Polyamide resin composition, molded article obtained by molding the same, and method for producing the same

Abstract

The present invention provides a polyamide resin composition, a molded article thereof, and a method for producing the same. The polyamide resin composition comprises 0.01 to 12 parts by weight of a silicone resin (B) and 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, relative to 100 parts by weight of a polyamide resin (A). Even in polyamide resin compositions containing silicone resin as an impurity, the silicone resin can be prevented from falling out of molded articles formed by injection molding the polyamide resin composition and from adhering to the mold surface during molding. Furthermore, the molded articles exhibit excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to a polyamide resin composition formed by blending a polyamide resin, a silicone resin, and a silane coupling agent having a specific functional group, and a molded article obtained by molding the polyamide resin composition. Furthermore, the present invention relates to a method for producing a polyamide resin composition suitable for recovering material from a polyamide resin composite having a silicone resin layer formed on the surface of a polyamide resin molded article, and a method for producing a molded article obtained by molding the polyamide resin composition obtained by the production method. Background Art

[0002] Polyamide resins have long been used as industrial materials, for example, in the form of fibers, films, and resin molded products. Among them, polyamide 6 and polyamide 66 are used in a wide range of fields, including automotive parts and office automation equipment.

[0003] As the use of polyamide resins increases, the problem of large amounts of waste has also surfaced. Therefore, methods for recycling discarded polyamide resin molded products have been widely studied.

[0004] Generally, there are three main recycling methods for plastic products such as polyamide resins. These include thermal recovery, which extracts heat energy by incinerating the plastic products; chemical recovery, which chemically decomposes the plastic products into their raw monomers and then repolymerizes them; and material recovery, which melts the plastic products and reshapes them into new products.

[0005] In today's world where the depletion of petroleum, a raw material for polyamide resins, has become a major concern, chemical recycling and material recovery are preferred from the perspective of resource reuse among the aforementioned recovery methods. Furthermore, material recovery is more preferred from the perspective of more efficient energy reduction, compared to chemical recovery, which consumes a large amount of energy when breaking down polymers into monomers for recycling.

[0006] When recycling materials, it is necessary to improve the purity of the plastic products used as the materials in order to maintain the high quality of the appearance and various properties of the recycled products.

[0007] However, polyamide resin products are often mixed with various additives, surface-treated, or have other resin components formed on their surfaces. Therefore, it is not easy to extract polyamide resin with fewer impurities from polyamide resin products and recycle them.

[0008] The following methods are known for recovering polyamide resin molded articles with layers of other resin components formed on their surfaces. Specifically, a method has been proposed for removing the silicone resin layer from the surface of scrap fabric from airbags using polyamide resins or the like as base fabric by immersing the scrap fabric in an alkaline solution, followed by dehydration and stirring within a container. Another method has been proposed for removing impurities by heating a polyamide 6 product containing one or more resin components as impurities in an alkaline aqueous solution or an organic solvent.

[0009] However, these methods make it difficult to completely separate the silicone resin layer formed on the surface of a polyamide resin molded article. When a polyamide resin molded article from which the silicone resin layer has not been completely separated is recycled, there are problems such as the silicone resin easily falling off from a molded article injection-molded using the recycled resin composition as a raw material, and the silicone resin adhering to the surface of the injection mold during molding. Furthermore, there is the problem of reduced mechanical properties of the molded article. To address these issues, the polyamide resin compositions disclosed in Patent Documents 1 and 2 have been proposed.

[0010] Patent Document 1 discloses a polyamide resin composition containing a polyamide resin and a specific amount of a silicone resin, and a polyamide resin composition containing a metal behenate as a higher fatty acid metal salt, and discloses improved mechanical properties and handleability.

[0011] Patent Document 2 discloses a polyamide resin composition obtained by mixing airbag residue powder into a polyamide resin, and states that mechanical properties can be maintained.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: International Publication No. 2012 / 035673

[0015] Patent Document 2: International Publication No. 2012 / 025465 Summary of the Invention

[0016] Problems to be solved by the invention

[0017] However, Patent Document 1 does not describe the silicone resin falling off from the injection-molded article or the silicone resin adhering to the surface of the injection mold, and these problems still exist.

[0018] Furthermore, Patent Document 2 does not describe the silicone resin falling off from the injection-molded article or the silicone resin adhering to the surface of the injection mold, and these problems still exist.

[0019] Therefore, in view of these problems in the prior art, the present invention aims to provide a polyamide resin composition and a molded article obtained by molding the resin composition. Even when the polyamide resin composition is a polyamide resin molded article containing other resin components, especially a polyamide resin molded article having a layer of other resin components formed on the surface, the polyamide resin composition contains a silicone resin as an impurity, and the silicone resin can be suppressed from falling off from the molded article formed by injection molding the composition and from adhering to the mold surface during molding, and the molded article also has excellent mechanical properties.

[0020] Another object of the present invention is to provide a method for producing the above-mentioned polyamide resin composition suitable for material recycling, and a method for producing a molded article obtained by molding the polyamide resin composition obtained by the production method.

[0021] Means of solving the problem

[0022] In order to solve the above-mentioned problems, the present invention has the following configuration.

[0023] (1) A polyamide resin composition comprising 0.01 to 12 parts by weight of a silicone resin (B) and 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, per 100 parts by weight of a polyamide resin (A).

[0024] (2) The polyamide resin composition according to (1), further comprising 0.01 to 5 parts by weight of an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia.

[0025] (3) The polyamide resin composition according to (1), further comprising 0.01 to 5 parts by weight of an acid anhydride (E).

[0026] (4) A molded article obtained by molding the polyamide resin composition according to any one of (1) to (3).

[0027] (5) A method for producing a polyamide resin composition, characterized in that, when producing the polyamide resin composition described in (1), the silicone resin layer is separated from a polyamide resin composite having a silicone resin layer formed on the surface of a polyamide resin molded body in such a manner that 0.01 to 12 parts by weight of the silicone resin layer remain relative to 100 parts by weight of the polyamide resin, the polyamide resin composite after the silicone resin layer is separated is temporarily made into pellets or fragments of a composition (AB), or the polyamide resin composite after the silicone resin layer is separated is retained in its original form, and 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group and an acid anhydride group is melt-kneaded into the pellets or fragments, or into the original form of the polyamide resin composite.

