JP7157924B2 - thermal transfer image receiving sheet - Google Patents

Description

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

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

In this sublimation-type thermal transfer method, a thermal transfer sheet having a dye layer containing a sublimation dye and a thermal transfer image-receiving sheet having a receiving layer are superimposed, and then the thermal transfer sheet is heated by a thermal head provided in a thermal transfer printer. , the sublimable dye in the dye layer is transferred to the receiving layer of the thermal transfer image receiving sheet, and an image is formed to obtain a print.

By the way, in recent years, a seal-type thermal transfer image-receiving sheet has been widely known. A receiver sheet has been proposed.

A conventional thermal transfer image-receiving sheet as proposed in Patent Document 1 is easily affected by the surrounding environment, and especially when left in a humid environment, the adhesiveness is remarkably reduced. had been

In addition, the seal-type thermal transfer image-receiving sheet is sometimes required to have re-adhesiveness, which means that it can be peeled off after being attached to an object, and can be attached again after changing the attaching position or the object. However, when the conventional thermal transfer image-receiving sheet is peeled off, part of the thermal transfer image-receiving sheet, particularly the adhesive layer and the paper base material, remains on the object, resulting in a decrease in adhesive strength or non-adhesiveness. I could have lost it.

In addition, the thermal transfer image receiving sheet is transported in the thermal transfer printer by a pair of transport rollers, a pinch roller, and a capstan roller in contact with the release base material of the thermal transfer image receiving sheet. When this occurs, printing misalignment (misalignment between the image forming position and the intended image forming position) occurs, so the thermal transfer image receiving sheet is required to have high transportability.
Furthermore, when a thermal transfer image-receiving sheet having a paper base material is used, paper dust tends to adhere to the capstan roller, reducing the transportability of the thermal transfer image-receiving sheet and possibly causing print misalignment. There has been a demand for the development of a thermal transfer image-receiving sheet which is less susceptible to contamination of conveying rollers.

Further, the thermal transfer image-receiving sheet is generally required to have anti-curl properties to prevent curling in the printed matter in order to improve the quality of the produced printed matter.

JP 2007-229986 A

The present invention has been made in view of the above problems, and the problem to be solved is a thermal transfer image-receiving sheet which has high adhesion maintenance properties, re-adhesion properties, conveyability and anti-curl properties, and low contamination of conveying rollers. is to provide

The thermal transfer image-receiving sheet of the present invention comprises a receiving layer, a paper substrate, a core substrate, an adhesive layer, and a release substrate,
The core substrate is a resin layer having a thickness of 5 μm or more,
The release substrate is composed of a resin film or a porous resin film,
The sum of the breaking strengths of the core substrate, the adhesive layer and the release substrate is 70N or more and 200N or less.

In one embodiment, the sum of the breaking strengths of the core substrate, the adhesive layer and the release substrate is 100N or more and 200N or less.

In one embodiment, the sum of the breaking strengths of the core substrate, the adhesive layer and the release substrate is 150N or more and 200N or less.

In one embodiment, the thickness of the core substrate is 10 μm or more and 45 μm or less.

In one embodiment, the release substrate has a thickness of 15 μm or more and 100 μm or less.

In one embodiment, the release substrate is composed of a porous resin film.

In one embodiment, the thermal transfer image receiving sheet of the present invention comprises a porous layer between the receiving layer and the paper substrate.

In one embodiment, the thermal transfer image-receiving sheet of the present invention comprises a release layer between the adhesive layer and the release substrate.

According to the present invention, there is provided a thermal transfer image-receiving sheet which has high adhesion maintenance properties, re-adhesion properties, transportability and anti-curl properties, and low contamination of transport rollers.

1 is a schematic cross-sectional view of a thermal transfer image-receiving sheet in one embodiment; FIG. 1 is a schematic cross-sectional view of a thermal transfer image-receiving sheet in one embodiment; FIG. 1 is a schematic cross-sectional view of a thermal transfer image-receiving sheet in one embodiment; FIG. 1 is a schematic cross-sectional view of a thermal transfer image-receiving sheet in one embodiment; FIG.

