JPH11119024A - Polarizing film - Google Patents

Abstract

(57) [Problem] To provide a polarizing film having excellent moldability, heat resistance, mechanical properties, gas barrier properties, etc., flexibility, and good polarization. SOLUTION: A polarizing film comprising a liquid crystal polyester resin composition having (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase, and at least (A) A layer comprising a liquid crystal polyester resin composition having A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase; and a thermoplastic resin (provided that the liquid crystal polyester and (A liquid crystal polyester resin composition is excluded)).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in heat resistance, gas barrier properties, mechanical strength and flexibility, and has a degree of polarization,
The present invention relates to a polarizing film having good appearance and the like.

[0002]

2. Description of the Related Art In recent years, with the spread of liquid crystal displays,
Although the demand for polarizing films is increasing remarkably, on the other hand, conventional resin-made polarizing films cannot sufficiently meet the demands from the market.

For example, a polarizing film obtained by dyeing a dichroic dye on a polyvinyl alcohol film has been widely used, but it has been pointed out that gas barrier properties and heat resistance are insufficient. It is also said that a polarizing film using polyvinyl chloride or polyvinylidene chloride has insufficient heat resistance and gas barrier properties.

Japanese Patent Application Laid-Open No. 58-124621 discloses a polarizing film using polyamide or the like, but has insufficient heat resistance and polarizing performance. JP 6
JP-A-2-204202, JP-A-63-61203 and the like describe a polarizing film using a liquid crystal polymer. However, the polarizing film has remarkable anisotropy in mechanical strength, and it is difficult to reduce the thickness. Yes, and lacked flexibility. JP-A-4-288503 describes a polarizing sheet comprising a composition containing a thermoplastic resin and a liquid crystal polymer, but has insufficient heat resistance and gas barrier properties. Although the publication describes a polarizing film using a liquid crystal polymer, heat resistance, mechanical strength, and the like were insufficient.

[0005]

The problems to be solved by the present invention in view of the above situation are excellent in moldability, heat resistance, mechanical properties, gas barrier properties, etc., flexibility, and good polarization. It is to provide a polarizing film.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides a polarizing film comprising a liquid crystal polyester resin composition having (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase, and at least: (A)
A layer composed of a liquid crystal polyester resin composition having a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase; and a thermoplastic resin (provided that the liquid crystal polyester and the liquid crystal (Excluding the polyester resin composition)).

[0007]

Next, the present invention will be described in more detail. The liquid crystal polyester of the component (A) of the liquid crystal polyester resin composition in the present invention is a polyester called a thermotropic liquid crystal polymer.

[0008] Specifically, (1) a combination of an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid. (2) Those comprising a combination of different aromatic hydroxycarboxylic acids. (3) Those comprising a combination of an aromatic dicarboxylic acid and a nucleus-substituted aromatic diol. (4) Those obtained by reacting an aromatic hydroxycarboxylic acid with a polyester such as polyethylene terephthalate. And the like, which forms an anisotropic melt at a temperature of 400 ° C. or lower. In addition, in place of these aromatic dicarboxylic acids, aromatic diols, and aromatic hydroxycarboxylic acids, ester-forming derivatives thereof may be used.

The repeating structural units of the liquid crystal polyester include the following repeating structural units derived from an aromatic dicarboxylic acid, the following repeating structural units derived from an aromatic diol,
Examples of the repeating structural unit derived from an aromatic hydroxycarboxylic acid include, but are not limited to, these.

A repeating structural unit derived from an aromatic dicarboxylic acid:

[0011]

A repeating structural unit derived from an aromatic diol:

[0013]

A repeating structural unit derived from an aromatic hydroxycarboxylic acid:

A liquid crystal polyester which is particularly preferable from the balance of heat resistance, mechanical properties and workability is And more preferably at least 30 mol% or more of such a repeating structural unit. Specifically, the combination of repeating structural units is preferably any one of the following (I) to (VI).

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

The production methods of the liquid crystal polyesters (I) to (VI) are described, for example, in JP-B-47-47870, JP-B-63-3888, JP-B-63-3891, and JP-B-56-18016. JP-A-2-515
No. 23, and the like. Of these, a combination of (I), (II) or (IV) is preferable, and a combination of (I) or (II) is more preferable.

In the field where high heat resistance is required in the present invention, the liquid crystal polyester of the component (A) contains 30 to 80 mol% of the following repeating unit (a ') and 0 to 100% of the repeating unit (b'). 10 mol%, repeating unit (c ') is 1
A liquid crystal polyester having 0 to 25 mol% and a repeating unit (d ') of 10 to 35 mol% is preferably used.

[0024] (In the formula, Ar is a divalent aromatic group.)

For the polarizing film of the present invention, the field in which easy disposal such as incineration after use is demanded from the viewpoint of environmental problems is one of the preferred combinations of the fields required so far. , Hydrogen and oxygen are particularly preferably used.

