Polyamide resin composition

Abstract

To provide a polyamide resin composition which has good calcium chloride resistance, has a low extraction amount by a Soxhlet extraction method in the case where water is used as a solvent and methanol is used as a solvent, has insulation properties, has low water absorption, and has excellent mechanical characteristics at the time of water absorption.SOLUTION: A polyamide resin composition contains, in 100 mass% of the polyamide resin composition, 60-95 mass% of a polyamide resin (A), and 5-40 mass% of a novolak type phenol resin (B), wherein the polyamide resin (A) has relative viscosity measured at 25°C according to JIS K 6920-2 of 1.9 or more and 5.0 or less, the novolak type phenol resin (B) has a softening point temperature of 130°C or lower, and an extraction content when the polyamide resin composition is extracted by a Soxhlet extraction method using water as a solvent for 6 hours is 1.5 mass% or less with respect to 100 mass% of the polyamide resin composition using in extraction.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In the automotive industry, in order to reduce fuel consumption, there is a tendency to replace conventional metal parts with resin parts for the purpose of vehicle body weight reduction, rust prevention, sound insulation effect, etc. Among them, nylon 6 and nylon 66 have considerable usage records as automotive part materials because of their high heat resistance and rigidity. However, these polyamides have the drawback that they are easily cracked when exposed to road freezing preventives using metal halide salts such as calcium chloride, magnesium chloride, zinc chloride, and rock salt. Several methods have been proposed to improve this drawback.

[0003] Patent Document 1 discloses an automotive under-hood part made of a polyamide resin having road freezing preventive agent resistance and low water absorption, which is composed of a polyamide resin composition containing 90 to 60% by weight of polyamide, 5 to 30% by weight of a phenolic compound, and 5 to 25% by weight of an ethylene-based elastomer. As this phenolic compound, a novolak-type phenolic resin is used.

[0004] Polyamide resin compositions containing a polyamide resin and a novolak-type phenolic resin are also disclosed in Patent Documents 2 to 4. Patent Document 2 describes that a polyamide resin composition containing a polyamide resin and a high molecular weight novolak-type phenolic resin can greatly improve the glass transition temperature of the polyamide resin composition and has excellent mechanical strength not only in the dry state but also in the water-absorbed state. Patent Document 3 describes that a polyamide resin composition obtained by adding 1 to 15% by weight of a novolak-type phenolic resin to a polyamide resin can increase the melt flow index. Patent Document 4 describes a polyamide resin composition containing a low melt viscosity polyamide resin, a low molecular weight novolac-type phenolic resin, and a filler, which exhibits excellent melt flowability while containing a high amount of filler. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 188456 / 1983 [Patent Document 2] Japanese Patent Publication No. 2016-113603 [Patent Document 3] Special Publication No. 2011-500875 [Patent Document 4] Japanese Patent Publication No. 2003-246934 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] However, in Patent Document 1, because it contains a specific amount of ethylene-based elastomer, the mechanical properties and heat resistance of the polyamide resin composition sometimes deteriorated. In Patent Document 2, because the novolac-type phenolic resin has a high molecular weight, the fluidity of the polyamide resin composition decreased, and sufficient moldability could not be obtained. In Patent Document 3, because the content of the novolac-type phenolic resin was small, the water absorption of the polyamide resin could not be sufficiently suppressed. In Patent Document 4, because a low melt viscosity polyamide resin and a low molecular weight novolac-type phenolic resin were combined, the molecular weight was low and the amount of inorganic filler increased, which sometimes reduced impact resistance. The present invention aims to provide a polyamide resin composition that exhibits good calcium chloride resistance, low extraction yield by Soxhlet extraction using water and methanol as solvents, insulating properties, low water absorption, and excellent mechanical properties when water is absorbed. [Means for solving the problem]

[0007] The present invention includes, for example, the following [1] to [8]. [1] A polyamide resin composition comprising 60 to 95% by mass of polyamide resin (A) and 5 to 40% by mass of novolac-type phenolic resin (B) in 100% by mass of the polyamide resin composition, The polyamide resin (A) has a relative viscosity of 1.9 or more and 5.0 or less, as measured at 25°C in accordance with JIS K6920-2. The novolac-type phenolic resin (B) has a softening point temperature of 130°C or lower. A polyamide resin composition in which, when the polyamide resin composition is extracted for 6 hours by Soxhlet extraction using water as the solvent, the extracted amount is 1.5% by mass or less relative to 100% by mass of the polyamide resin composition used for extraction. [2] A polyamide resin composition of [1] in which the novolac-type phenolic resin (B) is a novolac-type phenolic resin represented by the following formula (1). [ka] (In equation (1) above, n is between 1 and 200.) [3] A polyamide resin composition according to [1] or [2], wherein the polyamide resin (A) comprises at least one selected from the group consisting of aliphatic homopolyamide resin (A-1) and aliphatic copolymer polyamide resin (A-2). [4] The novolac-type phenolic resin (B) is a polyamide resin composition of any of [1] to [3]3 having a softening point temperature of 110 to 130°C. [5] A polyamide resin composition comprising, in addition to the polyamide resin (A), a novolac-type phenolic resin (B) as the main component, any of the polyamide resin compositions [1] to [4]. [6] A polyamide resin composition that is substantially free of ethylene-based elastomers, as described in [1] to [5]. A molded article made of any of the polyamide resin compositions [7][1] to [6]. [8] A molded part of an automobile [7]. [Effects of the Invention]

