Liquid crystalline resin composition and camera module using same

Abstract

Provided are a liquid crystalline resin composition which has good fluidity, and from which a molded body that is excellent in terms of low-dust generation properties, low slide wear properties, low warping properties, and suppression of inward collapse deformation in a well-balanced manner is obtained, and a camera module using the same.　A liquid crystalline resin composition according to the present invention contains (A) a liquid crystalline resin, (B) a granular filler, (C) a plate-shaped filler, and (D) an olefin-based polymer, wherein: the median diameter of the component (B) is 0.3 µm to 8 µm; the median diameter of the component (C) is 10 μm to 50 μm; the component (D) includes an epoxy group-containing olefin-based polymer; and with respect to the entire liquid crystalline resin composition, the content of the component (A) is 52% by mass to 82% by mass, the content of the component (B) is 2.5% by mass to 35% by mass, the content of the component (C) is 5% by mass to 35% by mass, the total content of the component (B) and the component (C) is 15% by mass to 45% by mass, the content of the component (D) is 1.50% by mass to 6.00% by mass, and the content of the epoxy group is 0.003% by mass to 0.050% by mass.

Description

Liquid crystal resin composition and camera module using the same

[0001] The present invention relates to a liquid crystalline resin composition and a camera module using the same.

[0002] Liquid crystalline resins are widely used as high-performance engineering plastics because they have a good balance of excellent mechanical strength, heat resistance, chemical resistance, electrical properties, etc., as well as excellent dimensional stability. Recently, liquid crystalline resins have been used in precision equipment parts, taking advantage of these characteristics.

[0003] Examples of parts that use liquid crystalline resins include connectors such as FPC connectors; sockets such as memory card sockets; camera module parts such as lens holders; and relays. These parts are required to have low warpage, mechanical strength, and low dust generation. Furthermore, since they may be used in a configuration in which two or more components are in dynamic contact, they are also required to have reduced sliding wear (i.e., the tendency for wear when two or more components are in dynamic contact). For example, Patent Document 1 discloses a liquid crystalline resin composition containing a liquid crystalline resin and talc having a specific volume average particle size in a specific ratio, with the objective of providing a molded article made from a liquid crystalline resin composition that has excellent surface appearance and excellent sliding properties.

[0004] Patent No. 5087958

[0005] If the dimensional accuracy of the above-mentioned parts is not ensured, they may not function properly. Therefore, the above-mentioned parts are required to have excellent low warpage properties and suppress inward collapse deformation so as to ensure the dimensional accuracy. Furthermore, when a molded product is obtained by molding a liquid crystalline resin composition, the liquid crystalline resin composition is required to have good fluidity.

[0006] However, according to the investigations of the present inventors, conventional liquid crystalline resin compositions have insufficient fluidity, or molded articles containing such liquid crystalline resin compositions have room for improvement in terms of low dust generation, low sliding wear, low warpage, or suppression of inward collapse deformation.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a liquid crystalline resin composition having good fluidity that gives a molded article having a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation, and a camera module using the same.

[0008] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that the above-mentioned problems can be solved by using a liquid crystalline resin composition containing a liquid crystalline resin, a predetermined granular filler, a predetermined plate-like filler, and an olefin polymer in specific ratios, wherein the olefin polymer includes an epoxy group-containing olefin polymer, and the epoxy group content is within a predetermined range. This finding led to the completion of the present invention. More specifically, the present invention provides the following.

[0009] (1) A liquid crystalline resin composition comprising (A) a liquid crystalline resin, (B) a granular filler, (C) a plate-like filler, and (D) an olefin-based polymer, wherein the (B) granular filler has a median diameter of 0.3 to 8 μm, the (C) plate-like filler has a median diameter of 10 to 50 μm, and the (D) olefin-based polymer comprises an epoxy group-containing olefin-based polymer, and the liquid crystalline resin composition has a total content of the (A) liquid crystalline resin of 52 to 82% by mass, the (B) granular filler of 2.5 to 35% by mass, the (C) plate-like filler of 5 to 35% by mass, the total content of the (B) granular filler and the (C) plate-like filler of 15 to 45% by mass, and the (D) olefin-based polymer of 1.50 to 6.00% by mass. The liquid crystal resin composition has an epoxy group content of 0.003 to 0.050% by mass.

[0010] (2) The liquid crystalline resin composition according to (1), wherein the (A) liquid crystalline resin is an aromatic polyester or an aromatic polyester amide having, as a constituent component, a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

[0011] (3) The liquid crystal resin composition according to (1) or (2), wherein the granular filler (B) comprises one or more selected from the group consisting of silica and barium sulfate, and the plate-like filler (C) comprises one or more selected from the group consisting of talc and mica.

[0012] (4) The liquid crystalline resin composition according to any one of (1) to (3), which is used for a camera module component.

[0013] (5) Use of the liquid crystal resin composition according to any one of (1) to (4) for producing a camera module component.

[0014] (6) A molded article comprising the liquid crystal resin composition according to any one of (1) to (4).

[0015] (7) A camera module component made of the molded article according to (6).

[0016] (8) A camera module including the camera module component according to (7).

[0017] According to the present invention, it is possible to provide a liquid crystalline resin composition having good fluidity that gives a molded article having a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation, and a camera module using the same.

[0018] FIG. 1 is a cross-sectional view schematically showing a typical camera module. FIG. 2 is a diagram illustrating a method for evaluating low sliding wear. FIG. 3(a) is a diagram showing a camera module molded article used in a warpage evaluation, and FIG. 3(b) is a diagram showing measurement points in the warpage evaluation. The units of values ​​in the diagram are mm. FIG. 4(a) is a perspective view showing a U-shaped liquid crystalline resin molded article used in an inward collapse evaluation performed in the examples, and FIG. 4(b) is a side view showing the U-shaped liquid crystalline resin molded article.

