below, and adjusting the amount of the surfactant so that it falls within the above range improves the ejection stability of the adhesive ink.

[0149] The adhesive layer may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. For example, the adhesive layer may contain an appropriate amount of additives such as a leveling agent, a dispersant, an ultraviolet absorber, an ultraviolet stabilizer, a thickener, a wetting agent, a plasticizer, a stabilizer, an antifoaming agent, an antioxidant, a crosslinking accelerator, a pH adjuster, or a preservative.

[0150] 3. Method for Manufacturing Transfer Sheet The transfer sheet of the present disclosure can be manufactured by performing the following steps in this order: a step of inkjet printing by ejecting an image-forming ink onto the ink-receiving layer-forming surface of a transfer substrate having an inkjet ink-receiving layer (hereinafter sometimes referred to as step 1); a step of inkjet printing by ejecting a white ink containing a white pigment and a resin onto the surface printed with the image-forming ink (hereinafter sometimes referred to as step 2); and a step of inkjet printing by ejecting an adhesive ink containing an adhesive resin onto the surface printed with the white ink (hereinafter sometimes referred to as step 3); and by setting the film thickness A of the white printing layer formed from the white ink to 5 to 35 μm, the film thickness B of the adhesive layer formed from the adhesive ink to 5 to 50 μm, and the thickness C of the transfer sheet to 25 to 200 μm.

[0151] 3-1. Step 1 Step 1 is a step of inkjet printing by ejecting an image-forming ink onto the ink-receiving layer-forming surface of a transfer substrate. The configuration of the transfer substrate used in Step 1 can be the same as that described in "2-1. Transfer substrate," including preferred embodiments thereof.

[0152] The image-forming ink used in step 1 typically contains one or more colorants. The description of "2-2-1. Colorant" can be applied mutatis mutandis to the colorants contained in the image-forming ink, including preferred embodiments thereof. The content of the colorant in the solid content of the image-forming ink is preferably 1 to 50% by mass, more preferably 10 to 30% by mass, and even more preferably 10 to 25% by mass.

[0153] The image-forming ink preferably further contains one or more resins. The same explanation as in "2-2-2. Resin" can be applied mutatis mutandis to the resin contained in the image-forming ink, except that the resin preferably does not have a crosslinked structure formed by a crosslinking agent.

[0154] When the resin is added to the image-forming ink, it is preferably added as an emulsion; that is, the resin is preferably contained in the image-forming ink as emulsion particles. The shape of the emulsion particles is not particularly limited, but they are typically spherical. The shape can be measured using a transmission electron microscope or a scanning electron microscope. The emulsion particles may be resin particles having a single-phase structure or a multi-phase structure (preferably a core-shell structure). The average particle diameter of the emulsion particles is, for example, 30 to 500 nm, preferably 80 to 300 nm, more preferably 100 to 300 nm, and even more preferably 150 to 250 nm. Adjusting the average particle diameter of the emulsion particles within the above range facilitates blending a high concentration of emulsion particles while maintaining the viscosity of the image-forming ink within an appropriate range. The average particle diameter of the emulsion particles can be determined by the cumulant average particle diameter measured by dynamic light scattering, as shown in the examples below.

[0155] The resin content in the solid content of the image forming ink is, for example, 30 to 99% by mass, preferably 50 to 90% by mass, and more preferably 60 to 85% by mass.

[0156] The image-forming ink may further contain one or more crosslinking agents. By including a crosslinking agent in the image-forming ink together with a resin, a crosslinked structure is formed during the drying process or transfer printing described below, while maintaining film-forming properties during printing, allowing for the formation of a tough image-forming layer. The description of the crosslinking agent in "2-2-2. Resin" can be applied mutatis mutandis to the crosslinking agent contained in the image-forming ink, including preferred embodiments thereof. The content of the crosslinking agent in the image-forming ink is not particularly limited, but is, for example, 0 to 10 parts by mass, preferably 0.1 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass, relative to 100 parts by mass of the resin in the image-forming ink.

[0157] The image-forming ink may further contain one or more dispersants. The description of "2-2-3. Dispersant" can be applied mutatis mutandis to the dispersants contained in the image-forming ink, including preferred embodiments thereof. The content of the dispersant is preferably 1 to 100 parts by mass, more preferably 10 to 50 parts by mass, per 100 parts by mass of the colorant (preferably pigment).

[0158] The image-forming ink may further contain a surfactant. The surfactant contained in the image-forming ink, including its preferred embodiments, can be described mutatis mutandis in "2-2-4. Surfactant." The surfactant content in the solid content of the image-forming ink is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %.

[0159] The image-forming ink preferably further contains one or more solvents. The solvent acts as a diluent to adjust the viscosity of the image-forming ink. The solvent contained in the image-forming ink, including preferred embodiments thereof, can be the same as the solvent contained in the white ink described below.

[0160] The content of the solvent in the image-forming ink may be set according to the desired viscosity of the image-forming ink, and is not particularly limited, but is, for example, 40 to 90% by mass, preferably 50 to 88% by mass, and more preferably 55 to 85% by mass.

[0161] The image-forming ink may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. The explanation of "2-2-5. Additives" can be applied mutatis mutandis to the additives contained in the image-forming ink.

[0162] The viscosity of the image-forming ink at 25°C is preferably 2 to 10 mPa·s, and more preferably 3 to 7 mPa·s. By adjusting the viscosity of the image-forming ink to the above lower limit or more, it is possible to reduce ink drying unevenness, and by adjusting the viscosity to the above upper limit or less, it is possible to impart inkjet ejection stability. The viscosity of each ink can be measured using an E-type viscometer.

[0163] An inkjet recording apparatus can be used as an apparatus for performing the inkjet printing in step 1. When an inkjet recording apparatus is used, the image-forming ink can be printed on the transfer substrate by ejecting the image-forming ink from an inkjet head and depositing the image-forming ink on a predetermined portion of the transfer substrate.

[0164] It should be noted that by using an inkjet recording apparatus equipped with a plurality of inkjet heads, it is possible to continuously carry out steps 1 and 2 or steps 1 and 3. For example, by installing an ink set containing an image-forming ink, a white ink, and an adhesive ink in each color ink cartridge of the inkjet recording apparatus, and ejecting ink from each inkjet head corresponding to each ink cartridge, it is possible to continuously carry out steps 1 to 3.

