Polybutylene naphthalate resin composition and molded article using same

Abstract

To provide a polybutylene naphthalate resin composition that has high bleedout resistance while expressing low frictional coefficients during sliding at a high load, and a molding including the same.SOLUTION: A resin composition contains, based on (A) a polybutylene naphthalate resin (A component) 100 pts.wt., (B) a modified ultrahigh-molecular-weight polyethylene having an intrinsic viscosity of 5-28 dl / g, measured in a decalin acid solvent at 135°C (B component) 5-30 pts.wt., (C) a carbon fiber (C component) 2-9 pts.wt. and (D) a polyolefin wax (D component) 1-15 pts.wt.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a polybutylene naphthalate resin composition that exhibits a low friction coefficient during sliding under a high load and is excellent in bleed-out resistance, and to a molded article using the same. [Background technology]

[0002] Conventionally, thermoplastic aromatic polyester resins have excellent mechanical properties, heat resistance, and chemical resistance, and are widely used for electrical and electronic parts, home appliances, and automotive parts. Among them, polybutylene naphthalate resins have excellent sliding properties and hydrolysis resistance compared to polybutylene terephthalate resins, and are therefore used for various gears and polishing pads. However, in fields where sliding properties are required under higher loads, it has been difficult to achieve a low friction coefficient while maintaining the strength of the parts.

[0003] Patent Document 1 proposes a polybutylene naphthalate resin composition having excellent sliding properties and a sliding part using the same, which is a resin composition consisting of a polybutylene naphthalate resin, a high-density polyethylene resin, and an acid-modified polyethylene resin. However, although the sliding properties under low loads are improved, the sliding properties under high loads are insufficient and further improvement is required. Patent Documents 2 and 3 propose a resin composition consisting of a synthetic resin, a fibrous filler, and an olefin wax or a paraffin wax, and an attempt is made to improve the sliding properties of the resin. However, since the wax component bleeds out from the resin part over time, there are still problems with process contamination due to component separation during molding and stabilization of sliding performance over a long period of time. Furthermore, there is insufficient knowledge about the reduction of the friction coefficient during sliding under high loads. Patent Document 4 proposes a resin composition having excellent friction and wear properties consisting of a polyester resin, an ultra-high molecular weight polyethylene, and a carbon fiber, but there is also insufficient knowledge about the reduction of the friction coefficient during sliding under high loads, and further improvement is required. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2010-111759 A [Patent Document 2] Patent No. 4209666 [Patent Document 3] Japanese Patent Application Publication No. 59-84990 [Patent Document 4] Japanese Patent Application Publication No. 63-297455 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a polybutylene naphthalate resin composition which exhibits a low friction coefficient during sliding under a high load and is excellent in bleed-out resistance, and a molded article using the same. [Means for solving the problem]

[0006] As a result of extensive research aimed at solving the above-mentioned problems, the inventors discovered that the above object could be achieved by blending polybutylene naphthalate resin with modified ultra-high molecular weight polyethylene, carbon fiber and polyolefin wax in specific ratios, which led to the present invention.

[0007] That is, the present invention provides a method for producing a decalcification film having a temperature of 135° C. with respect to 100 parts by weight of (A) polybutylene naphthalate resin (component A). Solvent The intrinsic viscosity measured in the solvent is 5 to 28 dl / g. Modified with maleic anhydride This is achieved by a resin composition comprising 5 to 30 parts by weight of modified ultra-high molecular weight polyethylene (component B), 2 to 9 parts by weight of (C) carbon fiber (component C), and 1 to 15 parts by weight of (D) polyolefin wax (component D). Effect of the Invention

[0008] According to the present invention, while exhibiting a low coefficient of friction under high loads, by appropriately suppressing the bleed-out of the sliding material, it is possible to provide a polybutylene naphthalate resin composition excellent in antifouling properties and long-term stability of sliding properties in the manufacturing process. The molded article obtained from the resin composition of the present invention can be suitably used not only for electric and electronic parts and automotive parts but also for building members that require high long-term stability of sliding properties.

Mode for Carrying Out the Invention

[0009] Hereinafter, the details of the present invention will be further described.

[0010] <Regarding Component A> The polybutylene naphthalate resin, which is Component A of the present invention, can be produced using a dicarboxylic acid component mainly composed of naphthalenedicarboxylic acid and / or an ester-forming derivative of naphthalenedicarboxylic acid, and a glycol component mainly composed of 1,4-butanediol.

