JP2000255170A - Body to be recorded for thermal transfer recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the preservation stability or light resistance of a recorded image by a method wherein a dye accepting layer provided in a base material sheet is formed by including a polyester resin, which is obtained by polycondensing a specified alicyclic dicarboxylic acid or the like and a specified alkane diol and polyhydraulic alcohol component. SOLUTION: A dye accepting layer provided at least on one side of a base material sheet is formed by including a polyester resin, which is obtained by polycondensing a multivalent carboxylic acid component including the alicyclic dicarboxylic acid represented by the formula I and/or its derivative and a polyhydrauic alcohol component including the alkane diol represented by the formula II and a polyhydraulic alcohol having an ether linkage in one molecule and the number average molecular weight of which is set to be 7,500-100,000. In the formulae I and II, R1 and R2 represent a hydrogen atom, a 1-4C alkyl group or an alkylene group, R3 and R4 represent 1-30C alkyl group. Thus, the light resistance of a body to be recorded and the preservation stability of a recorded image are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for thermal transfer recording using a polyester resin for a dye receiving layer of the recording medium.

[0002]

2. Description of the Related Art The thermal transfer recording system has features such as quiet recording, small and inexpensive apparatus, easy maintenance, and short output time. Among them, the sublimation dye thermal transfer method uses a sublimation dye, so that it is possible to easily record with high gradation by continuously changing the amount of heat generated, and it also has features such as high density and high resolution. have. Therefore, compared to other recording methods,
In particular, it is advantageous for obtaining a full-color hard copy, and is widely used as a recording system for a color printer, a video printer, and the like.

In order to obtain a high-quality image on a dye thermal transfer receiving sheet, a receptor layer resin having a high transfer rate and a large amount of dye and having good storability has been studied. Conventionally, various polyester resins have been used as the dyeing resin having such a high transfer speed and dyeing amount and having excellent storage stability. For example, JP-A-57-107885 discloses the use of a saturated polyester resin.
No. 0799 describes an aromatic polybasic acid and 2,2-dialkyl-
It discloses that a polyester resin composed of 1,3-propanediol is used. Further, JP-A-63-797
No. 1 discloses the use of a polyester resin comprising a phenyl group-containing polyol and a dicarboxylic acid.

However, the recording medium of the conventional sublimation type thermal transfer recording system in which the receiving layer contains a polyester resin generally has poor storage stability of the recorded image, and is discolored or discolored by sunlight or fluorescent light. Or, if stored for a long period of time under conditions of high temperature and high humidity, there is a problem that color fading, discoloration, or blurring of an image occurs.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned disadvantages of the prior art and to obtain a recording medium for a sublimation type thermal transfer recording system having excellent storage stability of recorded images, that is, excellent light resistance. It is in.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that 2,6-decalin dicarboxylic acid dimethyl ester and 2-ethyl-2-butyl-1,3- Attention was paid to a polyester resin obtained by polycondensation of propanediol, and among the polyester resins, those having a molecular weight of 10,000 or more were used for a dye receiving layer of a recording medium of a sublimation type thermal transfer recording system. The inventors have found that the light fastness of the body is improved, and have completed the present invention based on this finding.

Thus, according to the present invention, “a base sheet and at least one surface of the base sheet,
A dye receiving layer, wherein the receiving layer has the following general formula (1)
(Wherein R ¹ and R ² represent a hydrogen atom or an alkyl or alkylene group having 1 to 4 carbon atoms) and / or a polycarboxylic acid component containing a derivative thereof. And an alkanediol represented by the following general formula (2) (wherein R ³ and R ⁴ represent an alkyl group having 1 to 30 carbon atoms) and a polyhydric alcohol having an ether bond in the molecule. Having a number average molecular weight (Mn) of 7,500 to 100,
000 ", which is a recording medium for thermal transfer recording characterized by containing a polyester resin of 000.

[0008]

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[0009]

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The specific embodiments of the present invention are as follows. (1) The polyester resin has a number average molecular weight (Mn)
7,500 to 100,000, preferably 10,000
0 to 50,000, more preferably 11,000 to 3
It is in the range of 000. (2) The glass transition point of the polyester resin is usually 20 ° C.
Above, preferably 30-100 ° C, more preferably 40 ° C
~ 80 ° C, most preferably 50-70 ° C.

(3) The polycarboxylic acid component contains 50% by weight or more, preferably 80% by weight or more, and more preferably 90% by weight or more of the alicyclic dicarboxylic acid and / or a derivative thereof represented by the general formula (1). % By weight or more. (4) The polycarboxylic acid component contains a derivative of the alicyclic dicarboxylic acid represented by the general formula (1). (5) The polycarboxylic acid component contains an alicyclic dicarboxylic acid methyl ester represented by the general formula (1). (6) The polycarboxylic acid component is a mixture of an alicyclic dicarboxylic acid and / or a derivative thereof represented by the general formula (1) and an alicyclic-1,4-dicarboxylic acid and / or a derivative thereof. is there. (7) The polyhydric alcohol component is a mixture of the alkanediol of the general formula (2) and a polyhydric alcohol having an ether bond in a molecule. (8) The polycondensation reaction is performed under the condition that the total number [X] of alcoholic reactive groups in all monomers is larger than the total number [Y] of carboxylic acidic reactive groups.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. Polyester Resin The polyester resin used in the present invention comprises a polyvalent carboxylic acid component containing the alicyclic dicarboxylic acid of the general formula (1) and / or a derivative thereof and an alkanediol represented by the general formula (2). It is obtained by polycondensation with a polyhydric alcohol component.

