Liquid crystalline polyester composition and film

Abstract

To provide a liquid crystalline polyester composition that enables formation of a film with high mechanical strength, and a film comprising the liquid crystalline polyester composition.SOLUTION: This liquid crystalline polyester composition comprises a liquid crystalline polyester, an inorganic filler, and a leveling agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal polyester composition and a film. [Background technology]

[0002] Liquid crystal polyesters have attracted attention as materials for electronic substrates because of their excellent high-frequency characteristics and low moisture absorption. In particular, a solution composition containing a liquid crystal polyester having structural units derived from an aromatic amine derivative and an organic solvent can be cast onto a support and then the solvent removed from the cast product to produce a liquid crystal polyester film with low anisotropy, making the polyester an excellent material for films for electronic components.

[0003] The composition containing the liquid crystal polyester contains an inorganic filler as needed. For example, Patent Document 1 discloses a liquid crystalline polyester film laminate formed by laminating a liquid crystalline polyester film and a metal film, the liquid crystalline polyester film laminate being 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 aromatic diamines, structural units derived from aromatic amines having a phenolic hydroxyl group, and structural units derived from aromatic amino acids, based on the total structural units, and the liquid crystalline polyester film is disclosed to contain 10 to 50 parts by weight of an inorganic filler based on 100 parts by weight of the liquid crystalline polyester (Claim 2 of Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-342980 Summary of the Invention [Problem to be solved by the invention]

[0005] In the liquid crystal polyester film produced from the conventional liquid crystal polyester composition as described in Patent Document 1, there is room for improvement in mechanical strength.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a liquid crystal polyester composition that can be used to form a film having high mechanical strength, and a film containing the liquid crystal polyester composition. [Means for solving the problem]

[0007] In a composition in which an inorganic filler is added to a liquid crystal polyester, the inorganic filler may not disperse well in the composition, which may lead to a decrease in the mechanical strength of the film. On the other hand, as a result of intensive research, the present inventors have found that when a leveling agent is further added to the composition, the inorganic filler is uniformly dispersed in the composition due to the interaction between the liquid crystal polyester, the inorganic filler, and the leveling agent, making it possible to form a film having high mechanical strength, and have thus completed the present invention. In order to solve the above problems, the present invention includes the following aspects.

[0008] [1] A liquid crystal polyester composition containing a liquid crystal polyester, an inorganic filler, and a leveling agent. [2] The liquid crystal polyester contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structural unit represented by the following formula (A3), the content of the structural unit represented by the formula (A1) is 30 mol % or more and 80 mol % or less based on all structural units constituting the liquid crystal polyester, the content of the structural unit represented by the formula (A2) is 10 mol % or more and 35 mol % or less based on all structural units constituting the liquid crystal polyester, The liquid crystal polyester composition according to [1], wherein the content of the structural unit represented by the formula (A3) is 10 mol % or more and 35 mol % or less based on all structural units constituting the liquid crystal polyester. (A1)-O-Ar1-CO- (A2)-CO-Ar2-CO- (A3)-X-Ar3-Y- [In the formula, Ar1 represents a 1,4-phenylene group, a 2,6-naphthalene group, or a 4,4'-biphenylene group, Ar2 represents a 1,4-phenylene group, a 1,3-phenylene group, or a 2,6-naphthalene group, Ar3 represents a 1,4-phenylene group or a 1,3-phenylene group, X represents -NH-, and Y represents -O- or NH-.] [3] The liquid crystal polyester composition according to [1] or [2], wherein the inorganic filler is talc or mica. [4] The liquid crystal polyester composition according to any one of [1] to [3], wherein the inorganic filler has an average particle size D50 of 100 nm or more and 820 nm or less. [5] The liquid crystal polyester composition according to any one of [1] to [4], wherein the content of the inorganic filler is 10 parts by mass or more and 25 parts by mass or less relative to 100 parts by mass of the total of the liquid crystal polyester, the inorganic filler, and the leveling agent. [6] The liquid crystal polyester composition according to any one of [1] to [5], wherein the leveling agent contains a polyether-modified polydimethylsiloxane. [7] The liquid crystal polyester composition according to any one of [1] to [6], wherein the content of the leveling agent is 0.01 parts by mass or more and 1.5 parts by mass or less relative to 100 parts by mass of the total of the liquid crystal polyester and the inorganic filler. [8] The liquid crystal polyester composition according to any one of [1] to [7], further comprising an organic solvent. [9] A film comprising the liquid crystal polyester composition according to any one of [1] to [7]. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a liquid crystal polyester composition that can be formed into a film having high mechanical strength, and a film containing the liquid crystal polyester composition. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Liquid Crystal Polyester Composition) The liquid crystal polyester composition of the present embodiment contains a liquid crystal polyester, an inorganic filler, and a leveling agent.

