JP2001328219A - Polystyrenic laminated film and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polystyrenic laminated film having high transparency and excellent not only in heat resistance, oil resistance and mechanical strength but also in both of thermal processability (thermal moldability) and transparency. SOLUTION: The polystyrenic laminated film is constituted by laminating A-layers (comprising a styrenic polymer which has a syndiotactic structure and of which the degree of crystallization is 20% or more or a resin composition containing the same) on both surfaces of a B-layer (comprising a styrenic polymer having an atactic structure or a resin composition containing the same) and the total haze of the laminated film is 10% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a polystyrene-based laminated film, and more particularly, to transparency, heat resistance,
The present invention relates to a polystyrene-based laminated film which is useful as various films, bags and containers for daily necessities and industry because of its excellent oil resistance and good thermal processing suitability (thermoformability).

[0002]

2. Description of the Related Art A styrene-based polymer having a syndiotactic structure (hereinafter, may be abbreviated as "SPS") is a film having mechanical strength, heat resistance, appearance, solvent resistance, moisture resistance and the like. Because of its excellent physical properties, various films such as food, medicine, stationery, daily necessities, etc., packaging films, bags and containers, photographic films, release films, adhesive tapes, condenser films, etc. Used or expected to be used for applications.

Further, in order to provide various functions by providing an SPS layer, a laminated film of polyester, polycarbonate, polyamide, and polyphenylene sulfide (Japanese Patent Laid-Open No. 1-262132), and a laminate of ethylene-vinyl alcohol copolymer ( JP-A-2-192942), a laminated film with a metal thin film (JP-A-2-143851), and a laminate with polyvinylidene chloride (JP-A-3-12655)
5), a laminate with a rubber-based pressure-sensitive adhesive (JP-A-4-26148)
5) have been proposed.

However, the S used for these various applications is
A PS film and a two- or three-layer laminate using the same have excellent physical, chemical, and mechanical properties such as heat resistance and oil resistance when the film is used as a planar shape, but are suitable for heat processing ( (Thermoformability), and there were problems such as tearing during thermoforming and delamination. Further, a laminate with a rubber-based pressure-sensitive adhesive (JP-A-4-261485) was apt to warp and was not suitable for thermoforming. Further, none of these multilayer films was sufficiently transparent.

[0005] On the other hand, stretched polystyrene films and sheets having an atactic structure are excellent in rigidity, transparency, thermoformability and heat sealing, and are generally used for applications such as container lids. Improvement was desired.

Further, a laminated film of an SPS film and a polystyrene polymer having an atactic structure (Japanese Patent Laid-Open No.
-12516) has been proposed from the viewpoint of imparting heat sealability, but also in this case, the transparency is not necessarily sufficient.
The thermoformability was also insufficient.

[0007]

SUMMARY OF THE INVENTION The present invention has been made from the above viewpoint, and has the heat resistance of the conventional SPS.
To provide a polystyrene-based laminated film excellent in both heat processing suitability (thermoformability) and transparency while maintaining oil resistance and mechanical strength, and a method for efficiently producing such a polystyrene-based laminated film. It is the purpose.

[0008]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, the present invention provides a laminated film comprising a specific combination of films having specific compositions and properties. It has been found that the object of the invention can be effectively achieved, and the present invention has been completed. That is, the gist of the present invention is as follows.

[1] A laminated film in which the following layer A is laminated on both sides of layer B, wherein the total haze of the laminated film is 10% or less. A layer: a layer composed of a styrene polymer having a syndiotactic structure or a resin composition containing the same, wherein the styrene polymer has a crystallinity of 20% or more.

Layer B: A layer made of a styrenic polymer having an atactic structure or a resin composition containing the same. [2] The ratio of the thickness of each layer of layer A / layer B / layer A is 1/1.
The polystyrene-based laminated film according to the above [1], which is 8/1 to 2/1/2.

[3] Between any of the A layer and the B layer,
The polystyrene-based laminated film according to the above [1] or [2], wherein no adhesive is present. [4] The polymer or resin composition to be the A layer and the polymer or resin composition to be the B layer at 290 ° C. and a shear rate of 10 ⁻¹ sec
The melt viscosity ratio at c- ¹ is from 0.3 to 3, and after the melt coextrusion using the polymer or the composition, the film is stretched. The method for producing a polystyrene-based laminated film according to the above.

