JP2921670B2 - Method for producing isotropic liquid crystal polymer film and laminate thereof, and isotropic liquid crystal polymer film and laminate thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an isotropic liquid crystal polymer film in which anomalous orientation is largely eliminated and a laminate thereof, and to an isotropic liquid crystal polymer film and a laminate thereof.

[0002]

2. Description of the Related Art Liquid crystal polymers have excellent properties such as high strength, high heat resistance, low coefficient of linear expansion, high insulation, low moisture absorption, and high gas barrier properties. It has been put to practical use. Further, development of a printed wiring board for an IC using a liquid crystal polymer is also being studied. The liquid crystal polymer has a strong orientation. The liquid crystal polymer film which is melt-extruded from the T-die of the extruder and cooled, has a large part of the liquid crystal oriented in the extrusion direction (MD direction), and has a different orientation. Show. Therefore, such a unidirectional liquid crystal polymer film blended in one direction causes a large difference between the physical properties in the MD direction and the physical properties in the vertical direction (width direction, TD direction) with respect to the MD direction. The usability was very poor. MD / TD of liquid crystal polymer film
In order to improve the physical property balance in the direction, a method has been proposed in which a liquid crystal polymer film is stretched in the TD direction by a calender roll under a temperature condition not lower than the glass transition point of the liquid crystal polymer and not higher than the melting point (Japanese Patent Laid-Open No. 4-166309). ing. However, the liquid crystal polymer is very difficult to stretch because its melt viscosity is very high at a temperature lower than the liquid crystal transition temperature (melt temperature), unlike ordinary polymers. Therefore, the above method cannot be said to be a practical method.

[0003]

SUMMARY OF THE INVENTION The present invention relates to an industrially advantageous method for producing an isotropic liquid crystal polymer film in which anisotropic properties are largely eliminated and a laminate thereof, and an isotropic liquid crystal polymer film and a laminate thereof. The task is to provide the body.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, a thermoplastic resin film comprising a liquid crystal polymer or a polymer alloy thereof, and a thermoplastic resin film on both surfaces of an anisotropic liquid crystal polymer film in which most of the liquid crystal polymer is oriented in one direction, is heated under pressure and heated. The liquid crystal polymer film having at least a surface portion softened is thermocompression-bonded to the liquid crystal polymer film, and optionally cooled, and the resin film is peelably weakly bonded to the liquid crystal polymer film. A step of forming a laminate to obtain a laminate, and subjecting the obtained laminate to an alignment direction of the liquid crystal polymer under a temperature condition in which the liquid crystal polymer film melts but the resin film softens but does not substantially melt. Or in the direction perpendicular to the liquid crystal polymer or in the same direction as the liquid crystal polymer orientation direction, and in the direction perpendicular to the liquid crystal polymer orientation direction. A method for producing an isotropic liquid crystal polymer film, comprising: a stretching step; a cooling step of cooling the obtained stretched laminate; and a peeling step of peeling the resin film from the cooled stretched laminate. Is provided. Further, according to the present invention, a thermoplastic resin porous film and the other side are formed on one surface of an anisotropic liquid crystal polymer film comprising a liquid crystal polymer or a polymer alloy thereof, and most of the liquid crystal polymer is oriented in one direction. A non-porous thermoplastic resin film is brought into contact with the surface under pressure and under heat, and the porous film and the non-porous film are thermocompression-bonded to the liquid crystal polymer film in which at least the surface is softened. Cooling, if necessary, a laminate forming step of obtaining a laminate in which the porous film is strongly bonded to the liquid crystal polymer film and the non-porous film is weakly bonded to the liquid crystal polymer film. The liquid crystal polymer film is melted while the porous film and the nonporous film are softened but substantially not melted. And a stretching step of stretching in a direction perpendicular to the liquid crystal polymer or in the same direction as the orientation direction of the liquid crystal polymer, and a stretching step of stretching in a direction perpendicular to the orientation direction of the liquid crystal polymer, and cooling the obtained laminated body stretched product A method for producing an isotropic liquid crystal polymer film laminate, comprising a cooling step and a peeling step of peeling only the nonporous film from the cooled stretched laminate. Further, according to the present invention, in the method, a filler may be used as the liquid crystal polymer film.
There is provided a method of using an extruded film of a liquid crystal polymer or a polymer alloy thereof containing up to 30% by weight.
Further, according to the present invention, there is provided an isotropic liquid crystal polymer film obtained by the above method and a laminate thereof.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As the liquid crystal polymer used in the present invention, various known polymers such as thermotropic liquid crystal polymer can be used. Examples of such a liquid crystal polymer include aromatic polyesters that are synthesized from monomers such as aromatic diols, aromatic carboxylic acids, and hydroxycarboxylic acids and exhibit liquid crystallinity when melted.
A typical example is a first compound composed of parahydroxybenzoic acid (PHB), terephthalic acid and biphenol.
(The following formula 1), a second type consisting of PHB and 2,6-hydroxynaphthoic acid (the following formula 2), and a third type consisting of PHB, terephthalic acid and ethylene glycol (the following formula) There is equation 3).

