JPH1034742A - Liquid crystal polymer film and its laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of anistropy of physical properties and to obtain a liquid crystal polymer film having a small coefficient of linear thermal expansion and a small thermal shrinkage percentage by specifying the coefficient of linear thermal expansion and the thermal shrinkage percentage in the plane direction of an isotropic film in which liquid crystal polymer molecules are oriented randomly in the plane direction. SOLUTION: A liquid crystal polymer film which is made from a thermotropic liquid crystal polymer or its polymer alloy and in which liquid crystal polymer molecules containing 5-30vol.% of a filler are oriented randomly. The coefficient of linear thermal expansion in an optional plane direction of the film is made to be 20ppm/ deg.C or less, the thermal shrinkage percentage is made to be 0.1% or less, and the tensile elastic modulus is made to be 600kg/mm<2> or more, and the ratio A/B of the coefficient of linear thermal expansion A in one plane direction to that B in another direction is made to be 0.3-3. The ratio D/C of the standard deviation D of thickness distribution to the average C of the thickness distribution of the film is made to be 0.2 or less, and the surface roughness Rz of the film is made to be 10μm or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal polymer film excellent in isotropic properties of flat physical properties, in which anisotropic properties of flat physical properties are largely eliminated, and a laminate thereof.

[0002]

2. Description of the Related Art Thermotropic liquid crystal polymers (hereinafter referred to as "thermotropic liquid crystal polymers").
LCP) is a polymer that exhibits liquid crystallinity in the molten state and has excellent properties such as high strength, high heat resistance, low coefficient of linear thermal expansion, high insulation, low moisture absorption, and high gas barrier properties. It has already been put to practical use as injection molded parts and fibers. The use of LCP films is also expected in the field of electronic materials and packaging. However, when the LCP film is melt-extruded from a die to be processed, its molecules are remarkably oriented in the direction in which it is extruded, and the resulting film may have cracks in the machine direction (MD) or may have no cracks. Long direction of film (orientation direction of LCP)
There is a problem in that the physical properties such as tensile strength, tensile elongation, tensile elastic modulus, and linear expansion coefficient in the (MD) and width directions (perpendicular to the LCP orientation direction) (TD) are large.

[0003] For this reason, a technique for alleviating the misdirection in the MD / TD of the LCP film has been proposed. For example, as a technique for alleviating the misdirection in the MD / TD, a technique based on an inflation method (Japanese Patent Laid-Open No. 01-301) has been proposed. 34
134, JP-A-03-152131, and JP-A-05-43664), by an inflation method using a rotating die (JP-A-63-199622, JP-A-01-130930, 02-
No. 89616, JP-T-Hei 04-506779)
And so on. However, although the LCP film obtained by these methods can basically solve the problem of physical property balance in MD / TD, the surface roughness inherent to the liquid crystal polymer (poor surface smoothness, uneven thickness, streaks, etc.) ) The problem remains. An LCP film having satisfactory physical properties has not yet been obtained. JP-A-7-323506 proposes a method of manufacturing an LCP film in which a synthetic resin film is laminated on both sides of an LCP film and then stretched at a temperature at which a liquid crystal polymer melts. According to this, a uniform film in which liquid crystal polymer molecules are randomly oriented in a plane direction can be obtained. However, according to the experiments of the present inventors, the LCP obtained by this method was
The film has a linear expansion coefficient of 20 ppm in the planar direction.
/ ° C, thermal shrinkage rate is higher than 0.05%, and tensile modulus is lower than 600 kg / mm ² , low linear expansion coefficient, low heat shrinkage rate, high tensile modulus inherent to liquid crystal polymers. It cannot be said that the physical properties such as are fully exploited.

[0004]

