JP3289330B2 - Water-soluble copolymerized polyester for film and coating agent for magnetic recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-soluble copolymerized polyester for a film. Specifically, it has excellent water solubility, adhesiveness, blocking resistance, solvent resistance, etc., and is suitable as a coating agent for base films used in magnetic recording materials, various photographic materials, packaging materials, electrical insulating materials, general industrial materials, etc. The present invention relates to a water-soluble copolymerized polyester for a film. More specifically, the present invention relates to a water-soluble copolymerized polyester for film suitable as a coating agent for a base film used in a magnetic recording material.

[0002]

2. Description of the Related Art Polyesters, especially polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate or poly-1,4-cyclohexane dimethylene terephthalate, and polyesters based on these have excellent physical and chemical properties. , Fibers, films or sheets, and molded articles thereof. In particular, polyester films have excellent properties in heat resistance, chemical resistance, and mechanical properties, and are used in many applications such as magnetic recording materials, various photographic materials, packaging materials, electrical insulating materials, and general industrial materials. I have.

[0003] In these applications, the polyester film is not used alone, and various coatings such as a magnetic coating material, a chemical mat coating material, a diazo photosensitive coating material, a gelatin composition, a heat sealing composition, Used by applying or printing ink or the like.

[0004] In particular, films used for magnetic recording materials such as magnetic tapes and floppy disks are required to have flatness and smoothness for high reliability and high density of magnetic recording, and also to have magnetic coating materials. There is a strong demand for improvement in the adhesive strength between the film and the base film. However, when an adhesive force to the magnetic paint is applied to the film, blocking occurs between the films, and various workability is deteriorated and magnetic recording performance is deteriorated. For this reason, in order to impart the adhesiveness of the film, a method which does not cause a blocking phenomenon between the films, and which is resistant to various solvents contained in various coatings applied or printed on the film surface. And an easily adhesive substance is desired.

In general, since polyester itself is inert and has poor adhesiveness, various coatings such as a magnetic coating, a chemical mat coating, a diazo photosensitive coating, a gelatin composition, a heat sealing composition, and an ink are applied to the film surface. When coating or printing, the film surface should be subjected to physical treatment such as corona discharge or plasma or chemical treatment using alkali or amine chemicals in order to improve the adhesion to the coating. There is known a method of coating, and a method of coating an easily adhesive substance. However, the physical or chemical surface treatment method complicates the process, not only increases the cost, but also does not provide sufficient adhesiveness.

On the other hand, a method of coating an easily adhesive substance can be carried out in the process of producing a polyester film, which is advantageous in terms of cost, and enables selection of an adhesive substance which can cope with various coatings. is there. Furthermore, various water-dispersed or water-soluble copolymerized polyesters and films have been proposed from the viewpoint of handleability of polyester films and workability during film production. For example, JP-B-47-40873 and JP-A-50-121336 disclose copolymers of polyester with polyethylene glycol and an ester-forming metal salt of sulfonic acid, JP-A-50-83497 and JP-A-50-83497. 53-25
JP-A-36-3, JP-A-54-3848 and JP-A-59-215318 include those obtained by copolymerizing a metal salt compound of an ester-forming sulfonic acid and an aliphatic dicarboxylic acid component.

[0007]

However, the above-mentioned prior art has the following problems. That is, the conventional water-dispersed or water-soluble copolymerized polyester is used in combination with an ester-forming sulfonic acid metal salt compound and a polyethylene glycol or aliphatic dicarboxylic acid component for the purpose of improving water dispersion or water solubility. Insufficient water dispersion or water solubility, or copolymerization of a large amount of polyethylene glycol and aliphatic dicarboxylic acid components, significantly lowers the glass transition temperature of polyester and exhibits adhesiveness, but the film has blocking resistance. And inferior solvent resistance.

It is an object of the present invention to provide a water-soluble copolyester for a film which solves these drawbacks and has excellent water-solubility, adhesiveness, blocking resistance and solvent resistance and is suitable as a coating agent for a base film. It is in.

[0009]

SUMMARY OF THE INVENTION The object of the present invention described above is to provide an acid component comprising two or more aromatic dicarboxylic acids 70 or more.
Mol% or more, 0.01 to 8 mol% of aliphatic dicarboxylic acid and ester-forming alkali metal salt of sulfonic acid 8
Water-soluble copolymer for films comprising from 2 to 25 mol%, aliphatic glycols having 2 to 8 carbon atoms and / or 80 to 99 mol% of alicyclic glycols having 6 to 16 carbon atoms and 1 to 20 mol% of diethylene glycol as glycol components. Can be achieved by polyester.