[0006]

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[0007]

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[0008]

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In the present invention, instead of using the liquid crystal polymer alone, a polymer alloy containing the liquid crystal polymer may be used. In this case, as the alloy polymer to be mixed or chemically bonded with the liquid crystal polymer, a polymer having a melting point of 220 ° C. or more, preferably 280 to 380 ° C., for example,
Polyetheretherketone, polyethersulfone,
Polyimide, polyether imide, polyamide, polyamide imide, polyarylate and the like can be used, but are not limited to these. The mixing ratio of the liquid crystal polymer and the alloy polymer is 10:90 to 9 by weight.
0:10 is preferred, and more preferably 30: 70-7.
0:30. Polymer alloys including liquid crystal polymers also possess the excellent properties of liquid crystal polymers.

As the porous film of the thermoplastic resin used in the present invention, various films having a porous structure are used, and the average pore diameter is 0.05 to 5.0 μm, preferably 0.2 to 1 μm. Yes, the porosity is 40-95%, preferably 60-85%. Specific examples of the thermoplastic resin that forms such a porous film include polyethylene, polypropylene, polyetheretherketone, polyethersulfone, polyimide, polyetherimide, polyarylate, polycarbonate, polystyrene, and polychlorinated resin. Examples of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, fluorine resins such as polyvinyl fluoride, polyvinylidene fluoride, and poly (trifluorochloroethylene) in addition to vinyl, polyester, polyamide, and polyamideimide Can be. Among these thermoplastic resins, a fluororesin is preferable because its high heat resistance can increase the thermocompression bonding temperature and a wide selection of a liquid crystal polymer to be used. Preferred porous film used in the present invention,
It is a stretched porous fluororesin film, particularly a stretched porous polytetrafluoroethylene film in terms of heat resistance and chemical resistance. The porous thermoplastic resin film can be obtained by a conventionally known method such as a foaming method, a solvent extraction method, a solid phase drawing method, a fibrillation method, and the like.

Examples of the non-porous thermoplastic resin film used in the present invention include the non-porous films of the various resins described above.

The method for producing a stretched liquid crystal polymer film of the present invention includes a laminate forming step for obtaining a liquid crystal polymer film laminate. FIG. 1 shows a cross-sectional configuration diagram of a laminate film obtained in this laminate formation step. In FIG. 1, A denotes a liquid crystal polymer film made of a liquid crystal polymer or a polymer alloy containing the liquid crystal polymer, and most of the liquid crystal polymer is oriented in one direction. Hereinafter, these films are simply referred to as liquid crystal polymer films. On the other hand, B-1 and B-2 indicate thermoplastic resin films (hereinafter, also simply referred to as resin films). Resin films B-1 and B-2
Can be the same or different.

In the laminated film shown in FIG. 1, the melting point of the liquid crystal polymer film A is as follows.
-2, preferably below its softening point. Liquid crystal polymer is different from general thermoplastic resin, its molecules are rigid molecules, and since there is no entanglement of each molecule, when stretched at a temperature lower than the liquid crystal transition temperature, the molecules can not stretch, Causes breakage. on the other hand,
If the stretching is performed at a temperature higher than the liquid crystal transition temperature, the viscosity is too low and drawdown occurs. Therefore, a liquid crystal polymer film made entirely of a liquid crystal polymer cannot be stretched smoothly as it is. However, in the form of a laminate with a thermoplastic resin film as shown in FIG. 1, even if the liquid crystal polymer film A is melted,
Since the film shape of the melt is retained by the unmelted resin films B-1 and B-2, the film can be stretched.

