Thermoplastic resin composition and method for producing same

Abstract

The resent invention provides a thermoplastic resin composition which achieves low dielectric characteristics that have not been achieved by conventional liquid crystal polymer resin compositions, while maintaining excellent heat resistance and flame retardancy of liquid crystal polymers, and which also has good formability. This thermoplastic resin composition is able to be used for information and communication devices that are used in a high frequency range.　A thermoplastic resin composition which contains a liquid crystal polymer (A) and a modified polyolefin (B) having a polar group, wherein the liquid crystal polymer (A) contains a first liquid crystal polymer (a-1) that has a melting point of less than 300°C and a second liquid crystal polymer (a-2) that has a melting point of 300°C or more. It is preferable for the thermoplastic resin composition that the phase structure is a sea-island structure or a bicontinuous structure, and the second liquid crystal polymer (a-2) is contained in at least a sea phase or a continuous phase.

Description

[Technical Field]

[0001] The present invention relates to a thermoplastic resin composition and a method for producing the same. [Background technology]

[0002] In recent years, there has been a demand for communication devices such as smartphones and electronic devices such as next-generation televisions to transmit and receive large volumes of data at high speeds. This has led to the trend toward higher frequencies for electrical signals. Specifically, in the field of wireless communications, the fifth-generation mobile communication system (5G) is expected to be introduced around 2020. The use of high-frequency bands above 10 GHz is being considered for the introduction of the fifth-generation mobile communication system.

[0003] However, as the frequency of the signals used increases, the quality of the output signal decreases, which can lead to erroneous recognition of information, i.e., transmission loss increases. This transmission loss consists of conductor loss caused by the conductor and dielectric loss caused by the insulating resin that makes up electrical and electronic components such as circuit boards in electronic and communication devices. Since conductor loss is proportional to the 0.5th power of the frequency used and dielectric loss is proportional to the first power of the frequency, the impact of dielectric loss becomes extremely large in high frequency bands, especially in the GHz band.

[0004] Therefore, in order to reduce transmission loss, low-dielectric materials with low dielectric constants and dielectric loss tangents, which are factors related to dielectric loss, are required. In the field of circuit board materials, too, materials with better low-dielectric properties than existing polyimides and epoxy resins are being sought in order to improve signal propagation speed and reduce transmission loss. Heat resistance for solder reflow and the like, flame retardancy, moldability, dimensional stability, and other important required properties are also being considered. For these reasons, the use of liquid crystal polymers, for example, as low-dielectric materials for use in high-frequency bands is being considered.

[0005] However, even lower dielectric properties are required for low-dielectric resins such as liquid crystal polymers to further reduce transmission loss. Liquid crystal polymers also have the problem of being difficult to melt-process due to their anisotropy. For example, when extruding a liquid crystal polymer into a film, a typical film production method, the molten liquid crystal polymer extruded from a die quickly sags due to a decrease in melt viscosity caused by shear forces in the extrusion direction, making the film difficult to pull off. Even if the film can be pulled off, the resulting film is highly susceptible to tearing due to the orientation of the liquid crystal polymer in the film. Furthermore, due to their anisotropy, producing pellets by cutting the strands is difficult. Specifically, for example, the strands may not be cut, or even if they are cut, the cut surface may not be clean, resulting in the formation of whiskers on the pellets. Nonuniform pellet shape and whiskers on the pellets contribute to unstable metering of the liquid crystal polymer during molding and processing. Furthermore, while liquid crystal polymers exhibit high strength, they are also brittle and prone to fracture under certain test conditions.

[0006] In light of these circumstances, compositions have been studied that have improved moldability and anisotropy by blending a liquid crystal polymer with a polyolefin. For example, Patent Document 1 discloses a polymer blend that contains a polyolefin, a liquid crystal polymer, and a compatibilizer such as a grafted polyolefin, and has good tensile strength and impact strength. Patent Document 2 discloses a liquid crystal polymer resin composition with improved flexibility that contains a liquid crystal polymer, an epoxy group-containing ethylene copolymer, and a plate-like filler. Furthermore, Patent Document 3 discloses an aromatic polyester composition that contains a liquid crystal polymer composed of units derived from hydroxybenzoic acid, biphenol, ethylene glycol, and phthalic acid, and an olefin copolymer. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 7-508050 [Patent Document 2] Japanese Patent Application Publication No. 2018-203810 [Patent Document 3] Japanese Patent Application Publication No. 8-012862 Summary of the Invention [Problem to be solved by the invention]

[0008] However, blending a liquid crystal polymer with a polyolefin results in a loss of the inherent heat resistance of the liquid crystal polymer. Liquid crystal polymers and polyolefins generally have low compatibility, making simple blending difficult. Therefore, polyolefins are modified by grafting or copolymerization of polar monomers prior to blending. However, modified polyolefins generally have lower thermal decomposition temperatures than unmodified polyolefins, and when melt-mixed with high-melting liquid crystal polymers, they decompose, causing problems such as foaming during molding. For these reasons, blends of liquid crystal polymers with polyolefins must use low-melting-point liquid crystal polymers, and thermoplastic resin compositions with satisfactory heat resistance have not yet been obtained. Even in the examples of Patent Documents 1 and 2, the liquid crystal polymers used have melting points of around 280°C at most. Patent Document 3 does not disclose the melting point, but the mixing and molding temperature in the examples is 300°C, suggesting that high-melting-point liquid crystal polymers cannot be used.

[0009] Liquid crystal polymers are required to have even lower dielectric constants, and it is expected that their dielectric properties can be improved by blending them with polyolefin resins, which have excellent low dielectric properties. However, due to the compatibility issues mentioned above, alloying with liquid crystal polymers with melting points of 300°C or higher is difficult, and no resin composition has been obtained that exhibits low dielectric properties while maintaining the heat resistance of liquid crystal polymers.

