Polyamide resin composition

Abstract

Provided is a polyamide resin composition which exhibits good mechanical characteristics typified by tensile strength, good characteristics required of a sliding article, such as fatigue strength and abrasion resistance, and good molding properties typified by fluidity.　This polyamide resin composition contains an aliphatic polyamide resin (A) and glass fibers coated with a sizing agent. With regard to all polyamide resins in the polyamide resin composition, the ratio of the peak area of a polyamide resin having a molecular weight of 30,000 or less is 22.00-30.00 area% and the ratio of the peak area of a polyamide resin having a molecular weight of 100,000 or more is 14.00-27.00 area%, each relative to the total area of peaks calculated in terms of standard poly(methyl methacrylate) using gel permeation chromatography. The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is 4.00-8.50. The sizing agent contains a polyurethane resin and a copolymer having an acidic group.

Description

Polyamide resin composition

[0001] The present invention relates to a polyamide resin composition.

[0002] Polyamide resins have excellent properties as engineering plastics and are widely used in various industrial fields such as automobiles, machinery, electricity and electronics, etc. In particular, due to their excellent rigidity and toughness, polyamide resins are used in sliding parts used under frictional conditions, such as gears, cams, pulleys, bearings, bearing retainers, door checkers, and timing chain guide parts.

[0003] Wear resistance is required for applications in sliding parts, and to achieve this, various techniques have been employed, such as selecting a polyamide resin, incorporating a reinforcing material, and incorporating a thermoplastic resin other than polyamide resin. Patent Documents 1 to 3 disclose polyamide resin compositions in which two types of polyamide resins with different relative viscosities are blended with glass fibers. Patent Documents 3 and 4 disclose polyamide resin compositions in which glass fibers coated with a sizing agent are blended with a polyamide resin.

[0004] Japanese Patent Publication No. 2018-197316 Japanese Patent Publication No. 5973115 Japanese Patent Publication No. 2016-117817 Japanese Patent Publication No. 4321590

[0005] However, increasing the relative viscosity to enhance strength has the problem of reduced fluidity. Furthermore, the type of glass fiber sizing agent also affects the physical properties of the polyamide resin composition. Therefore, an object of the present invention is to provide a polyamide resin composition that has good mechanical properties, as measured by tensile strength, and excellent properties required for sliding parts, such as fatigue strength and abrasion resistance, as well as good moldability, as measured by fluidity.

[0006] The present invention relates to, for example, the following [1] to

[18] . [1] A polyamide resin composition comprising an aliphatic polyamide resin (A) and glass fibers (B) coated with a sizing agent, wherein, for all polyamide resins in the polyamide resin composition, the ratio of the peak area of ​​polyamide resins having a molecular weight of 30,000 or less is 22.00 to 30.00 area % and the ratio of the peak area of ​​polyamide resins having a molecular weight of 100,000 or more is 14.00 to 27.00 area % relative to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate, the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is 4.00 to 8.50, and the sizing agent comprises a polyurethane resin and a copolymer having an acidic group. [2] The polyamide resin composition of [1], wherein the relative viscosity of 1 g of the aliphatic polyamide resin (A) dissolved in 100 mL of 96% concentrated sulfuric acid, measured at 25°C in accordance with JIS K6920-2, is 2.50 to 3.35, and the aliphatic polyamide resin (A) has a terminal amino group concentration of more than 15.00 μmol / g and less than 50.00 μmol / g. [3] The polyamide resin composition of [1] or [2], comprising, per 100 mass% of the polyamide resin composition, 68 to 88 mass% of the aliphatic polyamide resin (A) and 5 to 30 mass% of the glass fiber (B) coated with the sizing agent. [4] The polyamide resin composition of any of [1] to [3], wherein the aliphatic polyamide resin (A) is an aliphatic homopolyamide resin (A-1). [5] The polyamide resin composition of [4], wherein the aliphatic polyamide resin (A) is a combination of two or more aliphatic homopolyamide resins (A-1) having different terminal amino group concentrations. [6] The polyamide resin composition of [4] or [5], wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-1) having structural units derived from an aminocarboxylic acid or a lactam. [7] The polyamide resin composition of [4] or [5], wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-2) having structural units derived from a reaction product of an aliphatic diamine and an aliphatic dicarboxylic acid.[8] The polyamide resin composition of [6], wherein the aliphatic homopolyamide resin (A-1-1) is at least one selected from the group consisting of polyamide 6, polyamide 11, and polyamide 12. [9] The polyamide resin composition of [7], wherein the aliphatic homopolyamide resin (A-1-2) is at least one selected from the group consisting of polyamide 56, polyamide 66, polyamide 410, polyamide 510, polyamide 610, and polyamide 612.

[10] The polyamide resin composition of any of [1] to [9], wherein the glass fiber (B) has an average fiber diameter of 5.0 to 12.0 μm.

[11] The polyamide resin composition of any of [1] to

[10] , wherein the glass fiber (B) has a number-average fiber length of 200 to 350 μm.

[12] The polyamide resin composition of any of [1] to

[11] , wherein the glass fiber (B) has a weight-average fiber length of 250 to 450 μm.

[13] The polyamide resin composition of any one of [1] to

[12] , wherein the content of the copolymer having an acidic group is 0.5 to 10.0 mass% based on 100 mass% of the sizing agent.

[14] The polyamide resin composition of any one of [1] to

[13] , wherein, based on 100 mass% of all structural units of the copolymer having an acidic group contained in the sizing agent, structural units derived from monomers having an acidic group account for 20 to 60 mass%.

[15] The polyamide resin composition of any one of [1] to

[14] , wherein the structural units derived from monomers having an acidic group in the copolymer having an acidic group contained in the sizing agent are structural units derived from unsaturated carboxylic acid and / or carboxylic acid anhydride.

[16] A molded product of any one of the polyamide resin compositions of [1] to

[15] .

[17] The molded product of

[16] , which is used for parts requiring sliding properties.

[0007] Further, examples of the second aspect of the invention include the following

[18] to

[29] .

[18] A polyamide resin composition comprising an aliphatic polyamide resin (A) and glass fibers (B) coated with a sizing agent, wherein 1 g of the aliphatic polyamide resin (A) is dissolved in 100 mL of 96% concentrated sulfuric acid and the relative viscosity measured at 25°C in accordance with JIS K6920-2 is 2.50 to 3.35, and the aliphatic polyamide resin (A) has a terminal amino group concentration of more than 15.00 μmol / g and less than 50.00 μmol / g, and the sizing agent comprises a polyurethane resin and a copolymer having an acidic group.

[19] The polyamide resin composition of

[18] , wherein the aliphatic polyamide resin (A) is an aliphatic homopolyamide resin (A-1).

[20] The polyamide resin composition of

[19] , wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-1) having structural units derived from an aminocarboxylic acid or a lactam.

[21] The polyamide resin composition of

[19] , wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-2) having structural units derived from a reaction product of an aliphatic diamine and an aliphatic dicarboxylic acid.

[22] The polyamide resin composition of

[20] , wherein the aliphatic homopolyamide resin (A-1-1) is at least one selected from the group consisting of polyamide 6, polyamide 11, and polyamide 12.