(Thermal transfer image receiving sheet)
The thermal transfer image-receiving sheet 10 of the present invention, as shown in FIG.
In one embodiment, the thermal transfer image receiving sheet 10 also has a porous layer 16 between the receiving layer 11 and the paper substrate 12, as shown in FIG.
In one embodiment, the thermal transfer image-receiving sheet 10 includes a release layer 17 between the adhesive layer 14 and the release substrate 15, as shown in FIG.
In one embodiment, the thermal transfer image receiving sheet 10 also includes a primer layer 18 between the receiving layer 11 and the porous layer 16, as shown in FIG.
Furthermore, in one embodiment, the thermal transfer image-receiving sheet 10 comprises an adhesive layer between any interlayers, such as between the paper substrate and the core substrate, between the paper substrate and the porous layer, and the like. (not shown).

The present invention is characterized in that the sum of the breaking strengths of the core substrate, the adhesive layer and the release substrate is 70N or more and 200N or less. This makes it possible to improve readhesion, conveyability and anti-curl properties of the thermal transfer image-receiving sheet, and reduce contamination of the conveying roller.
The breaking strength is preferably 100N or more and 200N or less, more preferably 150N or 200N or less.
In the present invention, the breaking strength is measured using a tensile tester (Automatic film strength and elongation measuring device Tensilon (registered trademark) AMF/RTA-100 manufactured by Orientec Co., Ltd.) in accordance with JIS K 7127, at a tensile speed of 200 mm. /min.
The sum of the breaking strengths of the core base material, the adhesive layer and the release base material may be obtained by separately measuring the breaking strengths of each. The breaking strength of a laminate comprising a core substrate, an adhesive layer, and a release substrate obtained by peeling and drying may be measured.
Further, the above water impregnation may be performed after only the receiving layer is wiped off with a solvent or the like or removed by peeling.

Each layer included in the thermal transfer image-receiving sheet of the present invention will be described below.

(receptive layer)
The receiving layer is a layer that receives the sublimation dye that migrates from the dye layer of the thermal transfer sheet and maintains the formed image.

The receptive layer contains at least one resin material, and the resin material can be used without particular limitation as long as it has receptivity for sublimation dyes. Examples include polyethylene terephthalate (PET) and polybutylene terephthalate. (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, polyesters such as terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, polyamides such as nylon 6 and nylon 6,6, polypropylene (PP), polyolefins such as polyethylene (PE) and polymethylpentene, polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, vinyls such as polyvinyl butyral and polyvinylpyrrolidone (PVP) Resins, (meth)acrylic resins such as polyacrylates, polymethacrylates and polymethyl methacrylates, imide resins such as polyimides and polyetherimides, cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP) and cellulose acetate Examples include cellulose resins such as butyrate (CAB), styrene resins, polycarbonates, and ionomer resins.

The content of the resin material in the receiving layer is not particularly limited, and can be 80% by mass or more and 98% by mass or less.

In one embodiment, the receptive layer includes a release material. Thereby, the releasability from the thermal transfer sheet can be improved.
Examples of release materials include solid waxes such as polyethylene wax, amide wax, and Teflon (registered trademark) powder, fluorine-based or phosphate ester-based surfactants, silicone oil, reactive silicone oil, curable silicone oil, and the like. Examples include various modified silicone oils and various silicone resins. Although an oily silicone oil can be used as the silicone oil, 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, urethane-modified silicone, etc. can be preferably used. , epoxy-aralkyl-modified silicones are particularly preferred. The receiving layer can contain two or more 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, more preferably 0.5% by mass or more and 10% by mass or less. Thereby, mold releasability can be further improved.

In addition, the receiving layer contains a releasing agent, a plasticizer, a filler, an ultraviolet stabilizer, an anti-coloring agent, a surfactant, a fluorescent whitening agent, a matting agent, and a deodorizing agent, as long as the characteristics of the present invention are not impaired. Additives such as flame retardants, weather resistant materials, antistatic materials, thread friction reducing materials, slip materials, antioxidants, ion exchange materials, dispersion materials, ultraviolet absorbers, and coloring materials such as pigments and dyes may be included. can.

The thickness of the receiving layer is preferably 0.5 μm or more and 20 μm or less, more preferably 1 μm or more and 10 μm or less. Thereby, the density of the image formed on the receiving layer can be improved.

The receiving layer is prepared by dispersing or dissolving the above materials in water or an appropriate solvent to form a coating liquid, which is applied by roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. It can be formed by coating a paper substrate, a porous layer or a primer layer by a known means such as a coating method to form a coating film, and drying the film.

