JP7404774B2 - polyamide resin composition - Google Patents

Description

The present invention relates to polyamide resin compositions.

Polyamide resins are known as resins with excellent gas barrier properties, and polyamide resin compositions having gas barrier properties are in demand for various uses.

As such a polyamide resin composition, for example, a composition containing microtalc is known (see, for example, Patent Document 1). In Patent Document 1, helium permeability was confirmed in a comparative example in which only an impact-resistant material was added to a polyamide resin, and an example in which an impact-resistant material and microtalc were added to a polyamide resin, and an example in which microtalc was added was confirmed. This shows that the helium permeability is lower than that of the comparative example.

In Patent Document 1, since helium has a small atomic size, it is thought that helium is employed to confirm high gas barrier properties. However, gas permeability is not necessarily higher as the molecular size of the gas is smaller, and it is thought that various factors are involved.

Special table 2014-501818 publication

An object of the present invention is to provide a polyamide resin composition with excellent gas barrier properties.

The present invention includes, for example, the following [1] to [5].
[1] A polyamide resin composition containing a polyamide resin (A), an impact-resistant material (B), and an inorganic nucleating agent (C),
The average particle diameter of the inorganic nucleating agent (C) is 2 to 18 μm,
The polyamide resin composition was melt-kneaded in a TEX-44 twin-screw extruder with a cylinder diameter of 44 mm and L/D 35 to obtain pellets, and then the cylinder temperature was 270°C, the mold temperature was 80°C, and the average injection inside the mold was A molded piece with a thickness of 1 mm obtained by injection molding at a speed of 50 mm/sec was heated at 23°C according to JIS K7126-1.
A polyamide resin composition whose hydrogen permeability and nitrogen permeability meet the following requirements, as measured by:
Hydrogen permeability (cc/ ^m2・24h・atm): less than 55 Nitrogen permeability (cc/ ^m2・24h・atm): less than 0.35 [2] The polyamide resin (A) is polyamide 6, polyamide 66 and polyamide 6/66.
[3] The polyamide resin composition according to [1] or [2], wherein the polyamide resin (A) is polyamide 6 or a mixture of polyamide 6 and polyamide 6/66.
[4] The polyamide resin composition according to any one of [1] to [3], wherein the inorganic nucleating agent (C) is talc.
[5] In 100% by mass of the polyamide resin composition, 78 to 94% by mass of polyamide resin (A), 5 to 20% by mass of impact material (B), and 0.01 to 0.5% by mass of inorganic nucleating agent (C). % of the polyamide resin composition according to any one of [1] to [4].

The polyamide resin composition of the present invention has excellent gas barrier properties.

The polyamide resin composition of the present invention is a polyamide resin composition containing a polyamide resin (A), an impact-resistant material (B), and an inorganic nucleating agent (C),
The average particle diameter of the inorganic nucleating agent (C) is 2 to 18 μm,
The polyamide resin composition was melt-kneaded in a TEX-44 twin-screw extruder with a cylinder diameter of 44 mm and L/D 35 to obtain pellets, and then the cylinder temperature was 270°C, the mold temperature was 80°C, and the average injection inside the mold was A molded piece with a thickness of 1 mm obtained by injection molding at a speed of 50 mm/sec was heated at 23°C according to JIS K7126-1.
The hydrogen permeability and nitrogen permeability measured by the above meet the following requirements.
Hydrogen permeability (cc/ ^m2・24h・atm): Less than 55 Nitrogen permeability (cc/ ^m2・24h・atm): Less than 0.35 <Polyamide resin (A)>
The polyamide resin composition contains polyamide resin (A). Examples of the polyamide resin (A) include aliphatic homopolyamide (A-1), aliphatic copolyamide (A-2), aromatic homopolyamide (A-3), and aromatic copolyamide (A-4). Can be mentioned. These may be used alone or in combination of two or more.

