JP2002127617A - Heat transfer recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat transfer recording sheet of silver salt photographic taste, which is cured by radiation, permitting easily dyeing even in a low energy, permitting the obtaining of an image of high concentration and good in image preservability against sebaceous matter or oil. SOLUTION: The heat transfer recording sheet, obtained by curing a resin containing a urethane unsaturated organo oligomer represented by a general formula 1 through radiation, is provided with two kinds or more of different organic isocyanate residues in the formula while containing at least one kind of aromatic ring structure. (In the formula, -OR1O shows the dehydrogenation residue of polymer polyol having a number average molecular weight of 200-2,000, -R2- shows an organic di-isocyanate residue, -T3O- shows the dehydrogenation residue of hydroxyl group of dihydroxyl compound, CH2=C(R5). COOR4 O- is the dehydrogenation residue of a (metha) acrylic ester containing hydroxyl group containing one or more of double bound, R5 shows a hydrogen atom or a methyl group and -OR4O- shows the dehydrogenation residue of dihydric alcohol. Further, n shows an integer of 1-100).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer recording sheet for forming an image by transferring a dye by heat.
The present invention relates to a silver salt photographic-like thermal transfer recording sheet capable of obtaining a high-quality recorded image, having good sebum resistance, and having a high surface gloss.

[0002]

2. Description of the Related Art In recent years, various color image reproducing apparatuses such as a home video, a digital still camera, and computer graphics have become widespread, and accordingly, an apparatus for outputting reproduced image information as a color hard copy has been desired. As such an image output device, for example, an inkjet type, electrophotographic type, or thermal transfer type printer has been developed. Of these various printers,
As one means of color hard copy, there is a sublimation dye system in which a coloring material layer contains a sublimation dye. The characteristic color of the thermal transfer recording image of the sublimation dye system is that the reproduction of the color halftone is extremely beautiful due to the excellent polychromaticity and multi-gradation of the system.

[0003] Further, with the trend toward higher quality in recent years, there has been a tendency that superior gloss and gloss (shine) are desired even in hard copy, and thermal transfer having beautiful color and gloss like silver halide photographic printing paper. Recording sheets are being demanded in the market.

The printer principle of the sublimable dye transfer method is that an image is converted into an electric signal, and the electric signal is further converted into a heat signal by a thermal head (hereinafter, abbreviated as a head) to apply a sublimable dye to the sheet. (Ink sheet) is heated, and the sublimable dye is transferred and fixed on a thermal transfer recording sheet closely adhered to the ink sheet to reproduce an image. Conventional thermal transfer recording sheets are made of a support such as paper, synthetic paper, or a film filled with white pigment, and a thermoplastic resin such as polyester, polyamide, polycarbonate, vinyl acetate-vinyl chloride copolymer, acetate cellulose, or acrylic resin. It is provided with an image receiving layer as a main component.

When such a thermoplastic resin is used as an image receiving body and heat energy for obtaining a desired recording density is applied to the head, the image receiving body resin is softened or melted by the heat of the head and adheres to the ink sheet. In some cases, a phenomenon referred to as a so-called stick occurs in which the ink sheet and the image receiving body do not run at a specified speed. In order to solve such a phenomenon, a method of adding a crosslinking agent such as an organic polyfunctional isocyanate and thermally crosslinking the resin coating layer to improve heat resistance is used. However, this method using thermal crosslinking requires steps such as heating and requiring a large amount of energy, and / or so-called "sticking", which requires an operation for completing crosslinking. There was a problem above.

Accordingly, a method has been proposed in which a radiation-curable resin is used instead of such a thermoplastic resin requiring thermal crosslinking. As disclosure of such technology,
For example, JP-A-58-212994,
-23790, JP-A-63-74691,
JP-A-5-185746 is an example.

[0007] Among them, the technique disclosed in Japanese Patent Application Laid-Open No. 58-212994 uses a conventional thermoplastic resin and a radiation-curable radical polymerizable compound as a crosslinking agent, and is obtained by this technique. Image receivers do not always have sufficient sublimable dye receptivity. Further, Japanese Patent Application Laid-Open No. 63-74691 discloses a technique using a polyester resin having high dyeing properties as the above-mentioned thermoplastic resin. The image receiving body obtained by using this technique has a high transfer density, but is inferior in heat resistance, so that the inter-paper friction in a high-temperature environment deteriorates and a stick phenomenon occurs. When the inter-paper friction is deteriorated, a so-called double feed occurs in which several image receiving bodies are simultaneously fed during printing, which is not preferable.

Japanese Patent Application Laid-Open No. 23790/1987 discloses a technique in which a polyester urethane acrylate represented by the following general formula 2 and having a molecular weight of 3000 or less is used for a thermal transfer recording sheet.

[0009]

Embedded image

This urethane / unsaturated organo oligomer has a molecular weight of 3 having two hydroxyl groups in the molecule.
000 following polyester diol (constituting -OR ⁶ O-) and organic diisocyanate (-OCNHR ⁷ NHCO
-), A hydroxyl group-containing (meth) acrylic acid ester (R = RO-) is bonded to a urethane oligomer comprising However, the image receiver according to this technique has a disadvantage that the cured film is brittle due to the low molecular weight. If the cured film is brittle, the film is easily broken and the appearance of the image forming surface is significantly deteriorated, which causes a quality problem.

Furthermore, Japanese Patent Application Laid-Open No. 5-185746 describes that a radiation-curable organic compound having an isobornyl skeleton is used for a thermal transfer recording sheet.
The dye transfer density is not yet sufficient, and the breaking resistance is insufficient. The urethane / unsaturated organo oligomer according to the general formula 1 and a method for producing the same are disclosed in
Although it is disclosed in Japanese Patent No. 35657, there is no illustration or suggestion regarding the sublimation dye receptivity and the thermal transfer recording sheet.

[0012] In many cases, the image storability of the thermal transfer recording sheet using the radiation curable resin thus obtained is not always good. In particular, the image preservability for sebum greatly depends on the characteristics of the radiation-curable resin itself, so that it has been difficult to balance the quality until now.

As one means for solving this kind of problem, there is an over lamination method. This method, after transferring the sublimable dye of each color to the receiver and forming an image,
In this method, a type of overcoat layer is provided by transferring and bonding an overlaminated resin layer previously applied on an ink sheet to a receptor by the heat of a head. It is known that when this method is used, the overlaminate resin layer transferred onto the receptor prevents the penetration of sebum and oil, thereby improving the image preservability. However, in this method, since an over-laminated resin layer is provided on the ink sheet in addition to each color, an additional printing time is required, and the price of the ink sheet increases, so that the running cost tends to increase. And other issues.

