STRETCHED MULTILAYER THERMOPLASTIC RESIN FILM

Abstract

The present invention is able to provide a stretched multilayer thermoplastic resin film which comprises layers containing a thermoplastic resin (B) on both surfaces of a layer that contains a thermoplastic resin (A) and elastic particles, and wherein: respective intrinsic birefringences of the thermoplastic resin (A) and the thermoplastic resin (B) are within the range of from 0.005 to 0.005; the content ratio of the elastic particles in the whole layer containing the thermoplastic resin (A) and the elastic particles is 5-40% by weight; the glass transition temperature of the thermoplastic resin (B) is 110 C. or higher and the saturation water absorption of the thermoplastic resin (B) is less than 1.1 wt %.

Claims

1. A stretched multilayer thermoplastic resin film which comprises layers containing a thermoplastic resin (B) on both surfaces of a layer that contains a thermoplastic resin (A) and elastic particles, wherein: respective intrinsic birefringences of the thermoplastic resin (A) and the thermoplastic resin (B) are within the range of from 0.005 to 0.005; a content ratio of the elastic particles in the whole layer containing the thermoplastic resin (A) and the elastic particles is 5 to 40% by weight; a glass transition temperature of the thermoplastic resin (B) is 110 C. or higher; and a saturated water absorption rate of the thermoplastic resin (B) is less than 1.1 wt %.

2. The stretched multilayer thermoplastic resin film according to claim 1, which has an in-plane retardation Re of 0.0 to 3.0 nm and a thickness direction retardation Rth of 10.0 to 10.0 nm at a wavelength of 590 nm.

3. The stretched multilayer thermoplastic resin film according to claim 1, wherein the thermoplastic resin (B) comprises a (meth)acrylic acid ester structural unit (a) represented by general formula (1) below: ##STR00005## (wherein R1 represents a hydrogen atom or a methyl group, and R2 represents a C.sub.1-C.sub.16 hydrocarbon group), and an aliphatic vinyl structural unit (b) represented by general formula (2) below: ##STR00006## (wherein R3 represents a hydrogen atom or a methyl group, and R4 represents a cyclohexyl group or a cyclohexyl group having a C.sub.1-C.sub.4 hydrocarbon substituent), and wherein a ratio of the sum of the (meth)acrylic acid ester structural unit (a) and the aliphatic vinyl structural unit (b) is 90 to 100 mol % relative to the sum of all the structural units in the thermoplastic resin (B), and wherein a molar ratio between the (meth)acrylic acid ester structural unit (a) and the aliphatic vinyl structural unit (b) is 55:45 to 85:15.

4. The stretched multilayer thermoplastic resin film according to claim 3, wherein each of R1 and R2 in general formula (1) is a methyl group.

5. The stretched multilayer thermoplastic resin film according to claim 3, wherein R4 in general formula (2) is a cyclohexyl group.

6. The stretched multilayer thermoplastic resin film according to claim 1, wherein the elastic particles comprise a methyl methacrylate structural unit and an acrylic acid alkyl ester structural unit.

7. The stretched multilayer thermoplastic resin film according to claim 1, wherein the stretched is biaxially stretched.

8. The stretched multilayer thermoplastic resin film according to claim 1, wherein a magnification of stretching in at least one stretching direction is 1.1 to 3.0 times.

9. The stretched multilayer thermoplastic resin film according to claim 1, which has a total thickness of 10 to 1000 m.

10. The stretched multilayer thermoplastic resin film according to claim 1, wherein a ratio of the thickness of the layers containing the thermoplastic resin (B) (the sum of the two layers on both the surfaces of the (A) layer) to the total thickness of the layer containing the thermoplastic resin (A) and the layers containing the thermoplastic resin (B)(the sum of the three layers which are the (B) layer/the (A) layer/the (B) layer) is 5 to 70%.

11. The stretched multilayer thermoplastic resin film according to claim 1, wherein the layer containing the thermoplastic resin (A) comprises at least one selected from the group consisting of an ultraviolet absorber, an antioxidant, an anti-coloring agent, an antistatic agent, a mold release agent, a lubricant, a dye and a pigment.

