JPS61181837A - Thermoplastic resin film - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin film of high transparency and good slipperiness, by adding crosslinked polymer particles of a radical-polymerizable monomer, having a specified average particle diameter and a specified particle diameter distribution to a thermoplastic resin. CONSTITUTION:A thermoplastic resin film containing 0.02-10wt%, based on the thermoplastic resin, crosslinked polymer particles of a radical-polymerizable monomer, having an average particle diameter of 0.5-20mu and such a particle diameter distribution that particles of a particle diameter within the average particle diameter + or -20% account for 90% of the entire particles. As the radical- polymerizable monomer, a polyvinyl compound is used in an amount of 2-60wt%, based on the total monomer. Examples of the polyfunctional compounds include divinyl compounds other than a conjugated diene and trimethylolpropane triacrylate. Preferable examples of the polymer compositions of the crosslinked polymer particles include styrene/divinylbenzene copolymer and vinylidene chloride/acrylonitrile/divinylbenzene.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a thermoplastic resin film with improved slip properties. More specifically, the present invention relates to a thermoplastic resin film, particularly a polyester film, which has improved slipperiness by manufacturing the film after adding fine particles to the thermoplastic resin.

Since double-baked thermoplastic resins have excellent physical and chemical properties, their films are widely used for magnetic tapes, optical photography, vapor deposition, packaging, and the like. However, despite their performance, various undesirable troubles may occur during the manufacturing process. This is thought to be due to the poor slipperiness of the film.

When a thermoplastic resin film, particularly a polyester film, is used as a magnetic tape by coating a magnetic layer on its surface, particularly good slipperiness is required. This is because if the slipperiness of the film is poor, dirt and grime may occur on the film surface during film manufacturing, magnetic layer coating, or other film handling.
This is because wrinkles and the like occur, resulting in drop out (voltage drop phenomenon) and problems with the quality of the magnetic tape. Therefore, films for manufacturing magnetic tapes are particularly required to have good slip properties. Furthermore, since it is essential for a magnetic tape as a product to have good running properties, the film used to manufacture the magnetic tape is required to have good slipping properties in order to meet this requirement.

Originally, in order to improve the slipperiness of a film, it was sufficient to add irregularities to the film surface, and for that purpose conventional methods were used.

A method of adding fine particles to a thermoplastic resin as a film raw material, a method of precipitating insoluble fine particles during polymerization, etc. are known. However, problems still remain with these methods, and the slipperiness of the films obtained by these methods is still insufficient.For example, in the method of adding fine particles,
There are problems with the removal of coarse particles, the shape of the fine particles, the affinity between the fine particles and the thermoplastic resin, etc. Furthermore, the method of precipitating fine particles has problems in controlling the particle size of the precipitated fine particles, the shape of the precipitated fine particles, and the affinity between the precipitated fine particles and the thermoplastic resin.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a thermoplastic resin film, especially a polyester film, which is highly transparent and has good slip properties.

Means for Solving the Problems The present invention provides crosslinked polymer particles having an average particle diameter of 0.5 to 20 pm and containing 90% or more of particles having a particle diameter of ±20% of the average particle diameter, by heat treatment. 0 for plastic resin.
It is a thermoplastic resin film containing 0.02 to 10% by weight.

Components of the present invention will be explained in detail below.

(Radical polymerizable monomer) As the radical polymerizable monomer, a polyfunctional vinyl compound is used in an amount of 2 to 60% by weight, preferably 5 to 5% by weight based on the total monomers.
Those containing 0% by weight, more preferably 10 to 40% by weight can be used.

Examples of polyfunctional compounds include divinyl compounds represented by divinylbenzene (excluding conjugated dienes),
Or trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, or polyethylene glycol diacrylate Polyethylene glycol dimethacrylate, 1.3-butylene glycol diacrylate, 1.3-butylene gelicold dimethacrylate, trimethylolpropane triacrylate, trimethylol Examples include polyvalent acrylates and polyvalent methacrylates such as propane trimethacrylate.

