CN116490572B - Liquid crystalline resin composition for ball bearing sliding wear member and ball bearing sliding wear member using same - Google Patents

Liquid crystalline resin composition for ball bearing sliding wear member and ball bearing sliding wear member using same Download PDF

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Publication number
CN116490572B
CN116490572B CN202180063200.XA CN202180063200A CN116490572B CN 116490572 B CN116490572 B CN 116490572B CN 202180063200 A CN202180063200 A CN 202180063200A CN 116490572 B CN116490572 B CN 116490572B
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ball bearing
mass
liquid crystalline
sliding wear
crystalline resin
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CN116490572A (en
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中村真奈
郑祐政
酒井不二
长永昭宏
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Polyplastics Co Ltd
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Polyplastics Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08GMACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G69/00Macromolecular compounds obtained by reactions forming a carboxylic amide link in the main chain of the macromolecule
    • C08G69/44Polyester-amides
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00Use of inorganic substances as compounding ingredients
    • C08K3/30Sulfur-, selenium- or tellurium-containing compounds
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00Use of inorganic substances as compounding ingredients
    • C08K3/34Silicon-containing compounds
    • C08K3/36Silica
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00Compositions of unspecified macromolecular compounds
    • C08L101/12Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L63/00Compositions of epoxy resins; Compositions of derivatives of epoxy resins
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L77/00Compositions of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Compositions of derivatives of such polymers
    • C08L77/12Polyester-amides

Abstract

Providing: a liquid crystal resin composition for manufacturing a ball bearing sliding wear resistant member, which is excellent in balance among surface whitening suppression, silver streak suppression, dimensional accuracy, and low dust generation, and which has reduced ball bearing sliding wear properties and maintains impact resistance. The liquid crystal resin composition for a ball bearing sliding wear resistant member of the present invention comprises: a liquid crystalline resin (A), a granular filler A (B) having a median particle diameter of 0.3 to 2.5 [ mu ] m, and a granular filler B (C) having a median particle diameter exceeding 2.5 [ mu ] m and not more than 5.0 [ mu ] m, wherein the content of the granular filler A (B) is 2.5 to 22.5% by mass, the content of the granular filler B (C) is 2.5 to 22.5% by mass, and the total content of the granular filler B (B) and the granular filler B (C) is 12.5 to 32.5% by mass.

Description

Liquid crystalline resin composition for ball bearing sliding wear member and ball bearing sliding wear member using same
Technical Field
The present invention relates to a liquid crystal resin composition for a ball bearing sliding wear resistant member and a ball bearing sliding wear resistant member using the same.
Background
Liquid crystalline resins, such as liquid crystalline polyester resins, have excellent mechanical strength, heat resistance, chemical resistance, electrical properties, and the like, and also have excellent dimensional stability, and therefore, are widely used as high-functional engineering plastics. Recently, liquid crystalline resins have been used for precision instrument parts by taking advantage of their features.
Examples of the member using the liquid crystal resin include a connector such as an FPC connector; sockets such as a memory card socket; a component for a lens holder and other camera modules; and a relay. These members are required to have excellent surface whitening suppression, silver streak suppression, dimensional accuracy, and low dust generation, and in addition, 2 or more members are sometimes used in a dynamic contact state, so that sliding wear properties (that is, ease of wear in dynamic contact of 2 or more members) are also required to be reduced. For example, patent document 1 discloses a liquid crystal resin composition containing a liquid crystal resin and talc having a specific volume average particle diameter in a specific ratio, with a view to providing a molded article made of a liquid crystal resin composition having excellent surface appearance and excellent sliding properties. The silver streak means: the phenomenon of producing a shiny silvery streak on the surface of a molded article is one of molding defects that deteriorate the appearance of the molded article.
Among the above-mentioned members, in particular, in the case of a member used in a form in which a molded body formed of a liquid crystalline resin composition is in dynamic contact with a ball bearing, it is required to reduce sliding wear properties of the ball bearing (i.e., ease of wear upon dynamic contact with the ball bearing). In addition, when the member is impacted, there is a concern that the molded body is not easily restored when dents are easily generated in the molded body and defects are generated in dynamic contact between the molded body and the ball bearing. Accordingly, the above-mentioned members are required to have impact resistance, that is, to have a property of easily recovering even if a dent is generated by an impact. Patent document 2 describes a camera module member that is used in a state of dynamic contact with a ball bearing.
Prior art literature
Patent literature
Patent document 1: japanese patent No. 5087958
Patent document 2: specification of European patent No. 2938063
Disclosure of Invention
Problems to be solved by the invention
However, according to the studies by the present inventors, in the conventional liquid crystalline resin composition, the sliding wear of the ball bearing is reduced, but the impact resistance is rather deteriorated. The present invention has been made to solve the above problems, and an object thereof is to provide: a liquid crystal resin composition for manufacturing a ball bearing sliding wear resistant member, which is excellent in balance among surface whitening suppression, silver streak suppression, dimensional accuracy, and low dust generation, and which has reduced ball bearing sliding wear properties and maintained impact resistance.