12. An optical film comprising the stretched multilayer thermoplastic resin film according to claim 1.

13. A polarizer protective film comprising the optical film according to claim 12.

14. A polarizing plate comprising the polarizer protective film according to claim 13 and a polarizer.

15. A method for producing the stretched multilayer thermoplastic resin film according to claim 1, which comprises stretching at a stretching temperature that is equal to or higher than a glass transition temperature TgB ( C.) of the thermoplastic resin (B).

Description

EXAMPLES

[0055] Hereinafter, the present invention will be described in detail by way of the Examples, but the present invention is not limited by the Examples and Comparative Examples. The stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples were evaluated as described below.

<Hydrogenation Reaction Rate of Copolymer>

[0056] Regarding the thermoplastic resins obtained in Synthesis Examples described below, the hydrogenation reaction rate was obtained based on the decrease ratio of absorption at 260 nm in the UV spectrum measurement before and after hydrogenation reaction. Using the absorbance A1 in the case of the concentration C1 of resin before hydrogenation reaction and the absorbance A2 in the case of the concentration C2 of resin after hydrogenation reaction, calculation was carried out according to the below-described formula.

Hydrogenation reaction rate (%)=100[1(A2C1)/(A1C2)]

<Intrinsic Birefringence Value>

[0057] Regarding the thermoplastic resins obtained in Synthesis Examples described below, the difference in dielectric polarization of bonding units of respective structural units was calculated according to the molecular orbital method, and as a volume average value thereof, an intrinsic birefringence value was calculated according to the below-described Lorentz-Lorenz equation.

n.sub.0=2/9(n.sup.2+2).sup.2/nP.Math.d.Math.N/M

(n.sub.0: intrinsic birefringence value, P: difference between dielectric polarization in the direction of molecular chain axis and dielectric polarization in the direction perpendicular to the molecular chain axis, n: refractive index, d: density, N: Avogadro's number, M: molecular weight)

<Evaluation of Continuous Productivity>

[0058] In the preparation of the raw material films of the Examples and Comparative Examples described below, molding was continuously performed for 6 hours, and after that, the surfaces of mirror surface rolls were visually observed. The case where contamination derived from bleeding out of an additive was not caused on the surfaces of the mirror surface rolls was regarded as passed (o), and the other cases were regarded as failed (x).

<Thickness>

[0059] The stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below were measured using a digital micrometer (manufactured by Sony Magnescale Co., Ltd., M-30). The average of 10 measurement points of the obtained stretched multilayer thermoplastic resin film was regarded as the thickness of the film.

<Evaluation of Adhesion>

[0060] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, a test piece with a size of 100 mm300 mm was obtained by cutting, the test piece was pressed to a cylinder having a diameter of 80 mm so that the long side was in the circumferential direction, and the presence or absence of detachment of the interface between laminated resins was evaluated. The case where detachment was caused in 2 or less out of 10 pieces was regarded as passed (o), and the other cases were regarded as failed (x).

<Evaluation of Transparency>

[0061] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, the haze was measured using a colorimeter COH-400 manufactured by Nippon Denshoku Industries Co., Ltd. in accordance with JIS K 7105 and ASTM D1003. The case where the haze was 1.0% or less was regarded as passed (), and the other cases were regarded as failed (x).

<Evaluation of Optical Isotropy>

[0062] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, a slow phase axis was detected at a measurement wavelength of 590 nm using a spectroscopic ellipsometer (manufactured by JASCO Corporation, M-220), and in-plane principal refractive indices, nx and ny (with the proviso that nx>ny) and a principal refractive index in the thickness direction nz, at a wavelength of 590 nm, were measured with the three-dimensional refractive index measurement mode (tilt angle: 8 to 8). The in-plane retardation Re and the thickness direction retardation Rth were calculated according to the below-described formula. The case where the in-plane retardation Re was within the range of 0.0 to 3.0 nm was regarded as passed (), and the other cases were regarded as failed (x). Further, the case where the thickness direction retardation Rth was within the range of 10.0 to 10.0 nm was regarded as passed (o), and the other cases were regarded as failed (x).

