Liquid crystal polymer composition

Abstract

To provide a liquid crystal polymer composition which has improved flexibility and dielectric constant while maintaining mechanical strength.SOLUTION: A liquid crystal polymer composition contains 100 pts.mass of a liquid crystal polymer, 0.1-30 pts.mass of a cyclic olefinic resin, and 0.1-10 pts.mass of a functional group-containing copolymer, and in a bending test according to ASTM D 790, has maximum strain measured using a strip-shaped test piece of 65 mm×12.7 mm×2.0 mm of 4.5% or more, and a dielectric constant measured at 10 GHz using a test piece of 85 mm×1.7 mm×1.7 mm by a cavity resonator perturbation method according to JIS C 2565 of 3.60 or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a liquid crystal polymer composition having improved flexibility and dielectric constant while maintaining mechanical strength. [Background technology]

[0002] Thermotropic liquid crystal polymers (hereinafter referred to as liquid crystal polymers or LCPs) are used in parts in a wide variety of fields due to their excellent mechanical properties, moldability, chemical resistance, gas barrier properties, moisture resistance, electrical properties, etc. In particular, their use in electronic parts is expanding due to their excellent heat resistance, thin-wall moldability, and insulation properties.

[0003] In recent years, with the development of an advanced information society, the amount of information transmitted and the transmission speed of information and communication devices such as personal computers and mobile phones have increased explosively in the information and communication field. In particular, there is an increasing need for high-performance high-frequency electronic components that can be used in the microwave and millimeter wave high-frequency ranges.

[0004] However, when liquid crystal polymers with high dielectric constants are used as substrates for electrical connectors or flexible printed circuit (FPC) substrates, problems arise such as attenuation of high-frequency signals and a decrease in signal propagation speed. Therefore, liquid crystal polymers used in these electronic components are required to have a low dielectric constant.

[0005] Furthermore, liquid crystal polymers have the drawback of being less flexible due to their rigid molecular structure, and for use as FPC substrates, flexibility is also required in addition to electrical properties such as a low dielectric constant.

[0006] It is generally known that a liquid crystalline polyester resin composition (Patent Document 1) in which glass fibers and glass balloons are blended with a liquid crystalline polymer has a low dielectric constant. In addition, in order to reduce the dielectric constant of a liquid crystalline polymer, a liquid crystalline polyester composition in which a fibrous filler with an aspect ratio of 4 or more and inorganic hollow spheres with a specific particle size are blended has been proposed (Patent Document 2). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-323705 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-143270 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the liquid crystal polyester composition has problems such as the glass beads or inorganic hollow spheres being broken or not being uniformly dispersed in the liquid crystal polymer, which results in a deterioration in the physical properties of the composition or unevenness in the physical properties, and flexibility has not been studied.

[0009] An object of the present invention is to provide a liquid crystal polymer composition which has improved flexibility and dielectric constant while maintaining mechanical strength. [Means for solving the problem]

[0010] In view of the above problems, the present inventors have conducted extensive research and have found that by blending a predetermined amount of a cyclic olefin resin and a functional group-containing copolymer with a liquid crystal polymer, a liquid crystal polymer composition can be obtained that maintains mechanical strength while improving flexibility and dielectric constant, and have thus completed the present invention.

[0011] That is, the present invention includes the following preferred embodiments. [1] A liquid crystal polymer composition comprising 100 parts by mass of a liquid crystal polymer, 0.1 to 30 parts by mass of a cyclic olefin resin, and 0.1 to 10 parts by mass of a functional group-containing copolymer, wherein in a bending test in accordance with ASTM D790, a maximum strain measured using a 65 mm x 12.7 mm x 2.0 mm rectangular test piece is 4.5% or more, and wherein a dielectric constant measured at 10 GHz using an 85 mm x 1.7 mm x 1.7 mm test piece by a cavity resonator perturbation method in accordance with JIS C2565 is 3.60 or less. [2] The liquid crystal polymer is represented by the formulas (I) to (III) [ka] [In the formula, Ar1 and Ar2 each represent one or more divalent aromatic groups, and p, q, and r each represent the composition ratio (mol %) of each repeating unit in the liquid crystal polyester (A), and satisfy the following condition: 35≦p≦90, 5 ≤ q ≤ 30, and 5≦r≦30] A liquid crystal polyester (A) containing a repeating unit represented by the formula: Formula (IV) and Formula (V) [ka] [In the formula, s and t are the composition ratios (mol %) of each repeating unit in the liquid crystal polyester (B), and satisfy the following conditions: 80 / 20≦s / t≦60 / 40 Liquid crystal polyester (B) containing a repeating unit represented by Contains The liquid crystal polymer composition according to [1], wherein the mass ratio of (A) to (B) [(A) / (B)] is 90 / 10 to 45 / 55. [3] The liquid crystal polymer composition according to [1] or [2], wherein the functional group-containing copolymer is a maleic anhydride grafted polyolefin copolymer and / or an epoxy group-containing polyolefin copolymer. [4] A molded article made from the liquid crystal polymer composition according to any one of [1] to [3]. [5] The molded article according to [4], wherein the molded article is selected from the group consisting of a film, a sheet, and an FPC substrate. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a liquid crystal polymer composition that has improved flexibility and dielectric constant while maintaining mechanical strength. DETAILED DESCRIPTION OF THE INVENTION

[0013] The liquid crystal polymer used in the liquid crystal polymer composition of the present invention is a polyester or polyesteramide that forms an anisotropic molten phase, which is called a thermotropic liquid crystal polymer by those skilled in the art, and is not particularly limited as long as it is called a thermotropic liquid crystal polyester or a thermotropic liquid crystal polyesteramide in the technical field.

