JP2019209510A - Thermal transfer image-receiving sheet - Google Patents

Abstract

To provide a thermal transfer image-receiving sheet that is excellent in the prevention of print unevenness, print wrinkles, folding wrinkles and adhesive material attachment.SOLUTION: A thermal transfer image-receiving sheet 10 has a receiving layer 11, a heat insulation layer 12 containing a binder material and hollow particles, a base material 13, an adhesive layer 14, and a peeling base material 15. The base material 13 has a density of 0.70 g/cmor more and 1.60 g/cmor less, and a Martens hardness measured from the receiving layer 11 side is 5 N/mmor more and 25 N/mmor less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a thermal transfer image receiving sheet.

  Conventionally, various printing methods are known. Among them, the sublimation thermal transfer method can freely adjust density gradation, has excellent reproducibility of intermediate colors and gradations, and has a high quality comparable to silver salt photography. Image formation is possible.

  In this sublimation type thermal transfer system, a thermal transfer sheet provided with a dye layer containing a sublimable dye and a thermal transfer image receiving sheet provided with a receiving layer are superimposed, and then the thermal transfer sheet is heated by a thermal head provided in the thermal transfer printer. The sublimation dye in the dye layer is transferred to the receiving layer provided in the thermal transfer image receiving sheet, image formation is performed, and a printed matter is obtained. Usually, such a thermal transfer image receiving sheet is required to have a printing unevenness preventing property capable of preventing the occurrence of density unevenness in an image formed on a receiving layer.

  By the way, in recent years, for the purpose of improving the productivity of printed matter and improving the image density, high-speed and high-heat image formation has been carried out. However, conventional seal-type thermal transfer image-receiving sheets, for example, receiving layers and substrates When a high-speed and high-heat image formation is performed on a thermal transfer image-receiving sheet provided with an adhesive layer and a release substrate, there is a problem that wrinkles (so-called printing wrinkles) are generated in the formed image.

  In order to solve the problem of printing wrinkles, a thermal transfer image-receiving sheet using a porous resin film is known as a base material. In the thermal transfer image-receiving sheet having such a configuration, a base for peeling the release base material is known. Bending to the material side caused wrinkles (hereinafter referred to as “folded wrinkles”) on the surface of the printed material, which significantly deteriorated the appearance of the printed material.

Furthermore, in order to solve the problem of wrinkles, Patent Document 1 proposes a thermal transfer image receiving sheet comprising a receiving layer, a heat insulating layer, a porous substrate, an adhesive layer, and a release substrate in this order. ing.
However, when the thermal transfer image-receiving sheet proposed in Patent Document 1 is cut into a desired size by a cutting mechanism after image formation in a thermal transfer printer, adhesion of the adhesive material to the cutting mechanism (cutter, etc.) is large. In the end, cutting cannot be performed, the cut surface is distorted, the adhesive material adheres to the printed material, and the printed material is not discharged properly.

JP 2013-28066 A

The present inventors have now found that the above problem can be solved by setting the density of the substrate and the Martens hardness of the thermal transfer image-receiving sheet within a specific numerical range.
The present invention has been made in view of the above problems, and the problem to be solved is to provide a thermal transfer image receiving sheet having high printing unevenness prevention, printing wrinkle prevention, folding wrinkle prevention and adhesive material adhesion prevention. It is to be.

The thermal transfer image-receiving sheet of the present invention comprises a receptor layer, a heat insulating layer containing a binder material and hollow particles, a substrate, an adhesive layer, and a release substrate, and the density of the substrate is 0.70 g / cm ^3. above 1.60 g / cm ³ or less, the Martens hardness measured from the receiving layer side, characterized in that at 5N / mm ² or more 25 N / mm ² or less.

  In one embodiment, the porosity of the heat insulation layer is not less than 45% and not more than 85%.

  In one embodiment, the thickness of the heat insulation layer is 10 μm or more and 20 μm or less.

  In one embodiment, the average hollowness of the hollow particles is 70% or more and 85% or less.

  In one embodiment, the average particle diameter of the hollow particles is 2 μm or more and 10 μm or less.

  In one embodiment, the content ratio of the binder material and the hollow particles in the heat insulating layer (the content of the binder material / the content of the hollow particles) is 20/80 or more and less than 80/20 on a mass basis.

  In one embodiment, the thickness of the substrate is 20 μm or more and 200 μm or less.