[0008] The polyamide resin composition of the present invention exhibits low extraction yield by Soxhlet extraction using water and methanol as solvents, good resistance to calcium chloride, insulating properties, low water absorption, and excellent mechanical properties when water is absorbed. [Modes for carrying out the invention]

[0009] The present invention relates to a polyamide resin composition comprising 60 to 95% by mass of polyamide resin (A) and 5 to 40% by mass of novolac-type phenolic resin (B) in 100% by mass of the polyamide resin composition, wherein the relative viscosity of the polyamide resin (A) measured at 25°C in accordance with JIS K6920-2 is 3.2 or more and 4.2 or less The present invention relates to a polyamide resin composition wherein the novolac-type phenolic resin (B) has a softening point temperature of 130°C or lower, and the extract obtained when the polyamide resin composition is extracted for 6 hours by Soxhlet extraction using water as the solvent is 1.5% by mass or less relative to 100% by mass of the polyamide resin composition used for extraction.

[0010] In this specification, "substantially absent" means that the substance is not present to an extent that would alter the properties of the polyamide resin composition or the functions and properties of the molded articles obtained from the polyamide resin composition, but it does not exclude the possibility of the substance being present to an extent that does not impair the functions or properties.

[0011] <Polyamide resin (A)> The polyamide resin composition contains polyamide resin (A). Examples of the polyamide resin (A) include an aliphatic homopolyamide resin (A-1), an aliphatic copolymer polyamide resin (A-2), an aromatic homopolyamide resin (A-3), and an aromatic copolymer polyamide resin (A-4). These may be used alone or in combination of two or more. Among these, from the viewpoint of moldability, the polyamide resin (A) preferably contains at least one selected from the group consisting of the aliphatic homopolyamide resin (A-1) and the aliphatic copolymer polyamide resin (A-2), and more preferably contains the aliphatic homopolyamide resin (A-1).

[0012] (A-1) Aliphatic homopolyamide resin The aliphatic homopolyamide resin (A-1) is a polyamide resin composed of one type of aliphatic structural unit. The aliphatic homopolyamide resin (A-1) may be composed of at least one of one type of lactam and an aminocarboxylic acid that is a hydrolyzate of the lactam, or may be composed of a combination of one type of diamine and one type of dicarboxylic acid. Here, the combination of the diamine and the dicarboxylic acid is regarded as one type of monomer in the combination of one type of diamine and one type of dicarboxylic acid.

[0013] Examples of the lactam include ε-caprolactam, enanthlactam, undecanolactam, α-pyrrolidone, α-piperidone, laurolactam, and the like. Among these, from the viewpoint of polymerization production, one selected from the group consisting of ε-caprolactam, undecanolactam, and laurolactam is preferred. Examples of the aminocarboxylic acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. Among these, from the viewpoint of polymerization production, one selected from the group consisting of 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid is preferred.

[0014] Examples of the diamine include aliphatic diamines such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, eicosanediamine, 2-methyl-1,8-octanediamine, 2,2,4 / 2,4,4-trimethylhexamethylenediamine; alicyclic diamines such as 1,3- / 1,4-cyclohexyldiamine, bis(4-aminocyclohexyl)methane, bis(4-aminocyclohexyl)propane, bis(3-methyl-4-aminocyclohexyl)methane, (3-methyl-4-aminocyclohexyl)propane, 1,3- / 1,4-bisaminomethylcyclohexane, 5-amino-2,2,4-trimethyl-1-cyclopentanemethylamine, 5-amino-1,3,3-trimethylcyclohexanemethylamine, bis(aminopropyl)piperazine, bis(aminoethyl)piperazine, norbornanedimethyleneamine, etc. Among these, from the viewpoint of polymerization productivity, aliphatic diamines are preferred, and hexamethylenediamine is more preferred.

[0015] Examples of the dicarboxylic acid include aliphatic dicarboxylic acids such as 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, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, eicosanedioic acid; alicyclic dicarboxylic acids such as 1,3- / 1,4-cyclohexanedicarboxylic acid, dicyclohexane methane-4,4'-dicarboxylic acid, norbornanedicarboxylic acid, etc. Among these, aliphatic dicarboxylic acids are preferred, one selected from the group consisting of adipic acid, sebacic acid and dodecanedioic acid is more preferred, and adipic acid or dodecanedioic acid is even more preferred.

[0016] Specifically, as aliphatic homopolyamide resins (A-1), polycaprolactam (polyamide 6), polyenanthractam (polyamide 7), polyundecanelactam (polyamide 11), polylaurolactam (polyamide 12), polyhexamethyleneadipamide (polyamide 66), polytetramethylenedodecadamide (polyamide 412), polypentamethyleneazeramide (polyamide 59), polypentamethylenesebamide (polyamide 510), polypentamethylenedodecadamide (polyamide 512), polyhexamethyleneazeramide (polyamide 69), polyhexamethylenesebamide (polyamide 610), polyhexamethylenedodecadamide (polyamide 612), polynonate Examples include methylene adipamide (polyamide 96), polynonameethylene azeramide (polyamide 99), polynonameethylene sebaamide (polyamide 910), polynonameethylene dodecamide (polyamide 912), polydecamethylene adipamide (polyamide 106), polydecamethylene azeramide (polyamide 109), polydecamethylene decamido (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene azeramide (polyamide 129), polydodecamethylene sebaamide (polyamide 1210), polydodecamethylene dodecamide (polyamide 1212), and polyamide 122. Aliphatic homopolyamide resin (A-1) may be used alone or as a mixture of two or more types.

