JPH11198549A - Polyester resin composition for sublimation type thermal transfer image receiving material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sublimation transfer image receiving material maintaining durability of an image while the image of high sensitivity and high image quality is maintained as it is. SOLUTION: For a polyester resin composition for a sublimation type thermal transfer image receiving body having a copolymer polyester resin of 40 deg.C or higher in glass transition temperature and 0.10 dl/g or over in reduced viscosity as a principal constituent, in a glycol constituent constituting the copolymer polyester resin, a diethylene glycol is of 10 mol.% or over, and a glycol having a cyclic structure is of 20 mol.% or over.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester resin composition for a sublimation transfer image receptor used in combination with a thermal transfer sheet containing a sublimation dye.

[0002]

2. Description of the Related Art In a sublimation type thermal transfer system, a thermal transfer sheet coated with a sublimable dye is heated by a thermal head or the like, so that the sublimable dye is transferred onto a sublimation transfer image receiving member in contact with the thermal transfer sheet to print a printed image. It is a way to get.

As the dyeing resin used in the dyeing layer of the above-described sublimation transfer image receptor, JP-A-57-107885, JP-A-60-64899, and JP-A-61-25.
8790 gazette, JP-A-62-105689, etc.
Conventionally, those containing a saturated polyester as a main component have been disclosed.

[0004]

Conventionally, when a saturated polyester is used as the resin for the dyeing layer, a high-quality image with good color density, gradation and color reproducibility can be obtained. On the other hand, the recorded image is closely related to the state of storage of the dye, and although there are some points that are not as good as the image storage of silver halide color photographs due to the study of the resin design for the dyeing layer, considerable storage stability was obtained. Has reached a certain level. However, when compared with silver halide color photographs, the above-described system in which the dye image-receiving layer is exposed to the surface has a fundamental problem in long-term storage in terms of image distortion after storage.

[0005] As an example of improving the problem, when a resin for a dyeing layer is used with emphasis on storability, a defect such as a decrease in dyeing sensitivity and a reduction in printing speed occurs. To solve these problems, methods such as accelerating the printing speed of printers have been adopted.However, the conventional polyester resin has low heat resistance in the high-density printing area, so the image surface has a rough image quality. There were problems such as becoming.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sublimation transfer image receiving body which maintains image durability while maintaining high sensitivity and high quality images. The present inventors have conducted intensive studies on the sublimation transfer image receptor in order to achieve the above object, and as a result, have found that a copolymerized polyester resin having a specific physical property and composition is useful, and reached the present invention. . That is, the present invention relates to a polyester resin composition for a sublimation-type thermal transfer image receptor, comprising a copolymerized polyester resin having a glass transition temperature of 40 ° C. or higher and a reduced viscosity of 0.10 dl / g or higher as a main component. A polyester resin composition for a sublimation-type thermal transfer receiver, characterized in that at least 10 mol% of the glycol component constituting the copolymerized polyester resin is diethylene glycol and at least 20 mol% is a glycol having a cyclic structure.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a sublimation type thermal transfer image receptor is a recording material from which an image can be obtained by transferring a sublimable dye to a dyeing layer.

The glycol component in the copolymerized polyester resin of the present invention is characterized in that diethylene glycol is at least 10 mol% with respect to all glycol components, and the glycol component having a cyclic structure is at least 20 mol% with respect to all glycol components. It is to be. More preferably, the proportion of diethylene glycol in the glycol component is at least 15 mol% in all glycol components, and the proportion of the glycol component having a cyclic structure is at least 30 mol% in all glycol components. If the resin system does not contain these two components in necessary amounts, the surface quality of the high-density printing portion is rough, and the sharpness of the image is reduced. The glycol component having a cyclic structure in the present invention is a glycol having an aromatic skeleton and / or an alicyclic skeleton.

The aromatic-containing glycols include para-xylene glycol, meta-xylene glycol, ortho-xylene glycol, 1,4-phenylene glycol,
Two phenolic hydroxyl groups of bisphenols such as ethylene oxide adduct of 4-phenylene glycol, bisphenol A, ethylene oxide adduct of bisphenol A, and propylene oxide adduct are each provided with 1 to several moles of ethylene oxide or propylene oxide. Glycols obtained by addition are exemplified.

