JPH07101016A - Laminated polyester film - Google Patents

Abstract

PURPOSE:To obtain a low-cost polyester film having no electrostatic failure under a low moisture enviromnent by laminating a layer containing polyaniline containing a sulfonic group on one surface of the polyester film. CONSTITUTION:At least one surface of a longitudinally oriented polyester film is coated with an aqueous solution of polyaniline containing a sulfonic group by a coating method, and dried with hot air. Then, it is laterally oriented and heat set to obtain a biaxially oriented laminated polyester film. Further, for a utilization in which adhesive properties of the polyester film of a base material and a magnetic layer, other laminate are strongly required, at least one surface of the polyester film is coated and laminated with a mixture of the aqueous solution of the polyaniline containing the sulfonic group and anionic groupcontaining resin compound. A surface resistance value of the surface laminated with the polyaniline containing the sulfonic group is set to 10<7>-10<11>OMEGA/ under an environment of 23 deg.C and relative humidity of 15%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polyester film, and more particularly to a polyester film having a polyaniline component containing at least a sulfonic acid group laminated on one side of the polyester film and having good antistatic properties.

[0002]

2. Description of the Related Art Polyester films are excellent in heat resistance, dimensional stability, mechanical strength, etc. and are used in a large amount and in a wide range. However, it has been pointed out that one of the obstacles in the use of the polyester film is due to static electricity, and there is a demand for an inexpensive polyester film which is free from electrostatic disorders, especially in a low humidity environment.

[0003]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of earnest research focusing on the above-mentioned circumstances, and the purpose thereof is to make full use of the original advantages of the polyester film, and at the same time, to avoid the drawback of static electricity. It is to provide an inexpensive polyester film that overcomes obstacles.

[0004]

The above object can be achieved by a laminated polyester film characterized in that a polyaniline containing a sulfonic acid group is laminated on at least one side of a polyester film.

Further, for example, in applications where adhesion between a base polyester film and a magnetic layer or other laminates is strongly required, at least one layer of anionic group-containing polyester, polyurethane or polyacrylic acid ester is coated. It is preferable to use a laminated polyester film having a sulfonic acid group-containing copolymerized polyester laminated on at least one side of the laminated polyester film, and the copolymerized polyester film is used as an anchor coat of polyaniline. When polyester is used, the adhesion of the polyaniline to the base material is improved.

The laminated polyester film of the present invention, when used for a magnetic recording medium, has good quality due to its antistatic property and adhesive property improving effect.

In the laminated polyester film of the present invention, the surface resistance value of the laminated polyester film on which the polyaniline containing a sulfonic acid group is laminated is 2
In the case of a laminated polyester having a resistance of 10 ⁷ to 10 ¹¹ Ω / □ at 3 ° C. and a relative humidity of 15%, it is possible to provide the most economical polyester film that overcomes the electrostatic damage.

The polyester film as referred to in the present invention means that 90% by mole or more, preferably 95% by mole or more of its repeating unit is ethylene terephthalate or ethylene-2,6.
-Naphthalate, and may contain a known copolymerization component as another component. Further, in order to form fine projections on the film surface, known inert fine particles such as silica, calcium carbonate, kaolin and alumina may be contained as a lubricant.

The sulfonic acid group-containing polyaniline used in the present invention is represented by the general formula (Formula 1).

[0010]

[Chemical 1]

(In the formula (1), R 1, R 2 and R 3 are hydrogen atoms or alkyl groups having 1 to 4 carbon atoms, and x is 50 to 2
000, preferably an integer of 100 to 1500 is shown. ) The compound represented by the general formula (Formula 1) used in the present invention is described in J. Am. Chem. Soc. , 1991, 11
It can be manufactured according to the method described in 3,2665-2666. The compound applicable to the present invention is one in which the sulfonic acid group is introduced into the aromatic ring at a ratio of 1/10 to 4/5, preferably 2/5 to 3/5. Since these are dispersed or dissolved in water, the coating method is the most preferable lamination method, but the method is not limited to this.

The sulfonic acid group-containing copolymerized polyester referred to in the present invention is a dicarboxylic acid component containing a sulfonic acid group-containing monomer as one component, and the ratio of the sulfonic acid group-containing monomer to the total acid component is 1. ~ 50 mol%
Is a copolyester. As the sulfonic acid group-containing dicarboxylic acid, 5-sodium sulfoisophthalic acid is preferable. Other copolymerizable components include carboxylic acid-based terephthalic acid, isophthalic acid, p-β-oxyethoxybenzoic acid, 2,6-naphthalenedicarboxylic acid, 4,
4′-dicarboxyl diphenyl, 4,4′-dicarboxyl benzophenone, bis (4-carboxylphenyl) ethane, adipic acid, sebacic acid, cyclohexane-1,4-dicarboxylic acid and the like can be mentioned. On the other hand, as the glycol-based component, in addition to ethylene glycol, propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanedimethanol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. may be mentioned. To be In addition, a small amount of a compound containing an amide bond, a urethane bond, an ether bond, a carbonate bond or the like may be contained as a copolymerization component.

