Polyamide resin composition

Abstract

The present invention relates to a polyamide resin composition, and more specifically to a polyamide resin composition which contains a polyamide resin, a thermoplastic polyester elastomer (TPEE), an impact modifier, and a nucleating agent, and which has excellent gas barrier properties and excellent impact resistance (particularly, high low-temperature impact resistance), and which also has excellent mechanical properties such as tensile strength and heat resistance, making it extremely suitable for use as an inner liner of a gas storage container, and to a molded article (particularly, an inner liner of a gas storage container) containing the same.

Description

[Technical Field]

[0001] The present invention relates to a polyamide resin composition, and more specifically, to a polyamide resin composition which contains a polyamide resin, a thermoplastic polyester elastomer (TPEE), an impact modifier, and a nucleating agent, and which simultaneously exhibits excellent gas barrier properties and excellent impact resistance (particularly, high low-temperature impact resistance), and also has good mechanical properties such as tensile strength and heat resistance, making it extremely suitable for use as an inner liner of a gas storage container, and to a molded article (particularly, an inner liner of a gas storage container) containing the same. [Background technology]

[0002] Polyamide resins are widely used in parts for the electrical and electronic industries and the automotive industry due to their excellent heat resistance, mechanical properties, oil resistance, chemical resistance, etc., and compositions containing polyamide resins are required to have various properties depending on their specific applications. In particular, for use as inner liners for gas storage containers, polyamide resin compositions are required to have both excellent impact resistance and excellent gas barrier properties. However, conventional polyamide resin compositions have limitations in achieving both excellent impact resistance and excellent gas barrier properties. For example, the polyamide resin composition disclosed in Patent Document 1 as a material for hydrogen gas tank liners has good low-temperature impact resistance but has the disadvantage of poor gas barrier properties. On the other hand, the polyamide resin composition disclosed in Patent Document 2 as a material for gas storage tank liners has good gas barrier properties but has the disadvantage of poor low-temperature impact resistance. Therefore, there has been a need for the development of a polyamide resin composition that is suitable for use as an inner liner of a gas storage container and that simultaneously exhibits excellent gas barrier properties and excellent impact resistance (especially high low-temperature impact resistance). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 4588078 [Patent Document 2] Korean Patent No. 10-2189936 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide a polyamide resin composition which simultaneously exhibits excellent gas barrier properties and excellent impact resistance (particularly high low-temperature impact resistance) and which can be suitably used as an inner liner material for gas storage containers. [Means for solving the problem]

[0005] In order to solve the above-mentioned technical problems, the present invention provides a polyamide resin composition comprising: (1) a polyamide resin; (2) a thermoplastic polyester elastomer; (3) an impact modifier; and (4) a nucleating agent; and the polyamide resin composition has a gas permeability of 170 cm@3 at a thickness of 3 mm measured at 80°C according to ISO 15105. 3 / (m 2 Charpy notched impact strength of 20kJ / m at -40°C measured in accordance with ISO 179 2 The polyamide resin composition described above is provided. According to another aspect of the present invention, there is provided a molded article comprising the polyamide resin composition of the present invention. In one embodiment, the molded article is an inner liner of a gas storage container. [Effects of the Invention]

[0006] The polyamide resin composition of the present invention simultaneously exhibits excellent gas barrier properties and excellent impact resistance (especially high low-temperature impact resistance), which could not be achieved by conventional polyamide resin compositions, and also has excellent mechanical properties such as tensile strength and heat resistance, making it extremely suitable for use as an inner liner of a gas storage container. In particular, the polyamide resin composition of the present invention has the gas barrier properties required for an inner liner of a gas storage container (i.e., a gas permeability of 170 cm at a thickness of 3 mm measured at 80°C according to ISO 15105). 3 / (m 2 ·24h·atm) and low-temperature impact resistance (i.e., Charpy notched impact strength of 20kJ / m at -40°C measured according to ISO 179) 2 It satisfies all of the above at a high level at the same time. BEST MODE FOR CARRYING OUT THE INVENTION

[0007] The present invention will now be described in further detail. In this specification, the term "gas" is a concept that includes various gaseous substances, specific examples of which include, but are not limited to, hydrogen, methane, butane, propane, helium, nitrogen, and oxygen.

