TW202028300A - Liquid crystalline resin composition for ball bearing anti-sliding-abrasion member, and ball bearing anti-sliding-abrasion member using same - Google Patents

Abstract

Provided are: a liquid crystalline resin composition for a ball bearing anti-sliding-abrasion member, the composition being used to manufacture a ball bearing anti-sliding-abrasion member which has excellent surface whitening suppression, low warpage properties, weld strength, and low dust generation in a good balance, and whereby sliding abrasiveness of a ball bearing is reduced; and a ball bearing anti-sliding-abrasion member which uses the liquid crystalline resin composition. The liquid crystalline resin composition for a ball bearing anti-sliding-abrasion member pertaining to the present invention contains a liquid crystalline resin (A), a particulate filler (B), and a platy filler (C), the median diameter of the particulate filler (B) being 1.3-5.0 [mu]m, the content of the particulate filler (B) being 7.5-22.5% by mass, the content of the platy filler (C) being 2.5-27.5% by mass, and the total content of the particulate filler (B) and the platy filler (C) being 22.5-37.5% by mass.

Description

Liquid crystal resin composition for ball bearing sliding wear resistant parts and ball bearing sliding wear resistant parts using the liquid crystal resin composition

The present invention relates to a liquid crystalline resin composition for a ball bearing sliding wear resistant member and a ball bearing sliding wear resistant member using the liquid crystalline resin composition.

Liquid crystal resins represented by liquid crystal polyester resins have good balance of mechanical strength, heat resistance, chemical resistance, electrical properties, etc., and have excellent dimensional stability, so they are widely used as high-functional engineering plastic. Recently, liquid crystalline resins have effectively used these characteristics to be used in precision machine parts.

Examples of parts using liquid crystal resin include connectors such as FPC connectors; sockets such as memory card slots; parts for camera modules such as lens holders; and relays. These parts are required to suppress surface whitening, low bendability, weld strength, and low dust generation. In addition, because they are used in a form where two or more parts are in contact with each other, they are also required to reduce sliding Abrasion (that is, the ease of abrasion when two or more components come into contact with each other). For example, in Patent Document 1, a subject is to provide a molded article composed of a liquid crystalline resin composition having excellent surface appearance and excellent sliding properties, and it is disclosed that a liquid crystalline resin and a talc having a specific volume average particle diameter are contained in a specific ratio. Liquid crystal resin composition.

Among the above-mentioned parts, when a molded body composed of a liquid crystalline resin composition and a ball bearing are used in a form of movable contact, it is particularly required to reduce the sliding wear resistance of the ball bearing (that is, when it is in movable contact with the ball bearing) Ease of wear). Furthermore, Patent Document 2 describes a component for a camera module that can be used in a form of movable contact with a ball bearing. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5087958 [Patent Document 2] European Patent No. 2938063 Specification

[The problem to be solved by the invention]

However, according to the research of the present inventors, with the conventional liquid crystal resin composition, the reduction in the sliding wear properties of the ball bearing is insufficient. The present invention was accomplished in order to solve the above-mentioned problems, and its purpose is to provide an excellent balance of surface whitening suppression, low bendability, weld strength, and low dust generation, and reduced sliding wear properties of ball bearings. A liquid crystal resin composition for a ball bearing sliding wear resistant part, which is a ball bearing sliding wear resistant part, and a ball bearing sliding wear resistant part using the liquid crystal resin composition. [Means used to solve the problem]

The inventors of the present invention have devoted themselves to repeated researches to solve the above-mentioned problems. As a result, it was found that by using a granular filler and a plate-shaped filler containing a liquid crystalline resin and a specific intermediate diameter, each content of the granular filler, the plate-shaped filler, and the total of these are contained in a predetermined range The liquid crystal resin composition of the above can solve the above-mentioned problems, and the present invention has been completed. More specifically, the present invention provides the following.

(1) A liquid crystal resin composition for ball bearing sliding wear resistant parts, containing: (A) liquid crystal resin, (B) granular filler and (C) plate filler, the above (B) granular filler The median diameter of the above-mentioned (B) granular filler is 7.5-22.5% by mass, the above-mentioned (C) platy filler content is 2.5-27.5% by mass, and the above (B) granular filler The total content of the above-mentioned (C) platy filler is 22.5 to 37.5% by mass.

(2) The composition according to (1), wherein the (B) granular filler is silica, and the (C) plate filler is talc.

(3) The composition as described in (1) or (2), further containing (D) an epoxy group-containing copolymer, and the content of the above (D) epoxy group-containing copolymer is 1 to 5% by mass.

(4) A ball bearing resistant sliding wear component composed of the composition described in any one of (1) to (3). [Effects of the invention]

Using the liquid crystal resin composition for ball bearing sliding wear resistant parts of the present invention as a raw material to produce ball bearing sliding wear resistant parts can suppress surface whitening, low bendability, weld strength, and low dust generation Ball bearing sliding wear resistant parts with excellent balance and reduced sliding wear of ball bearings.

Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment.

>Liquid crystal resin composition for ball bearing sliding wear resistant parts> The liquid crystal resin composition for ball bearing sliding wear resistant parts of the present invention contains (A) liquid crystal resin, (B) granular filler, and (C) plate filler.