SUMMARY OF THE INVENTION The present invention provides a liquid crystal polymer film made of a thermotropic liquid crystal polymer or a polymer alloy thereof, in which different directions of physical properties in a plane direction are eliminated, and a linear expansion coefficient and a heat shrinkage are reduced. Another object of the present invention is to provide a liquid crystal polymer film having a high tensile modulus and a laminate thereof.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, an isotropic liquid crystal polymer film in which liquid crystal polymer molecules composed of a thermotropic liquid crystal polymer or a polymer alloy thereof are randomly oriented in a plane direction, and a linear expansion of the film in an arbitrary plane direction. The coefficient is 20 ppm / ° C or less, the heat shrinkage is 0.05% or less, and the tensile modulus is 600 kg / mm.
A liquid crystal polymer film having a ratio A / B of at least ² and a linear expansion coefficient A in one plane direction and a linear expansion coefficient B in another plane direction of 0.3 to 3; Is done. Further, according to the present invention, it is composed of a thermotropic liquid crystal polymer or its polymer alloy,
An isotropic liquid crystal polymer film in which liquid crystal polymer molecules containing 30% by volume are randomly oriented in a plane direction, wherein the coefficient of linear expansion of the film in any plane direction is 20 ppm / ° C. or less and the heat shrinkage is 0.1%. 1% or less and the tensile modulus of elasticity is 600 kg / mm ² or more, and the ratio A / B of the linear expansion coefficient A in one plane direction to the linear expansion coefficient B in another plane direction is in the range of 0.3 to 3. And the ratio D / C of the standard deviation D of the thickness distribution to the average value C of the thickness distribution of the film is 0.2 or less, and the film surface roughness R
A liquid crystal polymer film is provided, wherein _Z is 10 μm or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As the thermotropic liquid crystal polymer (LCP) in the present invention, various conventionally known polymers can be used. As such an LCP,
For example, there is an aromatic polyester that is synthesized from monomers such as aromatic diols, aromatic carboxylic acids, and hydroxycarboxylic acids, and exhibits liquid crystallinity when melted. Typical examples thereof include parahydroxybenzoic acid (PHB). A first type composed of terephthalic acid and biphenol (the following formula 1), a second type composed of PHB and 2,6-hydroxynaphthoic acid (the following formula 2), and composed of PHB, terephthalic acid and ethylene glycol There is a third type (formula 3 below).

[0007]

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[0008]

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[0009]

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In the present invention, instead of using LCP alone, a polymer alloy containing LCP may be used. In this case, the alloy polymer to be mixed or chemically bonded to the LCP has a melting point of 220 ° C. or higher, preferably 280 ° C.
Polymers at 〜380 ° C., for example, polyetheretherketone, polyethersulfone, polyimide, polyetherimide, polyamide, polyamideimide, polyarylate, and the like can be used, but are not limited thereto. The mixing ratio of LCP to the alloy polymer is preferably from 10:90 to 90:10, more preferably from 30:70 to 70:30, by weight. Polymer alloys containing LCP also retain the excellent properties of LCP.

The synthetic resin film of the present invention contains a porous film and a nonporous film. As the porous film, various films having a porous structure are used, and the average pore diameter is 0.05 to 5.0 μm,
Preferably, it is 0.2-1 μm, and the porosity is 40-95.
%, Preferably 60 to 85%. As a synthetic resin forming such a porous body film, specifically,
Polyethylene, polypropylene, polyetheretherketone, polyethersulfone, polyimide, polyetherimide, polyarylate, polycarbonate, polystyrene, polyvinyl chloride, polyester, polyamide,
In addition to polyamideimide, polytetrafluoroethylene,
Thermoplastic resins such as a tetrafluoroethylene / hexafluoropropylene copolymer, polyvinyl fluoride, polyvinylidene fluoride, and a fluororesin such as poly (trifluorochloroethylene) can be exemplified. Among these 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. A preferred porous film used in the present invention is a stretched porous fluororesin film, particularly a stretched porous polytetrafluoroethylene film in terms of heat resistance and chemical resistance. The resin porous film can be obtained by a conventionally known method such as a foaming method, a solvent extraction method, a solid-phase stretching method, and a fibrillation method. Examples of the non-porous film include a non-porous film of the resin.

To obtain the isotropic LCP film of the present invention, first, an extruded film of LCP or a polymer alloy thereof (hereinafter, also simply referred to as LCP) is prepared. The extruded film of LCP in this case is LC
The melt of P can be obtained by extruding into a film using an extruder through a T-die or an inflation die at the tip thereof. The melting temperature is a temperature at which the liquid crystal polymer shows a molten state. As the extruder, a conventional device such as a twin-screw extruder or a single-screw extruder is used. The thickness of the extruded film is from 20 μm
5 mm, preferably 50-800 μm. When an LCP extruded film is obtained as described above, it is important that the draft ratio at the time of the extrusion molding is set to 10 or more, preferably 10 to 20. By using an LCP film extruded at such a draft ratio as a raw material film and stretching it, the liquid crystal polymer molecules are randomly oriented in the plane direction, and the anisotropy of the physical properties in the plane direction is eliminated. Isotropic LCP with low coefficient of expansion and heat shrinkage and high tensile modulus
It becomes possible to obtain a film. The meaning of the draft ratio is as follows. Next, the extruded LCP film obtained as described above is subjected to a stretching treatment. In this case, the stretching treatment is preferably performed in the form of a laminate in which a synthetic resin film is laminated on both sides of the LCP film. FIG. 1 shows a cross-sectional configuration diagram of the laminate film of the LCP film. In FIG. 1, A indicates an LCP film composed of LCP, and most of the LCP is oriented in one direction. On the other hand, B-1 and B-
Reference numeral 2 denotes a synthetic resin film (hereinafter, also simply referred to as a resin film). The resin films B-1 and B-2 can be the same or different.

