KR102323582B1 - Liquid crystalline resin composition for anti-ball bearing sliding wear member and ball bearing sliding wear-resistant member using same - Google Patents

Abstract

A liquid crystalline resin composition for a ball bearing sliding wear-resistant member used for manufacturing a ball bearing sliding wear-resistant member with a well-balanced surface whitening suppression, low warpage, welding strength, and low dusting property, and with reduced ball bearing sliding wear resistance, and the same Provided is a ball bearing sliding wear-resistant member.
The liquid crystalline resin composition for a ball bearing sliding wear-resistant member according to the present invention contains (A) a liquid crystalline resin, (B) a granular filler, and (C) a plate-shaped filler, and the median diameter of the (B) particulate filler is 1.3 to 5.0 μm, the content of the (B) particulate filler is 7.5 to 22.5 mass%, the content of the (C) plate-shaped filler is 2.5 to 27.5 mass%, the (B) particulate filler and the (C) plate-shaped filler The total content of is 22.5 to 37.5 mass%.

Description

Liquid crystalline resin composition for anti-ball bearing sliding wear member and ball bearing sliding wear-resistant member using same

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 same.

Liquid crystalline resins typified by liquid crystalline polyester resins have excellent mechanical strength, heat resistance, chemical resistance, electrical properties, etc. in a well-balanced manner, and have excellent dimensional stability, so they are widely used as high-performance engineering plastics. In recent years, liquid crystalline resins have come to be used in precision equipment parts by taking advantage of these characteristics.

As a component for which liquid crystalline resin is used, For example, Connectors, such as an FPC connector; sockets such as memory card sockets; Parts for camera modules, such as a lens holder; relays are available. These parts are required to be excellent in surface whitening suppression, low warpage properties, weld strength, and low dust generation, and also when two or more members are in dynamic contact. Since it is sometimes used in the form, it is also required that the sliding wear property (that is, the property prone to wear when two or more members are in dynamic contact) is reduced. For example, in Patent Document 1, for the purpose of providing a molded article comprising a liquid crystalline resin composition excellent in surface appearance and excellent in sliding properties, a liquid crystalline resin and talc having a specific volume average particle diameter are mixed in a specific ratio. The liquid crystalline resin composition containing is disclosed.

Among the above-mentioned parts, in the case of a part used in a form in which a molded body made of a liquid crystalline resin composition and a ball bearing are in dynamic contact, in particular, the ball bearing sliding wear property (that is, the property of being easily worn when in dynamic contact with the ball bearing) is reduction is required. Moreover, in patent document 2, the components for camera modules used in the form which dynamically contact with a ball bearing is described.

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

However, according to the examination of the present inventors, reduction in ball bearing sliding wear property is insufficient with the conventional liquid crystalline resin composition. The present invention has been made in order to solve the above problems, and the object thereof is to produce a ball bearing sliding wear resistance member with excellent balance in surface whitening suppression, low warpage, welding strength and low dust generation property, and at the same time reducing ball bearing sliding wear resistance It is to provide a liquid crystalline resin composition for a ball bearing sliding wear-resistant member used for this purpose, and a ball bearing sliding wear-resistant member using the same.

MEANS TO SOLVE THE PROBLEM The present inventors repeated earnest research in order to solve the said subject. As a result, by using a liquid crystalline resin composition containing a liquid crystalline resin, a particulate filler having a specific median diameter, and a plate filler, each content of the particulate filler, the plate filler, and their total within a predetermined range, the above problems can be solved It found out that it can be solved, and came to complete the present invention. More specifically, the present invention provides the following.

(1) containing (A) a liquid crystalline resin, (B) a particulate filler, and (C) a plate-shaped filler, wherein the (B) particulate filler has a median diameter of 1.3 to 5.0 µm, The content is 7.5 to 22.5 mass%, the content of the (C) plate-shaped filler is 2.5 to 27.5 mass%, and the total content of the (B) granular filler and the (C) plate-shaped filler is 22.5 to 37.5 mass%, Liquid crystalline resin composition for anti-ball bearing sliding wear members.

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

(3) The composition according to (1) or (2), further comprising (D) an epoxy group-containing copolymer, wherein the content of the (D) epoxy group-containing copolymer is 1 to 5 mass%.

(4) A ball bearing sliding wear-resistant member comprising the composition according to any one of (1) to (3).

When a ball bearing sliding wear-resistant member is manufactured using the liquid crystalline resin composition for a ball bearing sliding wear member of the present invention as a raw material, the surface whitening suppression, low warpage, welding strength, and low dusting properties are well balanced and excellent at the same time as the ball bearing sliding wear member. A ball bearing sliding wear member with reduced wear resistance can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure for demonstrating the sliding wear amount evaluation method.
In FIG. 2, Fig.2 (a) is a figure which shows the camera module type molded article used for flexural deformation evaluation, and (b) is a figure which shows the measurement location in flexural deformation evaluation. In addition, the unit of the numerical value in a figure is mm.
3 : is a figure which shows the molded article used by welding strength evaluation. In addition, the unit of the numerical value in a figure is mm.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described. However, this invention is not limited to the following embodiment.

