Resin composition for adhesive layer and multi-layer tube

Abstract

The present disclosure pertains to a resin composition for an adhesive layer and the like, the resin composition containing: a polyphenylene sulfide-based resin (A); a polyamide resin (B); a first thermoplastic resin (C) which has at least one functional group selected from among an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester; and a second thermoplastic resin (D) which does not have any of an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester, wherein 80-300 parts by weight of the polyamide resin (B), 20-200 parts by weight of the first thermoplastic resin (C), and 10-100 parts by weight of the second thermoplastic resin (D) are contained with respect to 100 parts by weight of the polyphenylene sulfide-based resin (A), and the concentration of terminal amino groups in the polyamide resin (B) is 48-120 mmol / kg.

Description

[Technical Field]

[0001] The present disclosure relates to a resin composition for an adhesive layer and a multilayer tube. [Background technology]

[0002] Conventionally, multilayer tubes having three or more layers laminated together have been used as automobile parts and the like. Known examples of such multilayer tubes include a first layer formed from a resin composition for the first layer containing a polyamide resin, a second layer formed from a resin composition for the second layer containing a polyphenylene sulfide resin, and an adhesive layer disposed between the first layer and the second layer to bond the first layer to the second layer (for example, Patent Document 1).

[0003] The adhesive layer is formed from a resin composition for adhesive layers. In Patent Document 1, the resin composition for the adhesive layer contains a polyphenylene sulfide resin (A), a polyamide resin (B), a first thermoplastic resin (C) having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester, and a second thermoplastic resin (D) having none of an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester. Furthermore, in Patent Document 1, the resin composition for the adhesive layer contains 80 to 300 parts by weight of the polyamide resin (B), 20 to 200 parts by weight of the first thermoplastic resin (C), and 10 to 100 parts by weight of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide resin (A).

[0004] The multilayer tube has a second layer containing a polyphenylene sulfide resin, and thus has excellent heat resistance, hot water resistance, chemical resistance, flame retardancy, electrical properties, and the like. Furthermore, the multilayer tube has a first layer containing a polyamide resin, and therefore has excellent mechanical properties. Furthermore, the multilayer tube has the adhesive layer, which enhances the adhesiveness between the first layer and the second layer, making it easier for the first layer and the second layer to exhibit their functions.

[0005] The multilayer tube can be molded by melting the resin composition for the first layer, the resin composition for the second layer, and the resin composition for the adhesive layer, respectively, and co-extruding the melts. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2008-213458 Summary of the Invention [Problem to be solved by the invention]

[0007] Here, if a thin portion occurs in the adhesive layer, there is a risk that the adhesiveness between the first layer and the second layer may be reduced due to that portion, for example. On the other hand, if thick portions are formed in the adhesive layer, for example, the volume proportions of the first layer and the second layer in the entire multilayer tube may become smaller, and the properties of the first layer and the second layer may not be fully exhibited. Therefore, it is desirable that the thickness of the adhesive layer varies little.

[0008] However, there has been no sufficient research conducted to date into a resin composition for an adhesive layer that can easily suppress variations in the thickness of an adhesive layer when the adhesive layer is formed from the resin composition for an adhesive layer by melt extrusion molding.

[0009] Therefore, the present disclosure aims to provide a resin composition for an adhesive layer that can easily suppress variation in the thickness of an adhesive layer when an adhesive layer is formed from the resin composition for an adhesive layer by melt extrusion molding, and to provide a multilayer tube with little variation in the thickness of the adhesive layer. [Means for solving the problem]

[0010] The first aspect of the present disclosure is a composition comprising a polyphenylene sulfide-based resin (A), a polyamide resin (B); a first thermoplastic resin (C) having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate salt, and a carboxylate ester; and a second thermoplastic resin (D) having no epoxy group, acid anhydride group, carboxyl group, carboxylate salt, or carboxylate ester, The composition contains 80 to 300 parts by weight of the polyamide resin (B), 20 to 200 parts by weight of the first thermoplastic resin (C), and 10 to 100 parts by weight of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide-based resin (A), The present invention relates to a resin composition for an adhesive layer, wherein the polyamide resin (B) has a terminal amino group concentration of 48 to 120 mmol / kg. Preferably, the polyamide resin (B) has a melt mass flow rate at 230° C. of 1 to 50 g / 10 min. Preferably, the polyamide resin (B) contains at least one of polyamide 11 and polyamide 12. Preferably, the resin composition for an adhesive layer has a matrix-domain structure including a matrix and a domain, The polyamide resin (B) is contained in the matrix, The polyphenylene sulfide resin (A) is contained in the domain.

[0011] The second aspect of the present disclosure is a multilayer tube in which three or more layers are laminated, a first layer containing a polyamide resin; a second layer that is disposed closer to an inner circumferential surface of the multilayer tube than the first layer and contains a polyphenylene sulfide resin; an adhesive layer disposed between the first layer and the second layer and adhering the first layer to the second layer; The adhesive layer relates to a multi-layer tube formed from the resin composition for adhesive layers. Preferably, the polyamide resin in the first layer includes at least one of polyamide 11 and polyamide 12. Preferably, the second layer further contains an epoxy-modified thermoplastic resin in an amount of 1 to 50 parts by weight per 100 parts by weight of the polyphenylene sulfide resin. [Effects of the Invention]

[0012] According to the present disclosure, when an adhesive layer is formed from a resin composition for an adhesive layer by melt extrusion molding, variation in the thickness of the adhesive layer can be suppressed. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view of a multi-layer tube according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings.

[0015] Note that the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other modifications of the configurations are possible as appropriate within the scope of the gist of this disclosure. The present disclosure is not limited by the embodiments, but is limited only by the scope of the claims. Additionally, each feature disclosed herein can be combined with any other feature disclosed herein.

[0016] <Resin composition for adhesive layer according to this embodiment> The resin composition for adhesive layer according to this embodiment contains a polyphenylene sulfide resin (A), a polyamide resin (B), a first thermoplastic resin (C) having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester, and a second thermoplastic resin (D) having none of an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylic acid ester. Furthermore, the resin composition for adhesive layer according to this embodiment contains 80 to 300 parts by weight of the polyamide resin (B), 20 to 200 parts by weight of the first thermoplastic resin (C), and 10 to 100 parts by weight of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide-based resin (A). The polyamide resin (B) has a terminal amino group concentration of 48 to 120 mmol / kg.

[0017] The resin composition for adhesive layers according to this embodiment is used to produce a multi-layer tube. The multilayer tube is a multilayer tube in which three or more layers are laminated. The multilayer tube also includes a first layer containing a polyamide resin, a second layer containing a polyphenylene sulfide resin and disposed closer to the inner surface of the multilayer tube than the first layer, and an adhesive layer disposed between the first layer and the second layer and bonding the first layer to the second layer. The adhesive layer is formed from the resin composition for adhesive layer according to this embodiment.

[0018] The resin composition for an adhesive layer according to this embodiment preferably has a matrix-domain structure containing a matrix and domains. It is also preferable that the polyamide resin (B) is contained in the matrix, and the polyphenylene sulfide resin (A) is contained in the domain. The phrase "the polyamide resin (B) is contained in the matrix" means that "the polyamide resin (B) is contained in the matrix in a larger amount than in the domains." Also, the phrase "the polyphenylene sulfide resin (A) is contained in the domains" means that "the polyphenylene sulfide resin (A) is contained in the domains in a larger amount than in the matrix." In the resin composition for an adhesive layer according to this embodiment, the domains contain the polyphenylene sulfide resin (A), which reduces the particle size of the domains and increases the surface area of ​​the domains, thereby enabling the resin composition for an adhesive layer according to this embodiment to firmly bond the first layer and the second layer.

[0019] (Polyphenylene sulfide resin (A)) The polyphenylene sulfide resin (A) is a polymer containing a unit represented by the following formula (1).

[0020] [ka]

[0021] The polyphenylene sulfide resin (A) may contain units other than the units represented by the above formula (1). Examples of units other than the unit represented by the above formula (1) include units represented by the following formulas (2) to (8).

[0022] [ka]

[0023] [ka]

[0024] [ka]

[0025] [ka]

[0026] [ka]

[0027] [ka]

[0028] [ka]

[0029] From the viewpoint of heat resistance, the polyphenylene sulfide resin (A) preferably contains 70 mol % or more, more preferably 90 mol % or more of the repeating unit represented by the above formula (1).

[0030] Examples of the polyphenylene sulfide resin (A) include polyphenylene sulfide resins having a relatively small molecular weight obtained by a production method typified by that disclosed in Japanese Patent Publication No. 45-3368, and essentially linear, relatively high-molecular-weight polyphenylene sulfide resins obtained by a production method typified by that disclosed in Japanese Patent Publication No. 52-12240. Furthermore, the polyphenylene sulfide-based resin (A) may be a polyphenylene sulfide-based resin obtained by the method described in the above-mentioned Japanese Patent Publication No. 45-3368 and then heated in an oxygen atmosphere to polymerize it. Furthermore, as the polyphenylene sulfide-based resin (A), a polyphenylene sulfide-based resin may be used which is highly polymerized by adding a crosslinking agent (e.g., peroxide) to a polyphenylene sulfide-based resin obtained by the method described in JP-B-45-3368 and heating the resulting mixture.