In the laminated film shown in FIG. 1, the resin films B-1 and B-2 may be non-porous films. Even if the nonporous film is thermocompression-bonded to the liquid crystal polymer film, the film only weakly bonds to the liquid crystal polymer film, so that the films can be easily peeled after stretching and cooling. The peel strength of the nonporous film in this case is 1 to 5
00 g / cm, preferably about 2 to 100 g / cm. When the peel strength of the nonporous film is smaller than the above range, peeling occurs between the liquid crystal polymer film and the nonporous film when the laminate film is stretched, and the liquid crystal polymer film is smoothly stretched. It is not preferable because it becomes difficult. On the other hand, if the peel strength of the nonporous film is higher than the above range, it is difficult to peel the nonporous film after stretching, which is not preferable. The peel strength between the liquid crystal polymer film and the nonporous film can be adjusted by the thermocompression bonding conditions of both films. Hereinafter, a method for producing an isotropic liquid crystal polymer film including a laminate forming step of forming a laminate of such a liquid crystal polymer film and a nonporous film will be described in detail. This method includes a laminate forming step, a stretching step, a cooling step, and a peeling step.

(Laminate Forming Step) In this step, the nonporous films B-1 and B-2 are thermocompression-bonded to both surfaces of the liquid crystal polymer film A, respectively, to form a laminate. . The thermocompression bonding temperature is
The non-porous films B-1 and B-2 are not substantially melted, but at least the surface portion of the liquid crystal polymer film A, that is, the surface of the film A in contact with the non-porous films B-1 and B-2. This is the temperature at which only part or the whole is softened.
The thickness of the liquid crystal polymer film A is not particularly limited, but is usually 20 μm to 5 mm, preferably 50 to 800 mm.
μm, and more preferably 80 to 200 μm. The thickness of the non-porous film to be thermocompression-bonded to both surfaces thereof is not particularly limited, but is usually 10 to 200 μm, preferably 20 to 100 μm.

In order to preferably obtain a film having the above-mentioned laminated structure, non-porous films B-1 and B-2 are brought into contact with both surfaces of the liquid crystal polymer film A under pressure and heat, respectively, and at least the surface portion is formed. The non-porous films B-1 and B-2 are thermocompression-bonded to the softened liquid crystal polymer film A, respectively. In this case, the liquid crystal polymer film A is composed of two non-porous films B-1 and B-2.
Since it is sandwiched from both sides, not only the surface portion but also the whole may be in a softened state. By such thermocompression bonding, a laminate in which the nonporous films B-1 and B-2 are weakly bonded to both surfaces of the liquid crystal polymer film A is formed.

When manufacturing a laminate as described above,
As the thermocompression device, a pair of thermocompression rolls or a thermopress device is used. When a thermocompression bonding roll is used, as shown in FIG. 2, a liquid crystal polymer film A and two non-porous films B-1 and B-2 are placed in a gap between a pair of thermocompression bonding rolls 1 and 1 ( (Clearance) and thermocompression-bonded in the gap between the thermocompression rolls. In this case, the nonporous films B-1 and B-1 are provided on both sides of the liquid crystal polymer film A.
-2. The liquid crystal polymer film A can be a solid sheet or a softened film extruded from a T-die of an extruder. On the other hand, when using a hot press,
A first non-porous body film is laid on the bottom plate of the heat press device, a liquid crystal polymer film is laid thereon, and a second non-porous body film is laid on the first non-porous body film. Pressing for time, thermocompression bonding, and cooling. In this case, the bottom plate and / or the top plate are heated to soften at least the surface of the liquid crystal polymer film. The laminate obtained in the laminate film forming step is sent to the next stretching step as it is or once cooled.

(Stretching Step) In this step, the non-porous film of the laminate film obtained in the above-mentioned laminate film forming step is softened (at a glass transition temperature or higher), but is not substantially melted. Under temperature conditions that soften or melt the liquid crystal polymer film,
A step of stretching in the axial direction or biaxial direction, that is, in the direction (TD) perpendicular to the orientation direction of the liquid crystal polymer or the same direction (MD) as the orientation of the liquid crystal polymer, and in the perpendicular direction (TD). It is. In this case, the stretching ratio to MD is 1 to 10 times, preferably 1 to 5 times.
The stretching ratio to D is 1.5 to 20 times, preferably 3 to 15 times.
It is twice. Further, the stretching ratio to TD is 1.0 to 5.0 times, preferably 1.5 to 3.0 times the stretching ratio to MD. The stretching speed is 1 to 200% /
Seconds, preferably 5-50% / second. As the stretching device, a conventionally known stretching device can be used.

