JP3040790B2 - Polyester film and polyester film or photographic light-sensitive material having a polyester copolymer and an undercoat layer containing the polyester copolymer - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a polyester copolymer and a polyester film having an undercoat layer containing the polyester copolymer. The present invention relates to a polyester film having an undercoat layer which is improved and has excellent adhesion to a hydrophilic colloid layer.

[Prior art] Polyester films, especially polyethylene terephthalate biaxially oriented films are used as bases for photographic films, drawings, and magnetic recording tapes because of their transparency, dimensional stability, and excellent mechanical properties. Have been. In these applications, the adhesion between the polyester support and the surface layer material is usually improved by providing an undercoat layer between the polyester support and the surface material. On the other hand, conventionally, for improving the adhesiveness between a linear polyester and a metal foil, various plastics, and particularly a hydrophilic resin such as gelatin, an undercoating layer is required because of problems in working environment and explosion-proof equipment is not required. It has been proposed to use a water-soluble or water-dispersible polyester copolymer. As such an example, for example, Japanese Patent Publication No. 47-40873
In JP-A No. 11-139, there is described a copolymer in which an ester-forming sulfonic acid metal base-containing compound is used in an amount of 8 mol% or more based on the total acid component and polyethylene glycol is used in an amount of 20 mol% or more based on the total glycol component for the purpose of water dissipation. However, when these are used as an undercoat layer, it can be easily inferred that the water resistance of the undercoat layer, that is, the water resistance of adhesion is lowered. In Japanese Patent Publication No. 56-5476, a saturated linear aliphatic dicarboxylic acid having 4 to 8 methylene groups is used for the purpose of improving adhesiveness, but in this case, the water resistance of the undercoat layer is also insufficient. Not a thing. Further, in Japanese Patent Application Laid-Open No. 56-88454, a substantially water-insoluble aqueous dispersion is used to improve the water resistance.In this case, however, the dispersion contains a water-soluble organic solvent. Problems such as work environment remain. JP-A-60-248231 is almost the same as JP-A-56-88454, but differs mainly in that the final aqueous dispersion does not contain an organic solvent. However, since an organic solvent is used in the process of preparing the aqueous dispersion, the process of preparing the aqueous dispersion becomes complicated in addition to the problem of the working environment, which is not preferable in practical use. In JP-A-56-95959, there is a problem that the adhesiveness is insufficient, and that the aqueous dispersion tends to become a gel at room temperature unless the intrinsic viscosity of the resin is controlled to a considerably low value.

[Problems to be Solved by the Invention] Although any of the conventional undercoating layers containing a polyester copolymer has relatively easy adhesion to a polyester support, hydrophilic colloids such as polyvinyl alcohol and gelatin can be obtained. No adhesive having sufficient water resistance could be obtained.

Also, if the glass transition temperature is increased to maintain the mechanical properties at relatively high temperature and to improve the water resistance of bonding,
There is a problem that the adhesive strength is significantly reduced due to residual stress when stretching after coating and drying.

A first object of the present invention is to provide a water-soluble or water-dispersible polyester copolymer which can be used with few problems in the working environment and can simplify the equipment.

A second object of the present invention is to provide an undercoat layer having excellent coatability as an aqueous solution and excellent adhesion to a polyester support, and excellent adhesion to a hydrophilic colloid layer such as polyvinyl alcohol and gelatin and its water resistance. To obtain a polyester film having the following.

A third object of the present invention is to provide a photographic material having a subbing layer containing a water-soluble polyester copolymer and a silver halide emulsion layer.

Still another object of the present invention is to obtain a polyester film having an undercoat layer that exhibits good adhesion to a binder used for a magnetic layer or the like.

[Means for Solving the Problems] The present inventors have conducted intensive studies to obtain a polyester film having an undercoat layer having the contradictory properties of water solubility and water resistance as described above. I came to find it. That is, the object of the present invention is a polyester copolymer comprising at least the following components (A), (B), (C), (D), (E) and (F), and ) And component (B) in a molar ratio of 30/70 to 70/30, component (C) is 5 to 15 mol% based on all dicarboxylic acid components, and component (D) is 10 mol based on all dicarboxylic acid components. %that's all,
Component (E) is at least 50 mol% based on the total glycol components, and component (F) is from 1 to 5% based on the polyester copolymer.
It is achieved by providing a polyester film comprising a polyester copolymer characterized by being used at 10% by weight and an undercoat layer containing the polyester copolymer on at least one surface.

