JP2825719B2 - Coating composition, easy-adhesive polyester film coated with the same, and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a composition for coating,
More particularly, the present invention relates to a coating composition capable of forming an easily adhesive coating film having excellent water resistance, excellent blocking resistance, and excellent abrasion resistance. The present invention relates to an easily adhesive polyester film useful for packaging materials, magnetic cards, magnetic tapes, magnetic disks, printing materials and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Thermoplastic polyesters such as polyethylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene naphthalate or copolymers thereof, or blends thereof with a small proportion of other resins, etc. A polyester film obtained by melt-extruding, biaxially stretching, and heat setting is excellent in mechanical strength, heat resistance, chemical resistance, and the like, and is used in various industrial fields. However, since the surface is highly crystallographically oriented, there is a problem that the acceptability of paints, adhesives, inks and the like is poor.

As a method for improving the receptivity of the polyester film surface, there is a method in which a primer layer (undercoat layer) made of a synthetic resin is provided on the film surface in advance, and a thin surface layer different from the base film is formed. The formation of the primer layer is carried out by applying an organic solvent solution of a synthetic resin or, preferably, an aqueous solution, and applying the solution.

As an aqueous liquid for forming the primer layer, for example, JP-A-60-248232 and JP-A-1
In JP-A-236247, an aqueous solution of a polyester polymer having a substituent of a sulfonic acid derivative is used. An aromatic dicarboxylic acid or an aliphatic dicarboxylic acid is used as an acid component of the polymer.

However, when, for example, naphthalenedicarboxylic acid is used as the acid component of the polymer, the secondary transition point (Tg) of the polymer is increased and the heat resistance is improved, but the flexibility is lost and the polymer becomes brittle. On the other hand, when adipic acid is used, the polymer is flexible and has high flexibility, but the Tg is lowered and the polymer has low heat resistance. And the primer layer using the polymer, in the former case, has good water resistance and blocking resistance, but has poor abrasion resistance related to the brittleness of the polymer, while in the latter case, the abrasion resistance is poor. Good, but lacks water resistance and blocking resistance.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a polyester capable of forming an easily adhesive coating film having excellent water resistance and blocking resistance, and further having excellent abrasion resistance. An object of the present invention is to provide a polyester film and a method for producing the same.

[0007]

The present invention has the following configuration in order to achieve the above object. 1. (A) a repeating unit substantially represented by the formula (a)

[0008]

Embedded image [Wherein R ₁ is

[0009]

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(In the formula (b), X
Represents an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, an aryl group having 6 to 12 carbon atoms, or halogen. n represents 0, 1 or 2. ) From 20 to 100
Mole%, p-phenylene group, m-phenylene group,
4,4'-diphenylene group, 2,6-naphthylene group and

[0011]

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(In the formula (c), M represents an alkali metal.)
80% by mole, and R ₂ is

[0013]

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20 to 100 mol%, and 0 to 80 mol% of an alkylene group and / or cycloalkylene group having 2 to 12 carbon atoms. And a coating composition comprising: (B) water.

2. An easily-adhesive polyester film obtained by applying the coating composition of the above item 1 on at least one surface of the polyester film and drying the composition.

3. The above-mentioned coating composition is applied to at least one surface of the polyester film before the orientation crystallization is completed, and then dried, stretched, and heat-set to complete the orientation crystallization. Method for producing conductive polyester film.

4. The coating composition of 1 above is applied to at least one surface of the polyester film uniaxially stretched in the longitudinal direction, then dried, stretched in the transverse direction, further stretched in the longitudinal direction, and optionally stretched in the transverse direction. And a heat-setting treatment.

In the present invention, R ₁ of the polymer substantially consisting of the repeating unit represented by the formula (a) is 20 to 100 mol%, preferably 40% by mol, of the structure represented by the formula (b).
-100 mol%, more preferably 60-100 mol%
And at least one selected from p-phenylene group, m-phenylene group, 4,4′-diphenylene group, 2,6-naphthylene group and the structure represented by the formula (c) as 0 to 80 %, Preferably 0 to 60 mol%, more preferably 0 to 40 mol%.