[0028] (6) A method for producing a polyamide resin composition, characterized in that, when producing the polyamide resin composition described in (2), the silicone resin layer is separated from a polyamide resin composite having a silicone resin layer formed on the surface of a polyamide resin molded body so that 0.01 to 12 parts by weight of the silicone resin layer remain relative to 100 parts by weight of the polyamide resin, the polyamide resin composite after the silicone resin layer is separated is temporarily made into pellets or fragments of a composition (AB), or the polyamide resin composite after the silicone resin layer is separated is retained in its original form, and 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group and an acid anhydride group and 0.01 to 5 parts by weight of an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia are melt-kneaded into the pellets or fragments or into the original form of the polyamide resin composite.

[0029] (7) A method for producing a polyamide resin composition, characterized in that, when producing the polyamide resin composition described in (3), the silicone resin layer is separated from a polyamide resin composite having a silicone resin layer formed on the surface of a polyamide resin molded body in such a manner that 0.01 to 12 parts by weight of the silicone resin layer remain relative to 100 parts by weight of the polyamide resin, the polyamide resin composite after the silicone resin layer is separated is temporarily made into pellets or fragments of a composition (AB), or the polyamide resin composite after the silicone resin layer is separated is retained in its original form, and 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group and an acid anhydride group, and 0.01 to 5 parts by weight of an acid anhydride (E) are melt-kneaded into the pellets or fragments, or into the original form of the polyamide resin composite.

[0030] (8) A method for producing a molded article, comprising producing a polyamide resin composition by the production method according to any one of (5) to (7), and molding the polyamide resin composition.

[0031] Effects of the Invention

[0032] According to the present invention, a polyamide resin composition can be provided that, even when the polyamide resin composition contains an organosilicon resin as an impurity, can suppress the loss of the organosilicon resin from a molded article obtained by injection molding the polyamide resin composition and the adhesion of the organosilicon resin to the mold surface during molding, and the molded article also has excellent mechanical properties. Therefore, a polyamide resin composition suitable for material recycling, a method for producing the same, and a molded article using the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of the ball-plate test apparatus used for evaluating the polyamide resin composition of the present invention. DETAILED DESCRIPTION

[0034] Hereinafter, the present invention will be described in detail with reference to the embodiments.

[0035] The polyamide resin composition of the present invention comprises a polyamide resin (A), a silicone resin (B), and a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group.

[0036] The polyamide resin (A) constituting the polyamide resin composition of the present invention is a polyamide obtained by polycondensation of a lactam having a three-membered ring or more, a polymerizable ω-amino acid, or a dibasic acid with a diamine. Specifically, polymers of ε-caprolactam, aminocaproic acid, enantholactam, 7-aminoheptanoic acid, 11-aminoundecanoic acid, 9-aminononanoic acid, α-pyrrolidone, α-piperidone, etc., tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, nonamethylenediamine, undecamethylenediamine, dodecamethylenediamine, m-xylylenediamine, p-xylylenediamine, 2-methylpentamethylenediamine, 2,2,4- / 2,4,4-trimethylhexamethylenediamine, 5-methylnonanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, etc. can be mentioned. Polymers obtained by polycondensing alicyclic or aromatic diamines such as cyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminopropyl)piperazine, and aminoethylpiperazine with alicyclic or aromatic dicarboxylic acids such as adipic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodium sulfoisophthalate, 2,6-naphthalenedicarboxylic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, and cyclohexanedicarboxylic acid, or copolymers thereof. These polyamide resins may be polyamide resins whose terminals are capped with carboxylic acids or amines for molecular weight adjustment.

[0037] Specifically, polyamide 4, polyamide 6, polyamide 7, polyamide 8, polyamide 11, polyamide 12, polyamide 46, polyamide 56, polyamide 66, polyamide 69, polyamide 410, polyamide 510, polyamide 610, polyamide 611, polyamide 612, polyamide 66 / 6T copolymer, polyamide 6 / 66 copolymer, polyamide 6 / 12 copolymer, polyamide 6 / 6T copolymer, polyamide 6T / 6I copolymer, polyamide MXD6, etc. can be mentioned. Mixtures of multiple polyamide resins are also possible. Among them, polyamide 6, polyamide 66, and mixtures thereof are preferred from the perspective of versatility in various applications during recycling, and polyamide 66 is particularly preferred.

[0038] Examples of the silicone resin (B) constituting the polyamide resin composition of the present invention include silicone oils or silicone rubbers having an average composition formula R 1 m SiO (4-m) / 2 In the above composition formula, m represents a number from 1.98 to 2.02, R 1represents an alkenyl group and an organic group other than an alkenyl group. The silicone resin preferably has two or more groups selected from alkenyl groups and organic groups other than an alkenyl group per molecule.

[0039] When the silicone resin (B) is an organopolysiloxane having an average of two or more groups selected from alkenyl groups and organic groups other than alkenyl groups per molecule, it has the advantages of excellent compatibility and adhesion with the polyamide resin in addition to the mechanical properties and heat resistance of the organopolysiloxane itself.

[0040] Examples of such alkenyl groups include vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl. Among these, vinyl groups are preferred from the perspective of the vulcanization characteristics and heat resistance of the organopolysiloxane. The vinyl content is typically approximately 0.03 to 0.3 mol% per 100 mol% of the organopolysiloxane.

[0041] An organic group other than an alkenyl group is bonded to a silicon atom. Examples of such organic groups include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl; aryl groups such as phenyl, tolyl, and xylyl; and halogenated alkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. Methyl and phenyl groups are preferred because they offer excellent balance of organosiloxane properties and low-temperature resistance.

[0042] An organic group other than the alkenyl group described above may be bonded to the organopolysiloxane as the silicone resin (B) within a range not impairing the effects of the present invention.

[0043] Examples of the molecular structure of the organopolysiloxane include a linear structure, a partially branched linear structure, a branched chain structure, and a network structure.

[0044] Examples of such organopolysiloxanes include dimethylpolysiloxanes terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymers terminated with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylvinylsiloxane copolymers terminated with trimethylsiloxy groups at both ends of the molecular chain, dimethylpolysiloxane-methylvinylsiloxane-phenylmethylpolysiloxane copolymers, organopolysiloxanes in which a part or all of the methyl groups of these organopolysiloxanes are substituted with alkyl groups such as ethyl and propyl groups; aryl groups such as phenyl and tolyl groups; or haloalkyl groups such as 3,3,3-trifluoropropyl groups, organopolysiloxanes in which a part or all of the vinyl groups of these organopolysiloxanes are substituted with alkenyl groups such as allyl and propenyl groups, and mixtures of two or more of these organopolysiloxanes.

