JP2003291210A - Method and apparatus for manufacturing liquid crystal polymer film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for efficiently manufacturing a thermoplastic liquid crystal polymer film in which a wear resistance is improved and a thermal expansion coefficient is regulated. <P>SOLUTION: The method for manufacturing the thermoplastic liquid crystal polymer film comprises the steps of: extruding the thermoplastic polymer (called a 'thermoplastic liquid crystal polymer') capable of forming an optically anisotropic melt phase together with the polymer having a higher melting point than the liquid crystal polymer from an annular die, forming a film of a laminated structure by an inflation process, heat treating the obtained film of the laminated structure near at a melting point of the liquid crystal polymer, and then separating the film into a film made of a polymer having a higher melting point than the liquid crystal polymer and a thermoplastic liquid crystal polymer film. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method and an apparatus for producing a liquid crystal polymer film.

[0002]

2. Description of the Related Art A film made of a thermoplastic polymer capable of forming an optically anisotropic molten phase (hereinafter sometimes referred to as a thermoplastic liquid crystal polymer) has a mechanical strength, an electrical property, a heat resistance and a heat resistance. Shows excellent performance in chemical resistance, chemical resistance, and dimensional stability. Therefore, in particular in the electronic field, attention is focused on as an insulating material, a printed circuit board material, a laminated material, and the like, and in other fields, various applications in which heat resistance is required, such as heat resistant laminated material applications, are expected.

A film made of a thermoplastic liquid crystal polymer can be usually produced by an inflation method, but the thermal expansion coefficient of the obtained film is often a negative value, and the film is highly oriented in the thickness direction. Therefore, delamination is likely to occur and the film may have low abrasion resistance. Therefore, when it is used as a circuit board material or industrial material that takes advantage of the excellent heat resistance, chemical resistance, and high frequency electrical characteristics of liquid crystal polymers, it is possible to adjust the thermal expansion coefficient and improve wear resistance. preferable.

Therefore, conventionally, there has been proposed a method of producing a film by incorporating a filler having a large thermal expansion coefficient into a thermoplastic liquid crystal polymer or a filler such as glass fiber. According to this, by including the filler or the filler, the characteristics originally possessed by the thermoplastic liquid crystal polymer are deteriorated and it is difficult to form a thin film. Further, a method of heating the film in a state where at least one surface of the thermoplastic liquid crystal polymer film is in contact with a support to improve abrasion resistance and to adjust a thermal expansion coefficient (Japanese Patent Laid-Open No. 8-90570). It has been known. In the method described in the publication, a support is used to maintain the shape of the thermoplastic liquid crystal polymer film during heat treatment. The support is required to be one that does not substantially deform at the processing temperature of the film, and examples of the material thereof include metals, inorganic substances, highly heat resistant resins (polyimide, etc.) and the like. In the examples of the publication, a support made of a metal is mainly used, but a polyimide film or a polytetrafluoroethylene film is also used.

[0005]

[Patent Document 1] Japanese Patent Application Laid-Open No. 8-90570
The method described in the publication is a step of producing a thermoplastic liquid crystal polymer film, a step of closely adhering or adhering the film to a separately prepared support to form a laminated structure, and a step of heat-treating the obtained laminated structure. , And separating the film after heat treatment from the support. Therefore, the present invention is to improve such a method, to provide a method and an apparatus therefor capable of more efficiently producing a thermoplastic liquid crystal polymer film having improved abrasion resistance and controlled thermal expansion coefficient. And

[0006]

According to the present invention, the above-mentioned problems are solved by a thermoplastic polymer capable of forming a melt phase having optical anisotropy (hereinafter referred to as a thermoplastic liquid crystal polymer).
Is extruded together with a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer through a ring die to form a film having a laminated structure by an inflation method, and the obtained film having a laminated structure is heat treated near the melting point of the thermoplastic liquid crystal polymer. And a method for producing the thermoplastic liquid crystal polymer film, which comprises separating a film made of a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer and a thermoplastic liquid crystal polymer film. Further, a thermoplastic liquid crystal polymer, an annular die for forming a film having a laminated structure by melt-extruding a polymer having a melting point higher than its melting point, a pair of rolls for folding the film having a laminated structure extruded from the annular die, A slit device for cutting both ends of the laminated film, a heat treatment furnace provided on the downstream side of the slit device for heat treating the laminated film cut by the slit device, and a heat treatment furnace provided on the downstream side of the heat treatment furnace for heat treatment. And a separating means for separating the thermoplastic liquid crystal polymer film from the film having the laminated structure.