[0165] The number of times the image-forming ink is printed is not particularly limited and may be, for example, 1 to 6 times, preferably 1 to 4 times. When printing is performed multiple times, the image-forming ink used in each printing may be the same or different. Furthermore, the amount of ink ejected in each printing is not particularly limited and may be determined depending on the desired thickness of the image-forming layer.

[0166] In step 1, if necessary, a drying treatment (hereinafter referred to as drying treatment 1) may be carried out to evaporate some or all of the components of the printed image-forming ink excluding the solid content (i.e., the solvent). In the transfer substrate of the present disclosure, an ink-receiving layer is provided on the surface printed with the image-forming ink, and when white ink is further printed thereon, the image-forming ink may flow, making it difficult to obtain a clear image, so it is preferable to carry out drying treatment 1.

[0167] In drying process 1, of the 100% by mass of the components of the image-forming ink excluding solids, preferably 10 to 80% by mass, more preferably 15 to 70% by mass, even more preferably 20 to 60% by mass, and particularly preferably 20 to 50% by mass or 20 to 40% by mass is evaporated. Adjusting the evaporation amount to above the lower limit can suppress flow of the white ink in process 2, described below. Adjusting the evaporation amount to below the upper limit can suppress peeling at the interface between the image-forming layer and the white printing layer during transfer printing, thereby further improving transferability. The evaporation amount can be calculated by ejecting a certain mass of ink onto a substrate using an ink with a known solids concentration, and then measuring the total mass of the ink and substrate and the mass of the substrate alone after drying using a precision balance. Drying conditions that result in the desired evaporation amount are then determined, and the drying process is carried out under those conditions.

[0168] The device for performing the drying process 1 is not particularly limited, but for example, a heating means (e.g., a platen heater, a hot air heater, an infrared heater) in an inkjet recording apparatus can be used. Among these, it is preferable to use a platen heater from the viewpoint of uniform drying. If the inkjet recording apparatus does not have a platen heater, a planar heating element such as a rubber heater can be installed on the platen of the inkjet recording apparatus as an alternative to the platen heater.

[0169] The evaporation amount can be adjusted by controlling the heating temperature, heating time, hot air temperature, air volume, etc. It is preferable to set the conditions of the heater by measuring the evaporation amount in advance before an experiment. For example, when using a platen heater or a planar heating element as an alternative thereto, the image-forming ink can be dried by heating the backside of the transfer substrate with the platen heater or planar heating element. The heating temperature of the platen heater or planar heating element is preferably 30 to 80°C, more preferably 40 to 70°C, and even more preferably 40 to 60°C. Adjusting the heating temperature to above the lower limit can shorten the heating time, while adjusting the heating temperature to below the upper limit can prevent nozzle clogging due to heat transfer to the inkjet head.

[0170] The drying process 1 may be carried out simultaneously with the printing of the ink, after the printing of the ink, or both simultaneously with the printing of the ink and after the printing. When the drying process 1 is carried out simultaneously with the printing of the ink, it may be carried out continuously from the start to the end of printing or may be carried out intermittently, but it is preferably carried out continuously. For example, when printing with image-forming inks is carried out multiple times, it is preferable to carry out the drying process 1 during the printing of each image-forming ink and / or after the end of printing. In this case, the evaporation amount of the components excluding solids in each image-forming ink may be adjusted to fall within the above range, or the evaporation amount of the components excluding solids in all image-forming inks may be adjusted to fall within the above range.

[0171] 3-2. Step 2 Step 2 is a step of inkjet printing by ejecting a white ink containing a white pigment and a resin onto the surface printed with the image-forming ink.

[0172] The white pigment contained in the white ink, including its preferred embodiments, can be the same as those described in "2-3-1. White Pigment." The content of the white pigment in the solid content of the white ink is preferably 20 to 80% by mass, and more preferably 40 to 60% by mass.

[0173] The resin contained in the white ink is the same as described in "2-3-2. Resin," except that it is preferable that the resin does not have a crosslinked structure due to a crosslinking agent.

[0174] When the resin is added to the white ink, it is preferably added as an emulsion; that is, the resin is preferably contained in the white ink as emulsion particles. The shape of the emulsion particles is not particularly limited, but they are typically spherical. The emulsion particles may be resin particles having a single-phase structure or may be resin particles having a multi-phase structure (preferably a core-shell structure). The average particle diameter of the emulsion particles is, for example, 30 to 500 nm, preferably 80 to 300 nm, more preferably 100 to 300 nm, and even more preferably 150 to 250 nm. Adjusting the average particle diameter of the emulsion particles to the above range makes it easier to incorporate emulsion particles at a high concentration while maintaining the viscosity of the white ink within an appropriate range.

[0175] The resin content in the solid content of the white ink is, for example, 20 to 80% by mass, and preferably 40 to 60% by mass.

[0176] The white ink may further contain one or more crosslinking agents. By including a crosslinking agent in the white ink along with the resin, a crosslinked structure is formed during the drying steps 2 and 3 described below or during transfer printing, allowing for the formation of a tough white print layer while maintaining film-forming properties during printing. The description of the crosslinking agent in "2-3-2. Resin" can be applied mutatis mutandis to the crosslinking agent contained in the white ink, including its preferred embodiments. The content of the crosslinking agent in the white ink is not particularly limited, but is, for example, 0 to 10 parts by mass, preferably 0.1 to 8 parts by mass, and more preferably 0.5 to 5 parts by mass, per 100 parts by mass of the resin in the white ink.

[0177] The white ink may further contain one or more dispersants. The description of "2-3-3. Dispersant" can be applied to the dispersants contained in the white ink, including preferred embodiments thereof. The content of the dispersant is preferably 0.1 to 100 parts by mass, more preferably 1 to 20 parts by mass, per 100 parts by mass of the white pigment.

[0178] The white ink may further contain a surfactant. The explanation of "2-3-4. Surfactant" can be applied mutatis mutandis to the surfactant contained in the white ink, including its preferred embodiments. The content of the surfactant in the solid content of the white ink is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %.

[0179] The white ink preferably further contains one or more solvents. The solvent acts as a diluent to adjust the viscosity of the white ink. As the solvent, organic solvents and aqueous solvents can be suitably used, but from the viewpoint of reducing the environmental load, aqueous solvents are preferably used. Examples of aqueous solvents include water and mixed solvents of water and water-soluble organic solvents.