The molecular weight of the polyester resin is 7,500 in terms of polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC).
~ 100,000, preferably 10,000 ~ 50,000
00, more preferably in the range of 11,000 to 30,000. An excessively small molecular weight of the polyester resin is not preferable because fusion between the coated surface and the substrate occurs. On the other hand, if it is excessively large, the viscosity of the coating solution becomes high and the smoothness of the coated surface is inferior.

The glass transition temperature of the polyester resin is usually 20 ° C. or higher, preferably 30 to 100 ° C., more preferably 40 to 80 ° C., and most preferably 50 to 70 ° C.
° C. When the glass transition temperature is in this range, the operability is excellent and suitable.

The hydroxyl value of the polyester resin is as follows:
Usually, 7 mgKOH / g or less, preferably 5 mgKOH / g
/ G or less.

Polyvalent carboxylic acid component The polyvalent carboxylic acid component used as a raw material of the polyester resin used in the present invention contains an alicyclic dicarboxylic acid represented by the general formula (1) and / or a derivative thereof. It is.

Specific examples of the alicyclic dicarboxylic acid represented by the general formula (1) include, for example, decalin-2,6-
Dicarboxylic acid, 3-methyl-decalin-2,6-dicarboxylic acid, 3-ethyl-decalin-2,6-dicarboxylic acid, 3-propyl-decalin-2,6-dicarboxylic acid,
3-butyl-decalin-2,6-dicarboxylic acid, 3,4
-Dimethyl-decalin-2,6-dicarboxylic acid, 3,4
-Diethyl-decalin-2,6-dicarboxylic acid, 3,4
-Dipropyl-decalin-2,6-dicarboxylic acid, 3,
4-dibutyl-decalin-2,6-dicarboxylic acid and the like.

Further, 3,8-dimethyl-decalin-
2,6-dicarboxylic acid, 3,8-diethyl-decalin-
2,6-dicarboxylic acid, 3,8-dipropyl-decalin-2,6-dicarboxylic acid, 3,8-dibutyl-decalin-2,6-dicarboxylic acid, 3-methyl-4-ethyl-decalin-2,6 -Dicarboxylic acid, 3-methyl-4-propyl-decalin-2,6-dicarboxylic acid, 3-methyl-
4-butyl-decalin-2,6-dicarboxylic acid, 3-ethyl-4-butyl-decalin-2,6-dicarboxylic acid and the like.

The derivative of the alicyclic dicarboxylic acid represented by the general formula (1) includes an ester compound, an acid halide and the like. Among them, an ester compound is preferable, and a compound having an ester group having an alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, amyl, and hexyl, is preferable.

The proportion of the alicyclic dicarboxylic acid in the polycarboxylic acid component is usually at least 30% by weight, preferably 50% by weight.
% By weight, more preferably 80% by weight or more.

The polycarboxylic acid component includes an alicyclic-
It can contain 1,4-dicarboxylic acid and / or a derivative thereof. The alicyclic-1,4-dicarboxylic acid is
It has a cyclohexane ring as a basic skeleton of the molecular structure, and has a carboxyl group bonded to carbons at positions 1 and 4. Examples of the derivative of the alicyclic-1,4-dicarboxylic acid include those similar to the derivatives of the alicyclic dicarboxylic acid represented by the general formula (1).

Specific examples of the alicyclic-1,4-dicarboxylic acid include, for example, cyclohexane-1,4-dicarboxylic acid,
2-methyl-cyclohexane-1,4-dicarboxylic acid,
2-ethyl-cyclohexane-1,4-dicarboxylic acid,
2-propyl-cyclohexane-1,4-dicarboxylic acid, 2-butyl-cyclohexane-1,4-dicarboxylic acid, 2-tbutyl-cyclohexane-1,4-dicarboxylic acid, 2,3-dimethyl-cyclohexane-1, 4-dicarboxylic acid, 2,3-diethyl-cyclohexane-1,
4-dicarboxylic acid, 2,3-dipropyl-cyclohexane-1,4-dicarboxylic acid, 2,3-dibutyl-cyclohexane-1,4-dicarboxylic acid, 2-methyl-3-ethyl-cyclohexane-1,4-dicarboxylic acid Acid, 2-methyl-3-propyl-cyclohexane-1,4-dicarboxylic acid, 2-methyl-3-butyl-cyclohexane-
1,4-dicarboxylic acid and the like can be mentioned. These alicyclic groups
1,4-dicarboxylic acid is preferably 30% by weight or less, more preferably 50% by weight or less, in the polycarboxylic acid.