[0012]

Embodiments of the present invention will be described below. The polystyrene-based laminated film of the present invention is a laminated film composed of an A layer and a B layer, which will be described later, wherein the A layer is laminated on both sides of the B layer. The total haze of the laminated film is 10% or less. It is a polystyrene-based laminated film.

The A layer and the B layer having the specific compositions are referred to as A
By having a layer / layer B / layer A configuration, the transparency and the like are excellent, and at the same time, effects such as excellent heat processing suitability (thermoformability) are exhibited. The term "excellent in thermal processing suitability (thermoformability)" as used in the present invention means that the film before thermoforming or the film does not warp during preheating (flatness),
A property that does not cause breakage, delamination or other problems during thermoforming and does not cause warpage in molded products.

Hereinafter, the contents of each layer constituting the laminated film of the present invention, the layer constitution, the method for producing the laminated film, and the like will be described in detail.

1. A layer The A layer of the present invention is a layer made of SPS or a resin composition containing the same. The syndiotactic structure in SPS refers to a syndiotactic structure, in which a phenyl group which is a side chain to a main chain formed from carbon-carbon bonds is alternately located in the opposite direction. And its tacticity is quantified by nuclear magnetic resonance ( ^13C -NMR) using isotope carbon. Tacticity as measured by the ¹³ C-NMR method is as follows: the abundance ratio of a plurality of continuous structural units, for example, dyad for two, triad for five, and triad for five.
Can be indicated by a pentad, but the SPS referred to in the present invention is usually 75% in racemic dyads.
%, Preferably 85% or more, or 30% or more, preferably 50% or more, in racemic pentad. Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (alkylhalogenated alkyl) having a syndiotacticity of 50% or more. Styrene), poly (alkoxystyrene), poly (vinyl benzoate), hydrogenated polymers thereof and mixtures thereof, or copolymers containing these as a main component. Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tertiarybutylstyrene), poly (phenylstyrene), poly (vinylnaphthalene) , Poly (vinylstyrene), and the like, and poly (halogenated styrene) includes poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like. Examples of poly (halogenated alkylstyrene) include poly (chloromethylstyrene), and examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

Among these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (ethylstyrene), poly (divinylbenzene), and poly (p-methylstyrene). Tertiary butyl styrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p-fluorostyrene), hydrogenated polystyrene and copolymers containing these structural units.

Such SPS can be prepared, for example, using a titanium compound and a condensation product of water and a trialkylaluminum as a catalyst in an inert hydrocarbon solvent or in the absence of a solvent, using a styrene monomer (the styrene polymer described above). (A monomer corresponding to the union) can be produced (JP-A-62-187708). For poly (halogenated alkylstyrene), see JP-A-1-46.
No. 912, these hydrogenated polymers are disclosed in
It can be obtained by the method described in JP-A-8505.

The comonomer in the styrenic copolymer includes, in addition to the above-mentioned styrenic polymer monomers, olefin monomers such as ethylene, propylene, butene, hexene and octene; diene monomers such as butadiene and isoprene; Examples include diene monomers and polar vinyl monomers such as methyl methacrylate, maleic anhydride, and acrylonitrile.

In particular, when the styrene repeating unit is 80 to 100
A styrene-based polymer having a mole% of p-methylstyrene repeating units of 0 to 20 mole% is preferably used. The styrenic polymer is not particularly limited in molecular weight, but has a mass average molecular weight of 10,000 or more,
Preferably it is less than 0000, especially 50,000.
Those having 0 or more and 1,500,000 or less are more preferable. If the weight average molecular weight is less than 10,000, stretching may not be performed sufficiently. Further, regarding the molecular weight distribution, there is no restriction on the width thereof, and various ones can be applied, but the mass average molecular weight (Mw) /
Those having a number average molecular weight (Mn) of 1.5 or more and 8 or less are preferable.

