JPS63270760A - Liquid crystal film - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal film excellent in mechanical strengths, surface smoothness, dimensional stability and moldability into thin film, by mixing a specified non-wholly aromatic polyester resin with a polycarbonate resin at a mixing ratio in a specified range and forming the resulting mixture into a film. CONSTITUTION:A liquid crystal film obtained by stretching a resin film containing 2-50wt.% non-wholly aromatic polyester resin comprising 9-42mol.% structural units of formula I (wherein R1 is H, a halogen or a 1-4C alkyl or alkoxyl), 9-42mol.% structural units of formula II (wherein n is 1-20) and 16-82mol.% structural units of formula III (wherein R2 is R1) and 98-50wt.% polycarbonate resin at a draft ratio of 1.2-500. This film is excellent in mechanical strengths, surface smoothness, dimensional stability, moldability into thin film, etc. and is suitable for capacitors, food packaging, etc.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a liquid crystal film, and more specifically, the present invention relates to a liquid crystal film that is used for condensers, food packaging, etc. This invention relates to a liquid crystal film with excellent stability, thin film formability, etc.

[Conventional technology]

Since liquid crystalline film has excellent mechanical properties, chemical stability, and dimensional stability, its application to various films such as electrical insulating materials, magnetic recording tapes, photographic films, and drafting films is being considered.

Conventionally, liquid crystalline polyester films have been manufactured by extrusion using a T-die or the like. However, in this method, when the molten liquid crystalline polyester resin passes through the slit of the die, the molecules tend to be oriented in the extrusion direction. Although it exhibits a high modulus of elasticity, it has the disadvantage that both tear strength and modulus of elasticity are extremely low in the direction perpendicular to this (TD force direction). I couldn't escape it.

Therefore, as a method to improve such drawbacks, a method has been proposed, for example, of biaxially stretching a polyester resin that exhibits optical anisotropy in a molten state (Japanese Patent Laid-Open No. 55-12342).
Publication No. 7). However, this method has the disadvantage that it is difficult to produce a film of uniform quality, and the resulting film has insufficient tensile strength and dimensional stability.

On the other hand, polycarbonate films manufactured by the solution casting method have excellent electrical properties and heat resistance, and are used for capacitors, etc., but they have the drawbacks of low productivity and low strength, and the T-die method makes it difficult to make thin films. The disadvantage was that it was difficult.

Compositions consisting of fully aromatic polyester resins and polycarbonate resins are also known (Japanese Patent Application Laid-Open No. 57-4055).
No. 1), the molding temperature was high, the molding stability was insufficient, and when formed into a film, it was brittle and impractical.

In addition, 55 to 90% by weight of incompletely aromatic polyester resin
A composition suitable as a coating material for optical fibers consisting of 10 to 45% by weight of polycanibonate resin is also known (Japanese Unexamined Patent Publication No. 62-59662), but this composition has a low tear strength when used for films. However, the surface smoothness was insufficient.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a liquid crystalline film having excellent mechanical strength, surface smoothness, dimensional stability, and thin film formability.

[Means for solving problems]

As a result of extensive research in order to achieve the above object, the present inventors have found that by forming a resin film obtained by blending a polyester resin with a specific structure and a polycarbonate resin in a specific range under specific conditions. The inventors have found a way to achieve this objective, and have completed the present invention based on this knowledge.

That is, the present invention produces a resin film containing 2 to 50% by weight of the following specific incompletely aromatic polyester resin (A) and 98 to 50% by weight of a polycarbonate resin at a draft ratio of 1.2 to 500. The present invention relates to a liquid crystalline film characterized by having a film.

Incompletely aromatic polyester resin (A
) consists of predetermined amounts of structural unit [I], structural unit (II), and structural unit (III) represented by the following formula.

P.

