Polyamide resin composition

Abstract

This polyamide resin composition comprises a polyamide resin (A), a polyolefin-based graft copolymer (B) having an aromatic-ring-containing polymer as a side chain, and a compatibilizing agent (C).

Description

Technical Field

[0001] The present invention relates to a polyamide resin composition. This application claims priority based on Japanese Patent Application No. 2022-048923 filed in Japan on March 24, 2022, Japanese Patent Application No. 2022-088612 filed in Japan on May 31, 2022, and Japanese Patent Application No. 2022-167193 filed in Japan on October 18, 2022, and incorporates the contents herein by reference.

Background Art

[0002] Polyamide resins are excellent in sliding properties, moldability, mechanical properties, chemical resistance, etc. Polyamide resins have been widely used as component materials for industrial materials, automobiles, electric and electronic devices, and industrial applications.

[0003] In recent years, resin substitution of metal members has been progressing in the automotive and electric and electronic fields. Recently, in the automotive field, from the viewpoints of weight reduction for fuel efficiency improvement, cost reduction, and rationalization of the assembly process, a molding material with more excellent sliding properties and excellent mechanical properties such as toughness and impact resistance is required.

[0004] As a method for further improving the sliding properties of polyamide resins, it is known to compound and knead a solid lubricant such as a fluororesin, graphite, or molybdenum disulfide into the polyamide resin.

[0005] Patent Documents 2 to 4 disclose polyamide resin compositions in which a fluororesin is compounded into a polyamide resin to enhance sliding properties. Further, Patent Document 1 discloses a sliding member for a power transmission guide obtained by dispersing a polyolefin resin in a polyamide resin.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

[0007] As a technique for improving sliding characteristics, it has been proposed to blend a fluororesin with a polyamide resin. Examples of the fluororesin to be blended include polytetrafluoroethylene. However, when polytetrafluoroethylene is used, in order to finely disperse polytetrafluoroethylene, it is necessary to perform melt kneading under high shear conditions at a temperature equal to or higher than the melting point of polytetrafluoroethylene. As a result of melt kneading, there is a problem that the polyamide resin deteriorates and the mechanical strength decreases.

[0008] Also, as a technique for improving sliding characteristics, it has been proposed to blend a polyolefin resin with a polyamide resin. However, the melt viscosities of the polyamide resin and the polyolefin resin are different. Furthermore, depending on the shear rate applied during production, the melt viscosities of the polyamide resin and the polyolefin resin also differ greatly. As a result of the large difference in the melt viscosities of the polyamide resin and the polyolefin resin, the morphological state of the polyolefin resin is greatly different, which has a problem of greatly affecting the mechanical properties and sliding characteristics.

[0009] The present invention has been made in view of the above circumstances, and an object thereof is to provide a polyamide resin composition having excellent sliding characteristics and mechanical characteristics and stable sliding characteristics that do not depend on the shear rate in the injection molding process during its production. [Means for Solving the Problems]

[0010] The present invention includes the following aspects. [1] A polyamide resin composition containing (A) a polyamide resin, (B) a polyolefin-based graft copolymer having a polymer having an aromatic ring in the side chain, and (C) a compatibilizer.

[0011] [2] The polyamide resin composition according to [1] above, wherein the (C) compatibilizer contains at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton.

[0012] [3] The content of the polyolefin-based graft copolymer having a polymer having an aromatic ring in the side chain (B) with respect to 100 parts by mass of the (A) polyamide resin is 1 to 15 parts by mass, and the content of the (C) compatibilizer is 0.2 to 10 parts by mass. The polyamide resin composition according to [1] or [2] above.

[0013] [4] The polyamide resin composition according to any one of [1] to [3] above, wherein the (C) compatibilizer contains at least an olefin skeleton.

[0014] [5] The polyamide resin composition according to [4] above, wherein the mass ratio ((C) / (B)) of the (C) compatibilizer to the polyolefin-based graft copolymer having a polymer having an aromatic ring in the side chain (B) is 0.01 to 2.

[0015] [6] The polyamide resin composition according to any one of [1] to [3] above, wherein the (C) compatibilizer contains at least an aromatic ring skeleton.

[0016] [7] The polyamide resin composition according to [6] above, wherein the mass ratio ((C) / (B)) of the (C) compatibilizer to the polyolefin-based graft copolymer having a polymer having an aromatic ring in the side chain (B) is 0.001 to 1.

[0017] [8] The polyamide resin composition according to [6] or [7] above, wherein the (C) compatibilizer has at least a reactive functional group with the (A) polyamide resin.

[0018] 〔9〕The polyamide resin composition according to the above 〔8〕, wherein the reactive functional group contains a structural unit derived from a carboxylic acid anhydride.

[0019] 〔10〕The polyamide resin composition according to any one of the above 〔1〕 to 〔9〕, wherein the (C) compatibilizer has at least an amide bond in the side chain.

[0020] 〔11〕The polyamide resin composition according to any one of the above 〔1〕 to 〔10〕, wherein the (B) polyolefin-based graft copolymer having an aromatic ring-containing polymer in the side chain has at least polyethylene in the main chain.

[0021] 〔12〕Furthermore, with respect to 100 parts by mass of the (A) polyamide resin, it contains 0.01 to 5 parts by mass of a copper compound and 0.05 to 5 parts by mass of a halide of a metal selected from the group consisting of alkali metals and alkaline earth metals. The polyamide resin composition according to any one of the above 〔1〕 to 〔11〕.

[0022] 〔13〕A molded article obtained by molding the polyamide resin composition according to any one of the above 〔1〕 to 〔12〕.

[0023] 〔14〕A sliding member made of the polyamide resin composition according to any one of the above 〔1〕 to 〔12〕.

[0024] 〔15〕A method for producing a polyamide resin composition, characterized by melt-kneading (A) a polyamide resin, (B) a polyolefin-based graft copolymer having an aromatic ring-containing polymer in the side chain, and (C) a compatibilizer.

[0025] 〔16〕The method for producing a polyamide resin composition according to the above 〔15〕, wherein the polyamide resin composition is the polyamide resin composition according to any one of the above 〔1〕 to 〔12〕.

Advantages of the Invention

[0026] According to the present invention, a polyamide resin composition is obtained which is excellent in moldability, heat resistance, sliding properties and mechanical properties, and has stable sliding properties that do not depend on the shear rate in the injection molding process during its production.

Mode for Carrying Out the Invention

[0027] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present invention, and is not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of its gist.

[0028] In this specification, "polyamide" means a polymer having an amide (-NHCO-) group in the main chain. Regarding numerical ranges, "A or more and B or less" may be expressed as "A to B". For example, when described as "1 to 10 parts by mass", it means a numerical range from 1 part by mass to 10 parts by mass, including the lower limit value (1 part by mass) and the upper limit value (10 parts by mass), that is, "1 part by mass or more and 10 parts by mass or less".

[0029] <Polyamide Resin Composition> The polyamide resin composition of the present embodiment is a polyamide resin composition containing (A) a polyamide resin (hereinafter sometimes referred to as component (A)), (B) a polyolefin-based graft copolymer having an aromatic ring polymer in the side chain (hereinafter sometimes referred to as component (B)), and (C) a compatibilizer (hereinafter sometimes referred to as component (C)).

[0030] Hereinafter, each component of the polyamide resin composition of the present embodiment will be described.

[0031] ≪(A) Polyamide Resin≫ In this embodiment, examples of the (A) polyamide resin include, but are not limited to, (a-1) polyamides obtained by ring-opening polymerization of lactams, (a-2) polyamides obtained by self-condensation of ω-aminocarboxylic acids, (a-3) polyamides obtained by condensing diamines and dicarboxylic acids, and copolymers thereof. As the (A) polyamide resin, only one kind of the polyamide may be used alone, or a mixture of two or more kinds may be used.

[0032] Examples of the lactam used for producing the (a-1) polyamide include, but are not limited to, pyrrolidone, caprolactam, undecalactam, dodecalactam, etc.

[0033] Examples of the ω-aminocarboxylic acid used for producing the (a-2) polyamide include, but are not limited to, ω-amino fatty acids which are ring-opening compounds of the lactam with water. In addition, as the lactam or the ω-aminocarboxylic acid, two or more kinds of monomers may be used in combination for condensation.

[0034] Examples of the diamine (monomer) used for producing the (a-3) polyamide include, but are not limited to, linear aliphatic diamines, branched aliphatic diamines, alicyclic diamines, aromatic diamines, etc.

[0035] Examples of the linear aliphatic diamine include, but are not limited to, hexamethylenediamine, pentamethylenediamine, etc.

[0036] Examples of the branched aliphatic diamine include, but are not limited to, 2-methylpentanediamine, 2-ethylhexamethylenediamine, etc.

[0037] Examples of the alicyclic diamine include, but are not limited to, cyclohexanediamine, cyclopentanediamine, cyclooctanediamine, etc.

[0038] Examples of the aromatic diamine include, but are not limited to, p-phenylenediamine, m-phenylenediamine, etc.

[0039] Examples of the dicarboxylic acid (monomer) used for producing the (a-3) polyamide include, but are not limited to, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, etc.