The component (B) used in the liquid crystal polyester resin composition of the present invention is a copolymer having a functional group reactive with the liquid crystal polyester. The functional group reactive with the liquid crystal polyester is not particularly limited as long as it has reactivity with the liquid crystal polyester, and specific examples include an oxazolyl group, an epoxy group, and an amino group. Preferably, it is an epoxy group. The epoxy group or the like may be present as a part of another functional group, and such an example includes a glycidyl group.

In the copolymer (B), the method for introducing such a functional group into the copolymer is not particularly limited, and it can be carried out by a known method. For example, at the stage of synthesizing the copolymer, it is possible to introduce the monomer having the functional group by copolymerization, or it is also possible to graft copolymerize the monomer having the functional group to the copolymer. It is.

As the monomer having a functional group reactive with the liquid crystal polyester, and particularly as the monomer containing a glycidyl group, unsaturated glycidyl carboxylate and / or unsaturated glycidyl ether are preferably used.

The unsaturated carboxylic acid glycidyl ester preferably has the general formula Wherein R is a hydrocarbon group having an ethylenically unsaturated bond and having 2 to 13 carbon atoms. The unsaturated glycidyl ether is preferably a compound represented by the general formula: (R is a hydrocarbon group having 2 to 18 carbon atoms which has an ethylenically unsaturated bond, X is -CH ₂ -O- or It is. ).

Specifically, examples of the unsaturated carboxylic acid glycidyl ester include glycidyl acrylate, glycidyl methacrylate, itaconic acid diglycidyl ester, butenetricarboxylic acid triglycidyl ester,
Glycidyl p-styrenecarboxylate and the like can be mentioned. As unsaturated glycidyl ethers,
For example, vinyl glycidyl ether, allyl glycidyl ether, 2-methylallyl glycidyl ether, methacryl glycidyl ether, styrene-p-glycidyl ether and the like are exemplified.

The copolymer (B) having a functional group reactive with the liquid crystal polyester preferably contains 0.1 to 30% by weight of an unsaturated carboxylic acid glycidyl ester unit and / or an unsaturated glycidyl ether unit. It is a copolymer containing.

The copolymer (B) having a functional group reactive with the liquid crystal polyester may be a thermoplastic resin or a rubber, or a mixture of a thermoplastic resin and a rubber. You may. Rubber is preferred because it has better flexibility and thermal stability.

More preferably, the copolymer (B) having a functional group reactive with the liquid crystal polyester is
A copolymer having a heat of fusion of crystal of less than 3 J / g. The copolymer (B) preferably has a Mooney viscosity of 3 to 70, more preferably 3 to 30 and more preferably 4 to 30.
25 are particularly preferred. The Mooney viscosity here refers to a value measured using a large rotor at 100 ° C. according to JIS K6300.

The rubber referred to here is a polymer substance having rubber elasticity at room temperature according to a new edition of Polymer Dictionary (edited by the Society of Polymer Science, published in 1988, Asakura Shoten).
Specific examples thereof include natural rubber, butadiene polymer, butadiene-styrene copolymer (including random copolymer, block copolymer (including SEBS rubber or SBS rubber, etc.), and graft copolymer), or The hydrogenated product, isoprene polymer, chlorobutadiene polymer, butadiene-acrylonitrile copolymer, isobutylene polymer, isobutylene-butadiene copolymer rubber,
Isobutylene-isoprene copolymer, acrylate-ethylene copolymer rubber, ethylene-propylene copolymer rubber, ethylene-butene copolymer rubber, ethylene-propylene-styrene copolymer rubber, styrene-isoprene copolymer Rubber, styrene-butylene copolymer, styrene-ethylene-propylene copolymer rubber, perfluoro rubber, fluoro rubber, chloroprene rubber, butyl rubber, silicone rubber, ethylene-propylene-non-conjugated diene copolymer rubber, thiol rubber, polysulfide Examples include rubber, polyurethane rubber, polyether rubber (for example, polypropylene oxide, etc.), epichlorohydrin rubber, polyester elastomer, polyamide elastomer, and the like. Among them, an acrylate-ethylene copolymer is preferably used, and a (meth) acrylate-ethylene copolymer rubber is more preferred.

These rubber-like substances can be produced by any production method (eg, emulsion polymerization method, solution polymerization method, etc.) and any catalyst (eg, peroxide, trialkylaluminum, lithium halide, nickel-based catalyst, etc.). It may be something.

In the present invention, the copolymer (B)
Is a rubber having a functional group reactive with the liquid crystal polyester in the rubber as described above. In such a rubber, a method for introducing a functional group reactive with the liquid crystal polyester into the rubber is not particularly limited, and can be performed by a known method. For example, it is possible to introduce the monomer having the functional group by copolymerization at the stage of synthesizing the rubber, or it is also possible to graft copolymerize the monomer having the functional group to the rubber.

As specific examples of the copolymer (B) having a functional group reactive with the liquid crystal polyester, rubbers having an epoxy group include (meth) acrylate-ethylene- (unsaturated glycidyl carboxylate and And / or unsaturated glycidyl ether) copolymer rubber.