[0180] The water-soluble organic solvent refers to an organic solvent that dissolves in water at a concentration of 0.01% by mass or more at 25°C and 1 atmosphere. By including a water-soluble organic solvent in the white ink, it is possible to improve the moisture retention and compatibility with resins. The water-soluble organic solvent may be used alone or in combination of two or more. The content of the water-soluble organic solvent is preferably 10 to 55 parts by mass, more preferably 15 to 45 parts by mass, and even more preferably 20 to 35 parts by mass, per 100 parts by mass of water.

[0181] Examples of the water-soluble organic solvent include lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and tert-butyl alcohol (preferably C 1-4alcohol); glycols such as propylene glycol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol; glycerin; monoalkyl ethers of monoalkylene glycols (preferably mono-C), such as monoethylene glycol monomethyl ether, monoethylene glycol monoethyl ether, monoethylene glycol monopropyl ether, monoethylene glycol monoisopropyl ether, monoethylene glycol monobutyl ether, monoethylene glycol monoisobutyl ether, monopropylene glycol monomethyl ether, monopropylene glycol monoethyl ether, monopropylene glycol monopropyl ether, monopropylene glycol monoisopropyl ether, monopropylene glycol monobutyl ether, and monopropylene glycol monoisobutyl ether; 2-3 Alkylene glycol mono C 1-4 alkyl ethers); monoalkyl ethers of dialkylene glycols such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monoisopropyl ether, dipropylene glycol monobutyl ether, and dipropylene glycol monoisobutyl ether (preferably diC 2-3 Alkylene glycol mono C 1-4alkyl ethers); monoalkyl ethers of polyalkylene glycols such as monomethyl ether of polyethylene glycol, monoethyl ether of polyethylene glycol, monopropyl ether of polyethylene glycol, monoisopropyl ether of polyethylene glycol, monobutyl ether of polyethylene glycol, monoisobutyl ether of polyethylene glycol, monomethyl ether of polypropylene glycol, monoethyl ether of polypropylene glycol, monopropyl ether of polypropylene glycol, monoisopropyl ether of polypropylene glycol, monobutyl ether of polypropylene glycol, and monoisobutyl ether of polypropylene glycol (preferably polyC 2-3 Alkylene glycol mono C 1-4 Examples of the alkylene oxide include: alkyl ethers; heterocycles such as 2-pyrrolidone and N-methyl-2-pyrrolidone; and ketones such as acetone and methyl ethyl ketone. The number of moles of alkylene oxide added in the monoalkyl ether of the polyalkylene glycol is preferably 2 to 10, and more preferably 2 to 4.

[0182] In particular, from the viewpoint of further enhancing moisture retention, among the water-soluble organic solvents, solvents having a boiling point of 150°C or higher are preferred, and solvents having a boiling point of 180°C or higher are more preferred. Examples of water-soluble organic solvents having a boiling point of 150°C or higher include propylene glycol, diethylene glycol, triethylene glycol, and glycerin. The content of the water-soluble organic solvent that further enhances moisture retention is preferably 10 to 50 parts by mass, and more preferably 15 to 40 parts by mass, per 100 parts by mass of water. Furthermore, from the viewpoint of further enhancing compatibility with resins, water-soluble organic solvents having a hydrophobic group (e.g., an alkyl group) and a hydroxyl group are preferred, and monoalkyl ethers of dialkylene glycols and / or monoalkyl ethers of polyalkylene glycols (number of moles of alkylene oxide added = 2 to 10, preferably 2 to 4) are more preferred, and di-C 2-3 Alkylene glycol mono C 1-4 Alkyl ether and / or poly C 2-3 Alkylene glycol mono C 1-4Alkyl ethers (number of moles of alkylene oxide added = 2 to 10, preferably 2 to 4) are more preferred, and at least one selected from the group consisting of diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, triethylene glycol monobutyl ether, and tripropylene glycol monomethyl ether is even more preferred. The content of the water-soluble organic solvent that further enhances compatibility is preferably 1 to 15 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of water.

[0183] The content of the solvent in the white ink may be set according to the desired viscosity of the white ink, and is not particularly limited, but is, for example, 40 to 90% by mass, preferably 50 to 88% by mass, and more preferably 55 to 85% by mass.

[0184] The white ink may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. The explanation of "2-3-5. Additives" can be applied mutatis mutandis to the additives contained in the white ink.

[0185] The viscosity of the white ink is preferably 2 to 10 mPa·s, and more preferably 3 to 7 mPa·s, at 25° C. By adjusting the viscosity of the white ink to the above lower limit or more, it is possible to reduce ink drying unevenness, and by adjusting the viscosity to the above upper limit or less, it is possible to impart inkjet ejection stability.

[0186] An example of an apparatus for inkjet printing in step 2 is an inkjet recording apparatus similar to that used in step 1. The number of times the white ink is printed is not particularly limited, and may be, for example, 1 to 6 times, and preferably 1 to 4 times. When printing is performed multiple times, the white ink used in each printing may be the same or different. Furthermore, the amount of ink ejected in one printing is not particularly limited, and may be determined depending on the desired thickness of the white printed layer.

[0187] In step 2, a drying treatment (hereinafter referred to as drying treatment 2) may be performed as needed. Drying treatment 2 is a treatment for evaporating some or all of the components (i.e., solvent) excluding solids in the printed image-forming ink or white ink. In drying treatment 2, preferably 10 to 80% by mass, more preferably 15 to 70% by mass, even more preferably 20 to 60% by mass, and particularly preferably 20 to 50% by mass or 20 to 40% by mass of the components excluding solids in the white ink are evaporated. By adjusting the evaporation amount to the above-mentioned lower limit or above, it is possible to suppress the adhesive ink from flowing in step 3 described below. Furthermore, by adjusting the evaporation amount to the above-mentioned upper limit or below, it is possible to suppress peeling at the interface between the white printing layer and the adhesive layer during transfer printing, thereby further improving transferability. The apparatus and conditions for drying treatment 2, including preferred embodiments, can be similarly described for the apparatus and conditions for drying treatment 1.

[0188] 3-3. Step 3 Step 3 is a step of inkjet printing in which adhesive ink containing an adhesive resin is ejected onto the white ink printing surface.

[0189] The adhesive resin contained in the adhesive ink can be the same as described in "2-4-1. Adhesive Resin," except that it is preferable that the adhesive resin does not have a crosslinked structure due to a crosslinking agent.