Solution for solving the problem
The present inventors have made intensive studies to solve the above problems. The result shows that: the present invention has been completed by solving the above problems by using a liquid-crystalline resin composition containing a liquid-crystalline resin, a particulate filler a and a particulate filler B, wherein the particulate filler a has a median particle diameter in a predetermined range, the particulate filler B has a median particle diameter in another predetermined range, and the contents of the particulate filler a, the particulate filler B, and the total of these are in respective predetermined ranges. More specifically, the present invention provides the following.
(1) A liquid crystalline resin composition for a ball bearing sliding wear resistant member, comprising: a liquid crystalline resin (A), a granular filler A (B) having a median particle diameter of 0.3 μm or more and 2.5 μm or less, and a granular filler B (C) having a median particle diameter of more than 2.5 μm and 5.0 μm or less, wherein the content of the granular filler A (B) is 2.5 to 22.5% by mass, the content of the granular filler B (C) is 2.5 to 22.5% by mass, and the total content of the granular filler A (B) and the granular filler B (C) is 12.5 to 32.5% by mass.
(2) The composition according to (1), wherein,
the granular filler A (B) is 1 or more selected from the group consisting of silica and barium sulfate, and the granular filler B (C) is 1 or more selected from the group consisting of silica and barium sulfate.
(3) The composition according to (1) or (2), which further comprises (D) an epoxy group-containing copolymer, wherein the content of the epoxy group-containing copolymer (D) is 1 to 5% by mass.
(4) A ball bearing sliding wear resistant member comprising the composition of any one of (1) to (3).
ADVANTAGEOUS EFFECTS OF INVENTION
When the liquid crystal resin composition for a ball bearing sliding wear member of the present invention is used as a raw material for producing a ball bearing sliding wear member, it is possible to obtain a ball bearing sliding wear member which is excellent in balance among suppression of surface whitening, suppression of silver streaks, dimensional accuracy, and low dust generation, and which is reduced in ball bearing sliding wear and maintains impact resistance.
Drawings
Fig. 1 (a) is a plan view showing a molded body molded for measuring the depth of a recess in the embodiment, and fig. 1 (b) is a longitudinal sectional view showing a BB section part of fig. 1 (a). Unless otherwise specified, the numerical values in the drawings are in mm.
Fig. 2 (a) is a perspective view showing a コ -type liquid crystalline resin molded body used for evaluation of the camber deformation in the examples, and fig. 2 (b) is a side view showing the コ -type liquid crystalline resin molded body.
Fig. 3 is a diagram for explaining a method of evaluating the sliding wear amount.
Detailed Description
Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments.
Liquid crystalline resin composition for ball bearing sliding wear resistant member
The liquid crystal resin composition for a ball bearing sliding wear resistant member of the present invention comprises: a liquid crystalline resin (A), a granular filler A (B), and a granular filler B (C).
[ (A) liquid crystalline resin ]
The liquid crystalline resin (a) used in the present invention is a melt processable polymer having a property of forming an optically anisotropic melt phase. The properties of the anisotropic melt phase can be confirmed by a conventional polarization detection method using an orthogonal polarizer. More specifically, the confirmation of the anisotropic melt phase may be performed as follows: the molten sample placed on the Leitz hot stage was observed under a nitrogen atmosphere at a magnification of 40 times using a Leitz polarizing microscope, and this was performed. When the liquid crystalline polymer which can be used in the present invention is detected between orthogonal polarizers, polarized light is generally transmitted even in a molten state of rest, and optically anisotropic is exhibited.
The type of the liquid crystalline resin (a) is not particularly limited, but aromatic polyesters and/or aromatic polyester amides are preferable. In addition, polyesters comprising partially aromatic polyesters and/or aromatic polyester amides in the same molecular chain are also within this range. As the liquid crystalline resin (A), it is preferable to use: when dissolved in pentafluorophenol at a concentration of 0.1 mass% at 60 ℃, it is preferable to have a liquid crystalline resin having a logarithmic viscosity (i.v.) of at least about 2.0dl/G, more preferably 2.0 to 10.0 dl/G.
The aromatic polyester or aromatic polyester amide of the (a) liquid crystalline resin which can be used in the present invention is particularly preferably an aromatic polyester or aromatic polyester amide having 1 or more than 2 kinds of repeating units derived from an aromatic hydroxycarboxylic acid and its derivative as constituent components.