[(A) Liquid crystal resin] 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 properties of the anisotropic melt phase can be confirmed by a conventional polarization inspection method using a crossed polarizer. More specifically, the confirmation of the anisotropic melt phase was performed by using a Leitz polarizing microscope to observe the molten sample placed on a Leitz hot stage under a nitrogen atmosphere at a magnification of 40 times. The liquid crystalline polymer applicable to the present invention can allow polarized light to pass through normally and exhibit optical anisotropy even when it is in a molten static state when inspecting between crossed polarizers.

The type of the above-mentioned (A) liquid crystal resin is not particularly limited, but aromatic polyester and/or aromatic polyester amide are preferred. In addition, a polyester partially containing an aromatic polyester and/or an aromatic polyesteramide in the same molecular chain is also within the range. (A) Liquid crystal resin can be used well when dissolved in pentafluorophenol at a concentration of 0.1% by mass at 60°C, preferably at least about 2.0d1/g, and more preferably 2.0~10.0d1/g The logarithmic viscosity (IV).

The aromatic polyester or aromatic polyester amide that can be applied to the present invention as the (A) liquid crystal resin, and particularly preferably has a composition selected from aromatic hydroxycarboxylic acid, aromatic hydroxyamine, and aromatic diamine At least one compound of the group is an aromatic polyester or an aromatic polyesteramide as a repeating unit of a constituent component.

More specifically, one can cite (1) A polyester mainly composed of one or more repeating units from aromatic hydroxycarboxylic acids and their derivatives; (2) It is mainly composed of one or more repeating units from (a) aromatic hydroxycarboxylic acid and its derivatives, and from (b) aromatic dicarboxylic acid, alicyclic dicarboxylic acid and its derivatives Polyester composed of one or more repeating units; (3) It is mainly composed of one or more repeating units from (a) aromatic hydroxycarboxylic acid and its derivatives, and from (b) aromatic dicarboxylic acid, alicyclic dicarboxylic acid and its derivatives One or more repeating units of (c) aromatic diols, cycloaliphatic diols, aliphatic diols and their derivatives, and at least one or more repeating units consisting of ester; (4) It is mainly composed of one or two or more repeating units derived from (a) aromatic hydroxycarboxylic acid and its derivatives, and one derived from (b) aromatic hydroxyamine, aromatic diamine and its derivatives. One or more repeating units, and (c) a polyester amide consisting of one or more repeating units of aromatic dicarboxylic acid, alicyclic dicarboxylic acid and derivatives thereof; (5) It is mainly composed of one or two or more repeating units derived from (a) aromatic hydroxycarboxylic acid and its derivatives, and one derived from (b) aromatic hydroxyamine, aromatic diamine and its derivatives. One or more repeating units, and one or more repeating units derived from (c) aromatic dicarboxylic acid, alicyclic dicarboxylic acid and their derivatives, and (d) aromatic diol , Alicyclic diols, aliphatic diols and their derivatives, and polyester amides composed of at least one or two or more repeating units. In addition, if necessary, a molecular weight modifier may be used together with the above-mentioned constituents.

(X︰選自由亞烷基(alkylene)(C₁ ~C₄ )、亞烯基(alkylidene)、-O-、-SO-、-SO₂ -、-S-、及-CO-之基) [化2]

[化3]

(Y︰選自由-(CH₂ )_n -(n=1~4)及-O(CH₂ )_n O-(n=1~4)之基。)Preferable examples of specific compounds constituting (A) liquid crystal resin applicable to the present invention include aromatic hydroxycarboxylic acids such as p-hydroxybenzoic acid and 6-hydroxy-2-naphthoic acid, 2,6- Dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 4,4'-dihydroxybiphenyl, hydroquinone, resorcinol, compounds represented by the following general formula (I), and the following general formula Aromatic diols such as compounds represented by formula (II); terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and the following general formula ( III) Aromatic dicarboxylic acids such as compounds; aromatic amines such as aminophenol and phenylenediamine. [化1]

(X: group selected from alkylene (C ₁ ~C ₄ ), alkylidene, -O-, -SO-, -SO ₂ -, -S-, and -CO-) [化2]

[化3]

(Y: Choose from -(CH ₂ ) _n -(n=1~4) and -O(CH ₂ ) _n O-(n=1~4).)

The preparation of (A) liquid crystal resin used in the present invention can be carried out by the conventional method of direct polymerization or transesterification from the above-mentioned monomer compound (or a mixture of monomers), usually melt polymerization and solution polymerization are used. , Slurry polymerization method, solid phase polymerization method, etc., or a combination of two or more of these, more preferably a melt polymerization method, or a combination of a melt polymerization method and a solid phase polymerization method. The above-mentioned compounds having ester forming energy can be polymerized in their original form, or they can be modified from precursors to derivatives having the ester forming energy at the stage before polymerization. In the polymerization, various catalysts can be used. Representative examples include potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, Metal salt catalysts such as (2,4-pentanedione) cobalt (III), organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The usage amount of the catalyst is generally about 0.001 to 1% by mass based on the total mass of the monomer, and is particularly preferably about 0.01 to 0.2% by mass. For polymers produced by these polymerization methods, if necessary, the molecular weight can be increased by a solid-phase polymerization method heated under reduced pressure or in an inert gas.