R ₂ has a structure represented by the formula (d) in an amount of 20 to 100 mol%, preferably 40 to 100 mol%, more preferably 60 to 100 mol%. 0 to 80 mol%, preferably 0 to 6 mol% of 2 to 12 alkylene groups and / or cycloalkylene groups
It has 0 mol%, more preferably 0 to 40 mol%.

The polyester substantially consisting of a repeating unit represented by the formula (a) is a polyester containing a repeating unit represented by the following formula (I) as a main component.

[0021]

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[In the formula (I), X is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, and 6 to 6 carbon atoms.
Represents 12 aryl groups or halogens. n represents 0, 1 or 2. ]

In the formula (I), X is an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms,
2 represents an aryl group or a halogen. More specifically, a methyl group, an ethyl group, a propyl group or the like as an alkyl group, a cyclopentyl group or a cyclohexyl group as a cycloalkyl group, a phenyl group, a tolyl group, a naphthyl group as an aryl group, and chlorine as a halogen can be exemplified. n is 0, 1 or 2.

The polyester has a structure represented by the above formula (I) as a main component, and examples of the subcomponent include a repeating unit represented by the following formula (II) and / or (III).

[0025]

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In the formulas (II) and (III), X and n
Is the same as in the above formula (I), and Y represents a divalent aromatic residue. R ₃ represents an alkylene group having 2 to 12 carbon atoms or a cycloalkylene group. Specific examples of Y include a p-phenylene group, an m-phenylene group, a 4,4′-diphenylene group, a 2,6-naphthylene group,

[0027]

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[M represents an alkali metal, and examples thereof include Na and K. ] Etc. can be exemplified.

Further, as R ₃ , specifically, an ethylene group,
Trimethylene group, tetramethylene group, propylene group,

[0030]

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And the like. Further, the polyester may further contain a structure represented by the following (IV) or (V) as a subordinate component.

[0032]

Embedded image —OC—Z—CO—OR ₄ —O— (IV) —O—Z—CO— (V) [In the formulas (IV) and (V), Z is a divalent fragrance. Indicates a group residue. R ₄ represents an alkylene group having 2 to 12 carbon atoms and a cycloalkylene group. Specific examples of Z include p-phenylene group, m-phenylene group, 4,4'-diphenylene group, 2,6-naphthylene group,

[0033]

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[M represents an alkali metal, and examples thereof include Na and K. ] Can be exemplified. R ₄ represents an alkylene group having 2 to 12 carbon atoms and a cycloalkylene group, specifically, an ethylene group, a trimethylene group, a tetramethylene group, a propylene group,

[0035]

Embedded image Etc. can be exemplified.

The formulas (II), (III), (IV),
The other kinds of structures represented by (V) can be used alone or in combination of a plurality.

That is, in the polyester comprising a repeating unit represented by the formula (a), the acid component constituting the polymer is 2,3-bis (4-carboxyphenyl) quinoxaline, terephthalic acid, isophthalic acid, 2,6-naphthalene The dicarboxylic acid, 4,4'-diphenyldicarboxylic acid and an aromatic dicarboxylic acid containing a dicarboxylic acid having a sulfonic acid metal base, and the 2,3-
Bis (4-carboxyphenyl) quinoxaline is 20 to 100 mol% of the total acid component, and the glycol component constituting the polymer is neopentylene glycol, alkylene glycol having 2 to 12 carbon atoms, and cycloalkyl having 2 to 12 carbon atoms. Mainly composed of alkylene glycol, and
Neopentylene glycol is 20-
100% by mole of polyester.

