JPH0822568B2 - Film and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a film and a method for producing the same, and more specifically, a film having further improved performance of a liquid crystalline polymer film and excellent physical properties and a method for producing the same. Regarding

[Problems to be Solved by Conventional Techniques and Inventions] Liquid crystalline polymers are excellent in heat resistance, dimensional stability, and mechanical strength. However, in the film forming process, the high degree of orientation of the molecular chains, which is a characteristic of the liquid crystalline polymer, makes it extremely difficult to perform melt extrusion molding, has a good appearance and thickness accuracy, and is well balanced. A film having mechanical properties and usable for practical use has not yet been obtained. In particular, since the molecular chains are highly oriented, the anisotropy is strong, the strength in the width direction of the film is extremely low, and the tear resistance is poor.

Therefore, conventionally, liquid crystal polymer films or sheets with reduced anisotropy and methods for producing them have been proposed, but it is difficult to industrially produce a uniform film having excellent properties with good reproducibility. . For example, JP-A-55-
Japanese Patent No. 161821 discloses a method for producing a high degree of polymerization polyester having a p-oxybenzoic acid residue, a hydroquinone residue, and an isophthalic acid residue as constituent components.
Japanese Patent Laid-Open No. 26-26727 and Japanese Patent Laid-Open No. 56-46727 disclose a polyester film having the same components as described above and a method for producing the same. In each of these techniques, the anisotropy is reduced by plasticizing the liquid crystalline polymer itself as a raw material. However, these films and the like have a problem that the reduction of anisotropy is extremely large and the strength originally possessed by the liquid crystalline polymer is sacrificed.

Further, as a method for obtaining a film having no anisotropy while maintaining the original strength of the liquid crystalline polymer, JP-A-52-1095
Japanese Patent Laid-Open No. 78 proposes a multiaxially oriented laminated film in which a plurality of films in which a liquid crystalline polymer is uniaxially oriented are crossed at an angle of 30 ° or more and laminated. However,
Since the orientation direction of the film produced by the conventional extrusion molding method coincides with the take-up direction of the film, it is difficult to laminate the orientation directions of a plurality of films while intersecting them at a constant angle in a continuous process. In particular, it is extremely difficult to industrially continuously produce long products and thin products, and it is not economical, which is not satisfactory as an industrial production method.

Also, improvement of the extruder is being studied.
For example, in JP-A-58-59818, in order to reduce the anisotropy of the film by generating a turbulent flow in the die to disturb the orientation, a heatable plate-shaped porous body is provided inside the die. The method of setting is proposed. However, in this method, not only the apparatus becomes very complicated, but also according to experiments, since the share rate in the porous body inside the die is too high, the workability and the operability are remarkably poor, and it is industrially difficult. Not a practical method.

On the other hand, as a method for limiting the tearing strength by limiting the molding conditions, JP-A-56-467287 discloses an inflation method in which the draw ratio of the film in the take-up direction is 2%.
A method for producing a biaxially oriented film has been proposed in which the stretching ratio is ˜50 times and the draw ratio in the width direction is 1.2 to 20 times. However, in this method, if the stretching ratio in the width direction is increased in order to obtain sufficient strength in the width direction, not only the accuracy of the thickness of the film is lowered, but also the film is torn at the time of blowing and the work and the operation are performed. There is a problem that the sex is not sufficient.

An object of the present invention is to provide a film that retains the inherent strength of a polymer even if it is a liquid crystalline polymer, is excellent in tear resistance, etc. and can be put to practical use.

Another object of the present invention is to obtain a film that retains the inherent strength of the polymer even if it is a liquid crystalline polymer, is excellent in tear resistance, and can be put to practical use in a continuous process industrially and economically. It is to provide a method for producing a film that can be formed.

[Structure of the Invention] As a result of intensive studies, the present inventors have found that the above object can be achieved by a film composed of a specific thermotropic liquid crystal polymer and having a specific alignment structure, and have reached the present invention.