[0011] The naphthalenedicarboxylic acid component is mainly composed of 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid, but other dicarboxylic acids can be used in combination as long as the properties are not impaired. Examples of other dicarboxylic acids include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid. One or more of these may be used, and can be selected arbitrarily depending on the purpose. The amount of other dicarboxylic acids used is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total acid components. The ester-forming derivatives of naphthalenedicarboxylic acid are mainly composed of dimethyl 2,6-naphthalenedicarboxylate and dimethyl 2,7-naphthalenedicarboxylate, but can be used in combination with ester-forming derivatives of other dicarboxylic acids as long as the properties are not impaired. Examples of ester-forming derivatives of other dicarboxylic acids include lower dialkyl esters of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and diphenylether-4,4'-dicarboxylic acid, lower dialkyl esters of alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and lower dialkyl esters of aliphatic dicarboxylic acids such as adipic acid, sebacic acid, succinic acid, and oxalic acid. One or more of these may be used, and can be selected arbitrarily depending on the purpose. The amount of the ester-forming derivatives of other dicarboxylic acids used is preferably 30 mol% or less, more preferably 20 mol% or less, based on the total dicarboxylic acid ester-forming derivative components.

[0012] A small amount of a trifunctional or higher dicarboxylic acid component such as trimellitic acid, an acid anhydride such as trimellitic anhydride, or a hydroxycarboxylic acid or an alkyl ester thereof such as lactic acid or glycolic acid may be used, and may be selected according to the purpose.

[0013] The glycol component is mainly 1,4-butanediol, but other glycol components can be used in combination as long as the properties are not impaired. Examples of other glycol components include ethylene glycol, 1,3-propylene glycol, and 1,2-propylene glycol. One or more of alkylene glycols such as glycerin, neopentylene glycol, hexamethylene glycol, decamethylene glycol, cyclohexanedimethanol, diethylene glycol, triethylene glycol, poly(oxy)ethylene glycol, poly(oxy)tetramethylene glycol, and poly(oxy)methylene glycol may be used, and may be selected arbitrarily depending on the purpose. A small amount of a polyhydric alcohol component such as glycerin may also be used. A small amount of an epoxy compound may also be used. The amount of other glycol components used is preferably 30 mol % or less, more preferably 20 mol % or less, based on the total glycol components.

[0014] The amount of the glycol component used is preferably 1.1 to 1.4 times by mol relative to the dicarboxylic acid or the ester-forming derivative of the dicarboxylic acid. If the amount of the glycol component used is less than 1.1 times by mol, the esterification or transesterification reaction may not proceed sufficiently, which is not preferable. Also, if the amount exceeds 1.4 times by mol, the reaction rate may slow down, although the reason is unclear, and the amount of by-products such as tetrahydrofuran generated from the excess glycol component may increase, which is not preferable.

[0015] In the production of polybutylene naphthalate resin, a titanium compound is used as a polymerization catalyst. The titanium compound used as a polymerization catalyst is preferably a tetraalkyl titanate, specifically tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate, tetra-sec-butyl titanate, tetra-t-butyl titanate, tetra-n-hexyl titanate, tetracyclohexyl titanate, tetraphenyl titanate, tetrabenzyl titanate, etc., and may be used as a mixed titanate. Among these titanium compounds, tetra-n-propyl titanate, tetraisopropyl titanate, and tetra-n-butyl titanate are particularly preferred, and tetra-n-butyl titanate is the most preferred. The amount of the titanium compound added is preferably 10 ppm or more and 60 ppm or less, more preferably 15 ppm or more and 30 ppm or less, in terms of the titanium atom content in the resulting polybutylene naphthalate resin. If the titanium atom content in the resulting polybutylene naphthalate resin exceeds 60 ppm, the color tone and thermal stability of the resin composition of the present invention may decrease, which is not preferable. On the other hand, if the titanium atom content is less than 10 ppm, good polymerization activity may not be obtained, and a polybutylene naphthalate resin with a sufficiently high intrinsic viscosity may not be obtained, which is not preferable. The polybutylene naphthalate resin of the present invention is preferably produced through an esterification or transesterification reaction step and a subsequent polycondensation reaction step of a dicarboxylic acid component mainly composed of naphthalenedicarboxylic acid and / or its ester-forming derivative and a glycol component mainly composed of 1,4-butanediol in the presence of a titanium compound, and the temperature at the end of the esterification or transesterification reaction is preferably in the range of 180°C to 220°C, more preferably 180°C to 210°C. If the temperature at the end of the esterification or transesterification reaction exceeds 220°C, the reaction rate increases, but by-products such as tetrahydrofuran may increase, which is not preferable. In addition, if the temperature is less than 180°C, the reaction may not proceed.The reaction product (bis glycol ether and / or its low polymer) obtained by the esterification or transesterification reaction is preferably polycondensed under a reduced pressure of 0.4 kPa (3 Torr) or less at a temperature not lower than the melting point of the polybutylene naphthalate resin and not higher than 270 °C. When the polycondensation reaction temperature exceeds 270 °C, the reaction rate rather decreases and the coloring becomes significant, which is not preferable.