[0019] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0020] <Liquid Crystalline Resin Composition for Camera Module> The liquid crystal resin composition for a camera module of the present invention contains (A) a liquid crystal resin, (B) a granular filler, (C) a plate-like filler, and (D) an olefin polymer.

[0021] [(A) Liquid Crystalline Resin] The (A) liquid crystal resin used in the present invention refers to a melt-processable polymer capable of forming an optically anisotropic molten phase. The properties of the anisotropic molten phase can be confirmed by a conventional polarization examination method using crossed polarizers. More specifically, the anisotropic molten phase can be confirmed by observing a molten sample placed on a Leitz hot stage at 40x magnification using a Leitz polarizing microscope under a nitrogen atmosphere. When examined between crossed polarizers, the liquid crystal polymer applicable to the present invention normally transmits polarized light, even in a molten, stationary state, and exhibits optical anisotropy.

[0022] The type of the liquid crystalline resin (A) described above is not particularly limited, but is preferably an aromatic polyester and / or an aromatic polyester amide. Polyesters partially containing aromatic polyesters and / or aromatic polyester amides in the same molecular chain are also included. The liquid crystalline resin (A) preferably has an inherent viscosity (I.V.) of at least about 2.0 dl / g, more preferably 2.0 to 10.0 dl / g, when dissolved in pentafluorophenol at 60°C to a concentration of 0.1% by mass.

[0023] The aromatic polyester or aromatic polyesteramide as the liquid crystal resin (A) applicable to the present invention is particularly preferably an aromatic polyester or aromatic polyesteramide having, as a constituent component, a constituent unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof.

[0024] More specifically, (1) polyesters mainly composed of structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof; (2) polyesters mainly composed of (a) structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and derivatives thereof, and (b) structural units derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof; (3) polyesters 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 dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof, and (c) structural units derived from at least one selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols, and derivatives thereof; (4) polyesteramides mainly consisting of (a) structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives, (b) structural units derived from at least one selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and their derivatives, and (c) structural units derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives; (5) polyesteramides mainly consisting of (a) structural units derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives, (b) structural units derived from at least one selected from the group consisting of aromatic hydroxyamines, aromatic diamines, and their derivatives, (c) structural units derived from at least one selected from the group consisting of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and their derivatives, and (d) structural units derived from at least one selected from the group consisting of aromatic diols, alicyclic diols, aliphatic diols, and their derivatives. Furthermore, a molecular weight modifier may be used in combination with the above structural components as needed.

[0025] In the (A) liquid crystalline resin, the content of the structural unit derived from at least one selected from the group consisting of aromatic hydroxycarboxylic acids and their derivatives is preferably 45 mol% or more, more preferably 50 mol% or more, even more preferably 55 mol% or more, even more preferably 60 mol% or more, and particularly preferably 62 mol% or more, based on all structural units, from the viewpoint of suppressing fluctuations in the molecular structure of the (A) liquid crystalline resin. The upper limit of the 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, based on all structural units.

[0026] Preferred examples of the compound constituting the (A) liquid crystal resin applicable to 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-phenylenedicarboxylic acid, 1,3-phenylenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid and compounds represented by the following general formula (III); and aromatic amines such as p-aminophenol, p-phenylenediamine and N-acetyl-p-aminophenol. As the aromatic hydroxycarboxylic acid and its 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 (A) liquid crystal resin. (X: alkylene (C １ ~C ４ ), alkylidene, —O—, —SO—, —SO ２ is a group selected from —, —S—, and —CO—. (Y:-(CH ２ ) ｎ -(n=1 to 4) and -O(CH ２ ) ｎ O- (n = 1 to 4).

[0027] The liquid crystal resin (A) used in the present invention can be prepared by known methods such as direct polymerization or transesterification from the above-mentioned monomer compound (or mixture of monomers). Typically, melt polymerization, solution polymerization, slurry polymerization, solid-state polymerization, or a combination of two or more of these methods is used. Melt polymerization or a combination of melt polymerization and solid-state polymerization is preferred. The above-mentioned compounds capable of forming esters may be used in the polymerization in their original form, or may be modified from a precursor to a derivative capable of forming an ester prior to polymerization. Various catalysts can be used in these polymerizations. Representative examples include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and tris(2,4-pentanedionato)cobalt(III), and organic compound catalysts such as 1-methylimidazole and 4-dimethylaminopyridine. The amount of catalyst used is generally about 0.001 to 1% by mass, and preferably about 0.01 to 0.2% by mass, based on the total mass of the monomers. If necessary, the polymers produced by these polymerization methods can be further subjected to solid-phase polymerization in which they are heated under reduced pressure or in an inert gas to increase the molecular weight.

[0028] The melt viscosity of the liquid crystalline resin (A) obtained by the above method is not particularly limited. Generally, the melt viscosity at the molding temperature is －１ A liquid crystal resin having a viscosity of 3 Pa·s or more and 500 Pa·s or less can be used. However, a liquid crystal resin having a viscosity that is too high is not preferred because it will have a significantly reduced fluidity. The liquid crystal resin (A) may be a mixture of two or more liquid crystal resins.

[0029] 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 82 mass%, more preferably 53 to 75 mass%, and even more preferably 54 to 70 mass%. The content of the component (A) within the above range is preferred in terms of flowability, heat resistance, etc.