[0011] <Liquid Crystal Polyester> Liquid crystal polyester is a polyester resin that exhibits liquid crystallinity in a molten state. The liquid crystal polyester is preferably a liquid crystal polyester that is soluble in an aprotic solvent. Here, solubility in an aprotic solvent can be confirmed by carrying out the following test.

[0012] Testing Method The liquid crystalline polyester is stirred in an aprotic solvent at a temperature of 120 to 180°C for 1 to 6 hours, and then cooled to room temperature. It is then filtered using a 5 μm membrane filter and a pressure filter, and the residue on the membrane filter is checked. If no solid matter is visually observed, the polyester is deemed soluble in the aprotic solvent.

[0013] The liquid crystal polyester preferably contains a structural unit represented by the following formula (A1): The liquid crystal polyester more preferably contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structural unit represented by the following formula (A3). (A1)-O-Ar1-CO- (A2)-CO-Ar2-CO- (A3)-X-Ar3-Y- [In the formula, Ar1 represents a 1,4-phenylene group, a 2,6-naphthalene group, or a 4,4'-biphenylene group, Ar2 represents a 1,4-phenylene group, a 1,3-phenylene group, or a 2,6-naphthalene group, Ar3 represents a 1,4-phenylene group or a 1,3-phenylene group, X represents -NH-, and Y represents -O- or NH-.]

[0014] Examples of the structural unit represented by formula (A1) include a structural unit derived from p-hydroxybenzoic acid, a structural unit derived from 2-hydroxy-6-naphthoic acid, and a structural unit derived from 4-hydroxy-4'-biphenylcarboxylic acid. The liquid crystal polyester may contain one type or two or more types of the structural unit represented by the formula (A1).

[0015] Of the above, the structural unit represented by formula (A1) is preferably a structural unit derived from 2-hydroxy-6-naphthoic acid in which Ar1 is a 2,6-naphthalene group.

[0016] The content of the structural unit represented by formula (A1) is preferably 30 mol % or more, more preferably 40 mol % or more, and even more preferably 45 mol % or more, based on all structural units constituting the liquid crystal polyester. The content of the structural unit represented by formula (A1) is preferably 80 mol % or less, more preferably 70 mol % or less, and even more preferably 65 mol % or less, based on all structural units constituting the liquid crystal polyester.

[0017] When the content of the structural unit represented by formula (A1) is equal to or less than the above preferable upper limit, when the liquid crystal polyester composition of the present embodiment contains a solvent, the solubility of the liquid crystal polyester in the solvent is further improved. When the content of the structural unit represented by formula (A1) is at least the above preferable lower limit, the liquid crystal polyester is more likely to exhibit liquid crystallinity.

[0018] For example, the content of the structural unit represented by formula (A1) is preferably 30 mol% or more and 80 mol% or less, more preferably 40 mol% or more and 70 mol% or less, and even more preferably 45 mol% or more and 65 mol% or less, relative to all structural units constituting the liquid crystal polyester.

[0019] Examples of the structural unit represented by formula (A2) include a structural unit derived from terephthalic acid, a structural unit derived from isophthalic acid, and a structural unit derived from 2,6-naphthalenedicarboxylic acid. The liquid crystal polyester may contain one type or two or more types of the structural unit represented by the formula (A2).

