JP2008254386A - Manufacturing method for thermal transfer image-receiving sheet and coating liquid for forming thermal transfer image-receiving sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a thermal transfer image-receiving sheet that enables to simultaneously form a plurality of layers including a porous layer without mixing them with each other. <P>SOLUTION: The manufacturing method for a thermal transfer image-receiving sheet has a simultaneous multilayer coating step, in which an aqueous coating liquid containing hollow particles and a cooling gelatinizer in order to form a porous layer is used for simultaneously coating a plurality of layers including a porous layer on a base-material sheet, and a cooling step for forcibly cooling a multilayer coating film formed on the base-material sheet in the simultaneous multilayer coating step. A viscosity of the coating liquid for forming a porous layer is within the range of 5-300 mPa s at 40°C and within the range of 0.5-15 Pa s at 20°C. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a thermal transfer image receiving sheet used for printing by a sublimation thermal transfer system, and a thermal transfer image receiving sheet forming coating solution used therefor.

  Conventionally, as a method of forming an image using thermal transfer, a thermal transfer sheet in which a thermal diffusion dye (sublimation dye) as a recording material is carried on a base sheet such as a plastic film, and another paper or plastic film There is known a thermal diffusion transfer system (sublimation thermal transfer system) in which a thermal transfer image receiving sheet provided with a receiving layer on a base sheet is superposed on each other to form a full color image. Since this method uses a thermal diffusion dye as a color material, the density and gradation can be freely adjusted in dot units, and a full-color image exactly as the original can be clearly displayed on the image receiving sheet. It is applied to color image formation for computers and the like. The image is evaluated to be of high quality comparable to a silver salt photograph.

  As a method for producing the thermal transfer image receiving sheet, a method in which a porous layer and a receiving layer are sequentially formed on a substrate sheet by gravure coating or the like has been used. However, since this method is a method of sequentially forming each layer, there is a problem that the number of steps increases. Therefore, in order to produce a thermal transfer image receiving sheet with a smaller number of steps, a method of simultaneously forming a plurality of layers has attracted attention.

  For example, Patent Document 1 discloses a thermal transfer image receiving sheet formed by simultaneously applying a plurality of layers such as a heat insulating layer and a receiving layer on a base material. Specifically, it is described that a thermal transfer image receiving sheet was obtained by using a slide coating method as a simultaneous multi-layer coating method (Example: Production of thermal transfer image receiving sheet 5). Patent Document 2 discloses a method for producing a thermal transfer image-receiving sheet in which an aqueous intermediate layer and an aqueous receiving layer are simultaneously applied (Claim 1). Further, Patent Document 3 discloses a water-soluble image-receiving sheet. An ink jet recording medium having an adhesive resin as the outermost layer is disclosed (claim 1), and it describes the simultaneous application of a coating solution for an ink receiving layer and a basic solution.

  As described above, the method for producing a thermal transfer image-receiving sheet by forming a plurality of layers simultaneously has a very advantageous aspect in terms of production efficiency and production cost. However, on the other hand, there is a problem that it is difficult to form the layers uniformly without mixing them. For example, in the slide coating method, it is necessary to apply the coating liquid constituting each layer on the base sheet in a state where the coating liquid is stacked on the top and bottom, but if the viscosity and surface tension of each coating liquid are not appropriate, There is a problem that mixing and repelling occur between the coating liquids, and the film thickness of each layer cannot be kept uniform.

JP 2006-88691 A JP-A-6-171240 JP 2006-103040 A

  The present invention has been made in view of such problems, and a method for producing a thermal transfer image receiving sheet capable of simultaneously forming a plurality of layers including a porous layer on a substrate sheet without mixing each other. The main purpose is to provide

  In order to solve the above problems, the present invention uses an aqueous porous layer forming coating solution containing hollow particles and a cooling gelling agent, and simultaneously applies a plurality of layers including a porous layer on a substrate sheet. In the simultaneous multilayer coating step and the simultaneous multilayer coating step, a coating film composed of a plurality of layers formed on the base sheet (hereinafter sometimes simply referred to as “multilayer coating film”) is forcibly cooled. A method for producing a thermal transfer image-receiving sheet having a cooling treatment step, wherein the viscosity of the porous layer-forming coating liquid is in the range of 5 mPa · s to 300 mPa · s at 40 ° C., and at 20 ° C. Provided is a method for producing a thermal transfer image-receiving sheet, which is within a range of 0.5 Pa · s to 15 Pa · s.

According to the present invention, when the viscosity of the coating liquid for forming a porous layer is within a range of 5 mPa · s to 300 mPa · s at 40 ° C., the coating liquid for forming a porous layer in the simultaneous multilayer coating step. Can be uniformly coated on the base material sheet.
Moreover, when the viscosity of the coating liquid for forming the porous layer is within a range of 0.5 Pa · s to 15 Pa · s at 20 ° C., the porous layer and the porous layer are formed in the cooling treatment step. Mixing with other adjacent layers can be prevented.
For this reason, according to the present invention, a plurality of layers including a porous layer can be formed simultaneously without being mixed with each other.

  In the present invention, the simultaneous multilayer coating step uses an aqueous receptive layer forming coating solution containing a receptive layer forming resin and a cooling gelling agent, on the base sheet, the porous layer, You may apply | coat simultaneously the receiving layer arrange | positioned on a porous layer. This is because the simultaneous multilayer coating step forms the receiving layer at the same time, so that the thermal transfer image receiving sheet can be produced with fewer steps.

  In the present invention, the cooling gelling agent is preferably gelatin. Since gelatin has the property of partially recovering the triple helix structure upon cooling and gelling, by using such gelatin as the cooling gelling agent, the coating liquid for forming a porous layer is obtained. This is because it becomes easy to impart predetermined viscosity characteristics to the above.

  In addition, the present invention contains a cooling gelling agent and an aqueous solvent, has a viscosity in the range of 1 mPa · s to 300 mPa · s at 40 ° C., and 0.01 Pa · s to 15 Pa · s at 20 ° C. The coating liquid for forming a thermal transfer image-receiving sheet is provided.

  According to the present invention, since it contains a cooling gelling agent and the viscosity is within the above range, it exhibits a relatively low viscosity at a high temperature and a relatively high viscosity at a low temperature. For example, by using a method for producing a thermal transfer image-receiving sheet having a simultaneous multilayer coating step and a cooling gelation step, such as the method for producing a thermal transfer image-receiving sheet of the present invention, a plurality of layers can be bonded to each other on a substrate sheet. It becomes possible to form simultaneously without mixing. For this reason, according to the coating liquid for forming a thermal transfer image receiving sheet of the present invention, a thermal transfer image receiving sheet can be formed with high efficiency.

  The method for producing a thermal transfer image-receiving sheet of the present invention can form a plurality of layers including a porous layer on a substrate sheet at the same time without mixing with each other. There is an effect that can be done.