[23] The polyamide resin composition of

[21] , wherein the aliphatic homopolyamide resin (A-1-2) is at least one selected from the group consisting of polyamide 56, polyamide 66, polyamide 410, polyamide 510, polyamide 610, and polyamide 612.

[24] The polyamide resin composition of any of

[18] to

[23] , wherein the glass fibers (B) have an average fiber diameter of 5.0 to 12.0 μm when blended.

[25] The polyamide resin composition of any of

[18] to

[24] , wherein the content of the copolymer having an acidic group is 0.5 to 10.0 mass% based on 100 mass% of the sizing agent.

[26] The polyamide resin composition of any of

[18] to

[25] , wherein the content of structural units derived from a monomer having an acidic group is 20 to 60 mass% based on 100 mass% of all structural units of the copolymer having an acidic group contained in the sizing agent.

[27] The polyamide resin composition according to any one of

[18] to

[26] , wherein the structural unit derived from a monomer having an acidic group in the copolymer having an acidic group contained in the sizing agent is a structural unit derived from an unsaturated carboxylic acid and / or a carboxylic acid anhydride.

[28] A molded article of the polyamide resin composition according to any one of

[18] to

[27] .

[29] The molded article according to

[28] , which is used in an application requiring sliding properties.

[0008] The polyamide resin composition of the present invention has good mechanical properties represented by tensile strength, good fatigue strength and abrasion resistance, which are properties required for sliding articles, and good moldability represented by flowability.

[0009] A first aspect of the present invention is as follows: The present invention relates to a polyamide resin composition comprising an aliphatic polyamide resin (A) and glass fibers (B) coated with a sizing agent, wherein, for all polyamide resins in the polyamide resin composition, the ratio of the peak area of ​​polyamide resins having a molecular weight of 30,000 or less to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is 22.00 to 30.00 area %, and the ratio of the peak area of ​​polyamide resins having a molecular weight of 100,000 or more is 14.00 to 27.00 area %, the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is 4.00 to 8.50, and the sizing agent comprises a polyurethane resin and a copolymer having an acidic group.

[0010] <Aliphatic Polyamide Resin (A)> The polyamide resin composition contains an aliphatic polyamide resin (A). The aliphatic polyamide resin (A) is at least one polyamide resin selected from the group consisting of aliphatic homopolyamide resins (A-1) and aliphatic copolyamide resins (A-2).

[0011] (A-1) Aliphatic Homopolyamide Resin Aliphatic homopolyamide resin (A-1) refers to a polyamide resin in which the monomer component constituting the aliphatic polyamide resin is one type. Examples of the monomer component constituting the aliphatic polyamide resin include aminocarboxylic acids, lactams, or a combination of an aliphatic diamine and an aliphatic dicarboxylic acid. The combination of an aliphatic diamine and an aliphatic dicarboxylic acid refers to a monomer component consisting of a condensate of an aliphatic diamine and an aliphatic dicarboxylic acid. Furthermore, when the monomer components constituting the aliphatic polyamide resin are a combination of an aliphatic diamine and an aliphatic dicarboxylic acid, the combination of one type of aliphatic diamine and one type of aliphatic dicarboxylic acid is considered to be one type of monomer component. Aliphatic also includes alicyclic monomers. The aliphatic homopolyamide resin (A) is at least one aliphatic homopolyamide resin selected from the group consisting of aliphatic polyamide resins (A-1-1) having structural units derived from aminocarboxylic acids or lactams, and aliphatic polyamide resins (A-1-2) having structural units derived from a reaction product of an aliphatic diamine and an aliphatic dicarboxylic acid.

[0012] The aminocarboxylic acid preferably has 4 to 12 carbon atoms. The lactam preferably has 4 to 12 carbon atoms. The aliphatic diamine preferably has 2 to 20 carbon atoms, more preferably 4 to 12 carbon atoms. The aliphatic dicarboxylic acid preferably has 2 to 20 carbon atoms, more preferably 6 to 12 carbon atoms.

[0013] Examples of the aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Among these, from the viewpoint of polymerization production, one selected from the group consisting of 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid is preferred.

[0014] Examples of lactams include 2-pyrrolidone, 2-piperidone, ε-caprolactam, enantholactam, undecane lactam, lauryllactam, etc. Among these, from the viewpoint of polymerization production, one selected from the group consisting of ε-caprolactam, undecane lactam, and lauryllactam is preferred.

[0015] Examples of aliphatic diamines include non-alicyclic aliphatic diamines such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,8-octanediamine, and 2,2,4 / 2,4,4-trimethylhexamethylenediamine. Diamines include alicyclic diamines such as 1,3- / 1,4-cyclohexyldiamine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(3-methyl-4-aminocyclohexyl)methane, (3-methyl-4-aminocyclohexyl)propane, 1,3- / 1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, bis(aminopropyl)piperazine, bis(aminoethyl)piperazine, and norbornanedimethyleneamine. The aliphatic diamine may be a salt. Among these, from the viewpoint of polymerization productivity, aliphatic diamines other than alicyclic ones are preferred, and tetramethylenediamine, pentamethylenediamine, and hexamethylenediamine are more preferred.

[0016] Examples of aliphatic dicarboxylic acids include non-alicyclic aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedionic acid, dodecanedionic acid, tridecanedionic acid, tetradecanedionic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosanedioic acid; and alicyclic dicarboxylic acids such as 1,3- / 1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, and norbornanedicarboxylic acid. The aliphatic dicarboxylic acids may be salts. Among these, non-alicyclic aliphatic dicarboxylic acids are preferred, with one selected from the group consisting of adipic acid, sebacic acid, and dodecanedionic acid being more preferred, and adipic acid or dodecanedionic acid being even more preferred.

[0017] Examples of combinations of aliphatic diamines and aliphatic dicarboxylic acids include a combination of pentamethylenediamine and adipic acid, a combination of hexamethylenediamine and adipic acid, a combination of tetramethylenediamine and sebacic acid, a combination of pentamethylenediamine and sebacic acid, a combination of hexamethylenediamine and sebacic acid, and a combination of hexamethylenediamine and dodecanedioic acid, and equimolar salts of these combinations are preferably used.

[0018] Specific examples of the aliphatic homopolyamide resin (A-1) include polybutyrolactam (polyamide 4), polytetramethylene adipamide (polyamide 46), polytetramethylene azelamide (polyamide 49), polytetramethylene sebacamide (polyamide 410), and polyvalerolactam. (Polyamide 5), Polycaprolactam (Polyamide 6), Polyenantholactam (Polyamide 7), Polyundecanelactam (Polyamide 11), Polylauryllactam (Polyamide 12), Polypentamethylene adipamide (Polyamide 56), Polyhexamethylene adipamide (Polyamide 66), Polytetramethylene dodecamide (Polyamide 412), Polypentamethylene azelamide (Polyamide 59), Polypentamethylene sebacamide (Polyamide 510), Polypentamethylene dodecamide (Polyamide 512), Polypentamethylene tridecamide (Polyamide 513), Polyhexamethylene azelamide (Polyamide 69), Polyhexamethylene sebacamide (Polyamide 610), Polyhexamethylene dodecamide (Polyamide 612), polynonamethylene adipamide (polyamide 96), polynonamethylene azelamide (polyamide 99), polynonamethylene sebacamide (polyamide 910), polynonamethylene dodecamide (polyamide 912), polydecamethylene adipamide (polyamide 106), polydecamethylene azelamide (polyamide 109), polydecamethylene decamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene azelamide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), polydodecamethylene dodecamide (polyamide 1212), polydodecamethylene oxamide (polyamide 122), and the like. The aliphatic homopolyamide resin (A-1) may be used alone or in combination of two or more.