[0020] Of the above, the structural unit represented by formula (A2) is preferably a structural unit derived from isophthalic acid in which Ar2 is a 1,3-phenylene group.

[0021] The content of the structural unit represented by formula (A2) is preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 17.5 mol % or more, based on all structural units constituting the liquid crystal polyester. The content of the structural unit represented by formula (A2) is preferably 35 mol % or less, more preferably 30 mol % or less, and even more preferably 27.5 mol % or less, based on all structural units constituting the liquid crystal polyester.

[0022] When the content of the structural unit represented by formula (A2) is equal to or less than the above preferable upper limit, the liquid crystal polyester is more likely to exhibit liquid crystallinity. When the content of the structural unit represented by formula (A2) is equal to or more than the above preferable lower limit, when the liquid crystal polyester composition of the present embodiment contains a solvent, the solubility of the liquid crystal polyester in the solvent is further improved.

[0023] For example, the content of the structural unit represented by formula (A2) is preferably 10 mol% or more and 35 mol% or less, more preferably 15 mol% or more and 30 mol% or less, and even more preferably 17.5 mol% or more and 27.5 mol% or less, relative to all structural units constituting the liquid crystal polyester.

[0024] Examples of the structural unit represented by formula (A3) include a structural unit derived from 3-aminophenol, a structural unit derived from 4-aminophenol, a structural unit derived from 1,4-phenylenediamine, a structural unit derived from 1,3-phenylenediamine, and a structural unit derived from 4-aminobenzoic acid. The liquid crystal polyester may contain one type or two or more types of the structural unit represented by the formula (A3).

[0025] Of the above, the structural unit represented by formula (A3) is preferably a structural unit derived from 4-aminophenol in which Ar3 is a 1,4-phenylene group, X is -NH-, and Y is -O-.

[0026] The content of the structural unit represented by formula (A3) is preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 17.5 mol % or more, based on all structural units constituting the liquid crystal polyester. The content of the structural unit represented by formula (A3) is preferably 35 mol % or less, more preferably 30 mol % or less, and even more preferably 27.5 mol % or less, based on all structural units constituting the liquid crystal polyester.

[0027] When the content of the structural unit represented by formula (A3) is equal to or less than the above preferable upper limit, the liquid crystal polyester is more likely to exhibit liquid crystallinity. When the content of the structural unit represented by formula (A3) is equal to or more than the above preferable lower limit, when the liquid crystal polyester composition of the present embodiment contains a solvent, the solubility of the liquid crystal polyester in the solvent is further improved.

[0028] For example, the content of the structural unit represented by formula (A3) is preferably 10 mol% or more and 35 mol% or less, more preferably 15 mol% or more and 30 mol% or less, and even more preferably 17.5 mol% or more and 27.5 mol% or less, relative to all structural units constituting the liquid crystal polyester.

[0029] The ratio of the content of the structural unit represented by formula (A2) to the content of the structural unit represented by formula (A3), expressed as [content of the structural unit represented by formula (A2)] / [content of the structural unit represented by formula (A3)] (mol / mol), is preferably 0.9 / 1 to 1 / 0.9, more preferably 0.95 / 1 to 1 / 0.95, and even more preferably 0.98 / 1 to 1 / 0.98.

[0030] The flow initiation temperature of the liquid crystal polyester is preferably 250°C or higher, more preferably 250 to 350°C, and even more preferably 280 to 340°C. The higher the flow initiation temperature, the more likely it is that the heat resistance, strength, and rigidity will improve. However, if the temperature is too high, the solubility in the solvent will tend to decrease, and the viscosity of the liquid composition will tend to increase.

[0031] In this specification, the flow initiation temperature of a liquid crystalline polyester is also called the flow temperature or fluidity temperature, and is the temperature at which the liquid crystalline polyester exhibits a viscosity of 4800 Pa s when melted and extruded from a nozzle having an inner diameter of 1 mm and a length of 10 mm using a capillary rheometer while heating at a rate of 4°C / min under a load of 9.8 MPa, and is an index of the molecular weight of the liquid crystalline polyester (see "Liquid Crystal Polymer - Synthesis, Molding, and Applications" edited by Naoyuki Koide, CMC Corporation, June 5, 1987, p. 95).