The polyester substantially consisting of the repeating unit represented by the formula (a) is obtained by combining a polybasic acid mainly composed of 2,3-bis (4-carboxyphenyl) quinoxaline or an ester-forming derivative thereof with a polyol compound. It can be produced by reacting. Here, as the ester-forming derivative, lower alkyl esters such as methyl ester and ethyl ester can be preferably used. As a method for producing the polyester, a conventionally known polymerization method in the art such as a transesterification polymerization method or a direct polymerization method can be used.

2,3-bis (4-carboxyphenyl)
Polybasic acids other than quinoxaline include terephthalic acid,
Isophthalic acid, 2,6-naphthalenedicarboxylic acid, 4,
4'-diphenyldicarboxylic acid and the like can be exemplified. These may be used in combination of two or more.

In the polyester substantially consisting of the repeating unit represented by the formula (a), a small proportion of hydroxycarboxylic acid can be used in addition to the above polybasic acid. P-hydroxybenzoic acid as the hydroxycarboxylic acid,
Examples thereof include m-hydroxybenzoic acid, p- (β-hydroxyethoxy) benzoic acid, and ε-hydroxycaproic acid. The proportion of the hydroxycarboxylic acid component is preferably 10 mol% or less, more preferably 5 mol% or less of the total acid component.

Examples of the polyol compound include ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexanediol, and 1,4-cyclohexanedimethanol. it can. Two or more of these can be used.

The polyester substantially consisting of a repeating unit represented by the formula (a) is, for example, an organic sulfonate, a carboxylate, diethylene glycol, polyethylene glycol, dimethyl 5- [N- (p-trisulfonyl) Potassioiminosulfonyl] It is preferable to copolymerize a hydrophilic group-containing compound such as 1,3-phenylenedicarboxylate, dimethyl 3,3 '-(sodiiominodisulfonyl) dibenzoate, thereby obtaining an aqueous liquid, It is particularly advantageous to make an aqueous emulsion. Usually, tricarboxylic or more functional carboxylic acid is used for the introduction of such a carboxylic acid salt. However, since the carboxylic acid is liable to be gelled due to branching in the polymerization step, it is desirable to reduce the copolymerization ratio. In this regard, introduction of hydrophilicity with a sulfonate, diethylene glycol, polyethylene glycol or the like does not cause a problem in the case of a carboxylate, and is more advantageous.

In order to introduce a sulfonate group into a polyester molecule, for example, 5-Na sulfoisophthalic acid, 5
-Ammonium sulfoisophthalic acid, 4-Na sulfoisophthalic acid, 4-methylammonium sulfoisophthalic acid, 2-Na sulfoterephthalic acid, 5-K sulfoisophthalic acid, 4-K sulfoisophthalic acid, 2-K sulfoterephthalic acid, Na It is preferable to use a sulfonic acid alkali metal salt compound such as sulfosuccinic acid or a sulfonic acid amine salt compound. The polycarboxylic acid or polyhydric alcohol having a sulfonic acid salt group preferably accounts for 0.5 to 20 mol%, more preferably 1 to 18 mol%, of the total acid component or total alcohol component.

In order to introduce a carboxylic acid group into the polyester molecule, for example, trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, dimethylolpropionic acid, etc. Can be used.

The polyester substantially consisting of the repeating unit represented by the formula (a) has a high secondary transition point due to its bulky property based on the specific structure of the diphenylquinoxaline component and its hard property due to low molecular chain mobility. Tg) and excellent flexibility. This secondary transition point is
It is usually 70 ° C. or higher, preferably 90 ° C. or higher.

The reduced viscosity of the polyester measured in a phenol / tetrachloroethane (1,1,2,2-tetrachloroethane) mixed solvent (weight ratio 60/40) at a concentration of 1.2 g / dl at a temperature of 35 ° C. Is 0.3 or more. When the reduced viscosity is less than 0.3, heat resistance and mechanical properties become insufficient. The reduced viscosity is preferably 0.4 or more, particularly preferably 0.5 or more, and its upper limit is about 2.0.

The coating composition of the present invention is produced by dispersing the above-mentioned polyester substantially consisting of a repeating unit represented by the formula (a) in water.

