TW202116899A - Polyamide resin composition for sliding components, and sliding component - Google Patents

Abstract

The purpose of the present invention is to provide a polyamide resin composition which can be used suitable for the molding of a sliding component for which excellent moldability, stability of heat resistance and toughness and excellent wear resistance and sliding stability are required. A polyamide resin composition for sliding components of the present invention comprises a crystalline polyamide resin (A), a modified polyolefin resin (B) having a reactive functional group capable of reacting with a terminal group and/or a main-chain amide group in the polyamide resin (A) and/or a thermoplastic elastomer (C) having a reactive functional group capable of reacting with a terminal group and/or a main-chain amide group in the polyamide resin (A), an antioxidant agent (D), a mold release agent (E) and a solid lubricant agent (F), wherein the modified polyolefin resin (B) and/or the thermoplastic elastomer (C) is dispersed in the form of domains having a particle diameter of 5 [mu]m or less in a matrix of the polyamide resin (A).

Description

Polyamide resin composition for sliding parts and sliding parts

The present invention relates to a polyamide resin composition, and more specifically, relates to a polyamide resin composition suitable for molding sliding parts.

Polyamide resin is a molding material with excellent sliding properties because of its crystallinity. In order to obtain better sliding properties, it is known to blend solid lubricants such as molybdenum disulfide, graphite and fluororesin, various lubricants, or liquids such as silicone oil. Lubricants, etc.

Among these sliding modifiers, solid lubricants need to be blended in a large amount, which has the disadvantage of significantly lowering the toughness of the base polyamide resin. Although the liquid lubricant can impart high sliding properties in a relatively small amount, in most cases, it has poor compatibility with the base polyamide resin, and the surface of the molded product is easily covered by the liquid lubricant. The disadvantage of pollution and limited use.

As for the method of improving the disadvantages caused by the blending of such various lubricating agents, a method of blending a modified styrene-based polymer with a modified high-density polyethylene of a specific range of molecular weight has been proposed (Patent Document 1) , In addition to using high-viscosity crystalline polyamide resin, a method of blending modified polyolefin resin, etc. (Patent Document 2).

With such polyamide resin composition, it is possible to provide molded products that do not have the above-mentioned shortcomings and have excellent sliding properties. However, in recent years, due to the trend of weight reduction of molded products and complicated shapes of molded products, it is required Improved formability, improved heat stability, and improved sliding properties, and other higher-level characteristics. [Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 8-157714 [Patent Document 2] WO2008/075699 Publication

[Problems to be solved by the invention]

The object of the present invention is to provide a polyamide resin composition that has excellent moldability, heat stability and toughness, and is suitable for the molding of sliding parts that require excellent wear resistance and sliding stability. [Means to solve the problem]

The inventors of the present case have conducted in-depth research in order to achieve the above problems and found that the addition of antioxidants and mold release agents to improve moldability and heat resistance can improve the sliding properties. Furthermore, by adding a solid lubricant to the polyamide The resin composition maintains toughness and improves sliding properties, which is the invention.

That is, the present invention has the following configuration. [1] A polyamide resin composition for sliding parts, containing a crystalline polyamide resin (A), and a reactive functional group capable of reacting with the terminal group and/or main chain amide group of the polyamide resin (A) The modified polyolefin resin (B) and/or the thermoplastic elastomer (C) with reactive functional groups that can react with the end groups and/or main chain amide groups of the polyamide resin (A), antioxidants (D), release agent (E), and solid lubricant (F); The modified polyolefin resin (B) and/or the thermoplastic elastomer (C) are dispersed in the matrix of the polyamide resin (A) in micro-domains with a particle size of 5 μm or less. [2] For example, the polyamide resin composition for sliding parts of [1], wherein the antioxidant (D) and the release agent (E) inhibit the modified polyolefin resin (B) and the thermoplastic elastomer (C) A compound that has the inactivation of the reactive functional group. [3] The polyamide resin composition for sliding parts such as [1] or [2], wherein the reactive functional group is an acid anhydride group. [4] For example, the polyamide resin composition for sliding parts in any one of [1] to [3], wherein the antioxidant (D) is a hindered phenol-based antioxidant. [5] The polyamide resin composition for sliding parts according to any one of [1] to [4], wherein the release agent (E) is a higher fatty acid ester compound. [6] The polyamide resin composition for sliding parts according to any one of [1] to [5], wherein the thermoplastic elastomer (C) is a styrene-based and/or olefin-based thermoplastic elastomer. [7] For example, the polyamide resin composition for sliding parts in any one of [1] to [6], wherein the solid lubricant (F) is a fluorine-based lubricant and/or acrylic modified polyorganosiloxane. [8] A sliding part is obtained from the polyamide resin composition for sliding parts as in any one of [1] to [7]. [Effects of Invention]