<Liquid crystalline resin composition for anti-ball bearing sliding wear member>

The liquid crystalline resin composition for ball bearing sliding wear-resistant members of this invention contains (A) liquid crystalline resin, (B) granular filler, and (C) plate-shaped filler.

[(A) Liquid crystalline resin]

The (A) liquid crystalline resin used in the present invention refers to a melt-processable polymer having a property of forming an optically anisotropic melt phase. The properties of the anisotropic molten phase can be confirmed by a conventional polarization inspection method using orthogonal polarizers. More specifically, confirmation of an anisotropic molten phase can be performed by using a Leitz polarization microscope and observing the molten sample mounted on the Leitz hot stage at 40 times magnification in nitrogen atmosphere. When the liquid crystalline polymer applicable to the present invention is inspected between orthogonal polarizers, polarized light is normally transmitted even in a state of fusion stop, and exhibits optical anisotropy.

It does not specifically limit as a kind of liquid crystalline resin (A) as above, It is preferable that they are aromatic polyester and/or aromatic polyesteramide. Moreover, the polyester which contains aromatic polyester and/or aromatic polyesteramide partially in the same molecular chain is also in the range. (A) As the liquid crystalline resin, when dissolved in pentafluorophenol at a concentration of 0.1% by mass at 60°C, preferably at least about 2.0 dl/g, more preferably, a logarithmic viscosity of at least 2.0 to 10.0 dl/g ( IV) is preferably used.

The aromatic polyester or aromatic polyesteramide as (A) liquid crystalline resin applicable to the present invention is particularly preferably at least selected from the group consisting of aromatic hydroxycarboxylic acid, aromatic hydroxyamine, and aromatic diamine. It is an aromatic polyester or aromatic polyesteramide which has a repeating unit derived from 1 type of compound as a structural component.

More specifically,

(1) polyester mainly composed of repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and derivatives thereof;

(2) mainly (a) repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and derivatives thereof; and (b) one of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof; Polyester which consists of repeating units derived from 2 or more types;

(3) mainly (a) repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and derivatives thereof; and (b) one of aromatic dicarboxylic acids, alicyclic dicarboxylic acids, and derivatives thereof; or polyester comprising repeating units derived from two or more kinds and (c) repeating units derived from at least one kind or two or more kinds of aromatic diols, alicyclic diols, aliphatic diols, and derivatives thereof;

(4) mainly (a) repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and derivatives thereof; and (b) one or more of aromatic hydroxyamines, aromatic diamines and derivatives thereof. a polyesteramide comprising a repeating unit derived from (c) a repeating unit derived from one or two or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid, and derivatives thereof;

(5) mainly (a) repeating units derived from one or two or more of aromatic hydroxycarboxylic acids and derivatives thereof, and (b) one or more of aromatic hydroxyamines, aromatic diamines, and derivatives thereof A repeating unit derived from (c) a repeating unit derived from one or more of aromatic dicarboxylic acid, alicyclic dicarboxylic acid, and derivatives thereof, and (d) aromatic diol, alicyclic diol, or aliphatic diol; and a polyesteramide comprising a repeating unit derived from at least one or two or more of these derivatives. Moreover, a molecular weight modifier can also be used together with said structural component as needed.

Preferable examples of the specific compound constituting the (A) liquid crystalline 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, resorcin, a compound represented by the following general formula (I), and the following general Aromatic diols, such as a compound represented by Formula (II); aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and compounds represented by the following general formula (III); and aromatic amines such as p-aminophenol and p-phenylenediamine.

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

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

Preparation of the liquid crystalline resin (A) used in the present invention can be carried out by a known method using a direct polymerization method or a transesterification method from the above monomer compound (or a mixture of monomers), usually by a melt polymerization method, A solution polymerization method, a slurry polymerization method, a solid-state polymerization method, or the like, or a combination of two or more thereof is used, and a melt polymerization method or a combination of a melt polymerization method and a solid-state polymerization method is preferably used. The compounds having an ester-forming ability may be used for polymerization in the form as it is, or may be modified from a precursor to a derivative having the ester-forming ability in a pre-polymerization stage. When polymerizing these, various catalysts can be used. Representative examples include potassium acetate, magnesium acetate, stannous acetate, tetrabutyl titanate, lead acetate, sodium acetate, ammonium trioxide, and tris(2,4-pentanedionate). and metal salt catalysts such as cobalt(III), and organic compound catalysts such as N-methylimidazole and 4-dimethylaminopyridine. The amount of the catalyst to be used is generally about 0.001 to 1 mass %, particularly preferably about 0.01 to 0.2 mass %, based on the total mass of the monomer. Polymers prepared by these polymerization methods can be increased in molecular weight by solid-state polymerization in which heating is performed under reduced pressure or in an inert gas, if necessary.