(Cooling step) This step is a step of cooling the stretched laminate film obtained in the biaxial stretching step and cooling and solidifying the liquid crystal polymer film in a molten state, using a pair of cooling rolls. Can be implemented. In addition, it can be performed by natural cooling.

(Peeling Step) This step is a step of peeling the non-porous film thermocompression bonded to both surfaces from the laminated film obtained in the cooling step. As described above, since the nonporous film is peelably and weakly bonded to the liquid crystal polymer film, the nonporous film is easily pulled upward from the liquid crystal polymer film. Can be peeled.

As described above, an isotropic liquid crystal polymer film can be obtained. This film is MD / T
It has an improved balance of physical properties of D and is excellent in usability. The film thickness of the isotropic liquid crystal polymer is usually 10 to 300 μm, preferably 25 to 300 μm.
Although it is 125 μm, the thickness can be further reduced by adjusting the stretching ratio as needed.

In the laminated film shown in FIG. 1, both the resin films B-1 and B-2 can be porous films. When the porous body film is thermocompression bonded to both sides of the liquid crystal polymer film, if the compression force at the time of thermocompression is weak, the porous body film is
Since the film is weakly bonded to the liquid crystal polymer film, the film can be easily peeled after stretching and cooling. The peel strength of the porous film in this case is 1 to 500 g / cm, preferably 2 to 100 g / c.
It is better to set it to about m. A method for producing an isotropic liquid crystal polymer film including a step of forming a laminate film of such a liquid crystal polymer film and a porous body film includes a stretching step, a cooling step, and a cooling step. It is performed by sequentially performing the process and the peeling process.

In the laminated film shown in FIG. 1, one of the resin films B-1 and B-2 may be a porous film, and the other may be a non-porous film. When the porous body film is thermocompressed to the liquid crystal polymer film, if the pressing force at the time of thermocompression is increased, the porous body film is strongly bonded to the liquid crystal polymer film. However, the film cannot be easily peeled off. In this case, the peel strength of the porous film was 0.5 kg /
cm or more, and is usually set to 1.0 kg / cm or more, preferably 1.2 kg / cm or more. on the other hand,
When a nonporous film is thermocompression bonded to a liquid crystal polymer film, the nonporous film is weakly bonded to the liquid crystal polymer film even if the pressure is strong during the thermocompression. After cooling, the film can be easily peeled off. In this case, the peel strength of the nonporous film is preferably set to 1 to 500 g / cm, more preferably about 2 to 100 g / cm. The method for producing an isotropic liquid crystal polymer film laminate including the step of forming such a laminate film includes, after forming the laminate film, sequentially performing a stretching step, a cooling step, and a peeling step in the same manner as described above. It is implemented by. In this case, in the peeling step, only the nonporous film is peeled. By this method, an isotropic liquid crystal polymer film laminate having a porous film firmly bonded to one surface can be obtained.

In the present invention, as the raw material liquid crystal polymer film, it is preferable to use an extruded film of a liquid crystal polymer containing 5 to 30% by weight of a filler or a polymer alloy thereof. Such a filler-containing liquid crystal polymer film has excellent surface smoothness, and the ratio B of the standard deviation B of the thickness distribution to the average value A of the thickness distribution in the direction perpendicular to the orientation direction of the liquid crystal polymer is B / A is 0.1
It is as follows.

Generally, a liquid crystal polymer film obtained by extrusion molding has an appearance like a film formed by gathering fibers, depending on the kind of the liquid crystal polymer, and many vertical stripes are observed on the MD. In addition, the surface unevenness in the transverse direction (direction perpendicular to the alignment direction (TD)) is severe. In addition, such a surface state observed in the extruded film of the liquid crystal polymer is caused by the fact that the liquid crystal polymer has another thermoplastic property. This also occurs in the case of an extruded film of a liquid crystal polymer alloy in which a polymer is alloyed.The liquid crystal polymer film having such a surface state is very difficult to use, and its use is severely restricted. On the other hand, a stretched film obtained by using a liquid crystal polymer film containing the above-described filler as a raw material film and stretching the same is used. It is no uneven thickness, but very good surface properties, the orientation direction of the liquid crystal polymer (MD)
The ratio B / A of the standard deviation B of the thickness distribution to the average value A of the thickness distribution in the direction perpendicular to the direction (TD) is 0.1 or less, particularly in the range of 0.01 to 0.05. The isotropic liquid crystal polymer film having such a surface state has been developed for the first time by the present inventors.