(In the formula, R5 is a hydrogen atom, a halogen atom, or a carbon number 1
~4 alkyl group or alkoxy group) Structural unit (n) -04-C11゜-CH□→1-0
- (In the formula, n represents an integer of 1 to 20) 9 to 42 mol% (In the formula, R2 represents the same meaning as R above) 16 to 82
Mol% Here, the incomplete polycarbonate resin means a polyester resin in which all of the structural units present in the polyester do not have aromatic rings. That is, structural unit (II) does not have an aromatic ring. Further, the structural units (1) to (I[I) are randomly bonded.

R3 of the structural unit (I) may be any of those listed above, and among them, hydrogen atom, chlorine atom, fluorine atom,
Methyl, ethyl, methoxy, ethoxy, phenoxy and naphthoxy groups are preferred. Structural unit [11]
n is an integer of 1 to 20, preferably an integer of 1 to 4. Similarly to R3, R2 of the structural unit CDI) may be any of those listed above, but like R1, particularly hydrogen atom, chlorine atom, fluorine atom, methyl group, ethyl group, methoxy group. , ethoxy group, phenoxy group and naphthoxy group are preferred. These structural units [I]
, (If), ([1) is the most suitable combination.

In addition, the contents of structural units (1), (II), and (III) are set to be 9 to 42 mol%, 9 to 42 mol%, and 16 to 82 mol%, respectively, and a total of 100 mol%. do. Among these, the particularly important one is the structural unit (
When the content of III) is less than 16 mol%, the aromatic polyester does not form a liquid crystal,
On the other hand, if it exceeds 82 mol%, although liquid crystals can be formed, the moldability deteriorates, which is not preferable. Furthermore, this aromatic polyester is added to 100 ml of a mixed solution of phenol and tetrachloroethane (volume ratio 3:2).
．． The logarithmic viscosity of the solution obtained by dissolving 5 g at 30° C. is preferably 0.4 to 3.0, particularly preferably 0.5 to 1.5. The aromatic polyester may be prepared by a conventional method, or a commercially available product such as X7G manufactured by Eastman Kodak Company may be used.

Next, the polycarbonate resin used in the present invention has the following formula: , SO-OSCO or Cuff CH,1 or a bromine atom or a saturated alkyl group having 1 to 8 carbon atoms, m represents a number of 0 to 4.) A polymer having a structural unit represented by It is.

This polycarbonate resin is prepared by a solvent process, i.e., by the reaction of a dihydric phenol with a carbonate precursor such as phosgene, or by the reaction of a dihydric phenol with a carbonate precursor such as phosgene in the presence of a known acid acceptor, the molecule ffHJ1 regulator, in a solvent such as methylene chloride. It can be produced by transesterification with carbonate precursors such as diphenyl carbonate.

Here, dihydric phenols that can be suitably used include bisphenols, and 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) is particularly preferred. Further, part or all of bisphenol A may be substituted with other dihydric phenol. Examples of dihydric phenols other than bisphenol A include hydroquinone, 4,4'-dihydroxydiphenyl, bis(4
-hydroxyphenyl)alkane, bis(4-hydroxyphenyl)cycloalkane, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxyphenyl)
Compounds such as sulfoxide, bis(4-hydroxyphenyl) ether or bis(3,5-dibromo-4-
Mention may be made of halogenated bisphenols such as hydroxyphenyl)propane and bis(3,5-dichloro-4-hydroxyphenyl)propane. These dihydric phenols may be homopolymers of dihydric phenols or copolymers or blends of two or more dihydric phenols. Furthermore, the polycarbonate resin used in the present invention may be a thermoplastic randomly branched polycarbonate obtained by reacting a polyfunctional aromatic compound with a dihydric phenol and/or a carbonate precursor.

In terms of mechanical strength and moldability, the polycarbonate resin used in the present invention has a viscosity average molecular weight of 10,
000~so, ooo is preferable, especially 18,0
00 to 35,000 is suitable.

The liquid crystalline film of the present invention is obtained by forming a resin film obtained by blending the essential components of the incompletely aromatic polyester resin (A) and the polycarbonate resin (B). The mixing ratio of component (A) and component (B) is 2 to 50% by weight of component (A) and 98 to 50% by weight of component (B). If the content of component (A) is less than 2% by weight, the tensile strength will decrease, and if it exceeds 50% by weight, the tear strength and surface smoothness will decrease, which is not preferable. A preferred blending ratio is 3 to 40% by weight of component (A) and 97 to 60% by weight of component (B).

