JP2007260969A - Thermal transfer image receiving sheet and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mainly provide a thermal transfer image receiving sheet, which is excellent in print sensitivity and can be manufactured inexpensively. <P>SOLUTION: This thermal tranfer image receiving sheet includes a heat insulating base material sheet and an accepting layer formed on the base material sheet, wherein the accepting layer comprises a laminate of a resin thin film layer made of a resin material having a thin film workability and an image forming layer which is made of a dyeable resin and formed on the resin thin film layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thermal transfer image receiving sheet used in an image forming method using a thermal transfer system, and more particularly to a thermal transfer image receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost.

  Conventionally, an image forming method using a thermal transfer method is known as one of color or monochrome image forming techniques, and has been widely used as a means for easily obtaining a high-quality image. The thermal transfer system is a method for forming an image by transferring a thermal transfer sheet having a dye exhibiting specific thermal properties from a thermal transfer sheet to a thermal transfer image receiving sheet using a thermal printing device such as a thermal head or a laser. is there. Such a thermal transfer system has the advantage that the apparatus can be miniaturized and is low in cost.

The thermal transfer system is roughly classified into two types, a thermal melting transfer system and a thermal diffusion transfer system, depending on a dye transfer mechanism from the thermal transfer sheet to the thermal transfer image receiving sheet. The thermal melt transfer system is a system in which an image is formed by using a thermal transfer sheet having a hot melt dye and transferring the hot melt dye to a thermal transfer image receiving sheet by a heat transfer process. On the other hand, the thermal diffusion transfer system is a system in which an image is formed by using a thermal transfer sheet having a thermal diffusible dye and transferring the thermal diffusible dye to a thermal transfer image receiving sheet by a thermal diffusion transfer mechanism.
In the thermal diffusion transfer method, by controlling the degree of heating of the thermal transfer sheet, the transfer amount of the thermal diffusible dye to the thermal transfer image-receiving sheet can be arbitrarily adjusted. An image can be formed, which is advantageous for full-color image formation. Because of these advantages, the thermal diffusion transfer thermal transfer technology is widely used in business photographs, personal computer printers, video printers, and the like.

  By the way, the thermal transfer image-receiving sheet used in the thermal transfer system has a structure in which a receiving layer containing a resin having a dyeing property to a dye is generally formed on a base sheet having heat resistance, Conventionally, a receiving layer containing a resin having this dyeing property has been formed by a gravure coating method. However, this gravure coating method requires a large amount of solvent, and also requires a drying step after coating, and thus has a disadvantage of being inferior in cost and high-speed productivity. For this reason, formation of the said receiving layer was calculated | required by the melt extrusion method which can be processed without a solvent.

A polyester resin is generally known as a resin having dyeability applicable to such a melt extrusion method. For example, Patent Document 1 discloses a thermal transfer image-receiving sheet using such a polyester resin and having a receiving layer formed by a melt extrusion method.
However, although the above polyester resin has the advantage of better dyeing properties than other resins, it is difficult to make a thin film by itself, so the receiving layer using the polyester resin is formed thin. There was a drawback that it was difficult to do. For this reason, the thermal transfer image-receiving sheet having a receiving layer using a polyester-based resin has a thick receiving layer, and the distance from the surface of the base sheet to the surface of the receiving layer becomes long. There is a problem in that the heat insulating property of the base sheet cannot be effectively functioned and the printing sensitivity is lowered. Further, there is a problem that a thick receiving layer is disadvantageous in manufacturing cost.

JP-A-8-324139

  The present invention has been made in view of the above problems, and has as its main object to provide a thermal transfer image-receiving sheet that is excellent in printing sensitivity and can be produced at low cost.

  In order to solve the above-mentioned problems, the present invention is a thermal transfer image-receiving sheet comprising a base sheet having heat insulation properties and a receiving layer formed on the base sheet, wherein the receiving layer has a thin film processability. There is provided a thermal transfer image-receiving sheet comprising a resin thin film layer containing a resin material and an image forming layer formed on the resin thin film layer and containing a dyeable resin.

According to the present invention, the receiving layer has a configuration in which the resin thin film layer and the image forming layer are laminated, and the resin material contained in the resin thin film layer has thin film processability. By having it, it becomes possible to form a receiving layer having a small thickness regardless of the type of dyeing resin used in the image forming layer. Therefore, according to the present invention, a thermal transfer image-receiving sheet having a short distance from the surface of the base sheet on the side where the receiving layer is formed to the surface of the image forming layer on the side far from the base sheet is obtained. Can do.
For this reason, according to the present invention, it is possible to obtain a thermal transfer image receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost.

  In the present invention, the distance from the surface of the base sheet on which the receiving layer is formed to the surface of the image forming layer on the side far from the base sheet is preferably 8 μm or less. As a result, when forming an image using the thermal transfer image-receiving sheet of the present invention, it becomes possible to effectively use the heat insulation provided in the base material sheet and effectively use heat during image formation. This is because the printing sensitivity of the thermal transfer image receiving sheet of the invention can be substantially improved.

  In the present invention, the resin material is preferably an ethylene / (meth) acrylic acid copolymer (EMAA) resin or a polyester resin having a molecular weight distribution of 1.44 or less. Since such ethylene / (meth) acrylic acid copolymer (EMAA) resin and polyester resin are more excellent in thin film processability, such ethylene / (meth) acrylic acid copolymer (EMAA) resin, Alternatively, by using a polyester resin, the receiving layer in the present invention can be made thinner.

  Furthermore, in the present invention, the dyeable resin is preferably an amorphous polyester resin. This is because the amorphous polyester resin is excellent in dyeing property, and by using such a polyester resin, the thermal transfer image-receiving sheet of the present invention can be made more excellent in printing sensitivity.

  In order to solve the above problems, the present invention provides a resin thin film layer forming composition containing a resin material having thin film processability on a base sheet having heat insulation properties, and an image formation containing a dyeable resin. It has a receiving layer forming step of forming a receiving layer having a configuration in which the resin thin film layer and the image forming layer are laminated on the base sheet by coextrusion of the layer forming composition. A method for producing a thermal transfer image receiving sheet is provided.

According to the present invention, the receiving layer forming step is a process of coextruding the resin thin film layer forming composition and the image forming layer forming composition, and the resin thin film layer forming composition. Since the resin material contained has thin film processability, it is possible to form a thin receiving layer regardless of the type of dyeing resin contained in the composition for forming an image forming layer. It becomes possible. Therefore, according to the present invention, a thermal transfer image receiving sheet having a short distance from the surface of the base sheet on which the receiving layer is formed to the surface of the image forming layer on the side far from the base sheet is manufactured. be able to.
For this reason, according to the present invention, it is possible to manufacture a thermal transfer image receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost.

  In the present invention, the receiving layer forming step has a distance of 8 μm or less from the surface of the base sheet on the side where the receiving layer is formed to the surface of the image forming layer far from the base sheet. It is preferable to form the receiving layer as described above. As a result, when forming an image using the thermal transfer image-receiving sheet produced according to the present invention, it is possible to effectively use the heat insulation during the image formation by effectively functioning the heat insulating property of the base sheet. Therefore, the printing sensitivity of the thermal transfer image receiving sheet produced according to the present invention can be substantially improved.

