Polyamide resin composition, molded article, and hollow molded article

Abstract

The present invention is a polyamide resin composition containing (A) an aliphatic polyamide resin and (B) an epoxy group-containing elastomer, wherein: the aliphatic polyamide resin (A) is an aliphatic polyamide resin in which the ratio of the number of methylene groups to the number of amide groups is more than 5.0; when the amino group amount of the aliphatic polyamide resin (A) blended in 1 kg of the resin composition is denoted as X mmol and the epoxy group amount of the epoxy group-containing elastomer (B) blended in 1 kg of the resin composition is denoted as Z mmol, formula (1): 1.05 ≤ [Z] / [X] ≤ 3.40, formula (2): 10.0 ≤ [X] ≤ 45.0, and formula (3): 20.0 ≤ [Z] ≤ 80.0 are satisfied; and a molded article including the polyamide resin composition can contribute to achievement of goals 9, 13, and the like of sustainable development goals (SDGs) by virtue of weight reduction of the molded article, from the viewpoint of contributing to reduction in resource usage.

Description

Polyamide resin composition, molded article, and blow molded article

[0001] The present invention relates to a polyamide resin composition, a molded article, and a blow molded article.

[0002] In the past, the main material for automotive piping tubing has been replaced by lightweight resins with excellent rust resistance, due to issues such as rust caused by road deicing agents, as well as the need to prevent global warming and conserve energy. Resins typically used for piping tubing include polyamide resins, saturated polyester resins, polyolefin resins, and thermoplastic polyurethane resins. Polyamide resins, among others, are often used for automotive piping tubing due to their excellent properties, including gas barrier properties, toughness, pinhole resistance, heat resistance, and oil resistance.

[0003] Materials used for automotive piping, such as coolant tubes, are required to have many properties, including impact resistance, resistance to deformation, toughness, and melt fluidity suitable for extrusion molding. Resins, including polyamide resins, are blended with other polymers to design compositions that meet the required properties. For example, blending with modified polyolefins is commonly used to impart impact resistance (Patent Documents 1 to 3).

[0004] However, when polyolefin is blended, polyamides tend to be prone to plastic deformation, losing their inherent resistance to deformation and strength. Therefore, in order to maintain resistance to deformation while improving properties such as impact resistance, it is necessary to consider a resin composition in which a component other than polyolefin is blended with a polyamide resin. For example, Patent Document 4 proposes a resin composition containing a polyamide resin, a rubber-containing graft polymer having an epoxy group, and a polymer containing a carboxy group and / or its derivative.

[0005] Japanese Patent Laid-Open No. 52-151348 Japanese Patent Laid-Open No. 59-24751 Japanese Patent Laid-Open No. 59-140258 Japanese Patent Laid-Open No. 2022-143428

[0006] However, Patent Document 4 only discusses impact resistance, heat resistance, and fluidity, and does not disclose technical data on tensile yield stress, which is an important index of durability against deformation. Furthermore, the resin composition of Patent Document 4 does not have sufficient impact resistance.

[0007] An object of the present invention is to provide a resin composition that is excellent in durability against deformation, impact resistance, toughness, and flowability.

[0008] The present invention relates to the following items [1] to

[15] . [1] A polyamide resin composition containing an aliphatic polyamide resin (A) and an epoxy group-containing elastomer (B), wherein the aliphatic polyamide resin (A) is an aliphatic polyamide resin having a ratio of the number of methylene groups to the number of amide groups of more than 5.0, and wherein, when the amount of amino groups in the aliphatic polyamide resin (A) blended per 1 kg of the resin composition is X mmol, and the amount of epoxy groups in the epoxy group-containing elastomer (B) blended per 1 kg of the resin composition is Z mmol, the polyamide resin composition satisfies the following formulas (1) to (3): 1.05≦[Z] / [X]≦3.40 (1) 10.0≦[X]≦45.0 (2) 20.0≦[Z]≦80.0 (3) [2] The polyamide resin composition according to item [1], wherein, when the amount of carboxyl groups in the aliphatic polyamide resin (A) blended per 1 kg of the resin composition is Y mmol, the following formula (4) is satisfied: 0.80≦[Z] / [Y]≦3.40 (4) [3] The polyamide resin composition according to [1] or [2], wherein the aliphatic polyamide resin (A) comprises at least one selected from the group consisting of polyundecane lactam (PA11), polylauryl lactam (PA12), polypentamethylene sebacamide (PA510), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), polynonamemethylene sebacamide (PA910), polynonamemethylene dodecamide (PA912), polydecamethylene sebacamide (PA1010), polydecamethylene dodecamide (PA1012), and polydodecamethylene dodecamide (PA1212). [4] The polyamide resin composition according to any one of [1] to [3], wherein the epoxy group-containing elastomer (B) contains, as an elastomer component, at least one selected from the group consisting of polyorganosiloxane-based elastomers, (meth)acrylic elastomers, styrene-based elastomers, and polyolefin-based elastomers.[5] The polyamide resin composition according to any one of [1] to [4], wherein the epoxy group-containing elastomer (B) has a core-shell structure, the core being at least one elastomer component selected from the group consisting of polyorganosiloxanes and polyalkyl(meth)acrylates, and the shell being an epoxy group-containing polymer. [6] The polyamide resin composition according to any one of [1] to [5], wherein the epoxy group-containing elastomer (B) is blended in an amount of 15.00 mass% to 30.00 mass% per 100 mass% of the polyamide resin composition. [7] The polyamide resin composition according to any one of [1] to [6], which is used for a hollow molded article that comes into contact with a coolant. [8] A molded article comprising the polyamide resin composition according to any one of [1] to [7]. [9] The molded article according to [8], which is cylindrical.

[10] The molded article according to [8] or [9], which is a tank, tube, hose, or pipe.

[11] A blow-molded article comprising a layer formed from the polyamide resin composition according to any one of [1] to [7].

[12] A blow-molded article comprising a layer formed from the polyamide resin composition according to any one of [1] to [7] as a barrier layer.

[13] A blow-molded article comprising an inner layer, an outer layer, and optionally one or more intermediate layers, wherein the outer layer is a layer formed from the polyamide resin composition according to any one of [1] to [7].

[14] A blow-molded article consisting solely of a layer formed from the polyamide resin composition according to any one of [1] to [7].