[0010] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a thermoplastic resin composition which has good compatibility and processability of the constituent components, retains the excellent heat resistance and flame retardancy of liquid crystal polymers, and has low dielectric properties that have not been achieved with conventional liquid crystal polymer resin compositions, and can also be used in information and communication devices used in high frequency bands. [Means for solving the problem]

[0011] As a result of intensive research to solve the above problems, the inventors have discovered that by using two types of polymers with different melting points as a liquid crystal polymer, the compatibility between the liquid crystal polymer and the modified polyolefin is improved, and the dielectric constant and dielectric dissipation factor of the liquid crystal polymer are reduced without impairing the heat resistance of the liquid crystal polymer, thereby completing the present invention.

[0012] That is, the present invention provides the following (1) to (3). (8) to provide. (1) A thermoplastic resin composition containing a liquid crystal polymer (A) and a modified polyolefin (B) having a polar group, A thermoplastic resin composition, wherein the liquid crystal polymer (A) contains a first liquid crystal polymer (a-1) having a melting point of less than 300°C and a second liquid crystal polymer (a-2) having a melting point of 300°C or higher. (2) The thermoplastic resin composition according to (1), wherein the phase structure is a sea-island structure in which discontinuous island phases are dispersed in a continuous sea phase, or a co-continuous structure in which two or more components are mixed in their respective continuous phases, and wherein at least the sea phase or the continuous phase contains the second liquid crystal polymer (a-2). (3) The thermoplastic resin composition according to (1) or (2), wherein the polar group is an epoxy group. (4) The thermoplastic resin composition according to any one of (1) to (3), wherein the modified polyolefin (B) having a polar group is a modified polyolefin having a melting point of 200° C. or higher. (5) The thermoplastic resin composition according to any one of (1) to (4), wherein the modified polyolefin (B) having a polar group is modified polymethylpentene. (6) The thermoplastic resin composition according to any one of (1) to (5), wherein the modified polyolefin (B) having a polar group is a graft-modified polyolefin. (7) The thermoplastic resin composition according to any one of (1) to (6), wherein the mass ratio of the liquid crystal polymer (A) to the modified polyolefin having a polar group (B) is 95 / 5 to 55 / 45. (8) A method for producing a thermoplastic resin composition according to any one of (1) to (7), comprising melt-kneading a first liquid crystal polymer (a-1), a second liquid crystal polymer (a-2), and a modified polyolefin (B) having a polar group. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a thermoplastic resin composition that has improved compatibility, good moldability, and low dielectric properties not achieved by conventional liquid crystal polymer resin compositions while maintaining the excellent heat resistance and flame retardancy of liquid crystal polymers. The thermoplastic resin composition of the present invention combines heat resistance such as solder reflow resistance and low dielectric properties, and is suitable for use in information and communication devices used in high frequency bands. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a scanning electron microscope photograph (magnification: 1000 times) of the surface of an extrudate obtained in Example 11 of the thermoplastic resin composition according to the present invention. [Figure 2] 1 is a scanning electron microscope photograph (magnification: 1000 times) of the surface of an extrudate obtained in Example 15 of the thermoplastic resin composition according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] ≪Thermoplastic resin composition≫ The thermoplastic resin composition contains a liquid crystal polymer (A) and a modified polyolefin (B) having a polar group, wherein the liquid crystal polymer (A) contains a first liquid crystal polymer (a-1) having a melting point of less than 300° C. and a second liquid crystal polymer (a-2) having a melting point of 300° C. or higher. Hereinafter, the modified polyolefin (B) having a polar group will also be referred to as “modified polyolefin (B).”

[0016] Taking advantage of its low dielectric properties and high heat resistance, the thermoplastic resin composition is suitable for use in electrical and electronic components used in high frequency bands, information and communication devices, and components for the information and communication devices, etc. Here, low dielectric properties mean that the relative dielectric constant at a frequency of 10 GHz is lower than that of liquid crystal polymers, specifically, for example, 2.9 or less, preferably 2.8 or less, or that the dielectric loss tangent at 10 GHz is 0.0025 or less.

[0017] The thermoplastic resin composition can form various phases depending on various conditions, such as the melting points of the first liquid crystal polymer (a-1), the second liquid crystal polymer (a-2), and the modified polyolefin (B), the difference between their respective melting points, the mixing ratio of each component, the mixing temperature, the type of polar group in the modified polyolefin (B), and the modification rate. Generally, a liquid crystal polymer (a-2) with a melting point of 300°C or higher has poor compatibility with other resins and may even be incompatible with a liquid crystal polymer (a-1) with a melting point below 300°C. However, in a thermoplastic resin composition containing these three components, including the modified polyolefin (B), the three components form a mutually compatible state, resulting in excellent moldability and physical properties.

[0018] The reason why the thermoplastic resin composition exhibits the aforementioned effects may be that the first liquid crystal polymer (a-1) and the modified polyolefin (B) react with each other during the initial mixing stage. Although the modified polyolefin (B) generally has low heat resistance, the polar groups in the thermoplastic resin composition are protected by the aforementioned reaction, making the modified polyolefin less susceptible to decomposition even during high-temperature mixing, thereby enabling it to be mixed with the second liquid crystal polymer (a-2). Furthermore, the aforementioned reaction may produce a polymer in which the first liquid crystal polymer (a-1) with a melting point below 300°C and the modified polyolefin (B) are partially bonded, and this polymer may function as a compatibilizer for the second liquid crystal polymer (a-2). This reaction is thought to result in improved compatibility, resulting in a thermoplastic resin composition that combines the advantages of each component.

[0019] The thermoplastic resin composition preferably has an island-in-a-sea structure or a co-continuous structure, and contains the second liquid crystal polymer (a-2) in at least the sea phase or the continuous phase. The island-in-a-sea structure is a structure consisting of a continuous sea phase and a discontinuous island phase, with the island phase dispersed in the sea phase. The co-continuous structure is a structure in which two or more components are mixed together while each forming a continuous phase.