[0019] Among these, the aliphatic homopolyamide resin (A-1) is preferably an aliphatic homopolyamide resin (A-1-1) from the viewpoint of abrasion resistance, and is preferably an aliphatic homopolyamide resin (A-1-2) from the viewpoint of mechanical properties, and from the viewpoint of productivity, the aliphatic homopolyamide resin (A-1-1) is more preferably at least one selected from the group consisting of polyamide 6, polyamide 11, and polyamide 12. The aliphatic homopolyamide resin (A-1-2) is more preferably at least one selected from the group consisting of polyamide 56, polyamide 66, polyamide 410, polyamide 510, polyamide 610, and polyamide 612.

[0020] (A-2) Aliphatic Copolymer Polyamide Resin Aliphatic copolymer polyamide resin (A-2) is an aliphatic polyamide resin that contains two or more types of monomer components constituting the aliphatic polyamide resin and does not have an aromatic ring. Therefore, examples of aliphatic copolymer polyamide resin (A-2) include a combination of an aliphatic diamine and an aliphatic dicarboxylic acid, and an aliphatic copolymer polyamide resin that is a copolymer of two or more monomers selected from the group consisting of lactams and aminocarboxylic acids. The combination of an aliphatic diamine and an aliphatic dicarboxylic acid refers to a monomer component formed from a condensation product of an aliphatic diamine and an aliphatic dicarboxylic acid. In this context, the combination of an aliphatic diamine and an aliphatic dicarboxylic acid is considered to be one type of monomer, with one type of diamine and one type of dicarboxylic acid being the combination. Aliphatic also includes alicyclic monomers.

[0021] Examples of the aliphatic diamine include those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). The aliphatic diamine may be used alone or in combination of two or more. Among these, from the viewpoint of polymerization productivity, at least one selected from the group consisting of aliphatic diamines other than alicyclic is preferred, at least one selected from the group consisting of linear aliphatic diamines is more preferred, and hexamethylenediamine is even more preferred.

[0022] Examples of the aliphatic dicarboxylic acid include the same as those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). The aliphatic dicarboxylic acid may be used alone or in appropriate combination of two or more. Among these, aliphatic dicarboxylic acids other than alicyclic are preferred, more preferably at least one selected from the group consisting of adipic acid, sebacic acid, and dodecanedioic acid, and even more preferably at least one selected from the group consisting of adipic acid and dodecanedioic acid.

[0023] Examples of lactams include those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). One lactam may be used alone, or two or more lactams may be used in appropriate combination. Among these, from the viewpoint of polymerization productivity, at least one lactam selected from the group consisting of ε-caprolactam, undecane lactam, and lauryllactam is preferred.

[0024] Examples of aminocarboxylic acids include those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). One aminocarboxylic acid may be used alone, or two or more aminocarboxylic acids may be used in appropriate combination. Among these, from the viewpoint of polymerization production, at least one selected from the group consisting of 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid is preferred.

[0025] Specific examples of the aliphatic copolymer polyamide resin (A-2) include caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 66), caprolactam / hexamethylenediaminoazelaic acid copolymer (polyamide 6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (polyamide 6 / 610), caprolactam / hexamethylenediaminoundecanoic acid copolymer (polyamide 6 / 611), caprolactam / hexamethylenediaminododecanoic acid copolymer (polyamide 6 / 612), caprolactam / aminoundecanoic acid copolymer (polyamide 6 / 11), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 613), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 614), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 615), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 616), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 617), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 618), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 619), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 620), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 621), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 622), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 623), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 624), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 625), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 Examples of the aliphatic copolyamide resin (A-2) include aliphatic copolyamides such as caprolactam / lauryllactam copolymer (polyamide 6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (polyamide 6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (polyamide 6 / 66 / 610), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (polyamide 6 / 66 / 612), and hexamethylenediaminoadipic acid / caprolactam copolymer (polyamide 66 / 6). The aliphatic copolyamide resin (A-2) may be used alone or as a mixture of two or more.

[0026] Among these, from the viewpoint of suppressing the water absorption rate of the molded product and maintaining the mechanical strength, at least one selected from the group consisting of polyamide 6 / 66, polyamide 6 / 12 and polyamide 6 / 66 / 12 is preferred, at least one selected from the group consisting of polyamide 6 / 66 and polyamide 6 / 66 / 12 is more preferred, and polyamide 6 / 66 is particularly preferred.

[0027] From the viewpoint of productivity, the aliphatic polyamide resin (A) preferably has a structural unit derived from an aminocarboxylic acid or a lactam, or a structural unit derived from a reaction product of a diamine and a dicarboxylic acid, and is more preferably an aliphatic homopolyamide resin (A-1), and is preferably at least one selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 56, polyamide 66, polyamide 410, polyamide 510, polyamide 610, and polyamide 612, and is more preferably polyamide 6 or polyamide 66.

[0028] The aliphatic polyamide resin (A) can be produced by polymerizing the polyamide resin (A) by repeating normal pressure, reduced pressure, and increased pressure operations using a known method such as melt polymerization, solution polymerization, or solid-state polymerization in a known polyamide production apparatus such as a batch reaction vessel, a single- or multi-vessel continuous reactor, a tubular continuous reactor, a kneading reaction extruder such as a single-screw kneading extruder, or a twin-screw kneading extruder. These polymerization methods can be used alone or in appropriate combination.

[0029] The relative viscosity of the aliphatic polyamide resin (A) is preferably 2.50 to 3.35, more preferably 2.55 to 3.35, and even more preferably 2.60 to 3.30. If it is lower than the above range, abrasion resistance decreases and molding unevenness occurs during molding. If it is higher than the above range, fluidity decreases and moldability is poor. When it is within the above range, fluidity, moldability, and abrasion resistance are good. The relative viscosity is a value measured in accordance with JIS K6920-2 by dissolving 1 g of polyamide in 100 ml of 96% concentrated sulfuric acid at 25°C.

[0030] The relative viscosity of aliphatic polyamide resin (A) refers to the relative viscosity of the mixture when the aliphatic polyamide resin (A) is a mixture containing two or more aliphatic polyamide resins.Therefore, when the aliphatic polyamide resin (A) contains two or more polyamide resins with different relative viscosities, the relative viscosity of the aliphatic homopolyamide resin (A) is preferably measured as described above.However, if the relative viscosity of each polyamide resin and its mixing ratio are known, the average value calculated by multiplying each relative viscosity by its mixing ratio can also be used as the relative viscosity of the aliphatic polyamide resin (A).In the present invention, the measured value is used.

[0031] The terminal amino group concentration of the aliphatic polyamide resin (A), as determined by dissolving the resin in a mixed solvent of phenol and methanol and performing neutralization titration, is preferably greater than 15.00 μmol / g and less than 50.00 μmol / g, more preferably 20.00 to 45.00 μmol / g, and even more preferably 25.00 to 40.00 μmol / g. If the concentration is lower than this range, the fluidity decreases, and if the concentration is higher than this range, the molded product becomes too hard and the abrasion resistance decreases. If the concentration is within this range, sufficient moldability, abrasion resistance, and mechanical properties can be obtained.