The above-mentioned high SPS is present in the layer A of the present invention.
The content is preferably 0 to 100% by mass, more preferably 80 to 100% by mass, particularly preferably 90 to 100% by mass. As the A layer of the present invention, a thermoplastic resin other than SPS, a thermoplastic elastomer, a compatibilizing agent, and the like can be added to the above-mentioned SPS as long as the purpose thereof is not hindered. These compounding agents may be compounded in the A layer in the range of 0 to 30% by mass, more preferably 0 to 20% by mass, especially 0 to 10% by mass. Further, various additives may be blended in the A layer as needed. Hereinafter, these compounding agents and additives will be described.

(1-1) Thermoplastic resins other than SPS The thermoplastic resins other than SPS which may be used in the present invention include linear high-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, Isotactic polypropylene, syndiotactic polypropylene, block polypropylene, random polypropylene, polybutene, 1,2-polybutadiene, poly4-methylpentene, cyclic polyolefin and polyolefin resins represented by copolymers thereof, atactic polystyrene, Isotactic polystyrene, HIPS, AB
S, AS, styrene-methacrylic acid copolymer, styrene-methacrylic acid-alkyl ester copolymer, styrene-methacrylic acid-glycidyl ester copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid-alkyl ester copolymer Polymers, polystyrene resins represented by styrene-maleic acid copolymers, styrene-fumaric acid copolymers, polyester resins such as polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyamide 6, polyamide 6,6 It can be arbitrarily selected from known polyamide resins, polyphenylene ethers, PPS and the like. These thermoplastic resins alone, alone,
Alternatively, two or more kinds can be used in combination.

(1-2) Thermoplastic Elastomer Specific examples of the thermoplastic elastomer that may be used in the present invention include, for example, natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene (registered trademark), polysulfide rubber, and thiochol rubber. Acryl rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer ( SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene Block copolymers (SI
S), styrene rubbers such as hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), linear low-density polyethylene elastomers, etc. Olefin rubber or butadiene-acrylonitrile-styrene-core-shell rubber (ABS), methyl methacrylate-butadiene-styrene-core-shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core-shell rubber (MAS), octyl acrylate-butadiene-styrene Core-shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene-core-shell rubber (ABS), butadiene-styrene-core-shell rubber (SBR) , Methyl methacrylate - butyl acrylate - particulate elastic material of the core-shell type siloxane containing core shell rubber including the siloxane, or rubber obtained by modifying them. These can be used alone or in combination of two or more.

(1-3) Compatibilizer The compatibilizer that may be used in the present invention is, for example, a copolymer containing a styrene structure, and the styrene structure in the molecule is 40 mol% or more, preferably 50 mol% or more. It is a polymer containing at least mol%. Specific examples of such a compatibilizer include, for example, styrene-butadiene block copolymer (SBR),
Hydrogenated styrene-butadiene block copolymer (SE
B), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer Copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), and the like. These are all polymers containing a styrene structure in an amount of 50 mol% or more.

(1-4) Various additives Antiblocking agent (AB agent) Examples of the antiblocking agent include the following inorganic particles or organic particles. As the inorganic particles, IA
Group, IIA, IVA, VIA, VIIA, V
Oxides, hydroxides, sulfides, nitrides, halides, carbonates, sulfates, acetates, phosphates, phosphites, organics of Group III, IB, IIB, IIIB and IVB elements Carboxylates, silicates, titanates, borates and their hydrous compounds, composite compounds centered on them, and natural mineral particles are included.

Specifically, compounds of Group IA such as lithium fluoride, borax (sodium borate hydrate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, titanium Magnesium silicate, magnesium silicate, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, titanate Group IIA compounds such as calcium, strontium titanate, barium carbonate, barium phosphate, barium sulfate, barium sulfite, titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia), monoxide Group IVA element compound such as Rukoniumu, molybdenum dioxide, molybdenum trioxide, VIA group elements compound such as molybdenum sulfide, manganese chloride, VII A group element compounds such as manganese acetate, cobalt chloride,
Group VIII element compound such as cobalt acetate, Group IB element compound such as cuprous iodide, Group IIB element compound such as zinc oxide and zinc acetate, aluminum oxide (alumina), aluminum hydroxide, aluminum fluoride, alumina silicate ( Group IIIB element compounds such as silicate alumina, kaolin, kaolinite), silicon oxide (silica, silica gel), graphite,
Examples include IVB group element compounds such as carbon, graphite, and glass, and particles of natural minerals such as kernalite, kainite, mica (mica, kinmo), and virose ore.
Here, the average particle size of the inorganic particles used is 0.1 to 10 μm
Are preferred.