  Moreover, in this invention, after the said receiving layer formation process, the back surface base material and the back surface layer formed on the said back surface base material on the surface on the opposite side to the surface in which the receiving layer of the said base material sheet was formed. It is preferable to have a back surface layer forming step of extruding and laminating the back surface laminate having the base material sheet and the back surface base material with the adhesive layer interposed therebetween. By having such a back surface layer forming step, it becomes possible to form a heat transfer image receiving sheet on which a back surface layer having a desired function is formed without using a solvent. Therefore, the manufacture of the heat transfer image receiving sheet of the present invention This is because the steps for carrying out the method can be simplified.

  INDUSTRIAL APPLICABILITY The present invention has an effect that a thermal transfer image receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost can be manufactured.

  Hereinafter, the thermal transfer image receiving sheet of the present invention and the method for producing the thermal transfer image receiving sheet will be described.

A. First, the thermal transfer image receiving sheet of the present invention will be described. The thermal transfer image-receiving sheet of the present invention has a heat-insulating base sheet and a receiving layer formed on the base sheet, and the receiving layer includes a resin material having thin film processability. It has a configuration in which a resin thin film layer and an image forming layer containing a dyeable resin are laminated on the resin thin film layer.

  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 the thermal transfer image receiving sheet of the present invention. As illustrated in FIG. 1, the thermal transfer image receiving sheet 10 of the present invention has a configuration in which a receiving layer 2 is laminated on a base sheet 1, and the receiving layer 2 is formed on the base sheet 1. The resin thin film layer 2a is made of a resin material and the image forming layer 2b is formed on the resin thin film layer 2a and contains a dyeable resin.

Conventionally, the dyeing resin used for the receiving layer of the thermal transfer image-receiving sheet is inferior in thin film processability alone, so that the thickness of the receiving layer is increased, and this causes the printing sensitivity of the thermal transfer image-receiving sheet. There was a problem that would be damaged. Further, since the receiving layer is thickened, there is also a problem that it is disadvantageous in terms of manufacturing cost of the thermal transfer image receiving sheet.
In this regard, according to the present invention, the receiving layer has a configuration in which the resin thin film layer and the image forming layer are laminated, and the resin material contained in the resin thin film layer is a thin film. By having processability, it is possible to form a receiving layer having a small thickness regardless of the type of dyeing resin used for the image forming layer. Thereby, in the present invention, the distance from the surface of the base sheet on the side where the receptor layer is formed to the surface of the image forming layer on the side far from the base sheet (hereinafter simply referred to as “lamination distance”). May be shortened).
For this reason, according to the present invention, it is possible to obtain a thermal transfer image-receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost.

  The thermal transfer image receiving sheet of the present invention has the above base sheet and the above receiving layer, and has other layers as required. Hereinafter, each configuration of the thermal transfer image receiving sheet of the present invention will be described in detail.

1. Receiving layer First, the receiving layer in the present invention will be described. The receiving layer used in the present invention has a structure in which a resin thin film layer containing a resin material and an image forming layer containing a dyeable resin are formed on the resin thin film layer. In the present invention, since the receiving layer has a structure in which such a resin thin film layer and an image forming layer are laminated, the receiving layer can be made thin, whereby the lamination layer is formed. The distance can be shortened.
Hereinafter, such a receiving layer will be described.

(1) Image forming layer First, the image forming layer will be described. The image forming layer used in the present invention contains a dyeable resin and has a function of receiving a dye when an image is formed using the thermal transfer image receiving sheet of the present invention.

  As the dyeing resin used for the image forming layer in the present invention, when forming an image using the thermal transfer image receiving sheet of the present invention, the dyeing property capable of receiving the dye used in the thermal transfer sheet. If it is resin provided with this, it will not specifically limit, According to the use of the thermal transfer image receiving sheet of this invention, a manufacturing method, etc., it can select and use arbitrarily.

  Examples of such dyeing resins include polyolefin resins such as polypropylene, halogenated polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, and polyvinylidene chloride, polyvinyl acetate, and ethylene-vinyl acetate. Polymers, vinyl polymers such as polyacrylic esters, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polystyrene resins, polyamide resins, copolymers of olefins such as ethylene and propylene, and other vinyl monomers, ionomers And cellulose resins such as cellulose diacetate, polycarbonate resins, phenoxy resins, epoxy resins, polyvinyl acetal resins, and polyvinyl alcohol resins. Furthermore, known as tackifying resins and resin modifiers, for example, hydrogenated petroleum resins, aliphatic hydrocarbon resins, alicyclic hydrocarbon resins, aromatic hydrocarbon resins, rosin resins Examples thereof include resins, terpene resins, and coumarone indene resins. In particular, in the present invention, it is preferable to use a polyester resin as the dyeing resin, and it is most preferable to use an amorphous polyester resin among the polyester resins. This is because the amorphous polyester resin is excellent in dyeing property, and by using such an amorphous polyester resin, the thermal transfer image-receiving sheet of the present invention can be made more excellent in printing sensitivity.

  The amorphous polyester resin used in the present invention is not particularly limited as long as it is substantially amorphous. In particular, in the present invention, Tg is preferably in the range of 20 ° C. to 180 ° C., particularly preferably in the range of 40 ° C. to 150 ° C., and more preferably in the range of 50 ° C. to 100 ° C. Those are preferred. This is because if the Tg is lower than the above range, the storage stability of the thermal transfer image-receiving sheet of the present invention may be lowered. Moreover, it is because it may become difficult to form a homogeneous image forming layer by a melt extrusion method when it is higher than the above range.

The amorphous polyester resin used in the present invention preferably has a melt viscosity at 220 ° C. in the range of 200 to 8000 Pa · sec. When the melt viscosity at 220 ° C. is within the above range, the thermal transfer image-receiving sheet of the present invention can be excellent in dye transfer sensitivity and transfer efficiency during thermal transfer even under high-speed printing conditions, and also during extrusion processing. This is because an appropriate resin pressure can be obtained, which makes it easy to process.
In addition, the said melt viscosity makes the value measured on condition of the following as the value of the melt viscosity in this invention. At this time, the measurement viscosity is measured after the measurement sample is dried to a moisture content of 200 ppm or less.
・ Equipment: SMIMADZU FLOWTESTER CFT-500C manufactured by Shimadzu Corporation
・ Measurement conditions: Constant temperature method is used (load condition: 50 kg, die size: die hole diameter 1.00 mm, die length 10 mm)

Further, the amorphous polyester resin used in the present invention preferably has a number average molecular weight (Mn) of 15000 or more, particularly preferably in the range of 20000 to 40000. If the number average molecular weight is lower than the above range, the elastic modulus and heat resistance of the image forming layer are lowered, and it may be difficult to secure the releasability between the thermal transfer sheet and the thermal transfer image receiving sheet of the present invention. is there. Moreover, it is because adhesiveness with the base material sheet mentioned later may deteriorate when a number average molecular weight is larger than the said range.
In addition, the value obtained by measuring by GPC on the following conditions shall be used for the number average molecular weight in this invention.
Equipment used: Water permeation gel permeation chromatography (GPC)
Column: Connect Shodex KF802, 804L, 806L Standard substance: Polystyrene Solvent: Tetrahydrofuran

  As such an amorphous polyester resin, a polyester resin containing terephthalic acid, isophthalic acid and ethylene glycol as main components, and containing other acid components and / or other glycol components as copolymerization components is preferably used. it can.