In order to obtain a raw material liquid crystal polymer film containing a filler, the filler is added to the liquid crystal polymer and melt-mixed. The resulting mixture is passed through a T-die or an inflation die at the end of the film using an extruder. Extrusion molding. The melt mixing temperature is a temperature at which the liquid crystal polymer shows a molten state. Of course, when the filler is a resin powder, the temperature is lower than the temperature at which the resin powder melts.
As the mixing device, a conventional mixing device such as a twin-screw extruder, a single-screw extruder, a kneader, and a mixer is used. The thickness of the extruded film is from 20 μm to 5 mm, preferably 50 μm.
８００800 μm. The extruded film thus obtained is a film having a good surface condition, and is perpendicular (TD) to the orientation direction (MD) of the liquid crystal polymer.
The ratio B / A of the standard deviation B of the thickness distribution to the average value A of the thickness distribution is 0.1 or less, particularly in the range of 0.01 to 0.05. The film has a surface roughness Rz of usually 10 μm or less, particularly 5 μm or less.

The filler includes inorganic and organic fillers. Examples of the inorganic filler include metal oxides such as silica, alumina and titanium oxide; metal carbonates such as calcium carbonate and barium carbonate; calcium sulfate;
Metal sulfates such as barium sulfate; silicates such as talc, clay, mica, and glass, as well as potassium titanate, calcium titanate, and glass fibers. Examples of the organic filler include a heat-resistant resin powder that does not melt at the processing temperature of the liquid crystal polymer, carbon, graphite, carbon fiber, and the like. Examples of the heat-resistant resin powder include polyimide, polyetherimide, polyamideimide, polyetheretherketone (PEEK), and fluororesin (PTFE, FEP, PFA, ETFE, CTF).
E, PVDF, E-CTFE, etc.), and a heat-resistant liquid crystal polymer. The filler has an average particle size of 0.01 to 50 μm, preferably 0.1 to 10 μm. The content of the filler in the liquid crystal polymer film containing the filler is 5 to 30% by weight, preferably 1 to 30% by weight.
0 to 20% by weight. If the content of the filler is more than the above range, the properties of the liquid crystal polymer film are undesirably deteriorated. If the content of the filler is too small, undesirably, vertical streaks remain in the MD of the extruded film.

The liquid crystal polymer film of the present invention is a film in which the molecules of the liquid crystal polymer are randomly oriented in the plane direction, and in which the anisotropy of the planar physical properties found in the ordinary liquid crystal polymer film is eliminated. It has excellent physical properties in plane. The planar physical properties in this case include a coefficient of linear expansion, a coefficient of thermal expansion, a coefficient of thermal shrinkage, a tensile elongation, a tensile strength, a tensile elastic modulus, and the like. The liquid crystal polymer film of the present invention has a tensile elasticity excellent in isotropic direction, and the ratio A / B of the tensile elasticity A in one plane direction to the tensile elasticity B in the other smooth direction of the film is as follows: 1/3 ~
3, preferably in the range of 2/3 to 3/2.

[0029]

Next, the present invention will be described in more detail with reference to examples.

Example 1 A thermotropic liquid crystal polymer (Sumika Super E7000, manufactured by Sumitomo Chemical Co., Ltd.) was supplied to a single screw extruder (screw diameter:
50 mm), and the T die (lip length: 500 mm, lip clearance: 1 mm) at the tip of the extruder
(Die temperature: 320 ° C.) and extruded into a film form.
m non-porous polyethersulfone (PES) film B
-1 and B-2 are laminated, and the clearance between rolls is 25.
A pair of thermocompression bonding rolls set at 0 μm (roll temperature: 3
30 ° C., roll peripheral speed: 2 m / min, diameter: 20 mm, width:
After thermocompression bonding using a pair of cooling rolls (diameter: 50 mm, temperature: 150 ° C.). Next, the laminate film thus obtained was biaxially stretched by a biaxial stretching machine, cooled, and then cooled to 260
After heat treatment at 10 ° C. for 10 minutes, the PES film was peeled off from both sides of the liquid crystal polymer film to obtain an isotropic liquid crystal polymer film having a thickness of 70 μm. The biaxial stretching,
Stretching temperature: 315 ° C., stretching speed: 10% / sec, total stretching ratio: 3 times, MD direction: 1.2 times, TD direction: 2.5 times.