[0040] Examples of the aliphatic dicarboxylic acid include, but are not limited to, adipic acid, pimelic acid, sebacic acid, etc.

[0041] Examples of the alicyclic dicarboxylic acid include, but are not limited to, cyclohexanedicarboxylic acid, etc.

[0042] Examples of the aromatic dicarboxylic acid include, but are not limited to, phthalic acid, isophthalic acid, etc.

[0043] The diamine and the dicarboxylic acid as the above-mentioned monomers may be condensed alone or in combination of two or more kinds.

[0044] Examples of the polyamide as the component (A) include, but are not limited to, polyamide 4 (poly-α-pyrrolidone), polyamide 6 (polycaproamide), polyamide 10, polyamide 11 (polyundecanamide), polyamide 12 (polydodecanamide), polyamide 46 (polytetramethylene adipamide), polyamide 56, polyamide 66 (polyhexamethylene adipamide), polyamide 410, polyamide 610 (polyhexamethylene sebacamide), polyamide 612 (polyhexamethylene dodecamide), polyamide 1010, polyamide 4T, polyamide 6T (polyhexamethylene terephthalamide), polyamide 9T (polynonamethylene terephthalamide), polyamide 10T, polyamide 6I (polyhexamethylene isophthalamide), polyamide 2Me5T (poly-2-methylpentamethylene terephthalamide (hereinafter, the methyl group may be denoted as Me)), polyamide MXD6 (polymetaxylylene adipamide), polyamide PXD12 (polyparaxylylene dodecamide), and copolyamides containing at least one of these as a constituent component, etc.

[0045] (Proportion of component (A)) From the viewpoint of improving sliding properties, the component (A) of the present embodiment preferably comprises a polyamide resin mainly composed of polyamide 66, polyamide 46, polyamide 4T, polyamide 6T, polyamide 9T, polyamide 10T, polyamide 6, polyamide 410, and copolyamides containing at least one of these as a constituent component. Hereinafter, the "main component" means a component having a content of 50% by mass or more, more preferably 65% by mass to 100% by mass, and even more preferably 70% by mass to 100% by mass with respect to the total mass of the (A) polyamide resin.

[0046] Also, from the viewpoint of improving heat resistance, a polyamide resin mainly composed of polyamide 66, polyamide 46, polyamide 4T, polyamide 6T, polyamide 9T, polyamide 10T, polyamide 6, polyamide 410, and copolyamides containing at least one of these as a constituent component is preferable, and a polyamide resin mainly composed of polyamide 66 is more preferable.

[0047] As the component (A) in the polyamide resin composition of the present embodiment, known ones can be used, and commercial products may also be used.

[0048] ≪(B) Polyolefin-based graft copolymer having an aromatic ring-containing polymer in the side chain≫ The polyolefin-based graft copolymer having an aromatic ring-containing polymer in the side chain (B) in the present embodiment is not particularly limited as long as it is a polyolefin-based graft copolymer having a polymer containing an aromatic ring in the side chain.

[0049] The aromatic ring is preferably a C6-10 aryl group, and more preferably a phenyl group. The aromatic ring-containing polymer is preferably a polymer containing a C2-6 alkylene group substituted with a C6-10 aryl group as a repeating unit, more preferably a polymer containing a C2-4 alkylene group substituted with a phenyl group as a repeating unit, and even more preferably polystyrene.

[0050] In addition to the aromatic ring-containing polymer, the side chain of the component (B) may further have a vinyl-based copolymer having no aromatic ring.

[0051] The main chain of the component (B) preferably has polyethylene.

[0052] By including the component (B), the sliding properties of the obtained polyamide resin composition are improved.

[0053] [Preparation method of component (B)] (B) The method for preparing the component is not particularly limited, but it can be easily prepared by a known radical reaction. As the method for preparing the (B) component, for example, a method can be mentioned in which a radical catalyst is added to a monomer constituting an olefin polymer component containing polyethylene and a monomer constituting a vinyl polymer having an aromatic ring, and they are kneaded and grafted. Further, a method can be mentioned in which a radical catalyst such as a peroxide is added to the olefin polymer component or the vinyl polymer component having an aromatic ring to generate free radicals, and the generated free radicals are melt-kneaded with the other polymer component and grafted.

[0054] By using a polyolefin-based graft copolymer having a main chain containing a polyolefin and a side chain containing an aromatic ring-containing polymer as the (B) component, it is possible to prevent the (B) component from dropping off from the polyamide resin, and a polyamide resin composition excellent in sliding properties, particularly wear resistance, can be obtained. Therefore, it is preferable.

[0055] (Content ratio of polystyrene in the (B) component) The (B) component preferably contains at least 50% by mass or more of polystyrene with respect to 100% by mass of the (B) component. Further, the content of polystyrene with respect to the total mass of the (B) component can be 100% by mass or less.

[0056] (Composition ratio of the (B) component) The ratio of the (b1) olefin polymer and the (b2) vinyl polymer containing an aromatic ring constituting the (B) component is preferably (b1):(b2) = 80:20 to 20:80 (mass ratio), and particularly preferably (b1):(b2) = 60:40 to 40:60. By satisfying the above ratio, the sliding properties of the obtained polyamide resin composition are improved.

[0057] (b2) The vinyl copolymer containing an aromatic ring exhibits high rigidity due to the high glass transition temperature characteristic of the aromatic ring. Also, in the vinyl copolymer containing an aromatic ring in (b2), when the temperature of the sliding surface rises due to the frictional force (frictional heat) applied to the sliding surface of the vinyl copolymer, the (B) component is prevented from easily sticking and fusing to the sliding parts such as the meshing parts of the mating material or the self-material on the sliding surface. As a result, the sliding characteristics are maintained for a long period, and in particular, the wear resistance is improved.

[0058] (Content ratio of component (B)) In the polyamide resin composition of this embodiment, the content ratio of the (B) component is preferably 1 to 15 parts by mass, more preferably 2 to 12 parts by mass, and still more preferably 3 to 10 parts by mass with respect to 100 parts by mass of the (A) polyamide resin. When the content ratio of the (B) component is at least the lower limit value, the sliding characteristics of the obtained polyamide resin composition are effectively exhibited. Also, when the content ratio of the (B) component is at most the upper limit value, the wear resistance and mechanical properties of the obtained polyamide resin composition are improved.

[0059] As the (B) component in the polyamide resin composition of this embodiment, known polyolefin-based graft copolymers having an aromatic ring polymer in the side chain can be used, and commercially available products may also be used.

[0060] ≪(C) Compatibilizer≫ The (C) compatibilizer in this embodiment is a compound that can improve the compatibility between the (A) component and the (B) component. As the (C) component, from the viewpoint of further excellent sliding characteristics, mechanical properties, heat resistance, long-term heat resistance, moldability, processability, etc., it is preferably included at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton.

[0061] As the compound containing an olefin skeleton, although not limited to the following, for example, at least one selected from low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), ultra-high molecular weight polyethylene (UHMWPE), very low-density polyethylene (VLDPE) obtained by metallocene catalysis, polyethylene, alpha-olefin, diolefin, etc. can be used. In addition, in this specification, the definition of an olefin skeleton is a compound composed only of carbon atoms and hydrogen atoms.

[0062] As the compound containing an aromatic ring skeleton, although not limited to the following, for example, at least one selected from polystyrene having an aromatic ring skeleton, phenylene ether, modified polyphenylene ether, etc. can be used.

[0063] As the compound containing an olefin skeleton and an aromatic ring skeleton, although not limited to the following, for example, at least one selected from styrene / butadiene / styrene block copolymer (SBS), its hydrogenated product styrene / ethylene·butylene / styrene block copolymer (SEBS), styrene / butadiene copolymer (SBR), its hydrogenated product styrene / ethylene / butylene copolymer (HSBR), styrene / isoprene / styrene block copolymer (SIS), and its hydrogenated product styrene / ethylene·propylene / styrene block copolymer (SEPS) can be used.

[0064] Examples of alpha-olefins include, but are not limited to, ethylene, propylene, butene-1, octene-1, butadiene, etc.

[0065] Examples of diolefins include, but are not limited to, diolefin homopolymers, copolymers, etc.

[0066] The compatibilizer (C) in the present embodiment more preferably has at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton in the main chain, even more preferably has only one of an olefin skeleton and a styrene skeleton, and particularly preferably has only an olefin skeleton.

[0067] The compatibilizer (C) in the present embodiment preferably has an amide bond. The method for imparting an amide bond to the compatibilizer (C) in the present embodiment is not particularly limited. However, in the step of producing a compound containing at least one selected from the group consisting of the above-mentioned olefin skeleton and aromatic ring skeleton, a method of reacting with polyamide and / or their copolymers, and / or their combinations, etc., a method of mixing pellets of a compound containing at least one selected from the group consisting of the above-mentioned olefin skeleton and aromatic ring skeleton with polyamide and / or their copolymers, and / or their combinations, etc., and kneading and reacting with an extruder, etc. can be mentioned.

[0068] The compatibilizer (C) in the present embodiment preferably has a reactive functional group capable of reacting with the terminal group and / or the amide group in the main chain of the polyamide resin (A).

