JPH06207036A - Polystyrene film - Google Patents

Abstract

PURPOSE:To provide a polystyrene film which has a thin layer of, e.g., metal or metal oxide on the surface of the base film and is thermally stable without causing heat shrinkage even at high temperature, excellent in traveling characteristics and abrasion resistance, and free from the occurrence of scrapings on the surface of the thin layer in traveling. CONSTITUTION:The film has a base film made of a resin composition containing a syndiotactic polystyrene polymer and has a thin layer provided at least on one side of the base film. The heat shrinkage of the title film at 200 deg.C is at most 3%; the surface of the thin layer is substantially free from projections of 1mum or greater; and the three-dimensional surface roughness SDELTAa of the thin layer is 0.004 to 0.04.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polystyrene film having a thin film of metal, metal oxide, etc. on its surface.
More specifically, it is excellent in thermal stability, has good running properties when running the long film by winding, etc., and has sufficient abrasion resistance. The present invention relates to a polystyrene film that does not generate shavings.

[0002]

2. Description of the Related Art A laminated film having a metal or metal oxide thin film formed on the surface of a polystyrene film is used as various industrial films, packaging films, magnetic tape films and the like. It is desirable that the polystyrene film serving as the base film of such a laminated film is excellent in mechanical properties, chemical resistance, electrical properties such as dielectric loss and dielectric constant, and transparency. Recently, it was revealed that a polystyrene polymer having a syndiotactic structure is a material having excellent crystallinity, thermal stability and solvent resistance (Japanese Patent Publication No. 3-7685).
-110122, JP 1-168709 A, JP 1-182346 A, JP 2-279 A.
No. 731, No. 3-74437, No. 3
-109453, JP-A-3-99828,
JP-A-3-124427 and JP-A-3-131
Japanese Patent No. 644 discloses a stretched film using a polystyrene polymer having a syndiotactic structure. These films can be used by themselves as various industrial and packaging films, and further, they are disclosed in JP-A-Hei-2.
Japanese Patent Publication No. 143851 discloses a film in which a metal thin film layer is provided on the above stretched film.

Generally, when a thin film layer of a metal or a metal oxide is provided on a film by vapor deposition, sputtering or the like, the film is required to have a property that it does not shrink even at a high temperature. In order for the polystyrene-based film having a syndiotactic structure to have the property that it does not shrink even at high temperatures, it is necessary to heat-set it at a high temperature for a relatively long time during the preparation of the film. However, a polystyrene film having a syndiotactic structure is fragile and easily scraped, and
The heat setting for a long time at a high temperature makes it easier for the film to be scraped during the operation during film formation or vapor deposition. As a result, the film dust generated by the scraping deteriorates various characteristics of the film. For example, in the case of a gas barrier film, the gas barrier property becomes low,
In the case of a magnetic tape, dropout (loss of signal) occurs, and in the case of a film for capacitors, dielectric breakdown occurs.

Further, in general, in order to improve the running property when winding a long film, a film is formed by using a polymer to which organic or inorganic fine particles are added, and projections are formed on the surface. It is known to get a good film. However, in this film, when the projections are large, the projections themselves deteriorate the characteristics of the film,
Moreover, the projections are scraped off when the film is running, and the generated powder further deteriorates the properties of the film.

[0005]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and an object thereof is to provide a polystyrene-based base film having a polystyrene layer having a thin film layer of metal, metal oxide or the like. To provide a polystyrene film which is a film, has no heat shrinkage even at high temperature, has good running property and abrasion resistance, and does not generate abrasion powder due to friction when the base film or thin film layer is running. It is in.

[0006]

A polystyrene film of the present invention is provided on at least one surface of a base film made of a resin composition containing a polystyrene polymer having a syndiotactic structure. A polystyrene-based film containing a thin film layer, wherein the polystyrene-based film has a heat shrinkage ratio at 200 ° C. of 3% or less; and a protrusion of substantially 1 μm or more on the surface of the thin-film layer of the polystyrene-based film. And the three-dimensional surface roughness SΔa of the thin film layer of the polystyrene-based film is 0.004 to 0.04, which achieves the above object.

Next, the present invention will be described in detail.

The polystyrene film of the present invention comprises a base film and a thin film layer provided on at least one surface of the base film.

