JPH03109453A - Slippery film and production thereof - Google Patents

Abstract

PURPOSE:To obtain a slippery film having a rough surface on one side and a flat surface on the other side and exhibiting excellent flatness and slipperiness by laminating a plain resin layer and/or a resin layer containing inorganic particles on one surface of a layer composed of a styrene polymer having syndiotactic structure. CONSTITUTION:The objective film having a rough surface on one a side and flat surface having surface roughness of 0.001-0.02mum on the other side and having a static frictional coefficient of 0.3-1 can be produced by laminating a layer composed of a plain resin and/or a resin containing inorganic particles (especially a syndiotactic styrene polymer containing inorganic fine particles having an average particle diameter of 0.01-3mum) to a surface of a drawn film composed mainly of a styrene polymer having syndiotactic structure (especially a polymer having residual aluminum content of <=3,000ppm, residual titanium content of <=10ppm and residual styrene monomer content of <=7,000ppm) during the production process of the drawn film (especially before or after the drawing process or after the thermal treatment).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a slippery film and a method for producing the same, and more specifically, it is made of a styrene polymer having a syndiotactic structure and has a high degree of smoothness and slipperiness. The present invention relates to a film having the above-mentioned properties and an efficient manufacturing method thereof.

[Prior Art and Problems to be Solved by the Invention] Generally, the thinner the plastic film is, the more processability and slipperiness are required. In particular, industrial films such as magnetic tapes require both slipperiness and smoothness.

Incidentally, in the field of magnetic tapes, films with even better smoothness have been required as the density has increased recently.

Stretched films of styrenic polymers with a syndiotactic structure, which have been developed in recent years, have excellent heat resistance, two-dimensional stability, electrical insulation properties, etc., and are expected to have a variety of uses, and are particularly promising as industrial films.

On the other hand, with the advancement of film-forming technology, polyethylene terephthalate (PET) films have been developed that satisfy high levels of smoothness and slipperiness. Problem: Hydrolysis under high humidity.

There is a problem of dimensional change, and furthermore, when the glass transition temperature is exceeded, elongation occurs, which causes problems when used in high-temperature automobiles.

Styrenic polymers with a syndiotactic structure have properties that can solve the above problems, but a film that satisfies a high level of smoothness and slipperiness has not yet been obtained.

Therefore, the present inventors have conducted extensive research in order to solve the above-mentioned problems and develop a film that has high smoothness and slipperiness while maintaining the properties of the stretched film.

[Means to solve the problem]

As a result, we used a styrene polymer with a syndiotactic structure or its composition as a film material, and one side of the film was rough and the other side was smooth, and the surface roughness and coefficient of static friction were adjusted within a certain range. was found to be suitable for the above purpose. The present invention was completed based on this knowledge.

That is, the present invention provides a stretched film of a styrenic polymer having a syndiotactic structure or a composition thereof, or a laminated film containing the stretched film, wherein one side is a rough surface and the other side is a smooth surface, and the smooth surface The surface roughness Ra of
, ooi to 0.02 μm, and the static friction coefficient μs of the film is 0.3 to 1. The present invention provides an easily slippery film characterized by being O.

The styrenic polymer having a syndiotactic structure used in the present invention means that the stereochemical structure is a syndiotactic structure, that is, a phenyl group or substituted phenyl group that is a side chain with respect to the main chain formed from carbon-carbon bonds. It has a three-dimensional structure in which C-NMs are alternately located in opposite directions, and its toughness can be determined by nuclear magnetic resonance method using carbon isotope ("C-NM").
R method). Toughness measured by the heavy 3C-NMR method is the proportion of a plurality of consecutive structural units, for example, in the case of two units, it is a diad.

In the case of 3 atoms, it can be expressed as triat, and in the case of 5 atoms, it can be expressed as pentad, but the styrenic polymer mainly having a syndiotactic structure as referred to in the present invention is usually racemic diamond with a proportion of 75% or more, preferably 85%. Polystyrene having a syndiotacticity of 30% or more, preferably 50% or more in racemic pentads.

Refers to poly(alkyl styrene), poly(halogenated styrene), poly(alkoxystyrene), poly(vinyl benzoate), hydrogenated polymers thereof, mixtures thereof, or copolymers containing these structural units. do. In addition, poly(alkylstyrene) here is poly(methylstyrene).

