JPH07165955A - Easily-adhesive polyester film - Google Patents

Abstract

PURPOSE:To provide the film excellent in heat resistance, adhesiveness and antistaticity, and useful for magnetic tapes, magnetic cards, printing materials, etc., by disposing an easily-adhesive layer on the surface of a polyester film. CONSTITUTION:A easily-adhesive layer of a polyester comprising (A) a dicarboxylic acid containing >=5mol.% of a phenylindanedicarboxylic acid of formula I (R1, R2, R3 are alkyl) and (B) a hydroxy compound containing 5-100mol.% of a glycol (R is H, CH3; n is 2-60) on one or both surfaces of a polyester film such as polyethylene terephthalate film to produce the objective film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an easily-adhesive polyester film, and more specifically, it is useful as a magnetic tape, a magnetic disk, a magnetic card, a printing material, a packaging material, etc., which is excellent in charging property, heat resistance and adhesive property. It relates to an adhesive polyester film.

[0002]

2. Description of the Related Art Films coated with an aqueous dispersion of polyester have been known in the past, but they are highly hydrophilic and have a low glass transition temperature (hereinafter sometimes referred to as "Tg"), resulting in water resistance and heat resistance. Is low. In particular, a type in which an aqueous polyester dispersion having a sulfonate group or a carboxylate group in the molecule is applied is well known, but the presence of these functional groups makes the applied film easily charged. Further, when a polyester water dispersion in which another hydrophilic group unit is introduced in the molecule is applied, Tg is lowered, heat resistance is lost, and the film is easily blocked.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide an easily adhesive polyester film having excellent adhesiveness and chargeability.

[0004]

The present invention has the following constitution in order to achieve such an object. At least one side of the polyester film is coated with phenylindanedicarboxylic acid 5
Dicarboxylic acid containing more than mol% and glycol of formula I 5
An easily-adhesive polyester film provided with an easily-adhesive layer containing a polyester containing a hydroxy compound in an amount of ˜100 mol% as a main component.

[0005]

[Chemical 2]

The polyester film (hereinafter sometimes referred to as "base film") used in the present invention is, for example, polyethylene terephthalate or polyethylene-2,6.
A polyester film consisting of naphthalene dicarboxylate is particularly preferred. In addition, for example, terephthalic acid-2,6-naphthalenedicarboxylic acid-ethylene glycol copolymer, terephthalic acid-2,6-naphthalenedicarboxylic acid-1,4-butanediol copolymer, polybutylene-2,6-naphthalenediene A polyester film made of carboxylate or the like may be used. Biaxially stretched films of these crystalline polyesters are particularly preferable examples.

In the present invention, an easy-adhesion layer (hereinafter sometimes referred to as "coating") is laminated on such a base film. The polyester constituting the coating has bulky chemical structure peculiar to phenylindanedicarboxylic acid and Taking advantage of the characteristics of hardware due to low mobility of molecular chains,
It has a high g and has good solubility. Therefore, excellent water resistance,
It has heat resistance and adhesiveness, and can be dispersed in water without containing a large amount of sulfonate group or carboxylate group.

The polyester used as a component constituting the coating film of the present invention is a polyester composed of a dicarboxylic acid component and a hydroxy component, and phenylindanedicarboxylic acid (the following formula II) is used as the dicarboxylic acid component.

[0009]

[Chemical 3]

It is necessary to have 5 to 100 mol%, but 20 to 100 mol% is preferable, and 40 to 100 mol% is particularly preferable. If the phenylindanedicarboxylic acid content is less than 5 mol%, the solubility of the polyester will be poor and water dispersion will not be easy. R ₁ , R ₂ and R in formula II
_{Although a} lower alkyl group is used as ₃ , a methyl group is preferable.

Acids other than phenylindanedicarboxylic acid include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid and 4,4 '.
Examples thereof include diphenyldicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, pyromellitic acid, and dimer acid. Two or more kinds of these components can be used. Further, unsaturated polybasic acids such as maleic acid, fumaric acid and itaconic acid, and hydroxycarboxylic acids such as p-hydroxybenzoic acid and p- (β-hydroxyethoxy) benzoic acid can be used in small proportions together with these components. . The ratio of the unsaturated polybasic acid component and the hydroxycarboxylic acid component is at most 10 mol%, preferably 5 mol% or less.