[0030] [(B) Granular Filler] The liquid crystalline resin composition according to the present invention contains (B) a granular filler. The median diameter of (B) the granular filler is 0.3 to 8.0 μm. When the median diameter is 0.3 μm or more, the mechanical strength of the molded article is likely to be maintained. When the median diameter is 8.0 μm or less, the liquid crystalline resin composition is likely to have good fluidity. The median diameter is preferably 0.4 to 7.5 μm, and more preferably 0.5 to 7.0 μm. In this specification, the median diameter of (B) the granular filler refers to the volume-based median value measured by a laser diffraction / scattering particle size distribution measurement method. The median diameter can be measured, for example, using a laser diffraction / scattering particle size distribution measurement device LA-920 manufactured by Horiba, Ltd. The median diameter of the granular filler (B) in the liquid crystalline resin composition is measured by the above-mentioned method for the granular filler (B) remaining after heating the liquid crystalline resin composition for 2 hours at 600° C. The granular filler (B) may be used singly or in combination of two or more kinds.

[0031] Examples of the granular filler (B) include metal oxides such as silica, quartz powder, glass beads, glass powder, potassium aluminum silicate, diatomaceous earth, iron oxide, titanium oxide, zinc oxide, and alumina; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; phosphates such as calcium pyrophosphate and anhydrous dicalcium phosphate; silicon carbide; silicon nitride; boron nitride, etc. In the present invention, from the viewpoint of suppressing inward collapse deformation of the molded body, it is preferable to use one or more selected from the group consisting of silica and barium sulfate as the granular filler (B), and it is more preferable to use silica.

[0032] The content of the (B) component is 2.5 to 35% by mass relative to the total liquid crystal composition of the present invention. When the content of the (B) component is 2.5% by mass or more, the molded article is likely to be prevented from inward collapse deformation. When the content of the (B) component is 35% by mass or less, the liquid crystal resin composition is likely to have good fluidity. The content of the (B) component is preferably 4 to 25% by mass, more preferably 5 to 21% by mass.

[0033] [(C) Plate-like filler] The liquid crystalline resin composition according to the present invention contains (C) a plate-like filler. When the liquid crystalline resin composition according to the present invention contains (C) a plate-like filler, the low dust generation and low warpage properties of the molded article are likely to be improved. The (C) plate-like filler can be used alone or in combination of two or more.

[0034] The median diameter of the plate-like filler (C) is 10 to 50 μm. When the median diameter is within the above range, the liquid crystalline resin composition tends to have good fluidity, and a molded article containing the liquid crystalline resin composition tends to maintain low warpage. The median diameter is preferably 11 to 40 μm, more preferably 12 to 30 μm. In this specification, the median diameter of the plate-like filler (C) refers to the volume-based median value measured by a laser diffraction / scattering particle size distribution measurement method. The median diameter can be measured, for example, using a laser diffraction / scattering particle size distribution measurement device LA-920 manufactured by Horiba, Ltd. The median diameter of the plate-like filler (C) in the liquid crystalline resin composition is measured by applying the above method to the plate-like filler (C) remaining after heating the liquid crystalline resin composition to incinerate it at 600°C for 2 hours.

[0035] Examples of the plate-like filler (C) in the present invention include talc, mica, glass flakes, various metal foils, etc. From the viewpoint of suppressing the anisotropy of a molded article obtained from the liquid crystalline resin composition without deteriorating the fluidity of the liquid crystalline resin composition, one or more selected from the group consisting of talc and mica are preferred, and mica is more preferred.

[0036] [Talc] The talc that can be used in the present invention is a talc containing Fe, ２ O ３ , Al ２ O ３ and CaO total content is 2.5 mass% or less, and Fe ２ O ３ and Al ２ O ３ The total content of these is preferably more than 1.0 mass % and not more than 2.0 mass %, and the CaO content is less than 0.5 mass %. That is, the talc that can be used in the present invention is preferably one in which the main component, SiO ２and MgO, as well as Fe ２ O ３ , Al ２ O ３ and CaO, each of which may be contained within the above-mentioned content ranges.

[0037] In the above talc, Fe ２ O ３ , Al ２ O ３ When the total content of Fe and CaO is 2.5% by mass or less, the moldability of the liquid crystal resin composition and the heat resistance of a molded article formed from the liquid crystal resin composition are unlikely to deteriorate. ２ O ３ , Al ２ O ３ The total content of Si and CaO is preferably 1.0 mass % or more and 2.0 mass % or less.

[0038] Among the above talc, Fe ２ O ３ and Al ２ O ３ Talc having a total content of more than 1.0 mass % is readily available. ２ O ３ and Al ２ O ３ When the total content of Fe is 2.0 mass % or less, the moldability of the liquid crystal resin composition and the heat resistance of the molded article molded from the liquid crystal resin composition are unlikely to deteriorate. ２ O ３ and Al ２ O ３ The total content of is preferably more than 1.0 mass % and 1.7 mass % or less.

[0039] Furthermore, when 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 a molded article formed from the liquid crystal resin composition are unlikely to deteriorate, and therefore the CaO content is preferably 0.01% by mass or more and 0.4% by mass or less.

[0040] [Mica] Mica is a pulverized silicate mineral 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, with muscovite being preferred among these because of its good hue and low cost.

[0041] In addition, wet grinding and dry grinding are known as methods for grinding minerals in the production of mica. The wet grinding method involves roughly grinding mica raw ore in a dry grinder, adding water to form a slurry, wet grinding the resulting material, and then dehydrating and drying. Compared to the wet grinding method, the dry grinding method is a more common method with lower costs, but the wet grinding method makes it easier to grind minerals thinly and finely. It is preferable to use thin, finely ground material in the present invention because it allows the production of mica having the above-mentioned median diameter and the preferred thickness described below. Therefore, it is preferable to use mica produced by the wet grinding method in the present invention.