Poly(ethylstyrene), poly(propylstyrene).

Poly(butylstyrene), poly(phenylstyrene).

Poly(vinylnaphthalene), poly(vinylstyrene).

Poly(acenaphthylene), etc. Poly(halogenated styrene) includes poly(chlorostyrene).

Examples include poly(bromostyrene) and poly(fluorostyrene). Furthermore, examples of poly(alkoxystyrene) include poly(methoxystyrene) and poly(ethoxystyrene). Among these, a particularly preferred styrenic polymer is polystyrene.

Poly(p-methylstyrene), poly(m-methylstyrene), poly(p-tert-butylstyrene).

Examples include poly(p-chlorostyrene), poly(m-chlorostyrene), poly(p-fluorostyrene), and copolymers of styrene and P-methylstyrene (JP-A-62-187708). ).

Furthermore, as comonomers in the styrene copolymer, in addition to the above-mentioned styrene polymer monomers, olefin monomers such as ethylene, propylene, butene, hexene, and octene, diene monomers such as butadiene and isoprene, cyclic diene monomers, etc. methyl methacrylate,
Examples include polar vinyl monomers such as maleic anhydride and acrylonitrile.

In addition, this styrene polymer has a weight average molecular weight of 10,000 or more and 3,000 or more, although there is no particular restriction on the molecular weight.
0,000 or less is preferred, especially so, oo
The optimum value is 0 or more and 1,500,000 or less.

If the weight average molecular weight is less than 10,000, sufficient stretching cannot be achieved. Furthermore, there are no restrictions on the width or narrowness of the molecular weight distribution (it is possible to apply various values, but the weight average molecular weight (Mw)/number average molecular weight ffi
(Mn) is preferably 1.5 or more and 8 or less. Note that this styrenic polymer having a syndiotactic structure has much better heat resistance than conventional styrenic polymers having an active structure.

Furthermore, among these styrenic polymers, 300℃,
Melt viscosity at shear rate 200/sec is 1 x 102 to lXl
Those with 0' voids are particularly preferred.

A styrenic polymer having such a syndiotactic structure can be prepared by combining (A) a titanium compound and (B) water with an organoaluminum compound, especially a trialkylaluminum, in an inert hydrocarbon solvent or in the absence of a solvent. It can be produced by polymerizing a styrene monomer (monomer corresponding to the above styrene polymer) using the condensation product of as a catalyst (Japanese Unexamined Patent Publication No. 187708/1983).

Furthermore, poly(halogenated alkyl styrene) is disclosed in JP-A-1-146912, and hydrogenated polymers thereof are disclosed in Japanese Patent Application No. 62-335893.

In the present invention, a monolayer film made of the above-mentioned stretched film or a laminated film containing the stretched film is used as the material of the easily slippery film.

In addition, this slippery film must have one side rough and the other side smooth, and the smooth side should have a surface roughness Ra of 0.001 to 0.02 μm.

Preferably it is 0.003 to 0.018 μm. - way,
There is no particular limit to the surface roughness Ra of the rough surface, but it is usually in the range of 0.005 to 0.05 μm, and
The ratio of the surface roughness of the rough surface to the smooth surface (i.e., the surface roughness of the rough surface/
The surface roughness of the smooth surface is 1.5 to 10, preferably 1.
It is desirable to adjust it so that it is 8-8.

In addition, the static friction coefficient μs of this film is 0.3 to 1.0
, preferably 0.3 to 0.8. Note that the static friction coefficient here refers to the friction coefficient between a rough surface and a smooth surface.

As the film material constituting this smooth surface, a styrene polymer having a syndiotactic structure or its composition may be used, but in particular, the residual aluminum content is 300%.
0 ppm or less, the residual titanium content is 10 ppm or less, and the residual styrene monomer is 7000 ppm or less, especially the residual aluminum content is 11000 pp or less, the residual titanium content is 7 ppm or less, and the residual styrene monomer is 5000 ppm or less.
A styrenic polymer having a syndiotactic structure with a high purity of pm or less, or a composition containing this styrenic polymer as a main component and blended with other resins and various additives is preferably used.