A three-layer coextrusion die is used to produce a three-layer film comprising a thermoplastic liquid crystal polymer film (intermediate layer) and another resin (outer layer), and the outer layer thermoplastic liquid crystal polymer film is taken out. A method for producing a thermoplastic liquid crystal polymer film comprising
No. 29 and Japanese Patent Laid-Open No. 178016/1990, it is different from the method of the present invention in that it uses extrusion molding with a T-die and is not an inflation method. Further, there is no description in the above publication that heat treatment is performed on the obtained three-layer film.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The raw material of the thermoplastic liquid crystal polymer used in the present invention is not particularly limited, but specific examples thereof are classified into the following (1) to (4). Known thermotropic liquid crystal polyesters and thermotropic liquid crystal polyester amides derived from the compounds and their derivatives can be mentioned. However, in order to obtain a polymer capable of forming an optically anisotropic molten phase, it goes without saying that the combination of each raw material compound has an appropriate range.

(1) Aromatic or aliphatic dihydroxy compounds (see Table 1 for representative examples)

[0010]

[Table 1]

(2) Aromatic or aliphatic dicarboxylic acid (see Table 2 for typical examples)

[0012]

[Table 2]

(3) Aromatic hydroxycarboxylic acid (see Table 3 for representative examples)

[0014]

[Table 3]

(4) Aromatic diamine, aromatic hydroxyamine or aromatic aminocarboxylic acid (see Table 4 for representative examples)

[0016]

[Table 4]

As typical examples of thermoplastic liquid crystal polymers obtained from these raw material compounds, copolymers (a) to (e) having the structural units shown in Table 5 can be mentioned.

[0018]

[Table 5]

The melting point of the thermoplastic liquid crystal polymer used in the present invention is not particularly limited, but it is about 2 from the viewpoint of workability.
It is preferably in the range of 0 to about 400 ° C., and about 2
More preferably in the range of 50 to about 350 ° C.
The thermoplastic liquid crystal polymer is a thermoplastic resin such as a polyolefin resin, a polyester resin different from the thermoplastic liquid crystal polymer, a polyvinylidene chloride resin, a polyacetal resin, a polycarbonate resin, etc. within a range not impairing the gist of the invention. May be blended with.
Further, the thermoplastic liquid crystal polymer, for example, an antioxidant,
You may contain additives, such as a coloring agent, a plasticizer, and a filler.

Further, as a polymer having a higher melting point than the above-mentioned thermoplastic liquid crystal polymer used in the present invention (hereinafter sometimes abbreviated as high melting point polymer), its melting point (Ts (° C.)) is a thermoplastic liquid crystal. Those satisfying the relationship of Tm <Ts ≦ Tm + 30 with respect to the melting point (Tm (° C.)) of the polymer film are preferably used. Examples of the high melting point polymer include fluororesins such as tetrafluoroethylene. Further, a mixture of a high melting point polymer and a polymer having a melting point lower than that of the thermoplastic liquid crystal polymer such as polyphenylene sulfide can be used as long as the melting point of the mixture is higher than the melting point of the thermoplastic liquid crystal polymer. The high-melting point polymer preferably has a viscosity at the time of melt extrusion that is similar to that of the thermoplastic liquid crystal polymer. Further, the high melting point polymer may contain additives such as a thickener, an antioxidant, a plasticizer and a filler.

In the present invention, the above-mentioned thermoplastic liquid crystal polymer and high melting point polymer are extruded from a ring die to obtain a film having a laminated structure comprising a thermoplastic liquid crystal polymer layer and a high melting point polymer layer by an inflation method. The film having a laminated structure is a film having a two-layer structure composed of one thermoplastic liquid crystal polymer layer and one high melting point polymer layer (type A), and one thermoplastic liquid crystal polymer layer is sandwiched between two high melting point polymer layers. Of various structures, such as a three-layer structure film (type B), a three-layer structure film (type C) in which one high melting point polymer layer is sandwiched between two thermoplastic liquid crystal polymer layers. However, type A or C is preferable, and type A is more preferable.

By utilizing the inflation method, the mechanical properties and heat in the machine axis direction (hereinafter, sometimes abbreviated as MD direction) and the direction orthogonal thereto (hereinafter, sometimes abbreviated as TD direction). A film having a well-balanced property is obtained.

The thickness of the thermoplastic liquid crystal polymer layer (which becomes a thermoplastic liquid crystal polymer film after the separation step described below) in the film having a laminated structure is not particularly limited, but is in the range of 15 to 150 μm. Preferably,
More preferably, it is in the range of 20 to 50 μm. Further, the thickness of the high melting point polymer layer (which becomes a high melting point polymer film after the separation step described below) in the film having a laminated structure is not particularly limited, and a film having a laminated structure is produced. Although it can be appropriately set depending on the production conditions at that time, it is usually preferable that the thickness is equal to or more than that of the thermoplastic liquid crystal polymer layer, and the upper limit is twice the thickness of the thermoplastic liquid crystal polymer layer. preferable.