Further, 2-ethyl-3-propyl-cyclohexane-1,4-dicarboxylic acid, 2-ethyl-3-
Butyl-cyclohexane-1,4-dicarboxylic acid, 2-
Methyl-3-tbutyl-cyclohexane-1,4-dicarboxylic acid, and their esters, acid halides, and the like. Among them, cyclohexane-1,4
-Dicarboxylic acids are preferred.

The polyvalent carboxylic acid component may contain another carboxylic acid as long as the effects of the present invention are not impaired. Other carboxylic acids include, for example, aromatic polycarboxylic acids, linear or branched aliphatic polycarboxylic acids, monovalent carboxylic acids and / or derivatives thereof. The allowable amount is usually 10% by weight or less, preferably 5% by weight or less, more preferably 2% by weight or less in the polycarboxylic acid component.

Polyhydric alcohol component The polyhydric alcohol component used as a raw material of the polyester resin used in the present invention has a carbon atom to which a hydrogen atom is not bonded between two carbon atoms to which a hydroxyl group is bonded. An alkanediol having a molecular structure sandwiched between the alkanediol and the alkanediol represented by the general formula (2) and containing a polyhydric alcohol having an ether bond in the molecule.

In the general formula (2), R ³ and R ⁴ each represent an independent alkyl group, the sum of the carbon numbers of each is 1 to 30, and the sum of the carbon numbers of both is 2 to 30. 50,
Preferably it is 3-20, more preferably 3-10.

Specific examples of the above alkyl group include, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, amyl group, hexyl group, heptyl group, octyl group, Nonyl, decyl, dodecyl, tridecyl, pentadecyl, octadecyl, eicosyl and the like.

Of these, methyl, ethyl, propyl, isopropyl, butyl, isobutyl,
A sec-butyl group, an amyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group and the like are preferable, and an ethyl group, a propyl group, a butyl group, a hexyl group and a heptyl group are particularly preferable.

Specific examples of the alkanediol include, for example, 2,2-dimethyl-1,3-propanediol,
2,2-diethyl-1,3-propanediol, 2,2
-Dipropyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, 2-methyl-2-
Hexyl-1,3-propanediol, 2-methyl-2
-Pentyl-1,3-propanediol and the like.

Further, 2-ethyl-2-butyl-1,3
-Propanediol, 2-ethyl-2-pentyl-1,
3-propanediol and the like, among them,
2,2-diethyl-1,3-propanediol, 2,2
-Dipropyl-1,3-propanediol, 2,2-dibutyl-1,3-propanediol, 2-ethyl-2-
Butyl-1,3-propanediol, 2-methyl-2-
Pentyl-1,3-propanediol and the like are preferred.

Examples of the polyhydric alcohol component having an ether bond in the molecule include ethylene oxide of 4,4′-methylenediphenol and / or a diol component of propylene glycol adduct, and ethylene oxide of bisphenol A and / or propylene glycol. Examples of the diol component include an adduct diol component, a biphenol ethylene oxide and / or propylene glycol adduct diol component, diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol. Among them, those having an aromatic ring are preferable, and a diol component of an ethylene oxide adduct of bisphenol A is particularly preferable.

In the polyhydric alcohol, the ratio of the alkanediol represented by the general formula (2) to the polyhydric alcohol having an ether bond in the molecule is (5/95) to (50/95).
50) (molar ratio), preferably (7/93) to (40 /
60) (molar ratio), more preferably (10/90)
(30/70) (molar ratio). By using a mixture of polyhydric alcohols having an ether bond in the molecule, it is possible to easily increase the glass transition temperature of the obtained polyester resin, and to increase sensitivity by improving affinity for the dye. be able to.

The proportion of the above mixture in the polyhydric alcohol component is usually 80 to 100% by weight, preferably 90 to 100% by weight.
%, More preferably in the range of 95 to 100% by weight.

The polyhydric alcohol component may contain another alcohol. Other polyhydric alcohols include, for example, alkane diols other than the alkane diol represented by the general formula (2), alicyclic diols, and aromatic diols. Further, a monohydric alcohol may be contained as long as the effect of the present invention is not impaired, and its allowable amount is usually 10% by weight or less, preferably 5% by weight or less, more preferably 5% by weight or less in the polyhydric alcohol component. Not more than 3% by weight.

The method for producing a polyester resin used in the present invention is to synthesize a polyester resin by polycondensing a polyvalent carboxylic acid component and a polyhydric alcohol component.

The polycondensation reaction is carried out according to a conventional method, for example, at a reaction temperature of 100 to 300 ° C., preferably 150 to 280.
C., more preferably at 180 to 230 C., particularly preferably in the presence of an inert gas. If necessary, a water-insoluble organic solvent azeotropic with water, such as toluene or xylene, may be used. The reaction is carried out under reduced pressure, that is, usually 0.1 to 200 mmHg, preferably 0.1 to 200 mmHg.
5 to 100 mmHg, more preferably 1 to 30 mmHg
It is also possible to carry out.

