JPH08157666A - Polystyrene resin composition and polystyrene oriented film - Google Patents

Abstract

PURPOSE: To obtain a resin composition excellent in melt thermal stability, lubricity, breakdown voltage (AC), etc., and little in the generation of white powder on the continuous production of a film by compounding a styrenic polymer having a specific structure with a specified amount of spherical aluminosilicate. CONSTITUTION: This resin compositing comprises (A) 90-99wt.% (preferably 95-99.99wt.%) of a styrenic polymer having a highly syndiotactic structure and especially preferably having a weight-average mol.wt. of 50000-1500000 and (B) 0.01-10wt.% (preferably 0.01-5wt.%) of spherical aluminosilicate having a pH of 5-11, an average particle diameter of 0.1-3.0μm (preferably 0.3-2.0μm) and containing components having particle diameters of three times the average particle diameter in an amount of <=3wt.% (preferably <=2wt.%) and an Al2 O3 component content of 0.2-50wt.%. A PS stretched film obtained from the composition is useful as a base material for films used for capacitors, ashesive tapes, electric insulating materials, wrapping materials, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polystyrene resin composition and a stretched polystyrene film, and more specifically, a polystyrene resin composition useful as a material for a stretched film, and various film substrates such as capacitor films, The present invention relates to a polystyrene-based stretched film useful as a base material for films for adhesive tapes, films for electrical insulation, films for packaging, and the like.

[0002]

BACKGROUND OF THE INVENTION Styrene-based polymers having a syndiotactic structure (hereinafter referred to as
It may be abbreviated as "SPS". ) Is the mechanical strength,
Since it has excellent heat resistance, appearance, solvent resistance, etc., it is expected to be used for various purposes. In particular, various film, sheet or fiber extrusion techniques, molded products, applications, etc. have been proposed. On the other hand, in general, the physical properties of extruded products change variously depending on the material and the molding method, and the molding conditions depend on the material properties. Extremely important. In particular, in the development of ultra-thin films, since the slip property of the film is one of the most important properties, S
A method of adding various inorganic particles as an anti-blocking agent to a PS film has been proposed. SP like this
Regarding the S film, JP-A-1-182346, JP-A-3-74437, and JP-A-6-5701.
No. 3, JP-A-6-57014, JP-A-6-5
7015, JP 6-57016, JP 6-57017, JP 6-64036,
JP-A-6-64037, JP-A-6-65399, JP-A-6-65400, and JP-A-6-654.
No. 01, No. 6-65402, No. 6-65402
80793, JP-A-6-91748, JP-A-6-91749, JP-A-6-114924, and JP-A-6-114925.
However, when the conventional inorganic particles were arbitrarily added to SPS, there were problems that the melting heat stability was lowered and that white powder was generated during continuous production of the film. Further, it has been difficult to obtain a film excellent in both slipperiness and AC dielectric breakdown characteristics.

[0003]

Means for Solving the Problems The inventors of the present invention have made earnest studies to solve the above problems and to enable the production of a film having good moldability and slipperiness. As a result, it has been found that melt heat deterioration can be suppressed by using inorganic particles having a specific pH value as a lubricant.
It was also found that the use of inorganic particles having a specific chemical composition can reduce white powder generation during continuous film formation. Furthermore, they have found that by adding a specific amount of inorganic particles having a specific particle size, particle size distribution and shape, a thin film having good slip properties while maintaining mechanical properties and electrical properties can be formed. The present invention is based on such knowledge, a resin composition comprising a specific material and a composition ratio is excellent in melting heat stability, a small amount of white powder is generated during continuous film formation, and slipperiness and dielectric breakdown voltage ( It was completed by finding out that a good stretched film can be provided for AC).

