JP2002105219A - Thermoplastic resin film, thermoplastic resin film for liquid crystal display element substrate, liquid crystal display element substrate and manufacturing method of thermoplastic resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin film which has a superior optical characteristic, an electrical characteristic and thermal dimension stability, also has an excellent adhesion for attaching a functional surface layer and is able to be used as a liquid crystal display element substrate. SOLUTION: This thermoplastic resin film whose glass transition temperature is above 150 deg.C, thickness exceeds 100 μm, retardation is below 20 nm and surface tension is above 37 dyne/cm is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin film, a thermoplastic resin film for a liquid crystal display element substrate, a liquid crystal display element substrate, and a method for producing a thermoplastic resin film. The present invention relates to a thermoplastic resin film suitable for a liquid crystal display element substrate having excellent adhesion between a thermoplastic resin film and a gas barrier layer or a hard coat layer provided on the film surface.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins having a high glass transition temperature and excellent optical properties have been industrially applied to various fields, and recently, liquid crystal display devices utilizing optical characteristics, particularly liquid crystal display device substrates. Deployment to is being considered. These days,
A liquid crystal display element of a portable information terminal is being developed for a liquid crystal display element taking advantage of its lightness and non-breakability, and a liquid crystal display element substrate capable of color display is required.

When such a thermoplastic resin is used for a liquid crystal display element substrate, characteristics similar to those of a conventionally used glass are required. That is, it has optical properties such as colorless and transparent, high light transmittance, heat resistance that can withstand processes such as lamination of a transparent electrode and an alignment film, and thermal dimensional stability. Many of these properties are due to the inherent properties of the resin, and various resins having excellent optical properties, heat resistance, and thermal dimensional stability have been developed. These include, for example, norbornene-based polymers (US Pat. No. 2,883,372, JP-A-1-14738, etc.) and ring-opened polymers of dicyclopentadiene (JP-B-58-43412, JP-A-63-218727). And the like.). These resins have a high glass transition point, are colorless and transparent, and have a high light transmittance, and thus are suitable as liquid crystal display element substrates.

However, when a gas barrier layer and a hard coat layer are provided on a thermoplastic resin film in order to provide the thermoplastic resin film with the oxygen barrier property and the water vapor barrier property, which are the features of glass, or the surface hardness so that the surface is hardly damaged. In addition, there is a problem that the layer is easily peeled off because the layer does not adhere to the surface of the thermoplastic resin film.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermoplastic resin film suitable for a liquid crystal display element substrate and having excellent adhesiveness when a functional layer is provided on the surface. It is in.

[0006]

That is, the thermoplastic resin film of the present invention is a film made of the thermoplastic resin A having a glass transition point of 150 ° C. or more, the film thickness is 100 μm or more, and the retardation is A thermoplastic resin film having a thickness of not more than 20 nm and a surface tension of the film of not less than 37 dyne / cm.

The thermoplastic resin film of the present invention is suitable for a liquid crystal display element substrate, and a liquid crystal display element substrate can be obtained using the thermoplastic resin film.

The method for producing a thermoplastic resin film of the present invention is characterized in that the thermoplastic resin B having a glass transition point of at least 150 ° C. is laminated on at least one surface of the thermoplastic resin A in a releasable state by melt coextrusion. The thermoplastic resin B was peeled off, the film thickness was 100 μm or more, the retardation was 20 nm or less, and the surface tension of the film was 37 dy.
This is a method for producing a thermoplastic resin film, characterized in that the film is n / cm or more.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Thermoplastic resin A in the present invention
In order to be used mainly as a liquid crystal display element substrate, the glass transition point needs to be 150 ° C. or higher. When the glass transition temperature is lower than 150 ° C., there is a problem that the film is deformed in a process of manufacturing a liquid crystal display element, for example, in a process of forming a transparent electrode or an alignment film.

As the thermoplastic resin A, alicyclic polyolefin, polyarylate, polysulfone, polyethersulfone, polycarbonate and the like are used, and alicyclic polyolefin is preferred in view of optical characteristics. Specific examples of the alicyclic polyolefin include a polymer having a structural unit represented by the following general formula [formula 1] and / or general formula [formula 2].

