Transcription paper

Abstract

To provide a transfer sheet used in a transfer printing method that uses printing ink, wherein the transfer sheet can suitably adhere to a printing object, offers favorable transfer efficiency, has heat resistance, and has a barrier function at transfer.SOLUTION: The present invention discloses a transfer sheet used in a transfer printing method, the transfer sheet comprising a base sheet and one or more coating layers on at least one surface of the base sheet, wherein an outermost coating layer, located farthest out relative to the base sheet, contains calcined kaolin, carboxymethyl cellulose and polyvinyl alcohol.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to transfer paper used for transferring a pattern in a transfer printing method using printing ink for forming a pattern on a printed material such as a fiber material. In particular, it relates to transfer paper suitable for a transfer printing method using sublimation type printing ink.

Background Art

[0002] When printing on sublimation type transfer paper using sublimation printing ink, it has excellent drying property, image reproducibility, back bleeding prevention property and heat resistance of the sublimation printing ink, and also has good characteristics in terms of image reproducibility and transfer efficiency of the material to be transferred by transfer. As a sublimation type transfer paper, it has a sublimation printing ink receiving layer on a base material. The sublimation printing ink receiving layer contains a water-soluble resin and fine particles. The fine particles are synthetic amorphous silica. As the water-soluble resin, polyvinyl alcohol is contained in a ratio of 1 to 200 parts by weight with respect to 100 parts by weight of the fine particles, and carboxymethyl cellulose is contained in a ratio of 20 to 399 parts by weight with respect to 100 parts by weight of the fine particles. The water absorption of the sublimation type printing ink receiving layer conforming to JIS P 8140 is 15 g / m 2 or more, and a sublimation type transfer paper is known in which irregularities are formed on the surface of the sublimation printing ink receiving layer (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Transfer papers such as Patent Document 1, whose coating layer that adheres to the object to be printed during transfer contains amorphous silica, carboxymethyl cellulose, and polyvinyl alcohol, are excellent in ink drying property, image quality of the pattern, and prevention of ink bleeding on the transfer paper after the pattern is printed. This is due to amorphous silica, which is a porous white inorganic pigment. On the other hand, transfer papers whose coating layer contains amorphous silica may have deteriorated properties of being able to adhere well to the object to be printed or deteriorated transfer efficiency. Here, transfer efficiency relates to the ease of transfer from the transfer paper to the object to be printed. Good transfer efficiency means that if the amount of energy during transfer is constant, the transfer progresses in a short time, or if the time during transfer is constant, the transfer progresses with a small amount of energy. When the property of being able to adhere deteriorates, misregistration or the like occurs during the transfer process, and the image quality of the pattern formed on the object to be printed deteriorates. When the transfer efficiency deteriorates, relatively large energy is required to transfer the coloring material in the printing ink during the transfer process. For example, when transferring under the same temperature conditions, it takes a relatively long time.

[0005] Also, for example, transfer papers whose coating layer that adheres to the object to be printed during transfer is a resin layer composed of carboxymethyl cellulose and polyvinyl alcohol may have the coating layer thermally shrink during the transfer process. When the transfer paper and the object to be printed are in a state of being in close contact and the coating layer of the transfer paper thermally shrinks with respect to the object to be printed, another extremely thin contour line is generated along the contour of the original pattern formed on the object to be printed. Therefore, the transfer paper is required to have a quality that suppresses thermal shrinkage.

[0006] Also, during transfer, the transfer paper and the object to be printed are brought into close contact with each other. Transfer is performed by heating or heating and pressing with respect to the state where the transfer paper and the object to be printed are in close contact. During transfer, the coloring material in the printing ink is transferred from the transfer paper to the object to be printed. However, the coloring material may also go to the opposite side of the transfer paper (the side not in close contact with the object to be printed) in addition to going toward the object to be printed. The coloring material that has gone to the opposite side becomes a loss. The loss of the coloring material also has an adverse effect on the transfer efficiency and the color development of the pattern formed on the object to be printed. Usually, although the cost increases, in consideration of the loss of the coloring material, the concentration of the printing ink is increased to form a pattern on the transfer paper. Therefore, the transfer paper is required to have a barrier property that suppresses the coloring material from going to the opposite side during transfer and reduces the loss of the coloring material.

[0007] In view of the above, an object of the present invention is to provide a transfer paper having the following items. (1) Having a property of being able to adhere well to the object to be printed on the transfer paper. (2) Having good transfer efficiency in the transfer paper. (3) Having heat resistance that suppresses heat shrinkage of the coating layer of the transfer paper during transfer. (4) Having a transfer barrier property that can reduce the loss of the coloring material.