In the laminated film shown in FIG.
It is necessary that the melting point of the CP film A is lower than the melting points of the resin films B-1 and B-2, preferably lower than their softening points. LCP is different from general thermoplastic resin, its molecules are rigid molecules, and because there is no entanglement of each molecule,
If the stretching is performed at a temperature lower than the liquid crystal transition temperature, the molecules cannot be stretched, and the stretching cannot be performed smoothly. 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, it is very difficult for the LCP film to be stretched smoothly as it is. However, in the form of a laminate with a resin film as shown in FIG. 1, even if the LCP film A is melted, this melt is formed by the unmelted resin films B-1 and B-2. Is held, so that stretching is possible.

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 LCP film, the film only weakly bonds to the LCP film, so that the films can be easily peeled after stretching and cooling. The peel strength of the nonporous film in this case is smaller than 500 g / cm, usually 1 to 500 g / cm, preferably 2 to 500 g / cm.
It is about 100 g / cm. Hereinafter, an isotropic LCP including a laminate forming step of forming such a laminate film
The method for producing the 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 film B-1 is applied to both surfaces of the LCP film A.
And B-2 are each subjected to thermocompression bonding to form a laminate. The thermocompression bonding temperature is as follows:
-2 do not substantially melt, but at least the surface portion of the LCP film A, ie, the nonporous films B-1 and B-1
-2 is a temperature for softening only or the entire surface of the film A in contact with -2. The thickness of the LCP film A is not particularly limited, but is usually 20 μm to 5 mm, preferably 5 μm.
0 to 800 μm, more preferably 80 to 200 μm
It is. The thickness of the nonporous film to be thermocompression-bonded to both surfaces is not particularly limited, but is usually 10 to 200 μm.
m, preferably 20 to 100 μm.

In order to 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 LCP film A under pressure and heat, respectively, and at least the surface is softened. The nonporous films B-1 and B-2 are thermocompression-bonded to the LCP film A in the state as described above. In this case, the liquid crystal polymer film A is sandwiched between the two non-porous films B-1 and B-2 from both sides. Good. By such thermocompression bonding, LC
Non-porous films B-1 and B-
2 are weakly joined to form a laminate.

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, the LCP film A and the two non-porous films B-1 and B-2 are placed in a gap between the pair of thermocompression bonding rolls 1 (Clear). Lance) and thermocompression-bonded in the gap between the thermocompression rolls. In this case, the nonporous films B-1 and B-2 are supplied to both sides of the LCP film A. The LCP 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 device, a first non-porous film is laid on the bottom plate of the hot press device, and L
The CP film is stacked, the second non-porous film is stacked thereon, and the top plate is pressed from above and thermocompressed for a predetermined time,
Cooling. In this case, the bottom plate and / or the top plate is heated and L
At least the surface of the CP film is softened. 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 temperature at which the LCP film is softened or melted without substantially melting the nonporous film of the laminated film obtained in the above-mentioned laminated film forming step is softened. Under the conditions, the film is stretched uniaxially or biaxially. That is, while stretching in the direction (TD) perpendicular to the orientation direction of the liquid crystal polymer or stretching in the same direction (MD) as the orientation of the liquid crystal polymer,
That is the step of stretching in the vertical direction (TD). In this case, the stretching ratio to MD is 1 to 10 times, preferably 1 to 10 times.
The stretching ratio to TD is 1.5 to 20 times, and preferably 3 to 15 times. The stretching ratio to TD is
1.0 to 5.0 times, preferably 1.times.
It is better to specify 5 to 3.0 times. Stretching speed is 20
% / Sec or more, preferably 20 to 100% / sec, more preferably 20 to 50% / sec. Also,
In the case of the present invention, biaxial stretching is preferred. As the stretching device, a conventionally known stretching device can be used.