  In one embodiment, the porosity of the substrate is 5% or less.

  According to the present invention, it is possible to provide a thermal transfer image receiving sheet having high printing unevenness prevention, printing wrinkle prevention, folding wrinkle prevention and adhesive material adhesion prevention.

It is a schematic cross section of a thermal transfer image receiving sheet in one embodiment. It is a schematic cross section of a thermal transfer image receiving sheet in one embodiment. In an Example, it is a figure which shows the right black image formed on the receiving layer with which a thermal transfer image receiving sheet is provided. In an Example, it is a figure explaining the peeling method of the peeling base material from a printed matter.

(Thermal transfer image receiving sheet)
As shown in FIG. 1, the thermal transfer image receiving sheet 10 of the present invention includes a receiving layer 11, a heat insulating layer 12, a base material 13, an adhesive layer 14, and a peeling base material 15.
In one embodiment, as shown in FIG. 2, the thermal transfer image receiving sheet 10 of the present invention includes a release layer 16 between the adhesive layer 14 and the release substrate 15.

The thermal transfer image-receiving sheet of the present invention, the Martens hardness measured from the receiving layer side, characterized in that at 5N / mm ² or more 25 N / mm ² or less. Thereby, the printing unevenness prevention property and the printing wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.
More preferably, Martens hardness of the thermal transfer image-receiving sheet, 8N / mm ² or more 22N / mm ² or less, further preferably 10 N / mm ² or more 20 N / mm ² or less.
In the present invention, “Martens hardness” is one of the indices of hardness (hardness) of substances including industrial materials, and is a kind of scratch hardness.
In the present invention, Martens hardness is measured in accordance with ISO 14577-1 using an ultra-micro hardness tester “Picotender HM-500” manufactured by Fischer Instruments Co., Ltd.

  Hereinafter, each layer provided in the thermal transfer image receiving sheet of the present invention will be described.

(Receptive layer)
The receiving layer is a layer that receives the sublimable dye transferred from the dye layer provided in the thermal transfer sheet and maintains the formed image.

Receiving layer is polypropylene (PP), high density polyethylene (HDPE, density 0.941 g / cm ³ or more), medium density polyethylene (MDPE, density 0.925 g / cm ³ or more and less than 0.941 g / cm ³ ), low density Polyolefins such as polyethylene (LDPE, density less than 0.925 g / cm ³ ), linear low density polyethylene (LLDPE, density less than 0.925 g / cm ³ ) and polymethylpentene, polyvinyl chloride, polyvinyl alcohol (PVA), Polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, polyvinyl resins such as polyvinyl butyral and polyvinyl pyrrolidone (PVP), (meth) acrylic resins such as polyacrylate, polymethacrylate and polymethyl methacrylate, cellophane, cellulose acetate, Nitrocellulose Cellulose resins such as cellulose acetate propionate (CAP) and cellulose acetate butyrate (CAB), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene di Polyester such as methylene terephthalate, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, polyamide such as nylon 6 and nylon 6,6, polyimide such as polyimide and polyetherimide, polycarbonate, polystyrene, polyurethane, ionomer resin, etc. Resin material can be included. The receiving layer can contain two or more of the above resin materials.

  Although content of the said resin material in a receiving layer is not specifically limited, For example, it can be 80 mass% or more and 98 mass% or less.

In one embodiment, the receiving layer includes a release material. Thereby, releasability with a thermal transfer sheet can be improved.
Examples of the release material include solid waxes such as polyethylene wax, amide wax, and Teflon (registered trademark) powder, fluorine-based or phosphate-based surfactant, silicone oil, reactive silicone oil, and curable silicone oil. Examples include various modified silicone oils and various silicone resins. An oily oil can be used as the silicone oil, but a modified silicone oil is preferred. As the modified silicone oil, amino-modified silicone, epoxy-modified silicone, aralkyl-modified silicone, epoxy-aralkyl-modified silicone, alcohol-modified silicone, vinyl-modified silicone, and urethane-modified silicone can be preferably used. And epoxy-aralkyl-modified silicones are particularly preferred. The receiving layer can contain two or more types of the release materials.

  The content of the release material in the receiving layer is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 10% by mass or less. Thereby, releasability with a thermal transfer sheet can be improved more.