The base film is made of a resin composition containing a polystyrene polymer having a syndiotactic structure. Here, the syndiotactic structure has a molecular structure in which an asymmetric carbon atom is present at every other carbon atom of the main chain, and the substituents are alternately d-type and l-type to the asymmetric carbon atom. It refers to a three-dimensional structure that is connected by a pattern. The polystyrene-based polymer having a syndiotactic structure used in the present invention means that a phenyl group or a substituted phenyl group is alternately d-type with respect to an asymmetric carbon atom existing in every other carbon atom of the main chain. It is arranged in l-type,
It is a polystyrene polymer. Generally, polystyrene polymers have high transparency, but poor thermal stability and chemical resistance. However, the polystyrene polymer having a syndiotactic structure is excellent in thermal stability and chemical resistance, and has high transparency.

In the polystyrene polymer having the syndiotactic structure, the tacticity of the side chain phenyl group or substituted phenyl group measured by the nuclear magnetic resonance method is 8 if the unit of the polymer is 2)
5% or more, 50 when the polystyrene-based polymer is pentat (5 types of units constituting the polystyrene-based polymer)
% Or more is preferable.

Examples of the polystyrene-based polymer include polystyrene; poly (p-, m- or o-methylstyrene), poly (2,4-, 2,5-, 3,4- or 3,
5-dimethylstyrene), poly (p-tert-butylstyrene), and other poly (alkylstyrenes); poly (p
-, M- or o-chlorostyrene), poly (p-, m
-Or o-bromostyrene), poly (p-, m- or o-fluorostyrene), poly (o-methyl-p-fluorostyrene) and the like poly (halogenated styrene); poly (p-, m-or poly (halogenated alkylstyrene) such as o-chloromethylstyrene); poly (p-, m
-Or o-methoxystyrene), poly (p-, m- or o-ethoxystyrene) and other poly (alkoxystyrene); poly (p-, m- or o-carboxymethylstyrene) and other poly (carboxy) Alkyl styrene); poly (alkyl ether styrene) such as poly (p-vinylbenzyl propyl ether); poly (alkyl silyl styrene) such as poly (p-trimethylsilyl styrene); poly (vinyl benzyl dimethoxyphosphite) and the like. . Of these, polystyrene is particularly preferable. Furthermore, the polystyrene-based polymer may be used alone or in combination of two or more kinds. Furthermore, if the polystyrene polymer is a syndiotactic structure having a tacticity in the above range, a mixture with a polystyrene polymer having an atactic structure or an isotactic structure, a copolymer or a mixture thereof, Good. Here, the atactic structure is a three-dimensional structure in which the molecular structure is such that substituents are randomly arranged in d-type and l-type with respect to asymmetric carbon atoms present in every other carbon atom of the main chain. Is. The isotactic structure means that the molecular structure is such that the substituents are only d-type or l with respect to an asymmetric carbon atom existing in every other carbon atom of the main chain.
It is a three-dimensional structure arranged only in the mold.

The weight average molecular weight of the polystyrene polymer is preferably 10,000 or more, more preferably 5 or more.
It is 0000 or more. If the polystyrene-based polymer has a weight average molecular weight of less than 10,000, it may not be possible to obtain a film having strong elongation properties and thermal stability. The upper limit of the weight average molecular weight is not particularly limited, but when it is 1500000 or more, the obtained film is
It is not preferable because there is a risk of breakage as the stretching tension increases.

The resin composition containing the polystyrene-based polymer contains inert particles in addition to the polystyrene-based polymer in order to impart slipperiness to the surface of the obtained polystyrene-based film. Good. The inert particles may be organic particles or inorganic particles. Examples of the material of the inorganic inert particles include metal oxides such as silica, titanium dioxide, talc, and kaolinite; salts of metals such as calcium carbonate, calcium phosphate, and barium sulfate. Examples of the material of the organic inert particles include polymers such as crosslinked polystyrene resin, crosslinked acrylic resin, benzoguanamine resin, silicone resin, and crosslinked polyester resin. These inert particles may be contained alone or in combination of two or more kinds.