(Cooling step) In this step, the stretched laminate film obtained in the stretching step is cooled, and the L
This is a step of cooling and solidifying the CP film, and can be performed using a pair of cooling rolls. In addition, it can be performed by natural cooling.

(Peeling Step) This step is a step of peeling the nonporous film thermocompression-bonded to both surfaces from the laminated film obtained in the cooling step. As described above, since the non-porous film is peelably and weakly bonded to the LCP film, the non-porous film is easily peeled by pulling it upward from the LCP film. be able to.

As described above, an isotropic LCP film can be obtained. This is excellent in isotropic properties of planar physical properties and extremely excellent in usability. The thickness of the film is usually 10 to 300 μm, preferably 25 to 125 μm, but if necessary, it can be further reduced by adjusting the stretching ratio.

In the laminated film shown in FIG. 1, both the resin films B-1 and B-2 can be porous films. LC for porous film
In the case of thermocompression bonding on both sides of a P film, if the compression force at the time of thermocompression is weak, the porous material film is LCP
Since the film is weakly bonded to the film, the film can be easily peeled after stretching and cooling. The peel strength of the porous film in this case is 500
It is preferably smaller than g / cm, usually about 1 to 500 g / cm, preferably about 2 to 100 g / cm. The method for producing an isotropic LCP film including the step of forming such a laminate film is performed by sequentially performing a stretching step, a cooling step, and a peeling step after forming the laminate film in the same manner as described above. You.

When a porous film is thermocompression-bonded to both sides of an LCP film, if the compression force is increased during the thermocompression bonding, the porous film is strongly bonded to the LCP film, so that the stretching and stretching can be performed. Even after cooling, the films do not peel off easily. Therefore, when such a laminate film is used, the isotropic LC
A laminate product in which the porous film is strongly bonded to both sides of the P film can be produced. In this case, the peel strength of the porous film is 0.5 kg / cm or more, and is usually set to 1 kg / cm or more, preferably 1.2 kg / cm or more. The method for producing an isotropic LCP film laminate including the step of forming such a laminate film is performed by sequentially performing a stretching step and a cooling step after forming the laminate film in the same manner as described above. . According to this method, an isotropic LCP film in which a porous film is firmly bonded to both surfaces can be obtained.

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 thermocompression-bonded to the LCP film, if the pressing force at the time of thermocompression is increased, the porous body film is firmly bonded to the LCP film, so even after stretching and cooling, The film cannot be easily peeled. In this case, the peel strength of the porous film is 0.5 kg / cm or more, usually 1 kg / cm or more, preferably 1.2 kg / cm.
cm or more. On the other hand, when the nonporous film is thermocompression-bonded to the LCP film, the nonporous film is weakly bonded to the film, even if the compression force is strong in the thermocompression, so that stretching and stretching can be performed. After cooling, the film can be easily peeled off.
The peel strength of the nonporous film in this case was 500 g /
cm, usually about 1 to 500 g / cm, preferably about 2 to 100 g / cm. Isotropic LC including the step of forming such a laminate film
The method for producing a P film is as follows:
In the same manner as described above, the stretching step, the cooling step, and the peeling step are sequentially performed. In this case, in the peeling step, only the nonporous film is peeled. By this method, an isotropic LCP film in which the porous film is firmly bonded only on one side is obtained.

In the present invention, the raw material LCP film comprises an LCP extruded film containing a filler, the filler has an average particle size of 0.01 to 50 μm, and the content of the filler is 5 to 30% by volume,
Further, an LCP in which the ratio D / C of the standard deviation D of the thickness distribution to the average value C of the thickness distribution of the film is 0.2 or less.
It is preferable to use a film.

In general, an anisotropic LCP film obtained by extrusion molding has an appearance like a film in which fibers are gathered, depending on the type of the LCP, and a longitudinal direction (the orientation direction of the LCP). ) (MD), many vertical streaks are seen, and the horizontal direction (direction perpendicular to the orientation direction (T
D) has a very uneven thickness. Further, such a surface state observed in an extruded film of LCP is represented by LCP
This also occurs in the case of an extruded film of a liquid crystal polymer alloy obtained by alloying CP with another thermoplastic polymer. The LCP film having such a surface state is very difficult to use, and its use has been severely restricted. On the other hand, the anisotropic LCP film containing the above-mentioned filler is used as a raw material film, and the isotropic film obtained by stretching the same has a uniform thickness and a very good surface property. The ratio D / C of the standard deviation D of the thickness distribution to the average value C of the thickness distribution of the film is 0.2 or less, preferably 0.1 or less, particularly in the range of 0.01 to 0.05.