The polyamide resin composition of the present invention is not only excellent in moldability, heat stability, and toughness, but also has improved abrasion resistance, and has further improved sliding properties such as less change in friction coefficient. In addition, the polyamide resin composition of the present invention can have both low abrasion properties and low friction properties.

Hereinafter, the present invention will be specifically explained. The polyamide resin composition for sliding parts of the present invention contains a crystalline polyamide resin (A), and has a reactive function capable of reacting with the terminal group of the polyamide resin (A) and/or the main chain amide group Base modified polyolefin resin (B) (hereinafter, also referred to as modified polyolefin resin (B).) and/or has a terminal group and/or main chain amide capable of interacting with the above-mentioned polyamide resin (A) The thermoplastic elastomer (C) (hereinafter also referred to as the thermoplastic elastomer (C).) of the reactive functional group of the reaction, the antioxidant (D), the release agent (E) and the solid lubricant (F).

The blending amount of each component is such that the total of all resin components of the crystalline polyamide resin (A), modified polyolefin resin (B), thermoplastic elastomer (C) and solid lubricant (F) is 100 mass It is expressed in parts by mass. In the polyamide resin composition of the present invention, the blending amount is the content in the polyamide resin composition as it is.

The crystalline polyamide resin (A) is not particularly limited as long as it is a crystalline polymer having an amide bond (-NHCO-) in the main chain. Examples include polyamide 6 (NY6) and polyamide 66 (NY66), polyamide 46 (NY46), polyamide 11 (NY11), polyamide 12 (NY12), polyamide 610 (NY610), polyamide 612 (NY612), polyhexamide Xylylenediamine (MXD6), hexamethylenediamine-terephthalic acid polymer (6T), hexamethylenediamine-terephthalic acid and adipic acid polymer (66T), hexamethylene Diamine-terephthalic acid and ε-caprolactam copolymer (6T/6), trimethylhexamethylenediamine-terephthalic acid polymer (TMD-T), metaxylylenediamine and Adipic acid and isophthalic acid copolymer (MXD-6/I), trihexamethylene diamine and terephthalic acid and ε-caprolactam copolymer (TMD-T/6), diamino group Dicyclohexylmethane (CA), isophthalic acid and lauryl amine copolymers, etc. One kind of these may be used, or two or more kinds may be blended and used. Among these, polyamide 6 (NY6) and polyamide 66 (NY66) are preferably used.

The relative viscosity of the crystalline polyamide resin (A) is not particularly limited. It is measured with a 96% sulfuric acid solution (polyamide resin concentration 1g/dl, temperature 25°C), preferably 2.0～5.0, more preferably 2.0～ 3.5.

Modified polyolefin resin (B) is obtained by modifying polyolefin resin. As for polyolefin resins, for example, high-density polyethylene, low-density polyethylene, ultra-high molecular weight polyethylene, linear low-density polyethylene, polypropylene, poly(1-butene), poly(4-methyl) Base pentene) and so on. One kind of these may be used, or two or more kinds may be blended and used. Among these, high-density polyethylene is suitable.