[0042] In addition, since the wet grinding method requires a step of dispersing the material to be ground in water, it is common to add a flocculating sedimentation agent and / or a sedimentation aid to the material to be ground in order to improve the dispersion efficiency of the material. Examples of flocculating sedimentation agents and sedimentation aids that can be used in the present invention include polyaluminum chloride, aluminum sulfate, ferrous sulfate, ferric sulfate, copper chloride, polyiron sulfate, polyferric chloride, iron-silica inorganic polymer flocculant, ferric chloride-silica inorganic polymer flocculant, slaked lime (Ca(OH) ２ ), caustic soda (NaOH), soda ash (Na ２ CO ３ ) and the like. These flocculating sedimentation agents and sedimentation aids have an alkaline or acidic pH. The mica used in the present invention is preferably one that has not been treated with a flocculating sedimentation agent and / or sedimentation aid during wet grinding. When 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 unlikely to occur, and large amounts of gas generation and a decrease in the molecular weight of the polymer are unlikely to occur, making it easier to maintain the performance of the resulting molded product better.

[0043] The thickness of the mica that can be used in the present invention is preferably 0.01 to 1 μm, particularly preferably 0.03 to 0.3 μm, as measured by observation with an electron microscope. If the thickness of the mica is 0.01 μm or more, the mica is less likely to crack during melt processing of the liquid crystalline resin composition, which is preferable because the rigidity of the molded article may be easily improved. If the thickness of the mica is 1 μm or less, the effect of improving the rigidity of the molded article is likely to be sufficient, which is preferable.

[0044] 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 granules.

[0045] The content of the component (C) is 5 to 35% by mass, preferably 8 to 25% by mass, and more preferably 10 to 21% by mass, based on the total mass of the liquid crystal resin composition of the present invention. When the content of the component (C) is within the above range, a molded article containing the liquid crystal resin composition tends to maintain low dust generation and low warpage.

[0046] The total content of the granular filler (B) and the plate-like filler (C) is 15 to 45% by mass, preferably 20 to 43% by mass, and more preferably 25 to 41% by mass, based on the total mass of the liquid crystal resin composition. When the total content is within the above range, a molded article containing the liquid crystal resin composition tends to have a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation.

[0047] [(D) Olefin-based polymer]

[0048] The liquid crystal resin composition of the present invention contains (D) an olefin polymer. The (D) olefin polymer may be used alone or in combination of two or more. The (D) olefin polymer is not particularly limited as long as it contains an epoxy group-containing olefin polymer, and may be an epoxy group-containing olefin polymer alone or a combination of an epoxy group-containing olefin polymer and an epoxy group-free olefin polymer. The (D) olefin polymer contributes to the liquid crystal resin composition of the present invention having good fluidity and to the molded article containing the liquid crystal resin composition of the present invention having a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation.

[0049] (Epoxy Group-Containing Olefin Polymer) Examples of the epoxy group-containing olefin polymer include copolymers composed of repeating units derived from an α-olefin and repeating units derived from a glycidyl ester of an α,β-unsaturated acid. The epoxy group-containing olefin polymers may be used alone or in combination of two or more.

[0050] The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, and butene, with ethylene being preferred. 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 represents a group represented by —COOH, and 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 itaconic acid, with glycidyl methacrylate being particularly preferred.

[0051] In the epoxy group-containing olefin polymer, the content of repeating units derived from an α-olefin is preferably 87 to 98% by mass, and the content of repeating units derived from a glycidyl ester of an α,β-unsaturated acid is preferably 13 to 2% by mass.

[0052] The epoxy group-containing olefin polymer may contain, in addition to the above two components, as a third component, 0 to 48 parts by mass of repeating units derived from one or more olefin-based unsaturated monomers such as acrylonitrile, acrylic acid esters, methacrylic acid esters, α-methylstyrene, and maleic anhydride, relative to 100 parts by mass of the above two components, within the scope of the present invention.

[0053] The epoxy group-containing olefin polymer can be easily prepared by a conventional radical polymerization method using monomers corresponding to the respective components and a radical polymerization catalyst. More specifically, it can usually be produced by copolymerizing an α-olefin and a glycidyl ester of an α,β-unsaturated acid in the presence of a radical generator at 500 to 4000 atmospheres and 100 to 300°C in the presence or absence of a suitable solvent or chain transfer agent. Alternatively, it can be produced by mixing an α-olefin, a glycidyl ester of an α,β-unsaturated acid, and a radical generator and melt-graft-copolymerizing the mixture in an extruder.

[0054] (Epoxy Group-Non-Containing Olefin Polymer) Examples of the epoxy group-non-containing olefin polymer include polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-octene copolymer, polybutadiene, polyisoprene, polychloroprene, ethylene-propylene-butadiene copolymer, ethylene-propylene-isoprene copolymer, ethylene-propylene-chloroprene copolymer, ethylene-ethyl acrylate copolymer, and ethylene-vinyl acetate copolymer, and polyethylene is preferred from the viewpoints of the fluidity of the liquid crystal resin composition and the mechanical strength of the molded product.

[0055] Examples of polyethylene include high-density polyethylene, low-density polyethylene, very-low-density polyethylene, linear low-density polyethylene, and ultra-high-molecular-weight polyethylene, and low-density polyethylene is preferred from the viewpoint of the fluidity of the liquid crystal resin composition and the mechanical strength of the molded product.