[0190] When the adhesive ink contains a resin, it is preferably added as an emulsion; that is, the resin is preferably contained in the adhesive ink as emulsion particles. The shape of the emulsion particles is not particularly limited, but they are typically spherical. The emulsion particles may be resin particles having a single-phase structure or may be resin particles having a multi-phase structure (preferably a core-shell structure). The average particle diameter of the emulsion particles is, for example, 30 to 500 nm, preferably 80 to 300 nm, more preferably 100 to 300 nm, and even more preferably 150 to 250 nm. Adjusting the average particle diameter of the emulsion particles to the above range makes it easier to incorporate emulsion particles at a high concentration while maintaining the viscosity of the adhesive ink within an appropriate range.

[0191] The adhesive resin content in the solid content of the adhesive ink is, for example, 60 to 100% by mass, preferably 80 to 99.5% by mass, and more preferably 90 to 99% by mass.

[0192] The adhesive ink may further contain one or more surfactants. The explanation of "2-4-2. Surfactants" can be applied mutatis mutandis to the surfactant contained in the adhesive ink, including its preferred embodiments. The surfactant content in the solid content of the adhesive ink is, for example, 0.1 to 4 mass %, preferably 0.5 to 3 mass %, and more preferably 1 to 2.5 mass %.

[0193] The adhesive ink preferably further contains one or more solvents. The solvent acts as a diluent to adjust the viscosity of the adhesive ink. The same explanation as for the solvent contained in the white ink, including preferred embodiments thereof, can be applied to the solvent contained in the adhesive ink. The content of the solvent in the adhesive ink may be set according to the desired viscosity of the adhesive ink and is not particularly limited, but is, for example, 40 to 90% by mass, preferably 50 to 88% by mass, and more preferably 60 to 85% by mass.

[0194] The adhesive ink may contain one or more additives other than the above-described components, as long as the object of the present disclosure is not impaired. The explanation of "2-4-3. Additives" can be applied mutatis mutandis to the additives contained in the adhesive ink.

[0195] The pH of the adhesive ink at 25° C. is preferably 7 to 10, and more preferably 7 to 9. By adjusting the pH of the adhesive ink to fall within the above range, the dispersion stability of the ink can be improved.

[0196] The adhesive ink preferably has a static surface tension at 25°C of 22 to 35 mN / m, more preferably 24 to 30 mN / m, and even more preferably 25 to 26.5 mN / m. By adjusting the static surface tension of the adhesive ink to be equal to or greater than the lower limit, the amount of leveling agent can be reduced, and by adjusting the static surface tension to be equal to or less than the upper limit, uneven drying of the ink can be reduced. The static surface tension of the ink can be measured using a surface tensiometer or the like according to the Wilhelmy method.

[0197] The adhesive ink preferably has a viscosity of 2 to 10 mPa·s, and more preferably 3 to 7 mPa·s, at 25° C. Adjusting the viscosity of the adhesive ink to the above lower limit or more can reduce ink drying unevenness, while adjusting the viscosity to the above upper limit or less can impart inkjet ejection stability.

[0198] An example of an apparatus for inkjet printing in step 3 is an inkjet recording apparatus similar to that used in step 1. The number of times the adhesive ink is printed is not particularly limited and may be determined depending on the desired thickness of the adhesive layer, and is, for example, 1 to 6 times, and preferably 1 to 4 times. Furthermore, in step 3, the amount of ink ejected in one printing is not particularly limited and may be determined depending on the desired thickness of the adhesive layer.

[0199] In step 3, a drying treatment (hereinafter referred to as drying treatment 3) may be performed as needed. Drying treatment 3 is a step of evaporating some or all of the components (i.e., solvent) excluding the solid content of the image-forming ink, white ink, and adhesive ink.

[0200] In the above process, preferably 80 to 100% by mass, more preferably 90 to 100% by mass, of 100% by mass of the adhesive ink components excluding solids, is evaporated. The drying apparatus and conditions described in step 1, including preferred embodiments, can be applied mutatis mutandis. Furthermore, in drying process 3, drying can be performed using means such as natural drying, heating, reduced pressure, and contact with dry air or hot air, as needed. Hereinafter, this drying process may be referred to as drying process 3a. In drying process 3a, the heating temperature, heating time, pressure, hot air temperature, and air volume can be appropriately set depending on the desired evaporation amount. For example, when drying is performed by heating or contact with hot air, the heating temperature and hot air temperature are preferably 40 to 180°C, more preferably 80 to 160°C, and even more preferably 100 to 160°C. The heating time and hot air contact time are preferably 0.5 to 30 minutes, more preferably 1 to 20 minutes. In the drying treatment 3, it is preferable that drying by a heating means in the inkjet recording apparatus (preferably drying by a platen heater or a planar heating element) is performed continuously while the adhesive ink is being printed, and that further drying treatment 3a (preferably drying by heat or contact with hot air) is performed after the printing of the adhesive ink. Furthermore, when printing of adhesive inks is performed multiple times, it is preferable that the adhesive ink is dried by a heating means or an alternative means in the inkjet recording apparatus during and / or after the printing of each adhesive ink, and then dried by heat or contact with hot air after all printing is completed. In this case, the evaporation amount of the components excluding solids in each adhesive ink may be adjusted to be within the above range, or the evaporation amount of the components excluding solids in all adhesive inks may be adjusted to be within the above range.

[0201] The transfer sheet of the present disclosure can be produced by carrying out the above steps 1, 2, and 3 in this order, setting the film thickness A of the white printing layer formed from the white ink to 5 to 35 μm, the film thickness B of the adhesive layer formed from the adhesive ink to 5 to 50 μm, and the thickness C of the transfer sheet to 25 to 200 μm.

[0202] 4. Transfer Printing The transfer sheet of the present disclosure can be used for transfer printing. That is, a transfer-printed item can be produced by using the transfer sheet of the present disclosure to transfer the image-forming layer, the white printing layer, and the adhesive layer to a transfer-receiving medium. Specifically, the surface of the transfer sheet of the present disclosure on which the adhesive layer is formed is brought into close contact with the transfer-receiving medium while facing it, and then the base layer is peeled off, thereby transferring the desired image to the transfer-receiving medium, i.e., a transfer-printed item can be produced.