[15] A blow-molded article that comes into contact with a coolant, consisting solely of a layer formed from the polyamide resin composition according to any one of [1] to [7]. The present invention also relates to the following [1a] to [4a]. [1a] A Charpy impact strength of 80 kJ / m as measured according to a method in accordance with ISO 179 / 1eA. ２[2a] The polyamide resin composition according to any one of [1] to [7], having a tensile yield stress of 25.0 MPa or more (preferably 30.0 MPa or more), measured according to a method in accordance with ISO 527-1 and 2. [3a] The polyamide resin composition according to any one of [1] to [7], having a nominal tensile strain at break of 150% or more, measured according to a method in accordance with ISO 527-1 and 2. [4a] The polyamide resin composition according to any one of [1] to [7], wherein the retention rate (E2 / E1) of the nominal tensile strain at break E2 of test piece 2, measured in accordance with a method conforming to ISO 527-1 and 2, relative to the nominal tensile strain at break E1 of test piece 1, measured in accordance with a method conforming to ISO 527-1 and 2, is 50% or more, wherein the test piece 1 is obtained in accordance with ISO 294-1, and the test piece 2 is obtained by immersing the test piece 1 in a 50% by weight aqueous solution of ethylene glycol and heating it in an oven at 120°C for 1,000 hours.

[0009] The present invention provides a resin composition that is excellent in durability against deformation, impact resistance, toughness, and flowability.

[0010] As used herein, the content of each component in a composition refers to the total amount of each component in the composition unless otherwise specified, unless multiple substances corresponding to each component are present in the composition. The term "process" as used herein does not only include independent processes, but also encompasses processes that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. As used herein, amounts are rounded to the nearest digit. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after the range are included as the lower and upper limits. For example, "15.00 to 30.00% by mass" means "15.00% by mass or more and 30.00% by mass or less." As used herein, "PA" means "polyamide."

[0011] [Polyamide Resin Composition] The polyamide resin composition contains an aliphatic polyamide resin (A) and an epoxy group-containing elastomer (B). The aliphatic polyamide resin (A) is an aliphatic polyamide resin having a ratio of the number of methylene groups to the number of amide groups of more than 5.0. When the amount of amino groups in the aliphatic polyamide resin (A) blended in 1 kg of the polyamide resin composition is X mmol, the polyamide resin composition satisfies the following formula (2). When the amount of epoxy groups in the epoxy group-containing elastomer (B) blended in 1 kg of the polyamide resin composition is Z mmol, the polyamide resin composition satisfies the following formula (3). Furthermore, the variables X and Z satisfy the following formula (1): 1.05≦[Z] / [X]≦3.40 (1) 10.0≦[X]≦45.0 (2) 20.0≦[Z]≦80.0 (3)

[0012] The polyamide resin composition has excellent fluidity. Here, "excellent fluidity" means excellent melt fluidity suitable for various molding methods, and preferably melt fluidity suitable for extrusion molding.

[0013] Furthermore, the polyamide resin composition may have excellent resistance to hydrolysis in addition to durability against deformation, impact resistance, toughness, and fluidity.

[0014] Furthermore, a molded article containing the polyamide resin composition can contribute to achieving Goals 9, 13, and the like of the SDGs (Sustainable Development Goals) from the viewpoint of contributing to a reduction in resource consumption by reducing the weight of the molded article.

[0015] [Aliphatic polyamide resin (A)] The aliphatic polyamide resin (A) is an aliphatic polyamide resin having a ratio of the number of methylene groups to the number of amide groups of more than 5.0. ２ ] / [NHCO].

[0016] The polyamide resin is ２ When the aliphatic polyamide resin (A) is composed solely of an aliphatic polyamide resin having a [CH ] / [NHCO] of 5.0 or less, the hydrolysis resistance and extrusion moldability tend to be poor.２ ] / [NHCO] is preferably 6.0 or more and 14.0 or less, more preferably 8.0 or more and 13.0 or less, and even more preferably 10.0 or more and 12.0 or less.

[0017] Aliphatic polyamide resins include aliphatic homopolyamide resins and aliphatic copolyamide resins. Aliphatic homopolyamide resins are polyamide resins composed of one type of structural unit derived from an aliphatic monomer. Aliphatic homopolyamide resins may be composed of at least one type of lactam and an aminocarboxylic acid, which is a hydrolyzate of the lactam, or may be composed of a combination of one type of diamine and one type of dicarboxylic acid. Aliphatic copolyamide resins are polyamide resins composed of two or more structural units derived from aliphatic monomers. Aliphatic copolyamide resins are copolymers of two or more types selected from the group consisting of a combination of a diamine and a dicarboxylic acid, and a lactam and an aminocarboxylic acid. Here, a combination of a diamine and a dicarboxylic acid is considered to be one type of monomer, with one type of diamine and one type of dicarboxylic acid being the combination.

[0018] Specific examples of the aliphatic polyamide resin (A) include (A1) to (A3). (A1) [CH ２ ] / [NHCO] is more than 5.0; (A2) [CH ２ an aliphatic copolyamide resin using at least two raw material monomers (constituent repeating units) that form an aliphatic homopolyamide having a [CH ２ At least one raw material monomer (constituent repeating unit) forming an aliphatic homopolyamide having a [CH ２ An aliphatic copolyamide resin using as at least one component a raw material monomer (constituent repeating unit) that forms an aliphatic homopolyamide having a [N-(N-HCO)] / [NHCO] of 5.0 or less.

[0019] [CH ２Examples of aliphatic homopolyamide resins having a .OMEGA. / .OMEGA.NHCO ratio of more than 5.0 include polyenantholactam (PA7), polyundecane lactam (PA11), polylauryllactam (PA12), polytetramethylene azelamide (PA49), polytetramethylene sebacamide (PA410), polytetramethylene dodecamide (PA412), polypentamethylene adipamide (PA56), polypentamethylene suberamide (PA58), Polypentamethylene azelamide (PA59), polypentamethylene sebacamide (PA510), polypentamethylene dodecamide (PA512), polyhexamethylene suberamide (PA68), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene undecamide (PA611), polyhexamethylene dodecamide (PA612), polyhexamethylene tetradecamide ( PA614), polyhexamethylene hexadecamide (PA616), polyhexamethylene octadecamide (PA618), polynonameethylene adipamide (PA96), polynonameethylene suberamide (PA98), polynonameethylene azelamide (PA99), polynonameethylene sebacamide (PA910), polynonameethylene dodecamide (PA912), polydecamethylene adipamide (PA106), polydecamethylene suberamide (PA108), polydecamethylene azelamide (PA109), polydecamethylene sebacamide (PA1010), polydecamethylene dodecamide (PA1012), polydodecamethylene adipamide (PA126), polydodecamethylene suberamide (PA128), polydodecamethylene azelamide (PA129), polydodecamethylene sebacamide (PA1210), polydodecamethylene dodecamide (PA1212), and the like.

[0020] [CH ２ The aliphatic copolyamide resin having a ratio of [CH ２In addition to copolymers using several raw material monomers that form aliphatic homopolyamide resins with a [NHCO] / [NHCO] ratio of more than 5.0, caprolactam / hexamethylenediaminoazelaic acid copolymer (PA6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (PA6 / 610), caprolactam / hexamethylenediaminoundecanedicarboxylic acid copolymer (PA6 / 611), caprolactam / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 612), caprolactam / amino Examples thereof include noundecanoic acid copolymer (PA6 / 11), caprolactam / lauryllactam copolymer (PA6 / 12), caprolactam / hexamethylenediaminoadipic acid / lauryllactam copolymer (PA6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymer (PA6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymer (PA6 / 66 / 612).

