JPH06335993A - Surface coated thermoplastic resin film and production thereof - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin film improved in slip properties without impairing the transparency of a film or film forming properties. CONSTITUTION:A layer of a granular resin with an average particle size of 0.05-1mum composed of a double-layer structure consisting of 20-70wt.% of a core layer of a methyl methacrylate/styrene/butadiene terpolymer and 80-30wt.% of surface layer of polyethylene is formed on at least the single surface of a thermoplastic resin film and heated to 60 deg.C or higher to obtain a surface coated film. By this method, a surface coated thermoplastic resin film wherein the thickness of the coating layer is 0.002-0.2mum, the coefficient of dynamic friction of the coating surface due to an Euler method is 0.5 or less and haze is 0.70% or less is obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin film having excellent slip properties and transparency.

[0002]

2. Description of the Related Art Generally, a biaxially stretched film made of a thermoplastic resin is widely used in various fields depending on its application due to its excellent characteristics. However, depending on the application and conditions, the film manufacturing process and post-processing step It had the drawback of being difficult to handle due to its low slip properties. Conventionally, in order to improve this defect, as a method of reducing the frictional force on the friction surface between the films or the material in contact with the film, inorganic fine particles such as silicon oxide, alumina and calcium carbonate, and easy sliding of polytetrafluoroethylene and the like have been used. The method of incorporating a volatile polymer has been adopted.

However, in the method of incorporating the above-mentioned inorganic fine particles, there is a problem that the transparency of the film is deteriorated due to the agglomeration between the fine particles and the lack of compatibility with the film base material easily causes the loss of the fine particles. Had. On the other hand, in the method of incorporating the slippery polymer, the heat resistance of the polymer is insufficient, or the transparency of the film is reduced due to the low compatibility with the film base material, or when the film is extruded. There was a problem of poor film formation.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to provide a thermoplastic resin film having improved slip properties and a method for producing the same, without impairing the transparency and film-forming property of the film.

[0005]

The present invention solves the above-mentioned problems, and the gist thereof is as follows. (1) On at least one side of a thermoplastic resin film, a terpolymer of methyl methacrylate, styrene, and butadiene as a core layer of 20 to 70% by weight, polyethylene 80 to 30
It has a two-layer structure with weight% as the surface layer, and the average particle size is 0.05-1μ.
A surface-coated film obtained by forming a layer of m granular resin and then heating it to a temperature of 60 ° C. or higher,
A surface-coated thermoplastic resin film having a coating layer thickness of 0.002 to 0.2 μm, a dynamic friction coefficient of the coated surface according to the Euler method of 0.5 or less, and a haze of 7.0% or less. (2) at least one surface of the unstretched or uniaxially stretched thermoplastic resin film, the core layer of 20-70 wt% terpolymer of methyl methacrylate, styrene and butadiene,
A double-layered structure having 80 to 30% by weight of polyethylene as a surface layer, coated with an aqueous dispersion of a granular resin having an average particle diameter of 0.05 to 1 μm, dried at a temperature of 60 ° C. or higher, and then stretched. The method for producing a surface-coated thermoplastic resin film according to (1) above. (3) At least one surface of the biaxially stretched thermoplastic resin film, a two-layer structure having 20 to 70% by weight of a terpolymer of methyl methacrylate, styrene and butadiene as a core layer and 80 to 30% by weight of polyethylene as a surface layer. The structure has an average particle size
Coat an aqueous dispersion of 0.05-1 μm granular resin,
The method for producing a surface-coated thermoplastic resin film according to (1) above, which comprises drying at a temperature of 60 ° C. or higher.

The present invention will be described in detail below. The thermoplastic resin in the present invention is not particularly limited, but is a polyamide resin represented by nylon 6, nylon 66, nylon 610, nylon 12, nylon 11, polymethaxylylene adipamide, etc. and copolymers thereof. , Polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyarylate and the like and polyester resins represented by their copolymers, polycarbonate resins, polyethylene, polypropylene, ethylene-vinyl acetate copolymers, polymethylpentene, polybutene, poly Examples thereof include polyolefin resins represented by isobutylene, polystyrene and the like. Among them, preferred thermoplastic resins are nylon 6, polyethylene terephthalate and polypropylene.