[0069] Examples of the reactive functional group include a carboxy group, an acid anhydride group, an epoxy group, an oxazoline group, an amino group, an isocyanate group, maleic acid, itaconic acid, citraconic acid, allyl succinic acid, cyclohex-4-ene-1,2-dicarboxylic acid, 4-methylenecyclohex-4-ene-1,2-dicarboxylic acid, bicyclo(2,2,1)hept-5-ene-2,3-dicarboxylic anhydride, x-methylbicyclo(2,2,1)hept-5-ene-2,2-dicarboxylic acid, alkyl (methacrylate) acrylate (methyl acrylate), etc.

[0070] The method for imparting a reactive functional group to the compatibilizer (C) in the present embodiment is not particularly limited. However, in the step of producing a compound containing at least one selected from the group consisting of the above-described olefin skeleton and aromatic ring skeleton, a method of reacting a compound having the reactive functional group, a method of mixing pellets of a compound containing at least one selected from the group consisting of the above-described olefin skeleton and aromatic ring skeleton with a compound having the reactive functional group, etc., and kneading and reacting them with an extruder or the like can be mentioned.

[0071] It is more preferable that the compatibilizer (C) in the present embodiment contains at least one selected from the group consisting of reactive functional groups having structural units derived from amide bonds and carboxylic acid anhydrides. It is even more preferable that it contains at least one selected from the group consisting of structural units derived from amide bonds and maleic acid. It is particularly preferable that it has an amide bond, and it is most preferable that it has an amide bond in the side chain.

[0072] From the viewpoint of further excellent sliding properties, mechanical properties, heat resistance, long-term heat resistance, moldability, processability, etc., the compatibilizer (C) preferably contains at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton, an amide bond, and a reactive functional group having a structural unit derived from a carboxylic acid anhydride. More preferably, the component (C) has at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton in the main chain, and contains at least one selected from the group consisting of an amide bond and a structural unit derived from maleic acid in the main chain or side chain. Even more preferably, the component (C) has only one selected from the group consisting of an olefin skeleton and a styrene skeleton in the main chain, and has an amide bond in the main chain or side chain. Particularly preferably, the component (C) has an olefin skeleton in the main chain and an amide bond in the side chain. Most preferably, the component (C) is a graft copolymer having an olefin skeleton in the main chain and an amide bond in the side chain.

[0073] A graft copolymer having an olefin skeleton in the main chain and an amide bond in the side chain can be obtained, for example, by the reaction between the residue of the unsaturated monomer in the main chain part and the terminal of the skeleton having an amide bond.

[0074] Examples of the unsaturated monomer include, but are not limited to, unsaturated epoxides, unsaturated carboxylic anhydrides, salts or esters of unsaturated carboxylic acids, vinyl esters of saturated carboxylic acids, and the like.

[0075] Examples of the unsaturated carboxylic anhydride include, but are not limited to, maleic acid, itaconic acid, citraconic acid, allyl succinic acid, cyclohex-4-ene-1,2-dicarboxylic acid, 4-methylenecyclohex-4-ene-1,2-dicarboxylic acid, bicyclo(2,2,1)hept-5-ene-2,3-dicarboxylic anhydride, and x-methylbicyclo(2,2,1)hept-5-ene-2,2-dicarboxylic acid.

[0076] Examples of the salt or ester of the unsaturated carboxylic acid include, but are not limited to, alkyl (meth)acrylate (methyl acrylate), and the like.

[0077] Examples of the vinyl ester of the saturated carboxylic acid include, but are not limited to, vinyl acetate, and the like.

[0078] In the polyamide resin composition of the present embodiment, from the viewpoint of further improving the compatibility between the component (A) and the component (B) and further improving the sliding properties, mechanical properties, heat resistance, long-term heat resistance, moldability, processability, etc., the component (C) is preferably a graft copolymer, and more preferably a graft copolymer having an olefin skeleton in the main chain and an amide bond in the side chain.

[0079] As the component (C), known ones can be used, and commercially available products may also be used.

[0080] [Manufacturing method of component (C)] The component (C) can be produced using a masterbatch prepared by previously melt-kneading at least one compound selected from, for example, a compound having at least one reactive functional group capable of reacting with the terminal group and / or the amide group in the main chain of the polyamide resin (A), and a compound having at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton (for example, a thermoplastic resin such as a polyamide resin).

[0081] Alternatively, as the component (C), a masterbatch prepared by previously melt-kneading a precursor of a graft copolymer having an unsaturated monomer in the skeleton and a thermoplastic resin having a reactive functional group with an unsaturated monomer can also be used.

[0082] Alternatively, when melt-kneading the component (A) and the component (B) during the production of the polyamide resin composition of the present embodiment, a graft copolymer precursor having an unsaturated monomer in the skeleton is blended and reacted with the component (A) to obtain the component (C). That is, by melt-kneading a composition containing the component (A) and the component (B) with an extruder or the like, a polyamide resin composition containing the component (A), the component (B), and the component (C) can also be obtained.

[0083] (Content ratio of component (C)) In the polyamide resin composition of the present embodiment, the content ratio of the component (C) is preferably 0.01 to 15 parts by mass, more preferably 0.05 to 15 parts by mass, still more preferably 0.1 to 12 parts by mass, even more preferably 0.2 to 10 parts by mass, and most preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the polyamide resin (A). When it is above the lower limit value, sliding properties, moldability, processability, heat resistance, etc. are effectively exhibited, and when it is below the upper limit value, sliding properties, mechanical properties, heat resistance, long-term heat resistance, moldability, processability, etc. are improved.

[0084] (A) Polyamide resin and (B) A compatibilizer (C) is blended to improve the compatibility of the polyolefin-based graft copolymer having an aromatic ring-containing polymer in the side chain, thereby further improving the sliding properties, mechanical properties, heat resistance, long-term heat resistance, moldability, and processability.

[0085] (Mass ratio of component (C) to component (B) ((C) / (B)) When component (C) has an olefin skeleton, the mass ratio of component (C) to component (B) ((C) / (B)) is preferably from 0.01 to 2, more preferably from 0.05 to 0.9. When component (C) has an aromatic ring skeleton, the mass ratio of component (C) to component (B) ((C) / (B)) is preferably from 0.0001 to 1, more preferably from 0.05 to 0.9, and even more preferably from 0.1 to 0.4. When the mass ratio of component (C) to component (B) is within the above range, the sliding properties, mechanical properties, heat resistance, long-term heat resistance, moldability, and processability are further improved.

[0086] (Copper compound) The copper compounds used in this embodiment are not limited to the following. For example, copper halides, copper acetate, copper propionate, copper benzoate, copper adipate, copper terephthalate, copper isophthalate, copper salicylate, copper nicotinate, copper stearate, etc., and copper complex salts coordinated with chelating agents such as ethylenediamine and ethylenediaminetetraacetic acid can be mentioned. These copper compounds may be used alone or in combination of two or more.

[0087] Among them, as the copper compound, copper iodide, cuprous bromide, cupric bromide, cuprous chloride, and copper acetate are preferable, and copper iodide is more preferable. From the viewpoint of sliding properties, the copper compound is preferably used in a masterbatch form with a halide of a metal selected from the group consisting of alkali metals and alkaline earth metals.

[0088] (Blending amount of copper compound) The compounding amount of the copper compound is 0.01 to 5 parts by mass, preferably 0.01 to 4 parts by mass, more preferably 0.03 to 3 parts by mass, and even more preferably 0.03 to 1.5 parts by mass with respect to 100 parts by mass of the component (A). By setting the compounding amount of the copper compound within the above range, the heat aging resistance can be improved, and copper precipitation and corrosion can be suppressed. Furthermore, the effects of reducing the friction coefficient and wear depth are exhibited.

[0089] (Halide of a metal selected from the group consisting of alkali metals and alkaline earth metals) Examples of the halide of a metal selected from the group consisting of alkali metals and alkaline earth metals (hereinafter may be abbreviated as "metal halide") used in this embodiment include potassium iodide, sodium iodide, potassium bromide, potassium chloride, sodium chloride, etc. Among these, potassium iodide is preferable. These metal halides may be used alone or in combination of two or more.

[0090] (Compounding amount of metal halide) The compounding amount of the metal halide is 0.05 to 5 parts by mass, preferably 0.1 to 4 parts by mass, and more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the (A) polyamide resin. By setting the compounding amount of the metal halide within the above range, the heat aging resistance can be improved, and copper precipitation and corrosion can be suppressed. Furthermore, the effects of reducing the friction coefficient and wear depth are exhibited.

[0091] (Particle diameters of copper compound and metal halide) In addition, the maximum particle diameters of the copper compound and the metal halide to be compounded are not particularly limited, but both are preferably 50 μm or less, more preferably 20 μm or less, and even more preferably 10 μm or less. On the other hand, the maximum particle diameters of the copper compound and the metal halide to be compounded can be 10 nm or more.