[0014]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermal transfer recording sheet having excellent sublimation dye receptivity and good sebum resistance even without overlamination. . More specifically, a silver salt photographic tone thermal transfer recording sheet which is cured by radiation, can be easily dyed even at low energy, can obtain a high-density image, and has good image storability to sebum and oil. The task is to provide

[0015]

In order to solve the above-mentioned problems, a first aspect of the present invention employs the following configuration. That is, the present invention provides a thermal transfer recording sheet having a `` sheet-shaped support and a cured resin layer formed by applying a coating composition containing a radiation-curable resin on at least one surface thereof and radiation-curing the same, A thermal transfer recording sheet containing at least 10 parts by weight, based on the weight of the cured resin layer, of a urethane / unsaturated organo oligomer represented by the following general formula 1 as a radiation-curable resin in the coating composition, and Equation 1
Of the urethane / unsaturated organo oligomer of-
^2- is a thermal transfer recording sheet comprising two or more different organic diisocyanate residues, at least one of which contains an aromatic ring structure.

[0016]

Embedded image(Where -OR¹O- is a number average molecular weight of 200 to 2000.
Residue of a polymer polyol of the formula^Two− Is organic di
Isocyanate residue, -OR^ThreeO- is dihydroxyl
Indicates the dehydrogenated residue of the hydroxyl group of the compound, CH_Two=
C (R^Five) COOR ^FourO- is an amino group containing one or more double bonds.
Dehydrogenation of (meth) acrylic acid ester containing droxyl group
Residue^FiveIs a hydrogen atom or a methyl group, -OR^FourO
-Indicates a dehydrogenated residue of a dihydric alcohol, respectively. Also, n
Represents an integer of 1 to 100. )

In a second aspect of the present invention, in the first aspect, the organic diisocyanate residue -R ² -is 4,4-
A thermal transfer recording sheet comprising two kinds of diisocyanate residues of diphenylmethane diisocyanate and isophorone diisocyanate.

According to a third aspect of the present invention, in the first aspect,
When the organic diisocyanate residue -R ² -is 2,4- (2,
6) A thermal transfer recording sheet comprising two kinds of diisocyanate residues of tolylene diisocyanate and isophorone diisocyanate.

[0019]

DETAILED DESCRIPTION OF THE INVENTION One type of radiation-curable resin used in the present invention is a urethane / unsaturated organo oligomer represented by the above general formula 1. In the general formula 1, -OR ¹
O- dehydrogenation residue of a polymer polyol having a number average molecular weight 200 to 2000, -R ² - organic diisocyanate residue, -OR ³ O- shows a dehydrogenation residue of a hydroxyl group-containing dihydroxy compound, CH ₂ ＝ C (R ⁵ ) COOR
⁴ O- is a dehydrogenated residue of a hydroxyl group-containing (meth) acrylate ester having one or more double bonds, and R ⁵
Is a hydrogen atom or a methyl group, -OR ⁴ O-respectively indicate a dehydrogenation residue of a dihydric alcohol. N is 1 to 100
Indicates an integer.

There is no particular limitation on the polymer polyol which is the raw material of —OR ¹ O—. Examples of the polymer polyol include the following polymer diols. For example, at least one kind of polyether diol selected from polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like, at least one kind of polycarbonate diol selected from hexamethylene carbonate and pentamethylene carbonate, polycaprolactone diol and polybutyrolactone At least one kind of polylactone diol selected from diols.

As an example of the polymer polyol, a polyester polyol can be mentioned. The polyester polyol is a hydroxyl group-containing polyester (especially a polyester diol) obtained by reacting a polyhydric alcohol with a polycarboxylic acid or a lower alkyl ester or an acid anhydride thereof, and a polyester derived from a lactone. Good. The polyol components can be used alone or in combination of two or more. As the polyol component, a diol component (for example, polyester diol or the like) is often used.

The polyhydric alcohol for preparing the polyester polyol includes, for example, aliphatic polyhydric alcohols (eg, ethylene glycol, trimethylene glycol, propylene glycol, 1,3-butanediol,
C2-C10 alkylene diols such as tetramethylene glycol, hexamethylene glycol, neopentyl glycol, or diethylene glycol;
Triethylene glycol, polyoxyalkylene glycol such as polyoxytetramethylene glycol {alkylene group having 2 to 10 carbon atoms, trimethylolpropane,
Polyols such as pentaerythritol), alicyclic polyhydric alcohols (for example, alicyclic diols such as 1,4-cyclohexane dimethylol and hydrogenated bisphenol A), aromatic polyhydric alcohols (for example, 2,2- And aromatic diols such as bis (2-hydroxyethylphenyl) propane. Polyhydric alcohols can be used alone or in combination of two or more. The polyhydric alcohol is usually an aliphatic diol.

Examples of the polycarboxylic acid include aliphatic polycarboxylic acids (for example, unsaturated aliphatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid and dodecanedicarboxylic acid, and unsaturated acids such as maleic acid). Aliphatic dicarboxylic acid, etc.), alicyclic polycarboxylic acid (e.g., alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid), aromatic polycarboxylic acid (e.g.,
Examples thereof include aromatic dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, and 1,5-naphthalenedicarboxylic acid, and aromatic polycarboxylic acids such as trimellitic acid. Polycarboxylic acids can be used alone or in combination of two or more. Lactones include, for example, butyrolactone, valerolactone, caprolactone, and the like,
You may use individually or in combination of 2 or more types.

One of these polyether-based diols, polycarbonate-based diols, polylactone-based diols, and polyester polyols can be selected from one type or a combination of two or more types. The number average molecular weight of the polymer polyol is from 200 to 2,000, more preferably from 300 to 1500.

In the present specification, -R ^2- is expressed as a diisocyanate residue for the sake of convenience, but is exactly a divalent organic group derived from an organic diisocyanate compound. For example, any of a divalent aromatic group, an aliphatic group, a cycloaliphatic group, and a heterocyclic group, for example, an alkylene group with or without a substituent, a cycloalkylene group, a phenylene group, a diphenylene Group, a diphenylmethane group, an isophorone group, a methylene (4-cyclohexyl) group, a naphthalene group, or a norgylnan group. The organic diisocyanate compound derived from —R ² — is 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylene bis (4-cyclohexyl isocyanate), Tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, cyclohexane-1,3
Dimethylene diisocyanate, cyclohexane-1,
At least two or more types selected from 4-dimethylene diisocyanate, norbornane diisocyanate, 1,5-naphthalenediisocyanate, and the like are preferable, and at least one type is an organic diisocyanate compound having an aromatic ring structure. Specific examples of the organic diisocyanate compound having an aromatic ring structure include 2,2.
4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4-diphenylmethane diisocyanate, xylylene diisocyanate, 1,5-naphthalenedi isocyanate and the like.