The melt viscosity of (A) liquid crystalline resin obtained by the above method is not specifically limited. In general, melt viscosity at the molding temperature of ³ Pa·s or more and 500 Pa·s or less at a shear rate of 1000 sec -1 can be used. However, it is undesirable to have an excessively high viscosity because the fluidity is very deteriorated. Further, the liquid crystalline resin (A) may be a mixture of two or more liquid crystalline resins.

Liquid crystalline resin composition of this invention WHEREIN: Content of (A) liquid crystalline resin becomes like this. Preferably it is 62.5-77.5 mass % or 61.5-72.5 mass %, More preferably, it is 65-75 mass % or 63.5-72.5 mass %. %am. (A) If content of a component is in the said range, it is preferable from points, such as fluidity|liquidity and heat resistance.

[(B) granular filler]

Component (B) is a granular filler, and component (B) has a median diameter of 1.3 to 5.0 µm. If the said median diameter is 1.3 micrometers or more, the welding strength of a molded object will become high easily. When the said median diameter is 5.0 micrometers or less, the surface whitening suppression effect of a molded object becomes high easily. The said median diameter becomes like this. Preferably it is 1.5-5.0 micrometers, More preferably, it is 1.5-4.0 micrometers. In addition, in this specification, the median diameter means the volume-based median measured by the laser diffraction/scattering type particle size distribution measuring method.

Examples of the granular filler of component (B) include silicates such as silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, clay, diatomaceous earth, and wollastonite; metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; silicon carbide; silicon nitride; Boron nitride etc. are mentioned. (B) A component may be used individually by 1 type, and may be used in combination of 2 or more type. In this invention, it is more preferable to use silica as (B) component from a viewpoint of the surface whitening suppression of a molded object, the low dusting property of a molded object, and the welding strength of a molded object.

(B) Content of component is 7.5-22.5 mass % in the liquid crystalline composition of this invention. (B) When content of component is 7.5 mass % or more, the molded object with reduced ball bearing sliding wear property is easy to be obtained, and when it is 22.5 mass % or less, the surface whitening suppression effect of a molded object becomes high easily. (B) Preferred content of a component is 10-20 mass %.

[(C) Plate filler]

The liquid crystalline resin composition according to the present invention contains a plate-shaped filler. A plate-shaped filler can be used individually by 1 type or in combination of 2 or more types.

Liquid crystalline resin composition of this invention WHEREIN: Content of (C) plate-shaped filler is 2.5-27.5 mass %. (C) When content of component is 2.5 mass % or more, the low curvature property of a molded object becomes high easily. (C) When content of component is 27.5 mass % or less, the surface whitening suppression effect of a molded object and the low dusting property of a molded object become high easily. (C) Content of component becomes like this. Preferably it is 5-25 mass %.

Talc, mica, glass flakes, various metal foils, etc. are mentioned as a plate-shaped filler in this invention. The point of suppressing the curvature deformation of the molded object obtained from a liquid crystalline resin composition, without worsening the fluidity|liquidity of a liquid crystalline resin composition, a talc is preferable. It does not specifically limit about the median diameter of a plate-shaped filler, When the fluidity|liquidity of a liquid crystalline resin composition is considered, the smaller one is preferable. On the other hand, in order to make small the bending deformation of the molded object obtained from a liquid crystalline resin composition, it is necessary to maintain a fixed magnitude|size. Specifically, 1-100 micrometers is preferable, and 5-50 micrometers is more preferable.

[talc]

As the talc usable in the present invention, with respect to the total solid amount of the talc, Fe ₂ O _3, Al ₂ O _3, and the total content of CaO is is more than 2.5 mass%, Fe ₂ O ₃ and Al ₂ O ₃ It is preferable that the total content of is more than 1.0 mass % and 2.0 mass % or less, and that the content of CaO is less than 0.5 mass % at the same time. That is, the talc that can be used in the present invention _{contains at least one of Fe 2} O ₃ , Al ₂ O _{3 , and CaO in addition to SiO 2} and MgO as its main components, and each component contains within the above content range. It may be good to do

In the talc, when _{the total content of Fe 2} O ₃ , Al ₂ O ₃ , and CaO is 2.5% by mass or less, the moldability of the liquid crystalline resin composition and heat resistance of a molded article such as a connector molded from the liquid crystalline resin composition prone to worsening _{Therefore, Fe 2 O 3, Al 2} O 3, and the total content of CaO is preferably in a range from 1.0 mass% to 2.0 mass%.