[0056] The epoxy group-free olefin polymer may contain repeating units derived from one or more olefin-based unsaturated monomers such as acrylonitrile, acrylic acid esters, methacrylic acid esters, α-methylstyrene, maleic anhydride, etc., within the scope of the present invention. The epoxy group-free olefin polymer may be used alone or in combination of two or more.

[0057] The content of the (D) olefin polymer is 1.50 to 6.00% by mass, preferably 2.00 to 6.00% by mass, and more preferably 3.00 to 6.00% by mass, based on the total mass of the liquid crystal resin composition of the present invention. When the content of the (D) component is within the above range, the liquid crystal resin composition tends to have good fluidity, and a molded article containing this liquid crystal resin composition tends to have a well-balanced excellent property of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation. The upper limit of the content of the (D) component may be 5.50% by mass or 5.00% by mass, and the content of the (D) component may be 1.50 to 5.50% by mass, 2.00 to 5.50% by mass, 3.00 to 5.50% by mass, 1.50 to 5.00% by mass, 2.00 to 5.00% by mass, or 3.00 to 5.00% by mass.

[0058] In the liquid crystalline resin composition, the content of the epoxy group is 0.003 to 0.050 mass %, preferably 0.010 to 0.048 mass %, and more preferably 0.018 to 0.045 mass %, based on the total mass of the liquid crystalline resin composition. When the content of the epoxy group is within the above range, the liquid crystalline resin composition tends to have good flowability, and a molded article containing this liquid crystalline resin composition tends to have a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation.

[0059] The content of the olefin polymer (C) and the content of the epoxy group in the liquid crystal resin composition can be adjusted to a desired range by appropriately increasing or decreasing the content of the epoxy group in the olefin polymer (C), the content of the epoxy group-containing olefin polymer, and the content of the epoxy group-free olefin polymer.

[0060] [(E) Carbon Black]

[0061] The carbon black (E) used as an optional component in the present invention is not particularly limited, as long as it is a commonly available carbon black used for resin coloration. Typically, carbon black (E) contains aggregates formed by aggregation of primary particles. However, unless a significant amount of aggregates of 50 μm or larger are contained, many bumps (fine pimple-like protrusions (fine irregularities) formed by aggregation of carbon black) are unlikely to occur on the surface of a molded article obtained by molding the resin composition of the present invention. When the content of particles with a particle diameter of 50 μm or larger is 20 ppm or less, the effect of suppressing nap formation on the surface of the molded article is likely to be enhanced. A preferred content is 5 ppm or less.

[0062] The content of (E) carbon black is preferably in the range of 0.5 to 5% by mass based on the total liquid crystal resin composition. When the carbon black content is 0.5% by mass or more, the jet blackness of the resulting resin composition is less likely to decrease, and concerns about light-blocking properties are less likely to arise. When the carbon black content is 5% by mass or less, it is less likely to be uneconomical and particles are less likely to occur. The content of (E) carbon black is more preferably 1 to 4% by mass, and even more preferably 2 to 3% by mass.

[0063] [Other Components] To the liquid crystalline resin composition of the present invention, other polymers, other fillers, and known substances generally added to synthetic resins, i.e., stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, colorants such as dyes and pigments, lubricants, mold release agents, crystallization accelerators, crystal nucleating agents, etc., may be added as appropriate depending on the required performance, within a range that does not impair the effects of the present invention.

[0064] Examples of other polymers include epoxy group-containing styrene polymers. Examples of epoxy group-containing styrene polymers include known epoxy group-containing styrene polymers, including copolymers composed of repeating units derived from styrenes and repeating units derived from a glycidyl ester of an α,β-unsaturated acid. Examples of other fillers include fillers other than (B) granular fillers, (C) plate-like fillers, and (E) carbon black, such as fibrous fillers such as glass fibers.

[0065] [Preparation of Liquid Crystalline Resin Composition] The preparation of the resin composition of the present invention is not particularly limited. For example, the liquid crystal resin composition is prepared by blending the above-mentioned components (A), (B), (C), (D), optionally the component (E), and optionally other components, and melt-kneading them using a single-screw or twin-screw extruder.

[0066] [Liquid Crystalline Resin Composition] From the viewpoint of fluidity, the melt viscosity of the liquid crystal resin composition of the present invention obtained as described above is preferably 60 Pa·s or less, more preferably 58 Pa·s or less, and even more preferably 57 Pa·s or less. The lower limit of the melt viscosity is not particularly limited, and may be 5 Pa·s or more, 10 Pa·s or more, or 20 Pa·s or more. One of the features of the liquid crystal resin composition of the present invention is that it has high fluidity when melted and excellent moldability. In this specification, the melt viscosity is defined as the viscosity at a cylinder temperature 10 to 30°C higher than the melting point of the liquid crystal resin, a shear rate of 1000 sec －１ The value obtained by the measurement method in accordance with ISO 11443 under the above conditions is adopted.

[0067] <Camera module components and camera modules>

[0068] The liquid crystalline resin composition can be used for camera module components. More specifically, the liquid crystalline resin composition can be used to produce camera module components. That is, camera module components can be produced using the liquid crystalline resin composition. Using the resin composition of the present invention as a raw material reduces the surface of camera module components from becoming napped. Camera module components are ultrasonically cleaned, and therefore, it is required that the surface is less likely to become napped even after ultrasonic cleaning. Using the resin composition of the present invention reduces the generation of debris that can cause dust, even when ultrasonic cleaning of camera module components is performed under stronger conditions. Furthermore, since a molded article containing the liquid crystalline resin composition of the present invention has excellent low sliding wear properties, the surface of a camera module component produced using the liquid crystalline resin composition is less likely to produce debris that can cause dust, etc., when components slide against each other. Therefore, after the camera module component is incorporated into a finished product, the quality of the finished product is less likely to be affected by the napped or sliding wear of the surface of the camera module component. The molded article can be obtained by molding the liquid crystalline resin composition of the present invention. The molding method is not particularly limited, and examples include injection molding.