[0014] The anisotropic melt phase can be confirmed by conventional polarized light examination using crossed polarizers. More specifically, the anisotropic melt phase can be confirmed by observing a sample placed on a Leitz hot stage under a nitrogen atmosphere at 40x magnification using a Leitz polarizing microscope. The liquid crystal polymer of the present invention is optically anisotropic, i.e., it transmits light when examined between crossed polarizers. If the sample is optically anisotropic, polarized light will be transmitted even when the sample is stationary.

[0015] Examples of polymerizable monomers constituting the liquid crystal polymer of the present invention include aromatic hydroxycarboxylic acids, aromatic dicarboxylic acids, aromatic diols, aromatic aminocarboxylic acids, aromatic hydroxyamines, aromatic diamines, aliphatic diols, and aliphatic dicarboxylic acids. The polymerizable monomers constituting the liquid crystal polymer may be one of these compounds or a combination of two or more compounds, but it is desirable to include at least one polymerizable monomer having a hydroxy group and a carboxyl group.

[0016] The polymerizable monomer constituting the liquid crystal polymer may be an oligomer formed by bonding one or more of the above compounds, that is, an oligomer formed from one or more of the above compounds.

[0017] Specific examples of aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid, and alkyl-, alkoxy-, or halogen-substituted derivatives thereof, as well as ester-forming derivatives thereof such as acylation products, ester derivatives, and acid halides. Among these, one or more compounds selected from the group consisting of 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferred from the viewpoint of ease of adjusting the heat resistance, mechanical strength, and melting point of the resulting liquid crystal polymer.

[0018] Specific examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-dicarboxybiphenyl, 3,4'-dicarboxybiphenyl, and 4,4''-dicarboxyterphenyl, as well as alkyl-, alkoxy-, or halogen-substituted derivatives thereof, and ester-forming derivatives thereof, such as ester derivatives and acid halides. Among these, from the viewpoint of effectively enhancing the heat resistance of the resulting liquid crystal polymer, one or more compounds selected from the group consisting of terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid are preferred, and terephthalic acid and 2,6-naphthalenedicarboxylic acid are more preferred.

[0019] Specific examples of aromatic diols include hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, and 2,2'-dihydroxybinaphthyl, as well as ester-forming derivatives thereof such as alkyl, alkoxy, or halogen-substituted derivatives and acylated derivatives thereof. Among these, from the viewpoint of excellent reactivity during polymerization, one or more compounds selected from the group consisting of hydroquinone, resorcinol, 4,4'-dihydroxybiphenyl, and 2,6-dihydroxynaphthalene are preferred, and one or more compounds selected from the group consisting of hydroquinone, 4,4'-dihydroxybiphenyl, and 2,6-dihydroxynaphthalene are more preferred.

[0020] Specific examples of aromatic aminocarboxylic acids include 4-aminobenzoic acid, 3-aminobenzoic acid, 6-amino-2-naphthoic acid, alkyl-, alkoxy-, or halogen-substituted derivatives thereof, and ester-forming derivatives thereof such as acylated products, ester derivatives, and acid halides.

[0021] Specific examples of aromatic hydroxyamines include 4-aminophenol, N-methyl-4-aminophenol, 3-aminophenol, 3-methyl-4-aminophenol, 4-amino-1-naphthol, 4-amino-4'-hydroxybiphenyl, 4-amino-4'-hydroxybiphenyl ether, 4-amino-4'-hydroxybiphenylmethane, 4-amino-4'-hydroxybiphenyl sulfide, and 2,2'-diaminobinaphthyl, as well as ester-forming derivatives thereof such as alkyl, alkoxy, or halogen-substituted derivatives thereof, and acylated derivatives thereof. Among these, 4-aminophenol is preferred from the viewpoint of easily achieving a balance between the heat resistance and mechanical strength of the resulting liquid crystal polymer.

[0022] Specific examples of aromatic diamines include amide-forming derivatives such as 1,4-phenylenediamine, 1,3-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, alkyl-, alkoxy- or halogen-substituted derivatives thereof, and acylated derivatives thereof.

[0023] Specific examples of the aliphatic diol include ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and acylated derivatives thereof. Also, a polymer containing an aliphatic diol, such as polyethylene terephthalate or polybutylene terephthalate, may be reacted with the aromatic oxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, and their acylated derivatives, ester derivatives, acid halides, etc.

[0024] Specific examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, fumaric acid, maleic acid, 1,4-cyclohexanedicarboxylic acid, and hexahydroterephthalic acid. Among these, oxalic acid, succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, and 1,4-cyclohexanedicarboxylic acid are preferred from the viewpoint of excellent reactivity during polymerization.

[0025] In the present invention, the liquid crystal polymer may contain, as a polymerizable monomer, dihydroxyterephthalic acid, 4-hydroxyisophthalic acid, 5-hydroxyisophthalic acid, trimellitic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid, or alkyl, alkoxy, or halogen-substituted derivatives thereof, as well as ester-forming derivatives thereof such as acylation products, ester derivatives, and acid halides, within the scope of the present invention. The amount of these polymerizable monomers used is preferably 10 mol % or less based on the total amount of other polymerizable monomers.

[0026] In the present invention, the liquid crystal polymer may contain a thioester bond, provided that the object of the present invention is not impaired. Polymerizable monomers that provide such a bond include mercapto aromatic carboxylic acids, aromatic dithiols, and hydroxy aromatic thiols. The content of these polymerizable monomers is preferably 10 mol% or less based on the total amount of other polymerizable monomers.

[0027] Polymers that combine these repeating units can form an anisotropic melt phase or not, depending on the monomer composition, composition ratio, and sequence distribution of each repeating unit in the polymer, but the liquid crystal polymer used in the present invention is limited to those that form an anisotropic melt phase.The monomer composition, composition ratio, and sequence distribution of each repeating unit in the polymer can be appropriately selected and adjusted by those skilled in the art so as to obtain a liquid crystal polymer that forms an anisotropic melt phase.