Re=(nxny)d (d: film thickness)

Rth=((nx+ny)/2nz)d

<Evaluation of Mechanical Strength (Folding Resistance)>

[0063] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, the number of times of folding until a fracture was generated was measured with a folding angle of 135 to the left and right from the center, a load of 500 g and a rate of 180 times/min using an MIT type folding endurance tester (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS P 8115. The case where the number of times of folding until a fracture was generated was 100 times or more was regarded as passed (), and the other cases were regarded as failed (x).

<Evaluation of Punching Properties>

[0064] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, each film was pressed and cut at a cutting speed of 145 spm using Super Cutter PJ1-0600 (razor blade) manufactured by Ogino Seiki Co., Ltd. After that, the pressed/cut surface of the film was observed from the direction of blade insertion using a digital microscope MXG-2500REZ (magnification 100) manufactured by HIROX Co., Ltd. The case where the size of a crack and delamination generated in the cut surface was 10 m or less was regarded as passed (), and the other cases were regarded as failed (x).

<Evaluation of Dimensional Stability>

[0065] Regarding the stretched multilayer thermoplastic resin films obtained in the Examples and Comparative Examples described below, a test piece which was left at 23 C. and at a relative humidity of 50% for 24 hours or longer was cut into a size of 120 mm120 mm. A reference line (100 mm) was drawn in the extrusion direction (MD) and the direction perpendicular to the extrusion direction (TD) of the test piece, and the average value of the lengths of the reference lines drawn in the MD direction and the TD direction was regarded as the initial size. The test piece was held at 85 C. and at a humidity of 85% RH for 48 hours. The lengths of the reference lines drawn in the MD direction and the TD direction of the test piece taken out were measured again, and the average value thereof was regarded as the size after the test. The dimensional change rate was calculated using the below-described formula. The case where dimensional change at 85 C. and 85% RH was 0.0 to 5.0% (shrank) was regarded as passed (o), and the other cases were regarded as failed (x).

Dimensional change rate (%)=((size after testinitial size)/initial size)100

Synthesis Example 1 [Production of Vinyl Copolymer Resin (B1)]

[0066] A monomer composition consisting of 77.0 mol % of purified methyl methacrylate (manufactured by Mitsubishi Gas Chemical Company, Inc.), 23.0 mol % of purified styrene (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.002 mol % of t-amyl peroxy-2-ethylhexanoate (manufactured by Arkema Yoshitomi, Ltd., trade name: Luperox 575) as a polymerization initiator was continuously fed to a 10-L complete mixing bath equipped with a helical ribbon impeller at a feed rate of 1 kg/h, and the monomer composition was continuously polymerized at a polymerization temperature of 150 C. for an average retention time of 2.5 hours. The reaction mixture was continuously removed through the bottom of the polymerization bath so that the liquid surface in the bath became constant, and it was introduced into a solvent-removing apparatus, thereby obtaining a vinyl copolymer resin (B) in a pellet form.

[0067] The obtained vinyl copolymer resin (B1) was dissolved in methyl isobutylate (manufactured by Kanto Chemical Co., Inc.), thereby preparing a 10 wt % solution of methyl isobutylate. To a 1000-mL autoclave, 500 parts by weight of the 10 wt % solution of methyl isobutylate containing (B) and 1 part by weight of 10 wt % Pd/C (manufactured by N.E. Chemcat Corporation) were fed, and the mixture was maintained under a hydrogen pressure of 9 MPa at 200 C. for 15 hours, thereby hydrogenating a benzene ring moiety. The catalyst was removed using a filter, and the filtrate was introduced into a solvent-removing apparatus, thereby obtaining a vinyl copolymer resin (B1) in a pellet form. According to the .sup.1H-NMR measurement, the ratio of the methyl methacrylate structural unit was 75 mol %, and according to the measurement of absorbance at a wavelength of 260 nm, the hydrogenation reaction rate of the benzene ring moiety was 99%. The glass transition temperature of the obtained vinyl copolymer resin (B1) was 120 C., and the saturated water absorption rate was 0.9 wt %. Further, the intrinsic birefringence of the obtained vinyl copolymer resin (B1) was 0.0003.