[0032] In the liquid crystal polyester composition of the present embodiment, the liquid crystal polyester may be used alone or in combination of two or more kinds.

[0033] Examples of a method for producing the liquid crystal polyester in this embodiment include a method in which an aromatic hydroxy acid corresponding to the structural unit represented by formula (A1), an aromatic amine having a phenolic hydroxy group corresponding to the structural unit represented by formula (A3), or a phenolic hydroxy group or an amino group of an aromatic diamine is acylated with an excess amount of a fatty acid anhydride to obtain an acylated product, and the obtained acylated product is melt-polymerized by ester-amide exchange (polycondensation) with an aromatic dicarboxylic acid corresponding to the structural unit represented by formula (A2) (see, for example, JP-A Nos. 2002-220444 and 2002-146003).

[0034] 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 groups and amino groups, and more preferably 1.05 to 1.1 times equivalent. If the amount of fatty acid anhydride added is too small, the acylated product and raw material monomers tend to sublimate during transesterification and transamidation (polycondensation), which can easily clog the reaction system. If the amount is too large, the resulting liquid crystalline polyester tends to become significantly colored.

[0035] The acylation reaction is preferably carried out at 130 to 180°C for 5 minutes to 10 hours, and more preferably at 140 to 160°C for 10 minutes to 3 hours.

[0036] The fatty acid anhydride used in the acylation reaction is not particularly limited, but examples thereof include acetic anhydride, propionic anhydride, butyric anhydride, isobutyric anhydride, valeric anhydride, pivalic anhydride, 2-ethylhexanoic anhydride, monochloroacetic anhydride, dichloroacetic anhydride, trichloroacetic anhydride, monobromoacetic anhydride, dibromoacetic anhydride, tribromoacetic anhydride, monofluoroacetic anhydride, difluoroacetic anhydride, trifluoroacetic anhydride, glutaric anhydride, maleic anhydride, succinic anhydride, and β-bromopropionic anhydride, and two or more of these may be used in combination. In this embodiment, acetic anhydride, propionic anhydride, butyric anhydride, or isobutyric anhydride is preferred, and acetic anhydride is more preferred.

[0037] In transesterification or transamidation (polycondensation), the acyl group of the acylated product is preferably 0.8 to 1.2 times the equivalent of the carboxyl group.

[0038] The transesterification and transamidation (polycondensation) is preferably carried out while increasing the temperature up to 400°C at a rate of 0.1 to 50°C / min, and more preferably up to 350°C at a rate of 0.3 to 5°C / min.

[0039] When the acylated product and the carboxylic acid are subjected to transesterification or transamidation (polycondensation), the by-produced fatty acid and unreacted fatty acid anhydride are preferably distilled out of the system by evaporation or the like.

[0040] The acylation reaction, transesterification, and transamidation (polycondensation) may be carried out in the presence of a catalyst, which may be any of those conventionally known as catalysts for polyester polymerization, such as metal salt catalysts such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, and organic compound catalysts such as N,N-dimethylaminopyridine and N-methylimidazole.

[0041] Among these catalysts, heterocyclic compounds containing two or more nitrogen atoms, such as N,N-dimethylaminopyridine and N-methylimidazole, are preferably used (see JP-A No. 2002-146003).

[0042] The catalyst is usually added when the monomers are added, and it is not necessarily required to remove it after acylation. If the catalyst is not removed, transesterification can be carried out as is.

