JP2776536B2 - Method for producing liquid crystalline polymer film - Google Patents

Description

The present invention relates to a method for producing a thermotropic liquid crystalline polymer (hereinafter referred to as a liquid crystalline polymer) film capable of forming an anisotropic molten phase upon thermal melting. More specifically, the present invention relates to a method for producing a liquid crystal polymer film having excellent physical properties, which further improves the performance of a conventional liquid crystal polymer film.

(B) Conventional technology In recent years, high-strength films, high-elastic films, flexible films, adhesive films, transparent films, conductive films, light-shielding films, gas-barrier films, heat-resistant films, and chemical-resistant films have been developed from various polymers. Various films such as a conductive film and a film obtained by combining them have been developed and used for various purposes.

Liquid crystalline polymers have excellent mechanical properties, dimensional stability, heat resistance, chemical stability, gas barrier properties, and good electrical properties. Attention has been paid to polymers, and various development studies are being conducted in various fields. However, in film forming, Japanese Patent Publication No. 60-42287 discloses a method of forming a liquid crystalline polymer into a film while drafting it, utilizing the high degree of molecular chain orientation, which is a characteristic of liquid crystalline polymers, and then separating the fibers. In order to use a liquid crystalline polymer as a film, the high degree of orientation of the molecular chains of the liquid crystalline polymer suffers and the width direction of the film (hereinafter referred to as the (Extremely weak in the TD direction), which makes melt extrusion extremely difficult.

Various methods have been studied to solve the problem that the strength of the liquid crystal polymer film in the TD direction is extremely weak. For example, a method of obtaining a biaxially oriented film by increasing the blow-up ratio by an inflation method (JP-A-56-46728, JP-A-61-102234).
), A method in which a ring die is rotated by an inflation method to apply a shearing stress in a direction perpendicular to the direction in which the film is drawn (hereinafter referred to as the MD direction) (Japanese Patent Application Laid-Open No.
JP-A-63-173620), a method of internally providing a plate-like porous body having a large number of heatable slits inside a T-die (JP-A-63-173620).
58-59818), a method of laminating an anisotropic film formed by a T-die method or an inflation method (Japanese Patent Laid-Open No. 52-10 / 1982).
9578, JP-A-58-31718, JP-A-61-89816, and JP-A-62-95213). However, an industrially useful method for producing a film that balances mechanical properties that does not easily separate and fibrillate due to external force in the TD direction has not been established. A method for industrially producing a film having good appearance, thickness accuracy, and mechanical properties balanced for practical use with good reproducibility has not yet been completed.

According to experiments by the present inventors, when a single-layer film of a liquid crystalline polymer is formed by the T-die method or the inflation method, due to the feature that the molecular structure is rigid and entanglement between molecular chains is small, The solidified material that separates from the surface layer of the liquid crystalline polymer melt fluid accumulates at the tip of the die where high shear stress is applied. The highly molecularly oriented skin layer on the film surface is fibrillated and peeled by stretching when pulled down. For this reason, there has been a problem that the surface of the formed film is rough and cannot be smoothed. Also, for example, when trying to form a thin film of 50 μm or less, stretching at a high magnification is required, the problem of peeling of the skin layer on the film surface, the problem of splitting the film due to high molecular orientation, It has become clear that it is difficult to form a thin film having a thickness of 50 μm or less.

As one method for solving such problems, a three-layer co-extrusion die is used to form a liquid crystal polymer for the intermediate layer and a non-adhesive thermoplastic polymer (polycarbonate, polyolefin) for the outer layer. A method described in JP-A-63-31729 has been proposed in which after forming a film with a three-layer structure, the outer layer is peeled off and the liquid crystal polymer film of the intermediate layer is taken out. The three-layer co-extrusion die described in JP-A-63-31729, which is generally included in a multi-layer extrusion die called a multi-manifold die, forms a film with a high thickness accuracy of each layer when designed exclusively for the raw material used. be able to. Therefore, the above JP-A-63-31729
When the liquid crystalline polymer film is molded with the three-layer co-extrusion die described in No. 2, the liquid crystal polymer film surface is protected by the thermoplastic polymer of the outer layer, so the thickness accuracy is high,
A liquid crystal polymer film having good appearance and surface flatness can be obtained.