The present invention relates to a method for producing a thermal transfer image receiving sheet and a coating liquid for forming a thermal transfer image receiving sheet.
Hereinafter, the manufacturing method of the thermal transfer image receiving sheet of the present invention and the coating solution for forming the thermal transfer image receiving sheet will be described in order.

A. First, a method for producing a thermal transfer image receiving sheet of the present invention will be described. The method for producing a thermal transfer image-receiving sheet of the present invention uses a water-based porous layer forming coating solution containing hollow particles and a cooling gelling agent, and simultaneously coats a plurality of layers including a porous layer on a substrate sheet. A simultaneous multilayer coating step and a cooling treatment step for forcibly cooling the multilayer coating film formed on the substrate sheet in the simultaneous multilayer coating step, wherein the viscosity of the coating liquid for forming the porous layer is , Within a range of 5 mPa · s to 300 mPa · s at 40 ° C. and within a range of 0.5 Pa · s to 15 Pa · s at 20 ° C.

A method for producing such a thermal transfer image receiving sheet of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing an example of a method for producing a thermal transfer image receiving sheet of the present invention. As illustrated in FIG. 1, the method for producing a thermal transfer image receiving sheet of the present invention uses a base sheet 1 (FIG. 1A), and includes hollow particles and a cooling gelling agent on the base sheet 1. By simultaneously applying a coating solution for forming a porous layer and a coating solution for forming a receiving layer containing a resin for forming a receiving layer and a cooling gelling agent, the porous layer 21 and the receiving layer are formed on the substrate sheet 1. 22 and a simultaneous multilayer coating process for forming a multilayer coating film 2 laminated in this order (FIG. 1 (b)), a cooling treatment process for forcibly cooling the multilayer coating film 2 (FIG. 1 (c)), And a thermal transfer image-receiving sheet 10 having a structure in which a multilayer coating film 2 composed of a porous layer 21 and a receiving layer 22 is formed on the substrate sheet 1 is produced (FIG. 1 (d). )).
In such an example, the method for producing a thermal transfer image-receiving sheet of the present invention is such that the viscosity of the coating liquid for forming a porous layer used in the simultaneous multilayer coating step (FIG. 1B) is 5 mPa · s at 40 ° C. It is in the range of ˜300 mPa · s and in the range of 0.5 Pa · s to 15 Pa · s at 20 ° C.

According to the present invention, the viscosity of the coating liquid for forming a porous layer is within the range of 5 mPa · s to 300 mPa · s at 40 ° C., so that the coating liquid for forming a porous layer is used in the simultaneous multilayer coating step. Can be uniformly coated on the base material sheet.
Further, when the viscosity of the coating liquid for forming a porous layer is within a range of 0.5 Pa · s to 15 Pa · s at 20 ° C., the porous layer and the porous layer are formed in the cooling treatment step. Mixing with other adjacent layers can be prevented.
For this reason, according to the present invention, a plurality of layers including a porous layer can be formed simultaneously without being mixed with each other.

The method for producing a thermal transfer image-receiving sheet of the present invention includes at least a simultaneous multilayer coating process and a cooling process, and any other process may be used as necessary.
Hereafter, each process used for this invention is demonstrated in detail.

1. Simultaneous multilayer coating process First, the simultaneous multilayer coating process used in the present invention will be described. This step is a step of simultaneously applying a plurality of layers including a porous layer on a base sheet using an aqueous porous layer forming coating solution containing hollow particles and a cooling gelling agent.
Hereinafter, such a simultaneous multilayer coating process will be described in detail.

(1) Porous layer forming coating solution First, the porous layer forming coating solution used in this step will be described. The coating liquid for forming a porous layer used in this step contains at least hollow particles and a cooling gelling agent, and these are dispersed and dissolved in an aqueous solvent. Moreover, the viscosity of the coating liquid for forming a porous layer used in this step is in the range of 5 mPa · s to 300 mPa · s at 40 ° C. and 0.5 Pa · s to 15 Pa · s at 20 ° C. It is characterized by being within the range.

The reason why the viscosity of the coating liquid for forming a porous layer used in this step is defined within the above range is as follows. That is, when the viscosity at 40 ° C. is outside the above range, streaks, unevenness, etc. occur when the porous layer forming coating solution is applied on the base sheet in this step, and the coating quality is low. Although it will be damaged, it becomes possible to apply uniformly by being in the said range. Here, the viscosity at 40 ° C. of the coating liquid for forming a porous layer is not particularly limited as long as it is within the above range, but in particular, it is in the range of 1 mPa · s to 50 mPa · s. It is particularly preferable that it is in the range of 5 mPa · s to 40 mPa · s.
Further, if the viscosity at 20 ° C. is outside the above range, the viscosity of the porous layer formed in this step in the cooling treatment step described later becomes insufficient, and other layers adjacent to the porous layer are mixed. However, there is no such problem as long as it is within the above range. Here, the viscosity at 20 ° C. of the coating liquid for forming a porous layer is not particularly limited as long as it is within the above range, but it is in the range of 0.5 Pa · s to 10 Pa · s. In particular, it is preferably in the range of 1 Pa · s to 7 Pa · s.

  The viscosity can be measured, for example, using a tuning fork type vibration viscometer SV-10 manufactured by A & D.

  The viscosity of the porous layer forming coating solution used in this step can be adjusted within the above range by arbitrarily adjusting the composition of the porous layer forming coating solution. It can be easily adjusted by changing the kind and content of the cooling gelling agent contained in the coating solution for forming a layer.

  The cooling gelling agent used in this step has a property of gelling by being cooled, and is particularly limited as long as it can impart the above-described viscosity characteristics to the porous layer forming coating liquid. Is not to be done.

  Examples of such a cooling gelling agent include gelatin, polyvinyl alcohol, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, pectin and the like.

  Here, the gelatin is composed of a peptide chain obtained by denaturing collagen having a triple helix structure, and partially recovers the triple helix structure by cooling, thereby recovering the recovered triple. By forming a three-dimensional network with a Lix structure as a starting point, it exhibits cooling gelation characteristics.

The polyvinyl alcohol is usually used in combination with Na ₂ B ₄ O _7, by forming a hydrogen bond between the Na ₂ B ₄ O _7, by forming a three-dimensional network as a starting point the hydrogen bond, It shows cooling gelation characteristics.

  The above-mentioned κ-carrageenan, λ-carrageenan, and ι-carrageenan are natural polymer compounds mainly composed of galactose and 3,6-anhydrogalactose having a molecular weight of about 100,000 to 500,000 extracted from red algae seaweed. It is characterized by having a semi-ester type sulfate group in the molecule, and usually exhibits cooling gelation properties when used in combination with a thickener such as locust bean gum or carbonate. .

  The pectin is a natural polysaccharide that constitutes a cell wall of a plant, and exhibits cooling gelation characteristics when used in combination with an ionic compound.

