JP2000015936A - Polyester film for sublimation type thermal transfer recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyester film for a sublimation type thermal transfer recording material which is excellent in the adhesion to a sublimation type ink layer. SOLUTION: An adhesion modified layer constituted mainly of a self- crosslinking polyester graft copolymer prepared by grafting hydrophobic polyester resin with a polymerizable unsaturated monomer containing at least one kind of monomer containing an acid anhydride having a double bond is provided at least on one surface of a base film of which the thickness is 1-12 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester film for a sublimation type thermal transfer recording material, and more particularly, to a sublimation type polyester film having an adhesion modifying layer on at least one side thereof and having excellent adhesion to a sublimation type ink layer. An object of the present invention is to provide a polyester film for a thermal transfer recording material.

[0002]

2. Description of the Related Art A thermal transfer recording system is a recording system in which an ink layer provided on the surface of a base film is transferred to the surface of printing paper or the like in accordance with the heating state of a print head. It is becoming widespread from the viewpoint of simplicity and low noise. Among them, the sublimation thermal transfer method transfers solid ink applied to a substrate at room temperature to a photographic paper by heating and vaporizing it with a thermal head. Due to its superiority, demand is growing mainly for video copying such as video printers, digital cameras and digital videos.

On the other hand, polyethylene terephthalate and polyester films typified by polyethylene terephthalate are excellent in many performances such as mechanical strength, heat resistance, dimensional stability and chemical resistance, and are excellent in cost performance. It is also used for sublimation type thermal transfer recording materials. However, in general, since a polyester film has low adhesiveness, in order to enhance the adhesiveness with a sublimation type ink layer, it is common practice to provide a sublimation type ink layer after providing an adhesion modifying layer on the polyester film surface. I have.

[0004] As a method of providing an adhesion-modified layer on the surface of a polyester film, a method of performing application in a polyester film manufacturing process (in-line coating method) is generally used in view of simplification of the process, reduction of manufacturing cost, environmental protection, and the like. Have been done. As a component of the adhesion modifying layer, a water-soluble or water-dispersible polyester resin or acrylic resin (Japanese Patent Application Laid-Open No. 54-43017, Japanese Patent Publication No. 49-10243,
52-19786, JP-A-52-19787, etc.).

However, the above-mentioned polyester resin has a drawback that blocking tends to occur when the film is wound into a roll. In addition, although the adhesion to the polyester film of the base material is relatively good, there is a disadvantage that the adhesion to the sublimation type ink layer is poor. On the other hand, the acrylic resin has better adhesiveness to the sublimation type ink layer than the polyester resin, but has a defect that the adhesiveness to the polyester film as the base material is inferior to the polyester resin. Therefore, for the purpose of improving these drawbacks, it has been proposed to use a mixture of the polyester resin and the acrylic resin (JP-A-58-124651).
No.), but it is hard to say that the improvement of the adhesion defect between the base film and the sublimation type ink layer is sufficient.

Further, it has been proposed to use various modified polyesters mainly for graft modification. For example, JP-A 2-3307, JP-A 2-117243, JP-A 2-3100
No. 48 discloses that a resin obtained by grafting an unsaturated bond-containing compound to a water-soluble or water-dispersible hydrophilic group-containing polyester resin is suitable as a primer for a polyester film. However, in the case of graft modification of a resin in which a hydrophilic group is previously contained in a polyester resin by copolymerization or the like, adhesiveness is not sufficient.

Also, Japanese Patent Application Laid-Open No. 3-273015, Japanese Patent Publication No. 3-67626
Also discloses that graft modified resins of polyester are useful as primers for polyester films. However, at present, these resins also have problems such as peeling of the film and scratching due to poor cohesive force.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyester film for a sublimation type thermal transfer recording material having excellent adhesion to a sublimation type ink layer.

[0009]

According to the present invention, there is provided a method for manufacturing a semiconductor device, comprising:
Self-crosslinkable polyester graft in which a polymerizable unsaturated monomer containing at least one monomer containing an acid anhydride having a double bond in a hydrophobic polyester resin is grafted on at least one surface of a 2 μm base film. The above object can be attained by a polyester film for a sublimation type thermal transfer recording material, characterized by having an adhesion modified layer containing a copolymer as a main component.

[0010] In a preferred embodiment of the present invention, a coating solution containing the self-crosslinkable polyester-based graft copolymer and a crosslinking agent is applied to an unstretched or uniaxially stretched film, and the coated film is dried. Is a polyester film for a sublimation-type thermal transfer recording material formed by uniaxially or more stretching and heat fixing.

In a further preferred embodiment of the present invention, the base film has a birefringence of 0.035 to 0.060,
In addition, the polymerizable unsaturated monomer according to claim 1 contains at least maleic anhydride and styrene.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The term "grafting" of a self-crosslinkable polyester-based graft copolymer in the present invention refers to the introduction of a branch polymer composed of a polymer different from the main chain into the main chain of the main polymer. .

The graft polymerization of the present invention is generally carried out by reacting a radical initiator and a radical polymerizable monomer mixture in a state where a hydrophobic copolymerized polyester resin is dissolved in an organic solvent. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

In the present invention, the acid value of a reaction product obtained by graft-polymerizing a radically polymerizable monomer onto a hydrophobic copolymerized polyester resin is preferably at least 600 eq / ton. More preferably, the acid value of the reactants is 1200 eq /
ton or more. The reaction product has an acid value of 600 eq / ton
If it is less than 1, the adhesiveness between the base polyester film and the sublimation type ink layer, which is the object of the present invention, cannot be said to be sufficient.