[0011]

Embedded image _{(Wherein, R 1, R 2, R} 3, R 4 is hydrogen, a hydrocarbon residue or a halogen, ester, nitrile, a polar group such as a pyridyl may be the same or different each, R _1, R ₂ , R ₃ and R ₄ may form a ring with each other; m is a positive integer; n and q are 0 or a positive integer.

[0012]

Embedded image _{(Wherein, R 5, R 6, R} 7, R 8 are hydrogen, a hydrocarbon residue or a halogen, ester, nitrile, a polar group such as a pyridyl may be the same or different from each other, R _5, R ₆ , R ₇ and R ₈ may form a ring with each other, k is a positive integer, l and p are 0 or a positive integer.) A structure represented by the general formula [Formula 1] Examples of the polymer having units include, as monomers, for example, norbornene and its alkyl and / or alkylidene-substituted product, for example, 5-methyl-2-norbornene, 5,6 dimethyl-
2-norbornene, 5-ethyl-2-norbornene, 5
-Butyl-2-norbornene, 5-ethylidene-2-norbornene and the like: dicyclopentadiene, 2,3-dihydrodicyclopentadiene, alkyl-substituted products thereof such as methyl, ethyl, propyl and butyl, and polar groups such as halogen Substituents: dimethanooctahydronaphthalene, its alkyl and / or alkylidene substituents, and polar group substituents such as halogens, for example, 6-methyl-1,
4: 5,8-Dimethano-1,4,4a, 5,6,7,
8,8a-octahydronaphthalene, 6-ethyl-1,
4: 5,8-dimethano 1,4,4a, 5,6,7,8,
8a-octahydronaphthalene, 6-ethylidene-1,
4: 5,8-Dimethano-1,4,4a, 5,6,7,
8,8a-octahydronaphthalene, 6-chloro-1,
4: 5,8-Dimethano-1,4,4a, 5,6,7,
8,8a-octahydronaphthalene, 6-cyano-1,
4: 5,8-Dimethano-1,4,4a, 5,6,7,
8,8a-octahydronaphthalene, 6-pyridyl-
1,4: 5,8-dimethano-1,4,4a, 5,6,
7,8,8a-octahydronaphthalene, 6-methoxycarbonyl-1, 4: 5,8-dimethano-1,4,4
a, 5, 6, 7, 8, 8a-octahydronaphthalene and the like: cyclopentadiene trimer to tetramer, for example, 4,
9: 5,8-Dimethano-3a, 4,4a, 5,8,8
a, 9, 9a-octahydro-1H-benzoindene,
4, 11: 5, 10: 6, 9-trimethano-3a, 4,
4a, 5, 5a, 6, 9, 9a, 10, 10a, 11,
It is produced by using one or more of 11a-dodecahydro-1H-cyclopentaanthracene and the like, and subjecting a ring-opened polymer obtained by polymerization by a known ring-opening polymerization method to hydrogenation by an ordinary hydrogenation method. It is a polymer.

In order to set the glass transition temperature of the target hydrogenated ring-opening polymer (saturated polymer) to 150 ° C., use tetramer or pentamer among these norbornene monomers, It is preferable to use these as main components and to use them together with a bicyclic or tricyclic monomer. In particular, from the viewpoint of birefringence, it is preferable to use a tetracyclic lower alkyl-substituted or alkenyl-substituted compound as a main component.

The polymer having the structural unit represented by the general formula [Chemical Formula 2] is obtained by subjecting at least one of the above-mentioned norbornene-based monomers and ethylene to addition polymerization by a known method. And / or hydrogenated products thereof, all of which are saturated polymers.

The alicyclic polyolefin is used as a molecular weight regulator in a process for producing a polymer having a structural unit represented by the general formula [1] and / or the general formula [2]. Α such as pentene, 1-hexene
-Intervening olefins or cyclopropene, cyclobutene, cyclopentene, cycloheptene,
It may be a polymer copolymerized by adding other monomer components such as cycloolefin such as cyclooctene and 5,6-dihydrocyclopentadiene as small components. These alicyclic polyolefins include JS
Preferred examples include Arton of R Co., Ltd., Zeonoa and Zeonex of Nippon Zeon Co., Ltd., and Apel of Mitsui Chemicals Co., Ltd.