[0031] In the present embodiment, a polyphenylene sulfide-based resin obtained by any method can be used as the polyphenylene sulfide-based resin (A), but an essentially linear polyphenylene sulfide-based resin having a relatively high molecular weight is preferably used.

[0032] The polyphenylene sulfide resin (A) is preferably a deionized polyphenylene sulfide resin. By washing the polyphenylene sulfide resin with an aqueous acid solution or an organic solvent, a deionized polyphenylene sulfide resin can be obtained. Examples of the cleaning method include immersing the polyphenylene sulfide-based resin in an acid aqueous solution or an organic solvent. Alternatively, the acid aqueous solution or organic solvent may be stirred while the polyphenylene sulfide-based resin is immersed in the acid aqueous solution or organic solvent. Alternatively, the acid aqueous solution or organic solvent may be heated while the polyphenylene sulfide-based resin is immersed in the acid aqueous solution or organic solvent.

[0033] In order to reduce the amount of acid and salt remaining in the polyphenylene sulfide resin that has been washed with the aqueous acid solution, the polyphenylene sulfide resin that has been washed with the aqueous acid solution is preferably washed with water (for example, warm water). In order to prevent the effects of deionization from being impaired, it is preferable to use distilled water or deionized water for washing.

[0034] The acid contained in the acid aqueous solution is not particularly limited as long as it does not have the effect of decomposing the polyphenylene sulfide resin, and examples thereof include acetic acid, hydrochloric acid, sulfuric acid, phosphoric acid, silicic acid, carbonic acid, propylic acid, etc. As the acid, acetic acid and hydrochloric acid are preferred. As the acid, acids that decompose polyphenylene sulfide-based resins (such as nitric acid) are not preferred.

[0035] For example, when acetic acid is used as the acid contained in the acid aqueous solution, the polyphenylene sulfide resin can be sufficiently deionized by immersing the polyphenylene sulfide resin powder in the acid aqueous solution adjusted to about pH 4 and heated to 80 to 90°C, and stirring the solution for 30 minutes or more.

[0036] The organic solvent used for washing the polyphenylene sulfide resin is not particularly limited as long as it does not have the action of decomposing the polyphenylene sulfide resin, and examples thereof include nitrogen-containing polar solvents (e.g., N-methylpyrrolidone, dimethylformamide, dimethylacetamide, 1,3-dimethylimidazolidinone, hexamethylphosphoramide, piperadinones, etc.), sulfoxides (e.g., dimethyl sulfoxide, etc.), sulfones (e.g., dimethyl sulfone, sulfolane, etc.), ketone solvents (e.g., acetone, methyl ethyl ketone, diethyl ketone, acetophenone, etc.), ether solvents (e.g., dimethyl ether, , dipropyl ether, dioxane, tetrahydrofuran, etc.), halogenated solvents (for example, chloroform, methylene chloride, trichloroethylene, ethylene dichloride, perchloroethylene, monochloroethane, dichloroethane, tetrachloroethane, perchloroethane, chlorobenzene, etc.), alcohols (for example, methanol, ethanol, propanol, butanol, pentanol, ethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, etc.), phenolic solvents (for example, phenol, cresol, etc.), aromatic hydrocarbons (benzene, toluene, xylene, etc.), etc. These organic solvents may be used alone or in combination of two or more. Of these organic solvents, N-methylpyrrolidone, acetone, dimethylformamide, and chloroform are preferred.

[0037] The washing temperature when washing a polyphenylene sulfide resin with an organic solvent is not particularly limited, and can be any temperature between room temperature (for example, 25° C.) and about 300° C. Here, the higher the washing temperature, the higher the washing efficiency tends to be, but usually a washing temperature between room temperature and 150° C. is sufficient to obtain the desired effect.

[0038] When washing the polyphenylene sulfide-based resin with an organic solvent, the polyphenylene sulfide-based resin may be washed in a pressure vessel under pressure at a temperature equal to or higher than the boiling point of the organic solvent. There is also no particular limit to the cleaning time. Although it depends on the cleaning conditions, in the case of batch cleaning, a cleaning time of 5 minutes or more usually produces sufficient results. It is also possible to clean using a continuous method.

[0039] In order to reduce the amount of organic solvent remaining in the polyphenylene sulfide resin that has been washed with the organic solvent, the polyphenylene sulfide resin that has been washed with the organic solvent is preferably washed with water (for example, warm water). In order to prevent the effects of deionization from being impaired, it is preferable to use distilled water or deionized water for washing. From the viewpoint of facilitating the reduction of the organic solvent remaining in the polyphenylene sulfide resin by washing with water, the organic solvent is preferably a high-boiling water-soluble organic solvent (such as N-methylpyrrolidone).

[0040] The polyphenylene sulfide-based resin (A) is preferably a modified polyphenylene sulfide-based resin (A). The modified polyphenylene sulfide-based resin (A) may be a polyphenylene sulfide-based resin treated with hot water. The temperature of the hot water is preferably 100°C or higher, more preferably 120°C or higher, even more preferably 150°C or higher, and particularly preferably 170°C or higher. As the hot water, distilled water or deionized water is preferred. In addition, in the hot water treatment, it is preferable to carry out the hot water treatment in an inert atmosphere in order to prevent the end groups of the polyphenylene sulfide resin from decomposing. The hot water treatment is carried out by heating and stirring the polyphenylene sulfide resin and water in a pressure vessel. In the hot water treatment, the amount of the polyphenylene sulfide resin is preferably 200 g or less per 1 L of water at room temperature. Furthermore, in order to remove components remaining in the polyphenylene sulfide resin after the hot water treatment, it is preferable to wash the polyphenylene sulfide resin after the hot water treatment with warm water.

[0041] As the polyphenylene sulfide-based resin (A), any polyphenylene sulfide-based resin (A) having any melt viscosity can be used as long as it can be melt-kneaded with other materials that constitute the resin composition for the adhesive layer according to this embodiment.

[0042] From the viewpoint of improving the moldability of the resin composition for adhesive layer according to this embodiment and making it easier to form a matrix-domain structure in the resin composition for adhesive layer according to this embodiment, the melt mass-flow rate (MFR) of the polyphenylene sulfide resin (A) at 315.5°C is preferably 20 to 600 g / 10 min, more preferably 100 to 300 g / 10 min.

[0043] The melt mass flow rate (MFR) of the polyphenylene sulfide resin (A) at 315.5°C is measured by the method described in ASTM-D1238-70. The melt mass-flow rate (MFR) of the polyphenylene sulfide-based resin (A) at 315.5°C is measured by drying 5 g of the polyphenylene sulfide-based resin (A), heating the dried polyphenylene sulfide-based resin (A) at 315.5°C for 5 minutes, and then applying a load of 5000 g to the heated polyphenylene sulfide-based resin (A).

[0044] (Polyamide resin (B)) Examples of components constituting the polyamide resin (B) include amino acids, lactams, diamines, and dicarboxylic acids. Examples of the amino acid include 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, and para-aminomethylbenzoic acid. Examples of the lactam include ε-caprolactam and ω-laurolactam. Examples of the diamine include aliphatic diamines, alicyclic diamines, aromatic diamines, etc. Specific examples of the diamine include pentamethylenediamine, hexamethylenediamine, 2-methylpentamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine. Examples of the dicarboxylic acid include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, etc. Specific examples of the dicarboxylic acid include adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid. In the present disclosure, nylon homopolymers or copolymers derived from these raw materials can be used either alone or in the form of a mixture.

[0045] As the polyamide resin (B), from the viewpoint of being a polyamide resin excellent in heat resistance (melting point: 150° C. or higher) or a polyamide resin excellent in strength, for example, polycaproamide (polyamide 6), polyhexamethylene adipamide (polyamide 66), polypentamethylene adipamide (polyamide 56), polyhexamethylene sebacamide (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polyunde Canamide (Polyamide 11), Polydodecanamide (Polyamide 12), Polycaproamide / Polyhexamethylene adipamide copolymer (Polyamide 6 / 66), Polycaproamide / Polyhexamethylene terephthalamide copolymer (Polyamide 6 / 6T), Polyhexamethylene adipamide / Polyhexamethylene terephthalamide copolymer (Polyamide 66 / 6T), Polyhexamethylene adipamide / Polyhexamethylene isoflavone Polyamide copolymer (Polyamide 66 / 6I), Polyhexamethylene terephthalamide / Polyhexamethylene isophthalamide copolymer (Polyamide 6T / 6I), Polyhexamethylene terephthalamide / Polydodecanamide copolymer (Polyamide 6T / 12), Polyhexamethylene adipamide / Polyhexamethylene terephthalamide / Polyhexamethylene isophthalamide copolymer (Polyamide 66 / 6T / 6I), Polyamide Examples include silylene adipamide (polyamide MXD6), polyhexamethylene terephthalamide / poly-2-methylpentamethylene terephthalamide copolymer (polyamide 6T / M5T), polynonamethylene terephthalamide (polyamide 9T), polyamide 46, polyamide 1010, polyamide 1012, polyamide MXD10, polyamide 10T, polyamide 10T / 11, polyamide 10T / 12, and mixtures thereof.

[0046] From the viewpoint of moldability, mechanical properties, etc., polyamide 11 and polyamide 12 are preferred as the polyamide resin (B).