Synthesis Example 2 [Production of Vinyl Copolymer Resin (B2)]

[0068] A vinyl copolymer resin (B2) was obtained in a manner similar to that in Synthesis Example 1, except that the amount of the methyl methacrylate used in Synthesis Example 1 was changed to 62.0 mol % and the amount of the styrene was changed to 38.0 mol %. According to the .sup.1H-NMR measurement, the ratio of the methyl methacrylate structural unit was 60 mol %, and according to the measurement of absorbance at a wavelength of 260 nm, the hydrogenation reaction rate of the benzene ring moiety was 99%. The glass transition temperature of the obtained vinyl copolymer resin (B2) was 120 C., and the saturated water absorption rate was 0.6 wt %. Further, the intrinsic birefringence of the obtained vinyl copolymer resin (B2) was +0.0021.

Synthesis Example 3 [Production of Vinyl Copolymer Resin (B3)]

[0069] A vinyl copolymer resin (B3) was obtained in a manner similar to that in Synthesis Example 1, except that the amount of the methyl methacrylate used in Synthesis Example 1 was changed to 32.0 mol % and the amount of the styrene was changed to 68.0 mol %. According to the .sup.1H-NMR measurement, the ratio of the methyl methacrylate structural unit was 30 mol %, and according to the measurement of absorbance at a wavelength of 260 nm, the hydrogenation reaction rate of the benzene ring moiety was 99%. The glass transition temperature of the obtained vinyl copolymer resin (B3) was 123 C., and the saturated water absorption rate was 0.4 wt %. Further, the intrinsic birefringence of the obtained vinyl copolymer resin (B3) was +0.0069.

Synthesis Example 4 [Production of Vinyl Copolymer Resin (B4)]

[0070] A vinyl copolymer resin (B4) was obtained in a manner similar to that in Synthesis Example 1, except that the amount of the methyl methacrylate used in Synthesis Example 1 was changed to 92.0 mol % and the amount of the styrene was changed to 8.0 mol %. According to the .sup.1H-NMR measurement, the ratio of the methyl methacrylate structural unit was 90 mol %, and according to the measurement of absorbance at a wavelength of 260 nm, the hydrogenation reaction rate of the benzene ring moiety was 99%. The glass transition temperature of the obtained vinyl copolymer resin (B4) was 112 C., and the saturated water absorption rate was 1.3 wt %. Further, the intrinsic birefringence of the obtained vinyl copolymer resin (B4) was 0.0027.

Synthesis Example 5 [Production of Vinyl Copolymer Resin (B5)]

[0071] A vinyl copolymer resin (B5) was obtained in a manner similar to that in Synthesis Example 1, except that the reaction time for hydrogenation of the benzene ring moiety was changed to 5 hours. According to the .sup.1H-NMR measurement, the ratio of the methyl methacrylate structural unit was 75 mol %, and according to the measurement of absorbance at a wavelength of 260 nm, the hydrogenation reaction rate of the benzene ring moiety was 82%. The glass transition temperature of the obtained vinyl copolymer resin (B5) was 116 C., and the saturated water absorption rate was 0.9 wt %. Further, the intrinsic birefringence of the obtained vinyl copolymer resin (B5) was 0.0055.

Synthesis Example 6 [Production of Elastic Particles]

[0072] 300 parts by weight of ion-exchanged water, 1.0 part by weight of sodium stearate and 0.08 part by weight of N-sodium lauroyl sarcosinate were put into a reaction container equipped with a reflux cooling apparatus, the mixture was heated to 70 C. under nitrogen atmosphere while stirring, and a monomer mixture consisting of 50 parts by weight of methyl methacrylate, 2 parts by weight of methyl acrylate and 0.15 part by weight of allyl methacrylate was added thereto. Subsequently, 0.6 part by weight of 10% aqueous solution of potassium persulfate was added thereto, and the mixture was heated to 80 C. and held for 60 minutes.

