Liquid crystal resin composition and connector using same

Abstract

Provided are: a liquid crystalline resin composition which provides a molded article having excellent mechanical strength and suppressed blistering, and which has good flowability and mold release properties; and a connector which uses the liquid crystalline resin composition. A liquid crystalline resin composition according to the present invention contains (A) a liquid crystalline resin, (B) whiskers, (C) an epoxy group-containing olefin polymer, and (D) a polyol fatty acid ester, the content of the (B) whiskers being 20-40% by mass, the content of the (C) epoxy group-containing olefin polymer being 0.5-6% by mass, and the content of the (D) polyol fatty acid ester being 0.5-6% by mass relative to the entire liquid crystalline resin composition. And the content of the (D) polyol fatty acid ester is 0.1-2.0 mass%. The liquid crystalline resin composition according to the present invention further contains (E) a plate-like filler, and the content of the (E) plate-like filler is 5-15 mass% relative to the entire liquid crystalline resin composition. A molded article according to the present invention contains the liquid crystalline resin composition. The connector provided by the invention comprises the molded body.

Description

Technical Field

[0001] The present invention relates to a liquid crystalline resin composition and a connector using the same. Background Art

[0002] Liquid crystalline resins, such as liquid crystalline polyester resins, have excellent well-balanced mechanical strength, heat resistance, chemical resistance, electrical properties, and dimensional stability, and are therefore widely used as high-performance process plastics.

[0003] In particular, with the recent miniaturization and thinning of optoelectronic devices, there is a demand for thinner and narrower-pitch electronic components (such as connectors) that constitute these devices. For example, Patent Document 1 discloses a connector formed from a liquid crystal resin composition reinforced with mica and glass fiber. This connector is used as a substrate-to-substrate (B-to-B) connector, which requires heat resistance, warpage suppression, and dimensional stability, and is used as an FPC connector for connecting flexible printed circuit boards (FPCs) and flexible flat cables (FFCs).

[0004] Liquid crystal resin compositions can also cause blistering. Liquid crystal polymers such as liquid crystal polyesters and liquid crystal polyesteramides have excellent high-temperature thermal stability and are therefore often used in materials requiring high-temperature heat treatment. However, if molded articles are left in hot air or liquid for extended periods, small surface swellings known as blisters may develop.

[0005] One reason for this phenomenon is that decomposition gases, such as those generated when the liquid crystal polymer is molten, are drawn into the molded article. Subsequently, during high-temperature heat treatment, these gases expand and push up against the surface of the molded article, which has softened due to the heat. The pushed-up areas sometimes appear as bubbles. For example, Patent Document 2 discloses a liquid crystal resin composition that reduces the occurrence of bubbles due to this phenomenon. The composition contains a liquid crystal polyester, a specific fatty acid ester, a filler, and a fatty acid metal salt.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-37061

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2009-179693 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] According to the inventors' research, conventional liquid crystal resin compositions for connector molding suffer from insufficient fluidity and mold release properties, as well as poor processability. This makes it difficult to manufacture connectors that meet the demands for thinner profiles and narrower pitches. Furthermore, it's difficult to obtain molded articles with a good balance between mechanical strength and blister resistance from conventional liquid crystal resin compositions.

[0012] The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide a liquid crystalline resin composition having excellent mechanical strength, a molded body with suppressed foaming, good fluidity and releasability, and a connector using the same.

[0013] Solutions for solving problems

[0014] The present inventors have conducted extensive research to address the above-mentioned issues. As a result, they discovered that the above-mentioned issues can be addressed by using a liquid crystalline resin composition containing a liquid crystalline resin, whiskers, an epoxy-containing olefin polymer, and a polyol fatty acid ester in specific proportions, leading to the completion of the present invention. More specifically, the present invention provides the following solutions.

[0015] (1) A liquid crystal resin composition comprising:

[0016] (A) liquid crystal resin,

[0017] (B) Whiskers,

[0018] (C) an epoxy group-containing olefin polymer, and

[0019] (D) polyol fatty acid esters,

[0020] With respect to the entire liquid crystal resin composition,

[0021] The content of the whiskers (B) is 20 to 40% by mass.

[0022] The content of the epoxy group-containing olefin polymer (C) is 0.5 to 6% by mass.

[0023] The content of the (D) polyol fatty acid ester is 0.1 to 2.0% by mass.

[0024] (2) The liquid crystalline resin composition according to (1), wherein the liquid crystalline resin (A) is an aromatic polyester or aromatic polyester amide having as a constituent a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

[0025] (3) The liquid crystalline resin composition according to (1) or (2), wherein the (D) polyol fatty acid ester is at least one selected from the group consisting of fatty acid esters of pentaerythritol and fatty acid esters of dipentaerythritol.

[0026] (4) The liquid crystalline resin composition according to any one of (1) to (3), wherein the content of the (B) whiskers is 25 to 40% by mass based on the entire liquid crystalline resin composition.

[0027] (5) The liquid crystalline resin composition according to any one of (1) to (4), further comprising (E) a plate-like filler.

[0028] The content of the (E) plate-like filler is 5 to 15% by mass based on the entire liquid crystalline resin composition.

[0029] (6) The liquid crystalline resin composition according to any one of (1) to (5), which is used for a connector.

[0030] (7) Use of the liquid crystalline resin composition according to any one of (1) to (5) for producing a connector.

[0031] (8) A molded article comprising the liquid crystalline resin composition according to any one of (1) to (5).

[0032] (9) A connector comprising the molded article described in (8).

[0033] Effects of the Invention

[0034] The molded article formed from the liquid crystalline resin composition of the present invention is excellent in mechanical strength and releasability, and the occurrence of foaming is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 (a) is a perspective view showing a U-shaped liquid crystal resin molded body used in the evaluation of releasability performed in Examples. Figure 1 (b) is a side view showing the U-shaped liquid crystal resin molded body. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments.

