JP2005290100A - Liquid crystal polyester solution, manufacturing process therefor and liquid crystal polyester film obtained by the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare a liquid crystal polyester solution having a better productivity, a manufacturing process therefor and a liquid crystal polyester film having a better productivity. <P>SOLUTION: The liquid crystal polyester solution is obtained by dissolving 0.5-100 pts.wt. of a liquid crystal polyester in 100 pts.wt. of a solvent described below in an atmosphere with an oxygen concentration of ≤5% at a temperature of ≥140°C and ≤200°C. The manufacturing process for the liquid crystal polyester solution comprises dissolving 0.5-100 pts.wt. of the liquid crystal polyester in 100 pts.wt. of a solvent described below in an atmosphere with the oxygen concentration of ≤5% at the temperature of ≥140°C and ≤200°C. The solvent contains a halogen-substituted phenolic compound expressed by formula (I) (wherein, A is a halogen atom or a trihalogenated methyl group; (i) is an integer of 1-5; and when (i) is ≥2, A's may be different from each other or the same). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal polyester solution, a method for producing the same, and a liquid crystal polyester film obtained therefrom.

Liquid crystal polyesters are widely used mainly for precision electronic parts such as connectors obtained by injection molding because they exhibit excellent low moisture absorption, high frequency characteristics, heat resistance, and mechanical strength. In recent years, it has been studied that liquid crystalline polyester is formed into a film by extrusion molding such as T-die molding or inflation molding and used as an insulating film of a multilayer printed board or a flexible printed board.
However, the conventional liquid crystal polyester film obtained by extrusion molding has a large anisotropy at the time of molding, the tensile strength in the direction perpendicular to the flow direction at the time of molding is very weak, and damage occurs during the handling of the film. was there.
As a method for solving this problem, there is known a liquid crystal polyester film obtained by casting a solution containing a liquid crystal polyester and a solvent containing a halogen-substituted phenol and then removing the solvent (Patent Document 1). ).

JP 2002-114894 A

  In order to produce a film obtained by the method described in Patent Document 1, the liquid crystalline polyester must be dissolved in the solvent for a long time, leaving room for improvement in terms of productivity. An object of the present invention is to provide a liquid crystalline polyester solution with higher productivity, a method for producing the same, and a liquid crystal polyester film with higher productivity.

（式中、Ａはハロゲン原子またはトリハロゲン化メチル基を表わし、ｉはＡの個数であって１〜５の整数を表わし、ｉが２以上の場合に複数あるＡは互いに同一でも異なっていてもよい。） That is, the present invention provides a liquid crystal polyester obtained by dissolving 0.5 to 100 parts by weight of a liquid crystal polyester in an atmosphere having an oxygen concentration of 5% or less at a temperature of 140 ° C. or more and 200 ° C. or less with respect to 100 parts by weight of the following solvent. The present invention relates to a solution, and the present invention relates to 0.5 to 100 parts by weight of a liquid crystalline polyester at a temperature of 140 ° C. or more and 200 ° C. or less in an atmosphere having an oxygen concentration of 5% or less with respect to 100 parts by weight of the following solvent. This relates to a method for producing a liquid crystal polyester solution to be dissolved. The present invention relates to a liquid crystal polyester film obtained from the liquid crystal polyester solution.
Solvent: A solvent containing a halogen-substituted phenol compound represented by the following general formula (I).

(In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents the number of A and represents an integer of 1 to 5, and when i is 2 or more, a plurality of A's are the same or different from each other. May be good.)

  The liquid crystal polyester used in the present invention is a polyester called a thermotropic liquid crystal polymer, and forms a melt that exhibits optical anisotropy at a temperature of 450 ° C. or lower.