[0073] Subsequently, 0.3 part by weight of 10% aqueous solution of potassium persulfate was added thereto in the presence of the latex, and a monomer mixture consisting of 28.0 parts by weight of butyl acrylate, 5.8 parts by weight of styrene and 0.8 part by weight of allyl methacrylate was continuously added thereto over 60 minutes. After the addition was completed, the mixture was held for 30 minutes.

[0074] Subsequently, 0.3 part by weight of 10% aqueous solution of potassium persulfate was added thereto in the presence of the latex, and a monomer mixture consisting of 29 parts by weight of methyl methacrylate, 1 part by weight of methyl acrylate and 0.06 part by weight of n-octyl mercaptan was continuously added thereto over 30 minutes. After the addition was completed, the mixture was held for 60 minutes, thereby obtaining a three-layer structured polymer latex.

[0075] The latexes obtained by sampling during polymerization and at the time of the completion of polymerization were observed using a scanning electron microscope to obtain the average particle diameter, and it was 0.17 m when including only the innermost layer, 0.20 m when including the innermost layer and the intermediate layer, and 0.21 m when including the innermost layer, the intermediate layer and the outermost layer.

[0076] The latexes thus obtained were put into a stainless steel container, frozen, and melted at 70 C. After that, the polymer was separated by filtration. In addition, it was subjected to washing with hot water at 70 C. and dehydration three times and then dried at 80 C. for 10 hours, thereby obtaining multilayer elastic particles.

Production Example 1 [Production of Thermoplastic Resin Composition (A1)]

[0077] 95 parts by weight of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)), 5 parts by weight of elastic particles obtained in Synthesis Example 6 and 1.2 parts by weight of a triazine-based ultraviolet absorber (ADK STAB LA-F70 manufactured by ADEKA Corporation) were continuously introduced into a twin screw extruder having a screw diameter of 30 mm and extruded at a cylinder temperature of 250 C. and a discharge rate of 25 kg/hour, thereby obtaining a thermoplastic resin composition (A1) in which the ultraviolet absorber was added to methyl methacrylate.

Production Example 2 [Production of Thermoplastic Resin Composition (A2)]

[0078] A thermoplastic resin composition (A2) was obtained in a manner similar to that in Production Example 1, except that the amount of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) of Production Example 1 was changed to 80 parts by weight, and that the amount of the elastic particles obtained in Synthesis Example 6 was changed to 20 parts by weight.

Production Example 3 [Production of Thermoplastic Resin Composition (A3)]

[0079] A thermoplastic resin composition (A3) was obtained in a manner similar to that in Production Example 1, except that the amount of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) of Production Example 1 was changed to 60 parts by weight, and that the amount of the elastic particles obtained in Synthesis Example 6 was changed to 40 parts by weight.

Production Example 4 [Production of Thermoplastic Resin Composition (A4)]

[0080] A thermoplastic resin composition (A4) was obtained in a manner similar to that in Production Example 1, except that the amount of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) of Production Example 1 was changed to 100 parts by weight, and that the amount of the elastic particles obtained in Synthesis Example 6 was changed to 0 part by weight.

Production Example 5 [Production of Thermoplastic Resin Composition (A5)]

[0081] A thermoplastic resin composition (A) was obtained in a manner similar to that in Production Example 1, except that the amount of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) of Production Example 1 was changed to 50 parts by weight, and that the amount of the elastic particles obtained in Synthesis Example 6 was changed to 50 part by weight.

Production Example 6 [Production of Vinyl Copolymer Resin Composition (B6)]

[0082] A vinyl copolymer resin composition (B6) was obtained in a manner similar to that in Production Example 4, except that the vinyl copolymer resin (B1) obtained in Synthesis Example 1 was introduced instead of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) used in Production Example 4.

Production Example 7 [Production of Vinyl Copolymer Resin Composition (B7)]

[0083] A vinyl copolymer resin composition (B7) was obtained in a manner similar to that in Production Example 4, except that the vinyl copolymer resin (B2) obtained in Synthesis Example 2 was introduced instead of methyl methacrylate (SUMIPEX MG5 manufactured by Sumitomo Chemical Co., Ltd. (intrinsic birefringence: 0.0043, glass transition temperature: 105 C.)) used in Production Example 4.