The resin constituting the coating layer is a terpolymer consisting of methyl methacrylate, styrene and butadiene.
It has a two-layer structure in which 20 to 70% by weight is the core layer and 80 to 30% by weight of polyethylene is the surface layer. 20 core layers
If it is less than 80% by weight, the surface roughness after coating becomes small and sufficient slip properties cannot be obtained. If it exceeds 80% by weight, a stable surface coating layer cannot be obtained. The polymer forming the core layer and the surface layer may be a polymer obtained by copolymerizing a small amount of a monomer having a carboxylic acid group or a metal carboxylate base in addition to the above components.

Further, it is necessary that the average particle diameter of the granular resin constituting the coating layer is 0.05 to 1 μm. If the average particle size is smaller than 0.05 μm, sufficient slip properties cannot be obtained, and if it is larger than 1 μm, haze becomes high and the object of the present invention cannot be achieved.

As such a granular resin, a commercially available one can be used, and there is Pateracor A-704 series manufactured by Dainippon Ink and Chemicals, Inc.

The thickness of the coating layer must be 0.002 to 0.2 μm, preferably 0.04 to 0.1 μm. If the thickness of the coating layer is thinner than 0.002 μm, sufficient slip properties cannot be obtained, and if it is thicker than 0.2 μm, haze becomes high and the object of the present invention cannot be achieved.

The coating layer is formed by coating the above-mentioned aqueous dispersion of the granular resin on at least one side of the thermoplastic resin film. The concentration of the granular resin in the coating solution is preferably 0.1 to 10% by weight. Is. If the concentration of the granular resin in the coating liquid is less than 0.1% by weight, the surface tension of the coating liquid will be high and it will not be possible to coat uniformly. If it exceeds 10% by weight, coating streaks will occur and a uniform coating surface will be obtained. You won't get it.

In addition to the above-mentioned granular resin, a surfactant, an antioxidant, an inorganic fine powder and the like may be added to the coating liquid, if necessary.

Next, the manufacturing process of the coated thermoplastic resin film of the present invention will be described below. First, the thermoplastic resin is T
-Film is formed by a usual film forming method such as a die method or an inflation method.

In the present invention, the coating of the granular resin with the aqueous dispersion can be applied to an unstretched film immediately after film formation, a uniaxially stretched film immediately after stretching in the machine direction or a film after biaxial stretching.

Among the above three methods for obtaining the coated film of the present invention, the method of coating on an unstretched film and simultaneously biaxially stretching, and the method of longitudinally uniaxially stretching and laterally stretching are as follows: Compared to the coating method, it is possible to easily reduce the coating amount, and since the coating is applied in the film manufacturing process, the economic effect is large. Among them, the method of coating on an unstretched film and simultaneously biaxially stretching Is the best economical way.

As the coating method, any known coating method can be applied. For example, a gravure roll system, a metering bar system, a reverse roll system, and a spray system are applied individually or in combination.

When the wetting tension of the thermoplastic resin film before coating is smaller than the surface tension of the aqueous dispersion of the granular resin,
By increasing the wetting tension of the thermoplastic resin film by applying a corona treatment to the thermoplastic resin film or adding a surfactant to the coating liquid, the aqueous dispersion of the granular resin is made uniform on the thermoplastic resin film. Can be coated.

After drying the coated film at a temperature of 60 ° C. or more, when it is coated on an unstretched film, it is simultaneously biaxially stretched, and when it is coated on a longitudinal uniaxially stretched film, it is biaxially stretched film by transverse stretching. It is said that It is desirable that the stretching is carried out at a temperature substantially the same as that of a normal thermoplastic resin film and the stretching ratio is 1.2 to 10 times in both the longitudinal and transverse directions. The drying before stretching may be performed in the preheating part of the stretching process. Next, the stretched film is heat treated under normal heat treatment conditions. When coated on a biaxially stretched film, it only needs to be dried at a temperature of 60 ° C or higher.

The thickness of the surface-coated thermoplastic resin film of the present invention is not particularly limited, but is usually 0.1 to 10
It is 00 μm.