In the modified polyolefin resin (B), in order to improve the compatibility with the crystalline polyamide resin (A), it has terminal groups (amine groups or carboxyl groups) and/or that can be compatible with the above-mentioned polyamide resin (A) The reactive functional group of the main chain amide group. The reactive functional group includes, for example, a carboxyl group, an acid anhydride group, an epoxy group, an oxazoline group, an amino group, an isocyanate group, and the like. Among these, considering the high reactivity with the polyamide resin (A), an acid anhydride group is preferable.

The content of the reactive functional group is preferably 0.05-8% by mass in the modified polyolefin resin (B), more preferably 0.1-5% by mass. The method for producing the above-mentioned modified polyolefin resin (B) having a reactive functional group is not particularly limited. Examples include a method of reacting a compound having the above-mentioned reactive functional group in the step of producing a polyolefin resin, and A method of mixing resin pellets with a compound having the above-mentioned reactive functional group, etc., and kneading with an extruder or the like to make it react.

The blending amount of the modified polyolefin resin (B) is not particularly limited as long as the modified polyolefin resin (B) can be dispersed in the matrix of the polyamide resin (A) in micro-domains with a particle diameter of 5 μm or less. The limit is usually 0.5-10% by mass relative to 100% by mass of all resin components, preferably 1-8% by mass, and more preferably 2-6% by mass.

The thermoplastic elastomer (C) is not particularly limited, and examples include styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, polyester-based thermoplastic elastomers, and polyurethane-based thermoplastics. Elastomers, etc. One type of these may be used, or two or more types may be blended and used.

The styrene-based thermoplastic elastomer system is not particularly limited. For example, styrene/butadiene/styrene block copolymer (SBS), and its hydrogenated styrene/ethylene-butene/styrene block copolymer (SEBS) styrene/butadiene copolymer (SBR), its hydrogenated styrene/ethylene/butylene copolymer (HSBR), styrene/isobutylene/styrene block copolymer (SIS), its Hydrogenated styrene/ethylene-propylene/styrene block copolymer (SEPS), etc.

The olefin-based thermoplastic elastomer system is not particularly limited. Examples include rubbers such as ethylene/propylene/diene rubber (EPDM), ethylene/propylene rubber (EPR), butyl rubber (IIR), and dynamically crosslinked olefin-based thermoplastic elastomers. Body, flexible ethylene copolymer, etc.

The polyamide-based thermoplastic elastomer system is not particularly limited. For example, a polyetherester having a crystalline and high melting temperature polyamide as a hard segment and a polyether or polyester with a low glass transition temperature as a soft segment can be mentioned. Amide and polyester amide, etc.

The polyester-based thermoplastic elastomer system is not particularly limited. For example, polyether polyester and polyether polyester in which a crystalline polyester with a high melting temperature is used as a hard segment and a polyether or polyester with a low glass transition temperature as a soft segment can be mentioned. Block copolymers of polyester and polyester, etc.

The polyurethane-based thermoplastic elastomer system is not particularly limited. For example, a polyether with a crystallinity and a high melting temperature as the hard segment and a polyether with a low glass transition temperature or polyester as the soft segment can be mentioned. Polyurethane and polyester polyurethane, etc.

Among these thermoplastic elastomers, considering the balance of toughness improving effect and elastic modulus, styrene-based and/or olefin-based thermoplastic elastomers are preferred, styrene-based thermoplastic elastomers are more preferred, and SEBS is further preferred.

In the thermoplastic elastomer (C), in order to improve the compatibility with the crystalline polyamide resin (A), it has a terminal group (amine group or carboxyl group) and/or main chain that can interact with the polyamide resin (A). A reactive functional group that reacts with the amide group. The reactive functional group includes, for example, a carboxyl group, an acid anhydride group, an epoxy group, an oxazoline group, an amino group, an isocyanate group, and the like. Among these, considering the high reactivity with the polyamide resin (A), an acid anhydride group is preferable.