(Aliphatic homopolyamide (A-1))
Aliphatic homopolyamide (A-1) is a polyamide resin consisting of one type of structural unit derived from an aliphatic monomer. The aliphatic homopolyamide (A-1) may consist of at least one of one type of lactam and an aminocarboxylic acid that is a hydrolyzate of the lactam, and one type of diamine and one type of dicarboxylic acid. It may consist of a combination of. Here, the combination of diamine and dicarboxylic acid is considered to be one type of monomer.

Examples of the lactam include ε-caprolactam, enantholactam, undecanelactam, dodecanelactam, α-pyrrolidone, α-piperidone, and the like. Among these, from the viewpoint of polymerization productivity, one selected from the group consisting of ε-caprolactam, undecanelactam, and dodecanelactam is preferred.
Further, examples of aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

Examples of diamines include ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, peptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, and tetradecanediamine. , pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,8-octanediamine, 2,2,4/2,4,4-trimethylhexamethylenediamine, etc. aliphatic diamine; 1,3-/1,4-cyclohexyldiamine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(3-methyl-4-aminocyclohexyl)methane, (3 -Methyl-4-aminocyclohexyl)propane, 1,3-/1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3 , 3-trimethylcyclohexanemethylamine, bis(aminopropyl)piperazine, bis(aminoethyl)piperazine, and norbornane dimethylenediamine.

Dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, and pentadecane. Aliphatic dicarboxylic acids such as dionic acid, hexadecanedionic acid, octadecanedioic acid, and eicosanedioic acid; 1,3-/1,4-cyclohexanedicarboxylic acid, dicyclohexanemethane-4,4'-dicarboxylic acid, norbornanedicarboxylic acid Examples include alicyclic dicarboxylic acids such as.

Specifically, the aliphatic homopolyamide (A-1) includes polycaprolactam (polyamide 6), polyenanthlactam (polyamide 7), polyundecane lactam (polyamide 11), polylauryllactam (polyamide 12), and polyhexamethylene azide. Pamide (Polyamide 66), Polytetramethylene Dodecamide (Polyamide 412), Polypentamethylene Azeramide (Polyamide 59), Polypentamethylene Sebaamide (Polyamide 510), Polypentamethylene Dodecamide (Polyamide 512), Polyhexane methylene azeramide (polyamide 69), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polynonamethylene adipamide (polyamide 96), polynonamethylene azeramide (polyamide 99), Polynonamethylene sebaamide (Polyamide 910), Polynonamethylene dodecamide (Polyamide 912), Polydecamethylene adipamide (Polyamide 106), Polydecamethylene azeramide (Polyamide 109), Polydecamethylene decamide (Polyamide 1010) ), polydodecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene azeramide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), polydodecamethylene dodecamide ( Examples include polyamide 1212) and polyamide 122. These aliphatic homopolyamides (A-1) can be used alone or as a mixture of two or more.

(Aliphatic copolymer polyamide (A-2))
The aliphatic copolymerized polyamide (A-2) is a polyamide resin composed of two or more types of structural units derived from aliphatic monomers. The aliphatic copolymerized polyamide (A-2) is a copolymer of two or more selected from the group consisting of a combination of diamine and dicarboxylic acid, lactam, and aminocarboxylic acid. Here, the combination of diamine and dicarboxylic acid is considered to be one type of monomer.

Examples of the diamine include the same diamines as those exemplified as raw materials for aliphatic homopolyamide. Can be mentioned.

As the dicarboxylic acid, the same ones as those exemplified as raw materials for the aliphatic homopolyamide can be mentioned.

Examples of the lactam include the same lactams as those exemplified as raw materials for aliphatic homopolyamide.
Moreover, as the aminocarboxylic acid, the same ones as those exemplified as the raw material for the aliphatic homopolyamide can be mentioned.
These diamines, dicarboxylic acids, lactams, and aminocarboxylic acids may be used alone or in combination of two or more.

