TW202118830A - 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 has excellent moldability and thermal stability, and which is suitable for use in molding of a sliding component that requires excellent sliding characteristics, especially excellent wear resistance with the intermediary of particles (hereinafter also referred to as dust) having high hardness and excellent sliding stability. A polyamide resin composition for sliding components according to the present invention contains: (A) a crystalline polyamide resin; (B) a modified polyolefin resin having a reactive functional group that is reactive with an end group and/or a main chain amide group of the polyamide resin (A); (C) a thermoplastic elastomer having a reactive functional group that is reactive with an end group and/or a main chain amide group of the polyamide resin (A); (D) an antioxidant; and (E) a mold release agent. With respect to this polyamide resin composition for sliding components, the modified polyolefin resin (B) and the thermoplastic elastomer (C) are 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.

In terms 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

[The problem to be solved by the invention]

The object of the present invention is to provide a polyamide resin composition that has excellent moldability and heat stability, and is suitable for use in abrasion resistance of particles with high hardness (hereinafter, also referred to as dust) that require sliding properties. Forming of sliding parts with excellent performance and sliding stability. [Means to solve the problem]

The inventors of the present application have intensively studied in order to achieve the above-mentioned problems, and found that antioxidants and mold release agents added to improve moldability and heat resistance improve the sliding properties, and reached 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 of the polyamide resin (A) and/or the main chain amide group The modified polyolefin resin (B), the thermoplastic elastomer (C) with the reactive functional group that can react with the terminal group and/or the main chain amide group of the polyamide resin (A), the antioxidant (D ), and release agent (E); The modified polyolefin resin (B) and 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] Such as the polyamide resin composition for sliding parts in any one of [1] to [4], wherein the release agent (E) is a higher fatty acid ester compound. [6] Such as the polyamide resin composition for sliding parts in any one of [1] to [5], wherein the thermoplastic elastomer (C) is a styrene-based and/or olefin-based thermoplastic elastomer. [7] A sliding part is obtained from the polyamide resin composition for sliding parts as in any one of [1] to [6]. [Effects of Invention]

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

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).), having a terminal group capable of reacting with the terminal group and/or main chain amide group of the above-mentioned polyamide resin (A) The reactive functional group of the thermoplastic elastomer (C) (hereinafter also referred to as thermoplastic elastomer (C).), antioxidant (D), and release agent (E).

The blending amount of each component is based on the mass parts when the total of all resin components of the crystalline polyamide resin (A), modified polyolefin resin (B), and thermoplastic elastomer (C) is 100 parts by mass. Said. 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℃), 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 are 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, and 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, and 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, polyetheresters in which crystalline and high melting temperature polyamide is used as the hard segment and polyether or polyester with a low glass transition temperature are used as the soft segment. 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 a hard segment and a polyether with a low glass transition temperature or a polyester as a soft segment can be mentioned. Polyurethane and polyester polyurethane, etc.

Among these thermoplastic elastomers, considering the balance of toughness improvement 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 be combined 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 to 8% by mass, more preferably 0.1 to 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 by the method of reacting the compound having the above-mentioned reactive functional group in the step of producing the thermoplastic elastomer, and the method of making the thermoplastic elastomer A method of mixing the pellets with the compound having the above-mentioned reactive functional group and the like and kneading with an extruder or the like 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 polyamide resin (A) in the micro-domains with a particle diameter 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 less desirable 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 composition. 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 interfere with 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, higher fatty acids are fatty acids with a carbon number of more than 10, preferably fatty acids 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 slidability and toughness of the polyamide resin composition, but also ensures appropriate 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, thereby exhibiting 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 aforementioned particle size is not particularly limited, but from the viewpoint of fluidity, it is preferably 1 μm or more, and more preferably 2 μm or more.

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 in which the modified polyolefin resin (B) and the thermoplastic elastomer (C) are finely dispersed in the matrix of the polyamide resin (A), the above ( In addition to the components A)~(E), 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 agents, lubricating materials, antistatic agents, pigments, dyes, coupling agents and other additives. In addition, by blending fillers, 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 (E) 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. For an implementation aspect, the above-mentioned components (A) to (E), 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.)