  Examples of the other acid component include aliphatic dibasic acids (for example, adipic acid, sebacic acid, azelaic acid) and aromatic dibasic acids (for example, isophthalic acid, diphenyldicarboxylic acid, 5-tert-butyl). Isophthalic acid, 2,2,6,6-tetramethylbiphenyl-4,4-dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,1,3-trimethyl-3-phenylindene-4,5-dicarboxylic acid) Etc.

  Examples of the glycol component include aliphatic diols (for example, neopentyl glycol, diethylene glycol, propylene glycol, butanediol, hexanediol), alicyclic diols (for example, 1,4-cyclohexanedimethanol) or aromatic diols ( For example, xylylene glycol, bis (4-β-hydroxyphenyl) sulfone, 2,2- (4-hydroxyphenyl) propane derivative), and the like can be given.

  As the dyeable resin used in the present invention, a resin obtained by adding a polymer (resin) having an epoxy group or a carbodiimide group to the amorphous polyester resin can also be used. Such a dyeable resin can improve the extrusion processability at a high temperature range and the heat resistance of the receiving layer because the polymer containing the epoxy group or carbodiimide group undergoes a crosslinking reaction with the polyester resin. Has the advantage that the releasability of the high printing energy portion during printing can be improved.

  Examples of the polymer having an epoxy group include esters of methacrylic acid or acrylic acid and various glycidyl alcohols, such as methyl glycidyl ester, butyl glycidyl ester, polyethylene glycol diglycidyl ester, polypropylene glycol diglycidyl ester, Neopentyl glycol diglycidyl steal and the like can be mentioned.

  Moreover, as a polymer which has the said carbodiimide group, the Nisshinbo Co., Ltd. carbodilite (HMV-8CA) etc. can be used, for example.

  In the present invention, one kind of resin may be used as the dyeing resin, or two or more kinds of resins may be mixed and used.

  The image forming layer in the invention may contain other compounds in addition to the dyeing resin. Such other compounds can be arbitrarily selected and used depending on the function imparted to the thermal transfer image-receiving sheet of the present invention. Hereinafter, other compounds used in the receptor layer of the present invention will be described.

(Wax)
The image forming layer in the present invention may contain a wax for the purpose of improving thermal sensitivity, thermal transferability and abrasion resistance. Examples of such waxes include waxy fatty acid amides, various lubricants, synthetic waxes such as paraffin wax, natural waxes such as candelilla wax and carnauba wax, and oils such as silicone oil and half-loroalkyl ether. It can be improved by the addition of a kind. In addition to polyethylene resins and phosphate esters, other resins such as silicone resins, tetrafluoroethylene resins and fluoroalkyl ether resins, and inorganic lubricants such as silicon carbide and silica can also be used.

(Release agent)
The image forming layer in the invention preferably contains a release agent. This is because inclusion of the release agent can effectively prevent the thermal transfer sheet and the receiving layer from being fused at the time of printing. As such a release agent, for example, silicone oil, phosphate ester compounds, fluorine compounds, and other release agents known in the art can be used. Of these, silicone oil is preferably used in the present invention.

  As the silicone oil used in the present invention, epoxy-modified, alkyl-modified, amino-modified, fluorine-modified, phenyl-modified, epoxy-polyether-modified silicone, vinyl-modified silicone oil or OH-modified silicone having active hydrogen is suitable. Can be used. Of these, low molecular weight modified silicone is preferably used in the present invention.

  Specific examples of the low molecular weight modified silicone used in the present invention include a modified silicone in which a polyether group and an amino group are bonded, and a polyether modified silicone because it is difficult to lower the printing sensitivity and surface property of the image forming layer. And epoxy-modified silicone. In the present invention, polyether-modified silicone is particularly preferably used among the above-described modified silicone oils. The polyether group of the polyether-modified silicone is partially decomposed by heat (180 ° C. or more) at the time of extrusion, but the remaining polyether group can maintain a balance of compatibility with the above-described dyeable resin. Thus, bleeding out during extrusion film formation and dye transfer is moderately suppressed. For this reason, silicone can be present in a well-balanced manner on the surface of the receiving layer, so that good releasability can be imparted to the image forming layer.

  The content of the release agent is not particularly limited as long as it is within a range in which a desired release property can be imparted to the receiving layer according to the use of the thermal transfer image receiving sheet of the present invention. Especially in this invention, it is preferable to exist in the range of 0.5 weight part-10 weight part with respect to 100 weight part of said dyeable resin, and it exists in the range of especially 1 weight part-5 weight part. Is preferred. This is because if the content of the release agent is less than the above range, a desired releasability may not be obtained in the image forming layer in the present invention. Also, if the content is larger than the above range, for example, when a protective layer is formed on the image forming layer, the adhesion between the protective layer and the image forming layer may be impaired. .

(UV absorber and light stabilizer)
The image forming layer in the invention may contain a UV agent and a light stabilizer. The UV absorber and the light stabilizer that can be used in the present invention are not particularly limited as long as they have a function of improving the light resistance of a thermal transfer print formed using the thermal transfer image-receiving sheet of the present invention. Examples of such UV absorbers and light stabilizers include JP-A Nos. 59-158287, 63-74666, 63-145089, 59-196292, 62-229594, and 63-. Examples of the compounds described in JP-A Nos. 122596, 61-283595, and JP-A-1-204788, and compounds that improve image durability in photographs and other image recording materials may be mentioned.

(Filler)
A filler may be used for the image forming layer in the invention. The filler used in the present invention has a function of improving the slidability of the thermal transfer sheet by being contained in the image forming layer and can impart desired high-speed printing characteristics to the thermal transfer image-receiving sheet of the present invention. There is no particular limitation. In the present invention, general inorganic fine particles and organic resin particles can be used as the filler.

  Examples of the inorganic fine particles include silica gel, calcium carbonate, titanium oxide, acidic clay, activated clay, and alumina. Examples of the organic fine particles include resin particles such as fluororesin particles, guanamine resin particles, acrylic resin particles, and silicon resin particles. The content of these fillers can be arbitrarily determined according to the specific gravity of the filler.

(Pigment)
The image forming layer in the invention may contain a pigment. The pigment that can be used in the present invention is not particularly limited as long as it has a function of improving the image quality formed by the thermal transfer image-receiving sheet of the present invention by being contained in the image forming layer. Examples of such pigments include titanium white, calcium carbonate, zinc oxide, barium sulfate, silica, talc, clay, kaolin, activated clay, and acid clay. The addition amount of the pigment can be arbitrarily determined and used as long as the object of the present invention is not impaired.

(Plasticizer)
The image forming layer in the present invention may contain a plasticizer. The plasticizer that can be used in the present invention is not particularly limited as long as it has a function of plasticizing the image forming layer by being contained in the image forming layer and improving the diffusibility of the dye in the image forming layer. Examples of such plasticizers include phthalates, trimellitic esters, adipic esters, other saturated or unsaturated carboxylic esters, citrate esters, epoxidized soybean oil, and epoxidized linseed oil. And epoxy stearic acid epoxies, orthophosphoric acid esters, phosphorous acid esters, glycol esters and the like. The content of these plasticizers can be arbitrarily determined in accordance with the type of plasticizer and the like as long as the object of the present invention is not impaired.