[0037] <Liquid Crystal Resin Composition>

[0038] The liquid crystalline resin composition of the present invention contains (A) a liquid crystalline resin, (B) whiskers, (C) an epoxy group-containing olefin polymer, and (D) a polyol fatty acid ester.

[0039] [(A) Liquid Crystal Resin]

[0040] The (A) liquid crystalline resin used in the present invention refers to a melt-processable polymer having the property of forming an optically anisotropic melt phase. The property of the anisotropic melt phase can be confirmed by a conventional polarization detection method using crossed polarizers. More specifically, the confirmation of the anisotropic melt phase can be implemented by observing a molten sample placed on a Leitz hot stage using a Leitz polarizing microscope at a magnification of 40 times under a nitrogen atmosphere. When the liquid crystalline polymer that can be used in the present invention is detected between crossed polarizers, polarized light is usually transmitted even in a molten static state, and optically shows anisotropy.

[0041] The type of the liquid crystalline resin (A) as described above is not particularly limited, but is preferably an aromatic polyester and / or an aromatic polyester amide. Furthermore, polyesters partially containing aromatic polyesters and / or aromatic polyester amides in the same molecular chain also fall within this range. As the liquid crystalline resin (A), a resin having a logarithmic viscosity (IV) of preferably at least about 2.0 dl / g, more preferably 2.0 to 10.0 dl / g, when dissolved in pentafluorophenol at a concentration of 0.1% by mass at 60°C is preferably used.

[0042] The aromatic polyester or aromatic polyester amide as the (A) liquid crystalline resin usable in the present invention is particularly preferably an aromatic polyester or aromatic polyester amide having as a constituent a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

[0043] More specifically, we can cite:

[0044] (1) A polyester mainly composed of structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof;

[0045] (2) a polyester mainly composed of (a) a structural unit derived from at least one member selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, and (b) a structural unit derived from at least one member selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof;

[0046] (3) a polyester mainly composed of (a) a structural unit derived from at least one member selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, (b) a structural unit derived from at least one member selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids and derivatives thereof, and (c) a structural unit derived from at least one member selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols and derivatives thereof;

[0047] (4) a polyester amide mainly composed of (a) a structural unit derived from at least one member selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, (b) a structural unit derived from at least one member selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and derivatives thereof, and (c) a structural unit derived from at least one member selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof;

[0048] (5) Polyester amides mainly composed of (a) structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, (b) structural units derived from at least one selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and derivatives thereof, (c) structural units derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof, and (d) structural units derived from at least one selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols, and derivatives thereof. Furthermore, a molecular weight modifier may be used in combination with the above-mentioned components as needed.

[0049] In the liquid crystalline resin (A), the content of structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof is preferably 45 mol% or more, more preferably 50 mol% or more, further more preferably 55 mol% or more, even more preferably 60 mol% or more, and particularly preferably 62 mol% or more relative to all structural units, from the viewpoint of minimizing changes in the molecular structure of the liquid crystalline resin (A). The upper limit of the above content is not particularly limited and may be 100 mol% or less, 90 mol% or less, 80 mol% or less, 75 mol% or less, or 70 mol% or less relative to all structural units.

[0050] Preferred examples of specific compounds constituting the liquid crystalline resin (A) useful in the present invention include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid; aromatic diols such as 2,6-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcinol, compounds represented by the following general formula (I), and compounds represented by the following general formula (II); aromatic dicarboxylic acids such as 1,4-phthalic acid, 1,3-phthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and compounds represented by the following general formula (III); and aromatic amines such as p-aminophenol, p-phenylenediamine, and N-acetyl-p-aminophenol. Among the aromatic hydroxycarboxylic acids and their derivatives, 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, or a combination thereof are preferred from the viewpoints of reactivity and the stability of the molecular structure of the liquid crystalline resin (A).

[0051]

[0052] (X: is a group selected from alkylene (C1-C4), alkylidene, -O-, -SO-, -SO2-, -S- and -CO-.)

[0053]

[0054] (Y: is selected from -(CH2) n -(n=1~4) and -O(CH2) n O-(n=1 to 4)

[0055] The preparation of the (A) liquid crystal resin used in the present invention can be carried out by a known method from the above-mentioned monomer compound (or mixture of monomers) using a direct polymerization method or an ester exchange method. Melt polymerization, solution polymerization, slurry polymerization, solid phase polymerization, or a combination of two or more of these methods are generally used. Preferably, melt polymerization or a combination of melt polymerization and solid phase polymerization is used. The above-mentioned compounds having ester-forming ability can be used directly for polymerization. Alternatively, they can be modified from precursors to derivatives having ester-forming ability in the previous stage of polymerization. Various catalysts can be used when performing these polymerizations. Representative catalysts include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, tris(2,4-heptanedione) cobalt (III), and organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine. The amount of the catalyst used is generally preferably about 0.001 to 1% by mass, particularly preferably about 0.01 to 0.2% by mass, relative to the total mass of the monomer. The molecular weight of the polymer produced by these polymerization methods can be further increased by a solid phase polymerization method in which the polymer is heated under reduced pressure or in an inert gas, if necessary.

[0056] The melt viscosity of the liquid crystal resin (A) obtained by the above method is not particularly limited. Generally, the melt viscosity at the molding temperature can be used. -1 The viscosity of the liquid crystal resin is preferably 3 Pa·s or more and 500 Pa·s or less. However, a resin with a high viscosity is not preferred because its fluidity is greatly deteriorated. It should be noted that the liquid crystal resin (A) may be a mixture of two or more liquid crystal resins.