Specifically, the aliphatic copolymerized polyamide (A-2) includes caprolactam/hexamethylene diamino adipic acid copolymer (polyamide 6/66), caprolactam/hexamethylene diamino azelaic acid copolymer (polyamide 6/69), Caprolactam/hexamethylene diamino undecane dicarboxylic acid copolymer (polyamide 6/610), caprolactam/hexamethylene diamino undecane dicarboxylic acid copolymer (polyamide 6/611), caprolactam/hexamethylene diamino dodecane dicarboxylic acid copolymer (polyamide 6/610) 612), caprolactam/aminoundecanoic acid copolymer (polyamide 6/11), caprolactam/lauryllactam copolymer (polyamide 6/12), caprolactam/hexamethylene diamino adipic acid/lauryllactam copolymer (polyamide 6/66) /12), caprolactam/hexamethylene diamino adipic acid/hexamethylene diamino sebacic acid copolymer (polyamide 6/66/610), caprolactam/hexamethylene diamino adipic acid/hexamethylene diamino dodecane dicarboxylic acid copolymer (polyamide 6/ Examples include aliphatic copolymer polyamides such as 66/612). These aliphatic copolymer polyamides (A-2) can be used alone or as a mixture of two or more.

(Aromatic homopolyamide (A-3))
Aromatic homopolyamide is an aromatic polyamide resin consisting of one type of structural unit derived from an aromatic monomer component, for example, an aliphatic dicarboxylic acid and an aromatic diamine, an aromatic dicarboxylic acid and an aliphatic diamine, or an aromatic homopolyamide. It is a polyamide resin obtained by polycondensation of dicarboxylic acid and aromatic diamine as raw materials. Here, the combination of diamine and dicarboxylic acid is considered to be one type of monomer.

Examples of the raw material aliphatic diamine and aliphatic dicarboxylic acid include those similar to those for the aliphatic homopolyamide resin described above, and also include those exemplified as the alicyclic diamine and alicyclic dicarboxylic acid.
Examples of aromatic diamines include metaxylylene diamine and paraxylylene diamine, and examples of aromatic dicarboxylic acids include naphthalene dicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid.

Specific examples of the aromatic homopolyamide (A-3) include polynonane methylene terephthalamide (polyamide 9T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), and polyxylylene. Examples include adipamide (polyamide MXD6). These aromatic homopolyamides (A-3) can be used alone or as a mixture of two or more.

(Aromatic copolymer polyamide (A-4))
Aromatic copolymerized polyamide resin is a polyamide resin that contains at least one type of structural unit derived from an aromatic monomer component and is composed of two or more types of structural units, such as aliphatic dicarboxylic acid, aromatic diamine, aromatic Among the aromatic polyamide resins obtained by polycondensation of dicarboxylic acid and aliphatic diamine or aromatic diamine and aromatic dicarboxylic acid as raw materials, it is a polyamide resin consisting of two or more types of structural units. Here, the combination of diamine and dicarboxylic acid is considered to be one type of monomer.

Examples of the raw material aliphatic diamine and aliphatic dicarboxylic acid include those similar to those exemplified as the raw material for the aliphatic homopolyamide resin, and also include those exemplified as the alicyclic diamine and alicyclic dicarboxylic acid. It will be done.
Examples of aromatic diamines include metaxylylene diamine and paraxylylene diamine, and examples of aromatic dicarboxylic acids include naphthalene dicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid.
In addition, the aromatic copolyamide resin may contain structural units derived from lactams and aminocarboxylic acids, and the lactams and aminocarboxylic acids are the same as those exemplified as raw materials for the aliphatic homopolyamide resins. Things can be mentioned.
These diamines, dicarboxylic acids, lactams, and aminocarboxylic acids may be used alone or in combination of two or more.