  The thickness of the image forming layer in the present invention is not particularly limited as long as the lamination distance can be within a desired range according to the thickness of a resinous thin film layer to be described later. In particular, in the present invention, it is preferably in the range of 0.5 μm to 6 μm, particularly preferably in the range of 0.5 μm to 4 μm, and more preferably in the range of 0.5 μm to 1.5 μm. It is preferable. If the thickness is larger than the above range, it may be difficult to make the lamination distance within a desired range depending on the type of resin material contained in the resinous thin film layer described later, and it is thinner than the above range. This is because it may be difficult to form an image forming layer having a uniform thickness.

(2) Resin-made thin film layer Next, the resin-made thin film layer in this invention is demonstrated. The resin thin film layer used in the present invention is made of a resin material having thin film processability.

  As the resin material constituting the resin thin film layer, when the receiving layer in the present invention is formed by co-extrusion of the resin thin film layer and the image forming layer, the thickness of the receiving layer is desired to be the stacking distance. If it has thin film workability of the grade which can be set in this range, it will not specifically limit. In particular, the resin material used in the present invention has a thickness of 1.5 μm to 8 μm when the receptor layer in the present invention is formed by co-extrusion of the resin thin film layer and the image forming layer. It is preferable that the film has a thin film workability enough to be within a range of 1.5 μm to 4.5 μm, more preferably within a range of 1.5 μm to 2.5 μm. It is because it becomes easy to form a resin-made thin film layer with a thin thickness by melt-extrusion because the resin material has the above-described degree of thin film processability. Here, the thin film processability is as follows. A single piece of the corresponding resin material is used with an extrusion film forming machine having the following specifications, the line speed is fixed at 50 m / min, the extrusion amount (number of rotations) is lowered, and the film thickness is gradually increased. It means a value obtained by forming a film while making it thin, and evaluating a minimum film thickness at which the film can be stably formed without causing film breakage or ear warp. In addition, the value of thin film processability shall be the value which can be thinned most at resin temperature 200-300 degreeC.

<Extruder film forming machine specifications>
Screw diameter: 50mm
Screw type: Screw with mixing L / D: 28
Extrusion amount: Max 50kg / Hr LDPE (MFR = 7)
Number of revolutions: 5 to 280 RPM
T die: 11S type straight manifold hole T die effective opening length: 430mm
T die lip gap: 0.8mm
Air gap: 100mm

Specific examples of the resin material used in the present invention are not particularly limited as long as they have the above-described thin film processability, and may be appropriately selected and used depending on the use of the thermal transfer image receiving sheet of the present invention. it can. Among them, in the present invention, ethylene / (meth) acrylic acid copolymer (EMAA) resin, polyethylene resin, and polyester resin having a molecular weight distribution of 1.44 or less can be preferably used. This is because both the ethylene / (meth) acrylic acid copolymer (EMAA) resin and the polyethylene resin have high melt tension. In particular, ethylene (meth) acrylic acid copolymer (EMAA) resin has a carboxylic acid group in the molecule, and thus has a high melt tension due to a weak cross-linking action between molecular chains. It is preferably used because it has the advantages of excellent processability and excellent adhesion to the substrate.
Moreover, it is because the polyester-type resin whose molecular weight distribution is 1.44 or less is excellent in thin film processability, since the viscosity at the time of heat melting is uniform.

  As an example of the said polyester-type resin, a polycarbonate resin etc. can be mentioned, for example.

  In the present invention, as the resin material used for the resin thin film layer, only one type of resin material may be used, or two or more types of resin materials may be mixed and used.

  The resin thin film layer in the present invention may contain other compounds in addition to the resin material. Such other compounds are not particularly limited as long as they do not impair the thin film processability of the resin material, and arbitrary compounds are used depending on the function to be imparted to the thermal transfer image-receiving sheet of the present invention. be able to. Examples of such other compounds include antistatic agents and fluorescent brighteners, white imparting agents such as calcium carbonate and titanium oxide.

  The thickness of the resinous thin film layer in the present invention is not particularly limited as long as the lamination distance can be within a desired range according to the thickness of the image forming layer described above. In particular, in the present invention, it is preferably in the range of 1 μm to 7.5 μm, particularly preferably in the range of 1 μm to 4 μm, and more preferably in the range of 1 μm to 2.5 μm. If the thickness is larger than the above range, it may be difficult to make the lamination distance within a desired range. If the thickness is smaller than the above range, it is difficult to form a resin thin film layer having a uniform thickness. This is because there is a possibility of becoming.

2. Next, the base sheet used in the present invention will be described. The substrate sheet used in the present invention has a heat insulating property, supports the receiving layer formed on the substrate sheet, and has a function of imparting the self-supporting property of the thermal transfer image receiving sheet of the present invention. is there.

  The substrate sheet used in the present invention is not particularly limited as long as it has a desired heat insulation property depending on the printing temperature or the like when forming an image using the thermal transfer image-receiving sheet of the present invention. . In the present invention, a resin film substrate made of a plastic resin and a paper substrate made of a paper material are usually used as such a substrate sheet.

  The resin film substrate is not particularly limited as long as it is made of a plastic resin having desired heat resistance. Examples of such plastic resins include polyester, polyacrylate, polycarbonate, polyurethane, polyimide, polyetherimide, cellulose derivative, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polystyrene, acrylic, polyvinyl chloride, and polychlorinated. Vinylidene, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone, polysulfone, polyether sulfone, tetrafluoroethylene, perfluoroalkyl vinyl ether, polyvinyl fluoride, tetrafluoroethylene-ethylene, tetrafluoroethylene-hexafluoropropylene, poly Examples include chlorotrifluoroethylene and polyvinylidene fluoride. Among these, in the present invention, polyethylene terephthalate and polypropylene resin can be preferably used.

  The resin film substrate used in the present invention is preferably a resin void film containing bubbles among the plastic resins. This is because the resin-made void film containing bubbles is excellent in heat resistance and can easily change the heat resistance of the resin film substrate arbitrarily by changing the bubble content.

Such a resinous void film is not particularly limited as long as it has a bubble content sufficient to express desired heat insulation properties, depending on the type of plastic resin constituting the film. Among these, the resin void film used in the present invention preferably has a bubble content of 15% to 65%, particularly preferably 30% to 50%. This is because if the ratio is smaller than the above range, the ratio of the porosity, which is microvoids of fine voids, is small, and there is a possibility that characteristics as a heat insulating layer such as satisfactory heat insulating properties and cushioning properties cannot be exhibited. On the other hand, if it is larger than the above range, the film becomes thin, the strength of the resin film substrate is inferior, and the image formed using the thermal transfer image-receiving sheet of the present invention may be uneven.
Here, the bubble content (V) is calculated by dividing the density (ρ) of the target resinous void film by the density (ρ ₀ ) of the entire solid content of the resinous void film from the void percentage. It is calculated by rate (V) = (1−ρ / ρ ₀ ) × 100 (%).
In addition, the density ((rho)) of resin-made void films is a density of the heat insulation layer which has a foaming structure, and is a numerical value in the structure containing the space | gap.

  The resin film substrate used in the present invention may contain other compounds in addition to the plastic resin. Examples of such other compounds include white pigments and fillers. By using such a white pigment or filler as the other compound, the resin film substrate can be made into a white opaque film.