In order to obtain a raw material LCP film containing a filler, the filler is added to the LCP, melt-mixed, and the resulting mixture is extruded into a film through a T-die or an inflation die at the tip of the extruder. 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 20 μm to 5 mm, preferably 50 to 800 μm. The extruded film thus obtained is
Although the film is an anisotropic film, it is a film having a good surface condition, and the ratio D / C of the standard deviation D of the thickness distribution to the average value C of the thickness distribution of the film is 0.2 or less, and in particular, 0. 05 or less. Also, the surface roughness R of this film
z is 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 LCP, carbon, graphite, carbon fiber, and the like. Examples of the heat-resistant resin powder include polyimide, polyetherimide, polyamideimide, polyetheretherketone (PEEK), and fluororesin (P
TFE, FEP, PFA, ETFE, CTFE, PVD
F, E-CTFE, etc.) and heat-resistant LCP.
The filler has an average particle size of 0.01 to 50 μm.
m, preferably 0.1 to 10 μm. The content of the filler in the LCP containing the filler is 5 to 30.
% By volume, preferably 10 to 20% by volume. If the content of the filler is more than the above range, the properties of the LCP 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 LCP film according to the present invention has a LC
The molecules of P are randomly oriented in the plane direction, and the one-dimensional property of the LCP film, which is different from that of a normal LCP film, is eliminated. In this case, the planar properties include a coefficient of linear expansion, a coefficient of thermal expansion,
Thermal shrinkage, tensile elongation, tensile strength, tensile elasticity, and the like are included. The isotropic LCP film of the present invention has, in particular, a reduced coefficient of linear expansion and a reduced thermal shrinkage that could not be achieved with conventional LCP films, while having an increased tensile modulus. That is, the LCP film of the present invention has a linear expansion coefficient of 20 ppm / ° C. or less, preferably 10 ppm / ° C. or less, more preferably 7 ppm /% or less. The lower limit of the linear expansion coefficient is usually
It is about 3 ppm / ° C. Further, the LCP film of the present invention has a heat shrinkage of 0.05% or less, preferably 0.03% or less. The lower limit of the heat shrinkage is usually -0.0.
It is about 05%. The LCP film of the present invention has a thickness of 600
kg / mm ² or more, preferably 1000 kg / mm ² or more. The upper limit of the tensile modulus is usually about 1500 kg / mm ² .

The LCP film of the present invention has a linear expansion coefficient excellent in the isotropic direction, and a ratio A between a linear expansion coefficient A in one plane direction and a linear expansion coefficient B in another direction of the film.
/ B is in the range of 0.3 to 3, preferably 0.5 to 2. When the LCP film is used as a film material for electronic parts, for example, as an interposer for mounting an IC chip or a wiring board, the isotropic property of the linear expansion coefficient is very important. Otherwise, reliable electronic materials and products cannot be obtained. The LCP film of the present invention is advantageously used as a film material for electronic components, particularly as an interposer for an IC chip, a TAB substrate, an ASIC, an MCM, and the like.

The filler-containing LCP film according to the present invention is excellent in surface condition and has a smooth surface, and the ratio D / D of the standard deviation D of the thickness distribution to the average value C of the thickness distribution.
C is 0.2 or less, preferably 0.15 or less, more preferably 0.1 or less. Further, the film surface roughness R _Z is 10 μm or less, preferably 5 μm or less.
The lower limit is usually about 1 μm.

The LCP film of the present invention includes, in addition to an LCP film having no other synthetic resin film laminated thereon, a laminated film having a synthetic resin film laminated on both surfaces thereof, and a synthetic resin laminated on one surface thereof. Laminated film is included. These LCP films can be widely used in the fields of electric / electronic parts, packaging, etc. based on their excellent heat resistance, mechanical strength, electric properties, gas barrier properties, chemical stability and the like.

