JP2551646B2 - Thermoplastic resin composition - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition, and more specifically, the film has excellent transparency and slipperiness, and further, the films are rubbed with each other. Even if it relates to a thermoplastic resin composition that is not easily scratched.

[Technical background of the invention and its problems] The properties required of a thermoplastic resin film include slip properties, transparency, low temperature heat sealability, and scratch resistance when the film surfaces are rubbed together. It is known that a thermoplastic resin film has improved slipperiness, that is, a thermoplastic resin to which an inorganic filler such as siloid (silica powder) is added, or a fatty acid amide such as oleic acid amide is added. . However, if an inorganic filler or fatty acid amide is added until sufficient slipperiness is obtained, a decrease in transparency cannot be avoided. When an inorganic filler is added,
It has a fatal defect that the slip property is rapidly lowered at a high temperature of about 80 ° C or higher.

As a method for imparting a low temperature heat-sealing property to a thermoplastic resin film, a method in which a low melting point substance is dissolved in an organic solvent and coated on a stretched substrate film is known. However, although the film produced by the coating method has low-temperature heat-sealing property, the sealing strength is weak,
There is a drawback that the solvent used for coating remains in the film. Further, since a coating process is required in addition to the process for producing the stretched film, the production cost is high.

In order to improve the cost of such a coating method, in producing a biaxially oriented polypropylene film,
A method has been developed in which a resin capable of imparting low temperature heat sealability, such as a propylene-ethylene random copolymer resin or a propylene-ethylene-butene-1 random copolymer resin, is laminated on a film. Furthermore, a method has also been developed in which a second component such as polybutene-1 is added to the resin component used for the above-mentioned lamination to significantly improve the low temperature heat-sealing property (see JP-A-62-233248).

As described above, conventional thermoplastic resin films have improved slipperiness, transparency, or low-temperature heat-sealing property, but none of them have improved. Further, in the conventional film, the problem that scratches are likely to occur when the film surfaces are rubbed with each other has not been solved by various powders added to prevent slippage and blocking phenomenon.

The inventors of the present application have previously proposed a film-forming raw material to which polymethylsilsesquioxane powder is added (Japanese Patent Laid-Open No. 62-215646). This film has a significantly improved slip property and is less likely to be scratched. However, a film that is more slippery and less likely to be scratched by contact with the film is desired.

[Object of the Invention] The present invention solves the above problems and, in addition to transparency, slipperiness and low temperature heat sealability, scratches are less likely to occur when the film surfaces are rubbed (hereinafter, this property It is an object of the present invention to provide a thermoplastic resin composition capable of obtaining a film having "rubbing property").

[Structure of the Invention] The thermoplastic resin composition of the present invention comprises (A) a thermoplastic resin and (B) a general formula; (R ₃ Si) _a Z (wherein R is an unsubstituted monovalent hydrocarbon group and / Or a polyfluoroalkyl group, a represents 1 or 2, Z is a hydrogen atom, a halogen atom, a hydroxyl group, -OR ', -NR'X, -ON when a is 1.
It represents R _'2 or -OOCR', when a is 2 -O -, -
Represents N (X) '-or -S-. However, here R '
Represents an alkyl group having 1 to 4 carbon atoms, and X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms), and polymethylsilsesquioxane powder surface-treated with an organosilicon compound represented by It is characterized by containing.

As the thermoplastic resin as the component (A) used in the present invention,
Polypropylene, polyethylene, 4-methylpentene-
Polyolefins such as 1-polymers and copolymers thereof; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyhexene terephthalate and copolymers thereof; nylon 6, nylon
66, nylon 11, nylon 12, nylon 610, polymeta-xylylene adipamide, polyamide such as polyhexamethylene terephthalic acid amide / isophthalic acid amide and copolymers thereof; and the like. It can be used as one kind or as a mixture of two or more kinds.

As the thermoplastic resin as the component (A), a polyolefin polymer is preferable. Polyolefin-based polymers are thermally stable, do not gel, pyrolyze, or hydrolyze, and do not contain impurities such as oligomers. Therefore, it has various excellent features such as low cost.

Among the polyolefins, polypropylene and its copolymer are particularly preferable. This is because the film is easily formed and the toughness, transparency and heat resistance of the film are excellent.

The polypropylene preferably has an isotactic index II (measured by boiling n-heptane extraction method).
90% or higher, more preferably 95% or higher, and the intrinsic viscosity [η] (135 ° C, measured with a tetralin solution)
Those in the range of 1.2 to 2.5 dl / g are preferable.