Examples of the organic particles include Teflon (registered trademark), melamine resins, styrene / divinylbenzene copolymers, acrylic resin silicones, and crosslinked products thereof.

These AB agents can be used alone or in combination of two or more.

Antioxidant The antioxidant can be arbitrarily selected from known ones such as phosphorus-based, phenol-based, and sulfur-based. In addition, these antioxidants may be used alone, or
Two or more can be used in combination. Further, preferably, 2- [1-hydroxy-3,5-di-t-
[Pentylphenyl) ethyl] -4,6-di-t-pentylphenyl acrylate.

Nucleating Agents As nucleating agents, metal salts of carboxylic acids such as aluminum di (pt-butylbenzoate) and phosphoric acids such as sodium methylenebis (2,4-di-t-butylphenol) acid phosphate Any of known metal salts, talc, phthalocyanine derivatives and the like can be used. In addition, these nucleating agents can be used alone or in combination of two or more.

Plasticizer Any known plasticizer such as polyethylene glycol, polyamide oligomer, ethylene bisstearamide, phthalic acid ester, polystyrene oligomer, polyethylene wax, or silicone oil can be used. These plasticizers can be used alone or in combination of two or more.

Release Agent The release agent may be arbitrarily selected from known materials such as polyethylene wax, silicone oil, long-chain carboxylic acid, and long-chain carboxylic acid metal salt. These release agents may be used alone or in combination of two or more.

Process Oil In the present invention, in order to improve the elongation, the oil is further added at 40 ° C.
It is preferable to blend a process oil having a kinematic viscosity of 15 to 600 mm ² / s.

Process oils are classified roughly into paraffinic oils, naphthenic oils, and aroma oils depending on the type of oil. Among them, the number of carbon atoms related to paraffin (straight chain) calculated by the ndM method is particularly preferred. Paraffinic oils having a percentage of 60% Cp or more based on the total carbon number are preferred.

The viscosity of the process oil is preferably 15 to 600 mm ² / s at 40 ° C.
500 mm ² / s is more preferred. If the kinematic viscosity of the process oil is less than 15 mm ² / s, it has an effect of improving elongation, but it has a low boiling point and may cause melt-kneading with SPS and white smoke, gas burning, and roll adhesion during molding. If the kinematic viscosity exceeds 600 mm ² / s, burning of white smoke gas and the like is suppressed, but the effect of improving elongation is poor. These process oils can be used alone or in combination of two or more.

The above-mentioned various addition amounts are preferably 0 to 3% by mass, more preferably 0 to 3% by mass in the A layer, if necessary.
What is necessary is just to mix | blend in the range of 1.5 mass%.

The layer A of the present invention has the above composition, and the styrene polymer constituting the layer has a crystallinity of 20% or more, preferably 25% or more, more preferably 30% or more. Need to be. If the crystallinity is less than 20%, heat resistance and oil resistance may not be sufficient. The method for increasing the crystallinity of the styrene polymer constituting the layer A to 20% or more can be achieved, for example, by adjusting the stretching and heat treatment conditions in the method for producing a laminate described below. The crystallinity is the crystallinity of the syndiotactic polymer contained in the layer A, and can be measured by a differential scanning calorimeter.

The two A layers present on both sides of the B layer may have the same composition and properties, but may have different compositions and properties within the above range.

2. B Layer As the B layer of the present invention, a layer made of a styrene-based polymer having an atactic structure (hereinafter may be abbreviated as “PS”) or a resin composition containing the same is used. PS used in the present invention is industrially bulk polymerization,
It is a styrenic polymer obtained by radical polymerization by a method such as solution polymerization, suspension polymerization, or emulsion polymerization. Polystyrene obtained by such radical polymerization usually has an atactic structure and does not have stereoregularity. In addition, polystyrene having an atactic structure referred to herein is a polymer composed of one or more aromatic vinyl compounds or a copolymer of one or more other vinyl monomers copolymerizable with one or more aromatic vinyl compounds. It may be a polymer, a hydrogenated polymer of these polymers, or a mixture thereof.