[0008] The polyamide resin composition of the present invention contains a polyamide resin. The polyamide resin can be any polyamide resin that is generally used in this field without any particular limitation. In one embodiment, the polyamide resin may be an aliphatic polyamide homopolymer, an aliphatic polyamide copolymer, or a combination thereof. More specifically, the polyamide resin may be selected from the group consisting of polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 6 / 66, polyamide 66 / 6, polyamide 66 / 612, and combinations thereof.

[0009] In one embodiment, the relative viscosity of the polyamide resin may be in the range of 2.3 to 4.0. If the relative viscosity of the polyamide resin is too low, the tensile strength, impact strength, and heat resistance of the composition may decrease. Conversely, if the relative viscosity of the polyamide resin is too high, the fluidity of the composition during molding may be insufficient, which may result in poor injection molding processability.

[0010] In one embodiment, the polyamide resin composition of the present invention may contain 30 to 95 parts by weight of the polyamide resin relative to 100 parts by weight of the total amount of the composition. If the amount of polyamide resin relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention is too low, the mechanical strength of the composition may be reduced. Conversely, if the amount of polyamide resin is too high, the impact resistance of the composition may be insufficient.

[0011] More specifically, the amount of polyamide resin relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention may be, for example, 30 parts by weight or more, 32 parts by weight or more, 35 parts by weight or more, 37 parts by weight or more, 40 parts by weight or more, 42 parts by weight or more, 45 parts by weight or more, 47 parts by weight or more, 50 parts by weight or more, 52 parts by weight or more, 55 parts by weight or more, 57 parts by weight or more, 60 parts by weight or more, 62 parts by weight or more, or 63 parts by weight or more, and may be 95 parts by weight or less, 93 parts by weight or less, 90 parts by weight or less, 88 parts by weight or less, 85 parts by weight or less, 83 parts by weight or less, or 80 parts by weight or less, but is not limited thereto.

[0012] The polyamide resin composition of the present invention also contains a thermoplastic polyester elastomer (TPEE). The thermoplastic polyester elastomer is a thermoplastic block copolymer containing a hard segment and a soft segment.

[0013] In one embodiment, the hard segments may include polymerized units of an aromatic dicarboxylic acid compound and a diol, and the soft segments may include polymerized units of a polyalkylene oxide. Specifically, the aromatic dicarboxylic acid compound may be selected from the group consisting of terephthalic acid (TPA), isophthalic acid (IPA), 1,5-naphthalenedicarboxylic acid (1,5-NDCA), 2,6-naphthalenedicarboxylic acid (2,6-NDCA), dimethyl terephthalate (DMT), dimethyl isophthalate, and combinations thereof, and preferably DMT.

[0014] The diol may be, specifically, a linear or cyclic aliphatic diol having 2 to 8 carbon atoms, more specifically, selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and combinations thereof, and preferably 1,4-butanediol. In addition, the polyalkylene oxide may specifically be selected from the group consisting of polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol (PTMEG), and combinations thereof, and may preferably be PTMEG.

[0015] In one embodiment, the thermoplastic polyester elastomer may be branched with a branching agent to increase melt tension, thereby improving strand stability and increasing productivity during TPEE production. The branching agent may be selected from the group consisting of, for example, glycerol, pentaerythritol, neopentyl glycol, and combinations thereof, preferably glycerol. The TPEE that can be used in the polyamide resin composition of the present invention may generally be produced by melt polymerization consisting of two steps of an oligomerization reaction and a polycondensation reaction, and may preferably be a branched TPEE. Branched TPEE can be produced by melt polymerization of the above components in a reactor in the presence of a suitable catalyst, such as tetra-n-butoxytitanium (TBT), in two steps: oligomerization and polycondensation. The oligomerization is carried out at 140-215°C for 3-4 hours, and the polycondensation is carried out at 210-250°C for 4-5 hours, gradually reducing the pressure from 760 torr to 0.3 torr.

[0016] Considering impact resistance and heat resistance, the soft segment content in the TPEE is preferably 5 to 75 wt %, more preferably 30 to 70 wt %, based on 100 parts by weight of the total amount of TPEE. If the soft segment content in the TPEE is too low, the hardness of the TPEE increases, making it difficult to expect improvement in impact resistance. Conversely, if the soft segment content is too high, heat resistance may decrease.

