Polyamide resin composition, molded body, fluidity modifier, and binder resin

Abstract

The present invention relates to a polyamide resin composition which contains a polyamide resin (A), wherein: the polyamide resin (A) contains a polyamide resin (A-1) that has an alkyl group at an end and a polyamide resin (A-2) that has an arylene group at an end; and the terminal amino group concentration of the polyamide resin (A) is 0.10 μmol / g or less. The present invention also relates to a fluidity modifier for a thermoplastic resin (B), the fluidity modifier comprising only the polyamide resin (A). A molded body that contains the polyamide resin composition can contribute to the achievement of goals 9, 13, and the like of the sustainable development goals (SDGs) from the viewpoint of contributing to a reduction in resource usage by reducing the weight of the molded body.

Description

Polyamide resin composition, molded article, flowability modifier, and binder resin

[0001] The present invention relates to a polyamide resin composition, a molded article, a flowability modifier, and a binder resin.

[0002] Polyamide resins have excellent strength, toughness, chemical resistance, oil resistance, etc., and are used in various industrial fields as materials for injection molded articles and extrusion molded articles such as tubes, sheets, films, etc. In recent years, the development of applications for molded articles using polyamide resins has progressed, and the quality requirements have become increasingly sophisticated and diverse.

[0003] For example, magnetic material-resin composite materials comprising magnetic metal powder and a binder resin are known, and polyamide resins are widely used as the binder resin for such materials. Patent Documents 1 and 2 propose polyamide resins modified with monocarboxylic acids such as stearic acid as such polyamide resins. Patent Document 3 proposes a polyamide elastomer as the binder resin for such materials.

[0004] Japanese Patent Application Laid-Open No. 10-208918 Japanese Patent Application Laid-Open No. 2010-222394 International Publication No. 2023 / 181711

[0005] In order to use the polyamide resin as a magnetic material-resin composite material comprising a magnetic metal powder and a binder resin, the polyamide resin is required to have high fluidity as the binder resin. According to the findings of the inventors, it was found that the polyamide resins described in Patent Documents 1 to 3 need to be further improved in terms of fluidity.

[0006] An object of the present invention is to provide a polyamide resin composition having excellent flowability. Another object of the present invention is to provide a polyamide resin that functions as a flowability modifier for thermoplastic resins.

[0007] The present invention relates to the following items [1] to

[15] . [1] A polyamide resin composition comprising a polyamide resin (A), wherein the polyamide resin (A) comprises: a polyamide resin (A-1) having an alkyl group at a terminal; and a polyamide resin (A-2) having an arylene group at a terminal; and wherein the polyamide resin (A) has a terminal amino group concentration of 0.10 μmol / g or less. [2] The polyamide resin composition according to item [1], wherein the polyamide resin (A) has a number average molecular weight of 7,000 or more and less than 15,000. [3] The polyamide resin composition according to item [1] or [2], wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polyamide resin (A) is 1.75 to 2.20. [4] The polyamide resin composition according to any one of [1] to [3], wherein the relative viscosity of the polyamide resin (A) is 1.38 to 1.50, as measured at 25°C by dissolving 1 g of the polyamide resin (A) in 100 mL of 96% sulfuric acid in accordance with JIS K 6920. [5] The polyamide resin composition according to any one of [1] to [4], wherein the concentration of terminal carboxy groups in the polyamide resin (A) is 16.00 μmol / g or less. [6] The polyamide resin composition according to any one of [1] to [5], wherein the alkyl group in the polyamide resin (A-1) is a linear, branched, or cyclic alkyl group having 6 to 30 carbon atoms, which is unsubstituted or substituted with a hydroxy group. [7] The polyamide resin composition according to any one of [1] to [6], wherein the arylene group in the polyamide resin (A-2) is an unsubstituted or alkyl-substituted 1,2-phenylene group, a 1,2-naphthalenediyl group, a 2,3-naphthalenediyl group, or a 1,8-naphthalenediyl group. [8] The polyamide resin composition according to any one of [1] to [7], wherein the polyamide resin (A) contains a structural unit having 10 or more carbon atoms per amide group. [9] The polyamide resin composition according to any one of [1] to [8], wherein the polyamide resin (A) contains a polyamide resin (A-3) having an amino group at its terminal.

[10] A molded article comprising the polyamide resin composition according to any one of [1] to [9].

[11] A flowability modifier for a thermoplastic resin (B) consisting solely of a polyamide resin (A), wherein the polyamide resin (A) comprises: a polyamide resin (A-1) having an alkyl group at its terminal; and a polyamide resin (A-2) having an arylene group at its terminal; and wherein the polyamide resin (A) has a terminal amino group concentration of 0.10 μmol / g or less.

