Polyamide resin composition

Abstract

Provided is a polyamide resin composition which is shiny and has good mechanical properties such as tensile strength and impact resistance.　The polyamide resin composition according to the present invention comprises, in 100% by mass of the polyamide resin composition, 35%-90% by mass of a polyamide resin (A1) having a constituent unit derived from a reaction product of pentamethylenediamine and an aliphatic dicarboxylic acid, 0%-5% by mass of polyamide 6 (A2), and 5%-60% by mass of a reinforcing filler (B) coated with a sizing agent including a polyurethane resin.

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, and electrical and electronics.

[0003] Conventional polyamide resins have been made from fossil fuels. Recently, growing interest in environmental issues has led to a demand for environmentally friendly resins. Pentamethylenediamine can be obtained from biomass materials. Polyamide resin compositions containing polyamide 5X, which uses pentamethylenediamine, have been developed (see, for example, Patent Documents 1 to 4). Patent Document 1 describes a polyamide resin composition containing glass fibers and exhibiting excellent mechanical properties.

[0004] JP 2004-269634 A JP 2022-69966 A JP 2011-225630 A JP 2023-59853 A

[0005] However, the mechanical properties of the polyamide resin compositions disclosed in Patent Documents 1 to 4 have not yet been sufficiently investigated. Meanwhile, molded articles of polyamide resin compositions are often used in places where they are visible to the public, and therefore require good design. Therefore, an object of the present invention is to provide a polyamide resin composition that is glossy and has good mechanical properties such as tensile strength and impact resistance.

[0006] The present invention relates to the following, for example, to [1] to [7]. [1] A polyamide resin composition comprising, per 100% by mass of the polyamide resin composition, 35 to 90% by mass of a polyamide resin (A1) having structural units derived from a reaction product of pentamethylenediamine and an aliphatic dicarboxylic acid, 0 to 5% by mass of a polyamide 6 (A2), and 5 to 60% by mass of a reinforcing filler (B) coated with a sizing agent containing a polyurethane resin. [2] The polyamide resin composition of [1], comprising, per 100% by mass of the polyamide resin composition, 35 to 85% by mass of the polyamide resin (A1), 0.05 to 5% by mass of the polyamide 6 (A2), and 5 to 60% by mass of the reinforcing filler (B). [3] The polyamide resin composition of [1] or [2], comprising, per 100% by mass of the polyamide resin composition, 0.005 to 0.50% by mass of a colorant (C). [4] The polyamide resin composition of any one of [1] to [3], wherein the polyamide resin (A1) is at least one selected from the group consisting of polyamide 56, polyamide 59, polyamide 510, and polyamide 513. [5] The polyamide resin composition of any one of [1] to [4], wherein the reinforcing filler is a fibrous reinforcing filler. [6] The polyamide resin composition of any one of [1] to [5], wherein the polyamide resin composition contains 0.001 to 0.05 mass% of a lubricant (D). [7] A molded product of the polyamide resin composition of any one of [1] to [6].

[0007] The polyamide resin composition of the present invention has a glossy finish and good mechanical properties such as tensile strength and impact resistance.

[0008] The present invention relates to a polyamide resin composition comprising, relative to 100% by mass of the polyamide resin composition, 35 to 90% by mass of a polyamide resin (A1) having structural units derived from a reaction product of pentamethylenediamine and an aliphatic dicarboxylic acid, 0 to 5% by mass of polyamide 6 (A2), and 5 to 60% by mass of a reinforcing filler (B) coated with a sizing agent containing a polyurethane resin.

[0009] <Polyamide Resin (A1) Having Structural Units Derived from a Reaction Product of Pentamethylenediamine and Aliphatic Dicarboxylic Acid> The polyamide resin composition contains a polyamide resin (A1) (hereinafter also referred to as "polyamide resin (A1)") having structural units derived from a reaction product of pentamethylenediamine and aliphatic dicarboxylic acid. The polyamide resin (A1) is an aliphatic homopolyamide resin having structural units derived from a condensation product of pentamethylenediamine and aliphatic dicarboxylic acid, and is preferably an aliphatic homopolyamide resin based on structural units derived from a condensation product of pentamethylenediamine and aliphatic dicarboxylic acid. The diamine used in this polycondensation reaction contains pentamethylenediamine as an essential component, but may contain other diamines as long as the effects of the present invention are not impaired. Preferably, the polyamide resin does not contain other diamines.