Here, the (meth) acrylic acid ester is
An ester obtained from acrylic acid or methacrylic acid and an alcohol. Alcohols have 1 carbon atom
~ 8 alcohols are preferred. Specific examples of (meth) acrylates include methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, ter
Examples thereof include t-butyl methacrylate, 2-ethylhexyl acrylate, and 2-ethylhexyl methacrylate. As the (meth) acrylic acid ester, one kind thereof may be used alone, or two or more kinds may be used in combination.

Preferably, the content of (meth) acrylate units is more than 40% by weight and less than 97% by weight, more preferably 45 to 70% by weight, and the ethylene unit is 3% by weight to 5% by weight.
0% by weight, more preferably 10 to 49% by weight, 0.1 to 30% by weight of unsaturated carboxylic acid glycidyl ether unit and / or unsaturated glycidyl ether unit,
More preferably, it is 0.5 to 20% by weight. Outside the above range, the thermal stability and mechanical properties of the film obtained from the composition may be insufficient, which is not preferred.

The copolymer rubber can be produced by a conventional method, for example, bulk polymerization, emulsion polymerization, solution polymerization or the like using a free radical initiator. Typical polymerization methods are described in JP-B-46-45085 and JP-B-6-45085.
No. 1-127709, pressure of 500 k in the presence of a polymerization initiator generating free radicals
g / cm ² or more and a temperature of 40 to 300 ° C.

Other rubbers that can be used in the copolymer (B) of the present invention include acrylic rubber having a functional group reactive with the liquid crystal polyester and vinyl aromatic having a functional group reactive with the liquid crystal polyester. Hydrocarbon compounds
A conjugated diene compound block copolymer rubber can also be exemplified.

The acrylic rubber mentioned here is preferably represented by the general formula (1) (In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms or a cyanoalkyl group.), A general formula (2) (Wherein, R ² is an alkylene group having 1 to 12 carbon atoms, R ³
Represents an alkyl group having 1 to 12 carbon atoms. ) And general formula (3) (Wherein, R ⁴ is a hydrogen atom or a methyl group, R ^{5 is} an alkylene group having 3 to 30 carbon atoms, R ⁶ is an alkyl group having 1 to 20 carbon atoms or a derivative thereof, and n is an integer of 1 to 20) .)) At least one monomer selected from the compounds represented by formula (1).

Specific examples of the alkyl acrylate represented by the general formula (1) include, for example, methyl acrylate, ethyl acrylate, propyl acrylate,
Examples thereof include butyl acrylate, pentyl acrylate, hexyl acrylate, actyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, and cyanoethyl acrylate.

The alkoxyalkyl acrylate represented by the general formula (2) includes, for example, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, ethoxypropyl acrylate and the like. One or more of these can be used as the main component of the acrylic rubber.

As a constituent component of the acrylic rubber, an unsaturated monomer copolymerizable with at least one monomer selected from the compounds represented by the above general formulas (1) to (3), if necessary. Can be used. Examples of such unsaturated monomers include styrene, α-methylstyrene,
Acrylonitrile, halogenated styrene, methacrylonitrile, acrylamide, methacrylamide, vinylnaphthalene, N-methylolacrylamide, vinyl acetate, vinyl chloride, vinylidene chloride, benzyl acrylate, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and the like. .

The preferred constituent ratio of the acrylic rubber having a functional group reactive with the liquid crystal polyester is at least one monomer selected from the compounds represented by the above general formulas (1) to (3). 0 to 99.9% by weight, 0.1 to 30.0% by weight of unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether, selected from the compounds represented by the above general formulas (1) to (3). Unsaturated monomer copolymerizable with at least one monomer 0.0
３30.0% by weight. When the constituent ratio of the acrylic rubber is within the above range, heat resistance and impact resistance of the composition,
The molding processability is good and preferable.

The method for producing the acrylic rubber is not particularly limited. For example, JP-A-59-113010, JP-A-62-64809, and JP-A-3-160008
Or a well-known polymerization method described in WO95 / 04764 or the like, and can be produced by emulsion polymerization, suspension polymerization, solution polymerization or bulk polymerization in the presence of a radical initiator. .

The vinyl aromatic hydrocarbon compound-conjugated diene compound block copolymer rubber having a functional group reactive with the liquid crystal polyester is preferably (a)
Epoxidation of a rubber obtained by epoxidizing a block copolymer consisting of a sequence mainly composed of a vinyl aromatic hydrocarbon compound and (b) a sequence mainly composed of a conjugated diene compound, or epoxidation of a hydrogenated product of the block copolymer This is the rubber obtained.

The vinyl aromatic hydrocarbon compound-conjugated diene compound block copolymer or a hydrogenated product thereof can be produced by a known method.
798 and JP-A-59-133203.

As the aromatic hydrocarbon compound, for example,
Styrene, vinyltoluene, divinylbenzene, α-methylstyrene, p-methylstyrene, vinylnaphthalene and the like can be mentioned, among which styrene is preferable.
Examples of the conjugated diene compound include butadiene, isoprene, pyrrylene, 1,3-pentadiene, 3-butyl-1,3-octadiene and the like, butadiene or isoprene is preferred.

The rubber used as the copolymer (B) is preferably (meth) acrylate-ethylene-
(Unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber is used.