[0043] Polycondensation by transesterification or transamidation is usually carried out by melt polymerization, but melt polymerization and solid-state polymerization may be used in combination. Solid-state polymerization is preferably carried out by extracting the polymer from the melt polymerization process, pulverizing it into powder or flakes, and then using a known solid-state polymerization method. Specifically, for example, a method may be used in which the polymer is heat-treated in a solid state at 20 to 350°C for 1 to 30 hours in an inert atmosphere such as nitrogen. Solid-state polymerization may be carried out with or without stirring. By providing an appropriate stirring mechanism, the melt polymerization tank and solid-state polymerization tank can be used in the same reaction tank. After solid-state polymerization, the resulting liquid crystalline polyester may be pelletized and molded by a known method. The liquid crystalline polyester can be produced using, for example, a batch apparatus or a continuous apparatus.

[0044] <Inorganic fillers> The average particle size D50 of the inorganic filler is preferably 100 nm or more, more preferably 300 nm or more, and even more preferably 500 nm or more. The average particle size D50 of the inorganic filler is preferably 820 nm or less, more preferably 750 nm or less, and even more preferably 700 nm or less. For example, the average particle size D50 of the inorganic filler is preferably 100 nm or more and 820 nm or less, more preferably 300 nm or more and 750 nm or less, and even more preferably 500 nm or more and 700 nm or less.

[0045] When the average particle diameter D50 of the inorganic filler is within the above preferred range, the mechanical strength is further improved.

[0046] In this specification, the average particle diameter D50 is the particle diameter at which the cumulative volume ratio from the small particle side becomes 50% in a volume-based cumulative particle diameter distribution curve obtained by laser diffraction / scattering particle diameter distribution measurement. The average particle diameter D50 of the inorganic filler can be measured, for example, using a laser diffraction / scattering particle size distribution measuring device (for example, "LA-950V2" manufactured by HORIBA Corporation).

[0047] Specific examples of the inorganic filler include plate-like inorganic fillers and fibrous inorganic fillers. Examples of the plate-like inorganic filler include talc, mica, plate-like alumina, and glass flakes. Examples of fibrous inorganic fillers include alumina whiskers, titanium oxide whiskers, aluminum borate whiskers, potassium titanate whiskers, barium titanate whiskers, basic magnesium sulfate whiskers, zinc oxide whiskers, and silicon carbide whiskers.

[0048] Of the inorganic fillers listed above, plate-like inorganic fillers are preferred, with talc and mica being more preferred.

[0049] In the liquid crystal polyester composition of the present embodiment, the inorganic filler may be used alone or in combination of two or more kinds.

[0050] <Leveling agent> Specific examples of the leveling agent include polyether-modified polydimethylsiloxane, fluorine-modified polymer, and polyester-modified polydimethylsiloxane. Of the above, polyether-modified polydimethylsiloxane is preferred as the leveling agent.

[0051] <Polyether-modified polydimethylsiloxane> The polyether-modified polydimethylsiloxane used has a structure in which a polyalkylene oxide group is introduced at the end of polydimethylsiloxane. The polyether-modified polydimethylsiloxane is preferably a compound represented by the following formula (S1).

[0052] [ka] [In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 each independently represents H, CH3, C2H5, C3H7, OCH3, or OC2H5. x, y, and z each independently represent an integer of 1 to 20. R is a group represented by the following formula (E1).

[0053] [ka] [In the formula, R 8 represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a group containing a cationically polymerizable group, or a group containing an ethylenically unsaturated group. Each b is independently an integer of 1 to 20. * represents a bond.]

[0054] In the formula (S1), R1 , R 2 , R 3 , R 4 , R 5 , R 6 , and R 7 are preferably each independently CH3, C2H5, OCH3, or OC2H5, and more preferably each independently CH3 or OC2H5.

[0055] In the formula (S1), x, y, and z are each preferably independently an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0056] In the formula (E1), R 8 Specific examples of the group containing a cationically polymerizable group in the formula (1) include an epoxy group, an oxetane group, etc. Specific examples of the group containing an ethylenically unsaturated group include a vinyl group, an acryloyloxy group, a methacryloyloxy group, etc. Among them, R 8 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom.

[0057] In the formula (E1), b is preferably an integer of 1 to 10, and more preferably an integer of 1 to 5.

[0058] The polyether-modified polydimethylsiloxane is more preferably a compound represented by the following formula (S2).