  Further, the receptive layer is a plastic material, filler, UV stabilizer, anti-coloring material, surfactant, fluorescent whitening material, matting material, deodorant material, flame retardant, as long as the properties of the present invention are not impaired. Additives such as materials, weathering materials, antistatic materials, yarn friction reducing materials, slip materials, antioxidant materials, ion exchange materials, dispersion materials, ultraviolet absorbers, and coloring materials such as pigments and dyes can be included.

  The thickness of the receiving layer is preferably from 0.5 μm to 20 μm, and more preferably from 1.0 μm to 10 μm. Thereby, the density of the image formed on the receiving layer can be improved.

  The receiving layer is obtained by dispersing or dissolving the above material in water or an appropriate solvent to form a coating liquid, which is a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method or a rod. It can be formed by applying on the heat insulating layer by a known means such as a coating method to form a coating film and drying it.

(Insulation layer)
The heat insulating layer contains a binder material and hollow particles, can reduce heat loss during image formation on the receiving layer, and can impart cushioning properties to the thermal transfer image-receiving sheet. Print wrinkle prevention can be improved.

  The content ratio of the binder material and the hollow particles in the heat insulating layer (the content of the binder material / the content of the hollow particles) is preferably greater than 20/80 and less than 80/20 on a mass basis. The ratio is more preferably 70/30 or less, and most preferably 40/60 or more and 60/40 or less. Thereby, the printing unevenness prevention property and the printing wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.

The porosity of the heat insulating layer is preferably 45% or more and 85% or less, and more preferably 50% or more and 80% or less. Thereby, the print wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.
In the present invention, the porosity is obtained by analyzing a cross-sectional SEM image of the heat insulating layer with image analysis software ImageJ and dividing the area of the void portion by the area of the void portion and the resin portion. Specifically, according to the image analysis software, a cross-sectional SEM image is binarized, a distribution map in which voids are displayed as black regions is obtained, and a void ratio is obtained by determining a ratio of the black region to a cross-sectional area. Can be measured.

Examples of the binder material included in the heat insulating layer include resin materials such as polyolefin, vinyl resin, (meth) acrylic resin, cellulose resin, polyester, polyamide, polycarbonate, polystyrene, polyurethane, and ionomer resin.
In addition to the above resin materials, gelatin and derivatives thereof, pullulan, dextran, dextrin, agar, κ-carrageenan, λ-carrageenan, ι-carrageenan, casein, xanthene gum, locust bean gum, alginic acid, and gum arabic Etc. can be used.
The heat insulating layer can contain two or more of the binder materials.

  The content of the resin material in the heat insulating layer is preferably 20% by mass or more and 80% by mass or less, and more preferably 25% by mass or more and 75% by mass or less. Thereby, the printing unevenness prevention property and the printing wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.

The hollow particles may be organic hollow particles composed of a resin material or the like, or inorganic hollow particles composed of glass or the like, but from the viewpoint of dispersibility, organic hollow particles are preferable. .
Examples of the resin material constituting the organic hollow particles include (meth) acrylic resin, phenol resin, fluororesin, polyamide, polystyrene, polyimide, polycarbonate, and polyether.
The hollow particles may be expanded particles or non-expanded particles.
In addition, the heat insulation layer can contain 2 or more types of the said hollow particle.

The average particle diameter of the hollow particles is preferably 2 μm or more and 10 μm or less, more preferably 2 μm or more and 8 μm or less, and further preferably 3 μm or more and 5 μm or less. Thereby, the printing wrinkle prevention property of a thermal transfer image receiving sheet can be improved, maintaining the dispersibility in the heat insulation layer of a hollow particle. Furthermore, the image density formed on the receiving layer can be improved.
In the present invention, the average particle diameter of the hollow particles means a 50% particle diameter (D50 median diameter) when the particles in the solution are measured by a dynamic light scattering method and the particle diameter distribution is represented by a volume cumulative distribution. To do. The average particle size is measured using, for example, a Microtrac particle size analyzer or Nanotrac particle size analyzer manufactured by Nikkiso Co., Ltd.

The average hollowness of the hollow particles is preferably 70% or more and 87% or less, and more preferably 75% or more and 85% or less. Thereby, the printing unevenness prevention property and the printing wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.
In the present invention, the average hollow ratio can be calculated as follows.
First, an aqueous dispersion in which hollow particle components are dispersed in water is prepared, and the aqueous dispersion of hollow particles is dried to obtain a dried body.
Next, using a transmission electron microscope (manufactured by Hitachi High-Technologies Corporation), the particles constituting the hollow particle component in the dried body were observed (100 particles), and the diameter (inner diameter) on the inner surface side of these particles was measured. The average of these is the average particle inner diameter.
The volume of the hollow portion is determined from the average particle inner diameter, and the value is divided by the apparent volume of the particle calculated from the average particle diameter (particle outer diameter) and multiplied by 100 to calculate the average hollow ratio. .