[0047] The terminal amino group concentration of the polyamide resin (B) is 48 to 120 mmol / kg, preferably 50 to 115 mmol / kg, and more preferably 52 to 110 mmol / kg.

[0048] When the terminal amino group concentration of the polyamide resin (B) is 48 mmol / kg or more, it becomes easier to suppress variations in the thickness of the adhesive layer. It is presumed that when the terminal amino group concentration of the polyamide resin (B) is 48 mmol / kg or more, the amine terminal groups in the polyamide resin (B) are more likely to react with the functional groups in the first thermoplastic resin (C), which makes it easier to improve the compatibility between the polyamide resin (B) and the first thermoplastic resin (C).It is also presumed that when the resin composition for the adhesive layer is melt-extruded, it is easier to extrude the resin composition for the adhesive layer with a relatively uniform thickness, which makes it easier to suppress variations in the thickness of the adhesive layer.

[0049] When the terminal amino group concentration of the polyamide resin (B) is 120 mmol / kg or less, it becomes easier to suppress variations in the thickness of the adhesive layer. It is presumed that the terminal amino group concentration of the polyamide resin (B) of 120 mmol / kg or less makes it easier to increase the molecular weight of the polyamide resin (B), which makes it easier to increase the viscosity of the resin composition for the adhesive layer. It is also presumed that when the resin composition for the adhesive layer is melt-extruded, the shape of the extruded resin composition for the adhesive layer is more likely to be maintained, making it easier to suppress variations in the thickness of the adhesive layer.

[0050] In the polyamide resin (B), the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (terminal amino group concentration / terminal carboxyl group concentration) is preferably 1-20, more preferably 2-10, and even more preferably 2-5. The resin composition for adhesive layer according to the present embodiment can further reduce the particle size of the domains containing the polyphenylene sulfide resin (A) and further increase the surface area of ​​the domains, by setting the ratio of the terminal amino group concentration to the terminal carboxyl group concentration (terminal amino group concentration / terminal carboxyl group concentration) in the polyamide resin (B) within a range of 1 to 20. As a result, the resin composition for adhesive layer according to the present embodiment can further strengthen the adhesion between the first layer and the second layer.

[0051] The terminal amino group concentration of the polyamide resin (B) can be determined as follows. First, a phenol / ethanol solvent is prepared by mixing phenol and ethanol in a volume ratio of 9:1. Next, the weighed polyamide resin (B) is dissolved in 40 mL of a phenol / ethanol solvent to obtain a first solution. Then, 10 mL of ethanol is added to the first solution to obtain a second solution. Next, the second solution is titrated with an N / 100 aqueous hydrochloric acid solution to determine the terminal amino group concentration of the polyamide resin (B).

[0052] The concentration of terminal amino groups in the polyamide resin can be increased by reacting the carboxyl groups of the polyamide resin with a diamine compound. The diamine compound may, for example, be 1,12-dodecanediamine.

[0053] The terminal carboxyl group concentration of the polyamide resin (B) can be determined as follows. First, a weighed amount of polyamide resin (B) is dissolved in 50 mL of benzyl alcohol in an oil bath at 180° C. to obtain a solution. Next, the solution is titrated with a N / 100 potassium hydroxide-ethanol solution using phenolphthalein as an indicator to determine the terminal carboxyl group concentration of the polyamide resin (B).

[0054] The melt mass flow rate (MFR) of the polyamide resin (B) at 230° C. is preferably 1 to 50 g / 10 min, more preferably 1 to 25 g / 10 min, and even more preferably 1 to 10 g / 10 min. Since the melt mass-flow rate (MFR) of the polyamide resin (B) at 230°C is 1 g / 10 min or more, the resin composition for the adhesive layer according to this embodiment flows easily when melted, and as a result, is easy to mold. By having a melt mass-flow rate (MFR) of the polyamide resin (B) at 230°C of 50 g / 10 min or less, it becomes easier to apply an appropriate discharge pressure when the resin composition for the adhesive layer according to this embodiment is melted and extruded from the die of the extruder, making it easier to further suppress variations in the thickness of the adhesive layer.

[0055] The melt mass flow rate (MFR) of the polyamide resin (B) at 230° C. is measured by the method described in ASTM-D1238-70. The melt mass flow rate (MFR) of the polyamide resin (B) at 230°C is measured by drying 5 g of the polyamide resin (B), heating the dried polyamide resin (B) at 230°C for 5 minutes, and then applying a load of 2,160 g to the heated polyamide resin (B).

[0056] The resin composition for adhesive layer according to this embodiment contains 80 to 300 parts by weight, preferably 100 to 250 parts by weight, of the polyamide resin (B) based on 100 parts by weight of the polyphenylene sulfide resin (A). The resin composition for adhesive layer according to this embodiment contains 80 parts by weight or more of the polyamide resin (B) per 100 parts by weight of the polyphenylene sulfide-based resin (A), thereby making it possible to enhance adhesion to the first layer containing a polyamide resin. The resin composition for adhesive layer according to this embodiment contains 300 parts by weight or less of the polyamide resin (B) per 100 parts by weight of the polyphenylene sulfide-based resin (A), thereby making it possible to enhance adhesion to a second layer containing a polyphenylene sulfide-based resin.

[0057] (First thermoplastic resin (C)) The first thermoplastic resin (C) is a thermoplastic resin having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylate ester. Examples of the first thermoplastic resin (C) include polyolefin copolymers having the functional groups, and fluorine-based copolymers having the functional groups.

[0058] Examples of the polyolefin resin include an epoxy group-containing polyolefin copolymer (C1) and an acid anhydride group-containing polyolefin copolymer (C2).

[0059] The epoxy group-containing polyolefin copolymer (C1) is an olefin copolymer having an epoxy group in a side chain or in the main chain. Note that the epoxy group-containing polyolefin resin (C1) does not include epoxy resins. Examples of the olefin copolymer having an epoxy group in the side chain or main chain include an olefin copolymer having a glycidyl group in the side chain or main chain. Examples of the olefin copolymer having a glycidyl group in the side chain or main chain include a glycidyl ester type olefin copolymer, a glycidyl ether type olefin copolymer, and a glycidyl amine type olefin copolymer. Furthermore, as the olefin copolymer having a glycidyl group, a copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated acid is preferred. Examples of the α-olefin include ethylene, propylene, and butene-1. The glycidyl ester of an α,β-unsaturated acid is a compound represented by the following formula (9).

[0060] [ka]

[0061] In the above formula (9), R represents any one selected from a hydrogen atom and an alkyl group having 1 to 6 carbon atoms.

[0062] Examples of the glycidyl ester of an α,β-unsaturated acid include glycidyl acrylate, glycidyl methacrylate, and glycidyl ethacrylate, with glycidyl methacrylate being particularly preferred. The copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated acid may be any of a random copolymer, a block copolymer, and a graft copolymer.

[0063] Further, examples of the olefin copolymer having an epoxy group in the side chain or main chain include those obtained by subjecting the double bond of a double bond-containing olefin copolymer to epoxy oxidation.

[0064] The epoxy group-containing polyolefin copolymer (C1) may have, as a structural unit, for example, methyl acrylate, methyl methacrylate, acrylonitrile, styrene, vinyl acetate, vinyl ether, or the like.

[0065] The content of epoxy groups in the epoxy group-containing polyolefin copolymer (C1) is preferably 1 to 50% by weight, more preferably 3 to 40% by weight. When the epoxy group content in the epoxy group-containing polyolefin copolymer (C1) is 1% by weight or more, the resin composition for adhesive layer according to this embodiment is more likely to have the matrix-domain structure, and as a result, the first layer and the second layer can be firmly bonded to each other. When the epoxy group content in the epoxy group-containing polyolefin copolymer (C1) is 50% by weight or less, gel is less likely to form when the epoxy group-containing polyolefin copolymer (C1) and the polyphenylene sulfide resin are melt-kneaded. As a result, the resin composition for the adhesive layer according to this embodiment has excellent extrusion stability and moldability, and the mechanical strength of the resin composition for the adhesive layer according to this embodiment is likely to be increased.

[0066] The acid anhydride group-containing polyolefin copolymer (C2) is a polyolefin copolymer modified with an acid anhydride. Examples of polyolefin copolymers before being modified with an acid anhydride include ethylene-propylene copolymer, ethylene-butene copolymer, polybutene, ethylene-propylene-diene copolymer, styrene-butadiene copolymer, polybutadiene, butadiene-acrylonitrile copolymer, polyisoprene, butene-isoprene copolymer, and styrene-ethylene-butadiene-styrene copolymer. Furthermore, the polyolefin copolymer before being modified with an acid anhydride may be any of the polyolefin copolymers listed above, polyethylene, polypropylene, or a copolymer of polystyrene and other monomers. Examples of the other monomers include acrylic acid, methacrylic acid, vinyl acetate, methyl acrylate, methyl methacrylate, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, propyl acrylate, propyl methacrylate, butyl acrylate, butyl methacrylate, etc. Examples of the other monomers also include salts of vinyl acetate with metals (e.g., Na, Zn, K, Ca, Mg, etc.). Examples of the acid anhydride include maleic anhydride, succinic anhydride, and fumaric anhydride. The acid anhydride group-containing polyolefin copolymer (C2) may be a random copolymer, a graft copolymer, a block copolymer, or the like.