[0016] <Regarding Component B> The modified ultra-high molecular weight polyethylene which is Component B of the present invention has an intrinsic viscosity [η] measured in decalin at 135 °C of 5 to 28 dl / g, preferably 8 to 28 dl / g, more preferably 10 to 26 dl / g. When the intrinsic viscosity of Component B is less than 5 dl / g, the slidability under high load becomes insufficient, and when it exceeds 28 dl / g, it is liable to delaminate during injection molding and the toughness decreases. The intrinsic viscosity was measured by the following method. That is, 20 mg of the sample is dissolved in 15 mL of decalin solvent, and the specific viscosity ηsp is measured in an oil bath at 135 °C. After adding 5 mL of decalin solvent to this decalin solution for dilution and then measuring the specific viscosity ηsp. This dilution operation is repeated 2 more times, and the value of ηsp / C when extrapolating the concentration (C) of the modified ultra-high molecular weight polyethylene to 0 was taken as the intrinsic viscosity [η] of the modified ultra-high molecular weight polyethylene. Examples of the modifying component used in the production of the modified ultra-high molecular weight polyethylene include maleic anhydride and itaconic anhydride, and maleic anhydride is particularly preferable. The content rate of the modifying group in the modified ultra-high molecular weight polyethylene is preferably 0.05 to 3% by weight. When the modification amount is less than 0.05% by weight, the reactivity with the polybutylene naphthalate resin is low, so delamination may easily occur and the toughness may decrease. When it exceeds 3% by weight, the reactivity may become excessively high and gelation may occur. In addition, when unmodified ultra-high molecular weight polyethylene is used, the toughness decreases.

[0017] ​​The content of Component B is 5 to 30 parts by weight, preferably 7 to 25 parts by weight, more preferably 10 to 20 parts by weight with respect to 100 parts by weight of Component A. When the content is less than 5 parts by weight, the slidability under high load is insufficient, and the bleed-out amount of the polyolefin-based wax increases. When it exceeds 30 parts by weight, delamination is likely to occur and the toughness decreases.

[0018] <Regarding Component C> As the carbon fiber used in the present invention, any carbon fiber may be used as long as it is generally referred to as carbon fiber. For example, PAN-based carbon fiber using polyacrylonitrile as a raw material, pitch-based carbon fiber using petroleum tar or petroleum pitch as a raw material, vapor-grown carbon fiber using hydrocarbons or the like as a raw material, cellulose-based carbon fiber using viscose rayon or the like as a raw material, and the like can be mentioned.

[0019] The fiber diameter of the carbon fiber is not particularly limited, but is preferably 1 to 15 μm, more preferably 2 to 13 μm. Carbon fibers having an average fiber diameter within such a range may be able to exhibit good slidability without impairing the appearance of the molded body.

[0020] Further, the carbon fiber may be subjected to a sizing treatment from the viewpoints of productivity and mechanical strength. Examples of the sizing agent include olefin-based resins, styrene-based resins, acrylic-based resins, polyester-based resins, epoxy-based resins, and urethane-based resins, but are not particularly limited. From the viewpoint of processability, the preferable amount of the sizing agent is 0 to 5% by weight, more preferably 0.1 to 4% by weight. The carbon fiber may have a metal layer coated on the surface of the carbon fiber. Examples of the metal include silver, copper, nickel, and aluminum, and nickel is preferable from the viewpoint of the corrosion resistance of the metal layer.