Further, the weight ratio of the hydrophobic copolymerizable polyester resin and the radical polymerizable monomer suitable for the purpose of the present invention is as follows: polyester / radical polymerizable monomer = 4
The range is preferably 0/60 to 95/5, more preferably 55/45 to 93/7, most preferably 60/40 to 9/9.
It is in the range of 0/10. When the weight ratio of the hydrophobic copolymerized polyester resin is less than 40% by weight, excellent adhesiveness of the polyester resin cannot be exhibited. on the other hand,
95% by weight of hydrophobic copolymerized polyester resin
When it is larger, blocking, which is a drawback of the polyester resin, tends to occur.

The graft polymerization product of the present invention takes the form of a solution or dispersion of an organic solvent or a solution or dispersion of an aqueous solvent. In particular, the form of the water-dispersed resin is preferable in view of the working environment and applicability. In order to obtain such a water-dispersed resin, usually, in an organic solvent, the hydrophobic copolymerized polyester resin is graft-polymerized with a radical polymerizable monomer containing a hydrophilic radical polymerizable monomer, Water addition,
Achieved by evaporation of the organic solvent.

In the present invention, the hydrophilic radically polymerizable monomer used for the polymerization of the water-dispersed resin refers to a group having a hydrophilic group or a group which can be converted into a hydrophilic group later. As a radical polymerizable monomer having a hydrophilic group, a carboxyl group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, an amide group,
A radical polymerizable monomer containing a quaternary ammonium base or the like can be given. On the other hand, as radical polymerizable monomers that can be converted to hydrophilic groups, acid anhydride groups, glycidyl groups,
Chlorine and the like can be mentioned. Among these, a carboxyl group is preferable from the viewpoint of water dispersibility, and a radical polymerizable monomer having a carboxyl group or a group generating a carboxyl group is preferable. From the viewpoint of increasing the acid value of the present invention, it is preferable that the compound contains a carboxyl group or contains a radical polymerizable monomer that generates a carboxyl group.

The glass transition temperature of the graft copolymer is not particularly limited, but is preferably 30 ° C. or lower. By using a graft copolymer having a glass transition temperature of 30 ° C. or lower for the adhesion modifying layer, a polyester film having particularly excellent adhesion to the sublimation type ink layer can be obtained.

In the present invention, the hydrophobic copolyester resin must be essentially water-insoluble and does not originally disperse or dissolve in water. When a polyester resin that is dispersed or dissolved in water is used for graft polymerization, the adhesiveness, which is the object of the present invention, is deteriorated.

The composition of the dicarboxylic acid component of the hydrophobic copolymerized polyester resin is from 60 to 9 aromatic dicarboxylic acids.
It is preferably 9.5 mol%, 0 to 40 mol% of aliphatic dicarboxylic acid and / or alicyclic dicarboxylic acid, and 0.5 to 10 mol% of dicarboxylic acid containing a polymerizable unsaturated double bond. When the amount of the aromatic dicarboxylic acid is less than 60% by mole or when the amount of the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid exceeds 40% by mole, the adhesive strength decreases.

When the amount of the dicarboxylic acid having a polymerizable unsaturated double bond is less than 0.5 mol%, it is difficult to efficiently graft the radical polymerizable monomer to the polyester resin. If it exceeds 10 mol%,
It is not preferable because the viscosity increases too late in the late stage of the grafting reaction, which hinders the uniform progress of the reaction. More preferably, the aromatic dicarboxylic acid is 70-98 mol%, the aliphatic dicarboxylic acid and / or the alicyclic dicarboxylic acid is 0-30 mol%.
Mol%, 2 to 7 mol% of a dicarboxylic acid containing a polymerizable unsaturated double bond.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid and the like. It is preferable not to use a hydrophilic group-containing dicarboxylic acid such as 5-sodium sulfoisophthalic acid from the viewpoint of reducing the water resistance, which is the object of the present invention. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecandionic acid, and dimer acid.Examples of the alicyclic dicarboxylic acid include 1,4-cyclohexanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid. Examples thereof include 3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and acid anhydrides thereof.

Examples of dicarboxylic acids containing a polymerizable unsaturated double bond include α, β-unsaturated dicarboxylic acids such as fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, and unsaturated double acids. Examples of the alicyclic dicarboxylic acid having a bond include 2,5-norbornene dicarboxylic anhydride, tetrahydrophthalic anhydride and the like. Of these, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred from the viewpoint of polymerizability.

On the other hand, the glycol component has 2 to 10 carbon atoms.
And / or an alicyclic glycol having 6 to 12 carbon atoms and / or an ether bond-containing glycol. Examples of the aliphatic glycol having 2 to 10 carbon atoms include 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-2-butylpropanediol and the like can be mentioned, and as the alicyclic glycol having 6 to 12 carbon atoms,
1,4-cyclohexanedimethanol and the like can be mentioned.

Examples of the glycol containing an ether bond include diethylene glycol, triethylene glycol, dipropylene glycol, and glycols obtained by adding ethylene oxide or propylene oxide to two phenolic hydroxyl groups of bisphenols, such as 2,2-glycol. Bis (4-hydroxyethoxyphenyl) propane and the like can be mentioned. Polyethylene glycol, polypropylene glycol and polytetramethylene glycol can also be used if necessary.

In the copolymerized polyester resin used in the present invention, 0 to 5 mol% of trifunctional or higher polycarboxylic acid and / or polyol can be copolymerized.
Examples of trifunctional or higher polycarboxylic acids include (anhydride) trimellitic acid, (anhydrous) pyromellitic acid, (anhydrous) benzophenonetetracarboxylic acid, trimesic acid, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydride) Hydrotrimellitate) and the like are used. On the other hand, as trifunctional or higher polyols, glycerin, trimethylolethane, trimethylolpropane,
Pentaerythritol and the like are used. The trifunctional or higher polycarboxylic acid and / or polyol is copolymerized in the range of 0 to 5 mol%, preferably 0 to 3 mol%, based on the total acid component or total glycol component. Gelation at the time of polymerization tends to occur, which is not preferable.