[0021] [CH ２ Examples of aliphatic homopolyamide resins having a [N / HCO] ratio of 5.0 or less include polycaprolactam (PA6), polytetramethylene adipamide (PA46), and polyhexamethylene adipamide (PA66).

[0022] From the viewpoints of economy and availability, the aliphatic polyamide resin (A) is selected from polyundecane lactam (PA11), polylauryl lactam (PA12), polypentamethylene sebacamide (PA510), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), polynonamethylene sebacamide (PA910), polynonamethylene dodecamide (PA912), polydecamethylene sebacamide (PA1010), polydecamethylene dodecamide (PA1012), and polydodecamethylene It is preferable that the polymer contains at least one selected from the group consisting of polyundecane lactam (PA11), polylauryllactam (PA12), polypentamethylene sebacamide (PA510), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), and polydecamethylene sebacamide (PA1010), and it is particularly preferable that the polymer contains polyundecane lactam (PA11) and / or polylauryllactam (PA12).

[0023] When the amount of amino groups per 1 kg of the aliphatic polyamide resin (A) is [A1] (mmol / kg), [A1] is preferably 10.0 mmol / kg or more and 100 mmol / kg or less, more preferably 12.0 mmol / kg or more and 80.0 mmol / kg or less, and even more preferably 14.0 mmol / kg or more and 60.0 mmol / kg or less. The amount of amino groups [A1] can be measured by dissolving the aliphatic polyamide resin (A) in a phenol / methanol mixed solution and titrating with 0.02 N hydrochloric acid.

[0024] Furthermore, when the amount of carboxy groups per 1 kg of the aliphatic polyamide resin (A) is [A2] (mmol / kg), [A2] is preferably 10.0 mmol / kg or more and 100 mmol / kg or less, more preferably 15.0 mmol / kg or more and 80.0 mmol / kg or less, and even more preferably 20.0 mmol / kg or more and 70.0 mmol / kg or less. The amount of carboxy groups [A2] can be measured by dissolving the aliphatic polyamide resin (A) in benzyl alcohol and titrating the resultant solution with 0.05 N sodium hydroxide solution.

[0025] Aliphatic polyamide resin (A) can be produced by polymerization reaction. For example, it can be produced by polymerizing or copolymerizing raw materials for the aliphatic polyamide resin using known methods such as melt polymerization, solution polymerization, or solid-state polymerization. Examples of production equipment for the aliphatic polyamide resin (A) include known polyamide production equipment, such as batch reactors, single- or multi-vessel continuous reactors, tubular continuous reactors, kneading reaction extruders such as single-screw kneading extruders and twin-screw kneading extruders. Here, in the production of the aliphatic polyamide resin (A), in addition to the raw materials for the aliphatic polyamide resin (A), additional amines (monoamines, diamines, etc.) and / or additional carboxylic acids (monocarboxylic acids, dicarboxylic acids, etc.) may be added and polymerized or copolymerized. The additional amines and additional carboxylic acids can be appropriately selected from known components. The additional amines and / or additional carboxylic acids can be added at any stage during polymerization or at any stage during melt kneading after polymerization. This allows the amount of amino groups and / or carboxyl groups in the aliphatic polyamide resin (A) to be adjusted. The amount of amino groups and / or carboxyl groups in the aliphatic polyamide resin (A) can be adjusted by adjusting the molecular weight of the aliphatic polyamide resin (A).

[0026] The aliphatic polyamide resin (A) may be a single component or a combination of two or more components.

[0027] [Epoxy Group-Containing Elastomer (B)] The epoxy group-containing elastomer (B) is any elastomer as long as it has an epoxy group and contains an elastomer component.

[0028] The elastomer component in the epoxy group-containing elastomer (B) may be at least one selected from the group consisting of polyorganosiloxane elastomers, (meth)acrylic elastomers, styrene elastomers, and polyolefin elastomers.

[0029] The polyorganosiloxane elastomer is an elastomer having a polyorganosiloxane skeleton. Examples of monomer units contained in the polyorganosiloxane elastomer include hexamethyltricyclosiloxane, octamethylcyclosiloxane, decamethylpentacyclosiloxane, dodecamethylhexacyclosiloxane, trimethyltriphenylsiloxane, tetramethylphenylcyclotetrasiloxane, and octaphenylcyclotetrasiloxane.

[0030] Examples of (meth)acrylic elastomers include elastomers obtained by polymerizing a (meth)acrylic acid ester with a crosslinkable monomer. Examples of (meth)acrylic acid esters include monofunctional (meth)acrylic acid ester compounds such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of the crosslinkable monomer include vinyl compounds such as butylene di(meth)acrylate, ethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, oligoethylene glycol di(meth)acrylate, trimethylolpropane di(meth)acrylate, and trimethylolpropane tri(meth)acrylate; and allyl compounds such as allyl (meth)acrylate, diallyl maleate, diallyl fumarate, diaryl ammonium nitrate, monoallyl maleate, monoallyl fumarate, and triallyl cyanurate; and compounds having a bifunctional unsaturated bond.

[0031] Examples of styrene-based elastomers include copolymers of styrene and conjugated diene hydrocarbons. Examples of conjugated diene hydrocarbons include butadiene, isoprene, and 1,3-pentadiene. Specific examples of styrene-based elastomers include copolymers of styrene and butadiene (SBS), copolymers of styrene and isoprene (SIS), and hydrogenated resins (SEBS, SEPS) obtained by hydrogenating the copolymers.

[0032] Examples of polyolefin-based elastomers include copolymers obtained by copolymerizing an α-olefin and, optionally, an unsaturated monomer copolymerizable with the α-olefin. Examples of α-olefins include ethylene, propylene, 1-butene, and 1-pentene. Examples of unsaturated monomers copolymerizable with the α-olefin include vinyl ether compounds; vinyl ester compounds such as vinyl acetate and vinyl propionate; (meth)acrylic acid ester compounds; and acrylonitrile. Specific examples of (meth)acrylic acid ester compounds are as described above for the monofunctional (meth)acrylic acid ester compounds. Specific examples of polyolefin-based elastomers include ethylene propylene rubber.

[0033] The elastomer component in the epoxy group-containing elastomer (B) preferably contains at least one selected from the group consisting of polyorganosiloxane-based elastomers, (meth)acrylic elastomers, styrene-based elastomers, and polyolefin-based elastomers, more preferably at least one selected from the group consisting of polyorganosiloxane-based elastomers and (meth)acrylic elastomers, and particularly preferably a composite elastomer of a polyorganosiloxane-based elastomer and a (meth)acrylic elastomer.