In the present invention, the laminated film thus obtained is heat-treated near the melting point of the thermoplastic liquid crystal polymer. By such heat treatment, the coefficient of thermal expansion of the thermoplastic liquid crystal polymer layer (film) in the film having a laminated structure is adjusted, and the abrasion resistance is improved.

The temperature (T (° C.)) when heat-treating a film having a laminated structure is Tm <T ≦ Tm + 20, and T <Ts.
It is preferable that it is within the range from the viewpoint that an excessive heat load can be avoided and the manufacturing cost can be suppressed. The heat treatment of the film having a laminated structure can be carried out by a known method such as a method of blowing hot air, a method of irradiating infrared rays, a method of immersing in a heat medium oil, or a method of hot pressing. The time required for the heat treatment can be appropriately selected depending on the conditions such as the temperature of the heat treatment, the means for performing the heat treatment, the type of high melting point polymer used, and the thickness of the film having a laminated structure, but usually 1 second to 15 minutes. Within the range of.

In the production method of the present invention, after the film having the laminated structure is heat treated as described above, the thermoplastic liquid crystal polymer layer and the high melting point polymer layer of the film are separated,
A desired thermoplastic liquid crystal polymer film is obtained. Separation can be achieved by a known method such as a T peeling method (90 ° peeling method) or a peeling method such as a 180 ° peeling method.

A film made of a high melting point polymer can be obtained by the separation step. Such a film is washed and crushed if necessary, and then again extruded with a thermoplastic liquid crystal polymer to form a film having a multilayer structure. It can be recovered and reused as a raw material. Such recovery / reuse is preferable from the viewpoint of effective use of resources, and can reduce the raw material unit price, leading to a reduction in manufacturing cost. Although the film made of the high melting point polymer obtained by the separation step depends on the degree of deterioration due to the heat load during the heat treatment, it is desirable that 20 to 80% by weight of the raw material at the time of extrusion molding is constituted by the recovered product.

In the production method of the present invention described above, the thermoplastic liquid crystal polymer and the high melting point polymer which serves as a support for the thermoplastic liquid crystal polymer during heat treatment are simultaneously extruded to form a film having a laminated structure. In the method described in Japanese Patent No. 90570, a step of producing a thermoplastic film and a step of closely adhering or adhering the thermoplastic film and a support are simultaneously performed. Therefore, the production efficiency is improved.

Next, the apparatus for producing the thermoplastic liquid crystal polymer film of the present invention will be described. FIG. 1 is a schematic view showing an embodiment of an apparatus for producing a thermoplastic liquid crystal polymer film of the present invention.

The manufacturing apparatus shown in FIG. 1 is provided with an annular die for extruding a thermoplastic liquid crystal polymer and a polymer having a melting point higher than that of the polymer to form an annular double-layered film, and a downstream die of the die. A heat-treating furnace for heat-treating the film having a two-layer structure extruded from this is provided. In such a manufacturing apparatus, a pair of rolls that fold an annular two-layer structure film extruded from an annular die, a slit device that cuts both ends of the two-layer film, and a downstream side of the slit device. And a separating means for separating the heat-treated double-layered film, which is provided on the downstream side of the heat-treatment furnace.

In the above manufacturing apparatus, the thermoplastic liquid crystal polymer and the polymer having a melting point higher than that of the thermoplastic liquid crystal polymer are both used in the annular die 2.
Is melt-extruded to obtain a double-layered film 4 having a layer (film) made of a thermoplastic liquid crystal polymer and a layer (film) made of a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer.

Then, the double-layered film 4 is folded by a pair of rolls 5 and 5 ', both ends thereof are cut by a slit device 7 and supplied to a heat treatment furnace 8 on the downstream side for heat treatment. Then, it is sent to a separating means (roll) 9 provided on the downstream side of the heat treatment furnace 8 and continuously separated into a thermoplastic liquid crystal polymer film F1 and a high melting point polymer film F2.

Since the manufacturing apparatus of the present invention can be constructed by combining a normal inflation manufacturing apparatus with a heat treatment furnace, the entire apparatus can be made compact and compact.

[0034]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, the coefficient of thermal expansion and abrasion resistance of the thermoplastic liquid crystal polymer film were evaluated by the following methods. (1) Thermal expansion coefficient Using a thermomechanical analyzer, the thermal expansion coefficient is 20 in a 5 mm width.
In a state where a tensile load of 1 g was applied to a film having a length of mm, the temperature was raised from 30 ° C. to 150 ° C. at a temperature raising rate of 10 ° C./min, and calculation was performed based on the amount of change in the length of the film. (2) Abrasion resistance The surface was rubbed with a commercially available plastic eraser and visually evaluated.