That is, according to the present invention, 90 to 99.99% by weight of a styrenic polymer having a high syndiotactic structure, and a spherical aluminosilicate having a pH of 5 to 0.1 are used.
The present invention provides a polystyrene resin composition characterized by comprising 1 to 10% by weight, preferably 0.01 to 5% by weight. In the present invention, the average particle diameter D of the spherical aluminosilicate is 0.1 to 3.0 μm, preferably 0.3 to.
The above polystyrene resin composition is characterized in that the content of the component having a particle diameter of 2.0 μm and 3 times the average particle diameter D is 3% by weight or less, preferably 2% by weight or less. Is. Further, the present invention provides a polystyrene resin composition, wherein the Al ₂ O ₃ component of the spherical aluminosilicate is 0.2 to 50% by weight. The present invention also provides a polystyrene stretched film formed by molding the above polystyrene resin composition. Hereinafter, the present invention will be described in more detail.

First, the material of the polystyrene resin composition of the present invention will be described. The syndiotactic styrene-based polymer in the present invention means that the stereochemical structure is a syndiotactic structure, that is, a phenyl group or a substituted phenyl group, which is a side chain, alternates with respect to the main chain formed from carbon-carbon bonds. The tacticity is determined by the nuclear magnetic resonance method ( ¹³ C-NMR method) using isotope carbon. ¹³ C-N
The tacticity measured by the MR method can be indicated by the abundance ratio of a plurality of continuous constitutional units, for example, diad in the case of 2, triad in the case of 3 and pentad in the case of 5. The styrene-based polymer having a high syndiotactic structure referred to in the invention is usually 75% or more, preferably 85% or more in racemic dyad, or 30% or more in racemic pentad,
Preferably, polystyrene having a syndiotacticity of 50% or more, poly (alkylstyrene), poly (halogenated styrene), poly (alkoxystyrene), poly (
Vinyl benzoate), hydrogenated polymers thereof and mixtures thereof, or copolymers containing these structural units. Here, as poly (alkylstyrene), poly (methylstyrene), poly (ethylstyrene), poly (propylstyrene), poly (butylstyrene), poly (phenylstyrene), poly (vinylnaphthalene), poly ( Vinyl styrene), poly (acenaphthylene), etc.
(Chlorostyrene), poly (bromostyrene), poly (fluorostyrene), etc. Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene). Of these, particularly preferred styrene-based polymers include polystyrene and poly (p
-Methylstyrene), poly (m-methylstyrene), poly (
Examples thereof include p-tertiarybutylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), and copolymers of styrene and p-methylstyrene ( Japanese Patent Laid-Open No. 62-1877
08 publication).

Further, as the comonomer in the styrene-based copolymer, in addition to the above-mentioned styrene-based polymer monomers, olefin monomers such as ethylene, propylene, butene, hexene and octene, diene monomers such as butadiene and isoprene, and cyclic compounds. Examples thereof include diene monomers, polar vinyl monomers such as methyl methacrylate, maleic anhydride and acrylonitrile. The styrene-based polymer is not particularly limited in molecular weight,
The weight average molecular weight is preferably 10,000 or more and 3,000,000 or less, more preferably 50,000 or more and 1,500,000 or less. If the weight average molecular weight is less than 10,000, stretching may not be performed sufficiently. Further, the molecular weight distribution is not limited in width and width, and various kinds can be applied, but the weight average molecular weight (Mw) /
A number average molecular weight (Mn) of 1.5 or more and 8 or less is preferable. The styrene-based polymer having the syndiotactic structure is remarkably excellent in heat resistance as compared with the conventional styrene-based polymer having the atactic structure. The polystyrene-based resin composition of the present invention contains 90 to 60% of the styrene-based polymer having the above-mentioned high syndiotactic structure in the composition.
It contains 99.99% by weight, preferably 95 to 99.99% by weight.