[0034] The method for introducing epoxy groups into the epoxy group-containing elastomer (B) is not particularly limited. They may be incorporated into the main chain of the elastomer component, or the epoxy groups may be grafted onto the elastomer component. For example, the epoxy group-containing elastomer (B) may be a copolymer of a monomer constituting the elastomer component, a compound having an epoxy group and an unsaturated bond, and optionally, an additional monomer copolymerizable with the monomer and / or compound. Examples of the compound having an epoxy group and an unsaturated bond include epoxy group-containing (meth)acrylic ester compounds such as glycidyl acrylate and glycidyl methacrylate. When the elastomer component is a styrene-based elastomer, the epoxy group-containing elastomer (B) may be obtained by epoxidizing the unsaturated double bond of the diene component.

[0035] The epoxy group-containing elastomer (B) may also be an elastomer having a core-shell structure. Examples of elastomers having a core include elastomers having an elastomer component as the core and an epoxy group-containing polymer as the shell. Elastomers having a core-shell structure can be obtained by graft copolymerizing a monomer component, a compound having an epoxy group and an unsaturated bond, onto a core polymer. Examples of the core polymer include the elastomer components described above. For example, the epoxy group-containing elastomer (B) can be obtained by graft polymerizing a compound having an epoxy group and an unsaturated bond onto an elastomer component containing a polyorganosiloxane-based elastomer (preferably a composite elastomer component of polyorganosiloxane and polyalkyl(meth)acrylate).

[0036] Commercially available epoxy group-containing elastomers (B) include "Metablen (registered trademark) S-2200" manufactured by Mitsubishi Chemical Corporation, "Lotader (registered trademark) AX8900, AX8700" manufactured by Arkema, "Bondfast (registered trademark)" manufactured by Sumitomo Chemical Co., Ltd., "ELVALOY (registered trademark)" manufactured by Dow Mitsui Polychemicals, "Paraloid (registered trademark)" manufactured by Rohm and Haas, and "Epofriend (registered trademark)" manufactured by Daicel Chemical Industries, Ltd.

[0037] <Preferred embodiment> The epoxy group-containing elastomer (B) preferably contains at least one elastomer component selected from the group consisting of a polyorganosiloxane elastomer, a (meth)acrylic elastomer, a styrene elastomer, and a polyolefin elastomer, preferably a polyorganosiloxane elastomer and an elastomer component, and particularly preferably at least one elastomer component selected from the group consisting of a polyorganosiloxane elastomer and a (meth)acrylic elastomer. Furthermore, the epoxy group-containing elastomer (B) preferably has a core-shell structure, the core being at least one elastomer component selected from the group consisting of a polyorganosiloxane and a polyalkyl(meth)acrylate, and the shell being an epoxy group-containing polymer.

[0038] When the amount of epoxy groups per 1 kg of the epoxy group-containing elastomer (B) is [B1] (mmol / kg), [B1] is preferably 80 mmol / kg or more and 500 mmol / kg or less, and particularly preferably 100 mmol / kg or more and 360 mmol / kg or less. The amount of epoxy groups [B1] can be determined by measuring the epoxy equivalent in accordance with JIS K7236 and calculating the reciprocal thereof.

[0039] In addition, for the epoxy group-containing elastomer (B), the descriptions in JP-A-2022-143428, JP-A-2019-38880, and WO 2021 / 225153 can be referred to.

[0040] The epoxy group-containing elastomer (B) may be one component or a combination of two or more components.

[0041] [Optional Additive (C)] The polyamide resin composition may contain an optional additive (C) as a component other than the aliphatic polyamide resin (A) and the epoxy group-containing elastomer (B). Examples of the optional additive (C) include antioxidants, colorants, heat stabilizers, UV absorbers, light stabilizers, weather resistance agents, lubricants, inorganic fillers, antistatic agents, flame retardants, crystallization accelerators, plasticizers, and lubricants.

[0042] Examples of the antioxidant include phenol-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and amine-based antioxidants.

[0043] Examples of phenol-based antioxidants include hindered phenol-based antioxidants. In this specification, hindered phenol refers to a compound having a substituent at the ortho-position (hereinafter also referred to as "o-position") of the phenolic hydroxyl group. The substituent at the o-position is not particularly limited, but examples include alkyl groups, alkoxy groups, and halogens. Among these, alkyl groups such as methyl groups, ethyl groups, n-propyl groups, i-propyl groups, n-butyl groups, sec-butyl groups, i-butyl groups, and tert-butyl groups are preferred, with bulky i-propyl groups, sec-butyl groups, i-butyl groups, and tert-butyl groups being more preferred, and tert-butyl groups being most preferred. Furthermore, with regard to the o-position, it is preferable that both of the two o-positions relative to the phenolic hydroxyl group have a substituent.

[0044] Examples of hindered phenols having a tert-butyl group at the o-position include N,N'-(hexane-1,6-diyl)bis[4-hydroxy-3,5-bis(tert-butyl)benzenepropanamide (Irganox (registered trademark) 1098; manufactured by BASF Japan Ltd.), pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4'-hydroxyphenyl)propionate (Irganox (registered trademark) 1010; manufactured by BASF Japan Ltd.), and ethylenediaminetetraacetic acid ester (ethylenediaminetetraacetic acid ester). Examples of suitable hydroxyalkyl groups include bis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-tolyl)propionate] (Irganox (registered trademark) 245; manufactured by BASF Japan Ltd.), 3,9-bis[2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy]-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane (Sumilizer (registered trademark) GA-80; manufactured by Sumitomo Chemical Co., Ltd.), and the like.

[0045] As the phosphorus-based antioxidant, a phosphite compound of a hindered phenol or a hypophosphite compound of a hindered phenol is preferred, a phosphite compound of a hindered phenol having a tert-butyl group at the o-position or a hypophosphite compound of a hindered phenol having a t-butyl group at the o-position is more preferred, and a phosphite compound of a hindered phenol having a t-butyl group at the o-position is even more preferred. These may be commercially available products, and a specific example of a phosphite compound of a hindered phenol having a t-butyl group at the o-position is tris(2,4-di-tert-butylphenyl)phosphite (Irgafos (registered trademark) 168; manufactured by BASF Japan Ltd.). Specific examples of hypophosphite ester compounds of hindered phenols having a tert-butyl group at the o-position include 3,9-bis(2,6-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane (ADK STAB (registered trademark) PEP-36; manufactured by ADEKA Corporation), and a reaction product of biphenyl, phosphorus trichloride, and 2,4-di-tert-butylphenol, which contains p,p,p',p'-tetrakis(2,4-di-tert-butylphenoxy)-4,4' (or 3',4)-biphenyldiphosphine as the main component (Hostanox (registered trademark) P-EPQ (registered trademark) P; manufactured by Clariant Japan K.K.).