The compounding ratio of the organic diisocyanate having an aromatic ring structure is 5 to the total amount of the organic diisocyanate.
It is good that it is not less than 90 parts by weight, preferably not less than 10 parts by weight and not more than 90 parts by weight. If the amount of the organic diisocyanate having an aromatic ring is less than 5 parts by weight based on the total amount of the organic diisocyanate, the effect of improving sebum resistance is not sufficient, and if it exceeds 90 parts by weight, the viscosity of the entire coating material is significantly increased. It is not preferable because the image storability other than sebum resistance such as light resistance is significantly impaired.

Above all, when isophorone diisocyanate and 4,4-diphenylmethane diisocyanate are used as organic diisocyanate compounds, or
When isophorone diisocyanate and 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate are used, the increase in paint viscosity is suppressed without reducing the effect of the present invention by the claimed material, and / or It is preferable because other image storability such as light resistance is not impaired.

The dihydroxyl compound which is the raw material of —OR ³ O— is preferably at least one selected from glycols having 2 to 10 carbon atoms. Therefore, -R ³ in the general formula 1 - refers to a hydrocarbon having 2 to 10 carbon atoms. More preferably, it has 2 to 6 carbon atoms, specifically, ethylene glycol, 1,3-propanediol, 1,4-
Butanediol, neopentyl glycol, 1,5-pentanediol, methylpentanediol, 1,6-hexanediol, and 3-methyl-1,5-pentanediol. − (OR ¹ OOCHR ² NHCOOR
³ OOCNHR ² NHCO) n- in, in parentheses, in repeating units of urethane unsaturated organosiloxane oligomer, n
Is an integer of 1 to 100, preferably 1 to 20, more preferably 1 to 10.

The raw material of the CH ₂ ＣC (R ⁵ ) COOR ⁴ O— (meth) acrylate structure containing at least one double bond constituting both ends of the urethane / unsaturated organo oligomer is a hydroxyl group-containing material. (Meth) acrylic acid ester, specifically, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, hydroxybutyl (meth) Acrylate, caprolactone or alkylene oxide adduct of each acrylate, glycerin mono (meth) acrylate, glycerin di (meth) acrylate, glycidyl methacrylate-acrylic acid adduct, trimethylolpropane mono (meth) acrylate, trimethylol di (meth) Acrylate , Pentaerythritol tri (meta)
Acrylate, dipentaerythritol penta (meth)
Acrylate, ditrimethylolpropane tri (meth)
At least one selected from acrylate, trimethylolpropane-alkylene oxide adduct-di (meth) acrylate and the like can be applied. R ⁵ -represents a methyl group or a hydrogen atom.

In order to obtain the urethane / unsaturated organo oligomer represented by the above formula 1, first, the number average molecular weight is 200
2,000 polymer diols are subjected to a polyaddition reaction with a dihydroxyl group compound and an organic isocyanate compound to obtain a urethane oligomer having isocyanate groups at both ends. Then, a hydroxyl group-containing (meth) acrylic acid ester is added and condensed to the terminal isocyanate group for synthesis. In the synthesis, a part of dihydroxy alcohol, which is a raw material of —OR ¹ O—, may be replaced with a polymer polyol, which is a raw material of —OR ³ O—. That is, in the general formula 1, a part of R ¹ may be changed to R ³ .

The urethane / unsaturated organo-oligomer thus obtained is irradiated with one or more types of radiation selected from electron beams and ultraviolet rays to form one or more double bonds constituting both terminals. The contained (meth) acrylate structure part CH ₂ ＣC (R ⁵ ) COOR ⁴ O— polymerizes to form the intended radiation-curable resin coating layer according to the present invention. In the case of curing polymerization by irradiation with ultraviolet rays, it is preferable to use a compound called a photoreaction initiator which generates radical species, cation species, anion species and the like by light irradiation.

Next, components other than the general formula 1 in the coating composition will be described. The coating composition may contain other components in order to control the sublimation dye receptivity, friction, whiteness, coating fluidity, curing speed, and the like. However, the substance represented by the general formula 1 is 1 to the weight of the cured resin coating layer.
It is necessary to be 0% or more, preferably 20% or more. Here, the weight of the cured resin layer means the weight after drying the water / solvent, etc., ending the curing reaction, and removing volatile components. Examples of the other components include a radiation curable compound, an organic solvent, and a pigment. Further, various additives such as antioxidants, antistatic agents, stabilizers, lubricants such as silicone oil and friction coefficient reducing agents, and furthermore, light resistance improvers and the like can be appropriately added.

Examples of the organic solvent used for lowering the viscosity of the paint and facilitating the coating include 2-butanone, acetone and toluene. As the radiation-curable organic compound, monomers, oligomers and polymers conventionally known for radiation-curable thermal transfer recording receptors can be used.

Specific examples thereof include, for example, monofunctional compounds such as methyl acrylate, ethyl acrylate, lauryl acrylate, stearyl acrylate, N-vinylpyrrolidone, acryloyl morpholine,
2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate , Caprolactone-modified tetrahydrofurfuryl acrylate, cyclohexyl acrylate, cyclohexyl methacrylate, dicyclohexyl acrylate, isobornyl acrylate, isobornyl methacrylate, benzyl acrylate, benzyl methacrylate, ethoxydiethylene glycol acrylate, methoxytriethylene glycol acrylate,
Methoxypropylene glycol acrylate, phenoxy polyethylene glycol acrylate, phenoxy polypropylene glycol acrylate, nonylphenoxy polyethylene glycol acrylate, ethylene oxide-modified phenoxy acrylate, nonylphenoxy polypropylene glycol acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, 2-ethylhexyl carbitol acrylate, ω-carboxypolycaprolactone monoacrylate, monohydroxyethyl phthalate, acrylic acid dimer, 2-hydroxy-3-phenoxypropyl acrylate, acrylic acid-9,10
Epoxidized oleyl, methacrylic acid-9,10-epoxidized oleyl, ethylene glycol monoacrylate maleate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethylene acrylate, 4,4-dimethyl-1,3 Acrylates of caprolactone adducts of dioxolane, 3
-Methyl-5,5-dimethyl-1,3-dioxolane adduct of caprolactone, polybutadiene acrylate, ethylene oxide-modified phenoxylated phosphoric acid acrylate, and the like.