More specifically, the process is carried out,
(1) Polyesters mainly comprising 1 or more than 2 kinds of repeating units derived from aromatic hydroxycarboxylic acids and derivatives thereof;
(2) A polyester mainly comprising (a) 1 or more than 2 kinds of repeating units derived from an aromatic hydroxycarboxylic acid and a derivative thereof, and (b) 1 or more than 2 kinds of repeating units derived from an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, and a derivative thereof;
(3) A polyester mainly comprising (a) 1 or 2 or more repeating units derived from an aromatic hydroxycarboxylic acid and a derivative thereof, (b) 1 or 2 or more repeating units derived from an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, and a derivative thereof, and (c) at least 1 or 2 or more repeating units derived from an aromatic diol, an alicyclic diol, an aliphatic diol, and a derivative thereof;
(4) A polyester amide mainly comprising (a) 1 or 2 or more repeating units derived from an aromatic hydroxycarboxylic acid and its derivative, (b) 1 or 2 or more repeating units derived from an aromatic hydroxylamine, an aromatic diamine, and its derivative, and (c) 1 or 2 or more repeating units derived from an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, and its derivative;
(5) Mainly comprising (a) 1 or 2 or more repeating units derived from an aromatic hydroxycarboxylic acid and a derivative thereof, (b) 1 or 2 or more repeating units derived from an aromatic hydroxylamine, an aromatic diamine, and a derivative thereof, (c) 1 or 2 or more repeating units derived from an aromatic dicarboxylic acid, an alicyclic dicarboxylic acid, and a derivative thereof, and (d) a polyesteramide derived from at least 1 or 2 or more repeating units derived from an aromatic diol, an alicyclic diol, an aliphatic diol, and a derivative thereof, and the like. Further, a molecular weight regulator may be used in combination with the above components as required.
As a specific example of the compound constituting the (A) liquid crystalline resin which can be used in the present invention, 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' -dihydroxybiphenyl, hydroquinone, resorcinol, a compound represented by the following general formula (I), and a compound represented by the following general formula (II); aromatic dicarboxylic acids such as 1, 4-phenylene dicarboxylic acid, 1, 3-phenylene dicarboxylic acid, 4' -diphenyl dicarboxylic acid, 2, 6-naphthalene dicarboxylic acid, and a compound represented by the following general formula (III); aromatic amines such as p-aminophenol, p-phenylenediamine, and N-acetyl-p-aminophenol.
(X is selected from alkylene (C) 1 ~C 4 ) Alkylidene, -O-, -SO 2 -, -S-, and-CO-
(Y is selected from- (CH) 2 ) n - (n=1 to 4) and-O (CH) 2 ) n O- (n=1 to 4). )
The liquid crystalline resin (a) used in the present invention can be produced from the above-mentioned monomer compound (or mixture of monomers) by a known method such as a direct polymerization method or an ester exchange method, and usually by a melt polymerization method, a solution polymerization method, a slurry polymerization method, a solid phase polymerization method, or the like, or a combination of 2 or more of these, preferably by a melt polymerization method or a combination of a melt polymerization method and a solid phase polymerization method. The above-mentioned compounds having an ester-forming ability may be used directly for polymerization, or may be modified from a precursor to a derivative having an ester-forming ability at a stage before polymerization. In the polymerization, various catalysts can be used, and typical catalysts include metal salt catalysts such as potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, antimony trioxide, and cobalt (III) tris (2, 4-pentanedione), and organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of the catalyst to be used is usually preferably about 0.001 to 1% by mass, particularly preferably about 0.01 to 0.2% by mass, relative to the total mass of the monomers. The polymer produced by these polymerization methods can be further increased in molecular weight by a solid-phase polymerization method in which heating is performed under reduced pressure or in an inert gas, as needed.
The melt viscosity of the liquid crystalline resin (a) obtained by the above method is not particularly limited. Melt viscosity at the molding temperature at a shear rate of 1000 seconds can be generally used -1 The lower range is 3 Pa.s to 500 Pa.s. However, when the viscosity is too high, fluidity is extremely deteriorated, which is not preferable. The liquid crystal resin (a) may be a mixture of 2 or more liquid crystal resins.
In the liquid crystalline resin composition of the present invention, the content of the liquid crystalline resin (a) is preferably 67.5 to 87.5 mass% or 66.5 to 82.5 mass%, more preferably 73.5 to 80 mass% or 71.5 to 76 mass%. (A) The content of the component (A) is preferably within the above range in terms of fluidity, heat resistance and the like.
[ (B) granular filler A ]
(B) The component (A) is a granular filler (A), and the median particle diameter of the component (B) is 0.3 μm or more and 2.5 μm or less. When the median particle diameter is 0.3 μm or more, the impact resistance of the molded article can be easily maintained. When the median diameter is 2.5 μm or less, the surface whitening suppression effect of the molded article tends to be high. The median particle diameter is preferably 0.5 μm or more and 2.5 μm or less, more preferably 0.5 μm or more and 2.0 μm or less. In the present specification, the median particle diameter means: a central value of the volume basis measured by laser diffraction/scattering particle size distribution measurement. The median particle diameter of the component (B) in the liquid crystalline resin composition can be measured as follows: the component (B) remaining in the liquid crystal resin composition after ashing was measured by heating at 600℃for 2 hours by the method described above. (B) The components may be used alone or in combination of 2 or more.