[0203] The transfer medium is not particularly limited, and can be metal, wood, resin (plastic), paper, fabric, etc. The metal, wood, resin (plastic), and paper that can be used as the transfer medium are the same as the examples of the metal, wood, resin (plastic), and paper that can be used as the transfer substrate described above.

[0204] From the viewpoint of maximizing the effects of using the adhesive ink of the present disclosure, it is preferable to use fabric as the transfer medium. The fabric is not particularly limited and includes all textile products such as cloth and textiles made from natural and / or synthetic fibers. Examples of fabric include woven fabric, nonwoven fabric, and knitted fabric. The fibers constituting the fabric are also not particularly limited and include, for example, natural fibers, chemical fibers, or mixtures thereof.

[0205] Preferred examples of natural fibers include silk, cotton, and wool. Preferred examples of chemical fibers include synthetic fibers, regenerated fibers, and semi-synthetic fibers. Preferred examples of synthetic fibers include polyester fibers, nylon fibers, acrylic fibers, polyurethane fibers, polyethylene fibers, polypropylene fibers, and vinylon fibers. Preferred examples of regenerated fibers include rayon. Preferred examples of semi-synthetic fibers include acetate and triacetate. Among these, fabrics made from cotton, polyester fibers, polypropylene fibers, nylon fibers, or mixtures thereof are preferred, and fabrics made from cotton, polyester fibers, nylon fibers, or mixtures thereof are more preferred.

[0206] The printed matter of the present disclosure has excellent wash and tumble dry fastness, and therefore can also be used as the fabric in textile products such as clothing, handkerchiefs, scarves, towels, towel blankets, blankets, cloth bags, tablecloths, curtains, sheets, bed covers, quilt covers, pillowcases, and sofa covers.

[0207] The step of bringing the transfer sheet and the transfer receiving medium into close contact with each other (hereinafter referred to as the "close contact step") preferably includes heating and pressurization as necessary. Examples of the close contact step include a method in which the transfer sheet is brought into close contact with the transfer receiving medium using a press or a heated drum, and then heat and pressurization are applied.

[0208] The heating temperature in the adhesion step is not particularly limited, but is preferably 80 to 200° C., and more preferably 100 to 180° C. The pressure in the adhesion step is also not particularly limited, but is preferably 100 to 600 g / cm. 2 is preferable, and more preferably 200 to 500 g / cm 2 is.

[0209] The contact time is preferably 1 second or more, more preferably 3 seconds or more, from the viewpoint of further improving transferability. The upper limit of the contact time is not particularly limited, but from the viewpoint of productivity, it is preferably 1 minute or less, more preferably 30 seconds or less. That is, the contact time is preferably 1 second to 1 minute, more preferably 3 seconds to 30 seconds.

[0210] After the adhesion step, the substrate layer is peeled off from the transfer medium to obtain the desired transfer print. Note that, from the viewpoint of further reducing the amount of image remaining on the substrate layer (specifically, further suppressing the image-forming layer, white printing layer, and adhesive layer from remaining on the substrate layer), it is preferable to peel off the substrate layer after the temperature of the transfer medium has reached 60°C or less (particularly 40°C or less).

[0211] The resulting transfer print may be further heated and pressurized using a press or a heated drum. By subjecting the resulting transfer print to additional heating and pressure treatment, the image and the transfer medium are more tightly pressed together, further improving durability (preferably washing and tumble drying fastness). The heating temperature in this step is not particularly limited, but is preferably 80 to 200°C, and more preferably 100 to 180°C. The pressure in this step is also not particularly limited, but is preferably 100 to 600 g / cm. 2 is preferable, and more preferably 200 to 500 g / cm 2 The heating and pressurizing time in this step is not particularly limited, but is preferably from 1 second to 1 minute, and more preferably from 3 seconds to 30 seconds.

[0212] 5. Transfer Printed Material A transfer printed material obtained using the transfer sheet of the present disclosure has an adhesive layer, a white printing layer, and an image-forming layer laminated in this order on a receiving medium. The materials and compositions of the receiving medium, adhesive layer, white printing layer, and image-forming layer in the transfer printed material, including preferred embodiments thereof, can be applied mutatis mutandis to the above-mentioned explanations. However, since the thickness of each layer in the transfer printed material may change depending on processing conditions such as heating and pressure during transfer printing, the thickness of each layer in the transfer printed material does not have to be the same as the thickness of each layer in the transfer sheet. Because the transfer printed material is produced using the transfer sheet of the present disclosure, it has excellent texture and durability (preferably washing and tumble drying fastness).

[0213] This application claims the benefit of priority based on Japanese Patent Application No. 2024-109159, filed on July 5, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-109159, filed on July 5, 2024, are incorporated herein by reference.

[0214] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples. Unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

[0215] [Resin Production] (Resin Production Example 1) 350 parts of deionized water was charged into a polymerization vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube, and dropping funnels A and B. Thereafter, the internal temperature was raised to 75°C while stirring under a nitrogen gas stream. Meanwhile, a monomer emulsion A consisting of 265 parts of methyl methacrylate, 225 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid as monomer components, 3.0 parts of t-dodecyl mercaptan as a polymerization chain transfer agent, 31.25 parts of Softanol 300 (manufactured by Nippon Shokubai) and 31.25 parts of Latemul WX (trade name, manufactured by Kao Corporation), each of which had been previously prepared as a 20% aqueous solution, and 91.5 parts of deionized water was charged into the dropping funnel A. Furthermore, the dropping funnel B was charged with a monomer emulsion B having the same composition as the monomer emulsion A, except that 2.0 parts of t-dodecyl mercaptan was used instead of the monomer emulsion A. Next, while maintaining the internal temperature of the polymerization vessel at 75°C, 27.0 parts of the monomer emulsion A and 5 parts of a 5% aqueous potassium persulfate solution (oxidizing agent) and 10 parts of a 2% aqueous sodium hydrogen sulfite solution (reducing agent), which served as polymerization initiators (oxidizing agents), were added to initiate prepolymerization. After 40 minutes, while maintaining the reaction system at 80°C, the remaining monomer emulsion A was added dropwise uniformly over 105 minutes. Simultaneously with the monomer emulsion A, 45 parts of a 5% aqueous potassium persulfate solution and 40 parts of a 2% aqueous sodium hydrogen sulfite solution were added dropwise uniformly over 105 minutes. Immediately after the dropwise addition of the monomer emulsion A was completed, the monomer emulsion B was added dropwise uniformly over 105 minutes. Simultaneously with the monomer emulsion B, 50 parts of a 5% aqueous potassium persulfate solution and 50 parts of a 2% aqueous sodium hydrogen sulfite solution were uniformly added dropwise over 105 minutes. After the completion of the dropwise addition of the monomer emulsion B, the temperature was maintained for 60 minutes, and the polymerization was terminated. The resulting reaction solution was cooled to room temperature, and then 16.7 parts of 2-(dimethylamino)ethanolamine as a pH adjuster (neutralizer) and 39 parts of deionized water were added to obtain an emulsion containing an acrylic resin as emulsion particles (hereinafter referred to as emulsion 1). The solids content of emulsion 1 was 54%. The emulsion particles contained in emulsion 1 had an average particle size of 200 nm, a Tg of 0°C, a weight-average molecular weight Mw of 180,000, and a molecular weight distribution of 5.