Further, as the polyfunctional compound, ethanediol diacrylate, ethanediol dimethacrylate,
1,3-propanediol diacrylate, 1,3-propanediol dimethacrylate, 1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol diacrylate,
1,6-hexanediol dimethacrylate, 1,9-
Nonanediol diacrylate, 1,9-nonanediol dimethacrylate, 1,14-tetradecanediol diacrylate, 1,15-pentadecanediol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, polypropylene glycol diacrylate , Polypropylene glycol dimethacrylate, neopentyl glycol diacrylate, 2-
Butyl-2-ethylpropanediol diacrylate,
Ethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified bisphenol A diacrylate, polyethylene oxide modified hydrogenated bisphenol A diacrylate, propyl oxide modified bisphenol A diacrylate, polypropylene oxide modified bisphenol A diacrylate, hydroxypivalic acid ester neopentyl glycol ester diacrylate Acrylate, hydroxypivalic acid ester neopentyl glycol ester caprolactone adduct diacrylate,
Ethylene oxide-modified isocyanuric acid diacrylate,
Pentaerythritol diacrylate monostearate, 1,6-hexanediol diglycidyl ether acrylic acid adduct, polyoxyethylene epichlorohydrin-modified bisphenol A diacrylate, tricyclodecane dimethanol diacrylate, trimethylolpropane triacrylate, ethylene oxide Modified trimethylolpropane triacrylate, polyethylene oxide-modified trimethylolpropane triacrylate, propylene oxide-modified trimethylolpropane triacrylate, polypropylene oxide-modified trimethylolpropane triacrylate, pentaerythritol triacrylate, ethylene oxide-modified isocyanuric acid triacrylate, ethylene oxide-modified glycerol triacrylate Acrylate, poly Tylene oxide-modified glycerol triacrylate, propylene oxide-modified glycerol triacrylate, polypropylene oxide-modified glycerol triacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, Examples include caprolactone-modified dipentaerythritol hexaacrylate and polycaprolactone-modified dipentaerythritol hexaacrylate. However, it is not limited to these.

Of these, the use of the following radiation-curable compounds makes it possible to reduce the viscosity of the coating without reducing the effect of the substance of the general formula 1. For example, ethylene glycol diacrylate, 1,2-propanediol diacrylate, 1,3
-Propanediol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate,
Examples thereof include 1,5-pentanediol diacrylate, methylpentanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, and 2-ethyl, 2-butyl-propanediol diacrylate.

When a pigment is incorporated into the coating composition, the pigment is preferably less than 80 parts by weight based on the total weight of the cured resin layer after drying. More preferably, it is less than 60 parts by weight. When the amount exceeds 80 parts by weight, not only does the effect of the present invention decrease, but also the viscosity of the resin coating before curing becomes excessively high, which may result in poor fluidity.
Examples of the pigment include clay, kaolin, talc, silica, magnesium hydroxide, aluminum hydroxide, heavy calcium carbonate, light calcium carbonate, titanium dioxide (anatase type and rutile type), zinc white, and barium sulfate. Organic pigments such as polystyrene, known as plastic pigments, can be used.

These pigments are usually white and may be used without any surface treatment. Alternatively, pigments which have been surface-treated with siloxane, alumina, alcohol, a silane coupling agent or the like may be used. The pigment may be composed of a single type, or may be used as a mixture of two or more types. In addition, the radiation-curable resin composition containing such a pigment includes a dispersant, a release agent, an antifoaming agent, a colorant, a dye,
Known auxiliaries, such as preservatives, can be added as needed. To disperse the white pigment in the radiation-curable resin composition, a three-roll mill (three-roll mill), a two-roll mill (two-roll mill), a Cowles dissolver,
A homomixer, a sand grinder, a planetary mixer, an ultrasonic disperser and the like can be used.

In the method for producing a thermal transfer recording sheet according to the present invention, a radiation-curable resin composition is applied on the surface of a sheet-like support to form a coating liquid layer, which is cured by irradiation with radiation. Good. If the coating liquid contains an organic solvent such as toluene, acetone, or 2-butanone, a drying step may be provided. The drying device used is not particularly limited, and an electric or gas infrared dryer using radiant heat, a roll heater using electromagnetic induction, an oil heater using an oil medium, and a drying device using these hot airs And the like.

Furthermore, in order to impart gloss, it is possible to use a casting method. As the casting method, (1) a radiation-curable coating composition is applied on the surface of a sheet-like support to form a coating liquid layer, and the coating liquid layer is brought into contact with the surface of the molding substrate in a state of radiation curing. (2) A radiation curable coating composition is applied to the surface of the molded substrate to form a coating liquid layer, and a sheet-like support is attached to the coating liquid layer. There is a method of separating the sheet containing the cured resin layer from the surface of the molded body by radiation curing, but any one of these methods or another method may be used.

Examples of the method of applying the radiation-curable coating composition to a support include a bar coating method, an air doctor coating method, a blade coating method, a squeeze coating method, an air knife coating method, a roll coating method, and a gravure coating method. , Transfer coating method, comma coating method, smoothing coating method, microgravure coating method, reverse roll coating method, multi-roll coating method, dip coating method, rod coating method, kiss coating method, gate roll coating method, falling curtain coating method, Slide coating method,
A fountain coating method, a slit die coating method, or the like can be used. In particular, when a metal cylindrical rotating body is used as a molding base by a casting method, a roll coating method using a coating rubber roll or an offset gravure coating is used to prevent the surface of the metal cylindrical rotating body from being damaged. It is preferable to use a non-contact type fountain coater, a slit die coater or the like.

As a molding substrate used in the casting method, a metal cylindrical rotating body can be used, but there is no limitation on the material shape thereof. For example, stainless steel, copper,
What is formed from chrome or the like and has a mirror-finished smooth peripheral surface is used. Further, in order to facilitate the separation between the cured resin coating layer and the surface of the substrate, a release aid such as silicone oil or wax can be supplied to the surface of the metal cylindrical rotary member. The molding sheet material used as the molding substrate is not particularly limited as long as it is smooth and flexible, but specifically, a plastic film such as a polyester film, a metal sheet, a resin-coated paper, a metal-deposited film, Metal-deposited paper or the like is preferable, and a release aid such as silicone or wax may be supplied to the surface of the sheet material for molding in order to facilitate release of the cured resin coating layer. Further, the surface of the sheet-shaped material may be subjected to an appropriate treatment in advance, for example, a treatment such as a silicone treatment, to facilitate the peeling of the cured resin coating layer. The sheet-like material used as the molding base may be processed into an endless belt shape. The sheet-like material used as the molding base can be used repeatedly, but the repeated irradiation will deteriorate the sheet-like material, and thus the number of times of repeated use is limited.