The average particle size of the inert particles is 0.01 to
3.5 μm is preferable. Further, the degree of variation in particle size of the inert particles is preferably 25% or less. Here, the variation degree of the particle diameter is expressed by the standard deviation of the particle diameter / the average particle diameter. Furthermore, the content of the above-mentioned inert particles is 0.005 to 2.
0 parts by weight is preferable, and 0.005 to 1.0 parts by weight is particularly preferable. Further, the shape of the above-mentioned inert particles is that at least one kind of the inert particles having an area shape factor represented by the following formula is 60% or more is contained from the viewpoint of running property of the obtained film. preferable. However, when the film of the present invention is used for a capacitor, it is preferable to contain inert particles having an area shape factor represented by the following formula of 80% or less from the viewpoint of dielectric breakdown characteristics. .

[0015]

[Equation 1]

If desired, the resin composition containing the polystyrene polymer may contain known additives such as antioxidants and antistatic agents. The content of the additive is preferably 10 parts by weight or less based on 100 parts by weight of the polystyrene polymer. If the content of the additive is more than 10 parts by weight, there is a risk that the unstretched film made of the resin composition containing the polystyrene-based polymer may be broken during stretching.

The polystyrene film of the present invention has a thin film layer of metal and / or metal oxide on at least one surface of the base film.

The material of the thin film layer is not particularly limited and is determined depending on the use of the polystyrene film obtained. For example, for magnetic recording media, the material of the thin film layer includes Co, Ni, Cr, Fe and alloys thereof or oxides of these metals, and for capacitors,
Examples of the material of the thin film layer include metals such as Al and Zn,
Further for transparent conductive film, the material of the thin film layer,
Examples thereof include indium oxide, tin oxide and gold.

In the polystyrene film of the present invention, if necessary, various known functions such as antistatic can be provided between the base film and the thin film layer or on the surface of the base film on which the thin film layer is not provided. , Easy adhesion,
It is possible to provide a coating layer or the like capable of imparting easy sliding property or abrasion resistance during traveling. In order to form such a coating layer, for example, a method of forming by an in-line coating method during film formation, or a method of forming by an off-line coating method after stretching and heat setting of the film are adopted.

The method for producing the polystyrene film of the present invention is not particularly limited, and any method can be adopted. For example, there are the following production methods. First, a base film is prepared using the polystyrene polymer having the syndiotactic structure. At the time of preparing the base film, it is recommended to add the above-mentioned inert particles in order to form protrusions on the film surface. The base film is
For example, it is formed by biaxial stretching in the longitudinal and transverse directions by a conventional method. In addition to the sequential stretching method in which longitudinal stretching and transverse stretching are performed in order, transverse / longitudinal / longitudinal stretching method, longitudinal / lateral / longitudinal stretching method, longitudinal / longitudinal stretching method
A stretching method such as a transverse stretching method is adopted. After biaxially stretching the polystyrene film, heat treatment is performed in a tenter. After the heat treatment, relaxation treatment may be performed in the horizontal direction and the vertical direction.

The polystyrene film of the present invention may be required to have excellent heat stability at high temperatures. In that case, in addition to the stretching method at the time of preparing the base film, the stretching conditions greatly affect the thermal stability at high temperatures. Especially, the heat shrinkage at 200 ℃ is 3%
In order to have excellent thermal stability, such as
The heat setting treatment is performed from the cold crystallization temperature to the melting point, preferably 200.
Performed in the range of ℃ to melting point, longitudinal relaxation treatment and transverse relaxation treatment from the glass transition point to heat setting temperature, preferably 150 ° C.
It is desirable to carry out in the range of to set temperature. Then
A thin film layer is formed on the base film obtained as described above. The method for forming the thin film layer depends on the type of thin film to be formed, and includes a vacuum vapor deposition method, an ion plating method, a sputtering method, a plasma vapor deposition method, a plating method, a coating method, a film lamination method, and the like. For example, a thin film of metal, metal oxide, etc. can be suitably formed by a vacuum vapor deposition method, an ion plating method, a sputtering method, a plasma vapor deposition method, or the like.

The thin film layer of the polystyrene film of the present invention depends on the heat setting treatment, relaxation treatment and stretching treatment conditions when forming the base film, and the type, addition amount, average particle diameter, degree of variation and shape of the inert particles. A film having a three-dimensional surface roughness SΔa of 0.004 to 0.04, substantially no protrusions of 1 μm or more, and excellent thermal stability can be obtained.