In one embodiment, the hollow particles can be produced by encapsulating a foam material such as butane gas in resin particles or the like and heating and foaming.
Commercially available hollow particles may be used.

  The content of the hollow particles in the heat insulating layer is preferably 20% by mass or more and 80% by mass or less, and more preferably 30% by mass or more and 70% by mass or less. Thereby, the printing unevenness prevention property and the printing wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.

  The heat insulating layer can contain the above-mentioned additive as long as the properties of the present invention are not impaired.

  The thickness of the heat insulating layer is preferably 10 μm or more and 20 μm or less, more preferably 11 μm or more and 17 μm or less, and further preferably 12 μm or more and 15 μm or less. Thereby, the print wrinkle prevention property of the thermal transfer image receiving sheet can be improved. Furthermore, the image density formed on the receiving layer can be improved.

  The heat insulating layer is obtained by dispersing or dissolving the above materials in water or a suitable solvent to form a coating liquid, which is a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method, and a rod. It can be formed by applying on a substrate by a known means such as a coating method to form a coating film and drying it.

(Base material)
Thermal transfer image-receiving sheet comprises a substrate of the present invention has a density, and equal to or less than 0.70 g / cm ³ or more 1.60 g / cm ^3. Thereby, it is possible to improve the crease prevention property and the adhesive material adhesion prevention property of the thermal transfer image receiving sheet.
More preferably, the density of the base material is not more than 0.80 g / cm ³ or more 1.50 g / cm ^3, it is further 0.90 g / cm ³ or more 1.40 g / cm ³ or less.
In addition, the density of a base material is a value which can be calculated | required by remove | dividing the basic weight of a base material with the thickness of a base material.

As the substrate, a resin film containing a resin material such as polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin, polyimide, cellulose resin, polystyrene, polycarbonate, or ionomer resin can be used.
Moreover, if the said density conditions are satisfy | filled, the porous resin film which has a fine space | gap inside can be used.
However, from the viewpoint of preventing adhesion of the adhesive material, the base material preferably has no fine voids inside, and the porosity is preferably 5% or less, more preferably 3% or less. preferable.

  The base material can contain the above-mentioned additive as long as the characteristics of the present invention are not impaired.

  When a resin film is used as the substrate, the resin film may be a uniaxially stretched film or a biaxially stretched film.

  The surface of the base material is preferably subjected to surface treatment such as corona treatment, flame treatment, plasma treatment or flame treatment in order to improve adhesion with adjacent layers.

  The thickness of the substrate is preferably 20 μm or more and 200 μm or less, and preferably 30 μm or more and 150 μm or less. Thereby, the heat resistance at the time of printing can be secured, and the ease of peeling of the peeling substrate can be improved.

(Adhesive layer)
The thermal transfer image-receiving sheet of the present invention includes an adhesive layer on the surface opposite to the surface on which the heat insulating layer of the substrate is provided.

  In one embodiment, the adhesive layer is made of one or two adhesive materials such as a (meth) acrylic adhesive material, an epoxy adhesive material, a polyamide adhesive material, a polystyrene adhesive material, a silicone adhesive material, and a urethane adhesive material. Contains more than species.

  The content of the adhesive material in the adhesive layer is preferably 50% by mass or more, and more preferably 70% by mass or more. Thereby, the adhesiveness of an adhesion layer can be made favorable.

  In one embodiment, the pressure-sensitive adhesive layer contains the additive as long as the characteristics of the present invention are not impaired.

  The adhesive layer is obtained by dispersing or dissolving the above material in water or a suitable solvent to obtain a coating liquid, which is a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method, and It can be formed by applying on a substrate by a known means such as a rod coating method to form a coating film and drying it.

(Peeling substrate)
The thermal transfer image-receiving sheet of the present invention can be provided with a release substrate on the surface opposite to the surface of the adhesive layer that contacts the substrate, so that the adhesive layer can be peeled off. Can be prevented.