Further, a precoat layer may be used for the purpose of averaging unevenness of the support of the present invention and improving whiteness and opacity, and the same purpose and / or surface smoothness is further enhanced. For the purpose, the radiation curable resin coating layer may have a laminated structure of two or more layers. Providing such a precoat layer is a means generally used in the field of coating a radiation-curable resin composition on a sheet-like support to form a resin coating layer, for example, a radiation-curable resin composition. It is used in the production of photographic printing paper supports, electrophotographic transfer papers, heat-sensitive base papers, process release papers, ink jet recording papers, wrapping papers, etc. coated with objects.

First, a normal precoat layer will be described. Inorganic coat layers such as clay, talc, kaolin, ansilex, etc.
Polyethylene (high density polyethylene, low density polyethylene, medium density polyethylene, linear low density polyethylene),
Thermoplastic resin homopolymer such as polypropylene, polybutene, polypentene, or copolymer of two or more olefins such as ethylene / propylene copolymer, (meth) acrylic resin, vinyl resin, cellulose resin, urethane Organic materials such as resins, polyester resins, and copolymer resins thereof can be used, and these resins can be used alone or in combination.
These resins may contain a white pigment for improving whiteness and opacity. Further, hollow particles may be contained for the purpose of improving the adhesion to the ink sheet and the heat insulating property of the image receiving layer. These inorganic and / or organic materials are applied by being dissolved or dispersed in a solvent or aqueous medium.

Next, the case where the precoat layer is also a radiation-curable type, that is, the case where two or more radiation-curable resin layers are provided, will be described. In this case, the components in the coating composition and the coating method can be considered in the same manner as in the case of the first layer, but it is reasonable to change the roles of the first layer and the second layer as necessary. For example, the inner resin coating layer is formed from a radiation-cured cured product of a radiation-curable resin composition containing a pigment, improves whiteness and opacity, and the outermost resin coating layer contains a pigment. It is formed from a cured product of a radiation-curable resin composition that is not irradiated by radiation and imparts surface smoothness. Furthermore, in order to impart surface smoothness and glossiness, it is also possible to use a casting method for forming them.

When two or more radiation-coated image-receiving layers are formed, the first layer of the radiation-curable resin composition is applied to form an inner coating liquid layer, and the second layer is separately formed on the surface of the molded substrate. The radiation curable resin composition is applied to form an outermost coating liquid layer, and the surface of the molding substrate is cured by irradiating radiation on the surface of the molding substrate to form an outermost coating liquid layer. The inner coating liquid layer on the sheet-like support is superimposed on the uppermost outermost resin coating layer, and irradiation is performed on the formed multilayer body, so that the inner coating liquid layer and the outermost resin coating layer are exchanged. A method of bonding and curing the sheet-like support and the outermost resin coating layer via the inner resin coating layer to form a multi-layer body, and peeling this laminate from the surface of the molded substrate. It can also be applied to the invention.

In the thermal transfer recording sheet of the present invention, the coating amount of the radiation-curable resin layer (the coating amount in the case of one layer and the total coating amount in the case of two or more layers) is 2 to 2 after curing.
It is preferably 60 g / m ² , more preferably 3 g / m ^2.
４０40 g / m ² . If the coating amount is less than 2 g / m ² , the resulting coated body will have insufficient smoothness, fail to provide aesthetics, and may have a reduced gloss. If it exceeds 60 g / m ² , the effect may be saturated and the cost may increase. Further, the transfer density of the sublimable dye may decrease, which is not preferable.

When two or more layers are coated, the coating amount after curing is preferably 0.1 g / m ² or more in order to impart beauty by the outermost resin coating layer. And more preferably 0.3 to 20 g / m ² . When the coating amount of the outermost resin coating layer is less than 0.1 g / m ² , the concealing property may be insufficient even if the blending amount of the pigment is large. In order to ensure the function of the inner resin coating layer, the coating amount after curing is preferably ² g / m ² or more, more preferably 5 to 20 g / m ² . If the coating amount of the inner resin coating layer is less than 3 g / m ² , formation unevenness of the paper substrate cannot be filled, and the resulting thermal transfer recording sheet may have insufficient surface smoothness.

There is no particular limitation on the type of sheet-like support used in the present invention, and paper (for example, high-quality paper, coated paper, laminated paper), glass paper, plastic film, and so-called synthetic paper obtained by converting plastic film into pseudo paper are used. A relatively thin material such as paper, cloth, synthetic fiber, nonwoven fabric, or aluminum foil can be used. As the paper substrate, a paper substrate having a weight of usually 50 to 300 g / m ² and a smooth surface is used. The type of paper substrate used in the present invention is not particularly limited. As the pulp forming the paper substrate, generally, natural pulp such as softwood pulp manufactured from fir tree, toga, etc., hardwood pulp manufactured from maple, beech, poplar, etc., and softwood mixed pulp mixed with pulp is mainly used. Is widely used, and bleached pulp such as kraft pulp, sulfite pulp and soda pulp can be used. Further, paper bases manufactured from pulp including synthetic fibers and synthetic pulp can also be used. For the paper substrate, various usual additives,
For example, one or more of a dry paper strength enhancer, a sizing agent, a filler, a wet paper strength enhancer, a fixing agent, a pH adjuster and the like can be contained.

Further, the sheet-like support of the present invention may be made of, for example, clay or paper on one or both sides of a paper substrate such as high quality paper.
Pigments such as talc, kaolin, calcium carbonate, aluminum hydroxide, titanium dioxide, magnesium hydroxide, plastic pigment, acrylic resin, polyurethane resin, ethylene-acrylic acid copolymer resin, vinyl acetate-ethylene copolymer resin, styrene -Coated paper, cast-coated paper having a pigment coating layer mainly composed of a synthetic resin such as butadiene copolymer resin and vinylidene chloride resin,
Pigment coated paper such as art paper, laminated paper having one or both sides laminated with a polyolefin resin such as polyethylene may be used, and when a paper substrate is used, the penetration of the radiation-curable resin composition may be reduced. To prevent this, a precoat layer may be separately provided with a barrier agent such as polyvinyl alcohol, hydroxyethyl cellulose, oxidized starch and the like. When a sheet-like support having such a coating layer is used, the inner radiation-curable resin coating layer as the precoat layer may not be used, and the outermost radiation resin may be directly provided on the resin coating layer of the sheet-like support. A coating layer may be formed.