When an ester-forming derivative of a polybasic acid is used as a starting material, a lower alkyl ester, particularly a methyl ester can be preferably exemplified as the ester-forming derivative.

The polyester used as a component constituting the coating film of the present invention has a hydroxy component (the following formula I).

[0014]

[Chemical 4]

The compound (5) is 5 to 100% by weight based on the total weight of the hydroxy compound. When the proportion of the hydroxy compound is less than 5% by weight, the hydrophilicity of the polyester is insufficient and it is difficult to obtain a stable aqueous dispersion.

The hydroxy compound has the formula I in which n is from 2 to 6
0 range, for example, diethylene glycol, propylene glycol, triethylene glycol,
Examples thereof include tetraethylene glycol and polyethylene glycol having an average molecular weight of 800. If n of the formula I exceeds 60, the blocking resistance decreases. Of these hydroxy compounds, diethylene glycol and triethylene glycol are preferred.

Examples of polyhydric hydroxy compounds other than the above hydroxy compounds are ethylene glycol, 1,4-butanediol, neopentylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol,
Xylylene glycol, dimethylolpropionic acid, glycerin, trimethylolpropane, poly (ethylene oxide) glycol, poly (tetramethylene oxide)
Examples thereof include glycol and bisphenol A alkylene oxide adducts. Two or more kinds of these components can be used.

Further, if necessary, a small amount (1 mol% or less, particularly 0.5 mol% or less) of a sulfonate group is introduced by using 5-Nasulfoisophthalic acid or the like in order to impart hydrophilicity to the polyester molecule. It is also possible to introduce a small amount (3 mol% or less, particularly 1 mol% or less) of a carboxylate group by carboxylating with dimethylolpropionic acid, succinic anhydride, butanetetracarboxylic dianhydride to form a salt. .

The polyester thus obtained may be dissolved or dispersed in water or hot water, or may be once dissolved in an organic solvent and then added with water to disperse, and then the solvent may be removed to obtain an aqueous solution.

In the present invention, a coating agent containing polyester (which may hereinafter be referred to as a "coating solution") that constitutes the above coating film is applied to the base film and laminated, but the coating solution may contain other resins. Further, an antistatic agent, a lubricant, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant and the like may be added. The water-based coating liquid may contain an organic solvent, and the solvent-based coating liquid may contain water. The concentration of the coating liquid is arbitrary, but 1 to 12% by weight, particularly 2 to 6%
Weight percent is preferred.

The base polyester film may be an unstretched film, a uniaxially stretched film or a biaxially stretched film. Of these, apply the coating solution to the uniaxially stretched film,
A method of further stretching and heat treatment after drying is preferable.

As a method of applying the coating liquid, any method such as a roll coater or a die coater can be used.

The coating thickness is arbitrary, but is 0.01 to 2 μm.
m is preferred. The application is applied to one side or both sides.

[0024]

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

1. Adhesiveness The following coating composition for evaluation (magnetic coating composition) was coated on the coated surface of the polyester film of the sample with a Meyer bar so that the thickness after drying was about 4 μm, and dried at 100 ° C. for 3 minutes.
Then aged at 60 ° C for 24 hours, then width 1
Scotch tape (No. 600, manufactured by 3M Co., Ltd.) having a length of 2.7 mm and a length of 150 mm is adhered to the film coated surface so that air bubbles do not enter, and the top of this is JIS C2701 (1975)
After being leveled with the manual load roll described, and making it adhere, cut into the tape width. The adhesive force when the film-coated surface and the paint layer of the sample thus prepared was peeled by 180 degrees was measured.

[Evaluation paint] In terms of solid content, urethane resin (Nippon Polyurethane / Nipporan 2304) 25 parts PVC / vinyl acetate resin (Sekisui Chemical / ESLEC A) 50 parts Dispersant (RIKEN Vitamin / Resion P) 1 part Magnetic agent (manufactured by Toda Chemical Co., Ltd., CTX-860) 500 parts was dissolved in a mixed solvent of methyl ethyl ketone / toluene / cyclohexanone to obtain a 40% liquid, which was dispersed for 2 hours by a sand grinder. After that, 25 parts (corresponding to solid content) of the cross-linking agent Coronate L is added and well stirred to obtain a magnetic coating material.