  As release substrates, paper substrates such as fine paper, art paper, coated paper, resin coated paper, cast coated paper, paperboard, synthetic paper and impregnated paper, polyester, polyamide, polyolefin, vinyl resin, (meth) acrylic resin A resin film composed of polyimide, cellulose resin or the like can be used.

  The thickness of the release substrate is preferably 30 μm or more and 200 μm or less, and preferably 50 μm or more and 150 μm or less. Thereby, a peeling base material can be more easily peeled from the adhesion layer, and it can prevent that a wrinkle (henceforth peeling wrinkle) generate | occur | produces in the adhesion layer at the time of peeling.

  A peeling base material can be laminated | stacked on a base material through an adhesion layer.

(Release layer)
The thermal transfer image receiving sheet of the present invention can include a release layer between the adhesive layer and the release substrate. The release layer is a layer that peels from the adhesive layer together with the release substrate when the release substrate is peeled off. By providing the release layer, the adhesive force between the release substrate and the adhesive layer can be adjusted, and the release wrinkle can be adjusted. Can be prevented.

  In one embodiment, the release layer includes resin materials such as (meth) acrylic resin, polyurethane, acetal resin, polyamide, polyester, melamine resin, polyol resin, cellulose resin, and silicone resin. A silicone resin is particularly preferable from the viewpoint of releasability.

  In one embodiment, the release layer includes a release material such as silicone oil, phosphate plasticizer, fluorine compound, wax, metal soap, and filler.

  Although the thickness of a mold release layer is not specifically limited, For example, it can be 0.1 micrometer or more and 2.0 micrometers or less.

  The release layer is obtained by dispersing or dissolving the above material in water or a suitable solvent to obtain a coating liquid, which is a roll coating method, reverse roll coating method, gravure coating method, reverse gravure coating method, bar coating method. And it can form by apply | coating on a peeling base material by well-known means, such as a rod coat method, forming a coating film, and drying this.

  EXAMPLES Next, although an Example is given and this invention is demonstrated still in detail, this invention is not limited to these Examples. In addition, unless otherwise described below, the content, blending ratio, and the like are based on mass.

Example 1
A 75 μm-thick PET film (Diafoil (registered trademark) S100, density: 1.40 g / cm ³ ) having a thickness of 75 μm was prepared as a base material. The forming coating solution was applied and dried to form a heat insulating layer having a thickness of 12 μm.
(Coating liquid for heat insulation layer formation)
-267 parts by mass of (meth) acrylic resin (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
・ 220 parts by mass of hollow particles (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ Isopropanol (IPA) 129 mass parts ・ Water 301 mass parts

On the heat insulating layer, a receiving layer-forming coating solution having the following composition was applied and dried to form a receiving layer having a thickness of 4 μm.
(Receptive layer forming coating solution)
-12 parts by mass of vinyl chloride-vinyl acetate copolymer (manufactured by Nissin Chemical Industry Co., Ltd., Solvein (registered trademark) C)
・ 0.8 parts by mass of epoxy-modified silicone (Shin-Etsu Chemical Co., Ltd., X-22-3000T)
Amino-modified silicone 0.24 parts by mass (Shin-Etsu Chemical Co., Ltd., X-22-1660B-3)
・ Toluene 30 parts by mass ・ Methyl ethyl ketone (MEK) 30 parts by mass

A pressure-sensitive adhesive layer-forming coating solution having the following composition is applied to the other surface of the base material and dried to form a pressure-sensitive adhesive layer having a thickness of 10 μm. Porous PET film (Toyobo Co., Ltd., Crisper (registered trademark) film, density: 1.1 g / cm ³ ) was laminated to obtain a thermal transfer image-receiving sheet.
(Coating liquid for forming adhesive layer)
・ 48 parts by weight of (meth) acrylic adhesive (manufactured by Soken Chemical Co., Ltd., SK Dine 1310L)
・ 0.36 parts by mass of epoxy adhesive (manufactured by Soken Chemical Co., Ltd., hardener E-AX)
・ Ethyl acetate 51.64 parts by mass

Example 2
Thermal transfer image receiving in the same manner as in Example 1 except that the base material was changed to a biaxially stretched PP film (Futamura Chemical Co., Ltd., FOS-BT, density: 0.91 g / cm ³ ) with a thickness of 30 μm. A sheet was produced.