To produce such high-purity styrenic polymers,
There are various methods, such as the following. First, in order to suppress the residual aluminum content and the residual titanium content within the above range, there is a method for producing a styrenic polymer using a highly active catalyst (see the specification of Japanese Patent Application No. 7466/1986).
Or ■ method by deashing and washing, that is, JP-A-62-
A styrenic polymer with a syndiotactic structure obtained by polymerizing a styrenic monomer using an ordinary IVA group organometallic compound described in Publication No. 187708 and an alkylaluminoxane such as methylaluminoxane as a catalyst component. This is a method of deashing with a solution of acid or alkali dissolved in an appropriate solvent, and washing with an appropriate solvent.

In this way, a styrenic polymer with a syndiotactic structure with a low residual aluminum content and a low residual titanium content can be obtained by the method (1) or (2). The styrene monomer content is 7000 ppm or less.

(2) Method of drying the styrenic polymer under reduced pressure When drying under reduced pressure, it is efficient to set the drying temperature to the glass transition temperature or higher of the polymer.

(2) Method of degassing the above styrenic polymer using an extruder The above styrenic polymer or the styrenic polymer dried under reduced pressure by the method (2) is degassed using an extruder, and at the same time is used as a molding material (pellet). Here, the extruder is preferably equipped with a vent, and either a -shaft or two-wheel extruder may be used.

Through such treatment, a highly purified styrenic polymer having a syndiotactic structure with a small residual aluminum content, residual titanium content, and residual styrene monomer can be obtained.

In addition, there are various other resins that can be blended with the above-mentioned high-purity styrenic polymer to form a composition.
For example, styrene polymers with atactic structure, styrene polymers with isotactic structure, styrene-maleic anhydride copolymers.

Polyphenylene ether etc. are easily compatible with the above-mentioned styrenic polymer having a syndiotactic structure, and are effective in controlling crystallization when creating a preform for stretching, improving subsequent stretching properties and improving stretching conditions. It is possible to obtain a film that is easy to control and has excellent mechanical properties. this house,
When a styrene polymer having an atactic structure and/or an isotactic structure is contained, it is preferably made of the same monomer as the styrene polymer having a syndiotactic structure. Further, the content ratio of these compatible resin components may be 70 to 1% by weight, particularly preferably 50 to 2% by weight. If the content of the compatible resin component exceeds 70% by weight, it is not preferable because the advantages of the syndiotactic styrene polymer, such as heat resistance, will be impaired. Further, examples of the incompatible resin include polyethylene.

Polyolefins such as polypropylene, polybutene, polypentene, and polyethylene terephthalate.

Polyesters such as polybutylene terephthalate and polyethylene naphthalate, polyamides such as nylon-6 and nylon 6.6, polythioethers such as polyphenylene sulfide, and polycarbonates.

Polyarylate, polysulfone, polyether ether ketone, polyether sulfone, polyimide, halogenated vinyl polymers such as Teflon, acrylic polymers such as polymethyl methacrylate, polyvinyl alcohol, etc., all other than the compatible resins listed above are equivalent. Furthermore, crosslinked resins containing the above-mentioned compatible resins can be mentioned. These resins are incompatible with the styrenic polymer having a syndiotactic structure of the present invention, so if they are contained in small amounts, they cannot be dispersed like islands in the styrenic polymer having a syndiotactic structure. It is effective in imparting a suitable gloss after stretching and improving surface slipperiness. The content ratio of these incompatible resin components is 50 to 2 when the purpose is gloss.
Weight%, if the purpose is to control surface properties, 0.001~
5% by weight is preferred. Furthermore, when the temperature at which the product is used is high, it is preferable to use an incompatible resin that is relatively heat resistant.

Furthermore, there are various additives that can be added to the above-mentioned high-purity styrenic polymer, including antioxidants, antistatic agents, coloring agents, and weathering agents. may be appropriately blended within a range that does not impede the purpose of the present invention.