Examples of the particulate filler as the component (B) include silicates such as silica, quartz powder, glass beads, glass powder, potassium aluminum silicate, and diatomaceous earth; 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; phosphates such as calcium pyrophosphate and anhydrous calcium dihydrogen phosphate; silicon carbide; silicon nitride; boron nitride, and the like. In the present invention, from the viewpoint of suppressing surface whitening of the molded article and low dust generation of the molded article, it is preferable to use 1 or more selected from the group consisting of silica and barium sulfate as the component (B), and it is more preferable to use silica.
(B) The content of the component (A) in the liquid crystal composition of the present invention is 2.5 to 22.5% by mass. (B) When the content of the component is 2.5% by mass or more, a molded article having reduced sliding wear properties of the ball bearing can be easily obtained. (B) If the content of the component (A) is 22.5% by mass or less, the silver streak suppressing effect of the molded article tends to be high. The preferable content of the component (B) is 5 to 15 mass%.
[ (C) granular filler B ]
(C) The component (B) is a granular filler (B), and the median particle diameter of the component (C) exceeds 2.5 μm and is 5.0 μm or less. If the median particle diameter exceeds 2.5. Mu.m, the silver streak suppressing effect of the molded article tends to be high. When the median particle diameter is 5.0 μm or less, the surface whitening suppression effect of the molded article and the low dust generation of the molded article are liable to be high. The median particle diameter is preferably 3.0 μm or more and 4.7 μm or less, more preferably 3.5 μm or more and 4.5 μm or less. In the present specification, the median particle diameter means: a central value of the volume basis measured by laser diffraction/scattering particle size distribution measurement. The median particle diameter of the component (C) in the liquid crystalline resin composition was measured as follows: the component (C) remaining after ashing the liquid crystalline resin composition at 600℃for 2 hours was measured by applying the above method. (C) The components may be used alone or in combination of 2 or more.
Examples of the particulate filler B as the component (C) include the same particulate fillers as those exemplified for the particulate filler a as the component (B). In the present invention, from the viewpoints of suppression of surface whitening of the molded article and low dust generation of the molded article, it is preferable to use 1 or more selected from the group consisting of silica and barium sulfate as the component (C), and it is more preferable to use silica.
(C) The content of the component (A) in the liquid crystal composition of the present invention is 2.5 to 22.5% by mass. (C) If the content of the component is 2.5 mass% or more, a molded article having reduced sliding wear properties of the ball bearing can be easily obtained. (C) If the content of the component (A) is 22.5% by mass or less, the surface whitening suppression effect of the molded article tends to be high. The preferable content of the component (C) is 5 to 15 mass%.
The total content of the component (B) and the component (C) in the liquid crystalline resin composition of the present invention is 12.5 to 32.5% by mass, preferably 20 to 26.5% by mass. If the total content is 12.5 mass% or more, the dimensional accuracy of the molded article tends to be high, and a molded article having reduced sliding wear properties of the ball bearing tends to be obtained. If the total content is 32.5 mass% or less, the dust-generating property of the molded article tends to be high, and the impact resistance of the molded article tends to be maintained.
[ (D) epoxy group-containing copolymer ]
The liquid crystalline composition of the present invention may contain (D) an epoxy group-containing copolymer. (D) The epoxy group-containing copolymer may be used singly or in combination of 2 or more. The epoxy group-containing copolymer (D) is not particularly limited, and examples thereof include at least 1 selected from the group consisting of an epoxy group-containing olefin copolymer (D1) and an epoxy group-containing styrene copolymer (D2). (D) The epoxy group-containing copolymer is advantageous in reducing the sliding wear of ball bearings of molded articles obtained from the liquid crystalline resin composition of the present invention.
Examples of the epoxy group-containing olefin copolymer (D1) 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 α -olefin is not particularly limited, and examples thereof include ethylene, propylene, butene, and the like, and among them, ethylene is preferably used. The glycidyl ester of an α, β -unsaturated acid is represented by the following general formula (IV). The glycidyl ester of an α, β -unsaturated acid is, for example, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate or the like, and glycidyl methacrylate is particularly preferred.
(D1) In the epoxy group-containing olefin copolymer, the content of the repeating unit derived from an α -olefin is preferably 87 to 98% by mass, and the content of the repeating unit derived from a glycidyl ester of an α, β -unsaturated acid is preferably 13 to 2% by mass.
The epoxy group-containing olefin copolymer (D1) used in the present invention may contain, as the 3 rd component, not only the 2 kinds of components described above, but also 1 or more than 2 kinds of repeating units derived from an olefinically unsaturated ester such as acrylonitrile, acrylic acid ester, methacrylic acid ester, α -methylstyrene, maleic anhydride, etc., in an amount of 0to 48 parts by mass relative to 100 parts by mass of the 2 kinds of components, within a range not detrimental to the present invention.