The heat shrinkage of the polystyrene film thus obtained at 200 ° C. is 3% or less, preferably 2% or less, more preferably 1% or less. Two
When the heat shrinkage ratio at 00 ° C. exceeds 3%, wrinkles are generated when the thin film layer is formed by, for example, vapor deposition or sputtering, and the flatness of the formed thin film is deteriorated, which is not preferable. Here, if the film is exposed to a high temperature for a long time in order to reduce the heat shrinkage rate, the brittleness increases and the abrasion resistance becomes poor. Therefore, a relaxation treatment should be performed after the longitudinal stretching treatment, and the heat setting temperature and time should be within a certain range. It is preferable to keep the temperature at 0.degree. C., and if necessary, perform lateral and / or longitudinal relaxation treatment after heat setting treatment. Here, the longitudinal relaxation treatment after the longitudinal stretching is performed at a temperature equal to or higher than the stretching temperature and lower than the melting point so that the shrinkage rate of the film after the longitudinal relaxation treatment at 150 ° C. is 5% or less, and the heat setting treatment is 220 ° C. It is preferable to perform the treatment at a temperature below the melting point within 30 seconds, preferably within 10 seconds, and the relaxation treatment in the lateral and longitudinal directions is preferably performed at a temperature not higher than the maximum temperature of the heat setting treatment so that the flatness is not disturbed.

As described above, the polystyrene film of the present invention thus formed has substantially no protrusions of 1 μm or more on its surface. If there are protrusions of 1 μm or more, the protrusions themselves become defects such as scratches and pinholes, and the protrusions fall off from the film when the film is running, and the generated powder causes scratches and pinholes in the thin film.

The three-dimensional surface roughness SΔa of at least one surface of the polystyrene film of the present invention is as described above.
It is in the range of 0.004 to 0.04. SΔa is 0.0
If it is less than 04, friction increases when running a long film, resulting in poor runnability. Friction is increased due to contact with rolls, etc., causing scraping. S
When Δa exceeds 0.04, the abrasion resistance is lowered, and even if the same force is applied, abrasion occurs, and the abrasion powder causes scratches on the film, which is not preferable.

As described above, in the polystyrene film of the present invention, the heat shrinkage rate and the surface roughness satisfy the predetermined conditions. Therefore, even when the film is run, shavings of the film are generated on the surface of the thin film layer. It does not occur and therefore the various properties of the film (gas barrier properties, no dropout, etc.) are good.

[0027]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. The methods for measuring the properties of the polystyrene-based films prepared in Examples and Comparative Examples and the inert particles used are shown below.

1) Thermal Shrinkage of Polystyrene-based Film at 200 ° C. The polystyrene-based film was allowed to stand in an atmosphere of 200 ° C. for 30 minutes in a tensionless state, and then the shrinkage of this film was measured.

2) Three-dimensional surface roughness SΔa of polystyrene-based film The surface of the polystyrene-based film was measured using a stylus-type three-dimensional surface roughness meter (SE-3AK, Kosaka Laboratory Ltd.).
A cut-off value of 0.25 m in the longitudinal direction of the polystyrene film under the conditions of a needle radius of 2 μm and a load of 30 mg.
m, the surface roughness was measured 500 times continuously at 2 μm intervals, that is, over 1 mm. The height of each point was incorporated into a three-dimensional roughness analyzer (SPA-11).

In the direction perpendicular to the longitudinal direction of the polystyrene-based film, the surface in the longitudinal direction of the above-mentioned polystyrene-based film was measured except that the surface roughness was continuously measured 150 times at intervals of 2 μm, that is, 0.3 mm. It carried out similarly to the measurement of roughness.

The obtained data is loaded into an analyzer,
Using the analyzer, SΔa was determined.

3) Number of protrusions on the surface of polystyrene film After thinly and uniformly depositing aluminum on the surface of the base film, interference fringes on the surface of this polystyrene film are
Using a ^two- beam interference microscope (manufactured by Nache), the area of 1 mm ² was observed at 400 times. This interference fringe corresponds to the height of the protrusion, and it is determined that the protrusion is higher as the number of stripes on the ring formed around the protrusion increases.