[0057] The content of the liquid crystalline resin (A) relative to the total mass of the liquid crystalline resin composition of the present invention is preferably 52 to 79.4 mass% or 37 to 74.4 mass%, more preferably 53.5 to 74.05 mass% or 40.5 to 68.05 mass%, and even more preferably 62 to 73.75 mass% or 50 to 65.75 mass%. When the content of component (A) is within the above range, it is preferred in terms of fluidity, heat resistance, etc.

[0058] [(B) Whiskers]

[0059] The liquid crystalline resin composition of the present invention contains whiskers. By including whiskers in the liquid crystalline resin composition of the present invention, the mechanical strength of the molded article can be easily improved while maintaining the fluidity of the liquid crystalline resin composition. In this specification, whiskers refer to mineral fibers, more specifically, needle-shaped single crystals. Whiskers can be used alone or in combination of two or more.

[0060] The average fiber length of the (B) whiskers is preferably 5 to 200 μm, more preferably 7 to 170 μm, and even more preferably 9 to 150 μm. If the above-mentioned average fiber length is within the above-mentioned range, the mechanical strength of the molded body is more easily improved. It should be noted that, in this specification, the average fiber length of the (B) whiskers is an average value obtained as follows: 10 stereomicroscope images of the whiskers are collected from a CCD camera to a PC, and an image measuring machine is used, according to an image processing method, for each stereomicroscope image, the fiber length of 100 whiskers, i.e., a total of 1000 whiskers, is measured to obtain the average value. The average fiber length of the (B) whiskers in the liquid crystalline resin composition is measured as follows: the whiskers remaining after the liquid crystalline resin composition is ashed by heating at 600°C for 2 hours are measured by applying the above-mentioned method.

[0061] The fiber diameter of the (B) whisker is preferably 0.2 to 15 μm or less, more preferably 0.25 to 10 μm. If the fiber diameter is within the above range, the mechanical strength of the molded body is more easily improved. It should be noted that, in this specification, the fiber diameter of the (B) whisker is the average of the values obtained by observing the whiskers with a scanning electron microscope and measuring the fiber diameters of 30 whiskers. The fiber diameter of the (B) whisker in the liquid crystalline resin composition is measured as follows: the above method is applied to the whiskers remaining after the liquid crystalline resin composition is ashed by heating at 600°C for 2 hours, thereby measuring

[0062] The aspect ratio of the whiskers (B), that is, the value of average fiber length / fiber diameter, is preferably 8 or more, more preferably 10 to 100, and even more preferably 15 to 75, from the viewpoint of mechanical strength of a molded body such as a connector containing the liquid crystalline resin composition of the present invention.

[0063] The whiskers (B) are not particularly limited, and examples thereof include potassium titanate whiskers, calcium silicate whiskers (wollastonite), calcium carbonate whiskers, zinc oxide whiskers, aluminum borate whiskers, silicon nitride whiskers, silicon trinitride whiskers, basic magnesium sulfate whiskers, barium titanate whiskers, silicon carbide whiskers, and boron whiskers. In terms of availability, potassium titanate whiskers, calcium silicate whiskers (wollastonite), calcium carbonate whiskers, zinc oxide whiskers, and aluminum borate whiskers are preferred, and potassium titanate whiskers and calcium silicate whiskers (wollastonite) are more preferred.

[0064] The content of component (B) is 20 to 40% by mass relative to the total mass of the liquid crystal resin composition of the present invention. When the content of component (B) is within the above range, the mechanical strength of the molded article is easily improved while maintaining the fluidity of the liquid crystal resin composition. The content of component (B) is preferably 22.5 to 40% by mass, more preferably 25 to 35% by mass, and even more preferably 25 to 32.5% by mass.

[0065] [(C) Epoxy-containing olefin polymer]

[0066] The liquid crystalline resin composition of the present invention contains (C) an epoxy-containing olefin polymer. When the liquid crystalline resin composition of the present invention contains (C) an epoxy-containing olefin polymer, the mechanical strength and blister resistance of the molded article are well-balanced and easily improved while maintaining the excellent releasability of the liquid crystalline resin composition of the present invention.

[0067] Examples of epoxy-containing olefin polymers include copolymers composed of repeating units derived from α-olefins and repeating units derived from glycidyl esters of α,β-unsaturated acids. Epoxy-containing olefin polymers may be used alone or in combination of two or more.

[0068] The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, butene, etc., among which ethylene is preferably used. The glycidyl ester of an α,β-unsaturated acid is represented by the following general formula (IV). In the following general formula (IV), R' represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or -R 1 -COOH group, R 1 represents an alkylene group having 1 to 5 carbon atoms. Examples of the glycidyl ester of an α,β-unsaturated acid include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, and glycidyl itaconate, with glycidyl methacrylate being particularly preferred.

[0069]

[0070] The epoxy-containing olefin polymer preferably contains 87 to 98% by mass of repeating units derived from an α-olefin and 13 to 2% by mass of repeating units derived from a glycidyl ester of an α,β-unsaturated acid.

[0071] The epoxy-containing olefin polymer may contain, in addition to the above two components, 0 to 48 parts by mass of repeating units derived from one or more olefinic unsaturated monomers such as acrylonitrile, acrylic acid ester, methacrylic acid ester, α-methylstyrene, maleic anhydride, etc. as a third component, within the scope not impairing the present invention.

[0072] Epoxy-containing olefin polymers can be easily produced using monomers corresponding to the respective components and a free radical polymerization catalyst using conventional free radical polymerization methods. More specifically, they can generally be produced by copolymerizing an α-olefin with a glycidyl ester of an α,β-unsaturated acid in the presence of a free radical generator at 500 to 4000 atmospheres, at 100 to 300°C, in the presence or absence of a suitable solvent and a chain transfer agent. Alternatively, they can be produced by mixing an α-olefin with a glycidyl ester of an α,β-unsaturated acid and a free radical generator, followed by melt graft copolymerization in an extruder.