The epoxy group-containing olefin-based copolymer as the component (D1) of the present invention can be easily produced by using monomers corresponding to the respective components and a radical polymerization catalyst and according to a usual radical polymerization method. More specifically, it can be generally manufactured by the following method: the alpha-olefin is copolymerized with a glycidyl ester of an alpha, beta-unsaturated acid in the presence of a radical generator, at 500 to 4000 atmospheres, 100 to 300 ℃, in the presence or absence of a suitable solvent, chain transfer agent. In addition, the method can also be used for manufacturing the alloy wire: the alpha-olefin is mixed with a glycidyl ester of an alpha, beta-unsaturated acid and a radical generator, and melt graft copolymerized in an extruder.
Examples of the epoxy group-containing styrene-based copolymer (D2) include copolymers composed of repeating units derived from styrene-based monomers and repeating units derived from glycidyl esters of α, β -unsaturated acids. The glycidyl esters of α, β -unsaturated acids are the same as those described for the component (D1), and therefore, description thereof is omitted.
As the styrenes, styrene, α -methylstyrene, brominated styrene, divinylbenzene, and the like can be mentioned, and styrene is preferably used.
The epoxy group-containing styrenic copolymer (D2) used in the present invention may be a multipolymer containing 1 or 2 or more kinds of repeating units derived from other vinyl monomers as the 3 rd component in addition to the above 2 components. The 3 rd component is preferably a repeating unit derived from 1 or 2 or more kinds of olefinically unsaturated esters such as acrylonitrile, acrylic acid ester, methacrylic acid ester, maleic anhydride and the like. An epoxy group-containing styrene copolymer containing 40 mass% or less of these repeating units in the copolymer is preferable as the component (D2).
(D2) In the epoxy group-containing styrenic copolymer, the content of the repeating unit derived from the glycidyl ester of an α, β -unsaturated acid is preferably 2 to 20% by mass, and the content of the repeating unit derived from the styrenic is preferably 80 to 98% by mass.
(D2) The epoxy group-containing styrenic copolymer can be prepared according to a usual radical polymerization method by using a monomer corresponding to each component and a radical polymerization catalyst. More specifically, it can be generally manufactured by the following method: the glycidyl esters of styrene and alpha, beta-unsaturated acids are copolymerized in the presence of a free radical generator at 500 to 4000 atmospheres and 100 to 300 ℃ in the presence or absence of a suitable solvent, chain transfer agent. In addition, the method can also be used for manufacturing the alloy wire: styrene is mixed with glycidyl esters of alpha, beta-unsaturated acids and free radical generators and melt graft copolymerized in an extruder.
The epoxy group-containing copolymer (D) is preferably an epoxy group-containing olefin copolymer (D1) in terms of heat resistance. In the case of using the component (D1) and the component (D2) in combination, the ratio of these components to each other can be appropriately selected according to the desired characteristics.
(D) The content of the epoxy group-containing copolymer in the liquid crystalline resin composition of the present invention may be, for example, 0to 5% by mass, and preferably 1 to 5% by mass. (D) If the content of the component is within the above range, a molded article having reduced sliding wear properties of the ball bearing without impairing the fluidity of the liquid crystalline resin composition can be easily obtained. More preferably, the content is 2 to 4% by mass.
[ (E) carbon black ]
The carbon black (E) used as an optional component in the present invention is not particularly limited as long as it is a generally available one used for coloring resins. Generally, the carbon black (E) contains a lump of primary particles, but if the lump is not significantly contained with a size of 50 μm or more, a large amount of coarse particles (fine coarse protrusions (fine irregularities) of the carbon black) are not easily generated on the surface of the molded article obtained by molding the resin composition of the present invention. If the content of the particles having a particle diameter of 50 μm or more is 20ppm or less, the fuzzing inhibition effect on the surface of the molded article tends to be high. The preferable content is 5ppm or less. (E) The components may be used alone or in combination of 2 or more.
The amount of the carbon black to be blended in the liquid crystalline resin composition may be, for example, in the range of 0to 5% by mass, preferably 0.5 to 5% by mass. If the amount of carbon black is 0.5 mass% or more, the black paint property of the obtained resin composition is not easily lowered, and the light-shielding property is not easily unstable. If the compounding amount of carbon black is 5 mass% or less, it is not easy to become uneconomical and coarse matters are not easy to be generated.
[ (F) Release agent ]
The release agent (F) used as an optional component in the present invention is not particularly limited as long as it is usually available, and examples thereof include fatty acid esters, fatty acid metal salts, fatty acid amides, low molecular weight polyolefin, and the like, preferably fatty acid esters of pentaerythritol (for example, pentaerythritol tetrastearate). (F) The components may be used alone or in combination of 2 or more.
The amount of the release agent (F) to be blended may be, for example, 0to 3% by mass, preferably 0.1 to 3% by mass, in the liquid crystal resin composition. If the amount of the release agent is 0.1 mass% or more, the releasability at the time of molding is improved, and a molded article having reduced sliding wear properties of the ball bearing can be easily obtained. If the compounding amount of the mold release agent is 3 mass% or less, the mold deposit (i.e., referred to as deposit on a mold during molding, hereinafter also referred to as "MD") tends to be reduced.