(A) Terephthalic acid and / or its ester-forming derivative (B) Isophthalic acid and / or its ester-forming derivative (C) Dicarboxylic acid having a sulfonic acid salt and / or its ester-forming derivative (D) Alicyclic Dicarboxylic acid and / or ester-forming derivative thereof (E) Ethylene glycol (F) Polyethylene glycol having a number average molecular weight of 400 to 40,000 Hereinafter, the present invention will be described in more detail.

In the present invention, terephthalic acid and / or its ester-forming derivative (terephthalic acid component) and isophthalic acid and / or its ester-forming derivative (isophthalic acid component) are used, and the ratio of the terephthalic acid component and the isophthalic acid component is It is necessary that it is used in a molar ratio of 30/70 to 70/30 from the viewpoint of applicability to a polyester support and solubility in water. It is further preferred that these terephthalic acid component and isophthalic acid component are used in an amount of 50 to 80 mol% based on the total dicarboxylic acid component.

Further, as the dicarboxylic acid having a sulfonic acid salt and / or an ester-forming derivative thereof used in the present invention, those having an alkali metal salt of a sulfonic acid are particularly preferable, and examples thereof include 4-sulfoisophthalic acid, 5-sulfoisophthalic acid, and sulfoisophthalic acid. Terephthalic acid, 4-sulfophthalic acid, 4
-Sulfonaphthalene-2,7-dicarboxylic acid, 5- [4-
Sulfophenoxy] isophthalic acid or other alkali metal salts or ester-forming derivatives thereof are used, and sodium 5-sulfoisophthalate or ester-forming derivatives thereof are particularly preferred. The dicarboxylic acid having a sulfonic acid salt and / or an ester-forming derivative thereof has a water-soluble and water-resistant content of 5 to 5 parts with respect to all dicarboxylic acid components.
It is used in the range of 15 mol%, particularly preferably in the range of 6 to 10 mol%.

Examples of the alicyclic dicarboxylic acid and / or its ester-forming derivative include 1,4-cyclohexanedicarboxylic acid, 1,3
-Cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 4,
4'-Bicyclohexyldicarboxylic acid or the like or an ester-forming derivative thereof is used, and these are used in an amount of 10 mol% based on the total dicarboxylic acid component in view of the viscosity of the aqueous resin solution.
It is preferable to use the above, and if the amount is too small, the viscosity increases, which may cause a problem in coatability.

In the present invention, an aromatic dicarboxylic acid or an ester-forming derivative thereof may be used as a dicarboxylic acid component other than the above in an amount of 30 mol% or less of the total dicarboxylic acid component. These dicarboxylic acid components include, for example, phthalic acid, 2,5-dimethylterephthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, aromatic dicarboxylic acids such as biphenyldicarboxylic acid, and esters thereof. Derivatives. Further, a linear aliphatic dicarboxylic acid or an ester-forming derivative thereof may be used in a range of 15 mol% or less of the total dicarboxylic acid component. Examples of such a dicarboxylic acid component include aliphatic dicarboxylic acids such as adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, and ester-forming derivatives thereof. If the amount of the linear aliphatic dicarboxylic acid component is too large, not only blocking becomes easy, but also the water resistance of the adhesive becomes poor.

In the present invention, it is necessary to use a polyethylene glycol having a number average molecular weight of 400 to 4000 by 1 to 10% by weight based on the polyester copolymer of the present invention, and particularly 3 to 10% by weight.
It is preferable to use 8% by weight. If the amount is less than 1% by weight, the effect of improving the fluidity of the resin is small, and if it exceeds 10% by weight, the water resistance of the adhesive becomes poor.

In the present invention, from the viewpoint of the mechanical properties of the polyester copolymer and the adhesion to the polyester support, ethylene glycol is used in an amount of 50 mol% or more based on all glycol components. As the glycol component used in the present invention, in addition to ethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol and the like may be used in combination.

As the polymerization method of the copolymerized polyester in the present invention, various ordinary methods are used. For example, a transesterification reaction of dimethyl ester of dicarboxylic acid and glycol is performed, and after methanol is distilled off, a method of performing polycondensation under a gradually reduced pressure and high vacuum, or an esterification reaction of dicarboxylic acid and glycol is performed. After distilling off the generated water, gradually reducing the pressure, under high vacuum, a method of performing polycondensation,
Alternatively, when a dimethyl ester of a dicarboxylic acid and a dicarboxylic acid are used in combination as a raw material, an ester exchange reaction between the dimethyl ester of the dicarboxylic acid and the glycol is performed, and then an esterification reaction is performed by adding the dicarboxylic acid, followed by polycondensation under high vacuum. There is a way to do it. However, the polyethylene glycol is usually added before polycondensation under reduced pressure.