The molecular weight of these alicyclic polyolefins is preferably such that the number average molecular weight measured by GPC (gel permeation chromatography) analysis using cyclohexane as a solvent is preferably from 10,000 to 300,000, more preferably from 2 to 200,000. It is ten thousand. When the unsaturated bonds remaining in the molecular chain are saturated by hydrogenation, the hydrogenation rate is 9%.
0% or more is preferable, and 95% or more is more preferable.
% Or more is more preferable. By being a saturated polymer, thermal dimensional stability is improved.

The preferred melt viscosity of the alicyclic polyolefin of the present invention is not particularly limited.
(Sec ⁻¹ ), preferably 1.5 × 10 ⁴ at 280 ° C.
poise or less, more preferably 1.0 × 10 ⁴ poise or less,
More preferably, the characteristics are particularly good in the case of 0.8 × 10 ⁴ poise or less.

The alicyclic polyolefin of the present invention may be used alone or in combination of two or more. In addition, the same species having different molecular weights may be blended. Further, an antioxidant, an antistatic agent, a lubricant, a surfactant, an ultraviolet absorber, and the like may be added to the alicyclic polyolefin of the present invention.

In the thermoplastic resin film of the present invention, the film made of the thermoplastic resin A has a thickness of 100 μm.
m or more, and preferably 150 μm or more. When the thickness is less than 100 μm, the rigidity of the film is small, so that the film is deformed in the manufacturing process of the liquid crystal display element, and the thermal dimensional stability cannot be obtained, which makes it difficult to manufacture the liquid crystal display element. The film thickness is normal without any quality problem.
The upper limit that can be produced industrially is about 2000 μm. As a method of controlling the film thickness, various known methods can be used, but a method of installing and controlling a measuring pump (specifically, a gear pump or the like) in the middle of the polymer pipe is generally used.

The retardation of the film made of the thermoplastic resin A is 20 nm or less, preferably 15 nm or less, more preferably 10 nm or less, further preferably 5 nm or less. By setting the retardation within the above range, colorless transparency can be maintained even when used as a liquid crystal display element substrate capable of performing color display. The lower limit of the retardation is 0 nm, which is the target. The meaning of the retardation is the in-plane anisotropy of the refractive index, and is defined by the product of the difference in the refractive index in the direction orthogonal to the in-plane and the film thickness.

The reduction in retardation can also be achieved by preparing a thermoplastic resin and then subjecting it to an aging treatment. The aging condition is, for example, in the range of (glass transition temperature −30 ° C.) to glass transition temperature for 30 minutes or more, preferably 2 hours to 96 hours.

This aging treatment is effective not only for lowering the retardation but also for alleviating the curl generated when wound in a roll.

In the production process of the thermoplastic resin film of the present invention, it is preferable that a film composed of the thermoplastic resin B is laminated on at least one surface of the film composed of the thermoplastic resin A in a releasable state. Thermoplastic resin A
Since the viscosity at the time of melting is high, the retardation tends to increase when a thick film is formed by melt film formation, but the retardation is reduced by laminating a film made of thermoplastic resin B from flow analysis at the time of melting. be able to. Furthermore, surface defects such as a streak and adhesion of dust can be prevented. As a method of laminating a film made of the thermoplastic resin A and a film made of the thermoplastic resin B, it is preferable that the thermoplastic resin A and the thermoplastic resin B are laminated in a die or an adapter when the thermoplastic resin A and the thermoplastic resin B are melted and coextruded. In order to cast the melt-coextruded polymer stably, it is preferable that the thermoplastic resin A and the thermoplastic resin B are uniformly laminated in the width direction except for the end of the film. The thickness of the thermoplastic resin B is preferably 2 μm or more, more preferably 10 μm or more, from the viewpoint of retardation. The normally used thickness has an upper limit of 100 μm in consideration of the rigidity of the film and the like. The peel strength of the film of thermoplastic resin B and thermoplastic resin A is 100 g
/ Cm, preferably 0.05 g / cm or more, 50 g
/ Cm, more preferably 0.2 g / cm or more. 10
If it is 0 g / cm or more, the thermoplastic resin B cannot be easily peeled off, while if it is less than 0.05 g / cm, it will peel off during the film forming process. The peeling force is based on the crystallinity of the laminated resin used,
Depends on crystallinity.