[ other Components ]
The liquid crystal resin composition of the present invention may be added as appropriate according to the desired properties within a range that does not hinder the effects of the present invention: other polymers, other fillers, and known substances generally added to synthetic resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants, colorants such as dyes and pigments, lubricants, crystallization accelerators, and other components such as crystallization nucleating agents. The other components may be used alone or in combination of 1 or more than 2.
The other filler is a filler other than the (B) granular filler a, (C) granular filler B, and (E) carbon black, and examples thereof include a granular filler other than the (B) component and the (C) component; a plate-like filler; fibrous filler. The other fillers may be used alone or in combination of 2 or more. Examples of the particulate filler other than the component (B) and the component (C) include particulate fillers having a median particle diameter of less than 0.3 μm or more than 5.0. Mu.m. Examples of the plate-like filler include mica and talc. Examples of the fibrous filler include glass fibers and whiskers. However, from the viewpoint of impact resistance and the like of the molded article, the liquid crystalline resin composition of the present invention preferably does not contain a plate-like filler. In addition, the liquid crystalline resin composition of the present invention preferably does not contain a fibrous filler from the viewpoints of impact resistance of the molded article, low dust generation of the molded article, and the like.
[ method for producing liquid crystalline resin composition for ball bearing sliding wear Member ]
The method for producing the liquid crystal resin composition for a ball bearing sliding wear member of the present invention is not particularly limited. For example, the liquid crystal resin composition for a ball bearing sliding wear resistant member is prepared by mixing the components (a) to (C) and at least 1 of any of the components (D) to (F) and other components, and melt-kneading them with a single screw or twin screw extruder.
[ liquid Crystal resin composition for sliding wear Member of ball bearing ]
The liquid crystal resin composition of the present invention obtained as described above preferably has a melt viscosity of 90pa·s or less, more preferably 80pa·s or less, from the viewpoints of fluidity at the time of melting and moldability. In the present specification, as the melt viscosity, the following are used: at a barrel temperature of 10to 20 ℃ higher than the melting point of the liquid crystalline resin and a shearing speed of 1000 seconds -1 Using the values obtained according to the measurement method of ISO 11443.
Ball bearing sliding wear resistant component
The liquid crystalline resin composition of the present invention is used to produce a ball bearing sliding wear resistant member. The ball bearing sliding wear resistant member of the present invention is excellent in balance among suppression of surface whitening, suppression of silver streaks, dimensional accuracy, and low dust generation, while reducing the ball bearing sliding wear properties and maintaining impact resistance. The ball bearing sliding wear resistant member of the present invention can be used for a component that is in dynamic contact with a ball bearing at the time of use, specifically, for example, a component for a camera module such as a lens holder that is used in a state of dynamic contact with a ball bearing.
Examples
The present invention will be described in further detail with reference to examples, but the present invention is not limited to these examples.
< liquid crystalline resin >)
Liquid crystalline polyester amide resin
After the following raw materials were charged into the polymerization vessel, the temperature of the reaction system was raised to 140℃and reacted at 140℃for 1 hour. Thereafter, the temperature was further raised to 340℃over 4.5 hours, and then reduced to 10Torr (i.e., 1330 Pa) over 15 minutes, and melt polymerization was carried out while distilling off acetic acid, excess acetic anhydride, and other low boiling fractions. After the stirring torque reached a predetermined value, nitrogen gas was introduced and the pressure was increased from a reduced pressure state to a pressurized state, and the polymer was discharged from the lower part of the polymerization vessel and the strand was pelletized to obtain pellets. The obtained pellets were subjected to heat treatment at 300℃for 2 hours under a nitrogen gas stream to obtain a target polymer. The melting point of the obtained polymer was 336℃and the melt viscosity at 350℃was 19.0 Pa.S. The melting point and the melt viscosity of the polymer are measured by a method for measuring the melting point and a method for measuring the melt viscosity, respectively, described later.
(I) 4-hydroxybenzoic acid (HBA); 1380g (60 mol%)
(II) 2-hydroxy-6-naphthoic acid (HNA); 157g (5 mol%)
(III) 1, 4-phenylene dicarboxylic acid (TA); 484g (17.5 mol%)
(IV) 4,4' -dihydroxybiphenyl (BP); 388g (12.5 mole%)
(V) N-acetyl-para-aminophenol (APAP); 126g (5 mol%)
Metal catalysts (potassium acetate catalysts); 110mg
Acylating agents (acetic anhydride); 1659g
< materials other than liquid crystalline resin >)
Silica A1: admafine SO-C2 (Admatechs Co., ltd., silica, median particle size 0.5 μm)
Silica A2: admafine SO-C6 (Admatechs Co., ltd., silica, median particle size 2.0 μm)
Silica B: denka fused silica FB-5SDC (manufactured by Denka Corporation, silica, median particle size 4.0 μm)
Barium sulfate a: barium sulfate (median particle size 0.6 μm, made by Sakai chemical industry Co., ltd.)