The polystyrene resin composition of the present invention contains spherical aluminosilicate as an antiblocking agent in an amount of 0.01 to 10% by weight, preferably 0.01 to 5% by weight.
contains. If the spherical aluminosilicate is less than 0.01% by weight, the slipperiness of the film is insufficient, and if it exceeds 10% by weight, breakage occurs frequently during stretching of the film, which is not preferable. This aluminosilicate is amorphous and contains alumina silicate, kaolin, and kaolinite as main components, more specifically, inorganic components such as Al ₂ O ₃ and SiO ₂ . Further, the term “spherical shape” includes not only the case of being a true spherical shape but also the case of having a substantially spherical shape. When it is not a spherical aluminosilicate, the slipperiness after processing the resin composition into a film is insufficient,
It is not possible to provide a stretched film having good slidability. The pH of the spherical aluminosilicate is preferably in the range of 5 to 11, and when the pH is lower than 5 or higher than 11, melting heat deterioration occurs, which is not preferable.

In the present invention, the average particle diameter D of the spherical aluminosilicate is preferably 0.1 to 3.0 μm, more preferably 0.3 to 2.0 μm. Average particle size D is 0.1μ
When it is smaller than m, the slipperiness of the film becomes insufficient, and when the average particle size D is larger than 3.0 μm, white powder is generated in the film forming process, which is not preferable. Further, the content of the component having a particle diameter three times the average particle diameter D of the spherical aluminosilicate is preferably 3% by weight or less, more preferably 2% by weight or less. If the amount of the component having a particle size three times the average particle size D exceeds 3% by weight, white powder is generated in the film forming process, which is not preferable. Further, in the present invention, the Al ₂ O ₃ component of the spherical aluminosilicate is 0.2 to 50% by weight. Al ₂ O ₃
If the content exceeds 50% by weight, white powder is generated in the film forming process, which is not preferable.

In addition, the polystyrene resin composition of the present invention has, if necessary, an —NH— group and a pH of 100,000.
Contains organic compounds having a molecular weight of less than 0. As such an organic compound, one having an electron withdrawing group adjacent to an —NH— group is preferable, and as such an electron withdrawing group, a benzene ring, a naphthalene ring, an anthracene ring, a pyridine ring, a triazine ring, an indenyl ring can be mentioned. It preferably contains an aromatic ring or a carbonyl structure such as a ring and derivatives thereof. The organic compound has a thermal decomposition temperature of 26
Those of 0 ° C. or higher are particularly preferable. Specifically, the following compounds, for example, 2,4-bis- (n-octylthio) -6
-(4-Hydroxy-3,5-di-t-butylanilino) -1,3,5-triazine, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-
Hydrocinnamide), N, N'-bis [3- (3,5-
Di-t-butyl-hydroxyphenyl) propionyl]
Hydrazine, 3- (N-salicyloyl) amino-1,
2,4-triazole, decamethylenedicarboxylic acid disalicyloyl hydrazide, isophthalic acid (2-phenoxypropionyl hydrazide), 2,2-oxazamide-bis [ethyl-3- (3,5-di-t-butyl-4] -Hydroxyphenyl) propionate], oxalyl-bis (benzylidene-hydrazide), N-formyl-N'-
Salicyloylhydrazine, 2-mercaptobenzimidazole, N, N'-di-2-naphthyl-p-phenylenediamine, 4,4'-bis (α, α-dimethylbenzyl) diphenylamine, 2-mercaptomethylbenzimidazole, Styrenated diphenylamine, octylated diphenylamine, N-phenyl-1-naphthylamine, poly (2,2,4-trimethyl-1,2-dihydroquinoline), 6-ethoxy-1,2-dihydro-2,
2,4-trimethylquinoline, N, N'-diphenyl-
p-phenylenediamine, N-phenyl-N '-(1,
3-dimethylbutyl) -p-phenylenediamine, N-
Phenyl-N '-(3-methacryloxy-2-hydroxypropyl) -p-phenylenediamine, thiodiphenylamine, p-aminodiphenylamine, N-salicyloyl-N'-aldehyde hydrazine, N-salicyloyl-N'-acetylhydrazine, N, N'-diphenyl-oxamide, N, N'-di (2-hydroxyphenyl) oxamide, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, N-phenyl-N'-
Isopropyl-p-phenylenediamine and the like can be mentioned. The above-mentioned organic compound having a -NH- group and having a molecular weight of less than 10,000 is optionally contained in the polystyrene stretched film of the present invention in an amount of less than 30% by weight.