[Examples 1 to 7, Comparative Examples 1 to 8] 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~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. Slidability: Using a thrust abrasion tester, a cylindrical molded product made of polyoxymethylene (POM) was brought into contact with a polyamide resin plate, and the polyamide resin plate was evenly coated on the surface with a certain amount of blending Molybdenum disulfide grease, silica sand and volcanic ash 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 micro-domains of the modified polyolefin resin (B) and the thermoplastic elastomer (C) in the microscope photograph, 10 micro-domains with the largest dispersion diameter are arbitrarily selected, and the long diameters of the selected micro-domains are measured and averaged The value is taken as the particle size.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Composition (parts by mass) Polyamide resin (A1) 92 93 89 96 90 Polyamide resin (A2) 92 Polyamide resin (A3) 92 Polyolefin resin (B1) 3 3 3 2 6 3 3 Polyolefin resin (B2) Thermoplastic elastomer (C1) 5 5 5 5 5 1 7 Thermoplastic elastomer (C2) Antioxidant (D1) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Antioxidant (D2) Release agent (E1) 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Release agent (E2) Release agent (E3) Tensile properties Tensile strength (MPa) 70 69 69 72 68 76 68 Tensile modulus of elasticity (GPa) 2.8 2.8 2.8 2.9 2.7 3.2 2.7 Tensile elongation (%) 65 65 65 63 67 56 70 Impact characteristics Charpy impact strength (kJ/m ² ) 8.7 8.5 8.3 8.1 9.0 6.8 9.4 Wear characteristics Abrasion (mg/km) 25 27 28 twenty three 29 twenty three 29 Dynamic friction coefficient 0.06 0.06 0.06 0.08 0.06 0.07 0.07 Dispersion diameter Particle size (μm) 2.6 2.8 2.8 2.5 3.2 2.1 3.5

[Table 2] Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Comparative example 6 Comparative example 7 Comparative example 8 Composition (parts by mass) Polyamide resin (A1) 100 98 95 92 92 92 92 92 Polyamide resin (A2) Polyamide resin (A3) Polyolefin resin (B1) 2 3 3 3 3 Polyolefin resin (B2) 3 Thermoplastic elastomer (C1) 5 5 5 5 5 Thermoplastic elastomer (C2) 5 Antioxidant (D1) 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Antioxidant (D2) 0.2 Release agent (E1) 0.4 0.4 0.4 0.4 0.4 Release agent (E2) 0.4 Release agent (E3) 0.4 0.4 Tensile properties Tensile strength (MPa) 81 78 73 73 73 71 72 68 Tensile modulus of elasticity (GPa) 3.3 3.2 3.0 3.0 3.0 3.0 3.1 3.0 Tensile elongation (%) 50 51 60 56 51 54 51 57 Impact characteristics Charpy impact strength (kJ/m ² ) 4.5 5.3 7.2 6.6 5.7 5.9 5.5 6.4 Wear characteristics Abrasion (mg/km) 37 33 37 43 40 37 39 36 Dynamic friction coefficient 0.12 0.09 0.13 0.12 0.10 0.10 0.12 0.10 Dispersion diameter Particle size (μm) - 3.1 2.6 14.3 10.4 13.4 12.4 12.8

The Charpy impact strengths of Examples 1 to 7 are all above 6 kJ/m ² , and a composition with higher toughness is obtained compared to the polyamide without modification. In addition, there is no major loss in tensile modulus of elasticity or tensile elongation. Compared with the comparative examples 1-8, the abrasion amount and the dynamic friction coefficient after the sliding test of the intermediary dust also have better abrasion resistance. In Comparative Examples 1 and 2, because of insufficient toughness, brittle surface damage during sliding cannot be suppressed, and the amount of wear increased. Although Comparative Example 3 has sufficient toughness, it is difficult to exert the sliding modification effect of the polyolefin resin. In Comparative Example 4, it is difficult to form micro-dispersed micro-domains because the formulation contains unmodified thermoplastic elastomer, and the particle size is difficult to exhibit excellent physical properties, so it is not suitable. Comparative Examples 5, 6, and 7 use amine antioxidants and fatty acid metal salts, respectively, and react with the reactive functional groups of the modified polyolefin resin or thermoplastic elastomer to deactivate the reactive functional groups. Unable to form micro-dispersed micro domains In Comparative Example 8, because the formulation contained unmodified polyolefin resin, it was difficult to form micro-dispersed micro domains, and the sliding modification effect could not be exerted uniformly on the surface, and the amount of abrasion increased.

Fig. 1 is an image obtained by observing the cross-section of Example 1 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 6 with a differential interference microscope. The above two kinds of modified materials are unevenly dispersed in the matrix of the polyamide resin, and no micro-dispersion domains are 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 wear resistance and sliding stability through particles with high hardness. 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.

[Fig. 1] An image obtained by observing the cross section of the evaluation sample prepared in Example 1 with a differential interference microscope. [Fig. 2] An image obtained by observing the cross section of the evaluation sample produced in Comparative Example 6 with a differential interference microscope.

Claims (7)

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 of the polyamide resin (A) and/or the main chain amide group The modified polyolefin resin (B), the thermoplastic elastomer (C) with the reactive functional group that can react with the terminal group and/or the main chain amide group of the polyamide resin (A), the antioxidant (D ), and release agent (E); The modified polyolefin resin (B) and 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. A sliding part obtained from the polyamide resin composition for sliding parts according to any one of claims 1 to 6.

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