Example 1 [Resin (B1)/Resin (A1)/Resin (B1), Layer Ratio 1:3:1]

[0084] A laminate was molded using a multilayer extruder having a single screw extruder with a screw diameter of 32 mm, a single screw extruder with a screw diameter of 65 mm, a feed block connected to all the extruders and a T-die connected to the feed block. The vinyl copolymer resin (B1) obtained in Synthesis Example 1 was continuously introduced into the single screw extruder with the screw diameter of 32 mm and extruded at a cylinder temperature of 250 C. and a discharge rate of 20.0 kg/hour. Further, the thermoplastic resin composition (A1) obtained in Production Example 1 was continuously introduced into the single screw extruder with the screw diameter of 65 mm and extruded at a cylinder temperature of 250 C. and a discharge rate of 30.0 kg/hour. The feed block connected to all the extruders had a distribution pin for two types of three layers, and the thermoplastic resin composition (A1) and the vinyl copolymer resin (B1) were introduced into it at 250 C. to perform lamination. The laminated product was extruded into a sheet shape with the T-die connected to the feed block at 250 C., and it was cooled using 3 mirror surface rolls each at 110 C., 95 C. and 90 C. from the upstream side, thereby obtaining a raw film in which the vinyl copolymer resin (B1) was laminated on both the surfaces of the thermoplastic resin composition (A1). The thickness of the obtained raw film was 140 m. The obtained raw film was biaxially stretched using a fixed end simultaneous biaxial stretching machine. The stretching temperature was set at 160 C., the preheating time was sufficiently provided, the stretching rate was 300 mm/min, the stretching magnifications were 1.85 times (vertical) and 1.85 times (horizontal), and thus a stretched multilayer thermoplastic resin film was prepared. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B1)/(A)/(B1)=8 m/24 m/8 sm. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength, punching properties and dimensional stability were all good, and the synthetic judgement was passed (o).

Example 2 [Resin (B1)/Resin (A2)/Resin (B1), Layer Ratio 1:3:1]

[0085] The vinyl copolymer resin (B) was laminated on both the surfaces of the thermoplastic resin composition (A2) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 1, except that the thermoplastic resin composition (A2) obtained in Production Example 2 was introduced instead of the thermoplastic resin composition (A1) used in Example 1. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B1)/(A2)/(B1)=8 m/24 s/8 m. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength, punching properties and dimensional stability were all good, and the synthetic judgement was passed (o).

Example 3 [Resin (B1)/Resin (A3)/Resin (B1), Layer Ratio 1:3:1]

[0086] The vinyl copolymer resin (B) was laminated on both the surfaces of the thermoplastic resin composition (A3) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 1, except that the thermoplastic resin composition (A3) obtained in Production Example 3 was introduced instead of the thermoplastic resin composition (A1) used in Example 1. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B1)/(A3)/(B1)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength, punching properties and dimensional stability were all good, and the synthetic judgement was passed (o).

Example 4 [Resin (B2)/Resin (A2)/Resin (B2), Layer Ratio 1:3:1]

[0087] The vinyl copolymer resin (B2) was laminated on both the surfaces of the thermoplastic resin composition (A2) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 2, except that the vinyl copolymer resin (B2) obtained in Synthesis Example 2 was introduced instead of the vinyl copolymer resin (B1) used in Example 2. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B2)/(A2)/(B2)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength, punching properties and dimensional stability were all good, and the synthetic judgement was passed (o).

Comparative Example 1 [Resin (B1)/Resin (A4)/Resin (B1), Layer Ratio 1:3:1]

[0088] The vinyl copolymer resin (B1) was laminated on both the surfaces of the thermoplastic resin composition (A4) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 1, except that the thermoplastic resin composition (A4) obtained in Production Example 4 was introduced instead of the thermoplastic resin composition (A1) used in Example 1. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B1)/(A4)/(B1)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength and dimensional stability were all good, but the evaluation result regarding punching properties was poor. The synthetic judgement was failed (x).