  The thickness of the resin film substrate used in the present invention is not particularly limited as long as it is within a range in which a desired heat insulating property can be expressed, depending on the type of the plastic resin, etc., but usually within a range of 20 μm to 100 μm. More preferably, it is in the range of 5 μm to 60 μm, more preferably in the range of 30 μm to 50 μm.

  The paper substrate is not particularly limited as long as it has a desired heat insulating property. Examples of such paper base materials include condenser paper, glassine paper, sulfuric acid paper, high-size paper, synthetic paper (polyolefin-based, polystyrene-based), high-quality paper, art paper, coated paper, and cast coat. Examples include paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, and the like.

  Moreover, as said paper-made base material, what has thickness in the range of 80 micrometers-200 micrometers normally, More preferably in the range of 100 micrometers-180 micrometers, More preferably, it exists in the range of 120 micrometers-160 micrometers.

  The substrate sheet used in the present invention may be composed of a single layer or may have a configuration in which a plurality of layers are laminated. In addition, a configuration in which a plurality of layers are stacked may be a configuration in which layers having the same composition are stacked, or a configuration in which layers having different compositions are stacked. Especially, it is preferable that the base material sheet used for this invention has the structure by which the several layer was laminated | stacked, and it is still more preferable that it has a structure by which the layer of a different composition was laminated | stacked. This is because, when the base sheet used in the present invention has such a configuration, it becomes easy to impart a desired function to the base sheet.

As a configuration in which layers having different compositions are laminated, a configuration in which arbitrary layers are combined can be used according to the function to be imparted to the thermal transfer image receiving sheet of the present invention. Examples of such a configuration include a mode of laminating paper base materials having different compositions represented by an example of laminating cellulose fiber paper and synthetic paper, and a resin film base material on at least one side of the paper base material. The aspect which laminates | stacks can be mentioned. Especially in this invention, it is preferable to use the structure by which the said resin-made film base materials and the said paper-made base materials were laminated | stacked.
As a lamination method, for example, dry lamination, wet lamination, extrusion, or the like can be used.

3. Thermal transfer image-receiving sheet In the thermal transfer image-receiving sheet of the present invention, the receiving layer has a configuration in which the image-forming layer is laminated on the resin thin film layer, whereby the thickness of the receiving layer can be reduced. Therefore, it has an advantage that the stacking distance can be shortened. The stacking distance in the present invention is particularly limited as long as it is within a range in which a desired image sensitivity can be imparted to the thermal transfer image-receiving sheet of the present invention, depending on the type of dyeing resin contained in the image forming layer. It is not a thing. Especially in this invention, it is preferable that the said lamination | stacking distance is 8 micrometers or less, It is especially preferable that it exists in the range of 1.5 micrometers-4.5 micrometers, More preferably, it exists in the range of 1.5 micrometers-2.5 micrometers. When the stacking distance is within the above range, it is possible to effectively function the heat resistance of the base sheet when an image is formed using the thermal transfer image receiving sheet of the present invention. This is because the thermal transfer image receiving sheet of the invention can be made more excellent in printing sensitivity.

Here, the stacking distance will be described with reference to the drawings. FIG. 2 is a schematic diagram for explaining the stacking distance. As illustrated in FIG. 2, the lamination distance in the thermal transfer image receiving sheet 10 of the present invention is from the surface of the base sheet 1 on the side where the receiving layer 2 is formed, from the base sheet 1 of the image forming layer 2b. The distance to the surface on the far side (the distance represented by A in FIG. 2A) is indicated.
In addition, for example, as illustrated in FIG. 2B, in the case where the thermal transfer image receiving sheet 10 ′ of the present invention has an intermediate layer 7 formed between the base sheet 1 and the receiving layer 2. Also, the stacking distance refers to the distance (the distance represented by A in FIG. 2B) to the surface of the image forming layer 2b far from the base sheet 1.

  In the thermal transfer image receiving sheet of the present invention, an intermediate layer having an arbitrary function may be formed between the base sheet and the receiving layer as long as the stacking distance can be within a desired range. Examples of such an intermediate layer include an adhesive layer that improves the adhesion between the receptor layer and the substrate sheet, a white color imparting layer that colors the thermal transfer image-receiving sheet of the present invention white, and the thermal transfer image-receiving sheet of the present invention. Examples thereof include a concealing layer for improving the appearance or antistatic for preventing charging of the thermal transfer image receiving sheet of the present invention.

  The adhesive layer is not particularly limited as long as it is made of an adhesive material that can bond the base sheet and the receiving layer with a desired adhesive force. Examples of such adhesive materials include urethane resins and polyester resins. Further, when a thermoplastic resin having active hydrogen and a curing agent such as an isocyanate compound are used in combination, good adhesiveness can be obtained.

  The white color imparting layer is not particularly limited as long as it contains a white agent capable of making the thermal transfer image receiving sheet of the present invention have a desired white color. In particular, in the present invention, a fluorescent whitening agent can be suitably used as the whitening agent. Examples of such optical brighteners include stilbene, distilbene, benzoxazole, styryl-oxazole, pyrene-oxazole, coumarin, aminocoumarin, imidazole, benzimidazole, pyrazoline, distyryl. -Biphenyl fluorescent whitening agent and the like can be mentioned.

  In addition, the concealment layer is not particularly limited as long as it can conceal the glaring feeling and unevenness of the base sheet. Especially in this invention, the layer containing a titanium oxide can be used suitably from a viewpoint of the freedom degree of selection of a base material sheet. There are two types of titanium oxide, rutile type titanium oxide and anatase type titanium oxide. Among them, it is preferable to use anatase type titanium oxide in the present invention.

  In the thermal transfer image receiving sheet of the present invention, a back surface layer having an arbitrary function may be formed on the surface opposite to the surface on which the receiving layer of the base material sheet is formed, if necessary. As such a back layer, a layer having a desired function can be used according to the use of the thermal transfer image-receiving sheet of the present invention. In particular, in the present invention, it is preferable to use a back layer having a function of improving the transferability of the thermal transfer image-receiving sheet and a function of preventing curling as the back layer.

  The material constituting the back layer exhibiting the above-described transportability improving function and anti-curl function is not particularly limited as long as it is a material capable of imparting desired transportability and anti-curl property, but usually an acrylic resin, a cellulose resin, A binder resin made of a polycarbonate resin, a polyvinyl acetal resin, a polyvinyl alcohol resin, a polyamide resin, a polystyrene resin, a polyester resin, a halogenated polymer, or the like is used in which a filler is added as an additive.

  The filler is not particularly limited as long as a desired slip property can be imparted to the back layer. As such a filler, for example, an organic filler such as an acrylic filler, a polyamide filler, a fluorine filler, or a polyethylene wax, or an inorganic filler such as silicon dioxide or a metal oxide can be used. Among them, it is preferable to use a polyamide-based filler in the present invention. This is because the polyamide filler has a high melting point and is thermally stable, has good oil resistance and chemical resistance, and is difficult to be dyed with a dye.