[0045] From the perspective of suppressing the silicone resin from falling out of the injection-molded article obtained in the present invention and suppressing the silicone resin from adhering to the mold surface, the degree of polymerization of the organopolysiloxane is preferably 2 or more, more preferably 3-300, and even more preferably 5-200.

[0046] In the polyamide resin composition of the present invention, the amount of the silicone resin (B) is 0.01 to 12 parts by weight relative to 100 parts by weight of the polyamide resin. If the amount of the silicone resin (B) is less than 0.01 parts by weight, even without the method of the present invention, the silicone resin will not fall off from the injection molded article and the amount of silicone resin attached to the mold surface will be small. In addition, if the amount of the silicone resin (B) exceeds 12 parts by weight, the silicone resin will not fall off from the injection molded article obtained by the present invention and the amount of silicone resin attached to the mold surface will increase, and the mechanical properties will also decrease, which is not preferred. The amount of the silicone resin (B) is preferably 0.01 to 10.5 parts by weight, and more preferably 0.01 to 5 parts by weight.

[0047] The silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group and an anhydride group, which constitutes the polyamide resin composition of the present invention, is an organosilane compound such as an alkoxysilane having at least one functional group selected from an isocyanate group, an epoxy group and an anhydride group. When the specific silane coupling agent (C) is used, the isocyanate group, epoxy group and anhydride group as the functional groups of the silane coupling agent (C) are chemically bonded to the terminal amino group and the terminal carboxyl group of the polyamide resin (A). The silane portion of the silane coupling agent (C) has a structure similar to that of the silicone resin (B) and thus interacts with each other. Therefore, the silicone resin (B) is fixed on the polyamide resin (A), which can inhibit the silicone resin from falling off from the injection molded product and the adhesion of the silicone resin to the mold surface during molding, and the mechanical properties of the molded product are also improved. Among them, the silane coupling agent having an isocyanate group has a high reactivity with the terminal amino group and the terminal carboxyl group of the polyamide resin (A), and is therefore particularly preferred.

[0048] Two or more silane coupling agents (C) having at least one functional group selected from the group consisting of an isocyanate group, an epoxy group, and an acid anhydride group may be used simultaneously.

[0049] In the polyamide resin composition of the present invention, the amount of the silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group is 0.01 to 5 parts by weight relative to 100 parts by weight of the polyamide resin. When the amount of the silane coupling agent (C) is less than 0.01 parts by weight, the silicone resin from the molded article obtained by injection molding the polyamide resin composition of the present invention and the amount of silicone resin attached to the mold surface during molding increase, which is not preferred. In addition, when the amount of the silane coupling agent (C) exceeds 5 parts by weight, the polyamide resin composition becomes significantly thickened, gelling occurs, and the polyamide resin composition cannot be collected (especially cannot be collected in the form of material recycling), or the mechanical properties of the molded article are reduced, which is not preferred. The amount of the silane coupling agent (C) is preferably 0.02 to 4 parts by weight, and more preferably 0.05 to 3.5 parts by weight.

[0050] The polyamide resin composition of the present invention preferably further contains 0.01 to 5 parts by weight of an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia, within a range that does not impair its properties. It is speculated that the ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia has high compatibility with the polyamide resin (A) and is finely dispersed to a certain extent in the polyamide resin (A). As a result, it reacts with the polyamide resin (A) to increase the number of terminal carboxyl groups, thereby increasing the amount of chemical bonding with the silane coupling agent (C), further suppressing the loss of the silicone resin from the injection molded article and the amount of silicone resin adhering to the mold surface. From the perspective of balancing the suppression of the loss of the silicone resin from the injection molded article, the adhesion of the silicone resin to the mold surface, and the mechanical properties of the molded article, the amount of ammonium salt (D) is more preferably 0.05 to 4 parts by weight.

[0051] Ammonium salts of dicarboxylic acids having 5 or less carbon atoms are also presumably highly compatible with the polyamide resin (A) and are therefore dispersed in the polyamide resin (A). However, ammonium salts of dicarboxylic acids having 5 or less carbon atoms have low molecular weights and are decomposed during the production of the polyamide composition. Therefore, ammonium salts of dicarboxylic acids having 6 to 12 carbon atoms are preferably used.

[0052] Specific examples of the ammonium salt (D) include diammonium adipate, diammonium pimelate, diammonium suberate, diammonium azelate, diammonium sebacate, ammonium dodecane dioate, and ammonium benzoate. If necessary, two or more of these may be used simultaneously. Among these, diammonium adipate and diammonium sebacate are preferred from the perspectives of preventing the silicone resin from falling off the injection-molded article and adhering to the mold surface, as well as mechanical properties, raw material availability, and cost.

[0053] The polyamide resin composition of the present invention preferably further contains 0.01 to 5 parts by weight of an acid anhydride (E), within a range that does not impair its properties. The acid anhydride (E) reacts with the polyamide resin (A) to increase the number of terminal carboxyl groups, thereby increasing the amount of chemical bonding with the silane coupling agent (C), further suppressing the release of the silicone resin from injection-molded articles and the amount of silicone resin adhering to the mold surface. To balance the suppression of silicone resin release from injection-molded articles, the adhesion of the silicone resin to the mold surface, and the mechanical properties of the molded article, the amount of acid anhydride (E) is more preferably 0.05 to 4 parts by weight.

[0054] Specific examples of the acid anhydride (E) include benzoic anhydride, isobutyric anhydride, itaconic anhydride, octanoic anhydride, glutaric anhydride, succinic anhydride, acetic anhydride, dimethylmaleic anhydride, capric anhydride, trimellitic anhydride, 1,8-naphthalene dicarboxylic anhydride, phthalic anhydride, maleic anhydride and derivatives thereof. Among them, succinic anhydride is preferably used.

[0055] The polyamide resin composition of the present invention may contain other components in addition to the polyamide resin (A), the silicone resin (B), the silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, the ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia, and the acid anhydride (E) within a range that does not impair its properties.