That is, the present invention is a polymer fill formed by melt extrusion from a T-die by one extruder, wherein the film comprises an aromatic polyester, an aromatic polythiol ester, an aromatic polyazomethine and an aromatic polyester carbonate. The film is composed of at least one thermotropic liquid crystal polymer selected from the group, the polymer of the film is oriented in the extrusion direction, and the polymer of at least one of the front and back layer parts of the film is The above problem is solved by a film oriented in a direction orthogonal to the direction.

According to the film having the above structure, the specific thermotropic liquid crystal polymer is oriented in the extrusion direction, and the polymer is oriented in at least one of the front and back layer portions of the film, and is continuously oriented in a direction different from the extrusion direction. Therefore, there is no anisotropy, and the original strength of the polymer can be exhibited not only in the extrusion direction but also in the direction orthogonal to the extrusion direction.

The present invention also provides a polymer film composed of at least one thermotropic liquid crystal polymer selected from the group consisting of aromatic polyesters, aromatic polythiol esters, aromatic polyazomethines and aromatic polyester carbonates, in a single extrusion. A method for producing a film by melt-extruding from a slit of a T-die by a machine, in which a polymer of at least one of the front and back layer portions of the molten polymer is orthogonal to the extrusion direction in the slit portion of the T-die. While applying shear stress to the
The above problem is solved by a method for producing a film which is melt-extruded at a temperature of 0 to 400 ° C.

According to the method for producing a film having the above-described configuration, in the slit portion of the T-die, shear stress is applied to the polymer of at least one of the front and back layer portions of the specific liquid crystalline molten polymer in the rotational direction orthogonal to the extrusion direction. Since the polymer acts on at least one of the front and back layer portions of the film, the polymer can be oriented in a direction different from the extrusion direction.

In the present specification, the liquid crystalline polymer means a thermotropic liquid crystal polymer composition which exhibits an anisotropic melt phase which is softened and flowable by heating to be moldable and has birefringence when melted.

The term “film” is used to include all relatively thin and substantially flat structures that are sometimes referred to in the art as sheets, slabs, and the like.

The film of the present invention is composed of at least one thermotropic liquid crystalline polymer selected from the group consisting of aromatic polyesters, aromatic polythiol esters, aromatic polyazomethines and aromatic polyester carbonates.

Examples of the above liquid crystalline polymer include polymers composed of the following constituent components and the like.

(1) One or more kinds of aromatic dicarboxylic acids and alicyclic dicarboxylic acids (2) One or more kinds of aromatic diols, alicyclic diols and aliphatic diols (3) One kind of aromatic hydroxycarboxylic acids Or two or more kinds (4) one or more kinds of aromatic thiolcarboxylic acid (5) one or more kinds of aromatic dithiol and aromatic thiolphenol, as the liquid crystalline polymer comprising the above-mentioned constituent part, i) constituent component Polyester consisting of (1) and (2) ii) Polyester consisting of constituent component (3) iii) Polyester consisting of constituent components (1), (2) and (3) iv) Polythiol consisting of constituent component (4) Ester v) Polythiol ester composed of constituents (1) and (5) vi) Polythiol ester composed of constituents (1), (4) and (5) viii) constituent It is selected as a combination of polyesteramides and the like consisting of (1), (2), (3) and (5).

Further, although not included in the category of the combination of the above components, such liquid crystalline polymer includes aromatic polyazomethine, and specific examples thereof include poly (nitrilo-3-methyl-1,4).
-Phenylene nitriloethylidyne-1,4-phenylenerreridine), poly (nitrilo-2-methyl-1,4-phenylene nitrilomethylidine-1,4-phenylene methylidine), and poly (nitrilo-2-chloro- 1,4-phenylene nitrilomethylidine-1,4-phenylene methylidine) and the like.

Further, although not included in the above combination of components, the liquid crystalline polymer includes polyester carbonate. This is essentially a 4-oxybenzoyl unit,
Some are composed of dioxyphenyl units, dioxycarbonyl units and terephthaloyl units.