Means for Solving the Problems

[0008] The inventors of the present invention have conducted intensive research to solve the above problems. As a result, the object of the present invention is achieved as follows.

[0009] [1] A transfer paper for use in the transfer printing method, having a base paper and one or two or more coating layers on at least one side of the base paper, wherein the outermost coating layer located outermost with respect to the base paper contains calcined kaolin, carboxymethyl cellulose, and polyvinyl alcohol.

[0010] [2] The transfer paper according to [1] above, wherein in the outermost coating layer, the content mass ratio of the carboxymethyl cellulose and the polyvinyl alcohol is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the carboxymethyl cellulose.

[0011] [3] The transfer paper according to [1] or [2] above, wherein the polyvinyl alcohol is a carboxyl group-modified polyvinyl alcohol.

Effect of the Invention

[0012] According to the present invention, it is possible to provide transfer paper for use in the transfer printing method, which has the property of being able to adhere well to the object to be printed, has good transfer efficiency, has heat resistance, and has barrier properties during transfer.

Mode for Carrying Out the Invention

[0013] The present invention will be described in detail below. In the present invention, the "transfer paper" refers to a paper in a white paper state before the pattern to be transferred is printed. The "transfer sheet" refers to a paper in a state where the pattern to be transferred is printed on the transfer paper.

[0014] The transfer paper has a base paper and one or two or more coating layers on at least one side of the base paper layer. The base paper is made of a sheet paper obtained by papermaking a paper stock in which one or more kinds of pulp selected from chemical pulps such as LBKP (Leaf Bleached Kraft Pulp) and NBKP (Needle Bleached Kraft Pulp), mechanical pulps such as GP (Groundwood Pulp), PGW (Pressure GroundWood pulp), RMP (Refiner Mechanical Pulp), TMP (ThermoMechanical Pulp), CTMP (ChemiThermoMechanical Pulp), CMP (ChemiMechanical Pulp), CGP (ChemiGroundwood Pulp), and waste paper pulp such as DIP (DeInked Pulp) are dispersed, and fillers such as calcium carbonate, talc, clay, and various kaolins are further added. In addition, various additives such as binders, sizing agents, fixing agents, retention agents, cationizing agents, paper strength agents, pigment dispersants, thickeners, fluidity improvers, defoaming agents, foam suppressants, release agents, foaming agents, penetrants, coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, anti-mildew agents, and water resistance agents are blended as required. Further, the base paper includes high-quality paper obtained by subjecting the sheet paper to calendering treatment, surface sizing treatment or surface treatment with starch, styrene-acrylic resin, etc. Further, the base paper includes high-quality paper obtained by calendering treatment after surface sizing treatment or surface treatment.

[0015] In some embodiments, the density of the above sheet paper, as determined in accordance with ISO534:2011 "Paper and board - Determination of thickness, density and specific volume", is 0.75 g / cm 3 or more and 0.85 g / cm 3 or less. The reason for this is that the property of being able to adhere well to the object to be printed is improved.

[0016] The papermaking is carried out using a conventionally known paper machine after adjusting the furnish to be acidic, neutral or alkaline. Examples of paper machines include a Fourdrinier paper machine, a twin-wire paper machine, a combination paper machine, a cylinder paper machine, a Yankee paper machine, etc. The calendering is carried out using a conventionally known calendering device. Examples of calendering devices include a machine calender, a soft nip calender, a super calender, a multi-stage calender, a multi-nip calender, etc.

[0017] In some embodiments, the pulp has a total of 80% by mass or more of LBKP and NBKP with respect to the pulp of the base paper, and 75% by mass or more and 95% by mass or less of LBKP in the range of 380 ml or more and 480 ml or less of drainage degree, and 5% by mass or more and 25% by mass or less of NBKP in the range of 400 ml or more and 480 ml or less of drainage degree. The reasons for this are that the characteristics of being able to adhere well to the object to be printed and the transfer efficiency are improved. The property of being able to adhere well to the object to be printed is related to the elongation of the paper. Although NBKP can obtain strength, due to its long fiber length, there are many fiber-to-fiber bonds and it is difficult to elongate. Compared with NBKP, LBKP has a shorter fiber length and is easier to elongate, but it has water retention ability and has an adverse effect on the transfer efficiency. When the drainage degree is, for example, a small value, the water retention ability and specific surface area of the paper increase. As a result, the affinity for the printing ink increases and it has an adverse effect on the transfer efficiency. If it is a combination of specific amount ranges of LBKP and NBKP within the above drainage degree range, the transfer paper can obtain appropriate elongation ease and does not have an adverse effect on the transfer efficiency. Here, the drainage degree is the CSF drainage degree determined in accordance with ISO5267-2:2001 "Pulps - Determination of drainability - Part 2 "Canadian Standard" freeness method".