[0067] The resin composition for adhesive layer according to this embodiment contains 20 to 200 parts by weight, preferably 30 to 150 parts by weight, of the first thermoplastic resin (C) relative to 100 parts by weight of the polyphenylene sulfide resin (A). The resin composition for adhesive layers according to this embodiment contains 20 parts by weight or more of the first thermoplastic resin (C) relative to 100 parts by weight of the polyphenylene sulfide-based resin (A), thereby increasing the melt viscosity of the resin composition for adhesive layers and providing excellent moldability. Furthermore, the resin composition for adhesive layers according to this embodiment also has improved impact resistance due to this configuration. The resin composition for adhesive layer according to this embodiment contains 200 parts by weight or less of the first thermoplastic resin (C) per 100 parts by weight of the polyphenylene sulfide-based resin (A), which makes it less likely for gel to form when melt-kneaded with the polyphenylene sulfide-based resin (A), resulting in excellent extrusion stability, moldability, mechanical strength, and heat resistance.

[0068] The first thermoplastic resin (C) may be one type alone or two or more types. The first thermoplastic resin (C) preferably contains an epoxy group-containing polyolefin resin (C1) and the acid anhydride group-containing polyolefin resin (C2). The weight ratio of the acid anhydride group-containing polyolefin resin (C2) to the epoxy group-containing polyolefin resin (C1) is preferably 1 / 10 to 10 / 1, more preferably 1 / 5 to 10 / 1.

[0069] The first thermoplastic resin (C) is a concept that does not include either the polyphenylene sulfide resin (A) or the polyamide resin (B).

[0070] (Second Thermoplastic Resin (D)) Examples of the second thermoplastic resin (D) that does not have any of an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate, and a carboxylate ester include polyolefin resins, diene resins, hydrogenated diene resins, and acrylic resins. Examples of the polyolefin resin include ethylene-propylene copolymer, ethylene-butene copolymer, polybutene, ethylene-propylene-diene copolymer, and ethylene-vinyl acetate copolymer. Examples of the diene resin include styrene-butadiene copolymer, polybutadiene, butadiene-acrylonitrile copolymer, polyisoprene, and butene-isoprene copolymer. Examples of the acrylic resin include ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-ethyl methacrylate copolymer. As the second thermoplastic resin (D), one of these may be used alone, or two or more of these may be used in combination.

[0071] The second thermoplastic resin (D) is preferably an ethylene-propylene copolymer, an ethylene-butene copolymer, or an ethylene-propylene-diene copolymer.

[0072] The resin composition for adhesive layer according to this embodiment contains 10 to 100 parts by weight, preferably 15 to 80 parts by weight, of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide resin (A). The resin composition for adhesive layer according to this embodiment contains 10 parts by weight or more of the second thermoplastic resin (D) per 100 parts by weight of the polyphenylene sulfide-based resin (A), thereby providing excellent impact resistance at low temperatures. Furthermore, the resin composition for adhesive layers according to this embodiment contains 100 parts by weight or less of the second thermoplastic resin (D) per 100 parts by weight of the polyphenylene sulfide-based resin (A), thereby making the second thermoplastic resin (D) highly compatible with other materials.

[0073] The second thermoplastic resin (D) does not include either the polyphenylene sulfide resin (A) or the polyamide resin (B).

[0074] (additives) The resin composition for an adhesive layer according to this embodiment may further contain an additive. Examples of the additives include a crystal nucleating agent, a mold release agent, an antioxidant, a heat stabilizer, a lubricant, an ultraviolet inhibitor, a colorant, and a flame retardant.

[0075] (Method of manufacturing the resin composition for adhesive layer according to the present embodiment) As a method for producing the resin composition for adhesive layer according to this embodiment, for example, a method in which materials are supplied to a melt mixer and melt-kneaded at a temperature of 280 to 340°C can be mentioned. Examples of the melt mixer include an extruder, a Banbury mixer, a kneader, a mixing roll, etc. Examples of the extruder include a single-screw extruder and a twin-screw extruder.

[0076] From the viewpoint of increasing impact resistance, particularly impact resistance at low temperatures, by increasing the desired reactivity between the first thermoplastic resin (C) and the polyphenylene sulfide-based resin (A) or the polyamide resin (B), a two-stage extrusion method is preferred as a method for preparing the resin composition for adhesive layers according to this embodiment, in which the polyphenylene sulfide-based resin (A) portion and the polyamide resin (B) portion are extruded individually to prepare pellets of the polyphenylene sulfide-based resin (A) portion and pellets of the polyamide resin (B) portion, and the polyphenylene sulfide-based resin (A) portion and the polyamide resin (B) portion are used to alloy the polyphenylene sulfide-based resin (A) and the polyamide resin (B). From a similar viewpoint, a side feed extrusion method is also preferred as a method for preparing the resin composition for the adhesive layer according to this embodiment, in which the polyphenylene sulfide resin (A) portion is fed to the extruder from the hopper of the extruder, and the polyamide resin (B) portion is fed to the extruder from the middle of the cylinder of the extruder.

[0077] In the two-stage extrusion method, the polyphenylene sulfide-based resin (A) and the second thermoplastic resin (D) are supplied to the twin-screw extruder from a hopper of the twin-screw extruder, and are melt-kneaded at a resin temperature of 280°C to 340°C to obtain pellets of the polyphenylene sulfide-based resin (A) portion (first stage). Next, pellets of the polyphenylene sulfide resin (A) and the polyamide resin (B) are fed into the twin-screw extruder from the hopper of the twin-screw extruder, and these are melt-kneaded at a resin temperature of 280°C to 340°C to obtain the resin composition for the adhesive layer according to this embodiment (second stage). A part of the first thermoplastic resin (C) may be supplied in the first stage and the other part in the second stage. Alternatively, the entire amount of the first thermoplastic resin (C) may be supplied in the first stage. Alternatively, the entire amount of the first thermoplastic resin (C) may be supplied in the second stage. In the second step, pellets obtained by previously melt-kneading the polyamide resin (B) and the first thermoplastic resin (C) may be used.

[0078] In the side feed extrusion method, the polyphenylene sulfide resin (A) and the second thermoplastic resin (D) are fed into the twin-screw extruder from the end-loading hopper of the twin-screw extruder, and the polyamide resin (B) is fed into the twin-screw extruder from the side feeder (arranged midway in the cylinder) of the twin-screw extruder, and these are melt-kneaded at a resin temperature of 280°C to 340°C to obtain the resin composition for the adhesive layer according to this embodiment. Note that a portion of the first thermoplastic resin (C) may be fed to the twin-screw extruder from its bottom-charging hopper, and the other portion may be fed to the twin-screw extruder from its side feeder at the second stage. Alternatively, the entire amount of the first thermoplastic resin (C) may be fed to the twin-screw extruder from its bottom-charging hopper. Alternatively, the entire amount of the first thermoplastic resin (C) may be fed to the twin-screw extruder from its side feeder.

[0079] From the viewpoint of easily obtaining an excellent resin composition for an adhesive layer, a two-stage extrusion method is preferred as a method for producing the resin composition for an adhesive layer according to this embodiment. From the viewpoint of economy, the side feed extrusion method is preferred as a method for preparing the resin composition for adhesive layer according to this embodiment.

[0080] <Multilayer tube according to this embodiment> Next, the multilayer tube according to this embodiment will be described with reference to the drawings. As shown in FIG. 1, the multilayer tube X according to this embodiment is a multilayer tube in which three layers are laminated. The multilayer tube X according to this embodiment includes a first layer X1 containing a polyamide resin, a second layer X2 containing a polyphenylene sulfide resin and disposed closer to the inner circumferential surface of the multilayer tube than the first layer X1, and an adhesive layer X3 disposed between the first layer X1 and the second layer X2 and adhering the first layer X1 and the second layer X2 together.

[0081] The first layer X1 is adhered to the adhesive layer X3 without any other layer therebetween, in other words, the first layer X1 is directly adhered to the adhesive layer X3. The first layer X2 is adhered to the adhesive layer X3 without any other layer therebetween, in other words, the first layer X2 is directly adhered to the adhesive layer X3. The multilayer tube according to the present disclosure may be any multilayer tube having three or more layers laminated together, and may have, for example, a four-layer structure or a five-layer structure.

[0082] (Adhesive layer x3) The adhesive layer X3 is a layer formed from the resin composition for adhesive layer according to this embodiment.

[0083] (Second layer X2) The second layer X2 contains a polyphenylene sulfide resin. The second layer X2 is formed from a resin composition for the second layer.

[0084] The resin composition for the second layer contains a polyphenylene sulfide resin. The resin composition for the second layer preferably contains an epoxy-modified thermoplastic resin from the viewpoint of improving the melt tension of the resin composition for the second layer. The improved melt tension of the resin composition for the second layer improves the take-up property of the resin composition for the second layer when the resin composition for the second layer is molded into a tube. The improved melt tension of the resin composition for the second layer improves the draw-down property of the resin composition for the second layer when the resin composition for the second layer is blow-molded. Furthermore, the resin composition for the second layer may further contain an unmodified polyolefin resin, if necessary.