The water-soluble copolyester of the present invention contains 70% by mole of two or more aromatic dicarboxylic acids as an acid component.
It is necessary that the content be at least 80 mol%, because it is excellent in adhesiveness, water solubility and solvent resistance. When the content of two or more aromatic dicarboxylic acids is less than 70 mol%, the blocking resistance and the solvent resistance are poor. The aromatic dicarboxylic acid is not particularly limited, for example, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, diphenyl dicarboxylic acid, aromatic dicarboxylic acids such as diphenyl ether dicarboxylic acid, and the like. Two or more aromatic dicarboxylic acids can be appropriately selected from among them. Preferred aromatic dicarboxylic acids are terephthalic acid, isophthalic acid and naphthalenedicarboxylic acid. Of these, it is preferable to select two or more aromatic dicarboxylic acids. Particularly preferred two or more aromatic dicarboxylic acids include terephthalic acid,
Isophthalic acid.

In the present invention, the ratio of two or more aromatic dicarboxylic acids is not particularly limited, but the total amount of one or more aromatic dicarboxylic acids to one aromatic dicarboxylic acid is molar. Preferably, the ratio is 0.001 to 0.1, more preferably 0.005 to 0.05.
It is preferable from the viewpoint of excellent adhesiveness, water solubility and solvent resistance.

Further, the aliphatic dicarboxylic acid in the present invention needs to be 0.01 to 8 mol%, preferably 0.05 to 5 mol%, from the viewpoint of adhesiveness. If the aliphatic dicarboxylic acid is less than 0.01 mol%, the adhesiveness is poor,
If it exceeds 8 mol%, the adhesion is good, but the blocking resistance and the solvent resistance are poor. The aliphatic dicarboxylic acid is not particularly limited, but includes, for example, adipic acid, sebacic acid, azelaic acid, dodecadionic acid, and dimer acid, and among them, preferred aliphatic dicarboxylic acids include adipic acid, Sebacic acid and azelaic acid. Two or more of these aliphatic dicarboxylic acids may be used in combination.

In the water-soluble copolymerized polyester of the present invention, it is necessary that the ester-forming sulfonic acid alkali metal salt compound is contained in an amount of 8 to 25 mol%, preferably 10 to 20 mol%, based on all the acid components. More preferably, 11 to 1
5 mol%. If the amount of the ester-forming sulfonic acid alkali metal salt compound is less than 8 mol%, sufficient water solubility and adhesiveness cannot be obtained. On the other hand, if it exceeds 25 mol%, the adhesiveness reaches saturation, and conversely, the blocking resistance and the solvent resistance decrease. The ester-forming sulfonic acid alkali metal salt compound is not particularly limited, but examples thereof include sulfoterephthalic acid, 5-sulfoisophthalic acid, 2-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2, Examples thereof include alkali metal salts such as 6-dicarboxylic acid and alkyl esters thereof.
Among them, lithium, sodium and potassium salts of 5-sulfoisophthalic acid and sulfoterephthalic acid are more preferably used.

The glycol component of the water-soluble copolymerized polyester of the present invention is an aliphatic glycol having 2 to 8 carbon atoms and / or an alicyclic glycol having 6 to 16 carbon atoms, 80 to 99.
Mol% and 1 to 20 mol% of diethylene glycol. Preferably an aliphatic glycol having 2 to 8 carbon atoms and / or an alicyclic glycol 8 having 6 to 16 carbon atoms
2.5 to 95 mol%, diethylene glycol 5 to 17.
5 mol%, more preferably 85 to 92.5 mol% of an aliphatic glycol having 2 to 8 carbon atoms and / or an alicyclic glycol having 6 to 16 carbon atoms, and 7.5 to 15 mol% of diethylene glycol. Less than 80 mol% of aliphatic glycol having 2 to 8 carbon atoms and / or alicyclic glycol having 6 to 16 carbon atoms or 2
When it exceeds 0 mol%, blocking resistance and solvent resistance are inferior. On the other hand, aliphatic glycols having 2 to 8 carbon atoms and / or
Or 99 mol% of an alicyclic glycol having 6 to 16 carbon atoms
Or 1 mol% of diethylene glycol
If it is less than 1, the blocking resistance is good, but the adhesion is poor.