The surface-coated thermoplastic resin film of the present invention can also be used as one layer of a laminated film.

[0021]

According to the present invention, a thermoplastic resin film having a good slip property on the coated surface and a good transparency is provided. The reason for this is not clear, but it is estimated as follows. That is, coating the surface of the film with a two-layer structure granular resin, when heated to a temperature of 60 ℃ or more, the polyethylene of the surface layer of the granular resin is melted, leaving the copolymer of the core layer in the form of protrusions, while the base film The film is adhered to form a film, and fine irregularities are formed on the film surface. The cover layer is made of a transparent polymer and has a small thickness, so that the transparency of the base film is not impaired.

[0022]

EXAMPLES Next, the present invention will be described in detail with reference to examples. The method of measuring the characteristic value is as follows. (a) Coefficient of dynamic friction by Euler's method A film with a width of 50 mm is brought into contact with the portion of the cylinder where the wrap angle is 140 degrees, a load of 1 kg is applied to one end, and the other end is applied with a Shimadzu autograph at a speed of 500 mm / min. It was calculated by the following formula from the tension generated when pulled. μ = (1 / θ) ln (T ₁ / T ₀ ) θ: (140/360) × 2π T ₀ : 1kg T ₁ : Generated tension (kg) (b) Friction coefficient according to ASTM method ASTM-D-1894 The coefficient of kinetic friction was measured according to. (c) Transparency Measured according to JIS-K-6714.

Example 1 Nylon 6 (melting point 220 ° C.) was melt extruded from a T-die at 260 ° C. and cooled on a drum at 30 ° C. to obtain an unstretched film having a thickness of 150 μm. Next, 40% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer on this unstretched film, and polyethylene was used.
Two-layer structure with 60% by weight as the surface layer, average particle size 0.2μ
A water dispersion containing 1.0% by weight of granular resin of m was coated with a rotating Meyer bar to a coating weight of 7 g / m ² , dried at 80 ° C, then tripled vertically at 85 ° C and horizontally. Direction was 3.3 times simultaneously biaxially stretched and further heat treated at 210 ° C. to obtain a biaxially stretched film having a nylon 6 layer thickness of 15 μm and a coating layer thickness of 0.007 μm.

Example 2 The coating resin had a two-layer structure in which 50% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer and 50% by weight of polyethylene was used as a surface layer, and the average particle size was
A biaxially stretched film was obtained in the same manner as in Example 1 except that the granular resin was changed to 0.2 μm.

Comparative Example 1 A biaxially stretched film was obtained in the same manner as in Example 1 except that no coating was applied.

Comparative Example 2 The coating resin has a two-layer structure in which 10% by weight of a terpolymer of methyl methacrylate, styrene and butadiene is used as a core layer and 90% by weight of polyethylene is used as a surface layer, and the average particle size is
A biaxially stretched film was obtained in the same manner as in Example 1 except that 0.2 μm granular resin was used.

Comparative Example 3 The coating resin had a two-layer structure in which 90% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer and 10% by weight of polyethylene was used as a surface layer, and the average particle size was
A biaxially stretched film was obtained in the same manner as in Example 1 except that 0.2 μm granular resin was used. However, the obtained film was not practical because the stability of the surface coating layer was poor.

Example 3 Polyethylene terephthalate (melting point 255 ° C.) was melt extruded from a T-die at 280 ° C. and cooled on a drum at 15 ° C. to obtain an unstretched film having a thickness of 120 μm. The unstretched film was then subjected to a corona treatment to bring the surface tension of the film to 48 dynes / cm. To this corona-treated unstretched film, 30% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer, and polyethylene was used.
Two-layer structure with 70% by weight as the surface layer, with an average particle size of 0.2μ
An aqueous dispersion containing 1.0% by weight of granular resin of m was coated with a rotating Meyer bar to a coating weight of 7 g / m ² , dried at 80 ° C, and then vertically coated at 95 ° C.
Double and 3.3 times in the transverse direction at the same time
Heat treatment at ℃, the thickness of the polyethylene terephthalate layer
A biaxially stretched film having a thickness of 12 μm and a coating layer of 0.007 μm was obtained.