As liquid crystal polyester, for example,
(1) What is obtained by polymerizing a combination of an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol,
(2) those obtained by polymerizing different kinds of aromatic hydroxycarboxylic acids,
(3) What is obtained by polymerizing a combination of an aromatic dicarboxylic acid and an aromatic diol,
(4) Crystalline polyesters such as polyethylene terephthalate are reacted with an aromatic hydroxycarboxylic acid.
In addition, you may use those ester-forming derivatives instead of these aromatic hydroxycarboxylic acid, aromatic dicarboxylic acid, or aromatic diol.

Examples of the ester-forming derivative of carboxylic acid include those in which the carboxyl group is a highly reactive derivative such as an acid chloride or an acid anhydride that promotes the polyester formation reaction, and the carboxyl group is an ester. Examples include those that form esters with alcohols, ethylene glycol, or the like that form polyesters by an exchange reaction.
Examples of the ester-forming derivative of a phenolic hydroxyl group include those in which a phenolic hydroxyl group forms an ester with a carboxylic acid so that a polyester is produced by a transesterification reaction.

  In addition, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids and aromatic diols are halogen atoms such as chlorine atoms and fluorine atoms, alkyl groups such as methyl groups and ethyl groups, phenyl groups, and the like, as long as they do not inhibit ester formation. It may be substituted with an aryl group such as a group.

  Examples of the repeating structural unit of the liquid crystalline polyester include the following, but are not limited thereto.

上記の繰り返し構造単位は、ハロゲン原子またはアルキル基で置換されていてもよい。 Repeating structural units derived from aromatic hydroxycarboxylic acids:

The above repeating structural unit may be substituted with a halogen atom or an alkyl group.

上記の繰り返し構造単位は、ハロゲン原子、アルキル基またはアリール基で置換されていてもよい。 Repeating structural units derived from aromatic dicarboxylic acids:

The above repeating structural unit may be substituted with a halogen atom, an alkyl group or an aryl group.

上記の繰り返し構造単位は、ハロゲン原子、アルキル基またはアリール基で置換されていてもよい。 Repeating structural units derived from aromatic diols:

The above repeating structural unit may be substituted with a halogen atom, an alkyl group or an aryl group.

  In addition, as said alkyl group, a C1-C10 alkyl group is preferable and a methyl group, an ethyl group, or a butyl group is more preferable. As said aryl group, a C6-C20 aryl group is preferable and a phenyl group is more preferable.

Heat resistance, liquid crystal polyester from the balance of mechanical properties, preferably contains a repeating unit represented by A ₁ expression at least 30 mol%.
Examples of preferable combinations of repeating structural units include the following (a) to (f).
(A):
A combination of the repeating structural units (A ₁ ), (B ₂ ) and (C ₃ ),
A combination of the repeating structural units (A ₂ ), (B ₂ ) and (C ₃ ),
A combination of the repeating structural units (A ₁ ), (B ₁ ), (B ₂ ) and (C ₃ ), or
A combination of the repeating structural units (A ₂ ), (B ₁ ), (B ₂ ) and (C ₃ ).
(B): In each of the combination of said (a), by substituting a part or all of _{(C 3)} to _{(C 1)} in combination.
(C): In each of the combination of said (a), by substituting a part or all of _{(C 3)} to _{(C 2)} combined.
(D): In each of the combination of said (a), by substituting a part or all of _{(C 3)} to _{(C 4)} combinations.
(E): In each of the combination of said (a), was replaced with a mixture of _{(C 3)} of some or all the _{(C 4) (C 5)} combinations.
(F): In each of the combination of said (a), by replacing part of _{(A 1)} to (A ₂₎ in combination.

  As the liquid crystalline polyester, from the viewpoint of heat resistance, 30-80 mol% of repeating structural units derived from at least one compound selected from the group consisting of p-hydroxybenzoic acid and 2-hydroxy-6-naphthoic acid, hydroquinone and 10 to 35 mol% of repeating structural units derived from at least one compound selected from the group consisting of 4,4′-dihydroxybiphenyl, and a repeating structure derived from at least one compound selected from the group consisting of terephthalic acid and isophthalic acid The unit is preferably composed of 10 to 35 mol%.