The rubber used as the copolymer (B) can be vulcanized as required and used as a vulcanized rubber. The above (meth) acrylic acid ester-ethylene-
Vulcanization of the (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber is achieved by using a polyfunctional organic acid, a polyfunctional amine compound, an imidazole compound, and the like. It is not limited.

As a specific example of the copolymer (B) having a functional group reactive with the liquid crystal polyester, the thermoplastic resin having an epoxy group includes (a) 50 to 99% by weight of ethylene units, (b) ) 0.1 to 30% by weight, preferably 0.5 to 20% by weight of unsaturated carboxylic acid glycidyl ester units and / or unsaturated glycidyl ether units.
% By weight, and (c) an epoxy group-containing ethylene copolymer having an ethylenically unsaturated ester compound unit of 0 to 50% by weight.

Examples of the ethylenically unsaturated ester compound (c) include vinyl carboxylate such as vinyl acetate, vinyl propionate, methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate. Esters, α, β-unsaturated carboxylic acid alkyl esters, and the like. Particularly, vinyl acetate, methyl acrylate and ethyl acrylate are preferred.

Specific examples of the epoxy group-containing ethylene copolymer include, for example, a copolymer composed of ethylene units and glycidyl methacrylate units, a copolymer composed of ethylene units and glycidyl methacrylate units, and a methyl acrylate unit. Copolymers composed of glycidyl methacrylate units and ethyl acrylate units, and copolymers composed of ethylene units, glycidyl methacrylate units and vinyl acetate units are exemplified.

The epoxy group-containing ethylene copolymer has a melt index (hereinafter sometimes referred to as MFR. JI.
SK6760, 190 ° C, 2.16 kg load) is preferably 0.5 to 100 g / 10 min, more preferably 2 to 100 g / 10 min.
５０50 g / 10 min. The melt index may be outside this range, but the melt index is 100 g
If it exceeds / 10 minutes, it is not preferable in view of the mechanical properties of the composition, and if it is less than 0.5 g / 10 minutes, the compatibility with the liquid crystal polyester of the component (A) is inferior.

[0057] Also, the epoxy group-containing ethylene copolymer is preferably in the range stiffness modulus of 10~1300kg / cm ^2, further preferably from 20~1100kg / cm ^2. If the flexural rigidity is outside this range, the molding processability and mechanical properties of the composition may be insufficient, which is not preferable.

The epoxy group-containing ethylene copolymer is usually prepared by reacting an unsaturated epoxy compound and ethylene in the presence of a radical generator at 500 to 4000 atm and 100 to 300 ° C. in the presence or absence of a suitable solvent or chain transfer agent. It is produced by a high-pressure radical polymerization method in which copolymerization is carried out in the presence. It can also be produced by a method in which an unsaturated epoxy compound and a radical generator are mixed with polyethylene and melt-grafted and copolymerized in an extruder.

The liquid crystal polyester resin composition of the present invention comprises:
A resin composition containing the above liquid crystal polyester,
A resin composition comprising (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase. If the liquid crystal polyester is not in a continuous phase, the polarizing film made of the liquid crystal polyester resin composition may have significantly reduced gas barrier properties and heat resistance, which is not preferable.

The details of the mechanism of such a resin composition of a copolymer having a functional group and a liquid crystal polyester are unknown, but the resin composition between the component (A) and the component (B) of the composition is not clear. It is considered that a reaction occurs, and the component (A) forms a continuous phase, and the component (B) is finely dispersed, thereby improving the moldability of the composition.

One embodiment of the liquid crystal polyester resin composition of the present invention comprises (A) 56.0 to 99.
9% by weight, preferably 65.0 to 99.9% by weight, more preferably 70 to 98% by weight, and (B) a copolymer 4 having a functional group reactive with the liquid crystal polyester
It is a resin composition containing 4.0 to 0.1% by weight, preferably 35.0 to 0.1% by weight, more preferably 30 to 2% by weight. If the content of the component (A) is less than 56.0% by weight, the gas barrier properties and heat resistance of the composition may be undesirably reduced. On the other hand, if the component (A) exceeds 99.9% by weight, the moldability may be reduced, and the cost is high, which is not preferable.

As a method for producing the liquid crystal polyester resin composition in the present invention, a known method can be used. For example, there is a method in which each component is mixed in a solution state and the solvent is evaporated or precipitated in the solvent. From an industrial point of view, a method of kneading each component in a molten state is preferred. For the melt kneading, kneading apparatuses such as a single-screw or twin-screw extruder and various kneaders which are generally used can be used. In particular, a biaxial high kneader is preferred. During the melt kneading, the cylinder set temperature of the kneading apparatus is 200
To 360 ° C, more preferably 230 ° C.
３５０350 ° C.

At the time of kneading, the respective components may be previously mixed uniformly using a device such as a tumbler or a Henschel mixer, or if necessary, the mixing may be omitted, and each component may be separately supplied to the kneading device. Methods can also be used.