The melt viscosity of (A) liquid crystalline resin obtained by the method described above is not particularly limited. Generally, the melt viscosity used for forming temperature is 3Pa when the shear speed is 1000sec ^-1 . 500Pa above s. s or less. However, if the viscosity is too high, the fluidity will deteriorate very badly. In addition, the above-mentioned (A) liquid crystal resin may be a mixture of two or more liquid crystal resins.

In the liquid crystal resin composition of the present invention, the content of (A) liquid crystal resin is preferably 62.5-77.5 mass% or 61.5-72.5 mass%, more preferably 65-77.5 mass% or 63.5-72.5 mass% . (A) When the content of the component is within the above range, it is preferable in terms of fluidity and heat resistance.

[(B) Granular filler] The component (B) is a granular filler, and the median diameter of the component (B) is 1.3 to 5.0 μm. If the above-mentioned intermediate diameter is 1.3 μm or more, the weld strength of the molded body is likely to increase. When the above-mentioned intermediate diameter is 5.0 μm or less, the effect of suppressing whitening on the surface of the molded body is likely to increase. The above-mentioned intermediate diameter is preferably 1.5 to 5.0 μm, more preferably 1.5 to 4.0 μm. In addition, in this specification, the "intermediate diameter" refers to the volume-based median value measured by the laser diffraction/scattering particle size distribution measurement method.

As the granular filler of the component (B), for example, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, silica fume Silicates such as wollastonite; metal oxides such as iron oxide, titanium oxide, zinc oxide, and aluminum oxide; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; carbonization Silicon, silicon nitride, boron nitride, etc. (B) A component may be used individually by 1 type or in combination of 2 or more types. In the present invention, it is preferable to use silica as the component (B) from the viewpoints of suppressing whitening of the surface of the molded body, low dust generation properties of the molded body, and welding strength of the molded body.

(B) The content of the component is 7.5 to 22.5% by mass in the liquid crystal composition of the present invention. When the content of the component (B) is 7.5% by mass or more, it is easy to obtain a molded body with reduced sliding wear properties of the ball bearing, and when the content of the component is 22.5% by mass or less, the effect of suppressing whitening on the surface of the molded body is likely to increase. The preferable content of (B) component is 10-20 mass %.

[(C) Plate filler] The liquid crystal resin composition of the present invention contains a platy filler. The plate filler can be used alone or in combination of two or more.

In the liquid crystal resin composition of the present invention, the content of the (C) platy filler is 2.5 to 27.5 mass%. When the content of the component (C) is 2.5% by mass or more, the low bendability of the molded body is likely to increase. (C) When the content of the component is 27.5% by mass or less, the effect of suppressing whitening of the surface of the molded body and the low dust generation property of the molded body are likely to increase. (C) The content of the component is preferably 5 to 25% by mass.

The plate-like filler of the present invention includes talc, mica, glass flake, various metal foils, and the like. In order to prevent the fluidity of the liquid crystalline resin composition from deteriorating and to suppress the bending deformation of the molded body obtained from the liquid crystalline resin composition, talc is preferred. The median diameter of the platy filler is not particularly limited, but considering the fluidity of the liquid crystalline resin composition, it is preferably smaller. On the other hand, in order to reduce the bending deformation of the molded body obtained from the liquid crystalline resin composition, it is necessary to maintain a certain size. Specifically, 1-100μm is preferred, and 5-50μm is more preferred.

(Talc) As the talc that can be used in the present invention, the total content of Fe ₂ O ₃ , Al ₂ O ₃ and CaO is 2.5% by mass or less based on the total solid content of the talc, Fe ₂ O ₃ and Al ₂ O ₃ It is preferable that the total content of Zn is more than 1.0% by mass and less than 2.0% by mass, and the content of CaO is less than 0.5% by mass. That is, the talc that can be used in the present invention may contain at least one of Fe ₂ O ₃ , Al ₂ O ₃ and CaO in addition to the main components of SiO ₂ and MgO, and may contain within the above-mentioned content range. The ingredients.

In the above-mentioned talc, if the total content of Fe ₂ O ₃ , Al ₂ O ₃ and CaO is 2.5% by mass or less, the molding processability of the liquid crystalline resin composition and the connector formed from the liquid crystalline resin composition are The heat resistance of the molded body is unlikely to deteriorate. Therefore, the total content of Fe ₂ O ₃ , Al ₂ O ₃ and CaO is preferably 1.0% by mass or more and 2.0% by mass or less.

In addition, among the aforementioned talc, talc having a total content of Fe ₂ O ₃ and Al ₂ O ₃ exceeding 1.0% by mass is easy to obtain. In addition, when the total content of Fe ₂ O ₃ and Al ₂ O ₃ in the above talc is 2.0% by mass or less, the molding processability of the liquid crystalline resin composition and the connector molded from the liquid crystalline resin composition are The heat resistance of the molded body is unlikely to deteriorate. Therefore, the total content of Fe ₂ O ₃ and Al ₂ O ₃ is preferably more than 1.0% by mass and 1.7% by mass or less.