One method for producing the slippery film of the present invention is to extrude the above-mentioned high-purity styrenic polymer or its composition into a film or sheet while heating and melting it, solidify it by cooling, and then stretch it. In the process of forming a film with a smooth surface by heat treatment (particularly before and after stretching or after heat treatment), a suitable resin and/or
Another method is to laminate layers made of resin containing inorganic particles. Lamination of this resin layer can be done by various methods, but usually a method in which the above-mentioned resin or a resin containing inorganic particles is melted or melted and applied to one side of the above-mentioned smooth film; Alternatively, the above-mentioned high-purity styrene polymer and a resin containing inorganic particles or a suitable resin may be coextruded and co-stretched. The resin used for lamination here may be the styrene polymer of the present invention or the blended resin (other resin) described above, but a resin with a high melting point or softening point is preferable.

An adhesive resin can also be used between those layers.

Also, the type of inorganic particles contained in this resin.

The particle size may be the same as that of the inorganic particles described below.

One suitable method for producing the slippery film of the present invention is a method of laminating the above-mentioned high-purity styrenic polymer and a styrenic polymer containing inorganic fine particles. , the above-mentioned high-purity styrenic polymer is used as component (a), and the styrenic polymer having a syndiotactic structure has an average particle size of 0.01 to 38 m, preferably o.

An example of a manufacturing method is to use a composition comprising inorganic particles of ~lum as component (b), coextrude component (a) and component (I) while heating and melting, and then stretch. After performing this coextrusion, it is usually preferable to perform cooling and solidification, and then to perform a stretching treatment. Further, after this stretching, it is preferable to perform heat treatment (heat setting) as necessary.

The content of inorganic particles in the composition as component (B) is not particularly limited, but is usually 0.001 to 1%.
, preferably in the range of 0.001 to 0.8% by weight.

If the average particle size of the inorganic particles is smaller than 0.01 μm, dispersion will be difficult due to secondary aggregation of the particles, and if the average particle size is larger than 3 μm, smoothness will be lost. Further, if the content of inorganic particles in the composition is less than 0.001% by weight, there is no effect of improving slipperiness, and if the content is more than 1% by weight, it becomes difficult to stretch a thin product.

There are various kinds of the above-mentioned inorganic particles, for example, IA group,
Group IIA, Group IVA, Group VIA, Group ■A, Group ■.

Oxides of group IB, ffB, IIIB, and IVB elements.

hydroxides, sulfides, nitrides, halides, carbonates,
Shows acetates, phosphates, phosphites, organic carboxylates, silicates, titanates, borates and their hydrated compounds, complex compounds centered on them, and natural mineral particles. Specifically, lithium fluoride.

Group IA element compounds such as borax (sodium borate hydrate),
Magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, magnesium silicate, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate ( Group IIAIA element compounds such as gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, strontium titanate, barium carbonate, barium phosphate, barium sulfate, barium phosphite, titanium oxide ( titania), - titanium oxide.

Titanium nitride, zirconium dioxide (zirconia).

- Group IVA element compounds such as zirconium oxide, VI such as molybdenum dioxide, molybdenum dioxide, molybdenum sulfide, etc.
■A of AIA group element compound manganese, manganese acetate, etc.
Group element compounds, Group I 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, and aluminum oxide (alumina).

Group IIIB element compounds such as aluminum hydroxide, aluminum fluoride, aluminosilicate (alumina silicate, kaolin, kaolinite), silicon oxide (silica, silica gel), IVB such as graphite, carbon, graphite, glass, etc.
Carnalite, a group element compound.

Examples include particles of natural minerals such as kainite, mica, and villoseite.

In addition, the composition which is the component (b) mentioned above may not contain particles of other types or particle sizes, inorganic fillers, etc. in addition to the above-mentioned inorganic particles, as long as they do not impede the purpose of the present invention. Good too.

The inorganic particles used above are the final molded product (film)
However, there are no limitations on the method of containing it. Examples include a method of adding or precipitating the styrenic monomer at any step during polymerization, and a method of adding at any step of melt extrusion.

Among these, a method in which the inorganic particles are added in the form of a slurry at any stage of the polymerization process is particularly preferred since secondary aggregation of the particles can be prevented.

Further, in order to effectively disperse these inorganic particles, a dispersant, a surfactant, etc. may be used.

The composition of component (b) is basically a mixture of inorganic particles in a predetermined ratio with the styrene polymer, but other ingredients may be added in consideration of moldability, mechanical properties, surface properties, etc. The resin component may also be included.