[0017] In one embodiment, the Shore hardness of the TPEE that can be used in the polyamide resin composition of the present invention may be D20 to D40.

[0018] In one embodiment, the polyamide resin composition of the present invention may contain the TPEE in an amount of 0.1 to 25 parts by weight per 100 parts by weight of the total amount of the composition. If the amount of TPEE per 100 parts by weight of the total amount of the polyamide resin composition of the present invention is too low below this level, the heat resistance of the composition may decrease, and the impact resistance or gas barrier properties may deteriorate. Conversely, if the amount of TPEE is too high above this level, both the impact resistance and gas barrier properties of the composition may decrease.

[0019] More specifically, the TPEE content relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention may be, for example, 0.1 parts by weight or more, 0.3 parts by weight or more, 0.6 parts by weight or more, 0.8 parts by weight or more, 1 part by weight or more, 1.2 parts by weight or more, 1.4 parts by weight or more, 1.5 parts by weight or more, 1.6 parts by weight or more, 1.8 parts by weight or more, or 2 parts by weight or more, and may also be 25 parts by weight or less, 23 parts by weight or less, 21 parts by weight or less, 19.9 parts by weight or less, 19.9 parts by weight or less, 19 parts by weight or less, 18 parts by weight or less, 17 parts by weight or less, 16 parts by weight or less, 15 parts by weight or less, 14 parts by weight or less, 13 parts by weight or less, 12 parts by weight or less, 11 parts by weight or less, 10 parts by weight or less, 9 parts by weight or less, or 8 parts by weight or less, but is not limited thereto.

[0020] The polyamide resin composition of the present invention also includes an impact modifier. In one embodiment, the impact modifier may be selected from the group consisting of maleic anhydride-grafted polyolefin elastomer rubber (POE-MAH), maleic anhydride-grafted ethylene propylene diene monomer rubber (EPDM-MAH), styrene-ethylene-butylene-styrene rubber (SEBS), maleic anhydride-grafted styrene-ethylene-butylene-styrene rubber (SEBS-MAH), ethylene-acrylic ester-glycidyl methacrylate random terpolymer, ethylene-acrylic acid rubber, ethylene-glycidyl methacrylate, and combinations thereof. From the viewpoints of low-temperature impact properties and heat resistance, maleic anhydride-grafted polyolefin elastomer rubber is preferably used as the impact modifier.

[0021] In one embodiment, the polyamide resin composition of the present invention may contain 3 to 40 parts by weight of the impact modifier relative to 100 parts by weight of the total amount of the composition. If the content of the impact modifier relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention is too low, the impact resistance of the composition may be reduced. Conversely, if the content of the impact modifier is too high, the gas barrier properties and heat resistance of the composition may be reduced.

[0022] More specifically, the content of the impact modifier relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention may be, for example, 3 parts by weight or more, 5 parts by weight or more, 7 parts by weight or more, 10 parts by weight or more, 11 parts by weight or more, 11.5 parts by weight or more, 12 parts by weight or more, 12.5 parts by weight or more, 13 parts by weight or more, 13.5 parts by weight or more, 14 parts by weight or more, 14.5 parts by weight or more, 15 parts by weight or more, 15.5 parts by weight or more, or 16 parts by weight or more, and may also be 40 parts by weight or less, 38 parts by weight or less, 35 parts by weight or less, 33.9 parts by weight or less, 33 parts by weight or less, 32 parts by weight or less, 31 parts by weight or less, 30 parts by weight or less, 29 parts by weight or less, 28 parts by weight or less, 27 parts by weight or less, 26 parts by weight or less, 25 parts by weight or less, or 24 parts by weight or less, but is not limited thereto.

[0023] The polyamide resin composition of the present invention also contains a nucleating agent. In one embodiment, the nucleating agent may be an inorganic nucleating agent, an organic nucleating agent, an organic / inorganic composite nucleating agent, or a combination thereof, more specifically, may be an organic / inorganic composite nucleating agent, but is not limited thereto.

[0024] More specifically, the inorganic nucleating agent may be talc, kaolin, silica, titanium dioxide, nanoclay, or a combination thereof; the organic nucleating agent may be sodium benzoate, organic phosphate, carbon fiber, polyphenylene sulfide, polycarbonate, polyphenylene oxide, a polymer having a melting point 50°C or more higher than that of polyamide 6, or a combination thereof; and the organic / inorganic composite nucleating agent may be, but is not limited to, a mixture of a polyamide component and a silicate component advantageously dispersed in a nylon phase (for example, Bruggolen P22 (polyamide 22 + alumina silicate) from Bruggemann).