4) Average Particle Size of Inert Particles and Variation in Particle Size The inert particles were observed with a S-510 type scanning electron microscope (manufactured by Hitachi Ltd.), and a photographed one was enlarged. Copies were made, the outline of the inert particles was traced, and optionally 200 particles were painted black. For each particle, the Feret diameter in the horizontal direction of the trace image filled in black was measured by using an image analyzer (Luzex 500, manufactured by Nicol). The average value of these measured values was defined as the average particle size. Further, the standard deviation of the granulometer was determined from this measured value, and the degree of particle dispersion was determined from the following formula.

[0034]

[Equation 2]

5) Area Shape Factor of Inert Particles A trace image of 20 particles is arbitrarily selected from the trace images of the inert particles used in the measurement of the average particle diameter of the inert particles,
The projected cross-sectional area of each particle was measured by using an image analyzer (Luzex 500, manufactured by Nicole). Further, the area of the circumscribing circle for each particle was calculated using the above trace image, and the area shape factor of the particle was calculated from the following formula.

[0036]

[Equation 3]

6) Running property and abrasion resistance of polystyrene film Evaluation was performed using the apparatus shown in FIG. A long film 1 was obtained by slitting a polystyrene film in a narrow width and winding the film on a roll. As shown in FIG. 1, this was run through a metal roll (capstan) 21 and a fixed metal pin 23. The tension of the base film after passing the guide roll with respect to a constant supply tension was measured by the tension detecting device 22. The tension and the presence or absence of scratches were each evaluated in 5 grades as shown below, and this was used as the evaluation of runnability. The amount of white powder adhering to the guide roll after passing through the guide roll was also evaluated in five levels as shown below, and this was taken as the evaluation of wear resistance.

Evaluation of runnability 1st class ・ ・ Large tension, very many scratches 2nd class ・ ・ Slightly large tension, many scratches 3rd class ・ ・ Slightly scratched during tension 4th class ・ ・ Slightly small tension, almost no scratches 5 Grade ... Small tension, no scratches.

If the ranks of the results obtained by the tension and the abrasion are different, the worse rank is adopted.

Evaluation of abrasion resistance 1st grade: White powder is generated very much 2nd grade: White powder is generated 3rd grade: White powder is slightly generated 4th grade: White powder is hardly generated 5th grade: White powder No occurrence.

7) Number of Thin Film Defects of Polystyrene-Based Film Co-Ni alloy was vapor-deposited to a thickness of 1500 Å to form a thin-film layer, and the polystyrene-based film having the thin-film layer was slit to a width of 1/2 inch. This film was mounted on a VHS type video tape recorder, and the number of dropouts was measured using a dropout counter. This was relatively evaluated.

8) Planarity of polystyrene film A Co-Ni alloy was vapor-deposited to a thickness of 1500 Å to form a thin film layer, and the polystyrene film having the thin film layer was slit into a width of 50 cm. This film was unwound from a roll for a length of 200 cm, and the flatness of this film was visually observed to make a 5-grade evaluation.

Grade 1 ... Waves are present on the entire surface of the film even when a strong tension is applied. Grade 2 ... Waves are present on a part of the film even when a strong tension is applied. Class 3 ... No waviness when a strong tension is applied. 4 Grade: No waviness when weak tension is applied. Grade 5: No waviness even when tension is not applied.

Examples 1 to 3 As the inert particles, the average particle size is 0.5 μm and the variation degree is 2
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. The weight ratio of the polymer chip containing the above-mentioned inert particles to the polymer chip not containing the inert particles is 0.2: 9.8 (Example 1), 1: 9 (Example 2),
After mixing at a ratio of 2.8 to 7.2 (Example 3), it was dried and melted at 305 ° C. This is extruded from a T-die having a 800 μm thick lip gap die, and then
By an electrostatic application method, this was brought into close contact with a cooling roll at 50 ° C. and cooled and solidified to obtain an amorphous film having a thickness of 140 μm.

