JP4479355B2 - Aromatic liquid crystal polyester film laminate and flexible printed wiring board using the same - Google Patents

Description

  The present invention relates to a liquid crystalline polyester film laminate and a flexible printed wiring board using the same.

Since liquid crystalline polyester exhibits excellent low moisture absorption, heat resistance, and mechanical strength, it is widely used mainly for precision electronic parts such as connectors obtained by injection molding. In recent years, attention has been focused on forming liquid crystalline polyester into a film by extrusion molding such as T-die molding or inflation molding and applying it to insulating films for multilayer printed boards and flexible printed wiring boards.
However, the conventional liquid crystalline polyester film obtained by extrusion molding has a problem that the anisotropy at the time of molding is large and the tear strength in the direction perpendicular to the flow direction at the time of molding is weak.
In order to solve this problem, a liquid crystalline polyester film obtained from a liquid crystalline polyester solution containing a solvent such as p-chlorophenol has been proposed (see Patent Document 1).

JP 2002-114894 A

A liquid crystalline polyester film laminate formed by laminating a liquid crystal polyester film and a metal film will be used as a substrate of a flexible printed wiring board. However, a liquid crystalline polyester film laminate obtained by laminating a liquid crystalline polyester film obtained from the above solution and a metal film often has a larger linear expansion coefficient than that of the metal film. The obtained liquid crystalline polyester film laminate sometimes warps during heating. In addition, the flexible printed wiring board is required to have excellent bending resistance.
An object of the present invention is to provide a liquid crystalline polyester film laminate and a use thereof which are formed by laminating a liquid crystalline polyester film and a metal film, have improved warpage during heating, and have excellent bending resistance.

  That is, the present invention relates to a liquid crystalline polyester film laminate formed by laminating a liquid crystalline polyester film and a metal film, the structural unit derived from an aromatic diamine, the structural unit derived from an aromatic amine having a phenolic hydroxyl group, and an aromatic The liquid crystalline polyester film laminate, which is a film made of a liquid crystalline polyester containing 10 to 35 mol% of at least one structural unit selected from the group consisting of structural units derived from group amino acids, based on the total structural units is provided. Moreover, the flexible printed wiring board formed using this liquid crystalline polyester film laminated body is provided.

  According to the present invention, a liquid crystalline polyester film and a metal film are laminated, the warp during heating is improved, and it is possible to provide a liquid crystalline polyester film laminate excellent in bending resistance and its use. Become.

The liquid crystalline polyester solution used in the present invention exhibits optical anisotropy at the time of melting, and forms an anisotropic melt at a temperature of 450 ° C. or lower. The structural unit derived from an aromatic diamine, a phenolic hydroxyl group It is a liquid crystalline polyester containing 10 to 35 mol% of at least one structural unit selected from the group consisting of a structural unit derived from an aromatic amine and a structural unit derived from an aromatic amino acid.
The liquid crystalline polyester includes structural units represented by the following formulas (1), (2), and (3) as structural units, the structural unit represented by the formula (1) is 30 to 80 mol%, and the formula (2) It is preferable that the structural unit shown by 35-10 mol% and the structural unit shown by Formula (3) is 35-10 mol%.
(1) -O-Ar1-CO-
(2) -CO-Ar2-CO-
(3) -X-Ar3-Y-
Here, Ar1 represents 1,4-phenylene, 2,6-naphthylene, or 4,4′-biphenylene. Ar2 represents 1,4-phenylene, 1,3-phenylene, or 2,6-naphthylene. Ar3 represents 1,4-phenylene or 1,3-phenylene. X represents —NH—, and Y represents —O— or —NH—.

  The structural unit (1) is a structural unit derived from an aromatic hydroxy acid, the structural unit (2) is a structural unit derived from an aromatic dicarboxylic acid, and the structural unit (3) is an aromatic having an aromatic diamine and a phenolic hydroxyl group. The structural unit is derived from an amine, but instead of these, an ester or amide-forming derivative thereof may be used.