In addition, the talc of, Fe ₂ O ₃ and Al ₂ O ₃ of the total talc content exceeds 1.0% by mass of it is easy to obtain. Further, in the talc, when _{the total content of Fe 2} O ₃ and Al ₂ O ₃ is 2.0 mass% or less, the moldability of the liquid crystalline resin composition and heat resistance of molded articles such as connectors molded from the liquid crystalline resin composition are deteriorated. easy to become Therefore, the total content of Fe ₂ O ₃ and Al ₂ O ₃ is preferably less than 1.7% by weight exceeds 1.0% by mass.

Moreover, in the said talc, when content of CaO is less than 0.5 mass %, the moldability of a liquid crystalline resin composition and the heat resistance of molded objects, such as a connector shape|molded from this liquid crystalline resin composition, are easy to deteriorate. Therefore, as for content of CaO, 0.01 mass % or more and 0.4 mass % or less are preferable.

It is preferable that it is 4.0-20.0 micrometers, and, as for the median diameter of the talc in this invention, from a viewpoint of prevention of bending deformation of a molded object, and maintenance of the fluidity|liquidity of a liquid crystalline resin composition, it is more preferable that it is 10-18 micrometers.

Moreover, content of the sum total of (B) component and (C)component is 22.5-37.5 mass % in the liquid crystalline resin composition of this invention, Preferably it is 25-35 mass %. When content of the said total is 22.5 mass % or more, the low curvature property of a molded object becomes high easily. When content of the said total is 37.5 mass % or less, the surface whitening suppression effect of a molded object and the low dusting property of a molded object become high easily.

[(D) Epoxy group-containing copolymer]

The liquid crystalline composition of this invention may contain (D) an epoxy group containing copolymer. (D) Epoxy group-containing copolymer can be used individually by 1 type or in combination of 2 or more types. (D) The epoxy group-containing copolymer is not particularly limited, and for example, at least one selected from the group consisting of (D1) an epoxy group-containing olefinic copolymer and (D2) an epoxy group-containing styrenic copolymer is mentioned. . (D) The epoxy group-containing copolymer contributes to reducing the ball bearing sliding wearability of the molded article obtained from the liquid crystalline resin composition of the present invention.

(D1) Examples of the epoxy group-containing olefinic copolymer include a copolymer composed of a repeating unit derived from an α -olefin and a repeating unit derived from a glycidyl ester of an α , β-unsaturated acid.

The α -olefin is not particularly limited, and examples thereof include ethylene, propylene and butene, and among these, ethylene is preferably used. The glycidyl ester of α, β -unsaturated acid is represented by the following general formula (IV). The glycidyl ester of α, β -unsaturated acid is, for example, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, etc., especially methacrylic acid Glycidyl esters are preferred.

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

The (D1) epoxy group-containing olefinic copolymer used in the present invention is acrylonitrile, acrylic acid ester, methacrylic acid ester, α -methylstyrene, anhydrous as a third component in addition to the above two components within the range not impairing the present invention. You may contain 0-48 mass parts of repeating units derived from 1 type(s) or 2 or more types of olefinic unsaturated ester, such as maleic acid, with respect to 100 mass parts of said 2 components.

The epoxy group-containing olefinic copolymer as component (D1) of the present invention can be easily prepared by a normal radical polymerization method using a monomer corresponding to each component and a radical polymerization catalyst. More specifically, normally, glycidyl ester of α -olefin and α , β -unsaturated acid is reacted in the presence or absence of a suitable solvent or chain transfer agent in the presence of a radical generator, at 500 to 4000 atmospheres, and at 100 to 300°C. It can be prepared by a method of copolymerizing under It can also be produced by mixing an α -olefin , a glycidyl ester of an α , β -unsaturated acid, and a radical generator, and performing melt-graft copolymerization in an extruder.

Examples of the epoxy group-containing styrenic copolymer (D2) include 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. About the glycidyl ester of (alpha) , ( beta ) -unsaturated acid, since it is the same as what was demonstrated in (D1) component, description is abbreviate|omitted.

Examples of the styrenes include styrene, α -methylstyrene, brominated styrene, and divinylbenzene, and styrene is preferably used.

The (D2) epoxy group-containing styrenic copolymer used in the present invention may be a multi-unit copolymer containing, as a third component, repeating units derived from one or two or more of other vinyl monomers in addition to the above two components. . What is preferable as a 3rd component is the repeating unit derived from 1 type(s) or 2 or more types of olefinic unsaturated esters, such as acrylonitrile, an acrylic acid ester, a methacrylic acid ester, and maleic anhydride. An epoxy group-containing styrenic copolymer containing 40% by 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 α , β -unsaturated acid is 2 to 20% by mass, and the content of the repeating unit derived from styrene is 80 to It is preferable that it is 98 mass %.