[0033]

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

Example 1 A thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) was fed into a single screw extruder (screw diameter 5 mm).
0 mm), extruded into a film from a T-die (lip length 300 mm, lip clearance 2.5 mm, die temperature 350 ° C.) at the tip of the extruder at a draft ratio of 10 and cooled to a thickness of 250 μm. Was obtained. On both sides of this liquid crystal polymer film, a 40 μm-thick porous polytetrafluoroethylene (PT
FE) film (average pore diameter 0.2 μm, porosity 80%)
With a pair of hot rolls (temperature 330 ° C., roll peripheral speed 2 m /
), And then cooled through a pair of cooling rolls (temperature: 150 ° C). The peel strength of the PTFE film of this laminate was 5 g / cm.
Next, the laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 350 ° C., a stretching ratio of 1.3 times in the MD direction, 3.9 times in the TD direction, and a stretching speed of 2 times.
0% / sec. Finally, the porous PTFE film was peeled off from both sides of the liquid crystal polymer film, and the thickness was 50 μm.
m of the stretched liquid crystal polymer film (a-1) was obtained.

Example 2 90 parts by weight of a thermotropic liquid crystal polymer (Sumika Super E6000 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of natural silica (average particle size: 3 μm, FS-15 manufactured by Denki Kagaku Co., Ltd.)
The mixture was melt-mixed using a twin-screw extruder, extruded from a strand die at the tip, and formed into pellets with a pelletizer. Next, this pellet was melted in a single screw extruder (screw diameter 50 mm), and a T die (lip length 300 mm, lip clearance 2.5 mm,
From a die temperature of 350 ° C.), the mixture was extruded into a film at a draft ratio of 10 and cooled to obtain a 250 μm thick liquid crystal polymer film. A porous polytetrafluoroethylene (PTFE) film having a thickness of 40 μm (average pore diameter 0.2 μm, porosity 8
0%) was thermocompression-bonded with a laminator having a pair of hot rolls (temperature: 330 ° C., roll peripheral speed: 2 m / min), and then cooled through a pair of cooling rolls (temperature: 150 ° C.). The peel strength of the PTFE film of this laminate was 5 g / cm. Next, the laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 350 ° C., a stretching ratio of 1.3 times in the MD direction, 3.9 times in the TD direction, and a stretching speed of 20% / sec. Finally, the porous PTFE film was peeled off from both sides of the liquid crystal polymer film to obtain a stretched liquid crystal polymer film (a-2) having a thickness of 50 μm.

Example 3 A thermotropic liquid crystal polymer (Vectra A950, manufactured by Polyplastics Co., Ltd.) was melted in a single screw extruder (screw diameter: 50 mm), and a T die (lip length: 300 mm, lip length) at the tip of the extruder was melted. The mixture was extruded into a sheet at a draft ratio of 10 from a clearance of 2.5 mm and a die temperature of 300 ° C.), and cooled to obtain a liquid crystal polymer film having a thickness of 250 μm. On both sides of this liquid crystal polymer film, a porous polytetrafluoroethylene (PTF) having a thickness of 40 μm is provided.
E) Film (average pore size 0.5 μm, porosity 80%)
With a pair of hot rolls (temperature 320 ° C., roll peripheral speed 2 m /
), And then cooled through a pair of cooling rolls (temperature: 100 ° C.). The peel strength of the PTFE film of this laminate was 1.5 kg / cm. Next, the laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 300 ° C., a stretching ratio of 1.6 times in the MD direction, 3.2 times in the TD direction, and a stretching speed of 20% / sec. Thus, the porous P
A stretched liquid crystal polymer film (a) in which a TFE film is laminated and adhered to both sides of a liquid crystal polymer film having a thickness of 50 μm.
-3) was obtained.