The aromatic zircaponic acid, terephthalic acid, 4,
4'-diphenyldicarboxylic acid, 4,4 "-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, diphenylether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane −4,4 ′
-Dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenyl ether 3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, Aromatic dicarboxylic acids such as naphthalene-1,6-dicarboxylic acid,
Alternatively, alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids such as chloroterephthalic acid, dichloroterephthalic acid, vorimoterephthalic acid, methylterephthalic acid, dimethylterephthalic acid, ethylterephthalic acid, methoxyterephthalic acid and ethoxyterephthalic acid. Is mentioned.

Examples of the alicyclic dicarboxylic acid include trans-1,4-cyclohexanedicarboxylic acid, cis-1,4-cyclohexanedicarboxylic acid, alicyclic dicarboxylic acid such as 1,3-cyclohexanedicarboxylic acid, or trans-1,4- (1-Methyl) cyclohexanedicarboxylic acid, trans-1,4-
Examples thereof include alkyl-, alkoxy- or halogen-substituted products of the alicyclic dicarboxylic acids such as (1-chloro) cyclohexanedicarboxylic acid.

Aromatic diols include hydroquinone, resorcin, 4,4'-dihydroxydiphenyl, 4,4 "-hydroxytriphenyl, 2,6-naphthalenediol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane. , 3,3'-dihydroxydiphenyl, 3,3'-dihydroxydiphenyl ether, 1,6-naphthalene diol, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl)
Alkyl, alkoxy or halogen substitution of aromatic diols such as methane or the above aromatic diols such as chlorohydroquinone, methylhydroquinone, 1-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcin, 4-methylresorcin The body etc. are mentioned.

Examples of the aliphatic diol include trans-1,4-cyclohexanediol, cis-1,4-cyclohexanediol, trans-1,4-cyclohexanedimethanol, trans-1,3-cyclohexanediol and cis-1,2-cyclohexane. Aliphatic diol such as diol, trans-1,3-cyclohexanedimethanol, or the above alicyclic diol such as trans-1,4- (1-methyl) cyclohexanediol, trans-1,4- (1-chloro) cyclohexanediol Examples thereof include alkyl-, alkoxy- or halogen-substituted compounds of cyclic diols.

Aliphatic diols include ethylene glycol, 1,3
Examples thereof include linear or branched aliphatic diols such as propanediol, 1,4-butanediol and neopentyl glycol.

Examples of the aromatic hydroxycarboxylic acid include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid, or 3-methyl- Four
-Hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid , 6-hydroxy-
5-ethyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 3-chloro-4-hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid,
3,5-Dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy Examples thereof include alkyl, alkoxy or halogen substitution products of aromatic hydroxycarboxylic acids such as -7-chloro-2-naphthoic acid and -hydroxy-5,7-dichloro-2-naphthoic acid.

Examples of the aromatic mercaptocarboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

Aromatic dithiyl, benzene-1,4-dithiol, benzene-1,3-dithiol, naphthalene-2,6-
Examples thereof include dithiol and naphthalene-2,7-dithiol.

Examples of the aromatic mercaptophenol include 4-mercaptophenol, 3-mercaptophenol, 2-mercaptophenol and the like.

The polymers i) to vii composed of the above constituents
Regarding i), depending on the constituent components, the composition ratio in the polymer, and the sequence distribution, there are some that do not have birefringence when melted, but the polymers used in the present invention are those that exhibit an anisotropic melt phase among the above polymers. Limited to

The liquid crystalline polymer used in the present invention can be produced by a known method.

Fully aromatic polymers suitable for use in the present invention include
It tends to be substantially insoluble in common solvents, and therefore
Not suitable for solution processing. However, as already mentioned, these polymers can be easily processed by conventional melt processing methods. Particularly preferred wholly aromatic polymers are somewhat soluble in pentafluorophenol.

The wholly aromatic polyester preferably used in the present invention may have an appropriate molecular weight, but generally has a weight average molecular weight of about 2,000 to 200,000, preferably about 10,000 to 50,00.
0, particularly preferably about 20,000 to 25,000. The molecular weight can be measured by gel permeation chromatography and other standard measuring methods without melt formation of the polymer, for example, by quantifying the end groups of a compression-molded film by infrared spectroscopy. It is also possible to measure the molecular weight using a light scattering method in a pentafluorophenol solution.