(C) Problems to be Solved by the Invention However, according to experiments by the present inventors, the method using the multi-manifold die has high thickness accuracy,
Although a liquid crystal polymer film having a good surface flatness can be obtained, the strength in the TD direction, which is a disadvantage of the liquid crystal polymer film, is not enough to withstand practical use. Because, in the manifold die described in JP-A-63-31729, the position where the resin merges is in the die, and after the flow is widened over the entire die width in the manifold, it is merged and discharged through the slit. Because the liquid crystalline polymer in the die is highly molecularly oriented by the action of high shear stress during flow, as in the conventional single-layer extrusion die,
Since the film merges with the thermoplastic polymer of the outer layer, the disadvantage that the anisotropy of the film becomes strong and the strength in the TD direction becomes weak has not been solved.

Further, in the method described in JP-A-63-31729, a three-layer film is formed, and the liquid crystal polymer film of the intermediate layer from which the outer layer is peeled is taken out as a product. It requires a product and the production efficiency is very poor. Furthermore, in a multilayer extrusion die called a multi-manifold die disclosed as a specific three-layer coextrusion die in the above-mentioned JP-A-63-31729, it is difficult to form a multilayer structure of four or more layers because the die structure becomes too complicated. However, it is not possible to increase the production efficiency by simultaneously manufacturing two or more liquid crystal polymer films by molding a multilayer film including two or more liquid crystal polymer layers.

An object of the present invention is to establish a production method economically and industrially with good reproducibility and good reproducibility of a liquid crystal polymer film which has high thickness accuracy, good appearance, good surface flatness, and good mechanical properties. Is to do.

(D) Means for Solving the Problems As a result of intensive studies, the present inventors have found that the above object is achieved by using a feed block type co-extrusion method, and have reached the present invention.

Here, in the feed block coextrusion method, a feed block is provided before a plurality of resins are fed into the die body,
This is an extrusion method in which a merged flow is formed in advance in this portion, and then the resultant is sent to an ordinary single manifold die to widen and extrude the flow. This is an extrusion method different from the aforementioned manifold die method. As far as the present inventor knows, production of a liquid crystal polymer film using such a feed block type coextrusion method has not been known at all.

Thus, the present invention provides a thermotropic liquid crystalline polymer and a thermoplastic polymer in a feed block type co-extrusion apparatus, in which both upper and lower surfaces are thermoplastic polymer layers, and a plurality of liquid crystal polymer layers are formed between the thermoplastic polymer layers. Forming a multi-layer film by co-extruding and feeding so as to be laminated through, and then simultaneously forming a plurality of thermotropic liquid crystalline polymer films by peeling the thermoplastic polymer layer from the multi-layer film. Another object of the present invention is to provide a method for producing a liquid crystal polymer film characterized by the following.

The liquid crystalline polymer used in the present invention means a thermoplastic polymer exhibiting liquid crystallinity in a molten phase, and includes, for example, a wholly aromatic or non-wholly aromatic polyester system, an aromatic-aliphatic polyester system, and an aromatic polyazomethine system. Various synthetic polymers such as aromatic polyester carbonates, wholly aromatic or non-wholly aromatic polyester amides,
It is not limited to this. Among them, a wholly aromatic polyester-based or wholly aromatic polyesteramide-based liquid crystalline polymer can be synthesized from an aromatic diol, an aromatic diamine, an aromatic dicarboxylic acid, an aromatic hydroxy acid, or the like. Examples of the aromatic-aliphatic polyester-based liquid crystalline polymer include a copolymer of polyethylene terephthalate and hydroxybenzoic acid. Examples of the aromatic polyazomethine-based liquid crystalline polymer include poly (nitrilo-2-methyl-1,4-phenylenenitriloethylidine-1,4-phenyleneethylidine) and poly (nitrilo-2-chloro-1,4 -Phenylene nitrilomethylidine-1,4-phenylene methylidyne) and the like.
Examples of the aromatic polyester carbonate-based liquid crystalline polymer include a polymer composed of a p-oxybenzoyl group, a p-dioxyphenyl group, a dioxycarbonyl group, and a terephthalic acid group. An example of the aromatic polyester amide is, for example, a copolymer of p-aminobenzoic acid and polyethylene phthalate.

As the thermoplastic polymer forming the two outer layers of the multilayer constituent film used in the present invention, those which do not substantially exhibit adhesiveness to the liquid crystal polymer layer during molding can be used. For example, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, Polybutylene terephthalate, aromatic polyester, polyacetal, polyetherimide, polyetheretherketone, polyethersulfone, polysulfone, polyphenylenesulfide,
And polyphenylene ether.