In the polycondensation reaction, an esterification catalyst is usually used. Examples of the esterification catalyst include, for example, Bronsted acids such as paratoluenesulfonic acid, sulfuric acid, and phosphoric acid, calcium acetate, zinc acetate, manganese acetate, zinc stearate, alkyltin oxide, dialkyltin oxide, and titanium alkoxide. Examples include organometallic compounds, metal oxides such as tin oxide, antimony oxide, titanium oxide, and vanadium oxide. Of these, organometallic compounds belonging to Group IV of the periodic table are preferable from the viewpoint of the oxidation stability of the obtained polyester.

In the polycondensation reaction, the total number [X] of alcoholic reactive groups in all monomers obtained by summing all polyhydric carboxylic acid components and all polyhydric alcohol components becomes the total number [Y] of carboxylic acidic reactive groups. It is preferable to increase the molecular weight of the polyester resin and to increase the hydroxyl value. Total number of alcoholic reactive groups [X]
And the total number of carboxylic acid reactive groups [Y] is:
[X] / [Y] is usually 1.00 or more, preferably 1.
The range is from 01 to 1.20, more preferably from 1.02 to 1.10.

Here, the alcoholic reactive group is an alcoholic functional group that forms an ester bond.
Usually, a hydroxyl group and the like are mentioned, and the carboxylic acid reactive group is a carboxylic acid functional group which forms an ester bond, and usually includes a carboxyl group, an ester group, an acid anhydride and the like.

Formation of Dye Receiving Layer The dye receiving layer according to the present invention can be formed on a substrate sheet by a known method. When forming the dye-receiving layer, the polyester resin of the present invention may be used alone or as a mixture. Further, other thermoplastic resins, for example, polyolefin resins such as polypropylene, polychlorinated resins, and the like. Halogenated polymers such as vinyl and polyvinylidene chloride, vinyl polymers such as polyvinyl acetate and polyacrylic ester, polystyrene resins, polyamide resins, copolymer resins of olefins such as ethylene and propylene with other vinyl monomers, ionomers And cellulose-based resins such as cellulose diacetate and polycarbonate. The proportion of the polyester resin of the present invention in the resin mixture is preferably 20 to 100%,
More preferably, it is 50 to 100%.

The substrate sheet used in the recording medium for thermal transfer recording of the present invention is not particularly limited, and any known sheet-like substrate can be used. General specific examples of the sheet-like substrate are shown below. (1) synthetic paper (synthetic paper of polyolefin type, polystyrene type, polyester type, etc.), (2) high quality paper, art paper,
Coated paper, cast coated paper, wallpaper, backing paper, synthetic resin or emulsion impregnated paper, synthetic rubber latex impregnated paper, synthetic resin internal paper, paperboard, cellulose fiber paper, polyolefin coated paper (especially paper coated on both sides with polyethylene) )), And (3) plastic films or sheets such as polyolefins such as polypropylene and polyethylene, polyvinyl chloride, polyethylene terephthalate, polystyrene, methacrylate, polycarbonate, polyimide, polyamide, and polyamideimide, and white reflectivity to this plastic. Films or sheets that have been given a treatment.

The recording medium of the present invention can be applied to various uses such as continuous or sheet-fed sheets, cards, and transmissive original making sheets, which can be thermally transferred, by appropriately selecting a base sheet. You can also. Further, the recording medium of the present invention can be provided with a cushion layer between the base sheet and the dye-receiving layer as needed. By providing such a cushion layer, noise during printing is reduced and image information is reduced. A corresponding image can be transferred and recorded with good reproducibility. The thermal transfer sheet used when performing thermal transfer using the recording medium of the present invention as described above is provided with a dye layer containing a sublimable dye on paper or polyester film,
Any conventionally known thermal transfer sheet can be used as it is in the present invention.

In the recording medium of the present invention, the above-mentioned resin and other necessary additives such as a releasing agent, a crosslinking agent, a curing agent, a catalyst, A dispersion obtained by dissolving a release agent, an ultraviolet absorber, an antioxidant, a light stabilizer and the like in an appropriate organic solvent or dispersing in an organic solvent or water, for example, gravure printing, screen printing Coating method and a drying method using a gravure plate, a reverse roll coating method using a gravure plate, or a wire bar coating method. In the formation of the dye-receiving layer, pigments such as titanium oxide, zinc oxide, kaolin clay, calcium carbonate, and finely powdered silica are used for the purpose of improving the whiteness of the dye-receiving layer to further enhance the sharpness of the transferred image. Agents can be added.

The dye-receiving layer formed as described above may be of any thickness, but generally the thickness of the dye-receiving layer is 0.5 to 5
It is preferably about 0 μm, more preferably 4 to 10 μm. If the thickness of the dye receiving layer is too small, the density and sensitivity of the image decrease, and the uniformity of the image deteriorates due to the limitation of coating accuracy. On the other hand, if it is too thick, the effect of the obtained dye-receiving layer is saturated, which is not only uneconomical, but also lowers the strength of the dye-receiving layer. Further, such a dye receiving layer is preferably a continuous coating, but may be formed as a discontinuous coating using a resin emulsion or a resin dispersion.