[0059] [ka] [In the formula, x', y', z', and b'' each independently represent an integer of 1 to 5, and n' represents an integer of 1 to 3.]

[0060] The polyether-modified polydimethylsiloxane may be a commercially available polyether-modified polydimethylsiloxane, such as BYK-300, BYK-306, BYK-307, BYK-330, BYK-331, BYK-333, BYK-337, BYK-341, BYK-344, and BYK-378 manufactured by BYK-Chemie Japan, Granol 410 manufactured by Kyoeisha Chemical Co., Ltd., and KF-351 manufactured by Shin-Etsu Chemical Co., Ltd.

[0061] In the liquid crystal polyester composition of the present embodiment, the leveling agent may be used alone or in combination of two or more kinds.

[0062] The content of the inorganic filler is preferably 10 parts by mass or more and 25 parts by mass or less, and more preferably 15 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass in total of the liquid crystal polyester, the inorganic filler, and the leveling agent, It is more preferably 15 parts by mass or more and 20 parts by mass or less.

[0063] The content of the leveling agent is preferably 0.01 parts by mass or more and 1.5 parts by mass or less, more preferably 0.1 parts by mass or more and 1.0 parts by mass or less, and even more preferably 0.5 parts by mass or more and 1.0 parts by mass or less, relative to 100 parts by mass of the total of the liquid crystal polyester and the inorganic filler.

[0064] <Optional ingredients> The liquid crystal polyester composition of the present embodiment may contain any optional components other than the liquid crystal polyester, inorganic filler, and leveling agent described above. Optional components include organic solvents, antifoaming agents, antioxidants, ultraviolet absorbers, flame retardants, dispersants, dyes, and pigments.

[0065] <Organic solvents> Examples of the organic solvent include halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, and o-dichlorobenzene; halogenated phenols such as p-chlorophenol, pentachlorophenol, and pentafluorophenol; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; ketones such as acetone and cyclohexanone; esters such as ethyl acetate and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; amines such as triethylamine; nitrogen-containing heterocyclic aromatic compounds such as pyridine; nitriles such as acetonitrile and succinonitrile; amide solvents (organic solvents having an amide bond) such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone, urea compounds such as tetramethylurea; nitro compounds such as nitromethane and nitrobenzene; sulfur compounds such as dimethyl sulfoxide and sulfolane; and phosphorus compounds such as hexamethylphosphoramide and tri-n-butylphosphate.

[0066] Of the above organic solvents, amide solvents are preferred, and N-methylpyrrolidone is more preferred.

[0067] (liquid crystal polyester solution) In this specification, a liquid crystal polyester composition containing an organic solvent is also referred to as a liquid crystal polyester solution. The liquid crystalline polyester solution according to this embodiment may be a solution obtained by further mixing an inorganic filler and a leveling agent with a mixture of a liquid crystalline polyester and an organic solvent.

[0068] The content of the liquid crystalline polyester is preferably 3% by mass or more and 30% by mass or less, more preferably 3% by mass or more and 20% by mass or less, and even more preferably 5% by mass or more and 10% by mass or less, based on the total amount of the liquid crystalline polyester solution.

[0069] The content of the inorganic filler is preferably 5% by mass or more and 40% by mass or less, more preferably 10% by mass or more and 30% by mass or less, and even more preferably 15% by mass or more and 25% by mass or less, based on the total amount of the liquid crystal polyester solution.

[0070] The content of the leveling agent is preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.03% by mass or more and 0.5% by mass or less, and even more preferably 0.05% by mass or more and 0.1% by mass or less, based on the total amount of the liquid crystal polyester solution.