As one embodiment of the method for producing the slippery film of the present invention, as described above, the above (a) component and (b) component are coextruded while being heated and melted, and after cooling and solidifying, stretching treatment is performed, and if necessary, A method of heat setting (heat treatment) can be mentioned, and the operations from heating and melting to heat setting are specifically explained as follows.

First, components (a) and (b) as described above are used as a molding material, which is usually coextruded to form a preform for stretching (
original fabric sheet). In this molding, it is common to heat and melt the above-mentioned molding material and mold it into a predetermined shape using an extrusion molding machine, but the molding material is molded in a softened state without being heated and melted. Good too. The extrusion molding machine used here may be either a -shaft extruder or a twin-screw extruder, and may be either with a vent or without a vent, but a -shaft tandem type is preferred. Note that an appropriate mesh may be used for the extruder.

In addition, the extrusion conditions are not particularly limited and may be appropriately selected depending on various situations, but preferably the temperature is selected within the range of 50°C higher than the melting point of the molding material to the decomposition temperature, and the shear stress is 5×10'dyne/cm or less.

The die used may be a T-die, an annular die, or the like.

After the above-mentioned coextrusion molding, the obtained raw sheet is cooled and solidified. As the refrigerant at this time, various types such as gas, liquid, and metal rolls can be used. When using a metal roll or the like, methods such as an air knife, air chamber, touch roll, and electrostatic charging are effective in preventing thickness unevenness and waviness.

The temperature for cooling and solidification is usually in the range of 0° C. to 30° C. higher than the glass transition temperature of the original sheet, preferably in the range of 20° C. lower than the glass transition temperature to the glass transition temperature. Further, the cooling rate is appropriately selected within the range of 200 to 3°C/sec.

In the present invention, a cooled and solidified preform (original sheet)
Stretch to the -axis or two wheels. In the case of biaxial stretching, it may be stretched simultaneously in the longitudinal and transverse directions, or it may be stretched sequentially in any order. Also, stretching may be performed in one step,
It may be done in multiple stages.

The stretching method used here is a method using a tenter.

There are various methods such as stretching between rolls, bubbling using gas pressure, and rolling, and these may be appropriately selected or combined. The stretching temperature may generally be set between the glass transition temperature and melting point of the original sheet.

In addition, the stretching speed is usually 1×10 to 1×10’%/min,
Preferably it is 1X10'' to 1×IO'%/min.

In cases where the stretched film obtained by stretching under the above-mentioned conditions is required to have further dimensional stability at high temperatures, heat resistance, and in-plane strength balance of the film, it is preferable to further heat set the film. Heat setting can be carried out by a commonly used method, and the stretched film is placed under tension, relaxation or limited shrinkage, and the temperature is set between the glass transition temperature and the melting point of the film, preferably 100°C lower than the melting point. This may be carried out by holding the temperature for 0.5 to 120 seconds in the temperature range from the temperature to just below the melting point. Note that this heat fixing can be performed two or more times under different conditions within the above range. In addition, this heat fixation may be performed in an inert gas atmosphere such as argon gas or nitrogen gas. If this heat fixation is not performed, deformation is likely to occur, especially near the glass transition temperature, and there will be restrictions during processing and use. be.

The easily slippery film of the present invention obtained in this way has a thickness of 2 to 500 μm, and has a rough surface on one side and a smooth surface on the other side, and the surface roughness of the smooth surface and the coefficient of static friction of the film are as described above. It will be within the range of .

In particular, films with a thickness of 2 to 20 μm are suitable for magnetic tapes and capacitors, and films with a thickness of 20 to 150 μm are suitable for magnetic cards, printed circuit board substrates, and photographic films.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Reference Example 1 (1) Preparation of contact product between trimethylaluminum and water In a glass container with an internal volume of 500 mil and replaced with argon, copper sulfate pentahydrate (CuS Oa .5 HzO) 1 was placed.
7.8 g (71 mmol), 200 d of toluene and 24 d of trimethylaluminum (250 mmol of C) were added,
The reaction was carried out at 40°C for 8 hours. Thereafter, from the solution obtained by removing the solid portion, toluene was further distilled off under reduced pressure at room temperature to obtain 6.7 g of a contact product.