(Paper substrate)
Examples of paper substrates include coated paper such as art paper, coated paper, matt coated paper, resin coated paper, cast coated paper, kraft paper and baryta paper, fine paper, medium quality paper, paperboard, impregnated paper, and vapor deposition. Paper, acid paper as well as neutral paper and the like can be used.
Among these, coated paper is preferable, and coated paper is more preferable, for the reason of coexistence of dimensional stability and formation.
In the present invention, the term "coated paper" refers to information paper such as medium-quality paper coated with a paint having a thickness of 10 μm or more and 30 μm or less on at least one surface thereof.

The surface of the paper substrate is preferably subjected to a surface treatment such as corona treatment, flame treatment, plasma treatment, flame treatment, etc., in order to improve adhesion with adjacent layers.

The thickness of the paper substrate is 90 μm or more and 150 μm or less, more preferably 10 μm or more and 140 μm or less. Thereby, the anti-curling property of the thermal transfer image-receiving sheet can be further improved.

(core base material)
The core base material contains at least one resin material, and includes polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate and ionomer resin. Among them, polyester and polyolefin are preferred, and PET and PP are more preferred, from the viewpoints of adhesive strength maintenance, re-adhesion, transportability, anti-curling properties, and transport roller contamination of the thermal transfer image-receiving sheet.

The content of the resin material in the core substrate is preferably 50% by mass or more and 98% by mass or less, more preferably 70% by mass or more and 95% by mass or less. This makes it possible to further improve the adhesive force retention, re-adhesiveness, transportability and anti-curling properties of the thermal transfer image-receiving sheet, and to further reduce the transport roller contamination.

The core base material can contain the above-described additives as long as the characteristics of the present invention are not impaired.

It is preferable that the surface of the core base material is subjected to the above-mentioned surface treatment in order to improve the adhesion with the adjacent layer.

In the thermal transfer image-receiving sheet of the present invention, the core substrate has a thickness of 5 μm or more. This makes it possible to improve readhesion and anti-curl properties of the thermal transfer image-receiving sheet, and reduce contamination of the conveying roller. In addition, from the viewpoint of the adhesive strength maintenance property, re-adhesion property, transportability, anti-curl property, and transport roller contamination property of the thermal transfer image-receiving sheet, the thickness of the core substrate is preferably 10 μm or more and 45 μm or less. It is more preferably 15 μm or more and 40 μm or less.

In one embodiment, the core substrate is a resin film obtained by forming a film from the above material by a T-die method, an inflation method, or the like, or a commercially available resin film on a paper substrate via an adhesive layer described below. can be formed by laminating to

When the core substrate is formed using a resin film, the resin film may be a uniaxially or biaxially stretched film or an unstretched film. It is preferable to use a stretched film because it can sufficiently satisfy the strength and heat resistance required in production.

In one embodiment, the corrugating medium can also be formed by melt extruding the above materials onto a paper substrate.

(adhesive layer)
In one embodiment, the adhesive layer contains at least one adhesive, such as (meth)acrylic adhesive, epoxy adhesive, polyamide adhesive, polystyrene adhesive, silicone adhesive, and urethane adhesive. Adhesive materials and the like can be mentioned.

The content of the adhesive material in the adhesive layer is preferably 50% by mass or more, more preferably 70% by mass or more. This makes it possible to improve the adhesiveness of the adhesive layer.

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

The thickness of the adhesive layer is preferably 1 μm or more and 15 μm or less, more preferably 5 μm or more and 13 μm or less. Thereby, the adhesiveness of the adhesive layer can be improved.

The adhesive layer is formed by dispersing or dissolving the above material in water or an appropriate solvent to form a coating liquid, which is applied by a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, a bar coating method and a It can be formed by coating a core base material, a release base material, or a release layer by a known means such as a rod coating method to form a coating film, and drying the film.

(Release base material)
The release substrate is composed of a resin film or porous resin film composed of polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, imide resin, cellulose resin, or the like. A porous resin film is preferable because it can be easily cut into a print having a desired size after an image is formed on the receiving layer of the thermal transfer image-receiving sheet of the present invention.

When the release substrate is a porous resin film, its density is preferably 0.3 g/cm ³ or more and 2 g/cm ³ or less, and 0.5 g/cm ³ or more and 1.4 g/cm ³ or less. Preferably. Thereby, the ease of cutting can be further improved.
In addition, in this invention, the density of a film is measured based on JISK7112.