[0046] Examples of sulfur-based antioxidants include pentaerythrityl tetrakis(3-laurylthiopropionate) (Sumilizer (registered trademark) TP-D manufactured by Sumitomo Chemical Co., Ltd.), distearyl-3,3-thiodipropionate, didodecyl(3,3′-thiodipropionate), and 4,4′-thiobis(6-t-butyl-3-methylphenol).

[0047] Examples of the amine-based antioxidant include 4,4'-bis(α,α-dimethylbenzyl)diphenylamine (DCD), octylated diphenylamine (ODPA), styrenated diphenylamine (SDPA), etc. Furthermore, a commercially available amine-based antioxidant is OKABEST (registered trademark) CLH56 (a mixture of 4,4'-bis(α,α-dimethylbenzyl)diphenylamine and other amine compounds) manufactured by OKA-Tec GmbH.

[0048] Examples of colorants include known colorants such as carbon black, black titanium oxide, inorganic dyes, organic dyes, inorganic pigments, and organic pigments.

[0049] The optional additives (C) other than the antioxidant and the colorant can be appropriately selected from components known to those skilled in the art.

[0050] The optional additive (C) preferably includes an antioxidant. Each optional additive (C) may be a single component or a combination of two or more components. For example, the optional additive (C) may include one or more antioxidants and one or more heat-resistant additives.

[0051] [Amount of Functional Groups in Aliphatic Polyamide Resin (A) and Epoxy Group-Containing Elastomer (B)] When the amount of amino groups in the aliphatic polyamide resin (A) blended per 1 kg of the polyamide resin composition is X mmol, and the amount of epoxy groups in the epoxy group-containing elastomer (B) blended per 1 kg of the polyamide resin composition is Z mmol, the polyamide resin composition satisfies formula (1): 1.05≦[Z] / [X]≦3.40. If [Z] / [X] is less than 1.05, the polyamide resin composition has high fluidity and is unsuitable for various molding methods. If [Z] / [X] is greater than 3.40, the fluidity and toughness are poor. [Z] / [X] is preferably 1.15 or more and 3.00 or less, and particularly preferably 1.25 or more and 2.70 or less. [Z] / [X] may also be 1.80 or more and 2.70 or less.

[0052] In the polyamide resin composition, the variable X satisfies the formula (2): 10.0≦[X]≦45.0. When [X] is less than 10.0, the hydrolysis resistance is poor. When [X] is more than 45.0, the reactivity with the epoxy group-containing elastomer (B) is high. As a result, the fluidity of the polyamide resin composition is reduced, making it unsuitable for various molding methods. [X] is preferably 13.0 or more and 30.0 or less, and particularly preferably 16.0 or more and 28.0 or less. [X] may be 19.0 or more and 28.0 or less.

[0053] In the polyamide resin composition, the variable Z satisfies the formula (3): 20.0≦[Z]≦80.0. When [Z] is less than 20.0, the reactivity with polyamide resin is low. As a result, the fluidity of the polyamide resin composition is high, making it unsuitable for various molding methods. When [Z] is more than 80.0, the reactivity with polyamide is high. As a result, the fluidity of the polyamide resin composition is low, making it unsuitable for various molding methods. [Z] is preferably 20.3 or more and 60.0 or less, and particularly preferably 20.5 or more and 40.0 or less. [Z] may be 25.0 or more and 50.0 or less, 30.0 or more and 48.0 or less, or 32.0 or more and 46.0 or less.

[0054] When the amount of carboxyl groups in the aliphatic polyamide resin (A) blended in 1 kg of the polyamide resin composition is Y mmol, the polyamide resin composition preferably satisfies formula (4): 0.80≦[Z] / [Y]≦3.40. When [Z] / [Y] is within this range, the polyamide resin composition has better fluidity and is more suitable for various molding methods. [Z] / [Y] is preferably 1.00 or more and 3.00 or less, and particularly preferably 1.10 or more and 2.80 or less. [Z] / [Y] may also be 1.50 or more and 2.70 or less.

[0055] [Contents and Blending Ratios] The amounts of each component in the polyamide resin composition are as follows. The polyamide resin composition preferably contains 15.00% by mass or more and 30.00% by mass or less of the epoxy group-containing elastomer (B), and particularly preferably 20.00% by mass or more and 30.00% by mass or less, based on 100% by mass of the polyamide resin composition. The blending amount of the epoxy group-containing elastomer (B) may be 24.00% by mass or more and 29.00% by mass or less. Such a blending ratio can improve the flowability of the polyamide resin composition and the mechanical properties of molded articles containing the polyamide resin composition. Furthermore, blending the epoxy group-containing elastomer (B) in the blending ratio described above allows the epoxy groups of the epoxy group-containing elastomer (B) to react with the terminal amino groups and / or carboxyl groups of the aliphatic polyamide resin (A) to form a composite resin of the aliphatic polyamide resin (A) and the epoxy group-containing elastomer (B), thereby improving the mechanical properties of molded articles containing the polyamide resin composition.

[0056] The blending ratio of the aliphatic polyamide resin (A) relative to 100% by mass of the polyamide resin composition is preferably 70.00% by mass or more, more preferably 71.00% by mass or more and 85.00% by mass or less, and particularly preferably 71.00% by mass or more and 80.00% by mass or less.

[0057] The content of the optional additive (C) relative to 100% by mass of the polyamide resin composition is preferably 0% by mass or more and 10.00% by mass or less, and particularly preferably 0.20% by mass or more and 5.00% by mass or less, with the remainder being the aliphatic polyamide resin (A), the epoxy group-containing elastomer (B), and a partial reaction product of the aliphatic polyamide resin (A) and the epoxy group-containing elastomer (B).

[0058] [Characteristics of Polyamide Resin Composition] The polyamide resin composition has a Charpy impact strength of 80 kJ / m as measured by a method in accordance with ISO 179 / 1eA. ２ A polyamide resin composition having such a Charpy impact strength is excellent in impact resistance. The Charpy impact strength is preferably 80 kJ / m or more.２ 150kJ / m or more ２ Preferably, it is 96 kJ / m or less. ２ More than 130kJ / m ２ The following is particularly preferred: For the method of measuring the Charpy impact strength, the method described in the Examples can be referred to.

[0059] The polyamide resin composition preferably has a tensile yield stress of 25.0 MPa or more, particularly preferably 30.0 MPa or more, measured according to a method in accordance with ISO 527-1 and 2. Polyamide resin compositions having such a tensile yield stress have excellent impact resistance. The tensile yield stress is preferably 25.0 MPa or more and 45.0 MPa or less, more preferably 25.0 MPa or more and 40.0 MPa or less, and particularly preferably 30.0 MPa or more and 40.0 MPa or less. The method for measuring the tensile yield stress can be referred to the method described in the Examples.