  The weight average molecular weight of the liquid crystal polyester is not particularly limited, but is preferably 10,000 to 100,000.

  The method for producing the liquid crystal polyester used in the present invention is not particularly limited. For example, at least one selected from the group consisting of an aromatic hydroxycarboxylic acid and an aromatic diol is acylated with an excess amount of fatty acid anhydride to give an acylated product. And a method of melt polymerization by transesterifying (polycondensation) the obtained acylated product and at least one selected from the group consisting of aromatic hydroxycarboxylic acids and aromatic dicarboxylic acids. As the acylated product, a fatty acid ester obtained by acylation in advance may be used.

  In the acylation reaction, the addition amount of the fatty acid anhydride is preferably 1.0 to 1.2 times equivalent, more preferably 1.05 to 1.1 times equivalent to the phenolic hydroxyl group. If the amount of fatty acid anhydride added is small, acylated products, aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, etc. will sublimate during transesterification (polycondensation), and the reaction system tends to be clogged. The resulting liquid crystalline polyester tends to be colored significantly.

  The acylation reaction is preferably performed at 130 to 180 ° C. for 5 minutes to 10 hours, and more preferably at 135 to 150 ° C. for 1 hour to 3 hours.

  The fatty acid anhydride used in the acylation reaction is not particularly limited, and examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, anhydrous 2-ethylhexanoic acid, and monochloroacetic anhydride. , Dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, β- Examples thereof include bromopropionic acid, and two or more of these may be used in combination. From the viewpoint of price and handleability, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride is preferably used, and acetic anhydride is more preferably used.

  In the transesterification, the acyl group of the acylated product is preferably 0.8 to 1.2 times the carboxyl group.

  The transesterification is preferably performed at 130 to 400 ° C. while increasing the temperature at a rate of 0.1 to 10 ° C./min, and at 150 to 350 ° C. while increasing the temperature at a rate of 0.3 to 2 ° C./min. It is more preferable.

  When transesterifying a fatty acid ester obtained by acylation with a carboxylic acid, it is preferable to distill out the by-product fatty acid and the unreacted fatty acid anhydride by evaporating or the like in order to move the equilibrium. .

  The acylation reaction and transesterification may be performed in the presence of a catalyst. As the catalyst, those conventionally known as polyester polymerization catalysts can be used, such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, antimony trioxide and the like. And organic compound catalysts such as N, N-dimethylaminopyridine and N-methylimidazole. The catalyst is usually added when the monomers are added, and it is not always necessary to remove the catalyst after acylation. If the catalyst is not removed, transesterification can be carried out as it is.

Polycondensation by transesterification is usually performed by melt polymerization, but melt polymerization and solid phase polymerization may be used in combination. The solid phase polymerization is preferably carried out by a known solid phase polymerization method after the polymer is extracted from the melt polymerization step and then pulverized into powder or flakes. Specifically, for example, a method of heat treatment in a solid state at 20 to 350 ° C. for 1 to 30 hours under an inert atmosphere such as nitrogen can be used. Solid phase polymerization may be carried out while stirring or in a state of standing without stirring. In addition, by providing an appropriate stirring mechanism, the melt polymerization tank and the solid phase polymerization tank can be made the same reaction tank. After the solid phase polymerization, the obtained liquid crystalline polyester may be pelletized and molded by a known method.
Manufacture of liquid crystalline polyester can be performed using a batch apparatus, a continuous apparatus, etc., for example.

式中、Ａはハロゲン原子またはトリハロゲン化メチル基を表わし、ｉはＡの個数であって１〜５の整数を表わす。ｉが２以上の場合、複数あるＡは互いに同一でも異なっていてもよいが、同一であることが好ましい。
ｉは好ましくは１〜３であり、より好ましくは１または２である。ｉが１のときのＡの置換位置は４位であることが好ましく、ｉが２以上のとき少なくとも一つのＡの置換位置は４位であることが好ましい（水酸基の置換位置を１位とする）。 In the present invention, the solvent used for obtaining the liquid crystal polyester solution composition is a solvent containing a halogen-substituted phenol represented by the following general formula (I). As the solvent, a solvent containing 60% by weight or more of the halogen-substituted phenol is preferable, and it is not necessary to use 100% by weight of the halogen-substituted phenol as a solvent because it does not need to be mixed with other components. Further preferred.