The alicyclic glycols include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, tricyclodecanediol, tricyclodecanedimethylol, spiroglycol, hydrogenated bisphenol A, hydrogenated Examples thereof include an ethylene oxide adduct and a propylene oxide adduct of bisphenol A.

In the copolyester resin of the present invention, the dicarboxylic acid component is composed of 60 to 100 mol% of aromatic dicarboxylic acid and / or alicyclic dicarboxylic acid and 0 to 40 mol% of aliphatic dicarboxylic acid. Is particularly preferred from the viewpoint of maintaining the heat resistance.

The aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, diphenic acid, sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfophthalic acid, and 4-sulfonaphthalene- 2,7 dicarboxylic acid,
5- (4-sulfophenoxy) isophthalic acid, sulfoterephthalic acid, and / or aromatic dicarboxylic acids such as metal salts and ammonium salts thereof, and aromatic oxy acids such as p-hydroxybenzoic acid p- (hydroxyethoxy) benzoic acid Carboxylic acids and the like can be mentioned.

Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and acid anhydrides thereof. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecandionic acid, and dimer acid.

Examples of the glycol which can be used other than diethylene glycol and glycol having a cyclic structure include, for example, ethylene glycol, 1,2-propylene glycol,
1,3-propanediol, 1,4-butanediol,
1,5-pentanediol, neopentyl glycol,
1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-
Examples thereof include aliphatic glycols such as 2-butylpropanediol, neopentyl glycol hydroxypivalate, dimethylol heptane, and 2,2,4-trimethyl-1,3-pentanediol.

Examples of ether bond-containing glycols other than diethylene glycol include triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol ethylene oxide adduct, neopentyl glycol propylene oxide adduct, and the like. Is mentioned.

Other components that can be used to obtain the copolymerized polyester resin of the present invention include fumaric acid, maleic acid, maleic anhydride, itaconic acid and citraconic acid as unsaturated dicarboxylic acids.
Tri and tetracarboxylic acids such as trimellitic acid and pyromellitic acid can be exemplified.

The copolyester resin of the present invention can be modified to a polyurethane resin as required. The polyurethane resin is composed of, for example, a polyester polyol (a), an organic diisocyanate compound (b), and, if necessary, a chain extender (c) having an active hydrogen group, and has a molecular weight of 500 to 10,000.
0, urethane bond content is 500-4000 equivalent / 10
One having a configuration of 6 g is exemplified. The polyester polyol (a) is produced by using the compounds already exemplified in the section of the polyester resin as the dicarboxylic acid component and the glycol component, both terminal groups or side chains are hydroxyl groups, and the molecular weight is 500 to 10,000. Things are desirable.

The organic diisocyanate compound (b) used in the present invention includes hexamethylene diisocyanate,
Tetramethylene diisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate, p-xylylene diisocyanate, m-xylylene diisocyanate, 1,3-diisocyanatomethylcyclohexane, 4,4′-diisocyanate dicyclohexane,
4,4′-diisocyanate cyclohexylmethane, isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, p-phenylene diisocyanate, diphenylmethane diisocyanate, m-phenylene diisocyanate, 2,4-
Naphthalene diisocyanate, 3,3'-dimethyl-
4,4'-biphenylenediisocyanate, 4,4'-
Examples include diisocyanate diphenyl ether, 1,5-naphthalenediisocyanate, and the like.

In the present invention, as the chain extender (c) having an active hydrogen group, which is used if necessary, for example, ethylene glycol, propylene glycol, neopentyl glycol, 2,2-diethyl-1,3-propane Examples thereof include glycols such as diol, diethylene glycol, spiro glycol, and polyethylene glycol, and amines such as hexamethylene diamine, propylene diamine, and hexamethylene diamine.

The above polyurethane resin is produced in a known manner at a reaction temperature of 20 to 150 ° C. in a solvent in the presence or absence of a catalyst. As the solvent used at this time, for example, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, and esters such as ethyl acetate and butyl acetate can be used. As a catalyst for accelerating the reaction, amines, organotin compounds and the like are used.