[0092] In the present invention, the particle size refers to the biaxial average diameter, that is, the average value of the minor axis and the major axis. Here, the minor axis and the major axis are the short side and the long side of the circumscribed rectangle with the minimum area circumscribing the particle, respectively. The measurement of the maximum particle size of the copper compound and the metal halide can be determined on a number basis by observing at least 50 particles using a scanning electron microscope (SEM).

[0093] By setting the maximum particle size within the above range, even under the condition that the moisture content in the (A) polyamide resin is low, the copper compound and the metal halide tend to be finely dispersed in the (A) polyamide resin. As a result, metal precipitation and corrosion are suppressed, and the toughness, heat resistance aging property, appearance, and color tone of the obtained polyamide resin composition are further improved, and the friction coefficient and wear depth tend to be further reduced.

[0094] (Molar ratio of halogen to copper) When the copper compound and the metal halide are made into a masterbatch, the molar ratio of halogen to copper (halogen / copper) in the masterbatch is preferably 3 to 30, more preferably 4 to 25, and still more preferably 5 to 23. By setting the molar ratio of halogen to copper to be equal to or higher than the lower limit value, copper precipitation and metal corrosion tend to be more suppressed. Also, by setting the molar ratio of halogen to copper to be equal to or lower than the upper limit value, corrosion of the screw of the molding machine and the like is more suppressed without impairing mechanical properties such as toughness.

[0095] (Organic compound having at least one amide group) In the present embodiment, an organic compound (excluding polyamide) having at least one amide group can be present in the masterbatch.

[0096] By including an organic compound having at least one amide group (excluding polyamides), it tends to be possible to prevent copper compounds and metal halides from dissolving in the moisture in component (A) and forming complexes during melt-kneading. Further, without adversely affecting component (A), it tends to be possible to stabilize the dispersion of copper compounds and metal halides in component (A) and prevent precipitation and deterioration.

[0097] The organic compound having at least one amide group used in this embodiment is a compound having at least one amide group in the molecular chain. Examples of the organic compound having at least one amide group include, but are not limited to, monoamides, substituted amides, methylol amides, and bisamides.

[0098] Monoamides are represented by the general formula R-CONH2 (where R is a saturated aliphatic, unsaturated aliphatic, aromatic group having 8 to 30 carbon atoms, or a group in which a part of -H thereof is substituted with -OH).

[0099] Examples of monoamides include, but are not limited to, lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, linolenic acid amide, etc.

[0100] Substituted amides are represented by the general formula R 1 -CONH-R 2 (where R 1 and R 2 are each independently a saturated aliphatic, unsaturated aliphatic, aromatic group having 8 to 30 carbon atoms, or a group in which a part of -H thereof is substituted with -OH).

[0101] Examples of the replacement amides include, but are not limited to, N-lauryl laurate amide, N-palmitoyl palmitic acid amide, N-stearyl stearic acid amide, N-oleyl oleic acid amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, N-oleyl palmitic acid amide, N-stearyl 12-hydroxystearic acid amide, N-oleyl 12-hydroxystearic acid amide, and the like.

[0102] The methylol amides are represented by the general formula R-CONHCH2OH (wherein R is a saturated aliphatic, unsaturated aliphatic, aromatic group having 8 to 30 carbon atoms, or a group in which a part of -H thereof is substituted by -OH).

[0103] Examples of the methylol amides include, for example, methylol stearic acid amide, methylol behenic acid amide, and the like.

[0104] The bisamides are represented by the general formula (R-CONH)2(CH2) n (wherein R is a saturated aliphatic, unsaturated aliphatic, aromatic group having 8 to 30 carbon atoms, or a group in which a part of -H thereof is substituted by -OH; and n is 1 to 8).

[0105] Examples of the bisamides include, but are not limited to, methylene bislauric amide, methylene bislauric amide, methylene bishydroxystearic amide, ethylene biscaprylic amide, ethylene bislauric amide, ethylene bisstearic amide, ethylene bisisostearic amide, ethylene bishydroxystearic amide, ethylene bisbehenic amide, hexamethylene bisstearic amide, hexamethylene bisbehenic amide, hexamethylene bishydroxystearic amide, butylene bishydroxystearic amide, N,N'-distearyl adipic amide, N,N'-distearyl sebacic amide, methylene bisoleic amide, ethylene bisoleic amide, ethylene biserucic amide, hexamethylene bisoleic amide, N,N'-dioleyl adipic amide, N,N'-dioleyl sebacic amide, m-xylylene bisstearic amide, N,N'-distearyl isophthalic amide, and the like.

[0106] These organic compounds having at least one amide group may be used alone or in combination of two or more.

[0107] Among these, bisamides are preferred.

[0108] (Blending amount of the organic compound having at least one amide group) The blending amount of the organic compound having at least one amide group is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5.0 parts by mass, and still more preferably 1.0 to 4.0 parts by mass with respect to 100 parts by mass of the (A) polyamide resin. By setting the blending amount of the organic compound having at least one amide group within the above range, the dispersibility of the copper compound and the metal halide in the (A) component is further improved, the heat aging resistance is further improved, and as a result, copper precipitation and metal corrosion are more suppressed, and the friction coefficient and the wear depth tend to be further reduced.

[0109] (Moisture content of the master patch) The moisture content of the masterbatch is preferably 0.06 to 1.0% by mass, more preferably 0.10 to 0.75% by mass, and even more preferably 0.15 to 0.75% by mass, based on the total mass of the masterbatch.

[0110] The moisture in the masterbatch may exist as moisture bound to polyamide molecules. It may also be moisture adhering to the surface of the masterbatch, for example, the surface of masterbatch pellets or masterbatch powder.

[0111] By setting the moisture content within the above range, aggregation of copper compounds and metal halides tends to be more suppressed. As a result, mechanical properties such as toughness and heat aging resistance are further improved, copper precipitation and metal corrosion are more suppressed, and the friction coefficient and wear depth tend to be further reduced.

[0112] The moisture content of the masterbatch can be adjusted by controlling the degree of vacuum in the extruder, the immersion time in the strand bath during cooling, the immersion length, or the amount of water spray. In this embodiment, the moisture content of the masterbatch can be measured by a coulometric titration method (Karl Fischer method) using a moisture vaporization device (for example, VA-06 type manufactured by Mitsubishi Chemical Corporation).

[0113] (Moisture content of polyamide resin composition) The moisture content of the polyamide resin composition in this embodiment is preferably 0.01 to 1% by mass, more preferably 0.03 to 0.5% by mass, and even more preferably 0.05 to 0.30% by mass, based on the total mass of the polyamide resin composition.

[0114] The moisture in the polyamide resin composition may exist as moisture bound to polyamide molecules, or it may be moisture adhering to the surface of the polyamide resin composition, for example, the surface of pellets or powder. From the viewpoint of improving the effects of the present invention, it is more preferable that the moisture exists as moisture bound to polyamide molecules.

[0115] By setting the moisture content of the polyamide resin composition within the above range, aggregation of copper compounds and metal halides is further suppressed. As a result, mechanical properties such as toughness are further improved, heat aging resistance is further improved, copper precipitation and metal corrosion are further suppressed, and the friction coefficient and wear depth tend to be further reduced. The moisture content of the polyamide resin composition can be adjusted by controlling the degree of vacuum in the extruder, the immersion time in the strand bath during cooling, the immersion length, or the amount of water spray. In this embodiment, the moisture content of the polyamide resin composition can be measured by a coulometric titration method (Karl Fischer method) using a moisture vaporization device (for example, VA-06 type manufactured by Mitsubishi Chemical Corporation).

[0116] (Hindered phenol-based heat stabilizer) It is preferable to further add a heat stabilizer to the polyamide resin composition. The heat stabilizer is not particularly limited, and examples thereof include phenolic stabilizers such as hindered phenol compounds, phosphite stabilizers, hindered amine stabilizers, triazine stabilizers, and sulfur stabilizers. Preferably, it is a hindered phenol compound which is a phenolic stabilizer. These heat stabilizers also exhibit an effect in reducing the friction coefficient and wear depth.

[0117] The content of the hindered phenol-based heat stabilizer is preferably 0.01 to 5 parts by mass, more preferably 0.015 to 3 parts by mass, based on 100 parts by mass of the component (A).

[0118] (Filler) The polyamide resin composition can further contain a filler as needed. The filler is not limited to the following, and examples thereof include fiber fillers such as carbon fiber, glass fiber, calcium silicate fiber, potassium titanate fiber, aluminum borate fiber, wollastonite, and carbon nanotube.

[0119] Among these, carbon fiber and glass fiber are preferable. From the viewpoint of increasing the strength of the polyamide resin composition, glass fiber is preferable, and from the viewpoint of improving slidability, carbon fiber is preferable.

[0120] As the carbon fiber, for example, either polyacrylonitrile (PAN)-based carbon fiber or pitch-based carbon fiber can be used. From the viewpoint of mechanical properties, it is preferable to use PAN-based carbon fiber.

[0121] The above-described fibrous filler may be used alone as one kind, or may be used in combination of two or more kinds.

[0122] From the viewpoint of improving sliding characteristics, the fiber filler is preferably 1 to 50 parts by mass, more preferably 1 to 30 parts by mass, still more preferably 3 to 20 parts by mass, and particularly preferably 5 to 10 parts by mass with respect to 100 parts by mass of the component (A).