[0018] In the coating layer described above, the coating layer located outermost with respect to the base paper is referred to as the outermost coating layer. When there is one coating layer, that coating layer becomes the outermost coating layer. The outermost coating layer contains calcined kaolin as a white inorganic pigment, as well as carboxymethyl cellulose and polyvinyl alcohol as binders. When there are two or more coating layers, the coating layer existing between the base paper and the outermost coating layer is not particularly limited in terms of the type and quantity of the binder, the presence or absence, type, and quantity of the white inorganic pigment, and the presence or absence and quantity of other conventionally known additives. In some embodiments, there is one coating layer. This is because the manufacturing cost of the transfer paper is advantageous. Also, the coating layer may be provided on one side or both sides of the base paper. When the transfer paper has the outermost coating layer according to the present invention on one side of the base paper, for example, for the purpose of preventing curling of the paper, it may have a conventionally known backcoat layer on the back surface of the base paper.

[0019] The coating layer including the outermost coating layer can be obtained by applying and drying the coating layer coating liquid to the base paper or the coating layer using a conventionally known coating device and drying device. Examples of conventionally known coating devices include size press, gate roll coater, film transfer coater, blade coater, rod coater, air knife coater, gravure coater, bar coater, E bar coater, curtain coater, etc. Examples of conventionally known drying devices include various drying devices such as hot air dryers like straight tunnel dryers, arch dryers, air loop dryers, sine curve air float dryers, infrared heating dryers, and dryers using microwaves, etc. After applying and drying the coating layer coating liquid, a calendering treatment can be performed on the coating layer.

[0020] In some embodiments, the coating amount of the coating layer is 2 g / m per side of the base paper in terms of dry solid content 2 or more and 6 g / m 2 or less. This is because the property of being able to adhere well to the object to be printed is improved.

[0021] Fired kaolin is mainly composed of kaolin minerals such as kaolinite. For example, it is obtained by firing kaolinite or pyrophyllite. Fired kaolin can be obtained by various known manufacturing methods. The fired kaolin used, for example, includes dehydroxylated kaolin generated by firing kaolinite at a temperature of about 650°C to 700°C, that is, partially fired kaolin, and fully fired kaolin obtained by firing kaolinite at about 1000°C to 1050°C. The fired kaolin used includes those that maintain the hexagonal plate shape with the particle shape unchanged before firing, and those that have lost structural water and are partially or entirely amorphous. In some embodiments, the fired kaolin has a cumulative frequency of 60% by mass or more with a particle diameter of 2 μm or less in the volume-based particle size distribution. In at least one embodiment, the fired kaolin has a cumulative frequency of 60% by mass or more with a particle diameter of 2 μm or less in the volume-based particle size distribution and a specific surface area of 15 m 2 / g or more and 20 m 2 / g or less. These are because the barrier property is improved during transfer.

[0022] The outermost coating layer can contain a white inorganic pigment other than fired kaolin as long as it does not inhibit the effects of the present invention. In some embodiments, the content of the white inorganic pigment other than fired kaolin in the outermost coating layer is 10 parts by mass or less with respect to 100 parts by mass of the white inorganic pigment including fired kaolin in the outermost coating layer. The white inorganic pigment is a conventionally known one in the field of coated paper. Examples of the white inorganic pigment include various kaolins excluding fired kaolin, heavy calcium carbonate, light calcium carbonate, talc, satin white, lithopone, titanium oxide, zinc oxide, amorphous silica, colloidal silica, alumina, aluminum hydroxide, zinc oxide, activated clay, and diatomaceous earth.