The polystyrene resin composition of the present invention comprises
Add other lubricants, other thermoplastic resins, antioxidants, inorganic fillers, rubbers, compatibilizers, colorants, cross-linking agents, cross-linking aids, nucleating agents, plasticizers, etc. within a range that does not impair the purpose. You can also Other inorganic fine particles that can be used in combination with the spherical aluminosilicate of the present invention include Group IA, Group IIA, and IVA.
Group, VIA Group, VIIA Group, VIII Group, IB Group, IIB Group, III
Group B, Group IVB element oxides, hydroxides, sulfides, nitrides, halides, carbonates, sulfates, acetates, phosphates,
Examples thereof include phosphites, organic carboxylates, silicates, titanates, borates and hydrous compounds thereof, complex compounds centering on them, and natural mineral particles.

Specifically, lithium fluoride, borax (sodium borate hydrous salt) and other group IA element compounds, magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, titanic acid. Magnesium, magnesium silicate, magnesium silicate hydrous salt (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate , Strontium titanate, barium carbonate, barium phosphate, barium sulfate, barium phosphite, etc.
IIA group element compounds, titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia),
Group IVA element compounds such as zirconium monoxide, group VIA element compounds such as molybdenum dioxide, molybdenum trioxide and molybdenum sulfide, group VIIA element compounds such as manganese chloride and manganese acetate, group VIII element compounds such as cobalt chloride and cobalt acetate , Group IB element compounds such as cuprous iodide, Group IIB element compounds such as zinc oxide and zinc acetate, aluminum oxide
(Alumina), group IIIB element compounds such as aluminum hydroxide, aluminum fluoride, silicon oxide (silica, silica gel), group IVB element compounds such as graphite, carbon, graphite, glass, carnalite, kainite, mica (mica,
Particles of natural minerals such as quinneum and birose ore. The average particle size of the inorganic fine particles other than the aluminosilicate used here is not particularly limited, but is preferably 0.0
1 to 3 μm, the content in the molded product is 0.001 to 3% by weight,
It is preferably 0.005 to 2% by weight. The inorganic fine particles are contained in the final molded article, but the method of containing them is not limited. For example, a method of adding or precipitating in an arbitrary process during polymerization, a method of adding in an arbitrary process of melt extrusion can be mentioned.

In the present invention, there are various kinds of other thermoplastic resins which can be added to the above-mentioned styrene-based polymer. For example, a styrene-based polymer having an atactic structure, a styrene-based polymer having an isotactic structure, Examples thereof include polyphenylene ether. These resins are easily compatible with the styrene-based polymer having the syndiotactic structure described above, are effective in controlling crystallization when creating a preform for stretching, and are improved in the stretchability after that, and the stretching condition A film that is easy to control and has excellent mechanical properties can be obtained. Among these, in the case of containing a styrene-based polymer having an atactic structure and / or an isotactic structure, those containing the same monomer as the styrene-based polymer having a syndiotactic structure are preferable. The content ratio of these compatible resin components is 1 to 70% by weight, especially 2 to 5%.
It may be 0% by weight. When the content of the compatible resin component exceeds 70% by weight, the heat resistance, which is an advantage of the styrene polymer having a syndiotactic structure, may be impaired, which is not preferable.