Example 4 Polypropylene (melting point: 160 ° C.) was melt extruded from a T-die at 240 ° C., cooled on a drum at 15 ° C. and had a thickness of 120 μm.
An unstretched film of m 3 was obtained. The unstretched film was then subjected to a corona treatment to bring the surface tension of the film to 48 dynes / cm. This corona-treated unstretched film has a two-layer structure with a core layer of 30% by weight of a terpolymer of methyl methacrylate, styrene and butadiene and a surface layer of 70% by weight of polyethylene, and a granular resin with an average particle size of 0.2 μm. Was coated with a water-dispersed solution containing 1.0% by weight by a rotating Meyer bar to a coating weight of 7 g / m ² .
After drying at 80 ℃, at 150 ℃ 3 times in the vertical direction and in the horizontal direction
The film was simultaneously biaxially stretched 3.3 times and further heat-treated at 150 ° C. to obtain a biaxially stretched film having a polypropylene layer thickness of 12 μm and a coating layer thickness of 0.007 μm.

Example 5 Nylon 6 (melting point 220 ° C.) was melt extruded from a T-die at 260 ° C. and cooled on a drum at 30 ° C. to obtain an unstretched film having a thickness of 150 μm. Then, this unstretched film is
Simultaneously biaxially stretched at 85 ℃ 3 times in the longitudinal direction and 3.3 times in the transverse direction,
Further, this was heat-treated at 210 ° C. to obtain a biaxially stretched film. This biaxially stretched film has a two-layer structure in which 40% by weight of a terpolymer of methyl methacrylate, styrene and butadiene is used as a core layer and 60% by weight of polyethylene is used as a surface layer, and a granular resin having an average particle diameter of 0.2 μm is used. The coating weight of the water dispersion containing 1.0% by weight was 0.7 g with a rotating Meyer bar.
After coating such that / m ^2, the device was then dried at 80 ° C., the thickness of the nylon 6 layer were obtained 15 [mu] m, the thickness of the coating layer is a biaxially oriented film is 0.007.

Table 1 shows the characteristic values of the films obtained in the above Examples and Comparative Examples.

[0032]

[Table 1]

[0033]

According to the present invention, a thermoplastic resin film having an improved slip property is provided without impairing the transparency and film forming property of the film. Further, according to the method of the present invention, coating can be applied in the film manufacturing process, and a coated film can be obtained at low cost. In particular, if a method of coating an unstretched film or a longitudinally uniaxially stretched film and then simultaneously biaxially stretching or transversely stretching it is possible to easily reduce the thickness of the coating layer, which is economically advantageous. .

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[Procedure amendment]

[Submission date] March 14, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

Example 1 Nylon 6 (melting point 220 ° C.) was melt extruded from a T-die at 260 ° C. and cooled on a drum at 30 ° C. to obtain an unstretched film having a thickness of 150 μm. Next, 40% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer on this unstretched film, and polyethylene was used.
Two-layer structure with 60% by weight as the surface layer, average particle size 0.2μ
An aqueous dispersion containing 1.0% by weight of m granular resin was coated with a rotating Meyer bar to a coating weight of 7 g / m ² , dried at 80 ° C, and then tripled vertically at 85 ° C.
The film was simultaneously biaxially stretched 3.3 times in the transverse direction and further heat-treated at 210 ° C. to obtain a biaxially stretched film having a nylon 6 layer thickness of 15 μm and a coating layer thickness of 0.007 μm.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

Example 3 Polyethylene terephthalate (melting point 255 ° C.) was melt extruded from a T-die at 280 ° C. and cooled on a drum at 15 ° C. to obtain an unstretched film having a thickness of 120 μm. The unstretched film was then subjected to a corona treatment to bring the surface tension of the film to 48 dynes / cm. To this corona-treated unstretched film, 30% by weight of a terpolymer of methyl methacrylate, styrene and butadiene was used as a core layer, and polyethylene was used.
Two-layer structure with 70% by weight as the surface layer, with an average particle size of 0.2μ
An aqueous dispersion containing 1.0% by weight of granular resin of m was coated with a rotating Meyer bar to a coating weight of 7 g / m ² , dried at 80 ° C, and then tripled vertically at 95 ° C.
Simultaneously biaxially stretches 3.3 times in the transverse direction and heat-treats it at 230 ° C to make the polyethylene terephthalate layer 12 μ
A biaxially stretched film having a thickness of m 2 and a coating layer thickness of 0.007 μm was obtained.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