In the present invention, the resin film may be mixed with various fillers and additives as desired to form a film. Examples of various fillers include glass fiber, asbestos, carbon fiber, amorphous carbon fiber, synthetic polymer fiber, aluminum fiber, aluminum silicate fiber, aluminum oxide fiber, titanium fiber, magnesium fiber, rock wool fiber, and steel. Fibers such as tungsten fibers, cotton, wool, and sheep wool cellulose fibers, or calcium silicate, silica, clay, talc, mica, polytetrachloroethylene, graphite, aluminum trihydrate, storium aluminum carbonate, barium ferrite. Examples include.

Among these, preferred are those with an average particle size of 0. O1~1
Mention may be made of 0μ silica, talc, and clay.

Sliding properties can be improved by adding 0.005 to 3 Offl parts of these fillers to 100 parts by weight of the film composition.

Furthermore, examples of various additives include antioxidants, ultraviolet absorbers, pigments, dyes, plasticizers, and antistatic agents.

In order to obtain the liquid crystalline film of the present invention, a resin composition containing the components (A) and (B), or various fillers, additives, etc. that are blended with this resin composition as desired, is melted from a die. A resin film is manufactured by extruding and taking it off with a cooling roll. Here, the above-mentioned resin composition is manufactured by blending each component after drying and melt-kneading.

For this kneading process, dry-wet method, combined melt-mixing method, multi-stage melt-mixing method, simple melt-mixing method, etc. can be applied. A mixer, Henschel mixer, etc. can be used.

Next, the desired liquid crystalline film is obtained by forming this resin film at a specific draft ratio.

A method for manufacturing a liquid crystal film will be explained according to the attached drawings. The figure is a schematic diagram for explaining one example of the manufacturing method (when using an air knife), and the resin composition is melted at a melting temperature of 220 to 350°C, preferably 23°C, from a T-die 1.
Melt extrusion is carried out in the range of 0 to 320°C. This temperature is 2
Below 20°C, the melt viscosity is high and orientation tends to proceed (<, while above 350°C, the resin tends to decompose and alignment becomes difficult to proceed. Regarding the position of the T-die, the height of lip 3 is high enough to prevent the molten resin from advancing). It is preferable that the sagging length) is in the range of 1 to 100 fins, particularly 1 to 60 fins. This height is 1
If it exceeds 0.00 am, the neck-in will become significant and the orientation will become worse.
A dragon, especially a range of 0.1 to 3 dragons is preferred. If this opening exceeds 5 1, the orientation will be difficult to proceed, which is not preferable.

Was it extruded from T-die 1 in this way? The molten film 4 is blown with a thin linear air stream at high speed by an air knife 5, pressed against the cooling roll 2, cooled, and taken off. The air knife has the role of improving the contact between the molten film 4 and the cooling roll 2, increasing the cooling effect, and improving the orientation of the film. The position of the air knife, the cooling conditions, etc. are appropriately selected depending on factors such as the physical properties of the film, its thickness, take-up speed, and the position of the T-die. The lip 6 of the air knife is connected to the cooling roll 2 to 1.
It is preferable to be located at a distance of ~100 degrees, especially 5 to 50 degrees. If this distance is less than 1 dragon, uniform control is difficult, and if it exceeds 100 dragons, the effect will not be sufficiently exhibited. On the other hand, the opening degree of the lip 6 is preferably in the range of 0.01 to 3 ms+, particularly 0.1 to 2 ml. Also,
The air flow velocity is preferably selected in the range of 0.5 to 70 m/sec, more preferably 5 to 60 m/sec. If this flow velocity is less than 0.5 m/sec, the effect will be small, and if it exceeds 70 m/sec, stable molding will become difficult. Also, the air pressure is 15~
A range of 5 Q mm11H is preferred. Further, the air stream is preferably blown horizontally to 10' downwardly at or slightly downstream of the line of contact between the molten film and the chill roll.