In the present invention, the dye receiving layer can be formed by a transfer method. That is, as the substrate sheet, for example, when pulp paper or the like is used, the substrate may have insufficient surface smoothness, and in this case, the dye receiving layer formed by the coating method may have irregularities or irregularities. Although a pinhole or the like may occur, such a problem does not occur according to the transfer method. The transfer method includes, for example, forming the above-mentioned dye-receiving layer on a film having good release properties such as a polyester film, and further forming an appropriate pressure-sensitive adhesive layer or an adhesive layer on the surface thereof, Is bonded to the pulp paper substrate surface with a laminator or the like, and then the polyester film is peeled off. When the intermediate layer is formed, the intermediate layer may be formed on the surface of the pulp paper in advance, or may be provided on the surface of the dye receiving layer on the film.

In the present invention, the dye-receiving layer may be crosslinked to prevent blocking and sticking during printing. As the isocyanate that can be used as a crosslinking agent component when performing thermal crosslinking, any of the conventionally known isocyanate compounds can be used as it is. Specific examples thereof include diphenylmethane diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, and tolylene diisocyanate. Further, a crosslinking accelerator such as dibutyltin dilaurate may be added for the purpose of promoting crosslinking.

In the case where crosslinking is carried out by active energy rays, monomers and oligomers having an acryloyloxy group or a methacryloyloxy group as a polymerizable group are preferably used as a crosslinking agent.

As such monomers and oligomers, polyether acrylate or polyether methacrylate (hereinafter, “acrylate or methacrylate” is simply abbreviated as “(meth) acrylate”), polyester (meth) acrylate, polyol ( Monomer / oligomers such as (meth) acrylate type, epoxy (meth) acrylate type, amide urethane (meth) acrylate type, urethane (meth) acrylate type, spiro acetal (meth) acrylate type, and polybutadiene (meth) acrylate type it can. Specifically, polyether (meth) acrylate synthesized from 1,2,6-hexanetriol / propylene oxide / acrylic acid, trimethylolpropane / propylene oxide / acrylic acid; adipic acid / 1,6-
Polyester (meth) acrylate synthesized from hexanediol / acrylic acid, succinic acid / trimethylolethane / acrylic acid; triethylene glycol diacrylate, hexapropylene glycol diacrylate, neopentyl glycol diacrylate, 1,4-
Butanediol dimethacrylate, 2-ethylhexyl acrylate, tetrahydrofurfuryl acrylate,
2-hydroxyethyl methacrylate, ethyl carbitol acrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, 2,2-bis (4-
Acryloyloxydiethoxyphenyl) propane,
(Meth) acrylate or polyol (meth) acrylate such as 2,2-bis (4-acryloyloxypropoxyphenyl) propane; diglycidyl etherified bisphenol A / acrylic acid, diglycidyl etherified polybisphenol A / acrylic acid, triglycidyl Epoxy (meth) acrylates such as etherified glycerin / acrylic acid; γ-butyrolactone / N-methylethanolamine / bis (4-isocyanatocyclohexyl) methane / 2-hydroxyethyl acrylate, γ-butyrolactone / N-methylethanolamine / 2,6-tolylene diisocyanate / tetraethylene glycol / 2
Amide urethane (meth) acrylates such as -hydroxyethyl acrylate; urethane acrylates such as 2,6-tolylene diisocyanate diacrylate, isophorone diisocyanate diacrylate, hexamethylene diisocyanate diacrylate; dialylidenepentaerythritol / 2-hydroxyethyl acrylate Spiro acetal acrylate synthesized; acrylated polybutadiene synthesized from epoxidized butadiene / 2-hydroxyethyl acrylate, and the like.
These monomers and oligomers are used alone or in a mixture of two or more.

When ultraviolet rays which can be easily handled are used as active energy rays, a photopolymerization initiator is further added to the resin component.
It is preferable to add 0.1 to 10 parts by weight to 100 parts by weight. Specific examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2
-Methylpropiophenone, benzyldimethyl ketal and the like. When an electron beam is used as the active energy beam, it is not necessary to use an initiator or the like, and it is general to cure by adding only a crosslinking agent. In consideration of productivity, an acryloyloxy group is used as the crosslinking agent. Are preferred in view of the crosslinking speed.

The dye receiving layer of the present invention preferably contains a release agent for the purpose of further improving the releasability of the dye receiving layer and the transfer sheet. Examples of the release agent include a silicone-based surfactant, a fluorine-based surfactant, a graft polymer having a polyorganosiloxane as a trunk or a branch, a compound capable of forming a silicon-based or fluorine-containing crosslinked structure, such as amino-modified silicon and epoxy. Combinations of modified silicon can be mentioned, and these release agents can be used alone or in combination. The amount of the release agent used is not particularly limited, but is preferably 0.01 to 30 parts by weight based on 100 parts by weight of the total of the polyester resin and the crosslinkable component.