Specific examples of the aromatic copolymerized polyamide (A-4) include polyhexamethylene adipamide/polyhexamethylene terephthalamide copolymer (polyamide 66/6T), polyhexamethylene terephthalamide/polycaproamide copolymer (polyamide 6T/6), polyhexamethylene adipamide/polyhexamethylene isophthalamide copolymer (polyamide 66/6I), polyhexamethylene isophthalamide/polycaproamide copolymer (polyamide 6I/6), polydodecamide/polyhexamethylene terephthalamide copolymer (Polyamide 12/6T), Polyhexamethylene adipamide/Polyhexamethylene terephthalamide/Polyhexamethylene isophthalamide copolymer (Polyamide 66/6T/6I), Polyhexamethylene adipamide/Polycaproamide/Polyhexamethylene isophthalamide amide copolymer (polyamide 66/6/6I), polyhexamethylene terephthalamide/polyhexamethylene isophthalamide copolymer (polyamide 6T/6I), polyhexamethylene terephthalamide/poly(2-methylpentamethylene terephthalamide) copolymer (polyamide 6T) /M5T) and mixtures or copolymer resins thereof. These aromatic copolymer polyamides (A-4) can be used alone or as a mixture of two or more.

(Production of polyamide resin)
Polyamide resin manufacturing equipment includes batch reaction vessels, single-vessel or multi-vessel continuous reaction apparatuses, tubular continuous reaction apparatuses, kneading reaction extruders such as single-screw kneading extruders, twin-screw kneading extruders, etc. Known polyamide manufacturing equipment can be mentioned. As the polymerization method, known methods such as melt polymerization, solution polymerization, and solid phase polymerization can be used, and polymerization can be carried out by repeating normal pressure, reduced pressure, and pressurization operations. These polymerization methods can be used alone or in combination as appropriate.

Among the polyamide resins, from the viewpoint of crystallinity of the polyamide resin, at least one selected from the group consisting of polyamide 6, polyamide 66 and polyamide 6/66 is preferable; At least one of polyamide 6 and polyamide 6/66 is more preferred, and polyamide 6 and a mixture of polyamide 6 and polyamide 6/66 are even more preferred.

Although preferred polyamide resins have been illustrated above, polyamide resins are not necessarily limited to the preferred examples. The present invention is based on the discovery that gas permeability varies depending on the average particle size of talc, regardless of the type of polyamide resin.

(Relative viscosity of polyamide resin)
The polyamide resin (A) is based on JIS K-6920, and has a relative viscosity of 2.7 or more, measured by dissolving 1 g of the polyamide resin in 100 ml of 96% concentrated sulfuric acid at 25°C, and 5. It is preferably 0 or less. It is thought that within the above range, crystallinity becomes high and gas permeability is improved.

When the polyamide resin (A) contains two or more types of polyamide resins with different relative viscosities, the relative viscosity of the polyamide resin (A) is preferably measured as described above, but the relative viscosity of each polyamide resin and its When the mixing ratio is known, the relative viscosity of the polyamide resin (A) may be the average value calculated by summing the values obtained by multiplying each relative viscosity by the mixing ratio.

The terminal amino group concentration of the polyamide resin (A) is 30 μmol/g or more as the terminal amino group concentration determined by neutralization titration after dissolving in a mixed solvent of phenol and methanol, and is in the range of 30 μmol/g or more and 110 μmol/g or less. is preferable, and the range of 30 μmol/g or more and 70 μmol/g or less is more preferable. Within the above range, molding processability of a molded article using the polyamide resin composition is good.

When the polyamide resin (A) contains two or more types of polyamide resins having different terminal amino group concentrations, it is preferable that the terminal amino group concentration in the polyamide resin (A) is measured by the neutralization method described above, but each If the terminal amino group concentration and the mixing ratio of the polyamide resin (A) are known, the average value calculated by summing the values obtained by multiplying each terminal amino group concentration by the mixing ratio is calculated as the average value of the polyamide resin (A). It may also be the terminal amino group concentration.

The polyamide resin (A) is preferably contained in an amount of 78 to 94% by mass, more preferably 80 to 92% by mass, based on 100% by mass of the polyamide resin composition. When the content ratio of the polyamide resin (A) is within the above range, the molding processability of the molded product using the polyamide resin composition is good.

<Shock-resistant material (B)>
The polyamide resin composition includes an impact resistant material (B). Examples of the impact-resistant material (B) include rubber-like polymers. The impact-resistant material preferably has a flexural modulus of 500 MPa or less as measured in accordance with ASTM D-790.