[0023] Carboxymethyl cellulose is a type of cellulose ether, which is a conventionally known one and is not particularly limited. Carboxymethyl cellulose contains an alkali metal salt. Carboxymethyl cellulose can be obtained, for example, by reacting pulp as a raw material with sodium monochloroacetate and sodium hydroxide (direct method). In addition to the direct method, it can also be obtained by the Alsell method and the solvent method. Carboxymethyl cellulose can be produced in various molecular weights or degrees of polymerization depending on the properties of the pulp used and the manufacturing method. Generally, carboxymethyl cellulose is industrially produced and sold as an alkali metal salt of carboxymethyl cellulose. Carboxymethyl cellulose is mostly sodium carboxymethyl cellulose or potassium carboxymethyl cellulose. Conventionally, the description of sodium or potassium is often omitted. In at least one embodiment, carboxymethyl cellulose is sodium carboxymethyl cellulose. This is because sodium carboxymethyl cellulose is easily commercially available. Carboxymethyl cellulose is commercially available, for example, from Sigma-Aldrich, Daicel Mirais Co., Ltd., Daiichi Kogyo Seiyaku Co., Ltd., CP Kelco, Nippon Paper Industries Co., Ltd., and Ashland, etc.

[0024] In some embodiments, carboxymethyl cellulose is a low molecular weight type with a weight average molecular weight less than 1,000,000 in terms of polyethylene glycol obtained by gel permeation chromatography (GPC). In some embodiments, carboxymethyl cellulose has a weight average molecular weight of 770,000 or less. Also, in some embodiments, carboxymethyl cellulose has a weight average molecular weight of 27,000 or more. Further, in at least one embodiment, carboxymethyl cellulose has a weight average molecular weight of 27,000 or more and 770,000 or less. This is because the transcription efficiency is improved. In some embodiments, the degree of etherification of carboxymethyl cellulose is 0.6 or more and 1.27 or less. This is because the property of being able to adhere well to the object to be printed is improved. The degree of etherification refers to the number (average value) of hydroxyl groups substituted with carboxymethyl groups among the three hydroxyl groups on the glucose ring constituting cellulose. The degree of etherification can theoretically have a value between 0 and 3, and generally, the higher the degree of substitution, the more hydrophilic it becomes. In at least one embodiment, the carboxymethyl cellulose has a weight average molecular weight in terms of polyethylene glycol obtained by gel permeation chromatography (GPC) of 27,000 or more and 770,000 or less, and a degree of etherification of 0.6 or more and 1.27 or less.

[0025] Polyvinyl alcohol refers to a general term including general polyvinyl alcohol and various modified polyvinyl alcohols. Polyvinyl alcohol is a conventionally known polyvinyl alcohol and its various modified polyvinyl alcohols. Examples of polyvinyl alcohol include polyvinyl alcohols with various degrees of saponification and various average polymerization degrees, modified polyvinyl alcohols into which various functional groups such as silyl groups, carboxyl groups, amino groups, and acetoacetyl groups are introduced, and modified polyvinyl alcohols into which other monomers such as ethylene are introduced randomly, graftedly, or blockwise. In some embodiments, polyvinyl alcohol is one or more selected from the group consisting of polyvinyl alcohols with various degrees of saponification and various average polymerization degrees and modified polyvinyl alcohols. Polyvinyl alcohol is commercially available from companies such as Mitsubishi Chemical Corporation, Kuraray Co., Ltd., Nippon Synthetic Chemical Industry Co., Ltd., and Denka Co., Ltd.

[0026] In at least one embodiment, the polyvinyl alcohol is a carboxyl group-modified polyvinyl alcohol. The reason is that it has excellent adhesion to the object to be printed, heat resistance, and / or improved barrier properties during transfer. The carboxyl group-modified polyvinyl alcohol is a polyvinyl alcohol having a site where a carboxyl group is introduced and carboxylated to form a carboxylic acid. Examples of the carboxyl group-modified polyvinyl alcohol include those obtained by graft polymerization or block polymerization of polyvinyl alcohol and a vinyl carboxylic acid compound, those obtained by copolymerizing a vinyl ester compound and a vinyl carboxylic acid compound and then saponifying, and those obtained by reacting polyvinyl alcohol with a carboxylating agent. Examples of the vinyl carboxylic acid compound include (meth)acrylic acid, (anhydrous) maleic acid, (anhydrous) phthalic acid, and (anhydrous) itaconic acid, which are (anhydrous) carboxyl group-containing compounds. Examples of the vinyl ester compound include vinyl acetate, vinyl formate, vinyl propionate, vinyl versatate, and vinyl valerate. Examples of the carboxylating agent include succinic anhydride, maleic anhydride, acetic anhydride, trimellitic anhydride, phthalic anhydride, pyromellitic anhydride, glutaric anhydride, hydrogenated phthalic anhydride, and naphthalenedicarboxylic anhydride. In some embodiments, the carboxyl group-modified polyvinyl alcohol has an average degree of polymerization of 200 or more and 3000 or less. Also, in some embodiments, the carboxyl group-modified polyvinyl alcohol has a saponification degree of 80 mol% or more and 90 mol% or less. In at least one embodiment, the carboxyl group-modified polyvinyl alcohol has an average degree of polymerization of 200 or more and 3000 or less and a saponification degree of 80 mol% or more and 90 mol% or less. The reason for this is that it has excellent compatibility with carboxymethyl cellulose.