  As such a polyamide filler, a spherical filler is usually used. The average particle diameter may be arbitrarily adjusted according to the amount of filler added, etc., which will be described later. In the present invention, the average particle diameter is preferably in the range of 0.01 μm to 30 μm. It is preferably within a range of 01 μm to 10 μm. This is because if the average particle size is smaller than the above range, the filler is hidden in the back surface layer, and it may be difficult to exhibit a sufficient slip function. Further, if the average particle size is larger than the above range, the protrusion from the back surface layer becomes large, and as a result, the friction coefficient may be increased or the filler may be lost.

  Moreover, as said polyamide-type filler, the mixture of the 2 or more types of polyamide-type fillers from which average particle diameter differs can also be used.

  As a constituent material of the polyamide filler, a nylon resin is preferably used. Examples of such a nylon resin include nylon 6, nylon 66, nylon 12, and the like. In the present invention, nylon 12 is preferably used. This is because nylon 12 filler is excellent in water resistance and has a relatively small change in properties due to water absorption.

  The content of the filler in the back surface layer may be determined by appropriately adjusting the content within a range in which a desired transportability can be obtained according to the constituent material of the filler to be used, the average particle size, and the like. Is preferably in the range of 0.01% by mass to 200% by mass, particularly preferably in the range of 0.01% by mass to 100% by mass, and in particular, 0.05% by mass to 2% by mass. % Is preferable. This is because if the content is less than the above range, the slipperiness becomes insufficient, and there is a possibility of causing trouble such as paper jam at the time of feeding the printer. Further, if the amount is larger than the above range, it may be slippery and color misalignment or the like is likely to occur in the printed image.

4). Method for Producing Thermal Transfer Image Receiving Sheet The method for producing the thermal transfer image receiving sheet of the present invention is not particularly limited as long as it is a method capable of producing a thermal transfer image receiving sheet having the above-described configuration. As such a method, for example, a method described in the section of “B. Manufacturing method of thermal transfer image receiving sheet” described later can be given.

B. Method for Producing Thermal Transfer Image Receiving Sheet Next, the method for producing the 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 comprises: a resin thin film layer forming composition containing a resin material having thin film processability on a base sheet having heat insulation; and an image formation containing a dyeable resin. It has a receiving layer forming step of forming a receiving layer having a configuration in which the resin thin film layer and the image forming layer are laminated on the base sheet by coextrusion of the layer forming composition. It is what.

  A method for producing such a thermal transfer image receiving sheet of the present invention will be described with reference to the drawings. FIG. 3 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. 3, the method for producing a thermal transfer image-receiving sheet of the present invention comprises a resin thin film layer forming composition 2a ′ containing a resin material having thin film processability on a base sheet 1 having heat insulation properties, The composition 2b ′ for forming an image forming layer containing a dyeable resin is co-extruded to form a structure in which the resin thin film layer 2a and the image forming layer 2b are laminated on the base sheet 1. It has the receiving layer formation process which forms the receiving layer 2 which has it, It is characterized by the above-mentioned.

  According to the present invention, the receiving layer forming step is for coextruding the resin thin film layer forming composition and the image forming layer forming composition, and the resin thin film layer forming composition. The thin resin layer can be formed regardless of the type of dyeing resin contained in the image forming layer forming composition, because the resin material contained in the film has thin film processability. Is possible. Therefore, according to the present invention, a thermal transfer image-receiving sheet having a short distance from the surface of the base sheet on which the receiving layer is formed to the surface of the image forming layer on the side far from the base sheet is manufactured. can do.

Conventionally, the dyeing resin that has been used for the receiving layer of the thermal transfer image-receiving sheet has the disadvantage that it is inferior in thin film workability alone, so that the thickness of the receiving layer to be formed is increased, As a result, there is a problem that the printing sensitivity of the thermal transfer image receiving sheet is lowered.
In addition, since the receiving layer becomes thicker, there is a problem that it is disadvantageous in terms of manufacturing cost.
In this regard, according to the present invention, a resin that has been difficult to process into a thin film by itself is used as the dyeable resin by coextruding the dyeable resin with a resin material having thin film processability. Even in this case, a thin receiving layer can be formed.
Therefore, according to the present invention, it is possible to manufacture a thermal transfer image receiving sheet that is excellent in printing sensitivity and can be manufactured at low cost.

  The method for producing a thermal transfer image receiving sheet of the present invention includes the above-described receiving layer forming step, and may include other steps as necessary. Hereafter, each process which comprises the manufacturing method of such a thermal transfer image receiving sheet of this invention is demonstrated in detail.

1. Receiving layer forming step First, the receiving layer forming step used in the present invention will be described. In this step, a resin-made thin film layer forming composition containing a resin material having thin film processability and an image forming layer forming composition containing a dyeable resin are combined on a base sheet having heat insulation properties. It is a step of forming a receiving layer having a configuration in which the resin thin film layer and the image forming layer are laminated on the base sheet by extrusion. In the method for producing a thermal transfer image receiving sheet of the present invention, since this step is to form a receiving layer by such a method, it is possible to form a receiving layer having a small thickness. A thermal transfer image receiving sheet having a short distance from the surface on the side on which the receiving layer is formed to the surface on the side farther from the base sheet of the image forming layer (hereinafter sometimes referred to simply as “stacking distance”). It can be manufactured.
Hereinafter, such a receiving layer forming step will be described.

  A method of coextruding a composition for forming a resinous thin film layer containing a resin material having thin film processability and a composition for forming an image forming layer containing a dyeable resin on the substrate sheet in this step The method is not particularly limited as long as it can form a receiving layer in which both layers are laminated with a uniform thickness, and generally known co-extrusion methods can be used.

  In this step, the extrusion temperature at the time of co-extrusion of the receiving layer is not particularly limited as long as the resin thin film layer forming composition and the image forming layer forming composition can be made to have a desired viscosity. . Especially in this invention, it is preferable to exist in the range of 150 to 350 degreeC, and it is especially preferable to exist in the range of 200 to 300 degreeC.

  Further, the receiving layer formed by this step has a distance of 8 μm or less from the surface of the base sheet on the side where the receiving layer is formed to the surface of the image forming layer far from the base sheet. It is preferable that it is within a range of 1.5 μm to 4.5 μm, particularly preferably within a range of 1.5 μm to 2.5 μm. In this step, the base material sheet is provided when an image is formed using the thermal transfer image receiving sheet produced by the present invention by laminating the receiving layer so that the laminating distance is in such a range. This is because the heat transfer function can be made to function effectively and the heat at the time of image formation can be used effectively, so that the thermal transfer image-receiving sheet produced according to the present invention can be made more excellent in printing sensitivity.

  The resin thin film layer forming composition used in this step contains a resin material having thin film processability, and may contain other compounds as necessary. Such a resin material and other compounds are the same as those described in the above section “A. Thermal transfer image receiving sheet”, and thus description thereof is omitted here.

  Moreover, the said composition for image forming layer formation used for this process contains dyeable resin, and another compound may be contained as needed. Such a dyeable resin and other compounds are the same as those described in the above section “A. Thermal transfer image-receiving sheet”, and thus description thereof is omitted here.

  Furthermore, since the base material sheet used in this step is the same as that described in the section “A. Thermal transfer image receiving sheet”, description thereof is omitted here.

