JP3178554B2 - Aqueous polyester resin composition for image recording media - Google Patents

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 an image recording medium used for obtaining a printed image formed on a film, paper, metal, glass, cloth or the like.

[0002]

2. Description of the Related Art Image recording in the present invention mainly refers to a color hard copy recording system such as a sublimation transfer system, a melt transfer system, an ink jet system, and an electrophotographic system. In these image recordings, a polyester resin comprises a dye and a pigment. It is used beyond the method in terms of dispersibility, dyeing property, affinity and the like. For example, as a dyeing resin used for a dyeing layer of a sublimation transfer image-receiving paper, a conventional dyeing resin is disclosed in
-107885, JP-A-60-64899, JP-A-61-258790, JP-A-62-1
As shown in JP-A-05689, there is known one containing a saturated polyester as a main component.

[0003]

Conventionally, a sublimation transfer method,
When a saturated polyester soluble in an organic solvent is used to obtain a printed image in a melt transfer system, an inkjet system, and an electrophotographic system, a high-quality image with good color density, gradation, color reproducibility, and sharpness can be obtained. Although, fingerprints, oil and fat components represented by various cosmetics, eraser, storage stability of the image due to contamination of the plasticizer component of the vinyl chloride sheet, etc., triggered by the resin attacked by those components, The durability of the obtained printed image is not sufficient, especially in long-term storage, there are problems such as discoloration, image disorder,
It was not at a level that satisfied the required characteristics.

[0004] It is an object of the present invention to provide an organic solvent-resistant, oil- and fat-resistant, fingerprint-resistant and fingerprint-resistant, which causes disturbance of an image formed by a sublimable dye, a pigment ink, a dye ink, a dye toner, a pigment toner and the like. An object of the present invention is to provide an aqueous polyester resin composition exhibiting excellent plasticizer properties.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on an aqueous polyester resin in order to achieve the object of the present invention. As a result, an aqueous polyester resin composition having the following composition was obtained. The inventors have found that the present invention has excellent stability, and have reached the present invention. That is, the present invention provides a glass transition temperature of 4
0 to 70 ° C, resin specific gravity 1.29 or more, SP value 9.5 to 1
2.0, a polyester resin which is insoluble in methyl ethyl ketone, toluene and a mixed solvent thereof, wherein at least 65 mol% of the glycol component of the polyester is ethylene glycol, and which contains at least one kind of hydrophilic polar group An aqueous polyester resin composition for an image recording medium, comprising (A) 5 to 50%, an organic compound (B) 1 to 20% compatible with water, and 30 to 94% of water.

The carboxylic acid component in the polyester of the present invention includes, for example, terephthalic acid, isophthalic acid, orthophthalic acid, 2,3-naphthalic acid, 1,1,3-trimethyl-3-phenylindene-4 ', 5-dicarboxylic acid Acids, such as aromatic dicarboxylic acids, and dicarboxylic acids that can be used other than aromatic dicarboxylic acids include aromatic oxycarboxylic acids such as p- (hydroxyethoxy) benzoic acid;
Aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, unsaturated aliphatic and alicyclic dicarboxylic acids such as fumaric acid, maleic acid, tetrahydrophthalic acid and 1,4-cyclohexanedicarboxylic acid Examples thereof include tri- and tetracarboxylic acids such as acid, trimellitic acid and pyromellitic acid.

[0007] The at least one kind of hydrophilic polar group includes a sulfonic acid metal base, a carboxylic acid metal base, a phosphonic acid metal base, a tertiary amine base or a quaternary amine base, and pyridine. Examples of the sulfonic acid metal base include 5-sodium isophthalic acid, 5-potassium sulfoisophthalic acid, sodium sulfoterephthalic acid,
Tetrabutylphosphonium sulfoisophthalic acid, polycarboxylic acids such as sodium sulfosuccinic acid and derivatives thereof, sodium sulfohydroquinone and alkylene oxide adduct, sodium sulfobisphenol A and alkylene oxide adduct, ethylene oxide adduct of 5-sodium sulfoisophthalic acid, And condensation products of sodium sulfosuccinic acid and ethylene glycol. As the tertiary or quaternary amine, N
And nitrogen-containing alcohols such as -methyldiethanolamine and 2-methyl-2-dimethylaminomethyl-1,3-propanediol, and their hydrochlorides, sulfonates, sulfates, and derivatives thereof. Examples of pyridine include pyridine ring-containing compounds such as dipicolinic acid, dihydroxypyridine, pyridinedimethanol, pyridinepropanediol, and diaminopyridine, and derivatives thereof.