[0010] It is more preferable that 50% by mass or more of the pentamethylenediamine in the polyamide resin (A1) is derived from a biomass raw material, based on 100% by mass of the pentamethylenediamine. The polyamide resin (A1) using the biomass-derived pentamethylenediamine is an environmentally friendly material because the raw material is plant-derived.

[0011] 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. Among these, non-alicyclic aliphatic dicarboxylic acids are preferred, and one selected from the group consisting of adipic acid, azelaic acid, sebacic acid, and tridecanedionic acid is more preferred, with adipic acid or sebacic acid being even more preferred.

[0012] The polyamide resin (A1) is preferably at least one selected from the group consisting of polyamide 56, polyamide 59, polyamide 510, and polyamide 513, more preferably at least one selected from the group consisting of polyamide 56 and polyamide 510, and even more preferably at least one selected from the group consisting of polyamide 56 and polyamide 510.

[0013] The relative viscosity of the polyamide resin (A1) is preferably 1.5 to 5.0, more preferably 2.0 to 4.1, and even more preferably 2.4 to 3.1. Having a viscosity within the above range improves moldability. The relative viscosity is measured in accordance with JIS K6920-2 by dissolving 1 g of polyamide resin in 100 ml of 96% concentrated sulfuric acid at 25°C.

[0014] The terminal amino group concentration of the polyamide resin (A1), as determined by dissolving the polyamide resin in a mixed solvent of phenol and methanol and subjecting it to neutralization titration, is preferably 30 μmol / g or more, more preferably 30 to 110 μmol / g, and even more preferably 30 to 70 μmol / g. By being in the above range, the interaction with the reinforcing filler is improved, resulting in improved mechanical properties.

[0015] The upper limit of the amount of polyamide resin (A1) in 100% by mass of the polyamide resin composition is 90% by mass, preferably 85% by mass, and more preferably 80% by mass. The lower limit of the amount of polyamide resin (A1) in 100% by mass of the polyamide resin composition is 35% by mass, preferably 40% by mass. The specific range of the amount of polyamide resin (A1) in 100% by mass of the polyamide resin composition is 35 to 90% by mass, preferably 35 to 85% by mass, and more preferably 40 to 80% by mass. When the amount of polyamide resin (A1) in the above range is used, the mechanical properties are improved and moldability is favorable.

[0016] <Polyamide 6 (A2)> The polyamide resin composition preferably contains polyamide 6 (A2) as an optional component. The incorporation of polyamide 6 (A2) is preferred from the viewpoint of dispersibility of various additives. Examples of polyamide 6 (A2) include ring-opening polymers of ε-caprolactam.

[0017] The relative viscosity of polyamide 6 (A2) is preferably 1.5 to 5.0, more preferably 1.9 to 3.9, and even more preferably 2.2 to 2.8. Having a viscosity within the above range improves moldability. The relative viscosity is measured in accordance with JIS K6920-2 by dissolving 1 g of polyamide resin in 100 ml of 96% concentrated sulfuric acid at 25°C.

[0018] The terminal amino group concentration of polyamide 6 (A2), as determined by dissolving the polyamide 6 in a mixed solvent of phenol and methanol and subjecting it to neutralization titration, is preferably 30 μmol / g or more, more preferably 30 to 110 μmol / g, and even more preferably 30 to 70 μmol / g. By being in this range, the interaction with the reinforcing filler is improved, resulting in improved mechanical properties.

[0019] The amount of polyamide 6 (A2) is 0 to 5 mass%, preferably 0.05 to 5 mass%, and more preferably 0.1 to 3 mass%, based on 100 mass% of the polyamide resin composition. When the amount of polyamide 6 (A2) is within the above range, the functions and properties of the polyamide resin (A1) are not impaired.