The thermoplastic resin B used in the present invention is not particularly limited, but polyester is preferably used from the viewpoint of releasability from the thermoplastic resin A. Among the polyesters, polyesters containing polyethylene terephthalate, polyethylene naphthalate, polyethylene isophthalate and polypropylene terephthalate as main components are more preferable, and polyethylene terephthalate as the main component is most preferable.

Here, the main component indicates that it is 80% by weight or more, and if it is less than 20% by weight, the third component may be copolymerized or blended. Examples of the copolymer component include a dicarboxylic acid component and a diol component.
Examples of the dicarboxylic acid component used as a copolymerization component include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, trimethyladipic acid, sebacic acid, malonic acid, dimethylmalonic acid, succinic acid, glutaric acid, and pimerine. Acid, 2,2-dimethylglutaric acid, azelaic acid, fumaric acid, maleic acid, itaconic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1, 4-naphthalic acid, diphenic acid,
4,4'-oxybenzoic acid and 2,5-naphthalenedicarboxylic acid can be used. Of these, isophthalic acid, naphthalenedicarboxylic acid, cyclohexanedicarboxylic acid, and diphenylethanedicarboxylic acid are preferred.

The diol component used as the copolymer component includes ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. 1,1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl-2 -Ethylhexane-1,
3-diol, neopentyl glycol, 2-ethyl-
2-butyl-1,3-propanediol, 2-ethyl-
2-isobutyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexane Dimethanol, 1,4-cyclohexanedimethanol, 2,2,
4,4-tetramethyl-1,3-cyclobutanediol, 4,4′-thiodiphenol, bisphenol A,
4,4′-methylenediphenol, 4,4 ′-(2-norbornylidene) diphenol, 4,4′-dihydroxybiphenol, o-, m-, and p-dihydroxybenzene, 4,4′-isopropylidenephenol ,
4,4′-isopropylidenebis (2,6-dichlorophenol), 2,5-naphthalenediol, p-xylenediol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,
4-diol and the like can be used. Of these, propylene glycol, tetramethylene glycol and cyclohexanedimethanol are preferably used.

In addition to the dicarboxylic acid component and the diol component, an oxycarboxylic acid such as p-oxybenzoic acid may be copolymerized. Further, these have a linear structure, but have a trivalent or higher valence. Branched polyesters can also be formed using ester-forming components. Further, examples of the blend include the above-mentioned polyester, copolymerized polyester, polycarbonate resin, acrylic resin, polyolefin resin and the like.

The intrinsic viscosity of the polyester used as the thermoplastic resin B of the present invention is preferably 0.65 dl /
g, more preferably 0.7 dl / g or more. In this range, the flowability at the time of melting is improved, the retardation is reduced, and the wraparound to the edge of the film is suppressed, so that a uniform laminated film can be obtained.

The thermoplastic resin B used in the present invention includes:
Inert particles may be added, and as the inert particles, silica, alumina, calcium carbonate, calcium phosphate,
Examples include inorganic particles such as barium sulfate, magnesium oxide, zinc oxide, and titanium oxide, and organic polymer particles (for example, crosslinked polystyrene particles and acrylic particles).
If necessary, a flame retardant, a heat stabilizer, a plasticizer, an antioxidant, an ultraviolet absorber, an antistatic agent, a pigment, an organic lubricant such as a fatty acid ester and a wax, and the like may be blended. You may use together.

The surface tension of the film made of the thermoplastic resin A of the present invention is at least 37 dyne / cm, preferably 38 dyne / cm, from the viewpoint of adhesion to a functional layer provided on the surface.
cm or more, more preferably 40 dyne / cm or more. When the surface tension is less than 37 dyne / cm, when a functional layer such as a gas barrier layer or a hard coat layer is provided on the surface, the adhesiveness is poor and easily peeled off. The upper limit of the surface tension is not limited to this, but is about 72 dyne / cm.

The surface tension is not particularly limited, but is preferably 5 to 100 W · min / min in the air, in a nitrogen gas atmosphere, or in a carbon dioxide gas atmosphere. A preferred example is a method of corona treatment in the range of m ² . In addition, the surface of the film made of the thermoplastic resin A may be subjected to a known method, for example, a surface treatment method comprising one selected from plasma treatment, chemical treatment, ion implantation treatment, flame treatment, coating treatment, or a combination thereof. Are also preferably exemplified. As the atmosphere gas at the time of the surface treatment, it is more preferable to perform the treatment in a vacuum free of oxygen than in air and in the presence of nitrogen gas, carbon dioxide gas, organic gas, or the like.