[0085] Examples of the polyphenylene sulfide-based resin in the resin composition for the second layer include the polyphenylene sulfide-based resins described above as the polyphenylene sulfide-based resin (A) in the resin composition for the adhesive layer according to this embodiment. The polyphenylene sulfide-based resin in the resin composition for the second layer may be the same as or different from the polyphenylene sulfide-based resin (A) in the resin composition for the adhesive layer according to this embodiment.

[0086] The resin composition for the second layer further contains the epoxy-modified thermoplastic resin, and preferably contains 1 to 50 parts by weight, more preferably 5 to 40 parts by weight, of the epoxy-modified thermoplastic resin per 100 parts by weight of the polyphenylene sulfide-based resin. In other words, the second layer further contains the epoxy-modified thermoplastic resin, and preferably contains 1 to 50 parts by weight, more preferably 5 to 40 parts by weight, of the epoxy-modified thermoplastic resin per 100 parts by weight of the polyphenylene sulfide-based resin. The resin composition for the second layer contains 1 part by weight or more of the epoxy-modified thermoplastic resin per 100 parts by weight of the polyphenylene sulfide-based resin, which makes it easier for the second layer to exhibit the impact resistance improving effect. The resin composition for the second layer contains 50 parts by weight or less of the epoxy-modified thermoplastic resin per 100 parts by weight of the polyphenylene sulfide-based resin, so that the polyphenylene sulfide-based resin and the epoxy-modified thermoplastic resin are less likely to gel when they are melt-kneaded, and are therefore easier to melt-knead.

[0087] Examples of the epoxy-modified thermoplastic resin include olefin copolymers having epoxy groups in the side chains or main chains. Examples of the olefin copolymer having an epoxy group include an olefin copolymer having a glycidyl group. Examples of the olefin copolymer having a glycidyl group include a glycidyl ester type olefin copolymer, a glycidyl ether type olefin copolymer, and a glycidyl amine type olefin copolymer. Furthermore, as the olefin copolymer having a glycidyl group, a copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated acid is preferred. Examples of the α-olefin include ethylene, propylene, and butene-1. The glycidyl ester of an α,β-unsaturated acid is a compound represented by the following formula (9).

[0088] [ka]

[0089] In the above formula (9), R represents any one selected from a hydrogen atom and an alkyl group having 1 to 6 carbon atoms.

[0090] Examples of the glycidyl ester of an α,β-unsaturated acid include glycidyl acrylate, glycidyl methacrylate, and glycidyl ethacrylate, with glycidyl methacrylate being particularly preferred. The copolymer of an α-olefin and a glycidyl ester of an α,β-unsaturated acid may be any of a random copolymer, a block copolymer, and a graft copolymer.

[0091] Further, examples of the olefin copolymer having an epoxy group in the side chain or main chain include those obtained by subjecting the double bond of a double bond-containing olefin copolymer to epoxy oxidation.

[0092] Examples of the unmodified polyolefin resin include polyethylene (e.g., high-density polyethylene, medium-density polyethylene, low-density polyethylene, etc.), polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, polybutene, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, etc. The unmodified polyolefin resin may be a diene resin, a hydrogenated diene resin, an acrylic resin, or the like. Examples of the diene resin include styrene-butadiene copolymer, polybutadiene, butadiene-acrylonitrile copolymer, and polyisoprene butene-isoprene copolymer. Examples of the acrylic resin include ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-isopropyl acrylate copolymer, ethylene-methyl methacrylate copolymer, and ethylene-methyl methacrylate copolymer.

[0093] The second layer X2 containing a polyphenylene sulfide resin is disposed closer to the inner circumferential surface of the multilayer tube than the first layer X1. Therefore, when a chemical is circulated through the multilayer tube of this embodiment, the multilayer tube X has excellent chemical resistance to the chemical.

[0094] The second layer X2 contains a larger amount of polyphenylene sulfide resin than the adhesive layer X3.

[0095] (Method for producing resin composition for second layer) The resin composition for the second layer can be produced, for example, by supplying the materials to a melt mixer and melt-kneading them at a temperature of 280 to 340°C. Examples of the melt mixer include an extruder, a Banbury mixer, a kneader, a mixing roll, etc. Examples of the extruder include a single-screw extruder and a twin-screw extruder. From the viewpoint of increasing the reactivity between the polyphenylene sulfide resin and the epoxy-modified thermoplastic resin, it is preferable to use a twin-screw extruder as the extruder.

[0096] (First layer X1) The first layer X1 contains a polyamide resin. The first layer X1 is formed from a resin composition for a first layer.

[0097] The resin composition for the first layer contains a polyamide resin. Furthermore, the resin composition for the first layer may contain at least one of other thermoplastic resins, plasticizers, and stabilizers, if necessary.

[0098] Examples of the polyamide resin in the first layer X1 include the polyamide resins described above as the polyamide resin (B) in the resin composition for adhesive layer according to this embodiment. The polyamide resin in the first layer X1 may be the same as or different from the polyamide resin (B) in the resin composition for an adhesive layer according to this embodiment. The polyamide resin contained in the first layer X1 preferably contains at least one of polyamide 11 and polyamide 12 from the viewpoints of dimensional stability, chemical resistance, impact resistance, and the like.

[0099] The first layer X1 contains more polyamide resin than the adhesive layer X3.

[0100] (Method for producing resin composition for first layer) The resin composition for the first layer can be produced, for example, by supplying materials to a melt mixer and melt-kneading them at a temperature of 180 to 300°C. Examples of the melt mixer include an extruder, a Banbury mixer, a kneader, a mixing roll, etc. Examples of the extruder include a single-screw extruder and a twin-screw extruder.

[0101] The flexural modulus of the multilayer tube according to this embodiment is preferably 2.0 GPa or less from the viewpoints of excellent flexibility and excellent workability in bending. The flexural modulus of the multilayer tube according to this embodiment is a value measured by molding a Type A1 test piece defined in ISO 20753 from each resin composition and conducting a flexural test in accordance with ISO 178. Furthermore, by melt-kneading the resin composition for the adhesive layer according to this embodiment using a twin-screw extruder, the dispersibility of the first thermoplastic resin (C) can be improved, and as a result, the flexural modulus of the multilayer tube according to this embodiment can be increased.

[0102] (Manufacturing method of multilayer tube) The multilayer tube according to this embodiment can be produced by a co-extrusion method. In the method for producing a multilayer tube according to this embodiment, first, the resin composition for the adhesive layer, the resin composition for the first layer, and the resin composition for the second layer are supplied to separate extruders to obtain respective molten resins. Then, by extruding each molten resin from each extruder into a single die, the molten resins are merged within the die, and the molten resins are further co-extruded out of the die, thereby obtaining the multilayer tube according to this embodiment. The multilayer tube according to this embodiment can be obtained by a known tube molding method, blow molding method, or the like.

[0103] (Applications of multi-layer tubes) The multilayer tube according to this embodiment has excellent heat resistance, hot water resistance, chemical resistance, gas permeability resistance, flexibility, and the like. The multi-layer tube according to this embodiment can be used as a tube for transporting, for example, fuel (for example, gasoline), water (for example, cooling water), chemicals, and the like. The multilayer tube according to this embodiment can also be used as an electric component, an electronic component, or the like.

[0104] [Disclosure items] Each of the following sections is a disclosure of a preferred embodiment.

[0105] [Item 1] A polyphenylene sulfide resin (A), a polyamide resin (B); a first thermoplastic resin (C) having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate salt, and a carboxylate ester; and a second thermoplastic resin (D) having no epoxy group, acid anhydride group, carboxyl group, carboxylate salt, or carboxylate ester, The composition contains 80 to 300 parts by weight of the polyamide resin (B), 20 to 200 parts by weight of the first thermoplastic resin (C), and 10 to 100 parts by weight of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide-based resin (A), The resin composition for an adhesive layer, wherein the polyamide resin (B) has a terminal amino group concentration of 48 to 120 mmol / kg.

[0106] [Item 2] Item 2. The resin composition for an adhesive layer according to item 1, wherein the polyamide resin (B) has a melt mass flow rate at 230° C. of 1 to 50 g / 10 min.

[0107] [Item 3] 3. The resin composition for an adhesive layer according to item 1 or 2, wherein the polyamide resin (B) contains at least one of polyamide 11 and polyamide 12.

[0108] [Item 4] It has a matrix-domain structure comprising a matrix and a domain, The polyamide resin (B) is contained in the matrix, 4. The adhesive layer resin composition according to any one of items 1 to 3, wherein the polyphenylene sulfide resin (A) is contained in the domain.

[0109] [Item 5] A multi-layer tube in which three or more layers are laminated, a first layer containing a polyamide resin; a second layer that is disposed closer to an inner circumferential surface of the multilayer tube than the first layer and contains a polyphenylene sulfide resin; an adhesive layer disposed between the first layer and the second layer and adhering the first layer to the second layer; A multilayer tube, wherein the adhesive layer is formed from the resin composition for adhesive layer according to any one of items 1 to 4.

[0110] [Item 6] Item 6. The multilayer tube according to item 5, wherein the polyamide resin in the first layer includes at least one of polyamide 11 and polyamide 12.