A polyester which forms a particularly preferred anisotropic melt phase has a naphthalene moiety-containing unit such as 6-hydroxy-2-naphthoyl, 2,6-dihydroxynaphthalene and 2,6-dicarboxynaphthalene in an amount of about 10 mol% or more. It is contained. Specifically, it is as follows.

(1) A polyester essentially consisting of the following repeating units I and II; The polyester contains about 10-90 mol% units I and about 10-90 mol% units II. In one embodiment, unit I is present in an amount of about 65-85 mol% (eg, about 75 mol%). In another embodiment, the unit II is about 15-35 mol%,
It is preferably present in a low concentration amount of about 20-30 mol%. At least a part of the hydrogen atoms bonded to the ring may be an alkoxy group having 1 to 4 carbon atoms, a halogen atom,
It may be substituted with a substituent selected from the group consisting of a phenyl group, a substituted phenyl group and combinations thereof.

(2) A polyester consisting essentially of the following repeating units II, III and IV; This polyester contains about 30 to 70 mol% of units II. This polyester preferably contains from about 40 units II to
60 mol%, about 20-30 mol% of unit III and about 20 unit IV
Contains ~ 30 mol%. Further, at least a part of the hydrogen atoms engaged with the ring may be a substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group and a combination thereof. May be substituted by.

(3) A polyester consisting essentially of the following repeating units II, IV, V and VI; (In the formula, R means a methyl group, chloro, bromo or a combination thereof, and is a substituent for a hydrogen atom on an aromatic ring.) This polyester contains about 20 to 60 mol% of the unit II,
IV about 5 to 35 mol%, unit V about 5 to 18 mol% and unit
It contains about 20-40 mol% VI. The polyether preferably contains about 35 to 45 mol% of the unit II, about 15 to 25 mol% of the unit IV, about 10 to 15 mol% of the unit V and about 25 to 35 mol% of the unit VI. However, the units IV and V and the total molar concentration are the units
Substantially equal to the molarity of VI. At least some of the hydrogen atoms bonded to the ring may have 1 carbon atom depending on the case.
It may be substituted with a substituent selected from the group consisting of an alkyl group having 4 to 4, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group and combinations thereof. This fully aromatic polyester has a temperature of 60
When dissolved in pentafluorophenol at a concentration of 0.3 W / V% at 0 ° C., it generally exhibits an inherent viscosity of at least 2.0 dl / g, for example 2.0 to 10.0 dl / g.

(4) A polyester consisting essentially of the following repeating units I, II, VII and VIII: A dioxyaryl unit represented by the general formula O-Ar-O VII (wherein Ar represents a divalent group containing at least one aromatic ring). (Wherein Ar is the same as above), and the polyester has a unit I of about 20 to 40 mol%.
II more than 10 mol% and about 50 mol% or less, unit VII more than 5 mol% and about 30 mol% or less, and unit VIII 5 mol%
Content of less than about 30 mol%. The polyester preferably has units I of about 20-30 mol%, for example about 25 mol%, units II of about 25-40 mol%, for example about 25 mol%.
35 mol%, about 15 to 25 mol% of unit VII, for example about 20 mol%, and about 15 to 25 mol% of unit VIII, for example about 20 mol. Further, at least a part of hydrogen atoms engaged with the ring may be an alkyl group having 1 to 4 carbon atoms,
It may be substituted with a substituent selected from the group consisting of an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a phenyl group, a substituted phenyl group and combinations thereof.

Units VII and VIII have 1 or 2 divalent bonds connecting these units to the other units on either side of the polymer backbone.
It is preferable that they are symmetrical in the sense that they are symmetrically arranged on the aromatic ring (for example, when they are present on the naphthalene ring, they are arranged in the para position or on the diagonal ring). . However, asymmetric units such as those derived from resorcinol and isophthalic acid can also be used.

Preferred dioxyaryl units VII are And the preferred dicarboxyaryl unit VIII is Is.