Other radically polymerizable monomers include aromatic monovinyl compounds, ester compounds of monohydric alcohols and ethylenically unsaturated carboxylic acids, vinyl cyanide compounds, ethylenically unsaturated carboxylic acids, vinyl halides, such as vinyl chloride. , /X Vinylidene chlorides such as vinylidene chloride, conjugated dienes such as butadiene and isoprene, etc. 14 or 2M or more can also be used.

Styrene is an aromatic monovinyl compound.

There are α-methylstyrene, p-methylstyrene, chlorstyrene, bromustyrene, etc. Among them, styrene, α-methylstyrene, etc.
-methylstyrene and p-methylstyrene are preferred.

Examples of esters of monohydric alcohols and ethylenically unsaturated carboxylic acids include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, with methyl methacrylate being particularly preferred.

Examples of vinyl cyanide compounds include acrylonitrile and methacrylate trile, with acrylonitrile being particularly preferred.

As the free ethylenically unsaturated carboxylic acid, acrylic acid, methacrylic acid, itaconic acid, maleic acid, etc. can be used.

(Crosslinked Polymer Particles) In the present invention, crosslinked polymer particles are obtained by polymerizing radically polymerizable monomers.

Preferred examples of the polymer composition of the crosslinked polymer particles of the present invention include styrene/divinylbenzene copolymer and styrene/acrylonitrile/divinylbenzene copolymer.

Styrene/methyl methacrylate/divinylbenzene copolymer, vinylidene chloride/acrylonitrile/divinylbenzene copolymer, styrene/trimethylolpropane acrylate copolymer, and these copolymers copolymerized with a small amount of unsaturated carboxylic acid. be.

Among these, those copolymerized with acrylonitrile and those copolymerized with a small amount of unsaturated carboxylic acid are particularly preferred because they have good miscibility with polyester.

As the crosslinked polymer particles of the present invention, those obtained by known manufacturing methods can be used. Known manufacturing methods include the following emulsion polymerization method. In order to adjust the particle size of the crosslinked polymer particles within the scope of the present invention, the emulsion polymerization method is carried out in the following manner.

(1) Soap-free polymerization method, that is, a method in which polymerization is performed without using an emulsifier or using a very small amount of an emulsifier.

(2) A seed polymerization method in which polymer particles are added to the polymerization system prior to emulsion polymerization and emulsion polymerization is carried out.

(3) A core-shell polymerization method in which a part of the monomer components is emulsion polymerized and the remaining monomers are polymerized within the polymerization system.

(4) JP-A-54-97582 and JP-A-Sho. 5
4-126288 (the polymerization method by Nigelstadt et al.

(5) Journal of Polymer Science (J,
Polymer Letter Edition (Polym, Sci.).

Letter Ed, ) 21,937 (1983)
etc., i.e., the method (4) above using a swelling aid (1) or (1) polymerization method without the use of a swelling aid.

Among the above methods, methods (3) and (4) are particularly preferred because they can easily obtain particles of uniform particle size.

According to these methods, it has excellent heat resistance, can withstand various processing conditions, and has high affinity with thermoplastic resins.
Spherical fine particles having a substantially uniform particle size and having an arbitrary particle size within the above-mentioned average particle size range can be obtained.

Suspension polymerization is not preferred because the particle size cannot be controlled within a desired range.

The crosslinked polymer particles used in the present invention have an average particle diameter of 0.5 to 207 zm, and ±20% of the average particle diameter.
If the zero particle size is smaller than 0.5 Bm, the effect on slipperiness will be small, while if it is larger than 20 Bm.

The unevenness imparted to the film surface becomes too large, which tends to cause other problems.