[0032] The terminal amino group concentration of the aliphatic polyamide resin (A) refers to the terminal amino group concentration of the mixture when the aliphatic polyamide resin (A) is a mixture containing two or more aliphatic polyamide resins. Therefore, when the aliphatic polyamide resin (A) contains two or more polyamide resins with different terminal amino group concentrations (for example, at least one aliphatic homopolyamide resin (A-1) and at least one aliphatic copolymer polyamide resin (A-2)), the terminal amino group concentration of the polyamide resin (A) is preferably measured by the neutralization titration method described above. However, if the terminal amino group concentrations of each polyamide resin and their mixing ratios are known, the terminal amino group concentration of the polyamide resin (A) can also be calculated by multiplying each terminal amino group concentration by the mixing ratio and adding up the average value. In the present invention, the calculated value is used.

[0033] The aliphatic polyamide resin (A) may be a single component or a combination of two or more aliphatic polyamide resins, but from the viewpoint of sliding properties, it is preferable to have a combination of two or more aliphatic homopolyamide resins (A-1) with different terminal amino group concentrations, a combination of two or more aliphatic homopolyamide resins (A-1-1) with different terminal amino group concentrations, a combination of two or more aliphatic homopolyamide resins (A-1-2) with different terminal amino group concentrations, and a combination of one or more aliphatic homopolyamide resins (A-1-1) and one or more aliphatic homopolyamide resins (A-1-2) are more preferred. These combinations are preferably combinations in which either one of the aliphatic homopolyamide resins satisfies the preferred range of the terminal amino group concentration of the entire aliphatic polyamide resin (A). Further, among these combinations, a combination of an aliphatic homopolyamide resin (A-1-2) having a terminal amino group concentration lower than that of the entire aliphatic polyamide resin (A) and an aliphatic homopolyamide resin (A-1-2) having a terminal amino group concentration higher than that of the entire aliphatic polyamide resin (A) is more preferred, and it is particularly preferred that the content of the former is greater than the content of the latter.

[0034] The amount of the aliphatic polyamide resin (A) is preferably 68 to 88% by mass, more preferably 70 to 85% by mass, and even more preferably 70 to 80% by mass, based on 100% by mass of the polyamide resin composition. When the amount of the polyamide resin (A) is within the above range, the mechanical properties and moldability are good.

[0035] <Molecular Weight of Polyamide Resin> The polyamide resin contained in the polyamide resin composition has the following molecular weight characteristics: For all polyamide resins in the polyamide resin composition, the ratio of the peak area of ​​polyamide resins having a molecular weight of 30,000 or less to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is 22.00 to 30.00 area%, preferably 22.20% to 30.00 area%, and more preferably 22.50 to 30.00 area%, and the ratio of the peak area of ​​polyamide resins having a molecular weight of 100,000 or more to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is 14.00 to 27.00 area%, preferably 14.00 to 25.00 area%, and more preferably 14.00 to 23.00 area%.

[0036] By setting the proportion of polyamide resins having a molecular weight of 30,000 or less and the proportion of polyamide resins having a molecular weight of 100,000 or more, calculated using gel permeation chromatography in terms of standard polymethyl methacrylate, within the above ranges, it is possible to improve the abrasion resistance of molded articles of the polyamide resin composition.

[0037] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is 4.00 to 8.50, preferably 4.15 to 7.50, and more preferably 4.30 to 6.50. By setting the molecular weight distribution (Mw / Mn) within the above range, the flowability of the polyamide resin composition can be improved.

[0038] By setting the proportion of polyamide resins having a molecular weight of 30,000 or less and the proportion of polyamide resins having a molecular weight of 100,000 or more within the above ranges and by setting the molecular weight distribution (Mw / Mn) within the above ranges, it is possible to maintain mechanical strength suitable for sliding applications.

[0039] In order to ensure that the proportion of polyamide resins having a molecular weight of 30,000 or less and the proportion of polyamide resins having a molecular weight of 100,000 or more fall within the above ranges and that the molecular weight distribution (Mw / Mn) falls within the above ranges, it is sufficient to appropriately select production conditions and production forms that will result in the ranges. For example, this can be achieved by mixing multiple lots of polyamide resins produced in a batch system, or by producing in a continuous system while adjusting and changing the production conditions (temperature, pressure, etc.).

[0040] The molecular weight, number average molecular weight (Mn) and weight average molecular weight (Mw) can be measured by gel permeation chromatography (GPC). The detailed conditions for gel permeation chromatography are as described in the Examples.

[0041] <Glass fiber (B) coated with a sizing agent containing a polyurethane resin and a copolymer having an acidic group> The polyamide resin composition contains glass fiber (B) coated with a sizing agent. The sizing agent contains a polyurethane resin and a copolymer having an acidic group. The glass fiber (B) coated with a sizing agent containing a polyurethane resin and a copolymer having an acidic group is a component that imparts excellent sliding properties and mechanical properties to the polyamide resin composition.

[0042] [Glass Fiber] Examples of glass constituting the glass fiber include those having compositions such as A glass, AR glass, C glass, D glass, E glass, H glass, S glass, T glass, M glass, and NE glass.

[0043] The shape of the glass fiber is not particularly limited, and examples thereof include flat fiber and chopped strand. The cross-sectional shape of the glass fiber is not particularly limited, and examples thereof include circular, cocoon-shaped, oval, rectangular, and shapes similar thereto. The term "fiber" refers to a shape having an aspect ratio (ratio of major axis / minor axis) of 10 or more. The glass fiber (B) breaks when melt-kneaded with other components. Therefore, the glass fiber (B) in the polyamide resin composition includes glass fibers that are broken during melt-kneading and therefore no longer meet the definition of "fiber" in this specification, as long as they meet the definition of "fiber" in this specification when blended.

[0044] The average fiber diameter of the glass fibers at the time of blending and in the polyamide resin composition is preferably 5.0 μm to 12.0 μm. When the average fiber diameter of the glass fibers is within the above range, the sliding properties are excellent and the amount of wear is suppressed. The average fiber diameter of the glass fibers is a value measured using an optical microscope, and when a commercially available product is used, it may be a catalog value. The average fiber diameter of the glass fibers (B) coated with a sizing agent is also preferably within the same range as above.

[0045] When the cross section of the glass fiber is rectangular or similar, the length of one side of the cross section is preferably 0.5 μm to 50 μm, more preferably 1 to 40 μm. The number-average fiber length of the glass fiber at the time of blending is preferably 2000 μm to 4000 μm, more preferably 2500 μm to 3500 μm. Because polyamide resin compositions are produced by melt-kneading, dimensional changes occur due to breakage of the glass fibers during the blending process. Therefore, the number-average fiber length of the glass fiber in the polyamide resin composition is preferably 100 μm to 450 μm, more preferably 200 μm to 350 μm. The weight-average fiber length of the glass fiber in the polyamide resin composition is preferably 150 μm to 550 μm, more preferably 250 μm to 450 μm. The number-average fiber length and weight-average fiber length of the glass fiber can be determined using image analysis software from images taken with a transmission microscope. The aspect ratio of the glass fibers in the polyamide resin composition, obtained by dividing the number-average fiber length by the average fiber diameter, is preferably 10 or more, more preferably 15 to 100, and particularly preferably 30 to 70, from the viewpoints of rigidity, mechanical strength, and flowability. The number-average fiber length and weight-average fiber length of the glass fibers (B) coated with a sizing agent are also preferably in the same ranges as above. Note that "glass fibers in the polyamide resin composition" refers to glass fibers in a polyamide resin composition obtained by melt-kneading each component.