  In this step, any of the above cooling gelling agents can be suitably used. In this step, only one type of cooling gelling agent may be used, or two or more types of cooling gelling agent may be used. Of these, gelatin, polyvinyl alcohol, κ-carrageenan, or pectin is preferably used in this step, and gelatin is particularly preferably used. This is because gelatin exhibits a cooling gelation characteristic by the mechanism as described above, and therefore it is not necessary to use another compound in combination in order to develop the cooling gelation characteristic. Moreover, since it is a material widely used industrially, it is advantageous in terms of availability and is easily applied to the present invention.

  The amount of the cooling gelling agent contained in the porous layer forming coating liquid is within a range in which a predetermined viscosity characteristic can be imparted to the porous layer forming coating liquid, depending on the type of the cooling gelling agent. If it is, it will not specifically limit. Especially in this process, it is preferable that it is 50 mass% or less, It is preferable that it is in the range of 5 mass%-40 mass% especially, Furthermore, it is in the range of 5 mass%-35 mass%. preferable.

The hollow particles used in the coating liquid for forming a porous layer are not particularly limited as long as a porous layer having desired heat insulating properties and cushioning properties can be obtained. Therefore, the hollow particles used in this step may be expanded particles or non-expanded particles. The expanded particles may be independent expanded particles or continuous expanded particles.
Furthermore, the hollow particles used in this step may be organic hollow particles composed of a resin or the like, or may be inorganic hollow particles or porous particles composed of glass or the like. The hollow particles may be cross-linked hollow particles.

  Examples of the resin constituting the hollow particles include styrene resins such as crosslinked styrene-acrylic resins, (meth) acrylic resins such as acrylonitrile-acrylic resins, phenolic resins, fluorine resins, polyamide resins, and polyimide resins. Examples thereof include resins, polycarbonate resins, and polyether resins.

  As an average particle diameter of the said hollow particle, it is preferable that it exists in the range of 0.1 micrometer-15 micrometers, for example, especially in the range of 0.1 micrometer-10 micrometers. This is because if the average particle size is too small, the amount of hollow particles used increases and the cost increases, and if the average particle size is too large, it becomes difficult to form a smooth porous layer.

  The solid content concentration of the hollow particles contained in the porous layer forming coating solution is not particularly limited as long as it is within a range in which a porous layer having desired heat insulating properties and cushioning properties can be obtained. However, it is preferable that it exists in the range of 20 mass%-90 mass%, for example in the range of 40 mass%-80 mass% especially. If the content is too small, voids in the porous layer may be reduced, and sufficient heat insulating properties and cushioning properties may not be obtained. If the content is too large, adhesiveness may be inferior or surface smoothness may be impaired. This is because there is a case.

  The coating liquid for forming a porous layer used in this step is obtained by dispersing and dissolving the cooling gelling agent and the hollow particles in an aqueous solvent. The “aqueous solvent” used in this step is water. Refers to a solvent containing as a main component. The ratio of water in the aqueous solvent is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. Examples of the solvent other than water used in this step include alcohols such as methanol, ethanol, isopropanol and n-propanol; glycols such as ethylene glycol, diethylene glycol and glycerin; esters such as ethyl acetate and propyl acetate; acetone And ketones such as methyl ethyl ketone; amides such as N, N-dimethylformamide.

  The porous layer forming coating solution used in this step may contain other additives other than the hollow particles and the cooling gelling agent. Examples of such other additives include a binder for forming a porous layer, a nonionic silicone-based surfactant, a curing agent such as an isocyanate compound, a wetting agent, and a dispersing agent.

  As the porous layer forming binder, an aqueous resin is usually used. Examples of such water-based resins include polyurethane resins such as acrylic urethane resins, polyester resins, gelatin, polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, pullulan, carboxymethyl cellulose, hydroxyethyl cellulose, dextran, dextrin, and polyacrylic acid. And salts thereof, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, casein, xanthene gum, locust bean gum, alginic acid, gum arabic, and those described in JP-A-7-195826 and 7-9757. Homopolymerization of a real xylene oxide copolymer, water-soluble polyvinyl butyral, or a vinyl monomer having a carboxyl group or a sulfonic acid group described in JP-A-62-245260 And copolymers and the like. Moreover, you may use in combination of 2 or more types of the said resin.

(2) Base material sheet Next, the base material sheet used for this process is demonstrated. The base material sheet used in this step has a function of supporting the multilayer coating film formed in this step.

  The substrate sheet used in this step has a desired heat resistance depending on the printing temperature or the like when forming an image using the thermal transfer image receiving sheet obtained by the thermal transfer image receiving sheet manufacturing method of the present invention. There is no particular limitation as long as it is present. Specific examples of such a base sheet include resin-coated paper, resin film base, and paper base. In particular, it is preferable to use resin-coated paper in this step.

  Resin-coated paper is usually formed by laminating a base resin layer on both sides of a base paper. Examples of the base paper constituting the base paper include natural pulp, synthetic pulp, and pulp paper made from a mixture thereof. Among these, it is preferable to use paper mainly composed of wood pulp. The base paper may be subjected to a conventionally known process such as a calendar process to be described later if necessary.

  The base paper preferably has a thickness in the range of 10 μm to 1000 μm, and more preferably in the range of 50 μm to 300 μm.

  Moreover, although the said base paper can be produced by a well-known method, what was produced by carrying out the calendar process with respect to a base paper is preferable. This is because when a base paper that has been calendered is used for the base paper, the smoothness can be improved and the glossiness of the resulting thermal transfer image-receiving sheet can be enhanced.

  The resin for forming the base resin layer is preferably a resin having a small neck-in and a good drawdown property. For example, a polyolefin resin, a polystyrene resin, a vinyl resin, a polyester resin, an ionomer Resin, nylon, polyurethane and the like can be mentioned, and a polyolefin resin is preferable in that a film excellent in water resistance, strength, gloss and the like can be obtained.

  Examples of the polyolefin resin include high-density polyethylene, medium-density polyethylene, low-density polyethylene, polypropylene, polybutene, and polypentene. Among these, high-density polyethylene, medium-density polyethylene, low-density polyethylene, and polypropylene are preferable, and polypropylene is particularly preferable. Is preferred.

  The base resin layer may be a film or sheet obtained by mixing one or more of the resins, or a film or sheet formed by adding a pigment, a filler or the like to the resin. It may be. Further, the resin may be one obtained by blending an additive such as a modifier to improve adhesiveness. Examples of the modifier include olefin copolymers such as Tuffmer (manufactured by Mitsui Chemicals).

  The resin-coated paper can be produced by a known laminating method such as dry lamination, wet lamination, or extrusion. Each of the above layers can be appropriately subjected to primer treatment or corona discharge treatment on the surface for the purpose of improving interlayer adhesion.

  The total thickness of the resin-coated paper is, for example, preferably in the range of 10 μm to 1000 μm, and more preferably in the range of 50 μm to 300 μm.

  On the other hand, examples of the resin film substrate used in this step include polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, and acrylic. , Polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene-ethylene, tetrafluoro Examples include films made of ethylene-hexafluoropropylene, polychlorotrifluoroethylene, polyvinylidene fluoride, etc. It is possible. In particular, in this step, a film made of polyethylene terephthalate or polypropylene resin can be suitably used.