The polymer film of the present invention is formed by a feed block coextrusion method using a T die, includes at least two liquid crystal polymer layers, and has a multilayer structure of five or more layers in which two outer layers are thermoplastic polymers. It is obtained from a film. Conventional multi-manifold die co-extrusion method using a T-die is used to melt extrude a liquid crystalline polymer and a thermoplastic polymer into a T-die from an extruder, widen and merge in the T-die, and then melt the polymer through a slit. Is extruded into a film and molded. At this time, the molten polymer, particularly the liquid crystalline polymer, is molecularly oriented in the MD direction as the extrusion is widened. The liquid crystal polymer film has a large anisotropy due to molecular orientation, and is split into split fibers,
When formed as a single layer, the highly oriented film surface layer (skin layer) is peeled off, and the appearance and flatness of the film surface are deteriorated. The high molecular orientation that causes such a problem is caused by the action of high shear stress due to the flow during widening in the T-die.

In the present invention, the two outer layers are made into a thermoplastic polymer layer in the feed block portion installed before entering the T-die, and the liquid crystal polymer layer and the thermoplastic polymer layer are appropriately arranged and laminated on the remaining intermediate layer. By doing
A multilayered molten polymer fluid in which both surfaces of the liquid crystalline polymer layer are protected is produced. Here, the number of layers of the multi-layered molten polymer fluid can be freely selected according to the purpose by five or more layers, and the configuration of the layers can also be freely selected according to the purpose. The molten polymer fluid merged and laminated at the feed block section has a T
It is sent to a die and extruded from a slit into a film. In this case, unlike the method using a multi-manifold die, the liquid crystal polymer layer is protected by the outer layer thermoplastic polymer in the T die because the width is widened after the merging,
High shear stress due to flow does not work directly. Therefore, the molecular orientation of the liquid crystal polymer is reduced, the anisotropy is small, and a liquid crystal polymer film having sufficient strength in the TD direction can be obtained. The feed block is an apparatus for laminating a molten polymer used in a co-extruded multilayer film manufacturing apparatus marketed by Dow, Eagan, Kloren, etc. in the United States.

The thermoplastic polymers forming the two outer layers and some of the inner layers of the multilayer film of the present invention may themselves be all the same or may consist of a plurality of types. That is, the thermoplastic polymer used for the multilayer constituent film can be freely selected and combined according to the purpose. However, in view of the structure of the feed block, the number of laminations is usually suitable as an absolute number and usually within 9 layers.
It is suitable to set seven layers, that is, two or three liquid crystal polymer layers.

The thickness of the multilayer film in the present invention is not particularly limited, but is preferably 10 μm to 1000 μm.
The ratio of the thickness of each layer can be freely selected according to the purpose. Then, after forming the multilayer film, the liquid crystal polymer layer and the thermoplastic polymer layer are separated from each other, whereby two or more liquid crystal polymer films can be obtained from one multilayer film.

According to the present invention, by forming a liquid crystalline polymer film by a feed block type coextrusion method, the appearance and surface flatness of the film are good as well as the conventional method using a multi-manifold die. In addition, it is possible to industrially produce a liquid crystal polymer film which has a small anisotropy and a sufficient mechanical property with sufficient mechanical properties in the TD direction and is practically used. In the method for producing a film of the present invention, two or more liquid crystalline polymer films for practical use can be produced at the same time, so that the production efficiency is remarkably higher than that of the conventional method.

Hereinafter, a method for producing the liquid crystalline film of the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows one embodiment of the method for producing a film of the present invention, and shows steps after a feed block. In this example, three extruders are used to feed block a liquid crystalline polymer, a thermoplastic polymer A having no adhesiveness to the liquid crystalline polymer, and a thermoplastic polymer B having no adhesiveness to the liquid crystalline polymer from each extruder. After being extruded inward, it was extruded through a T-die to the outside as shown in FIG. 2 containing two layers of a liquid crystalline polymer composed of three kinds of polymers.
This shows a case where a film having a layer structure is formed. In the figure,
Numeral 1 indicates a feed block of a five-layer merging type, and numeral 7 indicates a single manifold T die. In the figure,
2, 6 are polymer A channels, 4 is polymer B channels, 3 and 5 are liquid crystal polymer channels, respectively, 8 is a pressure roll, 9 is a 5-layer film, 10 is a cooling roll, and 11 and 12 are liquid crystal. Polymer films, 13 and 14 are polymer A films, 15 is polymer B
It is each showing a film.