[0073] The content of the epoxy-containing olefin polymer (C) is 0.5 to 6% by mass, preferably 0.75 to 5.5% by mass, and more preferably 1 to 5% by mass, relative to the total mass of the liquid crystalline resin composition of the present invention. When the content of component (C) is within this range, the molded article tends to have a well-balanced mechanical strength and blister resistance while maintaining the excellent releasability of the liquid crystalline resin composition.

[0074] [(D) Polyol fatty acid ester]

[0075] The liquid crystalline resin composition of the present invention includes (D) a polyol fatty acid ester. Including (D) a polyol fatty acid ester improves the releasability of the liquid crystalline resin composition, and the mechanical strength and blister resistance of the molded article are improved. The polyol fatty acid esters (D) may be used alone or in combination of two or more.

[0076] (D) Polyol fatty acid esters are partial esters or full esters formed by condensation of fatty acids with polyols. Partial esters are those in which some of the hydroxyl groups of a polyol are acylated with fatty acids, while full esters are those in which all of the hydroxyl groups of a polyol are acylated with fatty acids.

[0077] As fatty acids, higher fatty acids having 10 to 32 carbon atoms are preferred. Examples of fatty acids include saturated fatty acids such as decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid (palmitic acid), heptadecanoic acid, octadecanoic acid (stearic acid), nonadecanoic acid, eicosanoic acid, docosanoic acid, and hexacosanoic acid; and unsaturated fatty acids such as palmitoleic acid, oleic acid, linoleic acid, linolenic acid, eicosenoic acid, eicosapentaenoic acid, and docosenoic acid. Fatty acids may be used alone or in combination of two or more. Fatty acids having 10 to 22 carbon atoms are preferred, and fatty acids having 14 to 20 carbon atoms are more preferred.

[0078] A polyol is a compound having two or more alcoholic hydroxyl groups within its molecule. Preferred polyols include those having 3 to 32 carbon atoms. Examples of polyols include polyglycerols such as glycerol, diglycerol, and decaglycerol; pentaerythritol; dipentaerythritol; diethylene glycol; and propylene glycol. Polyols may be used alone or in combination of two or more. Pentaerythritol and dipentaerythritol are particularly preferred polyols in terms of the heat resistance of the resulting polyol fatty acid ester.

[0079] Examples of the polyol fatty acid ester (D) include fatty acid esters of pentaerythritol and fatty acid esters of dipentaerythritol. In terms of the good balance and easy improvement in the mechanical strength, blister resistance, and mold releasability of a molded article comprising the liquid crystalline resin composition, pentaerythritol tetrapalmitate, dipentaerythritol tetrapalmitate, pentaerythritol tetrastearate, and dipentaerythritol tetrastearate are preferred, and pentaerythritol tetrastearate and dipentaerythritol tetrastearate are more preferred.

[0080] (D) Polyol fatty acid esters can be obtained by esterifying polyols with fatty acids through dehydration polycondensation. It should be noted that, during esterification, the amount of hydroxyl groups in the polyol and the amount of fatty acids can be appropriately adjusted to obtain partial esters or full esters.

[0081] (D) The 5% weight loss temperature (TB) of the polyol fatty acid ester determined by thermogravimetric analysis (TGA) is preferably 250°C or higher, more preferably 280°C or higher. When the 5% weight loss temperature is 250°C or higher, the polyol fatty acid ester is less likely to be thermally decomposed during molding of the composition.

[0082] The content of (D) polyol fatty acid ester is 0.1 to 2.0% by mass relative to the entire liquid crystalline resin composition. If the content of (D) polyol fatty acid ester is within the above range, the releasability of the liquid crystalline resin composition is easily improved, and the mechanical strength and foaming resistance of the molded article are easily improved. The content of (D) polyol fatty acid ester is preferably 0.15 to 1.5% by mass, more preferably 0.2 to 1.0% by mass, and even more preferably 0.25 to 0.5% by mass relative to the entire liquid crystalline resin composition.

[0083] [(E) Plate-like filler]

[0084] The liquid crystalline resin composition of the present invention may also contain a platy filler. The inclusion of a platy filler in the liquid crystalline resin composition of the present invention facilitates obtaining a molded article having suppressed anisotropy while maintaining excellent mechanical strength. The platy fillers may be used alone or in combination of two or more.

[0085] The median particle size of the (E) component is preferably 10 to 50 μm. If the above-mentioned median particle size is within the above-mentioned range, it is further easy to obtain a molded body having suppressed anisotropy while maintaining excellent mechanical strength from the obtained composition. The above-mentioned median particle size is preferably 15 to 40 μm, more preferably 20 to 30 μm. It should be noted that, in this specification, the median particle size of the (E) component refers to the central value of the volume basis measured by the laser diffraction / scattering particle size distribution measurement method. The median particle size of the (E) component in the liquid crystalline resin composition is measured as follows: the above-mentioned method is applied to the (E) component remaining after the liquid crystalline resin composition is ashed by heating at 600°C for 2 hours.

[0086] The content of the (E) platy filler is preferably 5 to 15% by mass relative to the total mass of the liquid crystalline resin composition of the present invention. When the content of the (E) platy filler is within this range, it is easier to obtain a molded article from the resulting composition while maintaining excellent mechanical strength and suppressing anisotropy. The content of the (E) platy filler is more preferably 6 to 13% by mass, and even more preferably 8 to 12% by mass.