[0021] The content of Component C is 2 to 9 parts by weight, preferably 3 to 9 parts by weight, more preferably 4 to 8 parts by weight with respect to 100 parts by weight of Component A. When the content of Component C is less than 2 parts by weight, sufficient strength cannot be maintained under high load, and as a result, a low friction coefficient during sliding under high load is not exhibited. When it exceeds 9 parts by weight, a low friction coefficient during sliding under high load is not exhibited either.

[0022] <Regarding Component D> As the polyolefin wax used in the present invention, those known per se can be used, such as polyolefin waxes which are polymers of olefin monomers having 2 to 8 carbon atoms such as ethylene, propylene, 1-butene, 1-pentene, isobutene, isobutylene, butadiene or their thermal decomposition products, oxidized polyolefin waxes obtained by subjecting the above polyolefin waxes to a molten state at or above the melting point and introducing air or oxygen or an oxygen-containing gas thereto to introduce functional groups by an oxidation reaction, acrylic acid, methacrylic acid, vinyl acetate, propi Preferred examples of the acid-modified polyolefin wax include unsaturated carboxylic acids having 3 to 8 carbon atoms, such as vinyl phosphate, maleic acid, maleic anhydride, itaconic acid, and maleic acid monomethyl ester, and metal salts in which the acids are all or partly neutralized with monovalent or divalent metal cations, such as sodium, potassium, lithium, zinc, magnesium, and calcium, and functional group-containing monomers, such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isobutyl acrylate, isobutyl methacrylate, n-butyl acrylate, n-butyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, maleic acid monomethyl ester, glycidyl acrylate, glycidyl methacrylate, vinyl acetate, acrylamine, and acrylamide, are copolymerized, block-polymerized, or graft-polymerized. Among these, polyethylene wax, oxidized polyethylene wax, acid-modified polyethylene wax, or a mixture thereof are more preferred. As the acid-modified wax, maleic acid modification or maleic anhydride modification is particularly preferred. In addition, the oxidized wax preferably has a carboxyl group, a ketone group, and a hydroxyl group introduced therein. The polyolefin wax preferably has a viscosity average molecular weight of 1,000 or more and less than 10,000, more preferably 1,500 or more and less than 8,000. If the viscosity average molecular weight is less than 1,000, separation between the resin and the wax may occur, and the processability during molding may decrease. If the viscosity average molecular weight is 10,000 or more, the performance as a solid lubricant may not be fully exhibited, and the sliding properties may be poor.

[0023] The content of component D is 1 to 15 parts by weight, preferably 1 to 13 parts by weight, and more preferably 2 to 10 parts by weight, per 100 parts by weight of component A. If the content of component D is less than 1 part by weight, the solid lubricating effect of the wax is insufficient, resulting in insufficient sliding properties under high load, whereas if it exceeds 15 parts by weight, bleed-out resistance is poor.

[0024] In the present invention, by using modified ultra-high molecular weight polyethylene and polyolefin wax in combination in the range of 5 to 30 parts by weight of modified ultra-high molecular weight polyethylene and 1 to 15 parts by weight of polyolefin wax with respect to 100 parts by weight of Component A, it is possible to reduce the coefficient of friction under high load and suppress the amount of bleed-out from the resin composition as compared with the case of containing each alone. Although the reason for this is not clear, it is considered that the intermolecular interaction between the modified ultra-high molecular weight polyethylene and the polyolefin wax exhibits an effect of moderately suppressing the bleed-out to the outside of the matrix.

[0025] <Regarding Component E> The spherical silica used in the present invention can be a known one, and its production method is not particularly limited. Examples thereof include spherical silica produced by the vapor phase method, precipitation method, gel method, sol-gel method, and explosion combustion method (VMC method). The sphericity of the spherical silica is preferably 0.7 or more, more preferably 0.8 or more. The sphericity is calculated by measuring the projected area and the perimeter of the silica particles, and sphericity = 4π×(projected area) / (perimeter). 2 It is calculated by. The average particle diameter of the spherical silica is preferably 1 to 15 μm in diameter, more preferably 3 to 12 μm, from the viewpoints of ensuring the slidability and toughness of the molded body. The average particle diameter was measured by the following method. That is, according to JIS Z8825 and JIS Z8819-2, the volume average diameter was calculated from the particle size distribution obtained by the laser diffraction scattering method and used as the average particle diameter.