(5) Polyester consisting essentially of the following repeating units I, VII and VIII; A dioxyaryl unit represented by the general formula O-Ar-O VII (wherein Ar is as defined above). (Wherein Ar is the same as the above), and the unit is about 10 to 90 mol% of the unit I.
It contains 5 to 45 mol% VII and 5 to 45 mol% of unit VII. This polyester preferably contains about 20 units I.
-80 mol%, about 10-40 mol% of unit VII and about 10-40 mol% of unit VIII. More preferably, the polyester comprises about 60-80 mol% of unit I, about 10-20 mol%.
Unit VII and about 10 to 20 mol% of unit VIII. Further, at least a part of hydrogen atoms bonded to the ring may be an alkyl group having 1 to 4 carbon atoms, or 1 carbon atom depending on the case.
It may be substituted with a substituent selected from the group consisting of an alkoxy group of 4 to 4, a halogen atom, a phenyl group, a substituted phenyl group and a combination thereof.

Preferred dioxyaryl units VII are And a preferred dicarboxyaryl unit VIII is Is.

Further, in the polymer forming the anisotropic melt phase of the present invention, a part of one polymer chain is composed of the segments of the polymer forming the anisotropic melt phase described above,
Also included are polymers whose balance consists of segments of thermoplastic resin that do not form an anisotropic melt phase.

The melt-processable polymer composition that forms the anisotropic melt phase used in the present invention includes other polymers that form the anisotropic melt phase, thermoplastic resins that do not form the anisotropic melt phase, and thermosetting resins. It may contain one or more of a resin, a low molecular weight organic compound, and an inorganic substance. The polymer forming the anisotropic molten phase in the composition and the remaining portion may be thermodynamically compatible with each other. As the thermoplastic resin, for example, polyethylene, polypropylene, polybutylene, polybutadiene, polyisoprene, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic resin, ABS resin, AS resin, BS resin, polyurethane, silicone Resin, fluororesin, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, aromatic polyester, polyamide, polyacrylonitrile, polyvinyl alcohol, polyvinyl ether, polyetherimide, polyamideimide, polyetheretherimide, polyetheretherketone, polyether Sulfone, polysulfone, polyphenylene sulfide,
Polyphenylene oxide and the like are included.

Examples of the thermosetting resin include phenol resin, epoxy resin, melamine resin, urea resin, unsaturated polyester resin, alkyd resin and the like.

Examples of the low molecular weight organic compound include, for example, substances usually added to thermoplastic resins and thermosetting resins, that is, plasticizers, weathering / light resistance stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, Flame retardants, colorants such as dyes and pigments,
Further, a foaming agent, a divinyl compound, a crosslinking agent such as a peroxide or a vulcanizing agent, and a low molecular weight organic compound used as a lubricant for improving fluidity and releasability are included. Further, as the above-mentioned inorganic substances, for example, substances usually added to thermoplastic resins and thermosetting resins, namely, glass fibers, carbon fibers, metal fibers, ceramic fibers, boron fibers, general inorganic fibers such as asbestos, calcium carbonate. , Highly disperse silica, alumina, aluminum hydroxide, talc powder, mica, glass flakes, glass beads, quartz powder, silica sand,
Various metal powders, powdered substances such as carbon black, barium sulfate and calcined gypsum, inorganic compounds such as silicon carbonate, boron nitrite and silicon nitride, whiskers and metal whiskers are included.

The polymer film of the present invention is formed by the T-die method, and the polymer constituting the film is oriented in the extrusion direction. The T-die method is a method for producing a film by melt-extruding a polymer having a film-forming ability such as a liquid crystalline polymer with an extruder and extruding the melted polymer through a slit of a T-die connected to the extruder. A molten polymer, especially a liquid crystal polymer having a high orientation, is oriented in the extrusion direction as it is extruded.

Then, in order to eliminate the anisotropy of the liquid crystalline polymer and develop the large mechanical strength originally possessed by the polymer, the polymer of at least one of the front and back layer portions of the film is oriented in a direction orthogonal to the extrusion direction. are doing. It suffices that the polymer of at least one of the front and back layers of the polymer constituting the film is oriented, and is not limited to the front and back layer portions of the film, except for the polymer oriented in the extrusion direction, the polymer throughout the film. May be oriented in a direction orthogonal to the extrusion direction.