[0028] In one embodiment of the present invention, the liquid crystal polymer is a polymer represented by any one of formulas (I) to (III) [ka] [In the formula, Ar1 and Ar2 each represent one or more divalent aromatic groups, and p, q, and r each represent the composition ratio (mol %) of each repeating unit in the liquid crystal polyester (A), and satisfy the following condition: 35≦p≦90, 5 ≤ q ≤ 30, and 5≦r≦30] A liquid crystal polyester (A) containing a repeating unit represented by the formula: Formula (IV) and Formula (V) [ka] [In the formula, s and t are the composition ratios (mol %) of each repeating unit in the liquid crystal polyester (B), and satisfy the following conditions: 80 / 20≦s / t≦60 / 40 Liquid crystal polyester (B) containing a repeating unit represented by Contains A liquid crystalline polyester having a mass ratio of the liquid crystalline polyester (A) to the liquid crystalline polyester (B) [(A) / (B)] of 90 / 10 to 45 / 55 is preferably used. In this case, the mass ratio of the liquid crystalline polyester (A) to the liquid crystalline polyester (B) [(A) / (B)] is more preferably 85 / 15 to 50 / 50, and further preferably 80 / 20 to 60 / 40.

[0029] The liquid crystal polyester (A) will be described below. The composition ratio p in formula (I) is 35 to 90 mol %, preferably 40 to 85 mol %, more preferably 45 to 80 mol %, and even more preferably 50 to 65 mol %.

[0030] The composition ratio q of formula (II) and the composition ratio r of formula (III) are each 5 to 30 mol %, preferably 7.5 to 29 mol %, more preferably 10 to 27.5 mol %, and even more preferably 17.5 to 25 mol %. q and r are preferably equimolar amounts.

[0031] In the above repeating unit, for example, when Ar1 (or Ar2) represents two or more divalent aromatic groups, it means that the liquid crystal polyester contains two or more repeating units represented by formula (II) (or formula (III)) according to the type of divalent aromatic group. In this case, the composition ratio q according to formula (II) (or the composition ratio r according to formula (III)) represents the total composition ratio of the two or more repeating units.

[0032] Specific examples of monomers that provide the repeating unit represented by formula (I) include 6-hydroxy-2-naphthoic acid and its ester-forming derivatives such as acylates, ester derivatives and acid halides.

[0033] Specific examples of monomers that provide the repeating unit represented by formula (II) include aromatic diols such as hydroquinone, resorcinol, 2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 3,4'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl ether, alkyl-, alkoxy- or halogen-substituted products thereof, and ester-forming derivatives such as acylated products thereof.

[0034] Specific examples of monomers that provide the repeating unit represented by formula (III) include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, and 4,4'-dicarboxybiphenyl, as well as alkyl-, alkoxy-, or halogen-substituted derivatives thereof, and ester-forming derivatives thereof such as ester derivatives and acid halides.

[0035] Among these, the liquid crystal polyester (A) preferably used is one in which Ar1 and Ar2 in the repeating units represented by formula (II) and formula (III) each independently contain one or more aromatic groups selected from the group consisting of aromatic groups represented by formulas (1) to (4). [ka]

[0036] Among these, the aromatic groups represented by formula (1) and formula (3) are more preferred as the repeating unit represented by formula (II) because they facilitate adjustment of the reactivity during polymerization and the mechanical properties, heat resistance, crystalline melting temperature, and molding processability of the resulting liquid crystal polyester (A) to appropriate levels. Monomers that provide these repeating units include 4,4'-dihydroxybiphenyl and hydroquinone, as well as their ester-forming derivatives.

[0037] The repeating unit represented by formula (III) is preferably an aromatic group represented by formula (1) because it allows the mechanical properties, heat resistance, crystalline melting temperature, and moldability of the resulting liquid crystal polyester (A) to be easily adjusted to appropriate levels. Examples of monomers that provide these repeating units include terephthalic acid and its ester-forming derivatives.

[0038] Furthermore, as the liquid crystal polyester (A), it is particularly preferred to use one in which the repeating unit represented by formula (II) contains at least two repeating units represented by formula (1) and formula (3), and the repeating unit represented by formula (3) accounts for preferably 80 to 99.9 mol %, more preferably 85 to 99 mol %, and even more preferably 90 to 98 mol % of 100 mol % of the repeating units represented by formula (II).

[0039] In the liquid crystal polyester (A) of the present invention, the total composition ratio of the repeating units [p+q+r] is preferably 100 mol %, but other repeating units may be further contained within a range that does not impair the object of the present invention.

[0040] Examples of monomers that provide other repeating units include other aromatic hydroxycarboxylic acids, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, aromatic hydroxydicarboxylic acids, aliphatic diols, aliphatic dicarboxylic acids, aromatic mercaptocarboxylic acids, aromatic dithiols, aromatic mercaptophenols, and combinations thereof.

[0041] Specific examples of other aromatic hydroxycarboxylic acids include 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid, and alkyl-, alkoxy-, or halogen-substituted derivatives thereof, as well as ester-forming derivatives thereof such as acylated products, ester derivatives, and acid halides.

[0042] The total composition ratio of the repeating units provided by these other monomer components is preferably 10 mol % or less based on the total repeating units.

[0043] The crystalline melting temperature of the liquid crystal polyester (A) used in the present invention is not particularly limited, but is preferably 310 to 360°C.