Example 4 A twin-screw extruder was used which comprises 90 parts by weight of a thermotropic liquid crystal polymer (Vectra A950, manufactured by Polyplastics) and 10 parts by weight of natural silica (average particle size: 3 μm, FS-15 manufactured by Denki Kagaku). , And extruded from a strand die at the tip to form a pelletizer into pellets. Next, the pellet is melted in a single screw extruder (screw diameter 50 mm), and a T die (lip length 300 mm, lip clearance 2.5 m) at the tip of the extruder is melted.
m, a die temperature of 300 ° C.) and extruded into a film at a draft ratio of 10 and cooled to obtain a liquid crystal polymer sheet having a thickness of 250 μm (draft ratio of 10). A porous polytetrafluoroethylene (PTFE) film having a thickness of 40 μm (average pore diameter: 0.5 μm, porosity: 80%) is provided on both sides of the liquid crystal polymer film by a pair of heat rolls (temperature: 320 ° C., roll peripheral speed: 2 m). / Min), and then cooled through a pair of cooling rolls (temperature: 100 ° C). The peel strength of the PTFE film of this laminate was 1.5 kg / cm. Next, the laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 300 ° C., a stretching ratio of 1.6 times in the MD direction,
It was 3.2 times in the TD direction and the stretching speed was 20% / sec. Thus, the porous PTFE film having a thickness of 5
A stretched liquid crystal polymer film (a-4) laminated and adhered to both sides of a 0 μm liquid crystal polymer film was obtained.

Comparative Example 1 A thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) was supplied to a single screw extruder (screw diameter: 5).
0 mm), extruded into a film from a T-die (lip length 300 mm, lip clearance 1 mm, die temperature 350 ° C.) at the tip of the extruder at a draft ratio of 4, cooled and cooled to a thickness of 250 μm. A polymer film was obtained. On both sides of this liquid crystal polymer film, a thickness of 40
μm porous polytetrafluoroethylene (PTFE)
The film (average pore size 0.2 μm, porosity 80%) is thermocompression-bonded with a laminator having a pair of hot rolls (temperature 330 ° C., roll peripheral speed 2 m / min), and then a pair of cooling rolls (temperature 150 ° C.). And cooled. PT of this laminate
The peel strength of the FE film was 5 g / cm. next,
The laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 350 ° C., a stretching ratio of 1.3 in the MD direction, 3.9 in the TD direction, and a stretching speed of 10% /
Seconds. Finally, the porous PTFE film was peeled off from both sides of the liquid crystal polymer film to obtain a stretched liquid crystal polymer film (c-1) having a thickness of 50 μm.

Comparative Example 2 A thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) was fed to a single screw extruder (screw diameter 5).
0 mm), extruded into a film from a T-die (lip length 300 mm, lip clearance 1 mm, die temperature 350 ° C.) at the tip of the extruder at a draft ratio of 4, cooled and cooled to a thickness of 250 μm. A polymer film was obtained. On both sides of this liquid crystal polymer film, a thickness of 40
μm porous polytetrafluoroethylene (PTFE)
The film (average pore diameter: 0.2 μm, porosity: 80%) is thermocompression-bonded by a laminator having a pair of hot rolls (temperature: 330 ° C., roll peripheral speed: 2 m / min), and then a pair of cooling rolls (temperature: 150 ° C.) And cooled. PT of this laminate
The peel strength of the FE film was 5 g / cm. next,
The laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time were a stretching temperature of 350 ° C., a stretching ratio of 1.3 times in the MD direction, 3.9 times in the TD direction, and a stretching speed of 20% /
Seconds. Finally, the porous PTFE film was peeled off from both sides of the liquid crystal polymer film to obtain a liquid crystal polymer stretched film (c-2) having a thickness of 50 μm.

Comparative Example 3 90 parts by weight of a thermotropic liquid crystal polymer (Sumika Super E6000 manufactured by Sumitomo Chemical Co., Ltd.) and 10 parts by weight of natural silica (average particle size: 3 μm, FS-15 manufactured by Denki Kagaku Co., Ltd.)
The mixture was melt-mixed 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), and a film is formed from a T-die (lip length: 300 mm, lip clearance: 1 mm, die temperature: 350 ° C.) at the tip of the extruder at a draft ratio of 4 The mixture was extruded into a shape and cooled to obtain a liquid crystal polymer sheet having a thickness of 250 μm (draft ratio: 4). A porous polytetrafluoroethylene (PTFE) film having a thickness of 40 μm (average pore diameter: 0.2 μm, porosity: 80%) is provided on both sides of the liquid crystal polymer film by a pair of heat rolls (temperature: 330 ° C., roll peripheral speed: 2 m). / Min), and then cooled through a pair of cooling rolls (temperature: 150 ° C). The peel strength of the PTFE film of this laminate was 5 g /
cm. Next, the laminate thus obtained was stretched by a biaxial stretching machine. The stretching conditions at this time are as follows:
0 ° C., stretching ratio MD direction 1.3 times, TD direction 3.9 times,
The stretching speed was 10% / sec. Finally, the porous P
The TFE film was peeled off from both sides of the liquid crystal polymer film, and a 50 μm thick liquid crystal polymer stretched film (c-
3) was obtained.