Glass beads: EGB731 (PotterSBallotini CO., ltd., median particle diameter 20.0 μm)
Mica: AB-25S (YAMAGUCHI MICA CO., LTD. Manufactured by Miq. MICA, median particle size 25.0 μm)
Talc: CROWN TALC PP (Talcum, median particle size 14.6 μm, manufactured by Songcun industries Co., ltd.)
Glass fiber: ECS03T-786H (manufactured by Nitro Kabushiki Kaisha, japan, chopped strands, fiber diameter 10 μm, length 3 mm)
Epoxy group-containing olefin copolymer: bond First 2C (ethylene-glycidyl methacrylate copolymer, 6% by mass of glycidyl methacrylate, manufactured by Sumitomo chemical Co., ltd.)
Carbon black: VULCAN XC305 (Cabot Japan CO., ltd., median particle diameter 20nm, proportion of particles having particle diameter of 50 μm or more is 20ppm or less)
Mold release agent: pentaerythritol tetrastearate (Emery Oreo Chemicals Japan CO., ltd.)
[ method of measuring melting Point ]
After the liquid crystalline resin was heated from room temperature to an endothermic peak temperature (Tm 1) observed at a temperature rise condition of 20 ℃/min by DSC manufactured by TA Instruments, the liquid crystalline resin was kept at a temperature of (Tm1+40) ℃for 2 minutes, and then was cooled to room temperature at a temperature drop condition of 20 ℃/min, and then the temperature of the endothermic peak observed at a temperature rise condition of 20 ℃/min was measured.
[ method of measuring melt viscosity ]
The melt viscosity of the liquid crystalline resin was measured at a shearing rate of 1000/sec using a capillary rheometer type 1B manufactured by Toyo Seiki Seisakusho Co., ltd at a temperature of 10to 20℃higher than the melting point of the liquid crystalline resin by using an orifice having an inner diameter of 1mm and a length of 20mm, and according to ISO 11443. The specific measurement temperature was 350 ℃.
Production of liquid Crystal resin composition for ball bearing sliding wear Member
The above components were melt-kneaded at a barrel temperature of 350℃in a twin-screw extruder (TEX 30. Alpha. Manufactured by Japanese Steel Co., ltd.) at the proportions shown in Table 1 or Table 2 to obtain pellets of the liquid crystal resin composition for ball bearing sliding wear members.
< surface whitening >)
The pellets of examples and comparative examples were molded under the following molding conditions using a molding machine (Sumitomo heavy machinery Co., ltd. "SE30 DUZ"), to obtain test pieces (12.5 mm. Times.120 mm. Times.0.8 mm). The test piece for measurement was applied to an ultrasonic cleaner (power 300W, frequency 45 kHz) in water (80 ml) at room temperature for 3 minutes. Then, the surface of the test piece for measurement was visually observed. The surface whitening of the test piece for measurement was evaluated on the basis of the following criteria. The results are shown in tables 1 and 2.
O (good): whitening was not observed over the entire surface of the test piece.
X (bad): obvious whitening was confirmed in the smooth portion of the test piece
[ Molding conditions ]
Barrel temperature: 350 DEG C
Mold temperature: 80 DEG C
Injection rate: 100 mm/sec
< silver streak >
The pellets of examples and comparative examples were molded under the following molding conditions using a molding machine (Sumitomo heavy machinery Co., ltd. "SE30 DUZ"), to obtain test pieces (30 mm. Times.30 mm. Times.0.3 mm). The surface of the test piece for measurement was visually observed. The test piece for measurement was evaluated for silver streaks based on the following criteria. The results are shown in tables 1 and 2.
O (good): of the 10 test pieces, the number of test pieces having silver streaks was 3 or more.
X (bad): of the 10 test pieces, the number of test pieces having silver streaks was more than 3.
[ Molding conditions ]
Barrel temperature: 350 DEG C
Mold temperature: 80 DEG C
Injection rate: 100 mm/sec
Ball bearing sliding wear Property
The pellets of examples and comparative examples were molded under the following molding conditions using a molding machine (SE 100DU manufactured by sumitomo heavy machinery industries, ltd.) to obtain test pieces (80 mm×80mm×1 mm). With a light load reciprocating tester, as shown in fig. 3, a ball 4 (diameter 5mm, SUS) at the tip of an arm 3 was loaded with grease 2 on a test piece 1 for measurement, and after the reciprocating sliding test was performed under the following reciprocating sliding conditions, the width of the ball bearing sliding mark remaining on the test piece 1 for measurement was measured with a solid microscope, and the ball bearing sliding wear was evaluated on the following basis. The results are shown in tables 1 and 2.
O (good): the width of the ball bearing sliding mark is less than 540 μm.
X (bad): the width of the ball bearing sliding trace exceeds 540 μm.