The aliphatic glycol having 2 to 8 carbon atoms and / or the alicyclic glycol having 6 to 16 carbon atoms of the present invention include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, Pentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3
And glycols such as -cyclohexanedimethanol and 1,4-cyclohexanedimethanol.
Preferred examples of the aliphatic glycol having 2 to 8 carbon atoms and / or the alicyclic glycol having 6 to 16 carbon atoms include ethylene glycol, neopentyl glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Preferred are ethylene glycol, 1,4-butanediol and 1,4-cyclohexanedimethanol. These glycols may be used alone or in combination of two or more.

The water-soluble copolyester of the present invention may be partially copolymerized with an oxyacid or a polyoxyalkylene glycol within a range not to impair the effects of the present invention. Another compound such as a functional compound may be copolymerized.

Further, the water-soluble copolymerized polyester of the present invention contains 1 to 500 ppm of an alkaline earth metal and at least one metal element selected from Mn, Zn and Co in order to improve blocking resistance and solvent resistance. , At least one metal element selected from alkali metals
It is preferably contained at 00 ppm. The method for causing the water-soluble copolymerized polyester to contain the alkaline earth metal and at least one metal element selected from Mn, Zn, and Co, and at least one metal element selected from the alkali metals is particularly limited. However, it can be contained, for example, by adding a metal compound during production of the water-soluble copolymerized polyester. The metal compounds to be added include alkaline earth metals and Mn, Zn, C
o, and an alcoholate of an alkali metal, a chloride, and a glycol-soluble salt of a monocarboxylic acid. Preferred compounds of the alkaline earth metal and Mn, Zn, and Co are calcium acetate, magnesium acetate, manganese acetate, zinc acetate, and cobalt acetate. The addition amount is 0.001 to water-soluble copolymerized polyester.
0.5% by weight is preferable, and 0.005 to 0.3%
% By weight is preferred. Preferred alkali metal compounds include lithium acetate, sodium acetate, and potassium acetate, with lithium acetate being preferred. The amount added is preferably 0.001 to 1.5% by weight based on the water-soluble copolymerized polyester, and more preferably 0.01 to 1.5% by weight.
1-1.0% by weight is preferred.

The process for producing the water-soluble copolymerized polyester of the present invention includes, for example, a water-soluble copolymer comprising terephthalic acid, isophthalic acid, adipic acid, 5-sodium sulfoisophthalic acid component as an acid component and ethylene glycol and diethylene glycol as a glycol component. To explain the copolymerized polyester, terephthalic acid, isophthalic acid, adipic acid, 5-sodium sulfoisophthalic acid and ethylene glycol, a direct esterification reaction with diethylene glycol, or dimethyl terephthalate,
Produced by a first step of transesterifying dimethyl isophthalate, dimethyl adipate, dimethyl 5-sodium sulfoisophthalate, ethylene glycol and diethylene glycol, and a second step of subjecting the reaction product of the first step to a polycondensation reaction. And the like.

At this time, as a reaction catalyst, conventionally known alkali metals, alkaline earth metals, manganese, cobalt, zinc, antimony, germanium, titanium compounds and the like are used. Good.

The intrinsic viscosity of the water-soluble copolymerized polyester of the present invention is not particularly limited.
It is preferably at least 0.35, more preferably at least 0.35, particularly preferably at least 0.4.

The water-soluble copolymerized polyester of the present invention may contain a flame retardant, a heat stabilizer, an ultraviolet absorber, a pigment,
Dyes, fatty acid esters, organic lubricants such as waxes or antifoaming agents such as polysiloxanes may be blended, and clay, mica, titanium oxide, calcium carbonate, kaolin, wet and dry types are used for the purpose of imparting lubricity and the like. Inorganic particles such as modified silica, colloidal silica, calcium phosphate, barium sulfate, and alumina, as well as organic particles containing acrylic acid, styrene, and the like as components may be blended.

The water-soluble copolyester of the present invention is suitably used as a coating agent for various films for the purpose of imparting adhesiveness. In this case, the copolyester is dissolved in water and used as an aqueous solution. This aqueous solution does not have strictness in a physical or chemical sense, and includes an aqueous solution which is mostly dissolved in water and partially finely dispersed. Further, when the water-soluble copolymerized polyester is made water-soluble or in the aqueous solution, the above-mentioned organic lubricant, antifoaming agent, various kinds of particles and the like may be added as necessary.