The content of the reactive functional group in the thermoplastic elastomer (C) is preferably 0.05-8% by mass, more preferably 0.1-5% by mass. The method for producing the thermoplastic elastomer (C) having the above-mentioned reactive functional group is not particularly limited, and it can be exemplified in the step of producing the thermoplastic elastomer, the method of reacting the compound having the above-mentioned reactive functional group, and the thermoplastic elastomer The method of mixing the pellets with the compound having the above-mentioned reactive functional group and kneading with an extruder to make it react.

Regarding the blending amount of the thermoplastic elastomer (C), as long as the thermoplastic elastomer (C) can be dispersed in the matrix of the above-mentioned polyamide resin (A) in micro-domains with a particle size of 5 μm or less, there is no particular limitation. Usually, it is 0.1-10 mass% with respect to 100 mass% of all resin components, Preferably it is 1-7 mass %.

The antioxidant (D) is preferably a compound that inhibits the deactivation of the reactive functional group possessed by the modified polyolefin resin (B) and the thermoplastic elastomer (C). "Inhibiting the deactivation of reactive functional groups" means "not reacting with reactive functional groups". That is, the antioxidant (D) does not interfere with the compound in which the modified polyolefin resin (B) and the thermoplastic elastomer (C) are finely dispersed in the matrix of the polyamide resin (A).

The antioxidant (D) is not particularly limited. For example, when the above-mentioned reactive functional groups possessed by the modified polyolefin resin (B) and the thermoplastic elastomer (C) are acid anhydride groups, examples include those that do not react with acid anhydride groups. Functional group hindered phenol antioxidants, sulfur antioxidants, phosphorus antioxidants and other organic antioxidants, and heat stabilizers, etc., are preferably hindered phenol antioxidants. One type of these may be used, or two or more types may be blended and used. As for the functional group which reacts with an acid anhydride group, an amino group, a hydroxyl group, etc. are mentioned, for example. In addition, the phenolic hydroxyl group of the hindered phenol structure should not be used as a functional group that reacts with an acid anhydride group. Amine-based antioxidants are not ideal because they react with the above-mentioned reactive functional groups to deactivate them.

The blending amount of the antioxidant (D) is preferably 0.01 to 1 part by mass, and more preferably 0.1 to 0.5 part by mass relative to 100 parts by mass of the total resin components. If the blending amount of the antioxidant (D) is within the above range, it will not only contribute to improving the sliding properties and toughness of the polyamide resin composition, but an appropriate prescription amount corresponding to the amount of the polyamide resin composition can prevent Oxidative degradation over time.

The mold release agent (E) is preferably a compound that inhibits the deactivation of the above-mentioned reactive functional groups possessed by the modified polyolefin resin (B) and the thermoplastic elastomer (C). "Inhibiting the deactivation of reactive functional groups" means "not reacting with reactive functional groups". That is, the release agent (E) is a compound that does not hinder the fine dispersion of the modified polyolefin resin (B) and the thermoplastic elastomer (C) in the matrix of the polyamide resin (A).

The release agent (E) is not particularly limited, and examples thereof include higher fatty acid ester compounds, amide compounds, polyethylene wax, polysiloxane, and polyethylene oxide. One type of these may be used, or two or more types may be blended and used. When the above-mentioned reactive functional group possessed by the modified polyolefin resin (B) and the thermoplastic elastomer (C) is an acid anhydride group, the release agent (E) is preferably a higher fatty acid ester compound. In addition, the higher fatty acid is a fatty acid with a carbon number of more than 10, preferably a fatty acid with a carbon number of 11-30. Metal salt compounds are undesirable because they react with the above-mentioned reactive functional groups to deactivate them.

The blending amount of the release agent (E) is preferably 0.05 to 1 part by mass, and more preferably 0.1 to 0.8 part by mass relative to 100 parts by mass of all resin components. If the blending amount of the release agent (E) is within the above range, it not only contributes to the improvement of the sliding properties and toughness of the polyamide resin composition, but also ensures proper release properties.