  The thickness of the resin film substrate is preferably, for example, in the range of 20 μm to 100 μm, more preferably in the range of 25 μm to 60 μm, and particularly preferably in the range of 30 μm to 50 μm.

  Examples of the paper substrate used in this step include condenser paper, glassine paper, sulfuric acid paper, or high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, Examples thereof include cast-coated paper, wallpaper, backing paper, synthetic resin or emulsion-impregnated paper, synthetic rubber latex-impregnated paper, synthetic resin-added paper, paperboard, and cellulose fiber paper.

  The thickness of the paper substrate is preferably, for example, in the range of 80 μm to 200 μm, in particular in the range of 100 μm to 180 μm, particularly in the range of 120 μm to 160 μm.

(3) Simultaneous multilayer coating method Next, a method for simultaneously coating a porous layer and a plurality of layers including the porous layer on the substrate sheet using the porous layer forming coating solution will be described.

  In this step, the method of simultaneously applying a plurality of layers including a porous layer on the substrate sheet is not particularly limited as long as each layer can be applied with a uniform thickness without intermingling the layers. It is not a thing. In particular, in this step, a slide coating method is generally used in which the coating liquid for forming each layer is slid and applied in a state where the layers are vertically stacked.

  Here, with the slide coating method, for example, as shown in FIG. 2, the plurality of coating liquids 11 to 13 constituting each layer of the thermal transfer image receiving sheet are wound around the back roll 14 while being stacked one above the other. This is a method of applying to the base sheet 15. From the viewpoint of coating quality, the slide coating method is excellent in film thickness uniformity, and since there is no rotating part, quality defects due to scattering of the coating liquid are unlikely to occur, and there is no friction part, so there is no friction part. There is an advantage that loss due to cutting is less likely to occur. Also, from the viewpoint of handling properties of the coating liquid, the slide coating method can use a coating liquid that is less likely to change in concentration, viscosity, and composition of the coating liquid and that has high reactivity and changes over time. Further, since the coating liquid can be used up, waste is hardly generated, and since a high solid content coating liquid can be used, there is an advantage that the amount of solvent used can be reduced.

  In this step, as an embodiment in which a plurality of layers including a porous layer are simultaneously applied on the base sheet, at least the porous layer and another layer adjacent to the porous layer are simultaneously applied. If it is an aspect, it will not specifically limit. As such an embodiment, an embodiment (first embodiment) in which the porous layer and a receiving layer disposed on the porous layer and having dye-dyeing properties are simultaneously applied, and the porous layer are provided. And an embodiment (second embodiment) in which a layer other than the receiving layer is applied simultaneously.

  The first embodiment is not particularly limited as long as the porous layer and the receiving layer are simultaneously applied. As such an embodiment, for example, an embodiment in which the porous layer and the receptor layer disposed on the porous layer are simultaneously coated on the base sheet, and the base sheet on the base sheet An undercoat layer for improving the adhesion of the substrate, the porous layer disposed on the undercoat layer, and the receiving layer disposed on the porous layer, and a base sheet On the undercoat layer, a porous layer disposed on the undercoat layer, a primer layer disposed on the porous layer and provided to form the receiving layer, and on the primer layer The aspect which apply | coats the said receiving layer arrange | positioned simultaneously can be illustrated.

  On the other hand, as said 2nd embodiment, the undercoat layer which improves adhesiveness with the said base material sheet, and the porous layer arrange | positioned on the said undercoat layer are apply | coated simultaneously on the said base material sheet. A mode, an example in which the undercoat layer, a porous layer disposed on the undercoat layer, and a primer layer disposed on the porous layer and provided to form a receiving layer are simultaneously applied can do.

In this step, any of the first embodiment and the second embodiment can be suitably used. Among these, the first embodiment, that is, the porous layer and the porous layer can be used. Preferred is an embodiment in which a receiving layer disposed on top and having a dyeing property is applied simultaneously. When the thermal transfer image receiving sheet is provided with the receiving layer, the thermal transfer image receiving sheet can exhibit a function as a thermal transfer image receiving sheet. According to the first embodiment, a multilayer including the receiving layer can be applied simultaneously in one step. Therefore, the thermal transfer image receiving sheet can be produced with higher production efficiency. Moreover, in this process, it arrange | positions on the said undercoat layer on the base material sheet, the porous layer arrange | positioned on the said undercoat layer, and the said porous layer in the said 1st embodiment. It is preferable to use a mode in which the primer layer and the receiving layer disposed on the primer layer are applied simultaneously. This is because according to such an embodiment, a thermal transfer image-receiving sheet having excellent adhesion between layers and excellent printing sensitivity can be obtained.
Hereinafter, a receiving layer forming coating solution, an undercoat layer forming coating solution, and a primer layer used for forming the receiving layer, the undercoat layer, and the primer layer used in such an embodiment. The forming coating solution and the like will be described in order.

a) Receiving Layer Forming Coating Solution First, the receiving layer forming coating solution will be described. The receiving layer forming coating solution is not particularly limited as long as it can form a receiving layer excellent in dyeing property. In particular, in this step, it is preferable to use a resin in which the receptor layer-forming resin and the cooling gelling agent are dispersed and dissolved in an aqueous solvent as the receptor layer-forming coating solution. By using the receiving layer-forming coating liquid having such a composition, it is possible to effectively prevent the two coating liquids from being mixed when applied simultaneously with the porous layer-forming coating liquid. Because it can.

  The receiving layer forming resin is not particularly limited as long as it has dye-dyeing properties and can be dissolved and dispersed in an aqueous solvent. Examples of such a receiving layer forming resin include polyolefin resins, polyvinyl resins, polyester resins, polyurethane resins, polycarbonate resins, polyamide resins, poly (meth) acrylic acid resins, and cellulose derivative resins. Or a polyether-based resin. In this step, any of these receiving layer forming resins can be suitably used. Moreover, in this process, only 1 type may be used for the said resin for receptor layer formation, and 2 or more types from which a monomer composition, an average molecular weight, etc. differ may be used. Among these, it is preferable to use a polyvinyl resin in this step.

  Examples of the polyvinyl resin suitably used in this step include vinyl chloride / vinyl acetate copolymer, vinyl chloride / acrylic compound copolymer, ethylene / vinyl chloride / acrylic acid ester copolymer, and ethylene / vinyl acetate. / Vinyl chloride copolymer.

  The vinyl chloride / vinyl acetate copolymer is not particularly limited as long as it is a copolymer composed of vinyl chloride and vinyl acetate, and can be copolymerized with these essential monomers in addition to vinyl chloride and vinyl acetate. The polymer may be obtained by polymerizing a small amount, but is preferably a vinyl chloride / vinyl acetate binary copolymer.