[0216] Resin Production Example 2 350 parts of deionized water were charged into a polymerization vessel equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube, and a dropping funnel. Thereafter, the internal temperature was raised to 75°C while stirring under a nitrogen gas stream. Meanwhile, the dropping funnel was charged with a monomer emulsion C consisting of 20 parts of acrylic acid, 570 parts of 2-ethylhexyl acrylate, 50 parts of cyclohexyl methacrylate, 10 parts of hydroxyethyl methacrylate, 350 parts of styrene as monomer components, 0.5 parts of t-dodecyl mercaptan as a polymerization chain transfer agent, 62.5 parts of Softanol 300 (manufactured by Nippon Shokubai) and 62.5 parts of Latemul WX (trade name, manufactured by Kao Corporation), each of which had been previously prepared as a 20% aqueous solution, and 183 parts of deionized water. Next, while maintaining the internal temperature of the polymerization vessel at 75°C, 27.0 parts of the monomer emulsion C and 5 parts of a 5% aqueous potassium persulfate solution and 10 parts of a 2% aqueous sodium hydrogen sulfite solution as polymerization initiators (oxidizers) were added to initiate prepolymerization. After 40 minutes, the remaining monomer emulsion C was added dropwise over 210 minutes while maintaining the reaction system at 80°C. Simultaneously with the monomer emulsion C, 95 parts of a 5% aqueous potassium persulfate solution and 90 parts of a 2% aqueous sodium hydrogen sulfite solution were added dropwise over 210 minutes. After the dropwise addition of the monomer emulsion C was completed, the same temperature was maintained for 60 minutes, and polymerization was terminated. The resulting reaction solution was cooled to room temperature, and then 29.8 parts of 2-dimethylethanolamine and 39 parts of deionized water were added as a pH adjuster (neutralizer) to obtain an emulsion containing an acrylic resin as emulsion particles (hereinafter referred to as emulsion 2). The solids content of emulsion 2 was 54%. The emulsion particles contained in emulsion 2 had an average particle size of 200 nm, a Tg of −20° C., and a weight average molecular weight Mw of 700,000.

[0217] [Measurement of Average Particle Diameter of Emulsion Particles] The average particle diameter of emulsion particles was measured using the emulsion obtained in each Production Example as a measurement sample with a particle size distribution analyzer (manufactured by Otsuka Electronics Co., Ltd., product number: FPAR-1000) by dynamic light scattering, and was determined using cumulant analysis.

[0218] [Measurement of Resin Tg] The glass transition temperature (Tg) of the emulsion particles (resin) was measured by differential scanning calorimetry (DSC) under the following measurement conditions. Measurement equipment: DSC 3500 (trade name, manufactured by NETZSCH) Sample container: sealed aluminum container Sample weight: 10 mg ± 2 mg Measurement method: In a N atmosphere, two cycles were performed, each cycle consisting of heating from -50°C to 150°C and cooling from 150°C to -50°C. The heating and cooling rates were both 10°C / min, and the holding times at -50°C and 150°C were 5 minutes. Using the analysis software Proteus Analysis, the glass transition temperature was analyzed from the DSC curve chart during the second heating cycle, and the midpoint glass transition temperature was used.

[0219] [Measurement of Weight-Average Molecular Weight and Molecular Weight Distribution of Resin] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of emulsion particles (resin) were measured by GPC (gel permeation chromatography) under the following measurement conditions. Measuring instrument: HLC-8320GPC (trade name, manufactured by Tosoh Corporation) Molecular weight column: TSK-GEL SuperMultiporeHZ (manufactured by Tosoh Corporation) Eluent: tetrahydrofuran (THF) Calibration curve standard: polystyrene (manufactured by Tosoh Corporation) Measurement method: The measurement object was dissolved in THF to a solid content of approximately 0.2 mass%, and the resultant solution was filtered through a filter to measure the molecular weight. The flow rate of the liquid delivery pump was 0.35 ml / min. The ratio of the weight-average molecular weight to the number-average molecular weight (Mw / Mn) obtained above was taken as the molecular weight distribution.

[0220] [Preparation of Pigment Dispersion] (Pigment Dispersion Production Example 1) 5 parts of a dispersant, Discoat N-14 (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), 6 parts of propylene glycol, 70 parts of deionized water, 100 parts of titanium oxide, CR-95 (manufactured by Ishihara Sangyo Kaisha, Ltd.), and zirconia beads with a particle size of 0.5 mm were filled to a volume ratio of 50%, dispersed using a bead mill, and filtered through a 1 μm pore filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.) to obtain a white pigment dispersion containing 55% pigment (hereinafter referred to as Pigment Dispersion 1). The average particle size of the pigment was 330 nm.

[0221] (Pigment Dispersion Production Example 2) 3 parts of a dispersant, Joncryl 678 (manufactured by BASF), 1.3 parts of dimethylaminoethanol, and 81 parts of deionized water were mixed and stirred at 70°C. Next, 15 parts of a blue pigment, C.I. Pigment Blue 15:3 LIONOL BLUE FG-7330 (manufactured by Toyo Ink Co., Ltd.), 0.1 parts of a surfactant, Olfine D-10PG (manufactured by Nissin Chemical Industry Co., Ltd.), and zirconia beads with a particle size of 0.5 mm were added to a volumetric pack of 50%. The mixture was dispersed using a bead mill and filtered through a 1 μm pore size filter (MCP-1-C10S, manufactured by Advantec Co., Ltd.) to obtain a blue pigment dispersion containing 15% pigment (hereinafter referred to as Pigment Dispersion 2). The average particle size of the pigment was 90 nm.