As a specific method for producing a film using the water-soluble copolyester of the present invention, for example, a case where the water-soluble copolyester of the present invention is applied to a film made of polyethylene terephthalate will be described. After drying terephthalate,
Melt extrusion into an unstretched sheet, followed by heat treatment to form a film. The biaxial stretching may be any of longitudinal, transverse sequential stretching or biaxial simultaneous stretching, and the stretching ratio is not particularly limited, but is usually 2.0 to 2.0 in each of longitudinal and transverse directions.
A value of 5.0 is appropriate. Also, after biaxial stretching, further vertical,
It may be redrawn in any of the transverse directions.

The application of the aqueous solution of the water-soluble copolymerized polyester of the present invention to the surface of the polyester film is preferably carried out during the production process of the polyester film. More preferably, the unstretched sheet is oriented in either the vertical or horizontal direction. After uniaxial stretching, a method of applying an aqueous solution of a water-soluble copolymerized polyester, and then biaxially stretching in a direction different from the uniaxial stretching and heat treatment to produce a film is preferred. As a coating method, a known coating method, for example, a reverse coating method, a gravure coating method, a die coating method, a wire bar method, or the like can be used.

The water-soluble copolymerized polyester of the present invention can be used as a fiber coating agent, a coating agent for other molded products and a sizing agent in a weaving process, in addition to a film coating agent.

[0026]

The present invention will be described in more detail with reference to the following examples. The characteristics in the examples were measured as follows.

A. Intrinsic viscosity of copolymerized polyester:
[Η] Measured at 25 ° C. using an o-chlorophenol solvent.

B. Water solubility of copolymerized polyester 2 g of copolymerized polyester was put in 100 g of water,
After stirring and dissolving at 2 ° C. for 2 hours and cooling, the mixture was filtered through a 2μ filter. The water solubility of the copolymerized polyester was determined based on the dissolved state and the amount of the residue on the filter. ：: The aqueous solution was transparent or slightly cloudy, but almost no filtered product was observed. Δ: The aqueous solution was slightly cloudy, and a filtered product was observed. X: It was difficult to dissolve, or the aqueous solution was strongly cloudy, and a large amount of filtered product was observed.

C. Adhesiveness An aqueous solution of a copolymerized polyester is applied, and Diferacoat VD1654 (manufactured by Dainichi Seika Kogyo Co., Ltd.) 100 parts by weight and Sumidur N75 (manufactured by Sumitomo Bayer Co., Ltd.) 1 wt. After drying, the coating composition was applied with a bar coater so as to have a thickness of 5 μm and dried at 100 ° C. for 5 minutes to form a coating layer. A cellophane adhesive tape is adhered to the surface of the coating layer, and after passing through a nip roll having a linear pressure of 50 kg / cm, the tape is rapidly peeled in a direction of 180 degrees. At that time, the area of the coating layer adhered to the cellophane pressure-sensitive adhesive tape was determined to determine the adhesiveness. ：: The area of the coating layer adhered to the cellophane adhesive tape was 5%
Less than that, and excellent in adhesiveness. ：: The area of the coating layer adhered to the cellophane adhesive tape is 5%
It is less than 10% and is slightly superior in adhesiveness. Δ: Area of coating layer adhered to cellophane adhesive tape was 10
% To less than 30%, and slightly inferior in adhesiveness. ×: The area of the coating layer adhered to the cellophane adhesive tape was 30.
% Or more and is inferior in adhesiveness.

D. Blocking resistance An aqueous solution of a copolymerized polyester is applied, and the adhesive layer surfaces of the film provided with the adhesive layer are superposed (a) and the film surface having no adhesive layer is provided on the adhesive layer surface of the film provided with the adhesive layer. The superposed product (b) (superimposed area: 3 cm × 4 cm) was subjected to a load of 500 g / 12 cm ² and allowed to stand at 50 ° C. and 85% RH for 24 hours. The measurement was carried out at a tensile speed of 20 cm / min using a machine.

E. Solvent resistance An aqueous solution of a copolymerized polyester was applied, and methyl ethyl ketone, toluene, and acetone were each dropped as organic solvents on the surface of the adhesive layer of the film provided with the adhesive layer. ：: Almost no cloudiness. Δ: slightly cloudy X: Cloudy.