[0027] In some embodiments, the mass ratio of carboxymethyl cellulose to polyvinyl alcohol in the outermost coating layer is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of carboxymethyl cellulose in the outermost coating layer. In at least one embodiment, the mass ratio of carboxymethyl cellulose to polyvinyl alcohol in the outermost coating layer is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of carboxymethyl cellulose in the outermost coating layer, and further the polyvinyl alcohol is a carboxyl group-modified polyvinyl alcohol. These are because of the characteristics of being able to adhere well to the object to be printed and / or the improvement of heat resistance.

[0028] The outermost coating layer can contain conventionally known binders in addition to carboxymethyl cellulose and polyvinyl alcohol. Conventionally known binders include, for example, starches such as starch, modified starch and denatured starch, celluloses such as hydroxyethyl cellulose excluding carboxymethyl cellulose, natural resins or their derivatives such as casein, gelatin, soy protein, pullulan, gum arabic, gum karaya, albumin, binders such as polyvinyl pyrrolidone, polyacrylamide, polyethyleneimine, polypropylene glycol, polyethylene glycol, maleic anhydride resin, (meth)acrylic acid resin, (meth)acrylic acid ester resin, (meth)acrylic acid ester-butadiene copolymer, styrene-butadiene copolymer and ethylene-vinyl acetate copolymer, and functional group-modified copolymer resins obtained by functional group-containing monomers such as carboxyl groups of various copolymers thereof, thermosetting synthetic resins such as melamine resin and urea resin, polyurethane resin, unsaturated polyester resin, polyvinyl butyral, alkyd resin latex and the like. In some embodiments, in the outermost coating layer, the total of carboxymethyl cellulose and polyvinyl alcohol is 80 parts by mass or more with respect to 100 parts by mass of the binder in the outermost coating layer. In at least one embodiment, the outermost coating layer does not contain any conventionally known binders other than carboxymethyl cellulose and polyvinyl alcohol.

[0029] Although the white inorganic pigment contributes to heat resistance, it adsorbs carboxymethyl cellulose and polyvinyl alcohol, thereby reducing the flexibility of the outermost coating layer. As a result, the transfer paper deteriorates in the property of being able to adhere well to the object to be printed. Also, for example, the white inorganic pigment easily adsorbs the coloring material in the printing ink. As a result, the transfer paper deteriorates in transfer efficiency. When the white inorganic pigment is calcined kaolin, the calcined kaolin does not inhibit the property of being able to adhere well to the object to be printed and the transfer efficiency with respect to the transfer paper having a coating layer containing carboxymethyl cellulose and polyvinyl alcohol. As a result, the transfer paper has the property of being able to adhere well to the object to be printed and has good transfer efficiency. The reason for this is unclear. The inventors consider that it is due to the change in polarity and the amorphization of the calcined kaolin. Furthermore, the inventors have found that when the outermost coating layer contains carboxymethyl cellulose, polyvinyl alcohol, and calcined kaolin, the transfer paper has heat resistance and barrier properties during transfer. The reason for this is unclear. The inventors consider that it is a synergistic effect of carboxymethyl cellulose having a high heat resistance temperature and polyvinyl alcohol having a high crystallinity, and calcined kaolin.

[0030] In some embodiments, in the outermost coating layer, the calcined kaolin is 30 parts by mass or more and 90 parts by mass or less with respect to 1000 parts by mass in total of carboxymethyl cellulose and polyvinyl alcohol. This is because the heat resistance and the barrier property during transfer are improved.