[0222] [Measurement of Average Particle Diameter of Pigment] The average particle diameter of the pigment described above was determined by measuring the pigment dispersion obtained in each Production Example as a measurement sample using a particle size distribution measuring instrument (manufactured by Otsuka Electronics Co., Ltd., product number: FPAR-1000) based on a dynamic light scattering method, and then by cumulant analysis.

[0223] [Preparation of White Ink] A white ink was produced by mixing 27.8 parts of Emulsion 2 (15 parts as emulsion particles), 23 parts of Pigment Dispersion 1, 1.2 parts (0.3 parts as solids) of Epocross WS-700 (manufactured by Nippon Shokubai, solids content 25%), 2 parts of diethylene glycol monobutyl ether, 15 parts of triethylene glycol, 0.3 parts of surfactant KF-6011 (manufactured by Shin-Etsu Chemical, polyether-modified silicone surfactant), and 28.5 parts of deionized water and filtering the mixture through a 1 μm pore size filter (manufactured by Advantec, MCP-1-C10S).

[0224] [Preparation of Cyan Ink] A cyan ink was produced in the same manner as in the preparation of the white ink, except that Pigment Dispersion 1 was changed to Pigment Dispersion 2.

[0225] [Preparation of Adhesive Ink] 25 parts of emulsion 1 as emulsion particles, 2 parts of diethylene glycol monobutyl ether, 15 parts of triethylene glycol, 0.6 parts of a surfactant KF-6011 (manufactured by Shin-Etsu Chemical Co., Ltd.), and deionized water were added to make a total of 100 parts, mixed, and filtered through a 1 μm pore size filter (manufactured by Advantec, MCP-1-C10S), to produce an adhesive ink.

[0226] [Preparation of transfer substrate] (Transfer substrate A) An ink-receiving layer forming agent containing silica particles and a wax resin was applied to one side of a polyester resin film (thickness 75 μm) to obtain a transfer substrate A (film thickness 80 μm) coated with an ink-receiving layer having a thickness of 5 μm.

[0227] (Transfer substrate B) An ink-receiving layer forming agent containing silica particles and a wax resin was applied to one side of a polyester resin film (thickness 100 μm) to obtain a transfer substrate B (film thickness 105 μm) coated with an ink-receiving layer having a thickness of 5 μm.

[0228] (Transfer substrate C) An ink-receiving layer forming agent containing silica particles and a wax resin was applied to one side of a polyester resin film (thickness 38 μm) to obtain a transfer substrate C (film thickness 43 μm) coated with an ink-receiving layer having a thickness of 5 μm.

[0229] (Transfer substrate D) An ink-receiving layer forming agent containing silica particles and a wax resin was applied to one side of a polyester resin film (thickness 150 μm) to obtain a transfer substrate D (film thickness 155 μm) coated with an ink-receiving layer having a thickness of 5 μm.

[0230] The thickness of the polyester resin film and the thickness of the ink-receiving layer were measured by cutting the transfer substrate and observing its cross section using a field emission electron microscope (JSM-7600F, manufactured by JEOL Ltd.). It is recommended that the measurement sample for the cross-sectional observation be a film cross section obtained by cutting a 10 mm x 10 mm central portion of the transfer substrate perpendicular to the substrate surface, followed by Pt deposition. It is also recommended that the cross-sectional observation be performed by capturing an image so that the layer direction in the cross section of the transfer substrate is parallel to the horizontal direction of the image and so that the entire cross section of the transfer substrate in the thickness direction is included, i.e., so that all layers constituting the transfer substrate are included. When measuring each thickness (thickness of the resin film and thickness of the ink-receiving layer) from the obtained image, it is recommended that 18 line segments be drawn vertically on the image so as to divide the horizontal direction of the image into 19 equal parts, and that the thicknesses be measured at 20 line segments, including both horizontal ends of the image, and that the average value of the 20 measured values ​​obtained for each thickness be used. The thickness was measured at any five points by the cross-sectional observation, and the average value of the five points was used as the thickness. The sum of the thickness of the resin film and the thickness of the ink-receiving layer obtained above was used as the thickness of the transfer substrate.

[0231] [Examples 1 to 7, Comparative Examples 1 to 5] [Production of Transfer Sheet] (Preparation of Inkjet Ejection Device) Two printers (MMP-TX13) manufactured by Mastermind were prepared, designated Printer A and Printer B. In each printer, a rubber heater was installed on the platen and heated to 50°C. Printer A was filled with white ink and cyan ink, which is an image forming ink. Printer B was filled with adhesive ink.

[0232] Using the ink and transfer substrate prepared above, two transfer sheets were prepared using the following printing and drying processes. One of the sheets was used to measure the film thickness. The other sheet was subjected to the transfer process described below, and then various properties of the transfer print were evaluated. The results are shown in Table 1.

[0233] (Printing step) A transfer substrate shown in Table 1 was placed on a rubber heater, and an image was formed by the inkjet method. Specifically, solid printing (8 × 16 cm) was performed with cyan ink using printer A. 2 ) and then printed solidly with white ink (8 x 16 cm 2 The printed transfer substrate was transferred to printer B, and a solid print (8 × 16 cm) was further printed on it with adhesive ink. 2 The amount of cyan ink ejected per unit area was 10 g / m 2 The ejection amounts of the white ink and adhesive ink were adjusted so that the desired film thicknesses of the white printing layer and adhesive layer were obtained. Note that image formation was carried out on the ink-receiving layer side.

[0234] (Drying Step) The substrate on which the image was formed was dried in a hot air dryer at 150° C. for 15 minutes to prepare a transfer sheet.