[0060] The polyamide resin composition preferably has a nominal tensile strain at break of 150% or more, measured according to a method in accordance with ISO 527-1 and 2. Polyamide resin compositions having such a nominal tensile strain at break have good toughness. The nominal tensile strain at break is preferably 150% or more and 300% or less, more preferably 120% or more and 200% or less, and particularly preferably 150% or more and 200% or less. The nominal tensile strain at break can be measured by referring to the method described in the Examples.

[0061] The polyamide resin composition preferably satisfies a nominal tensile strain at break retention of 50% or more. Here, "nominal tensile strain at break retention" refers to the ratio (E2 / E1) of the nominal tensile strain at break E2 of test piece 2 measured in accordance with ISO 527-1 and 2 to the nominal tensile strain at break E1 of test piece 1 measured in accordance with ISO 527-1 and 2. The test piece 1 is obtained in accordance with ISO 294-1. The test piece 2 is obtained by immersing the test piece 1 in a 50% by weight aqueous solution of ethylene glycol and heating it in an oven at 120°C for 1,000 hours. A polyamide resin composition having a nominal tensile strain at break retention of 50% or more has excellent hydrolysis resistance. The nominal tensile strain at break retention is preferably 50% to 150%, and particularly preferably 70% to 130%. The method for measuring the retention rate of nominal tensile strain at break can be referred to the method described in the Examples.

[0062] [Method for Producing Polyamide Resin Composition] The method for producing the polyamide resin composition is not particularly limited, and may include a method including a step of mixing an aliphatic polyamide resin (A), an epoxy group-containing elastomer (B), and an optional additive (C). A known melt-kneader can be used to mix the components. Examples of known melt-kneaders include a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader, and a mixing roll. Specific methods for mixing the components include a method in which all raw materials are blended and then melt-kneaded using a twin-screw extruder; a method in which some raw materials are blended and then melt-kneaded, and the remaining raw materials are further blended and melt-kneaded; or a method in which some raw materials are blended and then the remaining raw materials are mixed using a side feeder during melt-kneading.

[0063] [Uses of Polyamide Resin Composition] The polyamide resin composition can be used to produce molded articles using known methods. Specifically, the polyamide resin composition can be used to produce molded articles by injection molding, extrusion molding, press molding, blow molding, rotational molding, etc. In particular, since the polyamide resin composition has appropriate fluidity when melted, it can be suitably used to produce molded articles by molding methods that require a certain degree of viscosity, such as extrusion molding and blow molding.

[0064] The polyamide resin composition is preferably used for a blown molded article that comes into contact with a coolant. The coolant and the blown molded article will be described later.

[0065] [Molded Article Comprising Polyamide Resin Composition] The molded article comprising the polyamide resin composition (hereinafter, sometimes simply referred to as "molded article") may have any shape. Examples of the shape of the molded article include a hollow shape (including a cylindrical shape (tube, hose, pipe) and a cylindrical shape with a bottom (tank, bottle)), a film shape (including a plate shape and a sheet shape), and a circular shape. The molded article may also have a corrugated region. The corrugated region is a region formed in a corrugated shape, a bellows shape, an accordion shape, a corrugated shape, or a corrugated shape. When the molded article has a film shape, it may be post-processed to have a hollow shape.

[0066] The molded article can be produced by the above-mentioned molding method of the polyamide resin composition. The corrugated region can be formed by molding a hollow molded article and then subsequently molding it into a predetermined corrugated shape. The hollow molded article can be fitted with necessary parts such as connectors or bent into an L-shape, a U-shape, or the like.

[0067] The molded article is preferably hollow, particularly preferably cylindrical, and is preferably in the form of a tank, tube, hose, or pipe.

[0068] [Hollow Molded Article] The hollow molded article is a molded article having a hollow shape. The hollow molded article includes a layer formed from a polyamide resin composition. In the hollow molded article, the layer formed from the polyamide resin composition may be present as a barrier layer. Here, the "barrier layer" means a layer that is difficult to permeate with fluids, particularly coolants.

[0069] The number of layers in the blown molded article is arbitrary as long as a layer formed from the polyamide resin composition is present. That is, the blown molded article may be a single-layer structure consisting of only a layer formed from the polyamide resin composition. Alternatively, the blown molded article may be a multilayer structure including a layer formed from the polyamide resin composition.

[0070] An example of a blown molded article that is a multilayer structure is a blown molded article that includes an inner layer, an outer layer, and optionally one or more intermediate layers, wherein the outer layer is a layer formed from a polyamide resin composition.

[0071] Resins used for the inner layer and intermediate layer include fluorine-containing polymers having functional groups reactive to amino groups introduced into the molecular chain, polyolefin polymers, thermoplastic resin compositions, and polyamide resins other than the aliphatic polyamide resin (A) (e.g., aromatic polyamide resins such as PA6T using terephthalic acid, and aliphatic polyamide resins having a ratio of the number of methylene groups to the number of amide groups of 5.0 or less (aliphatic polyamide resins mainly composed of short-chain alkylene groups, etc.)). Here, the thermoplastic resin composition may contain a conductive filler. These fillers may be those known to those skilled in the art, depending on the location where they are to be placed and the desired properties.

[0072] In the blown molded article, the thickness of the layer formed from the polyamide resin composition is not particularly limited and can be adjusted depending on the type of polymer constituting each layer, the total number of layers in the blown molded article, the intended use, etc. When the blown molded article has a multilayer structure, the ratio of the thickness of the layer formed from the polyamide resin composition to the thickness of the blown molded article is preferably 3% or more and 90% or less. Furthermore, when the blown molded article is composed only of layers formed from the polyamide resin composition, the ratio is 100% or less.

[0073] Examples of manufacturing methods for hollow molded articles include the methods described above for molding polyamide resin compositions, and extrusion molding is preferred. In extrusion molding, a molten resin is extruded into a circular mold while being cooled to form a hollow molded article such as a tube. A multilayer hollow molded article can be manufactured by melt extrusion using an extruder corresponding to the number of layers or materials, and simultaneously laminating the layers inside or outside a die (coextrusion method). Alternatively, a multilayer hollow molded article can be manufactured by a method in which a single-layer hollow molded article or a laminated tube manufactured by the above method is manufactured in advance, and then laminated on the outside in sequence, using an adhesive as necessary, to integrate the resins (coating method).

[0074] [Uses of Molded Articles] Molded articles containing the polyamide resin composition (including hollow molded articles containing a layer formed from the polyamide resin composition; the same applies hereinafter) can be used for various purposes such as automobile parts, machine parts, industrial materials, industrial supplies, electric and electronic parts, medical products, food products, household and office supplies, building material-related parts, and furniture parts.