Examples of ester-forming derivatives of carboxylic acids include those in which the carboxyl group is a derivative having a high reaction activity such as an acid chloride or an acid anhydride that promotes the reaction to form a polyester. And those that form esters with alcohols, ethylene glycol, or the like that form polyesters by transesterification.
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.
Examples of the amide-forming derivative of an amino group include those in which an amino group forms an amide with a carboxylic acid so that a polyamide is formed by an amide exchange reaction.

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

Examples of the structural unit represented by the formula (1) include structural units derived from p-hydroxybenzoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxy-4′-biphenylcarboxylic acid, and the like. The above structural units may be included in all structural units. Among these structural units, it is preferable to use a liquid crystalline polyester containing a structural unit derived from 2-hydroxy-6-naphthoic acid.
The structural unit (1) is preferably from 30 to 80 mol%, more preferably from 40 to 70 mol%, still more preferably from 45 to 65 mol%, based on all structural units. When there are many structural units (1), the solubility to a solvent tends to fall remarkably, and when too few, there exists a tendency which does not show liquid crystallinity.

Examples of the structural unit represented by the formula (2) include terephthalic acid, isophthalic acid, and structural units derived from 2,6-naphthalenedicarboxylic acid, and two or more kinds of the structural units are present in all the structural units. It may be included. Among these structural units, from the viewpoint of solubility in a solvent, it is preferable to use a liquid crystalline polyester containing a structural unit derived from isophthalic acid.
The structural unit (2) is preferably from 35 to 10 mol%, more preferably from 30 to 15 mol%, further preferably from 27.5 to 17.5 mol%, based on all structural units. preferable. When there are too many structural units (2), there exists a tendency for liquid crystallinity to fall, and when there are few, there exists a tendency for the solubility to a solvent to fall.

Examples of the structural unit represented by the formula (3) include 3-aminophenol, 4-aminophenol, 1,4-phenylenediamine, 1,3-phenylenediamine, and a structural unit derived from 4-aminobenzoic acid. Two or more kinds of the structural units may be contained in all the structural units. Among these structural units, it is preferable to use a liquid crystalline polyester containing a structural unit derived from 4-aminophenol from the viewpoint of reactivity.
The structural unit (3) is preferably 35 to 10 mol%, more preferably 30 to 15 mol%, and more preferably 27.5 to 17.5 mol% with respect to the total structural units. Further preferred. When there are too many structural units (3), there exists a tendency for liquid crystallinity to fall, and when there are few, there exists a tendency for the solubility to a solvent to fall.
The structural unit (3) is preferably used in substantially the same amount as the structural unit (2), but the structural unit (3) should be −10 mol% to +10 mol% with respect to the structural unit (2). Thus, the degree of polymerization of the liquid crystalline polyester can be controlled.

  Although the manufacturing method of liquid crystalline polyester used by this invention is not specifically limited, For example, the aromatic amine which has the phenolic hydroxyl group corresponding to the aromatic hydroxy acid corresponding to structural unit (1), and structural unit (3) , Acylating the phenolic hydroxyl group or amino group of the aromatic diamine with an excess of fatty acid anhydride to obtain an acylated product, and esterifying the resulting acylated product with the aromatic dicarboxylic acid corresponding to the structural unit (2) Examples include a method of melt polymerization by amide exchange (polycondensation). (See JP2002-220444 and JP2002-146003)

  In the acylation reaction, the amount of fatty acid anhydride added is preferably 1.0 to 1.2 times equivalent to the total of the phenolic hydroxyl group and amino group, more preferably 1.05 to 1. 1 equivalent. If the amount of fatty acid anhydride added is too small, acylated products and raw material monomers will sublimate during transesterification and amide exchange (polycondensation), and the reaction system tends to be clogged. There is a tendency that coloring of the conductive polyester becomes remarkable.

  The acylation reaction is preferably performed at 130 to 180 ° C. for 5 minutes to 10 hours, more preferably at 140 to 160 ° C. for 10 minutes 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 preferable, and acetic anhydride is more preferable.