[0017] In particular, from the viewpoint of polymerization productivity, the aliphatic homopolyamide resin (A-1) is preferably at least one selected from the group consisting of polyamide 6, polyamide 11, polyamide 12, polyamide 66, polyamide 610, and polyamide 612, more preferably at least one selected from polyamide 6, polyamide 11, polyamide 12, polyamide 610, and polyamide 612, and even more preferably polyamide 6.

[0018] Examples of known polyamide manufacturing apparatuses for producing aliphatic homopolyamide resin (A-1) include batch reaction vessels, single-tank or multi-tank continuous reaction apparatuses, tubular continuous reaction apparatuses, single-screw kneading extruders, twin-screw kneading extruders, and other kneading reaction extruders. Polymerization can be carried out using known methods such as melt polymerization, solution polymerization, and solid-phase polymerization, by repeatedly operating under atmospheric pressure, reduced pressure, and increased pressure. These polymerization methods can be used individually or in appropriate combinations.

[0019] The relative viscosity of the aliphatic homopolyamide resin (A-1) is measured in accordance with JIS K 6920-2 by dissolving 1 g of aliphatic homopolyamide in 100 ml of 96% concentrated sulfuric acid and measuring it at 25°C. The relative viscosity of the aliphatic homopolyamide is preferably between 1.9 and 5.0, more preferably between 2.3 and 4.5, and even more preferably between 2.7 and 4.3. Furthermore, from the viewpoint of improving the effects of the present invention, a relative viscosity of 3.2 and 4.2 is particularly preferred. When the relative viscosity is within the above range, the moldability is good and the mechanical properties are also good.

[0020] The terminal amino group concentration of the aliphatic homopolyamide resin (A-1) is determined by neutralization titration after dissolving it in a mixed solvent of phenol and methanol. The terminal amino group concentration of the aliphatic homopolyamide resin (A-1) is preferably 30 μmol / g or more, and more preferably 30 μmol / g or more and 50 μmol / g or less.

[0021] (A-2) Aliphatic copolymer polyamide resin Aliphatic copolymer polyamide resin (A-2) is a polyamide resin composed of two or more aliphatic structural units. Aliphatic copolymer polyamide resin (A-2) is a copolymer of monomers selected from the group consisting of combinations of diamines and dicarboxylic acids, lactams, and aminocarboxylic acids. Here, a combination of diamines and dicarboxylic acids is considered as one monomer when it is a combination of one type of diamine and one type of dicarboxylic acid.

[0022] Examples of diamines include those similar to those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). Diamines may be used individually or in appropriate combinations of two or more types. Among these, from the viewpoint of polymerization productivity, at least one selected from the group consisting of aliphatic diamines is preferred, at least one selected from the group consisting of linear aliphatic diamines is more preferred, and hexamethylenediamine is even more preferred.

[0023] Examples of dicarboxylic acids include those similar to those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). Dicarboxylic acids may be used individually or in combination of two or more types as appropriate. Among these, aliphatic dicarboxylic acids are preferred, at least one selected from the group consisting of adipic acid, sebacic acid, and dodecanedionic acid is more preferred, and at least one selected from the group consisting of adipic acid and dodecanedionic acid is even more preferred.

[0024] Examples of lactams include those similar to those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). Lactams may be used individually or in combination of two or more types as appropriate. Among these, at least one selected from the group consisting of ε-caprolactam, undecanlactam, and laurolactam is preferred from the viewpoint of polymerization production.

[0025] Furthermore, examples of aminocarboxylic acids include those similar to those exemplified as raw materials for the aliphatic homopolyamide resin (A-1). One type of aminocarboxylic acid may be used alone, or two or more types may be used in appropriate combinations. Among these, from the viewpoint of polymerization production, at least one selected from the group consisting of 6-aminocaproic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid is preferred.

[0026] Specifically, as aliphatic copolymer polyamide resin (A-2), caprolactam / hexamethylenediaminoadipic acid copolymer (polyamide 6 / 66), caprolactam / hexamethylenediaminoazelaic acid copolymer (polyamide 6 / 69), caprolactam / hexamethylenediaminosebacic acid copolymer (polyamide 6 / 610), caprolactam / hexamethylenediaminoundecanoic acid copolymer (polyamide 6 / 611), caprolactam / hexamethylenediaminododecanoic acid copolymer (polyamide 6 / 612), caprolactam / aminoundecanoic acid copolymer Examples of aliphatic copolymer polyamides include canic acid copolymers (polyamide 6 / 11), caprolactam / laurolactam copolymers (polyamide 6 / 12), caprolactam / hexamethylenediaminoadipic acid / laurolactam copolymers (polyamide 6 / 66 / 12), caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminosebacic acid copolymers (polyamide 6 / 66 / 610), and caprolactam / hexamethylenediaminoadipic acid / hexamethylenediaminododecanedicarboxylic acid copolymers (polyamide 6 / 66 / 612). The aliphatic copolymer polyamide resin (A-2) may be used alone or as a mixture of two or more types.