Specifically, the impact-resistant material (B) includes (ethylene and/or propylene)/α-olefin copolymer, (ethylene and/or propylene)/(α,β-unsaturated carboxylic acid and/or α, Examples include copolymers based on β-unsaturated carboxylic acid esters. These can be used alone or in combination of two or more. The impact-resistant material (B) is preferably an ethylene/α-olefin copolymer.

The (ethylene and/or propylene)/α-olefin copolymer is a copolymer of ethylene and/or propylene and an α-olefin having 3 or more or 4 or more carbon atoms.
Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1 -tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl -1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3 -ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene and the like. These may be used alone or in combination of two or more.

Further, the copolymer may be one obtained by copolymerizing a polyene such as a non-conjugated diene. Examples of non-conjugated dienes include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-octadiene, 1,5-octadiene, 1,6-octadiene, 1,7-octadiene, 2- Methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4,8-dimethyl-1, 4,8-decatriene (DMDT), dicyclopentadiene, cyclohexadiene, cyclooctadiene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropylidene-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,5-norbornadiene, etc. Can be mentioned. These may be used alone or in combination of two or more.

(ethylene and/or propylene)/(α,β-unsaturated carboxylic acid and/or α,β-unsaturated carboxylic acid ester) copolymer is ethylene and/or propylene and α,β-unsaturated carboxylic acid. and/or a copolymer of α,β-unsaturated carboxylic acid ester monomer. Examples of the α,β-unsaturated carboxylic acid monomer include acrylic acid and methacrylic acid. Examples of α,β-unsaturated carboxylic acid ester monomers include methyl ester, ethyl ester, propyl ester, butyl ester, pentyl ester, hexyl ester, heptyl ester, octyl ester, and nonyl ester of these α,β-unsaturated carboxylic acids. Examples include ester and decyl ester. These may be used alone or in combination of two or more.

In addition, (ethylene and/or propylene)/α-olefin copolymer and (ethylene and/or propylene)/(α,β-unsaturated carboxylic acid and/or α, The β-unsaturated carboxylic acid ester) copolymer is preferably a polymer modified with a carboxylic acid and/or a derivative thereof, and a polymer modified with an acid such as an unsaturated carboxylic acid or its acid anhydride. It is more preferable that By modifying with such a component, the molecule contains a functional group that has an affinity for the polyamide resin (A).

Examples of the functional group having affinity for the polyamide resin (A) include a carboxy group, an acid anhydride group, a carboxylic acid ester group, a carboxylic acid metal salt, a carboxylic acid imide group, a carboxylic acid amide group, an epoxy group, etc. It will be done.

Examples of compounds containing these functional groups, ie carboxylic acids and their derivatives, include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, mesaconic acid, citraconic acid, glutaconic acid, cis-4- Cyclohexene-1,2-dicarboxylic acid, endobicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid and metal salts of these carboxylic acids, monomethyl maleate, monomethyl itaconate, methyl acrylate, Ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, 2-ethylhexyl methacrylate, hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, maleic anhydride , itaconic anhydride, citraconic anhydride, endobicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, Examples include acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, glycidyl citraconate, and the like. These can be used alone or in combination of two or more. Among these, maleic anhydride is preferred.

The content of acid anhydride groups in the impact-resistant material (B) is more than 25 μmol/g and less than 100 μmol/g, preferably 35 μmol/g or more and less than 95 μmol/g, more preferably 40 μmol/g or more and less than 90 μmol/g. When the content exceeds 25 μmol/g, a composition with a high melt viscosity can be obtained, and a target wall thickness can be obtained in blow molding. Moreover, when the content is less than 100 μmol/g, the melt viscosity is not too high, and the load on the extruder can be suppressed to allow good molding. The content of acid anhydride groups in the impact-resistant material (B) can be determined by neutralization titration with a 0.1 N KOH ethanol solution using a sample solution prepared using toluene and ethanol and using phenolphthalein as an indicator. It is measured in

When using two or more types of impact resistant materials with different contents of acid anhydride groups as the impact resistant material (B), the content of acid anhydride groups in the impact resistant material (B) is determined by using toluene and ethanol. It is preferable to measure by neutralization titration with a 0.1 N KOH ethanol solution using the prepared sample solution and using phenolphthalein as an indicator. If the mixing ratio is known, the average value calculated by summing the content of each acid anhydride group multiplied by the mixing ratio is used as the acid anhydride content of the impact material (B). good.