  In the ester exchange / amide exchange (polycondensation), the acyl group of the acylated product is preferably 0.8 to 1.2 times the carboxyl group.

  The transesterification / amide exchange (polycondensation) is preferably carried out while raising the temperature up to 400 ° C. at a rate of 0.1 to 50 ° C./min, and up to 350 ° C. at a rate of 0.3 to 5 ° C./min. More preferably.

  When transesterification and amide exchange (polycondensation) of acylated products and carboxylic acids are performed, the equilibrium is shifted so that by-product fatty acids and unreacted fatty acid anhydrides are distilled out of the system, such as by evaporation. Is preferred.

The acylation reaction, transesterification / amide exchange (polycondensation) 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.
Among these catalysts, heterocyclic compounds containing 2 or more nitrogen atoms such as N, N-dimethylaminopyridine and N-methylimidazole are preferably used (see JP 2002-146003 A).
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 / amide exchange is usually carried out 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.

  The obtained liquid crystalline polyester is preferably used with an inorganic filler added for the purpose of reducing the linear expansion coefficient. It is preferable that the compounding quantity of this inorganic filler is 10-50 weight part with respect to 100 weight of liquid crystalline polyester. If the amount is too small, the effect of reducing the linear expansion coefficient is small. If the amount is too large, the film becomes brittle and the bending resistance is deteriorated. More preferably, the blending amount is 20 to 40 parts by weight of the inorganic filler with respect to 100 parts by weight of the liquid crystalline polyester.

  Examples of the inorganic filler used in the liquid crystalline polyester film laminate of the present invention include silica, alumina, mica, glass, calcium carbonate, titanium oxide, aluminum borate, potassium titanate, barium titanate, strontium titanate, etc. Inorganic fillers used in the above are mentioned, but it is preferable to use a fibrous or plate-like inorganic filler that can lower the linear expansion coefficient of the liquid crystalline polyester film even with a small amount of addition.

Examples of the fibrous inorganic filler include alumina whisker, titanium oxide whisker, aluminum borate whisker, potassium titanate whisker, barium titanate whisker, basic magnesium sulfate whisker, zinc oxide whisker, and silicon carbide whisker. Of these, alumina whiskers or aluminum borate whiskers are particularly preferred.
The shape of the fibrous inorganic filler is preferably an average fiber length of 0.1 to 100 μm, more preferably an average fiber length of 0.1 to 10 μm, and most preferably an average fiber length of 0.2 to 1 μm. The aspect ratio (ratio of average fiber length to average fiber diameter) is preferably 3 or more, and more preferably 10 or more.

Examples of the plate-like inorganic filler include mica (mica), talc, plate-like alumina, and glass flakes.
The plate-like inorganic filler preferably has an average particle size of 0.1 to 100 μm, more preferably an average particle size of 0.1 to 10 μm. The aspect ratio (ratio of average particle diameter to average thickness) is preferably 3 or more, and more preferably 10 or more.

  The above fibrous and plate-like inorganic fillers may be used in combination, and other spherical inorganic fillers such as silica, alumina, glass, calcium carbonate, titanium oxide, barium titanate, and strontium titanate may be further added. It doesn't matter.

  The inorganic filler may be subjected to a surface treatment with a known coupling agent, anti-settling agent or the like.

  Furthermore, thermoplastic resins such as polypropylene, polyamide, polyester, polyphenylene sulfide, polyether ketone, polycarbonate, polyether sulfone, polyphenyl ether and modified products thereof, polyether imide, glycidyl methacrylate, and the like within the scope of the present invention. One or two or more elastomers such as a copolymer of ethylene and ethylene may be added.

  The liquid crystalline polyester film used in the present invention is a film made of the above liquid crystalline polyester. A known method may be applied as a method for producing the film. However, in light of the object of the present invention, a method of removing the solvent after casting the liquid crystalline polyester solution into a film is preferable. That is, the liquid crystalline polyester film used in the present invention is preferably a liquid crystalline polyester film obtained by casting the liquid crystalline polyester solution into a film and then removing the solvent.