[0026] The content of Component E is preferably in the range of 1 to 15 parts by weight, more preferably 2 to 10 parts by weight, with respect to 100 parts by weight of Component A. By containing Component E within the above range, the strength of the molded body under high load can be maintained, and the contact area with the sliding mating material can be reduced by the surface uneven structure derived from the silica particles near the surface of the molded body, and a low coefficient of friction may be exhibited.

[0027] In addition, the resin composition of the present invention may contain other thermoplastic resins within a range not contrary to the gist of the present invention. In addition, various additives such as antioxidants, impact modifiers, plasticizers, inorganic fillers, non-halogen flame retardants, colorants, light stabilizers, antistatic agents, antiblocking agents, lubricants other than components B and D, dispersants, flow modifiers, and crystal nucleating agents may be included as necessary.

[0028] <Method of producing resin composition> Any method can be used to produce the resin composition of the present invention. For example, each component and optionally other components can be premixed, then melt-kneaded, and pelletized. Premixing means can include a Nauta mixer, a V-type blender, a Henschel mixer, a mechanochemical device, an extrusion mixer, and the like. In premixing, granulation can be performed using an extrusion granulator or a briquetting machine, etc. After premixing, the mixture is melt-kneaded using a melt kneader, typically a vented twin-screw extruder, and pelletized using equipment such as a pelletizer. Other examples of melt kneaders include a Banbury mixer, a kneading roll, and a thermostatic stirring vessel, but a vented twin-screw extruder is preferred. Alternatively, each component and optionally other components can be independently supplied to a melt kneader, typically a twin-screw extruder, without premixing.

[0029] <About the molded body> The molded article made of the resin composition of the present invention can be obtained by molding the pellets produced as described above. It is preferably obtained by injection molding or extrusion molding. Injection molding can be performed not only by ordinary molding methods, but also by injection compression molding, injection press molding, gas-assisted injection molding, foam molding (including a method of injecting a supercritical fluid), insert molding, in-mold coating molding, heat-insulating mold molding, rapid heating and cooling mold molding, two-color molding, multi-color molding, sandwich molding, and ultra-high speed injection molding. In addition, molding can be performed by either the cold runner method or the hot runner method. In extrusion molding, a molded article can be obtained by extruding a round bar and then cutting it into a disk shape, or by extruding a thick sheet and then punching it into a predetermined shape. EXAMPLES

[0030] The following examples are provided to illustrate the present invention, but are not intended to limit the scope of the invention. Physical properties were evaluated by the following methods.

[0031] [Evaluation of resin composition] (1) Coefficient of kinetic friction The pellets obtained by the method described below were dried at 120°C for 5 hours, and then molded into hollow cylindrical test pieces with an outer diameter of 25.6 mm, an inner diameter of 20 mm, and a height of 15 mm in accordance with the JIS K7218A method using an injection molding machine (EC130SXII-4Y, manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 280°C and a mold temperature of 120°C. The dynamic friction coefficient was measured when the test piece was slid against a test piece of similar shape made of stainless steel (SUS304) in accordance with the JIS K7218A method. The test was performed using a friction and wear tester (EFM-3-G, manufactured by Orientec Co., Ltd.) under conditions of a load of 4,000N, a sliding speed of 200mm / s, and a sliding distance of 12m. It is necessary that the dynamic friction coefficient at the sliding distance of 12m is 0.06 or less.

[0032] (2) Bleed-out resistance The pellets obtained by the method described below were compressed in a press heated to the melting point of the pellets + 5°C to obtain a sheet-like test piece. The test piece was attached to a glass plate of 1.5 mm in thickness, and then treated at 120°C for 4 hours. The test piece was then peeled off from the glass plate, and the haze of the glass plate was measured using a haze meter (HR-100, manufactured by Murakami Color Research Laboratory Co., Ltd.). The haze of the glass plate must be 0.5 or less.

[0033] (3) Toughness The pellets obtained by the method described below were dried at 120°C for 5 hours, and then molded into test pieces using an injection molding machine (Toshiba Machine Co., Ltd., EC130SXII-4Y) at a cylinder temperature of 280°C and a mold temperature of 120°C. Tensile tests were carried out in accordance with ISO527-1 and ISO527-2 to evaluate the toughness based on the tensile breaking elongation. The tensile breaking elongation must be 2% or more.