[0123] From the viewpoint of productivity, it is preferable to add carbon fiber in the form of short fibers of about 3 mm to 10 mm to the extruder by melt kneading. At that time, from the viewpoint of preventing breakage of the carbon fiber, it is preferable to add the carbon fiber from a side feeder.

[0124] From the viewpoint of affinity with the polyamide resin (A), carbon fiber preferably has a urethane-based sizing agent, maleic anhydride-based sizing agent, acrylic-based sizing agent, or polyamide-based sizing agent applied thereto.

[0125] From the viewpoints of physical properties and slidability, the carbon fiber preferably has a diameter of 5 μm or more and 10 μm or less.

[0126] (Molding improver) To the polyamide resin composition, a molding improver may be added as necessary within a range not impairing the object of the present invention.

[0127] The molding improver is not particularly limited, and examples thereof include higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides.

[0128] Examples of the higher fatty acid include, but are not limited to, saturated or unsaturated, linear or branched aliphatic monocarboxylic acids having 8 to 40 carbon atoms, such as stearic acid, palmitic acid, behenic acid, erucic acid, oleic acid, lauric acid, and montanic acid. Among these, stearic acid and montanic acid are preferred.

[0129] The metal salt of higher fatty acid is the metal salt of the above-mentioned higher fatty acid.

[0130] As the metal element of the metal salt, elements of Groups 1, 2, and 3 of the periodic table of elements, zinc, aluminum, etc. are preferred, and elements of Groups 1 and 2 such as calcium, sodium, potassium, and magnesium, and aluminum, etc. are more preferred.

[0131] Examples of the metal salt of higher fatty acid include, but are not limited to, metal salts of stearic acid such as calcium stearate, aluminum stearate, zinc stearate, and magnesium stearate, metal salts of montanic acid such as calcium montanate and sodium montanate, and metal salts of palmitic acid such as calcium palmitate. Among these, the metal salts of montanic acid and stearic acid are preferred.

[0132] The higher fatty acid ester is an esterified product of the above-mentioned higher fatty acid and alcohol. An ester of an aliphatic carboxylic acid having 8 to 40 carbon atoms and an aliphatic alcohol having 8 to 40 carbon atoms is preferred.

[0133] Examples of the aliphatic alcohol include, but are not limited to, stearyl alcohol, behenyl alcohol, and lauryl alcohol.

[0134] Examples of the higher fatty acid ester include stearyl stearate, behenyl behenate, etc.

[0135] A higher fatty acid amide is an amide compound of the above higher fatty acid. Examples of the higher fatty acid amide include, but are not limited to, stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearyl amide, ethylene bisoleyl amide, N-stearyl stearyl amide, N-stearyl erucic acid amide, and the like.

[0136] These higher fatty acids, higher fatty acid metal salts, higher fatty acid esters, and higher fatty acid amides may each be used alone or in combination of two or more.

[0137] (Colorant) A colorant may be added to the polyamide resin composition as necessary within a range not impairing the object of the present invention. The colorant is not particularly limited, and examples thereof include dyes such as nigrosine, pigments such as titanium oxide and carbon black; metal particles such as aluminum, colored aluminum, nickel, tin, copper, gold, silver, platinum, iron oxide, stainless steel, and titanium; mica-based pearl pigments, metallic pigments such as color graphite, and the like.

[0138] (Other resins) Other resins may be added to the polyamide resin composition as necessary within a range not impairing the object of the present invention. Such resins are not particularly limited, and examples thereof include thermoplastic resins and rubber components described later.

[0139] Examples of the thermoplastic resin include, but are not limited to, polystyrene-based resins such as atactic polystyrene, isotactic polystyrene, syndiotactic polystyrene, AS (acrylonitrile-styrene) resin, and ABS (acrylonitrile-butadiene-styrene) resin; acrylic resins such as polyacrylic acid, polyacrylic acid ester, and polymethyl methacrylate; halogen-containing vinyl compound-based resins such as polyvinyl chloride and polyvinylidene chloride. These thermoplastic resins may be used alone or in combination of two or more.

[0140] Examples of the rubber component include natural rubber, polybutadiene, polyisoprene, polyisobutylene, neoprene, polysulfide rubber, thiokol rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, styrene-butadiene block copolymer (SBR), hydrogenated styrene-butadiene block copolymer (SEB), styrene-butadiene-styrene block copolymer (SBS), hydrogenated styrene-butadiene-styrene block copolymer (SEBS), styrene-isoprene block copolymer (SIR), hydrogenated styrene-isoprene block copolymer (SEP), styrene-isoprene-styrene block copolymer (SIS), hydrogenated styrene-isoprene-styrene block copolymer (SEPS), styrene-butadiene random copolymer, hydrogenated styrene-butadiene random copolymer, styrene-ethylene-propylene random copolymer, styrene-ethylene-butylene random copolymer, ethylene-propylene copolymer (EPR), ethylene-(1-butene) copolymer, ethylene-(1-hexene) copolymer, ethylene-(1-octene) copolymer, ethylene-propylene-diene copolymer (EPDM), butadiene-acrylonitrile-styrene-core shell rubber (ABS), methyl methacrylate-butadiene-styrene-core shell rubber (MBS), methyl methacrylate-butyl acrylate-styrene-core shell rubber (MAS), octyl acrylate-butadiene-styrene-core shell rubber (MABS), alkyl acrylate-butadiene-acrylonitrile-styrene core shell rubber (AABS), butadiene-styrene-core shell rubber (SBR), and core shell type such as siloxane-containing core shell rubber including methyl methacrylate-butyl acrylate siloxane. These rubber components may be used alone or in combination of two or more.

[0141] The polyamide resin composition of the present invention is not particularly limited as long as it is used in applications where mechanical properties and sliding properties are required. However, it can be widely used as a raw material for sliding parts such as electrical and electronic parts, automotive parts, building parts, and industrial parts, and molded products can be obtained by molding them into electrical and electronic parts, automotive parts, building parts, or sliding parts. Examples of the sliding parts include those generally used as injection molded articles such as bearings, gears, door checkers, and chain guide parts.

[0142] [Method for producing polyamide resin composition] The polyamide resin composition of the present embodiment can be obtained by mixing and kneading (A) a polyamide resin, (B) a polyolefin-based graft copolymer having an aromatic ring polymer in the side chain, and (C) a compatibilizer, and, if necessary, a copper compound, a metal halide, and other components.

[0143] The copper compound and the metal halide are preferably masterbatch-prepared in advance and then melt-kneaded together with the components (A), (B), and (C). Alternatively, it is also preferable to masterbatch-prepare the copper compound, the metal halide, and the component (A) in advance and then melt-knead them together with the components (B) and (C). In addition, when producing the polyamide resin composition, when mixing and kneading the component (A), the copper compound and the metal halide, and other components, which are blended as necessary, the raw material of the component (C) may be blended and melt-kneaded in a twin-screw extruder to form the component (C).

[0144] [Masterbatch preparation process] The masterbatch is prepared by melt-kneading the copper compound and the metal halide. In addition to the copper compound and the metal halide, it is preferable to blend an organic compound having at least one amide group (excluding polyamide). In addition to the organic compound having at least one amide group (excluding polyamide), it is preferable to blend the component (A).

[0145] When blending the organic compound having at least one amide group (excluding polyamide) with the component (A), the copper compound, the metal halide, and the organic compound having at least one amide group (excluding polyamide) may be blended with the component (A) individually. Also, at least two of the three types of compounds may be premixed and then blended with the component (A), or at least two of the three types of compounds may be premixed, pulverized, and then blended with the component (A), or at least two of the three types of compounds may be premixed, pulverized, formed into tablets, and then blended with the component (A).

[0146] As a method for mixing the compounds, for example, known methods such as a method of mixing using any of a tumbler, a Henschel mixer, a Proshear mixer, a Nauta mixer, a flow jet mixer, etc. can be utilized.

[0147] As a method for pulverizing the compounds, known methods can be utilized. Examples of the method for pulverizing the compounds include a method of pulverizing using any of a hammer mill, a knife mill, a ball mill, a jaw crusher, a cone crusher, a roller mill, a jet mill, a mortar, etc.

[0148] As a method for forming the compounds into tablets, for example, known methods such as a compression granulation method, a tableting method, a dry extrusion granulation method, a melt extrusion granulation method, etc. can be utilized.

[0149] The apparatus for performing melt kneading is not particularly limited, and known apparatuses can be used. For example, melt kneaders such as a single-screw or twin-screw extruder, a Banbury mixer, and a mixing roll are preferably used. Among them, a twin-screw extruder is preferably used. Also, the apparatus for performing melt kneading may be equipped with a degassing mechanism (vent) apparatus and a side feeder facility.

[0150] The temperature of melt-kneading in this embodiment is preferably in the range from 1°C higher than the melting point or softening point determined by differential scanning calorimetry (DSC) measurement according to JIS K7121 of component (A) to 310°C, more preferably in the range from 10°C higher than the melting point or softening point to 300°C, and even more preferably in the range from 15°C higher than the melting point or softening point to 295°C. In this embodiment, the temperature of melt-kneading is the barrel set temperature of the extruder. The shear rate in the kneader is preferably about 100 (SEC -1 ) or more. Also, the average residence time during kneading is preferably about 1 to 15 minutes.