[0044] In this specification and claims, the "crystalline melting temperature" is determined from the crystalline melting peak temperature measured using a differential scanning calorimeter (hereinafter abbreviated as DSC) at a heating rate of 20°C / min. More specifically, a sample of liquid crystalline polyester is measured at a temperature rise rate of 20°C / min from room temperature to observe the endothermic peak temperature (Tm1), then held at a temperature 20 to 50°C higher than Tm1 for 10 minutes, then cooled to room temperature at a temperature drop rate of 20°C / min, and then measured again at a temperature rise rate of 20°C / min to observe the endothermic peak. The temperature at the peak top is taken as the crystalline melting temperature of the liquid crystalline polyester. For example, a Seiko Instruments Inc. Exstar 6000 or the like can be used as a measuring instrument.

[0045] The liquid crystal polyester (A) used in the present invention is subjected to a shear rate of 1000 s using a capillary rheometer (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.) with a capillary of 0.7 mmφ×10 mm. -1 The melt viscosity measured under the above conditions at a temperature 30° C. above the crystal melting temperature is preferably 1 to 1000 Pa·s, and more preferably 5 to 300 Pa·s.

[0046] Next, the liquid crystal polyester (B) will be described. In the liquid crystal polyester (B), the molar ratio [s / t] of the repeating unit represented by formula (IV) to the repeating unit represented by formula (V) is 80 / 20 to 60 / 40, and preferably 75 / 25 to 70 / 30.

[0047] Specific examples of the monomer that provides the repeating unit represented by formula (IV) in the liquid crystal polyester (B) include 4-hydroxybenzoic acid and its ester-forming derivatives such as acylates, ester derivatives and acid halides.

[0048] Specific examples of the monomer that provides the repeating unit represented by formula (V) in the liquid crystal polyester (B) include 6-hydroxy-2-naphthoic acid and its ester-forming derivatives such as acylates, ester derivatives, and acid halides.

[0049] In the liquid crystal polyester (B), the total composition ratio of the repeating units [s+t] is preferably 100 mol %, but other repeating units may be further contained within a range that does not impair the object of the present invention.

[0050] Examples of monomers that provide other repeating units constituting the liquid crystal polyester (B) include other aromatic hydroxycarboxylic acids, aromatic diols, aromatic dicarboxylic acids or aromatic hydroxydicarboxylic acids, aromatic hydroxyamines, aromatic diamines, aromatic aminocarboxylic acids, aromatic mercaptocarboxylic acids, aromatic dithiols, aromatic mercaptophenols, and combinations thereof.

[0051] Specific examples of other aromatic hydroxycarboxylic acids include 3-hydroxybenzoic acid, 2-hydroxybenzoic acid, 5-hydroxy-2-naphthoic acid, 7-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, 4'-hydroxyphenyl-4-benzoic acid, 3'-hydroxyphenyl-4-benzoic acid, 4'-hydroxyphenyl-3-benzoic acid, and alkyl-, alkoxy-, or halogen-substituted derivatives thereof, as well as ester-forming derivatives thereof such as acylation products, ester derivatives, and acid halides.

[0052] Specific examples of aromatic diols which are monomers that provide other repeating units are the same as those described as monomers that provide the repeating unit of formula (II).

[0053] Specific examples of aromatic dicarboxylic acids which are monomers that provide other repeating units are the same as those described as monomers that provide the repeating unit of formula (III).

[0054] The total composition ratio of the repeating units provided by these other monomer components is preferably 10 mol % or less based on the total repeating units.

[0055] The crystalline melting temperature of the liquid crystal polyester (B) used in the present invention is not particularly limited, but is preferably from 250 to 300°C, for example.

[0056] The liquid crystal polyester (B) used in the present invention is subjected to a shear rate of 1000 s using a capillary rheometer with a capillary of 0.7 mmφ×10 mm. -1 The melt viscosity measured under the above conditions at a temperature of 40° C. above the crystal melting temperature is preferably 1 to 1000 Pa·s, and more preferably 5 to 300 Pa·s.

[0057] The method for producing the liquid crystal polymer will be described below.

[0058] There is no particular limitation on the method for producing the liquid crystal polymer used in the present invention, and known polycondensation methods for forming ester bonds or the like from the combination of the above-mentioned monomers, such as melt acidolysis and slurry polymerization, can be used.

[0059] The melt acidolysis method is a suitable method for producing the liquid crystalline polymers used in the present invention, in which the monomers are first heated to form a melt of reactants, and the reaction is continued to obtain a molten polyester. A vacuum may be applied to facilitate removal of volatile by-products (e.g., acetic acid, water, etc.) produced in the final stage of condensation.

[0060] Slurry polymerization is a process in which the reaction is carried out in the presence of a heat exchange fluid, and the solid product is obtained in a state suspended in the heat exchange medium.

[0061] In both the melt acidolysis method and the slurry polymerization method, the polymerizable monomer components used in producing the liquid crystal polymer can be subjected to the reaction at room temperature in a modified form in which the hydroxyl group is acylated, i.e., as a lower acylated product. The lower acyl group preferably has 2 to 5 carbon atoms, more preferably 2 or 3 carbon atoms. Particularly preferred is a method in which an acetylated product of the monomer component is used in the reaction.

[0062] The lower acylated monomer may be one which has been previously synthesized by separate acylation, or may be produced in the reaction system by adding an acylating agent such as acetic anhydride to the monomer during the production of the liquid crystal polyester.

[0063] In either the molten acidolysis method or the slurry polymerization method, a catalyst may be used during the reaction, if necessary.

[0064] Specific examples of catalysts include organic tin compounds (dialkyltin oxides such as dibutyltin oxide, diaryltin oxides, etc.), organic titanium compounds (titanium dioxide, antimony trioxide, alkoxytitanium silicates, titanium alkoxides, etc.), alkali and alkaline earth metal salts of carboxylic acids (potassium acetate, sodium acetate, etc.), Lewis acids (BF3, etc.), gaseous acid catalysts such as hydrogen halides (HCl, etc.), and the like.

[0065] The amount of the catalyst used is preferably 10 to 1000 ppm, more preferably 20 to 200 ppm, based on the mass of the monomer.