(D2) The epoxy group-containing styrenic copolymer can be prepared by a normal radical polymerization method using a monomer corresponding to each component and a radical polymerization catalyst. More specifically, usually, styrene and glycidyl ester of α , β -unsaturated acid are reacted in the presence or absence of a suitable solvent or chain transfer agent in the presence of a radical generator, at 500 to 4000 atmospheres, and at 100 to 300°C. It can manufacture by the method of copolymerizing. Moreover, it can manufacture also by the method of mixing styrene, the glycidyl ester of alpha , beta -unsaturated acid, and a radical generator, and carrying out melt-graft copolymerization in an extruder.

Moreover, as (D) an epoxy group containing copolymer, the (D1) epoxy group containing olefin type copolymer is preferable at a heat resistant point. When using together (D1) component and (D2) component, the ratio of these components can be suitably selected according to the characteristic requested|required.

(D) Content of an epoxy-group containing copolymer WHEREIN: In the liquid crystalline resin composition of this invention, 0-5 mass % may be sufficient, Preferably it is 1-5 mass %. (D) When content of component exists in the said range, it will be easy to obtain the molded object with reduced ball bearing sliding wear property, without impairing the fluidity|liquidity of a liquid crystalline resin composition. The more preferable content is 1.5 to 2.5% 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 generally available for use in resin coloring. Usually, (E) carbon black contains a mass formed by aggregation of primary particles, but unless a large amount of mass of 50 µm or more is significantly included, the resin composition of the present invention It is difficult to generate many boots (fine millet-like protrusions (fine irregularities) in which carbon black is aggregated) on the surface of the molded article formed by molding. When the content rate of particles having a particle size of 50 µm or more is 20 ppm or less, the effect of suppressing raising on the surface of the molded article is likely to increase. A preferable content rate is 5 ppm or less.

(E) As a compounding quantity of carbon black, in a liquid crystalline resin composition, what is necessary is just 0-5 mass %, for example, and the range of 0.5-5 mass % is preferable. If the compounding quantity of carbon black is 0.5 mass % or more, the jet-black property of the resin composition obtained is hard to fall, and it is hard to show unrest in light-shielding property. It is not uneconomical as the compounding quantity of carbon black is 5 mass % or less, and it is hard to generate|occur|produce a boot.

[(F) mold release agent]

The (F) mold release agent used as an optional component in the present invention is not particularly limited as long as it is generally available, and examples include fatty acid esters, fatty acid metal salts, fatty acid amides, low molecular weight polyolefins, and the like. , a fatty acid ester of pentaerythritol (eg, pentaerythritol tetrastearate) is preferred.

(F) As a compounding quantity of a mold release agent, in a liquid crystalline resin composition, what is necessary is just 0-3 mass %, for example, and the range of 0.1-3 mass % is preferable. When the compounding quantity of a mold release agent is 0.1 mass % or more, while the mold release property at the time of shaping|molding improves, it is easy to obtain the molded object with reduced ball bearing sliding wear property. If the compounding quantity of a mold release agent is 3 mass % or less, mold deposit (namely, it refers to the adhesion|attachment to the metal mold|die in shaping|molding. Hereinafter, "MD".) is reduced easily.

[Other Ingredients]

In the liquid crystalline resin composition of the present invention, other polymers, other fillers, generally known substances added to synthetic resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, Other components such as flame retardants, colorants such as dyes and pigments, lubricants, crystallization accelerators, and crystal nucleating agents may also be appropriately added according to the required performance. Other components may be used individually by 1 type, and may be used in combination of 2 or more type.

Other fillers refer to (B) granular fillers, (C) plate-shaped fillers, and (E) fillers other than carbon black, and examples thereof include fibrous fillers such as whiskers. However, it is preferable that the liquid crystalline resin composition of this invention does not contain a fibrous filler from a viewpoint, such as the welding strength of a molded object.

[Method for preparing liquid crystalline resin composition for anti-ball bearing sliding wear member]

The preparation method of the liquid crystalline resin composition for ball bearing sliding wear resistance members of this invention is not specifically limited. For example, by blending the components (A) to (C), and optionally at least one of the components (D) to (F) and other components, and melt-kneading them using a single screw or twin screw extruder. , a liquid crystalline resin composition for an anti-ball bearing sliding wear member is prepared.