The porous resin film can be produced by a known method. For example, it can be produced by forming a film from a mixture obtained by kneading immiscible organic particles or inorganic particles with the above-described resin material. In one embodiment, the porous resin film can be produced by forming a film from a mixture containing a first resin material and a second resin material having a higher melting point than the first resin material. In this case, the second resin material functions as a core material that forms fine voids.
In addition, in the present invention, a commercially available porous resin film may be used.

The thickness of the release base material is preferably 15 μm or more and 100 μm or less, and preferably 30 μm or more and 70 μm or less. As a result, the transportability and anti-curling properties of the thermal transfer image-receiving sheet can be further improved, and the contamination of the transport roller can be further reduced. In addition, the release base material can be more easily peeled off from the adhesive layer, and the occurrence of wrinkles (hereinafter referred to as peel wrinkles) in the adhesive layer during peeling can be prevented.

The release base material can be laminated on the core base material via the adhesive layer.

(Porous layer)
In one embodiment, the thermal transfer image-receiving sheet of the present invention comprises a porous layer between the receiving layer and the paper substrate, thereby reducing heat loss during image formation and adding a cushion to the thermal transfer image-receiving sheet. properties and can form a better image on the receiving layer.

In one embodiment, the porous layer is composed of a porous resin film having microvoids therein and contains at least one resin material. Examples of resin materials include polyesters, polyamides, polyolefins, vinyl resins, (meth)acrylic resins, imide resins, cellulose resins, styrene resins, polycarbonates, and ionomer resins.
Among these, polyester and polyolefin are preferred, and PET and PP are more preferred, from the viewpoint of cost and processability.

The porous layer can contain the above additives as long as the properties of the present invention are not impaired.

In addition, the surface of the porous layer may be subjected to a surface treatment such as corona treatment in order to improve adhesion with adjacent layers.

The thickness of the porous layer is preferably 10 μm or more and 50 μm or less, and more preferably 15 μm or more and 45 μm or less. Thereby, the anti-curling property of the thermal transfer image-receiving sheet can be further improved. Also, a better image can be formed on the receiving layer.

In one embodiment, the porous layer can be laminated onto the paper substrate via the adhesive layer described below.

(release layer)
The thermal transfer image-receiving sheet of the present invention can have a release layer between the adhesive layer and the release substrate. The release layer is a layer that is released from the adhesive layer together with the release substrate when the release substrate is peeled off. By providing the release layer, the adhesion between the release substrate and the adhesive layer can be adjusted.

In one embodiment, the release layer includes a resin material such as (meth)acrylic resin, polyurethane, acetal resin, polyamide, polyester, melamine resin, polyol resin, cellulose resin, etc., and silicone resin. Silicone resins are particularly preferred from the standpoint of releasability.

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

The thickness of the release layer is not particularly limited, but can be, for example, 0.1 μm or more and 2 μm or less.

The release layer is formed by dispersing or dissolving the above material in water or an appropriate solvent to form a coating liquid, which is applied by a roll coating method, a reverse roll coating method, a gravure coating method, a reverse gravure coating method, or a bar coating method. and by a known means such as a rod coating method, to form a coating film on a release base material, which is then dried.

(primer layer)
In one embodiment, the thermal transfer image-receiving sheet of the present invention comprises a primer layer between the receiving layer and the porous layer. Thereby, the adhesion between these layers can be improved.

The primer layer contains at least one kind of resin material such as polyester, polyamide, polyolefin, vinyl resin, (meth)acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate and ionomer resin.

In one embodiment, the primer layer comprises layered silicate. This makes it possible to impart electrical conductivity to the primer layer and improve handling of printed matter.

In addition, the primer layer can contain the above-described additives within a range that does not impair the characteristics of the present invention.

The thickness of the primer layer is not particularly limited, and can be, for example, 0.1 μm or more and 5 μm or less.

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

(adhesion layer)
In one embodiment, the thermal transfer image-receiving sheet of the present invention comprises an adhesive layer between arbitrary layers.
The adhesive layer can contain at least one resin material, for example, vinyl resins such as polyvinyl acetate, PVB, ethylene-vinyl acetate copolymers and vinyl chloride-vinyl acetate copolymers, PE and PP. Polyolefins, polyesters such as PET and PBT, polyamides, imide resins, polyacrylates, (meth)acrylic resins such as polymethacrylate and polymethyl methacrylate, cellulose resins such as cellulose diastase, polyurethanes and two-pack curing resin materials, etc. mentioned.