The molecular weight of this substance measured by freezing point depression method is 61
It was 0. In addition, the aforementioned high magnetic field component (i.e., -0, 1 to -0.5 ppm) by 'H-NMR measurement was 43%.
Met.

(2) Production of styrenic polymer composition containing inorganic particles 99.5 parts by weight of purified styrene monomer was added to dry process silica (Nippon Aerosil, Aerosil TT-972 (-size particle diameter 0.3μ)) ), 0.5 parts by weight of T,
A styrene mixture was prepared by mixing and stirring in a cylindrical container using Homomixer L type (manufactured by Tokushu Kika Kogyo).

At this time, 0.2 parts by weight of calcium stearate was added.

Next, in a reaction vessel with an internal volume of 22, 5 mmol of the contact product obtained in (1) above as aluminum atoms, 5 mmol of triisobutylaluminum, and 0.025 mmol of pentamethylcyclopentagenyl titanium trimethoxide. and the above styrene mixture 12, and heated to 90°C.
The polymerization reaction was carried out for 5 hours. Thereafter, a methanol solution of sodium hydroxide was injected to decompose the catalyst component to stop polymerization, and after repeated washing with methanol, the mixture was dried to obtain 300 g of a polymer.

The weight average molecular weight of this polymer was measured by gel permeation chromatography at 135°C using 1.2.4-trichlorobenzene as a solvent and was 389.
, 000, and the weight average molecular weight/number average molecular weight was 2.64. Furthermore, by melting point and C-NMR measurements, it was confirmed that this polymer was polystyrene with a syndiotactic structure.
00”C.

The melt viscosity at a shear rate of 200/sec was 1X10'voids.

This polymer was dissolved in 1,2,4-trichlorobenzene at 130°C, filtered, and the silica content in the polymer was determined to be 0.5 wt%. Further, this solution was dropped onto a glass slide and observed under a microscope to find out the average particle size of the silica, which was 0.08 μm.

Furthermore, this styrene polymer was heated at 150°C for 2 hours.
Dry under reduced pressure. The obtained powder was extruded at 300°C using a vented twin-screw extruder with a capillary at the tip, cooled, and then cut into pellets. This pellet was crystallized while stirring with hot air. This pellet has 700 pp of styrene monomer with 35% crystallinity.
It contained m.

Reference Example 2 (Production of styrenic polymer containing no inorganic particles) A styrenic polymer was produced in the same manner as in Reference Example 1 (2) above using a styrene monomer containing no dry silica.

The obtained polymer had a weight average molecular weight of 417,000 and a weight average molecular weight/number average molecular weight of 2.54. Affi content was 75 ppm+ T1 content was 2 ppr@. The melt viscosity of this polymer at 300° C. and a shear rate of 200/sec was 1.2×10′ voids. This styrenic polymer was made into pellets in the same manner as in Reference Example 1(2) above. The crystallinity of this pellet was 30%, and the styrene monomer content was 800 pp.

Example 1 The materials obtained in Reference Examples 1 and 2 were heated and crystallized, and then melted and heated to be coextruded using a device in which a T-die for coextrusion was attached to the tip of two extruders. At this time, the material of Reference Example 1 was used in an extruder with an inner diameter of 25 mm, and the material of Reference Example 2 was used in an extruder with an inner diameter of 40 mm.
Each sample was extruded at 320° C. using a 1.0 mm extruder.

This melt-extruded sheet was brought into close contact with a cooling roll at 63° C. by electrostatic charging, and cooled and solidified. The cooling rate at this time was an average of 55°C/sec to obtain a stretched sheet of 130 μm. This sheet was stretched between rolls at 110°C2 at a stretching speed of 6,000% in the longitudinal direction by changing the circumferential speed of each roll.
The film was stretched 3 times at a speed of 1/min. Subsequently, the film was stretched 3 times in the transverse direction using a tenter at 120° C. and at a stretching rate of 6000%/min.

Furthermore, while fixing it horizontally with a tenter, vertically, 13
It was re-stretched to 1.5 times at 0°C and 2000%/min. This film was fixed on a tenter and slightly loosened, 255°
C. for 10 seconds.