[0066] The liquid crystal polymer obtained by such a polycondensation reaction is extracted in a molten state from the polymerization reaction vessel, and then processed into pellets, flakes, or powder, and is subjected to molding or melt-kneading.

[0067] The liquid crystal polymer in pellet, flake, or powder form may be heat-treated in a substantially solid state under reduced pressure, vacuum, or an atmosphere of an inert gas such as nitrogen or helium, in order to increase the molecular weight and improve the heat resistance.

[0068] The temperature for the heat treatment carried out in the solid phase is not particularly limited as long as the liquid crystal polymer does not melt, but it is usually carried out at 260 to 350°C, preferably 280 to 320°C.

[0069] The liquid crystal polymer composition of the present invention contains a cyclic olefin resin in addition to the liquid crystal polymer.

[0070] The cyclic olefin resin used in the liquid crystal polymer composition of the present invention is a resin different from a functional group-containing copolymer, and includes a polymer of a cyclic olefin such as norbornene or a polycyclic norbornene monomer, or a copolymer thereof. The cyclic olefin resin may contain a ring-open structure, or may be a hydrogenated cyclic olefin resin containing a ring-open structure. The cyclic olefin resin may also contain structural units derived from a chain olefin and / or a vinyl aromatic compound, to the extent that the transparency is not significantly impaired and the moisture absorption is not significantly increased. The cyclic olefin resin may also have a polar group introduced into its molecule.

[0071] Examples of the chain olefin include ethylene and propylene, and examples of the vinyl aromatic compound include styrene, α-methylstyrene, and alkyl-substituted styrene.

[0072] When the cyclic olefin resin is a copolymer of a cyclic olefin and a chain olefin or a vinyl aromatic compound, the content of structural units derived from the cyclic olefin is usually 50 mol % or less, preferably 15 to 50 mol %, more preferably 20 to 45 mol %, and even more preferably 25 to 40 mol %, based on the total structural units of the copolymer.

[0073] When the cyclic olefin resin is a terpolymer of a cyclic olefin, a chain olefin, and a vinyl aromatic compound, the content of structural units derived from the chain olefin is usually 5 to 80 mol% of the total structural units of the copolymer, and the content of structural units derived from the vinyl aromatic compound is usually 5 to 80 mol% of the total structural units of the copolymer. Such a terpolymer has the advantage that the amount of expensive cyclic olefin used can be relatively reduced.

[0074] Cyclic olefin resins are commercially available. Examples of commercially available cyclic olefin resins include Topas (registered trademark) (Ticona GmbH, Germany), Arton (registered trademark) (JSR Corporation), ZEONOR (registered trademark) (Zeon Corporation), ZEONEX (registered trademark) (Zeon Corporation), and APEL (registered trademark) (Mitsui Chemicals, Inc.).

[0075] The content of the cyclic olefin resin in the liquid crystal polymer composition of the present invention is 0.1 to 30 parts by mass, preferably 0.5 to 28 parts by mass, more preferably 1 to 27 parts by mass, and even more preferably 2 to 26 parts by mass, relative to 100 parts by mass of the liquid crystal polymer.

[0076] If the content of the cyclic olefin resin is less than 0.1 parts by mass, the dielectric constant and flexibility of the resulting liquid crystal polymer composition are not sufficiently improved, whereas if the content of the cyclic olefin resin is more than 30 parts by mass, the mechanical strength, such as bending strength, of the resulting liquid crystal polymer composition is reduced.

[0077] The liquid crystal polymer composition of the present invention contains, in addition to the liquid crystal polymer and the cyclic olefin resin, a functional group-containing copolymer, where the functional group contained in the functional group-containing copolymer includes a carboxyl group, an acid anhydride, an ester bond, an amide bond, a nitrile group, a carbonyl group, a hydroxyl group, an amino group, an imino group, an ether bond, a nitro group, a halogen group, and an alkyl group.

[0078] The functional group-containing copolymer is a copolymer different from the cyclic olefin resin, and specific examples thereof include maleic anhydride grafted polyolefin copolymer, maleic anhydride grafted polystyrene copolymer, vinyl monomer / maleic anhydride copolymer, epoxy group-containing polyolefin copolymer, epoxy group-containing vinyl random, graft or block copolymer, carboxyl group-containing olefin random or graft copolymer, etc. Among these, copolymers having at least one functional group selected from the group consisting of acid anhydride group, carboxyl group, and epoxy group are preferred, and maleic anhydride grafted polyolefin copolymer and / or epoxy group-containing polyolefin copolymer are more preferred.

[0079] Specific examples of maleic anhydride grafted polyolefin copolymers include maleic anhydride grafted polypropylene (PP-g-MAH), maleic anhydride grafted ethylene / propylene rubber (EPR-g-MAH), and maleic anhydride grafted ethylene / propylene / diene rubber (EPDM-g-MAH).

[0080] Specific examples of maleic anhydride grafted polystyrene copolymers include maleic anhydride grafted polystyrene (PS-g-MAH), maleic anhydride grafted styrene / butadiene / styrene copolymer (SBS-g-MAH), and maleic anhydride grafted styrene / ethylene / butene / styrene copolymer (SEBS-g-MAH).

[0081] Specific examples of vinyl monomer / maleic anhydride copolymers include styrene / maleic anhydride copolymers, styrene / (meth)acrylic acid / maleic anhydride copolymers, (meth)acrylic acid / maleic anhydride copolymers, and (meth)acrylic acid ester / maleic anhydride copolymers.