[0235] (Film Thickness Measurement) After Pt vapor deposition on the film cross section obtained by cutting a 10 mm x 10 mm central portion of the transfer sheet perpendicular to the sheet surface, 500x magnified photographs were taken of five randomly selected locations using a field emission electron microscope (JEOL Ltd., JSM-7600F). It is recommended that the images be taken so that the layer direction in the sheet cross section is horizontal to the horizontal direction of the image. It is also recommended that each of the five images be taken so that the entire cross section of the transfer sheet in the thickness direction is included, i.e., each image obtained includes all layers constituting the sample, such as the white printed layer, adhesive layer, and transfer substrate. The thickness of the transfer sheet was measured for each captured image. Furthermore, EDS mapping of Ti element was performed on the captured images, and the film thickness of the white printed layer was measured by defining the region where Ti element was detected as the white printed layer. The film thickness of the adhesive layer was also measured by defining the length from the interface between the white printed layer and adhesive layer to the upper interface of the adhesive layer as the adhesive layer. Regarding the thickness of each image (thickness of the white printing layer, thickness of the adhesive layer, and thickness of the transfer sheet), it is recommended to draw 18 lines vertically on the image so as to divide the horizontal direction of each image into 19 equal parts, measure each thickness at 20 lines including both horizontal ends of the image, and use the average value of the 20 measurements obtained for each thickness as the thickness of each image. For five images, the thickness of the white printing layer, thickness of the adhesive layer, and thickness of the transfer sheet were measured using the above method, and the average values ​​of the five points were taken as the thickness A of the white printing layer, the thickness B of the adhesive layer, and the thickness C of the transfer sheet, respectively. The results are shown in Table 1.

[0236] [Production of Transfer Printed Material] (Transfer Process) A transfer press machine TP-630M manufactured by Horizon International was used. The heating temperature was 150°C, and the press load was 3 kN (transfer pressure: 400 g / cm 2) was set. The fabric, which was the transfer medium, was placed on the lower iron, and then the transfer sheet was placed on top of that with the printed side facing down, and stamped for 10 seconds. After stamping, when the temperature of the fabric had dropped to 40°C or less, the transfer substrate was peeled off from the fabric, and a transfer print was obtained. The resulting transfer print was then placed again on the lower iron, silicone release paper was placed on top of the transfer print, and stamped for 5 seconds, thereby pressing the image onto the fabric. In the above transfer process, a 100% cotton white T-shirt manufactured by Hanes was used as the cotton fabric.

[0237] [Characteristics Evaluation] (1) Transferability Evaluation After the transfer process, the transfer substrate obtained in each Example and Comparative Example was visually inspected to see whether or not the image printed by the inkjet printer remained on it. If the image remained, it was marked with "x", and if it did not remain, it was marked with "o", and the transferability evaluation was deemed to be "pass".

[0238] (2) Texture evaluation The texture of the transfer prints obtained in each example and comparative example was evaluated by touch. If the transfer print bends easily and feels similar to the softness of fabric itself, it is evaluated as ◯, and if the transfer print feels stiff, it is evaluated as ×. A ◯ indicates that the texture evaluation is acceptable.

[0239] (3) Evaluation of Washing and Tumble Drying Fastness of Transfer Printed Materials The transfer printed materials obtained in each Example and Comparative Example were washed and tumble dried under the following conditions, and the material obtained after tumble drying was used as a sample. (Washing conditions) Washing machine: Model No. NA-F5B1 (Panasonic) Water volume: 32 L Course: 1 rinse (Wash → Rinse (1) → Spin) Detergent: Ariel Liquid Disinfectant Plus Laundry Detergent (P&G), Amount used: 35 g (Tumble drying conditions) Tumble dryer: Model No. NH-D503 (Panasonic) Course: Standard The samples obtained by the above method were evaluated for washing and tumble drying fastness on a 5-point scale (ratings 1 to 5) based on the number of cracks in the print visually confirmed. The fewer the number of cracks, the better the washing and tumble drying fastness, and a rating of 3 or higher was considered a pass for washing and tumble drying fastness. In Comparative Examples 3 and 5, it was not possible to transfer all of the images, and therefore it was not possible to evaluate the washing and tumble drying fastness of the transfer print. 5: 0 cracks 4: 1 to 3 cracks 3: 4 to 10 cracks 2: 11 to 20 cracks 1: 21 or more cracks

[0240]

[0241] In Examples 1 to 7, in which the thickness A of the white printing layer, the thickness B of the adhesive layer, and the thickness C of the transfer sheet were adjusted within the specified ranges, the transferability was excellent, and the resulting transfer prints exhibited excellent texture and washing and tumble drying fastness.

[0242] 100 Transfer sheet 1 Transfer substrate 1a Inkjet ink receiving layer 2 Image forming layer 3 White print layer 4 Adhesive layer

Claims

1. A transfer sheet in which an image forming layer, a white printed layer containing a white pigment and a resin, and an adhesive layer containing an adhesive resin are laminated in this order on the ink receiving layer forming surface of a transfer substrate having an ink jet ink receiving layer, wherein the thickness A of the white printed layer is 5 to 35 μm, the thickness B of the adhesive layer is 5 to 50 μm, and the thickness C of the transfer sheet is 25 to 200 μm.

2. The transfer sheet according to claim 1, wherein the ratio (A / B) of the thickness A of the white print layer to the thickness B of the adhesive layer is 0.2 to 4.

0.

3. The transfer sheet according to claim 1, wherein the transfer substrate is paper or a resin film having an ink-jet ink-receiving layer.

4. The transfer sheet according to claim 1, wherein the adhesive resin contained in the adhesive layer is at least one selected from the group consisting of acrylic resins, polyester resins, and polyurethane resins.

5. The transfer sheet according to claim 1, wherein the adhesive resin contained in the adhesive layer has a glass transition temperature higher than the glass transition temperature of the resin contained in the white print layer.

6. The transfer sheet according to claim 1, wherein the adhesive resin contained in the adhesive layer has a weight average molecular weight of 5,000 to 700,000.

7. The transfer sheet according to claim 1, wherein the adhesive resin contained in the adhesive layer has a molecular weight distribution of 4 to 12.

8. The transfer sheet according to claim 1, wherein the image forming layer comprises a colorant and a resin.

9. The transfer sheet according to claim 1, which is used for transferring onto fabric.

10. A method for manufacturing a transfer sheet, comprising the steps of: inkjet printing by ejecting an image-forming ink onto the ink-receiving layer-forming surface of a transfer substrate having an inkjet ink-receiving layer; inkjet printing by ejecting a white ink containing a white pigment and a resin onto the surface printed with the image-forming ink; and inkjet printing by ejecting an adhesive ink containing an adhesive resin onto the surface printed with the white ink, in this order; wherein the thickness A of the white printing layer formed from the white ink is 5 to 35 μm, the thickness B of the adhesive layer formed from the adhesive ink is 5 to 50 μm, and the thickness C of the transfer sheet is 25 to 200 μm.

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