[0069] A camera module component made of a molded article containing the liquid crystalline resin composition of the present invention will now be described. A cross section of a typical camera module is shown schematically in Figure 1. As shown in Figure 1, camera module 1 includes substrate 10, image sensor 11, lead wiring 12, lens holder 13, barrel 14, lens 15, IR filter 16, guide 17, base 18, coil 19, permanent magnet 20, yoke 21, and cover 22.

[0070] The imaging element 11 is disposed on a substrate 10 , and the imaging element 11 and the substrate 10 are electrically connected by lead wiring 12 .

[0071] The guide 17 is disposed on the substrate 10, the base 18 is disposed on the guide 17, the lens holder 13 is disposed on the base 18 so as to be movable up and down, and a coil 19 is wound around the lens holder 13. An opening is formed at the top of the lens holder 13, and a spiral groove is formed on the wall of this opening. The guide 17 has an opening formed at the top, and an IR filter 16 is disposed on the guide 17 so as to close this opening. The guide 17 and the IR filter 16 cover the imaging element 11. A yoke 21 is disposed on the base 18, and a permanent magnet 20 contacts the inside of the yoke 21, and a cover 22 with an opening formed at the top is disposed on the yoke 21. The permanent magnet 20 is disposed around the coil 19.

[0072] The barrel 14 is cylindrical, and the lens 15 is held substantially horizontally inside the cylindrical interior. A spiral convex portion is formed on the side wall of one end of the cylinder. This spiral convex portion screws into a spiral groove formed on the opening wall surface of the lens holder 13, thereby connecting the barrel 14 to the lens holder 13. As shown in FIG. 1 , the IR filter 16 and the lens 15 are arranged substantially parallel to each other. Leaf springs (not shown) are connected between the top of the lens holder 13 and the top of the yoke 21, and between the bottom of the lens holder 13 and the top of the base 18, thereby holding the lens holder 13 and, via the lens holder 13, the barrel 14, the lens 15, and the coil 19 within the camera module 1.

[0073] 1, the lens holder 13 moves up and down on the base 18 due to the action of the magnetic force generated by the coil 19 wound around the lens holder 13 and the permanent magnets 20 arranged around the coil 19, thereby changing the distance between the lens 15 and the imaging element 11. The focus of the camera can be adjusted by adjusting this distance.

[0074] In the camera module 1 as described above, the lens holder 13, guide 17, and / or base 18, which are camera module components, can be manufactured using the liquid crystalline resin composition of the present invention as a raw material. A general liquid crystalline resin composition is not suitable as a raw material for manufacturing these components. Manufacturing the lens holder 13, guide 17, and / or base 18 using a general liquid crystalline resin composition as a raw material results in the following problems.

[0075] In a molded article made from a general liquid crystalline resin composition, the molecular orientation of the polymer is particularly large at the surface, so the surface of the molded article is prone to raising, which causes small particles of dust to be generated. If this small particle of dust adheres to the lens 15, etc., the performance of the camera module will deteriorate.

[0076] Camera module components such as the lens holder 13, guide 17, and base 18 are ultrasonically cleaned before being assembled into the camera module 1 in order to remove dust and small debris from their surfaces. However, the surfaces of molded articles made by molding a general liquid crystalline resin composition tend to become napped, and ultrasonic cleaning causes the surfaces to become fluffy. Because of this problem, it is usually not possible to ultrasonically clean molded articles made by molding a liquid crystalline resin composition.

[0077] The focus adjustment is performed by moving the lens holder 13 up and down on the base 18 due to the action of the magnetic force generated by the coil 19 wound around the lens holder 13 and the permanent magnet 20 arranged around the coil. In this case, since a molded product made from a general liquid crystalline resin composition has a tendency to have a raised surface, as described above, the surface may peel off, producing peeled material. This peeled material may turn into small particles that may adhere to the lens 15, etc., and reduce the performance of the camera module.

[0078] As mentioned above, problems are usually likely to occur when a liquid crystalline resin composition is used as a raw material for the lens holder 13, guide 17, and / or base 18. On the other hand, a molded article containing the liquid crystalline resin composition of the present invention is less likely to develop nap problems even after ultrasonic cleaning, and has an improved surface condition. Furthermore, on the surface of a camera module part manufactured using the liquid crystalline resin composition of the present invention, debris that can cause dust and the like is less likely to fall off when the components slide against each other. Therefore, the liquid crystalline resin composition of the present invention can be preferably used as a raw material for the lens holder 13, guide 17, and / or base 18.