The content of the resin material in the adhesive layer is preferably 50% by mass or more, more preferably 70% by mass or more. Thereby, the adhesion between layers can be improved.

In one embodiment, the adhesive layer contains an isocyanate compound, and examples thereof include polyisocyanates such as diisocyanate and triisocyanate. From the viewpoint of transparency, aromatic polyisocyanates are preferred.
Aromatic polyisocyanate is a terminal isocyanate group-containing compound (polyhydric alcohol adduct of aromatic diisocyanate) obtained by reacting an excess amount of diisocyanate compound with polyhydric alcohol. Examples of diisocyanate compounds include tolylene-2,6-diisocyanate, diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, tolidine diisocyanate, xylylene diisocyanate and tetramethylxylylene diisocyanate. Examples of polyhydric alcohols include , ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, ditrimethylolpropane and dipentaerythritol. The adhesive layer can contain two or more of the above isocyanate compounds.

The content of the isocyanate compound in the adhesive layer is adjusted so that the molar equivalent ratio (-NCO/-OH) between the isocyanate group of the isocyanate compound and the hydroxyl group of the resin material is 0.1 or more and 2.0 or less. is preferred.

The thickness of the adhesive layer is not particularly limited, but can be, for example, 1 μm or more and 10 μm or less.

The adhesive layer is formed by dispersing or dissolving the above materials in water or an appropriate solvent to form a coating liquid, which is applied by roll coating, reverse roll coating, gravure coating, reverse gravure coating, bar coating and rod coating. It can be formed by coating a paper substrate or the like by a known means such as a coating method to form a coating film, and drying the film.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. In addition, hereinafter, contents, compounding ratios, etc. are based on mass unless otherwise described.

Example 1
A stretched PP film A (HO402, manufactured by Waso Industri Co., Ltd.) with a thickness of 18 μm is prepared as a core substrate, and a coating solution for forming an adhesive layer having the following composition is applied to one surface of the film and dried. Then, an adhesive layer with a thickness of 2.5 μm is formed, and a coated paper with a thickness of 105 μm (Daio Paper Co., Ltd., Utrillo (registered trademark) Coat 127.9 ) was laminated.
(Coating liquid for forming adhesive layer)
・ Polyurethane 30 parts by mass (manufactured by Mitsui Chemicals, Inc., Takelac (registered trademark) A-969V)
- Isocyanate compound 10 parts by mass (manufactured by Mitsui Chemicals, Inc., Takenate (registered trademark) A-5)
・ Ethyl acetate 60 parts by mass

On the other side of the stretched PP film, a coating solution for forming an adhesive layer having the following composition was applied and dried to form an adhesive layer having a thickness of 10 µm.
(Coating liquid for forming adhesive layer)
・ (Meth) acrylic adhesive material 48 parts by mass (manufactured by Soken Chemical Co., Ltd., SK Dyne 1251)
・Epoxy adhesive material 0.36 parts by mass (manufactured by Soken Chemical Co., Ltd., curing material E-AX)
・Ethyl acetate 51.64 parts by mass

A 50 μm thick PET film A (Toyobo Ester (registered trademark) film E5000 manufactured by Toyobo Co., Ltd.) was prepared as a release substrate, and a release layer forming coating solution having the following composition was applied to one surface thereof. After coating and drying, a release layer having a thickness of 0.25 μm was formed to obtain a laminate of the release base material and the release layer.
Next, the release layer surface of the laminate and the adhesive layer surface of the laminate of the paper substrate, the core substrate and the adhesive layer were laminated.
(Coating liquid for forming release layer)
・ Silicone resin 100 parts by mass (Shin-Etsu Chemical Co., Ltd., KS-847H)
・Toluene 200 parts by mass

Next, on the other surface of the paper substrate, the adhesive layer-forming coating liquid having the above composition is applied and dried to form an adhesive layer having a thickness of 2.5 μm. A porous PET film (Lumirror (registered trademark) 35ED0S, manufactured by Toray Industries, Inc.) having a thickness of 35 μm was laminated as a substrate.