In the present invention, an ultraviolet absorber may be contained for the purpose of further improving the light fastness of the dye receiving layer.
As the ultraviolet absorber, a known benzotriazole-based or benzophenone-based ultraviolet absorber can be used. For example, as a specific example of a benzotriazole-based ultraviolet absorber, 2- (5-methyl-2-hydroxyphenyl) benzotriazole (manufactured by Ciba Geigy: TINU)
VINP), 2- [2-hydroxy-3,5-bis (α, α-dimethyl-benzyl) phenyl] -2-benzotriazole (manufactured by Ciba Geigy: TINUVIN 2
34), 2- (5-t-butyl-2-hydroxyphenyl) benzotriazole (manufactured by Ciba Geigy: TINUV)
IN PS), 2- (3,5-di-t-butyl-2-hydroxyphenyl) benzotriazole (manufactured by Ciba Geigy: TINUVIN 320), 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (manufactured by Ciba Geigy: TINUVIN
326), 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chlorobenzotriazole (manufactured by Ciba Geigy: TINUVIN 327), 2- (3,5
-Di-t-amyl-2-hydroxyphenyl) benzotriazole (manufactured by Ciba Geigy: TINUVIN32)
8), 2- [2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl] benzotriazole (SUMIS, manufactured by Sumitomo Chemical Co., Ltd.)
ORB 250), 2- (4-octoxy-2-hydroxyphenyl) benzotriazole and the like.

Specific examples of the benzophenone type ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-
4-dodecyloxybenzophenone, 2-hydroxy-
4-benzyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2 ', 4,
4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone,
2'-dihydroxy-4,4'-dioctoxybenzophenone, 2,2'-dihydroxy-4,4'-didodecyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone and the like.

These ultraviolet absorbers can be used alone or in combination of two or more. Although the amount of use is not particularly limited, it is desirable to include 0.1 to 30 parts by weight based on 100 parts by weight of the total of the polyester resin and the crosslinkable component. If the amount is too small, the effect of improving the light resistance is not sufficient, while if it is too large, the ultraviolet absorbent may bleed out to the surface of the dye receiving layer or the recorded image may bleed over time.

For the purpose of further improving the light fastness of the dye receiving layer, a hindered amine light stabilizer may be further contained. Known hindered amine light stabilizers can be used. Specifically, screws (2, 2, 6,
6-tetramethyl-4-piperidyl) sebacate (manufactured by Sankyo: SANOL LS770), bis (1,2,2,6,6)
-Pentamethyl-4-piperidyl) sebacate (manufactured by Sankyo: SANOL LS765), 1- {2- [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyloxy] ethyl {-4- [3- (3,5-
Di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine (manufactured by Sankyo: SANOL LS2626), 4-benzoyloxy-2,2,6,6-tetramethylpiperidine (Manufactured by Sankyo: SANOL LS744), 8-acetyl-3-
Dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro [4,5] decane-2,4-dione (manufactured by Sankyo: SANOL LS440), 2- (3,5-di-t
-Butyl-4-hydroxybenzyl) -2-n-butylmalonate bis (1,2,2,6,6-pentamethyl-4-piperidyl) (manufactured by Ciba-Geigy: TINUVIN 14)
4), bis (2,2,6,6-tetramethyl-4 succinate)
-Piperidinyl) ester (manufactured by Ciba-Geigy: TINU)
VIN 780FF), dimethyl succinate and 1- (2-
(Hydroxyethyl) -4-hydroxy-2,2,6,6-
Polycondensate of tetramethylpiperidine (Ciba Geigy:
TINUVIN 622LD), poly {[6- (1,1,
3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,
2,6,6-tetramethyl-4-piperidyl) imino]｝
(Ciba Geigy: CHIMASSORB 944L
D), N, N'-bis (3-aminopropyl) ethylenediamine and 2,4-bis [N-butyl-N- (1,2,2,
6,6-pentamethyl-4-piperidyl) amino] -6
-Polycondensate of chloro-1,3,5-triazine (manufactured by Ciba Geigy: CHIMASSORB 119FL), HA-
70G (manufactured by Sankyo), Adekastab LA-52, Adekastab LA-57, Adekastab LA-62, Adekastab LA-67, Adekastab LA-63, Adekastab LA-68, Adekastab LA-82,
Adekastab LA-87 (all manufactured by Asahi Denka Kogyo) and the like.

These hindered amine light stabilizers include:
Although they can be used alone or in combination of two or more, it is preferable to use them together with the above-mentioned ultraviolet absorber in consideration of the effect of improving light resistance. The amount of the hindered amine light stabilizer is not particularly limited, but is 0.1 to 0.1 parts by weight based on the total of 100 parts by weight of the polyester resin and the crosslinkable component.
It is desirable to contain 30 parts by weight. If the amount is too small, the effect of improving light resistance is not sufficient, and if it is too large,
The hindered amine light stabilizer may bleed out to the surface of the dye receiving layer, or the recorded image may bleed over time.