The dispersion method is not particularly limited. For example, the above-mentioned polyester is compatible with water, dissolved in an organic solvent having a boiling point lower than that of water, diluted with water, and then the organic solvent is heated. A method of distilling off is preferably used. Examples of the organic solvent used here include tetrahydrofuran and acetonitrile.

In the composition, 0.5 to 30% by weight, preferably 1 to 20% by weight of a polyester mainly composed of a repeating unit represented by the formula (a) is added to the whole composition.
Disperse. The viscosity of the composition is between 1 and 200 centipoise, preferably between 2 and 100 centipoise.

If necessary, a surfactant, an antistatic agent, a filler, an ultraviolet absorber, a lubricant, a coloring agent, and the like may be added to the coating composition. In order to improve coatability, a water-soluble organic solvent may be used in a small proportion (for example, 30% or less). As the organic solvent, methanol,
Lower alcohols such as ethanol, propanol, butanol and the like are preferred.

When the coating composition of the present invention is used, a thin film having excellent water resistance, blocking resistance, abrasion resistance and easy adhesion can be applied on the polyester film surface. Therefore, according to the present invention, it is possible to provide an easily-adhesive polyester film in which a primer layer composed of a thin film of the coating composition is applied on at least one surface of the polyester film.

Such a primer layer is preferably formed by applying a coating composition during the production of the polyester film. For example, it is preferable to apply the coating composition to at least one surface of the polyester film before the process of oriented crystallization is completed. Next, drying, stretching and heat-setting are performed to complete the oriented crystallization, whereby an easily adhesive polyester film can be produced. Here, the polyester film before the completion of the crystal orientation is an unstretched film obtained by heat-melting the polymer to form a film as it is: a uniaxial film in which the unstretched film is oriented in either the longitudinal direction or the transverse direction. Stretched film: Further, a film stretched and oriented at a low magnification in two directions of a longitudinal direction and a transverse direction (a biaxially stretched film before being finally stretched in a longitudinal direction or a transverse direction to complete oriented crystallization) and the like. Including. Among them, a film uniaxially stretched in the longitudinal direction is preferable.

Therefore, the coating composition is applied to at least one side of the polyester film uniaxially stretched in the longitudinal direction, and then dried, stretched, and heat-set to complete orientation crystallization to produce an easily adhesive polyester film. And a coating composition is applied to at least one surface of the polyester film stretched uniaxially in the longitudinal direction, then dried, stretched in the transverse direction, further stretched in the longitudinal direction, and optionally stretched in the transverse direction. And a method of producing an easily-adhesive polyester film by subjecting it to a heat-setting treatment. As conditions for producing the polyester film, conventionally known or used conditions can be used.

The polyester constituting such a polyester film is 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 polyester include polyethylene terephthalate, polyethylene isophthalate, polybutylene terephthalate, poly (1,4-cyclohexylene dimethylene terephthalate), polyethylene-2,6-naphthalenedicarboxylate, and the like. A coalescence or a blend of these with a small proportion of another resin is also included.

The easily adhesive polyester film of the present invention is preferably applied to the unstretched or at least uniaxially stretched film before completion of the crystal orientation, followed by longitudinal stretching and stretching. It is preferable to manufacture by a so-called in-line coating method in which transverse stretching and heat setting are performed.

At this time, in order to smoothly apply a coating film on the surface of the polyester film before the orientation crystallization process is completed, the film surface is subjected to a corona discharge treatment as a preliminary treatment, or It is preferable to use a chemically inert surfactant together with the composition.

Such a surfactant promotes wetting of a polyester film so that the surface tension of the composition can be reduced to 50 dyne / cm or less. For example, polyoxyethylene alkyl phenyl ether, polyoxyethylene-fatty acid Examples thereof include anionic and nonionic surfactants such as esters, sorbitan fatty acid esters, glycerin fatty acid esters, fatty acid metal soaps, alkyl sulfates, alkyl sulfonates, and alkyl sulfosuccinates. The composition includes those in which the polyester is dissolved, those in which the aqueous polyester is suspended and dispersed in a colloidal state, and the like.