Further, the magnetic recording medium in the present invention means a magnetic recording medium such as a magnetic tape such as a video tape, an audio tape, a digital video tape, a digital audio tape, a floppy disk, a magnetic card or the like and a polyester film. Is. The surface resistance of the surface of the film of the present invention on which the polyaniline containing sulfonic acid groups is laminated is 10 7 in an environment of 23 ° C. and 15% relative humidity.
It must be -10 11 Ω / □. This range is the most advantageous in terms of productivity and basic unit without electrostatic damage, and the polyester film can be supplied economically.

[0014]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Also, in the example sentences, "parts" means "parts by weight". The evaluation method used in the present invention is also shown below. (1) Surface resistance Takeda Riken Co., Ltd. specific resistance measuring device applied voltage 500V, 2
It was measured under the conditions of 3 ° C. and 15% RH.

(2) Average Particle Size of Lubricant Centrifugal sedimentation type particle size distribution analyzer (SA-CP, manufactured by Shimadzu Corporation)
The value at the cumulative 50% point in the equivalent spherical diameter distribution obtained in 3) was used.

(3) Surface smoothness The film surface of the upper layer was measured with a stylus type three-dimensional surface roughness meter (SE-3AK) manufactured by Kosaka Laboratory under the conditions of a needle radius of 2 μm and a load of 30 mg. With a cut-off value of 0.25 mm and a measurement length of 1 mm, 2 μm
Quantization width is 0.00312 μm for every height direction data
To load it into an external storage device. Such a measurement is continuously performed at 2 μm intervals in the lateral direction of the film as well.
The measurement was performed over a width of 0.3 mm in the lateral direction of the film. The data in the height direction at this time is h (i,
j) [i = 1 to 500, j = 1 to 150],
The value obtained by carrying out the calculation by the following formula was expressed in μm unit, and was designated as TAR [Three Dimensional Average Roughness].

[0017]

[Equation 1]

(4) Sliding property The upper layers of the two films are superposed on each other, and ASTM-D18 is used.
According to 94-63T, the temperature was 23 ° C., the relative humidity was 65%, the tensile speed was 200 m / min, and the dynamic friction coefficient (μ
Displayed in d).

(5) Coarse protrusion number Aluminum was vapor-deposited on the film surface of the upper layer, and a visual field of 5 mm ² or more was observed using a two-beam interference microscope (light source is monochromatic light having a wavelength of 546 nm). The number of secondary and higher order interference rings was counted and converted into the number per 1 mm ² for display.

(6) Adhesiveness evaluation coating Co-γ-Fe ₂ O ₃ 100 parts Vinyl chloride / vinyl acetate copolymer 15 parts Urethane-modified saturated polyester resin 15 parts α-alumina (average particle size 0.5 μm) 3 Parts carbon black (average particle size 0.08 μm) 2 parts toluene 105 parts methyl ethyl ketone 105 parts cyclohexanone 105 parts After mixing and dispersing with the above raw materials for 12 hours with a ball mill, palmitic acid 1 part dodecyl stearate 2 parts oleic acid 2 parts Was added and mixed for another 30 minutes. Next, 10 parts of a 75% solid content ethyl acetate solution of a triisocyanate compound was added and further mixed for 1 hour to obtain a coating material for evaluation. Evaluation of adhesiveness The coating material for evaluation has a thickness of 3 μm after drying on the test film.
Coating, magnetic field orientation treatment, drying at 60 ° C, calendering at 100 ° C, curing at 60 ° C for 72 hours, and then 23 ° C on the coated surface of the obtained film. Scotch tape ("No. 610" manufactured by 3M Co., Ltd.) (width 10 mm x length 1 in an atmosphere of x 50% RH)
(0 cm) was attached so as not to contain air bubbles, and the roll was pressed against it. Then, using Tensilon manufactured by Toyo Baldwin Co., Ltd., peeling was performed at 360 ° at a pulling rate of 1000 cm / min. The distance between chucks was 18 cm, and the adhesive portion was 5 cm.