[0079] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0080] <Liquid Crystalline Resin> Aromatic Polyesteramide Resin The following raw materials were charged into a polymerization vessel, and the temperature of the reaction system was raised to 140°C and allowed to react at 140°C for 1 hour. The temperature was then further raised to 340°C over 4.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes. Melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized pressure. The polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were heat-treated at 300°C for 2 hours under a nitrogen stream to obtain the target polymer. The melting point of the obtained polymer was 336°C, and the melt viscosity at 350°C was 19.0 Pa·s. The melt viscosity of the above polymer was measured using the same method for measuring melt viscosity as described below. 4-Hydroxybenzoic acid (HBA): 1380 g (60 mol%), 6-hydroxy-2-naphthoic acid (HNA): 157 g (5 mol%), 1,4-phenylenedicarboxylic acid (TA): 484 g (17.5 mol%), 4,4'-dihydroxybiphenyl (BP): 388 g (12.5 mol%), N-acetyl-p-aminophenol (APAP): 126 g (5 mol%), metal catalyst (potassium acetate catalyst): 110 mg, acylating agent (acetic anhydride): 1659 g

[0081] Aromatic Polyester Resin: After the following raw materials were charged into a polymerization vessel, the temperature of the reaction system was raised to 140°C and allowed to react at 140°C for 1 hour. The temperature was then further raised to 330°C over 3.5 hours, and the pressure was then reduced to 10 Torr (i.e., 1330 Pa) over 15 minutes. Melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low-boiling components. After the stirring torque reached a predetermined value, nitrogen was introduced to change the pressure from reduced pressure to normal pressure and then to pressurized pressure. The polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain the target polymer. The melting point of the obtained polymer was 323°C, and the melt viscosity at 340°C was 38.3 Pa s. The melt viscosity of the above polymer was measured using the same method for measuring melt viscosity as described below. 4-Hydroxybenzoic acid (HBA): 2524 g (79.3 mol%), 6-hydroxy-2-naphthoic acid (HNA): 867 g (20 mol%), 1,4-phenylenedicarboxylic acid (TA): 27 g (0.7 mol%), metal catalyst (potassium acetate catalyst): 150 mg, acylating agent (acetic anhydride): 2336 g

[0082] [Method of measuring melting point] Using a DSC manufactured by TA Instruments, the liquid crystalline resin was heated from room temperature at a temperature increase rate of 20°C / min to measure the endothermic peak temperature (Tm1) observed, and then held at a temperature of (Tm1+40)°C for 2 minutes. After that, the resin was cooled to room temperature at a temperature decrease rate of 20°C / min, and then heated again at a temperature increase rate of 20°C / min to measure the endothermic peak temperature (Tm2), which was determined as the melting point of the polymer.

[0083] <Materials other than liquid crystalline resin> Mica: AB-25S (manufactured by Yamaguchi Mica Co., Ltd., mica, median diameter 25.0 μm) Silica: Denka fused silica FB-5SDC (manufactured by Denka Co., Ltd., silica, median diameter 4.0 μm) Carbon black: VULCAN XC305 (manufactured by Cabot Japan Co., Ltd., average particle size 20 nm, proportion of particles having a particle size of 50 μm or more being 20 ppm or less) Ethylene-glycidyl methacrylate copolymer 1: Bondfast BF-2C (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate copolymer, glycidyl methacrylate content 6% by mass) Ethylene-glycidyl methacrylate copolymer 2: Bondfast BF-7L (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate-methyl acrylate copolymer, glycidyl methacrylate content 3% by mass, methyl acrylate content 27% by mass) Epoxy group-free olefin polymer: Excellen G201-M (Sumitomo Chemical Co., Ltd., low-density polyethylene)

[0084] <Production of Liquid Crystalline Resin Composition> The above components were melt-kneaded in the proportions (% by mass) shown in Table 1 or Table 2 using a twin-screw extruder (TEX30α type, manufactured by The Japan Steel Works, Ltd.) at the following cylinder temperatures to obtain liquid crystal resin composition pellets. [Production conditions] Cylinder temperature: 350°C: for liquid crystal resin compositions containing the aromatic polyester amide resin 340°C: for liquid crystal resin compositions containing the aromatic polyester resin

[0085] <Melt Viscosity> Using a Capillograph 1B model manufactured by Toyo Seiki Seisakusho Co., Ltd., the melt viscosity was measured at a temperature 10 to 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 sec. －１The melt viscosity of the liquid crystalline resin composition was measured in accordance with ISO 11443. The specific measurement temperature was 350°C for the liquid crystalline resin composition containing the aromatic polyester amide resin, and 340°C for the liquid crystalline resin composition containing the aromatic polyester resin. The melt viscosity was used as an index representing the fluidity of the liquid crystalline resin composition. That is, when the melt viscosity was 60 Pa·s or less, the fluidity was evaluated as good, and when the melt viscosity was more than 60 Pa·s, the fluidity was evaluated as poor. The results are shown in Tables 1 and 2.

[0086] <Number of dust particles generated> The pellets of the examples and comparative examples were molded under the following molding conditions using a molding machine ("SE30DUZ" manufactured by Sumitomo Heavy Industries, Ltd.) to obtain molded bodies of 12.5 mm x 120 mm x 0.8 mm. These molded bodies were used as test pieces. [Molding conditions] Cylinder temperature: 350°C (Examples 1 to 6 and Comparative Examples 1 to 6) 340°C (Example 7) Mold temperature: 80°C Injection speed: 100 mm / sec

[0087] [Evaluation] The test piece was subjected to an ultrasonic cleaner (output: 300 W, frequency: 45 kHz) in room temperature water (80 ml) for 3 minutes. Thereafter, the number of particles of 2 μm or more present in the water was measured using a particle counter (Liquid Particle Counter KL-11A (PARTICLE COUNTER) manufactured by RION Corporation), and the number of dust particles generated in 10 ml was calculated. The number of dust particles generated was used as an index representing the low dust generation property of the molded article. That is, if the number of dust particles generated in 10 ml was less than 50,000 particles / mL, the low dust generation property was evaluated as good, and if the number of dust particles generated in 10 ml was 50,000 particles / mL or more, the low dust generation property was evaluated as poor. The results are shown in Tables 1 and 2.