[0025] In one embodiment, the polyamide resin composition of the present invention may contain 5 parts by weight or less of the nucleating agent per 100 parts by weight of the total amount of the composition. If the content of the nucleating agent per 100 parts by weight of the total amount of the polyamide resin composition of the present invention is greater than this level, the impact resistance and heat resistance of the composition may be reduced. Furthermore, even if the polyamide resin composition of the present invention contains all of the other components, if it does not contain the nucleating agent, the impact resistance of the composition may be significantly reduced.

[0026] More specifically, the content of the nucleating agent relative to 100 parts by weight of the total amount of the polyamide resin composition of the present invention may be, for example, 0.001 parts by weight or more, 0.005 parts by weight or more, 0.01 parts by weight or more, 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, or 0.05 parts by weight or more, and may also be 5 parts by weight or less, 4 parts by weight or less, 3 parts by weight or less, 2.9 parts by weight or less, 2.8 parts by weight or less, 2.5 parts by weight or less, 2.3 parts by weight or less, 2 parts by weight or less, 1.8 parts by weight or less, or 1.5 parts by weight or less, but is not limited to these.

[0027] In addition to the above components, the polyamide resin composition of the present invention may further contain one or more additives that are commonly used in polyamide resin compositions. In one embodiment, the additive is selected from a heat stabilizer, an antioxidant, a lubricant, a flame retardant, a flame retardant aid, and combinations thereof, and the amount thereof may be, but is not limited to, 0.1 to 20 parts by weight, or 1 to 10 parts by weight, relative to 100 parts by weight of the total amount of the composition.

[0028] The polyamide resin composition of the present invention has a gas permeability of 170 cm@3 at a thickness of 3 mm measured at 80°C in accordance with ISO 15105. 3 / (m 2 24h atm) and a Charpy notched impact strength of 20kJ / m at -40°C measured in accordance with ISO 179 2 At the same time, it exhibits low-temperature impact resistance equivalent to the above. More specifically, the gas permeability of the polyamide resin composition of the present invention measured at 80°C in accordance with ISO 15105 at a thickness of 3 mm is 170 cm 3 / (m 2 ·24h·atm) or less, 165cm 3 / (m 2 ·24h·atm) or less, 160cm 3 / (m 2 24h atm) or less or 155cm 3 / (m 2 Charpy notched impact strength at -40°C measured in accordance with ISO 179 may be 20kJ / m 2 More than 25kJ / m 2 More than 30kJ / m 2 or more than 35kJ / m 2 The above may be used, but is not limited to these.

[0029] The gas barrier properties and low-temperature impact resistance of the polyamide resin composition of the present invention fully satisfy the high standards required for an inner liner of a gas storage container.

[0030] The polyamide resin composition of the present invention also exhibits excellent heat resistance. According to one embodiment, the polyamide resin composition of the present invention can exhibit a tensile strength of 80% or more of the tensile strength before treatment (i.e., a tensile strength retention rate of 80% or more) even after treatment at 120°C for 3000 hours.

[0031] As described above, the polyamide resin composition of the present invention simultaneously exhibits excellent gas barrier properties and excellent impact resistance (particularly high low-temperature impact resistance), which could not be achieved with conventional polyamide resin compositions, and also has good mechanical properties such as tensile strength and heat resistance, making it extremely suitable for use as an inner liner for gas storage containers. The method for producing the polyamide resin composition of the present invention is not particularly limited and can be appropriately selected depending on the equipment used and other process factors. According to one embodiment of the present invention, polyamide resin pellets can be produced by mixing raw materials and charging them into an extruder hopper, and extruding the mixture at a melt temperature of 200 to 300°C and an RPM of 150 to 250, but is not limited thereto.

[0032] Therefore, according to another aspect of the present invention, there is provided a molded article comprising the polyamide resin composition of the present invention, and in a preferred embodiment, the molded article is an inner liner of a gas storage container. The molded article may be an extrusion molded or injection molded article of the polyamide resin composition of the present invention, and in one embodiment, the molding process may be, but is not limited to, extrusion molding, injection molding, blow molding (hollow molding), rotational molding, etc.