Example 3
Thermal transfer image receiving in the same manner as in Example 1 except that the substrate was changed to a porous PET film having a thickness of 35 μm (Lumirror (registered trademark), manufactured by Toray Industries, Inc., density: 1.05 g / cm ³ ). A sheet was produced.

Example 4
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the composition of the heat-insulating layer-forming coating solution was changed as follows.
(Coating liquid for heat insulation layer formation)
・ 133 parts by mass of (meth) acrylic resin (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
-385 parts by mass of hollow particles (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ IPA 129 mass parts ・ Water 301 mass parts

Example 5
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the composition of the heat-insulating layer-forming coating solution was changed as follows.
(Coating liquid for heat insulation layer formation)
-311 parts by mass of (meth) acrylic resin (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
・ 165 parts by mass of hollow particles (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ IPA 129 mass parts ・ Water 301 mass parts

Comparative Example 1
Thermal transfer image receiving in the same manner as in Example 1 except that the substrate was changed to a 35 μm thick porous PP film (manufactured by Mitsui Chemicals, Inc., SP-U, density: 0.63 g / cm ³ ). A sheet was produced.

Comparative Example 2
The substrate was changed to a biaxially stretched PP film with a thickness of 30 μm (Futamura Chemical Co., Ltd., FOS-BT, density: 0.91 g / cm ³ ), and the thickness of the heat insulating layer was changed to 8 μm. Were similar to Example 1 to produce a thermal transfer image receiving sheet.

Comparative Example 3
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the composition of the heat-insulating layer-forming coating solution was changed as follows.
(Coating liquid for heat insulation layer formation)
・ 88 parts by weight of (meth) acrylic resin (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
・ 440 parts by mass of hollow particles (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ IPA 129 mass parts ・ Water 301 mass parts

Comparative Example 4
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the composition of the heat-insulating layer-forming coating solution was changed as follows.
(Coating liquid for heat insulation layer formation)
-(Meth) acrylic resin 356 parts by mass (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
・ Hollow particles 110 parts by mass (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ IPA 129 mass parts ・ Water 301 mass parts

Comparative Example 5
While changing a base material into a 35-micrometer-thick porous PP film (Mitsui Chemicals Tosero Co., Ltd., SP-U, density: 0.63 g / cm < ³ >), the composition of the coating liquid for heat insulation layer formation is the following A thermal transfer image-receiving sheet was produced in the same manner as in Example 1 except that the above was changed.
(Coating liquid for heat insulation layer formation)
-267 parts by mass of (meth) acrylic resin (manufactured by Nippon Zeon Co., Ltd., SX1707A, solid content 45% by mass)
・ 220 parts by mass of hollow particles (average particle size 3 μm, hollow rate 80%, solid content 36% by mass)
・ Surfactant 2 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., Dynol (registered trademark) 604)
・ IPA 129 mass parts ・ Water 301 mass parts

<< Measurement of Martens hardness >>
The Martens hardness of the receiving layer included in the thermal transfer image-receiving sheet obtained in the above Examples and Comparative Examples was measured and summarized in Table 1. For the measurement of Martens hardness, an ultra-micro hardness tester “Pico Tender HM-500” manufactured by Fischer Instruments Co., Ltd. was used, and the measurement conditions were as follows.
(Measurement condition)
・ Temperature: 25 ℃
・ Relative humidity: 50%
・ Maximum test load: 500mN
・ Maximum depth: 150μm
・ Loading time: 5 seconds

<< Measurement of porosity >>
The cross-sectional SEM images of the heat-insulating layers included in the thermal transfer image-receiving sheets of Examples and Comparative Examples are analyzed by image analysis software ImageJ, and the porosity (the area of the void portion / the area of the void portion and the resin portion) is obtained. Table 1 Summarized in

<< Print wrinkle prevention evaluation >>
A sublimation type thermal transfer printer (Dai Nippon Printing Co., Ltd., DS40) and a genuine thermal transfer sheet of the printer (Dai Nippon Printing Co., Ltd.) are provided on the receiving layer of the thermal transfer image receiving sheet obtained in each example and each comparative example. (1) black solid image (0/255 gradation image), (2) right black image (see FIG. 3) and (3) half gray solid image (128/255 gradation image), Each of the 5 sheets (15 sheets in total) was formed under the following conditions, and cut in the TD direction by a cutting mechanism provided in the sublimation type thermal transfer printer to produce a 6 inch (TD direction) × 4 inch (MD direction) printed matter. .
The printed matter was visually observed, and the print wrinkle resistance was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
A: Print wrinkles were not confirmed in all images.
B: (2) Print wrinkles were confirmed only in the right black image, but there was no practical problem.
NG: In addition to (2) the right black image, printing wrinkles were confirmed in at least one of (1) a black solid image and (3) a half gray solid image.
(Image formation conditions)
-Heating element average resistance: 5300Ω
・ Print density in the main scanning direction: 300 dpi
-Sub-scanning direction printing density: 300 dpi
・ Printing power: 0.10W / dot
-Line cycle: 0.5 msec. / Line
・ Printing start temperature: 32 ℃