Next, a method for producing the thermoplastic resin film of the present invention will be described, but the present invention is not limited thereto.

The content of low-molecular-weight substances having a molecular weight of less than 100, such as water, volatiles and decomposition products, is preferably reduced to 0.05% by weight or less from the thermoplastic resin A, and then supplied to an extruder to be melted. I do. On the other hand, the thermoplastic resin B is also supplied to another extruder and melted after excluding low molecular weight substances such as moisture,
The melted thermoplastic resin A is laminated in a composite die or an adapter. At this time, it is preferable to laminate the thermoplastic resin B on both surfaces of the thermoplastic resin A in order to reduce the retardation based on the flow analysis during melting. A molten sheet is discharged from a lip of a thermoplastic resin base and brought into close contact with a cooling drum to obtain a cast sheet. Casting method includes nip roll method, calendar method, electrostatic application adhesion method,
An air knife method, an air chamber method, or the like can be used. In the case of the present invention, the air knife method is preferable. It is preferable to use a drum made of chromium plating or stainless steel and having a surface roughness Rmax of 0.2 μm or less. Although the surface temperature of the drum is not particularly limited, it depends on the crystallinity of the thermoplastic resin B and the adhesiveness between the drum and the optical properties of the thermoplastic resin A, but it is 20 to 180 ° C, preferably 40 to 150 ° C. Things are often used. Further, it is preferable that the draft ratio (the ratio of the discharge gap of the die / the thickness of the solidified film) be 20 or less, and more preferably 10 or less, because the film becomes optically isotropic.

On the surface of the film made of thermoplastic resin A,
A surface treatment method including one selected from a corona treatment, a plasma treatment, a chemical treatment, an ion implantation treatment, a flame treatment, a coating treatment, or a combination thereof is performed.

A gas barrier layer and a hard coat layer are formed on the thermoplastic resin film obtained by the present invention, if necessary, by a known method, and then a transparent electrode is formed and used as a liquid crystal display element substrate.

As the gas barrier layer, a transparent vapor-deposited layer such as a polyvinyl alcohol film, a silica film, or an alumina film may be coated. Among them, the gas barrier properties require characteristics such as moisture resistance, alkali resistance, and acid resistance. Therefore, a large amount of an inorganic substance such as silica having an average particle size of about 5 to 25 nm is added to the organic polymer compound in a large amount. It is preferable to laminate an organic polymer crosslinked layer. In addition,
The fine particles are not particularly limited, but silica sol, antimony oxide sol, titania sol, alumina sol, zirconia sol, tungsten oxide sol, and the like are preferably exemplified.The average particle diameter of the particles is 1 to 300 nm in applications where transparency is required. Preferably 5 to 100 nm,
More preferably, it is 10 to 50 nm. The addition content of these particles is 10 to 85% by weight, preferably 3 to 85% by weight.
A range of 5 to 70% by weight is preferred. A surfactant may be added to these layers.

Next, a hard coat film is coated on the gas barrier film. In this case, the organic high molecular compound is not particularly limited, but an epoxy resin, an acrylic resin, a urethane resin, a urea resin, a melamine resin, and a modified product thereof are preferably exemplified. Further, a water / alcohol dispersion liquid to which an inorganic oxide such as silica having an average particle diameter of about 10 to 50 nm is added in an amount of about 50 to 85% by weight, and a catalyst represented by an aluminum chelate compound as a crosslinking agent is added as necessary. After coating,
Crosslinking is performed by heat, electron beam, radiation or the like to form a hard coat layer of 3H or more.

After providing these layers, the sheet is cut into a sheet, and aging is performed by applying a suitable load below the glass transition point by the above-described method. It is particularly preferable for improving the properties. Thus, the thermoplastic resin film for a liquid crystal display element substrate of the present invention is obtained. The aging conditions are (glass transition temperature -30
C.) to a glass transition temperature in the range of 30 minutes or more, preferably 2 hours to 96 hours.

[Method of Evaluating Characteristics] The method of measuring and evaluating the characteristic values in the present invention is as follows.