[0046] [Sizing Agent] The glass fiber is coated with a sizing agent containing a polyurethane resin and a copolymer having an acidic group. The sizing agent is a composition applied to the surface of the glass fiber for the purpose of organifying the glass fiber surface. It contains a resin and optionally also contains a coupling agent, water, an organic solvent, etc., as described below. It is not necessarily used to bundle multiple glass fibers, but may be applied to the surface of a single glass fiber. The glass fiber is surface-treated by being coated with the sizing agent. "Coated" means that the sizing agent is attached to at least a portion of the surface of at least one glass fiber. The glass fiber may also be subjected to a bundling process using the sizing agent to bundle two or more glass fibers into one. The bundling process can also be performed by applying the sizing agent to multiple glass fiber monofilaments formed by drawing molten glass from multiple nozzles, bundling them into a single glass fiber strand, and then winding it up as a cake.

[0047] [Polyurethane Resin] The polyurethane resin is a resin obtained by a urethane reaction between a polyol component and a polyisocyanate component.

[0048] <Polyol Component> Examples of the polyol component include polyester polyols (condensation polyester polyols, lactone polyester polyols), polycarbonate polyols, and polyether polyols.

[0049] Condensation polyester polyols include those obtained by reacting dicarboxylic acids or lower alkyl esters thereof with aliphatic diols. Examples of dicarboxylic acids or lower alkyl esters thereof include adipic acid, succinic acid, azelaic acid, pimelic acid, sebacic acid, phthalic acid, etc., or lower alkyl esters thereof. Examples of aliphatic diols include aliphatic diols without side chains, such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and 1,10-decamethylene glycol, and aliphatic diols with side chains, such as 1,2-propylene glycol, 1,3-butanediol, 2,5-dimethyl-2,5-hexanediol, 2,2-diethyl-1,3-propanediol, and neopentyl glycol.

[0050] Examples of lactone-based polyester polyols include those obtained by reacting a lactone compound such as β-propiolactone, pivalolactone, δ-valerolactone, ε-caprolactone, methyl-ε-caprolactone, dimethyl-ε-caprolactone, or trimethyl-ε-caprolactone with a hydroxy compound such as a short-chain polyol.

[0051] Polycarbonate polyols that can be used are those obtained by transesterification of a hydroxy compound such as a short-chain polyol with diallyl carbonate, dialkyl carbonate, or ethylene carbonate. For example, poly-1,6-hexamethylene carbonate, poly-2,2'-bis(4-hydroxyhexyl)propane carbonate, etc. are industrially produced and easily available. Another method for obtaining polycarbonate polyols is the so-called phosgene method (or solvent method).

[0052] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxypropylene glycol, and glycerin-based polyalkylene ether glycol.

[0053] <Polyisocyanate Component> Examples of the polyisocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates.

[0054] Examples of aliphatic polyisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0055] Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate.

[0056] Examples of aromatic polyisocyanates include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenyl, Phenylmethane, 1,5-naphthylene diisocyanate, 4,4',4''-triphenylmethane triisocyanate, m-isocyanatophenylsulfonyl isocyanate, p-isocyanatophenylsulfonyl isocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate , 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate, 2,2'-diphenylmethane diisocyanate, and the like.

[0057] The polyisocyanate is preferably a diisocyanate having two isocyanato groups per molecule.

[0058] In the urethane reaction, a chain extender such as a polyhydric alcohol or a polyhydric amine may also be used.

[0059] [Copolymer Having Acidic Group] The copolymer having an acidic group may be a copolymer of a monomer having an acidic group, or a copolymer of a monomer having an acidic group and a monomer not having an acidic group. In this specification, the acidic group refers to a group that liberates a proton, and examples thereof include a carboxyl group, a sulfonic acid group, a phosphoric acid group, and a phenolic hydroxyl group, but does not include a hydroxyl group (excluding a phenolic hydroxyl group).

[0060] Examples of monomers having an acidic group include unsaturated carboxylic acids and carboxylic acid anhydrides. Examples of unsaturated carboxylic acids include acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, mesaconic acid, citraconic acid, crotonic acid, isocrotonic acid, and endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid. Examples of carboxylic acid anhydrides include dicarboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, succinic anhydride, phthalic anhydride, glutaric anhydride, dodecenylsuccinic anhydride, chlorendic acid anhydride, and citraconic anhydride. The carboxylic acid anhydride is preferably maleic anhydride because it causes little steric hindrance during copolymerization and has low polarity. The monomer having an acidic group may also be a monomer having a functional group having the same function as the acidic group, and examples of such functional groups include acid halides, amides, imides, and esters of the unsaturated carboxylic acids, and examples of monomers having a functional group having the same function as the acidic group include malenyl chloride, maleimide, monomethyl maleate, dimethyl maleate, glycidyl maleate, etc. These may be used alone or in combination of two or more.

[0061] Examples of monomers that do not have an acidic group include styrene, ethylene, and acetylene.

[0062] The structural unit derived from a monomer having an acidic group in the copolymer having an acidic group contained in the bundling agent is preferably a structural unit derived from an unsaturated carboxylic acid and / or a carboxylic acid anhydride.The copolymer having an acidic group more preferably includes a copolymer obtained by copolymerizing an unsaturated carboxylic acid and / or a carboxylic acid anhydride with methyl acrylate and methyl methacrylate.

[0063] From the viewpoints of reactivity during production of the copolymer and mechanical properties, the weight-average molecular weight of the copolymer is preferably 10,000 to 60,000, and particularly preferably 20,000 to 50,000. The weight-average molecular weight of the copolymer is a molecular weight measured by gel permeation chromatography (GPC).

[0064] [Other Optional Components of Sizing Agent] The sizing agent may contain further components in addition to the polyurethane resin and the copolymer having an acidic group. Examples of such further components include coupling agents, lubricants, nonionic surfactants, antistatic agents, water, organic solvents, etc. Examples of lubricants include fatty acid amides and quaternary ammonium salts. Examples of nonionic surfactants include synthetic alcohols, natural alcohols, and fatty acid esters. Water and organic solvents are components that dissolve the lubricants, nonionic surfactants, antistatic agents, etc. Examples of organic solvents include ethanol, etc.

[0065] The content of each component in the sizing agent can be appropriately set depending on the properties of the glass fibers to be obtained.

[0066] The glass fibers (B) coated with the sizing agent may be surface-treated with an additional component, such as the additional component contained in the sizing agent.

[0067] The sizing agent containing a polyurethane resin and a copolymer having an acidic group may contain, in addition to the components described above, the components described in JP 2014-231452 A. The glass fiber (B) coated with the sizing agent containing a polyurethane resin and a copolymer having an acidic group may be a single component or a combination of two or more components.