The resulting film had a thickness of 12 μm. The surface roughness of this film was measured according to JIS B-0601 at a cutoff value of 0.08 mm.

In addition, the static friction coefficient was measured according to ASTM D-1894. The properties of the obtained film are shown in the table.

Example 2 A styrenic polymer composition was prepared in the same manner as in Reference Example 1, except that silica with an average particle size of 0.9 μm (Jilton AMT-08, manufactured by Mizusawa Chemical Industry) was used as the silica. Prepared.

Next, in Example 1, instead of the material of Reference Example 1,
The same operation as in Example 1 was performed except that this styrenic polymer composition was used. The results are shown in the table.

Example 3 Using the styrene polymer pellets of Reference Example 2, a stretched film was produced in the same manner as in Example 1, except that a 50/150/400/150150 mesh was placed in the extruder. This film was corona treated. Next, JP-A-1
0 of the syndiotactic structure styrene-divinylbenzene copolymer obtained in Example 1 of Publication No.-95113 (9.4 mol% of syndiotactic units, 5.0 mol% of ethylbenzene units, 9 weight average molecular weight: 360.000)
．． A 5 wt% chloroform solution was prepared, and 0.5 wt% of dry process silica (Aerosil TT-97 manufactured by Nippon Aerosil) was added to the styrene-divinylbenzene copolymer.
Secondary particles having a particle size of 0.3 μm) were added thereto and mixed uniformly in a cylindrical container using a homomixer L type (manufactured by Tokushu Kika Kogyo Co., Ltd.) to form a slurry solution. This slurry solution was applied to the above film using a bar coater, and heated at 250°C for 10 minutes.
Dry for seconds.

The properties of the obtained film are shown in the table.

Example 4 In Example 3, the same operation as in Example 3 was performed except that silica (manufactured by Mizusawa Chemical Industries, Ltd., Jiruton AMT-08) having an average particle size of 0.9 μm was used as the silica. The results are shown in the table.

Comparative example 1 The properties of the film of Example 3 before coating were investigated.

The results are shown in the table.

Comparative Example 2 The same operation as in Example 1 was performed except that a single layer film was created using the material of Reference Example 1. The results are shown in the table.

(The following is a blank space) [Effects of the Invention] As shown in the ridges, the film of the present invention has excellent heat resistance, has a highly smooth surface, and also has good slip properties.

Therefore, the film of the present invention can be used as a magnetic tape.

It is expected to be effectively used as a film base material for magnetic disks, FPCs, photographic films, etc., as well as various industrial films such as capacitors.

Claims (5)

[Claims] (1) A stretched film of a styrenic polymer having a syndiotactic structure or a composition thereof, or a laminated film containing the stretched film, wherein one side is a rough surface and the other side is a smooth surface, and the surface of the smooth surface Roughness Ra is 0.001~0
．． 02 μm, and the film has a static friction coefficient μs of 0.3 to 1.0. (2) The slippery film according to claim 1, wherein the ratio of surface roughness between the rough surface and the smooth surface is 1.5 to 10. (3) A resin layer on one side of a layer mainly composed of a styrenic polymer having a syndiotactic structure with a residual aluminum content of 3000 ppm or less, a residual titanium content of 10 ppm or less, and a residual styrene monomer content of 7000 ppm or less. The slippery film according to claim 1, comprising a laminated resin layer containing and/or inorganic particles. (4) (a) A styrenic polymer having a syndiotactic structure with a residual aluminum content of 3000 ppm or less, a residual titanium content of 10 ppm or less, and a residual styrenic monomer content of 7000 ppm or less, and (b) a syndiotactic structure. The styrenic polymer has an average particle size of 0.01~
4. The method for producing an easily slippery film according to claim 3, wherein a composition comprising inorganic particles of 3 μm is coextruded while being heated and melted, and then stretched. (5) Dissolved on one side of a stretched film mainly composed of a styrenic polymer having a syndiotactic structure with a residual aluminum content of 3000 ppm or less, a residual titanium content of 10 ppm or less, and a residual styrene monomer content of 7000 ppm or less. 4. The method for producing an easily slippery film according to claim 3, further comprising applying a resin containing a resin and/or an inorganic particle.