[ Molding conditions ]
Barrel temperature: 350 DEG C
Mold temperature: 80 DEG C
Injection rate: 33 mm/sec
[ reciprocating sliding conditions ]
Sliding speed: 5 cm/sec
Stroke: 20mm of
Load: 29.6N (3 kg heavy)
Number of reciprocations: 1000 times
And (3) lubricating grease: DOW CORNING TORAY CO., LTD. Monostaro EM-30L
< depth of recess >
Injection molding the liquid crystalline resin composition under the following molding conditions(gate: pin gate, gate size:) The molded article shown in fig. 1 (a) and 1 (b) was obtained.
[ Molding conditions ]
And (3) a forming machine: sumitomo heavy machinery industries Co., ltd., SE30DUZ
Barrel temperature: 350 DEG C
Mold temperature: 90 DEG C
Injection rate: 200 mm/sec
The depth of the recess remaining in the molded article was measured by a laser microscope after dropping the weight from the top surface of the molded article using a Dupont drop impact tester (manufactured by the company An Tian refiner) under the following conditions. The depth of the recess was used as an index indicating the impact resistance of the molded article. The impact resistance of the molded article was evaluated on the basis of the following criteria. The results are shown in tables 1 and 2.
O (good): the depth of the recess is 40 μm or less.
X (bad): the depth of the recess exceeds 40 μm.
[ test conditions ]
Drop height: 15mm of
Dropping the heavy hammer: 75g
Shooting type: diameter of 0.75mm
< evaluation of inward-tilting deformation >)
The liquid crystalline resin composition was injection molded under the following molding conditions to obtain コ -shaped liquid crystalline resin molded articles (thickness: 0.5 mm) shown in fig. 2 (a) and 2 (B), and the angle a (gate side) and the angle B (back gate side) shown in fig. 2 (B) were measured using a Keyence Corporation image size measuring apparatus IM-6020. The average of the angles a and B is calculated and used as an index indicating the dimensional accuracy of the molded article. The dimensional accuracy of the molded article was evaluated on the basis of the following criteria. The results are shown in tables 1 and 2.
O (good): the average of the angle A and the angle B is more than 87.5 degrees.
X (bad): the average of angles a and B is less than 87.5 °.
[ Molding conditions ]
And (3) a forming machine: sumitomo heavy machinery industry, SE30DUZ
Barrel temperature: 350 DEG C
Mold temperature: 90 DEG C
Injection rate: 100 mm/sec
< dust Generation count >)
The pellets of examples and comparative examples were molded by a molding machine (product of Sumitomo heavy machinery Co., ltd. "SE30 DUZ") under the following molding conditions to obtain molded articles of 12.5 mm. Times.120 mm. Times.0.8 mm. The molded article was used as a test piece.
[ Molding conditions ]
Barrel temperature: 350 DEG C
Mold temperature: 80 DEG C
Injection rate: 100 mm/sec
[ evaluation ]
The test piece was applied to an ultrasonic cleaner (power 300W, frequency 45 kHz) in water (80 ml) at room temperature for 3 minutes. Thereafter, the number of particles of 2 μm or more present in the water was measured by a Particle Counter (liquid Particle Counter KL-11A (PARTICLECOUNTER) manufactured by RION Co., ltd.) and evaluated as a dust generation number based on the following criteria. The results are shown in tables 1 and 2.
O (good): the dust generation number is 60000/80 ml or less.
X (bad): dust generation number exceeds 60000/80 ml.
TABLE 1
TABLE 2
From the results shown in tables 1 and 2, it was confirmed that the molded articles of examples were excellent in balance among suppression of surface whitening, suppression of silver streaks, dimensional accuracy, and low dust generation, and reduced in sliding wear of the ball bearings, while maintaining impact properties.

Claims (3)

1. A liquid crystalline resin composition for a ball bearing sliding wear resistant member, comprising:
(A) A liquid crystalline resin,
(B) Granular filler A
(C) A particulate filler B which is present in the form of a powder,
the liquid crystalline resin (A) is aromatic polyester and/or aromatic polyester amide,
the granular filler A is 1 or more selected from the group consisting of silica and barium sulfate,
the granular filler B is 1 or more selected from the group consisting of silica and barium sulfate,
the median particle diameter of the granular filler A of the above (B) is 0.3 μm or more and 2.5 μm or less,
the median particle diameter of the granular filler B (C) exceeds 2.5 μm and is 5.0 μm or less,
the content of the liquid crystalline resin (A) is 66.5 to 87.5 mass%,
the content of the granular filler A is 2.5 to 22.5 mass%,
the content of the granular filler B (C) is 2.5 to 22.5 mass%,
the total content of the (B) granular filler A and the (C) granular filler B is 12.5 to 32.5 mass%.
2. The composition of claim 1, further comprising (D) an epoxy-containing copolymer,
the content of the liquid crystalline resin (A) is 66.5-82.5 mass%,
the content of the epoxy group-containing copolymer (D) is 1 to 5% by mass.
3. A ball bearing sliding wear resistant member comprising the composition of claim 1 or 2.
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