[0027] Among these, from the viewpoint of suppressing the water absorption rate of the molded product and maintaining mechanical strength, at least one selected from the group consisting of polyamide 6 / 66, polyamide 6 / 12, and polyamide 6 / 66 / 12 is preferred, at least one selected from the group consisting of polyamide 6 / 66 and polyamide 6 / 66 / 12 is more preferred, and polyamide 6 / 66 is particularly preferred.

[0028] The manufacturing apparatus and polymerization method for aliphatic copolymer polyamide resin (A-2) are similar to those exemplified in the section on aliphatic homopolyamide resin (A-1).

[0029] The relative viscosity of the aliphatic copolymer polyamide resin (A-2) is preferably 1.9 to 5.0, more preferably 2.3 to 4.5, and even more preferably 2.7 to 4.3, in accordance with JIS K 6920-2, when measured at 25°C after dissolving 1g of aliphatic copolymer polyamide in 100ml of 96% concentrated sulfuric acid, from the viewpoint of moldability and mechanical properties. Furthermore, from the viewpoint of improving the effects of the present invention, a relative viscosity of 3.2 to 4.2 is particularly preferred. When the relative viscosity is within the above range, the moldability is good and the mechanical properties are also good.

[0030] The terminal amino group concentration of the aliphatic copolymer polyamide resin (A-2) is determined by neutralization titration after dissolving it in a mixed solvent of phenol and methanol. The terminal amino group concentration of the aliphatic copolymer polyamide resin (A-2) is preferably 30 μmol / g or more, and more preferably 30 μmol / g or more and 50 μmol / g or less. A terminal amino group concentration within this range is preferable in terms of adhesion to reinforcing materials and adhesion to other resins.

[0031] (A-3) Aromatic homopolyamide resin Aromatic homopolyamide resin (A-3) is an aromatic polyamide resin consisting of one type of structural unit derived from aromatic monomer components. For example, it is a polyamide resin obtained by polycondensation of aliphatic dicarboxylic acid and aromatic diamine, aromatic dicarboxylic acid and aliphatic diamine, or aromatic dicarboxylic acid and aromatic diamine as raw materials. Here, a combination of diamine and dicarboxylic acid is considered as one type of monomer when it is a combination of one type of diamine and one type of dicarboxylic acid.

[0032] Examples of aliphatic diamines and aliphatic dicarboxylic acids used as raw materials include those exemplified as raw materials for the aliphatic homopolyamide resin (A-1) described above, and also include those exemplified as alicyclic diamines and alicyclic dicarboxylic acids. Examples of aromatic diamines include metaxylylenediamine and paraxylylenediamine, while examples of aromatic dicarboxylic acids include naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid.

[0033] Specific examples of aromatic homopolyamide resins (A-3) include polynonanemethylene terephthalamide (polyamide 9T), polyhexamethylene terephthalamide (polyamide 6T), polyhexamethylene isophthalamide (polyamide 6I), and polyxylylene adipamide (polyamide MXD6). Aromatic homopolyamide resins (A-3) may be used individually or as a mixture of two or more types.

[0034] The manufacturing apparatus and polymerization method for aromatic homopolyamide resin (A-3) are similar to those exemplified in the section on aliphatic homopolyamide resin (A-1).

[0035] In the present invention, there are no particular restrictions on the degree of polymerization of the (A-3) aromatic homopolyamide resin. However, from the viewpoint of moldability and mechanical properties, according to JIS K 6920-2, the relative viscosity of the (A-3) aromatic copolymerized polyamide, measured at a resin temperature of 25°C, is preferably 1.9 or more and 5.0 or less, more preferably 2.3 or more and 4.5 or less, and even more preferably 2.7 or more and 4.3 or less. Furthermore, from the viewpoint of improving the effects of the present invention, a relative viscosity of 3.2 or more and 4.2 or less is particularly preferred.

[0036] (A-4) Aromatic copolymer polyamide resin Aromatic polyamide is an aromatic polyamide resin containing at least one aromatic monomer component. For example, it is a polyamide resin obtained by polycondensation of an aliphatic dicarboxylic acid and an aromatic diamine, an aromatic dicarboxylic acid and an aliphatic diamine, or an aromatic dicarboxylic acid and an aromatic diamine as raw materials. Aromatic copolymer polyamide resin (A-4) is a polyamide resin consisting of two or more constituent units among the above aromatic polyamide resins. Here, a combination of diamine and dicarboxylic acid is considered as one monomer when it is a combination of one type of diamine and one type of dicarboxylic acid.

[0037] Examples of aliphatic diamines and aliphatic dicarboxylic acids used as raw materials include those exemplified as raw materials for the aliphatic homopolyamide resin (A-1) described above, and also include those exemplified as alicyclic diamines and alicyclic dicarboxylic acids. Examples of aromatic diamines include metaxylylenediamine and paraxylylenediamine, while examples of aromatic dicarboxylic acids include naphthalenedicarboxylic acid, terephthalic acid, isophthalic acid, and phthalic acid. These aromatic diamines and aromatic dicarboxylic acids may be used individually or in combination of two or more as appropriate. Furthermore, the aromatic copolymer polyamide resin may contain constituent units derived from lactams and aminocarboxylic acids, and examples of lactams and aminocarboxylic acids include those similar to those exemplified as raw materials for the aliphatic homopolyamide resin (A-1) described above. These lactams and aminocarboxylic acids may be used individually or in combination of two or more.