In addition, when the content of CaO in the talc is less than 0.5% by mass, the molding processability of the liquid crystalline resin composition and the heat resistance of molded articles such as connectors molded from the liquid crystalline resin composition are unlikely to deteriorate. Therefore, the content of CaO is preferably 0.01% by mass or more and 0.4% by mass or less.

The median diameter of the talc of the present invention is preferably 4.0 to 20.0 μm, and more preferably 10 to 18 μm from the viewpoint of preventing bending deformation of the molded body and maintaining the fluidity of the liquid crystalline resin composition.

In addition, the total content of the (B) component and the (C) component is 22.5 to 37.5 mass% in the liquid crystal resin composition of the present invention, and preferably 25 to 35% by mass. If the above-mentioned total content is 22.5 mass% or more, the low bendability of the molded body is likely to increase. If the total content is 37.5 mass% or less, the effect of suppressing whitening of the surface of the molded body and the low dust generation property of the molded body are likely to increase.

[(D) Epoxy-containing copolymer] The liquid crystal composition of the present invention may also contain (D) an epoxy group-containing copolymer. (D) Epoxy group-containing copolymers can be used alone or in combination of two or more. (D) Epoxy group-containing copolymers are not particularly limited. For example, they may be selected from the group consisting of (D1) epoxy group-containing olefin copolymers and (D2) epoxy group-containing styrene copolymers At least one of them. (D) The epoxy group-containing copolymer can contribute to reducing the ball bearing sliding wear properties of the molded body obtained from the liquid crystalline resin composition of the present invention.

(D1) Epoxy group-containing olefin copolymers include, for example, copolymers composed of repeating units derived from α-olefins and repeating units derived from glycidyl esters of α,β-unsaturated acids.

The α-olefin is not particularly limited, and, for example, ethylene, propylene, butene, etc. can be preferably used, and among them, ethylene is preferably used. The glycidyl ester of α,β-unsaturated acid is represented by the following general formula (IV). The glycidyl esters of α,β-unsaturated acids include, for example, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconic acid, etc., especially glycidyl methacrylate good. [化4]

(D1) In the epoxy group-containing olefin copolymer, the content of the repeating unit derived from α-olefin is 87 to 98% by mass, and the content of the repeating unit derived from glycidyl ester of α, β-unsaturated acid is 13 to 2% by mass is preferable.

The (D1) epoxy-containing olefin-based copolymer used in the present invention may also be derived from acrylonitrile, acrylate, methacrylate, and α-methylstyrene without compromising the scope of the present invention. 1 or 2 or more of olefinic unsaturated esters such as anhydrous maleic acid as the third component other than the above two components, which contains 0 to 48 parts by mass relative to 100 parts by mass of the above two components.

As the epoxy group-containing olefin-based copolymer of the component (D1) of the present invention, a monomer and a radical polymerization catalyst corresponding to each component can be used, and it can be easily prepared by a general radical polymerization method. More specifically, in general, by the presence or absence of an appropriate solvent, chain transfer agent, etc., in the presence or absence of a free radical generator at 500-4000 atmospheres, 100-300°C It is produced by copolymerization of α-olefin and α,β-unsaturated acid glycidyl ester. In addition, it can also be produced by mixing α-olefins, α,β-unsaturated acid glycidyl esters and free radical generators, and melt grafting copolymerization in an extruder.

As the epoxy group-containing styrene copolymer of (D2), for example, a copolymer composed of a repeating unit derived from styrene and a repeating unit derived from a glycidyl ester of an α,β-unsaturated acid. Regarding the glycidyl ester of α,β-unsaturated acid, the description is omitted because it is the same as that described in the component (D1).

The styrenes include styrene, α-methylstyrene, brominated styrene, divinylbenzene, etc., and styrene is preferably used.

The (D2) epoxy-containing styrene copolymer used in the present invention may also be a multi-element copolymer containing repeating units derived from one or two or more other vinyl monomers, as the above 2 The third ingredient other than ingredients. Suitable as the third component is one or two or more repeating units derived from olefinic unsaturated esters such as acrylonitrile, acrylate, methacrylate, and anhydrous maleic acid. The copolymer preferably contains an epoxy-group-containing styrene-based copolymer of 40% by mass or less of these repeating units as the (D2) component.

In (D2) epoxy-containing styrene copolymers, the content of the repeating unit derived from α, β-unsaturated acid glycidyl ester is 2-20% by mass, and the content of the repeating unit derived from styrene is 80 ~98% by mass is better.

(D2) Epoxy group-containing styrene copolymers can be prepared by a general free radical polymerization method using monomers and radical polymerization catalysts corresponding to each component. More specifically, in general, the presence of a free radical generator at 500-4000 atmospheres, 100-300°C, in the presence or absence of appropriate solvents, chain transfer agents, etc. , β-Unsaturated acid glycidyl ester copolymerization method. In addition, it can also be produced by mixing styrenes with glycidyl esters of α,β-unsaturated acids and free radical generators, and melt-grafting them in an extruder.

Furthermore, as the (D) epoxy group-containing copolymer, (D1) the epoxy group-containing olefin copolymer is preferable in terms of heat resistance. When the (D1) component and the (D2) component are used together, the ratio of these components to each other can be appropriately selected according to the required characteristics.