[0151] (Masterbatch, melt-kneading step of component (A), component (B), and component (C)) The polyamide resin composition of this embodiment is produced by melt-kneading the masterbatch, component (A), component (B), and component (C) together with other components that are blended as necessary. When component (A) is blended in the masterbatch, the polyamide resin composition of this embodiment is prepared by adding component (B) and component (C) to the masterbatch and melt-kneading them.

[0152] (Total mass of the copper compound and the metal halide) With respect to 100 parts by mass of polyamide resin (A), preferably, the total mass of the copper compound and the metal halide is 0.01 to 100 parts by mass, more preferably 0.05 to 20 parts by mass, and even more preferably 0.1 to 1 part by mass. By setting the total mass of the copper compound and the metal halide within the above range, precipitation of metallic copper and metal corrosion in the extruder and molding machine are more suppressed, and the stability during processing tends to be more improved. As a result, without deteriorating the mechanical properties of the product, the heat aging resistance tends to be more improved, the friction coefficient and wear depth tend to be more reduced, and the change in appearance color due to water absorption is more suppressed.

[0153] The blending ratios of component (B) and component (C) with respect to 100% by mass of polyamide resin (A) are as described above.

[0154] The melt-kneading step is preferably carried out using various commonly used extruders such as single-screw or twin-screw extruders. From the viewpoints of productivity, versatility, etc., it is particularly preferable to carry out using a twin-screw extruder. At this time, the melt-kneading temperature depends on the type of component (A), but it is preferable to adjust the temperature of the molten resin discharged from the extruder discharge port to a temperature equal to or higher than the melting points of components (A), (B), and (C). By setting the melt-kneading temperature within the above range, it is difficult to cause extrusion kneading defects, and fine dispersion of components (B) and (C) becomes possible.

[0155] In the case of a twin-screw extruder, it is preferable that the extruder screw has a kneading zone in which at least two or more kneading disks are combined. The kneading zone is a region that imparts high shear while suppressing the progress of the molten resin in the extrusion direction so that kneading is effectively carried out.

[0156] In the melt-kneading step, from the most upstream supply port of the twin-screw extruder, components (A), (B), (C), and the masterbatch (copper compound and metal halide), and, if necessary, other components (hindered phenol-based heat stabilizer, etc.) are supplied, and melt-kneaded in the first kneading zone to obtain a first melt-kneaded product. Further, if necessary, a fibrous filler is supplied from a side supply port provided on the downstream side of the first kneading zone, and it is preferable to disperse the non-molten fibrous filler in the first melt-kneaded product in a second kneading zone provided on the downstream side of the side supply port.

[0157] It is desirable to set each condition (barrel temperature, screw rotation speed, discharge amount, etc.) of the extruder so that the resin temperature of the polyamide resin composition discharged from the extruder outlet after the melt-kneading step is higher than the crystallization temperature of component (A) and is 280°C or higher and 400°C or lower. By setting the temperature of the polyamide resin composition at the discharge port to 280°C or higher and 400°C or lower, components (A), (B), and (C) can be more finely dispersed. As a result, a polyamide resin composition excellent in sliding properties and mechanical properties can be obtained.

[0158] The temperature of the polyamide resin composition is preferably measured, for example, by directly contacting the detection part of a commercially available thermocouple thermometer with the molten polyamide resin composition discharged from the extruder outlet. The temperature setting of the extruder for achieving the temperature of the polyamide resin composition is preferably 280°C or higher and 400°C or lower.

[0159] By molding the polyamide resin composition, a molded body of the polyamide resin composition of the present embodiment can be obtained. The method for obtaining the molded body is not particularly limited. For example, known molding methods such as extrusion molding, injection molding, vacuum molding, blow molding, injection compression molding, decorative molding, molding with other materials, gas-assisted injection molding, foam injection molding, low-pressure molding, ultra-thin-wall injection molding (ultra-high-speed injection molding), and in-mold composite molding (insert molding, outsert molding) can be used.

[0160] When molding the polyamide resin composition of the present embodiment, the set temperature of the molding machine is preferably in the range from 5°C higher than the melting point of component (A) used to 310°C, more preferably in the range from 10°C higher than the melting point to 300°C, and even more preferably in the range from 15°C higher than the melting point to 295°C. By setting the set temperature of the molding machine within the above temperature range, the polyamide resin composition can be effectively kneaded during molding, and components (B) and (C) in the polyamide resin composition can be more finely dispersed.

[0161] The polyamide resin composition of the present invention is not particularly limited as long as it is used in applications where mechanical properties and sliding properties are required, but it can be widely used as a raw material for sliding parts such as electrical and electronic parts, the robot industry, automotive parts, building parts, and industrial parts. Examples of sliding parts include, for example, bearings, gears, door checkers, and chain guide parts, which are generally injection molded products.

Examples

[0162] Hereinafter, the present invention will be described in detail with specific examples and comparative examples, but the present invention is not limited to the following examples. The raw materials used in the examples and comparative examples, and the measurement methods for physical property tests, etc. are as follows.

[0163] ((A) Polyamide resin) (A-1) Polyamide resin: Polyamide 66 (Production Example 1), melting point 265 °C (A-2) Polyamide resin: Polyamide 66, 1200-321 (trade name), manufactured by Asahi Kasei Corporation, melting point 265 °C (A-3) Polyamide resin: Polyamide 66, 1500-X31 (trade name), manufactured by Asahi Kasei Corporation, melting point 265 °C (A-4) Polyamide resin: Stanyl TW341-J, manufactured by DSM Corporation, melting point 295 °C (A-5) Polyamide resin: SF1013A, manufactured by UBE Corporation, melting point 223 °C (A-6) Polyamide resin: Crystalline semi-aromatic polyamide resin (Production Example 4), melting point 336 °C

[0164] ((B) Polyolefin-based graft copolymer having a polymer with an aromatic ring in the side chain) (B-1): MODIPER-A1100, manufactured by NOF Corporation, polyethylene-polystyrene-based graft copolymer (B-2): MODIPER-A1401, manufactured by NOF Corporation, polyethylene-polystyrene / vinyl-based graft copolymer

[0165] ((C) Compatibilizer) (C1-1) APOLHYA LP91: manufactured by Arkema Corporation, polyolefin-polyamide-based polymer (C1-2) Graft copolymer: polystyrene-polyamide-based polymer (Production Example 3) (C2-1) FUSABOND N525: manufactured by The Dow Chemical Company, maleic anhydride-modified polyolefin-based polymer (C2-2) FUSABOND MN493D: manufactured by The Dow Chemical Company, maleic anhydride-modified polyolefin-based polymer (C2-3) FUSABOND N416: Manufactured by The Dow Chemical Company, maleic anhydride-modified polyolefin polymer (C2-4) ToughTech M1943: Manufactured by Asahi Kasei Corporation, styrene-based thermoplastic elastomer (C3-1) XIBOND 180: Manufactured by Polyscope, styrene-maleic anhydride copolymer (C3-2) XIBOND 120: Manufactured by Polyscope, styrene-maleic anhydride copolymer (C3-3) XIBOND 280: Manufactured by Polyscope, styrene-maleic anhydride copolymer (C3-4) Maleic anhydride-modified polyphenylene ether (m-PPE) (manufactured by Asahi Kasei Corporation) (molecular weight: 54,000)

[0166] ((D) Polyolefin copolymer) (D-1) ENGAGE 8180: Manufactured by The Dow Chemical Company Japan, ethylene-octene copolymer

[0167] · Copper iodide: Copper(I) iodide, manufactured by Wako Pure Chemical Industries, Ltd. · Potassium iodide: Potassium iodide, manufactured by Wako Pure Chemical Industries, Ltd. · Hindered phenol-based heat stabilizer: Manufactured by BASF, IRGANOX 1098 · Spreading agent: Sanyo Chemical Industries, Ltd., PEG400 · Azine dye: Nigrosine, NUBIAN (registered trademark) BLACK TH-807 manufactured by Orient Chemical Industries Co., Ltd.

[0168] (Production Example 1) Preparation of polyamide 66 ((A-1) polyamide resin) 15,000 g of an equimolar salt of adipic acid and hexamethylenediamine, and 0.5 mol% excess adipic acid with respect to the equimolar salt components were dissolved in 15,000 g of distilled water to obtain a 50 mass% aqueous solution of the raw material monomers. The obtained aqueous solution was put into an autoclave with an internal volume of 40 L, and the inside of the autoclave was replaced with nitrogen. This aqueous solution was stirred at a temperature of 110 to 150 °C, and water vapor was gradually removed to concentrate the solution to a concentration of 70 mass%. Thereafter, the internal temperature was raised to 220 °C. At this time, the pressure in the autoclave increased to 1.8 MPa. While gradually removing water vapor and maintaining the pressure at 1.8 MPa, the reaction was carried out for 1 hour until the internal temperature reached 270 °C. Thereafter, the pressure was reduced to atmospheric pressure over about 1 hour. After reaching atmospheric pressure, it was discharged in a strand shape from the lower nozzle, and water cooling and cutting were performed to obtain pellets. The obtained pellets were dried at 90 °C for 4 hours in a nitrogen stream. The relative viscosity of the obtained pellets in 98% sulfuric acid (measured by the method specified in JIS-K6920) was 2.71, the melting point (determined by differential scanning calorimetry (DSC) measurement according to JISK7121) was 265 °C, and the crystallization temperature (determined by differential scanning calorimetry (DSC) measurement according to JISK7121) was 220 °C.