Here, the aromatic vinyl compound includes styrene, α-methylstyrene, methylstyrene, ethylstyrene, isopropylstyrene, tertiary butylstyrene, phenylstyrene, vinylstyrene, chlorostyrene, bromostyrene, fluorostyrene, and chloromethylstyrene. , Methoxystyrene, ethoxystyrene and the like, and these are used alone or in combination of two or more. Among these, preferred aromatic vinyl compounds are styrene, p-methylstyrene, m-methylstyrene, ethylstyrene and p-tert-butylstyrene.

Other copolymerizable vinyl monomers include:
Acrylonitrile, vinylcyan compounds such as methachlornitrile, methyl acrylate, ethyl acrylate,
Propyl acrylate, butyl acrylate, amyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, dodecyl acrylate, octadecyl acrylate, phenyl acrylate, alkyl acrylates such as benzyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, Amyl methacrylate, hexyl methacrylate,
Octyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, phenyl methacrylate, alkyl methacrylates such as benzyl methacrylate, maleimide, N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N
And maleimide compounds such as -laurylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, and N- (p-bromophenyl) maleimide.

The molecular weight of this PS is not particularly limited, but generally, the one having a mass average molecular weight of 100,000 or more is used, preferably 150,000 to 500,000. Here, if the weight average molecular weight is less than 100,000, the mechanical properties of the obtained laminated film are undesirably reduced.

The layer B of the present invention is blended with the above-mentioned PS in addition to other thermoplastic resins, thermoplastic elastomers, compatibilizers, etc. and, if necessary, various additive lubricants within a range not to impair the purpose thereof. May be. These examples are:
The materials described for the layer A can be used.
The same applies to the mixing ratio.

However, except for other thermoplastic resins,
Atactic polystyrene, isotactic polystyrene, and HIPS exemplified in (1-1) are excluded, and instead, SPS not included in (1-1) is included.

The layer containing PS as a main component preferably contains 70% or more, more preferably 80%, and more preferably 90% or more of a styrene-based polymer component. If the amount of the styrene-based polymer component is small, the transparency after lamination deteriorates,
Insufficient adhesiveness with a layer containing as a main component may cause delamination during thermal processing.

3. Layer Structure of Laminated Film The laminated film of the present invention is composed of the A layer and the B layer. The ratio of the layer thickness of the A layer / B layer / A layer is 1/1.
8/1 to 1/2/2, furthermore 1/18/1 to 3/2 /
3, preferably 1/18/1 to 1/1/1. Here, if the layer A is too thin, problems tend to occur in the heat resistance and oil resistance of the laminated film, and if the layer A is relatively thick, problems tend to occur in the heat processability of the laminated film. The thickness of the A layer is 1 to 500 μm, and more preferably 1 to 400 μm.
m, particularly preferably 1 to 300 μm. If the A layer is less than 1 μm, problems tend to occur in the heat resistance and oil resistance of the laminated film,
If it is 500 μm or more, a problem is likely to occur in the thermal processability of the laminated film.

4. Total haze of laminated film The total haze of the laminated film composed of layer A / layer B / layer A of the present invention is a styrene-based laminated film having a total haze of 10% or less, preferably 8% or less, more preferably 6% or less. When the total haze exceeds 10%, the transparency and transparency of the film are insufficient, and the object of the present invention cannot be achieved. In order to reduce the total haze of the laminated film to 10 or less, the composition of each layer described above,
This can be achieved by appropriately adjusting the thickness ratio of each layer and the lamination conditions, stretching conditions, and heat treatment conditions.

5. Method for Producing Laminated Film The laminated film of the present invention can be produced by various methods conventionally used, and the polymer or resin composition for forming the layer A and the polymer or resin composition for forming the layer B are used together. By using a method of pressing and then co-stretching, efficient production can be achieved. The co-extrusion method is not particularly limited, but may be any of a feed block method and a multi-manifold method.
A die, a ring die, or the like can be used.