  The amount of the solvent used for preparing the liquid crystalline polyester solution is not particularly limited as long as the liquid crystalline polyester can be dissolved, and can be appropriately selected according to the use. It is preferable to use it so that it may become 0.01-100 weight part of liquid crystalline polyester. If the concentration of the liquid crystalline polyester is too low, the solution viscosity tends to be too low to uniformly coat, whereas if it is too high, the viscosity tends to increase. From the viewpoint of workability and economy, the liquid crystalline polyester is used in an amount of preferably 1 to 50 parts by weight, more preferably 2 to 40 parts by weight with respect to 100 parts by weight of the solvent.

The solvent used for the preparation of the liquid crystalline polyester solution is not particularly limited as long as it dissolves the liquid crystalline polyester. For the purpose of the present invention, an aprotic solvent is used as the solvent. It is preferable.
Examples of the aprotic solvent include halogen solvents such as 1-chlorobutane, chlorobenzene, 1,1-dichloroethane, 1,2-dichloroethane, chloroform, 1,1,2,2-tetrachloroethane, diethyl ether, tetrahydrofuran, Ether solvents such as 1,4-dioxane, ketone solvents such as acetone and cyclohexanone, ester solvents such as ethyl acetate, lactone solvents such as γ-butyrolactone, carbonate solvents such as ethylene carbonate and propylene carbonate, triethylamine, Amide solvents such as amine solvents such as pyridine, nitrile solvents such as acetonitrile and succinonitrile, N, N′-dimethylformamide, N, N′-dimethylacetamide, tetramethylurea and N-methylpyrrolidone Examples thereof include a solvent, a nitro solvent such as nitromethane and nitrobenzene, a sulfide solvent such as dimethyl sulfoxide and sulfolane, and a phosphate solvent such as hexamethylphosphoric acid amide and tri-n-butylphosphoric acid.
Among these, a solvent containing no halogen atom is preferably used from the viewpoint of influence on the environment, and a solvent having a dipole moment of 3 to 5 is preferably used from the viewpoint of solubility. Specifically, amide solvents such as N, N′-dimethylformamide, N, N′-dimethylacetamide, tetramethylurea and N-methylpyrrolidone, or lactone solvents such as γ-butyrolactone are more preferably used. N, N′-dimethylformamide, N, N′-dimethylacetamide, or N-methylpyrrolidone is more preferably used.

  A solution of the liquid crystalline polyester obtained by dissolving the liquid crystalline polyester in a solvent is filtered with a filter or the like as necessary to remove fine foreign matters contained in the solution. After the solution thus obtained is cast into a film, the solvent is removed to obtain a liquid crystalline polyester film.

The solution can be cast into a film by various means such as roller coating, dip coating, spray coating, spinner coating, curtain coating, slot coating, and screen printing on the support. The method of extending is mentioned.
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, reduced pressure, and ventilation. Among them, it is preferable to evaporate by heating from the viewpoint of production efficiency and handleability, and it is more preferable to evaporate by heating while ventilating. preferable. The heating conditions at this time preferably include a step of performing preliminary drying at 60 to 200 ° C. for 10 minutes to 2 hours and a step of performing heat treatment at 200 to 400 ° C. for 30 minutes to 5 hours.

  The liquid crystalline polyester film laminate of the present invention is formed by laminating the liquid crystalline polyester film and the metal film thus obtained. As described above, when a metal film is used as the support when the solution is cast on a film, the solvent is cast after the solution is cast on the metal film. The liquid crystalline polyester film laminate of the present invention can be obtained by removing. Further, as described above, when a substrate that does not swell in the solvent of the solution is used as the support when the solution is cast on a support when the solution is cast into a film, the solution is filmed on the substrate. If the solvent is removed after casting to form a liquid crystal polyester film by peeling off the substrate and the liquid crystal polyester film, the liquid crystal polyester film of the present invention can be obtained by using the obtained liquid crystal polyester film. A laminate is obtained.