The impact-resistant material (B) preferably has an MFR of 0.1 g/10 minutes or more and 10.0 g/10 minutes or less when measured at a temperature of 230° C. and a load of 2160 g in accordance with ASTM D1238. When the MFR is 0.1 g/10 minutes or more, the melt viscosity of the polyamide resin composition will not become too high, and for example, the shape of the parison will be prevented from becoming unstable during blow molding in extrusion molding, and the thickness of the molded object will be reduced. tends to be more uniform. Moreover, when the MFR is 10.0 g/10 minutes or less, the drawdown of the parison does not become too large and good blow moldability tends to be obtained.

The impact-resistant material (B) is preferably contained in an amount of 5 to 20% by weight, more preferably 6 to 19% by weight, and even more preferably 7 to 18% by weight based on 100% by weight of the polyamide resin composition. preferable. When the content ratio of the impact-resistant material (B) is within the above range, gas barrier properties are good.

<Inorganic nucleating agent (C)>
The polyamide resin composition contains an inorganic nucleating agent (C). The inorganic nucleating agent (C) has an average particle diameter of 2 to 18 μm, preferably 5 to 16 μm, and more preferably 10 to 14 μm. When the average particle diameter is within the above range, gas barrier properties are excellent.
The average particle size of the inorganic nucleating agent (C) is the average particle size determined by a particle size distribution measurement method using a laser diffraction/scattering method. As a measuring device, a laser diffraction particle size distribution measuring device SALD-7000 manufactured by Shimadzu Corporation may be used. When using a commercial product as the inorganic nucleating agent, the catalog value of the commercial product is used as the average particle diameter of the inorganic nucleating agent.

Examples of inorganic nucleating agents (C) include talc, mica, synthetic mica, glass flakes, non-swellable mica, fullerene, carbon nanotubes, carbon black, graphite, metal foil, ceramic beads, clay, sericite, zeolite, and bentonite. , aluminum hydroxide, dolomite, kaolin, silica, finely divided silicic acid, feldspar powder, potassium titanate, shirasu balloon, calcium carbonate, magnesium carbonate, barium sulfate, calcium oxide, aluminum oxide, titanium oxide, magnesium oxide, aluminum silicate, Silicon oxide, magnesium hydroxide, gypsum, novaculite, dawsonite, clay, glass fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, silicon whisker, wollastenite, sepiolite, Examples include slag fiber, zonolite, elestadite, gypsum fiber, silica fiber, silica/alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, and boron fiber.
Among these, talc is preferred from the viewpoint of suppressing nitrogen and hydrogen gas permeability.

The inorganic nucleating agent (C) is preferably contained in an amount of 0.01 to 0.5% by mass, more preferably 0.01 to 0.4% by mass, and 0.01 to 0.5% by mass, more preferably 0.01 to 0.4% by mass, based on 100% by mass of the polyamide resin composition. More preferably, it is contained in an amount of 0.02 to 0.3% by mass. When the content of the inorganic nucleating agent (C) is within the above range, gas barrier properties are good.

[Optional component (D)]
Depending on the purpose, the polyamide resin composition may contain dyes, pigments, fibrous reinforcements, particulate reinforcements, plasticizers, antioxidants, heat resistant agents, foaming agents, weathering agents, crystal nucleating agents (components) as optional components. (C)), crystallization accelerators, mold release agents, lubricants, antistatic agents, flame retardants, flame retardant aids, colorants, and other functional imparting agents may be appropriately contained. In order to improve the effects of the present invention, the polyamide resin composition preferably contains an antioxidant.
The optional additive (D) is contained in an amount of preferably 0.01 to 1% by weight, more preferably 0.05 to 0.5% by weight based on 100% by weight of the polyamide resin composition.