[0071] (film) The film of the present embodiment can be produced by melt molding the liquid crystal polyester composition described above. Examples of the melt molding method include extrusion molding methods such as the T-die method and the inflation method. The film of the present embodiment is formed from the liquid crystal polyester composition described above, and therefore has high mechanical strength. [Example]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0073] [Flow starting temperature of liquid crystal polyester] First, using a flow tester (Shimadzu Corporation's "CFT-500 model"), about 2 g of liquid crystal polyester was filled into a cylinder equipped with a die having a nozzle with an inner diameter of 1 mm and a length of 10 mm. Next, 9.8 MPa (100 kg / cm 2 The liquid crystalline polyester was melted and extruded from the nozzle while being heated at a rate of 4°C / min under a load of 1000 mbar (0.1 MPa), and the temperature at which the viscosity reached 4800 Pa·s (48,000 poise) was measured, which was taken as the flow initiation temperature of the liquid crystalline polyester.

[0074] [Synthesis of liquid crystal polyester] A reactor equipped with a stirrer, torque meter, nitrogen gas inlet tube, thermometer, and reflux condenser was charged with 941 g (5.0 mol) of 2-hydroxy-6-naphthoic acid, 273 g (2.5 mol) of 4-aminophenol, 415.3 g (2.5 mol) of isophthalic acid, and 1123 g (11 mol) of acetic anhydride. After thoroughly purging 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 while refluxing for 3 hours. Next, while distilling off by-product acetic acid and unreacted acetic anhydride, the temperature was raised from 150°C to 290°C over 4 hours and 15 minutes, and the temperature was maintained at 290°C for 30 minutes. The contents were then removed from the reactor and cooled to room temperature. The obtained solid was pulverized in a pulverizer to obtain a powdered prepolymer. The flow initiation temperature of this prepolymer was 181°C. Next, this prepolymer was heated from room temperature to 250°C over 6 hours under a nitrogen atmosphere, and held at 250°C for 10 hours to undergo solid-state polymerization, followed by cooling to obtain a solid liquid crystalline polyester. The obtained solid was pulverized in a pulverizer to obtain a powdered liquid crystalline polyester. The flow initiation temperature of the liquid crystalline polyester was 240°C. This liquid crystalline polyester was heated from room temperature to 255°C over 6 hours under a nitrogen atmosphere, and held at 255°C for 3 hours to undergo solid-state polymerization, followed by cooling to obtain a powdered liquid crystalline polyester. The flow initiation temperature of the liquid crystalline polyester was 325°C.

[0075] [Preparation of mixed solution] 8 g of the liquid crystal polyester obtained above was added to 92 g of N-methylpyrrolidone, and the mixture was stirred at 140° C. for 4 hours under a nitrogen atmosphere to obtain a mixed solution X.

[0076] (Liquid Crystal Polyester Solution of Example 1) Talc A (NanoAce600: manufactured by Nippon Talc Co., Ltd.: D50 670nm) and polyether-modified polydimethylsiloxane (BYK300: manufactured by BYK-Chemie) were added to the mixed solution X, and the mixture was stirred using a stirring defoamer (manufactured by THINKY: AR-500) to produce the liquid crystal polyester solution of Example 1. The amount of the mixed solution X added was 80 parts by mass, the amount of the talc added was 20 parts by mass, and the amount of the polyether-modified polydimethylsiloxane added was 0.15 parts by mass, based on the total amount of the liquid crystal polyester solution.

[0077] (Liquid Crystal Polyester Composition Solution of Comparative Example 1) The liquid crystal polyester composition of Comparative Example 1 is a mixed liquid X.

[0078] (Liquid Crystal Polyester Composition of Comparative Example 2) To the mixed solution X obtained above, only talc A was added, and the mixture was stirred using a stirring defoamer (AR-500 manufactured by THINKY Corporation) to produce a liquid crystal polyester composition solution of Comparative Example 2. The amount of the mixed solution X added was 80 parts by mass, and the amount of the talc A added was 20 parts by mass, based on the total amount of the liquid crystal polyester solution.

[0079] (Liquid Crystal Polyester Composition Solution of Comparative Example 3) To the mixed solution X obtained above, only talc B (NanoAce800: manufactured by Nippon Talc Co., Ltd.: D50 830nm) was added, and the mixture was stirred using a stirring defoamer (manufactured by THINKY Co., Ltd.: AR-500) to produce the liquid crystal polyester composition of Comparative Example 3. The amount of the mixed solution X added was 80 parts by mass, and the amount of the talc B added was 20 parts by mass, based on the total amount of the liquid crystal polyester solution.