[0088] <Low Sliding Wear Properties> The pellets of the Examples and Comparative Examples were molded under the following molding conditions using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries, Ltd.) to obtain a measurement pin (diameter 10 mm, length 10 mm) and a measurement test piece (12.5 mm x 120 mm x 0.8 mm). As shown in FIG. 2 , a load was applied to the measurement pin on the measurement test piece, and a reciprocating sliding test was performed under the following reciprocating sliding conditions. The surface of the measurement test piece was then visually inspected, and the low sliding wear properties of the molded product were evaluated according to the following criteria. The results are shown in Tables 1 and 2. ◯ (Good): No dust was generated on the surface of the measurement test piece. × (Poor): Dust was generated on the surface of the measurement test piece. [Molding conditions] Cylinder temperature: 350°C (Examples 1 to 6 and Comparative Examples 1 to 6) 340°C (Example 7) Mold temperature: 80°C Injection speed: 33 mm / sec [Reciprocating sliding conditions] Sliding speed: 50 mm / sec Stroke: 20 mm Load: 0.98 N (0.1 kgf) Number of reciprocating movements: 1000

[0089] <Camera Module Flatness> The pellets of the examples and comparative examples were molded using a molding machine ("SE30DUZ" manufactured by Sumitomo Heavy Industries, Ltd.) under the following molding conditions to obtain a camera module molded product measuring 10.0 mm x 10.0 mm x 1.0 mm as shown in FIG. 3( a). The obtained camera module molded product was placed on a horizontal table, and the height of the camera module molded product was measured using a Mitutoyo QuickVision 404 PRO CNC image measuring instrument. The height was measured at multiple positions indicated by black circles in FIG. 3( b), and the difference between the maximum height and the minimum height from the least-squares plane was defined as the camera module flatness. The camera module flatness was used as an index of the low warpage of the molded product. That is, when the camera module flatness was 0.07 mm or less, the low warpage was evaluated as good, and when the camera module flatness was greater than 0.07 mm, the low warpage was evaluated as poor. The results are shown in Tables 1 and 2. [Molding conditions] Cylinder temperature: 350°C (Examples 1 to 6 and Comparative Examples 1 to 6) 340°C (Example 7) Mold temperature: 80°C Injection speed: 100 mm / sec Holding pressure: 50 MPa

[0090] <Evaluation of inward collapse deformation> A liquid crystalline resin composition was injection molded under the following molding conditions to obtain a U-shaped liquid crystalline resin molded article (thickness: 0.5 mm) as shown in Figures 4(a) and 4(b). An image dimension measuring instrument IM-6020 manufactured by Keyence Corporation was used to measure angle A (gate side) and angle B (anti-gate side) as shown in Figure 2(4). The average of angle A and angle B was calculated and used as an index representing the dimensional accuracy of the molded article. The dimensional accuracy of the molded article was evaluated according to the following criteria. The results are shown in Tables 1 and 2. ○ (Good): The average of angle A and angle B was 87.3° or more. × (Bad): The average of angle A and angle B was less than 87.3°. [Molding conditions] Molding machine: Sumitomo Heavy Industries, SE30DUZ Cylinder temperature: 350°C Mold temperature: 90°C Injection speed: 100 mm / sec

[0091] <Bending test> The pellets of the examples and comparative examples were molded under the following molding conditions using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries, Ltd.) to obtain ISO type A test specimens. These test specimens were cut out to obtain measurement specimens (80 mm x 10 mm x 4 mm). Using these measurement specimens, the bending strength and bending modulus were measured in accordance with ISO 178. The results are shown in Tables 1 and 2. [Molding conditions] Cylinder temperature: 350°C (Examples 1 to 6 and Comparative Examples 1 to 6) 340°C (Example 7) Mold temperature: 90°C Injection speed: 33 mm / sec

[0092]

[0093]

[0094] As is clear from the results shown in Tables 1 and 2, the liquid crystalline resin compositions of the examples were able to give molded articles with a good balance of low dust generation, low sliding wear, low warpage, and suppression of inward collapse deformation, and were confirmed to have good fluidity.

[0095] REFERENCE SIGNS LIST 1 camera module 10 substrate 11 imaging element 12 lead wiring 13 lens holder 14 barrel 15 lens 16 IR filter 17 guide 18 base 19 coil 20 permanent magnet 21 yoke 22 cover

Claims

1. A liquid crystalline resin composition comprising (A) a liquid crystalline resin, (B) a granular filler, (C) a plate-like filler, and (D) an olefin-based polymer, wherein the median diameter of the (B) granular filler is 0.3 to 8 μm, the median diameter of the (C) plate-like filler is 10 to 50 μm, and the (D) olefin-based polymer comprises an epoxy group-containing olefin-based polymer, and the liquid crystalline resin composition has a content of the (A) liquid crystalline resin of 52 to 82% by mass, a content of the (B) granular filler of 2.5 to 35% by mass, a content of the (C) plate-like filler of 5 to 35% by mass, a total content of the (B) granular filler and the (C) plate-like filler of 15 to 45% by mass, and a content of the (D) olefin-based polymer of 1.50 to 6.00% by mass, The liquid crystal resin composition has an epoxy group content of 0.003 to 0.050% 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 granular filler (B) comprises one or more selected from the group consisting of silica and barium sulfate, and the plate-like filler (C) comprises one or more selected from the group consisting of talc and mica.

4. The liquid crystalline resin composition according to claim 1 or 2, which is used for a camera module part.

5. Use of the liquid crystal resin composition according to claim 1 or 2 for producing a camera module part.

6. A molded article comprising the liquid crystal resin composition according to claim 1 or 2.

7. A camera module part comprising the molded article according to claim 6.

8. A camera module comprising the camera module component according to claim 7.

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