Further, a plastic film or a sheet-like support such as so-called synthetic paper may be used in place of the paper substrate used in the present invention. For example, a film formed by melting and extruding a thermoplastic resin composition containing a polyolefin resin such as a polypropylene resin or a polyethylene resin can be used as the sheet-like support. Synthetic paper obtained by processing these films into pseudo paper can also be used as a sheet-like support. The plastic film or synthetic paper used as the sheet-like support may be a laminate of a plurality of different and / or the same types of films, and may further include clay, talc, kaolin, calcium carbonate, titanium dioxide, One or more kinds of pigments such as magnesium hydroxide, dispersants such as metal soaps such as zinc stearate and various surfactants, and colored pigments may be contained.

In the present invention, the surface of the support may be subjected to a surface treatment such as corona treatment or sub-coating in order to improve the adhesion and wettability between the support and the resin coating layer. On the back surface of the thermal transfer recording sheet of the present invention, a resin coating layer is formed by a method of applying a polyolefin resin by a melt extrusion method or a method of applying a radiation-curable resin and then forming a film by irradiating radiation, and preventing curling. A back coat layer can be provided for antistatic properties and for imparting writability. The back coat layer may contain an antistatic agent, a hydrophilic binder, a latex, a hardener, a pigment, a surfactant and the like in an appropriate combination.

The radiation for curing the radiation-curable resin paint according to the present invention may be, for example, one or more high-energy rays selected from electron beams, ultraviolet rays and the like. The electron beam irradiation device used for the electron beam irradiation is not particularly limited, and for example, an electron beam irradiation device such as a handy-graft scanning method, a double scanning method, a broad beam method, and a curtain beam method is used. Can be. Among them, the curtain beam method, which is relatively inexpensive and provides a large output, is effectively used in the present invention.

The accelerating voltage at the time of electron beam irradiation is preferably 100 to 1000 kV from the viewpoints of transmission power and curing power, and more preferably, an electron beam accelerator of 100 to 300 kV is used. It is preferable to make it 1 to 20 Mrad. Furthermore, 0.5 to 10 Mrad
Is particularly preferred. If the accelerating voltage or the amount of electron beam irradiation is lower than this range, the penetrating power of the electron beam is too low to sufficiently cure the inside of the support, and if it is higher than this range, not only does energy efficiency deteriorate. In addition, unfavorable effects on quality such as a decrease in the strength of the support and decomposition of the resin and additives appear. In addition, at the time of electron beam irradiation, if the oxygen concentration is high, the curing of the electron beam curable resin is prevented,
Substitution with an inert gas such as nitrogen, helium, carbon dioxide or the like is performed to reduce the oxygen concentration to 1000 ppm or less, preferably 5 ppm or less.
It is preferable that the irradiation be performed in an atmosphere in which the concentration is suppressed to 00 ppm or less.

In the case of ultraviolet rays, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, or the like can be used as an ultraviolet irradiation device. Further, an ozone-less type that generates less ozone may be used. It is desirable to use a lamp having an energy of 80 W / cm or more for the irradiation. Further, a photo-reaction initiator can be mixed and used in the radiation-curable resin paint. Examples of photoinitiators include acetophenones such as di and trichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyldimethyl ketal, tetramethylthiuram monosulfide,
Thioxanthones, azo compounds and the like.

[0056]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The number of parts by weight is part by weight. Example 1 A thermal transfer recording sheet having a single layer of a radiation-curable resin coating layer was prepared and evaluated by the following operation.

[0057] The composition (1) urethane unsaturated organosiloxane oligomer according to Ingredient amount present invention (Trademark: UF73502LE, Kyoeisha Chemical Co., Ltd.) 35 parts of neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts of 2-butanone 50 parts Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 parts Details of the urethane / unsaturated organo oligomer according to the present invention in the composition (1) are described in Table 1 (including footnotes, the same applies hereinafter). This is disclosed in Japanese Patent Application Laid-Open No. 11-356.
No. 57 was synthesized according to the method described therein.

Preparation of Thermal Transfer Recording Sheet The above composition (1) was prepared using synthetic paper (manufactured by Oji Yuka Synthetic Paper Co., Ltd., thickness 110 μm) as a base sheet. Coating with a wire bar so that the coating amount after drying and curing is 10 g / m ² ,
For 1 minute. The accelerating voltage is 175
The composition (1) was cured by irradiating an electron beam under the conditions of kV, an absorbed dose of 7 Mrad, and an oxygen concentration of 500 ppm or less to obtain a thermal transfer recording sheet of the present invention.

Test and Evaluation Method (1) Evaluation of Dye Transfer Density The dye transfer density was measured using a commercially available color video printer (SON).
(Y: UP-5500), and the reflection density at step 14 was evaluated with a Macbeth densitometer (RD-914, manufactured by Sakata Inx Corporation, using an A filter).

(2) Evaluation of sebum resistance In the same manner as in (1), step printing was performed, and the sample receiving paper whose reflection density was measured in advance was placed in an atmosphere of 35 ° C., and oleic acid, one of the oil acids of the sebum component, was placed. Was dropped at the gradation of Step 9 and left standing for 10 minutes. Thereafter, the oleic acid adhering to the sample was sufficiently wiped off with a soft paper, and the reflection density value was measured in the same manner as in (1). The rate of change of the reflection density value before and after the test was calculated and evaluated as sebum resistance.

(3) Evaluation of light fastness A sample receiving paper on which step printing was performed in the same manner as in (1) and the reflection density was measured in advance was applied to an Atlas light fastness tester (manufactured by Toyo Seiki Seisakusho) at 40 ° C. and 50% RH. For 72 hours under a xenon lamp (using a soda lime filter). Thereafter, the reflection density value was measured in the same manner as in (1). The rate of change of the reflection density value in Step 9 before and after the test was calculated and evaluated. Table 2 shows the evaluation results.

<Example 2> The same operation as in Example 1 was performed. However, instead of the composition (1), the following composition (2)
Was prepared and used. Composition (2) Urethane-unsaturated organosiloxane oligomer according to Ingredient amount present invention (Trademark: UF77502LE, Kyoeisha Chemical Co., Ltd.) 35 parts of neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts 2-butanone 50 parts Silicone Oil (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 part Details of the urethane / unsaturated organo oligomer according to the present invention in the composition (2) are described in Table 1. Also,
This was synthesized according to the method described in JP-A-11-35657. Further, a thermal transfer recording sheet was prepared and evaluated in the same manner as in Example 1. Table 2 shows the evaluation results.