The antioxidant (D) and the release agent (E) do not hinder the fine dispersion of the modified polyolefin resin (B) and the thermoplastic elastomer (C) in the matrix of the polyamide resin (A). Therefore, the modified polyolefin resin (B) and the thermoplastic elastomer (C) react efficiently with the polyamide resin (A), and the polyamide resin (A) has a particle diameter of 5 μm or less. Micro-domains are slightly dispersed. As a result, it is believed that the effect of improving the sliding properties of the modified polyolefin resin (B) and the effect of improving the toughness of the thermoplastic elastomer (C) will effectively work to exhibit the unique effects of the present invention. The particle size is preferably 4 μm or less, more preferably 3.5 μm or less. The lower limit of the above particle size is not particularly limited, and considering the fluidity, it is preferably 1 μm or more, and more preferably 2 μm or more.

The solid lubricant (F) has the effect of suppressing the decrease in toughness while contributing to improving the surface friction characteristics. It is believed that the addition of the solid lubricant (F) to the polyamide resin composition exhibits the unique characteristics of the present invention effect.

The solid lubricant (F) is not particularly limited, and fluorine lubricants and acrylic modified polyorganosiloxanes are preferred. One type of these may be used, or two or more types may be blended and used.

The above-mentioned fluorine-based lubricants include, for example, tetrafluoroethylene resin (PTFE), perfluoro-alkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer resin (FEP), and tetrafluoroethylene-ethylene Copolymer resin (ETFE), vinylidene fluoride resin (PVDF), chlorotrifluoroethylene resin (PCTFE), etc. Among these, considering the viewpoints of heat resistance and sliding characteristics, PTFE is preferable.

The average particle diameter of the above-mentioned fluorine-based lubricant is preferably 1 to 200 μm, more preferably 7 to 100 μm, and further preferably 10 to 50 μm. If the average particle size exceeds 200 μm, the dispersibility of the fluorine-based lubricant in the matrix of the polyamide resin (A) becomes poor, and the mechanical strength as a molded body tends to decrease. On the other hand, if the average particle size is less than 1 μm, the particles of the fluorine-based lubricant are likely to undergo secondary agglomeration, it becomes difficult to uniformly mix, and the mechanical strength as a molded body is likely to decrease.

Examples of the acrylic-modified polyorganosiloxane include those obtained by graft copolymerizing at least (meth)acrylate to polyorganosiloxane. In particular, it is preferably obtained by graft copolymerizing a mixture of (meth)acrylate 70% by mass or more and other copolymerizable monomers 30% by mass or less to polyorganosiloxane at a mass ratio of 5/95 to 95/5. By.

The above-mentioned (meth)acrylates include, for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, Acrylates such as isooctyl acrylate, n-octyl acrylate, 2-hydroxyethyl acrylate, 2-methoxyethyl acrylate, etc.; methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, methyl N-propyl acrylate, n-butyl methacrylate, isobutyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-lauryl methacrylate, 2-hydroxyethyl methacrylate , Methacrylates such as 2-ethoxyethyl methacrylate, etc. One kind of these may be used, or two or more kinds may be blended and used. Among these, it is preferable to use methyl methacrylate as at least one component.

With regard to the above-mentioned other copolymerizable monomers, for example, styrene compounds such as styrene, vinyl toluene, and α-methylstyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile; vinyl chloride, vinylidene chloride, etc. Halogenated olefins such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated amides such as acrylamide, methacrylamide, and N-methylol acrylamide; acrylic acid, methacrylic acid, horse Monomers with one double bond such as unsaturated carboxylic acids such as acid anhydride; ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, methacrylic acid Polyunsaturated monomers such as allyl ester, triallyl cyanurate, triallyl isocyanurate, etc. One kind of these may be used, or two or more kinds may be blended and used.

The average particle diameter of the acrylic modified polyorganosiloxane is preferably 1 to 500 μm, more preferably 10 to 400 μm, and further preferably 30 to 350 μm. If the average particle size exceeds 500 μm, the dispersibility of the acrylic-modified polyorganosiloxane in the matrix of the polyamide resin (A) becomes poor, and the mechanical strength as a molded body tends to decrease. On the other hand, if the average particle diameter is less than 1 μm, the acrylic-modified polyorganosiloxane particles are likely to undergo secondary aggregation, and it becomes difficult to uniformly mix, and the mechanical strength as a molded body is likely to decrease.