Other resins which can be added to the above-mentioned styrene polymer used in the present invention and which are incompatible resins include, for example, polyolefins such as polyethylene, polypropylene, polybutene and polypentene, polyethylene terephthalate, Polyester such as polybutylene terephthalate, polyethylene naphthalate, nylon-
Polyamide such as 6 or nylon 6,6, polythioether such as polyphenylene sulfide, polycarbonate, polyarylate, polysulfone, polyetheretherketone, polyethersulfone, polyimide, vinyl halide polymer such as Teflon, polymethylmethacrylate, etc. Examples of the acrylic polymer, polyvinyl alcohol, etc. other than the above compatible resins include cross-linking resins containing the above compatible resins. These resins are
Since it is incompatible with the styrene-based polymer having a syndiotactic structure used in the present invention, when contained in a small amount, it can be dispersed like islands in the styrene-based polymer having a syndiotactic structure, and after stretching. It is effective for giving moderate gloss and improving the surface slipperiness. The content ratio of these incompatible resin components is 2 to 50% by weight for the purpose of gloss, and 0 for the purpose of controlling the surface property.
001-5 weight% is preferable. Further, when the temperature used as a product is high, it is preferable to use an incompatible resin having relatively high heat resistance.

As the antioxidant, a phosphorus-based antioxidant, a phenol-based antioxidant and a sulfur-based antioxidant can be used. By using such an antioxidant,
A polystyrene resin composition having extremely good thermal stability can be obtained. Here, various types of phosphorus-based antioxidants may be used, and they may be monophosphite, diphosphite, or the like. As a monophosphite, tris (2
4-di-t-butylphenyl) phosphite; tris (mono- and di-nonylphenyl) phosphite and the like. The diphosphite has the general formula

[0015]

Embedded image

[In the formula, R ¹ and R ² may be the same or different and each is an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms or 6 to 2 carbon atoms.
The aryl group of 0 is shown. ] A phosphite represented by the following formula is used, and specific examples thereof include distearyl pentaerythritol diphosphite; dioctyl pentaerythritol diphosphite; diphenyl pentaerythritol diphosphite; bis (2,4-di-t-butylphenyl) Pentaerythritol diphosphite; bis (2
6-di-t-butyl-4-methylphenyl) pentaerythritol diphosphite; dicyclohexyl pentaerythritol diphosphite; tris (2,4-di-t
-Butylphenyl) phosphite; tetrakis (2,4
-Di-t-butylphenyl) -4,4'-biphenylene phosphonite and the like. Among these, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite; bis (2,6-di-t-butyl-
4-methylphenyl) pentaerythritol diphosphite; tris (2,4-di-t-butylphenyl) phosphite; tetrakis (2,4-di-t-butylphenyl) -4,4'-biphenylene phosphonite Is preferably used.

Various kinds of phenolic antioxidants can be used, and specifically, dialkylphenol, trialkylphenol, diphenylmonoalkoxyphenol, tetraalkylphenol and the like are used. As dialkylphenol,
2,2'-methylenebis (6-t-butyl-4-methylphenol); 1,1-bis (5-t-butyl-4-hydroxy-2-methylphenyl) butane; 2,2'-methylenebis (4 -Methyl-6-cyclohexylphenol); 4,4'-thiobis (6-t-butyl-3-methylphenol); 2,2-bis (5-t-butyl-4-)
Hydroxy-2-methylphenyl) -4-n-dodecylmercapto-butane and the like can be mentioned. Examples of the trialkylphenol include 2,6-di-t-butyl-4-methylphenol; 2,2'-methylenebis (6-t-butyl-4-ethylphenol); 2,2'-methylenebis [4-methyl- 6- (α-methylcyclohexyl) phenol]; 2,2′-methylenebis (4-methyl-6-
Nonylphenol); 1,1,3-tris- (5-t-
Butyl-4-hydroxy-2-methylphenyl) butane; ethylene glycol-bis [3,3-bis (3-t
-Butyl-4-hydroxyphenyl) butyrate]; 1
-1-bis (3,5-dimethyl-2-hydroxyphenyl) -3- (n-dodecylthio) -butane; 1,3,5
-Tris (3,5-di-t-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene; 2,2-
Bis (3,5-di-t-butyl-4-hydroxybenzyl) malonic acid dioctadecyl ester; n-octadecyl-3- (4-hydroxy-3,5-di-t-butylphenyl) propionate; tetrakis [methylene (3,
5-di-t-butyl-4-hydroxyhydrocinnamate)] methane; 3,9-bis [1,1-dimethyl-2
-(Β- (3-t-Butyl-4-hydroxy-5-methylphenyl) propionyloxy) ethyl-2,4
8,10-Tetraoxaspiro [5,5] undecane;
Tris- (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate and the like can be mentioned. Examples of diphenylmonoalkoxyphenol include 2,6-diphenyl-4-methoxyphenol, and examples of tetraalkylphenol include tris- (4-t-butyl-2,6-di-methyl-3-hydroxybenzyl)-. Isocyanurate and the like can be mentioned.