In the liquid crystal polyester resin composition used in the present invention, an inorganic filler is used if desired.
Examples of such inorganic fillers include calcium carbonate, talc, clay, silica, magnesium carbonate, barium sulfate, titanium oxide, alumina, gypsum, glass flake, glass fiber, carbon fiber, alumina fiber, silica alumina fiber, and aluminum borate. Examples include whiskers and potassium titanate fibers.

The liquid crystal polyester resin composition used in the present invention may further contain, if necessary, an organic filler, an antioxidant, a heat stabilizer, a light stabilizer, a flame retardant, a lubricant, an antistatic agent,
Various additives such as rust inhibitor, crosslinking agent, foaming agent, fluorescent agent, surface smoothing agent, surface gloss improver, release improver such as fluororesin, etc.
It can be used as long as the physical properties of the polarizing film are not significantly impaired.

The method for forming the polarizing film comprising the liquid crystal polyester resin composition of the present invention is not particularly limited, and can be easily carried out by a known method. For example, a casting method in which the composition is dissolved in a solvent and then the solution is cast to form a film, a T-die method in which the molten resin is extruded and wound from a T-die, and a molten resin is cylindrically extruded from an extruder provided with an annular die. It can be extruded into a shape, cooled and wound by an inflation film forming method to obtain a polarizing film,
Alternatively, a polarizing film can be obtained by further uniaxially stretching a sheet obtained by an injection molding method or an extrusion method. In the case of injection molding, extrusion molding, or the like, a polarizing film can also be obtained by dry-blending component pellets at the time of molding and melt-molding them without going through a kneading step in advance.

When a polarizing film is obtained by the T-die method, it is usually obtained by winding a molten resin extruded through a T-type die (hereinafter sometimes referred to as a T-die) while stretching in the direction of the winder (longitudinal direction). A uniaxially stretched film or a biaxially stretched film is preferably used.

The conditions for setting the extruder when forming a uniaxially stretched film can be appropriately set according to the composition of the composition.
The cylinder set temperature is preferably in the range of 200 to 360 ° C, more preferably in the range of 230 to 350 ° C. If the ratio is outside this range, thermal decomposition of the composition may occur or film formation may be difficult, which is not preferable.

The slit interval of the T-die is 0.2 to 2.0.
mm is preferable, and 0.2 to 1.2 mm is more preferable.
The draft ratio of the uniaxially stretched film is preferably in the range of 1.1 to 40, more preferably 10 to 40, and particularly preferably 15 to 35.

The draft ratio referred to here is a value obtained by dividing the cross-sectional area of the T-die slit by the cross-sectional area of the film perpendicular to the longitudinal direction. If the draft ratio is less than 1.1, the film strength is insufficient, and if the draft ratio exceeds 45, the surface smoothness of the film may be insufficient, which is not preferable. The draft ratio can be set by controlling the setting conditions of the extruder, the winding speed, and the like.

For the biaxially stretched film, the same extruder setting conditions as those for forming the uniaxially stretched film, that is, the cylinder set temperature is preferably in the range of 200 to 360 ° C., more preferably 230 to 350 ° C. The composition is melt-extruded at a slit interval of preferably 0.2 to 1.2 mm, and the melt sheet extruded from the T-die is simultaneously stretched in the longitudinal direction and the direction perpendicular to the longitudinal direction (lateral direction). First, the melt sheet extruded from the T-die is stretched in the longitudinal direction, and then the stretched sheet is stretched in a transverse direction from the tenter at a high temperature of 100 to 300 ° C. in the same step. Can be

When a biaxially stretched film is obtained, the stretching ratio is preferably 1.2 to 20 times in the longitudinal direction and 1.2 to 20 times in the transverse direction. If the stretching ratio is out of the above range, the strength of the composition film may be insufficient, or it may be difficult to obtain a film having a uniform thickness, which is not preferable.

When a polarizing film is obtained by the inflation film forming method, the liquid crystal polyester resin composition obtained by the above method is supplied to a melt kneading extruder equipped with a die having an annular slit, and a cylinder set temperature of 200 to 36.
Melt kneading is performed at 0 ° C, preferably 230 to 350 ° C, and the molten resin is extruded upward or downward from the annular slit of the extruder. The annular slit interval is usually 0.1 to 5 mm, preferably 0.2 to 2 mm, and the diameter of the annular slit is usually 20 to 1000 mm, preferably 25.
６００600 mm.

The melt-extruded molten resin film is drafted in the longitudinal direction (MD), and air or an inert gas, for example, nitrogen gas, is blown from the inside of the cylindrical film, so that a transverse direction perpendicular to the longitudinal direction is obtained. The film is expanded and stretched in (TD).

In inflation molding (film formation),
The preferred blow ratio is 1.5 to 10, and the preferred MD draw ratio is 1.5 to 40. If the setting conditions during the inflation film formation are outside the above range, it may be difficult to obtain a high-strength liquid crystal polyester resin composition film having a uniform thickness and no wrinkles, which is not preferable.

The expanded film is air-cooled or water-cooled on its circumference, and then passed through a nip roll and taken out.

In the case of inflation film formation, conditions can be selected according to the composition of the liquid crystal polyester resin composition such that the cylindrical molten film expands to a uniform thickness and a smooth surface state.