As the transesterification catalyst, other known ones such as manganese acetate, calcium acetate, and zinc acetate can be used.As the polycondensation catalyst, other known ones such as antimony trioxide, germanium oxide, dibutyltin oxide, and titanium tetrabutoxide can be used. Can be used. Further, phosphorus compounds such as trimethyl phosphate and triphenyl phosphate and hindered phenol compounds such as Irganox 1010 may be used as stabilizers. However, polymerization method, catalyst,
Various conditions such as a stabilizer are not limited to the above examples.

Although the polyester copolymer of the present invention has water solubility,
The term "water-soluble" as used in the present invention does not mean strictly physicochemically, but also includes those that dissolve and / or finely disperse in water. In addition, the intrinsic viscosity of the polyester copolymer of the present invention is preferably 0.3 dl / g or more. If the intrinsic viscosity is too low, it will be difficult to obtain a sufficient adhesive strength.

In the present invention, a polyester film is prepared by providing an undercoat layer containing the polyester copolymer as described above on at least one surface of the support.

The undercoat layer coating solution containing the polyester copolymer further contains a surfactant, an antistatic agent, a matting agent, and a water-soluble or water-dispersible polymer other than the polyester copolymer of the present invention, which impairs the effects of the present invention. You may add in the range which does not exist.

Examples of the polyester support used in the polyester film of the present invention include those comprising a linear saturated polyester synthesized from an aromatic dibasic acid or an ester-forming derivative thereof and a diol or an ester-forming derivative thereof. Specific examples of such polyesters include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, and the like. In addition, those obtained by blending a small amount of these copolymers and other resins are also included. Further, a polyester support into which a white pigment such as titanium oxide or barium sulfate is kneaded can also be mentioned.

Further, the polyester film of the present invention is coated with an undercoat layer coating solution containing the polyester copolymer of the present invention on at least one surface of the polyester support before the completion of the orientation crystallization, dried, and then dried in at least one direction. It is preferable to obtain it by stretching and heat setting to complete orientation crystallization.

The application of the undercoat layer coating solution to the polyester support is carried out in a usual coating step, i.e., the biaxially stretched and heat-set polyester support is separated from the production process of the support and the undercoat layer coating solution is separated in a separate step. Of course, a coating method is also possible, but such a method requires a separate step and is disadvantageous in cost. Therefore, from such a viewpoint, a method of applying the undercoat layer coating solution in the polyester support production process is preferred. In particular, it is preferable to coat at least one surface of the polyester support at any point before the completion of the orientation crystallization in the process as described above, for example, by cooling on a polyester cooling drum melt-extruded into a film from a die. The unstretched film thus obtained is pre-heated, vertically stretched, then coated with an undercoat layer coating solution, dried, further preheated, horizontally stretched, and heat-fixed. Before applying the undercoat layer coating solution, surface treatment such as corona discharge and glow discharge may be performed.

In the present invention, the polyester support before the completion of the orientation crystallization is an unstretched film obtained by directly melting a polyester polymer into a film, or a uniaxial stretching in which the unstretched film is stretched in any one of the vertical and horizontal directions. Film refers to a biaxially stretched film that has been stretched biaxially in the vertical or horizontal direction, and has not been stretched in any one of the vertical and horizontal directions to complete orientation crystallization.

Both the vertical stretching and the horizontal stretching are usually performed at a magnification of 2.0 to 5.0 times.

The concentration of the undercoat layer coating solution is usually 15% by weight or less, preferably 10% by weight or less. Application amount is film
The coating liquid weight is preferably 1 to ²⁰ g, more preferably 5 to 15 g per 1 m ² .

Various known methods can be applied as the coating method. For example, a roll coating method, a gravure roll method, a spray coating method, an air knife coating method, a bar coating method, an impregnation method, a curtain coating method, or the like can be applied alone or in combination.

The polyester film before completion of the orientation crystallization applied as described above is guided to a process such as stretching and heat setting after drying. The undercoat layer thus provided on the support shows good adhesion and water resistance to hydrophilic colloids such as polyvinyl alcohol and gelatin.