The above amorphous film was rolled with a roll 95
Preheat to ℃, then the film surface temperature 700 ℃
4 infrared heaters are used to heat the film at a film temperature of 130 ° C. and stretch it 3.5 times in the longitudinal direction. The film is inserted between a ceramic roll at 150 ° C. and a metal roll at 40 ° C. A 12% relaxation treatment was applied in the longitudinal direction.
Next, this film was preheated to 120 ° C. in a tenter and stretched 3.3 times in the direction orthogonal to the longitudinal direction at a film temperature of 120 ° C., and this film was further heated at 260 ° C. to 12 ° C.
It was heat set for 2 seconds. Then, this film was subjected to a relaxation treatment at 215 ° C. in a direction orthogonal to the longitudinal direction by 3%, and then 21
It was subjected to 2% relaxation treatment in the longitudinal direction at 0 ° C. The thickness of the obtained stretched base film was 14 μm. The characteristics of this base film are shown in Table 1. On one surface of this base film, a Co—Ni alloy was deposited to a thickness of 1500 Å to form a thin film layer. The number of thin film defects and the flatness of the obtained film were evaluated. The results are shown in Table 1. Furthermore, the above-mentioned base film has a coefficient of humidity expansion of 5 × 10 ⁻⁷ /% RH and a coefficient of thermal expansion of 2 × 10 ⁻⁵ / ° C.
The film has excellent dimensional stability of the film due to environmental changes during processing or use of the film after forming the thin film layer, and peeling of the thin film layer due to environmental changes of the film, film having a thin film layer No cracks, sledges or waviness were observed.

Comparative Examples 1 and 2 As the inert particles, the average particle size is 0.5 μm, and the variation degree is 2.
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. After mixing the above-mentioned polymer chip containing the inert particles and the polymer chip not containing the inert particles in a weight ratio of 0.1: 9.9 (Comparative Example 1), 3: 7 (Comparative Example 2). , Dried and melted at 305 ° C. This is extruded from a T-die having a lip gap die with a thickness of 800 μm, and then this is heated to 50 ° C. by an electrostatic application method.
It is made to adhere to the cooling roll of, and solidified by cooling to a thickness of 140μ.
The same operation as in Example 1 was performed except that an amorphous film of m was obtained. The thickness of the obtained stretched base film was 14 μm. On one surface of this base film,
A Co-Ni alloy was deposited to a thickness of 1500 Å to form a thin film layer. No peeling of the thin film layer due to environmental changes of the obtained film, cracking of the film having the thin film layer, warpage, waviness and the like occurred. Table 1 shows the physical properties of the obtained film.

Comparative Example 3 As the inert particles, the average particle size is 0.5 μm and the variation degree is 5
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. The above-described polymer chip containing the inert particles and the polymer chip not containing the inert particles were mixed at a weight ratio of 1: 9, dried, and melted at 305 ° C. This was extruded from a T-die having a lip gap die having a thickness of 800 μm, and then adhered to a cooling roll at 50 ° C. by an electrostatic application method to be cooled and solidified to obtain an amorphous film having a thickness of 140 μm. The same operation as in Example 1 was performed except for the above. The thickness of the obtained stretched base film was 14 μm. On one surface of this base film, a Co—Ni alloy was deposited to a thickness of 1500 Å to form a thin film layer. No peeling of the thin film layer due to environmental changes of the obtained film, cracking of the film having the thin film layer, warpage, waviness and the like occurred. Table 1 shows the physical properties of the obtained film.

Example 4 As the inert particles, the average particle size is 0.5 μm and the variation degree is 2
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. The above-described polymer chip containing the inert particles and the polymer chip not containing the inert particles were mixed at a weight ratio of 1: 9, dried, and melted at 305 ° C. This was extruded from a T-die having a lip gap die with a thickness of 800 μm, and then adhered to a cooling roll at 50 ° C. by an electrostatic application method to be cooled and solidified to obtain an amorphous film with a thickness of 140 μm. It was The above amorphous film was heated to a film temperature of 103 ° C. by a roll, stretched 3.5 times in the longitudinal direction, and then subjected to a 12% relaxation treatment in the longitudinal direction between a ceramic roll at 150 ° C. and a metal roll at 40 ° C. After that, the film is heated to 120 ° C with a tenter.
It was preheated to, and stretched 3.3 times in a direction orthogonal to the longitudinal direction at a stretching temperature of 120 ° C., and heat-treated and fixed at 260 ° C. for 12 seconds.
After that, the same operation as in Example 1 was performed except that 3% relaxation treatment was performed at 215 ° C in the direction orthogonal to the longitudinal direction, and further 2% relaxation treatment was performed at 210 ° C in the longitudinal direction. The thickness of the obtained stretched base film was 14 μm. On one surface of this base film, a Co—Ni alloy was vapor-deposited to a thickness of 1500 Å to form a thin film layer, and as a result, waviness was generated in the film. Table 1 shows the physical properties of the obtained film.