2. Other Steps In the method for producing a thermal transfer image receiving sheet of the present invention, other steps other than the above receiving layer forming step may be used as necessary. Such other steps are not particularly limited as long as a desired function can be imparted to the thermal transfer image-receiving sheet produced according to the present invention, depending on the application of the thermal transfer image-receiving sheet produced according to the present invention. Absent. Especially in this invention, it has the back surface layer formation process which forms a back surface layer on the surface opposite to the surface in which the receiving layer of the base material sheet was formed after the said receiving layer formation process as said other process. Is preferred.

  As the back surface layer forming step used in the present invention, the back surface having a desired function on the surface opposite to the surface on which the receiving layer is formed of the base sheet on which the receiving layer is laminated by the receiving layer forming step. There is no particular limitation as long as the layer can be formed. Among them, in the present invention, on the surface opposite to the surface on which the receiving layer of the base material sheet is formed, a back surface laminate having a back surface base material and a back surface layer formed on the back surface base material, It is preferable to use a back surface layer forming step of forming a back surface layer by extrusion lamination so that the base material sheet and the back surface base material face each other through an adhesive layer. By using such a back surface layer forming step, it becomes possible to form a heat transfer image receiving sheet on which a back surface layer having a desired function is formed without using a solvent. It is because the process of implementing this manufacturing method can be simplified.

  Such a back surface layer forming step will be described with reference to the drawings. FIG. 4 is a schematic view showing an example of a back surface layer forming step preferably used in the method for producing a thermal transfer image receiving sheet of the present invention. As illustrated in FIG. 4, the back surface layer forming step used in the present invention includes a back surface base material 3 on the surface opposite to the surface on which the receiving layer 2 of the base sheet 1 is formed by the receiving layer forming step. A back laminate 5 having a back layer 4 formed on the back substrate 3 is extrusion laminated so that the substrate sheet 1 and the back substrate 3 face each other through an adhesive layer 6. Preferably there is.

  In the case where the back surface layer forming step used in the present invention is to form the back surface layer by such a method, the adhesive layer can be bonded to the back surface laminate and the base sheet with a desired adhesive force. As long as it contains a functional resin, it is not particularly limited. Examples of such adhesive resins include urethane resins, α-olefin-maleic anhydride resin and other polyolefin resins, polyester resins, acrylic resins, epoxy resins, urea resins, melamine resins, and phenols. Resin, vinyl acetate resin, cyanoacrylate resin and the like.

  The back laminate is not particularly limited as long as a back layer having a desired function is laminated on the back substrate. Such a back layer is the same as that described in the section “A. Thermal transfer image-receiving sheet”, and therefore the description thereof is omitted here.

  Moreover, as a back surface base material used for the said back surface laminated body, if it has the self-supporting property of the grade which can support the said back surface layer, it will not specifically limit. Such a back surface base material is the same as that described in the above section “A. Thermal transfer image receiving sheet 2. Base material sheet”, and thus description thereof is omitted here.

  Furthermore, as a method of extrusion laminating the back surface laminate so that the base material sheet and the back surface base material face each other through an adhesive layer, the back surface laminate and the base material sheet are bonded with a desired adhesive force. The method is not particularly limited as long as it can be adhered, and generally known methods can be used.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

  Next, the present invention will be described more specifically by giving examples and comparative examples. In the following examples and comparative examples, “part” or “%” is based on mass unless otherwise specified.

(1) Example 1
A composition for forming an image forming layer having the following composition was melted on a void-containing film (G1211 38 μm manufactured by Toyobo Co., Ltd.) having a thickness of 4 μm and a resin thin film layer forming composition having the following composition: A receiving layer was formed by coextrusion.

<Image forming layer forming composition (Example 1)>
・ Polyester resin (Byron 290, manufactured by Toyobo Co., Ltd.) 100 parts ・ Silicone oil (X-22-3939A, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part

<Resin thin film layer forming composition (Example 1)>
100 parts of EMAA resin (Nucleel AN4228C, manufactured by Mitsui DuPont Polychemical Co., Ltd .: thin film workability = 4 μm or less)

  Thereafter, the following non-laminate surface of the core paper obtained by extruding and laminating the following composition for forming the back layer on the surface opposite to the surface on which the receiving layer of the void-containing film is formed is extruded using the following adhesive layer material. Lamination was performed to obtain a thermal transfer image receiving sheet 1.

<Composition for forming back layer (Example 1)>
・ 100 parts of polybutylene terephthalate resin (600 KP, manufactured by Polyplastics Co., Ltd.)

<Adhesive layer material (Example 1)>
EMAA resin (Nucrel N09008C, manufactured by Mitsui DuPont Polychemical Co., Ltd.)
100 copies

(2) Example 2
A thermal transfer image-receiving sheet 2 was obtained in the same manner as in Example 1 except that the resin thin film layer forming composition having the following composition was used.

<Resin thin film layer forming composition (Example 2)>
・ Polyethylene resin (Mirason 10P, manufactured by Mitsui Chemicals, Inc .: thin film processability = 6 μm)
100 copies

(3) Example 3
A thermal transfer image-receiving sheet 3 was obtained in the same manner as in Example 1 except that the resin thin film layer forming composition having the following composition was used.

<Resin thin film layer forming composition (Example 3)>
Polycarbonate resin (OQ1020C, manufactured by Nippon GE Plastics Co., Ltd .: thin film processability = 6 μm: molecular weight distribution (Mw / Mn) = 1.41) 100 parts

(4) Example 4
A thermal transfer image-receiving sheet 4 was obtained in the same manner as in Example 1 except that the composition having the following composition was used as the image-forming layer-forming composition.

<Image forming layer forming composition (Example 4)>
・ Polyester resin (Byron 290, manufactured by Toyobo Co., Ltd.) 70 parts ・ Polycarbonate resin (OQ1020C, manufactured by GE Plastics Co., Ltd.) 30 parts ・ Silicone oil (X-22-3939A, Shin-Etsu Chemical Co., Ltd.) 1 part)

(5) Example 5
A thermal transfer image-receiving sheet 5 was obtained in the same manner as in Example 1 except that the composition having the following composition was used as the image-forming layer-forming composition.

<Image forming layer forming composition (Example 5)>
・ Polyester resin (Byron 290, manufactured by Toyobo Industries Co., Ltd.) 30 parts ・ Polycarbonate resin (OQ1020C, manufactured by GE Plastics Co., Ltd.) 70 parts ・ Silicone oil (X-22-3939A, Shin-Etsu Chemical Co., Ltd.) 1 part)

(6) Example 6
A thermal transfer image receiving sheet 6 was obtained in the same manner as in Example 1 except that the same image forming composition and resin thin film layer forming composition as in Example 1 were extruded onto a void-containing film with a thickness of 8 μm.

(7) Example 7
A thermal transfer image-receiving sheet 7 was obtained in the same manner as in Example 1 except that the composition having the following composition was used as the image-forming layer-forming composition.

<Image forming layer forming composition (Example 7)>
-Polyvinyl butyral resin (BM-1, manufactured by Sekisui Chemical Co., Ltd.) 100 parts-Silicone oil (X-22-3939A, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part

(8) Comparative Example 1
An attempt was made to extrude only a composition for forming an image forming layer having the following composition into a void-containing film with a thickness of 8 μm or less without forming a resin thin film layer. A thermal transfer image-receiving sheet 8 was obtained in the same manner as in Example 1 except that it was laminated.