(1) Retardation Using a sodium D line (589 nm) as a light source, place the sample film surface perpendicular to the optical axis on a polarizing microscope equipped with orthogonal Nicols, and retardation caused by the birefringence n of the sample film. Rd was determined from the compensation value of the compensator.

(2) Surface Roughness The center line average roughness Ra and Rmax were measured using a three-dimensional roughness meter (ET-30HK) manufactured by Kosaka Laboratory. The measurement conditions are as follows. The value was an average value of 20 measurements. Stylus tip radius: 2 μm Stylus load: 16 mg Measurement area: 0.3 mm ² Cut off: 0.25 mm (3) Lamination thickness, film thickness After peeling off the lamination film, each thickness is measured with a dial gauge. did.

(4) Intrinsic Viscosity The value calculated by the following equation from the melt viscosity measured in orthochlorophenol at 25 ° C. was used. That is, ηsp / C
= [Η] + 2K [η] C (where ηsp = (solution viscosity /
Solvent viscosity) -1, C is the weight of dissolved polymer per 100 ml of solvent (g / 100 ml), K is the Huggins constant (0.
343)). Solution viscosity and solvent viscosity were measured with an Ostwald viscometer.

(5) Surface tension Measured according to JIS K-6768.

(6) Glass transition temperature As a differential scanning calorimeter, DS manufactured by Seiko Instruments Inc.
C (RDC220), using the company's disk station (SSC / 5200) as a data analyzer,
5 mg at 300 ° C.
After holding for 1 min and quenching with liquid nitrogen,
Measured in. The glass transition temperature was the temperature at the midpoint of the glass transition.

(6) Thermal dimensional stability (thermal dimensional change starting temperature) The temperature was raised from 30 ° C. to 300 ° C. at a rate of 20 ° C./min using TMA, and the temperature was plotted on the horizontal axis and the dimensional change was plotted on the vertical axis. At this time, a point deviating from a straight line below the glass transition temperature was determined as a thermal dimensional change starting temperature.

(7) Adhesiveness Aluminum was vapor-deposited on the film surface to a thickness of 200 angstroms, and a cross-cut of 90 mm was formed on the vapor-deposited layer.
I put them. After sticking a cellophane tape from Nichiban Co., Ltd. on the cross cut of the vapor deposition layer,
The number remaining after peeling at 80 degrees was determined. When 70 or more were left, it was evaluated as ○, when less than 70, 50 or more, Δ, and when less than 50, ×.

[0047]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

(Example 1) As the thermoplastic resin A, an alicyclic polyolefin ("Zeonor" manufactured by Zeon Corporation) was used.
After vacuum drying at 130 ° C. for 4 hours using a glass transition point of 163 ° C.), the mixture was supplied to an extruder A and melted at 280 ° C.

On the other hand, as the thermoplastic resin B, polyethylene terephthalate (intrinsic viscosity: 1.4 dl / g) was used.
After vacuum drying for 6 hours at 180 ° C.,
Melted at 80 ° C., three layers (thermoplastic resin B / thermoplastic resin A / thermoplastic resin B) are laminated in the adapter with thermoplastic resin A supplied from extruder A, and then discharged and melted from a die I got a sheet. The molten sheet was closely adhered to a chrome plating roll maintained at 70 ° C. and solidified by cooling to obtain a laminated film having a laminated thickness ratio B / A / B = 20/200/20.

The layer B on one side is peeled from the laminated film, and the film surface of the thermoplastic resin A after the layer B is peeled off is subjected to corona discharge treatment (40 W · min / m ² ) in air.
And aged at 140 ° C. for 24 hours. Table 1 shows the properties of the obtained film.

(Example 2) As the thermoplastic resin A, an alicyclic polyolefin ("Zeonor" manufactured by Zeon Corporation),
After vacuum drying at 130 ° C. for 4 hours using a glass transition point of 163 ° C.), the mixture was supplied to an extruder A and melted at 280 ° C.