[0020] <Reinforcing filler (B) coated with a sizing agent containing polyurethane resin> The polyamide resin composition contains a reinforcing filler (B) coated with a sizing agent containing polyurethane resin (hereinafter also referred to as "reinforcing filler (B) coated with a sizing agent"). The reinforcing filler (B) coated with a sizing agent containing polyurethane resin is a component that imparts excellent sliding properties and mechanical properties to the polyamide resin composition.

[0021] [Reinforcing filler] Examples of reinforcing fillers include fibrous reinforcing fillers such as glass fiber, carbon fiber, graphite fiber, metal fiber, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, slag fiber, and boron fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, and silicon whisker; wollastonite, sepiolite, zonolite, elestadite, sericite, kaolin, mica, clay, bentonite, asbestos, talc, and silicates such as alumina silicate; swellable layered silicates such as montmorillonite and synthetic mica; metal compounds such as alumina, silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, and iron oxide; carbonates such as calcium carbonate, magnesium carbonate, and dolomite; sulfates such as calcium sulfate and barium sulfate; glass flakes, glass beads, ceramic beads, boron nitride, silicon carbide, calcium phosphate, and silica. These may be used alone or in combination of two or more.

[0022] Among reinforcing fillers, fibrous reinforcing fillers are preferred. Fiber refers to a shape with an aspect ratio (ratio of major axis / minor axis) of 10 or more. The reinforcing filler (B) may break when melt-kneaded with other components. Therefore, a preferred embodiment of a fibrous reinforcing filler in a polyamide resin composition includes a filler that breaks during melt-kneading and no longer meets the definition of "fiber" as defined herein, as long as it meets the definition of "fiber" as defined herein when blended. The cross-sectional shape of the fibrous reinforcing filler is not particularly limited, and examples include a perfect circle, a cocoon, an oval, a rectangle, or shapes similar thereto.

[0023] The average fiber diameter of the fibrous reinforcing filler is preferably 5.0 μm to 15.0 μm. When the average fiber diameter of the fibrous reinforcing filler is within the above range, the dispersion of the reinforcing fibers in the resin is improved, thereby ensuring mechanical strength. The average fiber diameter of the fibrous reinforcing filler 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 fibrous reinforcing filler (B) coated with a preferred embodiment of a sizing agent is also preferably within the same range.

[0024] When the cross section of the fibrous reinforcing filler 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 fibrous reinforcing filler during 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 fibrous reinforcing filler during this process. Therefore, the number-average fiber length of the fibrous reinforcing filler 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 fibrous reinforcing filler 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 fibrous reinforcing filler can be determined using image analysis software from images taken with a transmission microscope. The aspect ratio of the fibrous reinforcing filler 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 fibrous reinforcing filler coated with a sizing agent are also preferably in the same ranges as above. Note that "fibrous reinforcing filler coated with a sizing agent in a polyamide resin composition" refers to fibrous reinforcing filler coated with a sizing agent in a polyamide resin composition obtained by melt-kneading the respective components.

[0025] Among the fibrous reinforcing fillers, glass fiber, carbon fiber, and graphite fiber are preferred, and glass fiber is more preferred. Examples of the glass constituting the glass fiber include those having a composition such as A-glass, AR-glass, C-glass, D-glass, E-glass, H-glass, S-glass, T-glass, M-glass, and NE-glass.

[0026] The shape of the glass fiber is not particularly limited, and examples thereof include flat fiber and chopped strand.

[0027] [Polyurethane Resin] The polyurethane resin is a resin obtained by a urethane reaction between a polyol component and a polyisocyanate component.

[0028] <Polyol Component> Examples of the polyol component include polyester polyols (condensation polyester polyols, lactone polyester polyols), polycarbonate polyols, and polyether polyols.

[0029] 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.

[0030] 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.

[0031] 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).

[0032] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyoxypropylene glycol, and glycerin-based polyalkylene ether glycol.

[0033] <Polyisocyanate Component> Examples of the polyisocyanate include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] The polyisocyanate is preferably a diisocyanate having two isocyanato groups per molecule.

[0038] In the urethane reaction, a chain extender such as a polyhydric alcohol or a polyhydric amine may also be used.