Example 2 In Example 1, the non-porous PES films B-1 and B-
An experiment was carried out in the same manner except that one of the two samples used a porous PES film formed by a water casting method, and a porous PES film was formed on one surface and a non-porous PES film was formed on the other surface. A pressure-bonded isotropic liquid crystal polymer film was obtained. In this laminate, the peel strength of the porous PES film was as high as 1.3 kg / cm or more, and the peeling was difficult, but the peel strength of the non-porous PES film was 0.1 kg / cm or less. It was easily peelable. Only the non-porous PES film was peeled off from the laminate to obtain an isotropic liquid crystal polymer film laminate in which the porous PES film was thermocompression-bonded on one side.

Example 3 90 parts by weight of a thermotropic liquid crystal polymer (Sumika Super E6000 manufactured by Sumitomo Chemical Co., Ltd.) and natural silica (FS-
15, 10 parts by weight of an average particle size of 3 μm, manufactured by Denki Kagaku Co., Ltd.) were melt-mixed at 350 ° C. using a twin-screw extruder, extruded from a strand die at the tip, and formed into pellets with a pelletizer. Next, the pellet is melted in a single screw extruder (screw diameter: 50 mm), extruded into a film from a T-die (die temperature: 350 ° C.) at the tip of the extruder, and a liquid crystal polymer film (3-A) is formed. I got Next, the liquid crystal polymer film (3-
A stretched porous PTFE film (average pore diameter: 0.5 μm, thickness: 50 μm) was laminated on both surfaces of A) at 250 ° C. using a roll laminator to obtain a laminated film [ 3- AL]. The peel strength of the expanded porous PTFE film in the laminate film was 5 g / cm. Next, this laminated film [ 3- AL]
At a temperature of 350 ° C., a stretching magnification of 6 times, and a stretching speed of 100% /
The film was uniaxially stretched to TD under the condition of seconds. Next, the stretched porous PTFE film in the laminate film [ 3- ALE] thus obtained was peeled off to obtain an isotropic liquid crystal polymer film [ 3- AE] having a thickness of 47 μm.

Example 4 95 parts by weight of a thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) and titanium oxide (CR-
And 5 parts by weight (Ishihara Sangyo Co., Ltd.) at 350 ° C. using a twin-screw extruder, and extruded from a T-die at the tip to form pellets. Next, the pellet is melted in a single screw extruder (screw diameter: 50 mm), extruded into a film from a T-die (die temperature: 350 ° C.) at the tip of the extruder, and a liquid crystal polymer film [ 4- B] is obtained. I got Next, on both sides of the liquid crystal polymer film [ 4- B] obtained above, an expanded porous PTFE film (average diameter 0.5 μm, thickness 50 μm)
m) was laminated at 250 ° C. using a roll laminator to obtain a laminated film [ 4- BL]. The peel strength of the expanded porous PTFE film in the laminate film was 5 g / cm. Next, this laminated film [ 4- BL] was heated at a temperature of 350 ° C and a draw ratio of 6
The film was uniaxially stretched in the TD under the conditions of a stretching speed of 100% / sec. Next, the thus obtained laminate film [ 4
-BLE], the stretched porous film is peeled off, and the isotropic liquid crystal polymer film [ 4- BE] having a thickness of 48 μm is formed.
I got

Example 5 A thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) was extruded into a single screw extruder (screw diameter: 5).
0 mm) and extruded into a film from a T-die (die temperature: 350 ° C.) at the tip of the extruder to obtain a liquid crystal polymer film [ 5- C]. Next, on both sides of the liquid crystal polymer film [ 5- C] obtained above, stretched porous PT
An FE film (average diameter 0.5 μm, thickness 50 μm) is laminated at 250 ° C. using a roll laminator,
A laminated film [ 5- CL] was obtained. The peel strength of the expanded porous PTFE film in this laminate film was 0.1 kg / cm. Next, the laminated film [ 5- CL] was heated at a temperature of 350 ° C. and a draw ratio of 6
The film was uniaxially stretched in the TD under the conditions of a stretching speed of 100% / sec. Next, the thus obtained laminate film [ 5
-CLE] by peeling off the stretched porous film and a 47 μm-thick isotropic liquid crystal polymer film [ 5- CE]
I got

Next, for each of the liquid crystal polymer films and laminates obtained in Examples 3 to 5 , the TD thickness distribution, the TD thickness average value, the standard deviation, and the tensile strength of the films were determined as follows. The results are shown in Table 1.