When a polypropylene copolymer is used, a random or block copolymer of propylene and ethylene, butene or pentene can be used. This copolymer preferably contains 90% or more of propylene units.

The polymethylsilsesquioxane powder surface-treated with the organic compound as the component (B) used in the present invention is a characteristic that imparts excellent slipperiness and abrasion resistance to the film obtained from the composition of the present invention. It is an ingredient.

The organic compound used for the surface treatment of the polymethylsilsesquioxane powder has a general formula: (R ₃ Si) _a Z (wherein R represents an unsubstituted monovalent hydrocarbon group and / or a polyfluoroalkyl group, a represents 1 or 2,
Z is a hydrogen atom, a halogen atom, a hydroxyl group, when a is 1;
Represents OR ', -NR'X, -ONR' ₂ or -OOCR ', and
When is 2, it represents -O-, -N (X) '-or -S-. Here, R'represents an alkyl group having 1 to 4 carbon atoms, and X represents a hydrogen atom or an alkyl group similar to R '). In the above general formula, the unsubstituted monovalent hydrocarbon group represented by R is a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group or a dodecyl group. Alkyl groups such as; cyclopentyl groups, cycloalkyl groups such as cyclohexyl groups; 2-phenylethyl groups, 2
Examples thereof include an aralkyl group such as a phenylpropyl group; an aryl group such as a phenyl group and a tolyl group; an alkenyl group such as a vinyl group and an allyl group; and the like. An alkyl group of 4 is preferred.

Further, the polyfluoroalkyl group is a monovalent hydrocarbon group which is unsubstituted and at least part of which has hydrogen atoms replaced with fluorine atoms. As such a polyfluoroalkyl group, the easiness of synthesis of the organosilicon compound represented by the general formula and the effect of imparting water repellency are excellent, and therefore, the formula, R ⁴ Q- (in the formula, R ⁴ represents a perfluoroalkyl group having 1 to 20 carbon atoms, and Q represents a divalent unsubstituted alkylene group having 2 to 6 carbon atoms).

Organosilicon compounds include trimethylsilane, triethylsilane, trimethylchlorosilane, trimethylsilanol, trimethylmethoxysilane, trimethylethoxysilane, hexamethyldisilazane, (CH ₃ ) ₃ SiNH
_{CH 3, (CH 3) 3} SiN (CH 3) 2, (CH 3) 3 SiN (C 2 H 5) 2, (CH 3) 3 SiON (C 2 H 5) 2, And the like, but hexamethyldisilazane or a disilazane containing a polyfluoroalkyl group is preferable because unreacted substances can be easily removed after the surface treatment.

Polymethylsilsesquioxane powder is a known compound obtained by hydrolyzing a trifunctional silane such as methyltrichlorosilane.

The polymethylsilsesquioxane powder is, for example, sufficient to neutralize methyltrialkoxysilane and / or its partially hydrolyzed condensate with chlorine atoms present in said silane and / or its partially hydrolyzed condensate. In the method described in JP-A-60-13813 or in JP-A-60-13813, a method of hydrolyzing and condensing in an aqueous solution of ammonia or amine in which an amount of a catalyst is added to the above amount is used. A method of thermally decomposing the obtained polymethylsilsesquioxane powder at a temperature of 500 to 1300 ° C. (JP-A-63-103)
No. 812).

As the polymethylsilsesquioxane powder, it is preferable that the shape thereof is independent and substantially spherical, and 80% or more in the particle size distribution is within the range of ± 30% of the average particle diameter. The average particle size is preferably 0.01 to 20 μm.

The surface treatment method of the polymethylsilsesquioxane powder with the organosilicon compound is particularly limited as long as it is a method capable of keeping the surface of the polymethylsilsesquioxane powder covered with the organosilicon compound. Not a thing. For example, a method of mixing and contacting the organosilicon compound while keeping the polymethylsilsesquioxane powder in a fluid state (Japanese Patent Publication No. 56-41263) or stirring the polymethylsilsesquioxane powder with the organosilicon compound. However, a method of mixing and contacting at a temperature from room temperature to 300 ° C can be applied.

The amount of the organosilicon compound used for the surface treatment can be appropriately selected according to the type, treatment time, treatment temperature and the like.

After such surface treatment, it is preferable to further heat-treat the object to be treated at a temperature of 50 ° C. or higher to remove unnecessary substances.

The blending amounts of the thermoplastic resin as the component (A) and the surface-treated polymethylsilsesquioxane powder as the component (B) are not particularly limited, but when a thermoplastic resin film is to be obtained, it is generally used. The component (B) is preferably 0.01 to 10 parts by weight, more preferably 0.01 to 5 parts by weight, relative to 100 parts by weight of the component (A).