[0087] Examples of the plate-like filler in the present invention include talc, mica, glass flakes, and various metal foils. In order to suppress the anisotropy of a molded article obtained from the liquid crystalline resin composition without deteriorating the fluidity of the liquid crystalline resin composition, at least one member selected from the group consisting of talc and mica is preferred, with mica being more preferred.

[0088] 〔talc〕

[0089] The talc that can be used in the present invention preferably has a total content of Fe2O3, Al2O3, and CaO of 2.5% by mass or less, a total content of Fe2O3 and Al2O3 exceeding 1.0% by mass and falling below 2.0% by mass, relative to the total solids content of the talc, and a CaO content of less than 0.5% by mass. In other words, the talc that can be used in the present invention may contain at least one of Fe2O3, Al2O3, and CaO in addition to SiO2 and MgO, which are its main components, with each component contained within the above-mentioned content ranges.

[0090] When the total content of Fe₂O₃, Al₂O₃, and CaO in the talc is 2.5% by mass or less, the moldability of the liquid crystal resin composition and the heat resistance of a molded article obtained from the liquid crystal resin composition are less likely to deteriorate. Therefore, the total content of Fe₂O₃, Al₂O₃, and CaO is preferably 1.0% by mass or more and 2.0% by mass or less.

[0091] In addition, talc containing a total content of Fe2O3 and Al2O3 exceeding 1.0% by mass is readily available. Furthermore, if the total content of Fe2O3 and Al2O3 in the talc is 2.0% by mass or less, the moldability of the liquid crystal resin composition and the heat resistance of the molded article obtained from the liquid crystal resin composition are less likely to deteriorate. Therefore, the total content of Fe2O3 and Al2O3 is preferably greater than 1.0% by mass and less than 1.7% by mass.

[0092] Furthermore, if the CaO content in the talc is less than 0.5% by mass, the moldability of the liquid crystal resin composition and the heat resistance of the molded article obtained from the liquid crystal resin composition are less likely to deteriorate. Therefore, the CaO content is preferably 0.01% by mass to 0.4% by mass.

[0093] Mica

[0094] Mica refers to a pulverized product of silicate minerals containing aluminum, potassium, magnesium, sodium, iron, etc. Examples of mica that can be used in the present invention include muscovite, phlogopite, biotite, and artificial mica. Among these, muscovite is preferred due to its good color tone and low price.

[0095] In addition, in the manufacture of mica, as methods for crushing minerals, there are known methods: wet crushing and dry crushing. The wet crushing method refers to the following method: after the mica ore is coarsely crushed in a dry crusher, water is added to the slurry state and the wet crushing is carried out to formally crush it, and then dehydrated and dried. Compared with the wet crushing method, the dry crushing method is a low-cost and common method, but if the wet crushing method is used, it is easier to crush the mineral thinly and finely. In order to obtain mica having the above-mentioned median particle size and the preferred thickness described below, it is preferred to use a thin and fine crushed product in the present invention. Therefore, in the present invention, it is preferred to use mica produced by the wet crushing method.

[0096] In addition, in the wet pulverization method, it is necessary to disperse the pulverized material in water. Therefore, in order to improve the dispersion efficiency of the pulverized material, a flocculating sedimentation agent and / or a sedimentation aid is usually added to the pulverized material. As flocculating sedimentation agents and sedimentation aids that can be used in the present invention, polyaluminum chloride, aluminum sulfate, ferrous sulfate, ferrous sulfate chloride, polyferric sulfate, polyferric chloride, iron-silicon dioxide inorganic polymer flocculants, ferric chloride-silicon dioxide inorganic polymer flocculants, slaked lime (Ca(OH)2), caustic soda (NaOH), sodium ash (Na2CO3), etc. can be mentioned. The pH of these flocculating sedimentation agents and sedimentation aids is alkaline or acidic. The mica used in the present invention is preferably not used with a flocculating sedimentation agent and / or a sedimentation aid when wet pulverization is performed. If mica that has not been treated with a flocculating sedimentation agent and / or sedimentation aid is used, decomposition of the polymer in the liquid crystalline resin composition is less likely to occur, and large amounts of gas generation and a decrease in the molecular weight of the polymer are less likely to occur. Therefore, the performance of the resulting molded product can be more easily maintained.

[0097] The thickness of the mica used in the present invention, as measured by electron microscopic observation, is preferably 0.01 to 1 μm, particularly preferably 0.03 to 0.3 μm. A mica thickness of 0.01 μm or greater is preferred because it is less likely to break during melt processing of the liquid crystalline resin composition, potentially improving the rigidity of the molded article. A mica thickness of 1 μm or less is preferred because it is more likely to achieve a sufficient improvement in the rigidity of the molded article.

[0098] The mica that can be used in the present invention may be surface-treated with a silane coupling agent or the like, and / or may be granulated with a binder to form particles.

[0099] [Other ingredients]

[0100] The liquid crystalline resin composition of the present invention may also contain other polymers, other fillers, other release agents, known substances commonly added to synthetic resins, such as antioxidants, stabilizers such as ultraviolet absorbers, antistatic agents, flame retardants, colorants such as dyes and pigments, lubricants, crystallization accelerators, crystallization nucleating agents, etc., as appropriate according to the required performance, within the scope that does not hinder the effects of the present invention.

[0101] Examples of other polymers include epoxy-containing styrene polymers and epoxy-free olefin polymers. Examples of epoxy-containing styrene polymers include known epoxy-containing styrene polymers, including copolymers composed of repeating units derived from styrenes and repeating units derived from glycidyl esters of α,β-unsaturated acids. Examples of epoxy-free olefin polymers include polyethylene, polypropylene, polybutene, ethylene-propylene copolymers, ethylene-butene copolymers, ethylene-octene copolymers, polybutadiene, polyisoprene, polychloroprene, ethylene-propylene-butadiene copolymers, ethylene-propylene-isoprene copolymers, ethylene-propylene-chloroprene copolymers, ethylene-ethyl acrylate copolymers, and ethylene-vinyl acetate copolymers.