In the present invention, various films can be produced by providing at least one hydrophilic colloid layer on the undercoat layer. For example, a photographic light-sensitive material having at least one silver halide emulsion layer above a subbing layer containing the polyester copolymer of the present invention with respect to a support may be mentioned. In the polyester film of the present invention, a binder such as a magnetic layer may be provided on the undercoat layer instead of the hydrophilic colloid layer.

Examples of the hydrophilic colloid used in the hydrophilic colloid layer include proteins such as gelatin, albumin and casein; cellulose derivatives such as hydroxyethylcellulose, carboxymethylcellulose and cellulose sulfates; sugar derivatives such as sodium alginate and starch derivatives; Polyvinyl alcohol, polyvinyl alcohol partial acetal, poly-N-vinylpyrrolidone, polyacrylic acid, polymethacrylic acid, polyacrylamide, polyvinylimidazole, polyvinylimidazole, etc. Although gelatin can be used, gelatin is preferably used. Examples of gelatin include lime-processed gelatin, acid-processed gelatin, and Bull Society Science Photography Japan (Bull. Soc. Sci. Phot. Japan), No. 16,
Oxygen-treated gelatin as described on page 30 (1966) may be used, or a hydrolyzate or enzymatic degradation product of gelatin may be used. Further, a gelatin derivative, a graft of gelatin with another polymer may be used. Polymers can also be used.

In the photographic light-sensitive material of the present invention, as the silver halide emulsion used in at least one silver halide emulsion layer provided above the undercoat layer, various conventional silver halide emulsions can be arbitrarily used. The emulsion can be chemically sensitized by a conventional method, and can be optically sensitized to a desired wavelength region by using a sensitizing dye.

Further, an antifoggant, a stabilizer, a hardener and the like can be added to the silver halide emulsion. As the binder for the emulsion, the hydrophilic colloid as described above is used, but gelatin is advantageously used.

The silver halide emulsion layer and other hydrophilic colloid layers
The hardening agent can be used to increase the film strength. Examples of such hardening agents include aldehyde, aziridine, isoxazole, epoxy, vinyl sulfone, acryloyl, carbodiimide, triazine, and polymer. Molds, other maleic, acetylene, and methanesulfonic acid ester hardeners can be used alone or in combination. Also, a plasticizer, a dispersion (latex) of a water-insoluble or hardly soluble synthetic polymer, a coupler, a coating aid, an antistatic agent, a formalin scavenger, a fluorescent brightener, a matting agent, a lubricant, an image stabilizer, and a surfactant. Agent,
A color fog inhibitor, a development accelerator, a development retarder, a bleaching accelerator, and the like can be contained.

In the photographic light-sensitive material of the present invention, the hydrophilic colloid layer other than the silver halide emulsion layer includes auxiliary layers such as a protective layer, a filter layer, a back coating layer, an antihalation layer, an antiirradiation layer, and an intermediate layer. .

The present invention can be applied to various photographic light-sensitive materials such as X-ray light-sensitive materials, printing light-sensitive materials, photographic light-sensitive materials, and ornamental light-sensitive materials.

[Effects of the Invention] (1) Since the polyester copolymer of the present invention can be used as an aqueous solution, there is no problem in the working environment such as toxicity and flammability, and the equipment can be simplified as compared with the case of using an organic solvent when used. .

(2) When the polyester copolymer of the present invention is used as an undercoat layer, it exhibits particularly excellent adhesion between the polyester support and the hydrophilic colloid layer and exhibits excellent water resistance.

(3) Since the alicyclic dicarboxylic acid is used for the polyester copolymer, the aqueous solution can be prevented from becoming a gel at a solid concentration of 15% by weight or less, exhibiting good coatability, and being linear. Compared with the case where the viscosity of the aqueous solution is lowered by using the aliphatic dicarboxylic acid, the adhesion excellent in water resistance can be performed when used as the undercoat layer.

(4) Since the coating solution containing the polyester copolymer of the present invention exhibits an appropriate viscosity as an aqueous solution, particularly excellent effects can be exhibited when the coating solution is applied to a polyester support before the completion of oriented crystallization.

(5) When the polyester copolymer of the present invention is stretched after coating and drying, it has good fluidity despite having a relatively high glass transition temperature, and therefore has excellent adhesion even at a low heat setting temperature. Is shown.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples.

In addition, the following measurement was performed about the obtained polyester copolymer and the film which has an undercoat layer, and it evaluated according to the following reference | standard.

(1) Intrinsic viscosity: measured at 20 ° C. in a phenol / 1,1,2,2-tetrachloroethane = 60/40 (weight ratio) mixed solution.