On the other hand, as the thermoplastic resin B, polyethylene terephthalate (intrinsic viscosity: 1.4 dl / g) was used.
After vacuum drying for 6 hours at 180 ° C.,
Melted at 80 ° C., three layers (thermoplastic resin B / thermoplastic resin A / thermoplastic resin B) are laminated in the adapter with thermoplastic resin A supplied from extruder A, and then discharged and melted from a die I got a sheet. The molten sheet was brought into close contact with a chromium plating roll maintained at 70 ° C. and solidified by cooling to obtain a laminated film having a laminated thickness ratio B / A / B = 50/400/50.

The layer B on one side was peeled from the laminated film, and the film surface of the thermoplastic resin A after peeling the layer B was subjected to corona discharge treatment (40 W · min / m ² ). At this time, the surface tension of the thermoplastic resin A surface is 39 dy.
ne / cm. Next, reactive vapor deposition of alumina was applied as a transparent vapor-deposited layer, and 45 wt% of polyvinyl alcohol and 55 wt% of a spherical colloidal silica sol having an average particle size of 13 nm (silica solid content 1
0% by weight) and a gas barrier coat using a water / methanol dispersion of aluminum acetylacetonate as a crosslinking agent was cured at 150 ° C., coated to a thickness of 1 μm, and wound up on a roll.

A hard coat layer was further provided on the surface coated with the gas barrier layer. That is, 30% by weight of an acrylic resin and 70% by weight of spherical colloidal silica having an average particle diameter of 45 nm were cured by UV to have a thickness of 2 μm.

On the other side, similarly, after peeling the layer B, the film surface of the thermoplastic resin A is subjected to a corona discharge treatment (40 W · min / m ² ) to provide a gas barrier layer and a hard coat layer. Layer / gas barrier layer / thermoplastic resin A / gas barrier layer / hard coat layer
Obtain a layer configuration, cut this into 300 x 300 mm sheets,
A load of 10 g / cm ² was applied to the laminated body in which 500 single sheets were stacked and aged at 145 ° C. for 12 hours. Table 1 shows the properties of the obtained film.

Comparative Example 1 Table 1 shows the properties of a film made of thermoplastic resin A obtained in the same manner as in Example 1 except that no corona treatment was performed.

[0057]

[Table 1]

[0058]

According to the present invention, a thermoplastic resin film having excellent surface smoothness, low retardation and thermal dimensional stability can be obtained, and a film having excellent adhesiveness when a surface functional layer is provided can be obtained. . This thermoplastic resin film can be suitably used as a liquid crystal display element substrate.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H090 HB07X HB17X HC05 HC13 HC18 HD01 JB03 JB13 JC07 JC09 JD08 JD17 4F071 AA21 AA50 AA51 AA64 AA86 AF31 AG28 AH12 BB06 BC01 BC12 4F100 AK02ABABA BA02 AS00 BA03 BA00 AS02A03 EJ412 EJ552 GB41 JA05A JA20A JD02B JJ03 JL04 JL11 JN18A

Claims (7)

[Claims] 1. A film made of a thermoplastic resin A having a glass transition point of 150 ° C. or higher, and having a film thickness of 1
A thermoplastic resin film having a thickness of at least 00 μm, a retardation of at most 20 nm, and a surface tension of at least 37 dyne / cm. 2. The thermoplastic resin film according to claim 1, wherein the thermoplastic resin A is an alicyclic polyolefin. 3. A thermoplastic resin film for a liquid crystal display element substrate, wherein the thermoplastic resin film according to claim 1 or 2 is used for a liquid crystal display element substrate. 4. A liquid crystal display element substrate using the thermoplastic resin film for a liquid crystal display element substrate according to claim 3. 5. A thermoplastic resin B having a glass transition point of at least 150 ° C. is laminated on at least one surface of the thermoplastic resin A by melt coextrusion in a releasable state.
The film surface of the thermoplastic resin A is subjected to a surface treatment, the film thickness is 100 μm or more, the retardation is 20 nm or less, and the surface tension of the film is 37 dy.
A method for producing a thermoplastic resin film, characterized in that the film has a thickness of at least n / cm. 6. The method for producing a thermoplastic resin film according to claim 5, wherein aging is performed at a temperature equal to or lower than the glass transition point. 7. A liquid crystal display element substrate for a liquid crystal display element substrate, comprising: providing a gas barrier layer and / or a hard coat layer on at least one surface of the thermoplastic resin film according to claim 1 and cutting the sheet into a sheet. A method for producing a thermoplastic resin film.