[Method for manufacturing polyamide resin composition]
The method for producing the polyamide resin composition is not particularly limited, and for example, the following method can be applied.
For mixing the polyamide resin (A), impact-resistant material (B), inorganic nucleating agent (C), and other optional components, a single-screw or twin-screw extruder, Banbury mixer, kneader, mixing roll, etc. A commonly known melt kneader is usually used. For example, using a twin-screw extruder, all the raw materials are blended and then melt-kneaded, some of the raw materials are blended and then melt-kneaded, and the remaining raw materials are further blended and melt-kneaded, or some of the raw materials are blended and then melt-kneaded. Any method may be used, such as a method in which after blending the raw materials, the remaining raw materials are mixed using a side feeder during melt-kneading.

[Hydrogen permeability and nitrogen permeability]
After melt-kneading the polyamide resin composition in a TEX-44 twin-screw extruder with a cylinder diameter of 44 mm and L/D 35 to obtain pellets, the cylinder temperature was 270°C, the mold temperature was 80°C, and the average injection speed in the mold was The hydrogen permeability and nitrogen permeability of a molded piece having a thickness of 1 mm obtained by injection molding at 50 mm/sec and measured at 23° C. according to JIS K7126-1 are as follows.
Hydrogen permeability (cc/m ² ·24 h ·atm) is less than 55.
The nitrogen permeability (cc/m ² ·24 h ·atm) is less than 0.35.
Note that the specific measurement conditions for hydrogen permeability and nitrogen permeability are the conditions described in Examples.
Since the hydrogen permeability and nitrogen permeability are within the above range, the polyamide resin composition of the present invention has excellent gas barrier properties when formed into a molded article.

[Applications of polyamide resin composition]
The polyamide resin composition can be suitably used for producing blow molded products by blow molding. Furthermore, it can be suitably used for manufacturing extrusion molded products by extrusion molding.
There are no particular restrictions on the method for producing a blow molded product from a polyamide resin by blow molding, and any known method can be used. Generally, blow molding may be performed after forming a parison using a normal blow molding machine. Preferably, the resin temperature during parison formation is 10°C to 70°C higher than the melting point of the polyamide resin composition.

The method for producing an extrusion molded product from a polyamide resin by extrusion molding is not particularly limited, and any known method can be used.
It is also possible to obtain a multilayered structure by coextruding it with a polyolefin such as polyethylene or another thermoplastic resin and then blow molding it. In that case, it is also possible to provide an adhesive layer between the polyamide resin composition layer and another thermoplastic resin layer such as polyolefin. In the case of a multilayer structure, the polyamide resin composition of the present invention can be used for both the outer layer and the inner layer.

Blow molded products by blow molding and extrusion molded products by extrusion molding include, but are not particularly limited to, spoilers, air intake ducts, intake manifolds, resonators, fuel tanks, gas tanks, hydraulic oil tanks, fuel filler tubes, fuel delivery pipes, and others. Automotive parts such as various hoses, tubes and tanks, mechanical parts such as power tool housings and pipes, electrical and electronic parts such as tanks, tubes, hoses and films, household and office supplies, building material related parts, and furniture. Preferred examples include various uses such as parts.
Since polyamide resin compositions have excellent gas barrier properties, they are suitably used for molded objects that come into contact with gas, such as tanks, tubes, hoses, and films that come into contact with gas.
The type of gas is not particularly limited, but includes hydrogen, nitrogen, oxygen, helium, methane, butane, propane, etc. Gases with low polarity are preferred, and hydrogen and nitrogen are more preferred.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Evaluation method]
Hydrogen permeability and nitrogen permeability In accordance with JIS K7126-1, a hydrogen permeation test and a nitrogen permeation test were conducted at 23° C. and 0% RH using a gas chromatography method using a 1 mm thick test piece. The measuring device used was GTR-21A-B, serial number GTR-1400120 (manufactured by GTR Tech). A test piece was manufactured using each component listed in Table 1 under the following melt-kneading conditions and the following injection molding conditions.