(2) Water solubility: 425 g of water was added to 75 g of the polyester copolymer, and the mixture was stirred at 95 ° C. for 3 to 6 hours to evaluate.

(3) Aqueous solution viscosity: measured at 20 ° C. as an 8% by weight aqueous solution.

(4) Coatability: An 8 wt% aqueous solution of the polyester copolymer was applied to a uniaxially stretched polyethylene terephthalate support with a wire bar at a predetermined coating thickness. The coating state at that time was visually evaluated.

The evaluation criteria are shown below.

 ○ It can be applied uniformly and evenly.

Δ: Streaks or slight pinhole cissing occur on the coated surface.

 C: Repelling occurs over the entire surface, making it impossible to apply uniformly.

(5) Adhesion to a support: an unstretched film (thickness of 1000 μm) obtained by quenching polyethylene terephthalate melt-extruded into a film at 280 ° C. from a T-die on a cooling drum
m) is preheated to 75 ° C, then vertically stretched (3 times) and then corona discharged.
The coating solution for the undercoat layer is applied to the surface of the surface-treated support, dried and preheated in a tenter, stretched horizontally (3 times) at 100 ° C., and heat-set at various temperatures shown in Tables 1 and 2 to form a film. 0.3g / m thickness
A polyethylene terephthalate film subjected to a subbing treatment in ² (in terms of polymer) was obtained.

A 45 ° cut was made on the surface of the undercoat layer of the polyethylene terephthalate film with a razor, and a cellophane tape was pressure-bonded and rapidly peeled off. The area of the undercoat layer peeled off at that time was evaluated on a five-point scale.

(6) Adhesion to gelatin; a gelatin layer containing a hardener is applied on the subbed polyethylene terephthalate film obtained in (5), dried and hardened.
(5) Similarly, a cut of 45 ° was made, a cellophane tape was pressed and rapidly peeled off, and the area of the gelatin layer peeled off at that time was evaluated on a five-point scale.

(7) Water resistance of adhesion: The film obtained in (6) was immersed in an aqueous solution of potassium hydroxide having a pH of 10.2 at 35 ° C. for 15 seconds, and the surface was scratched with a pen tip. The area of the peeled gelatin layer was evaluated on a five-point scale.

The criteria of the five-step evaluation indicating the adhesiveness and the water resistance of the adhesion are as follows.

1: The adhesion is very weak and completely peeled off.

2: 50% or more is peeled.

3: About 10 to 50% is peeled off.

4: Adhesive strength is quite strong, less than 10% peel off.

5: Adhesion is very strong and is not peeled off at all.

If the evaluation is 4 or more, it can be considered that the adhesiveness is practically sufficient.

Example 1 36.89 parts by weight of dimethyl terephthalate (DMT), 30.44 parts by weight of dimethyl isophthalate (DMI), 9.85 parts by weight of dimethyl 5-sulfoisophthalate (SIPM), 51.89 parts by weight of ethylene glycol, 0.069 of calcium acetate monohydrate
Parts by weight, a transesterification plate performing 0.023 parts by weight of manganese acetate tetrahydrate under methanol flow at 170 to 220 ° C. under a nitrogen stream, and then performing 0.05 parts by weight of trimethyl phosphate,
0.04 parts by weight of antimony trioxide and 1,4
-Cyclohexanedicarboxylic acid (CHDA) 16.36 parts by weight and polyethylene glycol (number average molecular weight 1,000) 5.10
A part by weight was added thereto, and almost the theoretical amount of water was distilled off at a reaction temperature of 220 to 235 ° C. to carry out esterification. Thereafter, the pressure inside the reaction system was further reduced and the temperature was raised to 280 ° C. and 0.2 mmHg for polycondensation for 3 hours.

When the obtained polyester copolymer was analyzed, the intrinsic viscosity was 0.52 (dl / g). The polyester copolymer was stirred in hot water at 95 ° C. for 3 hours to form a 15% by weight aqueous solution, and then a slightly cloudy 8% by weight aqueous solution obtained by diluting with water was used as an undercoat layer coating solution. A biaxially stretched polyethylene terephthalate film and a gelatin laminated film having an undercoat layer of 0.3 g / m ² by dry weight were applied to a vertically stretched support using the undercoat layer coating solution to obtain the above-mentioned adhesive properties. An evaluation was performed. Table 1 shows the evaluation results.

Examples 2 to 4 Examples 2 to 4 were carried out in the same manner as in Example 1 except that the composition of the polyester copolymer was changed as shown in Table 1.
Was performed. Table 1 shows the results of each evaluation.