[0033] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples in any way. [Example]

[0034] Examples 1 to 7 and Comparative Examples 1 to 12 <Production of Polyamide Resin Composition> The components and amounts of each example and comparative example are shown in Table 1 below. Specifically, raw materials consisting of polyamide, thermoplastic polyester elastomer, impact modifier, nucleating agent, etc., as described in the component description below, were mixed in a super mixer for approximately 2 minutes, and then the mixture was fed into an extruder hopper to produce pellets. A 12-barrel 30 mm extruder (manufactured by Japan Steel Works) was used. The rotation speed was 250 rpm, and the melt temperature was set for each section based on 260°C. After the extrusion process, the composition was cooled in a cooling tank to produce pellets of the polyamide resin composition.

[0035] <Ingredients> (1) Polyamide resin: Polyamide 6 (KP Chemtech EN350AA) with a relative viscosity of 2.7

[0036] (2) Thermoplastic polyester elastomer (TPEE): TPEE with a Shore hardness of D30 was produced by the following manufacturing method and used: An oligomerization reactor was charged with 29.39 parts by weight of dimethyl terephthalate (DMT), 18.77 parts by weight of 1,4-butanediol, 51.64 parts by weight of polyoxytetramethylene glycol (PTMEG) with a molecular weight of 2,000, and 0.065 parts by weight of glycerol, and 0.025 parts by weight of tetra-n-butoxytitanium (TBT) catalyst was added. The reaction temperature was raised from 140°C to 215°C over 120 minutes, and the reaction was continued for an additional 120 minutes while maintaining at 215°C. The amount of methanol in the reaction effluent was converted into a conversion rate, and the reaction was terminated when the conversion rate reached 99% or higher. Subsequently, 0.04 parts by weight of TBT catalyst and 0.07 parts by weight of a heat stabilizer (Irganox 1010) were added, and the polycondensation reaction was carried out. The polycondensation reaction was carried out by heating from 215°C to 250°C over 120 minutes and maintaining at 250°C for an additional 120 minutes. The pressure was reduced from 760 torr to 0.3 torr for 1 hour, and then maintained at 0.3 torr or less for the remaining 3 hours, with the final pressure reduction controlled to 0.3 torr or less to produce TPEE with a Shore hardness of D 30. The inherent viscosity of the TPEE produced in this way was 1.9-2.0 dL / g when measured in a 50 / 50 phenol / tetrachloroethane (TCE) solvent.

[0037] (3) Impact modifier: Polyolefin elastomer grafted with maleic anhydride (W1A, XIAMEN COACE PLASTIC) (4-1) Nucleating agent 1: organic / inorganic composite nucleating agent (polyamide 22 + alumina silicate) (Bruggolen P22, manufactured by Bruggemann) (4-2) Nucleating agent 2: inorganic nucleating agent (talc) (KCM 2000C, KOCH) (4-3) Nucleating agent 3: Organic nucleating agent (ionomer) (Surlyn I348920) (5) Nanoclay: Layered silicate (Closite 93A) (6) Reinforcing filler: Wollastonite (Nyglos 4W) (7) Aliphatic polyamide copolymer: Novamid 2430A (PA6 / 66 copolyamide, DSM Engineering Materials) (8) Others: Heat stabilizers, antioxidants, lubricants, etc. were added to each test group in an amount of 2 parts by weight per 100 parts by weight of the total composition.

[0038] [Table 1]

[0039] <Physical property measurement and evaluation> The polyamide resin compositions produced as described above were measured and evaluated for the following physical properties, and the results are summarized in Table 2 below. (1) Low-temperature impact strength: Test specimens were prepared in accordance with ISO 179, stored in a low-temperature freezer at -40°C for 4 hours, and the Charpy notched impact strength was measured within 5 seconds after removal from the freezer. (2) Gas permeability (GTR): Gas permeability was measured using plastic test specimens according to ISO 15105. The test specimens were mounted to form a barrier between two chambers of a gas transfer cell. The test gas was sealed at high pressure in one chamber, and the permeating gas was collected and detected in the other chamber. The gas permeability test was carried out at a temperature of 80°C using hydrogen gas. The unit of permeability is cm. 3 / (m 2 ·24h·atm). (3) Evaluation of long-term heat resistance by measuring tensile strength and impact strength: After preparing test specimens according to ISO 527-2, the initial tensile strength was measured. The same test specimens were then placed in an oven set at 120°C for 3,000 hours, after which the test specimens were removed and their tensile strength was measured in the same manner. The tensile strength retention rate (%) was calculated by comparing with the initial value, and the long-term heat resistance was evaluated.