[0075] The molded article containing the polyamide resin composition can be used as a drug solution transport tube. Examples of the drug solution include water; alcohols and phenolic solvents such as methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, diethylene glycol, phenol, cresol, polyethylene glycol, and polypropylene glycol; ether solvents such as dimethyl ether, dipropyl ether, methyl tert-butyl ether, ethyl t-butyl ether, dioxane, and tetrahydrofuran; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, and dichloroethane. halogenated solvents such as tetrachloroethane, perchloroethane, and chlorobenzene; ketone-based solvents such as acetone, methyl ethyl ketone, diethyl ketone, and acetophenone; gasoline, kerosene, diesel gasoline, alcohol-containing gasoline, ethyl-t-butyl ether blend oxygenated gasoline, amine-containing gasoline, sour gasoline, castor oil-based brake fluid, glycol ether-based brake fluid, borate ester-based brake fluid, brake fluid for extremely cold regions, silicone oil-based brake fluid, mineral oil-based brake fluid, power steering oil, hydrogen sulfide-containing oil, windshield washer fluid, engine coolant, urea solution, pharmaceuticals, ink, paint, and the like.

[0076] The chemical solution delivery tube can cool or heat heat-generating components, such as engines, batteries, motors, and inverters, to maintain appropriate temperatures. This can extend the life of the engine and battery and maximize the vehicle's driving range. Examples of chemical solutions used for cooling or heating include those containing water and ethylene glycol. The chemical solution is preferably an aqueous solution of 30 to 70% by weight of ethylene glycol.

[0077] Specific examples of chemical liquid transport tubes include fuel tubes such as feed tubes, return tubes, evaporative tubes, fuel filler tubes, ORVR tubes, reserve tubes, and vent tubes; oil tubes, oil drilling tubes, brake tubes, windshield washer fluid tubes, engine coolant (LLC) tubes, reservoir tank tubes, urea solution transport tubes, cooler tubes for cooling water, refrigerants, etc., air conditioner refrigerant tubes, heater tubes, road heating tubes, floor heating tubes, infrastructure supply tubes, tubes for fire extinguishers and fire extinguishing equipment, tubes for medical cooling equipment, ink and paint spraying tubes, and other chemical liquid tubes.

[0078] The molded article containing the polyamide resin composition is preferably a hollow molded article that comes into contact with a coolant, and is particularly preferably a tube for transporting an automotive coolant containing ethylene glycol and / or water. Furthermore, it is particularly preferred that the hollow molded article that comes into contact with the coolant consists solely of a layer formed from the polyamide resin composition.

[0079] The thickness of the hollow molded article that comes into contact with the coolant (for example, the thickness of the layer formed from the polyamide resin composition) is designed taking into consideration the flow rate of the coolant, so that the wall thickness does not increase the amount of chemical solution permeation, is thick enough to maintain the bursting pressure of a normal hollow molded article, and maintains flexibility that allows for easy assembly of the hollow molded article and good vibration resistance during use, but is not limited thereto. Preferably, the outer diameter is 4 mm to 300 mm, the inner diameter is 3 mm to 250 mm, and the wall thickness is 0.5 mm to 25 mm.

[0080] EXAMPLES The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0081] [Production of Polyamide Resin Compositions] <Examples 1 to 10> Polyamide resin compositions were produced by pre-mixing an aliphatic polyamide resin (A), an epoxy group-containing elastomer (B), and an additive (C) according to the formulations shown in Table 1. The resulting polyamide resin composition was supplied to a twin-screw melt kneader (manufactured by Coperion Co., Ltd., model: ZSK) and melt-kneaded at a cylinder temperature of 200°C to 240°C, and the melt-kneaded polyamide resin composition was extruded in the form of strands. The resulting extrudate was directly introduced into a water tank, cooled, cut, and vacuum-dried to produce pellets of the polyamide resin composition.

[0082] Comparative Examples 1 to 4 Polyamide resin compositions and pellets of polyamide resin compositions of each comparative example were produced in the same manner as in Examples 1 to 10, except that the components shown in Table 1 were used. The composition of each component in the compositions of the examples and comparative examples is shown in Table 1. The values ​​are in mass %.

[0083] The properties and evaluation of the polyamide resin compositions obtained in the examples and comparative examples were carried out as follows. Note that the "amount of functional groups blended in 1 kg of resin composition" in the tables was calculated from the concentration of functional groups in each component and the composition ratio in the composition.

[0084] [Melt fluidity (MFR)] Using pellets of the polyamide resin compositions of Examples 1 to 10 and Comparative Examples 1 to 4, MFR (melt flow rate) was measured at a measurement temperature of 300°C and a load of 5 kg according to a method in accordance with ISO 1133. An MFR of 1.0 to 9.0 g / 10 min was determined to have excellent fluidity. In other words, an MFR of 1.0 to 9.0 g / 10 min has melt fluidity suitable for various molding methods, and is particularly applicable to extrusion molding.

[0085] [Production of Test Pieces] Test pieces were produced from the pellets of the polyamide resin compositions of Examples 1 to 10 and Comparative Examples 1 to 4 using an injection molding machine SE100D-C160S manufactured by Sumitomo Heavy Industries, Ltd. in accordance with ISO 294-1.

[0086] [Impact Resistance] Using the obtained test specimens, the Charpy impact strength (with notch) was measured according to a method in accordance with ISO 179 / 1eA.２ If the test piece had a value of 0.01 or more, it was judged to have excellent impact resistance. The results are shown in Table 1.

[0087] [Durability to deformation (tensile yield stress)] The tensile yield stress of the obtained test specimen was measured according to a method in accordance with ISO 527-1 and 2. If the tensile yield stress was 25.0 MPa or more (preferably 30.0 MPa or more), it was determined that the durability to deformation was excellent. The results are shown in Table 1.

[0088] [Toughness (nominal tensile strain at break)] The nominal tensile strain at break of the obtained test specimens was measured according to the method of ISO 527-1 and 2. If the nominal tensile strain at break was 150% or more, it was determined that the toughness was good. The results are shown in Table 1.

[0089] [Hydrolysis Resistance] Test specimens were prepared for the pellets of Examples 1, 3, 6, and 10, and Comparative Examples 2 and 3, according to the "Preparation of Test Specimens" section. The obtained test specimens were immersed in a test solution (a 50% by weight aqueous solution of ethylene glycol) prepared by mixing water and ethylene glycol in a weight ratio of 1:1, and then heated in an oven at 120°C for 1,000 hours. The nominal tensile strain at break (nominal tensile strain at break after treatment) was measured using the treated test specimens according to ISO 527-1 and 2. A specimen was judged to have excellent hydrolysis resistance if its retention rate (nominal tensile strain at break retention rate) was 50% or more relative to the untreated nominal tensile strain at break after treatment. The "untreated nominal tensile strain at break" was the value measured in the "toughness" section. The results are shown in Table 1.