[0020] In such a phase state, the anisotropy derived from the properties of the liquid crystal polymer (A) is alleviated, and the melt processability of the thermoplastic resin composition is good. In addition, since the liquid crystal polymer (A), particularly the second liquid crystal polymer (a-2), forms a sea component or a continuous phase in the co-continuous structure, the thermoplastic resin composition is likely to exhibit excellent heat resistance derived from the liquid crystal polymer (A).

[0021] The thermoplastic resin composition is produced by mixing a first liquid crystal polymer (a-1), a second liquid crystal polymer (a-2), and a modified polyolefin (B). There are no particular limitations on the mixing method, and a method such as melt-kneading using a single-screw extruder or a twin-screw extruder is preferred. Although a method in which the above-mentioned three components are melt-kneaded simultaneously is preferred, the first liquid crystal polymer (a-1) and the modified polyolefin (B) may be melt-kneaded first, and then the second liquid crystal polymer (a-2) may be mixed.

[0022] The conditions for mixing the first liquid crystal polymer (a-1), the second liquid crystal polymer (a-2), and the modified polyolefin (B) are not particularly limited as long as these components can be mixed uniformly and the components do not undergo excessive thermal decomposition or sublimation. When a melt-kneading device is used, the melt-kneading is preferably carried out at a temperature several tens of degrees Celsius higher than the melting point of the second liquid crystal polymer (a-2), for example, a temperature 5 to 100°C higher than the melting point, more preferably a temperature 10 to 50°C higher than the melting point.

[0023] In the thermoplastic resin composition, the mass ratio of the liquid crystal polymer (A) to the modified polyolefin (B) is not particularly limited. This mass ratio is preferably 95 / 5 to 55 / 45, more preferably 92 / 7 to 70 / 30, and particularly preferably 90 / 10 to 77 / 23. By maintaining the mass ratio within this range, it is easy to obtain a thermoplastic resin composition that combines excellent heat resistance and low dielectric properties. The mass ratio of the first liquid crystal polymer (a-1) to the second liquid crystal polymer (a-2) is also not particularly limited. While the second liquid crystal polymer (a-2) is preferably the main component, any mass ratio can be used depending on the required physical properties and the combination of monomer units constituting the two. As will be described in detail later, for example, a mass ratio of the first liquid crystal polymer (a-1) to the second liquid crystal polymer (a-2) within the range of 3 / 2 to 1 / 10, particularly 1 / 1 to 1 / 5, makes it easy to obtain a thermoplastic resin composition with excellent heat resistance.

[0024] The thermoplastic resin composition may contain other resins besides the liquid crystal polymer (A) and the modified polyolefin (B) to the extent that the object of the present invention is not impaired. The proportion of the total mass of the liquid crystal polymer (A) and the modified polyolefin (B) relative to the total mass of the resin components contained in the thermoplastic resin composition is typically preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and particularly preferably 100 mass%.

[0025] Examples of other resins include unmodified polyolefins, non-liquid crystal polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides, polyesteramides, polyimides, polyamideimides, polycarbonates, polyacetals, polyphenylene sulfides, polyphenylene ethers, polysulfones, polyethersulfones, polyetherimides, silicone resins, and fluororesins.

[0026] The thermoplastic resin composition may contain an inorganic filler as needed. Examples of inorganic fillers include calcium carbonate, talc, clay, silica, magnesium carbonate, barium sulfate, titanium oxide, alumina, montmorillonite, gypsum, glass flakes, glass fiber, milled glass fiber, carbon fiber, alumina fiber, silica-alumina fiber, aluminum borate whisker, and potassium titanate fiber. The inorganic fillers may be used alone or in combination of two or more. The amount of these inorganic fillers used is determined appropriately depending on the application of the thermoplastic resin composition, so long as the low dielectric properties of the thermoplastic resin composition are not impaired. For example, when the thermoplastic resin composition is used to form a film, the upper limit of the amount of inorganic fillers used is determined so long as the mechanical strength of the film is not significantly impaired.

[0027] The thermoplastic resin composition may further contain various additives, such as organic fillers, antioxidants, heat stabilizers, light stabilizers, flame retardants, lubricants, antistatic agents, colorants, rust inhibitors, crosslinking agents, foaming agents, fluorescent agents, surface smoothing agents, surface gloss improvers, and mold release improvers, as needed. These additives may be used alone or in combination of two or more.

[0028] The liquid crystal polymer (A) and the modified polyolefin (B) will be described below.

[0029] <Liquid Crystal Polymer (A)> The liquid crystal polymer (A) is a polymer that exhibits optical anisotropy when melted, and any polymer recognized by those skilled in the art as a thermotropic liquid crystal polymer can be used without particular limitation as long as it has a predetermined melting point described below. The optical anisotropy when melted can be confirmed by a conventional polarization inspection method using crossed polarizers.

[0030] The liquid crystal polymer (A) is typically produced by polycondensation of a monomer mixture containing an acylated monomer having a phenolic hydroxyl group. The polycondensation is preferably carried out in the presence of a catalyst. As described below, the composition of this monomer mixture can be adjusted to prepare the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2), which are components of the thermoplastic resin composition.

[0031] Examples of the catalyst include metal compounds such as magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, potassium acetate, and antimony trioxide, as well as nitrogen-containing heterocyclic compounds such as 1-methylimidazole. The amount of the catalyst used is preferably, for example, 0.1 parts by mass or less per 100 parts by mass of the monomer mixture.

[0032] As described above, the monomer mixture is a mixture of monomers containing an acylated product of a monomer having a phenolic hydroxyl group. The monomer mixture may also contain a monomer not having a phenolic hydroxyl group, such as an aromatic dicarboxylic acid typified by terephthalic acid or isophthalic acid.

[0033] As a method for preparing the monomer mixture, in terms of cost and production time, a method in which a monomer mixture containing a monomer having a phenolic hydroxyl group is acylated to obtain a monomer mixture containing an acylated product of the monomer having a phenolic hydroxyl group is preferred.