[0039] [Other Optional Components of Sizing Agent] The sizing agent may contain additional components in addition to the polyurethane resin, such as a copolymer having an acidic group, a coupling agent, a lubricant, a nonionic surfactant, an antistatic agent, water, an organic solvent, etc.

[0040] 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).

[0041] 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, anhydrides, 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, the above-mentioned carboxylic acid anhydrides, etc. These may be used alone or in combination of two or more.

[0042] Examples of monomers that do not have an acidic group include styrene, ethylene, and acetylene.

[0043] The copolymer having an acidic group is preferably a copolymer of an unsaturated dicarboxylic acid and / or a carboxylic acid anhydride, methyl acrylate, and methyl methacrylate.

[0044] In a copolymer obtained by copolymerizing an unsaturated dicarboxylic acid and / or carboxylic acid anhydride with methyl acrylate and methyl methacrylate, the copolymerization ratio of the unsaturated dicarboxylic acid and / or carboxylic acid anhydride is preferably 20 to 60% by mass, and particularly preferably 25 to 55% by mass, from the viewpoints of reactivity and mechanical properties during the production of the copolymer. The copolymerization ratio of methyl acrylate is preferably 20 to 75% by mass, and particularly preferably 30 to 65% by mass, from the viewpoints of reactivity and mechanical properties during the production of the copolymer. Furthermore, the copolymerization ratio of methyl methacrylate is preferably 5 to 20% by mass, and particularly preferably 7 to 17% by mass, from the viewpoints of reactivity and mechanical properties during the production of the copolymer. The copolymerization ratio of a monomer not having an acidic group is preferably 10% by mass or less, and particularly preferably 1% by mass or less.

[0045] From the viewpoints of reactivity and mechanical properties during copolymer production, 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). 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 lubricants, nonionic surfactants, antistatic agents, etc. Examples of organic solvents include ethanol.

[0046] The content of each component in the sizing agent can be appropriately set depending on the properties of the reinforcing filler to be obtained.

[0047] [Coating] The reinforcing filler is coated with a sizing agent containing a polyurethane resin. The reinforcing filler is surface-treated by being coated with the sizing agent. "Coating" refers to the adhesion of the sizing agent to at least a portion of the surface of the reinforcing filler. The reinforcing filler may also be subjected to a bundling treatment using the sizing agent to combine two or more reinforcing filler strands into one. The bundling treatment can also be performed by applying the sizing agent to multiple reinforcing filler monofilaments formed by drawing molten glass from multiple nozzles, bundling them into a single reinforcing filler strand, and then winding them into a cake.

[0048] The reinforcing filler (B) coated with the sizing agent may be surface-treated with a further component, such as the further component contained in the sizing agent.

[0049] The reinforcing filler (B) coated with a sizing agent containing a polyurethane resin may contain, in addition to the above, the components described in JP 2014-231452 A. The reinforcing filler (B) coated with a sizing agent containing a polyurethane resin may be one type of component or a combination of two or more types of components.

[0050] 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%, and 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.

[0051] The upper limit of the amount of the reinforcing filler (B) coated with a bundling agent is 60% by mass, preferably 55% by mass, and more preferably 50% by mass, based on 100% by mass of the polyamide resin composition. The lower limit of the amount of the polyamide resin (A1) is 5% by mass, preferably 10% by mass, and more preferably 20% by mass, based on 100% by mass of the polyamide resin composition. The specific range of the amount of the reinforcing filler (B) coated with a bundling agent is 5 to 60% by mass, preferably 10 to 55% by mass, and more preferably 20 to 50% by mass, based on 100% by mass of the polyamide resin composition. The amount of the reinforcing filler (B) in this range is preferred from the viewpoints of mechanical properties and moldability.

[0052] <Colorant (C)> The polyamide resin composition preferably contains a colorant (C) as an optional component. The colorant (C) is a component whose main function is to color the polyamide resin composition. Examples of the colorant (C) include carbon black, nigrosine, titanium oxide, and iron oxide. These may be used alone or in combination of two or more.