Comparative Example 2 [Resin (B1)/Resin (A5)/Resin (B1), Layer Ratio 1:3:1]

[0089] The vinyl copolymer resin (B1) was laminated on both the surfaces of the thermoplastic resin composition (A5) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 1, except that the thermoplastic resin composition (A5) obtained in Production Example 5 was introduced instead of the thermoplastic resin composition (A1) used in Example 1. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B1)/(A5)/(B1)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, adhesion, mechanical strength and punching properties were good, but the evaluation results regarding transparency, optical isotropy and dimensional stability were poor. The synthetic judgement was failed (x).

Comparative Example 3 [Resin (B3)/Resin (A2)/Resin (B3), Layer Ratio 1:3:1]

[0090] The vinyl copolymer resin (B3) was laminated on both the surfaces of the thermoplastic resin composition (A2) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 2, except that the vinyl copolymer resin (B3) obtained in Synthesis Example 3 was introduced instead of the vinyl copolymer resin (B1) used in Example 2. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B3)/(A2)/(B3)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, transparency, optical isotropy, mechanical strength and dimensional stability were good, but the evaluation results regarding adhesion and punching properties were poor. The synthetic judgement was failed (x).

Comparative Example 4 [Resin (B4)/Resin (A2)/Resin (B4), Layer Ratio 1:3:1]

[0091] The vinyl copolymer resin (B4) was laminated on both the surfaces of the thermoplastic resin composition (A2) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 2, except that the vinyl copolymer resin (B4) obtained in Synthesis Example 4 was introduced instead of the vinyl copolymer resin (B1) used in Example 2. Roll contamination did not occur at the time of continuous molding of the raw film. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B4)/(A2)/(B4)=8 m/24 m/8 sm. The evaluation results regarding continuous productivity, adhesion, transparency, optical isotropy, mechanical strength and punching properties were good, but the evaluation result regarding dimensional stability was poor. The synthetic judgement was failed (x).

Comparative Example 5 [Resin (B5)/Resin (A2)/Resin (B5), Layer Ratio 1:3:1]

[0092] The vinyl copolymer resin (B5) was laminated on both the surfaces of the thermoplastic resin composition (A2) and the obtained product was stretched, thereby obtaining a stretched multilayer thermoplastic resin film in a manner similar to that in Example 2, except that the vinyl copolymer resin (B5) obtained in Synthesis Example 5 was introduced instead of the vinyl copolymer resin (B1) used in Example 2. Roll contamination did not occur at the time of continuous molding of the raw film. The thickness of the obtained stretched multilayer thermoplastic resin film was 40 m, and the thicknesses of the respective layers near the center thereof were (B5)/(A2)/(B5)=8 m/24 m/8 m. The evaluation results regarding continuous productivity, adhesion, transparency, mechanical strength, punching properties and dimensional stability were good, but the evaluation result regarding optical isotropy was poor. The synthetic judgement was failed (x).

Comparative Example 6 [Resin (A4)]

[0093] A single layer body was molded using a single layer extruder having a single screw extruder with a screw diameter of 65 mm and a T-die connected to the extruder. The thermoplastic resin composition (A4) obtained in Production Example 4 was continuously introduced into the single screw extruder and extruded at a cylinder temperature of 250 C. and a discharge rate of 50.0 kg/hour. The product was extruded into a sheet shape with the T-die connected to the extruder at 250 C., and it was cooled using 3 mirror surface rolls each at 90 C., 82 C. and 105 C. from the upstream side, thereby obtaining a raw film of the thermoplastic resin composition (A4). The thickness of the obtained raw film was 140 m. Roll contamination occurred at the time of continuous molding of the raw film. The obtained raw film was biaxially stretched using a fixed end simultaneous biaxial stretching machine. The stretching temperature was set at 150 C., the preheating time was sufficiently provided, the stretching rate was 300 mm/min, the stretching magnifications were 1.85 times (vertical) and 1.85 times (horizontal), and thus a stretched film of the thermoplastic resin composition (A4) was prepared. The thickness of the obtained stretched film of the thermoplastic resin composition (A4) was 40 m. The evaluation results regarding transparency and mechanical strength were good, but the evaluation results regarding continuous productivity, punching properties and dimensional stability were poor. The synthetic judgement was failed (x).