[0031] The outermost coating layer can contain various additives conventionally known in the field of coated paper as required. Examples of the additives include a dispersant, a fixing agent, a thickener, a fluidity improver, an antifoaming agent, a release agent, a foaming agent, a penetrant, a colorant, a printing suitability improver, a fluorescent brightening agent, an ultraviolet absorber, an antioxidant, a preservative, an antibacterial agent, and the like. In addition, the outermost coating layer can contain various auxiliary agents conventionally known in the transfer printing method. The auxiliary agents are added to optimize various physical properties of the coating liquid of the coating layer or to improve the dyeing property of a coloring material contained in a transfer ink such as a sublimation transfer ink. Examples of the auxiliary agents include various surfactants, a moisturizing agent, a wetting agent, a pH adjuster, an alkaline agent, a deepening agent, a degassing agent, and an anti-reduction agent.

[0032] The transfer paper can be obtained by printing a pattern on the side having the outermost coating layer of the transfer paper using various conventionally known printing methods including a transfer ink such as a sublimation transfer ink. The various printing methods for printing a pattern on the transfer paper are conventionally known printing methods and are not particularly limited. Examples of the printing methods include a gravure printing method, an inkjet printing method, an electrophotographic printing method, and a screen printing method. In at least one embodiment, the printing method for printing a pattern on the transfer paper is an inkjet printing method.

[0033] The transfer printing method is a method having a step of printing a pattern on the transfer paper to obtain a transfer paper and a step of bringing the surface of the transfer paper on which the pattern is printed into close contact with the object to be printed. The step of bringing into close contact includes heating or heating and pressurizing as required. Each condition of heating and pressurizing in the step of bringing into close contact is a condition conventionally known in the transfer printing method. Examples of the step of bringing into close contact include a method of bringing the transfer paper into close contact with the object to be printed by a press or a heating drum and heating or heating and pressurizing. In at least one embodiment, the transfer ink of the transfer printing method is a sublimation transfer ink.

[0034] The material to be printed is a fiber material and is not particularly limited. The fiber material may be either a natural fiber material or a synthetic fiber material. Examples of the natural fiber material include cellulose-based fiber materials such as cotton, hemp, lyocell, rayon, and acetate, and protein-based fiber materials such as silk, wool, and animal hair. Examples of the synthetic fiber material include polyamide fiber (nylon), vinylon, polyester, and polyacrylic. In at least one embodiment, when using sublimation transfer printing ink, the fiber material is polyester. Further, if necessary, the material to be printed may be pretreated with a chemical agent or the like that is effective for promoting dyeing.

Example

[0035] Hereinafter, the present invention will be described in more detail by way of examples. It should be noted that the present invention is not limited to these examples. Here, "parts by mass" and "mass%" represent "parts by mass" and "mass%", respectively, of the dry solid content or the substantial component amount. The application amount of the coating layer represents the dry solid content.

[0036] (Base paper) To a pulp slurry in which a total of 1000 parts by mass of LBKP and NBKP whose drainage was adjusted by beating was dispersed in water, 25 parts by mass of talc and 50 parts by mass of light calcium carbonate as fillers, 10 parts by mass of cationized starch, 9 parts by mass of aluminum sulfate, and 0.7 parts by mass of an alkyl ketene dimer type sizing agent were added, and the paper was made by a Fourdrinier paper machine to obtain a sheet paper. The obtained sheet paper was subjected to a machine calendering treatment to obtain a calendered sheet paper. The density of the paper thus obtained was 0.81 g / cm 3 Oxidized starch was applied to both sides of the calendered sheet paper using a size press so that the coating amount per side was 1 g / m 2 to prepare a base paper. The drainage of each of LBKP and NBKP and the content of each of LBKP and NBKP in 1000 parts by mass are shown in Tables 1 to 3. Here, the drainage is the CSF drainage and was determined according to ISO 5267-2:2001.

[0037] (Coating liquid for the outermost coating layer) The coating liquid for the coating layer was prepared according to the following content. The parts by mass of cellulose are listed in Tables 1 to 3. The parts by mass of polyvinyl alcohol are listed in Tables 1 to 3. The parts by mass of the white inorganic pigment are listed in Tables 1 to 3. They were compounded according to the above content, mixed and dispersed with water, and adjusted to a concentration of 10% by mass.

[0038] The materials used in the coating liquid for the outermost coating layer are as follows. As cellulose, commercially available carboxymethyl cellulose (weight average molecular weight 260,000, degree of etherification 0.7) was used for Ce1, and commercially available hydroxymethyl cellulose was used for Ce2. As polyvinyl alcohol, commercially available polyvinyl alcohol (saponification degree 88 mol%, number average degree of polymerization 300) was used for Po1, and commercially available carboxyl group-modified polyvinyl alcohol (saponification degree 86 mol%, number average degree of polymerization 300) was used for Po2. As the white inorganic pigment, commercially available calcined kaolin was used for Pg1, commercially available primary kaolin was used for Pg2, and commercially available synthetic amorphous silica (average particle diameter 2.3 μm, aggregated particles) was used for Pg3.