The thickness of the film is not particularly limited, but is preferably 3 to 500 μm, more preferably 3 to 100 μm.
μm.

The light transmittance of the polarizing film of the present invention is preferably 8% or more when measured at a wavelength of 600 nm.
15% or more is more preferable. The degree of polarization of the polarizing film was 51% when measured at a wavelength of 600 nm.
Or more is preferable, and 61% or more is more preferable.

The polarizing film of the present invention can be dyed with iodine or a dichroic dye, if necessary. The dichroic dye can be selected according to the purpose from a conjunctive dye having acidic dichroism, an acid dye, a basic dye, a disperse dye, a mordant dye, etc. ,
As described in “Applications of Polarizing Films”, page 40 of CMC Co., Ltd., 1986, azo-based and anthraquinone-based disperse dyes, bisazo-type, trisazo-type direct dye-type dyes, and the like can be mentioned. Can be used alone or in combination of two or more. The amount of the iodine or dichroic dye can be used within a range that does not impair the properties of the polarizing film, but is preferably 20 parts by weight or less based on 100 parts by weight of the liquid crystal polyester resin composition. The iodine, dichroic dye, and the like can be used as a polarizing film when melt-kneaded or molded during liquid crystal polyester resin composition and finely dispersed in the liquid crystal polyester resin composition to be used as a polarizing film.

The polarizing film of the present invention can have a laminated structure of two or more layers of a liquid crystal polyester resin composition layer and a liquid crystal polyester or a thermoplastic resin layer other than the liquid crystal polyester resin composition. That is, as the polarizing film of the present invention, a laminate having at least a layer composed of the liquid crystal polyester resin composition and a layer composed of a thermoplastic resin (excluding the liquid crystal polyester and the liquid crystal polyester resin composition). A polarizing film composed of a structure is also used.

The thermoplastic resin mentioned here includes, for example, polyethylene, polypropylene, polyolefin such as ethylene-α-olefin copolymer, polystyrene,
Examples thereof include polyester such as polycarbonate, polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyphenylene ether, polyether sulfone, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyphenylene sulfide, and fluororesin. Among these, polyethylene, polypropylene, ethylene-α-
Olefin copolymers and polyethylene terephthalate are preferred. As the thermoplastic resin, one kind or a mixture of two or more kinds can be used. Further, as the thermoplastic resin, a thermoplastic resin modified by introducing a functional group into a molecular chain is also used.

If necessary, an adhesive layer, an adhesive resin layer, or an anchor coat agent layer between the layers may be provided between the layers. Examples of such an adhesive layer include a layer made of a hot melt adhesive, a polyurethane adhesive, a two-component polyester, and a layer made of an adhesive film.

The surface of the polarizing film of the present invention can be subjected to a surface treatment as required. Such surface treatment methods include, for example, corona discharge treatment, plasma treatment,
Examples include a flame treatment, a sputtering treatment, a solvent treatment, an infrared treatment, an ultraviolet treatment, a polishing treatment, and an ozone treatment. If necessary, a transparent conductive film such as an indium-tin oxide may be formed on the surface of the polarizing film by, for example, an evaporation method.

[0085]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples.

(1) Liquid Crystal Polyester of Component (A) (i) 8.3 kg (60 mol) of p-acetoxybenzoic acid, 2.49 kg (15 mol) of terephthalic acid, 0.83 kg (5 mol) of isophthalic acid and 4 5,45 kg (20.2 mol) of 4,4'-diacetoxydiphenyl was charged into a polymerization tank having a comb-shaped stirring blade, and the temperature was increased while stirring under a nitrogen gas atmosphere, and polymerization was performed at 330 ° C. for 1 hour. The acetic acid gas produced as a by-product during this period was polymerized under strong stirring while being liquefied and collected and removed by a cooling tube. Thereafter, the system was gradually cooled, and the polymer obtained at 200 ° C. was taken out of the system.
The obtained polymer was pulverized with a hammer mill manufactured by Hosokawa Micron Co., Ltd. to obtain particles of 2.5 mm or less. This is further heated at 280 ° C. in a rotary kiln under a nitrogen gas atmosphere.
For 3 hours to obtain a particulate wholly aromatic polyester having a flow temperature of 324 ° C. and comprising the following repeating structural units. Here, the flow temperature refers to a resin heated at a heating rate of 4 ° C./min using a Shimadzu Koka type flow tester model CFT-500 and a load of 100 kgf / c.
When extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm under m ² , this refers to a temperature at which the melt viscosity shows 48,000 poise. Hereinafter, the liquid crystal polyester is abbreviated as A-1. This polymer showed optical anisotropy at 340 ° C. or more under pressure. The repeating structural units of the liquid crystal polyester A-1 are as follows.