[0034] Examples of structural units constituting the liquid crystal polymer include aromatic oxycarbonyl units, aromatic dicarbonyl units, aromatic dioxy units, aromatic aminooxy units, aromatic diamino units, aromatic aminocarbonyl units, and aliphatic dioxy units. The liquid crystal polymer may also contain an amide bond or a thioester bond as a bond other than an ester bond.

[0035] The aromatic oxycarbonyl unit is a unit derived from an aromatic hydroxycarboxylic acid. Specific preferred examples of the aromatic hydroxycarboxylic acid include p-hydroxybenzoic acid, m-hydroxybenzoic acid, o-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, 5-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. Ester derivatives of aromatic hydroxycarboxylic acids, acid halides and other ester-forming derivatives can also be suitably used in the same manner as aromatic hydroxycarboxylic acids. Of these aromatic hydroxycarboxylic acids, p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid are preferred because they allow for easy adjustment of the mechanical properties and melting point of the resulting liquid crystal polymer.

[0036] Aromatic dicarbonyl repeating units are units derived from aromatic dicarboxylic acids. Specific preferred examples of the aromatic dicarboxylic acid 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, and alkyl, alkoxy, or halogen-substituted derivatives thereof. Ester derivatives of aromatic dicarboxylic acids, acid halides and other ester-forming derivatives can also be suitably used in the same manner as aromatic dicarboxylic acids. Of these aromatic dicarboxylic acids, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred because the mechanical properties, heat resistance, melting point temperature, and moldability of the resulting liquid crystal polymer can be easily adjusted to appropriate levels.

[0037] The aromatic dioxy repeating unit is a unit derived from an aromatic diol. Specific preferred examples of aromatic diols include 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 derivatives thereof, and the like. Among these aromatic diols, hydroquinone, resorcinol, and 4,4'-dihydroxybiphenyl are preferred in terms of reactivity during polycondensation and the properties of the resulting liquid crystal polymer.

[0038] The aromatic aminooxy unit is a unit derived from an aromatic hydroxyamine. Specific preferred examples of aromatic hydroxyamines include aromatic hydroxyamines such as p-aminophenol, m-aminophenol, 4-amino-1-naphthol, 5-amino-1-naphthol, 8-amino-2-naphthol, and 4-amino-4'-hydroxybiphenyl, as well as alkyl, alkoxy, or halogen-substituted derivatives thereof.

[0039] The aromatic diamino unit is a unit derived from an aromatic diamine. Specific preferred examples of the aromatic diamine include aromatic diamines such as p-phenylenediamine, m-phenylenediamine, 1,5-diaminonaphthalene, 1,8-diaminonaphthalene, and alkyl, alkoxy, or halogen-substituted derivatives thereof.

[0040] The aromatic aminocarbonyl unit is a unit derived from an aromatic aminocarboxylic acid. Specific preferred examples of aromatic aminocarboxylic acids include aromatic aminocarboxylic acids such as p-aminobenzoic acid, m-aminobenzoic acid, 6-amino-2-naphthoic acid, and alkyl, alkoxy, or halogen-substituted derivatives thereof. Ester derivatives of aromatic aminocarboxylic acids and ester-forming derivatives such as acid halides can also be suitably used as monomers for producing liquid crystal polymers.

[0041] Specific examples of monomers that provide aliphatic dioxy units include aliphatic diols such as ethylene glycol, 1,4-butanediol, and 1,6-hexanediol, as well as acylated products thereof. Furthermore, a polymer containing an aliphatic dioxy unit, such as polyethylene terephthalate or polybutylene terephthalate, can be reacted with the above-mentioned aromatic oxycarboxylic acid, aromatic dicarboxylic acid, aromatic diol, and their acylation products, ester derivatives, acid halides, etc. to obtain a liquid crystal polymer containing an aliphatic dioxy unit.

[0042] The liquid crystal polymer may contain a thioester bond. Monomers that provide such a bond include mercaptoaromatic carboxylic acids, aromatic dithiols, and hydroxyaromatic thiols. The amount of these monomers used is preferably 10 mol % or less based on the total amount of monomers that provide aromatic oxycarbonyl repeating units, aromatic dicarbonyl repeating units, aromatic dioxy repeating units, aromatic aminooxy repeating units, aromatic diamino repeating units, aromatic aminocarbonyl repeating units, aromatic oxydicarbonyl repeating units, and aliphatic dioxy repeating units.

[0043] As described above, it is preferable to acylate a monomer mixture containing a monomer having a phenolic hydroxyl group to obtain a monomer mixture containing an acylated product of the monomer having a phenolic hydroxyl group. The acylation is preferably carried out by reacting the phenolic hydroxyl group with a fatty acid anhydride. Examples of fatty acid anhydrides that can be used include acetic anhydride and propionic anhydride. Acetic anhydride is preferred from the standpoints of cost and ease of handling.

[0044] The amount of fatty acid anhydride used is preferably 1.0 to 1.15 equivalents, more preferably 1.03 to 1.10 equivalents, relative to the amount of phenolic hydroxyl groups.

[0045] A monomer mixture containing a monomer having a phenolic hydroxyl group and the above-mentioned fatty acid anhydride are mixed and heated to carry out acylation, thereby obtaining a monomer mixture containing an acylated product of the monomer having a phenolic hydroxyl group.

[0046] The thus obtained monomer mixture containing the acylated product of the monomer having a phenolic hydroxyl group is heated while the fatty acid produced as a by-product by polycondensation is distilled off, thereby obtaining a liquid crystal polymer. When the liquid crystal polymer is produced only by melt polycondensation, the temperature of the melt polycondensation is preferably 150°C or higher and 400°C or lower, and more preferably 250°C or higher and 370°C or lower. When producing a liquid crystal polymer in two steps, melt polycondensation and solid-state polymerization (described later), the temperature of the melt polycondensation is preferably 120°C or higher and 350°C or lower, and more preferably 200°C or higher and 300°C or lower. The time of the polycondensation reaction is not particularly limited as long as a liquid crystal polymer having a desired melting point or a desired molecular weight can be obtained. For example, the reaction time of the polycondensation is preferably 30 minutes or higher and 5 hours or lower. The liquid crystal polymer produced by the above method may be subjected to polycondensation by heating in a solidified state (solid phase) in order to further increase the molecular weight, if necessary.