Further, as the sulfur type antioxidant, thioether type ones are preferable, and specifically, dilauryl-3,
3'-thiodipropionate; dimyristyl-3,3 '
-Thiodipropionate; distearyl-3,3'-thiodipropionate; pentaerythritol-tetrakis- (β-lauryl-thiopropionate); bis [2
-Methyl-4- (3-n-alkylthiopropionyloxy) -5-t-butylphenyl] sulfide; 2-mercaptobayzoimidazole and the like. Among these, especially pentaerythritol-tetrakis- (β-
Lauryl-thiopropionate) is preferred.

The polystyrene resin composition of the present invention made of such a material can be produced by any method, that is, various methods used for conventional thermoplastic resins. For example, (A) A method in which a styrene-based polymer component having a high syndiotactic structure and (B) a spherical aluminosilicate component are mixed and melt-kneaded by an extruder or the like;
A method of adding the component (B) at any stage of the extrusion process of the component (A), a method of adding the component (B) at any stage of the manufacturing process of the component (A), a component (A) and ( A method of melt-kneading the material in which the component B) is mixed with the component (A) is applicable. A molded product obtained by using the polystyrene resin composition of the present invention has excellent effects in any shape, for example, a film, a sheet, a fiber, a yarn, a pipe, a tray, a three-dimensional molded product obtained by injection molding. And so on. In particular, when a stretched film is produced using this polystyrene resin composition, it has excellent melt heat stability, a small amount of white powder is generated during continuous film formation, and good sliding properties and dielectric breakdown voltage (AC). It is possible to provide a stretched film. When a sheet is produced using the polystyrene resin composition of the present invention, ordinary extrusion molding or the like may be used. At this time, the heating and melting temperature is suitably 270 to 350 ° C. In addition, the obtained sheet has a glass transition temperature of
The heat treatment may be performed at a temperature between the melting points. When producing a stretched film using the polystyrene resin composition of the present invention, the method is not particularly limited, after heating and melting these materials, as a preform, heat stretched, and further heat treatment if necessary. It is obtained by doing.

Next, the stretched polystyrene film according to the present invention will be described. The stretched polystyrene film of the present invention is a stretched film obtained by molding the above polystyrene resin composition. The operations from heating and melting to heat setting when the polystyrene-based stretched film of the present invention is manufactured will be specifically described as follows. First, the polystyrene resin composition obtained as described above is used as a molding material, and this is usually extrusion-molded to obtain a preform for stretching (film, sheet or tube). In this molding, it is common to mold the heat-melted molding material into a predetermined shape with an extruder, but do not heat the molding material and mold it in a softened state. Good.
The extruder used here may be either a single-screw extruder or a twin-screw extruder, and may or may not have a vent. It should be noted that if an appropriate filter is used for the extruder, it is possible to remove impurities and foreign substances.
Further, the shape of the filter can be appropriately selected and used such as a flat plate shape or a cylindrical shape. The extrusion conditions are not particularly limited and may be appropriately selected according to various circumstances, but the temperature is preferably 5 to the melting point of the molding material to the decomposition temperature.
Select in the high temperature range of 0 ° C and set the shear stress to 5 × 10 ⁶ dy.
ne / cm ² or less. The die used may be a T-die, an annular die or the like.