In this embodiment, the extruder of A (not shown)
From thermoplastic polymer A without adhesiveness to liquid crystalline polymer
(Polymer A) is extruded, and a thermoplastic polymer B having no adhesiveness to the liquid crystalline polymer is extruded from an extruder (not shown) of B.
(Polymer B) is extruded, and a liquid crystalline polymer (LCP) is extruded from an extruder (not shown) of C, and each polymer is caused to flow through feed pipes A, B, and C (not shown) to feed block 1. Lead. As a result, in the multilayer fluid laminated portion in the feed block 1 following the feed pipes A, B, and C, the polymer A, the polymer B, and the LCP shown in FIG. A single-manifold T connected to a feed block with a five-layered molten polymer
It is guided to a die 7 and extruded into a film. Next, after passing through a cooling roll, the two outer layers made of polymer A are peeled off from the five-layered film to form a three-layered film, and then the three-layered film is peeled off to obtain two sheets. The liquid crystal polymer films 11 and 12 are taken out.

In the method for producing a film of the present invention, the extrusion temperature of a liquid crystalline polymer or the like is a temperature equal to or higher than the softening point of the polymer. For example, in the case of a liquid crystalline polymer, it is extruded at a temperature of 200 ° C to 400 ° C, preferably 240 ° C to 340 ° C. Here,
The softening point is the lowest temperature at which a liquid crystalline polymer or the like can melt and flow. The extrusion temperature of the thermoplastic polymer forming the outer layer when co-extruded with the liquid crystal polymer is preferably higher than the extrusion temperature of the liquid crystal polymer minus 50 ° C. More preferable extrusion temperature is the extrusion temperature of the liquid crystalline polymer minus 50 ° C. or higher, and the extrusion temperature of the liquid crystalline polymer plus 50 ° C. or lower. The molding conditions such as the temperature of the cooling roll and the film take-up speed can be freely set according to the purpose.

(E) Effects of the Invention By using the feed block type coextrusion method of the present invention, a liquid crystal polymer film having good appearance and surface flatness and good mechanical properties is provided economically and industrially. Can be obtained.

(F) Examples Hereinafter, the present invention will be described in more detail based on examples.

Example 1 As an apparatus for producing a film, an apparatus shown in FIG. 1 was used.
A film having the structure shown in FIG. 2 was formed. Liquid crystal polymer (Vectra A90, manufactured by Polyplastics Co., Ltd.)
The pellet of 0) was previously dried at a temperature of 150 ° C. for 8 hours and extruded at 290 ° C. from an extruder C. Adhered to polymer A (polypropylene manufactured by Ube Industries, Ltd., trade name: UBE Polypro TF905) which is a thermoplastic polymer that does not adhere to the liquid crystal polymer as a polymer forming the two outer layers, and a liquid crystal polymer forming the center layer Polymer B, a non-thermoplastic polymer (polypropylene manufactured by Ube Industries, Ltd., trade name
UBE Polypropylene TF905), extruder A to 260
Extruder B at 260 ° C. Then, a five-layered film shown in FIG. 2 containing two layers of liquid crystalline polymer was extruded from a T-die, and two outer layers formed by polymer A were peeled off, and then a three-layered film was peeled off. Two liquid crystal polymer films were taken out and taken out at a speed of 5 m / min. Two polymer A layers, polymer B
Layer, the thickness of each layer of the two liquid crystal polymer layers, respectively
They were 15 μm, 15 μm, 10 μm, 30 μm and 30 μm. The resulting MD direction of the liquid crystal polymer film, the tensile strength in the TD direction are each ^{4200Kg / cm 2, 1400Kg / cm} 2, together with the tear resistance is excellent, a good appearance, the surface of the flatness Was something. Further, there was no difference in performance between the two liquid crystal polymer films produced at the same time, and the production efficiency was doubled as compared with the case of Comparative Example 1 described later.