[0053] The upper limit of the amount of colorant (C) blended is preferably 0.50 mass%, more preferably 0.40 mass%, and even more preferably 0.30 mass%, based on 100 mass% of the polyamide resin composition. The lower limit of the amount of colorant (C) blended is preferably 0.005 mass%, more preferably 0.05 mass%, and even more preferably 0.10 mass%, based on 100 mass% of the polyamide resin composition. The specific range of the amount of colorant (C) blended is preferably 0.005 to 0.50 mass%, more preferably 0.05 to 0.40 mass%, and even more preferably 0.10 to 0.30 mass%, based on 100 mass% of the polyamide resin composition. The amount of colorant (C) blended within the above range is preferred from the viewpoint of preventing bleed-out onto the surface of the molded article.

[0054] <Lubricant (D)> The polyamide resin composition preferably contains a lubricant (D) as an optional component. The lubricant is a substance that contributes to improving the releasability of the resin composition from a mold when molding the resin composition.

[0055] Examples of lubricants include compounds such as terminally modified polyalkylene glycols, phosphates or phosphites, higher fatty acid monoesters, higher fatty acids or their metal salts, carboxylic acid amides, ethylene bisamide compounds, low-molecular-weight polyethylene, magnesium silicate, and substituted benzylidene sorbitols. These may be used alone or in combination of two or more. Among these, higher fatty acids or their metal salts are preferred.

[0056] Examples of terminal-modified polyalkylene glycols include terminal-modified polyethylene glycols, terminal-modified polypropylene glycols, etc. More specific examples of phosphate esters and phosphites include aliphatic phosphate esters and aliphatic phosphites such as di(2-ethylhexyl)phosphate, tridecyl phosphite, tris(tridecyl)phosphite, and tristearyl phosphite, and aromatic phosphites such as triphenyl phosphite and diphenyl monodecyl phosphite.

[0057] Examples of higher fatty acid monoesters include myristyl myristate, stearyl stearate, behenyl behenate, oleyl oleate, and hexyldecyl myristate. Examples of higher fatty acids include myristic acid, palmitic acid, behenic acid, oleic acid, and arachidic acid. Examples of metal salts of higher fatty acids include zinc stearate, lithium stearate, calcium stearate, aluminum palmitate, and metal salts of the above-mentioned examples of higher fatty acids.

[0058] Examples of carboxylic acid amides include aliphatic monocarboxylic acid amides such as lauric acid amide, palmitic acid amide, oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ricinoleic acid amide, and 12-hydroxystearic acid amide; N-lauryl lauric acid amide, N-palmityl palmitic acid amide, N-oleyl palmitic acid amide, N-oleyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl stearic acid amide, N-stearyl oleic acid amide, N-stearyl erucic acid amide, and N-stearyl-12- N-substituted aliphatic monocarboxylic acid amides such as hydroxystearic acid amide, N-oleyl-12-hydroxystearic acid amide, methylol stearic acid amide, methylol behenic acid amide, and 12-hydroxystearic acid monoethanolamide; methylene bisstearic acid amide, methylene bislauric acid amide, methylene bis-12-hydroxystearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, ethylene bisoleic acid amide, ethylene bisstearic acid amide, ethylene biserucic acid amide; aliphatic carboxylic acid bisamides such as N,N'-behenic acid amide, ethylene bisisostearic acid amide, ethylene bis-12-hydroxystearic acid amide, butylene bisstearic acid amide, hexamethylene bisoleic acid amide, hexamethylene bisstearic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bis-12-hydroxystearic acid amide, N,N'-dioleyl sebacic acid amide, N,N'-dioleyl adipic acid amide, N,N'-distearyl adipic acid amide, and N,N'-distearyl sebacic acid amide; alicyclic carboxylic acid amides such as N,N'-dicyclohexanecarbonyl-1,4-diaminocyclohexane, 1,4-cyclohexanedicarboxamide, 1,4-cyclohexanedicarboxylic acid diaminocyclohexane, 1,2,3,4-butanetetracarboxylic acid tetracyclohexylamide, N,N'-bis(3-hydroxypropyl)-1,4-cubanedicarboxamide, N,N'-(1,4-cyclohexanediyl)bis(acetamide), and tris(methylcyclohexyl)propanetricarboxamide; 1,4-cyclohexanedicarboxylic acid dianilide, 1,Examples of aromatic carboxylic acid amides include 4-cyclohexanedicarboxylic acid dibenzylamide, trimesic acid tris(t-butylamide), trimesic acid tricyclohexylamide, trimesic acid tri(2-methylcyclohexylamide), trimesic acid tri(4-cyclohexylamide), 2,6-naphthalene acid dicarboxylic acid dicyclohexylamide, N,N'-dibenzylcyclohexane-1,4-dicarboxamide, N,N'-distearylisophthalic acid amide, N,N'-distearylterephthalic acid amide, m-xylylenebisstearic acid amide, and m-xylylenebis-12-hydroxystearic acid amide.