The reduced viscosity of the polyester resin of the present invention is 0.10 dl / g or more, preferably 0.15 dl / g.
/ G or more. When the reduced viscosity is less than 0.10 dl / g, the strength required as a coating film for the dyeing layer is reduced.

The glass transition temperature of the polyester resin of the present invention is 40 ° C. or higher, preferably 50 ° C. or higher. If the temperature is lower than 40 ° C., the coating film is severely blocked, which is not preferable for practical use as an image receiving paper, and the image durability is not exhibited due to poor heat resistance.

The following resins can be used in combination with the above-mentioned polyester resin used for the sublimation transfer image receptor. That is, examples of resins that can be used in combination include polyvinyl resins, polycarbonate resins, polyacrylic resins, polyester resins, polymethacrylate resins, polyolefin resins, cellulose derivative resins, polyether resins, vinyl chloride and modified resins thereof.

In order to further improve the durability, the polyester resin of the present invention may be thermoset or crosslinked.
Examples of the curing agent for heat curing include silicone resin, melamine resin, phenol-formalin resin, epoxy resin, and isocyanate resin. The crosslinking includes ionic crosslinking and radiation crosslinking.

The resin used for the image receiving paper of the sublimation transfer image receiving member is not particularly limited, but the following resins can be used. That is, usable resins include polyvinyl resins, polycarbonate resins, polyacryl resins, polyester resins, polymethacrylate resins, polyolefin resins, cellulose derivative resins, polyether resins, vinyl chloride and modified resins thereof.

The image receiving body of the present invention may contain an ultraviolet absorber, an antioxidant and the like for the purpose of improving the light fastness of the recorded image.

When the polyester resin of the present invention is used as an image-receiving member, the polyester resin of the present invention is
% By weight or more, more preferably 5 to 100% by weight.

When the present resin is coated on a substrate, the polyester resin of the present invention and other resins and additives which are added as necessary are dissolved in a solvent and coated, or a non-aqueous dispersion, It can be used in the form of an aqueous dispersion or an aqueous solution (no solvent). The solution or dispersion used for coating the substrate is usually used at a solid concentration of about 1 to 70% by weight.

The substrate used for the sublimation transfer image receptor is not particularly limited, and examples thereof include paper, synthetic paper, various films, various sheets, metal plates, glass plates, cloths, and nonwoven fabrics.

In the sublimation transfer image receptor of the present invention, if necessary, an image protective layer may be provided on the image receiving layer. As the resin used for the image protection layer, polyvinyl resin,
Examples thereof include polycarbonate resin, polyacryl resin, polyester resin, polymethacrylate resin, polyolefin resin, cellulose derivative resin, polyether resin, vinyl chloride and modified resins thereof.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. In the examples, “parts” means “parts by weight”, and “%” means “% by weight”. The present invention is not particularly limited by the examples.

(1) Glass transition temperature (Tg) Measured at a heating rate of 20 ° C./min using a differential scanning calorimeter (DSC). The sample was used by crimping 5 mg of a sample in an aluminum holding lid type container.

(2) Reduced viscosity 0.01 g of a polyester resin was dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio: 6/4) and measured at 30 ° C.

(3) Density Evaluation Method for Printed Image The image receiving sheet and the thermal transfer sheet are overlapped so that the dyeing layer and the color material layer are in contact with each other, and the output of the head is 0.7 W from the substrate side of the thermal transfer sheet by the thermal head. /Dot,
Heating was performed at a head heating time of 8 mS and a dot density of 3 dots / mm to transfer the cyan dye in the coloring material layer to the dyeing layer.
The obtained transferred image density was measured with a reflection densitometer (DM-600, manufactured by Dainippon Screen Co., Ltd.).

(4) Evaluation method of heat resistance (dark fading rate) The image density of the image receiving body to which the cyan dye was transferred was measured. The image density was measured after being left (aged) for 168 hours in an environment of 60 ° C. in a dark place, and the result was shown by the dye retention (%) in comparison with the density before the heat resistance test.