Depending on the type of thermoplastic resin film,
The blending amounts of the component (A) and the component (B) are different.

In the case of an unstretched film, the blending amount of the component (B) is preferably 0.3 to 3 parts by weight, more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the component (A) from the viewpoint of imparting slipperiness and transparency.

In the case of a stretched film, the component (B) projects onto the surface of the film during stretching, so even if it is contained in a smaller amount than in the case of an unstretched film, sufficient slipperiness can be imparted. Therefore, even in a stretched film, the blending amount of the component (B) varies depending on the stretching means.

In the case of a uniaxially stretched film, the content of the component (B) is preferably 0.03 to 1.5 parts by weight, more preferably 0.08 to 1.0 part by weight.

In the case of a biaxially stretched film, the blending amount of the component (B) is preferably 0.01 to 1.0 part by weight, more preferably 0.05 to 0.5 part by weight.

In the case of making a multilayer biaxially stretched film, when the melting point of the layer to which the component (B) is added is lower than that of the other layers,
Component (B) is mixed in a slightly larger amount. This is because, for example, in the case of a film composed of two layers of homopolypropylene and polypropylene copolymer, when the component (B) is used as the slipperiness improving agent for the copolymer layer, the polypropylene copolymer layer is melted or semi-blended in the stretching step. Because it will be in a molten state,
This is because the component (B) does not easily project onto the film surface.
Therefore, in such a case, the blending amount of the component (B) is
0.1 to 2.5 parts by weight is preferable, and 0.3 to 2.0 parts by weight is more preferable.

The composition of the present invention is mainly composed of the components (A) and (B), and other known additives may be added thereto within a range not impairing the object of the present invention.

The method for producing a film using the composition of the present invention is shown below.

For unstretched films, first add the composition to 180-300 ° C.
Then, it is discharged from a slit-shaped die, cast on a cooling drum having a surface temperature of 20 to 90 ° C., and solidified by cooling.

In the case of a stretched film, for example, a biaxially stretched film, the film that is cast and cooled and solidified is heated to 80 to 150 ° C., and then stretched 3 to 7 times in the longitudinal direction. Next, it is stretched 4 to 12 times in the width direction at a temperature of 80 ° C. to a melting point of the thermoplastic resin or less by a tenter type stretching device. After stretching, if necessary, relax the stretched film in the width direction by 0 to 10% at a temperature of 120 ° C or lower than the melting point of the thermoplastic resin for 3 to 1%.
It is also possible to perform heat treatment for 0 seconds.

In the case of a laminated film, a coextrusion method or a method of uniaxially stretching or biaxially stretching and then extruding and laminating a thermoplastic resin can be applied.

In the case of a laminated film, it may be a laminated film of a desired combination of the film of the composition of the present invention and the film of another polymer. By using a laminated film having such a constitution, transparency can be improved without impairing film strength and slipperiness even when the thickness of the film of the composition of the present invention is reduced.

The thickness of the film obtained from the composition of the present invention is 3 to.
100 μm is preferable, and 5-60 μm is more preferable. In the case of a laminated film, the thickness of the film of the composition of the present invention is preferably 0.5 to 8 μm, more preferably 1 to 5 μm.

The obtained film can be subjected to corona discharge treatment or plasma treatment in the atmosphere of carbon dioxide gas, nitrogen gas or the like to improve the surface adhesiveness, and then metal deposition, printing or the like can be performed.

[Effects of the Invention] The film obtained from the composition of the present invention has excellent transparency and slipperiness, and also has excellent rubbing resistance.

Example 1 A flask was charged with 1,000 parts of hexamethyldisilazane and 1,000 parts of polymethylsilsesquioxane powder having an average particle diameter of 2 μm obtained by the method described in JP-A-60-13813. Then, the mixture was stirred at 25 ° C and kept for 15 hours. Then, after suctioning this surface-treated powder with paper,
It was dried in a dryer at ℃ to obtain a surface-treated polymethylsilsesquioxane powder.

Next, surface-treated polymethylsilsesquioxane powder 0.
5 parts and 99.5 parts of polypropylene powder (melting point 162 ° C) are mixed with a Henschel mixer and 250 ° C with a twin-screw extruder.
Was extruded and granulated to obtain chips of the composition of the present invention.

In addition, surface-treated polymethylsilsesquioxane powder 1
And 99.5 parts of powder of ethylene-propylene random copolymer (ethylene unit content 5% by weight, melting point 136 ° C.) were granulated in the same manner to obtain chips of the composition of the present invention.