Comparative Example 4 As the inert particles, the average particle size is 0.5 μm, and the variation degree is 2
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. The above-described polymer chip containing the inert particles and the polymer chip not containing the inert particles were mixed at a weight ratio of 1: 9, dried, and melted at 305 ° C. This is extruded from a T-die having a lip gap die with a thickness of 800 μm, and then adhered to a cooling roll at 50 ° C. by an electrostatic application method to be cooled and solidified to obtain an amorphous film with a thickness of 130 μm. It was

The above amorphous film was rolled with a roll 1
The film is heated to 03 ° C., then, the film is heated by a roll and stretched 3.5 times in the longitudinal direction at a film temperature of 103 ° C., and then the film is preheated to 120 ° C. with a tenter,
The film was drawn 3.3 times in the direction orthogonal to the longitudinal direction at a drawing temperature of 120 ° C., and heat-treated and fixed at 260 ° C. for 12 seconds. Then 2
The same operation as in Example 1 was performed, except that 3% relaxation treatment was performed at 15 ° C in the direction orthogonal to the longitudinal direction, and further 2% relaxation treatment was performed at 210 ° C in the longitudinal direction. The thickness of the obtained stretched base film was 14 μm. On one surface of this base film, a Co—Ni alloy was vapor-deposited to a thickness of 1500 Å to form a thin film layer, and as a result, waviness was generated in the film. Table 1 shows the physical properties of the obtained film.

Comparative Example 5 As the inert particles, the average particle size is 0.5 μm and the variation degree is 5
0% silica having an area shape factor of 80% was converted into polystyrene having a syndiotactic structure (weight average molecular weight 300
000) A polymer chip containing 0.5 parts by weight based on 100 parts by weight was prepared. Separately, a polymer chip of the above polystyrene containing no inert particles was prepared. The above-described polymer chip containing the inert particles and the polymer chip not containing the inert particles were mixed at a weight ratio of 1: 9, dried, and melted at 305 ° C. This is extruded from a T-die having a lip gap die having a thickness of 800 μm, and then adhered to a cooling roll at 50 ° C. by an electrostatic application method to be cooled and solidified to obtain an amorphous film having a thickness of 120 μm. It was

The above amorphous film was rolled by a roll 1
The film was heated to 03 ° C., stretched 3.0 times in the longitudinal direction, and the film was heat set at 270 ° C. for 20 seconds. The same operation as in Example 1 was performed except that the relaxation treatment after the heat setting treatment was not performed. The thickness of the obtained stretched base film was 14 μm. The characteristics of this base film are shown in Table 1.

[0053]

[Table 1]

From Table 1, it can be seen that the polystyrene films having the base film and the thin film layer obtained in Examples 1 to 4 show dimensional stability of the film due to environmental changes during processing of the film after forming the thin film layer or during use. Moreover, peeling of the thin film layer due to environmental changes of the film, cracking of the film having the thin film layer, warpage and waviness did not occur.

[0055]

As is apparent from the above description, the polystyrene film of the present invention has a metal on the surface of the base film,
It has a thin film of metal oxide, etc., has thermal stability (no heat shrinkage even at high temperature), is excellent in running property and wear resistance, and does not generate shavings on the surface of the thin film layer during running. This film is used for capacitors, magnetic recording media, transparent conductive films,
It is used for flexible printed boards, gas barrier films, flexible solar cells, etc.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus used for evaluating the running property and abrasion resistance of a film.

[Explanation of symbols]

 1 Film 21 Capstan 22 Tension Detecting Device 23 Fixed Metal Pin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Okuhira 2-1-1 Katata, Otsu, Shiga Prefecture Toyobo Co., Ltd.

Claims (1)

[Claims] 1. A base film comprising a resin composition containing a polystyrene polymer having a syndiotactic structure, and a metal and / or metal oxide thin film layer provided on at least one surface of the base film. A polystyrene-based film containing: a polystyrene-based film having a heat shrinkage ratio at 200 ° C. of 3% or less, and substantially 1 μm on the surface of the thin-film layer of the polystyrene-based film.
There is no protrusion of m or more, and the three-dimensional surface roughness SΔa of the thin film layer of the polystyrene-based film is 0.004 to 0.0.
4 is a polystyrene-based film.