[0102] Other fillers refer to fillers other than the (B) whiskers and the (E) plate-like fillers, and examples thereof include (C) particulate fillers such as silica; fibrous fillers other than the (B) whiskers such as glass fibers; and carbon black. The liquid crystalline resin composition of the present invention preferably does not contain fibrous fillers other than the (B) whiskers, such as glass fibers, because this tends to enhance the effect of suppressing fuzzing on the surface of the molded article.

[0103] Other release agents refer to release agents other than (D) polyol fatty acid esters, and examples thereof include fatty acid metal salts such as calcium stearate; fatty acid amides; and low-molecular-weight polyolefins. The liquid crystalline resin composition of the present invention preferably does not contain (D) release agents other than polyol fatty acid esters, such as fatty acid metal salts such as calcium stearate, in order to facilitate obtaining a molded article having improved blister resistance while maintaining superior mechanical strength and releasability.

[0104] [Preparation of Liquid Crystalline Resin Composition]

[0105] The preparation method of the resin composition of the present invention is not particularly limited. For example, the above-mentioned component (A), component (B), component (C), component (D), optional component (E), and optional other ingredients are mixed and melt-kneaded using a single-screw extruder or a twin-screw extruder to prepare the liquid crystalline resin composition.

[0106] [Liquid crystal resin composition]

[0107] The melt viscosity of the liquid crystalline resin composition of the present invention obtained as described above is preferably 100 Pa·sec or less, more preferably 90 Pa·sec or less, and even more preferably 85 Pa·sec or less, from the viewpoint of fluidity. The lower limit of the above-mentioned melt viscosity is not particularly limited, and may be 5 Pa·sec or more, 10 Pa·sec or more, or 20 Pa·sec or more. High fluidity and excellent formability during melting are also characteristics of the liquid crystalline resin composition of the present invention. In this specification, the melt viscosity is defined as: a barrel temperature 10 to 30°C higher than the melting point of the liquid crystalline resin, a shear rate of 1000 sec -1 The value obtained by the measurement method based on ISO 11443 under conditions of .

[0108] <Connector>

[0109] The liquid crystalline resin composition can be used in a connector. More specifically, the liquid crystalline resin composition can be used to manufacture a connector. That is, the liquid crystalline resin composition can be used to manufacture a connector. The connector of the present invention comprises a molded body containing the liquid crystalline resin composition of the present invention. The molded body containing the liquid crystalline resin composition of the present invention has excellent mechanical strength and demolding properties, and the occurrence of blistering is suppressed. Therefore, it can be suitable for use as a high-performance connector with excellent blister resistance. It should be noted that the molded body can be obtained by molding the liquid crystalline resin composition of the present invention. The molding method is not particularly limited, and injection molding can be mentioned as an example.

[0110] Examples of the connector include a planar connector (CPU socket, LGA socket), an FPC connector, a strip connector, a board-to-board (B to B) connector, a memory card connector, and a memory module connector.

[0111] A planar connector is a planar connector having a grid structure inside an outer frame of a CPU socket or the like. As the miniaturization of electronic components is progressing, the thinning and narrowing of planar connectors are also progressing accordingly. In a planar connector with a very thin-walled grid portion, if you want to fill the grid portion with resin, the fluidity is not sufficient, so the filling pressure becomes high, and as a result, there are problems such as the amount of warping deformation of the obtained planar connector becoming more. According to the connector of the present invention, low warping is improved, and in addition, bending characteristics and the like are also improved, and the fluidity of the resin composition used is also high. Therefore, even if the minimum wall thickness of the resin portion for holding the terminal is less than 0.3 mm and the pitch of the grid portion is less than 1.5 mm, warping is not easy to occur, and a connector with high toughness can be obtained. In addition, the fluidity of the resin composition of the present invention is also high, so even if it is a thin-walled, narrow-pitch planar connector, it can be easily molded.

[0112] The FPC connector connected to the FPC substrate is usually arranged at a constant pitch. With the demand for miniaturization of equipment in recent years, the arrangement pitch of the connection part needs to be further narrowed. However, in order to be molded into a connector with a narrow pitch, the fluidity of the resin composition is required. In addition, in order to be actually used as a connector, the connector is required to have less warping and a certain level of toughness and mechanical strength. The connector of the present invention has high bending properties such as toughness and low warping according to the properties of the resin composition used. The fluidity of the resin composition is also high. Therefore, it can also be used for FPC connectors that have been promoted to narrow pitch. Here, "narrow pitch" means that the spacing between the connection parts is less than 1 mm. The connector of the present invention can also be preferably used for small connectors with a pitch of less than 1 mm and a wall thickness of less than 0.2 mm between terminals.

[0113] A strip connector is one with multiple connecting sections along its length. This type of connector is also being developed with narrower pitches and thinner profiles. The connector of the present invention can be fully applied even if the inter-terminal pitch is less than 1.5 mm and the inter-terminal wall thickness is less than 0.3 mm.

[0114] A board-to-board (B-to-B) connector is used to connect printed wiring boards. As electronic devices using printed wiring boards become smaller, the mounting area for the connector is required to be smaller. Furthermore, to reduce the distance between two printed wiring boards, thinner connectors are also required. The connector of the present invention can be suitably used even if its minimum wall thickness is 0.3 mm or less and the pitch between the connector terminals is 1.5 mm or less.

[0115] The method for obtaining the connector is not particularly limited, and a conventionally known method can be used, but injection molding is preferred. Specific embodiments

[0117] The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these examples.