[0059] Examples of ethylene bisamide compounds include ethylene bisstearylamide and ethylene bispalmitylamide. Examples of low-molecular-weight polyethylene include those having a molecular weight in the range of 500 to 5000. Examples of magnesium silicate include those having an average particle size of 1 to 10 μm.

[0060] The substituted benzylidene sorbitols include those synthesized by dehydration condensation of sorbitol and a substituted benzaldehyde in the presence of an acid catalyst. These may be used alone or in combination of two or more.

[0061] The amount of lubricant (D) blended is preferably 0.001 to 0.05 mass%, more preferably 0.005 to 0.04 mass%, and even more preferably 0.01 to 0.03 mass%, based on 100 mass% of the polyamide resin composition. When the amount of lubricant (D) blended is within this range, moldability is improved, and it is preferable from the viewpoint of preventing the lubricant from bleeding out onto the surface of a molded article.

[0062] <Other Optional Components> The polyamide resin composition may contain optional components other than those described above, provided that the effects of the present invention are not impaired. Examples of optional components include resins other than the components (A1) and (A2), and functionality-imparting agents other than the components (B), (C), and (D).

[0063] Examples of resins other than component (A1) and component (A2) include aliphatic polyamide resins other than component (A1) and component (A2), 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-based resins.

[0064] When resins other than the component (A1) and the component (A2) are blended, their amount 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.

[0065] 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, release agents, antistatic agents, dispersants, flame retardants, flame retardant assistants, and spreading agents.

[0066] 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.

[0067] 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 organic 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.

[0068] The heat-resistant agent is preferably a combination of an inorganic compound and a nitrogen-containing compound, or an inorganic compound itself. Examples of the inorganic compound include metal halides and inorganic compounds other than metal halides.

[0069] 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). 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. The metal halide is more preferably potassium iodide and / or cuprous iodide, and even more preferably a mixture of potassium iodide and cuprous iodide.

[0070] Examples of inorganic compounds other than metal halides include metals, metal oxides, metal hydroxides, metal nitrides, metal phosphates, metal phosphites, metal carbonates, metal silicates, metal titanates, metal borates, metal sulfates, and metal nitrates.

[0071] Examples of the nitrogen-containing compound include melamine, benguanamine, dimethylol urea, and cyanuric acid.

[0072] 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%, and even more preferably 0.10 to 0.50 mass%, based on 100 mass% of the polyamide resin composition.

[0073] Examples of functionality-imparting agents other than those mentioned above include the components described in JP-A No. 2002-370551. Each optional component may be a single component or a combination of two or more components.

[0074] <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 kneader, 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.

[0075] [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.

[0076] 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.

[0077] <<Measurement method and evaluation>> ◯ was evaluated as pass, and × was evaluated as fail. (1) Average gloss A Type D2 test piece was prepared in accordance with ISO294-3, and the gloss was measured using a glossmeter (BYK, micro-TRI-gloss μ 4435) at an incident angle of 60° as specified in JIS Z 8741, and the gloss was calculated as the average value of a total of five points: the center of one test piece and four points 20 mm apart from the center, above, below, left and right. ◯: Average gloss is more than 45%, excellent gloss. ×: Average gloss is 45% or less, poor gloss.

[0078] (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 150 MPa or more, excellent tensile strength. ×: Tensile strength is less than 150 MPa, poor tensile strength.