Comparative Example 7 [Resin (B6)]

[0094] A stretched film of the vinyl copolymer resin composition (B6) was obtained in a manner similar to that in Comparative Example 6, except that the vinyl copolymer resin composition (B6) obtained in Production Example 6 was introduced instead of the thermoplastic resin composition (A4) used in Comparative Example 6, and that the stretching temperature was set at 160 C. The thickness of the obtained stretched film of the thermoplastic resin composition (B6) was 40 sm. The evaluation results regarding transparency, optical isotropy, mechanical strength and dimensional stability were good, but the evaluation results regarding continuous productivity and punching properties were poor. The synthetic judgement was failed (x).

Comparative Example 8 [Resin (B7)]

[0095] A stretched film of the vinyl copolymer resin composition (B7) was obtained in a manner similar to that in Comparative Example 6, except that the vinyl copolymer resin composition (B7) obtained in Production Example 7 was introduced instead of the thermoplastic resin composition (A4) used in Comparative Example 6, and that the stretching temperature was set at 160 C. The thickness of the obtained stretched film of the vinyl copolymer resin composition (B7) was 40 m. The evaluation results regarding transparency, optical isotropy, mechanical strength and dimensional stability were good, but the evaluation results regarding continuous productivity and punching properties were poor. The synthetic judgement was failed (x).

Comparative Example 9 [Resin (A2)]

[0096] A stretched film of the thermoplastic resin composition (A2) was obtained in a manner similar to that in Comparative Example 6, except that the thermoplastic resin composition (A2) obtained in Production Example 2 was introduced instead of the thermoplastic resin composition (A4) used in Comparative Example 6. The thickness of the obtained stretched film of the thermoplastic resin composition (A2) was 40 m. The evaluation results regarding mechanical strength and punching properties were good, but the evaluation results regarding continuous productivity, transparency, optical isotropy and dimensional stability were poor. The synthetic judgement was failed (x).

TABLE-US-00001 TABLE 1 Evaluation Evaluation of mechanical Evaluation of Evaluation Evaluation strength of dimensional Syn- Constitution continuons Evaluation of trans- of optical Number of times Evaluation stability thetic Core Skin produc- of parency isotropy of folding of punching 85 C. judge- layer layer tivity adhesion Haze (%) Re (nm) Rth (nm) endurance properties 85% RH ment Example 1 Resin Resin (A1) (B1) 0/10 0.1 0.4 4.2 200 1.10% Example 2 Resin Resin (A2) (B1) 0/10 0.4 0.4 5.0 300 1.15% Example 3 Resin Resin (A3) (B1) 0/10 0.8 1.0 6.0 360 1.20% Example 4 Resin Resin (A2) (B2) 1/10 0.4 1.0 5.0 290 1.00% Compartive Resin Resin x x Example 1 (A4) (B1) 0/10 0.1 0.4 4.0 170 1.10% Comparative Resin Resin x x x x Example 2 (A5) (B1) 0/10 1.6 1.0 15.5 400 1.50% Comparative Resin Resin x x x Example 3 (A2) (B3) 5/10 0.4 1.0 5.2 300 1.10% Comparative Resin Resin x x Example 4 (A2) (B4) 0/10 0.4 1.0 9.5 270 10.50% Comparative Resin Resin x x x Example 5 (A2) (B5) 0/10 0.4 4.5 48.5 250 4.80% Comparative Resin (A4) x x x x x Example 6 0.1 1.0 10.3 202 14.72% Comparative Resin (B6) x x x Example 7 0.1 1.0 2.4 180 0.70% Comparative Resin (B7) x x x Example 8 0.1 1.0 2.0 160 0.60% Comparative Resin (A2) x x x x x Example 9 2.0 1.0 12.5 310 18.00%