[0047] Examples of liquid crystal polymers that can be used as the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2) include the following copolymers 1) to 26). The melting points of the following copolymers 1) to 26) vary depending on the constituent ratio of each monomer and the polymerization method. The following copolymers 1) to 26) include copolymers that can be either the first liquid crystal polymer (a-1) or the second liquid crystal polymer (a-2) depending on the constituent ratio of each monomer and the polymerization method. The melting points of the following copolymers 1) to 26) are disclosed in numerous documents. Therefore, by referring to known documents, the constituent ratio of monomers and the polymerization method for producing a liquid crystal polymer having a desired melting point can be determined. 1) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid copolymer 2) 4-Hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer 3) 4-Hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl copolymer 4) 4-Hydroxybenzoic acid / terephthalic acid / isophthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer 5) 4-hydroxybenzoic acid / terephthalic acid / hydroquinone copolymer 6) 4-Hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer 7) 2-Hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer 8) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer 9) 2-Hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl copolymer 10) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone copolymer 11) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer 12) 4-Hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer 13) 4-Hydroxybenzoic acid / Terephthalic acid / 2,6-Naphthalenedicarboxylic acid / Hydroquinone copolymer 14) 4-Hydroxybenzoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 15) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone copolymer 16) 4-Hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / hydroquinone / 4,4'-dihydroxybiphenyl copolymer 17) 4-Hydroxybenzoic Acid / Terephthalic Acid / 4-Aminophenol Copolymer 18) 2-Hydroxy-6-naphthoic acid / terephthalic acid / 4-aminophenol copolymer 19) 4-Hydroxybenzoic Acid / 2-Hydroxy-6-naphthoic Acid / Terephthalic Acid / 4-Aminophenol Copolymer 20) 4-Hydroxybenzoic Acid / Terephthalic Acid / 4,4'-Dihydroxybiphenyl / 4-Aminophenol Copolymer 21) 4-Hydroxybenzoic acid / terephthalic acid / ethylene glycol copolymer 22) 4-Hydroxybenzoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol copolymer 23) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / ethylene glycol copolymer 24) 4-Hydroxybenzoic acid / 2-hydroxy-6-naphthoic acid / terephthalic acid / 4,4'-dihydroxybiphenyl / ethylene glycol copolymer 25) 4-Hydroxybenzoic acid / terephthalic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl copolymer 26) 2-Hydroxy-6-naphthoic acid / 2,6-naphthalenedicarboxylic acid / 4,4'-dihydroxybiphenyl / hydroquinone copolymer.

[0048] In the thermoplastic resin composition, the liquid crystal polymer (A) can be any combination of a first liquid crystal polymer (a-1) and a second liquid crystal polymer (a-2). The chemical structure and melting point of the liquid crystal polymer (A) used are not particularly limited as long as they satisfy the above-mentioned requirements and do not impair the object of the present invention. From the viewpoint of heat resistance, the melting point of the first liquid crystal polymer (a-1) is preferably 250°C or higher, more preferably 270°C or higher, for example, in the range of 270°C to 290°C. On the other hand, from the viewpoint of processability and suppression of decomposition of the modified polyolefin (B) during production of the thermoplastic resin composition, the melting point of the second liquid crystal polymer (a-2) is preferably 400°C or lower, more preferably 350°C or lower, for example, more preferably in the range of 310°C to 350°C.

[0049] The melting point of the liquid crystal polymer (A) is, for example, the temperature determined from the crystalline melting peak when measured using a differential scanning calorimeter (hereinafter abbreviated as DSC) at a heating rate of 20 ° C. / min. More specifically, after observing the endothermic peak temperature (Tm1) observed when a sample of the liquid crystal polymer is measured under heating conditions of 20 ° C. / min from room temperature, the sample is held at a temperature 20 ° C. to 50 ° C. higher than Tm1 for 10 minutes, and then cooled to room temperature under heating conditions of 20 ° C. / min. After that, the endothermic peak is observed when measured again under heating conditions of 20 ° C. / min. The temperature at the peak top is taken as the melting point of the liquid crystal polymer. For example, a DSC Q1000 manufactured by TA Instruments can be used as the measuring instrument.

[0050] From the viewpoint of heat resistance, it is preferable that both the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2) are fully aromatic liquid crystal polymers. Furthermore, from the viewpoint of further improving compatibility, the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2) may be composed of the same monomer components. As described above, in liquid crystal polymers, even if the combination of monomer mixtures is the same, the melting point can be adjusted by the composition ratio. Therefore, for example, two types of liquid crystal polymers differing only in composition ratio in the combination (26) above may be used as the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2), respectively. In this case, since both components are very similar in terms of chemical structure, compatibility is further improved, and the resulting thermoplastic resin composition can have even better physical properties. Compatibility can also be adjusted by using multiple types of liquid crystal polymers for either or both of the first liquid crystal polymer (a-1) and the second liquid crystal polymer (a-2).