Example 3 A thermal transfer recording sheet having a single radiation-curable resin coating layer was prepared by the following procedure. However, instead of the composition (1), the following composition (3)
Was prepared and used. Composition (3) Urethane unsaturated organosiloxane oligomer according to Ingredient amount present invention (Trademark: UF73502LE, manufactured by Kyoeisha Chemical Co., Ltd.) 35 parts of neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts 2-butanone 50 parts Composition Details of the urethane / unsaturated organo oligomer according to the present invention in the product (3) are described in Table 1. Also,
This was synthesized according to the method described in JP-A-11-35657.

Preparation of Thermal Transfer Recording Sheet The above composition (3) was prepared by using a synthetic paper (manufactured by Oji Yuka Synthetic Paper Co., Ltd., thickness: 110 μm) as a base sheet, and applying a coating liquid on one surface of the synthetic paper (# 10). Coating with a wire bar so that the coating amount after drying and curing is 10 g / m ² ,
For 1 minute. After overlaying a 75 μm silicone-coated polyester film (trademark: SP-PET-O5-75B, manufactured by TOCELLO) used as a molding base thereon, the multilayer body was accelerated from the back of the silicone-coated polyester film. The composition (3) was cured by irradiating an electron beam under the conditions of a voltage of 175 kV, an absorbed dose of 7 Mrad, and an oxygen concentration of 500 ppm or less. Thereafter, the polyester film was peeled off from the resin coating layer to obtain a thermal transfer recording sheet of the present invention having a radiation-curable resin coating layer.
Further, a thermal transfer recording sheet was prepared and evaluated in the same manner as in Example 1. Table 2 shows the evaluation results.

Example 4 A thermal transfer recording sheet was prepared by the following operation. Composition (4) (outermost resin coating layer formation) urethane unsaturated organosiloxane oligomer according to Ingredient amount present invention (Trademark: UF73502LE, Kyoeisha Chemical Co., Ltd.) 70 parts of neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd. ) 30 parts of composition (5) (for the inner resin coating layer formed) Ingredient weight urethane-unsaturated organosiloxane oligomer (trademark: UF502LE, Kyoeisha chemical Co., Ltd.) 35 parts 2-butanone 35 parts of titanium dioxide (trademark: R- 23, manufactured by Sakai Chemical Co., Ltd.) 30 parts Details of the urethane / unsaturated organo oligomer in the compositions (4) and (5) are described in Table 1. Also,
These were synthesized according to the method described in JP-A-11-35657.

Preparation of Thermal Transfer Recording Sheet The composition (5) was applied to synthetic paper (thickness: 1) as a base sheet.
10 μm) One surface was coated with a # 10 wire bar so that the coating amount after curing was 10 g / m ^2.
After drying at 0 ° C for 1 minute, the applied voltage is 175 kV
The composition (5) was cured by irradiation with an electron beam under the conditions of an absorbed dose of 7 Mrad and an oxygen concentration of 500 ppm or less to form an inner resin coating layer. Next, the composition (4) was coated on the formed inner resin coating layer with a # 10 wire bar so that the coated amount after curing was 5 g / m ² , and molded from above. After overlaying a 75 μm silicone-coated polyester film used as a substrate, an accelerating voltage of 1 was applied to the multilayer body from the back of the silicone-coated polyester film.
The composition (4) is cured by irradiating an electron beam under the conditions of 75 kV, an absorbed dose of 7 Mrad, and an oxygen concentration of 500 ppm or less.
The inner resin coating layer, the outermost resin coating layer, and the support were integrally bonded. Thereafter, the silicone-coated polyester film was peeled off from the resin coating layer to obtain a thermal transfer recording sheet having a radiation-curable resin coating layer. The thermal transfer recording sheet was evaluated in the same manner as in Example 1. Table 2 shows the evaluation results.

<Comparative Example 1> Referring to the examples described in JP-A-62-2790, the following composition (6) was prepared in place of composition (1). The operation was performed. Composition (6) Component Compounding amount Urethane / unsaturated organo oligomer of polycaprolactone diol (manufactured by Kyoeisha Chemical Co., Ltd.) 35 parts Neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts 2-butanone 50 parts Silicone oil (Shin-Etsu Chemical (Industrial product) 0.3 part A thermal transfer recording sheet was prepared and evaluated in the same manner as in Example 1. Table 2 shows the evaluation results. Table 1 shows details of the urethane / unsaturated organo oligomer according to the composition (6).

Comparative Example 2 The following operation was carried out in the same manner as in Example 1 except that the following composition (7) was prepared in place of the composition (1). Composition (7) Component Compounding amount Urethane / unsaturated organo oligomer having a single organic diisocyanate structure (trade name: UF502LE, manufactured by Kyoeisha Chemical Co., Ltd.) 35 parts Neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts 2- Butanone 50 parts Silicone oil (Shin-Etsu Chemical Co., Ltd.) 0.3 parts A thermal transfer recording sheet was prepared and evaluated in the same manner as in Example 1. Table 2 shows the evaluation results. Table 1 shows details of the urethane / unsaturated organo oligomer according to the composition (7).

Comparative Example 3 The following composition (8) was prepared in place of the composition (1), and the same operation as in Example 1 was performed. Composition (8) Component Compounding amount Urethane / unsaturated organo oligomer having a single organic diisocyanate structure (trade name: UF7502LE, manufactured by Kyoeisha Chemical Co., Ltd.) 35 parts Neopentyl glycol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 15 parts 2- Butanone 50 parts Silicone oil (Shin-Etsu Chemical Co., Ltd.) 0.3 parts A thermal transfer recording sheet was prepared and evaluated in the same manner as in Example 1. Table 2 shows the evaluation results. Table 1 shows details of the urethane / unsaturated organo oligomer according to the composition (8).