[0056] For example, as other components, a thermoplastic resin other than the polyamide resin (A) component may be contained. Examples of the thermoplastic resin include polyamide resins other than the polyamide resin (A), polyester resins, polyphenylene sulfide resins, polyphenylene ether resins, polycarbonate resins, polylactic acid resins, polyacetal resins, polysulfone resins, tetrafluoroethylene resins, polyetherimide resins, polyamideimide resins, polyimide resins, polyethersulfone resins, polyetherketone resins, polysulfideetherketone resins, polyetheretherketone resins, polyethylene resins, polyolefin resins such as polypropylene resins, polystyrene resins, styrene resins such as ABS resins, polyalkylene oxide resins, polybutadiene, polyisoprene, random copolymers and block copolymers of styrene / butadiene, hydrogenated products of such block copolymers, acrylonitrile / butadiene copolymers, butadiene / isoprene The present invention also includes diene rubbers such as ethylene copolymers, random copolymers and block copolymers of ethylene / propylene, random copolymers and block copolymers of ethylene / butene, copolymers of ethylene / α-olefins, ethylene / unsaturated carboxylic acid ester copolymers such as ethylene / acrylate and ethylene / methacrylate, acrylate / butadiene copolymers such as butyl acrylate / butadiene copolymers, copolymers of ethylene and fatty acid vinyl esters such as ethylene / vinyl acetate copolymers, ethylene / propylene / ethylidene norbornene copolymers, ethylene / propylene / non-conjugated diene terpolymers such as ethylene / propylene / hexadiene copolymers, butene / isoprene copolymers, chlorinated polyethylene, polyamide elastomers, polyester elastomers, thermoplastic elastomers such as ionomers of carboxylic acid metal salts, and the like.

[0057] When the above-mentioned thermoplastic resin is used, the content thereof is not particularly limited, but is preferably 0.1 parts by weight or more and less than 10 parts by weight relative to 100 parts by weight of the polyamide resin (A).

[0058] In addition, an inorganic filler may be contained as another component. The inorganic filler may be in a fibrous or non-fibrous form.

[0059] As inorganic filling material, for example, can enumerate, glass filler, carbon fiber, potassium titanate whisker, zinc oxide whisker, aluminum borate whisker, aluminum oxide fiber, silicon carbide fiber, ceramic fiber, asbestos fiber, gypsum fiber, metal fiber such as fibrous inorganic filling material, wollastonite, zeolite, sericite, kaolin, mica, clay, pyrophyllite, bentonite, asbestos, talc, metal silicates such as aluminum silicate, aluminum oxide, silicon oxide, magnesium oxide, zirconium oxide, titanium oxide, iron oxide such as carbonate, calcium carbonate, magnesium carbonate, dolomite such as carbonate, calcium sulfate, metal sulfate such as barium sulfate, magnesium hydroxide, calcium hydroxide, aluminum hydroxide such as metal hydroxide, glass beads, ceramic beads, boron nitride and silicon carbide and other non-fibrous inorganic filling materials, they can be hollow.Also these inorganic filling materials can be used in combination of two or more. Furthermore, these fibrous and / or non-fibrous inorganic fillers may be pretreated with a coupling agent such as an isocyanate compound, an organosilane compound, an organotitanate compound, an organoborane compound, or an epoxy compound. The coupling agent used in this pretreatment improves the adhesion of the inorganic filler to the polyamide resin (A), and this function is fundamentally different from the silane coupling agent (C) in the present invention, which is intended to fix the silicone resin (B) to the polyamide resin (A).

[0060] There is no particular limitation on the glass filler, and known glass fillers can be used. Glass fibers are available in the form of chopped strands, roving strands, milled fibers, etc. cut into a specified length. Generally, glass fibers with an average fiber diameter of 5 to 15 μm are preferably used. When chopped strands are used, there is no particular limitation on the fiber length, and it is preferred to use a glass filler with a strand length of about 3 mm that has good extrusion and mixing operability. When roving strands are used, compounding can be performed by directly feeding the roving strands into an extruder using a known technique. Two or more of these glass fillers can be used in combination.

[0061] There is no particular limitation on the carbon fiber, and various well-known carbon fibers can be used, such as carbon fibers made from polyacrylonitrile (PAN), pitch, rayon, lignin, hydrocarbon gas, etc., graphite fibers, and fibers coated with metals. Among them, PAN-based carbon fibers that can improve mechanical properties can be preferably used. Carbon fibers usually have shapes such as chopped strands, roving strands, and milled fibers cut into a specified length, and have a diameter of 15 μm or less, preferably 5 to 10 μm. When using chopped strands, there is no particular limitation on the fiber length, and it is preferred to use chopped strands of a strand length that has good extrusion and mixing operability. When using roving strands, composites can be made by a known technique of directly feeding the roving strands into an extruder. Chopped strands are preferably used in the present invention, and from the aspects of manufacturing cost and stability in the production process, the number of filaments of the carbon fiber strands as the chopped carbon fiber precursor is preferably 1,000 to 150,000.

[0062] When the inorganic filler is used, the content thereof is not limited, but is preferably 1 part by weight or more and less than 200 parts by weight relative to 100 parts by weight of the polyamide resin (A).

[0063] Furthermore, as other components, one or more common additives such as ultraviolet absorbers, antioxidants, heat stabilizers, anti-discoloration agents, weathering agents, release agents, lubricants, antistatic agents, and colorants including dyes / pigments may be added within a range that does not impair the purpose of the present invention.

[0064] Examples of such additives include ultraviolet absorbers such as benzotriazoles, phenols, and phosphorus-based agents; antioxidants such as copper, hindered phenols, phosphorus, and sulfur-based agents; heat stabilizers; organic nucleating agents such as metal salts of aromatic carboxylic acids, sorbitol derivatives, organic phosphates, and aromatic amide compounds; weathering agents such as resorcinols, salicylates, benzotriazoles, benzophenones, and hindered amines; metal stearates such as calcium stearate and sodium stearate; metal behenates such as sodium behenate; mold release agents such as alcohols, amides, bisamides, ethylene bisstearamide, and higher fatty acid esters; lubricants such as octyl parahydroxybenzoate and waxes; alkyl sulfate-type anions; quaternary ammonium salt-type cations; nonionic antistatic agents such as polyoxyethylene sorbitan monostearate; and betaine-based amphoteric antistatic agents. Among them, sodium stearate or sodium behenate is preferably used from the viewpoint of suppressing the silicone resin from falling off from the injection molded article, preventing the silicone resin from adhering to the mold surface, and balancing the mechanical properties of the molded article.

[0065] The content thereof is not particularly limited, but is preferably 0.01 parts by weight or more and less than 5 parts by weight relative to 100 parts by weight of the polyamide resin (A).