[0080] <Film Preparation> An electrolytic copper foil (Mitsui Mining & Smelting Co., Ltd. "3EC-VLP", 18μ) was placed in an automatic coating device Type I (manufactured by Tester Sangyo), and the GAP setting of a micrometer-equipped film applicator (manufactured by SHEEN) was set to 550 microns. The liquid crystal polyester solution of each example was applied to the glossy surface of the copper foil, and each resin film laminate was produced. Next, the film was dried and the copper foil was removed by the following method to prepare a film of each example having a thickness of about 30 μm. Pre-drying conditions: Dry at 60°C for 3 hours, then dry at 70°C for 3 hours. Annealing was performed at 30°C, followed by drying at 300°C for 4 hours and then at 300°C for 2 hours. Copper foil etching (immersion in ferric chloride solution) 30 minutes immersion Dried at 70°C for 10 minutes.

[0081] [Measurement of elastic modulus (GPa), breaking point test force (N), breaking point stress (MPa)] Tensile tests were performed using an Autograph AG-IS manufactured by Shimadzu Corporation under the following test conditions to measure the modulus of elasticity (GPa), test force at break (N), and stress at break (MPa) of each film. The results are shown in Table 1. Test conditions: Temperature and humidity: 23℃ 50%RH Test speed: 5mm / min

[0082] [Table 1]

[0083] As shown in Table 1, it was confirmed that the liquid crystal polyester composition of Example 1 could have improved mechanical strength compared to the liquid crystal polyester compositions of Comparative Examples 1 to 3.

Claims

1. A liquid crystal polyester composition comprising a liquid crystal polyester, an inorganic filler, and a leveling agent.

2. The liquid crystal polyester contains a structural unit represented by the following formula (A1), a structural unit represented by the following formula (A2), and a structural unit represented by the following formula (A3): the content of the structural unit represented by the formula (A1) is 30 mol % or more and 80 mol % or less based on all structural units constituting the liquid crystal polyester, the content of the structural unit represented by the formula (A2) is 10 mol % or more and 35 mol % or less based on all structural units constituting the liquid crystal polyester, 2. The liquid crystal polyester composition according to claim 1, wherein the content of the structural unit represented by formula (A3) is 10 mol % or more and 35 mol % or less based on all structural units constituting the liquid crystal polyester. (A1)-O-Ar1-CO- (A2)-CO-Ar2-CO- (A3)-X-Ar3-Y- [In the formula, Ar1 represents a 1,4-phenylene group, a 2,6-naphthalene group, or a 4,4'-biphenylene group, Ar2 represents a 1,4-phenylene group, a 1,3-phenylene group, or a 2,6-naphthalene group, Ar3 represents a 1,4-phenylene group or a 1,3-phenylene group, X represents -NH-, and Y represents -O- or NH-.]

3. The liquid crystal polyester composition according to claim 1 or 2, wherein the inorganic filler is talc or mica.

4. The liquid crystal polyester composition according to claim 1 or 2, wherein the inorganic filler has an average particle diameter D50 of 100 nm or more and 820 nm or less.

5. 3. The liquid crystal polyester composition according to claim 1, wherein the content of the inorganic filler is 10 parts by mass or more and 25 parts by mass or less relative to 100 parts by mass of the total of the liquid crystal polyester, the inorganic filler, and the leveling agent.

6. The liquid crystal polyester composition according to claim 1 or 2, wherein the leveling agent comprises a polyether-modified polydimethylsiloxane.

7. 3. The liquid crystal polyester composition according to claim 1, wherein the content of the leveling agent is 0.01 parts by mass or more and 1.5 parts by mass or less relative to 100 parts by mass of the liquid crystal polyester and the inorganic filler in total.

8. The liquid crystal polyester composition according to claim 1 or 2, further comprising an organic solvent.

9. A film comprising the liquid crystal polyester composition according to claim 1 or 2.

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