[12] The flowability modifier according to

[11] , wherein the polyamide resin (A) comprises a polyamide resin (A-3) having an amino group at its terminal.

[13] A thermoplastic resin composition comprising the flowability modifier according to

[11] or

[12] and a thermoplastic resin (B).

[14] A molded article comprising the flowability modifier according to any one of

[11] to

[13] .

[15] A binder resin for a magnetic metal powder (C), consisting solely of a polyamide resin (A), wherein the polyamide resin (A) comprises a polyamide resin (A-1) having an alkyl group at a terminal thereof and a polyamide resin (A-2) having an arylene group at a terminal thereof, and wherein the terminal amino group concentration of the polyamide resin (A) is 0.10 μmol / g or less.

[0008] According to the present invention, a polyamide resin composition having excellent flowability can be provided. Also, according to the present invention, a polyamide resin that functions as a flowability modifier for thermoplastic resins can be provided.

[0009] In this specification, the content of each component in a composition means the total amount of the multiple substances present in the composition when multiple substances corresponding to each component are present in the composition, unless otherwise specified. In this specification, the use of "to" to indicate a range of values ​​means that the values ​​before and after it are included as the lower and upper limits.

[0010] [Polyamide Resin Composition] The polyamide resin composition contains a polyamide resin (A). In the polyamide resin composition, the polyamide resin (A) contains a polyamide resin (A-1) having an alkyl group at a terminal and a polyamide resin (A-2) having an arylene group at a terminal, and the polyamide resin (A) has a terminal amino group concentration of 0.10 μmol / g or less.

[0011] In addition to having excellent flowability, the polyamide resin composition may also have excellent moldability. Here, the moldability is preferably injection moldability.

[0012] A molded article containing a polyamide resin composition can contribute to achieving Goals 9, 13, etc. of the SDGs (Sustainable Development Goals) from the viewpoint of contributing to a reduction in resource consumption by reducing the weight of the molded article.

[0013] [Embodiments of Polyamide Resin Composition] The polyamide resin composition is a composition containing two components, a polyamide resin (A-1) and a polyamide resin (A-2). The polyamide resin composition may consist of only the polyamide resin (A-1) and the polyamide resin (A-2).

[0014] The polyamide resin composition may consist solely of the polyamide resin (A). Here, the polyamide resin (A) may consist solely of the polyamide resin (A-1) and the polyamide resin (A-2), or may consist solely of the polyamide resin (A-1), the polyamide resin (A-2), and an additional polyamide resin other than the polyamide resin (A-1) and the polyamide resin (A-2).

[0015] [Polyamide Resin (A)] The polyamide resin (A) includes a polyamide resin (A-1) having an alkyl group at its terminal and a polyamide resin (A-2) having an arylene group at its terminal.

[0016] The polyamide resin portion other than the alkyl group in the polyamide resin (A-1) having an alkyl group at a terminal, and the polyamide resin portion other than the arylene group in the polyamide resin (A-2) having an arylene group at a terminal, each independently have a structure derived from an unmodified polyamide resin. Examples of unmodified polyamide resins include aliphatic polyamide resin (a).

[0017] <Aliphatic polyamide resin (a)> The aliphatic polyamide resin (a) is an aliphatic polyamide resin that does not have a group derived from an aromatic monomer in the main chain. Examples of the aliphatic polyamide resin (a) include aliphatic homopolyamide resin (a-1).

[0018] Aliphatic homopolyamide resin (a-1) refers to a polyamide resin containing one type of monomer component. Examples of the monomer component constituting the aliphatic polyamide resin include a combination of an aliphatic diamine and an aliphatic dicarboxylic acid, a lactam, or an aminocarboxylic acid. When the monomer component constituting the aliphatic polyamide resin is a combination of an aliphatic diamine and an aliphatic dicarboxylic acid, the combination of one type of aliphatic diamine and one type of aliphatic dicarboxylic acid is considered to be one type of monomer component.

[0019] The aliphatic diamine preferably has 2 to 20 carbon atoms, and more preferably has 4 to 12 carbon atoms. The aliphatic dicarboxylic acid preferably has 2 to 20 carbon atoms, and more preferably has 6 to 12 carbon atoms. The lactam preferably has 6 to 12 carbon atoms. The aminocarboxylic acid preferably has 6 to 12 carbon atoms.

[0020] Examples of aliphatic diamines include ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, heptadecanediamine, octadecanediamine, nonadecanediamine, and eicosanediamine. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedionic acid, dodecanedionic acid, tridecanedionic acid, tetradecanedionic acid, pentadecanedioic acid, hexadecanedioic acid, octadecanedioic acid, and eicosanedionic acid.

[0021] Examples of combinations of aliphatic diamines and aliphatic dicarboxylic acids include a combination of hexamethylenediamine and adipic acid, a combination of hexamethylenediamine and sebacic acid, and a combination of hexamethylenediamine and dodecanedioic acid, and equimolar salts of these combinations are preferably used.