Example 1 78.7 parts by weight of dimethyl terephthalate, 2.8 parts by weight of dimethyl isophthalate, 2.5 parts by weight of dimethyl adipate, and dimethyl 5-sodium sulfoisophthalate.
0 parts by weight, 59.9 parts by weight of ethylene glycol, 4.0 parts by weight of diethylene glycol and 0.1 part of calcium acetate.
One part by weight, 0.3 part by weight of lithium acetate and 0.03 part by weight of antimony trioxide were added, and the mixture was subjected to a transesterification reaction according to a conventional method, and then 0.05 part by weight of trimethyl phosphate was added. Then, the temperature was gradually raised and reduced, and finally 280
A polycondensation reaction was carried out at a temperature of 1 mmHg or lower at a temperature of 1 ° C. to obtain a water-soluble copolymerized polyester. The composition of the obtained water-soluble copolymerized polyester was measured by NMR ( ¹³ C-NMR spectrum). As a result, the acid components were 82 mol% of terephthalic acid, 3.0 mol% of isophthalic acid, 3.0 mol% of adipic acid, -12 mol% of sodium sulfoisophthalic acid, the glycol component was 87 mol% of ethylene glycol, and 13 mol% of diethylene glycol. The intrinsic viscosity is 0.57,
The metal content determined by the atomic absorption method was Ca205pp
m and Li were 190 ppm.

2 g of the obtained water-soluble copolyester was placed in 100 g of water, dissolved by stirring at 80 ° C. for 2 hours, cooled, and filtered through a 2 μ filter to obtain a water-soluble copolyester aqueous solution. The aqueous solution of the water-soluble copolymerized polyester was almost transparent, and no filtered product was observed.

On the other hand, after sufficiently drying polyethylene terephthalate having an intrinsic viscosity of 0.60 containing 0.2% by weight of silicon dioxide having an average particle size of 0.2 μm, it is supplied to an extruder and melted at 290 ° C. It was extruded into a sheet from a die and cooled and solidified with a cooling drum at 30 ° C. to obtain an unstretched film. Next, the unstretched film was heated to 95 ° C. and stretched 3.4 times in the machine direction to obtain a uniaxially stretched film. Further, the aqueous solution of the water-soluble copolymerized polyester obtained above was applied to one surface of the uniaxially stretched film by a gravure coating method so that the coating thickness after the biaxial stretching was 0.1 μm. Subsequently, the film was heated to 100 ° C., stretched 3.5 times in the transverse direction, and heat-treated at 200 ° C. to obtain a 15 μm-thick polyester film having an adhesive layer. Table 2 shows the properties of the obtained film. The adhesiveness, blocking resistance and solvent resistance of the film were all good.

Example 2 78.3 parts by weight of dimethyl terephthalate, 1.0 part by weight of dimethyl isophthalate, 4.3 parts by weight of dimethyl adipate, and dimethyl 5-sodium sulfoisophthalate.
5 parts by weight, 61.0 parts by weight of ethylene glycol, 0.07 parts by weight of calcium acetate, 0.07 parts by weight of lithium acetate and 0.03 parts by weight of antimony trioxide were added, and subjected to a transesterification reaction according to a conventional method. 0.05 parts by weight of trimethyl acid were added. Then, the temperature was gradually increased and the pressure was reduced, and finally a polycondensation reaction was performed at 280 ° C. and 1 mmHg or less, to obtain a water-soluble copolymerized polyester. The composition of the obtained water-soluble copolymerized polyester was measured by NMR ( ¹³ C-NMR spectrum). As a result, the acid components were 82 mol% of terephthalic acid, 1.0 mol% of isophthalic acid, 5.0 mol% of adipic acid, and 5 mol% of adipic acid. -Sodium sulfoisophthalic acid 12
The mol% and the glycol component were ethylene glycol 90 mol% and diethylene glycol 10 mol%. Also,
The intrinsic viscosity was 0.56, and the metal content determined by the atomic absorption method was 150 ppm of Ca and 45 ppm of Li.

2 g of the obtained water-soluble copolymerized polyester was placed in 100 g of water, stirred and dissolved at 80 ° C. for 2 hours, cooled, and filtered with a 2 μ filter to obtain an aqueous solution of the water-soluble copolymerized polyester. The aqueous solution of the water-soluble copolymerized polyester was almost transparent, and no filtered product was observed.

On the other hand, a 15 μm thick polyester film having an adhesive layer was obtained in the same manner as in Example 1. Table 2 shows the properties of the obtained film. Film adhesion,
Both blocking resistance and solvent resistance were good.