After the above extrusion molding, the obtained preform for stretching is cooled and solidified. At this time, various refrigerants such as gas, liquid and metal roll can be used. When a metal roll or the like is used, it is effective to prevent thickness unevenness and waviness according to methods such as an air knife, an air chamber, a touch roll, and electrostatic printing. The temperature for cooling and solidification is usually 0 ° C.
-The temperature is in the range of 30 ° C higher than the glass transition temperature of the preform for stretching, preferably in the range of 70 ° C lower than the glass transition temperature-glass transition temperature. The cooling rate is 20
It is appropriately selected within the range of 0 to 3 ° C / sec. In the case of biaxial stretching, the cooled and solidified preform may be simultaneously stretched in the machine direction and the transverse direction, but may be sequentially stretched in any order.
The stretching may be performed in one stage or in multiple stages.
The draw ratio is 2 times or more, preferably 3 times or more in terms of area ratio. When the stretching ratio is within this range, the crystallinity of the film is 25% or more, and favorable physical properties can be obtained.

As the stretching method, various methods such as a tenter method, a method of stretching between rolls, a method of bubbling utilizing gas pressure, and a method of rolling can be used. These can be appropriately selected or combined. You can apply. The stretching temperature may be generally set between the glass transition temperature and the melting point of the preform. The stretching speed is usually 1 × 10 to 1 × 10 ⁵ % / min, preferably 1
× 10 ³ to 1 × 10 ⁵ % / min. When the stretched film obtained by stretching under the above-mentioned conditions is required to have dimensional stability at high temperature, heat resistance, and strength balance in the plane of the film, it is preferable to further perform heat setting. The heat setting can be carried out by a commonly used method, but the stretched film is subjected to a tensioned state, a relaxed state or a restricted shrinking state, from the glass transition temperature to the melting point of the film, preferably 100 ° C. lower than the melting point. It may be carried out by maintaining the temperature in the temperature range from the temperature to immediately before the melting point for 0.5 to 120 seconds. The heat setting can be performed twice or more by changing the conditions within the above range. Further, this heat fixing may be performed in an atmosphere of an inert gas such as argon gas or nitrogen gas. The polystyrene-based stretched film of the present invention produced as described above has excellent properties in slipperiness and dielectric breakdown voltage (AC).

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Reference Example 1 17 g of copper sulfate pentahydrate (Cu SO ₄ .5H ₂ O) was placed in a glass container having an inner volume of 500 ml replaced with argon.
(71 mmol), 200 ml of toluene and 24 ml (250 mmol) of trimethylaluminum were added, and the mixture was reacted at 40 ° C. for 8 hours. Then, the solid portion was removed to obtain 6.7 g of a contact product. The molecular weight of this product was 610 as measured by the freezing point depression method.

Production Example 1 [Production of styrenic polymer having syndiotactic structure] In a reaction vessel having an internal volume of 2 liters, the contact product obtained in Reference Example 1 was used as an aluminum atom in an amount of 7.5 mmol.
Triisobutylaluminum 7.5 mmol, pentamethylcyclopentadienyl titanium trimethoxide
0.038 mmol and 1 liter of purified styrene were taken and a polymerization reaction was carried out at 90 ° C. for 5 hours. After completion of the reaction, after decomposing the catalyst component with a methanol solution of sodium hydroxide,
The product was washed repeatedly with methanol and dried to give a polymer.
466g was obtained. The weight average molecular weight of the obtained polymer was 1,
When measured by gel permeation chromatography at 130 ° C. using 2,4-trichlorobenzene as a solvent, it was 290000, and the weight average molecular weight / number average molecular weight was 2.72. Further melting point and ¹³ C-NMR
It was confirmed that the obtained polymer was polystyrene having a syndiotactic structure.