The vinyl chloride / acrylic compound copolymer is not particularly limited as long as it is a copolymer composed of vinyl chloride and an acrylic compound, and a single amount copolymerizable with these essential monomers in addition to vinyl chloride and an acrylic compound. The polymer may be a copolymer of a small amount, but is preferably a vinyl chloride / acrylic compound binary copolymer.
In the present specification, “acrylic compound” means (meth) acrylic acid and / or an alkyl ester thereof.

  Examples of the acrylic compound include acrylic acid; acrylic acid salts such as calcium acrylate, zinc acrylate, magnesium acrylate, and aluminum acrylate; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-ethoxyethyl. Acrylic esters such as acrylate, 2-hydroxyethyl acrylate, n-stearyl acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane triacrylate; methacrylic acid; methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, tridecyl methacrylate, Cyclohexyl methacrylate, triethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, trimethylol trimethacrylate It can be mentioned methacrylic acid esters of bread, etc., and the like.

  The ethylene / vinyl chloride / acrylic acid ester copolymer and the ethylene / vinyl acetate / vinyl chloride copolymer (hereinafter, these copolymers are collectively referred to as “ethylene / vinyl chloride copolymer”). Is not particularly limited as long as it is a copolymer obtained by polymerizing at least three monomers of ethylene, vinyl chloride and acrylate, or three monomers of ethylene, vinyl acetate and vinyl chloride. In addition to the above three monomers, a small amount of monomer may be copolymerized, but ethylene / vinyl chloride / acrylic acid ester terpolymer or ethylene / vinyl acetate / vinyl chloride ternary. A copolymer is preferred.

  The ethylene / vinyl acetate / vinyl chloride copolymer may be a copolymer of ethylene / vinyl acetate copolymer (EVA) and vinyl chloride. As the EVA / vinyl chloride copolymer, EVA may be used. It may be a graft copolymerized vinyl chloride. EVA includes those in which all or part of vinyl acetate units in the copolymer is saponified.

  In this step, the “acrylic ester” constituting the ethylene / vinyl chloride / acrylic ester copolymer is a concept including a methacrylic ester in addition to the acrylic ester. Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-ethoxyethyl acrylate, 2-hydroxyethyl acrylate, n-stearyl acrylate, tetrahydrofurfuryl acrylate, and trimethylolpropane triacrylate. Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, t-butyl methacrylate, tridecyl methacrylate, cyclohexyl methacrylate, triethylene glycol dimethacrylate, dimethacrylic acid-1, Examples include 3-butylene and trimethylolpropane trimethacrylate.

  The resin for forming the receiving layer preferably has a glass transition temperature of 20 ° C. or higher, more preferably 30 ° C. or higher, and even more preferably 40 ° C. or higher. The receiving layer-forming resin preferably has a glass transition temperature of 100 ° C. or lower. In this step, when a receptor layer-forming resin having a glass transition temperature within the above range is included as the receptor layer, a thermal transfer image-receiving sheet particularly excellent in heat resistance can be obtained.

  The cooling gelling agent used in the receiving layer forming coating solution is not particularly limited as long as it can impart desired viscosity characteristics to the receiving layer forming coating solution. As such a cooling gelling agent, those similar to those used in the porous layer forming coating solution can be used.

  Moreover, the same thing as what is used for the said coating liquid for porous layer formation can be used also about the aqueous solvent used for the said coating liquid for receptor layer formation.

  The content of the cooling gelling agent contained in the receiving layer forming coating solution is not particularly limited as long as it is within a range in which desired viscosity characteristics can be imparted to the receiving layer forming coating solution. . Especially in this process, it is preferable that it is 50 mass% or less in conversion of solid content weight of the coating liquid for receiving layer formation, It is preferable to exist in the range of 5 mass%-35 mass% especially, Furthermore, 5 mass It is preferable that it is in the range of% -20 mass%. If the content of the cooling gelling agent is less than the above range, for example, when the porous layer and the receiving layer are applied on the base material sheet in this step, the two layers may be mixed. Because there is. Further, if the amount is larger than the above range, for example, when the receiving layer forming coating solution is applied onto the base material sheet in this step, streaks or unevenness may easily occur.

In addition to the receiving layer forming resin and the cooling gelling agent, examples of additives that can be added to the receiving layer forming coating solution include mold release agents, antioxidants, ultraviolet absorbers, and light stabilizers. , Fillers, pigments, antistatic agents, plasticizers, hot-melt materials, and surfactants.
Examples of the release agent include known ones such as silicone oil, phosphate ester compounds, and fluorine compounds, and silicone oil is particularly preferable.
Examples of the silicone oil include epoxy-modified silicone oil, alkyl-modified silicone oil, amino-modified silicone oil, fluorine-modified silicone oil, phenyl-modified silicone oil, epoxy / polyether-modified silicone oil, vinyl-modified silicone oil, hydrogen-modified silicone oil, etc. The modified silicone oil is preferred. The release agent is preferably added so as to be in the range of 0.5 to 30 parts by mass with respect to 100 parts by mass of the above-described receptor layer forming resin.
In addition, as the mold release agent, those obtained by emulsifying these silicone oils may be used.

  As solid content concentration of the coating liquid for receiving layer formation, it is preferable that it exists in the range of 10 mass%-50 mass%, for example in the range of 10 mass%-40 mass% especially. If the solid content concentration is too low, most of the solvent may be wasted, and if the solid content concentration is too high, the storage stability of the coating liquid may decrease and the viscosity may increase. .

  The viscosity of the receiving layer-forming coating solution is not particularly limited as long as it does not mix with other coating solutions that are simultaneously applied onto the substrate sheet in this step. In particular, in this step, it is preferably within a range of 1 mPa · s to 40 mPa · s at 40 ° C., particularly preferably within a range of 5 mPa · s to 30 mPa · s, and more preferably 7 mPa · s to 25 mPa · s. -It is preferable to be within the range of s.

b) Undercoat layer forming coating solution Next, the undercoat layer forming coating solution will be described. The undercoat layer forming coating solution used in this step is applied so as to be in contact with the base material sheet, and forms an undercoat layer provided to improve the adhesion between the base material sheet and other layers. It is used for this purpose. By providing the undercoat layer, the thermal transfer image-receiving sheet produced according to the present invention can be made excellent in the adhesion between the substrate sheet and the porous layer.

  The undercoat layer-forming coating solution used in this step is not particularly limited as long as it can form an undercoat layer that can improve the adhesion to the base sheet to a desired level. In particular, in this step, it is usually preferable to use a resin in which an undercoat layer forming resin and a cooling gelling agent are dispersed and dissolved in an aqueous solvent. By using an undercoat layer-forming coating solution having such a composition, it is possible to effectively prevent mixing with another coating solution applied simultaneously with the undercoat layer-forming coating solution. Because you can.

  The resin for forming the undercoat layer is not particularly limited as long as it can improve the adhesion between the base sheet and the porous layer and can be dissolved / dispersed in an aqueous solvent, Usually, an aqueous resin is used. As said aqueous resin, the thing similar to what is used for the said coating liquid for porous layer formation can be used.