[0038] Specific examples of aromatic copolymer polyamide resins (A-4) include (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), and polydodecamido Examples include polyhexamethylene terephthalamide copolymer (polyamide 12 / 6T), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6T / 6I), polyhexamethylene adipamide / polycaproamide / polyhexamethylene isophthalamide copolymer (polyamide 66 / 6 / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (polyamide 6T / 6I), and polyhexamethylene terephthalamide / poly(2-methylpentamethylene terephthalamide) copolymer (polyamide 6T / M5T). Aromatic copolymerized polyamide resin (A-4) may be used alone or in combination of two or more types. Among these, polyamide 6T / 6I is preferred.

[0039] The manufacturing apparatus and polymerization method for aromatic copolymer polyamide resin (A-4) is aliphatic Homo Examples similar to those exemplified in the section on polyamide resin (A-1) can be given.

[0040] In the present invention, there are no particular restrictions on the degree of polymerization of the aromatic copolymer polyamide resin (A-4). However, from the viewpoint of moldability and mechanical properties, according to JIS K 6920-2, the relative viscosity of the (A-4) aromatic copolymer polyamide, measured at a resin temperature of 25°C, is preferably 1.9 to 5.0, more preferably 2.3 to 4.5, and even more preferably 2.7 to 4.3. Furthermore, from the viewpoint of improving the effects of the present invention, a relative viscosity of 3.2 to 4.2 is particularly preferred. When the relative viscosity is within the above range, the moldability is good and the mechanical properties are also good.

[0041] The terminal amino group concentration of aromatic copolymer polyamide resin (A-4) is determined by neutralization titration after dissolving it in a mixed solvent of phenol and methanol. The terminal amino group concentration of aromatic copolymer polyamide resin (A-4) is preferably between 20 μmol / g and 60 μmol / g. A terminal amino group concentration within this range is preferable from the viewpoint of adhesion to reinforcing materials and adhesion to other resins.

[0042] The polyamide resin (A) is prepared according to JIS K-6920-2 by dissolving 1 g of polyamide in 100 ml of 96% concentrated sulfuric acid and measuring the relative viscosity at 25°C. The relative viscosity is preferably between 1.9 and 5.0, more preferably between 2.3 and 4.5, and more preferably between 2.7 and 4.3. Furthermore, from the viewpoint of improving the effects of the present invention, a relative viscosity of 3.2 and 4.2 is even more preferable. When the relative viscosity is within the above range, the moldability is good and the mechanical properties are also good.

[0043] If the polyamide resin (A) contains two or more polyamide resins with different relative viscosities (for example, at least one aliphatic homopolyamide resin (A-1) and at least one aliphatic copolymer polyamide resin (A-2)), the relative viscosity of the polyamide resin (A) is preferably measured as described above. However, if the relative viscosity of each polyamide resin and its mixing ratio are known, the average value calculated by summing the values ​​obtained by multiplying each relative viscosity by its mixing ratio may be used as the relative viscosity of the polyamide resin (A).

[0044] The terminal amino group concentration of polyamide resin (A), as determined by neutralization titration after dissolving in a mixed solvent of phenol and methanol, is preferably in the range of 30 μmol / g or more, and more preferably in the range of 30 μmol / g to 50 μmol / g. Within this range, sufficient moldability and mechanical properties can be obtained.

[0045] If the polyamide resin (A) contains two or more polyamide resins with different terminal amino group concentrations (for example, at least one aliphatic homopolyamide resin (A-1) and at least one aliphatic copolymer polyamide resin (A-2)), the terminal amino group concentration in the polyamide resin (A) is preferably measured by the neutralization extraction method described above. However, if the terminal amino group concentration and mixing ratio of each polyamide resin are known, the average value calculated by summing the values ​​obtained by multiplying each terminal amino group concentration by its mixing ratio may be used as the terminal amino group concentration of the polyamide resin (A).

[0046] Polyamide resin (A) is present in an amount of 60 to 95% by mass, preferably 65 to 85% by mass, and more preferably 70 to 80% by mass, of 100% by mass of the polyamide resin composition. If the content of polyamide resin (A) is less than the above range, the moldability deteriorates, and if it is more than the above range, the water absorption rate of the molded product increases and the calcium chloride resistance decreases.

[0047] <Novolac-type phenolic resin (B)> Examples of novolac-type phenolic resins (B) include those produced by condensation polymerization of phenols and aldehydes in the presence of an acidic catalyst. However, this does not include resol-type phenol-formaldehyde produced by condensation polymerization of phenols and aldehydes in the presence of an alkaline catalyst.

[0048] Examples of phenols used in the production of novolac-type phenolic resin (B) include monovalent or polyvalent phenols such as phenol, cresol, trimethylphenol, xylenol, resorcinol, catechol, butylphenol, octylphenol, nonylphenol, phenylphenol, dihydroxybenzene, bisphenol A, and naphthol, as well as their substituted derivatives. These may be used individually or in combination of two or more. Among these, phenol and cresol are preferred, and phenol is more preferred.