Specifically, the liquid crystalline polyester film laminate of the present invention can be obtained, for example, by the following method.
[Method 1]
The liquid crystalline polyester solution is applied onto a metal film (a metal foil known as a metal foil can be used) by roller coating, dip coating, spray coating, spinner coating, curtain coating, slot coating, and screen. A method of obtaining a laminate of a liquid crystalline polyester film and a metal film by casting the film flatly and uniformly into a film by various means such as a printing method, and then removing the solvent.
[Method 2]
A liquid crystal polyester film and a metal obtained by casting the liquid crystalline polyester solution in a film form on the flat substrate that does not swell in the solvent by the various means, removing the solvent, and then peeling the solution from the substrate. A method of laminating a film (which can be known as a metal foil) by thermocompression bonding with a press or a heating roll in the vicinity of the flow start temperature of the liquid crystalline polyester.
[Method 3]
After casting the liquid crystalline polyester solution into a film on the flat substrate that does not swell in the solvent by the above-mentioned various means, the solvent is removed, and then the liquid crystal polyester film is peeled off from the substrate by sputtering or plating. A method of laminating a metal film by a method such as vapor deposition.
[Method 4]
A liquid crystal polyester film and a metal film obtained by casting a solution of liquid crystalline polyester in a film form on the surface flat substrate that does not swell in the solvent by the above-mentioned various means, removing the solvent, and then peeling from the substrate ( A method of laminating a known metal foil) using a known adhesive such as a hot melt adhesive.

In the liquid crystalline polyester film laminate of the present invention, the thickness of the liquid crystalline polyester film thus obtained is not particularly limited, but is 0.5 to 200 μm from the viewpoint of film forming properties and mechanical properties. It is preferable that the thickness is 5 to 75 μm from the viewpoint of handleability.
The liquid crystalline polyester film can be subjected to a surface treatment as necessary. Examples of the surface treatment method include corona discharge treatment, flame treatment, solvent treatment, UV treatment, and plasma treatment.

  In the liquid crystalline polyester film laminate of the present invention, examples of the metal used as the metal film include gold, silver, copper, aluminum, nickel, etc. Among them, copper is preferably used. The thickness of the metal film is preferably in the range of 1 to 75 μm, and more preferably in the range of 5 to 50 μm.

  The liquid crystalline polyester film laminate thus obtained can be suitably used particularly for film applications for electronic parts such as flexible printed wiring boards because the laminate is less warped and has excellent bending resistance. it can.

  EXAMPLES Hereinafter, although this invention is demonstrated using an Example, it cannot be overemphasized that this invention is not what is limited by an Example.

Example 1
In a reactor equipped with a stirrer, torque meter, nitrogen gas introduction tube, thermometer and reflux condenser, 941 g (5.0 mol) of 2-hydroxy-6-naphthoic acid and 273 g (2.5 mol) of 4-aminophenol were added. ), 415.3 g (2.5 mol) of isophthalic acid and 1123 g (11 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 300 ° C. over 150 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 taken-out contents were cooled to room temperature, pulverized by a coarse pulverizer, then raised to 200 ° C. in a nitrogen atmosphere in 1 hour, and then held at 250 ° C. for 3 hours to proceed polymerization in a solid phase. The obtained solid content is cooled to room temperature, pulverized with a coarse pulverizer, then raised to 180 ° C. in a nitrogen atmosphere in 1 hour, then held at 250 ° C. for 3 hours to proceed polymerization in a solid phase, and aromatic liquid crystalline polyester powder Got. The obtained resin exhibited a schlieren pattern peculiar to a liquid crystal phase at 370 ° C. by observation with a polarizing microscope.