[Liquid crystalline resin composition for anti-ball bearing sliding wear members]

The liquid crystalline resin composition of the present invention obtained as described above preferably has a melt viscosity of 90 Pa·sec or less, more preferably 80 Pa·sec or less, from the viewpoint of fluidity at the time of melting and moldability. In the present specification, as the melt viscosity, a value obtained by a measurement method conforming to ISO 11443 under the conditions of a cylinder temperature 10 to 20° C. higher than the melting point of the liquid crystalline resin and a shear rate of 1000 sec ^{-1 is adopted.}

<Anti-ball bearing sliding wear member>

Using the liquid crystalline resin composition of the present invention, a ball bearing sliding wear-resistant member is manufactured. The ball bearing sliding wear-resistant member of the present invention is excellent in a well-balanced surface whitening suppression, low warpage, welding strength, and low dusting properties, and at the same time, the ball bearing sliding wear resistance is reduced. The ball bearing sliding wear-resistant member of the present invention can be used for parts that can be in dynamic contact with the ball bearing in use, specifically, for example, a lens, which can be used in a form that can come into dynamic contact with the ball bearing It can be used for parts for camera modules, such as a holder.

[ Example ]

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples.

<Liquid crystalline resin>

액정성 폴리에스테르아미드 수지

Liquid crystalline polyesteramide resin

After putting the following raw materials into the polymerization vessel, the temperature of the reaction system was raised to 140°C, and the reaction was carried out at 140°C for 1 hour. Thereafter, the temperature was raised to 340° C. over 4.5 hours, and from there, the pressure was reduced to 10 Torr (that is, 1330 Pa) over 15 minutes, and acetic acid, excess acetic anhydride, and other low boiling fractions were discharged. out) while performing melt polymerization. After the stirring torque reached a predetermined value, nitrogen was introduced to bring the pressure from the reduced pressure state to the normal pressure state, and the polymer was discharged from the bottom of the polymerization vessel, and the strands were pelletized to obtain pellets. The obtained pellets were heat-treated at 300°C for 2 hours under a nitrogen stream to obtain the desired polymer. The obtained polymer had a melting point of 336°C and a melting viscosity of 19.0 Pa·s at 350°C. In addition, the melt viscosity of the said polymer was measured by carrying out similarly to the measuring method of melt viscosity mentioned later.

(I) 4-hydroxybenzoic acid (HBA); 1380 g (60 mol%)

(II) 2-hydroxy-6-naphthoic acid (HNA); 157 g (5 mol%)

(III) terephthalic acid (TA); 484 g (17.5 mol%)

(IV) 4,4'-dihydroxybiphenyl (BP); 388 g (12.5 mol%)

(V) 4-acetoxyaminophenol (APAP); 126 g (5 mol%)

metal catalysts (potassium acetate catalysts); 110mg

acylating agents (acetic anhydride); 1659g

<Materials other than liquid crystalline resin>

실리카 1: 아드마파인 SO-C4(㈜ 아드마텍스 제, 실리카, 중앙 직경 1.0 ㎛)

Silica 1: Admapine SO-C4 (manufactured by Admatex Co., Ltd., silica, median diameter 1.0 μm)

실리카 2: 아드마파인 SO-C5(㈜ 아드마텍스 제, 실리카, 중앙 직경 1.5 ㎛)

Silica 2: Admapine SO-C5 (manufactured by Admatex Co., Ltd., silica, median diameter 1.5 μm)

실리카 3: 아드마파인 SO-C6(㈜ 아드마텍스 제, 실리카, 중앙 직경 2.0 ㎛)

Silica 3: Admapine SO-C6 (manufactured by Admatex Co., Ltd., silica, median diameter 2.0 μm)

실리카 4: 덴카 용융 실리카 FB-5SDC(전기화학공업㈜ 제, 실리카, 중앙 직경 4.0 ㎛)

Silica 4: Denka Fused Silica FB-5SDC (manufactured by Electrochemical Industries, Ltd., silica, median diameter 4.0 μm)

알루미나: 아드마파인 AO-502(㈜ 아드마텍스 제, 알루미나, 중앙 직경 0.7 ㎛)

Alumina: Admapine AO-502 (manufactured by Admatex Co., Ltd., alumina, median diameter 0.7 μm)

글래스 비드: EGB731(포터즈·바로티니㈜ 제, 글래스 비드, 중앙 직경 20.0 ㎛)

Glass bead: EGB731 (manufactured by Porters Barottini, glass bead, median diameter 20.0 µm)

탤크: 크라운 탤크 PP(마츠무라산업㈜ 제, 탤크, 중앙 직경 14.6㎛)

Talc: Crown Talc PP (Matsumura Industrial Co., Ltd. talc, median diameter 14.6㎛)

티탄산칼륨: 티스모N-102(오츠카화학㈜ 제, 티탄산칼륨섬유, 평균 섬유경 0.3 ~ 0.6 ㎛, 평균섬유길이 10 ~ 20㎛)

Potassium titanate: Thismo N-102 (manufactured by Otsuka Chemical Co., Ltd., potassium titanate fiber, average fiber diameter 0.3 ~ 0.6 ㎛, average fiber length 10 ~ 20㎛)