[0049] Examples of aldehydes used in the production of novolac-type phenolic resin (B) include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, glyoxal, n-propanal, n-butanal, isopropanal, isobutyraldehyde, 3-methyl-n-butanal, benzaldehyde, p-tolylaldehyde, and 2-phenylacetaldehyde. These may be used individually or in combination of two or more. Among these, formaldehyde and acetaldehyde are preferred, with formaldehyde being more preferred.

[0050] The acidic catalyst is not particularly limited, but examples include oxalic acid, hydrochloric acid, sulfuric acid, phosphoric acid, acetic acid, p-toluenesulfonic acid, phenolsulfonic acid, formic acid, maleic acid, zinc acetate, and zinc octoate.

[0051] Among such novolac-type phenolic resins (B), phenol-formaldehyde resin represented by the following formula (1) is preferred from the viewpoint of mechanical properties and heat resistance. [ka] In formula (1) above, n is preferably 1 to 200, more preferably 1 to 50, and even more preferably 5 to 20.

[0052] The number-average molecular weight of the novolac-type phenolic resin (B) is preferably 500 to 5,000, and more preferably 300 to 3,000, from the viewpoint of moldability and heat resistance. The number-average molecular weight shall be the number-average molecular weight calculated based on the hydroxyl value measured in accordance with JIS K 1557. Specifically, the hydroxyl value is measured and calculated using the terminal group determination method, with the formula being (56.1 × 1000 × valency) / hydroxyl value (in this formula, the unit of hydroxyl value is [mgKOH / g]). In the above formula, the valency is the number of hydroxyl groups in one molecule.

[0053] The softening point temperature of novolac-type phenolic resin (B) is 130°C or lower, preferably between 110 and 130°C, and more preferably between 120 and 130°C. The softening point temperature is determined by the ring-and-sphere method of softening point measurement based on JIS K6910. Having the softening point temperature of novolac-type phenolic resin (B) within the above range results in good moldability.

[0054] Examples of commercially available novolac-type phenolic resins include HF-4M and NC58 manufactured by Meiwa Kasei.

[0055] In 100% by mass of the polyamide resin composition, the novolac-type phenolic resin (B) is contained in an amount of 5 to 40% by mass, preferably 10 to 30% by mass. If the amount of novolac-type phenolic resin is less than the above range, the water absorption rate of the molded product increases and the calcium chloride resistance deteriorates. If the content of novolac-type phenolic resin is more than the above range, the heat resistance and mechanical properties of the polyamide composition decrease.

[0056] <Additives> Depending on the purpose, the polyamide resin composition may appropriately contain as optional components dyes, pigments, fibrous reinforcements, particulate reinforcements, plasticizers, antioxidants, heat resistant agents, foaming agents, weather resistant agents, crystal nucleating agents, crystallization accelerators, mold release agents, lubricants, antistatic agents, flame retardants, flame retardant aids, colorants, and other functional additives. Any additive may be included in the polyamide resin composition in an amount of preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass, of 100% by mass.

[0057] The polyamide resin composition may contain thermoplastic resins other than polyamide resin (A) and novolac-type phenolic resin (B). From the viewpoint of mechanical properties and moldability, the amount of thermoplastic resins other than polyamide resin (A) and novolac-type phenolic resin (B) is preferably 2% by mass or less, more preferably less than 0.1% by mass, and even more preferably none, per 100% by mass of the polyamide resin composition. In other words, the polyamide resin composition preferably contains novolac-type phenolic resin (B) as the main component of the thermoplastic resin other than polyamide resin (A), and preferably contains 90% by mass or more of novolac-type phenolic resin (B) per 100% by mass of the thermoplastic resin other than polyamide resin (A), and more preferably contains 95% by mass or more. Furthermore, it is preferable that the polyamide resin composition is substantially free of ethylene-based elastomers, because the inclusion of ethylene-based elastomers reduces its heat resistance.

[0058] <Method for producing 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 polyamide resin (A), novolac-type phenolic resin (B), and other optional components, commonly known melt-mixing machines such as single-screw or twin-screw extruders, Banbury mixers, kneaders, and mixing rolls can be used. For example, any of the following methods may be used: a method in which all raw materials are blended and then melt-mixed using a twin-screw extruder; a method in which some raw materials are blended, then melt-mixed, and then the remaining raw materials are blended and melt-mixed again; or a method in which some raw materials are blended, and then the remaining raw materials are mixed using a side feeder during melt-mixing.

[0059] <Properties of polyamide resin compositions> When a polyamide resin composition is extracted for 6 hours using a Soxhlet extraction method with water as the solvent, the extracted amount is 1.5% by mass or less, preferably 1.2% by mass or less, relative to 100% by mass of the polyamide resin composition used for extraction. When a polyamide resin composition is extracted for 3 hours using the Soxhlet extraction method with methanol as the solvent, the extracted amount is 7.5% by mass or less relative to 100% by mass of the polyamide resin composition used for extraction. It is preferable to , the amount must be 6.8% or less twist preferable. The extraction method used was the Soxhlet extraction method. The extracted amount was calculated using the formula: (mass of polyamide resin composition before boiling - mass of residue after boiling and vacuum drying) / mass of polyamide resin composition before boiling. The amount of hot water extraction and the amount of hot methanol extraction can be adjusted by selecting a novolac resin and appropriately adjusting the amount of each component. If the amount extracted by the Soxhlet extraction method using water or methanol as the solvent exceeds the aforementioned range, a large amount of polyamide resin and novolac resin will decompose from the molded product, resulting in the elution of monomers and other materials. This can lead to the molded product becoming brittle or monomers bleeding out onto the surface of the molded product.