As described above, at least the surface layer portion of the film and / or
Alternatively, since the polymer of the back layer is oriented in the direction orthogonal to the extrusion direction, even a film made of a liquid crystalline polymer has no anisotropy and has a high tear resistance.

The film of the present invention can be manufactured as follows. That is, when melt-extruding a polymer film from a T-die connected to one extruder, at a slit portion, the polymer in at least one of the front and back layer portions of the molten polymer is applied in a direction orthogonal to the extrusion direction. A shear stress may be applied.

The method for producing the film of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of a T die connected to an extruder, and FIG. 2 is a transverse sectional view of the T die shown in FIG.

The die body (2) forming the T-die (1) is provided with a manifold (3) to which molten resin extruded in a molten state from a melt extrusion mechanism (not shown) of an extruder (not shown) is supplied. The manifold (3) is formed and extends to the slit (4) which is the discharge port of the molten polymer, and forms the lip at the tip of the T die (1).

Then, on both sides of the slit (4), there is provided a rotating means (5) which is in contact with the molten polymer and exerts shear stress in a direction orthogonal to the extrusion direction of the molten polymer. More specifically, as shown in FIG. 2, the rotating means (5) is composed of an endless belt (6) which can rotate at the tip of the T die (1). A slit (4) is formed by the opposing inner surfaces of (6). On both sides of the die side plate (8), a rotary drive shaft (7) slidingly contacting the endless belt (6) in a tensioned state to transmit a rotational force, and a rotary drive source for rotating the rotary drive shaft (7). (Not shown) are provided.

According to the film manufacturing apparatus having the above structure, since the rotational force of the rotary drive source can be transmitted to the endless belt (6) via the rotary drive shaft (7), the direction of extrusion to the molten polymer in the slit (4) part Shear stress can be applied in the orthogonal direction.

The rotating means (5) is not limited to the endless belt (6), and any means may be used as long as it makes contact with the molten polymer and exerts a shear stress in the above direction.

The extruder for melt extrusion molding is not particularly limited, but a conventionally known extruder used for extrusion molding of thermoplastic resin is preferably used.

In the above film manufacturing apparatus, tooth-shaped uneven portions may be formed on the outer surface of the endless belt (6). In this case, the endless belt (6) is disposed on the side of the rotary drive shaft (7). The endless belt (6) may be rotated in a predetermined direction by a rotary drive shaft having a gear that meshes with the uneven portion of (6) and a rotary drive source that rotates the rotary drive shaft having the gear. .

FIG. 3 is a cross-sectional view showing another embodiment of the T-die in the film manufacturing apparatus of the present invention, in which the die body (12) forming the T-die (11) has a manifold formed in the same manner as above. ing. Further, in this example, the slit (14) portion is formed by the facing surfaces of the pair of endless belts (16a) (16b), and each endless belt (16a) (16b)
Is a rotary drive source (not shown) via rotary drive shafts (17a) and (17b) provided on both sides of the die side plate (18), respectively.
Is rotated by.

According to the film manufacturing apparatus having the above configuration, the slit (1
Since the portion 4) is formed by the facing surfaces of the endless belts (16a) and (16b) that do not come into sliding contact with the rotary drive shafts (17a) and (17b), the film manufacturing apparatus shown in FIGS. Therefore, the slit (14) can be formed with higher accuracy. Also, a pair of endless belts (16a) (1
By rotating at least one of the endless belts in 6b), shear stress acts on the polymer in at least one of the front and back layers of the molten polymer in the slit (14) in the direction orthogonal to the extrusion direction. Can be made. A pair of endless belts (16a) (16b)
May rotate in the same direction or may rotate in different directions.

In addition, in the film manufacturing apparatus shown in FIG. 3, the pair of endless belts (16a) and (16b) is not always necessary, and at least one endless belt may be provided.