For the purpose of further improving the light fastness of the dye receiving layer, an antioxidant may be further contained. As the antioxidant, known phenolic antioxidants, amine antioxidants, sulfur antioxidants, phosphorus antioxidants and the like can be used. These antioxidants can be used alone or in combination of two or more. Although the amount of use is not particularly limited, it is desirable to include 0.1 to 20 parts by weight based on 100 parts by weight of the total of the polyester resin and the crosslinkable component. If the amount is too small, the effect of improving light resistance is not sufficient, while if it is too large, the antioxidant may bleed out to the surface of the dye receiving layer or the recorded image may bleed over time.

The dye-receiving layer of the present invention may further contain an inorganic filler such as silica, calcium carbonate, titanium oxide or zinc oxide, a fluorescent dye for adjusting the color tone of the image-receiving layer, or blue or violet depending on the purpose of use. It is also possible to add such a dye to the dye receiving layer as needed.

The above additives such as an ultraviolet absorber, a light stabilizer and an inorganic pigment are conveniently mixed with a dye-receiving layer resin which is a main component of the dye-receiving layer for coating.
Another coating layer may be applied above or below the dye receiving layer.

In order to prevent static electricity from being generated when the recording medium travels inside the printer and cause a traveling trouble,
An antistatic agent may be added to at least one side of the sheet by adding it to the dye-receiving layer or by disposing a back coat containing the same. As the antistatic agent, a cationic hydrophilic polymer is often used.

[0060]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Parts and percentages in these examples are on a weight basis unless otherwise specified.

(1) Number Average Molecular Weight The number average molecular weight (Mn) of the polyester was calculated as a standard polystyrene equivalent amount according to the GPC method.

(2) Sensitivity (Dye Dye Concentration) A commercially available color video printer (manufactured by SONY: UP-5)
500), printing a single color of cyan in density step printing
The dyeing density in step 9 was evaluated with a Macbeth densitometer (RD-914, manufactured by Sakata Inx, using an A filter).

(3) Light fastness A sample printed stepwise under the same conditions as described above was subjected to 370 W / m ^{2 at} a temperature of 63 ° C. in a xenon arc fade ometer (manufactured by Atlas: Ci35, using a borosilicate glass filter / soda lime glass filter). , Humidity 50% RH
After processing in the medium for 72 hours, the residual dye ratio in Step 9 was measured using a Macbeth densitometer (RD-914, A manufactured by Sakata Inx).
Using a filter).

(4) Storage stability A sample printed stepwise under the same conditions as above was used at 60 ° C., 85
% RH for 14 days, and then the residual dye ratio was measured using a Macbeth densitometer (RD-914, A manufactured by Sakata Inx).
Using a filter).

<Synthesis Example 1> 100 parts of dimethyl decalin-2,6-dicarboxylate, 2-ethyl-2-butyl-1,
A polycondensation reaction was carried out using 9.7 parts of 3-propanediol, 111.2 parts of an adduct of bisphenol A ethylene oxide, and 0.22 parts of monobutyltin oxide as a catalyst to obtain a polyester resin (polyester resin A). The number average molecular weight was 14,160. The equivalent ratio (OH / COOH, hereinafter the same) between the alcoholic reactive group (OH) and the carboxylic acidic reactive group (COOH) in the system is 1.02.

<Synthesis Example 2> In the same manner as in Synthesis Example 1, 100 parts of dimethyl decalin-2,6-dicarboxylate, 67.6 parts of cyclohexane-1,4-dicarboxylic acid, and 2-ethyl-2-butyl-1 , 3-propanediol 19.2
Part, bisphenol A ethylene oxide adduct 22
A polyester resin (polyester resin B) was obtained using 2.2 parts and 0.44 parts of monobutyltin oxide (OH / COOH = 1.02). The number average molecular weight is 14,
530.

<Synthesis Example 3> As in Synthesis Example 1, 100 parts of dimethyl decalin-2,6-dicarboxylate, 67.6 parts of cyclohexane-1,4-dicarboxylic acid, 2,2-
Dimethyl-1,3-propanediol 12.6 parts, bisphenol A ethylene oxide adduct 217.2 parts,
Using 0.4 parts of monobutyltin oxide (OH / C
OOH = 1.02) A polyester resin (polyester resin C) was obtained. The number average molecular weight was 14,020.

<Synthesis Example 4> In the same manner as in Synthesis Example 1, 100 parts of dimethyl decalin-2,6-dicarboxylate, 130.8 parts of an ethylene oxide adduct of bisphenol A, and 0.23 part of monobutyltin oxide were used to prepare (OH). / CO
OH = 1.02) A polyester resin (polyester resin D) was obtained. The number average molecular weight was 15,320.

<Synthesis Example 5> In the same manner as in Synthesis Example 1, 100 parts of cyclohexane-1,4-dicarboxylic acid, 193.3 parts of an adduct of bisphenol A ethylene oxide, and 0.29 part of monobutyltin oxide were used (OH). / C
OOH = 1.02) A polyester resin (polyester resin E) was obtained. The number average molecular weight was 15,940.

<Synthesis Example 6> As in Synthesis Example 1, 100 parts of dimethyl decalin-2,6-dicarboxylate, 2,2
Using 42 parts of dimethyl-1,3-propanediol and 0.14 part of monobutyltin oxide (OH / CO
OH = 1.025), and a polyester resin (polyester resin F) was obtained. The number average molecular weight was 3,860.