[0066] In evaluating the polyamide resin composition of the present invention, the method for evaluating the amount of silicone resin removed from an injection-molded article is as follows. Polyamide resin composition pellets are injection-molded to form square test pieces with a thickness of 3 mm, a length of 100 mm, and a width of 100 mm. The resulting test pieces are subjected to a ball-and-plate friction / wear test. Figure 1The schematic diagram of the structure of the ball-plate test device used in the evaluation is shown in the figure. First, prepare a ball (φ6mm) 1 made of polyurethane and fix the ball 1 on the bracket 2. Then, make the ball 1 fixed on the bracket 2 contact the upper surface of the test piece 3. While applying a load of 500gf from the ball 1 to the test piece 3, the test piece is reciprocated at a sliding speed of 5m / min, a reciprocating distance of 160mm, and a reciprocating number of 100 times under the conditions of room temperature and atmospheric pressure, and the amount of silicone shedding is visually evaluated. When almost no silicone shedding occurs, it is determined to be very excellent (◎), when a small amount of shedding occurs, it is determined to be excellent (○), when a moderate amount of shedding occurs, it is determined to be slightly better (△), and when a large amount of shedding occurs, it is determined to be poor (×).

[0067] In the evaluation of the polyamide resin composition of the present invention, the method for evaluating the adhesion of the silicone resin to the mold surface during molding is as follows. Using pellets of the polyamide resin composition, ISO Type-A test pieces were continuously injection-molded 100 times, and the adhesion of the powdered silicone to the mold after injection molding was visually confirmed. A score of very good (◎) was given when there was almost no adhesion, excellent (○) when there was a slight amount of adhesion, slightly good (△) when there was a moderate amount of adhesion, and poor (×) when there was a large amount of adhesion.

[0068] Next, the method for producing the polyamide resin composition of the present invention will be described below.

[0069] The method for producing a polyamide resin composition of the present invention uses a polyamide resin composite having a silicone resin layer formed on at least a portion of the surface of a polyamide resin molded body.

[0070] Specifically, the method for producing a polyamide resin composition of the present invention is as follows: 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, and optionally 0.01 to 5 parts by weight of an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia, and 0.01 to 5 parts by weight of an acid anhydride (E) are melt-kneaded into a composition (AB) obtained by separating a silicone resin layer from the above-mentioned polyamide resin composite so that 0.01 to 12 parts by weight remain relative to 100 parts by weight of the polyamide resin.

[0071] More specifically, the method comprises separating the silicone resin layer from the polyamide resin composite so that 0.01 to 12 parts by weight of the silicone resin layer remains relative to 100 parts by weight of the polyamide resin; temporarily converting the polyamide resin composite from which the silicone resin layer has been separated into pellets or chips of the composition (AB); or, if the polyamide resin composite is originally small in size and can be directly inserted into a melt-kneading apparatus, retaining the polyamide resin composite from which the silicone resin layer has been separated; and melt-kneading 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, and optionally melt-kneading 0.01 to 5 parts by weight of an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia, and 0.01 to 5 parts by weight of an acid anhydride (E).

[0072] By producing the polyamide resin composition of the present invention in this manner, even if the polyamide resin is contained as an impurity, it is possible to obtain a polyamide resin composition in which the silicone resin is suppressed from falling off from an injection-molded article and adhesion of the silicone resin to the mold surface during molding is suppressed, and the molded article also has excellent mechanical properties. Furthermore, a polyamide resin composition that can be stably recycled as a material can be obtained.

[0073] Specific methods for separating the silicone resin layer from the polyamide resin composite are not particularly limited, and the following methods may be mentioned. Specifically, methods include immersing the polyamide resin composite having the silicone resin layer formed on the surface of the polyamide resin molded body in an alkaline solution and, if necessary, heating the polyamide resin layer to swell and separate it; methods for pulverizing the polyamide resin composite and then extracting only the polyamide resin by utilizing density differences; and methods for removing the silicone resin from the polyamide resin composite using a solution capable of dissolving the silicone resin. Furthermore, the use of an agent other than the alkaline solution can further enhance the separation of the silicone resin layer.

[0074] Even if the silicone resin layer is not separated from the polyamide resin composite, the step of separating the silicone resin layer from the polyamide resin composite is not necessarily required as long as the silicone resin (B) accounts for 0.01 to 12 parts by weight relative to 100 parts by weight of the polyamide resin (A).

[0075] For the molded products of said polyamide resin composition in the present invention, as long as polyamide resin composition is melted, the molded products that are obtained are just not particularly limited.As the form of molded products, various molded products such as film, sheet, fiber, fabric, braid, nonwoven, bottle, container can be enumerated.In addition, for the forming method of polyamide resin composition, as the forming method of film, sheet, bottle or container etc., extrusion molding, injection molding, calendering molding, calendering molding (Calender molding), blow molding, blowing molding etc. can be enumerated, as the forming method of fiber, fabric, braid or nonwoven etc., forming methods such as melt spinning, woven, water jet braiding, air jet braiding, single tricot warp knitting, single bar warp knitting, single bar warp knitting, warp knitting such as satin braiding, flat braiding, rib braiding, pearl braiding, chemical bonding, thermal bonding, acupuncture, spunlace, spunbonding can be enumerated.

[0076] As described above, the polyamide resin composite used in the present invention comprises a silicone resin layer formed on the surface of a polyamide resin molded article. Examples of methods for forming the silicone resin layer include coating methods (such as doctor blade coating, kiss coating, reverse coating, teasing coating, slot die coating, and lip coating), dipping methods, printing methods (such as screen, roller, rotary, and gravure), transfer methods, lamination methods, and spraying methods such as spraying. Typical methods include coating of a polymer solution or polymer melt and lamination of polymer sheets.

[0077] When the polyamide resin composite used in the present invention is processed in the form of fibers, fabrics, braids, non-woven fabrics, etc., the silicone resin in the silicone resin layer formed on the surface of the polyamide resin molded body may penetrate into the spaces between the fibers of the fibers, fabrics, braids, or non-woven fabrics. Therefore, when the silicone resin layer is separated from the polyamide resin composite, the silicone resin may sometimes penetrate into the spaces between the fibers and remain. Even in this case, by obtaining a polyamide resin composition in which the amount of the silicone resin (B) and the silane coupling agent (C) having at least one functional group selected from isocyanate groups, epoxy groups, and acid anhydride groups is within the range specified in the present invention, it is possible to suppress the silicone resin from falling off the molded product after injection molding and the silicone resin from adhering to the mold surface during molding. In addition, the molded product also has excellent mechanical properties, and a polyamide resin composition suitable for recycling (particularly material recycling) can be obtained.