Comparative Example 1 83.6 parts by weight of dimethyl terephthalate, 17.4 parts by weight of dimethyl 5-sodium sulfoisophthalate, 61.0 parts by weight of ethylene glycol and 0.1 part of calcium acetate
Parts by weight and 0.03 parts by weight of antimony trioxide were added, and the mixture was subjected to a transesterification reaction according to a conventional method, and then 0.05 parts by weight of trimethyl phosphate was added. Then, the temperature was gradually increased and the pressure was reduced, and finally a polycondensation reaction was performed at 280 ° C. and 1 mmHg or less, to obtain a water-soluble copolymerized polyester. The composition of the obtained water-soluble copolymerized polyester was determined by NMR ( ¹³ C-NMR
Spectrum), the acid component was terephthalic acid 88 mol%, 5-sodium sulfoisophthalic acid 12
The mol% and the glycol component were 83 mol% of ethylene glycol and 17 mol% of diethylene glycol. Also,
The intrinsic viscosity was 0.55, and the metal content determined by the atomic absorption method was 210 ppm of Ca.

2 g of the obtained water-soluble copolymerized polyester was placed in 100 g of water, stirred and dissolved at 80 ° C. for 2 hours, cooled, and filtered through a 2 μ filter to obtain an aqueous solution of the water-soluble copolymerized polyester. The aqueous solution of the water-soluble copolymerized polyester was slightly cloudy, and a filtered product was observed.

On the other hand, a 15 μm thick polyester film having an adhesive layer was obtained in the same manner as in Example 1. Table 2 shows the properties of the obtained film. The film had poor adhesion.

Examples 3 to 5 and Comparative Examples 2 to 4 Polyesters and films were obtained in the same manner as in Example 1 except that the types and amounts of the acid component, glycol component and metal compound were changed as shown in Table 1. . Table 2 shows the results.
Examples 3 to 5 were within the scope of the present invention, and the film had good adhesion, blocking resistance and solvent resistance.

On the other hand, in Comparative Example 2, the amount of the aliphatic dicarboxylic acid was out of the range of the present invention, and although the adhesiveness of the film was good, the blocking resistance and the solvent resistance were inferior. In Comparative Example 3, the amount of diethylene glycol was out of the range of the present invention, and the blocking resistance and the solvent resistance were poor.

Further, in Comparative Example 4, the ester-forming sulfonic acid alkali metal salt compound was outside the scope of the present invention, and the obtained copolymerized polyester was poor in water solubility.

[0044]

[Table 1]

[Table 2]

[0045]

As described above, the present invention relates to a metal salt of a specific amount of two or more aromatic dicarboxylic acids, aliphatic dicarboxylic acids and ester-forming sulfonic acid compounds as an acid component.
It is a water-soluble copolymerized polyester for films comprising a specific amount of an aliphatic glycol having 2 to 8 carbon atoms and / or an alicyclic glycol having 6 to 16 carbon atoms as a glycol component, and diethylene glycol. Excellent solvent resistance, coating material for base film used for magnetic recording materials, various photographic materials, packaging materials, electrical insulating materials, general industrial materials, etc., especially for base films used for magnetic recording materials It is preferably used for a coating agent.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C08G 63/00-63/91

Claims (4)

(57) [Claims] 1. An acid component comprising at least 70 mol% of two or more aromatic dicarboxylic acids and 0.01 to 8 aliphatic dicarboxylic acids.
Mole% and 8 to 25 mole% of an ester-forming sulfonic acid alkali metal salt compound, as a glycol component, an aliphatic glycol having 2 to 8 carbon atoms and / or a 6-1 carbon atom.
6. A water-soluble copolymerized polyester for films comprising 80 to 99 mol% of alicyclic glycol and 1 to 20 mol% of diethylene glycol. 2. The two or more aromatic dicarboxylic acids, wherein the total amount of one or more aromatic dicarboxylic acids to one aromatic dicarboxylic acid is 0.001 to 0.001.
2. The water-soluble copolymerized polyester for a film according to claim 1, which is 0.1. Wherein said two or more aromatic dicarboxylic acids, terephthalic acid, according to claim 1 or a member selected from the group consisting of isophthalic acid and naphthalene dicarboxylic acid
3. The water-soluble copolymerized polyester for a film according to 2 . 4. A film according to claim 1, wherein
Coatings for magnetic recording materials comprising a use a water-soluble copolymerized polyester.