[0111] [Item 7] 7. The multilayer tube according to item 5 or 6, wherein the second layer further contains an epoxy-modified thermoplastic resin in an amount of 1 to 50 parts by weight per 100 parts by weight of the polyphenylene sulfide resin. [Example]

[0112] Next, the present disclosure will be described in more detail with reference to examples and comparative examples, but the present disclosure is not limited to these examples in any way.

[0113] [Resin composition for adhesive layer] First, to prepare the resin compositions for adhesive layers of the examples and comparative examples, the following materials were prepared: polyphenylene sulfide resin (A), polyamide resin (B), first thermoplastic resin (C), second thermoplastic resin (D), and antioxidant (F).

[0114] <Polyphenylene sulfide resin (A)> (Polyphenylene sulfide resin (A-1)) A first autoclave was prepared, which had a first reaction vessel, a first stirrer for stirring the contents in the first reaction vessel, and a bottom stop valve for opening and closing the first reaction vessel. Next, 8.27 kg of 47.5 wt % sodium hydrosulfide (sodium hydrosulfide: 70.00 mol), 2.91 kg of 96 wt % sodium hydroxide (sodium hydroxide: 69.80 mol), 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 2.24 kg (27.3 mol) of sodium acetate, and 10.5 kg of ion-exchanged water were placed in the first reaction vessel. Then, while nitrogen gas was being passed into the first reaction vessel at normal pressure, the first reaction vessel was gradually heated over a period of about 3 hours until the temperature of the contents in the first reaction vessel reached 245° C. As a result, 14.78 kg of water and 0.28 kg of N-methyl-2-pyrrolidone (NMP) were distilled from the first reaction vessel. The contents of the first reaction vessel were then cooled to 200°C. The amount of water remaining in the first reaction vessel (including water consumed by the hydrolysis of N-methyl-2-pyrrolidone (NMP)) per mole of alkali metal sulfide (sodium hydrosulfide) placed in the first reaction vessel was 1.06 moles. The amount of hydrogen sulfide discharged out of the first reaction vessel was 0.02 moles per mole of alkali metal sulfide (sodium hydrosulfide) placed in the first reaction vessel. Next, 10.34 kg (70.32 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were placed in the first reaction vessel, and the first reaction vessel was sealed under nitrogen gas. Next, while the content in the first reaction vessel was stirred at 240 rpm by a first stirrer, the content in the first reaction vessel was heated from 200°C to 235°C at a rate of 0.8°C / min. The contents in the first reaction vessel were then reacted by heating the contents at 235° C. for 40 minutes while stirring the contents with a first stirrer at 240 rpm. Thereafter, the contents were heated from 235°C to 270°C at a rate of 0.8°C / min while being stirred with a stirrer at 240 rpm. The contents were then reacted by heating the contents at 270° C. for 70 minutes while stirring the contents with a stirrer at 240 rpm. Then, while stirring the contents in the first reaction vessel with the first stirrer, the inside of the first reaction vessel was pressurized with nitrogen gas for 15 minutes with the bottom plug valve open, thereby performing flash distillation. Thereafter, the content in the first reaction vessel was stirred for a while with a stirrer at 250° C. As a result, most of the N-methyl-2-pyrrolidone (NMP) was removed from the content in the first reaction vessel, and a first solid was obtained.

[0115] A second autoclave was prepared, which had a second reaction vessel and a second agitator for agitating the contents of the second reaction vessel. Next, the first solid material and 76 liters of ion-exchanged water were placed in the second reaction vessel. The content in the second reaction vessel was then stirred with a second stirrer at 70° C. for 30 minutes, thereby washing the first solid matter with ion-exchanged water. Thereafter, the content in the second reaction vessel was subjected to suction filtration using a glass filter to obtain a second solid matter. Next, 76 liters of ion-exchanged water at 70° C. was poured onto the second solid on the glass filter, and the second solid and the ion-exchanged water were filtered under suction to obtain a third solid.

[0116] A third autoclave was prepared, which had a third reaction vessel and a second agitator for agitating the contents in the third reaction vessel. Next, the third solid material and 90 liters of ion-exchanged water were placed in the third reaction vessel. Then, the air in the third reaction vessel was replaced with nitrogen gas. The contents of the third reaction vessel were then heated to 192°C and the contents were heated at 192°C for 30 minutes. The third reaction vessel was then cooled and the contents of the third reaction vessel were removed. The contents were then suction filtered through a glass filter to obtain a fourth solid. Thereafter, 76 liters of ion-exchanged water at 70° C. was poured onto the fourth solid on the glass filter, and the fourth solid and the ion-exchanged water were suction filtered to obtain a fifth solid. The fifth solid was dried at 120° C. under a nitrogen gas stream to obtain a polyphenylene sulfide resin (A-1).

[0117] The melt mass flow rate (MFR) of the polyphenylene sulfide resin (A-1) at 315.5°C was 230 g / 10 min. The melt mass flow rate (MFR) of the polyphenylene sulfide resin (A-1) at 315.5° C. was measured by the method described above.

[0118] <Polyamide resin (B)> B-1: Polyamide 12 (manufactured by Daicel-Evonik) (terminal amino group concentration: 52 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 2.74, melt mass-flow rate (MFR) (temperature: 230°C, load: 2,160 kg): 3 g / 10 min) B-2: Polyamide 12 (manufactured by Daicel-Evonik) (terminal amino group concentration: 64 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 3.37, melt mass-flow rate (MFR) (temperature: 230°C, load: 2,160 kg): 8 g / 10 min) B-3: Polyamide 12 (manufactured by Daicel-Evonik) (terminal amino group concentration: 5 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 0.07, melt mass-flow rate (MFR) (temperature: 230°C, load: 2,160 kg): 8 g / 10 min) B-4: Polyamide 12 (Arkema, trade name: Lilusamide, model number: AESNOTL) (terminal amino group concentration: 29 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 0.78, melt mass-flow rate (MFR) (temperature: 230°C, load: 2,160 kg): 5 g / 10 min)

[0119] The terminal amino group concentration, terminal amino group concentration / terminal carboxyl group concentration, and melt mass flow rate (MFR) of the polyamide resin (B) were measured by the methods described above.

[0120] Furthermore, the terminal amino group concentration and terminal amino group concentration / terminal carboxyl group concentration were measured for the following polyamide resins. B-5: Polyamide 11 (manufactured by Arkema, trade name: Rilsan, model number: BESNOTL) (terminal amino group concentration: 38 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 0.38) B-6: Polyamide 6 (Toray Industries, Inc., "Amilan") (terminal amino group concentration: 46 mmol / kg, terminal amino group concentration / terminal carboxyl group concentration: 0.82) Therefore, the polyamides used in the examples of JP-A-2008-213458 (B-4 to B-6 of the present application) (B-1 to B-3 of JP-A-2008-213458) had a terminal amino group concentration of 46 mmol / kg or less.

[0121] <First Thermoplastic Resin (C) Having at Least One Functional Group Selected from Epoxy Group, Acid Anhydride Group, Carboxyl Group, Carboxylate, and Carboxylate Ester> C-1: Copolymer of ethylene and glycidyl methacrylate (Sumitomo Chemical Co., Ltd., "Bondfast" E) C-2: Acid-modified ethylene and 1-butene copolymer (Mitsui Chemicals, "Tafmer" MH5020)

[0122] <Second Thermoplastic Resin (D) Having No Epoxy Group, Acid Anhydride Group, Carboxyl Group, Carboxylate Salt, or Carboxylate Ester> D-1: Ethylene-1-butene copolymer (Mitsui Chemicals, "Tafmer" A4085S)

[0123] <Antioxidant (F)> F-1: Tetrakis-[methylene-3-(3',5'-di-t-butyl-4-hydroxyphenyl)propionate]methane

[0124] (Examples 1-1 and 1-2, and Comparative Examples 1-1 to 1-4) Pellets of the resin composition for adhesive layers were obtained by a two-stage extrusion method. First, in the first step, the materials for the first step shown in Table 1 below were dry blended and premixed in a tumbler for 2 minutes to obtain a first premixture. Next, the first preliminary mixture was melt-kneaded in a twin-screw extruder (cylinder temperature setting: between 280°C and 320°C) to obtain first pellets. Then, for the second step, the materials for the second step shown in Table 1 below were dry blended with the first pellets, and premixed in a tumbler for 2 minutes to obtain a second premixture. Thereafter, the second preliminary mixture was melt-kneaded in a twin-screw extruder (cylinder temperature setting: between 280°C and 320°C) to obtain pellets of a resin composition for adhesive layer.

[0125] (Example 1-3: Dry blending in one go) The materials shown in Table 1 below were dry blended together and premixed in a tumbler for 2 minutes to obtain a premix. Next, the preliminary mixture was melt-kneaded in a twin-screw extruder (cylinder temperature setting: between 280°C and 320°C) to obtain pellets of a resin composition for adhesive layer.

[0126] (Melt mass flow rate (MFR) of adhesive layer resin composition) The melt mass flow rate (MFR) of the resin composition for the adhesive layer at 315.5°C was measured by the method described in ASTM-D1238-70. In addition, the melt mass flow rate (MFR) of the resin composition for the adhesive layer at 315.5°C was measured by drying 5 g of pellets of the resin composition for the adhesive layer, heating the dried pellets of the resin composition for the adhesive layer (A) at 315.5°C for 5 minutes, and then applying a load of 5,000 g to the heated pellets of the resin composition for the adhesive layer. The measured values ​​are shown in Table 1 below.