[0082] Specific examples of epoxy group-containing polyolefin copolymers include ethylene / glycidyl (meth)acrylate copolymer, ethylene / glycidyl (meth)acrylate / vinyl acetate copolymer, ethylene / glycidyl (meth)acrylate / methyl (meth)acrylate copolymer, ethylene / glycidyl (meth)acrylate / ethyl (meth)acrylate copolymer, polystyrene graft copolymer onto ethylene / glycidyl (meth)acrylate copolymer (EGMA or EGA-g-PS), polymethyl (meth)acrylate graft copolymer onto ethylene / glycidyl methacrylate copolymer (EGMA or EGA-g-PMMA), and styrene / acrylonitrile graft copolymer onto ethylene / glycidyl (meth)acrylate copolymer (EGMA or EGA-g-AS).

[0083] Specific examples of epoxy group-containing vinyl random, graft, or block copolymers include glycidyl (meth)acrylate grafted polystyrene (PS-g-GMA or GA), glycidyl (meth)acrylate grafted polymethyl (meth)acrylate (PMMA or PMA-g-GMA), and glycidyl methacrylate grafted polyacrylonitrile (PAN-g-GMA or GA).

[0084] Specific examples of carboxyl group-containing olefin random or graft copolymers include carboxylated polyethylene, carboxylated polypropylene, ethylene / (meth)acrylic acid copolymer (ionomer), and styrene / (meth)acrylic acid copolymer.

[0085] The functional group-containing copolymer contained in the liquid crystal polymer composition of the present invention is preferably a maleic anhydride-grafted polypropylene copolymer and / or an ethylene / glycidyl (meth)acrylate copolymer. Examples of the maleic anhydride-grafted polypropylene copolymer include MG-250P (manufactured by Riken Vitamin, "maleic anhydride-modified polypropylene"), and examples of the ethylene / glycidyl (meth)acrylate copolymer include Bondfast BF-2C (manufactured by Sumitomo Chemical, "ethylene / glycidyl methacrylate copolymer").

[0086] The above-mentioned functional group-containing copolymers may be used alone or in combination of two or more kinds.

[0087] The content of the functional group-containing copolymer in the liquid crystal polymer composition of the present invention is 0.1 to 10 parts by mass, preferably 0.2 to 9 parts by mass, more preferably 0.3 to 8 parts by mass, and even more preferably 0.4 to 7 parts by mass, relative to 100 parts by mass of the liquid crystal polymer.

[0088] If the content of the functional group-containing copolymer is less than 0.1 parts by mass, the dielectric constant and flexibility of the resulting liquid crystal polymer composition are not sufficiently improved, whereas if the content of the functional group-containing copolymer is more than 10 parts by mass, the mechanical strength, such as bending strength, of the resulting liquid crystal polymer composition is reduced.

[0089] The liquid crystal polymer composition of the present invention may further contain, as an optional component, an inorganic and / or organic filler.

[0090] Specific examples of inorganic and / or organic fillers include glass fibers, silica alumina fibers, alumina fibers, carbon fibers, potassium titanate fibers, aluminum borate fibers, aramid fibers, polyarylate fibers, polybenzimidazole fibers, talc, mica, graphite, wollastonite, dolomite, clay, glass flakes, calcium carbonate, barium sulfate, and titanium oxide, which may be used alone or in combination of two or more.

[0091] Among these, talc is preferred because it has an excellent balance between physical properties and cost.

[0092] The inorganic and / or organic filler may be surface-treated, for example, by adsorbing a surface treatment agent onto the filler surface or by adding a surface treatment agent during kneading.

[0093] Examples of surface treatment agents include reactive coupling agents such as silane coupling agents, titanate coupling agents, and borane coupling agents, and lubricants such as higher fatty acids, higher fatty acid esters, higher fatty acid metal salts, and fluorocarbon surfactants.

[0094] When inorganic and / or organic fillers are blended, the content is preferably 1 to 150 parts by mass, and more preferably 10 to 100 parts by mass, per 100 parts by mass of the total amount of the liquid crystal polymer, cyclic olefin resin, and functional group-containing copolymer.

[0095] If the content of the inorganic and / or organic filler is less than 1 part by mass, it is difficult to obtain the effect of improving the mechanical strength and heat resistance of the liquid crystal polymer composition due to the inorganic and / or organic filler, and if it exceeds 150 parts by mass, the fluidity tends to decrease.

[0096] In addition to the liquid crystal polymer, cyclic olefin resin and functional group-containing copolymer, other additives and resin components may be added to the liquid crystal polymer composition of the present invention, as long as the object of the present invention is not impaired.

[0097] Specific examples of other additives include lubricants such as higher fatty acids, higher fatty acid esters, higher fatty acid amides, and higher fatty acid metal salts (here, higher fatty acids refer to those having 10 to 25 carbon atoms), release improvers such as polysiloxanes and fluororesins, colorants such as dyes, pigments, and carbon black, flame retardants, antistatic agents, surfactants, nucleating agents such as talc, organic phosphates, and sorbitols, antiblocking agents, antioxidants such as phosphorus-based antioxidants, phenol-based antioxidants, and sulfur-based antioxidants, weathering agents, heat stabilizers, and neutralizing agents. These additives can be used alone or in combination of two or more.

[0098] The total amount of other additives in the liquid crystal polymer composition is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the total amount of the liquid crystal polymer, cyclic olefin resin, and functional group-containing copolymer.

[0099] If the total amount of other additives is less than 0.01 parts by mass, it is difficult to realize the function of the additives, and if it exceeds 5 parts by mass, the thermal stability of the liquid crystal polymer composition during molding tends to deteriorate.

[0100] Furthermore, when additives such as lubricants, mold release agents, and antiblocking agents are used among the other additives, they may be added when preparing the liquid crystal polymer composition, or may be attached to the pellet surface of the liquid crystal polymer composition during molding.

[0101] Specific examples of other resin components include thermoplastic resins such as polyester, polyacetal, polyphenylene ether and modified products thereof, polysulfone, polyethersulfone, polyetherimide, polyamideimide, etc., and thermosetting resins such as phenol resin, epoxy resin, polyimide resin, etc. These resin components may be used alone or in combination of two or more.