[0008] Examples of the phosphonate metal base include a group having the structure shown in Chemical formula 1 and a group introduced by reacting the compound shown in Chemical formula 2.

[0009]

Embedded image

[0010]

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When no hydrophilic metal base is used,
The dispersibility of the polyester resin in water becomes very poor.

As the glycol component of the polyester resin (A) in the present invention, ethylene glycol accounts for 65 mol% or more of the total glycol component. Glycol components other than ethylene glycol used in less than 35% of the total glycol components include diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexane. Diol, neopentyl glycol, triethylene glycol, dipropylene glycol, 2,2,4-
Examples include trimethyl-1,3-pentanediol, cyclohexane dimethanol, tricyclodecane dimethylol, bisphenol A ethylene oxide and propylene oxide adducts, and hydrogenated bisphenol A ethylene oxide and propylene oxide adducts. 2,2-diethyl-1,3-propanediol,
2-n-butyl-2-ethyl-1,3-propanediol and the like. Of these, neopentyl glycol, ethylene glycol, polyethylene glycol, tricyclodecane dimethylol, and ethylene oxide adduct of bisphenol A are preferred.

[0013] In the polyester resin (A) of the present invention, ethylene glycol in the total glycol component is 6%.
It is essential that the content be 5 mol% or more, and desirably 70 mol% or more. If the content of the glycol is less than 65 mol%, the organic solvent, the plasticizer, and the oil and fat component may be damaged. Therefore, the properties of the obtained image recording, such as the resistance to plasticizers, the resistance to fingerprints, and the resistance to oils and fats, are reduced.

The Tg of the polyester resin (A) is 40 to 7
The temperature is 0 ° C, preferably 50 to 70 ° C. When the Tg is less than 40 ° C., the heat resistance, blocking resistance, etc. of the obtained image are remarkably reduced, and the image is blurred and discolored even at about room temperature, resulting in poor storage stability of the obtained hard copy. Adversely affect. Further, the SP value of the polyester resin (A) is 9.5 to 12.0, preferably 9.8 or more. If it is less than 9.8, the affinity between the plasticizer and the organic solvent having very high affinity is increased, and the durability of the image and the resistance to organic solvents are reduced. Also S
When the P value exceeds 12.0, the affinity for water, alcohol, and the like is increased, and the water resistance and the durability of cosmetics and the like other than the plasticizer are significantly reduced.

The specific gravity of the polyester resin (A) is 1.28.
It is essential that the above is satisfied. If it is less than 1.28, the storability of the recorded image of the image is significantly reduced. Further, by defining the specific gravity of the resin, it is possible to control the ratio of ethylene glycol in all the glycol components contained in the aqueous polyester resin.

"Insoluble in methyl ethyl ketone, toluene, and a mixed solvent thereof" means that it is insoluble in the solvent resistance evaluation method described later. For those solvents and conditions, the polyester resin (A) in the present invention
It is essential that the hard copy itself or the resulting hard copy does not completely dissolve. The poor solubility of the organic solvent is a necessary property for the image stain resistance.

The water-compatible organic compound (B) used in the present invention is specifically one of methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, ter-butanol and the like. Polyhydric alcohols, glycols such as ethylene glycol and propylene glycol, methyl cellosolve, ethyl cellosolve, n-butyl cellosolve, glycol derivatives such as 3-methyl-3-methoxybutanol, ethers such as dioxane, esters such as ethyl acetate, Ketones such as cyclohexanone, cyclooctanone, cyclodecanone, and isophorone; Particularly preferred are n-butyl cellosolve, t-butyl cellosolve, ethyl cellosolve, and isopropanols. These water-compatible organic compounds can be used alone or in combination of two or more. The boiling point of these organic compounds is 60 to 200 ° C.
Must be in the range of When the boiling point does not reach 60 ° C., it is difficult to maintain the temperature required for dissolving the polyester resin in the organic compound. Further, when the boiling point exceeds 200 ° C., it takes time to apply and dry the obtained aqueous dispersion, and the quick-drying property is poor.