[0079] (3) Charpy impact strength Type B test specimens were prepared in accordance with ISO 294-1, and were then V-notched in accordance with ISO 179 / 1eA. A Charpy impact test was carried out in an atmosphere at 23°C. ◯: Charpy impact strength was 6 kJ / m ２ Charpy impact strength is 6 kJ / m or more, and the impact resistance is excellent. ２ Less than 100%, poor impact resistance.

[0080] The components used in the examples and comparative examples are as follows. PA56: Polyamide 56, relative viscosity 2.78, terminal amino group concentration 49.7 μmol / g, manufactured by Cathay PA66: Polyamide 66, relative viscosity 2.65, terminal amino group concentration 52.9 μmol / g, manufactured by Asahi Kasei Corporation PA6: Polyamide 6, relative viscosity 2.47, terminal amino group concentration 44.5 μmol / g, manufactured by UBE Inc. Sizing agent-coated glass fiber T-249H: Round chopped ECS03T-249H Φ10.5 microns (manufactured by Nippon Electric Glass Co., Ltd.; average fiber diameter 10.5 μm, glass fibers coated with a sizing agent containing polyurethane resin.) Sizing agent-coated glass fiber T-275H: Round chopped ECS03T-275H Φ10.5 microns (manufactured by Nippon Electric Glass Co., Ltd.; average fiber diameter 10.5 μm, glass fibers coated with a sizing agent containing polyurethane resin.) Heat-resistant agent: cuprous iodide / potassium iodide = 1 / 6 (mass ratio) (mixture) Colorant: carbon black Lubricant: calcium stearate The relative viscosity of polyamide 56, polyamide 66, and polyamide 6 is the value measured at 25°C in accordance with JIS K6920-2, by dissolving 1g of polyamide resin in 100ml of 96% concentrated sulfuric acid. The terminal amino group concentration of polyamide 56, polyamide 66, and polyamide 6 was determined by dissolving the polyamide resin in a mixed solvent of phenol and methanol and performing neutralization titration. The average fiber diameter of the glass fiber is a catalog value.

[0081] [Examples 1 to 6, Comparative Examples 1 to 4] The components listed in Table 1 were melt-kneaded using a TEX34αIII twin-screw kneader manufactured by The Japan Steel Works, Ltd. to produce the desired polyamide resin composition pellets. Unless otherwise specified in the evaluation method, the obtained 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.

[0082]

[0083] The average gloss, tensile strength, and Charpy impact strength are all good in Examples 1 to 6. A comparison between Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, and Example 4 and Comparative Example 4, which are the same except for the presence or absence of the polyamide resin (A1) having a structural unit derived from a reaction product of pentamethylenediamine and an aliphatic dicarboxylic acid, shows that the Examples have better average gloss than the Comparative Examples under the same conditions.

[0084] The polyamide resin composition of the present invention is suitably used for molded articles that require gloss.

Claims

1. A polyamide resin composition comprising, based on 100% by mass of the polyamide resin composition, 35 to 90% by mass of polyamide resin (A1) having a structural unit derived from a reaction product of pentamethylenediamine and an aliphatic dicarboxylic acid, 0 to 5% by mass of polyamide 6 (A2), and 5 to 60% by mass of reinforcing filler (B) coated with a sizing agent containing a polyurethane resin.

2. The polyamide resin composition according to claim 1, comprising, based on 100% by mass of the polyamide resin composition, 35 to 85% by mass of the polyamide resin (A1), 0.05 to 5% by mass of the polyamide 6 (A2), and 5 to 60% by mass of the reinforcing filler (B).

3. The polyamide resin composition according to claim 1, which contains 0.005 to 0.50 mass% of the colorant (C) based on 100 mass% of the polyamide resin composition.

4. The polyamide resin composition according to claim 1, wherein the polyamide resin (A1) is at least one selected from the group consisting of polyamide 56, polyamide 59, polyamide 510 and polyamide 513.

5. The polyamide resin composition according to claim 1, wherein the reinforcing filler is a fibrous reinforcing filler.

6. The polyamide resin composition according to claim 1, which contains 0.001 to 0.05 mass% of a lubricant (D) based on 100 mass% of the polyamide resin composition.

7. A molded article made of the polyamide resin composition according to any one of claims 1 to 6.

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