(D) The content of the epoxy group-containing copolymer in the liquid crystalline resin composition of the present invention may be, for example, 0 to 5% by mass, and preferably 1 to 5% by mass. When the content of the component (D) is within the above range, the fluidity of the liquid crystalline resin composition is not impaired, and a molded body with reduced sliding wear properties of the ball bearing can be easily obtained. More preferably, the aforementioned content is 1.5 to 2.5% by mass.

[(E) Carbon Black] The (E) carbon black used as an optional component in the present invention is not particularly limited as long as it can be used for resin coloring and can be generally obtained. Generally, (E) carbon black contains agglomerates formed by agglomeration of primary particles, but as long as it does not significantly contain a lot of agglomerates with a size of 50 μm or more, it is not easy to form on the surface of the molded body formed by molding the resin composition of the present invention A lot of bumps (fine granular projections (fine bumps) of aggregated carbon black) occur. When the content of particles having a particle size of 50 μm or more is 20 ppm or less, the fuzz suppression effect on the surface of the molded body is likely to increase. The preferable content rate is 5 ppm or less.

(E) The mixing amount of carbon black can be, for example, 0 to 5% by mass in the liquid crystalline resin composition, preferably in the range of 0.5 to 5% by mass. When the blending amount of carbon black is 0.5% by mass or more, the pitch blackness of the obtained resin composition is not easily reduced, and the light-shielding properties are not easily disturbed. If the blending amount of carbon black is 5 mass% or less, it will not easily become uneconomical, and bumps will not easily occur. [(F) Release agent] The (F) release agent used as an optional component in the present invention is not particularly limited as long as it is generally available. Examples include fatty acid esters, fatty acid metal salts, fatty acid amides, and low molecular weight polyolefins. Etc., preferably fatty acid esters of pentaerythritol (for example, pentaerythritol tetrastearate).

(F) The mixing amount of the release agent can be, for example, 0 to 3% by mass in the liquid crystalline resin composition, preferably in the range of 0.1 to 3% by mass. If the mixing amount of the release agent is 0.1% by mass or more, the release property during molding can be improved, and at the same time, a molded body with reduced sliding wear properties of the ball bearing can be easily obtained. If the mixing amount of the release agent is 3% by mass or less, it is easy to reduce mold deposits (that is, adhesion to the mold during molding. Hereinafter, also referred to as "MD".).

[Other ingredients] In the liquid crystal resin composition of the present invention, other polymers, other fillers, and conventional substances generally added to synthetic resins may be appropriately added in accordance with the required performance within the range that does not hinder the effects of the present invention, that is, Other ingredients such as stabilizers such as oxidation inhibitors, ultraviolet absorbers, anti-charge agents, flame retardants, coloring agents such as dyes and pigments, lubricants, crystallization accelerators, crystal nucleating agents, etc. Other components may be used alone or in combination of two or more kinds.

The so-called other fillers refer to (B) granular fillers, (C) plate fillers, and (E) fillers other than carbon black. Examples include fibrous fillers such as whiskers. . However, from the viewpoint of the weld strength of the molded body, etc., the liquid crystalline resin composition of the present invention preferably does not contain a fibrous filler.

[Preparation method of liquid crystal resin composition for ball bearing sliding wear resistant parts] The preparation method of the liquid crystalline resin composition for ball bearing sliding wear resistant parts of this invention is not specifically limited. For example, the above (A) to (C) components, and at least one of the above (D) to (F) components and other components are optionally blended, and these are melt-kneaded using a single-axis or 2-axis extruder The treatment was performed to prepare a liquid crystalline resin composition for ball bearing sliding wear resistant parts.

[Liquid crystal resin composition for ball bearing sliding wear resistant parts]

The liquid crystalline resin composition of the present invention obtained as described above has a melt viscosity of 90Pa from the viewpoint of fluidity during melting and the viewpoint of moldability. sec or less is better, with 80Pa. sec or less is better. In this specification, the melt viscosity is the value obtained by following the ISO 11443 measurement method under the conditions of using a cylinder temperature 10-20°C higher than the melting point of the liquid crystal resin and a cutting speed of 1000sec ^-1 .

>Ball bearing sliding wear resistant parts> Using the liquid crystalline resin composition of the present invention, a ball bearing sliding wear resistant member is produced. The ball bearing sliding wear resistant component of the present invention suppresses surface whitening, has a good balance of low bendability, welding strength and low dust generation, and reduces the sliding wear of the ball bearing. The ball bearing sliding wear resistant component of the present invention can be used as a part that movably contacts with a ball bearing during use, specifically, for example, a lens holder used in a form of movably contact with a ball bearing and other camera module parts. [Example]

The following examples illustrate the present invention in more detail, but the present invention should not be limited to these examples.