[0102] When other resin components are contained, the content thereof is preferably 0.1 to 100 parts by mass, more preferably 0.2 to 80 parts by mass, per 100 parts by mass of the total amount of the liquid crystal polymer, the cyclic olefin resin, and the functional group-containing copolymer.

[0103] The liquid crystal polymer composition of the present invention can be obtained by mixing a liquid crystal polymer, a cyclic olefin resin, and a functional group-containing copolymer, as well as inorganic and / or organic fillers, other additives, and other resin components, and melt-kneading the mixture using a Banbury mixer, kneader, single-screw or twin-screw extruder, or the like, under temperature conditions ranging from near the crystalline melting temperature of the liquid crystal polymer to 40°C above the crystalline melting temperature.

[0104] The other resin components and other additives may be blended in advance with any of the liquid crystal polymer, the cyclic olefin resin, and the functional group-containing copolymer, or may be blended when molding the liquid crystal polymer composition obtained by melt-kneading the liquid crystal polymer, the cyclic olefin resin, and the functional group-containing copolymer.

[0105] The liquid crystal polymer composition of the present invention thus obtained is characterized by a dielectric constant of 3.60 or less, as measured at 10 GHz using a test piece of 85 mm × 1.7 mm × 1.7 mm by a cavity resonator perturbation method in accordance with JIS C2565. The dielectric constant of the liquid crystal polymer composition of the present invention is preferably 3.58 or less, more preferably 3.56 or less. Furthermore, the dielectric constant is usually 2.50 or more. If the dielectric constant exceeds 3.60, the dielectric properties deteriorate, making it difficult to obtain a molded product with excellent electrical properties.

[0106] The liquid crystal polymer composition of the present invention has a dielectric loss tangent of preferably 0.0011 or less, more preferably 0.0010 or less, even more preferably 0.0008 or less, and particularly preferably 0.0007 or less, measured at 10 GHz using a stick-shaped test piece having a length of 85 mm, a width of 1.75 mm, and a thickness of 1.75 mm. The dielectric loss tangent is usually 0.0001 or more.

[0107] The liquid crystal polymer composition of the present invention is characterized by a maximum strain of 4.5% or more measured using a 65 mm x 12.7 mm x 2.0 mm strip-shaped test piece in a bending test according to ASTM D790. The maximum strain of the liquid crystal polymer composition of the present invention is preferably 4.6% or more, more preferably 4.7% or more. The maximum strain is usually 20% or less. If the maximum strain is less than 4.5%, flexibility decreases, making it difficult to obtain a molded product with excellent flexibility.

[0108] The liquid crystal polymer composition of the present invention has a bending strength in the bending test of preferably 160 MPa or more, more preferably 165 MPa or more, and even more preferably 170 MPa or more. The bending strength is usually 300 MPa or less. The higher the bending strength value, the more easily a molded article can be obtained with maintained or improved mechanical strength.

[0109] The liquid crystal polymer composition of the present invention can be processed into molded articles such as injection molded articles, films, sheets and nonwoven fabrics by conventional molding methods such as injection molding, compression molding, extrusion molding and blow molding.

[0110] The liquid crystal polymer composition of the present invention has excellent dielectric properties, namely a low dielectric constant, and therefore can be suitably used as an electrical and electronic component. Furthermore, since it also has excellent flexibility, it can be suitably used as a material for films, sheets, FPC substrates, etc.

[0111] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. [Example]

[0112] The melt viscosity, bending strength, maximum strain and dielectric constant in the examples were measured by the methods described below.

[0113] <Melt viscosity> The melt viscosity was measured using a melt viscosity measuring device (Capillograph 1D manufactured by Toyo Seiki Co., Ltd.) with a 0.7 mm diameter x 10 mm capillary at a shear rate of 1000 sec -1The melt viscosity was measured at 350°C under the conditions.

[0114] <Bending strength, maximum strain> Using an injection molding machine (MINIMAT M26 / 15 manufactured by Sumitomo Heavy Industries, Ltd.), rectangular test specimens (length 65 mm × width 12.7 mm × thickness 2.0 mm) were molded and used to measure in accordance with ASTM D790. The maximum strain was calculated by measuring the deflection when the stress reached its maximum value in the above measurement. A higher maximum strain indicates better flexibility.

[0115] <Dielectric constant> Using an injection molding machine (Nissei Plastic Industrial Co., Ltd. NEX-15-1E), the cylinder temperature was set at 320°C and the mold temperature at 80°C, and the mixture was molded into stick-shaped test pieces measuring 85 mm in length, 1.7 mm in width, and 1.7 mm in thickness. Using this test piece, the dielectric constant (10 GHz) was measured by the cavity resonator perturbation method in accordance with JIS C2565 using a network analyzer (PNA series E8316A manufactured by Agilent Technologies).

[0116] <Dielectric tangent (tanδ)> Using an injection molding machine (UH1000-110 manufactured by Nissei Plastic Industrial Co., Ltd.), stick-shaped test pieces with a length of 85 mm, a width of 1.75 mm, and a thickness of 1.75 mm were prepared. Using these test pieces, the dielectric loss tangent at 10 GHz was measured by the cavity resonator perturbation method using a vector network analyzer (manufactured by Agilent Technologies).

[0117] In the examples, the following abbreviations represent the following compounds: POB: 4-hydroxybenzoic acid BON6: 6-hydroxy-2-naphthoic acid BP: 4,4'-dihydroxybiphenyl HQ: Hydroquinone TPA: Terephthalic acid

[0118] [Synthesis example 1 (LCP-1)] A reaction vessel equipped with a stirrer with a torque meter and a distillation tube was charged with 660.5 g (54.0 mol%) of BON6, 254.2 g (21.0 mol%) of BP, 14.3 g (2.0 mol%) of HQ, and 248.3 g (23.0 mol%) of TPA, and further charged with 1.03 times the molar amount of acetic anhydride relative to the amount (mol) of hydroxyl groups in all monomers, and deacetic acid polymerization was carried out under the following conditions.