On the other hand, the temperature of the cooling roll 2 is 10-160°C, especially 20°C.
The temperature is preferably in the range of ~150°C, and in order to obtain the liquid crystalline film of the present invention, the draft ratio, that is, the ratio of the extrusion speed of the molten resin/the take-up speed of the film, is preferably in the range of 1.2 to 150°C.
It needs to be 500.

If the draft ratio is less than 1.2, orientation will be difficult to proceed, and if it exceeds 500, stable molding will be difficult, which is not preferred. The preferred range of draft ratio is 1.5-300.

An example has been described above in which a molten film is pressed against a cooling roll using air pressure using an air knife, but instead of such pneumatic pressing, an electrostatic pressing method may be used. Methods for this electrostatic pressing include the electrostatic tip probe method and the electrostatic wire pressing method.
The electrostatic wire pressing method is suitable. In the electrostatic wire pressing method, a method is usually used in which a stainless steel wire is stretched parallel to the cooling roll at a position 1 to 10 degrees away and a DC voltage of about 1 to 5 KV is applied to this wire. . This electrostatic pressing method can also be used in combination with the pneumatic pressing method described above.

Furthermore, an air chamber (a device that blows a wide air stream) may be provided below the air knife to improve the pressing and cooling effect of the film.

In this way, a high-quality, highly oriented film with little neck-in and no thickness unevenness can be obtained, but this film can be stretched as desired by conventional stretching methods such as tenter method, tubular method, and multi-stage stretching. The film may be stretched in the machine axis direction (MD force direction or in the direction perpendicular to the machine axis (TD force direction), or biaxially stretched in the machine axis direction and in the direction perpendicular to the machine axis. Good.The stretching temperature is usually in the range of 50 to 250°C, preferably 70 to 130°C.The stretching ratio is -axial stretching (TD
In the case of force direction or MD force direction, usually 1.5 to 8 times,
Biaxial stretching (usually 1 for TD force direction and MD force direction)
．． Selected in the range of 2 to 6 times. In this way, the stretched film can be heat treated as required. This heat treatment is usually carried out by heating the stretched film as it is or while subjecting it to limited shrinkage or elongation, preferably at a temperature in the range of 150 to 300° C. for about 1 second to 10 minutes. This heat treatment improves the crystallinity of the film, resulting in even better heat resistance and dimensional stability.

Furthermore, two or more films obtained by the method of the present invention can be joined together and used as a laminate. In this case, at least two sheets have extrusion directions of 30"
It is preferable to laminate the layers so that they intersect. As the lamination method, conventionally used methods such as a method using heat, a method using ultrasonic waves, a method using corona discharge,
A method using an adhesive can be used.

Since the film of the present invention has excellent mechanical strength, it can be made thinner than conventional products for the same strength. Furthermore, since it has excellent electrical properties, it is suitably used as a film for capacitors.

That is, the size of the capacitor is proportional to the square of the thickness of the film of dielectric material and inversely proportional to the dielectric constant of the dielectric material. Therefore, when the film of the present invention is used, the capacitor is considerably smaller than other capacitors even with the same capacitance.

Furthermore, the film of the present invention has excellent mechanical strength, gas barrier properties, and transparency, and is therefore suitable as a film for food packaging.

Furthermore, the film of the present invention has excellent dimensional stability and surface smoothness, so it can be used for magnetic tapes, printed circuit boards, etc.
It is also suitable for insulation, optics, acoustic vibration, drafting, and polarizing films.

〔Example〕

EXAMPLES Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

Example 1 10 parts by weight of polyester resin (PH860), 90 parts by weight of polycarbonate resin (A 2200), and 0.1 part by weight of silica with an average particle size of 0.5μ were dried and pelletized using a twin-screw extruder. .

Next, the obtained pellets were supplied to a 30mm φ-shaft extruder and extruded through a rIJ200 fin T-die under the conditions of a die temperature of 280°C, a lip opening of 11m, and an air gap of 20mm, and then extruded using a cast roll. A film having a thickness of 400 μm was obtained by taking it off (draft ratio 2.5).