[0127] (Terminal Amino Group Concentration and Terminal Amino Group Concentration / Terminal Carboxyl Group Concentration in Adhesive Layer Resin Composition) The terminal amino group concentration and terminal carboxyl group concentration in the resin composition for adhesive layer were measured, and the terminal amino group concentration / terminal carboxyl group concentration in the resin composition for adhesive layer was calculated. The terminal amino group concentration in the resin composition for adhesive layer was determined as follows. First, a phenol / ethanol solvent was prepared by mixing phenol and ethanol in a volume ratio of 9:1. Next, the weighed resin composition for adhesive layers was dissolved in 40 mL of a phenol / ethanol solvent to obtain a first solution. Then, 10 mL of ethanol was added to the first solution to obtain a second solution. Next, the second solution was titrated with an N / 100 aqueous hydrochloric acid solution to determine the terminal amino group concentration of the resin composition for adhesive layer. The terminal carboxyl group concentration in the resin composition for adhesive layer was determined as follows. First, a weighed resin composition for adhesive layers was dissolved in 50 mL of benzyl alcohol in an oil bath at 180° C. to obtain a solution. Next, the solution was titrated with a N / 100 potassium hydroxide-ethanol solution using phenolphthalein as an indicator to determine the terminal carboxyl group concentration of the resin composition for adhesive layer. The terminal amino group concentration and the terminal amino group concentration / terminal carboxyl group concentration in the resin composition for adhesive layer are shown in Table 1 below.

[0128] (Preparation of test specimens) Using a hot air dryer, pellets of the resin compositions for adhesive layers of the Examples and Comparative Examples were dried at 130° C. for 3 hours. Next, the dried pellets of the resin composition for the adhesive layer were fed into a Sumitomo Heavy Industries injection molding machine (SE-50D) (cylinder temperature: 320°C, mold temperature: 145°C), and the pellets of the resin composition for the adhesive layer were injection molded using a mold with a Type A1 test piece shape specified in ISO 20753 to obtain test pieces. Injection molding was performed under conditions where the average speed of the molten resin was 400±50 mm / s, and dumbbell-shaped test pieces were obtained. In Comparative Example 1, air bubbles were trapped in the molten resin during injection molding, and it was not possible to obtain the dumbbell-shaped test piece. The results are shown in Table 1 below.

[0129] (Tensile strength and tensile elongation) The test pieces were used to measure the tensile strength and tensile elongation of the resin composition for adhesive layer in accordance with ISO527-1 and -2. Specifically, the test piece was conditioned by placing it at a temperature of 23°C and a relative humidity of 50% for 16 hours. Then, using the conditioned test piece, the flexural modulus of the adhesive layer resin composition was measured under the following conditions in accordance with ISO527-1 and -2. Measurement environment temperature: 23°C Relative humidity of measurement environment: 50% Grip distance: 114 mm Test speed: 50 mm / s The results are shown in Table 1 below.

[0130] (flexural modulus) The flexural modulus of the resin composition for adhesive layer was measured in accordance with ISO 178 using the test piece. Specifically, a Type B2 test piece was obtained by cutting out the center of the test piece. The Type B2 test piece was then conditioned by placing it at a temperature of 23°C and a relative humidity of 50% for 16 hours. The flexural modulus of the adhesive layer resin composition was measured using the conditioned Type B2 test piece in accordance with ISO 178 under the following conditions: Measurement environment temperature: 23°C Relative humidity of measurement environment: 50% Span: 64mm, Test speed: 2 mm / s The results are shown in Table 1 below.

[0131] (Charpy impact strength (notched)) The Charpy impact strength (notched) of the resin composition for adhesive layer was measured using the test piece in accordance with ISO 179-1. Specifically, a notched test piece (length: 80 mm, notch width: 4 mm) was obtained by cutting out the center of the test piece and forming a notch. The notched test piece was then conditioned by placing it at a temperature of 23°C and a relative humidity of 50% for 16 hours. The conditioned notched test piece was then used to measure the Charpy impact strength (notched) of the adhesive layer resin composition according to ISO 179-1 under the following conditions. Measurement environment temperature: 23°C Relative humidity of measurement environment: 50% The results are shown in Table 1 below.

[0132] [Table 1]

[0133] Unlike Comparative Example 1-1, test pieces could be obtained in Examples 1-1 to 1-3. It is presumed that test pieces could be obtained in Examples 1-1 to 1-3 because the MFR was low. As shown in Table 1 above, Examples 1-1 to 1-3 had higher flexural modulus than Comparative Examples 1-2 and 1-3. Note that in Comparative Example 1-1, a test piece could not be obtained, and therefore the flexural modulus could not be measured. In Example 1-1 using the two-stage extrusion method, the tensile elongation and Charpy impact strength were higher than those in Example 1-3 in which the materials were kneaded all at once.

[0134] [Multi-layer tube] To produce the multilayer tubes of the Examples and Comparative Examples, in addition to pellets of the resin compositions for the adhesive layer of Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-4, pellets of the resin composition for the first layer described below and the resin composition for the second layer described below were prepared as materials.

[0135] <Resin composition for first layer> As the resin composition for the first layer, unplasticized high-viscosity polyamide 12 (manufactured by Daicel-Evonik Co., Ltd., "Vestamid" LX9008 Black) was prepared.

[0136] <Resin composition for second layer> To prepare a resin composition for the second layer, the following materials were prepared.

[0137] (Polyphenylene sulfide resin) An autoclave was prepared, which had a reaction vessel, a stirrer for stirring the contents in the reaction vessel, and a bottom plug valve for opening and closing the first reaction vessel. Next, 8.27 kg of 47.5 wt % sodium hydrosulfide (sodium hydrosulfide: 70.00 mol), 2.94 kg of 96 wt % sodium hydroxide (sodium hydroxide: 70.63 mol), 11.45 kg (115.50 mol) of N-methyl-2-pyrrolidone (NMP), 1.89 kg (23.1 mol) of sodium acetate, and 5.50 kg of ion-exchanged water were placed in the reaction vessel. Then, while nitrogen gas was passed through the reaction vessel at normal pressure, the reaction vessel was gradually heated over approximately 3 hours until the temperature of the contents in the reaction vessel reached 245° C. As a result, 9.77 kg of water and 0.28 kg of N-methyl-2-pyrrolidone (NMP) were distilled from the reaction vessel. The contents of the reaction vessel were then cooled to 200°C. The amount of water remaining in the reaction vessel (including water consumed by the hydrolysis of N-methyl-2-pyrrolidone (NMP)) per mole of alkali metal sulfide (sodium hydrosulfide) placed in the reaction vessel was 1.06 moles. The amount of hydrogen sulfide discharged out of the reaction vessel was 0.02 moles per mole of alkali metal sulfide (sodium hydrosulfide) placed in the reaction vessel. Next, 10.42 kg (70.86 mol) of p-dichlorobenzene and 9.37 kg (94.50 mol) of NMP were placed in the reaction vessel, and the reaction vessel was sealed under nitrogen gas. Next, the temperature of the content in the reaction vessel was increased from 200° C. to 270° C. at a rate of 0.6° C. / min while stirring the content in the reaction vessel with a stirrer at 240 rpm. The contents in the reaction vessel were then reacted by heating the contents at 270° C. for 140 minutes while stirring the contents with a stirrer at 240 rpm. Thereafter, the content of the reaction vessel was cooled from 270° C. to 250° C. over 15 minutes, while 2.40 kg (133 mol) of water was injected into the reaction vessel. The contents of the reaction vessel were then cooled from 250° C. to 220° C. over 75 minutes. The contents in the reaction vessel were then rapidly cooled from 220° C. to near room temperature, and the contents were removed. Thereafter, the contents were diluted with approximately 35 liters of N-methyl-2-pyrrolidone (NMP) to obtain a first slurry, and the first slurry was stirred at 85°C for 30 minutes. The first slurry was then filtered through an 80-mesh wire screen (openings: 0.175 mm) to obtain a first solid matter. Next, the first solid was diluted with approximately 35 liters of N-methyl-2-pyrrolidone (NMP) to obtain a second slurry, and the second slurry was stirred at 85°C for 30 minutes. The second slurry was then filtered through an 80-mesh wire screen to obtain a second solid. The second solid was diluted with 70 liters of ion-exchanged water to obtain a third slurry, which was stirred at 70°C for 30 minutes and filtered through an 80-mesh wire screen (washed with ion-exchanged water). The washing with ion-exchanged water was further repeated two times to obtain a third solid. The third solid was diluted with 32 g of acetic acid and 70 L of ion-exchanged water to obtain a fourth slurry, which was stirred at 70°C for 30 minutes and filtered through an 80-mesh wire mesh to obtain a fourth solid. The fourth solid was diluted with 70 liters of ion-exchanged water to obtain a fifth slurry, which was stirred at 70°C for 30 minutes and filtered through an 80-mesh wire mesh to obtain a fifth solid. The fifth solid was dried at 120° C. under a nitrogen gas flow to obtain a polyphenylene sulfide resin.