<Image forming layer forming composition (Comparative Example 1)>
Polyester resin (Byron 290, manufactured by Toyobo Co., Ltd .: thin film processability = 15 μm)
100 parts ・ Silicone oil (X-22-3939A, manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part

(9) Comparative Example 2
A thermal transfer image-receiving sheet 9 was obtained in the same manner as in Example 1 except that no image forming layer was formed and only a resin thin film layer forming composition having the following composition was extruded into a void-containing film with a thickness of 6 μm.

<Resin thin film layer forming composition (Comparative Example 2)>
-EMAA resin (Nucrel AN4228C, manufactured by Mitsui DuPont Polychemical Co., Ltd .: thin film workability = 4 μm or less) 100 parts

(10) Comparative Example 3
The thermal transfer image-receiving sheet 10 was obtained in the same manner as in Example 1 except that the image forming composition similar to Example 1 and the resin thin film layer forming composition having the following composition were extruded into a void-containing film with a thickness of 9 μm. It was.

<Resin thin film layer forming composition (Comparative Example 3)>
100 parts of polypropylene resin (F-329RA, Prime Polymer Co., Ltd .: thin film processability = 9 μm)

(11) Comparative Example 4
An attempt was made to extrude an image-forming composition similar to Example 1 and a resin thin-film layer-forming composition having the following composition into a void-containing film with a thickness of 8 μm or less. A thermal transfer image receiving sheet 11 was obtained in the same manner as in Example 1 except that it was extruded onto a void-containing film.

<Resin thin film layer forming composition (Comparative Example 4)>
Polycarbonate resin (lexan 141, manufactured by GE Plastics Co., Ltd .: molecular weight distribution Mw / Mn = 1.49: thin film processability = 15 μm) 100 parts

(Evaluation)
Next, the thermal transfer image receiving sheets of the above examples and comparative examples were evaluated as follows.

<Evaluation method>
(Thermal transfer recording) As a thermal transfer film, a transfer film UPC-740 for a sublimation transfer printer UP-D70A manufactured by Sony Corporation was used, and the thermal transfer image-receiving sheets of the above-mentioned examples and comparative examples were used. Were placed facing each other, and Y, M, C, and a protective layer were used in the order of thermal transfer recording from the back surface of the thermal transfer film using a thermal head under the following conditions.

(Print printing A)
A gradation image was formed by thermal transfer recording under the following conditions.
-Thermal head: KYT-86-12MFW11 (manufactured by Kyocera Corporation)
-Heating element average resistance: 4412 (Ω)
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
Applied power: 0.136 (w / dot)
・ One line cycle: 6 (msec.)
-Printing start temperature: 30 (° C)
-Print size: 100mm x 150mm
・ Gradation printing: Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 with a pulse length that equally divides one line period into 256 in one line period, the duty of each divided pulse The ratio is fixed at 40%, and the number of pulses per line cycle is increased in increments of 17 from 0 in 1 step, 17 in 3 steps, 34 in 3 steps, and 0 to 255, depending on the gradation. Thus, 16 gradations from 1 step to 16 steps were controlled.
・ Transfer of protective layer: Using a multi-pulse test printer that can vary the number of divided pulses from 0 to 255 within a line period and having a pulse length obtained by equally dividing the line period into 256 lines. The duty ratio was fixed to 50%, the number of pulses per line period was fixed to 210, solid printing was performed, and the protective layer was transferred to the entire print surface.

(Print density)
The maximum reflection density of the printed matter was measured with a visual filter using an optical reflection densitometer (Macbeth RD-918, manufactured by Macbeth). The evaluation criteria were as follows.
○ ・ ・ ・ ・ Maximum reflection density 2.0 or more × ・ ・ ・ ・ Maximum reflection density 2.0 or less

(Thin film processability)
It was visually judged whether or not a film could be formed at 8 μm by extruding the receiving layer of each of the above Examples and Comparative Examples into a void-containing film. The evaluation criteria at this time were as follows.
○ ··· Can be formed at 8 µm or less × · · · Can not be formed at 8 µm or less Here, the thin film workability is fixed at 50 m / min using an extrusion film forming machine of the following specifications. Then, the extrusion amount (number of rotations) was lowered, the film was formed while the film thickness was gradually reduced, and the minimum film thickness that can be stably formed without film breakage or ear warp was evaluated. In addition, the value of thin film processability shall be the value which can be thinned most at resin temperature 200-300 degreeC.

<Extruder film forming machine specifications>
Screw diameter: 50mm
Screw type: Screw with mixing L / D: 28
Extrusion amount: Max 50kg / Hr LDPE (MFR = 7)
Number of revolutions: 5 to 280 RPM
T die: 11S type straight manifold hole T die effective opening length: 430mm
T die lip gap: 0.8mm
Air gap: 100mm

  The evaluation results are as shown in Table 1 below.

It is a schematic sectional drawing which shows an example of the thermal transfer image receiving sheet of this invention. It is the schematic explaining the lamination | stacking distance in the thermal transfer image receiving sheet of this invention. It is the schematic which shows an example of the manufacturing method of the thermal transfer image receiving sheet of this invention. It is the schematic which shows an example of the back surface layer formation process used for the manufacturing method of the thermal transfer image receiving sheet of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base material sheet 2 ... Receiving layer 2a ... Resin thin film layer 2b ... Image forming layer 3 ... Back surface base material 4 ... Back surface layer 5 ... Back surface laminated body 6 ... Adhesive layer 7 ... Intermediate | middle layer 10, 10 '... Thermal transfer image receiving sheet

Claims (8)

A thermal transfer image receiving sheet having a base sheet having heat insulation and a receiving layer formed on the base sheet,
The receiving layer has a configuration in which a resin thin film layer containing a resin material having thin film processability and an image forming layer containing a dyeable resin formed on the resin thin film layer are laminated. A thermal transfer image receiving sheet.   The distance from the surface of the base sheet on the side where the receiving layer is formed to the surface of the image forming layer on the side far from the base sheet is 8 μm or less. Thermal transfer image receiving sheet.   The thermal transfer image-receiving sheet according to claim 1, wherein the resin material is an ethylene / (meth) acrylic acid copolymer (EMAA) resin.   The thermal transfer image receiving sheet according to claim 1 or 2, wherein the resin material is a polyester resin having a molecular weight distribution of 1.44 or less.   The thermal transfer image-receiving sheet according to any one of claims 1 to 4, wherein the dyeable resin is an amorphous polyester resin.   By co-extruding a resin thin film layer forming composition containing a resin material having thin film processability and an image forming layer forming composition containing a dyeable resin on a base sheet having heat insulation properties, A method for producing a thermal transfer image receiving sheet, comprising: a receiving layer forming step of forming a receiving layer having a configuration in which the resin thin film layer and the image forming layer are laminated on the base sheet.   In the receiving layer forming step, the distance from the surface of the base sheet on which the receiving layer is formed to the surface of the resin thin film layer on the side far from the base sheet is 8 μm or less. The method for producing a thermal transfer image receiving sheet according to claim 6, wherein the receiving layer is formed. After the receptive layer forming step, a back surface laminate having a back surface base material and a back surface layer formed on the back surface base material on the surface opposite to the surface on which the receptive layer of the base material sheet is formed, The production of a thermal transfer image receiving sheet according to claim 6 or 7, further comprising a back layer forming step of extrusion laminating so that the base sheet and the back substrate are opposed to each other through an adhesive layer. Method.

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