Also, in order to prevent the molten orimer from leaking to the side of the T-die (1) (11) due to the rotation of the endless belts (6) (16a) (16b), both sides of the T-die (1) (11) are prevented. A seal member may be provided in the.

The shape and structure of the T-die (1) (11) are not particularly limited, and the T-die (1) (11) has a rotating means such as an endless belt that rotates in a direction orthogonal to the extrusion direction in the molten polymer of the slits (6) (16a) (16b). If you have.

The action region where the rotational shearing force is applied by the endless belt is not limited to the tip end portion of the T die, and may be a region in which the polymer of the front and back layer portions of the obtained film can be oriented in a direction different from the extrusion direction, but is preferable. Is the tip of the T-die,
More preferably, the area is 10 to 150 mm from the tip of the lip. The preferable width of the endless belt is about 10 to 80 mm.

A drive mechanism such as a rotary drive shaft for driving the endless belt may be provided on both sides of the T-die as shown in the drawing, but is preferably provided inside the T-die.

The extrusion molding temperature of the liquid crystalline polymer is equal to or higher than the flow starting temperature of the polymer. The extrusion molding temperature in the first half is 200-400 ℃
The temperature is preferably 260-330 ° C. The flow starting temperature mentioned here is the lowest temperature at which the liquid crystalline polymer can be melted and flowed.

Further, it is preferable that a temperature controller for the endless belt is provided. When controlling the temperature of the endless belt, the preferred temperature of the endless belt is -10 ℃ + 20 ℃ of the resin temperature
Degree, more preferably +5 to + 10 ° C of resin temperature
Is. In addition, as a method of the temperature control device, various heating temperature control methods such as a heater are adopted and are not particularly limited.

The material of the endless belt may be a metal used for a general T-die and a metal belt, and may be a metal having heat resistance and corrosion resistance as necessary, but is not limited to the metal. Absent.

The process of forming a liquid crystalline polymer film having preferable properties by the above film manufacturing apparatus will be described below.

The endless belt can rotate in a film extrusion direction, that is, a direction orthogonal to the take-up direction. When the liquid crystalline polymer melt passes through the endless belt, the shear stress generated by the rotation of the endless belt causes a flow in the liquid crystalline polymer melt in a direction orthogonal to the film take-up direction, causing the liquid crystalline polymer to pull. A continuous layer is formed which is oriented in a direction orthogonal to the take direction.
Then, since the liquid crystalline polymer flows in the ejection direction, that is, in the extrusion direction in the T-die, the molecular chains are oriented in the film taking direction, and in addition to the orientation of the molecular chains,
The action of the endless belt induces the orientation of the molecular chains in the direction orthogonal to the film take-up direction. Therefore,
It is presumed that the liquid crystalline polymer film obtained by the present invention has molecular chains biaxially oriented in each direction in the film plane, isotropic in physical properties and excellent in tear resistance.

The ratio of the share rate between the film take-up direction and the direction orthogonal to the direction is not particularly limited and can be appropriately set according to the desired characteristics of the film, but is 1.0: 0.2 to 5.0. Preferably. The rotation speed of the endless belt can be appropriately set according to the desired properties of the film. Also, by controlling the flow rate (extrusion rate) of the liquid crystalline polymer in the die and the slit gap, the shear stress in each direction can be changed, and the orientation direction of the polymer that constitutes the film can be changed to the desired direction. Can be set. Flow rate of liquid crystalline polymer in die (extrusion rate)
The gap between the slits and slits can be freely selected according to the desired properties of the film and is not particularly limited.

Further, the polymer film extruded as described above is a conventionally used stretching method, for example, a tenter method,
It may be uniaxially stretched or biaxially stretched by a multistage stretching method or the like. If necessary, surface treatment such as corona discharge treatment or heat treatment may be performed.

In the above film, the thickness and width of the film are not particularly limited.