(7) Blocking resistance [0021] The coated surfaces of two films (3 cm x 3 cm) coated with sulfonic acid group-containing polyaniline were laid one on top of another, and a 6 cm x 6 cm silicone rubber and the same size with a thickness of 7 mm were used. It is sandwiched from both sides by the glass plate of. 2k for this
After applying a load of g and leaving it in an atmosphere of 50 ° C. × 85% RH for 48 hours, the adhesive state when the film was peeled off was observed. ◯: Adhesion is not observed at all Δ: Adhesion of film occurs in places ×: Adhesion occurs on the entire surface

Example 1 (A) Preparation of base film: Polyethylene terephthalate in which fine particles of calcium carbonate having an average particle size of 0.5 μm were dispersed at a concentration of 4000 ppm was melt extruded at 290 ° C. and cooled by a cooling roll at 30 ° C. And the thickness is about 180 μm
Of unstretched film was obtained. This unstretched film is
The base film was stretched 3.5 times in the machine direction between a pair of rolls heated to ℃ and having different peripheral speeds. (B) Preparation of Sulphonic Acid Group-Containing Polyaniline Coating Solution: While stirring 10 g of polyaniline (x = 400) in which sulfonic acid groups were introduced in a ratio of 1/2 to the aromatic ring in 1 l of 0.1 M trimethylamine aqueous solution. Dissolved. 1 l of isopropanol was added to this aqueous solution while continuing stirring to prepare a coating solution.

(C) Preparation of laminated polyester film:
After passing the sulfonic acid group-containing polyaniline aqueous solution obtained in (B) above through a filter having a pore size of 1.0 μm,
It was applied to the surface of the base material film obtained in 1. by a bar coater method, and dried at 70 ° C. with hot air. Then with a tenter 1
200-210 after stretching 3.5 times in the transverse direction at 30 ° C
The film was heat set at 0 ° C. to obtain a biaxially stretched laminated polyester film having a thickness of 14.5 μm. The final coating amount (sulfonic acid group-containing polyaniline) of the film was about 0.04 g / m ² . The physical properties of the obtained film are shown in Table 1.

Example 2 Preparation of (A) Sulfonic Acid Group-Containing Polyester and Aqueous Dispersion: First, a sulfonic acid group-containing polyester was prepared by the following method. Dimethyl terephthalate 49 mol%, dimethyl isophthalate 49 mol% and sodium 5-sulfoisophthalate 2 mol% were used as the dicarboxylic acid component, and ethylene glycol 50 was used as the glycol component.
A transesterification reaction and a polycondensation reaction were carried out by a conventional method using mol% and neobenthyl glycol 50 mol%. The glass transition temperature of the obtained sulfonic acid group-containing polyester was 69 ° C. 300 parts of this sulfonic acid group-containing polyester and 150 parts of n-butyl cellosolve are heated and stirred to form a viscous solution, and while stirring, water 5
50 parts was gradually added to obtain a uniform pale white aqueous dispersion having a solid content of 30%. This dispersion was further added to an equal volume mixture of water and isopropanol to prepare a sulfonic acid group-containing polyester aqueous dispersion having a solid content of 5%.

(B) Preparation of mixed coating solution The coating solution of Example 1 (B) and the aqueous dispersion of Example 2 (A) were mixed at a ratio of 5: 1 (polyaniline and polyester were in a weight ratio of 1: 1). ) To prepare a coating liquid of Example 2. (C) Preparation of Film A base film was prepared in the same manner as in Example 1 except that the coating liquid was changed, and then a laminated film was prepared. The final coating weight of the chopped film was about 0.05 g / m ² . The physical properties of the obtained film are shown in Table 1.

Comparative Example 1 A film which was not coated with the coating solution in Example 1 was used as Comparative Example 1. The physical properties of the obtained film are shown in Table 1.

As shown in Table 1, the laminated polyester film of the present invention has a small surface resistance value even under low humidity while maintaining the original physical properties, and is excellent in antistatic property and adhesiveness.

[0028]

The laminated polyester film of the present invention is
Since it has excellent antistatic properties at low humidity, it can be widely and suitably used as a base material for magnetic recording media, as well as general industrial films and various packaging films.

[0029]

[Table 1]

Claims (5)

[Claims] 1. A laminated polyester film in which a layer containing a polyaniline containing a sulfonic acid group is laminated on at least one surface of the polyester film. 2. A laminated polyester film, wherein the layer containing aniline containing a sulfonic acid group according to claim 1 is a mixture with an anion group-containing aqueous resin. 3. A laminated polyester film according to claim 1, wherein at least one layer of an aqueous resin containing an anion group is laminated on at least one surface of the laminated polyester film. 4. A laminated polyester film according to claim 1, which is for a magnetic recording medium. 5. The surface resistance of the laminated polyester film according to any one of claims 1 to 3 on which the polyaniline having a sulfonic acid group is laminated is 10 ⁷ to 10 ¹¹ Ω / at 23 ° C. and 15% relative humidity. A laminated polyester film characterized by being □.