규회석(wollastonite): NYGLOS 8(NYCO Materials사 제, 규산칼슘위스커(월래스토나이트), 수평균 섬유길이 136㎛, 평균 섬유경 8㎛)

wollastonite: NYGLOS 8 (NYCO Materials, calcium silicate whisker (wollastonite), number average fiber length 136㎛, average fiber diameter 8㎛)

에폭시기 함유 올레핀계 공중합체: 본드패스트 2C(스미토모화학㈜ 제, 에틸렌-글리시딜메타크릴레이트 공중합체, 글리시딜메타크릴레이트의 함유량 6질량%)

Epoxy group-containing olefinic copolymer: Bond Fast 2C (manufactured by Sumitomo Chemical Co., Ltd., ethylene-glycidyl methacrylate copolymer, glycidyl methacrylate content of 6% by mass)

카본 블랙: VULCAN XC305(캐봇재팬㈜ 제, 평균 입자경 20nm, 입자경 50㎛ 이상의 입자 비율이 20ppm 이하)

Carbon black: VULCAN XC305 (manufactured by Cabot Japan Co., Ltd., average particle size of 20 nm, particle ratio of 50 μm or more and less than 20 ppm)

이형제: 펜타에리트리톨 테트라스테아레이트(에머리오레오케미컬즈 재팬㈜ 제)

Release agent: pentaerythritol tetrastearate (manufactured by Emery Oreo Chemicals Japan)

<Production of liquid crystalline resin composition for anti-ball bearing sliding wear member>

The above components were melt-kneaded at a cylinder temperature of 350°C using a twin-screw extruder (TEX30 α type manufactured by Nippon Steel Co., Ltd.) at the ratios (unit: mass %) shown in Tables 1 to 4, and liquid crystal for ball bearing sliding wear-resistant members A resin composition pellet was obtained.

<Surface whitening>

Using a molding machine (“SE30DUZ” manufactured by Sumitomo Heavy Industries, Ltd.), the pellets of Examples and Comparative Examples were molded under the following molding conditions to obtain a measurement test piece (12.5 mm × 120 mm × 0.8 mm). The test piece for measurement was hung on the ultrasonic cleaner (output 300W, frequency 45kHz) in water (80 mL) at room temperature for 3 minutes. Then, the surface of the test piece for a measurement was observed visually. The following reference|standard evaluated the surface whitening of the test piece for a measurement. A result is shown in Tables 1-4.

○ (Good): Whitening was not recognized on the entire surface of the test piece.

○- (somewhat good): Very slight whitening was observed near the gate and/or near the ejector pin marks.

x (poor): Clear whitening was recognized in the smooth part of a test piece.

〔Molding conditions〕

Cylinder temperature: 350℃

Mold temperature: 80℃

Injection speed: 100mm/sec

<Ball bearing sliding wear>

The pellets of Examples and Comparative Examples were molded under the following molding conditions using a molding machine (“SE100DU” manufactured by Sumitomo Heavy Industries Co., Ltd.) to obtain a test piece for measurement (80 mm × 80 mm × 1 mm). Using a light load reciprocating sliding tester, as shown in Fig. 1, on the test piece 1 for measurement, with grease 2 interposed therebetween, the ball 4 (diameter) at the tip of the arm 3 5 mm, made of SUS) and subjected to a reciprocating sliding test under the following reciprocating sliding conditions, the width of the ball bearing sliding marks remaining on the test piece 1 for measurement is measured using a stereoscopic microscope, and the ball bearing sliding wear is It was evaluated based on the following criteria. A result is shown in Tables 1-4.

○ (Good): The width of the sliding mark of the ball bearing was 540 μm or less.

x (poor): The width of the ball bearing sliding mark was more than 540 µm.

〔Molding conditions〕

Cylinder temperature: 350℃

Mold temperature: 80℃

Injection speed: 33mm/sec

[Reciprocating sliding conditions]

Sliding speed: 5cm/sec

Stroke: 20mm

Load: 29.6N (weight of 3kg)

Number of round trips: 1000

Grease: Toray Dow Corning Co., Ltd., Molycoat EM-30L

<Flexibility>

The pellets of Examples and Comparative Examples were molded using a molding machine (“SE30DUZ” manufactured by Sumitomo Heavy Industries, Ltd.) under the following molding conditions, and 10.0 mm × 10.0 mm × 1.0 mm as shown in Fig. 2(a). of the camera module type molded product was obtained. The obtained camera module molded article was placed on a horizontal desk, and the height of the camera module molded article was measured by a QuickVision 404 PROCNC image measuring machine manufactured by Mitsutoyo. At this time, the height was measured at a plurality of positions indicated in black and round in FIG. 2(b), and the difference between the maximum height and the minimum height from the least squares plane was defined as bending deformation. Flexibility was evaluated on the basis of the following criteria. A result is shown in Tables 1-4.