Example 4 Polypropylene (melting point 160 ° C.) was melt extruded from a T-die at 240 ° C. and cooled on a drum at 15 ° C. to have a thickness of 120 μm.
An unstretched film of m 3 was obtained. The unstretched film was then subjected to a corona treatment to bring the surface tension of the film to 48 dynes / cm. This corona-treated unstretched film has a two-layer structure with a core layer of 30% by weight of a terpolymer of methyl methacrylate, styrene and butadiene and a surface layer of 70% by weight of polyethylene, and a granular resin with an average particle size of 0.2 μm. coat weight is coated so that 7 g / m ² by a rotating Meyer bar an aqueous dispersion containing 1.0% by weight, 80
After drying at ℃, at 150 ℃ 3 times in the vertical direction, in the horizontal direction
The film was simultaneously biaxially stretched 3.3 times and further heat-treated at 150 ° C. to obtain a biaxially stretched film having a polypropylene layer thickness of 12 μm and a coating layer thickness of 0.007 μm.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0030

[Correction method] Change

[Correction content]

Example 5 Nylon 6 (melting point 220 ° C.) was melt extruded at 260 ° C. from a T-die and cooled on a drum at 30 ° C. to obtain an unstretched film having a thickness of 150 μm. Then, this unstretched film is
Simultaneously biaxially stretched at 85 ℃ 3 times in the longitudinal direction and 3.3 times in the transverse direction,
Further, this was heat-treated at 210 ° C. to obtain a biaxially stretched film. This biaxially stretched film has a two-layer structure in which 40% by weight of a terpolymer of methyl methacrylate, styrene and butadiene is used as a core layer and 60% by weight of polyethylene is used as a surface layer, and a granular resin having an average particle diameter of 0.2 μm is used. The coating weight of the aqueous dispersion containing 1.0% by weight was 0.7 with a rotating Meyer bar.
After coating so as to have g / m ² , it was dried at 80 ° C. to obtain a biaxially stretched film having a nylon 6 layer thickness of 15 μm and a coating layer thickness of 0.007 μm.

Claims (3)

[Claims] 1. A two-layer structure having a core layer of 20 to 70% by weight of a terpolymer of methyl methacrylate, styrene and butadiene as a core layer and a surface layer of polyethylene of 80 to 30% by weight on at least one side of a thermoplastic resin film. And the average particle size is
A surface-coated film obtained by forming a granular resin layer having a thickness of 0.05 to 1 μm and then heating it to a temperature of 60 ° C. or higher, wherein the coating layer has a thickness of 0.002 to 0.2 μm and is subjected to the Euler method of the coated surface. A surface-coated thermoplastic resin film having a dynamic friction coefficient of 0.5 or less and a haze of 7.0% or less. 2. An unstretched or uniaxially stretched thermoplastic resin film having a core layer of 20 to 70% by weight of a terpolymer of methylmethacrylate, styrene and butadiene and a surface layer of polyethylene of 80 to 30% by weight on at least one surface thereof. 2. The surface coating heat according to claim 1, wherein the coating solution is a two-layer structure having an average particle diameter of 0.05 to 1 μm, coated with an aqueous dispersion of granular resin, dried at a temperature of 60 ° C. or higher, and then stretched. A method for producing a plastic resin film. 3. A biaxially stretched thermoplastic resin film has a core layer on at least one side of which is 20 to 70% by weight of a terpolymer of methyl methacrylate, styrene and butadiene.
2. A two-layered structure having 80 to 30% by weight of polyethylene as a surface layer, coated with an aqueous dispersion of granular resin having an average particle size of 0.05 to 1 .mu.m, and dried at a temperature of 60.degree. C. or more. For producing a surface-coated thermoplastic resin film.