[0039] (Transfer paper) The transfer paper was produced according to the following procedure. The coating liquid for the outermost coating layer was applied to one side of the base paper using an air knife coater and dried using a hot air dryer. After drying, a calendering treatment was performed to obtain the transfer paper. The coating amount was 4 g / m 2 as such.

[0040] [Table 1]

[0041] [Table 2]

[0042] [Table 3]

[0043] (Transfer paper) Using an inkjet printer (JV2-130II, manufactured by Mimaki Engineering Co., Ltd.) that uses sublimation dye ink, on the obtained transfer paper, each single color of sublimation dye ink (cyan, magenta, yellow, black), as well as green which is a mixed color of yellow and cyan, red which is a mixed color of yellow and magenta, blue which is a mixed color of cyan and magenta, and black which is a mixed color of yellow, cyan, and magenta, were printed to obtain an evaluation pattern, and transfer paper was obtained.

[0044] (Transfer dyeing) As the printed object, a white polyester cloth was used. The side of the transfer paper having the coating layer was opposed to and adhered closely to the white polyester cloth. The transfer paper with the white polyester cloth adhered was heated at a temperature of 190 °C for 30 to 60 seconds using a heat transfer press (INSTA, USA, Heat Press Model 204).

[0045] (Characteristic of being able to adhere well to the printed object (adhesion)) In the examples, the characteristic of being able to adhere well to the printed object is referred to as "adhesion". Adhesion was visually observed from the viewpoints of the sharpness reduction and distortion of the pattern generated due to the positional deviation of the transfer paper with respect to the printed object on which the pattern was formed with the transfer dyeing time being 45 seconds, and the adhesion was evaluated according to the following criteria. In the present invention, the transfer paper is considered to have adhesion if the evaluation is 2, 3, or 4. 4: There is no sharpness reduction and distortion, and it is extremely good. 3: The sharpness reduction and / or distortion are extremely slight, and it is good. 2: The sharpness reduction and / or distortion are slight, and it is generally good. 1: Inferior to the above 2, and sharpness reduction and / or distortion are recognized.

[0046] (Transfer efficiency) The heating time during transfer printing was changed, and the color density of the pattern on the white polyester with the pattern formed was visually observed and evaluated according to the following criteria. The heating times were 30 seconds, 45 seconds, and 60 seconds. In the present invention, if the evaluation of the transfer paper is 3 to 5, it is considered that the transfer efficiency is good. 5: There is no change in color density at 30 seconds, 45 seconds, and 60 seconds. 4: A very slight change in color density is observed between 30 seconds and 45 seconds. 45 seconds and 60 seconds: No change in color density is observed. 3: A slight change in color density is observed between 30 seconds and 45 seconds. 45 seconds and 60 seconds: No change in color density is observed. 2: A slight change in color density is observed between 45 seconds and 60 seconds. 1: A change in color density is observed between 45 seconds and 60 seconds.

[0047] (Heat resistance) For the printed matter with the pattern formed, the lines appearing along the original contour of the pattern generated by the heat shrinkage of the coating layer of the transfer paper were visually observed, and the heat resistance was evaluated according to the following criteria. In the present invention, if the evaluation of the transfer paper is 2, 3, or 4, it is considered to have heat resistance. 4: There are no lines along the contour of the pattern, which is extremely good. 3: A very thin line along the contour of the pattern is barely visible, which is good. 2: A very thin line along the contour of the pattern is slightly visible, which is generally good. 1: Inferior to the above 2, and a very thin line is visible along the contour of the pattern.

[0048] (Barrier property during transfer) In the transfer paper peeled from the printed matter after transfer, the degree of the pattern visually observed from the back surface of the transfer paper (the surface opposite to the side in close contact with the printed matter) was observed, and the barrier property during transfer was evaluated according to the following criteria. In the present invention, if the evaluation of the transfer paper is 3 or 4, it is considered to have the barrier property during transfer. 4: The pattern is hardly visible. 3: The pattern is slightly visible. 2: The pattern is somewhat visible. 1: Inferior to the above 2, the pattern is visible.

[0049] Each evaluation result is described in Tables 1 to 3.