[0034] [Examples 1-8, Comparative Examples 1-10] According to the amounts of components added shown in Table 1, mixtures of components A, B, D, and E were separately fed into a twin-screw extruder from the first feed port. Such mixtures were obtained by mixing in a V-type blender. Here, the first feed port refers to the feed port at the base. Component C was fed from the second feed port using a side feeder. For extrusion, a vented twin-screw extruder with a diameter of 30 mm (TEX30α-31.5BW-2V, manufactured by Japan Steel Works, Ltd.) was used, and pellets were obtained by melt kneading at a screw rotation speed of 200 rpm, a discharge rate of 20 kg / h, and a vent vacuum of 3 kPa. The extrusion temperature was 280°C.

[0035] The following materials were used in the examples and comparative examples of the present invention.

[0036] (Component A) AI: Polybutylene naphthalate resin obtained in Production Example I <Manufacturing example I> 315.0 parts of 2,6-naphthalenedicarboxylic acid dimethyl ester, 200.0 parts of 1.4-butanediol, and 0.062 parts of tetra-n-butyl titanate were placed in an ester exchange reaction tank, and the ester exchange reaction was carried out for 150 minutes while the temperature of the ester exchange reaction tank was raised to 210°C. The reaction product obtained was then transferred to a polycondensation reaction tank to start the polycondensation reaction. The polycondensation reaction was carried out by gradually reducing the pressure in the polycondensation reaction tank from normal pressure to 0.13 kPa (1 torr) or less over 40 minutes, and at the same time raising the temperature to a predetermined reaction temperature of 260°C. Thereafter, the polycondensation reaction was carried out for 140 minutes while maintaining the polycondensation reaction temperature at 260°C and the pressure at 0.13 kPa (1 torr). When 140 minutes had passed, the polycondensation reaction was terminated, and the polybutylene naphthalate resin was extracted in the form of strands, which were then cut into chips using a cutter while being cooled with water. Next, the obtained polybutylene naphthalate resin was subjected to solid-phase polymerization for 8 hours under conditions of a temperature of 213° C. and a pressure of 0.13 kPa (1 Torr) or less to obtain a polybutylene naphthalate resin.

[0037] (B component) BI: Modified ultra-high molecular weight polyethylene obtained in Production Example II <Manufacturing example II> Decali at 135℃ Solvent The mixture was made of 80% by weight of ultra-high molecular weight polyethylene (Hi-Zex Million 630M, manufactured by Mitsui Chemicals, Inc.) with an intrinsic viscosity of 31 dl / g measured in a decalcification solvent at 135°C. Solvent 100 parts by weight of a polyethylene resin mixture containing 20% ​​by weight of polyethylene (Hi-Zex 2200J, manufactured by Prime Polymer Co., Ltd.) with an intrinsic viscosity of 2 dl / g measured in a solvent was mixed with 0.8 parts by weight of maleic anhydride and 0.07 parts by weight of an organic peroxide (Perhexin-25B, manufactured by Nippon Oil & Fats Co., Ltd.) in a Nauta mixer, and the resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder, manufactured by Isuzu Kakoki Co., Ltd.) set at 250°C to obtain a BI component. The resulting modified ultra-high molecular weight polyethylene was decalcified at 135°C. In solvent The intrinsic viscosity measured was 25 dl / g.

[0038] B-II: Ultra-high molecular weight polyethylene obtained in Production Example III <Production example III> Decali at 135℃ Solvent The intrinsic viscosity of the ultra-high molecular weight polyethylene (Mitsui Chemicals, Inc., Hi-Zex Million 630M) measured in a solvent of 31 dl / g was measured. Solvent A polyethylene resin mixture containing 70% by weight of polyethylene (Hi-Zex 2200J manufactured by Prime Polymer Co., Ltd.) with an intrinsic viscosity of 2 dl / g measured in a solvent was mixed in a Nauta mixer, and the resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder manufactured by Isuzu Kakoki Co., Ltd.) set at 250°C to obtain component B-II. The resulting ultra-high molecular weight polyethylene was decalcified at 135°C. In solvent The intrinsic viscosity measured was 11 dl / g.