The molecular weight of the hydrophobic copolyester resin is preferably in the range of 5,000 to 50,000 on the weight average. When the molecular weight is less than 5,000, the adhesive strength is reduced, while when it exceeds 50,000, problems such as gelation during polymerization occur.

Examples of the polymerizable unsaturated monomer of the present invention include monoesters or diesters of fumaric acid such as fumaric acid, monoethyl fumarate, diethyl fumarate and dibutyl fumarate maleic acid and its anhydride, monoethyl maleate, Monoesters or diesters of maleic acid such as diethyl maleate and dibutyl maleate; itaconic acid and its anhydride; monoesters or diesters of itaconic acid; maleimides such as phenylmaleimide; and styrene, α-methylstyrene, t-butyl Examples thereof include styrene derivatives such as styrene and chloromethylstyrene, vinyltoluene, divinylbenzene, and the like.

Examples of the acrylic polymerizable monomers include alkyl acrylates and alkyl methacrylates (the alkyl groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl,
2-ethylhexyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.): hydroxy-containing acrylic monomer of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate : Acrylamide, methacrylamide, N-
Methyl methacrylamide, N-methylacrylamide,
N-methylol acrylamide, N-methylol methacrylamide, N, N-dimethylol acrylamide, N
Amide group-containing acrylic monomers of -methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide: N, N-diethylaminoethyl acrylate, amino group-containing acrylic monomers of N, N-diethylaminoethyl methacrylate: glycidyl Acrylic and glycidyl methacrylate epoxy group-containing acrylic monomers: acrylic acid, methacrylic acid and their salts (sodium salt, potassium salt, ammonium salt)
And acrylic monomers containing a carboxyl group or a salt thereof. Preferred are maleic anhydride and its esters. The above monomers can be copolymerized by using one kind or two or more kinds.

The graft polymerization of the present invention is generally carried out by reacting a radical initiator and a radical polymerizable monomer mixture in a state where a hydrophobic copolymerized polyester resin is dissolved in an organic solvent. The reaction product after the completion of the grafting reaction is, in addition to the graft polymer between the desired hydrophobic copolymerized polyester-radical polymerizable monomer mixture, the hydrophobic copolymerized polyester that has not been grafted and the hydrophobic copolymerized polyester. It also contains a radical polymer not grafted to the polymerized polyester, but the graft polymer in the present invention includes all of them.

As the graft polymerization initiator that can be used in the present invention, organic peroxides and organic azo compounds known to those skilled in the art can be used. Benzoyl peroxide and t-butyl peroxypivalate as organic peroxides and 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylparero) as organic azo compounds Nitrile) and the like. The amount of the polymerization initiator used for performing the graft polymerization is at least 0.2% by weight or more, preferably 0.5% by weight or more based on the polymerizable monomer.

In addition to the polymerization initiator, a chain transfer agent for adjusting the chain length of the branched polymer, for example, octyl mercaptan, mercaptoethanol, 3-t-butyl-4-hydroxyanisole, etc. can be used as required. In this case, it is desirable to add in the range of 0 to 5% by weight based on the polymerizable monomer.

The grafting reaction solvent used in the present invention is preferably composed of an aqueous organic solvent having a boiling point of 50 to 250 ° C. Here, the aqueous organic solvent means a solvent having a solubility in water at 20 ° C. of at least 10 g / L, desirably 20 g / L or more. Boiling point is 25
Those exceeding 0 ° C. are unsuitable because the evaporation rate is too slow and the coating film cannot be sufficiently removed even by high-temperature treatment. When the boiling point is 50 ° C. or lower, when a grafting reaction is carried out using the solvent as a solvent, an initiator that cleaves into radicals at a temperature of 50 ° C. or lower must be used.

The first group of aqueous organic solvents which dissolves the copolymerized polyester resin well and dissolves the polymerizable monomer mixture containing the carboxyl group-containing polymerizable monomer and its polymer relatively well is an ester. (For example, ethyl acetate), ketones (for example, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), cyclic ethers (for example, tetrahydrofuran, dioxane, 1,3-dioxolane), and glycol ethers (for example, Ethylene glycol dimethyl ether, propylene glycol methyl ether, propylene glycol propyl ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, carbitols (eg, methyl carbitol, ethyl carbitol, butyl carbitol), Glyco- And lower esters of glycol ethers (eg, ethylene glycol diacetate, ethylene glycol ethyl ether acetate), ketone alcohols (eg, diacetone alcohol), and N-substituted amides (eg, Dimethylformamide, dimethylacetamide, N-methylpyrrolidone) and the like.

On the other hand, as a second group of aqueous organic solvents, which hardly dissolve the copolymerized polyester resin but contain the carboxyl group-containing polymerizable monomer and dissolve the polymer relatively well, , Water, lower alcohols, lower carboxylic acids, lower amines, etc., and particularly preferable for the practice of the present invention are alcohols and glycols having 1 to 4 carbon atoms.

When the grafting reaction is carried out with a single solvent, it can be carried out by selecting only one kind from the first group of aqueous organic solvents. When using a mixed solvent, there are a case where a plurality of types are selected only from the first group of aqueous organic solvents, and a case where at least one type is selected from the first group of aqueous organic solvents and at least one type is added from the second group of aqueous organic solvents.