[0118] Liquid crystal resin

[0119] Aromatic polyester amide

[0120] After the following raw materials are added to the polymerization vessel, the temperature of the reaction system is raised to 140°C and the reaction is carried out at 140°C for 1 hour. After that, the temperature is further raised to 340°C over 4.5 hours, and the pressure is reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes, while acetic acid, excess acetic anhydride and other low-boiling components are distilled off and melt polymerization is carried out. After the stirring torque reaches the specified value, nitrogen is introduced, and a pressurized state is formed from the reduced pressure state to the normal pressure state. The polymer is discharged from the bottom of the polymerization vessel, and the strands are granulated to obtain pellets. The obtained pellets are heat-treated at 300°C for 2 hours under a nitrogen flow to obtain the target polymer. The melting point of the obtained polymer is 336°C, and the melt viscosity at 350°C is 19.0 Pa·s. It should be noted that the melt viscosity of the above-mentioned polymer is measured in the same manner as the melt viscosity measurement method described below.

[0121] 4-Hydroxybenzoic acid (HBA): 1380 g (60 mol%)

[0122] 6-Hydroxy-2-naphthoic acid (HNA): 157 g (5 mol%)

[0123] 1,4-Benzenedicarboxylic acid (TA): 484 g (17.5 mol%)

[0124] 4,4'-dihydroxybiphenyl (BP): 388 g (12.5 mol%)

[0125] N-acetyl-p-aminophenol (APAP): 126 g (5 mol%)

[0126] Metal catalyst (potassium acetate catalyst): 110 mg

[0127] Acylating agent (acetic anhydride): 1659g

[0128] Aromatic polyester

[0129] After the following raw materials are added to the polymerization vessel, the temperature of the reaction system is raised to 140°C and the reaction is carried out at 140°C for 1 hour. After that, the temperature is further raised to 360°C over 5.5 hours, and the pressure is reduced to 5 Torr (i.e., 667 Pa) over 20 minutes, while acetic acid, excess acetic anhydride, and other low-boiling fractions are distilled off and melt polymerization is carried out. After the stirring torque reaches the specified value, nitrogen is introduced, and a pressurized state is formed from the reduced pressure state to the normal pressure state. The polymer is discharged from the bottom of the polymerization vessel, and the strands are granulated to form pellets to obtain the target polymer. The melting point of the obtained polymer is 355°C and the melt viscosity is 10 Pa·s. It should be noted that the melt viscosity of the above-mentioned polymer is measured in the same manner as the melt viscosity measurement method described below.

[0130] 4-Hydroxybenzoic acid (HBA): 1040 g (48 mol%)

[0131] 6-Hydroxy-2-naphthoic acid (HNA): 89 g (3 mol%)

[0132] 1,4-Benzenedicarboxylic acid (TA): 547 g (21 mol%)

[0133] 1,3-Benzenedicarboxylic acid (IA): 91 g (3.5 mol%)

[0134] 4,4'-dihydroxybiphenyl (BP): 716 g (24.5 mol%)

[0135] Potassium acetate catalyst: 110 mg

[0136] Acetic anhydride: 1644g

[0137] [Method for measuring melting point]

[0138] Using a DSC manufactured by TA Instruments, the endothermic peak temperature (Tm1) observed when the liquid crystalline resin is heated from room temperature at a heating rate of 20°C / minute is measured. The liquid crystalline resin is then maintained at a temperature of (Tm1+40)°C for 2 minutes, and then temporarily cooled to room temperature at a cooling rate of 20°C / minute. The endothermic peak temperature (Tm2) observed when the liquid crystalline resin is heated again at a heating rate of 20°C / minute is measured as the melting point of the polymer.

[0139] <Materials other than liquid crystal resins>

[0140] Wollastonite: WOLLASTONITE SH-1250BJ (manufactured by KINSEI MATEC CO., LTD., calcium silicate whiskers (wollastonite), average fiber length 130 μm, fiber diameter 8 μm)

[0141] Potassium titanate: TISMO N-102 (manufactured by Otsuka Chemical Co., Ltd., potassium titanate whiskers (potassium titanate fibers), fiber diameter 0.3-0.6 μm, average fiber length 10-20 μm)

[0142] Mica: AB-25S (manufactured by Yamagucci Mica Co., Ltd., mica, median particle size 25.0 μm)

[0143] Ethylene-glycidyl methacrylate copolymer: Bondfast BF-2C (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate copolymer, glycidyl methacrylate content 6% by mass)

[0144] Pentaerythritol tetrastearate: Unister H-476 (manufactured by NOF Corporation, pentaerythritol tetrastearate)

[0145] ·Calcium stearate: Calcium stearate GF-200 (manufactured by NOF Co., Ltd., calcium stearate)

[0146] <Production of Liquid Crystal Resin Composition>

[0147] The above components were melt-kneaded at the ratios (mass %) shown in Table 1 or Table 2 using a twin-screw extruder (TEX30α, manufactured by The Nippon Steel Works, Ltd.) at the following barrel temperature to obtain liquid crystal resin composition pellets.

[0148] 〔Manufacturing conditions〕

[0149] Barrel temperature:

[0150] 350°C: In the case of a liquid crystal resin composition containing the above aromatic polyester amide

[0151] 370°C: In the case of a liquid crystal resin composition containing the above aromatic polyester

[0152] Melt viscosity

[0153] The melt viscosity of the liquid crystalline resin composition was measured using a capillary rheometer model 1B manufactured by Toyo Seiki Seisaku-sho, Ltd., at a temperature 10-30°C higher than the melting point of the liquid crystalline resin, using an orifice with an inner diameter of 1 mm and a length of 20 mm, at a shear rate of 1000 / s, in accordance with ISO 11443. The specific measurement temperature was 350°C for the liquid crystalline resin composition containing the aromatic polyester amide, and 370°C for the liquid crystalline resin composition containing the aromatic polyester. The results are shown in Tables 1 and 2.