The test results of the obtained film are shown in Table 1.

Examples 2 to 14, Comparative Examples 1 to 5 The same procedure as in Example 1 was conducted except for the conditions shown in Table 1.

The following polyester resins and polycarbonate resins were used as component (A), and the test method was as follows.

(A) Polyester resin PHB60: Structural unit (1) 40 mol% to logarithmic dust number 1
．． 0 (n) 40 mol% (I[1) 60 mol% PHB80: Structural unit (1) 20 mol% (n) 20 mol% (I[1) 80 mol% [[[] -]0-CIl□- cuz-o
B) Polycarbonate resin A2200: Idemitsu Petrochemical side product name “TAFLON A2”
200J viscosity average molecular weight 20,500A3000: Manufactured by Idemitsu Petrochemical 011, trade name "Taflon A3000J"
Viscosity average molecular weight 28,000*l: 4-oxybenzoyl unit 40 mol%, ■, 2-ethylenedioxy-4
．． Consisting of 15 mol% of 4'-dibenzoyl units, 15 mol% of terephthaloyl units, and 30 mol% of methyl-substituted 1,4-dioxyphenylene units, viscosity average molecular weight 28,000 Film thickness unevenness: Thickness unevenness within 10 m of film, surface smoothness Properties: center line average roughness tensile modulus, tensile strength at break: J Is-2318
Based on Elmendorf tear strength: Based on JIS-Z-1702 Coefficient of linear expansion: Using a thermal analysis device manufactured by Seiko Electronics,
Measured at temperatures ranging from -100 to 100℃, 0 to 50℃
The values at temperatures in the range of were adopted.

Sample length is 20×511, heating rate is 4℃/min
, the load was 1 g.

Volume resistivity: Permittivity based on JI 5-C-2318, Inductive loss: Manufactured by Yokogawa Hule Sotobackard Co., Ltd., L
Using F impedance analyzer, room temperature 23℃, humidity 50%, film thickness 6μ Oxygen permeability: 23
Measured at ℃, 0% RH, converted to 25μ [Effects of the invention] The liquid crystalline film obtained by the present invention has mechanical strength,
It has excellent surface smoothness and dimensional stability, can be easily made thin, and has excellent gas barrier properties and electrical properties, so it is suitably used for various purposes.

[Brief explanation of drawings]

The figure is a schematic diagram for explaining one example of the method for manufacturing the film of the present invention, in which reference numeral 1 is a T-die, 2 is a cooling roll, 3 is a lip of the T-die, 4 is a molten film, 5 is a is an air knife, and 6 is the lip of the air knife.

Claims (1)

[Claims] 1. The following incompletely aromatic polyester resin (A) 2-50
% by weight and a resin film containing 98 to 50% by weight of polycarbonate resin at a draft ratio of 1.2 to 500.
A liquid crystalline film characterized by being formed with. (A) Incomplete aromatic polyester resin structural unit [I] consisting of a predetermined amount of structural unit [I], structural unit [II] and structural unit [III] represented by the following formula [I]▲Mathematical formula, chemical formula, table, etc. Yes▼9
~42 mol% (In the formula, R_1 represents a hydrogen atom, a halogen atom, or an alkyl group or alkoxy group having 1 to 4 carbon atoms) Structural unit [II] ▲ Numerical formula, chemical formula, table, etc. are available ▼ 9 to 42 mol% (In the formula, n represents an integer from 1 to 20) Structural unit [III] ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R_2 represents the same meaning as R_1 above) 16 ~
82 mol% 2. The liquid crystalline film according to claim 1, wherein the liquid crystalline film is a liquid crystalline film for a capacitor. 3. The liquid crystalline film according to claim 1, wherein the liquid crystalline film is a liquid crystalline film for food packaging. 4. The liquid crystalline film according to claim 1, wherein the liquid crystalline film is a liquid crystalline film for acoustic vibration.