(Measurement of TD Thickness Distribution of Film) A needle-type measuring element (tip R: 0.4 mm) of a dial gauge (manufactured by Mitutoyo Corporation) is vertically fixed, and is contacted with a force of 100 g. Next, a sample film is sandwiched between the tracing styluses and moved in the TD direction. In this way, TD thickness distribution data of the film is obtained.

(Average TD Thickness of Film) Based on the data of the TD thickness distribution of the film obtained as described above, it was calculated as follows. That is, width 100
0.5 m in the width direction (TD) of the 0 mm film
2000 points were measured at m intervals, and the average value C was obtained.

(Standard Deviation of TD Thickness Distribution of Film) The average value of the TD thickness of the film obtained as described above and 2
The standard deviation D was determined based on the 000 point measurement value.

(Surface Roughness) Measured in accordance with JIS B0601. In this case, as a surface roughness meter, Surfcom 1500 manufactured by Tokyo Seimitsu Co., Ltd.
Use A.

(Tensile strength) Measured according to JIS K 7127.

[0041]

[Table 1]

[0042]

The isotropic liquid crystal polymer film of the present invention has a good balance of planar physical properties and can be advantageously used in a wide range of fields.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of a laminate sheet obtained in a laminate formation step.

FIG. 2 is an explanatory diagram illustrating an example of a method for manufacturing the laminate sheet illustrated in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermocompression roll 2 Guide roll A Liquid crystal polymer film B-1, B-2 thermoplastic resin film

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 55/02-55/28 C08J 5/18 CFD B32B 27/00-27/36

Claims (6)

(57) [Claims] 1. A thermoplastic resin film is contacted under pressure and with heat on both surfaces of an anisotropic liquid crystal polymer film comprising a liquid crystal polymer or a polymer alloy thereof, and most of the liquid crystal polymer is oriented in one direction. The resin film is thermocompressed to the liquid crystal polymer film in a state where at least a surface portion is softened, and cooled if necessary, and the resin film is weakly peelably bonded to the liquid crystal polymer film. A laminate forming step of obtaining a body, the obtained laminate, under a temperature condition in which the liquid crystal polymer film melts but the resin film softens but does not substantially melt, the liquid crystal polymer is perpendicular to the orientation direction of the liquid crystal polymer. Or stretching in the same direction as the orientation direction of the liquid crystal polymer, and stretching in a direction perpendicular to the liquid crystal polymer orientation direction; A method for producing an isotropic liquid crystal polymer film, comprising: a cooling step of cooling the obtained stretched laminate; and a peeling step of peeling the resin film from the cooled stretched laminate. 2. The method according to claim 1, wherein in the step of forming a laminate, a stretched porous film of a fluororesin is used as the thermoplastic resin film. 3. The method according to claim 1, wherein the thermocompression bonding of the thermoplastic resin film to the liquid crystal polymer film is performed using a pair of thermocompression rolls or a hot press. 4. A thermoplastic resin porous film on one side of an anisotropic liquid crystal polymer film comprising a liquid crystal polymer or a polymer alloy thereof, and most of the liquid crystal polymer is oriented in one direction, and a liquid crystal polymer on the other side. The non-porous thermoplastic resin film is contacted under pressure and under heat, and the porous film and the non-porous film are thermocompressed to the liquid crystal polymer film in a state where at least the surface is softened,
Cooling, if necessary, a laminate forming step of obtaining a laminate in which the porous film is strongly bonded to the liquid crystal polymer film and the non-porous film is weakly bonded to the liquid crystal polymer film; The laminate is stretched in a direction perpendicular to the orientation direction of the liquid crystal polymer under a temperature condition in which the liquid crystal polymer film melts but the porous film and the non-porous film soften but do not substantially melt. Or stretching in the same direction as the orientation direction of the liquid crystal polymer, a stretching step of stretching in a direction perpendicular to the orientation direction of the liquid crystal polymer, a cooling step of cooling the obtained laminate stretched product, A method for producing an isotropic liquid crystal polymer film laminate, comprising a peeling step of peeling only the nonporous film from the stretched laminate. 5. As the liquid crystal polymer film, a liquid crystal polymer or method of any of claims 1-4 using an extrusion molded film of the polymer alloy containing a filler 5 to 30 wt%. 6. The method of claim 1 isotropic liquid crystal polymer film or laminate thereof obtained by the method of any of 5.