>Liquid crystal resin> . Liquid crystalline polyester amide resin After putting the following raw materials in the polymerization vessel, the temperature of the reaction system was raised to 140°C and reacted at 140°C for 1 hour. After that, the temperature was increased to 340°C over a further 4.5 hours, and then the pressure was reduced to 10 Torr (that is, 1330 Pa) over 15 minutes, and melt polymerization was performed while distilling out acetic acid, excess anhydrous acetic acid, and other low-boiling components. After the stirring torque reaches a predetermined value, nitrogen is introduced from the reduced pressure state to the pressurized state through normal pressure, the polymer is discharged from the lower part of the polymerization vessel, and the strand is pelletized into pellets. The obtained pellets were subjected to a heat treatment at 300°C for 2 hours under a nitrogen stream to obtain the target polymer. The obtained polymer has a melting point of 336°C and a melt viscosity of 19.0Pa at 350°C. s. In addition, the melt viscosity of the said polymer is measured in the same way as the measuring method of the melt viscosity mentioned later. (I) 4-Hydroxybenzoic acid (HBA); 1380g (60 mol%) (II) 2-Hydroxy-6-naphthoic acid (HNA); 157g (5 mol%) (III) Terephthalic acid (TA); 484g (17.5 mol%) (IV) 4,4'-Dihydroxybiphenyl (BP); 388g (12.5 mol%) (V) 4-Acetoxyaminophenol (APAP); 126g (5 mol%) Metal catalyst (potassium acetate catalyst); 110mg Alcohol (anhydrous acetic acid); 1659g

>Materials other than liquid crystal resins> . Silicon dioxide 1: ADMAFINE SO-C4 (made by Admatechs (Co., Ltd.), silicon dioxide, intermediate diameter 1.0μm) . Silicon dioxide 2: ADMAFINE SO-C5 (made by Admatechs (Co., Ltd.), silicon dioxide, intermediate diameter 1.5μm) . Silicon dioxide 3: ADMAFINE SO-C6 (made by Admatechs (Co., Ltd.), silicon dioxide, intermediate diameter 2.0μm) . Silicon dioxide 4: DENKA molten silicon dioxide FB-5SDC (manufactured by Denka Chemical Industry Co., Ltd., silicon dioxide, middle diameter 4.0μm) . Alumina: ADMAFINE AO-502 (manufactured by Admatechs (Co., Ltd.), alumina, intermediate diameter 0.7μm) . Glass beads: EGB731 (manufactured by Potters-Ballotini (Co., Ltd.), glass beads, middle diameter 20.0μm) . Talc: CROWN TALC PP (manufactured by Matsumura Industry Co., Ltd., Talc, middle diameter 14.6μm) . Potassium titanate: TISMON-102 (manufactured by Otsuka Chemical Co., Ltd., potassium titanate fiber, average fiber diameter 0.3~0.6μm, average fiber length 10~20μm) . Wollastonite: NYGLOS 8 (manufactured by NYCO Materials, calcium silicate whiskers (wollastonite), average fiber length 136μm, average fiber diameter 8μm) . Epoxy-containing olefin-based copolymer: BONDFAST 2C (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate copolymer, glycidyl methacrylate content of 6 mass%) . Carbon black: VULCAN XC305 (manufactured by Cabot Japan (Co., Ltd.), with an average particle size of 20nm, the proportion of particles with a particle size of 50μm or more is 20ppm or less) . Release agent: Neopentylerythritol tetrastearate (manufactured by Emery Oleochemicals Japan (Co., Ltd.))

>Production of liquid crystal resin composition for ball bearing sliding wear resistant parts> The above-mentioned components were melted and kneaded at a barrel temperature of 350°C using a twin-screw extruder ((Co., Ltd.) Nippon Steel Works TEX30a type) in the proportions shown in Tables 1 to 4 (unit: mass %) to obtain ball bearings Liquid crystal resin composition particles for sliding wear parts.

>Surface whitening> The pellets of the Examples and Comparative Examples were molded using a molding machine ("SE30DUZ" manufactured by Sumitomo Heavy Industries Co., Ltd.) under the following molding conditions to obtain test pieces for measurement (12.5 mm×120 mm×0.8 mm). The test piece for measurement was applied to water (80 ml) at room temperature with an ultrasonic cleaner (output 300 W, frequency 45 kHz) for 3 minutes. After that, the surface of the test piece for measurement was visually observed. The surface whitening of the test piece for measurement was evaluated based on the following criteria. The results are shown in Tables 1 to 4. ○ (good): Whitening cannot be confirmed in the entire test piece. ○-(Slightly good): A little whitening can be confirmed near the gate and/or near the ejector pin mark. × (Failure): It can be confirmed that the smooth part of the test piece is clearly whitened. [Forming conditions] Material pipe temperature: 350℃ Mold temperature: 80℃ Injection speed: 100mm/sec

>Sliding wear resistance of ball bearings> The pellets of the Examples and Comparative Examples were molded using a molding machine ("SE100DU" manufactured by Sumitomo Heavy Industries Co., Ltd.) under the following molding conditions to obtain test specimens for measurement (80 mm × 80 mm × 1 mm). Using a light-load reciprocating testing machine, as shown in Figure 1, on the test piece 1 for measurement, a load is applied to the ball 4 (diameter 5mm, made of SUS) at the tip of the arm 3 via grease 2 to slide back and forth as follows Conditions After the reciprocating sliding test was performed, the width of the sliding traces of the ball bearing remaining on the test piece 1 for measurement was measured using a stereo microscope, and the sliding wear properties of the ball bearing were evaluated based on the following criteria. The results are shown in Tables 1 to 4. ○ (good): The width of the sliding trace of the ball bearing is 540 μm or less. × (Unqualified): The width of the sliding trace of the ball bearing exceeds 540 μm. [Forming conditions] Material pipe temperature: 350℃ Mold temperature: 80℃ Injection speed: 33mm/sec [Back and forth sliding condition] Sliding speed: 5cm/sec Stroke: 20mm Load: 29.6N (3kg weight) Number of round trips: 1000 times Grease: made by Dow Corning Toray (stock company), MOLYKOTE EM-30L