[0169] (Production Example 2) Preparation of Masterbatch To 100 parts by mass of the (A-1) polyamide resin obtained in (Production Example 1), 1.5 parts by mass of copper iodide and 32.5 parts by mass of a 40 mass% aqueous solution of potassium iodide were added. The obtained mixture was melt-kneaded using a twin-screw extruder (manufactured by Plastic Engineering Laboratory, co-rotating twin-screw type, L / D = 60 (D = 30φ)) at a screw rotation speed of 100 rpm and a cylinder temperature of 280 °C to obtain a masterbatch containing the (A-1) polyamide resin, copper iodide, and potassium iodide.

[0170] (Production Example 3) Polystyrene-polyamide polymer 90 parts by mass of a polyamide resin and 10 parts by mass of a compatibilizer were added, and melt-kneaded using a twin-screw extruder (manufactured by Plastic Engineering Laboratory, co-rotating twin-screw type, L / D = 60 (D = 30φ)) at a screw rotation speed of 300 rpm and a cylinder temperature of 280°C to obtain a polystyrene-polyamide polymer formed by the reaction of 90 parts by mass of the polyamide resin and 10 parts by mass of the compatibilizer.

[0171] (Production Example 4) Crystalline semi-aromatic polyamide resin ((A-6) polyamide resin) A 50-liter rotary dryer was charged with 15 kg of polyamide 4T / polyamide 6T salt (39 / 61 mol / mol). After evacuating the rotary dryer to 50 mbar, the process of filling with nitrogen was repeated 5 times. While discharging the reaction water from the rotary dryer, the polyamide 4T / polyamide 6T salt was heated to a temperature of 220°C in 5 hours and then to 255°C in 15 hours. A low-nitrogen purge was used during the reaction. After cooling the product to 235°C in 19 hours and maintaining the temperature at 235°C, a mixture consisting of 650 kg of 1,6-hexamethylenediamine, 300 g of 1,4-butanediamine, and 1.0 kg of water was added over 7 hours. The reaction was continued at 235°C for an additional 29 hours, then the nitrogen flow was increased and the product was cooled to room temperature. A white powder was obtained.

[0172] [Molding Method] The pellets of the polyamide resin compositions obtained in the examples and comparative examples were molded into multi-purpose test pieces of type A according to ISO 3167 using an injection molding machine NEX50IV-5EG (manufactured by Nissei Plastic Industrial Co., Ltd., screw diameter 26 mm, injection volume 49 cm 3 ) with an injection + holding pressure time of 25 seconds, a cooling time of 15 seconds, a mold temperature of 80°C, and a cylinder temperature = (melting point of the polyamide resin + 30)°C.

[0173] [Measurement Method] The sliding properties, mechanical properties, moldability, and long-term heat resistance were measured and evaluated by the methods described below.

[0174] [Evaluation of Sliding Properties] (Coefficient of friction, wear depth) Using a reciprocating friction and wear tester (AFT-15MS type manufactured by Toyo Precision Co., Ltd.) and a SUS304 test piece (a 5-mm-diameter sphere) as the counter material, a sliding test was carried out at a linear velocity of 50 mm / sec, a reciprocating distance of 20 mm, a temperature of 23°C, and a humidity of 50%. Furthermore, a coefficient of friction test was carried out with a load of 4 kg and 10,000 reciprocating cycles. In addition, the maximum wear depth of the wear mark of the sample after the sliding test was measured with a surface roughness meter (Model 575A-30 manufactured by Toyo Precision Co., Ltd.).

[0175] As evaluation samples, test pieces of multi-purpose test piece A type were molded according to ISO 3167 under the conditions of Samples 1 to 3 described below. Since the injection speeds of Samples 1 to 3 were significantly different, the melt flow rate (shear rate) of the molten resin was also significantly different, and it was confirmed that the change in the morphological state of the polyolefin-based resin was significant. Sample conditions for evaluating a wide range of shear rates during processing were created.

[0176] Sample 1: It was carried out in the same manner as the aforementioned [molding method] except that the injection speed was 5 mm / s. Sample 2: It was carried out in the same manner as the aforementioned [molding method] except that the injection speed was 30 mm / s. Sample 3: It was carried out in the same manner as the aforementioned [molding method] except that the injection speed was 100 mm / s.

[0177] [Evaluation of mechanical properties] (Tensile test) Using the A-type test pieces molded from the compositions obtained in the examples and comparative examples under the conditions shown in [molding method], a tensile test was carried out in accordance with ISO 527 at a test speed of 50 mm / min, and the tensile strength (MPa) was measured. In addition, the ratio of the displacement amount of the chuck distance at the time of fracture to the chuck distance before the test was defined as the tensile elongation (%). Tensile elongation (%) = 100 × displacement amount at the fracture point (mm) / initial chuck distance (mm) In addition, the value obtained by dividing the tensile strength by the tensile elongation was defined as the tensile modulus (MPa). Tensile modulus of elasticity (MPa) = Tensile strength (MPa) / Tensile elongation

[0178] (Charpy impact strength) The A-shaped test pieces obtained by molding the compositions obtained in the examples and comparative examples under the conditions shown in [Molding method] were processed into 80×10×4 mm, and in accordance with ISO179, the notched Charpy impact strength (kJ / m 2 ) was measured.

[0179] (Heat distortion temperature (°C)) The A-shaped test pieces obtained by molding the compositions obtained in the examples and comparative examples under the conditions shown in [Molding method] were processed into 80×10×4 mm, and in accordance with ISO75 (JIS K7191) Method B (bending stress 0.45 MPa), the heat distortion temperature (°C) was measured.

[0180] (Tensile strength and heat aging resistance) Each multi-purpose test piece (Type A) was placed in an oven conforming to ISO188 and heated at 150 °C for 1500 hours each to conduct a heat aging test. After 1500 hours, each multi-purpose test piece (Type A) was taken out of the oven and cooled at 23 °C for 24 hours. Next, each multi-purpose test piece (Type A) after the heat aging test was subjected to a tensile test at a tensile speed of 50 mm / min in accordance with ISO527, and the tensile strength (MPa) after the heat aging test was measured. Then, using the formula shown below, the tensile strength retention rate (%) was calculated.

[0181] "Tensile strength retention rate (%)" = (Tensile strength (MPa) after heat aging test) / (Tensile strength (MPa) before heat aging test) × 100

[0182] [Moldability evaluation] Using the molding conditions described in [Molding method], continuous molding was performed. Then, based on Table 1 below, the number of continuous molding cycles was evaluated in a step-by-step manner on a scale of 1 to 5. In this evaluation, 5 is the best among the 5-level evaluations, and 1 is the worst result.

[0183]

Table 1

[0184] (Example 1) (A-1) Polyamide resin, (B-1) Polyolefin-based graft copolymer, (C1-1) Compatibilizer, were mixed in the compounding amounts described in Table 2 below, and supplied from the uppermost supply port of a twin-screw extruder with a screw diameter of 26 mm (manufactured by Coperion Corporation, trade name "ZSK26MC18"). Next, the barrel temperature of the extruder was set to (melting point of polyamide resin + 30) °C, and extrusion was carried out while melt-kneading at a screw rotation speed of 300 rpm to obtain pellets of the polyamide resin composition. Using the obtained pellets of the polyamide resin composition, test pieces were produced by the method described in [Molding Method], and evaluations were carried out by the methods described in [Measurement Method].

[0185] (Examples 2 to 5) Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1, except that the compounding amount of (C1-1) compatibilizer was increased as described in Table 2 below.

[0186] (Example 6) Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 5, except that the amount of (B-1) polyolefin-based graft copolymer was increased as described in Table 2 below.

[0187] (Example 7) Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 6, except that the compounding amount of (C1-1) compatibilizer was increased as described in Table 3 below.

[0188] (Example 8) Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1, except that the amounts of (B-1) polyolefin-based graft copolymer and (C1-1) compatibilizer were increased and decreased as described in Table 3 below.

[0189] (Example 9) (B-1) Instead of the polyolefin-based graft copolymer, pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 4, except that (B-2) the polyolefin-based graft copolymer was blended.

[0190] (Example 10) (C1-1) Instead of the compatibilizer, pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 4, except that (C1-2) the compatibilizer was blended.

[0191] (Examples 11 to 14) (A-1) Instead of the polyamide resin, pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 4, except that (A-2) to (A-5) polyamide resins were blended as described in Tables 3 and 4 below.