After the melt co-extrusion, after cooling and co-stretching, the crystallinity of the layer A is improved and transparency is exhibited. As a method of co-stretching, for example, uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, and a multi-stage stretching method combining these can be used. Among them, in the present invention, it is preferable to use a simultaneous or sequential biaxial stretching method. In this case, the area stretching ratio is preferably 3 to 20 times,
5 to 10 times is more preferable. The co-stretching temperature is 90 to
200 ° C is preferable, and 90 to 150 ° C is more preferable.
After the co-stretching, a heat treatment is preferably performed. Under tension, the heat treatment is preferably performed at 100 to 270 ° C, more preferably 150 to 270 ° C, preferably 1 to 300 seconds, more preferably 1 to 60 seconds. By the above method, a laminated film having excellent interlayer adhesion and higher transparency can be produced without using an adhesive.

The preferred method for producing the laminated film of the present invention is as described above. The polymer or resin composition for forming the layer A and the polymer or resin composition for forming the layer B at 290 ° C. and a shear rate of 10 ^-1. The melt viscosity ratio (melt viscosity of layer A) / (melt viscosity of layer B) at sec ^-1 is preferably from 0.3 to 3, and more preferably from 0.5 to 2. When the ratio of the melt viscosities of both is less than 0.3 or more than 3, the interface of each layer after co-extrusion becomes coarse, and it may be difficult to obtain a desired transparent laminate. In addition, as a method other than the above-mentioned method, a single film may be prepared and laminated using an adhesive.

6. Use of the laminated film The use of the laminated film of the present invention is not particularly limited and can be widely used, but since it has the above-mentioned properties, food, medicine, stationery, packaging films and bags and containers for daily necessities, release films. It is particularly useful for industrial films and containers such as adhesive tapes and capacitor derivatives.

[0051]

EXAMPLES Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. [Method for Measuring Physical Properties of Film] Ratio of Layer Thickness to Layer Thickness A polarizing microscope photograph was taken of a cross section of the film, and the thickness of each layer was measured. The ratio of the layer thickness was calculated from the thickness of each layer. Crystallinity The laminated film was calculated by the following equation using the enthalpy of fusion (ΔHf) and the enthalpy of cold crystallization (ΔH _Tcc ) measured at a heating rate of 20 ° C./min with a differential scanning calorimeter. Crystallinity (%) = 100 × (ΔHf−ΔH _Tcc ) / (5
3 (J / g) × SPS content ratio in layer) Total haze Measured according to JIS K 7105 method. Tensile modulus, breaking strength Measured according to JIS Z 1702. Film Impact Toyo Seiki Film Impact Tester (Pendulum type)
And measured with a 1/2 inch (1.27 cm) impact head. Surface layer heat resistance Using a film piece, a heat seal test was performed in accordance with JIS Z 1707, and the surface layer (SPS / PS laminate was S
On the PS side), the maximum temperature at which there was no change in appearance was measured. Oil resistance MC on the film surface (SPS / PS laminate for SPS side)
T oil was applied, and the change after 30 minutes at 80 ° C. was measured. The measurement results were displayed according to the following criteria. : Haze value less than 10%, ×: Dissolution or haze value: 10% or more Thermoformability (suitability for thermal processing) Using a thermoforming machine manufactured by Asano Seisakusho, sheet heating temperature 150
Plug-assist vacuum air pressure molding was performed at 200 ° C. and a mold temperature of 60 ° C., and the mold reproducibility of a crane-shaped container (drawing ratio 0.2, expansion ratio 1.5 times) was evaluated. ：: Good container appearance and shape can be formed. ×: Any failure such as breakage, warpage or delamination (delamination) occurs during molding.

[SPS, Compounding Agents and Additives Used Other than in Production Examples] A styrene polymer having a syndiotactic structure (SPS)
-3) SPS having a mass average molecular weight of 400,000 and syndiotacticity (racemic pendat) of 97% Styrene polymer having an atactic structure (PS-1) HH32 (GPPS) manufactured by Idemitsu Petrochemical Co., Ltd. Styrene having an atactic structure -Based polymer (PS-2) HH30 (GPPS) manufactured by Idemitsu Petrochemical Co., Ltd.-Polyethylene terephthalate (PET) Diamondite MA523 manufactured by Mitsubishi Rayon-Polyphenylene sulfide (PPS) Intrinsic viscosity [η] = 0.28 dl / g-Bisphenol A type polycarbonate (PC) Idemitsu Petrochemical Idemitsu Polycarbonate A300 ・ Lubricant-1 Aluminosilicate (manufactured by Mizusawa Chemical, Shilton AMT0)
8) Antioxidant-1 pentaerythrityl-tetrakis [3- (3,5-di-
t-butyl-4-hydroxyphenyl) propionate], IRGANOX 1010 (manufactured by Ciba Specialty Chemical Co.)