In any of the methods, the mixing ratio of the polyester resin (A), the organic compound (B) compatible with water and the water (C) is important for maintaining the performance of the aqueous polyester resin.

When the mixing ratio of the polyester resin (A) contained in the aqueous polyester resin composition does not reach 5% by weight or exceeds 50% by weight, the solution viscosity becomes too low or too high, which is not preferable. When the compounding ratio of the water-compatible organic compound (B) contained in the water-based polyester resin composition is less than 1% by weight, the dispersibility of the polyester resin (A) in water is poor and the water-based polyester resin is stable. If the polyester resin composition is not formed, and the amount of the organic compound (B) exceeds 20% by weight, the drying property is undesirably reduced.

In the present invention, the aqueous polyester resin of the present invention can be mixed and / or reacted with another resin. Examples of the resin to be mixed include a polyvinyl resin, a polycarbonate resin, a polyacrylic resin, a polymethacrylic resin, a polyolefin resin, a cellulose derivative resin, a polyether resin, and a polyester resin.

The water-based polyester resin of the present invention can be thermoset or crosslinked for the purpose of further improving image durability. Examples of the thermosetting resin used in combination with the crosslinking agent include a silicone resin, a melamine resin, a phenol-formaldehyde resin, an epoxy resin, and an isocyanate resin. The crosslinking includes ionic crosslinking, radiation crosslinking and the like.

In the present invention, in addition to the aqueous polyester resin of the present invention, various lubricating substances can be blended for the purpose of improving releasability. As the lubricating substance, a fluorine-based resin, a silicon-based resin, and an organic sulfonate compound,
Interfacial lubricants such as organic phosphate compounds and organic carboxylate compounds are exemplified.

The water-based polyester resin 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. The substrate of the image recording medium is not particularly limited, and examples thereof include paper, synthetic paper, various films, various sheets, metal, and glass.

[0024]

EXAMPLES Hereinafter, the present invention will be described with reference to production examples and examples in order to specifically explain the present invention. In the Production Examples and Examples, “parts” means “parts by weight” and “%” means “% by weight”. The number average molecular weight of the produced polymer was measured by GPC, and the polymer composition was measured by 1 H-NMR. Also,
Glass transition temperature was measured by DSC. These results are shown in Table 1.

Resin specific gravity, SP value, heat resistance, plasticizer resistance,
The measuring method and the calculating method for the fingerprint resistance and the solvent resistance are as shown below, and the evaluation results are shown in Table 2.

(1) Production example of polyester In an autoclave equipped with a thermometer and a stirrer, 233 parts of dimethyl terephthalate and 233 parts of dimethyl isophthalate were added.
Part, 5-sodium sulfoisophthalic acid 30 parts, ethylene glycol 256 parts, diethylene glycol 146
Parts, 0.5 part of tetrabutoxytitanate, 15 parts
The mixture was heated at 0 to 220 ° C. for 240 minutes to perform transesterification, and then the temperature of the reaction system was raised to 250 ° C. in 10 minutes, and the pressure of the system was gradually reduced. After 25 minutes, the pressure was reduced to 0.3 mmHg or less. The reaction was continued for 60 minutes to obtain a pale yellow transparent polyester A. The number average molecular weight of the obtained resin was 20,000. Table 1 shows polyesters BE obtained by the same production method.