Example 1 Using the inflation manufacturing apparatus shown in FIG. 1, p-
A pellet of an aromatic polyester (VECTRA900F, manufactured by Hoechst Celanese Co., Ltd.) which is a copolymer of hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid and forms an optically anisotropic molten phase having a melting point of 280 ° C. Melt-extruded ethylene-tetrafluoroethylene (Mitsui Fluorochemical Co., Tefzel 70G-25, melting point 300 ° C), which is a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer, at 290 ° C using a 60 mmφ coextruder, and formed into a ring. Die (diameter 2
5 mm and a gap of 0.6 mm) was discharged to form a two-layered annular film composed of a thermoplastic liquid crystal polymer layer (film) and an ethylene-tetrafluoroethylene layer (film).

As conditions for inflation molding, air is supplied to the inner space while the outer surface of the annularly extruded film is cooled, and the film is expanded by the inner pressure (expansion rate:
(3 times) A cylindrical stretched film having a two-layer structure was formed. In the obtained film, the thickness of the thermoplastic liquid crystal polymer layer was 50 μm, and the thickness of the ethylene-tetrafluoroethylene layer was 50 μm. Following this, after folding the cylindrical stretched film, both ends thereof were cut by a slit device, and then passed through a hot air type heat treatment furnace having a furnace length of 1 m and heated and held at 280 ° C. Then, the heat-treated double-layered film was separated from each other by a separation roll, and the thermoplastic liquid crystal polymer film and the ethylene-tetrafluoroethylene film were respectively wound on a winding roll (winding speed:
3 m / min).

Table 6 shows the physical properties of the thermoplastic liquid crystal polymer film thus obtained.

Comparative Example 1 A thermoplastic liquid crystal polymer film was obtained in the same manner as in Example 1 except that the hot air heat treatment furnace was not used. The physical properties of the film are shown in Table 6.

[0039]

[Table 6]

Example 2 Commercially available ethylene-tetrafluoroethylene [Tefzel 70G-
25, manufactured by Mitsui Fluorochemicals Co., Ltd.] 100 parts by weight,
400 parts by weight of the pulverized product of the ethylene-tetrafluoroethylene film obtained in Example 1 was mixed. The same operation as in Example 1 was carried out except that this was used as a high melting point polymer extruded together with a thermoplastic liquid crystal polymer, and a thermoplastic liquid crystal polymer film and an ethylene-tetrafluoroethylene film were obtained through a heat treatment and a separation step. It was The physical properties of the obtained thermoplastic liquid crystal polymer film were the same as those obtained in Example 1.

[0041]

As described above, according to the present invention, the thermal expansion coefficient can be improved and abrasion resistance can be improved with simple equipment.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an inflation film manufacturing apparatus according to the present invention.

[Explanation of symbols]

2 ... Inflation die, 5 ... Roll, 7 ... Slit device, 8 ... Heat treatment furnace, 9 ... Separation roll.

Claims (6)

[Claims] 1. A thermoplastic polymer capable of forming an optically anisotropic molten phase (hereinafter referred to as a thermoplastic liquid crystal polymer) is extruded from a ring die together with a polymer having a higher melting point than the thermoplastic liquid crystal polymer. , A film having a laminated structure is formed by an inflation method, the obtained film having a laminated structure is heat-treated near the melting point of the thermoplastic liquid crystal polymer, and then a film made of a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer and a thermoplastic film A method for producing the thermoplastic liquid crystal polymer film, which comprises separating the liquid crystal polymer film. 2. The melting point (Ts (° C.)) of the polymer having a higher melting point than the thermoplastic liquid crystal polymer is Tm <Ts ≦ T with respect to the melting point (Tm (° C.)) of the thermoplastic liquid crystal polymer.
The method for producing a liquid crystal polymer film according to claim 1, which satisfies the relationship of m + 30. 3. The method for producing a liquid crystal polymer film according to claim 1, wherein a temperature T (° C.) at the time of heat-treating the film having a laminated structure is within a range of Tm ≦ T ≦ Tm + 20 and T <Ts. 4. The method for producing a film according to claim 1, wherein the film having a laminated structure is a film having a two-layer structure. 5. The film according to claim 1, wherein the separated film composed of the high melting point polymer is recovered and reused as at least a part of the high melting point polymer when the film is extruded together with the thermoplastic liquid crystal polymer. Manufacturing method. 6. An annular die for forming a laminated film by melt-extruding a thermoplastic liquid crystal polymer and a polymer having a melting point higher than that of the thermoplastic liquid crystal polymer, and a pair of rolls for folding the laminated film extruded from the annular die. A slit device for cutting both ends of the laminated film, a heat treatment furnace provided on the downstream side of the slit device for heat treating the laminated film cut by the slit device, and provided on the downstream side of the heat treatment furnace. And a separation means for separating the thermoplastic liquid crystal polymer film from the heat-treated laminated film.