The amount of coating is preferably about 0.5 to 20 g, and more preferably about 1 to 10 g per m ² of the running film. In other words, in the finally obtained biaxially stretched film, about 0.001 to 1 per m ^{2 is} applied to one surface of the film.
g, and preferably about 0.005 to 0.3 g solids.

As a coating method, any known coating method can be applied. For example, a roll coating method, a gravure coating method, a roll brushing method, a spray coating method, an air knife coating method, an impregnation method, a curtain coating method, or the like may be applied alone or in combination.

According to the preferred production method of the present invention,
The above composition is preferably applied to a polyester film immediately after being subjected to longitudinal uniaxial stretching, and then the film is guided to a tenter for transverse stretching and heat setting after preheating.

At this time, the applied composition is sufficiently dried in the preheating zone, but is dried so that a small amount of water remains. Next, the uniaxial film provided with the primer layer is heated and transversely stretched and then heat-set by a high-temperature treatment.

Conditions for oriented crystallization of the polyester film,
For example, stretching, heat setting, and the like can be performed under conditions conventionally accumulated in the art. For example, 80-140
The film is stretched at 2.5 to 6 times C and heat set at 180 to 240 C for 5 seconds.

[0063]

By using the coating composition of the present invention, a thin film having excellent water resistance, blocking resistance, abrasion resistance and easy adhesion can be applied on the polyester film surface.

The thus-obtained easily-adhesive polyester film has a high adhesive strength, a high abrasion resistance, excellent blocking resistance, and excellent water resistance. Therefore, for example, a magnetic card, a magnetic tape, a magnetic disk, a printing material, a graphic material, Useful for photosensitive materials and the like.

[0065]

The present invention will be described in more detail with reference to the following examples. In addition, the part in an Example means a weight part. Each characteristic value was measured by the following method.

1. Adhesiveness (A) Magnetic paint The evaluation paint is applied to a sample polyester film using a Meyer bar so that the thickness after drying becomes about 4 μm.
Dry at 00 ° C. for 3 minutes. Thereafter, aging was performed at 60 ° C. for 24 hours. A 600 (manufactured by 3M) width of 12.7 mm and a length of 15 cm are adhered so as not to contain air bubbles. The strength at 180 ° peeling is measured.

[Evaluation paint] Urethane resin Nipporan 2304 (manufactured by Nippon Polyurethane) 25 parts PVC / acetate resin Esrec A (manufactured by Sekisui Chemical) 50 parts Dispersant Ratio P (manufactured by Riken Vitamin) 1 part in terms of solids Agent CTX-860 (manufactured by Toda Chemical Co., Ltd.) (500 parts) is dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to make a 40% solution, and dispersed by a sand grinder for 2 hours. Thereafter, 25 parts (in terms of solid content) of coronate L as a cross-linking agent are added and stirred well to obtain a magnetic paint.

(B) UV Ink A UV-curable printing ink (flash dry FDO Beni AP manufactured by Toyo Ink) was placed on a sample polyester film.
N) after printing with an RI tester (made by Mei Seisakusho)
Curing was performed using a medium pressure mercury lamp (80 W / cm, single-lamp type: manufactured by Nippon Battery) UV curing device, and a 7.0 μm thick UV
Form an ink layer.

A cut is made on the UV ink layer with a cutter knife, a cellophane tape is adhered, 90 ° peeling is performed, and the peeled state is displayed in five stages (good: 5 ← → 1: evil).

(C) Offset Ink An ink HS-OS manufactured by Kuboi Ink Co., Ltd. was applied on a sample polyester film to a thickness of 10 μm (Dry) using a geser, dried at 120 ° C. for 1 minute, and further dried at room temperature for 1 hour. After sun-drying, make a cut on the ink with a cutter knife, and then attach cellophane tape.
90 ° peeling is performed, and the peeled state is displayed in five stages (good: 5 ← → 1: bad).