[0060] [Molded articles of polyamide resin compositions and their uses] Polyamide resin compositions can be suitably used in the manufacture of injection-molded products by injection molding, extruded products by extrusion molding, blow-molded products by blow molding, and rotationally molded products by rotational molding. Since polyamide resin compositions have good injection moldability, they can be suitably used in injection-molded products.

[0061] There are no particular restrictions on the method for producing injection-molded articles from polyamide resin compositions by injection molding, and known methods can be used. For example, methods conforming to ISO 294-1 can be considered.

[0062] There are no particular limitations on the method for producing extruded articles from polyamide resin compositions by extrusion molding, and known methods can be used. Furthermore, it is possible to obtain a multilayer structure by co-extruding with polyolefins such as polyethylene or other thermoplastic resins, followed by blow molding. In this case, it is also possible to provide an adhesive layer between the polyamide resin composition layer and the other 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 either the outer layer or the inner layer.

[0063] There are no particular limitations on the method for producing blow-molded articles from a polyamide resin composition by blow molding, and known methods can be used. Generally, a parison can be formed using a conventional blow molding machine, and then blow molding can be performed. The preferred resin temperature during parison formation is preferably in the temperature range of 10°C to 70°C higher than the melting point of the polyamide resin composition.

[0064] There are no particular limitations on the method for producing rotationally molded articles from polyamide resin compositions by rotational molding, and known methods can be used. For example, the method described in International Publication No. 2019 / 054109 can be considered.

[0065] While not particularly limited, suitable applications include automotive parts such as spoilers, air intake ducts, intake manifolds, resonators, fuel tanks, gas tanks, hydraulic oil tanks, fuel filler tubes, fuel delivery pipes, and various other hoses, tubes, and tanks; mechanical parts such as power tool housings and pipes; electrical and electronic components such as tanks, tubes, hoses, and films; household and office supplies; building materials; and furniture parts. Among these, polyamide resin compositions are preferred for use in automotive parts due to their excellent resistance to calcium chloride.

[0066] Furthermore, because the polyamide resin composition has excellent gas barrier properties, it is suitably used in molded articles that come into contact with high-pressure gases, such as tanks, tubes, hoses, films, etc. The type of gas is not particularly limited, and examples include hydrogen, nitrogen, oxygen, helium, methane, butane, propane, etc. Gases with low polarity are preferred, and hydrogen, nitrogen, and methane are particularly preferred.

[0067] Furthermore, it is also possible to obtain a multilayer structure by co-extruding with polyolefins such as polyethylene or other thermoplastic resins, followed by blow molding. Polyamide resin composition It is also possible to provide an adhesive layer between the layer and other thermoplastic resin layers such as polyolefin. In the case of a multilayer structure, the present invention Polyamide resin composition It can be used for either the outer or inner layer. [Examples]

[0068] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0069] The measurement methods in the examples and comparative examples are as follows. <Relative viscosity> The values ​​were measured in accordance with JIS K6920-2, by dissolving 1 g of polyamide in 100 ml of 96% concentrated sulfuric acid and measuring at 25°C.

[0070] <Softening point temperature> The softening point temperature was determined by the ring-and-spherical method of softening point measurement based on JIS K6910.

[0071] <Hot water extraction amount> The polyamide resin composition was boiled with hot water for 6 hours using a Soxhlet extraction method with water as the solvent. After removing the hot water, the residue was dried in a vacuum dryer at 90°C for 16 hours. The amount of residue was weighed, and the difference obtained by subtracting the mass of the residue after boiling and vacuum drying from the mass of the polyamide resin composition before boiling was divided by the mass of the polyamide resin composition before boiling to obtain the value of the hot water extract per 100% by mass of the polyamide resin composition.

[0072] <Amount of thermal methanol extracted> The polyamide resin composition was boiled with hot methanol for 3 hours using a Soxhlet extraction method with methanol as the solvent. After removing the hot methanol, the residue was dried in a vacuum dryer at 90°C for 16 hours. The amount of residue was weighed, and the difference obtained by subtracting the mass of the residue after boiling and vacuum drying from the mass of the polyamide resin composition before boiling was divided by the mass of the polyamide resin composition before boiling to obtain the value of the hot methanol extract per 100% by mass of the polyamide resin composition.

[0073] <Calcium chloride tolerance> ISO TYPE-A test specimens obtained by injection molding of polyamide resin compositions were used. Gauze was placed on the specimen, saturated calcium chloride solution was applied, and the specimens were left at 80°C and 90% RH for 24 hours for pretreatment. After pretreatment, the specimens were heated in a 100°C oven for 2 hours, followed by 20 hours in a constant temperature bath at 80°C and 90% RH. This constituted one test cycle. After each cycle, the presence or absence of cracks in the specimens was observed using a Keyence VHX-5000 digital microscope and evaluated according to the following criteria. ○: No cracks have occurred in the test specimen. ×: Cracks have occurred in the test specimen. Furthermore, only those that did not develop cracks after one cycle were deemed acceptable.