Examples 1 to 5 and Comparative Examples 2 to 5 The syndiotactic styrenic polymer obtained in the same manner as in Production Example 1 was used to display inorganic particles of the types and properties shown in Table 1. 300 ℃
After melt-extruding with, pelletized. With this material,
After melt extrusion at a residence time of 30 minutes and an average temperature of 290 ° C,
A raw sheet was prepared by cooling. Here, the melt index of the material pellet and the raw sheet at 300 ° C. under 2.16 kg was measured. Further, the hue of the original sheet was visually observed. This raw sheet was longitudinally stretched at 110 ° C. to 3.0 times and then transversely stretched at 120 ° C. to 3.0 times.
Heat treatment was performed at 0 ° C. During the final winding process of such continuous film formation, a rubber roll was passed through to observe generation of white powder. The coefficient of friction of the obtained stretched film was measured according to ASTM D-1.
The 984 method and the dielectric breakdown voltage were measured according to JIS C-2318 method. The results are shown in Table 2.

Comparative Example 1 The procedure of Example 1 was repeated except that the inorganic particles were not added. The results are shown in Table 2.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

As described above in detail, the polystyrene resin composition of the present invention is excellent in melt heat stability, has a small amount of white powder generated during continuous film formation, and is suitably used as a material for a stretched film. . Further, the polystyrene stretched film of the present invention has excellent properties such as slipperiness and dielectric breakdown voltage (AC), and can be used as a base material for capacitors, adhesive tape films, electrical insulation films, or as a packaging film. It is suitably used as a base material and the like, and its industrial utility value is extremely large.

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[Procedure amendment]

[Submission date] November 7, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The polystyrene resin composition of the present invention contains spherical aluminosilicate as an antiblocking agent in an amount of 0.01 to 10% by weight, preferably 0.01 to 5% by weight.
contains. If the spherical aluminosilicate is less than 0.01% by weight, the slipperiness of the film is insufficient, and if it exceeds 10% by weight, breakage occurs frequently during stretching of the film, which is not preferable. This aluminosilicate is amorphous and contains alumina silicate, kaolin, and kaolinite as main components, more specifically, inorganic components such as Al ₂ O ₃ and SiO ₂ . Further, the term “spherical shape” includes not only the case of being a true spherical shape but also the case of having a substantially spherical shape. In the case of a non-spherical aluminosilicate, the slidability after processing the resin composition into a film is insufficient, and a stretched film having good slidability cannot be provided. The pH of the spherical aluminosilicate is preferably in the range of 5 to 11, and when the pH is lower than 5 or higher than 11, melting heat deterioration occurs, which is not preferable.

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Examples 1 to 5 and Comparative Examples 2 to 5 The syndiotactic styrenic polymer obtained in the same manner as in Production Example 1 was used to display inorganic particles of the types and properties shown in Table 1. 300 ℃
After melt-extruding with, pelletized. With this material,
After melt extrusion at a residence time of 30 minutes and an average temperature of 290 ° C,
A raw sheet was prepared by cooling. Here, the melt index of the material pellet and the raw sheet at 300 ° C. under 2.16 kg was measured. Further, the hue of the original sheet was visually observed. This raw sheet was longitudinally stretched at 110 ° C. to 3.0 times and then transversely stretched at 120 ° C. to 3.0 times.
Heat treatment was performed at 0 ° C. During the final winding process of such continuous film formation, a rubber roll was passed through to observe generation of white powder. The coefficient of friction of the obtained stretched film was measured according to ASTM D-1.
The 984 method and the dielectric breakdown voltage were measured according to JIS C-2330 method. The results are shown in Table 2.

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Claims (4)

[Claims] 1. A styrenic polymer having a highly syndiotactic structure, 90 to 99.99% by weight, and a pH of 5 to 5.
11. A polystyrene resin composition, which comprises 0.01 to 10% by weight of spherical aluminosilicate of 11. 2. The spherical aluminosilicate has an average particle size D of 0.1 to 3.0 μm, and a component having a particle size three times the average particle size D is 3% by weight or less. The polystyrene resin composition according to claim 1. 3. The spherical aluminosilicate of Al ₂ O ₃
The polystyrene resin composition according to claim 1, wherein the content of the component is 0.2 to 50% by weight. 4. A polystyrene stretched film obtained by molding the polystyrene resin composition according to claim 1.