[0051] In the thermoplastic resin composition, the mass ratio of the liquid crystal polymer (A) / (B) modified polyolefin having a polar group is preferably 95 / 5 to 55 / 45 as described above. Furthermore, it is preferable that the second liquid crystal polymer (a-2) is contained at least in the sea phase or continuous phase. Therefore, the content of the second liquid crystal polymer (a-2) is preferably 30% by mass to 85% by mass, particularly 40% by mass to 80% by mass, based on 100% by mass of the entire thermoplastic resin composition. In this case, it is easier to obtain a thermoplastic resin composition with even better heat resistance. There are no particular restrictions on the content of the first liquid crystal polymer (a-1) in the thermoplastic resin composition. The preferred content of the first liquid crystal polymer (a-1) varies depending on the mass ratio of the liquid crystal polymer (A) / modified polyolefin (B) and the chemical structure of each component, but is generally preferably 5% by mass to 50% by mass, particularly preferably 15% by mass to 40% by mass, based on 100% by mass of the thermoplastic resin composition. The mass ratio of the first liquid crystal polymer (a-1) to the second liquid crystal polymer (a-2) is preferably 3 / 2 to 1 / 10, and more preferably 1 / 1 to 1 / 5. Such a composition ratio makes it easy to obtain a thermoplastic resin composition that combines excellent heat resistance and low dielectric properties.

[0052] <Modified polyolefin (B)> The modified polyolefin (B) is not particularly limited as long as it is a resin in which a polyolefin has been modified to have a polar group. A plurality of types of modified polyolefins can also be used in combination. Here, the polar group refers to a polar atomic group, and when this group is present in an organic compound, the compound becomes polar. Specific examples of the polar group that can be introduced into polyolefin include carboxy groups derived from unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid; acid anhydride groups, halocarbonyl groups, carboxylic acid amide groups, imide groups, and carboxylic acid ester groups derived from derivatives of the above-mentioned unsaturated carboxylic acids, such as acid anhydrides, acid halides, amides, imides, and esters; glycidyl methacrylate, glycidyl acrylate, monoglycerin, and the like; Examples of the polar groups include epoxy groups derived from epoxy group-containing vinyl monomers such as glycidyl acrylate, diglycidyl maleate, monoglycidyl itaconate, diglycidyl itaconate, monoglycidyl allylsuccinate, diglycidyl allylsuccinate, glycidyl p-styrenecarboxylate, allyl glycidyl ether, methacrylic glycidyl ether, styrene-p-glycidyl ether, p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, and vinylcyclohexene monoxide. Among these polar groups, it is preferable to contain an epoxy group, since it is easy to obtain a thermoplastic resin composition in a preferred phase state and, when the thermoplastic resin composition is used in contact with other materials, it provides good adhesion between the thermoplastic resin composition and other materials. The epoxy group can react with functional groups of the liquid crystal polymer (A), such as phenolic hydroxyl groups and carboxyl groups, etc. Therefore, the modified polyolefin (B) having an epoxy group as a polar group and the liquid crystal polymer (A), particularly the first liquid crystal polymer (a-1), have a moderate affinity in the thermoplastic resin composition, and can easily form a preferred phase structure, such as a sea-island structure.

[0053] The modified polyolefin (B) is preferably a graft-modified polyolefin having a polar group. Typically, it is a resin obtained by graft-modifying a polyolefin with a vinyl monomer having a polar group in the presence of a radical polymerization initiator. The modified polyolefin (B) is preferably a polyolefin graft-modified with a vinyl monomer having a polar group and an aromatic vinyl monomer, and more preferably a polyolefin graft-modified with glycidyl (meth)acrylate and styrene.

[0054] Examples of polyolefins include linear polyolefins such as polyethylene, polypropylene, poly-1-butene, polyisobutylene, polymethylpentene, propylene-ethylene copolymers, ethylene-propylene-diene copolymers, ethylene / butene-1 copolymers, and ethylene / octene copolymers; and cyclic polyolefins such as copolymers of cyclopentadiene with ethylene and / or propylene.

[0055] Among these polyolefins, polymethylpentene, polyethylene, polypropylene, and propylene-ethylene copolymers are preferred because they are easily modified, and polymethylpentene is more preferred in terms of heat resistance and low dielectric properties.

[0056] Examples of radical polymerization initiators that can be used when modifying, particularly graft-modifying, polyolefins include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide; peroxyketals such as 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(tert-butylperoxy)cyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, and 2,2-bis(tert-butylperoxy)butane; hydroperoxides such as permethane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, and cumene hydroperoxide; dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and α,α'-bis(tert-butylperoxy-m-isopropyl)benzene dialkyl peroxides such as tert-butylcumyl peroxide, di-tert-butyl peroxide, and 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3; diacyl peroxides such as benzoyl peroxide; peroxydicarbonates such as di(3-methyl-3-methoxybutyl)peroxydicarbonate and di-2-methoxybutylperoxydicarbonate; and peroxyesters such as tert-butylperoxyoctate, tert-butylperoxyisobutyrate, tert-butylperoxylaurate, tert-butylperoxy-3,5,5-trimethylhexanoate, tert-butylperoxyisopropylcarbonate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butylperoxyacetate, tert-butylperoxybenzoate, and di-tert-butylperoxyisophthalate. The above radical polymerization initiators can be used alone or in combination of two or more.

[0057] The amount of the radical polymerization initiator used is not particularly limited as long as the modification reaction proceeds well, and is preferably 0.01 to 10 parts by mass, more preferably 0.2 to 5 parts by mass, per 100 parts by mass of the polyolefin.

[0058] Examples of vinyl monomers having a polar group that can be used for the modification include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, and isocrotonic acid; derivatives of these unsaturated carboxylic acids such as acid anhydrides (e.g., maleic anhydride), acid halides, amides, imides, and esters; and epoxy group-containing vinyl monomers such as glycidyl methacrylate, glycidyl acrylate, monoglycidyl maleate, diglycidyl maleate, monoglycidyl itaconate, diglycidyl itaconate, monoglycidyl allyl succinate, diglycidyl allyl succinate, glycidyl p-styrenecarboxylate, allyl glycidyl ether, methacrylic glycidyl ether, styrene-p-glycidyl ether, p-glycidylstyrene, 3,4-epoxy-1-butene, 3,4-epoxy-3-methyl-1-butene, and vinylcyclohexene monoxide. Among these, epoxy group-containing vinyl monomers are preferred, glycidyl methacrylate and glycidyl acrylate are more preferred, and glycidyl methacrylate is particularly preferred.