The blending amount of the solid lubricant (F) is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass relative to 100% by mass of all resin components. If it is 0.1% by mass or more, it is effective to improve wear resistance, sliding stability, and surface lubricity. On the other hand, if it is 20% by mass or less, the mechanical properties of the polyamide resin composition are effectively improved, especially the toughness.

In the polyamide resin composition of the present invention, as long as the modified polyolefin resin (B) and the thermoplastic elastomer (C) are finely dispersed in the matrix of the polyamide resin (A), as long as it is within the range of ( In addition to the components A) to (F), carbon black, copper oxide, alkali metal halide, light or heat stabilizer, crystal, which is a weather resistance modifier blended in the conventional polyamide resin composition, can also be blended. Nucleating agent, antistatic agent, pigment, dye, coupling agent and other additives. In addition, by blending the filler in a range that does not impair the toughness of the polyamide resin composition, the strength and rigidity of the molded product can be greatly improved. Examples of fillers include glass fibers, carbon fibers, metal fibers, aramid fibers, asbestos, potassium titanate whiskers, wollastonite, glass flakes, glass beads, talc, mica, clay, and calcium carbonate. , Barium sulfate, titanium oxide, aluminum oxide, etc. In the polyamide resin composition of the present invention, the total of the above-mentioned components (A) to (F) should preferably account for 70% by mass or more, more preferably 80% by mass or more, and further preferably 90% by mass or more.

The polyamide resin composition of the present invention is produced by kneading each component using a kneading device such as a uniaxial extruder, a biaxial extruder, or a pressure kneader, for example. The mixing device should be a two-axis extruder. In one embodiment, the above-mentioned components (A) to (F), and pigments depending on the application are mixed, and put into a two-axis extruder. A polyamide resin composition with excellent sliding properties can be produced by uniformly kneading by a two-axis extruder. The mixing temperature of the two-axis extruder should be 220-300℃, and the mixing time should be about 2-15 minutes.

The polyamide resin composition of the present invention can be widely used as a raw material for sliding parts such as electrical and electronic parts, automobile parts, construction parts, and industrial parts that require sliding properties. As for sliding parts, specific examples include bearings, gears, door checkers, chain guide parts, and the like. [Example]

Hereinafter, the present invention will be specifically explained using examples, but the present invention is not limited to these examples. In addition, the physical properties of the polyamide resin molded products obtained in the following examples were measured based on the following test methods.

The raw materials used in the examples and comparative examples are as follows. As the crystalline polyamide resin (A), (A1) to (A3) are used. (A1) Polyamide 66 (RV=3.4): EPR34W (manufactured by Shanghai Shenma Plastic Technology Co., Ltd.), melting point 265°C (A2) Polyamide 66 (RV=2.8): Vydyne 21FSR (manufactured by Ascend), melting point 265°C (A3) Polyamide 66 (RV=2.4): EPR24 (manufactured by Shanghai Shenma Plastic Technology Co., Ltd.), melting point 265°C

As the modified polyolefin resin (B), (B1) and (B2) are used. (B1) Maleic anhydride modified polyethylene: MODIC DH0200 (manufactured by Mitsubishi Chemical Corporation) (B2) Unmodified polyethylene: hi-zex 6203B (manufactured by Prime Polymer Co., Ltd.)

As the thermoplastic elastomer (C), (C1) and (C2) are used. (C1) Maleic anhydride modified SEBS: Tuftec M-1943 (manufactured by Asahi Kasei Co., Ltd.) (C2) Unmodified SEBS: Tuftec H-1221 (manufactured by Asahi Kasei Co., Ltd.)

As the antioxidant (D), (D1) and (D2) are used. (D1) Hindered phenol-based antioxidant: triethylene glycol-bis-3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate (manufactured by SONGWON, SONGNOX2450) (D2) Amine-based antioxidant: NONFLEX DCD (manufactured by Seiko Chemical Co., Ltd.)