(D) Screen Ink Ink Sericol EG manufactured by Teikoku Ink Co., Ltd. was applied to a thickness of 10 μm (Dry) on a sample polyester film using a geser and air-dried at room temperature for one day. A notch cut is made on the ink with a cutter knife, and cellophane tape is adhered, and 90 ° regular peeling is performed, and the peeled state is displayed in five stages (good: 5 ← → 1: bad). The five-grade evaluation of the above inks follows the criteria in Table 1.

[0072]

[Table 1]

2. Blocking resistance The treated and untreated surfaces of the two films were overlapped, and a pressure of 6 kg / cm ² was applied to the film under an atmosphere of 50 ° C. × 70% RH.
Peel after 7 hours and evaluate by the peel force (5cm
G per width).

3. Surface slipperiness The slipperiness of the treated surface and the untreated surface was measured using a slippery measuring tester manufactured by Toyo Tester Co., at a temperature of 23 ° C and a humidity of 60% RH.
In Table 1, the static friction coefficient measured under a load of 1 kg is shown.

4. Abrasion resistance A coated surface of a roll film having a width of 1/2 inch is applied to a fixing pin, and the film is run at a speed of 2 m / min. After 15 minutes, deposits on the fixing pin are observed and evaluated according to the following criteria. ：: Almost no sediment observed △: Slight trace of adhesion ×: Many

5. Secondary transition point (Tg) of polymer Measured at a heating rate of 10 ° C./min using DSC.

6. Intrinsic viscosity of the polymer The polymer was dissolved in a phenol / 1,1,2,2-tetrachloroethane mixed solvent (weight ratio 60/40) at a concentration of 1.2 g.
/ Dl at a temperature of 35 ° C.

[0078]

Example 1 40 parts of 2,3-bis (4-carbomethoxyphenyl) quinoxaline, neopentylene glycol 2
0 parts, dimethyl 5-Na sulfoisophthalate (Na-S
IA) 0.9 part and tetrabutyl titanate 0.01 part were placed in a reaction vessel equipped with a stirrer and a rectification column, and
The mixture was heated to ℃ to distill off methanol produced by the transesterification reaction. After 6 parts of methanol had been distilled off, the reaction mixture was replaced in a reaction vessel equipped with a stirrer and a vacuum distillation system, and at 290 ° C. for 30 minutes in a nitrogen stream under normal pressure, and then for 15 minutes under reduced pressure of about 20 mmHg. The reaction was further performed under a reduced pressure of 0.5 mmHg for 80 minutes.

The obtained polymer was pale yellow and transparent, had an intrinsic viscosity of 0.70 and a Tg of 175 ° C.

This polymer was dissolved in tetrahydrofuran, water was added and dispersed, and then tetrahydrofuran was distilled off to obtain an aqueous dispersion having a polymer concentration of 4% by weight. Further, 90 parts by weight of the aqueous dispersion and a 4% concentration of a surfactant (Nonion NS208.5; manufactured by NOF Corporation) aqueous solution 10
The coating composition was prepared by mixing the mixture with parts by weight.

A polyethylene terephthalate (including a lubricant) having an intrinsic viscosity of 0.62 was melt-extruded on a rotary cooling drum maintained at 20 ° C. to form an unstretched film, which was stretched 3.6 times in the machine axis direction. The coating composition was roll coated. Then 130 ° C in the horizontal direction
Stretched 3.7 times, and heat-treated at 216 ° C to a thickness of 75μ.
m of the primer-coated biaxially oriented polyester film was obtained. The coating thickness was 0.04 g / m ² (Dry).

Table 2 shows the properties of the coated surface of the obtained film, easy adhesion of ink, surface slippage, blocking resistance and the like.

[0083]

[Comparative Example 1] For comparison, thickness 7 without primer treatment
The same evaluation as in Example 1 was performed using a 5 μm polyethylene terephthalate film. Table 2 shows the results.