In both cases where the graft polymerization reaction solvent is a single solvent from the first group of aqueous organic solvents, and when it is a mixed solvent composed of one kind of each of the first and second groups of aqueous organic solvents. A graft polymerization reaction can be performed. However, there are differences in the progress of the grafting reaction, the appearance and properties of the grafting reaction product and the aqueous dispersion derived therefrom, and a mixed solvent composed of one of the first and second groups of aqueous organic solvents, respectively. It is preferable to use

In the first group of solvents, the copolyester molecular chains are in the state of extended broad chains, while in the mixed solvent of the first group / second group, they are entangled in a narrowly spread thread. The state was confirmed by measuring the viscosity of the copolymerized polyester in these solutions. It is effective to prevent gelation by adjusting the dissolution state of the copolymerized polyester so as to prevent intermolecular crosslinking. Both high efficiency of grafting and suppression of gelation are achieved in the latter mixed solvent system. The weight ratio of the mixed solvent of the first group / second group is more preferably from 95/5 to 10/90, further preferably 90/1.
0-20 / 80, most preferably 85 / 15-30 / 7
It is in the range of 0. The optimum mixing ratio is determined according to the solubility of the polyester used.

The grafting reaction product according to the present invention is preferably neutralized with a basic compound, and can be easily dispersed in water by neutralization. As the basic compound, a compound which volatilizes at the time of forming a coating film or at the time of baking and curing with a curing agent is desirable, and ammonia, organic amines and the like are preferable. Examples of preferred compounds include triethylamine, N, N-diethylethanolamine, N, N-dimethylethanolamine, aminoethanolamine, N-methyl-N, N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, Diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, dimethylaminopropylamine, methyliminobispropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine Examples include ethanolamine. The basic compound has a pH value of the aqueous dispersion in the range of 5.0 to 9.0 by at least partial neutralization or complete neutralization depending on the carboxyl group content contained in the grafting reaction product. Preferably, it is used as follows.

In the aqueous dispersion produced according to the present invention,
The weight average molecular weight of the polymer of the radical polymerizable monomer is 50.
It is preferably from 0 to 50,000. It is generally difficult to control the weight-average molecular weight of the polymer of the radical polymerizable monomer to 500 or less, the graft efficiency is reduced, and the hydrophilic group tends not to be sufficiently imparted to the copolymerized polyester. is there. Further, the graft polymer of the radical polymerizable monomer forms a hydrated layer of the dispersed particles, but in order to provide a hydrated layer having a sufficient thickness and obtain a stable dispersion, The weight average molecular weight of the graft polymer is desirably 500 or more. The upper limit of the weight average molecular weight is 500 in terms of polymerizability in solution polymerization.
00 is preferred. Control of the molecular weight within this range is the initiator amount, monomer dropping time, polymerization time, reaction solvent,
It can be carried out by appropriately combining a monomer composition or, if necessary, a chain transfer agent and a polymerization inhibitor.

In the present invention, a reaction product obtained by graft-polymerizing a radically polymerizable monomer onto a hydrophobic copolymerized polyester resin has a self-crosslinking property. Does not crosslink at room temperature,
With the heat during drying, an intermolecular reaction such as a hydrogen abstraction reaction by a thermal radical is performed, and crosslinking is performed without a crosslinking agent. Thereby, the adhesiveness which is the object of the present invention can be expressed for the first time. The crosslinkability of the coating film can be evaluated by various methods, but can be evaluated by the insoluble content in a chloroform solvent that dissolves both the hydrophobic copolymerized polyester resin and the radical polymer. The coating film obtained by drying at 80 ° C. or lower and heat-treating at 120 ° C. for 5 minutes has an insoluble content of preferably 50%
It is more preferably 70% or more. When the insoluble content of the coating film is less than 50%, not only the adhesion is not sufficient, but also blocking occurs.

In the present invention, it is possible to impart high adhesiveness and solvent resistance by adding a crosslinking agent. As the cross-linking agent, a cross-linking reaction is caused by heat or light with a functional group or the like present in the self-cross-linkable polyester-based graft copolymer onto which the polymerizable unsaturated monomer is grafted. It can form a structure, and is not particularly limited.

Examples of the crosslinking agent include phenol-formaldehyde resins which are condensates with formaldehyde such as alkylated phenols and cresols; urea, melamine,
Adducts of benzoguanamine and the like with formaldehyde,
An amino resin such as an alkyl ether compound comprising the adduct and an alcohol having 1 to 6 carbon atoms; a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a blocked isocyanate compound; a polyfunctional aziridine compound;
Oxazoline compounds and the like can be used.

Examples of the phenol formaldehyde resin include alkylated (methyl, ethyl, propyl,
Isopropyl or butyl) phenol, p-tert
-Amylphenol, 4,4'-sec-butylidenephenol, p-tert-butylphenol, o-, m
-, P-cresol, p-cyclohexylphenol,
4,4′-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-pentadecylphenol, phenol, phenyl o-cresol, p
-Condensates of phenols such as phenylphenol and xylenol with formaldehyde.

Examples of the amino resin include methoxylated methylol urea, methoxylated methylol N, N-ethylene urea, methoxylated methylol dicyandiamide, methoxylated methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, and butoxylated methylol benzoguanamine. And methoxylated methylolmelamine, butoxylated methylolmelamine, and methylolated benzoguanamine.

Examples of the polyfunctional epoxy compound include diglycidyl ether of bisphenol A and oligomers thereof, diglycidyl ether of hydrogenated bisphenol A and oligomers thereof, diglycidyl orthophthalate, diglycidyl isophthalate, and the like.
Diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene Glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ethers, trimellitic acid triglycidyl ester, triglycidyl isocyanurate ,
1,4-diglycidyloxybenzene, diglycidylpropylene urea, glycerol triglycidyl ether,
Examples include trimethylolpropane triglycidyl ether, pentaerythritol triglycidyl ether, and triglycidyl ether of a glycerol alkylene oxide adduct.