<Comparative Example 4> Referring to the examples described in JP-A-63-74691, the following composition (9) was prepared in place of composition (1), and thermal transfer recording was performed by the following operation. A sheet was prepared. Composition (9) Component Compounding amount Polyester resin (manufactured by Toyobo Co., Ltd .: RV200) 100 parts Pentaerythritol acrylate (manufactured by Nippon Kayaku Co., Ltd.) 20 parts 2,2-bis (4-acryloyloxydiethoxyphenyl) propane (Arakawa Chemical 20 parts Silicon oil (manufactured by Toray Dow Corning: SF8724) 3 parts Toluene / 2-butanone = 11/1 mixed solvent 584 parts

Preparation of Thermal Transfer Recording Sheet The above composition (9) was used as a base sheet in synthetic paper (thickness: 1).
10 μm), and the coating liquid was applied on one side of the wire bar to a # 10 wire bar so that the coating amount after curing was 10 g / m ^2, and dried at 100 ° C. for 1 minute. From this aspect, the accelerating voltage is 175 kV, the absorbed dose is 7 Mrad, and the oxygen concentration is 500.
The composition (9) was cured by irradiating an electron beam under the condition of ppm or less to obtain a thermal transfer recording sheet. Evaluation was performed in the same manner as in Example 1. Table 2 shows the evaluation results.

Comparative Example 5 The following composition (10) was prepared in place of the composition (1) according to the examples described in JP-A-5-185746, and a thermal transfer recording sheet was prepared by the following operation. Produced.

[0073] The composition (10) Ingredient weight isobornyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd.) 60 parts of trimethylolpropane triacrylate (manufactured by Toagosei Chemical Industry Co., Ltd.) 40 parts

Preparation of Thermal Transfer Recording Sheet The above composition (10) was prepared by using a synthetic paper (manufactured by Oji Yuka Synthetic Paper Co., Ltd., thickness: 110 μm) as a base sheet. It is coated with a wire bar so that the coating amount after curing becomes 10 g / m ^2, and a 75 μm silicone-coated polyester film (trade name: SP-PET-O5-75) used as a molding base thereon.
B, manufactured by Tosero Corporation). An accelerating voltage of 1 was applied to the multilayer body from the back of the silicone-coated polyester film.
75kV, absorbed dose 4Mrad, oxygen concentration 500ppm
The composition (10) was cured by irradiation with an electron beam under the following conditions. Thereafter, the polyester film was peeled from the resin coating layer to obtain a thermal transfer recording sheet. Evaluation was performed in the same manner as in Example 1. Table 2 shows the evaluation results.

[0075]

[Table 1]

<Footnotes to Table 1> Residues not described in the above table are common to all compositions and are shown below. -OR ¹ O-: dehydrogenation residue of a polycaprolactone diol. R ⁴ : CH ₂ CH ₂ . R ^5: is H.

[0077]

[Table 2]

As is clear from Table 2, the thermal transfer recording sheet according to the present invention had good sublimation dye receptivity and excellent sebum resistance (Examples 1 to 5).
4). Furthermore, if the radiation-curable resin within the scope of the present invention represented by the general formula 1, even if the composition ratio of the two kinds of structures of the organic diisocyanate residue —R ² — changes,
The effects of sublimation dye acceptability and sebum resistance improvement were not changed (Examples 1 and 2). Further, even when the casting method is used (Example 3) or when the layer configuration is two layers (Example 4), the effect of the thermal transfer recording sheet according to the present invention does not change, and it can sufficiently withstand practical use. It was gaining. However, when the radiation-curable resin represented by the general formula 1 according to the present invention is not blended, not only the sebum resistance is poor, but also the sublimation dye acceptability is not always sufficient (Comparative Example 1). ). Further, even if it has the structure of the general formula 1 according to the present invention, when the organic diisocyanate residue -R ² -has a single structure and an aromatic ring structure is not introduced, not only is it inferior to sebum resistance, but also And the sublimation dye acceptability was not satisfactory (Comparative Example 2). On the other hand, when the organic diisocyanate residue -R ² -has a single structure and an aromatic ring structure is introduced and has the structure of the general formula 1 according to the present invention, it has excellent sebum resistance and sublimability. Dye receptivity was also sufficient, but other image storability such as light resistance was inferior,
It was not practically usable (Comparative Example 3). Furthermore, the radiation-cured thermal transfer recording sheet produced by the prior art was not able to simultaneously satisfy the sublimation dye acceptability and sebum resistance, and was not practically usable (Comparative Examples 4 and 5).

[0079]

According to the present invention, at least one radiation-curable resin coating layer is provided on a sheet-like support, and the cured resin layer is formed of radiation-curable 4,4-diphenylmethane diisocyanate and isophorone diisocyanate in the main chain. Sublimation by curing / forming from urethane / unsaturated organo oligomers in which two or more different organic diisocyanates such as tolylene diisocyanate and isophorone diisocyanate, and one of them is introduced with an organic diisocyanate compound having an aromatic ring structure. The present invention provides a thermal transfer recording sheet having excellent dye acceptability and sebum resistance, and is extremely effective in practical use.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Fujii 5-2-1, Nishikujo 5-chome, Nara City, Nara Pref.

Claims (3)

[Claims] 1. A sheet-like support and at least one surface thereof
A coating composition containing a radiation-curable resin is applied on the
And a cured resin layer formed by radiation curing.
In the recording sheet, the following general formula 1 is contained in the coating composition.
Releases urethane and unsaturated organo-oligomer represented by
10% by weight of the radiation curable resin based on the weight of the cured resin layer
Parts or more of the thermal transfer recording sheet, and
In the urethane / unsaturated organo oligomer of the formula 1,
-R^Two-Two or more organic diisocyanate residues having different
And at least one of them has an aromatic ring structure
A thermal transfer recording sheet characterized in that it includes a structure. Embedded image(Where -OR¹O- is a number average molecular weight of 200 to 2000.
Residue of a polymer polyol of the formula^Two− Is organic di
Isocyanate residue, -OR^ThreeO- is dihydroxyl
Indicates the dehydrogenated residue of the hydroxyl group of the compound, CH_Two=
C (R^Five) COOR ^FourO- is an amino group containing one or more double bonds.
Dehydrogenation of (meth) acrylic acid ester containing droxyl group
Residue^FiveIs a hydrogen atom or a methyl group, -OR^FourO
-Indicates a dehydrogenated residue of a dihydric alcohol, respectively. Also, n
Represents an integer of 1 to 100. ) 2. The organic diisocyanate residue —R ² —
2. The thermal transfer recording sheet according to claim 1, wherein the thermal transfer recording sheet comprises two kinds of diisocyanate residues of 4,4-diphenylmethane diisocyanate and isophorone diisocyanate. 3. The organic diisocyanate residue —R ² —
2. The thermal transfer recording sheet according to claim 1, wherein the thermal transfer recording sheet comprises two kinds of diisocyanate residues of 2,4- (2,6-) tolylene diisocyanate and isophorone diisocyanate.