>Flexibility> The pellets of the Examples and Comparative Examples were molded using a molding machine ("SE30DUZ" manufactured by Sumitomo Heavy Industries Co., Ltd.) under the following molding conditions to obtain a camera of 10.0mm×10.0mm×1.0mm shown in Figure 2(a) Modular molded products. The obtained camera module-type molded article was placed on a horizontal table and allowed to stand still, and measured with a Quick Vision 404PROCNC video measuring machine manufactured by Mitutoyo. At this time, the height of the plural positions shown by black circles in Fig. 2(b) was measured, and the difference between the maximum height and the minimum height from the least square plane was regarded as the bending deformation. The flexibility was evaluated based on the following criteria. The results are shown in Tables 1 to 4. ○ (good): The bending deformation is 0.020 mm or less. △ (Slightly good): Bending deformation exceeds 0.020 mm and 0.025 mm or less. × (Failure): The bending deformation exceeds 0.025 mm. [Forming conditions] Material pipe temperature: 350℃ Mold temperature: 80℃ Injection speed: 100mm/sec Holding pressure: 50MPa

>Welding Strength> The pellets of the Examples and Comparative Examples were injection molded under the following molding conditions, and as shown in FIG. 3, an aperture test piece 10 (perforated flat plate 30mm×30mm×0.3mm, hole diameter 7mm) having a film gate 11 and a hole 12 was obtained. From the obtained perforated test piece 10, with the hole 12 sandwiched therebetween, a 4.5 mm wide part on the gate side and a 4.5 mm wide part on the reverse gate side were cut out, and these were used as test pieces 13a and 13b for measurement, respectively. The flexural strength of each of the measurement test pieces 13a and 13b was measured under the following measurement conditions. The flexural strength of the measurement test piece 13b on the counter-gate side was divided by the flexural strength of the measurement test piece 13a on the gate side to obtain the weld strength. The retention rate was evaluated by the following criteria for welding strength. The results are shown in Tables 1 to 4. ○ (good): The retention of weld strength is 55% or more. △ (Slightly good): The retention of weld strength is 45% or more and 55% or less. × (unacceptable): The retention rate of weld strength is 45% or less. [Forming conditions] Forming machine; Sumitomo Heavy Industries SE30DUZ Material pipe temperature; 350℃-350℃-350℃-340℃-330℃ Mold temperature; 90℃ Injection speed; 200mm/sec Holding pressure; 50MPa Holding pressure time; 2sec Cooling time; 8sec Spiral speed; 150rpm Spiral back pressure; 1MPa [Measurement conditions] Measuring machine; TENSILON universal test mechanism RTM-100 from OLIENTEC Load cell; 100kg Span: 4.8mm Bending speed: 2mm/min

>Number of dust occurrences> The pellets of the Examples and Comparative Examples were molded using a molding machine (“SE30DUZ” manufactured by Sumitomo Heavy Industries Co., Ltd.) under the following molding conditions to obtain molded bodies of 12.5 mm×120 mm×0.8 mm. This molded body was used as a test piece. [Forming conditions] Material pipe temperature: 350℃ Mold temperature: 80℃ Injection speed: 100mm/sec [Evaluation] The above test piece was applied to room temperature water (80 ml) with an ultrasonic cleaner (output 300 W, frequency 45 kHz) for 3 minutes. After that, a particle counter (RION (Co., Ltd.), an in-liquid particle counter KL-11A (PARTICLECOUNTER)) was used to measure the number of particles of 2 μm or more existing in the water and evaluate it as the number of dust generation. The results are shown in Tables 1 to 4.

[Table 1] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Comparative example 8 Comparative example 9 Liquid crystal resin Liquid crystalline polyester amide 93.7 88.7 83.7 78.7 83.7 78.7 68.7 68.7 68.7 Granular filler Silica 1 30 20 Silica 2 Silica 3 15 20 30 Silica 4 5 10 15 20 Alumina glass bead Plate filler talc 10 Fibrous filler Potassium titanate Wollastonite Total filler 5 10 15 20 15 20 30 30 30 Carbon black 1 1 1 1 1 1 1 1 1 Epoxy-containing copolymer Ethylene-glycidyl methacrylate copolymer Release agent Neopentyl erythritol tetrastearate 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total 100 100 100 100 100 100 100 100 100 Surface whitening ○ ○ × × ○ ○ × ○ ○ Ball bearing sliding wear resistance × ○ ○ ○ ○ ○ ○ ○ ○ Flexibility × ○ × ○ × × ○ ○ ○ Welding strength × × × ○ × △ ○ × × Number of dust generation Pcs/80ml 7000 15000 23000 45,000 17000 23000 36000 21000 26000