[0068] From the viewpoint of exhibiting strength improving performance, the ignition loss when the volatile substances are completely evaporated from the sizing agent is preferably 0.1 to 1.5 mass%, more preferably 0.4 to 1.2 mass%. The ignition loss of the sizing agent is a value measured in accordance with JIS R 3420 (2006) 7.3.2.

[0069] It is believed that the acidic groups of the copolymer having acidic groups in the sizing agent that coats the glass fiber interact with the terminal amino groups of the polyamide resin contained in the aliphatic polyamide resin (A). By improving this interaction, the fatigue strength can be improved, but if the interaction is too high, the polyamide resin composition becomes hard, and the wear amount may increase. In order to moderate the interaction, it is also preferable to adjust the terminal amino group concentration of the aliphatic polyamide resin (A). Furthermore, it is also preferable to adjust the amount of acidic groups in the sizing agent that coats the glass fiber.

[0070] From the viewpoint of making the above-mentioned interaction moderate and improving the dispersibility of the glass fibers in the polyamide resin, the content of the copolymer having an acidic group in 100% by mass of the sizing agent is preferably 0.5 to 10.0% by mass, and more preferably 1.0 to 8.0% by mass. Also, from the viewpoint of making the above-mentioned interaction moderate, the content of the structural units derived from the monomer having an acidic group in 100% by mass of all structural units of the copolymer having an acidic group contained in the sizing agent is preferably 10 to 99% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 55% by mass.

[0071] The content of the glass fiber (B) coated with a bundling agent in 100% by mass of the polyamide resin composition is preferably 5 to 30% by mass, more preferably 10 to 30% by mass, and even more preferably 15 to 30% by mass. The blending amount of the glass fiber (B) in the above range is preferable from the viewpoints of mechanical properties, sliding properties, and moldability.

[0072] <Optional Components> The polyamide resin composition may contain optional components other than the components (A) and (B) as long as the effects of the present invention are not impaired. Examples of the optional components include resins other than the component (A) and functionality-imparting agents.

[0073] Examples of resins other than component (A) include aromatic polyamide resins, semi-aromatic polyamide resins, polyolefin resins such as low-density, medium-density, and high-density polyethylene, polypropylene, and polybutene, modified polyolefin resins, polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyester-based elastomers, vinyl aromatic resins such as polystyrene, ABS resin, and AS resin, polyether resins, polyurethane resins, acrylic resins, polyimide resins, polycarbonate resins, polyacetal, polyvinyl alcohol, and rosin resins.

[0074] When resins other than component (A) are blended, the amount thereof is preferably 0.01 to 2.0 mass%, more preferably 0.05 to 1.5 mass%, and more preferably 0.1 to 1.0 mass%, based on 100 mass% of the polyamide resin composition, from the viewpoint of not impairing the functions and properties of the polyamide resin composition.

[0075] Examples of the functionality-imparting agent include various additives that are usually blended into polyamide resin compositions, such as plasticizers, heat resistance agents, foaming agents, weather resistance agents, crystal nucleating agents, antioxidants, crystallization accelerators, mold release agents, lubricants, antistatic agents, dispersants, flame retardants, flame retardant assistants, pigments, and dyes.

[0076] When the functionality-imparting agent is a heat-resistant agent, organic or inorganic heat-resistant agents can be used depending on the purpose, and these may be used alone or in combination of two or more. The heat-resistant agent refers to a component that suppresses thermal oxidation and thermal degradation of the polyamide resin, and for that purpose also includes what is called an antioxidant.

[0077] Examples of organic heat-resistant additives include phenolic compounds, phosphorus compounds, sulfur compounds, and nitrogen compounds. These may be used alone or in combination of two or more. Preferred examples of phenolic compounds include hindered phenolic compounds. In this specification, hindered phenol refers to a compound having a substituent at the ortho position of the phenolic hydroxyl group. Preferred examples of phosphorus compounds include hindered phenol phosphite compounds and hindered phenol hypophosphite compounds.

[0078] The heat-resistant agent is preferably a combination of an inorganic compound and an inorganic compound, or a combination of an inorganic compound and a nitrogen-containing compound. Examples of the inorganic compound include metal halides and inorganic compounds other than metal halides.

[0079] Metal halides are compounds of halogens and metals. Examples of halogens include fluorine, chlorine, bromine, and iodine. Examples of metals include Group 1 elements (alkali metals), Group 2 elements (alkaline earth metals), and Group 3 to Group 12 elements (e.g., transition metals). The metal in the metal halide is preferably a Group 1 element (alkali metal) or a Group 11 element (copper group), and combinations thereof are more preferred. Examples of metal halides when the metal is a Group 1 element (alkali metal) include potassium iodide, potassium bromide, potassium chloride, sodium iodide, and sodium chloride. Examples of metal halides when the metal is a Group 11 element (copper group) include cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, and cupric iodide. Potassium iodide and / or cuprous iodide are particularly preferred as the metal halide.

[0080] Examples of the nitrogen-containing compound include melamine, benguanamine, dimethylol urea, and cyanuric acid.

[0081] When a heat-resistant agent is blended, the blending amount of the heat-resistant agent is preferably 0.01 to 2.00 mass%, more preferably 0.05 to 1.00 mass%, more preferably 0.10 to 0.50 mass%, based on 100 mass% of the polyamide resin composition.

[0082] The release agent may be a higher fatty acid compound, and the higher fatty acid compound is preferably at least one selected from the group consisting of higher fatty acid esters, higher fatty acid amides, and higher fatty acid salts.

[0083] Examples of functionality-imparting agents other than those mentioned above include metals, metal oxides, metal hydroxides, metal nitrides, metal phosphates, metal phosphites, metal carbonates, metal silicates, metal titanates, metal borates, metal sulfates, metal nitrates, etc. Specific examples of inorganic compounds other than metal halides include talc, mica, synthetic mica, glass flakes, non-swelling mica, fullerene, carbon nanotubes, carbon black, graphite, metal foil, ceramic beads, clay, sericite, zeolite, bentonite, aluminum hydroxide, dolomite, kaolin, silica, finely powdered silicic acid, feldspar powder, potassium titanate, shirasu balloons, calcium carbonate, magnesium carbonate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide, magnesium oxide, and aluminum silicate. Examples of optional components include titanium, silicon oxide, magnesium hydroxide, gypsum, novaculite, dawsonite, clay, glass fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium-based whisker, silicon-based whisker, wollastonite, sepiolite, slag fiber, zonolite, elestadite, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, and boron fiber, as well as other components described in JP 2002-370551 A. Each optional component may be a single component or a combination of two or more components.

[0084] <Method for producing polyamide resin composition> The method for producing a polyamide resin composition is not particularly limited as long as it is a method that can knead the respective components, and examples thereof include production methods using a twin-screw extruder, a single-screw extruder, a multi-screw extruder, etc. For example, any of the following methods may be used: a method using a twin-screw extruder to blend all of the raw materials and then melt-knead them, a method using a twin-screw extruder to blend some of the raw materials and then melt-knead them, and then further blend and melt-knead the remaining raw materials, or a method using a side feeder to blend some of the raw materials and then mix the remaining raw materials during melt-kneading.