[Preparation of polymerization catalyst] Toluene, 3.8 mmol of triisobutylaluminum, 16.8 mmol of methylaluminoxane were placed in a vessel which had been sufficiently dried and purged with nitrogen.
l, 0.15 mmol of octahydrofluorenyltitanium trimethoxide was added and adjusted to a Ti concentration of 3 mmol / l. Each component was stirred for 1 hour after mixing, and used as a catalyst.

[Production Example 1: Production of styrene-p-methylstyrene copolymer (SPS-1)] In a reactor which has been sufficiently dried and purged with nitrogen, 4.7k of styrene is placed.
g, 0.3 kg of paramethylstyrene, triethylaluminum was converted to styrene / triethylaluminum = 350,
000/100 and stirred well. After heating the mixture of styrene, paramethylstyrene and triethylaluminum to 73 ° C., 21 ml of the catalyst prepared above was added to the mixture to initiate polymerization. One hour later, methanol was added to terminate the polymerization. The obtained polymer was washed with methanol and dried at 200 ° C. for 2 hours. The yield was 1210 g and the weight average molecular weight was 263,000. Paramethylstyrene content in the obtained polymer is ¹
It was 5.9 mol% as measured using 1 H NMR.

[Production Example 2: Styrene homopolymer (SP
Production of S-2) 5 kg of styrene is placed in a reactor which is sufficiently dried and purged with nitrogen.
Triethylaluminum was added so that styrene / triethylaluminum = 350,000 / 100, and the mixture was sufficiently stirred. After heating the mixture of styrene and triethylaluminum to 80 ° C., 21 ml of the catalyst prepared above was added to the mixture to initiate polymerization. One hour later, methanol was added to terminate the polymerization. The obtained polymer was washed with methanol and dried at 200 ° C. for 2 hours. The yield was 1,230 g, and the mass average molecular weight was 207,000.

Example 1 SPS-1 obtained in Production Example 1
Lubricant-1 at 1,000 ppm, antioxidant-1 at 3,
000 ppm, and melt-extruded at 300 ° C. to obtain pellets. 300 ° C., shear rate 10 ⁻¹ sec
The melt viscosity of ^-1 was 1,000 Pa · S. Further, PS-1 (29) is used as a styrenic polymer having an atactic structure.
The melt viscosity at 0 ° C. and a shear rate of 10 ⁻¹ sec ⁻¹ is 500 Pa
・ S) was prepared. 30m each of these two materials
300 ℃ with mΦ single screw extruder, 2 with 40mmΦ single screw extruder
The sheet was extruded at 60 ° C., co-extruded through a feed block set at 300 ° C. and a coat hanger die, and cooled with a cooling roll at 85 ° C. to obtain a three-layer unstretched sheet of A layer / B layer / A layer. The unstretched three-layer sheet is continuously stretched in the longitudinal direction for 1
The film was stretched 3.4 times at 05 ° C., then 3.8 times at 115 ° C. in the transverse direction, and then subjected to a heat treatment at 200 ° C. for 10 seconds while relaxing 5% in the width direction. Physical properties of the obtained three-layer stretched film were measured, and the results are shown in Table 1. However, in Table 1, the blending of the additives is omitted.

Example 2 A laminated film was prepared in the same manner as in Example 1 except that the extrusion amount was adjusted and the thickness of each layer was changed. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. [Example 3] A three-layer stretched film was obtained in the same manner as in Example 1 except that the extrusion rate and the take-up speed of the unstretched sheet were adjusted, the thickness of each layer was changed, and no heat treatment was performed. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. Example 4 SPS-2 (290) obtained in Production Example 2
° C, melt viscosity 600 Pa · at a shear rate of 10 ^-1 sec ^-1
S) and P as an atactic styrene polymer
Using S-2 (290 ° C., melt viscosity of 300 Pa · S at a shear rate of 10 ⁻¹ sec ⁻¹ ), adjusting the extrusion rate and changing the thickness of each layer, a three-layer stretched film was obtained in the same manner as in Example 1. I got The physical properties of the obtained laminated film were measured, and the results are shown in Table 1.