[0078] In the present invention, the amount of silicone resin remaining in the polyamide resin composite is determined, for example, as follows. A fluorescent X-ray analyzer (System 3370E, manufactured by Rigaku Electric Co., Ltd.) is used to quantitatively analyze the silicone atoms in a test piece obtained by injection molding. Measurements are performed using an Rh-Kα X-ray source at an output of 50 kV and 50 mA. The ratio of silicone atoms to the silicone resin is calculated as X%. The amount of silicone resin per 100 parts by weight of the polyamide resin is calculated from the amount of silicone determined by analysis.

[0079] When the polyamide resin molded article used in the present invention is in the form of a fabric such as a fiber, woven fabric, knitted fabric, or non-woven fabric as described above, specific examples of the polyamide resin composite include clothing articles such as rain gear, winter clothing, ski wear, jackets, swimwear, and uniforms. Furthermore, industrial articles include air bags, curtains, carpets, fishing nets, and ship slings.

[0080] When the shape of the polyamide resin molded body used in the present invention is other than cloth, specific examples of the polyamide resin composite having a silicone resin layer formed on the surface of such a polyamide resin molded body include extruded products such as wires and cables, pipes, and hoses, and injection molded products used in electrical and electronic components such as sensors and connectors.

[0081] As a method for melt-kneading a composition (AB) obtained by separating the silicone resin layer from the polyamide resin composite, a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, and optionally an ammonium salt (D) formed from a dicarboxylic acid having 6 to 12 carbon atoms and ammonia, and 0.01 to 5 parts by weight of an acid anhydride (E), melt-kneading using an extruder is preferred from the perspectives of productivity and kneading properties. Here, the composition (AB) obtained by separating the silicone resin layer from the polyamide resin composite may be pelletized by passing it through a single-screw extruder, and then the silane coupling agent (C) may be added and melt-kneaded using an extruder. Alternatively, the composition (AB) may be melt-kneaded directly with the silane coupling agent (C) in the extruder in its separated form. Alternatively, the composition (AB) may be passed through an extruder, and the silane coupling agent (C) may be added in the latter half of the extruder and melt-kneaded. As the extruder used in melt kneading, a twin-screw extruder is preferred. For example, a method in which the components are pre-mixed and supplied to a twin-screw extruder with a barrel temperature set at 230°C to 300°C for melt kneading can be cited. As the screw structure, it is preferred to have 1 to 5 kneading zones. When the ratio (%) of the total length of the above-mentioned kneading zones to the total length of the screw is specified as (total length of the kneading zones) ÷ (total length of the screw) × 100, it is preferably 5 to 40%. It is also preferred to use a method in which the generated gas is removed by exposing the extruder to a vacuum state midway. The resin composition extruded after melt kneading is usually drawn into a strand shape and processed into pellets by a pelletizer.

[0082] The polyamide resin composition of the present invention can be molded by any method. Examples of molding methods include injection molding, extrusion molding, hollow molding, calendaring molding, compression molding, vacuum molding, foam molding, blow molding, and rotational molding. Examples of molded shapes include box-like, plate-like, fibrous, concave-convex, strand-like, film-like, sheet-like, tubular, hollow, box-like, and claw-like shapes.

[0083] The resulting molded products can be used in various applications such as automotive parts, vehicle-related parts, building material-related parts, general / industrial machinery parts, electrical and electronic parts, sporting goods, daily necessities, home / office supplies, and furniture parts.

[0084] Example

[0085] The present invention will be described in more detail below with reference to Examples. The present invention is not limited thereto. The evaluation methods for various properties in the Examples and Comparative Examples are shown below.

[0086] (1) Amount of silicone resin remaining in polyamide resin compositions (AB-1) to (AB-7) after separation of silicone resin from polyamide resin composite

[0087] Using an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd., the polyamide resin compositions (AB-1) to (AB-7) described later were injection molded under the conditions of a barrel temperature of 280°C and a mold surface temperature of 80°C to produce test pieces of ISO Type-A standard. For the obtained test pieces, a fluorescent X-ray analyzer (manufactured by Rigaku Electric Co., Ltd., "System 3370E") was used to perform quantitative analysis of silicone atoms. It should be noted that the measurement was performed under the conditions that the X-ray source was Rh-Kα rays, the output power was 50 kV, and 50 mA. Here, the proportion of silicone atoms in the silicone resin is considered to be 37%, and the amount of silicone resin relative to 100 parts by weight of the polyamide resin is calculated from the amount of silicone obtained by analysis.

[0088] (2) Tensile strength and elongation at break

[0089] The pellets obtained in the Examples and Comparative Examples were injection molded using a NEX1000 injection molding machine manufactured by Nissei Plastic Industry Co., Ltd. at a cylinder temperature of 280°C and a mold surface temperature of 80°C to produce ISO Type-A test specimens. The tensile strength and tensile elongation at break were measured using the resulting test specimens according to ISO 527-1 and 527-2.

[0090] (3) Evaluation of the amount of silicone resin falling off from injection molded products

[0091] The pellets obtained in each example and comparative example were injection molded using an injection molding machine NEX1000 manufactured by Nissei Plastic Industry Co., Ltd. at a barrel temperature of 280°C and a mold surface temperature of 80°C to produce square test pieces with a thickness of 3 mm, a length of 100 mm, and a width of 100 mm. The plate-ball friction / wear test described above was performed on each of the test pieces. Figure 1 In the ball-plate test apparatus for evaluation, a schematic structure of which is shown in the figure, a polyurethane ball (φ6mm) 1 is first prepared and the ball 1 is fixed to a bracket 2. Next, the ball 1 fixed to the bracket 2 is brought into contact with the upper surface of the test piece 3. A load of 500gf is applied from one side of the ball to one side of the test piece, and under the conditions of room temperature and atmospheric pressure, the sliding speed of the test piece is set to 5m / min, the reciprocating distance per time is 160mm, and the number of reciprocations is 100 times, and the amount of silicone shedding is visually evaluated. When almost no silicone shedding occurs, it is considered very excellent (◎), when a small amount of shedding occurs, it is considered excellent (○), when a moderate amount of shedding occurs, it is considered slightly better (△), and when a large amount of shedding occurs, it is considered poor (×).

[0092] (4) Evaluation of silicone resin adhesion to mold surface

[0093] After injection molding in (2) above, adhesion of the powdered silicone to the mold was visually inspected for 100 consecutive injections. A case where almost no adhesion occurred was rated as very good (◎), a case where a small amount of adhesion occurred was rated as excellent (○), a case where a moderate amount of adhesion occurred was rated as slightly good (△), and a case where a large amount of adhesion occurred was rated as poor (×).