As the mold release agent (E), (E1) to (E3) are used. (E1) Aliphatic ester: Ricolb WE-40 (manufactured by Clariant Japan K.K.) (E2) Magnesium stearate: N.P.1500-S (manufactured by Dannan Chemical Industry Co., Ltd.) (E3) Calcium octadecanoate: Licomont Cav102 (manufactured by Clariant Japan K.K.)

As the solid lubricant (F), (F1) to (F3) are used. (F1) PTFE: KT-300M (manufactured by Kitamura Co., Ltd.), average particle size 15μm (F2) Acrylic modified polyorganosiloxane: CHALINE R-170S (manufactured by Nissin Chemical Industry Co., Ltd.), average particle size 30μm (F3) Polysiloxane powder: KMP-590 (manufactured by Shin-Etsu Silicone Co. Ltd.), average particle size 2μm In addition, the average particle size was measured by the following method. Observe each solid lubricant with a differential interference microscope and take pictures. Randomly select 10 particles among the particles in the micrograph, measure the long diameter of the selected particles, and use the average value as the average particle diameter.

[Examples 1-13, Comparative Examples 1-15] The evaluation samples were manufactured by weighing the raw materials at the blending ratio of the polyamide resin composition shown in Table 1 and Table 2, mixing them with a roller, and putting them into a two-axis extruder. The setting temperature of the two-axis extruder is 250℃～300℃, and the mixing time is 5～10 minutes. Using the obtained pellets, various evaluation samples were formed by an injection molding machine. The cylinder temperature of the injection molding machine is set to 250°C to 290°C, and the mold temperature is set to 80°C.

Various evaluation and measurement methods are as follows. The evaluation and measurement results are shown in Table 1 and Table 2. 1. The relative viscosity of polyamide resin (96% sulfuric acid solution method) Using a Ubbelohde viscosity tube, the measurement was performed at 25° C. with a 96% by mass sulfuric acid solution and a polyamide resin concentration of 1 g/dl.

2. Melting point of polyamide resin A differential scanning calorimeter (Seiko Instruments Inc., EXSTAR 6000) was used for measurement at a temperature increase rate of 20°C/min, and the endothermic peak temperature was determined.

3. Tensile strength, tensile modulus of elasticity, tensile elongation Measured in accordance with ISO178.

4. Impact resistance Measured in accordance with ISO179-1.

5. Sliding properties: Using a thrust abrasion tester, a cylindrical molded product made of polyoxymethylene (POM) was brought into contact with a polyamide resin flat plate, and the polyamide resin flat plate was evenly coated on the surface with a certain amount of blending Molybdenum disulfide grease, silica sand and pozzolan are mixed in a mass ratio of 1:1:1, and the dust is ^{continuously mixed under the conditions of 30 minutes, 30kgf/cm 2} , and speed 40mm/sec. slide. After that, the dynamic friction coefficient was calculated from the value of the weight difference before and after the abrasion and the abrasion load after convergence during the friction test.

6. Particle size Cut out a shaped evaluation sample, and make a section using a microtome equipped with a glass knife. Observe the obtained section with a differential interference microscope and take photos. Among the microdomains of the modified polyolefin resin (B) and the thermoplastic elastomer (C) in the micrograph, randomly select 10 microdomains with the largest dispersion diameter, measure the long diameter of the selected microdomains, and average them The value is taken as the particle size.