[0090]

[0091] The components in Table 1 are as follows: (A) Aliphatic polyamide resin (A-1) Polyamide 12 (manufactured by UBE Corporation, polyamide 12 having an amino group concentration of 24.0 mmol / kg and a carboxyl group concentration of 37.0 mmol / kg) (A-2) Polyamide 12 (manufactured by UBE Corporation, polyamide 12 having an amino group concentration of 43.3 mmol / kg and a carboxyl group concentration of 20.2 mmol / kg) (A-3) Polyamide 12 (manufactured by UBE Corporation, polyamide 12 having an amino group concentration of 14.4 mmol / kg and a carboxyl group concentration of 68.3 mmol / kg) (B) Epoxy group-containing elastomer (B-1) Epoxy group-containing core-shell elastomer (Mitsubishi Chemical Corporation, Metablen (registered trademark) S-2200, epoxy group concentration: 167 mmol / kg). Note that (B-1) has a core-shell structure, the core is a composite elastomer of polyorganosiloxane and polyalkyl acrylate, and the shell is an epoxy group-containing polymer. (B') Elastomer not containing epoxy groups (B'-1) Epoxy group-free core-shell elastomer (Mitsubishi Chemical Corporation, Metablen (registered trademark) S-2501). Note that (B'-1) has a core-shell structure, the core is a composite elastomer of polyorganosiloxane and polyalkyl acrylate, and the shell is a methyl methacrylate polymer not containing epoxy groups. (B'-2) Acid-modified polyolefin elastomer (maleic anhydride-modified ethylene / 1-butene copolymer, manufactured by Mitsui Chemicals, Inc., Tafmer (registered trademark) MH5010) (C) Additives (C-1) Hindered phenol-based antioxidant (Irganox (registered trademark) 245 manufactured by BASF) (C-2) Phosphorus-based antioxidant (Irgafos (registered trademark) 168 manufactured by BASF) (C-3) Sulfur-based antioxidant (Sumilizer (registered trademark) TP-D manufactured by Sumitomo Chemical Co., Ltd.) (C-4) Amine-based antioxidant (OKABEST (registered trademark) CLH56 manufactured by OKA-Tec GmbH) (C-5) Carbon black (VULCAN (registered trademark) 9A32 manufactured by Cabot Corporation)

[0092] In Table 1, "x" in the deformation durability means that "yield point was not measured."

[0093] The results in Table 1 reveal the following: The polyamide resin compositions of Examples 1 to 10 were excellent in fluidity. Furthermore, the molded articles obtained using the polyamide resin compositions of Examples 1 to 10 were excellent in durability against deformation, impact resistance, and toughness. In addition, the molded articles obtained using the resin compositions of Examples 1, 3, 6, and 10 were excellent in hydrolysis resistance.

[0094] The resin composition of Comparative Example 1 had a [Z] / [X] ratio of greater than 3.40. A resin composition with low fluidity was obtained in Comparative Example 1. Furthermore, the molded article obtained using the resin composition of Comparative Example 1 had poor toughness. The resin composition of Comparative Example 2 contained an elastomer not containing epoxy groups, so the [Z] / [X] ratio was 0. A resin composition with high fluidity was obtained in Comparative Example 2. The resin composition of Comparative Example 3 had a lower blend ratio of the elastomer not containing epoxy groups compared to the resin composition of Comparative Example 2. A resin composition with high fluidity was obtained in Comparative Example 3. Furthermore, the molded article obtained using the resin composition of Comparative Example 3 had poor impact resistance. The resin composition of Comparative Example 4 contained a maleic acid-modified ethylene / 1-butene copolymer instead of the core-shell elastomer containing epoxy groups. The molded article obtained using the resin composition of Comparative Example 4 did not have a clear tensile yield point and had poor durability against deformation. Furthermore, the molded articles obtained using the resin compositions of Comparative Examples 2 and 3 had poor hydrolysis resistance.

Claims

1. A polyamide resin composition containing an aliphatic polyamide resin (A) and an epoxy group-containing elastomer (B), wherein the aliphatic polyamide resin (A) is an aliphatic polyamide resin having a ratio of the number of methylene groups to the number of amide groups of more than 5.0, and wherein the polyamide resin composition satisfies the following formulas (1) to (3), where X mmol is the amount of amino groups in the aliphatic polyamide resin (A) blended per 1 kg of the resin composition, and Z mmol is the amount of epoxy groups in the epoxy group-containing elastomer (B) blended per 1 kg of the resin composition: 1.05≦[Z] / [X]≦3.40 (1) 10.0≦[X]≦45.0 (2) 20.0≦[Z]≦80.0 (3) 2. The polyamide resin composition according to claim 1, wherein the following formula (4) is satisfied when the amount of carboxyl groups in the aliphatic polyamide resin (A) blended in 1 kg of the resin composition is Y mmol: 0.80≦[Z] / [Y]≦3.40 (4).

3. The polyamide resin composition according to claim 1, wherein the aliphatic polyamide resin (A) comprises at least one selected from the group consisting of polyundecane lactam (PA11), polylauryl lactam (PA12), polypentamethylene sebacamide (PA510), polyhexamethylene azelamide (PA69), polyhexamethylene sebacamide (PA610), polyhexamethylene dodecamide (PA612), polynonameethylene sebacamide (PA910), polynonameethylene dodecamide (PA912), polydecamethylene sebacamide (PA1010), polydecamethylene dodecamide (PA1012), and polydodecamethylene dodecamide (PA1212).

4. A polyamide resin composition according to claim 1, wherein the epoxy group-containing elastomer (B) contains, as an elastomer component, at least one selected from the group consisting of polyorganosiloxane elastomers, (meth)acrylic elastomers, styrene elastomers and polyolefin elastomers.

5. The polyamide resin composition according to claim 1, wherein the epoxy group-containing elastomer (B) has a core-shell structure, the core being at least one elastomer component selected from the group consisting of polyorganosiloxane and polyalkyl(meth)acrylate, and the shell being an epoxy group-containing polymer.

6. The polyamide resin composition according to claim 1, wherein the epoxy group-containing elastomer (B) is blended in an amount of 15.00% by mass to 30.00% by mass based on 100% by mass of the polyamide resin composition.

7. The polyamide resin composition according to claim 1, which is used for a blow molded article that comes into contact with a cooling liquid.

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

9. The molded body according to claim 8, which is cylindrical.

10. The molded article according to claim 8, which is a tank, a tube, a hose or a pipe.

11. A blow molded article comprising a layer formed from the polyamide resin composition according to any one of claims 1 to 7.

12. A blow molded article comprising a layer formed from the polyamide resin composition according to any one of claims 1 to 7 as a barrier layer.

13. A blow-molded article comprising an inner layer, an outer layer, and optionally one or more intermediate layers, wherein the outer layer is a layer formed from the polyamide resin composition according to any one of claims 1 to 7.

14. A blow molded article consisting solely of a layer formed from the polyamide resin composition according to any one of claims 1 to 7.

15. A hollow molded article that comes into contact with a coolant, which consists solely of a layer formed from the polyamide resin composition according to any one of claims 1 to 7.

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