[0138] The melt mass flow rate (MFR) of the polyphenylene sulfide resin at 315.5°C was 300 g / 10 min. The melt mass flow rate (MFR) of the polyphenylene sulfide resin at 315.5°C was measured by the method described above.

[0139] (Epoxy modified thermoplastic resin) As the epoxy-modified thermoplastic resin, a copolymer of ethylene and glycidyl methacrylate was prepared.

[0140] (others) Other materials used were a copolymer of ethylene and 1-butene and high density polyethylene.

[0141] The polyphenylene sulfide resin, the copolymer of ethylene and glycidyl methacrylate, the copolymer of ethylene and 1-butene, and the high-density polyethylene were dry blended and premixed in a tumbler for 2 minutes to obtain a premixture. Next, the preliminary mixture was melt-kneaded in a twin-screw extruder (cylinder temperature setting: between 280°C and 320°C) and pelletized with a strand cutter to obtain pellets of a resin composition for the second layer. The resin composition for the second layer contained 15 parts by weight of the copolymer of ethylene and glycidyl methacrylate, 15 parts by weight of the copolymer of ethylene and 1-butene, and 5 parts by weight of high-density polyethylene, relative to 100 parts by weight of the polyphenylene sulfide resin.

[0142] The resin composition for the second layer had a flexural modulus of 1.8 GPa. The flexural modulus of the resin composition for the second layer was measured in the same manner as the flexural modulus of the resin composition for the adhesive layer.

[0143] (Examples 2-1 and 2-2, and Comparative Examples 2-1 to 2-4) The resin composition for the first layer was fed into a 50 mm outer layer extruder (temperature controlled at 260°C), pellets of the resin compositions for the adhesive layer of Examples 1-1, 1-2, and Comparative Examples 1-1 to 1-4 were fed into a 25 mm adhesive layer extruder (temperature controlled at 320°C), and pellets of the composition for the second layer were fed into a 40 mm inner layer extruder (temperature controlled at 310°C). Next, each resin composition was melt-kneaded inside each extruder, and each resin composition was supplied from each extruder to a co-extrusion die (temperature controlled at 290°C). Each resin composition was melt-bonded in a multi-layer manner at the joint inside the co-extrusion die, and each resin composition was co-extruded as a three-layer parison from the die face at the tip of the co-extrusion die. The discharge pressure of the resin composition for adhesive layer during co-extrusion was measured and is shown in Table 2 below. The three-layer parison was cooled and solidified in a sizing device to obtain a three-layer tube (outer diameter: 8 mm, inner diameter: 6 mm). The take-up speed of the three-layer parison was 15 m / min. The three-layer tube had a three-layer structure consisting of an outer layer, an inner layer located closer to the inner periphery than the outer layer, and an adhesive layer disposed between the outer layer and the inner layer. The outer layer was formed from the resin composition for the first layer and had a thickness of about 0.7 mm. The inner layer was formed from the resin composition for the second layer and had a thickness of about 0.2 mm. The adhesive layer was formed from a resin composition for adhesive layers and had a thickness of about 0.1 mm. The three-layer tubes of Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-4 were formed using pellets of the resin compositions for adhesive layers of Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-4, respectively.

[0144] (Domain diameter) The three-layer tubes of the examples and comparative examples were cut perpendicular to the longitudinal direction. Next, the cross section of the three-layer tube was photographed with a scanning electron microscope (SEM), and the domain diameter in the image (magnification: 1000 times) was observed and evaluated according to the following criteria. ○: When the domain diameter is 50 μm or less △: Domain diameter is more than 50 μm and 200 μm or less ×: When the domain diameter exceeds 200 μm The results are shown in Table 2 below.

[0145] (Tensile test) The three-layer tubes of the examples and comparative examples were subjected to a tensile test in accordance with SAE J2260 under the following conditions. Environmental temperature: 23℃ Ambient relative humidity: 50% The results are shown in Table 2 below.

[0146] (Adhesion strength test) The three-layer tubes of the examples and comparative examples were cut to obtain strip-shaped test pieces (width: 5 mm, length: 110 mm or more). Next, an attempt was made to preliminarily peel off about 30 mm from the tip of the test piece with a cutter, but preliminarily peeling was not possible for either the three-layer tube of the Example or Comparative Example, and the test did not proceed to the adhesive strength test. The results are shown in Table 2 below.

[0147] (Low temperature impact test) (DIN 73378) The three-layer tubes of the examples and comparative examples were subjected to a Charpy impact test (n=10) under the following conditions in accordance with DIN 73378. The number of broken tubes out of the 10 tubes was counted. Speed: 3.8m / sec Work load: 7.5J Temperature: -40℃ The results are shown in Table 2 below.

[0148] (SAE J2260) The three-layer tubes of the examples and comparative examples were subjected to an impact test (n=10) in accordance with SAE J2260 under the following conditions. The number of broken tubes out of the 10 tubes was counted. Hammer weight: 912g Hammer tip diameter: 15.88 mm Drop height: 305mm Temperature: -40℃ The results are shown in Table 2 below.

[0149] (SAE J844) The three-layer tubes of the examples and comparative examples were subjected to an impact test (n=10) in accordance with SAE J844 under the following conditions: The number of broken three-layer tubes out of ten three-layer tubes was counted. Hammer weight: 454g Hammer tip diameter: 15.88 mm Drop height: 305mm Temperature: -40℃ The results are shown in Table 2 below.

[0150] [Table 2]

[0151] As shown in Table 2 above, all of the three-layer tubes of the examples and comparative examples showed good results in the tensile test, adhesive strength test, and low-temperature impact test. Furthermore, as shown in Table 2 above, the domain diameter was smaller in the example than in the comparative examples 2-1, 2-3, and 2-4. Furthermore, as shown in Table 2 above, in the examples, the discharge pressure during co-extrusion molding was higher and molding was easier than in comparative examples 2-1, 2-3, and 2-4.

[0152] (Thickness variation in adhesive layer) The three-layer tubes of the examples and comparative examples were cut perpendicular to the longitudinal direction. Next, the cross section of the three-layered tube was photographed using an optical microscope, and the thickness of the adhesive layer was measured at 10 or more points. Then, "(maximum thickness of adhesive layer - minimum thickness of adhesive layer) / arithmetic mean value of thickness of adhesive layer" was defined as "variation in thickness of adhesive layer." The results are shown in Table 3 below.

[0153] [Table 3]

[0154] As shown in Table 3 above, in the examples within the scope of the present disclosure, the variation in the thickness of the adhesive layer, i.e., "(maximum thickness in adhesive layer - minimum thickness in adhesive layer) / arithmetic mean thickness in adhesive layer," was smaller than in the comparative examples in which the terminal amino group concentration of the polyamide resin in the resin composition for the adhesive layer was 46 mmol / kg or less. Therefore, according to the present disclosure, a resin composition for an adhesive layer is provided that can easily suppress variations in the thickness of an adhesive layer when the adhesive layer is formed from the resin composition for an adhesive layer by melt extrusion molding. [Explanation of symbols]

[0155] X: multilayer tube, X1: first layer, X2: second layer, X3: adhesive layer

Claims

1. A polyphenylene sulfide-based resin (A), a polyamide resin (B); a first thermoplastic resin (C) having at least one functional group selected from an epoxy group, an acid anhydride group, a carboxyl group, a carboxylate salt, and a carboxylate ester; and a second thermoplastic resin (D) having no epoxy group, acid anhydride group, carboxyl group, carboxylate salt, or carboxylate ester, The composition contains 80 to 300 parts by weight of the polyamide resin (B), 20 to 200 parts by weight of the first thermoplastic resin (C), and 10 to 100 parts by weight of the second thermoplastic resin (D) relative to 100 parts by weight of the polyphenylene sulfide-based resin (A), the polyamide resin (B) has a terminal amino group concentration of 48 to 120 mmol / kg; the first thermoplastic resin (C) is a polyolefin copolymer, A resin composition for an adhesive layer, wherein the second thermoplastic resin (D) is a polyolefin-based resin.

2. 2. The resin composition for an adhesive layer according to claim 1, wherein the polyamide resin (B) has a melt mass flow rate at 230° C. of 1 to 50 g / 10 min.

3. 3. The resin composition for an adhesive layer according to claim 1, wherein the polyamide resin (B) comprises at least one of polyamide 11 and polyamide 12.

4. It has a matrix-domain structure comprising a matrix and a domain, the polyamide resin (B) is contained in the matrix, The resin composition for an adhesive layer according to claim 1 or 2, wherein the polyphenylene sulfide-based resin (A) is contained in the domain.

5. A multi-layer tube in which three or more layers are laminated, a first layer containing a polyamide resin; a second layer that is disposed closer to an inner peripheral surface of the multilayer tube than the first layer and contains a polyphenylene sulfide-based resin; an adhesive layer disposed between the first layer and the second layer and adhering the first layer to the second layer; A multilayer tube, wherein the adhesive layer is formed from the resin composition for adhesive layers according to claim 1 or 2.

6. 6. The multi-layer tube according to claim 5, wherein the polyamide resin in the first layer includes at least one of polyamide 11 and polyamide 12.

7. 6. The multilayer tube according to claim 5, wherein the second layer further contains an epoxy-modified thermoplastic resin in an amount of 1 to 50 parts by weight per 100 parts by weight of the polyphenylene sulfide-based resin.

Images