[0085] [Uses of Polyamide Resin Compositions, etc.] The polyamide resin composition can be used to produce molded articles using known methods such as injection molding, extrusion molding, blow molding, rotational molding, vacuum molding, and pressure molding, without any particular limitations. Furthermore, molded articles containing the polyamide resin composition can be used for parts requiring sliding properties. Examples of parts requiring sliding properties include gears, cams, pulleys, bearings, bearing retainers, door checks, timing chain guides, and cable / hose support / guiding device parts, which are intended for dynamic applications. The polyamide resin composition can also be used for other components requiring similar functions.

[0086] A second aspect of the present invention is as follows: A polyamide resin composition comprising an aliphatic polyamide resin (A) and glass fibers (B) coated with a sizing agent, wherein the relative viscosity measured at 25°C in accordance with JIS K6920-2 when 1 g of the aliphatic polyamide resin (A) is dissolved in 100 mL of 96% concentrated sulfuric acid is 2.50 to 3.35, and the aliphatic polyamide resin (A) has a terminal amino group concentration of more than 15.00 μmol / g and less than 50.00 μmol / g, and the sizing agent comprises a polyurethane resin and a copolymer having an acidic group.

[0087] The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is preferably 4.00 to 8.50, more preferably 4.15 to 7.50, and even more preferably 4.30 to 6.50.

[0088] For all polyamide resins in the polyamide resin composition, the ratio of the peak area of ​​polyamide resins having a molecular weight of 30,000 or less to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is preferably 22.00 to 30.00 area%, more preferably 22.20% to 30.00 area%, and even more preferably 22.50 to 30.00 area%, and the ratio of the peak area of ​​polyamide resins having a molecular weight of 100,000 or more to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is preferably 14.00 to 27.00 area%, more preferably 14.00 to 25.00 area%, and even more preferably 14.00 to 23.00 area%.

[0089] The preferred embodiments of the polyamide resin, sizing agent and glass fiber, as well as the method for measuring the above values, are the same as those in the first embodiment of the present invention.

[0090] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0091] <<Measurement Method and Evaluation>> ◯ was evaluated as pass, and × was evaluated as fail. (1) Molecular Weight Ratio, Number Average Molecular Weight (Mn), Weight Average Molecular Weight (Mw), and Molecular Weight Distribution (Mw / Mn) The molecular weight ratio, number average molecular weight (Mn), and weight average molecular weight (Mw) were calculated using standard polymethyl methacrylate (PMMA) equivalents by GPC (gel permeation chromatography) (Tosoh HLC-8420). The measurement sample concentration was 0.05 wt / vol%, the solvent was a mixture of hexafluoro-2-propanol and 10 mM sodium trifluoroacetate, the flow rate was 0.8 mL / min, two Shodex KF-805L (trade name) columns were connected in series, the injection volume was 100 μL, the column temperature was 40 °C, and a differential refractometer (RI) was used as the detector. The molecular weight ratio was determined by calculating the area ratio of the corresponding molecular weight relative to the total area of ​​the peaks obtained by the above measurement.

[0092] (2) Tensile strength Type A test pieces were prepared in accordance with ISO 294-1, and tensile tests were carried out in an atmosphere of 23°C in accordance with ISO 527-1, 2. ◯: Tensile strength is 174.0 MPa or more, excellent mechanical strength. ×: Tensile strength is less than 174.0 MPa, poor mechanical strength.

[0093] (3) Fluidity Using an injection molding machine (manufactured by Nissei Plastic Industrial Co., Ltd., product name: PS40E) equipped with a bar flow mold having a cavity thickness of 1 mm, width of 15 mm, and length of 360 mm, the pellets of the Examples and Comparative Examples were injection molded under the following molding conditions: injection pressure of 100 MPa, cylinder temperature of 290°C, mold temperature of 80°C, injection speed of 38 mm / sec, injection time of 4 seconds, and cooling time of 15 seconds. The total length from the gate exit of the molded article obtained by injection molding was measured as the L / T flow length. The fluidity of the polyamide resin composition was evaluated according to the following criteria: ∘: L / T flow length is 50.0 mm or more, excellent fluidity; ×: L / T flow length is less than 50.0 mm, poor fluidity.

[0094] (4) Fatigue Strength Using a bending fatigue testing machine (manufactured by Toyo Seiki Seisakusho, product name B-70-T-40+200), ASTM D 671 test pieces were prepared based on ASTM D671 Method B, and fatigue tests were performed in a 90°C atmosphere under vibration conditions of constant stress amplitude, sine wave, stress ratio -1, and frequency 30 Hz. The set stress when 10,000,000 cycles could be reached was taken as the fatigue strength. ◯: Fatigue strength is 35.0 MPa or more, excellent fatigue strength. ×: Fatigue strength is less than 35.0 MPa, poor fatigue strength.

[0095] (5) Wear Resistance To confirm the wear volume of the sliding parts, the wear volume of the polyamide resin composition against carbon steel was measured as follows. Using an SE100D-C160S injection molding machine manufactured by Sumitomo Heavy Industries, Ltd., 60 mm x 40 mm x 3 mm test pieces of the polyamide resin compositions of the Examples and Comparative Examples were prepared. A friction and wear tester (UMT-TribolaB manufactured by Bruker) was used. An SR10 pin, made of SUJ2 carbon steel as specified in JIS G4805, was used. A reciprocating test of the pin on the test piece was performed under conditions of a test load of 10 N, a frequency of 15 Hz, and a stroke of 10 mm. After 6 hours (324,000 cycles), the wear volume of the polyamide sliding surface of the test piece was measured. The wear volume was measured using a 3D shape measuring machine (VR3200 manufactured by Keyence). ◯: Polyamide wear volume was 1.90 mm ３ Less than 1.90 mm, excellent abrasion resistance. ３ As a result, the abrasion resistance is poor.

[0096] (6) Average fiber diameter, number average fiber length, and weight average fiber length The average fiber diameter of the glass fibers in the polyamide resin composition was measured using an optical microscope. The number average fiber length and weight average fiber length in the polyamide resin composition were calculated from 1,000 or more fibers using image analysis software from images taken using a transmission microscope.