[Table 2] Example 1 Example 2 Comparative example 10 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Liquid crystal resin Liquid crystalline polyester amide 73.7 68.7 68.7 68.7 73.7 68.7 73.7 68.7 63.7 Granular filler Silica 1 Silica 2 20 20 Silica 3 5 10 15 15 20 20 15 Silica 4 Alumina glass bead Plate filler talc 5 10 25 20 10 15 5 10 20 Fibrous filler Potassium titanate Wollastonite Total filler 25 30 30 30 25 30 25 30 35 Carbon black 1 1 1 1 1 1 1 1 1 Epoxy-containing copolymer Ethylene-glycidyl methacrylate copolymer Release agent Neopentyl erythritol tetrastearate 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total 100 100 100 100 100 100 100 100 100 Surface whitening ○ ○ ○ ○ ○ ○ ○ ○ ○ Ball bearing sliding wear resistance ○ ○ × ○ ○ ○ ○ ○ ○ Flexibility △ ○ ○ ○ △ ○ △ ○ ○ Welding strength △ ○ ○ ○ ○ ○ ○ ○ ○ Number of dust generation Pcs/80ml 22000 25894 33000 35000 29000 38000 35000 34500 50000

[table 3] Comparative example 11 Comparative example 12 Comparative example 13 Example 9 Comparative example 14 Comparative example 15 Comparative example 16 Comparative example 17 Liquid crystal resin Liquid crystalline polyester amide 58.7 63.7 68.7 68.7 68.7 68.7 68.7 68.7 Granular filler Silica 1 Silica 2 Silica 3 20 25 Silica 4 5 10 10 10 10 10 Alumina 20 glass bead 20 Plate filler talc 20 10 25 20 Fibrous filler Potassium titanate 20 Wollastonite 20 Total filler 40 35 30 30 30 30 30 30 Carbon black 1 1 1 1 1 1 1 1 Epoxy-containing copolymer Ethylene-glycidyl methacrylate copolymer Release agent Neopentyl erythritol tetrastearate 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 total 100 100 100 100 100 100 100 100 Surface whitening × × ○ ○ ○ × ○ × Ball bearing sliding wear resistance ○ ○ × ○ ○ ○ ○ ○ Flexibility ○ ○ ○ ○ ○ ○ ○ ○ Welding strength ○ ○ ○ ○ × × × ○ Number of dust generation Pcs/80ml 65,000 52000 40000 45,000 28000 60000 25000 98000

[Table 4] Example 10 Example 11 Example 12 Example 13 Comparative Example 18 Example 14 Liquid crystal resin Liquid crystalline polyester amide 73.7 68.7 68.7 63.7 58.7 66.7 Granular filler Silica 1 Silica 2 Silica 3 Silica 4 15 15 20 10 15 15 Alumina glass bead Plate filler talc 10 15 10 25 25 15 Fibrous filler Potassium titanate Wollastonite Total filler 25 30 30 35 40 30 Carbon black 1 1 1 1 1 1 Epoxy-containing copolymer Ethylene-glycidyl methacrylate copolymer 2 Release agent Neopentyl erythritol tetrastearate 0.3 0.3 0.3 0.3 0.3 0.3 total 100 100 100 100 100 100 Surface whitening ○－ ○－ ○ ○ × ○－ Ball bearing sliding wear resistance ○ ○ ○ ○ ○ ○ Flexibility △ ○ ○ ○ ○ △ Welding strength ○ ○ ○ ○ ○ ○ Number of dust generation Pcs/80ml 15220 53509 59,000 56000 90000 33470

From the results described in Tables 1 to 4, it is clear that the molded body of the examples has excellent balance of suppression of surface whitening, low bendability, weld strength, and low dust generation, and reduced ball bearing sliding wear properties.

1: Test strip for measurement 2: Grease 3: arm 4: particles 10: Open hole test piece 11: Film gate 12: hole 13a, 13b: Test strip for measurement

Fig. 1 is a diagram for explaining a method of evaluating sliding wear. Fig. 2(a) is a diagram showing a camera module type molded product used for bending deformation evaluation, and Fig. 2(b) is a diagram showing a measurement place for bending deformation evaluation. Furthermore, the numerical unit in the figure is mm. Fig. 3 is a diagram showing a molded product used for evaluating weld strength. Furthermore, the numerical unit in the figure is mm.

Claims (4)

A liquid crystal resin composition for ball bearing sliding wear resistant parts, containing: (A) Liquid crystal resin; (B) Granular filler; and (C) Plate filler, The intermediate diameter of the above (B) granular filler is 1.3~5.0μm, The content of the above (B) granular filler is 7.5-22.5 mass%, The content of the above (C) platy filler is 2.5-27.5 mass%, The total content of the aforementioned (B) granular filler and the aforementioned (C) platy filler is 22.5 to 37.5% by mass. The composition according to claim 1, wherein The above (B) granular filler is silicon dioxide (silica), The above-mentioned (C) plate-shaped filler is talc. The composition according to claim 1 or 2 further contains (D) an epoxy-containing copolymer, and the content of the above-mentioned (D) epoxy-containing copolymer is 1 to 5% by mass. A ball bearing resistant sliding wear component, which is composed of the composition according to any one of claims 1 to 3.

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