As the polyfunctional isocyanate compound,
Low-molecular or high-molecular aromatic or aliphatic diisocyanates and trivalent or higher polyisocyanates can be used. Examples of the polyisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. Further, an excess amount of these isocyanate compounds and a low-molecular active hydrogen compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or polyester polyols, Examples thereof include a terminal isocyanate group-containing compound obtained by reacting a polymer active hydrogen compound such as ether polyols and polyamides.

The blocked isocyanate can be prepared by subjecting the isocyanate compound and a blocking agent to an addition reaction by a conventionally known appropriate method. Examples of the isocyanate blocking agent include phenols such as phenol, cresol, xylenol, resorcinol, nitrophenol, and chlorophenol; thiophenols such as thiophenol and methylthiophenol; oximes such as acetoxime, methyl etiketoxime, and cyclohexanone oxime. Alcohols such as methanol, ethanol, propanol and butanol; halogen-substituted alcohols such as ethylene chlorohydrin and 1,3-dichloro-2-propanol; t-butanol and t-
Tertiary alcohols such as pentanol; ε-caprolactam, δ-valerolactam, ν-butyrolactam, β
Lactams such as propyl lactam; aromatic amines; imides; active methylene compounds such as acetylacetone, acetoacetate ester, and malonic acid ethyl ester; mercaptans; imines; ureas; diaryl compounds; Can be mentioned.

These crosslinker bonds can be used alone or in combination of two or more. The compounding amount of the crosslinking agent is 1 part by weight to 4 parts by weight based on 100 parts by weight of the grafted copolymer.
0 parts by weight is preferred. As a method of compounding the crosslinking agent,
(1) When the crosslinking agent is water-soluble, a method of dissolving or dispersing it directly in an aqueous solvent solution or dispersion of the graft copolymer, or (2) When the crosslinking agent is oil-soluble, after completion of the grafting reaction And a method of adding to a reaction solution. These methods can be appropriately selected depending on the type and properties of the crosslinking agent. Further, a curing agent or an accelerator can be used in combination with the crosslinking agent.

The adhesion modifying layer may further contain various surfactants, antistatic agents, inorganic lubricants, organic lubricants and other additives as long as the effects of the present invention are not impaired.

As the coating solution, an organic solvent solution or dispersion of the self-crosslinkable polyester-based graft copolymer constituting the adhesion modifying layer, or an aqueous solvent solution or aqueous solvent dispersion can be used. In particular, an aqueous solution or dispersion is preferable in that an organic solvent which is problematic for the environment is not used. The solid content of the self-crosslinkable polyester-based graft copolymer and the crosslinking agent in an organic solvent or an aqueous solvent is usually 1% by weight to 50% by weight, preferably 3% by weight to 30% by weight.

There are no particular restrictions on the drying conditions for the graft copolymer after coating. However, in order to exhibit the self-crosslinking property of the graft copolymer, thermal degradation of the base film and the graft copolymer is required. As long as it does not occur, a condition for increasing the amount of heat is preferable. Specifically, the temperature is from 80C to 250C, more preferably from 150C to 220C. However, by extending the drying time, sufficient self-crosslinking property is exhibited even at a relatively low temperature, so that the conditions are not limited to the above.

As a method for applying a coating solution containing a self-crosslinkable polyester-based graft copolymer to a thermoplastic film substrate to form an adhesion-modified layer, a gravure method, a reverse method, a die method, a bar method A known coating method such as a dip method can be used.

The coating amount of the coating solution is 0.00
5~5g / m ^2, preferably, 0.02 to 0.5 g / m
² When the coating amount becomes 0.005 g / m ² or less,
Sufficient adhesive strength with the adhesion modified layer cannot be obtained. 5g / m
^If it is more than ² , blocking occurs, and there is a practical problem.

The adhesion-modified layer may be formed by coating the above-mentioned coating solution on a thermoplastic film substrate after biaxial stretching, or by coating the above coating solution on unstretched or uniaxially stretched thermoplastic film substrate. After the drying, the film may be dried, and if necessary, may be further subjected to heat setting after uniaxial stretching or biaxial stretching. At this time, if the heat setting temperature is set to 200 ° C. or higher, the coating film becomes strong and the adhesiveness is further improved.

The polyester constituting the polyester film for a sublimation type thermal transfer recording material of the present invention is not particularly limited, but polyethylene terephthalate, polyethylene-2,6-naphthalate, and polybutylene terephthalate are preferable, and the quality, economy, etc. From the viewpoint of, polyethylene terephthalate is particularly preferable among these.

In the above polyethylene terephthalate, the monomer unit of ethylene terephthalate therein is usually 8
It is 0 mol% or more, preferably 90 mol% or more, and other dicarboxylic acid components and diol components may be copolymerized within the above-mentioned range. Known additives such as a heat-resistant stabilizer, an oxidation-resistant stabilizer, a weather-resistant stabilizer, and an ultraviolet absorber may be added as long as the effects of the present invention are not impaired. In the polyethylene terephthalate film of the base material, an average particle size is 0.1
It is necessary to contain 0.01 to 1.0% by weight of one or more kinds of inorganic or organic inert particles having a particle size of ３3 μm. The average particle size of the inert particles is as follows: in the case of silica, in a mixed solution of ethylene glycol / water = 10/90 (volume ratio), and in the case of other types of particles, in ethylene glycol. It measured using the formula particle size distribution analyzer SA-CP2.

The intrinsic viscosity of the above polyethylene terephthalate film is 0.52 to 0.62 dl / g. If the intrinsic viscosity is less than 0.52 dl / g, breakage tends to occur during film production. On the other hand, the intrinsic viscosity is 0.6
If it is more than 2 dl / g, when slitting to a predetermined product width, burrs are likely to occur, which is not preferable.