Comparative Examples 1 to 9 Comparative Examples 1 to 9 were carried out in the same manner as in Example 1 except that the composition of the polyester copolymer was changed as shown in Table 2.
Was performed. Table 2 shows the results of each evaluation.

Adhesion (1): Adhesion to support Adhesion (2): Adhesion to gelatin Water resistance: Water resistance of adhesion (*): Heat fixing temperature PEG1000: Polyethylene glycol number average molecular weight 1000 PEG2000: Polyethylene glycol number Average molecular weight 2000 PTMG2000: Polytetramethylene glycol number average molecular weight 2
000 DMT: dimethyl terephthalate DMI: dimethyl isophthalate SIPM: dimethyl sodium sulfoisophthalate CHDA: 1,4-cyclohexanedicarboxylic acid ADA: adipic acid EG: ethylene glycol DEG: diethylene glycol As is clear from Tables 1 and 2, in Comparative Example 1 in which polyethylene glycol was not copolymerized, when the heat setting temperature was low, the stress generated during the transverse stretching was not sufficiently relaxed, and the adhesiveness was poor. In Comparative Example 9, although the glass transition temperature was low and the influence of the residual stress was small, the water resistance of the adhesion was poor. Comparative Example 3, which does not contain 1,4-cyclohexanedicarboxylic acid, has poor adhesion to gelatin.

Table 3 shows the evaluation results of the dynamic viscoelasticity of the polyester copolymer forming the undercoat layer for some of the examples and comparative examples. Dynamic viscoelasticity is obtained by Dynamic Mechanical Ana manufactured by Dupont.
The measurement was performed at a heating rate of 5 ° C./min using a lyzer983. The sample was about 15 mm long (between clamps), about 10 mm wide, and about 3.7 mm thick. T1 is the rising temperature related to the glass transition temperature in the tan δ (loss angle) versus temperature curve, T2 is the peak temperature, and T3 is the temperature at which the shear modulus decreased with increasing temperature and became unmeasurable.

As is evident from Table 3, comparing Comparative Examples 1, 7 and 8, it can be seen that the fluidity deteriorates when the sodium sulfoisophthalate component is large. Comparison between Example 1 and Comparative Example 1 shows that copolymerization of a small amount of polyethylene glycol has an effect of reducing the interaction between sodium sulfonate groups and effectively reducing the fluidity. On the other hand, comparing Comparative Examples 5 and 6 with Comparative Example 1, it can be seen that polytetramethylene glycol and diethylene glycol have no effect on improving fluidity. In Comparative Example 9,
Not only T3 but also T1 and T2 are remarkably low. This degrades the water resistance of the bond.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroshi Naito 4-1 Kanebo-cho, Hofu-shi, Yamaguchi Prefecture Kanebo Co., Ltd. (72) Inventor Yoshihiro Wada 1, Sakura-cho, Hino-shi, Tokyo Konica Corporation (56 References JP-A-60-59348 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 63/688

Claims (5)

(57) [Claims] (1) At least the following components (A) and (B):
It is a polyester copolymer comprising (C), (D), (E) and (F), wherein the molar ratio of the component (A) to the component (B) is 30/70 to 70/30, and the component ( C) is 5 to 15 mol% based on the total dicarboxylic acid component, component (D) is 10 mol% or more based on the total dicarboxylic acid component, and component (E) is 50 mol% or more based on the total glycol component. (F) Polyester copolymer characterized in that it is used in an amount of 1 to 10% by weight based on the polyester copolymer. (A) Terephthalic acid and / or its ester-forming derivative (B) Isophthalic acid and / or its ester-forming derivative (C) Dicarboxylic acid having a sulfonic acid salt and / or its ester-forming derivative (D) Alicyclic Dicarboxylic acid and / or ester-forming derivative thereof (E) Ethylene glycol (F) Polyethylene glycol having a number average molecular weight of 400 to 4000 2. A polyester film provided with an undercoat layer on at least one surface of a support, wherein at least one of the undercoat layers contains the polyester copolymer according to claim 1. the film. 3. A polyester film according to claim 2, wherein at least one hydrophilic colloid layer is provided on at least one of the subbing layers containing the polyester copolymer according to claim 1. 4. The polyester film according to claim 3, wherein at least one of said hydrophilic colloid layers contains gelatin. 5. A photographic light-sensitive material having at least one silver halide emulsion layer on the side of a support having an undercoat layer containing the polyester copolymer according to claim 1.