[0036]

(Equation 1)

(5) Evaluation method of the surface of the printed image area The surface state of the image receiving body onto which the cyan dye has been transferred is observed with a stereoscopic microscope of 40 times magnification. X
The surface state was relatively uniform and the roughness was suppressed, and was evaluated as ○.

(6) Test Method of Plasticizer Resistance A 1-cm ² film of vinyl chloride having a thickness of 50 μm was adhered to the surface of the image receiving body onto which the cyan dye was transferred, and a load of 5 g was applied on the vinyl chloride film. And left in an environment of 40 ° C. for 24 hours. The color loss of the cyan dye and the residue of the film were observed. After aging, ○ indicates that there is no film mark on the surface of the image receiving layer and no change such as color loss, Δ indicates that there is no change in color but film remains, and X indicates that the color has changed and film remains. did.

(7) Test Method for Fingerprint Resistance The thumb was strongly pressed against the surface of the image receiving body to which the cyan dye had been transferred so that the fingerprint remained on the image surface, and was left under an environment of 40 ° C. for 48 hours. Agglomeration, color loss, and fingerprint marks of cyan dye were observed. After aging, ○ indicates no change in the color of the image receiving layer with no trace of fingerprints and no change such as color omission, Δ indicates that there is no change in color but fingerprint trace remains, and X indicates that the color also changes and fingerprint trace remains. did.

(Production Example of Polyester Resin) Dimethyl terephthalate 543 was placed in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
Parts, 232 parts of dimethyl isophthalate, 512 parts of bisphenol A ethylene oxide 2 mol adduct, 509 parts of diethylene glycol, and 0.5 part of tetra-n-butyl titanate, and the transesterification reaction was carried out at 160 to 220 ° C. for 4 hours. And then 25
The temperature was raised to 5 ° C and the pressure of the reaction system was gradually reduced.
The reaction was carried out for 1 hour and 30 minutes under a reduced pressure of mHg to obtain a polyester resin A. The obtained polyester A is pale yellow and transparent,
The reduced viscosity was 0.30 dl / g, and the glass transition temperature was 55 ° C. Table 1 shows polyester resins BE obtained by the same production method. Table 2 shows the evaluation results regarding the above (1) to (7).

Example 1 As a resin for the receiving layer, a polyester resin A was prepared by mixing methyl ethyl ketone / toluene (1:
The mixture was diluted with the mixed solvent of 1) to obtain a 20% solution. Add epoxy-modified silicone oil (Shin-Etsu Chemical:
KF-102) is blended at 10% by weight with respect to the above resin component, and a synthetic paper having a thickness of 150 μm (manufactured by Oji Yuka: Yupo PPG)
-150) using a wire bar so that a dry coating film of 4 μm was obtained. The sheet was dried in an atmosphere at 120 ° C. for 30 minutes to obtain a dyeing layer (dye receiving layer).

(Examples 2 to 4) Polyester resins BD
, A receiver is provided in the same manner as in Example 1,
Examples 2 and 3, respectively.

(Comparative Example 1) An image receiving member was provided in the same manner as in Example 1 using polyester resin E, and Comparative Example 1 was obtained.

(Comparative Examples 2 to 4) Polyester resins F to H
, A receiver is provided in the same manner as in Example 1,
These were Comparative Examples 2 to 4, respectively.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

As described above, the polyester resin composition for a sublimation-type thermal transfer image receptor containing a copolymerized polyester resin as a main component in the present invention has high image sensitivity while maintaining high dyeing sensitivity. The obtained image is excellent in durability and storability, and is industrially useful as a sublimation type thermosensitive recording paper.

Claims (1)

[Claims] 1. A polyester resin composition for a sublimation-type thermal transfer image receptor, comprising a copolymerized polyester resin having a glass transition temperature of 40 ° C. or higher and a reduced viscosity of 0.10 dl / g or higher as a main component. A polyester resin composition for a sublimation-type thermal transfer receiver, wherein at least 10 mol% of the glycol component constituting the polymerized polyester resin is diethylene glycol and at least 20 mol% is a glycol having a cyclic structure.