[Table 1]

[Table 2]

In Examples 1-13, a polyamide resin composition with Charpy impact strength of 6 kJ/m ² or more, low abrasion amount and dynamic friction coefficient, and both toughness and sliding properties can be obtained. In addition, there is no major loss in tensile modulus of elasticity and tensile elongation. In Comparative Examples 1 to 3, because of insufficient toughness, brittle surface damage during sliding cannot be suppressed by the alloy system of polyolefin resin alone, and the amount of wear increased. Although the comparative examples 4 to 7 have sufficient toughness, the tensile modulus of elasticity is not sufficient, dust will enter the surface of the material, and it is easy to wear, and it is difficult to exert the sliding modification effect of the polyolefin resin. Comparative Example 8 or 12 is not ideal because it is formulated with unmodified polyolefin resin or unmodified thermoplastic elastomer, it is difficult to form micro-dispersed micro domains, and it is difficult to exhibit excellent physical properties. In Comparative Examples 9-11, amine antioxidants or fatty acid metal salts were used to react with the reactive functional groups of the polyolefin resin or thermoplastic elastomer to deactivate the reactive functional groups, so micro-dispersion could not be formed.之微域. Comparative Example 13 was mixed with a solid lubricant, but because it was purely silicone powder, agglomerates were easily formed in the polyamide resin composition, so brittle failure was likely to occur at the interface between the silicone powder and the polyamide resin. The amount of wear becomes larger. In Comparative Examples 14 and 15, solid lubricants were blended, but polyolefin resins or thermoplastic elastomers were not blended. Therefore, although the coefficient of dynamic friction was low, brittle failure could not be suppressed and the amount of wear could not be reduced.

Fig. 1 is an image obtained by observing the cross-section of Example 2 with a differential interference microscope. It can be seen that the polyolefin resin and the thermoplastic elastomer are uniformly and finely dispersed in the matrix of the polyamide resin in micro-domains with a particle size of 5 μm or less. On the other hand, FIG. 2 is an image obtained by observing the cross section of Comparative Example 10 with a differential interference microscope. The above two kinds of modified materials are unevenly dispersed in the matrix of polyamide resin, and no micro-dispersion is formed. In addition, there are large micro-domains, which may cause stress concentration during wear and become the starting point of wear. [Industrial availability]

The polyamide resin composition of the present invention is a molding material that has both excellent toughness and sliding properties. It is especially suitable for sliding parts requiring excellent wear resistance and sliding stability. As an engineering plastic that can be used in a wide range of fields, it is expected to make a great contribution to the industry.

no.

[Fig. 1] An image obtained by observing the cross-section of the evaluation sample prepared in Example 2 with a differential interference microscope. [Figure 2] An image obtained by observing the cross-section of the evaluation sample produced in Comparative Example 10 with a differential interference microscope.

Claims (8)

A polyamide resin composition for sliding parts, containing a crystalline polyamide resin (A), and a reactive functional group capable of reacting with the terminal group and/or main chain amide group of the polyamide resin (A) The modified polyolefin resin (B) and/or the thermoplastic elastomer (C) with reactive functional groups that can react with the end groups and/or main chain amide groups of the polyamide resin (A), antioxidants (D), release agent (E), and solid lubricant (F); The modified polyolefin resin (B) and/or the thermoplastic elastomer (C) are dispersed in the matrix of the polyamide resin (A) in micro-domains with a particle size of 5 μm or less. The polyamide resin composition for sliding parts of claim 1, wherein the antioxidant (D) and the release agent (E) inhibit the modified polyolefin resin (B) and the thermoplastic elastomer (C) A compound that has the inactivation of the reactive functional group. According to claim 1 or 2, the polyamide resin composition for sliding parts, wherein the reactive functional group is an acid anhydride group. According to claim 1 or 2, the polyamide resin composition for sliding parts, wherein the antioxidant (D) is a hindered phenol-based antioxidant. According to claim 1 or 2, the polyamide resin composition for sliding parts, wherein the release agent (E) is a higher fatty acid ester compound. According to claim 1 or 2, the polyamide resin composition for sliding parts, wherein the thermoplastic elastomer (C) is a styrene-based and/or olefin-based thermoplastic elastomer. According to claim 1 or 2, the polyamide resin composition for sliding parts, wherein the solid lubricant (F) is a fluorine-based lubricant and/or acrylic modified polyorganosiloxane. A sliding part obtained from the polyamide resin composition for sliding parts according to any one of claims 1 to 7.

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