[0084]

[Table 2]

[0085]

Examples 2 to 4 In the same manner as in Example 1, 90 parts by weight of a liquid obtained by dispersing the polyester shown in Table 3 at a ratio of 4% by weight in a medium shown in Table 3 containing water as a main component was prepared. Was mixed with 10 parts by weight of a 4% by weight aqueous solution of a surfactant shown in Table 1 to prepare a coating composition.

A polyethylene terephthalate having an intrinsic viscosity of 0.62 was melt-extruded onto a rotating cooling drum maintained at 20 ° C. to form an unstretched film, which was stretched 3.7 times in the machine axis direction. The composition was roll coated. Next, 101
Stretched 3.9 times at ℃, heat-treated at 216 ℃, thickness 10
A .mu.m primer-coated biaxially oriented polyester film was obtained. The coating thickness was 0.04 g / m ² (Dry).

Table 4 shows the properties of the coated surface of the obtained film, easy adhesion of magnetic paint, surface slippage, abrasion resistance, blocking resistance, and the like.

[0088]

[Comparative Example 2] Thickness 1 without primer treatment for comparison
The same evaluation as in Example 2 was performed using a 0 μm polyethylene terephthalate film. Table 4 shows the results.

[0089]

Comparative Examples 3 and 4 The polyester coating compositions shown in Table 3 were applied in the same manner as in Example 2 to obtain a primer-coated biaxially oriented polyester film.

The same evaluation as in Example 2 was performed using the obtained film, and the results are shown in Table 4.

[0091]

[Table 3]

[0092]

[Table 4]

As is clear from Table 4, the films of the examples are films having excellent adhesion, blocking resistance and abrasion resistance.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08J 7/04 CFD C08J 7/04 CFD C08L 67/02 C08L 67/02 // B29K 67:00 B29L 9:00 (58) Int.Cl. ⁶ , DB name) C09D 167/00-167/08 B29C 55/00-55/20 B32B 27/36 C08G 63/00-63/91 C08J 7/04 C08L 67/00-67/08 REGISTRY (STN)

Claims (6)

(57) [Claims] (A) a repeating unit substantially represented by the formula (a): Wherein R ₁ is (In the formula (b), X is a group having 1 to 1 carbon atoms)
6, an alkyl group, a cycloalkyl group having 5 to 10 carbon atoms,
It represents an aryl group having 6 to 12 carbon atoms or halogen. n
Represents 0, 1 or 2. ) Having from 20 to 100 mol%,
p-phenylene group, m-phenylene group, 4,4'-diphenylene group, 2,6-naphthylene group and (In the formula (c), M represents an alkali metal.) Having at least one 0 to 80 mole% selected from the group consisting of, R ₂ is embedded image 20 to 100 mol% of a structure represented by
0 to 80 mol% of an alkylene group and / or a cycloalkylene group of from 12 to 12. And a coating composition comprising: (B) water. 2. The coating composition according to claim 1, which contains 0.5 to 30% by weight of a polyester substantially consisting of a repeating unit represented by the formula (a). 3. An easily-adhesive polyester film obtained by applying the coating composition according to claim 1 on at least one surface of the polyester film and drying. 4. The coating composition according to claim 1, which is applied to at least one surface of the polyester film before the orientation crystallization is completed, and then subjected to drying, stretching, and heat setting to complete the orientation crystallization. A method for producing an easily adhesive polyester film, comprising: 5. The method for producing an easily-adhesive polyester film according to claim 4, wherein the polyester film before the orientation crystallization is completed is a polyester film uniaxially stretched in the longitudinal direction. 6. A polyester film stretched uniaxially in the longitudinal direction is coated on at least one side with the coating composition according to claim 1, dried, stretched in the transverse direction, and stretched again in the longitudinal direction. A method for producing an easily adhesive polyester film, wherein the film is subjected to re-stretching in the transverse direction by a heat treatment.