Two chips of the composition of the invention are used in a two-layer die
Co-extruded at 250 ℃, kept at 40 ℃ to cool and solidify,
A film consisting of two layers was obtained. Then this film 14
It was heated to 0 ° C., stretched 5 times in the longitudinal direction, and immediately cooled to 40 ° C. Next, this film was introduced into a tenter held at 160 ° C. and stretched 8 times in the width direction. The thickness of the whole film after the stretching treatment was 20 μm, and among them, the layer thickness of the ethylene-propylene random copolymer was 3 μm.

The finally obtained film was used to measure the transparency, the slip property and the abrasion resistance.

The transparency was measured according to JIS K 6782. As a result, the haze ratio was 1.1%.

The slip property is the coefficient of static friction when the surfaces of the copolymer layers of two films are rubbed and the coefficient of static friction when the surfaces of the copolymer layers of the film and the metal surface are rubbed by Shinto Kagaku Co., Ltd. It was evaluated by measuring with a friction coefficient measuring device (TYPE-HEIDON-10). As a result, the coefficient of static friction was 0.21 in the case of film surfaces and 0.51 in the case of film surface-metal surface.

The rubbing resistance was evaluated by using two films and measuring the haze ratio of the films after repeating the measurement operation of the friction coefficient 50 times. This haze rate is 1.
It was 2%, which was almost the same as the original haze rate.

For low temperature heat sealability, a 5 mm x 200 mm heat silver is used, and a 20 mm wide sample is cut out from a sample sealed under the heat seal conditions of 120 ° C and a heat seal pressure of 1 kgf / cm ² and a heat seal time of 0.5 seconds. It was evaluated by pulling them apart at a pulling speed of 500 mm / min using a testing machine. As a result, the maximum load was as good as 250 g / 2 cm.

Example 2 Two kinds of books were prepared in the same manner as in Example 1 except that a propylene-ethylene-butene-1 copolymer (ethylene unit content 2.0% by weight, melting point 131 ° C.) was used instead of the ethylene-propylene random copolymer. Chips of the composition of the invention were obtained.

Using these two types of chips, as in Example 1,
A film of layers was produced. The total film thickness is 20 μm
Thus, the thickness of the copolymer layer was 3 μm. The table shows the measurement results of the transparency, the coefficient of static friction and the abrasion resistance of the film.

Example 3 Polymethylsilsesquioxane powder having an average particle diameter of 5 μm obtained by the method described in JP-A-60-13813,
The polymethylsilsesquioxane powder having an average particle size of 0.8 μm obtained by the method described in JP-A-63-103812 was surface-treated in the same manner as in Example 1.

Next, a mixture of two types of surface-treated polymethylsilsesquioxane powders (5 μm particles / 0.8 μm particles = 2/1,
(Weight ratio) 0.4 parts and polypropylene powder 99.6 parts, propylene-ethylene-butene-1 copolymer (ethylene unit content 2.0 wt%, butene-1 unit content 12.5 wt%,
A chip of the composition of the present invention was obtained in the same manner as in Example 1 except that a melting point of 131 ° C) was used.

Using this chip, a two-layer film was produced in the same manner as in Example 1. The thickness of the entire film was 20 μm and the thickness of the copolymer layer was 4 μm. The table shows the measurement results of the transparency, the coefficient of static friction and the abrasion resistance of the film.

Comparative Examples 1 and 2 Instead of the surface-treated polymethylsilsesquioxane powder, silica (manufactured by Fuji Devison Co., Ltd., Cyloid 244)
A film was obtained in the same manner as in Example 1 except that was used.
The table shows the measurement results of the transparency, the coefficient of static friction and the abrasion resistance of the film.

Comparative Example 3 A film was obtained in the same manner as in Example 1 except that polymethylsilsesquioxane powder that had not been surface-treated was used. The table shows the measurement results of the transparency, the coefficient of static friction and the abrasion resistance of the film.

Claims (1)

(57) [Claims] 1. A thermoplastic resin and (B) a general formula; (R ₃ Si) _a Z (wherein R represents an unsubstituted monovalent hydrocarbon group and / or a polyfluoroalkyl group, and a Represents 1 or 2,
Z is a hydrogen atom, a halogen atom, a hydroxyl group, when a is 1;
Represents OR ', -NR'X, -ONR' ₂ or -OOCR ', and
When is 2, it represents -O-, -N (X) '-or -S-. However, here, R'represents an alkyl group having 1 to 4 carbon atoms, and X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). A thermoplastic resin composition comprising sesquioxane powder.