[0119] The temperature was raised from room temperature to 150°C over 1 hour under a nitrogen gas atmosphere and then maintained at 150°C for 60 minutes. The temperature was then raised to 350°C over 7 hours while distilling off the by-product acetic acid, and the pressure was then reduced to 10 mmHg over 90 minutes. The polymerization reaction was terminated when the specified torque was reached, and the contents were removed from the reactor and crushed to obtain liquid-crystalline polyester pellets. The amount of acetic acid distilled during polymerization was nearly the theoretical value. The crystalline melting temperature (Tm) of the resulting pellets measured by DSC was 338°C, and the melt viscosity was 23 Pa·s.

[0120] [Synthesis example 2 (LCP-2)] A reaction vessel equipped with a stirrer with a torque meter and a distillation tube was charged with 655.4 g (73 mol%) of POB and 330.2 g (27 mol%) of BON6, and further charged with 1.02 times the molar amount of acetic anhydride relative to the amount (mol) of hydroxyl groups of all monomers, and deacetic acid polymerization was carried out under the following conditions.

[0121] The temperature was raised from room temperature to 145°C in 1 hour under a nitrogen gas atmosphere and maintained at 145°C for 30 minutes. The temperature was then raised to 320°C over 7 hours while distilling off the by-product acetic acid, and the pressure was then reduced to 10 mmHg over 80 minutes. The polymerization reaction was terminated when the specified torque was reached, and the contents were removed from the reactor and crushed to obtain liquid-crystalline polyester pellets. The amount of acetic acid distilled during polymerization was nearly the theoretical value. The crystalline melting temperature (Tm) of the resulting pellets measured by DSC was 279°C, and the melt viscosity was 21 Pa·s.

[0122] Cyclic olefin resin (COP): Zeon Corporation, cycloolefin polymer "ZEONEX (registered trademark) RS420" Functional group-containing copolymer (BF): Ethylene / glycidyl methacrylate copolymer "Bondfast (registered trademark) BF-2C" manufactured by Sumitomo Chemical Co., Ltd.

[0123] Examples 1 to 4, Comparative Examples 1 to 5 LCP-1, LCP-2, cyclic olefin resin (COP), and functional group-containing copolymer (BF) obtained in Synthesis Examples 1 and 2 were blended in the amounts shown in Table 1, and melt-kneaded at 350°C using a twin-screw extruder (TEX-30, manufactured by Nippon Steel Corporation) to obtain pellets of a liquid crystal polymer composition. The melt viscosity, flexural strength, maximum strain, and dielectric constant were measured using the methods described above. The results are shown in Table 1.

[0124] [Table 1]

[0125] As shown in Table 1, each of the liquid crystal polymer compositions of Examples 1 to 4 was excellent in flexibility (maximum strain) and dielectric constant while maintaining mechanical strength (flexural strength).

[0126] In contrast, the liquid crystal polymer compositions of Comparative Examples 1 to 3 were excellent in mechanical strength but were poor in either or both of flexibility and dielectric constant, and the liquid crystal polymer compositions of Comparative Examples 4 and 5 were significantly impaired in mechanical strength.

Claims

1. The composition contains 100 parts by mass of a liquid crystal polymer, 0.1 to 30 parts by mass of a cyclic olefin resin, and 0.1 to 10 parts by mass of a functional group-containing copolymer, The liquid crystal polymer is represented by the formulas (I) to (III): 【Chemistry 1】 [In the formula, Ar 1 and Ar 2 each represent one or more divalent aromatic groups, and p, q, and r each represent the composition ratio (mol %) of each repeating unit in the liquid crystal polyester (A), and satisfy the following condition: 35≦p≦90, 5≦q≦30, and 5≦r≦30] A liquid crystal polyester (A) containing a repeating unit represented by the formula: Formula (IV) and Formula (V) 【Chemistry 2】 [In the formula, s and t are the composition ratios (mol %) of each repeating unit in the liquid crystal polyester (B), and satisfy the following conditions: 80 / 20≦s / t≦60 / 40] Liquid crystal polyester (B) containing a repeating unit represented by Contains the mass ratio of (A) to (B) [(A) / (B)] is 90 / 10 to 45 / 55; The cyclic olefin resin is a polymer of a cyclic olefin selected from the group consisting of norbornene and polycyclic norbornene, or a copolymer thereof; the functional group-containing copolymer is a copolymer different from the cyclic olefin resin, and is selected from the group consisting of maleic anhydride grafted polyolefin copolymer, maleic anhydride grafted polystyrene copolymer, vinyl monomer / maleic anhydride copolymer, epoxy group-containing polyolefin copolymer, epoxy group-containing vinyl random, graft or block copolymer, and carboxyl group-containing olefin random or graft copolymer; A liquid crystal polymer composition having a maximum strain of 4.5% or more as measured in a bending test in accordance with ASTM D790 using a rectangular test piece of 65 mm x 12.7 mm x 2.0 mm, and a dielectric constant of 3.60 or less as measured at 10 GHz using a test piece of 85 mm x 1.7 mm x 1.7 mm by a cavity resonator perturbation method in accordance with JIS C2565.

2. 2. The liquid crystal polymer composition according to claim 1, wherein the functional group-containing copolymer is a maleic anhydride grafted polyolefin copolymer and / or an epoxy group-containing polyolefin copolymer.

3. A molded article made from the liquid crystal polymer composition according to claim 1 or 2.

4. The molded article according to claim 3 , wherein the molded article is selected from the group consisting of a film, a sheet, and an FPC substrate.

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