The base polyester film in the present invention needs to have a thickness of 1 to 12 μm. Preferably it is 2 to 7 μm. Base film thickness is 1μm
If the thickness is smaller than that, it is not preferable because plastic deformation occurs at the time of use, resulting in a rough winding. On the other hand, when the thickness of the base film is 12
When the thickness is larger than μm, heat conduction is poor and the printing state is deteriorated, which is not preferable.

When the birefringence of the base polyester film is 0.035 to 0.060, not only is the slit property in the longitudinal direction improved, but also the adhesive property between the base polyester film and the adhesion modifying layer is improved. Can be further improved. When the birefringence is less than 0.035, the slitting property in the longitudinal direction is deteriorated, and the swarf when slitting adheres to the adhesion modified surface, so that the adhesion between the base polyester film and the adhesion modified layer is deteriorated. I do. Further, chips tend to be generated when slitting, and the chips fall off while the birefringence is 0.1.
A polyester film having a ratio of more than 06 has a large heat shrinkage in the longitudinal direction, and is likely to be wrinkled when the sublimation type ink layer is applied and dried.

A typical method for obtaining the polyester film of the present invention having the above characteristics and provided with an adhesion modifying layer will be described below. As a first method, a coating solution is applied to at least one surface of an unstretched polyester film, and then continuously led to a preheating zone of about 70 to 110 ° C., and stretched in a horizontal or vertical order in a drying or drying process. Temperature 80 ~ 110
At a temperature of 3.4 to 5 times, and then 200 to 240 times.
After heat-setting at 0 ° C, 0.1-5
% Relaxation treatment.

As a second method, the film is stretched longitudinally and uniaxially at the above-mentioned stretching temperature and magnification, and the above-mentioned coating solution is applied to a polyester film, and then guided to a drying zone at about 90 to 110 ° C.
After being stretched in the horizontal direction at the above stretching temperature and magnification in the state of drying or drying, 100 to 130 ° C in the vertical direction again
Stretched 1.01 to 1.2 times, and then 200 to 240 ° C.
And heat fixing. The relaxation process is performed under the conditions described in the first method.

In order to further improve the adhesiveness between the polyester film substrate and the adhesion modifying layer, before providing the adhesion modifying layer, the polyester film substrate is subjected to surface treatment such as corona treatment, flame treatment and electron beam irradiation. You may do.

The adhesion-modified layer of the polyester film substrate for a sublimation-type thermal transfer recording material of the present invention has good adhesion to the sublimation-type ink layer. Further, surface treatment such as corona treatment, flame treatment, and electron beam irradiation may be performed.

The polyester film for a sublimation type thermal transfer recording material of the present invention can be suitably used as a sublimation type thermal transfer recording material by laminating a sublimation type ink layer on the adhesion modifying layer side of a base film. As the sublimation type ink layer, for example, a material in which a known sublimation solid dye such as yellow, magenta, and cyan is dispersed in a binder such as polyvinyl butyral and an organic solvent is applied.

[0066]

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”. Each measurement item followed the following method.

(1) Intrinsic Viscosity of Polyester A sample was vacuum-dried at 70 ° C. all day and night, and 80 mg was precisely weighed.
A mixed solution of phenol / tetrachloroethane = 60/40 (volume ratio) was heated and dissolved. 20 mL with the mixed solution
, And measured at 30 ° C.

(2) Birefringence (ΔN) Using an Abbe refractometer manufactured by Atago Optical Co., the longitudinal refractive index (Nx) and the lateral refractive index (Ny) of the film were each 3
The measurement was repeated twice and the average value was determined. The birefringence (ΔN) was calculated by the following equation. ΔN = Nx−Ny

(3) Adhesiveness to sublimation type ink layer (Method of preparing sublimation type ink) Cyan sublimation dye (CY6, manufactured by Nippon Kayaku Co., Ltd.): 3 parts Polyvinyl butyral resin (BX-1, Sekisui Chemical Co., Ltd.) Manufacture): 4.5 parts Methyl ethyl ketone: 46.25 parts Toluene: 46.25 parts The mixture having the above composition was mixed with glass beads for 30 minutes using a paint shaker to prepare a sublimation ink. (Preparation of Sublimation-Type Ink Layer) After applying the sublimation-type ink to the adhesion-modified layer side of the polyester films obtained in Examples and Comparative Examples of the present invention, the resultant was dried at 100 ° C. for 90 seconds to form a 2 μm thick layer. A sublimation type ink layer was provided. (Evaluation of Adhesiveness) A double-sided adhesive tape (3M Scotch # 666)) was attached to a 0.7 mm-thick stainless steel plate, and further cut into 12.5 mm width so that the sublimation type ink layer surface was in contact with the double-sided adhesive tape. The polyester film coated with the sublimation type ink layer is bonded. After rubbing three times with a rubber roller, peeling was performed at a speed of 500 mm / min and an angle of 180 ° using a tensile tester. At this time, the stainless plate was sandwiched between the lower chucks, and the non-adhered portion of the polyester film coated with the sublimation type ink layer with the double-sided adhesive tape was sandwiched between the upper chucks. The adhesiveness between the sublimation type ink layer and the base polyester film was visually determined according to the following criteria based on the degree of peeling of the ink layer. All the above operations were performed in a constant temperature and humidity room at 23 ° C. and 65% RH. ◎: No peeling of the ink layer was observed at all. ：: Peeling of the ink layer was slightly observed (practically usable). Δ: Peeling of the ink layer was partially observed. Be

(4) A glass transition temperature (Tg) solution or dispersion of the self-crosslinkable polyester-based graft copolymer was applied to a glass plate, and then dried at 170 ° C. to obtain a graft copolymer solid. Tg was measured by taking 10 mg of this solid content in a sample pan and scanning at a rate of 10 ° C./min with a differential scanning calorimeter.