A coating solution for forming a primer layer having the following composition was applied onto the porous layer and dried to form a primer layer having a thickness of 1 μm.
(Coating liquid for forming primer layer)
- Polyester 10 parts by mass (manufactured by Nippon Synthetic Chemical Co., Ltd., polyester (registered trademark) WR905)
・ 10 parts by mass of conductive synthetic layered silicate (Laponite JS, manufactured by Wilper Ellis Co., Ltd.)
・Water 80 parts by mass

On the primer 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 to obtain a thermal transfer sheet.
(Coating solution for forming receptor layer)
・Vinyl chloride-vinyl acetate copolymer 12 parts by mass (manufactured by Nissin Chemical Industry Co., Ltd., Solbin (registered trademark) C)
・ 0.8 parts by mass of epoxy-modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-3000T)
· Amino-modified silicone 0.24 parts by mass (manufactured by Shin-Etsu Chemical Co., Ltd., X-22-1660B-3)
・30 parts by mass of toluene ・30 parts by mass of methyl ethyl ketone (MEK)

Examples 2-9 and Comparative Examples 1-4
A thermal transfer image-receiving sheet was produced in the same manner as in Example 1, except that at least one of the core substrate and the release substrate used was changed to the resin film shown in Table 1.
The details of the resin film are as follows.
(core base material)
· PET film B: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5001, thickness 19 μm
・ PET film C: SB100, thickness 12 μm, manufactured by Hwasung Industry Co., Ltd.
・ PP film B: FOS-BT manufactured by Futamura Chemical Co., Ltd., thickness 30 μm
・ PP film C: SJ303, thickness 12 μm, manufactured by Hwasung Industry Co., Ltd.
・ PP film D: FOS-BT manufactured by Futamura Chemical Co., Ltd., thickness 50 μm
・ PET film D: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5000, thickness 50 μm
・PET film E: manufactured by Toray Industries, Inc., Lumirror (registered trademark) F53, thickness 4.5 μm
(Release base material)
・ PET film F: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5000, thickness 38 μm
- PET film G: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5001, thickness 25 μm
· PET film H: manufactured by Toyobo Co., Ltd., Toyobo Ester (registered trademark) film E5001, thickness 19 μm
・Porous PET film: Crisper (registered trademark) K1212, thickness 38 μm, manufactured by Toyobo Co., Ltd.

Comparative example 5
Thermal transfer image receiving in the same manner as in Example 1, except that a core substrate is not provided, an adhesive layer is formed on a paper substrate, and a laminate of a release layer and a release substrate is laminated via this. A sheet was produced.

<<breaking strength measurement>>
The thermal transfer image-receiving sheets of the above Examples and Comparative Examples are prepared, the thermal transfer image-receiving sheets are immersed in water, the receiving layer and the paper substrate are peeled off together, and dried in an environment of 25° C. and a relative humidity of 10%. rice field.
The thus obtained laminate consisting of the core base material, the adhesive layer and the release base material was cut into a size of 10 mm in width and 150 mm in length to obtain a test piece, and a tensile tester (Orientec Co., Ltd.) Using an automatic film strength and elongation measuring device Tensilon (registered trademark) AMF/RTA-100)), the load at which the test piece breaks was measured in accordance with JIS K 7127 at a tensile speed of 200 mm/min. Table 1 summarizes the measurement results.

<<Adhesive strength maintenance evaluation>>
The thermal transfer image-receiving sheets obtained in the above Examples and Comparative Examples were allowed to stand in an environment of 40° C. and a relative humidity of 90%. After standing, the thermal transfer image-receiving sheet was visually observed and evaluated based on the following evaluation criteria. Table 1 summarizes the evaluation results.
(Evaluation criteria)
A: No peeling was observed between the laminate of the paper substrate, the core substrate and the adhesive layer and the laminate of the release substrate and the release layer (between the adhesive layer and the release layer). rice field.
NG: Peeling was observed between the adhesive layer and the release layer.

<< Readhesion evaluation >>
The release substrate included in the thermal transfer image-receiving sheets obtained in the above Examples and Comparative Examples was peeled off and attached to a stainless steel (SUS) plate in an environment of 25° C. and a relative humidity of 50%. After the thermal transfer image-receiving sheet was attached to the SUS plate and allowed to stand for 24 hours, the thermal transfer image-receiving sheet was peeled off. The peeled thermal transfer image-receiving sheet was evaluated based on the following evaluation criteria, and Table 1 summarizes the evaluation results.
(Evaluation criteria)
A: No adhesion of the thermal transfer image-receiving sheet to the SUS plate was observed, and the separated thermal transfer image-receiving sheet could be reattached.
NG: Adhesion of the thermal transfer image-receiving sheet to the SUS plate was observed, and the separated thermal transfer image-receiving sheet could not be reattached.