  The cooling gelling agent used in the undercoat layer forming coating solution is not particularly limited as long as it can impart desired viscosity characteristics to the undercoat layer forming coating solution. As such a cooling gelling agent, those similar to those used in the porous layer forming coating solution can be used.

  Moreover, the same thing as what is used for the said coating liquid for porous layer formation can be used also about the aqueous solvent used for the said undercoat layer forming coating liquid.

  The ratio of the resin for forming the undercoat layer and the cooling gelling agent contained in the coating solution for forming the undercoat layer is within a range where desired viscosity characteristics can be imparted to the coating solution for forming the undercoat layer. If it is, it will not specifically limit. Especially in this process, it is preferable that a cooling gelling agent is 50 mass% or less in conversion of the solid content weight of the coating liquid for undercoat layer formation, and exists in the range of 5 mass%-35 mass% especially. It is preferable that it is in the range of 5% by mass to 20% by mass. When the content ratio of the cooling gelling agent is less than the above range, for example, when the undercoat layer forming coating solution is applied on the base sheet in this step, it is mixed with another coating solution. This is because there is a risk of it. Further, when the amount is larger than the above range, for example, when the undercoat layer forming coating solution is applied onto the base material sheet in this step, streaks or unevenness may easily occur.

  In addition to the undercoat layer-forming resin and the cooling gelling agent, examples of additives that can be added to the undercoat layer-forming coating solution include nonionic silicone surfactants, isocyanate compounds, and the like. Examples thereof include a curing agent such as a wetting material and a dispersing agent. The curing agent is particularly effective when, for example, a thermoplastic resin having active hydrogen is used as the undercoat layer forming resin.

  The undercoat layer forming coating solution may contain hollow particles. When hollow particles are included in the coating liquid for forming the undercoat layer, the solid content concentration is preferably in the range of 20% by mass to 90% by mass, and in particular, in the range of 40% by mass to 80% by mass. It is preferable to be within. In addition, about the hollow particle used for the said coating liquid for undercoat layer formation, since it is the same as that used for the coating liquid for porous layer formation mentioned above, description here is abbreviate | omitted.

  In this step, the solid content concentration of the coating liquid for forming the undercoat layer is, for example, preferably in the range of 1% by mass to 50% by mass, and more preferably in the range of 2% by mass to 10% by mass. If the solid content concentration is too low, most of the solvent may be wasted. If the solid content concentration is too high, the storage stability of the coating liquid may be reduced and the viscosity may be increased. .

  The viscosity of the coating liquid for forming the undercoat layer is not particularly limited as long as it does not mix with other coating liquids applied simultaneously on the base sheet in this step. In particular, in this step, it is preferably within a range of 1 mPa · s to 40 mPa · s at 40 ° C., particularly preferably within a range of 5 mPa · s to 30 mPa · s, and more preferably 7 mPa · s to 25 mPa · s. It is preferable to be within the range of s.

c) Primer layer forming coating solution Next, the primer layer forming coating solution will be described. The primer layer-forming coating solution is used for forming a primer layer provided for forming a receiving layer. By providing such a primer layer, there is an advantage that, for example, the smoothness of the receiving layer can be improved or the adhesion to the receiving layer can be improved.

  The primer layer forming coating solution used in this step is not particularly limited as long as it can form a primer layer having predetermined properties. In particular, in this step, it is preferable to use a resin in which the primer layer forming resin and the cooling gelling agent are dispersed and dissolved in an aqueous solvent. By using the primer layer forming coating solution having such a composition, it is possible to effectively prevent the primer layer forming coating solution from being mixed with another coating solution applied simultaneously with the primer layer forming coating solution. Because it can.

  The primer layer forming resin is not particularly limited as long as it can be dissolved / dispersed in an aqueous solvent, but an aqueous resin that is dissolved and dispersed in an aqueous solvent is usually used. As the water-based resin, the same resin as that used for the porous layer-forming coating solution can be used. In particular, as the primer layer-forming resin, an acrylic urethane resin or polyvinyl alcohol is used. Is preferred.

  About the additive which can be added to the primer layer forming coating solution, and the aqueous solvent used in the primer layer forming coating solution, the same ones as those used in the porous layer forming coating solution are used. Can be used.

  The cooling gelling agent used in the primer layer forming coating solution is not particularly limited as long as it can impart desired viscosity characteristics to the primer layer forming coating solution. As such a cooling gelling agent, those similar to those used in the porous layer forming coating solution can be used.

  The ratio of the primer layer forming resin contained in the primer layer forming coating solution and the cooling gelling agent is within a range where desired viscosity characteristics can be imparted to the primer layer forming coating solution. It is not particularly limited. Especially in this process, it is preferable that a cooling gelling agent is 50 mass% or less in conversion of the solid content weight of the primer layer formation coating liquid, and it exists in the range of 5 mass%-35 mass% especially. It is preferable that it is in the range of 5% by mass to 20% by mass. If the content ratio of the cooling gelling agent is less than the above range, for example, when the primer layer forming coating solution is applied on the base sheet in this step, it is mixed with other coating solutions. Because there is a fear. Further, when the amount is larger than the above range, for example, when the primer layer forming coating solution is applied onto the base material sheet in this step, streaks or unevenness may easily occur.

  In the present invention, the solid content concentration of the primer layer forming coating solution is, for example, preferably in the range of 10% by mass to 50% by mass, and more preferably in the range of 10% by mass to 25% by mass. If the solid content concentration is too low, most of the solvent may be wasted. If the solid content concentration is too high, the storage stability of the coating liquid may be reduced and the viscosity may be increased. .

d) Others In this step, the undercoat layer forming coating solution, the porous layer forming coating solution, the primer layer forming coating solution, and the receiving layer forming coating solution are formed on the substrate sheet. In the case of using a mode in which the coating liquids are simultaneously applied, the surface tension difference between the adjacent coating liquids is usually adjusted to be within a certain range so that these coating liquids are not mixed with each other at the time of coating.

2. Next, the cooling process used in the present invention will be described. This step is a step of forcibly cooling the multilayer coating film formed on the substrate sheet in the simultaneous multilayer coating step.

  Here, “forced cooling” in this step means that the multilayer coating film is cooled using a cooling means.

  The method for cooling the multilayer coating film in this step is not particularly limited as long as the multilayer coating film can be cooled to a desired temperature. As such a method, for example, a method of applying the multilayer coating film on a cooled substrate sheet, a surface of a roll that conveys the substrate sheet is cooled, and the multilayer coating is performed via the substrate sheet. Examples thereof include a method for cooling the film, a method for spraying cold air on the multilayer coating film, and a method for allowing the substrate sheet on which the multilayer coating film is formed to pass through a cooling zone adjusted to a room temperature below a desired temperature. . In particular, in this step, it is preferable to use a method of applying the multilayer coating film on a cooled substrate sheet. According to such a method, since the multilayer coating film can be forcibly cooled immediately after the multilayer coating film is applied on the substrate sheet, a plurality of layers constituting the multilayer coating film are mixed. This is because it can be prevented.