The liquid crystalline polymer film of the present invention has high strength and high elastic modulus, is excellent in heat resistance, chemical stability, electrical properties, dimensional stability, gas barrier properties, etc., and is a drawback of conventional liquid crystalline polymer films. There is no extreme anisotropy, and the mechanical properties are balanced, and the tear resistance is significantly improved. Further, even a liquid crystalline polymer film has good appearance and thickness accuracy, and also has good workability and operability during extrusion molding and is suitable for an industrial production method. Such a film of the present invention is a video tape, a cassette tape,
It can be preferably used for floppy disks, flexible printed boards, speaker diaphragms, capacitor derivatives, electric-related applications such as electric motor dielectric films, microfilms, thermal transfer printer tapes, movie films, packaging materials, sheet molding materials and the like.

[Effect of the Invention] As described above, according to the film of the present invention, the film is composed of a specific thermotropic liquid crystal polymer, the polymer of the film is oriented in the extrusion direction, and the front and back layer parts of the film are The polymer of at least one of the layers is oriented in a direction orthogonal to the extrusion direction, so that even if it is a liquid crystalline polymer, it retains the inherent strength of the polymer and is excellent in tear resistance, etc. It has excellent characteristics.

Further, according to the method for producing a film of the present invention, in the slit portion of the T die of one extruder, the polymer in at least one of the front and back layer portions of the specific liquid crystalline molten polymer is orthogonal to the extrusion direction. Since the melt extrusion is carried out at a specific temperature while applying a shearing stress in the direction of rotation, it is possible to industrially and economically obtain a film having the above-mentioned excellent properties and practically applicable in a continuous process.

[Examples] Hereinafter, the present invention will be described in more detail based on Examples.

Example T shown in FIGS. 1 and 2 as a film manufacturing apparatus
A die was used. 150 pellets of liquid crystalline polymer (product name: Vectra A900 manufactured by Polyplastics Co., Ltd.) in advance
It was dried at a temperature of ° C. for 8 hours. Then, as the T die, a die having a slit width of 400 mm, a lip gap of 0.3 mm, and a metal endless belt having a width of 30 mm at a position 30 mm from the tip of the lip was used and extruded at a temperature of 280 ° C. At that time, the endless belt was rotated at a speed of 4 m / min by the rotary drive shaft, and the film was taken at a speed of 8 m / min. The resulting film in the direction orthogonal to the take-up direction and take-up direction tensile strength respectively 3850kg / cm ^2, was 3300 kg / cm ^2, with an excellent tear resistance, as the transparent surface good smooth and shiny Met.

Comparative Example The liquid crystal polymer used in the examples was extruded from a conventional T-die at a temperature of 280 ° C., and the film was pulled at a speed of 12 m / min. The pulling direction of the obtained film and the tensile strength in the direction orthogonal to the pulling direction are respectively 4650 kg / c.
The film had m ² of 165 kg / cm ² and was poor in tear resistance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing an embodiment of a T die connected to an extruder, FIG. 2 is a transverse sectional view of the T die shown in FIG. 1, and FIG. It is sectional drawing which shows the other embodiment of T die in the film manufacturing apparatus of invention. (1) (11) …… T die, (4) (14) …… slit, (5) …… rotating means, (6) (16a) (16b) …… endless belt

Claims (2)

[Claims] 1. A polymer film formed by melt extrusion from a T-die by a single extruder, wherein the film comprises an aromatic polyester, an aromatic polythiol ester, an aromatic polyazomethine and an aromatic polyester carbonate. Which is composed of at least one type of thermotropic liquid crystal polymer selected from the above, the polymer of the film is oriented in the extrusion direction, and the polymer of at least one of the front and back layer portions of the film is A film which is oriented in a direction orthogonal to the film. 2. A polymer film composed of at least one thermotropic liquid crystal polymer selected from the group consisting of aromatic polyesters, aromatic polythiol esters, aromatic polyazomethines and aromatic polyester carbonates is extruded in a single unit. A method for producing a film by melt-extruding from a slit of a T-die by a machine, in which a polymer of at least one of the front and back layer portions of the molten polymer is orthogonal to the extrusion direction in the slit portion of the T-die. 200 to 400 while applying shear stress to
A method for producing a film, which comprises melt-extruding at a temperature of ° C.