[0094] In addition, each raw material of the resin composition used in Examples and Comparative Examples is as follows.

[0095] (S-1) Polyamide resin composite containing polyamide 66 base cloth

[0096] Polyamide 66 base fabric (plain weave, relative viscosity: 3.1, single yarn denier: 6 denier, total denier: 420 denier, warp density: 45 strands / inch, weft density: 45 strands / inch, unit area weight: 300 g / m 2 A polyamide resin molded article (100 parts by weight, 0.35 mm thick) was prepared. A silicone resin composition containing 10 parts by weight of a crosslinking agent (Shin-Etsu Chemical Co., Ltd., trade name "CX-32-1124") (a copolymer of dimethylpolysiloxane, methylvinylpolysiloxane, and phenylmethylpolysiloxane) was applied to one side of the polyamide resin molded article using a knife coating method. The article was dried at 120°C for 1 minute. The article was then cooled at 185°C for 2 minutes to form a silicone resin layer on the surface of the polyamide resin molded article, producing a polyamide resin composite (S-1). The surface of the polyamide 66 base fabric on which the silicone resin layer was formed in this polyamide resin composite (S-1) had a warp density and a weft density of 46 threads / inch, and the silicone resin layer was applied in an amount of 18 parts by weight per 100 parts by weight of the polyamide 66 resin. Furthermore, the polyamide resin composite can be sewn to produce an airbag for automobiles.

[0097] (S-2) Automobile airbags

[0098] Automobile airbag comprising a polyamide 66 fabric having a silicone resin layer composed of a methyl vinyl silicone resin formed on the fabric surface (amount of silicone resin layer: 13 parts by weight per 100 parts by weight of the fabric)

[0099] (S-3) Polyamide resin composite containing polyamide 66 base cloth

[0100] Polyamide 66 base fabric (plain weave, relative viscosity: 3.1, single yarn denier: 6 denier, total denier: 420 denier, warp density: 45 strands / inch, weft density: 45 strands / inch, unit area weight: 300 g / m 2A polyamide resin molded article (with a thickness of 0.35 mm) was prepared. Using a knife coating method, a silicone resin composition containing 10 parts by weight of a crosslinking agent (Shin-Etsu Chemical Co., Ltd., trade name "CX-32-1124") (a copolymer of dimethylpolysiloxane, methylvinylpolysiloxane, and phenylmethylpolysiloxane) was applied to one side of the polyamide resin molded article. The article was dried at 120°C for 1 minute. The article was then cooled at 185°C for 2 minutes to form a silicone resin layer on the surface of the polyamide resin molded article, producing a polyamide resin composite (S-3). The polyamide 66 base fabric on which the silicone resin layer was formed in this polyamide resin composite (S-3) had a warp density and a weft density of 46 threads / inch, and the silicone resin layer was applied in an amount of 7.0 parts by weight per 100 parts by weight of the polyamide 66 resin. Furthermore, the polyamide resin composite can be sewn to produce an airbag for automobiles.

[0101] (A-1) Polyamide 66 resin having a viscosity of 135 ml / g as measured in accordance with JIS K 6933 (2013)

[0102] (C-1) Isocyanate group-containing silane coupling agent "KBE-9007N" (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0103] (C-2) Epoxy-containing silane coupling agent "KBM-303" (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0104] (C-3) Acid anhydride group-containing silane coupling agent "X-12-967C" (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0105] (D-1) Diammonium adipate (manufactured by Toyama Pharmaceutical Industry Co., Ltd.)

[0106] (E-1) Succinic anhydride "Rikasit SA-25" (manufactured by Shinnippon Rika Co., Ltd.)

[0107] (F-1) Glass fiber "T-253" (manufactured by Nippon Electric Glass Co., Ltd.)

[0108] (G-1) Amino-containing silane coupling agent "KBM-903" (manufactured by Shin-Etsu Chemical Co., Ltd.)

[0109] (H-1) Sodium behenate "NS-7" (manufactured by Nitto Kasei Kogyo Co., Ltd.)

[0110] (I-1) Sodium stearate "NA-ST" (manufactured by Nitto Kasei Kogyo Co., Ltd.)

[0111] (Polyamide resin composition after separation of silicone resin from polyamide resin composite: AB-1)

[0112] The polyamide resin composite (S-1) was cut into 300 x 300 mm squares. A 15% sodium hydroxide aqueous solution was prepared by adding 750 g of sodium hydroxide, 100 g of ethylenediamine, and 4150 ml of water to an 8 L glass container. The slices were immersed in this aqueous solution, maintained at 60°C, and heated for 2 hours. This treatment is designated as treatment (X).

[0113] The silicone resin layer was separated from the polyamide resin composite (S-1) by the above treatment (X), yielding a treated sheet (i.e., a polyamide resin molded article in which the silicone resin layer was separated from the polyamide resin composite and the silicone resin remained on the surface). This sheet was chopped into 10×10 mm pieces and pelletized using a 70 mmφ single-screw extruder at a barrel temperature of 280°C and a discharge rate of 200 kg / hr. The resulting pellets were vacuum-dried at 80°C for at least 12 hours to yield pellets of a polyamide resin composition (AB-1). The residual silicone resin content of the polyamide resin composition (AB-1) was 1.5 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0114] (Polyamide resin composition after separation of silicone resin from polyamide resin composite: AB-2)

[0115] The same treatment as in (AB-1) was performed except that the heating time was set to 1 hour to obtain pellets of a polyamide resin composition (AB-2). The residual amount of silicone resin in the polyamide resin composition (AB-2) was 3.0 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0116] (Polyamide resin composition after separation of silicone resin from polyamide resin composite: AB-3)

[0117] Pellets of a polyamide resin composition (AB-3) were obtained by the same treatment as in (AB-1), except that 100 g of sodium hydroxide, 100 g of ethylenediamine, and 4800 ml of water were added to the aqueous solution to form a 2% sodium hydroxide aqueous solution. The residual amount of silicone resin in the polyamide resin composition (AB-3) was 10.5 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0118] (Polyamide resin composition after separation of silicone resin from automobile airbag: AB-4)

[0119] The automobile airbag (S-2) was cut into 300 x 300 mm squares. A 15% sodium hydroxide aqueous solution was prepared by adding 750 g of sodium hydroxide, 100 g of ethylenediamine, and 4150 ml of water to an 8 L glass container. The slices were immersed in this solution, maintained at 60°C, and heated for 1 hour. This treatment is designated as treatment (X).