The amount of crosslinked polymer particles added is 0.
02 to 10% by weight. Addition amount of crosslinked polymer particles is 0
．． If the amount added is less than 2% by weight, the effect on slipperiness will be insufficient, and if the amount added is more than 10% by weight, not only will the slipperiness not be improved, but conversely, the unevenness of the film surface will become too large, causing other problems. more likely to cause problems.

The spherical fine particles of the crosslinked polymer may be added to the thermoplastic resin before polymerization, during polymerization, or after the polymerization is completed and pelletized. Furthermore, they may be added during melt extrusion into a sheet. good.

(Thermoplastic resin) The thermoplastic resin to which the present invention can be applied may be any resin that can be formed into a film, such as polyester, polyamide, fluororesin, polyvinylidene chloride, polyvinyl chloride, polystyrene, polyethylene, polypropylene, polycarbonate, etc. However, polyester is particularly suitable.

Example The present invention will be explained in detail with reference to Examples below. In addition.

The scope of the present invention is not limited in any way by the following examples.

Example 1 Styrene/acrylonitrile/divinylbenzene copolymer (polymerization ratio 45/ 40/15) was produced as follows by the method of Nigelstad et al. described above. That is, a mixture of 1 part of azobisisobutyronitrile, 2 parts of 1-chlordodecane, 40 parts of water, and 0.3 parts of sodium lauryl sulfate was applied to an ultrasonic oscillator to obtain a fine dispersion. 1 part, 2 parts (as solid content) of a dispersion of polystyrene particles having a particle size of 0.71 parts m produced by a soap-free polymerization method as a seed, and 16.5 parts of water were added and mixed for 12 hours. To this mixed solution were added 700 parts of water, 1 part of sodium lauryl sulfate, 170 parts of styrene, and 30 parts of divinylbenzene, and polymerization was carried out at 80°C for 8 hours.
It was dry. The particles thus obtained are crosslinked polymer particles.

On the other hand, 0.01 part by weight of zinc acetate was added to 100 parts by weight of dimethyl terephthalate and 80 parts by weight of ethylene glycol to perform polycondensation to obtain polyethylene terephthalate.

0.3% by weight of the above crosslinked polymer particles was added to the above polyethylene terephthalate.

It was melt extruded at 270°C and rapidly solidified on a rotating drum maintained at about 30°C to obtain an unstretched film with a thickness of 500 JLm.

This unstretched film was stretched 4 times each in the longitudinal and transverse directions at 90°C and heat treated at 200°C for 15 seconds to obtain a film with a thickness of 60 parts m. About this film
The coefficient of friction was measured by the method of TM 01894-63. Normally, the coefficient of friction is preferably 0.4 or less, but the static friction coefficient of the obtained film was 0.33. The coefficient of dynamic friction was 0630, and it had excellent sliding properties.

11 LA” According to the present invention, the following effects can be obtained.

(1) The crosslinked polymer particles used as a slipperiness improver in the present invention have a spherical shape, no protrusions on the particle surface, and a uniform particle size.

Moreover, since particles of any desired size can be obtained, there is no need to remove coarse particles, and there are no problems in controlling the particle size such as classification.

(2) The crosslinked polymer particles used as a slipperiness improver in the present invention have high affinity with polyester and are well dispersed in polyester.

(3) The crosslinked polymer particles used as a slipperiness improver in the present invention have excellent solvent resistance and heat resistance and can withstand various processing conditions. Especially the highest 2
It is also important to be able to withstand polyester film manufacturing processes that involve operating temperatures of about 80°C.

(4) According to the method of the present invention, a polyester film having good slip properties, high transparency, and excellent performance can be easily obtained.

(5) Since the polyester film obtained by the method of the present invention has high transparency, it is also effective as a film for optical photography.

Claims (1)

[Claims] Crosslinked polymer particles of a radically polymerizable monomer having an average particle diameter of 0.5 to 20 μm and 90% by weight of the entire particles falling within the range of ±20% of the average particle diameter are used for thermoplastic resin, Thermoplastic resin film containing 0.02 to 10% by weight.