(2) Method of Measuring Resin Specific Gravity The specific gravity of the obtained polyester resin was measured by a floating / sedimentation method using a 30 ° C. aqueous solution of calcium chloride. (3) Calculation method of SP value The SP value of the obtained polyester resin was calculated by the method of Small et al. (4) Evaluation method of heat resistance (dark fading rate) The image receiving body to which the cyan dye was transferred was left to stand in a dark place at 60 ° C. for 200 hours, aged, and compared with the density before the heat resistance test. It was shown by the dye concentration retention (%). (5) Evaluation method of plasticizer resistance 80 μm thick on the surface of the image receiving body onto which the cyan dye was transferred.
A 1 cm @ 2 film of vinyl chloride was applied, and a load of 5 g was applied on the vinyl chloride film. The film was allowed to stand at 40 DEG C. for 24 hours to remove the color of cyan dye.
I saw traces of the film. After aging, those having no change such as color omission without a film mark on the image receiving layer surface were evaluated as ○, those with no change in color but film marks remained as Δ, and those with changed color and film marks remained as X. .

(6) Evaluation Method of Fingerprint Resistance The thumb is strongly pressed against the surface of the image receiving body to which the cyan dye has been transferred so that the fingerprint remains on the image surface, and is left under an environment of 40 ° C. for 48 hours. Aggregation, color loss, and fingerprint traces of the cyan dye were observed. After aging, the sample having no color change on the surface of the image receiving layer and having no change in color was evaluated as ○, the sample with no color change but with fingerprint trace remaining was evaluated as △, and the sample in which the dye aggregated on the image surface was evaluated as ×. (7) Method for evaluating solvent resistance The obtained polyester resin was added to a solvent of methyl ethyl ketone, toluene, and methyl ethyl ketone: toluene = 50: 50 so as to have a solid concentration of 15%, and was added at room temperature for 48 hours.
After allowing to stand for a time, the solubility of the resin was visually determined. A system in which the form was not completely dissolved and the shape was maintained was evaluated as ○, and the others were evaluated as ×.

Example 1 30 parts of polyester resin A and n-butyl cellosolve 1
5 parts and stirred in a container at 100 ° C. for about 3 hours,
A homogeneous, viscous melt was obtained. While vigorously stirring the solution, 55 parts of water was added, and after about 1 hour, a uniform pale yellow-white aqueous polyester resin A-1 was obtained. The aqueous polyester resin A-1 for the image receiving layer was treated with isopropanol: water =
Diluted with a 60:40 mixed solution to a thickness of 150 μm
Was coated with a bar coater so that the coating thickness after drying was 7 to 10 μm. This solution was blended with 8% by weight of silicone modified oil based on the above resin. Drying was performed at 100 ° C. for 20 minutes. The adhesion of the obtained film was very good, there was no whitening when immersed in water, and excellent water resistance was exhibited.

Examples 2 to 5 Dyeing layers were provided in the same manner as in Example 1 by using polyesters B to E, and Examples 2 to 5 were obtained.

Comparative Example 1 A dyeing layer was provided in the same manner as in Example 1 using polyester F, and Comparative Example 1 was obtained.

Comparative Examples 2 to 4 Using polyesters G to I, dyeing layers were provided in the same manner as in Example 1 to obtain Comparative Examples 2 to 4.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

EFFECT OF THE INVENTION A polyester resin in which the glycol component of the polyester is 65 mol% or more, has a hydrophilic polar group, and has a glass transition temperature, specific gravity, SP value and solvent solubility in a specific range. When the aqueous polyester resin composition used is used for an image recording layer of an image recording medium, the recorded image shows excellent durability such as heat resistance, plasticizer resistance, index resistance, and solvent resistance.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-238790 (JP, A) JP-A-2-1292992 (JP, A) JP-A-2-196691 (JP, A) JP-A-3- 216384 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/38 B41M 5/00

Claims (1)

(57) [Claims] 1. A glass transition temperature of 40 to 70 ° C. and a specific gravity of 1.
29 or more, SP value of 9.5 to 12.0, insoluble in methyl ethyl ketone, toluene and a mixed solvent thereof, and 65 mol% of the glycol component of the polyester component
The above is ethylene glycol, and a polyester resin (A) containing at least one kind of hydrophilic polar group.
An aqueous polyester resin composition for an image recording medium, comprising 0%, 1 to 20% of an organic compound (B) compatible with water, and 30 to 94% of water (C).