(5) Evaluation of slitting property After the sublimation type ink layer described in “(3) Adhesion with sublimation type ink layer” was provided on the polyester film, then 12.
The slit was slit to 1000 mm in a width of 5 mm, and the slit surface was observed with an optical microscope (400 times). ：: Very small amount of swarf falling ○: Little swarf spilling (practically usable) △: Many swarf swarf ×: Very large swarf spilling

[0072]

Example 1 (Preparation of copolymerized polyester) Dimethyl terephthalate 3 was placed in a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser.
45 parts, 211 parts of 1,4 butanediol, 270 parts of ethylene glycol, and 0.5 part of tetra-n-butyl titanate were charged, and a transesterification reaction was performed from 160 ° C. to 220 ° C. for 4 hours. Then, fumaric acid 1
Add 4 parts and 160 parts of sebacic acid, and
The temperature was raised to 20 ° C. over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., and the pressure in the reaction system was gradually reduced. Then, the reaction was carried out under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a copolymerized polyester. The obtained polyester had a weight average molecular weight of 20,000 and was light yellow and transparent.

(Preparation of Self-Crosslinkable Polyester-Based Graft Copolymer) Into a reactor equipped with a stirrer, a thermometer, a reflux device and a metering dropping device, the above-mentioned copolymerized polyester resin 75
, 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol, and heated and stirred at 65 ° C. to dissolve the resin. After the resin was completely dissolved, 15 parts of maleic anhydride was added to the polyester solution. Then, 10 parts of styrene,
And 1.5 parts of azobisdimethylvaleronitrile in 12 parts
Of the solution dissolved in 0.1 part of methyl ethyl ketone
Minutes, the mixture was dropped into the polyester solution, and the stirring was continued for another 2 hours. After sampling for analysis from the reaction solution, 5 parts of methanol was added. Next, 300 parts of water and 15 parts of triethylamine were added to the reaction solution, followed by stirring for 1 hour. Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off to obtain a water-dispersed graft polymerization resin. The water-dispersed graft resin was pale yellow and transparent, and had a glass transition temperature of -10 ° C.

(Preparation of Coating Solution for Adhesion Modified Layer) The coating solution was prepared by diluting the water-dispersed graft resin with water / isopropyl alcohol = 90/10 (weight ratio) so that the solid content concentration became 10%.

(Production of a polyester film provided with an adhesion-modifying layer)
17% by weight of kaolin having an average particle diameter of 0.80 μm was added to 0.1% of kaolin.
And containing 0.05% by weight of synthetic calcium carbonate having an average particle diameter of 1.05 μm and an intrinsic viscosity of 0.57%.
Was dried and extruded at 285 ° C., and cooled and adhered to a casting drum by an electrostatic adhesion method to obtain an unstretched polyethylene terephthalate film having an intrinsic viscosity of 0.55. The coating liquid is applied to the unstretched film by a roll coater method and dried with hot air at 100 ° C. in a preheating zone of a tenter, and then 3.88 times in the horizontal direction at 92 ° C. and 3.64 times in the vertical direction at 81 ° C. Stretched. Then in the heat set zone at 226 ° C. for 1.0
After re-stretching 5 times, it was heat-treated at 228 ° C. 2 more
Relaxation heat treatment was performed in the transverse direction at 2.6% at 10 ° C. and 0.3% at 150 ° C. to obtain a 6 μm-thick biaxially stretched polyethylene terephthalate film provided with an adhesion modifying layer. The final coating agent application amount was 0.05 g / m ² .

[0076]

Example 2 The above-mentioned coating solution was applied to an unstretched polyethylene terephthalate film obtained in the same manner as in Example 1 by a roll coater method and dried with hot air at 100 ° C. in a preheating zone of a tenter. Then, at 92 ° C., 3.92 laterally
The film was stretched 4.02 times at 82 ° C. in the machine direction. Next, in the heat setting zone, the sheet was re-stretched 1.05 times at 200 ° C, and then heat-treated at 210 ° C. 1.5 ° C at 210 ° C
And a 1.6% transverse relaxation heat treatment at 150 ° C. to obtain a 6 μm-thick biaxially stretched polyethylene terephthalate film provided with an adhesion modifying layer. The final coating agent application amount was 0.05 g / m ² .

[0077]

Example 3 An undrawn polyethylene terephthalate film was obtained in the same manner as in Example 1. Next, the unstretched film was stretched 3.7 times in the longitudinal direction at 83 ° C., and the coating solution described in Example 1 was applied to one surface of the obtained film by a roll coater method.
It dried with the hot air of ° C. Next, the above coating film was
Stretched 3.6 times at 150 ° C., and then 115 ° C. again in the longitudinal direction.
After stretching by 1.20 times, heat treatment is performed at 220 ° C., and further, 2.6% at 210 ° C. and 0.3% at 150 ° C. are relaxed and heat-treated in the transverse direction to form a 6 μm-thick layer having an adhesion-modified layer. The biaxially stretched polyethylene terephthalate film was obtained. The final coating agent application amount was 0.05 g / m ² .

[0078]

Example 4 75 parts of the above-mentioned copolymerized polyester resin was placed in a reactor equipped with a stirrer, a thermometer, a reflux device, and a metered addition device.
56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were added, and the mixture was heated and stirred at 65 ° C. to dissolve the resin. After the resin was completely dissolved, 15 parts of maleic anhydride was added to the polyester solution. Next, a solution of 10 parts of styrene and 1.5 parts of azobisdimethylvaleronitrile dissolved in 12 parts of methyl ethyl ketone was dropped into the polyester solution at 0.1 ml / min. After dropping, stirring was further continued for 2 hours to obtain a solvent type graft polymerization resin. The glass transition temperature of the obtained solvent-type graft polymerization resin was -10 ° C.