Comparative Example 4 A thermotropic liquid crystal polymer (Sumika Super E6000, manufactured by Sumitomo Chemical Co., Ltd.) was fed to a single screw extruder (screw diameter 5
0 mm), extruded into a film from a T-die (lip length 300 mm, lip clearance 1.0 mm, die temperature 350 ° C.) at the tip of the extruder under the conditions of a draft ratio of 20, cooled, and cooled to a thickness of 50 μm. Was obtained as a liquid crystal polymer film (c-4).

The physical properties of each of the liquid crystal polymer films obtained as described above were measured as follows, and the results are shown in Table 1. (1) TD thickness distribution A needle-type measuring element of a dial gauge (manufactured by Mitutoyo Corporation, tip R: 0.4 mm) is vertically opposed and fixed, and is contacted with a force of 100 g. Next, a sample film is sandwiched between the probes and moved in the TD direction. In this way, TD thickness distribution data of the film is obtained. (I) Average value C 2000 points were measured at 1000 mm width and 0.5 mm interval, and the average value was obtained. (Ii) Standard deviation D A standard deviation D of 2000 points with respect to the average value C was obtained. (2) Surface roughness Rz Measured according to JIS B0601. in this case,
Surfcom 150 manufactured by Tokyo Seimitsu Co., Ltd.
OA was used. (3) Linear expansion coefficient TMA method: Measured at a load of 5 g, after the temperature was raised to 200 ° C., and when the temperature was lowered from 150 ° C. to 25 ° C. Sample width 4.0 mm, chuck interval 10 mm. (4) Heat Shrinkage The film is cut into a square of 100 mm, and the coordinates of the corners are measured with an optical three-dimensional measuring device in units of 0.1 μm. Next, the film is left in a thermostat at 200 ° C. for 2 hours and then taken out. Similarly, the coordinates of the corners are measured, and the heat shrinkage of MD and TD is measured from the measured values before and after the heat treatment. (5) Tensile modulus JIS K 7127 Type 2 test piece Tensile speed 50 mm / min

[0043]

[Table 1]

[0044]

According to the LCP film of the present invention, the liquid crystal polymer molecules are randomly oriented in the plane direction, and the anisotropy of the plane physical properties is eliminated. It has a high coefficient of linear expansion and a high heat shrinkage, as well as an enhanced tensile modulus. The LCP film of the present invention, in the form of an unlaminated film or a laminated film, is advantageously used in the fields of electric / electronic materials and packaging materials.

[Brief description of the drawings]

FIG. 1 is a fragmentary 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 porous film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B29K 67:00 B29L 7:00

Claims (4)

[Claims] An isotropic liquid crystal polymer film in which liquid crystal polymer molecules composed of a thermotropic liquid crystal polymer or a polymer alloy thereof are randomly oriented in a plane direction, and the film has a linear expansion coefficient of 20 ppm in an arbitrary plane direction. / ° C or less, heat shrinkage rate of 0.05% or less, tensile modulus of elasticity of 600 kg / mm ² or more, and the ratio A / of the linear expansion coefficient A in one plane direction to the linear expansion coefficient B in the other plane direction. A liquid crystal polymer film wherein B is in the range of 0.3 to 3. 2. An isotropic liquid crystal polymer film comprising a thermotropic liquid crystal polymer or a polymer alloy thereof, and liquid crystal polymer molecules containing 5 to 30% by volume of a filler are randomly oriented in a plane direction. Has a linear expansion coefficient of 20 ppm / ° C. in an arbitrary plane direction.
Below, the heat shrinkage is 0.1% or less and the tensile elasticity is 60 or less.
0 kg / mm ² or more, and the ratio A / B of the linear expansion coefficient A in one plane direction to the linear expansion coefficient B in the other plane direction is 0.
And the ratio D / C of the standard deviation D of the thickness distribution to the average value C of the thickness distribution of the film is in the range of 3 to 3.
A liquid crystal polymer film having a film surface roughness R _Z of 10 μm or less. 3. A liquid crystal polymer film laminate in which a synthetic resin film is laminated and bonded to both surfaces or one surface of the liquid crystal polymer film according to claim 1. 4. The liquid crystal polymer film laminate according to claim 3, wherein said synthetic resin film is a fluororesin porous film.