[0192] (Examples 15 to 17) (C1-1) Instead of the compatibilizer, pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 3, except that (C2-1) to (C2-3) compatibilizers were blended as described in Table 4 below.

[0193] (Example 18) (C1-1) Instead of the compatibilizer, (C2-4) the compatibilizer was blended and increased as described in Table 4 below. Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 3.

[0194] (Example 19) (C1-1) Instead of the compatibilizer, (C2-2) the compatibilizer was blended as described in Table 5 below. Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1.

[0195] (Example 20) (C1-1) Instead of the compatibilizer, (C3-1) the compatibilizer was blended and increased as described in Table 5 below. Pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1.

[0196] (Example 21) (C1-1) Instead of the compatibilizer, a (C3-2) compatibilizer was blended as described in Table 5 below, and pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1 except that the amount was increased as described in Table 5 below.

[0197] (Example 22) (C1-1) Instead of the compatibilizer, a (C3-3) compatibilizer was blended as described in Table 5 below, and pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1 except that the amount was increased as described in Table 5 below.

[0198] (Example 23) (C1-1) Instead of the compatibilizer, a (C3-4) compatibilizer was blended as described in Table 5 below, and pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 1 except that the amount was increased as described in Table 5 below.

[0199] (Example 24) (A-1) Polyamide resin, (B-1) polyolefin-based graft copolymer, (C1-1) compatibilizer, pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 4 except that 2 parts by mass of the masterbatch obtained in Production Example 2 was blended as copper iodide and potassium iodide. The total content of the (A-1) polyamide resin in the pellets included the (A-1) polyamide resin contained in the masterbatch and was 100 parts by mass.

[0200] (Example 25) (A-1) Polyamide resin, (B-1) polyolefin-based graft copolymer, (C1-1) compatibilizer, further 0.03 parts by mass of copper iodide, 0.26 parts by mass of potassium iodide, 0.03 parts by mass of a hindered phenol-based heat stabilizer and 0.03 parts by mass of a spreading agent were blended, and pellets of the polyamide resin composition were obtained and evaluated in the same manner as in Example 4.

[0201] (Example 26) (A-1) Polyamide resin, (B-1) Polyolefin-based graft copolymer, (C1-1) Compatibilizer, and further 40 parts by mass of (A-6) polyamide resin were blended. Then, except that the barrel temperature of the extruder was set to ((melting point of (A-6) polyamide resin)) °C and the mold temperature of the injection molding machine was set to 120 °C and the cylinder temperature was set to ((melting point of (A-6) polyamide resin)) °C, pellets of the polyamide resin composition were obtained in the same manner as in Example 4, and evaluation was carried out.

[0202] (Example 27) (A-1) Polyamide resin, (B-1) Polyolefin-based graft copolymer, (C1-1) Compatibilizer, and pellets of the polyamide resin composition were obtained in the same manner as in Example 4 except that 5 parts by mass of (A-5) polyamide resin was further blended, and evaluation was carried out.

[0203] (Comparative Examples 1, 2) (C) Compatibilizer was not blended, and pellets of the polyamide resin composition were obtained in the same manner as in Example 1 except that (B-1) polyolefin-based graft copolymer was blended as described in Table 6 below, and evaluation was carried out.

[0204] (Comparative Example 3) (B) Polyolefin-based graft copolymer was not blended, and pellets of the polyamide resin composition were obtained in the same manner as in Example 1 except that (C1-1) compatibilizer was blended as described in Table 7 below, and evaluation was carried out.

[0205] (Comparative Example 4) (B) Instead of the polyolefin-based graft copolymer, pellets of the polyamide resin composition were obtained in the same manner as in Example 4 except that (D-1) polyolefin-based copolymer was blended as described in Table 7 below, and evaluation was carried out.

[0206] (Comparative Example 5) (C1-1) Instead of the compatibilizer, (C3-2) compatibilizer was blended, and pellets of the polyamide resin composition were obtained in the same manner as in Comparative Example 3 except that the amount was reduced as described in Table 7 below, and evaluation was carried out.

[0207] (Comparative Example 6) (C1-1) Instead of the compatibilizer, (C2-4) compatibilizer was blended, and further (D-1) polyolefin copolymer was blended as shown in Table 7 below. Pellets of the polyamide resin composition were obtained in the same manner as in Comparative Example 3, and evaluation was carried out.

[0208] (Comparative Example 7) (C1-1) Instead of the compatibilizer, (C2-2) compatibilizer was blended. Pellets of the polyamide resin composition were obtained in the same manner as in Comparative Example 3, and evaluation was carried out.

[0209] [Table 2]

[0210] [Table 3]

[0211] [Table 4]

[0212] [Table 5]

[0213] [Table 6]

[0214] [Table 7]

[0215] From the results of the examples, the polyamide resin composition of the present invention was excellent in all of the sliding properties (coefficient of friction, wear depth), moldability, and long-term heat resistance and mechanical properties (tensile strength, elastic modulus, impact resistance, heat resistance). Among them, in particular, by combining both the (B) component and the (C) component as compared with the comparative examples, excellent sliding properties were obtained in all the results of Evaluation Samples 1 to 3. From this result, it was judged that a polyamide resin composition having excellent sliding properties stably was obtained without depending on the injection speed (shearing speed applied to the molten resin). Further, from the results in Examples 11 to 14, by combining both the (B) component and the (C) component, there was no limitation on the type of the (A) polyamide resin, and excellent results were obtained in all of the sliding properties (coefficient of friction, wear depth), moldability, and long-term heat resistance and mechanical properties (tensile strength, elastic modulus, impact resistance, heat resistance).

[0216] On the other hand, from the results of the comparative examples, although polyamide resin compositions of the comparative examples excellent in some properties can be obtained, the results were inferior in the balance of sliding properties, long-term heat resistance, moldability, and mechanical properties. Among them, in particular, the sliding properties were significantly inferior as compared with the examples, and the sliding properties changed significantly depending on the sample conditions. Further, in Comparative Examples 1 and 2 in which the (C) component was not blended, all the properties were inferior, and when injection molding was carried out from the viewpoint of moldability, leakage of the molten resin occurred from the tip of the nozzle of the injection molding machine, making continuous injection molding difficult and resulting in low industrial applicability. Also, in Comparative Examples 3 to 7 in which the (B) component was not blended, the sliding properties were remarkably inferior.

Industrial Applicability

[0217] Since the polyamide resin composition of the present invention is excellent in sliding properties and mechanical properties, it has applicability in the fields of automobiles, electric and electronic fields, mechanical and industrial fields, office equipment fields, aviation and space fields, etc.

Claims

1. (A) A polyamide resin, (B) A polyolefin graft copolymer having a polymer with an aromatic ring in the side chain, and (C) A compatibilizer, In a polyamide resin composition containing, Furthermore, based on 100 parts by mass of the (A) polyamide resin, it contains 0.01 to 5 parts by mass of a copper compound and 0.05 to 5 parts by mass of a halide of a metal selected from the group consisting of alkali metals and alkaline earth metals. A polyamide resin composition.

2. The (C) compatibilizer contains at least one selected from the group consisting of an olefin skeleton and an aromatic ring skeleton. The polyamide resin composition according to Claim 1.

3. The content of the (B) polyolefin graft copolymer having a polymer with an aromatic ring in the side chain with respect to 100 parts by mass of the (A) polyamide resin is 1 to 15 parts by mass, and the content of the (C) compatibilizer is 1 to 15 parts by mass. The polyamide resin composition according to Claim 1.

4. The (C) compatibilizer contains at least an olefin skeleton. The polyamide resin composition according to Claim 2.

5. The mass ratio (C) / (B) of the (C) compatibilizer to the (B) polyolefin graft copolymer having a polymer with an aromatic ring in the side chain is 0.01 to 2. The polyamide resin composition according to Claim 4.

6. The (C) compatibilizer contains at least an aromatic ring skeleton. The polyamide resin composition according to Claim 2.

7. The mass ratio (C) / (B) of the (C) compatibilizer to the (B) polyolefin graft copolymer having a polymer with an aromatic ring in the side chain is 0.001 to 1. The polyamide resin composition according to Claim 6.

8. The (C) compatibilizer has at least a reactive functional group with the (A) polyamide resin. The polyamide resin composition according to Claim 6.

9. The reactive functional group contains a structural unit derived from a carboxylic anhydride. The polyamide resin composition according to Claim 8.

10. The (C) compatibilizer has at least an amide bond in the side chain. The polyamide resin composition according to Claim 1.

11. The (B) polyolefin graft copolymer having a polymer with an aromatic ring in the side chain has at least polyethylene in the main chain. The polyamide resin composition according to Claim 1.

12. A molded body formed by molding the polyamide resin composition according to any one of Claims 1 to 11.

13. A sliding member made of the polyamide resin composition according to any one of claims 1 to 11.

14. (A) A polyamide resin, (B) A polyolefin-based graft copolymer having a polymer having an aromatic ring in the side chain, and (C) A method for producing a polyamide resin composition, characterized by melt-kneading a compatibilizer. A method for producing a polyamide resin composition, wherein the polyamide resin composition is the polyamide resin composition according to any one of claims 1 to 11.

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