[0040] [Table 2]

[0041] As can be seen from Table 2, the polyamide resin compositions of Examples 1 to 7 had low-temperature impact strength of 20 KJ / m or more at -40°C and gas permeability of 170 cm3 / (m2·24 h·atm) or less at 80°C, making them extremely suitable as inner liners for gas storage containers. On the other hand, the compositions of Comparative Examples 1, 3 to 8, and 12 had good gas barrier properties but poor low-temperature impact resistance, making them unsuitable as materials for hydrogen gas tanks used in a temperature range including low temperatures (-40°C to 80°C). The compositions of Comparative Examples 2, 9, and 10 had good low-temperature impact resistance but poor gas barrier properties, making them unsuitable as materials for hydrogen tanks. Furthermore, the compositions of Comparative Examples 1, 2, 4 to 7, 9, 10, and 12 also had poor long-term heat resistance.

Claims

1. A polyamide resin composition, (1) a polyamide resin; (2) a thermoplastic polyester elastomer; (3) an impact modifier; and (4) a nucleating agent; Gas permeability at a thickness of 3 mm measured at 80°C according to ISO 15105 is 170 cm 3 / (m 2 24h atm) or less, and the Charpy notched impact strength at -40°C measured in accordance with ISO 179 is 20 kJ / m 2 The polyamide resin composition described above.

2. 2. The polyamide resin composition according to claim 1, wherein the polyamide resin is an aliphatic polyamide homopolymer, an aliphatic polyamide copolymer, or a combination thereof.

3. 2. The polyamide resin composition according to claim 1, wherein the thermoplastic polyester elastomer is a thermoplastic block copolymer containing a hard segment and a soft segment.

4. 4. The polyamide resin composition according to claim 3, wherein the hard segments contain polymerized units of an aromatic dicarboxylic acid compound and a diol, and the soft segments contain polymerized units of a polyalkylene oxide.

5. the aromatic dicarboxylic acid compound is selected from the group consisting of terephthalic acid (TPA), isophthalic acid (IPA), 1,5-naphthalenedicarboxylic acid (1,5-NDCA), 2,6-naphthalenedicarboxylic acid (2,6-NDCA), dimethyl terephthalate (DMT), dimethyl isophthalate, and combinations thereof; the diol is selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, and combinations thereof; 5. The polyamide resin composition according to claim 4, wherein the polyalkylene oxide is selected from the group consisting of polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol (PTMEG), and combinations thereof.

6. 2. The polyamide resin composition according to claim 1, wherein the impact modifier is selected from the group consisting of polyolefin elastomer rubber grafted with maleic anhydride (POE-MAH), ethylene propylene diene monomer rubber grafted with maleic anhydride (EPDM-MAH), styrene-ethylene-butylene-styrene rubber (SEBS), styrene-ethylene-butylene-styrene rubber grafted with maleic anhydride (SEBS-MAH), a random terpolymer of ethylene-acrylic ester-glycidyl methacrylate, ethylene-acrylic acid rubber, ethylene-glycidyl methacrylate, and combinations thereof.

7. 2. The polyamide resin composition according to claim 1, wherein the nucleating agent is an inorganic nucleating agent, an organic nucleating agent, an organic-inorganic composite nucleating agent, or a combination thereof.

8. the inorganic nucleating agent is talc, kaolin, silica, titanium dioxide, nanoclay, or a combination thereof; the organic nucleating agent is sodium benzoate, an organic phosphate, carbon fiber, polyphenylene sulfide, polycarbonate, polyphenylene oxide, a polymer having a melting point 50° C. or more higher than polyamide 6, or a combination thereof; 8. The polyamide resin composition according to claim 7, wherein the organic / inorganic composite nucleating agent is a mixture of a polyamide component and a silicate component.

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

10. 10. The molded article according to claim 9, which is an inner liner of a gas storage container.

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