[0059] The above-mentioned vinyl monomers having a polar group can be used alone or in combination. A modified polyolefin (B) having a polar group can be obtained by grafting these vinyl monomers onto the above-mentioned polyolefins or copolymerizing them during olefin polymerization. The copolymerization method is not particularly limited, and the modified polyolefin (B) may be any copolymer, such as a block copolymer, a random copolymer, an alternating copolymer, or a graft copolymer. However, considering the compatibility effect with the liquid crystal polymer (A), a block copolymer or a graft copolymer, especially a graft copolymer, is preferred. The modified polyolefin (B) is particularly preferably a graft-modified polyolefin in which a monomer, oligomer, or polymer having a polar group as described above is grafted onto a polyolefin backbone, especially a polyolefin molecular chain consisting of a single monomer.

[0060] The amount of the vinyl monomer having a polar group used for modification, particularly graft modification, of the polyolefin is preferably 0.1 to 12 parts by mass, more preferably 0.2 to 8 parts by mass, and particularly preferably 0.5 to 3 parts by mass, per 100 parts by mass of the polyolefin. By using a polyolefin modified with a vinyl monomer having a polar group in an amount within this range, it is easy to obtain a thermoplastic resin composition that is in a preferred phase state and exhibits desired low dielectric properties.

[0061] As mentioned above, the modified polyolefin (B) is particularly preferably a polyolefin graft-modified with a vinyl monomer having a polar group and an aromatic vinyl monomer. By using a vinyl monomer having a polar group in combination with an aromatic vinyl monomer, the grafting reaction is stabilized, making it easier to graft a desired amount of the vinyl monomer having a polar group.

[0062] Specific examples of aromatic vinyl monomers include styrene; alkylstyrenes such as o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene, dimethylstyrene, and trimethylstyrene; chlorostyrenes such as o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, α-chlorostyrene, β-chlorostyrene, dichlorostyrene, and trichlorostyrene; bromostyrenes such as o-bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene, and tribromostyrene; o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, fluorostyrenes such as o-nitrostyrene, m-nitrostyrene, p-nitrostyrene, dinitrostyrene, and trinitrostyrene; nitrostyrenes such as o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene, and trihydroxystyrene; hydroxystyrenes such as o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, o-diisopropenylbenzene, m-diisopropenylbenzene, and p-diisopropenylbenzene; and dialkenylbenzenes such as o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, o-diisopropenylbenzene, m-diisopropenylbenzene, and p-diisopropenylbenzene. Among these aromatic vinyl monomers, styrene, α-methylstyrene, p-methylstyrene, o-divinylbenzene, m-divinylbenzene, p-divinylbenzene, or a mixture of divinylbenzene isomers is preferred from the viewpoint of low cost, and styrene is particularly preferred. The aromatic vinyl monomers can be used alone or in combination of two or more.

[0063] The amount of aromatic vinyl monomer having a polar group used for graft-modifying the polyolefin is preferably 0.1 parts by mass or more and 12 parts by mass or less, more preferably 0.2 parts by mass or more and 8 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 3 parts by mass or less, per 100 parts by mass of the polyolefin.

[0064] The thermoplastic resin compositions described above can be processed into various molded articles by various known manufacturing methods such as injection molding, extrusion molding, and blow molding. The thermoplastic resin composition described above has excellent low dielectric properties in the high frequency band, and is therefore preferably processed into a film, which is used to produce a flexible printed wiring board with low transmission loss. [Example]

[0065] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0066] [Production Example 1] (Production of modified polyolefin B-1) 100 parts by mass of (a1) polymethylpentene resin (TPX grade MX002 manufactured by Mitsui Chemicals) and 0.5 parts by mass of (b1) 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P manufactured by NOF Corp.) were supplied from the hopper port to a twin-screw extruder (46 mmφ, L / D=63, manufactured by Kobe Steel, Ltd.) set at a cylinder temperature of 230°C and a screw rotation speed of 150 rpm, and melt-kneaded. 2 parts by mass of (c1) styrene and 2 parts by mass of (d1) glycidyl methacrylate were then added midway through the cylinder. Subsequently, pellets of the modified polyolefin resin were obtained by vacuum devolatilization through a vent port. The obtained resin pellets were dissolved in xylene at 130°C, and then cooled to room temperature again to precipitate a recrystallized resin. The amount of glycidyl methacrylate modification was measured using an automatic potentiometric titrator (AT700 manufactured by Kyoto Electronics Manufacturing Co., Ltd.) in accordance with JIS K 7236. The amount of glycidyl methacrylate modification in Modified Polyolefin 1 was 0.74% by mass.

[0067] [Production Examples 2 and 3] (Production of Modified Polyolefin B-2 and Modified Polyolefin B-3) Modified polyolefins B-2 and B-3 were produced by the same procedure as in Production Example 1, except that the amounts of (b1) 1,3-di(tert-butylperoxyisopropyl)benzene (Perbutyl P, manufactured by NOF Corp.), (c1) styrene, and (d1) glycidyl methacrylate added were changed as follows: The amount of glycidyl methacrylate modification in each modified polyolefin was as follows: Modified polyolefin 2: (b1) 1.0 part by mass, (c1) 4 parts by mass, (d1) 4 parts by mass: glycidyl methacrylate modification amount 1.77% by mass Modified polyolefin 3: (b1) 1.0 part by mass, (c1) 6 parts by mass, (d1) 6 parts by mass: glycidyl methacrylate modification amount 1.94% by mass

[0068] [Examples 1 to 15 and Comparative Examples 1 to 9] In the examples and comparative examples, a wholly aromatic liquid crystal polyester resin A-1 having a melting point of 280°C was used as the first liquid crystal polymer (a-1), a wholly aromatic liquid crystal polyester resin A-2 having a melting point of 320°C was used as the second liquid crystal polymer (a-2), and modified polyolefins B-1 to B-3 obtained in Production Examples 1 to 3 were used as the modified polyolefin (B).