COMPARATIVE EXAMPLE 1 Extruded in the same manner as in Example 1 except that SPS-1 was not used, to produce a 12-μm-thick stretched film of PS-1 single layer (only layer B). The physical properties of the obtained film were measured, and the results are shown in Table 1.
It was shown to. [Comparative Example 2] A 12 µm-thick stretched film of a single layer of syndiotactic styrene polymer (only layer A) was prepared in the same manner as in Example 1 except that PS-1 was not used. The physical properties of the obtained film were measured, and the results are shown in Table 1.
It was shown to. [Comparative Example 3] A 200 µm-thick stretched film of a single layer of syndiotactic styrene polymer (only layer A) was prepared in the same manner as in Example 3 except that PS-1 was not used. The physical properties of the obtained film were measured, and the results are shown in Table 1.

[Comparative Example 4] The extrusion rate and the take-off speed of the unstretched sheet were adjusted to change the thickness of each layer,
A three-layer unstretched film of layer A / layer B / layer A was prepared in the same manner as in Example 1 except that the heat treatment was not performed. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. [Comparative Example 5] A three-layer stretched film was prepared in the same manner as in Example 1 except that a two-layer structure of layer A / layer B of SPS-1 / PS-1 was used. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. [Comparative Example 6] Using the stretched film of PS-1 obtained in Comparative Example 1 and the stretched film of SPS-1 obtained in Comparative Example 2, an acrylic dry laminating adhesive Umenbond BS-2 was used.
00 (manufactured by Okura Industry Co., Ltd.) to form a laminated film of layer A / layer B / layer A. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. The total haze of this film was high at 13%.

[Comparative Example 7] SPS-3 and PET were co-extruded with a cast molding machine having a multilayer die (T die temperature: 300 ° C, take-up speed: 1 m / sec), and cooled by a cold roll to form SPS-3. / PET / SPS-3 three-layer film was obtained. This film was stretched 3 × 3 times (temperature 115 ° C.) with a table tenter to obtain a film. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. Comparative Example 8 A film was prepared in the same manner as in Comparative Example 7 except that PPS was used instead of PET and the T-die temperature was set at 320 ° C., and stretched 3 × 3 times (at a temperature of 96 ° C.) to obtain A layer film was obtained. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1. The total haze of this film was high, 15%. Comparative Example 9 A biaxially stretched film, an SPS-3 film, and a PC film were laminated with a curable urethane-based adhesive to obtain a three-layer film of SPS-3 / PC / SPS-3. The physical properties of the obtained laminated film were measured, and the results are shown in Table 1.

[0061]

[Table 1]

[0062]

The laminated film of the present invention has excellent heat resistance, oil resistance, and mechanical strength, and also has excellent heat processing suitability (thermoformability) and transparency.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AK12A AK12B AK12C AL05A AL05B AL05C BA03 BA06 BA10B BA10C BA21 EH202 EJ373 GB15 JA06A JA06B JA06C JA11A JA12B JA12C JB07 JJ03 JK01 JL01 JN01 YY00YYC00

Claims (4)

[Claims] 1. A laminated film comprising the following layer A laminated on both sides of layer B, wherein the total haze of the laminated film is 10%
The following polystyrene-based laminated film. A layer: a layer composed of a styrene polymer having a syndiotactic structure or a resin composition containing the same, wherein the styrene polymer has a crystallinity of 20% or more. B layer: a layer composed of a styrene-based polymer having an atactic structure or a resin composition containing the same. 2. The polystyrene-based laminated film according to claim 1, wherein the ratio of the thickness of each of the layer A / layer B / layer A is 1/18/1 to 2/1/2. 3. The polystyrene-based laminated film according to claim 1, wherein no adhesive is present between any of the A layer and the B layer. 4. A polymer or resin composition for forming the layer A and a polymer or resin composition for forming the layer B at 290.degree.
The melt viscosity ratio at ^-1 sec ^-1 is 0.3 to 3, and after melt coextrusion using the polymer or the composition, stretching is performed. A method for producing a polystyrene-based laminated film.