  In this step, the temperature at which the multilayer coating film is forcibly cooled is not particularly limited as long as the viscosity of each layer constituting the multilayer coating film can be improved to such an extent that the layers do not mix with each other. Absent. Further, the forced cooling temperature in this step depends on the kind of the cooling gelling agent described above. In particular, in this step, the cooling temperature is preferably in the range of 0 ° C to 30 ° C, particularly preferably in the range of 0 ° C to 25 ° C, and further in the range of 3 ° C to 20 ° C. Is preferred.

3. Other Steps The method for producing a thermal transfer image-receiving sheet of the present invention includes at least the simultaneous multilayer coating step and the cooling treatment step, but has other steps other than the above as necessary. Also good. As said other process used for this invention, the drying process which dries the solvent contained in the said multilayer coating film after the said cooling process process can be mentioned, for example. In the simultaneous multi-layer coating step, when an embodiment in which the receiving layer is not applied simultaneously is used, a receiving layer forming step of forming a receiving layer on the porous layer can be used after the cooling treatment step.

B. Next, the coating solution for forming a thermal transfer image receiving sheet of the present invention will be described. The coating solution for forming a thermal transfer image-receiving sheet of the present invention contains a cooling gelling agent and an aqueous solvent, has a viscosity in the range of 1 mPa · s to 300 mPa · s at 40 ° C., and is 0. It is in the range of 01 Pa · s to 15 Pa · s.

  According to the present invention, since it contains a cooling gelling agent and the viscosity is within the above range, it exhibits a relatively low viscosity at a high temperature and a relatively high viscosity at a low temperature. For example, by using in a method for producing a thermal transfer image receiving sheet having a simultaneous multilayer coating step and a cooling gelation step, such as the method for producing the thermal transfer image receiving sheet of the present invention, a plurality of layers are formed on the substrate sheet. They can be formed simultaneously without mixing with each other. For this reason, according to the coating liquid for forming a thermal transfer image receiving sheet of the present invention, a thermal transfer image receiving sheet can be formed with high efficiency.

The coating liquid for forming a thermal transfer image-receiving sheet of the present invention uses at least a cooling gelling agent and an aqueous solvent, and any other components may be used as necessary.
Hereafter, each structure used for this invention is demonstrated in order.

1. First, the cooling gelling agent used in the present invention will be described. The cooling gelling agent used in the present invention has a function of imparting the viscosity characteristics defined in the present invention to the thermal transfer image-receiving sheet forming coating liquid of the present invention.

  The cooling gelling agent used in the present invention is not particularly limited as long as it has a function of imparting the viscosity characteristic defined in the present invention to the thermal transfer image-receiving sheet forming coating liquid of the present invention. As such a cooling gelling agent, the same one as described in the above section “A. Method for producing thermal transfer image-receiving sheet” can be used. In particular, in the present invention, gelatin, polyvinyl alcohol, κ-carrageenan, or pectin is preferably used as the cooling gelling agent, and gelatin is particularly preferably used. This is because gelatin exhibits a cooling gelation characteristic by the mechanism as described above, and therefore it is not necessary to use another compound in combination in order to exhibit the cooling gelation characteristic. Moreover, since it is a material widely used industrially, it is advantageous in terms of availability and is easily applied to the present invention.

  In the present invention, only one type of cooling gelling agent may be used, or two or more types of cooling gelling agent may be used.

  As the amount of the cooling gelling agent contained in the thermal transfer image-receiving sheet forming coating liquid of the present invention, depending on the type of the cooling gelling agent, the thermal transfer image-receiving sheet forming coating liquid of the present invention has a predetermined viscosity characteristic. If it is in the range which can be provided, it will not specifically limit. Especially in this process, it is preferable that it is 50 mass% or less in conversion of solid content weight of the coating liquid for thermal transfer image-receiving sheet formation, It is preferable that it exists in the range of 5 mass%-35 mass% especially, Furthermore, It is preferable to be within the range of 5% by mass to 20% by mass.

2. Next, the aqueous solvent used in the present invention will be described. The aqueous solvent used in the present invention refers to a solvent containing water as a main component. The proportion of water in the aqueous solvent is usually 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. Examples of the solvent other than water used in this step include alcohols such as methanol, ethanol, isopropanol, and n-propanol; glycols such as ethylene glycol, diethylene glycol, and glycerin; esters such as ethyl acetate and propyl acetate; acetone, Ketones such as methyl ethyl ketone; Amides such as N, N-dimethylformamide can be used.

3. Thermal Transfer Image Receiving Sheet Forming Coating Liquid The thermal transfer image receiving sheet forming coating liquid of the present invention has a viscosity in the range of 1 mPa · s to 300 mPa · s at 40 ° C. and 0.01 Pa · s to 15 Pa at 20 ° C. -It is characterized by being within the range of s. The reason why the viscosity is defined within the above range in the present invention is based on the following reason. That is, when the viscosity at 40 ° C. is out of the above range, streaks or unevenness occurs when the thermal transfer image-receiving sheet forming coating liquid of the present invention is coated on the base sheet, and the coating quality is low. Although it will be damaged, it becomes possible to apply uniformly by being in the said range. Here, the viscosity at 40 ° C. is not particularly limited as long as it is within the above range, but in particular, it is preferably in the range of 1 mPa · s to 50 mPa · s, particularly 5 mPa · s to 40 mPa · s. It is preferable to be within the range.
Further, when the viscosity at 20 ° C. is outside the above range, for example, the thermal transfer image-receiving sheet forming of the present invention is used for the thermal transfer having the simultaneous multilayer coating step and the cooling process step as in the method for producing the thermal transfer image-receiving sheet of the present invention When used in the method for producing an image receiving sheet, the viscosity of the coating liquid becomes insufficient in the cooling process, and a plurality of coating liquids are mixed, but there is no such problem by being within the above range. Because. Here, the viscosity at 20 ° C. is not particularly limited as long as it is within the above range, but in particular, it is preferably in the range of 0.5 Pa · s to 15 Pa · s, particularly 1 Pa · s to 10 Pa. -It is preferable to be within the range of s.

  The viscosity can be measured, for example, using a tuning fork type vibration viscometer SV-10 manufactured by A & D.

  The coating liquid for forming a thermal transfer image-receiving sheet of the present invention is a coating liquid for forming an arbitrary functional layer constituting the thermal transfer image-receiving sheet by mixing other components other than the cooling gelling agent and the aqueous solvent. Can be used. For example, it can be used as a coating solution for forming a porous layer capable of forming a porous layer having heat insulation properties by using hollow particles as the other component. Here, the hollow particles used in the present invention, the addition amount thereof, and the like are the same as those described in the above-mentioned section “A. Method for producing thermal transfer image-receiving sheet”, and thus the description thereof is omitted here.