[0069] The amounts of each material listed in Tables 1 to 3 were fed through the hopper into a twin-screw extruder (25 mm diameter, L / D=40, manufactured by Technovel) set at a cylinder temperature of 340°C and a screw rotation speed of 150 rpm, and melt-kneaded to obtain the resin compositions of each Example and Comparative Example. Comparative Example 1 was an evaluation of the liquid crystal polymer A-2 alone. The appearance of the extrudate (strand) of each resin or resin composition of each Example and Comparative Example was observed, and moldability was evaluated by assigning an X to those exhibiting foaming or gelation and an O to those exhibiting no such problems. The dielectric constant, dielectric loss tangent, and heat resistance were also evaluated according to the following methods. The evaluation results are shown in Tables 1 to 3.

[0070] [Dielectric constant / dielectric loss tangent] The dielectric constant and dielectric loss tangent of the obtained resin composition were measured at the following frequencies using a cavity resonator perturbation method complex dielectric constant evaluation device. Measurement frequency: 10GHz Measurement conditions: temperature 22℃~24℃, humidity 45%~55% Measurement sample: A sample that had been left to stand for 24 hours under the above measurement conditions was used.

[0071] [Heat resistance] A dynamic viscoelasticity measuring device was used as the measuring device, and the storage modulus was 10 7 The temperature (°C) at which the compressive strength reached or reached 50 MPa was measured. Temperatures of 300°C or higher were evaluated as ◯, and temperatures below 300°C were evaluated as x. Sample measurement range: width 5mm, distance between grips 20mm Measurement temperature range: 25℃~310℃ Heating rate: 5℃ / min Distortion amplitude: 0.1% ·Measurement frequency; 1Hz Minimum tension / compression force: 0.1g Initial force amplitude: 100g

[0072] [Phase structure] The phase structure of some of the compositions was confirmed by microscopic observation. The observation results were classified according to the following criteria. The results are shown in Tables 1 to 3. Figures 1 and 2 (Examples 11 and 15) are examples of these microscopic photographs. A: Sea-island structure (component (A) is the sea phase) B: Sea-island structure (component (A) is an island phase) C: Bicontinuous structure (part of the continuous region contains islands) D: Phase separation

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] The examples show that thermoplastic resins containing a first liquid crystal polymer (a-1) having a melting point of less than 300°C, a second liquid crystal polymer (a-2) having a melting point of 300°C or more, and a modified polyolefin (B) having a polar group combine high heat resistance, favorable low dielectric properties, and excellent molding processability. In particular, the thermoplastic resin compositions of Examples 2 to 5, in which the content of the first liquid crystal polymer is 15% by mass or more and 40% by mass or less, exhibit a good balance of heat resistance, low dielectric properties, and molding processability. Figure 1 is a scanning electron microscope photograph (1000x magnification) of the surface of the extrudate obtained in Example 11. It can be seen that the resin components are uniformly dispersed, forming a sea-island structure with a salami-like structure.

[0077] On the other hand, the thermoplastic resin compositions of Comparative Examples 2 to 8 and 11, which did not contain a first liquid crystal polymer (a-1) having a melting point of less than 300°C, exhibited foaming and gelation during molding, even when the amount of modification and blending ratio of the modified polyolefin (B) were adjusted, and molded articles suitable for physical property testing could not be obtained. The results of these Comparative Examples suggest that when a second liquid crystal polymer (a-2) having a melting point of 300°C or higher and a modified polyolefin (B) are melt-kneaded without the addition of a first liquid crystal polymer (a-1) having a melting point of less than 300°C, the modified polyolefin is significantly degraded. In Comparative Examples 9 and 10, extrudates with satisfactory appearance were obtained, but their heat resistance was insufficient. On the other hand, the thermoplastic resin compositions of Examples 1 to 7 and 12, which contained approximately the same amount of modified polyolefin (B) as the thermoplastic resin compositions of these Comparative Examples, exhibited good strand moldability and low dielectric properties. The thermoplastic resin compositions of Examples 6, 7, and 13 to 15 have good heat resistance despite the liquid crystal polymer A-2 content being 30 to 40% by mass. This is presumably because the second liquid crystal polymer (a-2) having a melting point of 300°C or higher is contained in the sea phase or continuous phase. Figure 2 is a scanning electron microscope photograph (1000x magnification) of the surface of the extrudate obtained in Example 15. It can be seen that a bicontinuous structure with island phases is formed in some areas.

Claims

1. A thermoplastic resin composition containing a liquid crystal polymer (A) and a modified polyolefin (B) having a polar group, The liquid crystal polymer (A) contains a first liquid crystal polymer (a-1) having a melting point of less than 300°C and a second liquid crystal polymer (a-2) having a melting point of 300°C or higher, and The modified polyolefin (B) is a modified polymethylpentene. Thermoplastic resin composition.

2. 2. The thermoplastic resin composition according to claim 1, wherein the phase structure is a sea-island structure in which discontinuous island phases are dispersed in a continuous sea phase, or a co-continuous structure in which continuous phases of two or more components are mixed together, and the thermoplastic resin composition contains the second liquid crystal polymer (a-2) in at least the sea phase or the continuous phase.

3. The thermoplastic resin composition according to claim 1 or 2, wherein the polar group is an epoxy group.

4. The thermoplastic resin composition according to any one of claims 1 to 3, wherein the modified polyolefin (B) is a modified polyolefin having a melting point of 200°C or higher.

5. The thermoplastic resin composition according to any one of claims 1 to 4, wherein the modified polyolefin (B) is a graft-modified polyolefin.

6. The thermoplastic resin composition according to any one of claims 1 to 5, wherein the mass ratio of the liquid crystal polymer (A) to the modified polyolefin (B) is 95 / 5 to 55 / 45.

7. A method for producing a thermoplastic resin composition described in any one of claims 1 to 6, comprising melt-kneading the first liquid crystal polymer (a-1), the second liquid crystal polymer (a-2), and the modified polyolefin (B).

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