<< Evaluation of printing unevenness prevention >>
The occurrence of unevenness in the (3) half gray solid image formed as described above was visually confirmed, and the printing unevenness prevention property was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: Unevenness was not confirmed.
B: Mild unevenness was confirmed, but there was no practical problem.
NG: Unevenness was confirmed.

<< Adhesive adhesion prevention >>
On the receiving layer provided in the thermal transfer image-receiving sheet obtained in Example 1, (1) a black solid image was formed in the same manner as described above, and 10,000 prints were repeatedly produced. After the printed matter was prepared, the adhesion of the adhesive material to the cutter included in the cutter mechanism included in the sublimation type thermal transfer printer was visually confirmed, and the adhesive material adhesion preventing property was evaluated based on the following evaluation criteria. The thermal transfer image-receiving sheets obtained in other examples and comparative examples were similarly evaluated, and the evaluation results are shown in Table 1.
(Evaluation criteria)
A: Adhesion of the adhesive material was hardly seen.
B: Although adhesion of the adhesive material was slightly observed, there was no practical problem.
NG: Adhesive material was often adhered, and there was a problem in practical use.

<<< Evaluation for preventing wrinkling >>>
As described above, (3) after forming a half-gray image on the thermal transfer image-receiving sheets obtained in the examples and comparative examples, as shown in FIG. The surface of the printed product after peeling was observed with the naked eye, and the crease prevention property was evaluated based on the following evaluation criteria. The evaluation results are shown in Table 1.
(Evaluation criteria)
A: No creases were observed on the surface of the printed material.
NG: Wrinkles were confirmed on the surface of the printed material.

<< Image density evaluation >>
(1) The OD value (optical density) of the black solid image formed as described above was measured using an optical densitometer (X-rite, i1-pro2, Ansi-A, D65 light source, measurement angle 2 °, no filter). The image density was evaluated based on the following evaluation criteria. The evaluation results are summarized in Table 1.
(Evaluation criteria)
A: The OD value was 2.1 or more.
B: The OD value was 2.0 or more and less than 2.1.
C: The OD value was less than 2.0.

Explanation of sign

10: Thermal transfer image receiving sheet 11: Receptive layer 12: Heat insulation layer 13: Base material 14: Adhesive layer 15: Peeling base material 16: Release layer

Claims (8)

A receiving layer, a heat insulating layer containing a binder material and hollow particles, a base material, an adhesive layer, and a release base material,
Density of the base material is not more than 0.70 g / cm ³ or more 1.60 g / cm ^3,
The Martens hardness measured from the receiving layer side, characterized in that at 5N / mm ² or more 25 N / mm ² or less, a thermal transfer image-receiving sheet.   The thermal transfer image receiving sheet according to claim 1, wherein the heat insulating layer has a porosity of 45% or more and 85% or less.   The thermal transfer image receiving sheet according to claim 1 or 2, wherein the heat insulating layer has a thickness of 10 µm or more and 20 µm or less.   The thermal transfer image receiving sheet according to any one of claims 1 to 3, wherein an average hollowness ratio of the hollow particles is 70% or more and 85% or less.   The thermal transfer image receiving sheet according to any one of claims 1 to 4, wherein an average particle diameter of the hollow particles is 2 µm or more and 10 µm or less.   The content ratio (content of binder material / content of hollow particles) of the binder material and the hollow particles in the heat insulating layer is 20/80 or more and less than 80/20 on a mass basis. The thermal transfer image receiving sheet according to any one of 5.   The thermal transfer image receiving sheet according to any one of claims 1 to 6, wherein the thickness of the substrate is 20 µm or more and 200 µm or less.   The thermal transfer image receiving sheet according to any one of claims 1 to 7, wherein the porosity of the substrate is 5% or less.

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