  In addition, the coating solution for forming a thermal transfer image-receiving sheet of the present invention is a coating for forming a receiving layer capable of forming a receiving layer having dye-dyeing properties by using a receiving layer-forming resin as the other component. It can be used as a working fluid. Here, the resin for forming the receiving layer used in the present invention, the amount of addition thereof, and the like are the same as those described in the above section “A. Method for producing thermal transfer image-receiving sheet”. Omitted.

  Further, the coating liquid for forming a thermal transfer image-receiving sheet of the present invention is a primer layer-forming coating provided for forming a receiving layer on a porous layer by using a primer layer-forming resin as the other component. It can be used as a liquid. Here, the primer layer forming resin used in the present invention and the amount of addition thereof are the same as those described in the above section “A. Method for producing thermal transfer image-receiving sheet”. Omitted.

  Furthermore, the coating liquid for forming a thermal transfer image-receiving sheet of the present invention uses an undercoat layer forming resin as the other component to form an undercoat layer that is provided to improve adhesion to the base sheet. It can be used as a coating liquid. Here, the resin for forming the undercoat layer used in the present invention and the addition amount thereof are the same as those described in the above section “A. Method for producing thermal transfer image-receiving sheet”. Is omitted.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

  Hereinafter, the present invention will be specifically described with reference to examples.

(Adjustment of coating liquid for forming porous layer)
Porous layer forming coating liquids 1 to 4 having the compositions shown in Table 1 below were prepared.

(Adjustment of coating solution for forming receiving layer)
The receiving layer forming coating solutions 1 to 4 shown in Table 2 below were prepared.

  The viscosities of the coating liquid for forming a porous layer and the coating liquid for forming a receiving layer were measured using a tuning fork type vibration viscometer SV-10 manufactured by A & D. The results are shown in Table 3.

1. Example 1
Resin-coated paper is prepared as a base sheet, and a slide coating machine is used so that the porous layer forming coating liquid 1 and the receiving layer forming coating liquid 1 are laminated in this order on the base sheet. Simultaneous multilayer coating was applied. Thereafter, the film was forcibly cooled for 60 seconds in a cooling zone adjusted to 7.2 ° C., and further dried at 50 ° C. for 5 minutes to prepare a thermal transfer image-receiving sheet.
During simultaneous multi-layer coating, mixing and repelling between the coating liquids did not occur, and a thermal transfer image-receiving sheet having a uniform film thickness of each layer was obtained.

2. Example 2
A simultaneous multilayer coating was applied in the same manner as in Example 1 except that the porous layer forming coating solution 3 was used instead of the porous layer forming coating solution 1. During simultaneous multi-layer coating, mixing and repelling between the coating liquids did not occur, and a thermal transfer image-receiving sheet having a uniform film thickness of each layer was obtained.

3. Example 3
A simultaneous multilayer coating was applied in the same manner as in Example 1 except that the porous layer forming coating solution 2 was used instead of the porous layer forming coating solution 1. During simultaneous multi-layer coating, mixing and repelling between the coating liquids did not occur, and a thermal transfer image-receiving sheet having a uniform film thickness of each layer was obtained.

4). Example 4
A simultaneous multilayer coating was applied in the same manner as in Example 3 except that the receiving layer forming coating solution 2 was used instead of the receiving layer forming coating solution 1. During simultaneous multi-layer coating, mixing and repelling between the coating liquids did not occur, and a thermal transfer image-receiving sheet having a uniform film thickness of each layer was obtained.

5. Example 5
A simultaneous multilayer coating was applied in the same manner as in Example 3 except that the receiving layer forming coating solution 3 was used instead of the receiving layer forming coating solution 1. During simultaneous multi-layer coating, mixing and repelling between the coating liquids did not occur, and a thermal transfer image-receiving sheet having a uniform film thickness of each layer was obtained.

6). Comparative Example A thermal transfer image receiving sheet was prepared in the same manner as in Example 1 except that the receiving layer forming coating solution 4 and the porous layer forming coating solution 4 were used. As a result, the layers were mixed and a thermal transfer image receiving sheet could not be obtained.

(Evaluation of prints)
The printing characteristics of the thermal transfer image receiving sheets prepared in Examples 1 to 5 were evaluated by the following methods.

(1) Preparation of printed matter Prepare the thermal transfer image-receiving sheet obtained in the example, and use the thermal transfer sheet (Canon, for Cp720) to print the gradation pattern in the order of yellow, magenta, and cyan, and then protect them. The layer was transferred to obtain a print. Next, another thermal transfer image receiving sheet was prepared, and yellow, magenta, and cyan colors were transferred in this order to form a black image, and the protective layer was transferred to obtain a printed matter. The printing conditions are shown below.

(Printing conditions)
Heating element average resistance value: 5285 (Ω)
Main scanning direction printing density; 300 dpi
Sub-scanning direction print density; 300 dpi
Applied voltage: 22 (V)
1 line cycle; 2 (msec./line)
Printing start temperature: 27 (° C)
Applied pulse (gradation control method): Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 in one line period and having a pulse length obtained by equally dividing one line period into 256 The duty ratio of the divided pulses was fixed at 90%, and the number of pulses per line period was divided from 0 to 255 into 18 steps. Thereby, different energy can be given to 18 steps.

(2) Evaluation of dye-dyeing property Bk color density was measured about the said printed matter. For the measurement, a spectrophotometer (Spectrolino, manufactured by Gretag Macbeth) was used. The results are shown in Table 3.

It is process drawing which shows an example of the manufacturing method of the thermal transfer image receiving sheet of this invention. It is explanatory drawing explaining a slide coat method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,15 ... Base material sheet 2 ... Multilayer coating film 10 ... Thermal transfer image receiving sheet 11, 12, 13 ... Coating liquid 14 ... Back roll 21 ... Porous layer 22 ... Receiving layer

Claims (4)

Using a water-based porous layer forming coating solution containing hollow particles and a cooling gelling agent, and simultaneously applying a plurality of layers including a porous layer on a substrate sheet;
In the simultaneous multilayer coating step, forcibly cooling a coating film composed of a plurality of layers formed on a base sheet, a cooling treatment step, and a method for producing a thermal transfer image receiving sheet,
The viscosity of the coating liquid for forming a porous layer is within a range of 5 mPa · s to 300 mPa · s at 40 ° C. and within a range of 0.5 Pa · s to 15 Pa · s at 20 ° C. A method for producing a thermal transfer image-receiving sheet.   The simultaneous multilayer coating step uses an aqueous receptive layer forming coating solution containing a receptive layer forming resin and a cooling gelling agent, on the base sheet, on the porous layer and on the porous layer The method for producing a thermal transfer image receiving sheet according to claim 1, wherein the receiving layer to be disposed is applied simultaneously.   The thermal transfer image-receiving sheet according to claim 1 or 2, wherein the cooling gelling agent is gelatin.   A cooling gelling agent and an aqueous solvent are contained, and the viscosity is in the range of 1 mPa · s to 300 mPa · s at 40 ° C. and in the range of 0.01 Pa · s to 15 Pa · s at 20 ° C. A coating solution for forming a thermal transfer image-receiving sheet.

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