[0022] Examples of lactams include ε-caprolactam, enantholactam, undecane lactam, dodecane lactam (laurolactam), α-pyrrolidone, α-piperidone, etc. Examples of aminocarboxylic acids include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid. From the viewpoint of productivity, the lactam is preferably ε-caprolactam, undecane lactam, or dodecane lactam.

[0023] Specific examples of the aliphatic homopolyamide resin (a-1) include polybutyrolactam (polyamide 4), polycaprolactam (polyamide 6), polyenantholactam (polyamide 7), polyundecane lactam (polyamide 11), polylauryllactam (polyamide 12), polytetramethylene adipamide (polyamide 46), polytetramethylene azelamide (polyamide 49), polytetramethylene sebacamide ( Polyamide 410), polytetramethylene dodecamide (polyamide 412), polypentamethylene adipamide (polyamide 56), polypentamethylene azelamide (polyamide 59), polypentamethylene sebacamide (polyamide 510), polypentamethylene dodecamide (polyamide 512), polyhexamethylene adipamide (polyamide 66), polyhexamethylene azelamide (polyamide 69), polyhex Poly(hexamethylene sebacamide) (polyamide 610), polyhexamethylene dodecamide (polyamide 612), polynonamethylene adipamide (polyamide 96), polynonamethylene azelamide (polyamide 99), polynonamethylene sebacamide (polyamide 910), polynonamethylene dodecamide (polyamide 912), polydecamethylene adipamide (polyamide 106), polydecamethylene azelamide (polyamide 10) 9), polydecamethylene decamide (polyamide 1010), polydecamethylene dodecamide (polyamide 1012), polydodecamethylene adipamide (polyamide 126), polydodecamethylene azelamide (polyamide 129), polydodecamethylene sebacamide (polyamide 1210), polydodecamethylene dodecamide (polyamide 1212), polydodecamethylene oxamide (polyamide 122), and the like.

[0024] <Characteristics of Unmodified Polyamide Resin> <Amino Group Concentration> The amino group concentration of the unmodified polyamide resin is not particularly limited, but from the viewpoint of productivity, it is preferably 20 to 110 μmol / g. The amino group concentration of the unmodified polyamide resin is a value determined by dissolving the unmodified polyamide resin in a mixed solvent of phenol / methanol = 9 / 1 (mass ratio) and performing neutralization titration. The amino group concentration of the unmodified polyamide resin can be adjusted by adding mono- or diamines and / or mono- or dicarboxylic acids during its production.

[0025] <Relative Viscosity of Unmodified Polyamide Resin> The relative viscosity of the unmodified polyamide resin is not particularly limited, but the relative viscosity measured at 25°C in 96% by mass sulfuric acid according to JIS K 6920 for a 1% by mass concentration of unmodified polyamide resin is preferably 1.80 to 5.00, and particularly preferably 2.00 to 4.50.

[0026] <<Method for Producing Unmodified Polyamide Resin>> Unmodified polyamide resins can be produced by using known polymerization methods such as melt polymerization, solution polymerization, and solid-state polymerization, and by repeating normal pressure, reduced pressure, and increased pressure operations. These polymerization methods can be used alone or in appropriate combination. Examples of production equipment include known polyamide production equipment, such as batch-type reactors, single- or multi-tank continuous reactors, tubular continuous reactors, and kneading reaction extruders such as single-screw kneading extruders and twin-screw kneading extruders.

[0027] [Polyamide Resin (A-1) Having an Alkyl Group at a Terminal] The polyamide resin (A-1) having an alkyl group at a terminal (also referred to as "polyamide resin (A-1)") is a polyamide resin obtained by modifying an amino group (i.e., -NH ２ The polyamide resin (A-1) is a polyamide resin in which an alkyl group (group) is modified with an alkyl group. That is, the polyamide resin (A-1) is a polyamide resin in which an alkyl group is bonded to a terminal via an amide bond. Specifically, the polyamide resin (A-1) having an alkyl group at a terminal is a modified polyamide resin having a structure in which the amino group at the terminal of an unmodified polyamide resin is replaced with an N-(alkylcarbonyl)amino group.

[0028] The alkyl group in the polyamide resin (A-1) is not particularly limited and can be linear, branched, or cyclic. The number of carbon atoms in the alkyl group can be 1 to 60, 3 to 50, or 6 to 30, and can be set appropriately depending on the structure of the alkyl group. The alkyl group can be unsubstituted or substituted with a hydroxy group. Therefore, the alkyl group in the polyamide resin (A-1) is preferably an unsubstituted or hydroxy-substituted, linear, branched, or cyclic alkyl group having 6 to 30 carbon atoms, more preferably an unsubstituted or hydroxy-substituted, linear or branched, alkyl group having 6 to 30 carbon atoms, and particularly preferably an unsubstituted or hydroxy-substituted, linear or branched, alkyl group having 10 to 20 carbon atoms.