Example 2 The apparatus shown in FIG. 1 was used as a film manufacturing apparatus,
A film having the structure shown in FIG. 2 was formed. Liquid crystal polymer (Vectra A90, manufactured by Polyplastics Co., Ltd.)
The pellet of 0) was previously dried at a temperature of 150 ° C. for 8 hours and extruded at 290 ° C. from an extruder C. As the polymer forming the two outer layers, a polymer A (low-density polyethylene manufactured by Ube Industries, Ltd., trade name UBE polyethylene B128) which is a thermoplastic polymer having no adhesiveness to the liquid crystal polymer, a liquid crystal polymer forming the central layer, Polymer B which is a thermoplastic polymer having no adhesive property (polypropylene manufactured by Ube Industries, Ltd.,
Product name UBE Polypro TF905) from the extruder A
Extruded at 250 ° C. and 260 ° C. from extruder B. Then, a five-layered film shown in FIG. 2 containing two layers of liquid crystalline polymer was extruded from a T-die, and two outer layers formed by polymer A were peeled off, and then a three-layered film was peeled off. Take out 2 liquid crystal polymer films and 5m /
Withdrawn at a speed of minutes. The thicknesses of the two polymer A layers, the polymer B layer, and the two liquid crystal polymer layers were 10 μm, 10 μm, 10 μm, 30 μm, and 30 μm, respectively.
The resulting MD direction of the liquid crystal polymer film, the tensile strength in the TD direction are each ^{4100Kg / cm 2, 1400Kg / cm} 2, together with the tear resistance is excellent, a good appearance, the surface of the flatness Was something. Further, there was no difference in performance between the two liquid crystal polymer films produced at the same time, and the production efficiency was doubled as compared with the case of Comparative Example 1.

Example 3 As an apparatus for producing a film, the apparatus shown in FIG. 1 was used.
A film having the structure shown in FIG. 2 was formed. Liquid crystal polymer (Vectra A90, manufactured by Polyplastics Co., Ltd.)
The pellet of 0) was previously dried at a temperature of 150 ° C. for 8 hours and extruded at 290 ° C. from an extruder C. As a polymer for forming the two outer layers, a polymer A (polycarbonate manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Iupilon S3000) which is a thermoplastic polymer having no adhesiveness to a liquid crystal polymer was previously dried at 120 ° C. for 4 hours. The polymer B (polycarbonate manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name Iupilon S3000) which is a thermoplastic polymer having no adhesive property with the liquid crystal polymer forming the central layer was dried at 120 ° C. for 4 hours in advance. 310 ° C from extruder A and 3 ° C from extruder B respectively.
Extruded at 10 ° C. Then, a five-layered film shown in FIG. 2 containing two layers of liquid crystalline polymer was extruded from a T-die,
After the two outer layers formed of the polymer A were peeled off, the three-layer film was further peeled off, and two liquid crystal polymer films were taken out and taken out at a speed of 5 m / min.
The thickness of each of the two polymer A layers, the polymer B layer, and the two liquid crystal polymer layers is 15 μm, 15 μm, and 10 μm, respectively.
m, 30 μm, and 30 μm. The tensile strength in the MD and TD directions of the obtained liquid crystalline polymer film was 3900, respectively.
Kg / cm ^2, was 1500 Kg / cm ^2, together with the tear resistance is excellent, appearance, flatness of the surface was good. Further, there was no difference in performance between the two liquid crystal polymer films produced at the same time, and the production efficiency was doubled as compared with the case of Comparative Example 1.