8 g of the aromatic liquid crystal polyester powder obtained as described above was added to 92 g of N-methylpyrrolidone and heated to 160 ° C. to obtain an aromatic liquid crystal polyester solution. The obtained solution was cast into a film on a copper foil (CF-T9FZ-SV (thickness 18 μm) made by Fukuda Metals) by a bar coating method, and then heat-treated at 100 ° C. for 1 hour and 300 ° C. for 1 hour. As a result, a film with a copper foil having a resin layer thickness of 20 μm was obtained. The obtained film with copper foil hardly warped.
Next, the copper foil was removed from the obtained film with copper foil to obtain a single-layer aromatic liquid crystal polyester film, and the linear expansion coefficient and bending resistance of the aromatic liquid crystal polyester film were evaluated. As a result of evaluating the linear expansion coefficient using TMA8140C manufactured by Rigaku, the linear expansion coefficient was 40 ppm / ° C. (temperature: 50 ° C. to 100 ° C.). Further, bending resistance was evaluated using an MIT bending tester (corner R = 0.38 mm) manufactured by Toyo Seiki. As a result, bending resistance of 50000 times or more was shown.

Example 2
8 g of the aromatic liquid crystal polyester powder obtained in Example 1 was added to 92 g of N-methylpyrrolidone, and further, an aluminum borate whisker M20C manufactured by Shikoku Kasei Kogyo (average fiber length 0.5 μm, average fiber diameter 0.1 μm) Was added and heated to 160 ° C. to obtain an aromatic liquid crystal polyester solution. The obtained solution was bar-coated on a copper foil (CF-T9FZ-SV (thickness: 18 μm) made by Fukuda Metals) and then heat-treated at 100 ° C. for 1 hour and at 300 ° C. for 1 hour. As a result, a film with a copper foil having a resin layer thickness of 20 μm was obtained. The obtained film with copper foil hardly warped.
Next, the copper foil was removed from the film with copper foil to obtain a single layer aromatic liquid crystal polyester film. The linear expansion coefficient and bending resistance of this aromatic liquid crystal polyester film were evaluated. As a result of evaluating the linear expansion coefficient using TMA8140C manufactured by Rigaku, the linear expansion coefficient was 22 ppm / ° C. (temperature: 50 ° C. to 100 ° C.). Further, bending resistance was evaluated using a Toyo Seiki MIT bending tester (corner R = 0.38 mm), and as a result, bending resistance of 50000 times or more was shown.

Comparative 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.
8 g of the aromatic liquid crystal polyester powder obtained by the above process was added to 92 g of p-chlorophenol and heated to 120 ° C. to obtain an aromatic liquid crystal polyester solution. The obtained solution was bar-coated on a copper foil (CF-T9FZ-SV (thickness: 18 μm) made by Fukuda Metals) and then heat-treated at 100 ° C. for 1 hour and at 300 ° C. for 1 hour. As a result, a film with a copper foil having a resin layer thickness of 20 microns was obtained. A large warp was observed in the obtained film with copper foil.
Next, the copper foil was removed from the film with copper foil to obtain a single layer aromatic liquid crystal polyester film. The linear expansion coefficient and bending resistance of this aromatic liquid crystal polyester film were evaluated. As a result of evaluating the linear expansion coefficient using TMA8140C manufactured by Rigaku, the linear expansion coefficient was 70 ppm / ° C. (temperature: 50 ° C. to 100 ° C.). Further, bending resistance was evaluated using a Toyo Seiki MIT bending tester (corner R = 0.38 mm). As a result, bending resistance of 50000 times or more was shown.

Claims (2)

A method for producing a liquid crystalline polyester film laminate comprising a liquid crystalline polyester film and a metal film, wherein the structural unit is derived from an aromatic diamine, the structural unit is derived from an aromatic amine having a phenolic hydroxyl group, and an aromatic amino acid. By casting a liquid crystalline polyester solution containing 10 to 35 mol% of at least one structural unit selected from the group consisting of derived structural units in the form of a film, and then removing the solvent. The manufacturing method of the said liquid crystalline polyester film laminated body which obtains the said liquid crystalline polyester film. The manufacturing method of the liquid crystalline polyester film laminated body of Claim 1 with which the inorganic filler is mix | blended in the said solution in the range of 10-50 weight part with respect to 100 weight part of liquid crystalline polyester.