In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents the number of A and an integer of 1 to 5. When i is 2 or more, a plurality of A may be the same or different from each other, but are preferably the same.
i is preferably 1 to 3, more preferably 1 or 2. The substitution position of A when i is 1 is preferably the 4-position, and when i is 2 or more, the substitution position of at least one A is preferably the 4-position (the hydroxyl substitution position is the 1-position). ).

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. A fluorine atom or a chlorine atom is preferable, and a chlorine atom is particularly preferable.
Examples of the halogen-substituted phenol represented by the general formula (I) in which the halogen atom is a fluorine atom include pentafluorophenol and tetrafluorophenol.
Examples of the halogen-substituted phenol represented by the general formula (I) in which the halogen atom is a chlorine atom include o-chlorophenol and p-chlorophenol, and p-chlorophenol is preferred from the viewpoint of solubility.

Examples of the halogen of the trihalogenated methyl group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
Examples of the halogen-substituted phenol represented by the general formula (I) in which the halogen of the trihalogenated methyl group is a fluorine atom include 3,5-bistrifluoromethylphenol.

  As the halogen-substituted phenol represented by the general formula (I), chlorine-substituted phenol compounds such as o-chlorophenol and p-chlorophenol are preferably used from the viewpoint of price and availability. From the viewpoint of solubility, p- Chlorophenol is more preferably used.

The solvent may contain other components in addition to the halogen-substituted phenol as long as the aromatic liquid crystalline polyester is not precipitated when the solution is stored or casted later.
Other components that may be contained are not particularly limited, and examples thereof include chlorine compounds such as chloroform, methylene chloride, and tetrachloroethane.

  The liquid crystal polyester solution of the present invention is obtained by dissolving 0.5 to 100 parts by weight of liquid crystal polyester with respect to 100 parts by weight of the solvent. The blending amount of the liquid crystal polyester is preferably 1 to 50 parts by weight, more preferably 5 to 15 parts by weight, based on 100 parts by weight of the solvent, from the viewpoint of workability or economy. When the blending amount is small, the production efficiency tends to decrease, and when the blending amount is too large, dissolution tends to be difficult.

  In the present invention, the liquid crystal polyester is dissolved in the solvent in an atmosphere having an oxygen concentration of 5% or less to obtain a liquid crystal polyester solution. When the oxygen concentration is high, the strength of the obtained film is lowered. The oxygen concentration is preferably 2% or less. The gas other than oxygen is preferably nitrogen.

  The liquid crystalline polyester is dissolved in the solvent at a temperature of 140 ° C. or higher and 200 ° C. or lower. Although it can melt | dissolve in a short time, so that it melt | dissolves at high temperature, when too high, when the solution obtained is cooled to room temperature, there exists a tendency for a solution viscosity to become low and for the film obtained to become brittle. In the present invention, since it is dissolved in an atmosphere having a low oxygen concentration, the liquid crystal polyester can be dissolved in the solvent at a considerably high temperature. Moreover, if it is made to melt | dissolve at low temperature, it will take time to make it melt | dissolve and productivity will be bad. In the present invention, the temperature at which the liquid crystalline polyester is dissolved in the solvent is preferably 150 ° C. or higher and 180 ° C. or lower, and more preferably 155 ° C. or higher and 170 ° C. or lower.

  The liquid crystal polyester solution is preferably filtered through a filter or the like as necessary to remove fine foreign matters contained in the solution composition.