Polyamide resin: Polyamide 6 (UBE Nylon 1013B manufactured by Ube Industries, Ltd.)

Impact-resistant material: maleic anhydride-modified ethylene-butene copolymer (manufactured by Mitsui Chemicals, Inc., Tafmer MH5020)

Talc 14.20 μm: (KHP-400 manufactured by Hayashi Kasei Co., Ltd., average particle size 14.20 μm)
Talc 13μm: (manufactured by Ube Materials: LS-408, average particle size 13μm)
Talc 0.6 μm: (NANO ACE D-600 manufactured by Nippon Talc Co., Ltd., average particle size 0.6 μm)
Talc 19.5 μm: (KHP-400B manufactured by Hayashi Kasei Co., Ltd., average particle size 19.5 μm)
The average particle diameter of talc is a catalog value.

[Examples 1-2, Comparative Examples 1-3]
The components listed in Table 1 were blended in the proportions listed in Table 1, and melt-kneaded under the following melt-kneading conditions to produce desired polyamide resin composition pellets.
Next, test pieces with a thickness of 1 mm were manufactured from the obtained pellets under the following injection molding conditions, and various physical properties were measured. The results are shown in Table 1.
In addition, the unit of the composition in Table 1 is mass %, and the whole polyamide resin composition is taken as 100 mass %.

<Melt kneading conditions>
Uses TEX-44 twin screw extruder Cylinder diameter: 44mm
L/D: 35
Screw rotation speed: 120rpm

<Injection molding conditions>
Cylinder temperature: 270℃
Mold temperature: 80℃
Average injection speed in the mold: 50mm/sec
Cooling time: 5 seconds

From Table 1, when comparing Examples 1 and 2 and Comparative Example 1, it can be seen that when the average particle diameter of the inorganic nucleating agent is smaller than the range of the present application, the nitrogen permeability increases by about 10%. Comparing Examples 1 and 2 and Comparative Example 2, it is found that when the average particle diameter of the inorganic nucleating agent is larger than the range of the present application, hydrogen permeability increases by about 10% and nitrogen permeability increases by about 10%. Recognize. Comparing Examples 1 and 2 with Comparative Example 3, it can be seen that the hydrogen permeability is significantly increased when an inorganic nucleating agent is not included.

Claims (4)

A polyamide resin composition containing a polyamide resin (A), an impact-resistant material (B), and an inorganic nucleating agent (C),
The average particle diameter of the inorganic nucleating agent (C) is 2 to 18 μm,
the inorganic nucleating agent (C) is talc;
The polyamide resin composition was melt-kneaded in a TEX-44 twin-screw extruder with a cylinder diameter of 44 mm and L/D 35 to obtain pellets, and then the cylinder temperature was 270°C, the mold temperature was 80°C, and the average injection inside the mold was A molded piece with a thickness of 1 mm obtained by injection molding at a speed of 50 mm/sec was heated at 23°C according to JIS K7126-1.
A polyamide resin composition whose hydrogen permeability and nitrogen permeability meet the following requirements, as measured by:
Hydrogen permeability (cc/ ^m2・24h・atm): Less than 55 Nitrogen permeability (cc/ ^m2・24h・atm): Less than 0.35 The polyamide resin composition according to claim 1, wherein the polyamide resin (A) is at least one selected from the group consisting of polyamide 6, polyamide 66, and polyamide 6/66. The polyamide resin composition according to claim 1 or 2, wherein the polyamide resin (A) is polyamide 6 or a mixture of polyamide 6 and polyamide 6/66. Contains 78 to 94 mass% of polyamide resin (A), 5 to 20 mass% of impact material (B), and 0.01 to 0.5 mass% of inorganic nucleating agent (C) in 100 mass% of polyamide resin composition. The polyamide resin composition according to any one of claims 1 to 3 .