[0087]

(Ii) p-hydroxybenzoic acid 16.6k
g (12.1 mol), 8.4 kg (45 mol) of 6-hydroxy-2-naphthoic acid and 18.6 kg of acetic anhydride
(182 mol) was charged into a polymerization vessel equipped with a comb-shaped stirring blade, and the temperature was increased while stirring under a nitrogen gas atmosphere, and the polymerization was performed at 320 ° C. for 1 hour, and further at 320 ° C. for 1 hour under a reduced pressure of 2.0 torr. Was. During this time, acetic acid produced as a by-product was continuously distilled out of the system. Thereafter, the system was gradually cooled, and the polymer obtained at 180 ° C. was taken out of the system. The obtained polymer is pulverized in the same manner as in the above (A-1), and then treated in a rotary kiln under a nitrogen gas atmosphere at 240 ° C. for 5 hours, whereby the following repetitive particles having a flow temperature of 270 ° C. A unitary aromatic polyester was obtained.
Hereinafter, the liquid crystal polyester is abbreviated as A-2. This polymer showed optical anisotropy at 280 ° C. or more under pressure. The ratio of the repeating structural units of the liquid crystal polyester A-2 is as follows.

[0089]

(2) Copolymer of Component (B) In the following, E represents ethylene, MA represents methyl acrylate, and GMA represents glycidyl methacrylate.

(I) Esplen manufactured by Sumitomo Chemical Co., Ltd.
EMA 2752 MA / E / GMA = 59.0 / 38.7 / 3.2 weight ratio copolymer rubber, Mooney viscosity = 15 Here, the Mooney viscosity is 1 according to JIS K6300.
It is a value measured using a large rotor at 00 ° C. Hereinafter, the copolymer may be referred to as B-1.

(Ii) Oxazoline-styrene copolymer, manufactured by Nippon Shokubai Co., Ltd., RPS 1005 or less.
-2.

(3) Methods of measuring physical properties (i) Oxygen gas permeability: Measured at a temperature of 20 ° C. in accordance with JIS K7126 A method (differential pressure method). The unit is cc / m ² · 24 hr · 1 atm.

(Ii) Water vapor transmission rate: JIS Z0208
The measurement was performed under the conditions of a temperature of 40 ° C. and a relative humidity of 90% according to the (cup method). The unit is g / m ²・ 24hr ・ 1atm
It is. The oxygen gas permeability and the water vapor permeability were determined by converting the film thickness to 25 μm.

(Iii) Flex resistance: The laminated material was cut out in the MD and TD directions of the liquid crystal polyester resin composition layer,
MIT bending tester manufactured by Toyo Seiki Co., Ltd.
Folding Endurance Tester
Using the MIT-D type, a bending test was performed based on JIS-p-8115 at a load of 1 kgf, a bending angle of 135 degrees, a bending surface curvature radius of 1 mm, and a bending speed of 175 times / min. The number of bendings was determined.

(Iv) Light transmittance: U manufactured by Hitachi, Ltd.
-3500 type Using a self-recording spectrophotometer, transmittance (%)
I asked.

(V) Degree of polarization: U- manufactured by Hitachi, Ltd.
Using a 3500 type self-recording spectrophotometer, the transmittance at the parallel position of the two polarizing plates was Y ₁ , and the transmittance at the vertical position was Y _2, which was determined by the following equation.

Example 1 79% by weight of A-1 and 21% by weight of B-1 were melted at a cylinder set temperature of 350 ° C. and a screw rotation speed of 200 rpm using a TEX-30 type twin screw extruder manufactured by Nippon Steel Corporation. The composition was obtained by kneading. The pellets of this composition were fed to a 60 mmφ single screw extruder equipped with a cylindrical die, the cylinder set temperature was 350 ° C., and the screw rotation number was 9
The resin is melt-extruded at 0 rpm, and the molten resin is extruded upward from a cylindrical die having a die diameter of 50 mm, a lip interval of 1.0 mm, and a die setting temperature of 350 ° C. Expansion, blow ratio 2.
After cooling, it was wound through a nip roll at a winding speed of 50 m / min. The thickness of the obtained film was 7 μm. The light transmittance at a wavelength of 600 nm of the obtained film was 36%, and the degree of polarization at 600 nm was 74%. The bending test result of the film was 100,000 times or more. Oxygen permeability: 0.5cc /
m ² · atm · 24 h, water vapor transmission rate is 0.3 g / m ²
・ Atm ・ 24h.

Comparative Example 1 Melting and kneading of a resin and formation of a film were attempted in the same manner as in Example 1 except that B-1 was not used, but no good film was obtained.

Example 2 93% by weight of A-2 and 7% by weight of B-2 were mixed at a cylinder set temperature of 298 ° C. and a screw rotation speed of 180 rpm using a TEX-30 type twin screw extruder manufactured by Nippon Steel Corporation.
The melt kneading was performed at m. The obtained pellets are supplied to a single-screw extruder having a cylinder set temperature of 290 ° C. and a screw rotation speed of 90 rpm, and a die set temperature of 300 ° C., a die diameter of 50 mm, a lip interval of 1.0 mm, and a die set temperature of 3
The molten resin is extruded upward from a cylindrical die at a temperature of 03 ° C., and dry air is pressed into the hollow portion of the cylindrical film to expand the cylindrical film. The blow ratio is set to 3.1. The film was wound at 35 m / min to obtain a film. The thickness of the obtained film was 12 μm. The light transmittance at a wavelength of 600 nm of the film is 29%, 6
The degree of polarization at 00 nm was 68%. The bending test result of the film was 100,000 times or more. The oxygen permeability was 0.4 cc / m ² · atm · 24 h, and the water vapor permeability was 0.3 g / m ² · atm · 24 h.