[0097] The components used in the examples and comparative examples are as follows. PA66 (1): Polyamide 66, relative viscosity 2.40, terminal amino group concentration 59.0 μmol / g, manufactured by Asahi Kasei Corporation PA66 (2): Polyamide 66, relative viscosity 2.73, terminal amino group concentration 50.0 μmol / g, manufactured by Asahi Kasei Corporation PA66 (3): Polyamide 66, relative viscosity 3.73, terminal amino group concentration 15.0 μmol / g, manufactured by Asahi Kasei Corporation PA6 (1): Polyamide 6, relative viscosity 2.47, terminal amino group concentration 44.5 μmol / g, manufactured by UBE Corporation PA6 (2): Polyamide 6, relative viscosity 2.96, terminal amino group concentration 30.0 μmol / g, manufactured by UBE Corporation PA6 (3): Polyamide 6, relative viscosity 4.05, terminal amino group concentration 32.0 μmol / g, manufactured by UBE Corporation Glass fiber (1): Round chopped ECS03T-249H Glass fiber (2): Round chopped CS 3DE-456S Φ6.5 microns (manufactured by Nitto Boseki Co., Ltd.; average fiber diameter 6.5 μm; coated with a sizing agent containing polyurethane resin and not containing a copolymer having an acidic group) Glass fiber (3): Round chopped ECS03T-211H Φ10.5 microns (manufactured by Nippon Electric Glass Co., Ltd.; average fiber diameter 10.5 μm; coated with a sizing agent containing polyurethane resin and a copolymer having an acidic group) Glass fiber (4): Round chopped ECS03T-211DE Φ6.5 microns (manufactured by Nippon Electric Glass Co., Ltd.; average fiber diameter 6.5 μm; coated with a sizing agent containing polyurethane resin and a copolymer having an acidic group) Heat resistance agent: CuI / KI: cuprous iodide / potassium iodide = 1 / 6 (mixture, mass ratio) The relative viscosity of polyamide 66 and polyamide 6 was measured in accordance with JIS K6920-2 by dissolving 1 g of polyamide in 100 ml of 96% concentrated sulfuric acid at 25°C. The terminal amino group concentrations of polyamide 66 and polyamide 6 were determined by dissolving the polyamide resin in a mixed solvent of phenol and methanol and performing neutralization titration. When two or more polyamide resins were used as a mixture, the relative viscosity of the entire polyamide resin was determined in accordance with JIS K6920-2 by dissolving 1 g of polyamide in 100 ml of 96% concentrated sulfuric acid at 25°C.When the polyamide resin is a mixture of two or more types, the terminal amino group concentration of the entire polyamide resin is determined by multiplying the terminal amino group concentration of each polyamide resin measured by the above method by the mixing ratio thereof, and then calculating the average value. The average fiber diameter of the glass fiber is a catalog value.

[0098] [Examples 1 to 5, Comparative Examples 1 to 5 and 7, Reference Example 6] The components listed in Table 1 were melt-kneaded in a Coperion ZSK32Mc twin-screw kneader to produce the desired polyamide resin composition pellets. Unless otherwise specified in the evaluation method, the resulting pellets were injection-molded at a cylinder temperature of 290°C and a mold temperature of 80°C to produce various test pieces, and various physical properties were evaluated. In Table 1, the content of each component is the value relative to the polyamide resin composition as 100% by mass.

[0099]

[0100] Examples 1 to 5 all exhibit good tensile strength, fluidity, fatigue strength, and abrasion resistance. Comparative Example 1 exhibits poor abrasion resistance because the sizing agent coating the glass fibers does not contain a copolymer having acidic groups. Comparative Example 2 exhibits poor fatigue strength because the sizing agent coating the glass fibers does not contain a copolymer having acidic groups. The difference in results between Comparative Examples 1 and 2 is believed to be due to the difference in average fiber diameter of the glass fibers. Comparative Example 7 exhibits poor tensile strength and fatigue strength because the sizing agent coating the glass fibers does not contain a copolymer having acidic groups. Since Example 4 and Comparative Example 7 have the same polyamide resin composition, it is believed that the sizing agent composition affects the tensile strength and fatigue strength. Comparative Example 3 exhibits poor fatigue strength because the molecular weight distribution does not satisfy the requirements of the present invention. Comparative Examples 4 and 5 exhibit poor abrasion resistance because the proportion of polyamide resins with molecular weights of 30,000 or less is higher than in the present invention and the proportion of polyamide resins with molecular weights of 100,000 or more is lower than in the present invention. In Reference Example 6, the proportion of polyamide resin having a molecular weight of 30,000 or less is higher than that of the present invention, and the proportion of polyamide resin having a molecular weight of 100,000 or more is lower than that of the present invention, but since the relative viscosity and terminal amino group concentration are within specific ranges, the degree of deterioration in abrasion resistance is not so great.

[0101] The polyamide resin composition of the present invention is suitably used as a molded article for parts that require slidability.

Claims

1. A polyamide resin composition comprising an aliphatic polyamide resin (A) and glass fibers (B) coated with a sizing agent, wherein, for all polyamide resins in the polyamide resin composition, the ratio of the peak area of ​​polyamide resins having a molecular weight of 30,000 or less to the total area of ​​peaks calculated using gel permeation chromatography in terms of standard polymethyl methacrylate is 22.00 to 30.00 area %, and the ratio of the peak area of ​​polyamide resins having a molecular weight of 100,000 or more is 14.00 to 27.00 area %, the molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of all polyamide resins in the polyamide resin composition is 4.00 to 8.50, and the sizing agent comprises a polyurethane resin and a copolymer having an acidic group.

2. The polyamide resin composition according to claim 1, wherein the relative viscosity measured at 25°C in accordance with JIS K6920-2 when 1 g of the aliphatic polyamide resin (A) is dissolved in 100 mL of 96% concentrated sulfuric acid is 2.50 to 3.35, and the terminal amino group concentration of the aliphatic polyamide resin (A) is more than 15.00 μmol / g and less than 50.00 μmol / g.

3. The polyamide resin composition according to claim 1, comprising 68 to 88 mass% of the aliphatic polyamide resin (A) and 5 to 30 mass% of the glass fiber coated with the sizing agent (B) based on 100 mass% of the polyamide resin composition.

4. The polyamide resin composition according to claim 1, wherein the aliphatic polyamide resin (A) is an aliphatic homopolyamide resin (A-1).

5. The polyamide resin composition according to claim 4, wherein the aliphatic polyamide resin (A) is a combination of two or more kinds of aliphatic homopolyamide resins (A-1) having different terminal amino group concentrations.

6. The polyamide resin composition according to claim 4, wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-1) having a structural unit derived from an aminocarboxylic acid or a lactam.

7. The polyamide resin composition according to claim 4, wherein the aliphatic homopolyamide resin (A-1) is an aliphatic homopolyamide resin (A-1-2) having structural units derived from a reaction product of an aliphatic diamine and an aliphatic dicarboxylic acid.

8. The polyamide resin composition according to claim 6, wherein the aliphatic homopolyamide resin (A-1-1) is at least one selected from the group consisting of polyamide 6, polyamide 11 and polyamide 12.

9. The polyamide resin composition according to claim 7, wherein the aliphatic homopolyamide resin (A-1-2) is at least one selected from the group consisting of polyamide 56, polyamide 66, polyamide 410, polyamide 510, polyamide 610 and polyamide 612.

10. The polyamide resin composition according to claim 1, wherein the glass fibers (B) have an average fiber diameter of 5.0 to 12.0 μm.

11. The polyamide resin composition according to claim 1, wherein the glass fibers (B) have a number average fiber length of 200 to 350 μm.

12. The polyamide resin composition according to claim 1, wherein the glass fiber (B) has a weight average fiber length of 250 to 450 μm.

13. The polyamide resin composition according to claim 1, wherein the content of the copolymer having an acidic group is 0.5 to 10.0 mass % relative to 100 mass % of the sizing agent.

14. The polyamide resin composition according to claim 1, wherein the constituent units derived from the monomer having an acidic group account for 20 to 60 mass% of 100 mass% of all constituent units of the copolymer having an acidic group contained in the sizing agent.

15. The polyamide resin composition according to claim 1, wherein the structural unit derived from a monomer having an acidic group in the copolymer having an acidic group contained in the sizing agent is a structural unit derived from an unsaturated carboxylic acid and / or a carboxylic acid anhydride.

16. A molded article made from the polyamide resin composition according to any one of claims 1 to 15.

17. The molded product according to claim 16, which is used for parts requiring sliding properties.