○ (Good): The bending deformation was 0.020 mm or less.

Δ (somewhat good): The bending deformation was greater than 0.020 mm and less than or equal to 0.025 mm.

× (bad): The bending deformation was more than 0.025 mm.

〔Molding conditions〕

Cylinder temperature: 350℃

Mold temperature: 80℃

Injection speed: 100mm/sec

Packing pressure: 50 MPa

<Weld strength>

The pellets of Examples and Comparative Examples were injection molded under the following molding conditions, and as shown in FIG. 3 , a penetration test piece 10 having a film gate 11 and a hole 12 (penetrating plate 30 mm × 30 mm × 0.3 mm, hole) 7 mm in diameter). From the obtained penetration test piece 10, a part with a width of 4.5 mm on the gate side and a part with a width of 4.5 mm on the half gate side were cut out with the hole 12 interposed therebetween, and it was set as the test pieces 13a and 13b for measurement, respectively. The flexural strength of each of the measurement specimens 13a and 13b was measured under the following measurement conditions, and the value obtained by dividing the flexural strength of the measurement specimen 13b on the half gate side by the flexural strength of the measurement specimen 13a on the gate side was taken as the welding strength retention rate, Weld strength was evaluated according to the following criteria. A result is shown in Tables 1-4.

○ (Good): Weld strength retention was 55% or more.

Δ (somewhat good): Weld strength retention was 45% or more and less than 55%.

x (poor): Weld strength retention was less than 45%.

〔Molding conditions〕

Molding machine: Sumitomo Heavy Industries SE30DUZ

Cylinder temperature: 350℃-350℃-350℃-340℃-330℃

Mold temperature: 90℃

Injection speed: 200 mm/sec

Holding force: 50Mpa

Holding time: 2sec

Cooling time: 8sec

Screw rotation speed: 150rpm

Screw back pressure: 1Mpa

〔Measuring conditions〕

Measuring device: RTM-100 made by Orientec, Tenshiron universal testing machine

Load cell: 100 kg

Span: 4.8 mm

Bending speed: 2 mm/min

<Number of Dust Generation>

The pellets of Examples and Comparative Examples were molded under the following molding conditions using a molding machine (“SE30DUZ” manufactured by Sumitomo Heavy Industries Co., Ltd.) to obtain a molded body of 12.5 mm × 120 mm × 0.8 mm. This molded body was used as a test piece.

〔Molding conditions〕

Cylinder temperature: 350℃

Mold temperature: 80℃

Injection speed: 100 mm/sec

〔evaluation〕

The test piece was hung in an ultrasonic cleaner (output 300 W, frequency 45 kHz) in water (80 mL) at room temperature for 3 minutes. Thereafter, the number of particles of 2 μm or larger in the water was measured with a particle counter (manufactured by RION Co., Ltd., submerged particle counter KL-11A (PARTICLE COUNTER)), and the number of dust generation was evaluated. The results are shown in Tables 1 to 4 .

As is clear from the results shown in Tables 1 to 4, it was confirmed that the molded articles of Examples were excellent in surface whitening suppression, low warpage, weld strength, and low dusting properties in a well-balanced manner, and at the same time, ball bearing sliding wear properties were reduced.

1: test piece for measurement
2: grease
3: arm
4: Ball
10: penetration test piece
11: film gate (11)
12: hole
13a, 13b: test piece for measurement

Claims (5)

(A) a liquid crystalline resin,
(B) a particulate filler, and
(C) platy fillers
contains,
(A) the liquid crystalline resin is an aromatic polyester or aromatic polyesteramide having a repeating unit derived from aromatic hydroxycarboxylic acid as a constituent component;
(B) the median diameter of the particulate filler is 1.3 ~ 5.0㎛,
The content of the (B) particulate filler is 7.5 to 22.5 mass%,
The content of the (C) plate-shaped filler is 2.5 to 27.5 mass%,
The total content of the (B) granular filler and the (C) plate-shaped filler is 22.5 to 37.5 mass%,
A liquid crystalline resin composition for a ball bearing sliding wear-resistant member which does not contain a fibrous filler. According to claim 1,
The (B) granular filler is silica, a liquid crystalline resin composition for a ball bearing sliding wear-resistant member. According to claim 1,
The (C) plate-like filler is talc, the liquid crystalline resin composition for a ball bearing sliding wear resistance member. According to claim 1,
Further (D) containing an epoxy group-containing copolymer,
The content of the (D) epoxy group-containing copolymer is 1 to 5 mass%, the ball bearing sliding wear resistance liquid crystalline resin composition. A ball bearing sliding wear-resistant member comprising the composition according to any one of claims 1 to 4.

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