<Examples 1 to 3 and Comparative Examples 1 to 3> 100 parts of each of the above-mentioned six kinds of polyester resins (polyester resins A to F), 8 parts of isocyanate (Coronate L, manufactured by Nippon Polyurethane Industry), and silicone oil 3 Part, ultraviolet absorber (TINUVIN320 manufactured by Ciba-Geigy) 0.5
Part is toluene / methyl ethyl ketone = 1/1 (weight ratio)
Was dissolved in 444 parts of a mixed solvent and stirred to prepare a coating solution. A synthetic paper (made by Oji Yuka Synthetic Paper, thickness 110 μm) was used as a base sheet, and a coating solution was applied to one surface of the base sheet with a # 24 wire bar so that the coating liquid became 5.0 μm when dried. For 1 minute. Then, at 50 ° C, 4
Crosslinking treatment was performed for one day to obtain a recording medium for thermal transfer recording, and the sensitivity, light resistance, and storage stability were evaluated for these. Table 1 shows the results.

Example 4 100 parts of polyester resin B
, 8 parts of dipentaerythritol caprolactam-modified acrylate, 3 parts of silicone oil, and 0.5 part of an ultraviolet absorber (TINUVIN 320 manufactured by Ciba Geigy) in a mixed solvent of toluene / methyl ethyl ketone = 1/1 (weight ratio) 4
The solution was dissolved in 44 parts and stirred to prepare a coating solution. Next, coating and drying are performed in the same manner as in the case of thermal crosslinking, and an accelerating voltage of 175 is applied.
Crosslinking was carried out at a radiation dose of 4 Mrad using a curtain electron beam accelerator at kV and a beam current of 5 mA to obtain a recording medium for thermal transfer recording. Also for this, sensitivity, light fastness and storage stability were evaluated, and the results are shown in Table 1.

[0073]

[Table 1]

From the results shown in Table 1, the alicyclic dicarboxylic acid represented by the general formula (1) was used as the polyvalent carboxylic acid component, and the alkane represented by the general formula (2) was used as the polyhydric alcohol component. The polyester resin (Synthesis Examples 1 to 4) obtained by polycondensation using a mixture of a diol and a polyhydric alcohol having an ether bond in the molecule (Synthesis Examples 1 to 4), in which the dye receiving layer (Examples 1 to 4) has a sensitivity It can be seen that they are excellent in light resistance and storage stability. Among them, those obtained by further adding an alicyclic-1,4-dicarboxylic acid as a polyhydric alcohol component (Examples 2 to 4) are the most excellent. On the other hand, in the case of the polyester resin having no hindered glycol component (Comparative Example 1), the light resistance is not improved. In the case of a polyester resin having no decalin dicarboxylic acid component (Comparative Example 2) and in the case of a polyester resin having an excessively low molecular weight (Comparative Example 3), the sensitivity,
Light resistance and storage stability are not improved.

[0075]

As described above, according to the present invention, a recording medium for thermal transfer recording can be obtained in which the disadvantages of the prior art are improved and storage stability of a recorded image, that is, light resistance is excellent. The image of the recording medium of the present invention does not fade or discolor even when stored for a long period of time under the conditions of sunlight, fluorescent light, and high temperature and high humidity, and the image is less likely to blur.

Continued on the front page (72) Inventor Rihide Sato 1-10-6 Shinonome, Koto-ku, Tokyo Oji Paper Co., Ltd. Shinonome Research Center (72) Inventor Shizuo Kitahara 1-2-1, Yoko, Kawasaki-ku, Kawasaki-ku, Kanagawa Prefecture No. Within the Zeon Corporation Integrated Development Center (72) Atsushi Hayashi Inventor 1-2-1, Yasuko, Kawasaki-ku, Kawasaki City, Kanagawa Prefecture F-term (reference) 2H111 AA27 CA03 CA30 4F100 AK41B AK41C AK41K AR00B AR00C AT00A BA02 BA03 BA06 BA10A BA10B BA10C GB90 JA07B JA07C JD14B JD14C JL00 YY00B YY00C

Claims (2)

[Claims] 1. An alicyclic dicarboxylic acid represented by the general formula (1), comprising: a base sheet; and a dye receiving layer provided on at least one surface of the base sheet. (Wherein R ¹ and R ² represent a hydrogen atom or an alkyl group or alkylene group having 1 to 4 carbon atoms) and / or a polyvalent carboxylic acid component containing a derivative thereof; Alkanediol represented by the general formula (2) (wherein,
R ³ and R ⁴ represent an alkyl group having 1 to 30 carbon atoms. ) And a polyester resin having a number average molecular weight (Mn) of 7,500 to 100,000, obtained by polycondensing a polyhydric alcohol component containing a polyhydric alcohol having an ether bond in the molecule. A recording medium for thermal transfer recording, comprising: Embedded image 2. The recording medium for thermal transfer recording according to claim 1, wherein the polyvalent carboxylic acid component further contains cyclohexane-1,4-dicarboxylic acid and / or a derivative thereof.