[0074] <Dielectric constant and dielectric loss tangent> A 100mm × 70mm × 2mm thick flat plate was fabricated from a polyamide resin composition using a FANUC T-100D injection molding machine with a clamping force of 100 tons and a screw diameter of 36mm, under the conditions of cylinder temperature 250°C, mold temperature 40°C, and injection speed 50mm / sec. This flat plate was immersed in water at 40°C for 7 days and used as the test specimen. For dielectric constant measurement, an impedance analyzer Agilent 4294A (Agilent Technologies) and a fixture Agilent 16451B (Agilent Technologies) were used. The electrode contact method was employed for measurement, and the dielectric loss tangent was determined at 10GHz.

[0075] <Mechanical properties after water absorption> ISO TYPE-A test specimens of polyamide resin composition were immersed in 40°C water for 168 hours, and the following mechanical properties were measured using the pre-treated specimens. The water absorption rate was calculated from the mass difference of the specimens before and after immersion. (1) Tensile yield stress and tensile fracture nominal strain after water absorption Using the test specimens that had been soaked in 40°C water for 168 hours, measurements were taken at 23°C using an Instron tensile testing machine, model 5567, in accordance with ISO 527. (2) Bending strength and flexural modulus after water absorption The test specimens, which had been soaked in 40°C water for 168 hours, were measured at 23°C using an Instron tensile testing machine, model 5567, in accordance with ISO 178.

[0076] [Examples 1-5, Comparative Examples 1-4] Each component listed in Table 1 was melt-kneaded in a twin-screw kneader TEX44HCT with a cylinder diameter of 44 mm and a L / D ratio of 35, at a cylinder temperature of 250°C, a screw rotation of 160 rpm, and a discharge rate of 50 kg / hrs to produce the target polyamide resin composition pellets. Note that the composition units in the table are in mass%, with the entire resin composition being considered as 100% by mass.

[0077] The ingredients listed in Table 1 were as follows: PA6: Polyamide 6, relative viscosity 3.36 (manufactured by Ube Industries, Ltd.) PA6 / 66: Polyamide 6 / 66, relative viscosity 4.05, polyamide 6 85 mol%, polyamide 66 15 mol% (manufactured by Ube Industries, Ltd.) Novolac-type phenolic resin (1): Softening point temperature: 102°C, Product name HF-4M (manufactured by Meiwa Chemicals), structure represented by formula (1), n ​​= approximately 6.7 Novolac-type phenolic resin (2): Softening point temperature: 125°C, Product name NC58 (manufactured by Meiwa Kasei), structure represented by formula (1), n ​​= approximately 14.6

[0078] [Table 1]

[0079] As shown in Table 1, in Examples 1 to 5, polyamide resin compositions were obtained in which the amount extracted with hot water was 1.5% by mass or less, good calcium chloride resistance, insulating properties, low water absorption, and excellent mechanical properties when water is absorbed. Comparing Examples 1-5 with Comparative Examples 3 and 4, it can be seen that when a polyamide resin composition contains a specific amount of novolac-type phenolic resin within a specific softening point temperature range, it exhibits superior water absorption, calcium chloride resistance, insulation properties, and mechanical properties compared to polyamide resin alone. Comparing Examples 1-5 with Comparative Examples 1 and 2, when the amount extracted with hot water exceeds 1.5% by mass, The mechanical properties of the polyamide resin composition are degraded. Furthermore, high amounts of hot water and hot methanol extraction can lead to bleed-out on the surface of the molded product. Comparing Examples 2 to 4, it can be seen that within the scope of the present invention, a higher amount of novolac-type phenolic resin added results in a higher flexural modulus, lower water absorption, and better insulation and calcium chloride resistance. [Industrial applicability]

[0080] The polyamide resin composition of the present invention has good calcium chloride resistance, insulating properties, low water absorption, and excellent mechanical properties when water is absorbed, making it suitable for use in automotive parts.

Claims

1. A polyamide resin composition comprising 60 to 95% by mass of polyamide resin (A) and 5 to 40% by mass of novolac-type phenolic resin (B) in 100% by mass of the polyamide resin composition, The polyamide resin (A) has a relative viscosity of 3.2 or more and 4.2 or less, as measured at 25°C in accordance with JIS K6920-2. The novolac-type phenolic resin (B) has a softening point temperature of 120 to 130°C. A polyamide resin composition in which, when the polyamide resin composition is extracted for 6 hours by Soxhlet extraction using water as the solvent, the extracted amount is 1.5% by mass or less relative to 100% by mass of the polyamide resin composition used for extraction.

2. The polyamide resin composition according to claim 1, wherein the novolac-type phenolic resin (B) is a novolac-type phenolic resin represented by the following formula (1). 【Transformation 3】 (In equation (1) above, n is between 1 and 200.)

3. The polyamide resin composition according to claim 1 or 2, wherein the polyamide resin (A) comprises at least one selected from the group consisting of aliphatic homopolyamide resin (A-1) and aliphatic copolymer polyamide resin (A-2).

4. The polyamide resin composition according to any one of claims 1 to 3, wherein the polyamide resin composition comprises a novolac-type phenolic resin (B) as the main component, as a thermoplastic resin component other than the polyamide resin (A).

5. A polyamide resin composition according to any one of claims 1 to 4, which is substantially free of ethylene-based elastomers.

6. A molded article of a polyamide resin composition according to any one of claims 1 to 5.

7. A molded product according to claim 6, which is an automobile part.

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