[0154] <Bending test>

[0155] The pellets of Examples and Comparative Examples were molded using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries, Ltd.) under the following molding conditions to produce ISO Type A test pieces. These test pieces were cut to obtain measurement test pieces (80 mm × 10 mm × 4 mm). Using these measurement test pieces, flexural strength, flexural modulus, and flexural strain were measured in accordance with ISO 178. The results are shown in Tables 1 and 2.

[0156] [Molding conditions]

[0157] Barrel temperature:

[0158] 350°C (Examples 1 to 3 and 7 to 10 and Comparative Examples 1 and 3 to 9)

[0159] 370°C (Examples 4 to 6 and Comparative Example 2)

[0160] Mold temperature: 90℃

[0161] Injection speed: 33mm / s

[0162] <Deflection Temperature under Load>

[0163] The liquid crystal resin composition was injection molded under the following molding conditions to produce an ISO test piece type A. This test piece was cut into 80 mm × 10 mm × 4 mm pieces to prepare test pieces. Using these test pieces, the load deflection temperature was measured in accordance with ISO 75-1 and 2. The load deflection temperature is used as an indicator of the heat resistance of the molded article. The results are shown in Tables 1 and 2.

[0164] [Molding conditions]

[0165] Molding machine: SE100DU, manufactured by Sumitomo Heavy Industries, Ltd.

[0166] Barrel temperature:

[0167] 350°C (Examples 1 to 3 and 7 to 10 and Comparative Examples 1 and 3 to 9)

[0168] 370°C (Examples 4 to 6 and Comparative Example 2)

[0169] Mold temperature: 90℃

[0170] Injection speed: 33mm / s

[0171] <Foaming temperature>

[0172] Using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries, Ltd.), the pellets of the examples and comparative examples were molded under the following molding conditions to obtain a molded product of 12.5 mm × 120 mm × 0.8 mm having a welded portion. The molded product was divided into two at the welded portion, and the obtained fragment was used as a test body and clamped on a hot plate at a specified temperature for 5 minutes. Afterwards, it was visually inspected whether bubbles were generated on the surface of the test body. The bubble temperature was set to the highest temperature at which the number of bubbles generated became zero. It should be noted that the specified temperature was set at intervals of 10°C within the range of 200 to 300°C. The results are shown in Tables 1 and 2.

[0173] [Molding conditions]

[0174] Barrel temperature:

[0175] 350°C (Examples 1 to 3 and 7 to 10 and Comparative Examples 1 and 3 to 9)

[0176] 370°C (Examples 4 to 6 and Comparative Example 2)

[0177] Mold temperature: 90℃

[0178] Injection speed: 33mm / s

[0179] <Evaluation of mold release properties>

[0180] The liquid crystal resin composition was injection molded under the following molding conditions to produce Figure 1 (a) and Figure 1 The U-shaped liquid crystal resin molded article (thickness: 0.5 mm) shown in (b) was evaluated for releasability according to the following criteria. The results are shown in Tables 1 and 2.

[0181] ○ (good): No defect occurred in which the molded article adhered to the mold and could not be released from the mold.

[0182] × (poor): The defect that the molded article adhered to the mold and could not be released from the mold occurred once or more.

[0183] [Molding conditions]

[0184] Molding machine: Sumitomo Heavy Industries, Ltd., SE30DUZ

[0185] Barrel temperature:

[0186] 350°C (Examples 1 to 3 and 7 to 10 and Comparative Examples 1 and 3 to 9)

[0187] 370°C (Examples 4 to 6 and Comparative Example 2)

[0188] Mold temperature: 90℃

[0189] Injection speed: 100 mm / s Number of injections: 100 injections [Table 1]

[0190]

[0191] [Table 2]

[0192]

[0193] From the results described in Tables 1 and 2, it was clearly confirmed that the molded articles formed from the liquid crystalline resin compositions of Examples were excellent in mechanical strength and releasability, and that the occurrence of bubbles was suppressed.

Claims

1. A liquid crystal resin composition comprising: (A) liquid crystal resin, (B) Whiskers, (C) an epoxy group-containing olefin polymer, and (D) polyol fatty acid esters, With respect to the entire liquid crystal resin composition, The content of the whiskers (B) is 20-40% by mass. The content of the epoxy group-containing olefin polymer (C) is 0.5 to 6% by mass. The content of the (D) polyol fatty acid ester is 0.1 to 2.0% by mass.

2. The liquid crystalline resin composition according to claim 1, wherein The (A) liquid crystalline resin is an aromatic polyester or aromatic polyester amide having, as a constituent component, a structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

3. The liquid crystalline resin composition according to claim 1 or 2, wherein The (D) polyol fatty acid ester is at least one selected from the group consisting of fatty acid esters of pentaerythritol and fatty acid esters of dipentaerythritol.

4. The liquid crystalline resin composition according to claim 1 or 2, wherein The content of the (B) whiskers is 25 to 40% by mass based on the entire liquid crystalline resin composition.

5. The liquid crystalline resin composition according to claim 1 or 2, further comprising (E) a plate-like filler, The content of the (E) plate-like filler is 5 to 15% by mass based on the entire liquid crystalline resin composition. The liquid crystalline resin composition according to claim 1 or 2, which is used for a connector.

7. Use of the liquid crystalline resin composition according to claim 1 or 2 in the manufacture of a connector. A molded body comprising the liquid crystalline resin composition according to claim 1 or 2.

9. A connector comprising the molded article according to claim 8.

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