Comparative Example 2 Melt kneading and film formation were attempted in the same manner as in Example 2 except that B-2 was not used, but no good film was obtained.

[0102]

The polarizing film obtained by the present invention is excellent in heat resistance, mechanical strength, gas barrier properties, etc., and has good polarizing properties, moldability, and flexibility, so that it can be used in personal computers, word processors and liquid crystal printers. It can be widely used for a display such as a liquid crystal television, or for a display for an in-vehicle instrument panel, a light control plate for an optical disk, an optical lens filter, a diffraction grating, and the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 67/03 C08L 67/03 G02F 1/1335 510 G02F 1/1335 510

Claims (17)

[Claims] 1. A liquid crystal polyester resin composition comprising (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase. Polarizing film. 2. A layer comprising a liquid crystal polyester resin composition comprising at least (A) a liquid crystal polyester as a continuous phase and (B) a copolymer having a functional group reactive with the liquid crystal polyester as a dispersed phase; A polarizing film comprising a laminated structure having a resin (excluding the liquid crystal polyester and the liquid crystal polyester resin composition). 3. A liquid crystal polyester resin composition comprising (A) 56.0 to 99.9% by weight of a liquid crystal polyester and (B) a copolymer having a functional group reactive with the liquid crystal polyester, 44.0 to 04.0%. 3. The polarizing film according to claim 1, which is a composition containing 0.1% by weight. 4. A liquid crystal polyester resin composition comprising (A) 56.0 to 99.9% by weight of a liquid crystal polyester and (B) a copolymer having a functional group having a reactivity with the liquid crystal polyester of 44.0 to 04.0%. 3. The polarizing film according to claim 1, which is a composition obtained by melt-kneading 1% by weight. 5. The polarizing film according to claim 1, wherein the functional group reactive with the liquid crystal polyester is an oxazolyl group, an epoxy group or an amino group. 6. The copolymer (B) having a functional group reactive with the liquid crystal polyester, wherein the copolymer (B) contains 0.1 to 30% by weight of an unsaturated glycidyl carboxylate unit and / or an unsaturated glycidyl ether unit. The polarizing film according to claim 1, wherein the polarizing film is a polymer. 7. The copolymer (B) having a functional group reactive with a liquid crystal polyester has a crystal heat of fusion of 3 J / g.
The polarizing film according to any one of claims 1 to 6, wherein the copolymer is a copolymer having a molecular weight of less than or equal to. 8. The method according to claim 1, wherein the Mooney viscosity of the copolymer (B) having a functional group reactive with the liquid crystal polyester is in the range of 3 to 70. Polarizing film. The Mooney viscosity referred to here is JI
A value measured using a large rotor at 100 ° C. according to SK6300. 9. The polarizing film according to claim 1, wherein the copolymer (B) having a functional group reactive with the liquid crystal polyester is a rubber having an epoxy group. 10. The rubber having an epoxy group comprises (meth) acrylate-ethylene- (unsaturated carboxylic acid glycidyl ester and / or unsaturated glycidyl ether) copolymer rubber. The polarizing film as described in the above. 11. A rubber having an epoxy group, wherein the (meth) acrylate unit is more than 40% by weight and less than 97% by weight, the ethylene unit is 3% by weight or more and less than 50% by weight, the unsaturated glycidyl ester unit is The polarizing film according to claim 9, wherein the copolymer is a copolymer having 0.1 to 30% by weight of unsaturated glycidyl ether units. 12. The method according to claim 12, wherein the (meth) acrylate is methyl acrylate, methyl methacrylate, n-butyl acrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate,
The polarizing film according to claim 10 or 11, comprising at least one selected from -ethylhexyl acrylate and 2-ethylhexyl methacrylate. 13. The polarized light according to claim 1, wherein the copolymer (B) having a functional group reactive with the liquid crystal polyester is a thermoplastic resin having an epoxy group. the film. 14. A thermoplastic resin having an epoxy group,
(A) 50 to 99% by weight of ethylene units, (b) 0.1 to 30% by weight of unsaturated glycidyl ester units and / or unsaturated glycidyl ether units.
(C) 0-50 ethylenically unsaturated ester compound units
14. The polarizing film according to claim 13, which is an epoxy group-containing ethylene copolymer in an amount of 10% by weight. 15. The polarizing film according to claim 1, wherein the liquid crystal polyester (A) contains at least 30 mol% of the following repeating structural units. 16. The liquid crystal polyester (A) according to claim 1, which is obtained by reacting an aromatic dicarboxylic acid, an aromatic diol and an aromatic hydroxycarboxylic acid. The polarizing film as described in the above. 17. The polarizing film according to claim 1, wherein the liquid crystal polyester (A) is obtained by reacting a combination of different kinds of aromatic hydroxycarboxylic acids.