<<Conveyor roller contamination evaluation>>
Sublimation thermal transfer printer (Dai Nippon Printing Co., Ltd., DS40) and genuine thermal transfer sheet of the printer (Dai Nippon Printing Co., Ltd.) 10,000 prints on which a black solid image (0/255 gradation image) was formed was produced.
After the print was produced, the conveying roller (capstan roller) of the printer was visually checked and evaluated based on the following evaluation criteria. Table 1 summarizes the evaluation results.
(Evaluation criteria)
A: Adhesion of paper dust was hardly observed on the conveying roller.
B: Adhesion of paper dust was slightly observed on the conveying roller, but it was practically no problem.
NG: A lot of paper dust adhered to the conveying roller, and the conveyability of the thermal transfer image-receiving sheet was affected.

<<Conveyance Evaluation>>
Sublimation thermal transfer printer (Dai Nippon Printing Co., Ltd., DS40) and genuine thermal transfer sheet of the printer (Dai Nippon Printing Co., Ltd.) 50 printed matter on which a black solid image (0/255 gradation image) was formed was produced.
The produced prints were visually confirmed and evaluated based on the following evaluation criteria. Table 1 summarizes the evaluation results.
(Evaluation criteria)
A: No print misalignment occurred.
NG: Print misalignment occurred.

<<Anti-curl Evaluation>>
The thermal transfer image-receiving sheets obtained in the above Examples and Comparative Examples were cut into a size of 100 mm in width and 150 mm in length to prepare a test piece.
The test piece thus obtained was allowed to stand in an environment of 40° C. and relative humidity of 90% for 24 hours.
After standing, the test piece was placed on a flat table, and the lift heights at four corners were measured. Specifically, if the curl is concave on the receiving layer side, place it on a flat table with the receiving layer side facing up, and if the curling is convex on the receiving layer side, place the receiving layer side down. It was placed on a flat table and measured. The maximum floating height of the four corner points is the curl amount (positive value for convex curl toward the receiving layer side of the test piece, negative value for concave curl toward the receiving layer side of the test piece), and the following evaluation criteria are used. , the anti-curling property of the thermal transfer image-receiving sheet was evaluated. Table 1 summarizes the evaluation results together with the measured curl amounts.
(Evaluation criteria)
A: The absolute value of curl amount was less than 3 mm.
B: The absolute value of curl amount was 3 mm or more and less than 5 mm.
C: The absolute value of curl amount was 5 mm or more and less than 10 mm.
D: The absolute value of curl amount was 10 mm or more.

10: Thermal transfer image receiving sheet, 11: Receiving layer, 12: Paper substrate, 13: Core substrate, 14: Adhesive layer, 15: Release substrate, 16: Porous layer, 17: Release layer, 18: Primer layer

Claims (9)

A receiving layer, a paper substrate, a core substrate, an adhesive layer, a release layer, and a release substrate are provided in this order ,
The core substrate is a resin layer having a thickness of 5 μm or more,
The release substrate is composed of a resin film or a porous resin film,
A thermal transfer image-receiving sheet, wherein a laminate comprising the core substrate, the adhesive layer , the release layer and the release substrate has a breaking strength of 70 N or more and 200 N or less. 2. The thermal transfer image-receiving sheet according to claim 1, wherein the laminate has a breaking strength of 100N or more and 200N or less. 3. The thermal transfer image-receiving sheet according to claim 1, wherein the laminate has a breaking strength of 150N or more and 200N or less. The thermal transfer image-receiving sheet according to any one of claims 1 to 3, wherein the core substrate has a thickness of 10 µm or more and 45 µm or less. 5. The thermal transfer image-receiving sheet according to any one of claims 1 to 4, wherein the release base material has a thickness of 15 µm or more and 100 µm or less. The thermal transfer image-receiving sheet according to any one of claims 1 to 5, wherein the release base material is composed of a porous resin film. The thermal transfer image-receiving sheet according to any one of claims 1 to 6, comprising a porous layer between said receiving layer and said paper substrate. The thermal transfer image-receiving sheet according to any one of claims 1 to 7, wherein the release layer has a thickness of 0.1 µm or more and 2 µm or less. The thermal transfer image-receiving sheet according to any one of claims 1 to 8, wherein the release layer contains a silicone resin.

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