[0039] B-III: Modified polyethylene obtained in Production Example IV <Manufacturing example IV> Decali at 135℃ Solvent100 parts by weight of polyethylene (Hi-Zex 2200J, manufactured by Prime Polymer Co., Ltd.) with an intrinsic viscosity of 2 dl / g measured in a solvent was mixed with 0.8 parts by weight of maleic anhydride and 0.07 parts by weight of an organic peroxide (Perhexin-25B, manufactured by Nippon Oil & Fats Co., Ltd.) in a Nauta mixer, and the resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder, manufactured by Isuzu Kakoki Co., Ltd.) set at 250°C to obtain component B-III. The resulting modified polyethylene was decalcified at 135°C. In solvent The intrinsic viscosity measured was 1.8 dl / g.

[0040] B-IV: Modified ultra-high molecular weight polyethylene obtained in Production Example V <Manufacturing example V> Decali at 135℃ Solvent 100 parts by weight of ultra-high molecular weight polyethylene (Hi-Zex Million 630M, manufactured by Mitsui Chemicals, Inc.) with an intrinsic viscosity of 31 dl / g measured in a solvent was mixed with 0.8 parts by weight of maleic anhydride and 0.07 parts by weight of an organic peroxide (Perhexin-25B, manufactured by Nippon Oil & Fats Co., Ltd.) in a Nauta mixer, and the resulting mixture was melt-kneaded in a single-screw extruder (EXT40 mm extruder, manufactured by Isuzu Kakoki Co., Ltd.) set at 250°C to obtain component B-IV. The resulting modified ultra-high molecular weight polyethylene was decalcified at 135°C. In solvent The intrinsic viscosity measured was 30 dl / g.

[0041] (C component) CI: Carbon fiber: PAN-based carbon fiber (Teijin Ltd. IM P303 (product name), fiber diameter 7 μm, cut length 3 mm, epoxy-based bundling agent) (D component) DI: Polyolefin wax: Oxidized polyethylene wax (Mitsui Chemicals, Inc., Mitsui Hiwax 310MP (product name), viscosity average molecular weight 3,000) D-II: Calcium stearate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) (E component) EI: Spherical silica (Adma Fine FE-975A (product name) manufactured by Admatechs Co., Ltd., average particle size 7 μm)

[0042] [Table 1]

[0043] <Examples 1 to 8> Since the composition was within the scope of the present invention, it exhibited a low dynamic friction coefficient under high load and was excellent in bleed-out resistance.

[0044] <Comparative Example 1> Since it does not contain component D, the dynamic friction coefficient under high load was high.

[0045] <Comparative Example 2> Since component B is unmodified ultra-high molecular weight polyethylene, the toughness was poor.

[0046] <Comparative Example 3> Since it does not contain component B, the dynamic friction coefficient under high load is high and the bleed-out resistance is poor.

[0047] <Comparative Example 4> Since the content of B component exceeded the upper limit, the toughness was poor.

[0048] <Comparative Example 5> Since component D is not a polyolefin wax, the results showed poor bleed-out resistance.

[0049] <Comparative Example 6> Since the content of C component exceeded the upper limit, the dynamic friction coefficient under high load was high.

[0050] <Comparative Example 7> Since it does not contain the C component, the coefficient of dynamic friction under high load was high.

[0051] <Comparative Example 8> Since the content of component D exceeded the upper limit, the results showed poor bleed-out resistance.

[0052] <Comparative Example 9> Since the intrinsic viscosity of component B was below the lower limit, the dynamic friction coefficient under high load was high.

[0053] <Comparative Example 10> Since the intrinsic viscosity of component B exceeded the upper limit, the toughness was poor.

Claims

1. A resin composition comprising 100 parts by weight of (A) polybutylene naphthalate resin (component A), 5 to 30 parts by weight of (B) modified ultra-high molecular weight polyethylene (component B) modified with maleic anhydride and having an intrinsic viscosity of 5 to 28 dl / g as measured in decalin solvent at 135°C, 2 to 9 parts by weight of (C) carbon fiber (component C), and 1 to 15 parts by weight of (D) polyolefin wax (component D).

2. 2. The resin composition according to claim 1, wherein component D contains at least one polyolefin wax selected from the group consisting of polyethylene wax, oxidized polyethylene wax and acid-modified polyethylene wax.

3. The resin composition according to claim 1 or 2, characterized in that it contains, relative to 100 parts by weight of component A, (E) 1 to 15 parts by weight of spherical silica particles having an average particle diameter of 1 to 15 μm, which is a volume average diameter calculated from a particle size distribution obtained by a laser diffraction scattering method in accordance with JIS Z8825 and JIS Z8819-2.

4. A molded article made of the resin composition according to any one of claims 1 to 3.

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