[0050] From the evaluation results in Tables 1 to 3, it can be seen that the transfer papers of Examples 1 to 23 corresponding to the present invention have the characteristics of being able to adhere well to the object to be printed, having good transfer efficiency, having heat resistance, and having barrier properties during transfer. On the other hand, it can be seen that the transfer papers of Comparative Examples 1 to 6 that do not satisfy the configuration of the present invention cannot satisfy at least one of the effects according to the present invention. Mainly, from the comparison between Examples 1 to 5 and the comparison between Examples 6 to 10, it can be seen that in the outermost coating layer, when the content mass ratio of carboxymethyl cellulose and polyvinyl alcohol is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of carboxymethyl cellulose, the transfer paper has improved adhesion and / or heat resistance. Mainly, from the comparison between Examples 1 to 5 and Examples 6 to 10, it can be seen that when the polyvinyl alcohol is carboxyl group-modified polyvinyl alcohol, the transfer paper has improved adhesion, heat resistance, and / or barrier properties during transfer.

[0051] Regarding the above-described embodiments of the present invention, the following additional notes are further disclosed.

[0052] <1> A transfer paper having a base paper and one layer or two or more coating layers on at least one side of the base paper, wherein the outermost coating layer located outermost with respect to the base paper contains calcined kaolin, carboxymethyl cellulose, and polyvinyl alcohol, and is used in a transfer printing method using printing ink.

[0053] <2> The transfer paper according to <1> above, wherein in the outermost coating layer, the content mass ratio of the carboxymethyl cellulose and the polyvinyl alcohol is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the carboxymethyl cellulose.

[0054] <3> The transfer paper according to the above <1> or <2>, wherein the polyvinyl alcohol is a carboxyl group-modified polyvinyl alcohol.

[0055] <4> The transfer paper according to the above <1> or <3>, wherein the carboxymethyl cellulose has a weight average molecular weight in terms of polyethylene glycol of 27,000 or more and 770,000 or less obtained by gel permeation chromatography (GPC), and an etherification degree of 0.6 or more and 1.27 or less.

[0056] <5> The transfer paper according to the above <1>, wherein the base paper contains pulp, and the pulp in the base paper has 75% by mass or more and 95% by mass or less of LBKP having a drainage degree in the range of 380 ml or more and 480 ml or less with respect to the pulp in the base paper, and 5% by mass or more and 25% by mass or less of NBKP having a drainage degree in the range of 400 ml or more and 480 ml or less.

[0057] <6> The transfer paper according to the above <3>, wherein the base paper contains pulp, and the pulp in the base paper has 75% by mass or more and 95% by mass or less of LBKP having a drainage degree in the range of 380 ml or more and 480 ml or less with respect to the pulp in the base paper, and 5% by mass or more and 25% by mass or less of NBKP having a drainage degree in the range of 400 ml or more and 480 ml or less.

[0058] <7> The transfer paper according to the above <4>, wherein the base paper contains pulp, and the pulp in the base paper has 75% by mass or more and 95% by mass or less of LBKP having a drainage degree in the range of 380 ml or more and 480 ml or less with respect to the pulp in the base paper, and 5% by mass or more and 25% by mass or less of NBKP having a drainage degree in the range of 400 ml or more and 480 ml or less.

Claims

1. It has a base paper and one or more coating layers on at least one side of the base paper, The outermost coating layer located outermost with respect to the base paper contains calcined kaolin, carboxymethyl cellulose, and polyvinyl alcohol, The content of white inorganic pigments other than calcined kaolin in the outermost coating layer is 10 parts by mass or less with respect to 100 parts by mass of white inorganic pigments including calcined kaolin in the outermost coating layer, A transfer paper for use in the transfer printing method.

2. The transfer paper according to claim 1, wherein in the outermost coating layer, the mass ratio of the carboxymethyl cellulose to the polyvinyl alcohol is such that the polyvinyl alcohol is 90 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of carboxymethyl cellulose.

3. The transfer paper according to claim 1 or 2, wherein the polyvinyl alcohol is a carboxyl group-modified polyvinyl alcohol.

4. The transfer paper according to any one of claims 1 to 3, wherein the white inorganic pigment other than the calcined kaolin is selected from the group consisting of various kaolins excluding calcined kaolin, heavy calcium carbonate, light calcium carbonate, talc, satin white, lithopone, titanium oxide, zinc oxide, amorphous silica, colloidal silica, alumina, aluminum hydroxide, zinc oxide, activated clay, and diatomaceous earth.

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