[0120] The above-described treatment (X) separated the silicone resin layer from the automotive airbag (S-2), yielding a treated sheet (i.e., a polyamide resin molded article in which the silicone resin layer was separated from the automotive airbag and the silicone resin remained on the surface). This sheet was chopped into 10×10 mm pieces and pelletized using a 70 mmφ single-screw extruder at a barrel temperature of 280°C and a discharge rate of 200 kg / hr. The resulting pellets were vacuum-dried at 80°C for at least 12 hours to yield pellets of a polyamide resin composition (AB-4). The residual silicone resin content of the polyamide resin composition (AB-4) was 1.4 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0121] (Polyamide resin composite after separation of silicone resin from polyamide resin composite: AB-5) [Note that in the present invention, the composition containing polyamide resin (A) and silicone resin (B) is represented by "AB", but for the sake of comparison with other Examples and Comparative Examples, the polyamide resin composite after separation of silicone resin from polyamide resin composite is also represented by "AB". The same applies to AB-7 described later.]

[0122] The polyamide resin composite (S-1) was cut into 300 x 300 mm squares. A 15% sodium hydroxide aqueous solution was prepared by adding 750 g of sodium hydroxide, 100 g of ethylenediamine, and 4150 ml of water to an 8 L glass container. The cut pieces were immersed in this aqueous solution, maintained at 60°C, and heated for 1 hour. This treatment was designated as treatment (X).

[0123] The silicone resin layer was separated from the polyamide resin composite (S-1) by the above treatment (X), yielding a treated sheet (i.e., a polyamide resin molded article in which the silicone resin layer was separated from the polyamide resin composite and the silicone resin remained on the surface). This sheet was cut into pieces of 10 x 10 mm and vacuum-dried at 80°C for at least 12 hours to yield a polyamide resin composite (AB-5). The amount of residual silicone resin in the polyamide resin composite (AB-5) was 3.0 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0124] (Polyamide resin composition obtained by pelletizing the polyamide resin composite: AB-6)

[0125] The polyamide resin composite (S-3) was chopped into 10 x 10 mm pieces and pelletized using a 70 mm diameter single-screw extruder at a barrel temperature of 280°C and a discharge rate of 200 kg / hr. The resulting pellets were vacuum dried at 80°C for at least 12 hours to obtain pellets of a polyamide resin composition (AB-6). The residual silicone resin content in the polyamide resin composition (AB-6) was 7.0 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0126] (Polyamide resin composite obtained by shredding the polyamide resin composite: AB-7)

[0127] The polyamide resin composite (S-3) was cut into pieces of 10 x 10 mm and vacuum dried at 80°C for at least 12 hours to obtain a polyamide resin composite (AB-7). The residual silicone resin content in the polyamide resin composite (AB-7) was 7.0 parts by weight per 100 parts by weight of the polyamide 66 resin.

[0128] [Examples 1 to 30, Comparative Examples 1 to 12]

[0129] According to the formulation shown in Tables 1 to 3, pellets of polyamide resin (A) containing silicone resin (B), silane coupling agent (C) and other raw materials were added from the raw material supply port upstream of the twin-screw extruder and melt-kneaded. The extruded strands were granulated to obtain a granular resin composition. The twin-screw extruder used was TEX30α manufactured by Japan Steel Works, Ltd., and melt-kneading was carried out under the conditions of a barrel temperature of 280°C, a screw speed of 200 rpm, and a discharge rate of 30 kg / hr. After the pellets of the obtained resin composition were vacuum-dried at 80°C for more than 12 hours, various properties were investigated by the above-mentioned evaluation method. The results are shown in Tables 1 to 3.

[0130] In Examples 1 to 30, even though the silicone resin was contained, the silicone resin was suppressed from falling off from the injection-molded articles and from adhering to the mold surface during molding, and the molded articles also had excellent mechanical properties.

[0131] In Comparative Examples 1 and 2, since the silicone content was greater than 12 parts, the silicone resin fell off from the injection-molded article and adhered significantly to the mold surface during molding.

[0132] In Comparative Examples 3, 4, 7, 8, 9, 10, 11, and 12, no silane coupling agent having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group was added. Therefore, the silicone resin tended to fall off from the injection-molded article and adhere to the mold surface during molding.

[0133] In Comparative Example 5, the amount of the silane coupling agent having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group was less than 0.01 parts by weight. Therefore, the silicone resin fell off from the injection-molded article and adhered significantly to the mold surface during molding.

[0134] In Comparative Example 6, the amount of the silane coupling agent having at least one functional group selected from isocyanate, epoxy, and acid anhydride groups exceeded 5 parts by weight, so gelation occurred during melt kneading, and particles could not be collected.

[0135]

[0136]

[0137]

[0138] Industrial Applicability

[0139] The polyamide resin composition of the present invention can be used as a polyamide resin composition in all fields where recycling is desired, especially in fields where material recycling is desired.

[0140] Explanation of symbols

[0141] 1 ball

[0142] 2 brackets

[0143] 3 Test pieces

Claims

1. A polyamide resin composition, wherein The present invention relates to 100 parts by weight of the polyamide resin (A), 0.01 to 12 parts by weight of the silicone resin (B), 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, and 0.01 to 5 parts by weight of an acid anhydride (E).

2. A molded article obtained by molding the polyamide resin composition according to claim 1.

3. A method for producing a polyamide resin composition, characterized in that: In producing the polyamide resin composition according to claim 1, the silicone resin layer is separated from a polyamide resin composite having a silicone resin layer formed on the surface of a polyamide resin molded body so that 0.01 to 12 parts by weight of the silicone resin layer remains relative to 100 parts by weight of the polyamide resin. The polyamide resin composite after the silicone resin layer is separated is temporarily converted into pellets or chips of composition (AB), or the polyamide resin composite after the silicone resin layer is separated is retained in its original form. 0.01 to 5 parts by weight of a silane coupling agent (C) having at least one functional group selected from an isocyanate group, an epoxy group, and an acid anhydride group, and 0.01 to 5 parts by weight of an acid anhydride (E) are melt-kneaded into the pellets or chips, or into the original form of the polyamide resin composite. 4 . A method for producing a molded article, comprising producing a polyamide resin composition by the method according to claim 3 , and molding the polyamide resin composition.

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