2. Antistatic primer coating film (10μm × 500mm × 30
00m) rolls in an atmosphere of 23 ° C x 75% RH for 15
The film was rewound at a speed of 0 m / min, and the amount of peeling charge of the roll was measured using a digital test electrical measuring instrument Model-203 manufactured by Hugle Electronics.

3. Second-order transition temperature DuPont Thermal Analyst 200
It was measured with a 0 type differential calorimeter at a temperature rising rate of 20 ° C./min.

4. Intrinsic viscosity The viscosity of the solution with the orthochlorophenol solvent is 35 ℃
It was measured and determined at.

Example 1 An unstretched film of polyethylene terephthalate (A) having an intrinsic viscosity [η] of 0.63 was stretched 3.5 times in the machine direction, and then phenylindanedicarboxylic acid (formula III) was formed on one side.

[0031]

[Chemical 5]

[90 mol%]-isophthalic acid [5 mol%]-terephthalic acid [5 mol%]-diethylene glycol [75 wt%]-ethylene glycol [25 wt%]
Copolyester consisting of (hereinafter referred to as "K-1")
A 4% aqueous dispersion of a composition consisting of 90% by weight and 10% by weight of polyoxyethylene nonylphenyl ether was applied with a roll coater. Then, after drying the uniaxially stretched film coated with the water dispersion, stretched 3.5 times in the transverse direction,
Further, it was heat-treated at 220 ° C. to obtain a laminated film having a thickness of 10 μm. The coating thickness of this film is 0.05μ
It was m. The characteristic values of this film are shown in Table 1.

[Example 2] A film obtained in the same manner as in Example 1 except that a base film of polyethylene-2,6-naphthalene dicarboxylate (B) having an intrinsic viscosity [η] of 0.63 was used. The characteristic values are shown in Table 1.

Example 3 Except that a base film of polyethylene terephthalate (containing 0.4% by weight of calcium carbonate having an average particle size of 0.1 μm) (C) having an intrinsic viscosity [η] of 0.61 was used. Table 1 shows the characteristic values of the film obtained in the same manner as in Example 1.

[Comparative Example 1] Table 1 shows characteristic values of a film obtained in the same manner as in Example 1 except that the polyester aqueous dispersion was not coated.

As is clear from Table 1, the film of the present invention has good adhesiveness and chargeability, whereas the film of Comparative Example 1 has significantly poor adhesiveness.

[Examples 4 to 11 and Comparative Example 2] Table 1 shows the results when the copolymerized polyester in the polyester aqueous dispersion or the coating thickness was changed to be applied to various base films.

As is clear from Table 1, the film of the present invention has good adhesiveness and chargeability, whereas the film of Comparative Example 2 has remarkably poor chargeability and insufficient adhesiveness.

[0039]

[Table 1]

Comparative Example 3 Except that terephthalic acid [90 mol%] / isophthalic acid [10 mol%] / ethylene glycol [70 wt%] / diethylene glycol [30 wt%] was used as the copolyester. As a result of attempting coating in the same manner as in No. 1, the copolymerized polyester was inferior in solubility in a solvent and an aqueous dispersion could not be obtained, and coating could not be performed.

[Comparative Example 4] Compound of formula III [40 mol%]-isophthalic acid [60 mol%]-Compound of formula I (R
= CH ₃ , n = 65) [90% by weight] / diethylene glycol [10% by weight] except that the copolyester is coated, the film produced in the same manner as in Example 1 is likely to cause blocking on the coated surface. The coated surface and the non-coated surface are overlapped with each other at 50 ° C. × 50 kg / cm ²
When left for 3 hours under the above conditions, sticking occurred and the coating layer was broken during peeling, which was not practical.

[0042]

The coated film thus obtained has excellent adhesiveness and is hardly charged, and is useful for magnetic tapes, magnetic disks, magnetic cards, printing materials, packaging materials and the like.

Claims (1)

[Claims] 1. A dicarboxylic acid containing 5 mol% or more of phenylindanedicarboxylic acid and 5 to 100 mol% of a glycol of the formula I on at least one side of a polyester film.
An easily-adhesive polyester film provided with an easily-adhesive layer containing a polyester containing a hydroxy compound as a main component. [Chemical 1]