This solvent-type graft copolymer resin was diluted with methyl ethyl ketone to a solid content concentration of 5% to prepare a coating liquid for an adhesion-modified layer. Except for the coating liquid for the adhesion-modified layer, a 6-μm-thick biaxially stretched polyethylene terephthalate film provided with an adhesion-modified layer in the same manner as in “Production of a polyester film provided with an adhesion-modified layer” described in Example 1. I got The final coating agent application amount was 0.05 g / m ² .

[0080]

Comparative Example 1 A stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux condenser was charged with 345 parts of dimethyl terephthalate, 211 parts of 1,4-butanediol, 270 parts of ethylene glycol, and tetra-n-butyl. 0.5 part of titanate was charged and transesterification was performed from 160 ° C. to 220 ° C. over 4 hours. Next, 14 parts of fumaric acid and 160 parts of sebacic acid were added, and the temperature was raised from 200 ° C. to 220 ° C. over 1 hour to carry out an esterification reaction. Then, the temperature was raised to 255 ° C., and the pressure in the reaction system was gradually reduced. Then, the reaction was carried out under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a copolymerized polyester. The obtained polyester has a weight average molecular weight of 2,000
0, pale yellow and transparent.

Next, 75 parts of the above-mentioned copolymerized polyester resin, 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were placed in a reactor equipped with a stirrer, a thermometer, a reflux device and a fixed-rate dropping device, and heated and stirred at 65 ° C. The resin was dissolved. After the resin is completely dissolved, methacrylic acid 17.5
And a solution prepared by dissolving 1.2 parts of azobisdimethylvaleronitrile in 25 parts of methyl ethyl ketone was added dropwise to the polyester solution at a rate of 0.2 ml / min. The mixture was further stirred for 2 hours. Continued. After sampling for analysis from the reaction solution, 300 parts of water and 25 parts of triethylamine were added to the reaction solution and stirred for 1 hour. Thereafter, the reactor internal temperature was raised to 100 ° C., and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off to obtain a water-dispersed graft resin. The resulting resin was pale yellow and transparent, and had a glass transition temperature of -20 ° C.

The above-mentioned water-dispersed graft resin was coated in the same manner as in Example 1 to provide a 6 μm thick adhesive-modified layer.
m of biaxially stretched polyethylene terephthalate film. The final coating agent application amount was 0.05 g / m ² .

[0083]

Comparative Example 2 An undrawn polyethylene terephthalate film was obtained in the same manner as in Example 1. Next, the unstretched film was 3.1 times in the longitudinal direction at 100 ° C., and further 99 ° C.
Then, the coating solution described in Example 1 was applied to one surface of the obtained film by a roll coater method, and dried with hot air at 100 ° C. in a preheating zone of a tenter. Next, the above-mentioned coated film is stretched 4.1 times at 105 ° C., then heat-treated at 225 ° C., and further 2.6 ° at 210 ° C.
%, And a relaxation heat treatment of 0.3% at 150 ° C. in the transverse direction to obtain a 6 μm-thick biaxially stretched polyethylene terephthalate film provided with an adhesion modifying layer. The final coating agent application amount was 0.05 g / m ² .

[0084]

Comparative Example 3 A 6 μm-thick biaxially stretched polyethylene terephthalate having an adhesion modifying layer provided in the same manner as in Example 3 except that the stretching ratio in the horizontal direction was changed from 3.6 times to 3.9 times. A film was obtained. Final coating amount is 0.0
It was 5 g / m ² .

[0085]

Comparative Example 4 An undrawn polyethylene terephthalate film was obtained in the same manner as in Example 1. The coating solution described in Example 1 was applied to this unstretched film by a roll coater method and dried with hot air at 100 ° C. in a preheating zone of a tenter. Then, at 90 ° C., 3.43 times in the horizontal direction and 76 ° C. in the vertical direction. And stretched 4.42 times. Then, in the heat setting zone, 2
After re-stretching 1.02 times at 02 ° C, it was heat-treated at 207 ° C. 0.9% at 207 ° C, 0.5% at 150 ° C
After a relaxation heat treatment in the lateral direction, a biaxially stretched polyethylene terephthalate film having a thickness of 6 μm provided with an adhesion modifying layer was obtained. The final coating agent application amount was 0.05 g / m ² .

The properties of the polyester films for sublimation type thermal transfer recording materials obtained in Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 1.

[0087]

[Table 1]

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H111 AA27 BB06 BB08 4F100 AK12B AK12J AK24B AK24J AK41B AK41J AK42A AL04B AT00A BA02 BA10A BA10B BA15 CC01B EJ05B EJ38 GB90 JA20A JB06B JK20BJN18

Claims (3)

[Claims] 1. A polymerizable unsaturated monomer containing at least one monomer containing an acid anhydride having a double bond in a hydrophobic polyester resin on at least one surface of a substrate film having a thickness of 1 to 12 μm. A polyester film for a sublimation type thermal transfer recording material, characterized by having an adhesion modified layer containing a grafted self-crosslinkable polyester-based graft copolymer as a main component. 2. A coating solution containing the self-crosslinkable polyester-based graft copolymer according to claim 1 is applied to an unstretched or uniaxially stretched film, dried, and further stretched uniaxially or more. A polyester film for a sublimation type thermal transfer recording material formed by fixing. 3. The base film having a birefringence of 0.035 to 0.035.
3. The sublimation type according to claim 1, wherein the polymerizable unsaturated monomer is 0.060, and the polymerizable unsaturated monomer contains at least maleic anhydride and styrene. Polyester film for thermal transfer recording material.