Example 4 As an apparatus for producing a film, four extruders (A, B, C,
A film having a seven-layer structure shown in FIG. 3 was formed by using an apparatus using D) and a feed block capable of forming a seven-layer film. Pellets of liquid crystalline polymer (Vectra A900, trade name, manufactured by Polyplastics Co., Ltd.) forming the second, fourth, and sixth layers in FIG.
At 8 ° C. for 8 hours, from extruder B and extruder D
Extruded at 290 ° C. The polymer A (low-density polyethylene manufactured by Ube Industries, Ltd., trade name UBE polyethylene B128) forming the first layer and the seventh layer in FIG. 3, and the third layer and the fifth layer in FIG. Polymer C (polypropylene manufactured by Ube Industries, Ltd., trade name UBE Polypro TF905) as a thermoplastic polymer to be formed was extruded at 250 ° C. from extruder A and 260 ° C. from extruder C, respectively. Then, a seven-layer film shown in FIG. 3 including three liquid crystal polymers was extruded from a T-die, and the first and seventh layers formed by the polymer A were peeled off. The layers were peeled off, and two liquid crystalline polymer films were taken out and each taken out at a speed of 5 m / min. Further, the three-layered film was peeled off to obtain 4
The liquid crystal polymer film of the layer was taken out and taken out at a speed of 5 m / min. In FIG. 3, the polymer A layers of the third and fifth layers are 7 μm and 7 μm, respectively, and the liquid crystal polymer layers of the second and sixth layers are 15 μm and 15 μm, respectively.
The layer and the fifth polymer C layer are 10 μm, 10 μm, respectively.
Similarly, the fourth liquid crystal polymer layer had a thickness of 18 μm. The tensile strength in the MD and TD directions of the liquid crystalline polymer film obtained from the second layer and the sixth layer in FIG.
In ^{4100Kg / cm 2, 1400Kg / cm} 2, tensile strength in the MD direction, TD direction of the liquid crystal polymer film obtained from the fourth layer in FIG. 3 are each ^{4000Kg / cm 2, 1450Kg / cm} 2 In addition to excellent tear resistance, the appearance and the flatness of the surface were good. Further, since two liquid crystal polymer films were manufactured at the same time, the production efficiency was improved three times as compared with the case of Comparative Example 1.

Comparative Example 1 Three extruders (A, B,
C) and a multi-manifold type T die for three-layer coextrusion was used, and an apparatus similar to the method described in JP-A-63-31729, capable of peeling off two outer layers of a three-layer film was used. Liquid crystalline polymer (Polyplastics Co., Ltd.)
(Trade name, manufactured by Vectra A900) was previously dried at a temperature of 150 ° C. for 8 hours and extruded at 290 ° C. from an extruder B.
As a polymer forming the outer layer, a thermoplastic polymer having no adhesiveness to a liquid crystal polymer (polypropylene manufactured by Ube Industries, Ltd., trade name UBE Polypro TF905) was extruded at 260 ° C. from an extruder A and an extruder C. Then, a three-layer film having a liquid crystal polymer as an intermediate layer was extruded from a T-die, and two outer layers were peeled off and then taken out at a speed of 5 m / min. The thicknesses of the outer layer, the liquid crystalline polymer, and the outer layer were 15 μm, 30 μm, and 15 μm, respectively. The appearance and flatness of the surface of the obtained liquid crystalline polymer film are good, but the tensile strength in the MD and TD directions is 4100 kg / c each.
m ² , 400 kg / cm ² , and poor tear resistance.

Comparative Example 2 As a film manufacturing apparatus, a T-die single-layer film extruder was used. Pellets of liquid crystalline polymer (Vectra A900, manufactured by Polyplastics Co., Ltd.)
It was dried at a temperature of 0 ° C. for 8 hours and extruded at 290 ° C. from an extruder. Then, it was picked up at a speed of 5 m / min. The thickness of the liquid crystalline polymer film was 30 μm. The surface of the obtained liquid crystalline polymer film is rough, MD direction, TD
Direction of tensile strength, were those are inferior each 4100Kg / cm ^2, tear resistance of 120 kg / cm ^2.

[Brief description of the drawings]

FIG. 1 is a structural explanatory view showing one embodiment of the method for producing a liquid crystalline polymer film of the present invention, and FIGS. 2 and 3 each show the state of a multilayer film obtained during the production method of the present invention. FIG. 1 ... feed block, 2,6 ... polymer A flow path, 3,5 ... liquid crystalline polymer flow path, 4 ... polymer B flow path, 7 ... single manifold T-die, 8 ... pressure roll, 9 ... 5 layer film, 10 ... Cooling roll, 11,12 ... Liquid crystal polymer film, 13,14 ... Polymer A film, 15 ... Polymer B film.

Claims (1)

(57) [Claims] 1. A thermotropic liquid crystalline polymer and a thermoplastic polymer are fed to a feed block type co-extrusion apparatus by using a thermoplastic polymer layer on both upper and lower surfaces and a plurality of liquid crystalline polymer layers interposed between the thermoplastic polymer layers. A multi-layer film is formed by feeding and co-extrusion so as to be laminated, and then a plurality of thermotropic liquid crystalline polymer films are simultaneously molded by peeling the thermoplastic polymer layer from the multilayer film. Of producing a liquid crystalline polymer film.