  In addition, the liquid crystalline polyester solution includes an inorganic filler such as silica, aluminum hydroxide, and calcium carbonate, an organic filler such as a cured epoxy resin, a crosslinked benzoguanamine resin, and a crosslinked acrylic polymer, polyamide, Polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenyl ether and modified products thereof, thermoplastic resins such as polyetherimide, thermosetting resins such as phenol resin, epoxy resin, polyimide resin, cyanate resin, Various additives such as a silane coupling agent, an antioxidant, and an ultraviolet absorber may be added alone or in combination.

  Examples of a method for obtaining a liquid crystal polyester film from the liquid crystal polyester solution of the present invention include a method of casting the liquid crystal polyester solution on a surface smooth substrate such as glass or metal and removing the solvent.

  The method for removing the solvent is not particularly limited, but it is preferably performed by evaporation of the solvent. Examples of the method for evaporating the solvent include methods such as heating, decompression, and ventilation.

  The obtained liquid crystal polyester film may be further heat-treated as necessary.

  The liquid crystal polyester film thus obtained has excellent tear strength in the direction perpendicular to the flow direction during molding, and has excellent properties such as low moisture absorption and high frequency properties possessed by the liquid crystal polyester, and has high strength. Therefore, semiconductor packages and multilayer printed circuit boards for motherboards, flexible printed wiring boards, films for tape automated bonding, other 8mm video tape base materials, and commercial digital video, which have been gaining attention in recent years, such as build-up methods. For tape substrate, transparent conductive (ITO) film substrate, polarizing film substrate, cooking food, microwave oven packaging film, electromagnetic shielding film, antibacterial film, gas separation film, etc. It can be preferably used.

EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, it cannot be overemphasized that this invention is not what is limited by an Example.
The tensile strength characteristics were measured by the following method.
The maximum breaking point when a 20 μm-thick dumbbell-shaped test piece prepared using ASTM No. 4 dumbbell was pulled at a span distance of 20 mm using Shimadzu Corporation AUTOGRAPH AG-5000D was defined as the tensile strength.

Example 1
In a reactor equipped with a stirrer, a torque meter, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, 141 g (1.02 mol) of p-hydroxybenzoic acid, 63.3 g of 4,4′-dihydroxybiphenyl (0. 34 mol), 56.5 g (0.34 mol) of isophthalic acid, and 191 g (1.87 mol) of acetic anhydride. After sufficiently replacing the inside of the reactor with nitrogen gas, the temperature was raised to 150 ° C. over 15 minutes under a nitrogen gas stream, and the temperature was maintained and refluxed for 3 hours.
Thereafter, while distilling off distilling by-product acetic acid and unreacted acetic anhydride, the temperature was raised to 320 ° C. over 170 minutes. The time point at which an increase in torque was observed was regarded as completion of the reaction, and the contents were taken out. The obtained solid content was cooled to room temperature, pulverized with a coarse pulverizer, held at 250 ° C. for 3 hours in a nitrogen atmosphere, and the polymerization reaction was advanced in a solid layer to obtain an aromatic liquid crystal polyester powder. In the obtained powder, a schlieren pattern peculiar to the liquid crystal phase was observed at 350 ° C. with a deflection microscope.

  0.4 g of the obtained aromatic liquid crystal polyester powder was compression molded using a flow tester CFT-500 manufactured by Shimadzu Corporation under a 100 kg load at 250 ° C. for 10 minutes, and a disk-shaped test piece having a thickness of 3 mm. Got. Using this test piece, the water absorption rate at 85 ° C./85% RH · 168 hours was measured by a constant temperature and humidity machine ADVANTEC AGX type manufactured by Toyo Seisakusho, and it was confirmed that the water absorption rate was 0.1% or less. . Further, the dielectric loss tangent was measured by using an HP impedance analyzer made by Hewlett-Packard, and it was 0.004 (1 GHz).

  As a result of adding 1.0 g of the aromatic liquid crystal polyester powder obtained by the above process to 9.0 g of p-chlorophenol and dissolving it at 160 ° C. in a nitrogen atmosphere having an oxygen concentration of 1.2%, 3 hours later A completely dissolved and clear solution was obtained. Furthermore, when the solution viscosity was measured using a B-type viscometer manufactured by Tokimec, the solution viscosity was 350 poise (25 ° C.). Table 1 shows the relationship between dissolution temperature, solution viscosity, and tensile strength. This solution was cast on a glass plate, the solvent was evaporated with a hot plate at a set temperature of 100 ° C. for 1 hour, and heat treatment was performed with a hot air dryer at 250 ° C. for 1 hour. As a result, an aroma having a thickness of 25 μm was obtained. A liquid crystal polyester film was obtained. In addition, when the solution was cast on a glass plate, the castability of the solution was excellent and the film forming property was good. Moreover, about the obtained aromatic liquid-crystal polyester film, as a result of measuring an orientation pattern with MOA-5012 simple molecular orientation meter by Oji Scientific Instruments, it confirmed that the ratio of the vertical direction and the horizontal direction was 1, and there was no anisotropy. did.

Comparative Example 1
As a result of adding 1.0 g of the aromatic liquid crystal polyester powder obtained in Example 1 to 9.0 g of p-chlorophenol and dissolving it in an atmosphere having an oxygen concentration of 20.8% at 120 ° C. A clear solution was obtained. When the solution viscosity was measured using a B-type viscometer manufactured by Tokimec, the solution viscosity was 780 poise (25 ° C.). When this solution was cast on a glass plate, the solution viscosity was high and the castability was poor. As a result of evaporating the solvent with a hot plate at a set temperature of 100 ° C. for 1 hour and further performing a heat treatment with a hot air dryer at 250 ° C. for 1 hour, an aromatic liquid crystal polyester film having a thickness of 25 μm was obtained. Thick spots and irregularities were seen on the surface, and the surface condition was poor.

Comparative Example 2
As a result of adding 1.0 g of the aromatic liquid crystal polyester powder obtained in Example 1 to 9.0 g of p-chlorophenol and dissolving it in an atmosphere having an oxygen concentration of 20.8% at 160 ° C. A clear solution was obtained. When the solution viscosity was measured using a B-type viscometer manufactured by Tokimec, the solution viscosity was 65 poise (25 ° C.). This solution was cast on a glass plate, the solvent was evaporated on a hot plate at a set temperature of 100 ° C. for 1 hour, and heat treatment was further performed on a hot air dryer at 250 ° C. for 1 hour. Was brittle and could not be obtained in the form of a film.

芳香族液晶ポリエステル溶解量＝１０重量％

Dissolving amount of aromatic liquid crystal polyester = 10% by weight

Claims (4)

A liquid crystal polyester solution obtained by dissolving 0.5 to 100 parts by weight of a liquid crystal polyester in an atmosphere having an oxygen concentration of 5% or less at a temperature of 140 ° C. or higher and 200 ° C. or lower with respect to 100 parts by weight of the following solvent.
Solvent: A solvent containing a halogen-substituted phenol compound represented by the following general formula (I).

(In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents the number of A and represents an integer of 1 to 5, and when i is 2 or more, a plurality of A's are the same or different from each other. May be good.)   The liquid crystal polyester solution according to claim 1, obtained by dissolving at a temperature of 150 ° C or higher and 180 ° C or lower. A method for producing a liquid crystal polyester solution in which 0.5 to 100 parts by weight of a liquid crystal polyester is dissolved at a temperature of 140 ° C. or more and 200 ° C. or less in an atmosphere having an oxygen concentration of 5% or less with respect to 100 parts by weight of the following solvent.
Solvent: A solvent containing a halogen-substituted phenol compound represented by the following general formula (I).

(In the formula, A represents a halogen atom or a trihalogenated methyl group, i represents the number of A and represents an integer of 1 to 5, and when i is 2 or more, a plurality of A's are the same or different from each other. May be good.) A liquid crystal polyester film obtained from the liquid crystal polyester solution according to claim 1.