[0029] The polyamide resin (A-1) can be used alone or in combination of two or more.

[0030] [Polyamide Resin (A-2) Having Arylene Groups at Terminals] Polyamide resin (A-2) (also referred to as "polyamide resin (A-2)") having arylene groups at terminals is a polyamide resin having an arylene group at terminals (i.e., -NH ２ The polyamide resin (A-2) is a polyamide resin in which an arylene group is bonded to the terminal via a cyclic imide bond. Specifically, the polyamide resin (A-2) is a modified polyamide resin having a structure in which the amino group at the terminal of an unmodified polyamide resin is replaced with a cyclic imide group having an aromatic group. Here, examples of the cyclic imide group having an aromatic group include a phthalimide group, a naphthalimide group, and the like, which may be unsubstituted or have a substituent.

[0031] The arylene group contained in the polyamide resin (A-2) is not particularly limited as long as it is a group that can bond with two carbonyl groups in the cyclic imide structure to form a cyclic imide structure. The arylene group contained in the polyamide resin (A-2) is preferably an unsubstituted or alkyl-substituted 1,2-phenylene group, 1,2-naphthalenediyl group, 2,3-naphthalenediyl group, or 1,8-naphthalenediyl group.

[0032] The polyamide resin (A-2) can be used alone or in combination of two or more.

[0033] [Additional Polyamide Resins] The polyamide resin (A) may contain an additional polyamide resin in addition to the polyamide resin (A-1) having an alkyl group at its terminal and the polyamide resin (A-2) having an arylene group at its terminal. Examples of the additional polyamide resin include a polyamide resin (A-3) having an amino group at its terminal. Here, examples of the polyamide resin (A-3) having an amino group at its terminal include those described above as unmodified polyamide resins.

[0034] <Preferred Aspects of Polyamide Resin (A)> The polyamide resin (A) preferably contains a structural unit having 10 or more carbon atoms per amide group. Specifically, the polyamide resins in the polyamide resin (A-1) having an alkyl group at a terminal, the polyamide resin (A-2) having an arylene group at a terminal, and the optional polyamide resin (A-3) having an amino group at a terminal each preferably contain a structural unit having 10 or more carbon atoms per amide group. The polyamide resin (A) more preferably contains a structural unit having 10 to 12 carbon atoms per amide group.

[0035] In the polyamide resin, the proportion of structural units having 10 or more carbon atoms per amide group is preferably 30 mol% or more, more preferably 50 mol% or more, and particularly preferably 80 mol% or more, relative to all structural units of the polyamide resin. The upper limit of the proportion of structural units having 10 or more carbon atoms per amide group in the polyamide resin is 100 mol%, i.e., all structural units of the polyamide resin have 10 or more carbon atoms per amide group.

[0036] <Characteristics of Polyamide Resin (A)> <Terminal Amino Group Concentration> The terminal amino group concentration of the polyamide resin (A) is 0.10 μmol / g or less. If the terminal amino group concentration of the polyamide resin (A) exceeds 0.10 μmol / g, the fluidity tends to be poor. The terminal amino group concentration of the polyamide resin (A) is measured by dissolving the polyamide resin in a mixed solution of phenol and methanol and titrating with 1 / 50 N hydrochloric acid. More specifically, it is measured by the method described in the Examples. Here, the terminal amino group concentration of the polyamide resin (A) refers to the amount of terminal amino groups of the polyamide resin (A) per gram of the polyamide resin (A). The terminal amino group concentration of the polyamide resin (A) is preferably 0.09 μmol / g or less. Furthermore, the terminal amino group concentration of the polyamide resin (A) is preferably 0.00 μmol / g or more, and particularly preferably 0.01 μmol / g or more.

[0037] <Terminal Carboxy Group Concentration> From the viewpoint of fluidity, the terminal carboxy group concentration of the polyamide resin (A) is preferably 16.00 μmol / g or less, more preferably 9.50 μmol / g or more and 16.00 μmol / g or less, and particularly preferably 11.00 μmol / g or more and 15.80 μmol / g or less. The terminal carboxy group concentration of the polyamide resin (A) is a value measured by dissolving the polyamide resin in benzyl alcohol and titrating with a 1 / 20N sodium hydroxide solution. More specifically, it is a value measured by the method described in the Examples. Here, the terminal carboxy group concentration of the polyamide resin (A) refers to the amount of terminal carboxy groups of the polyamide resin (A) per 1 g of the polyamide resin (A).

[0038] <Number Average Molecular Weight (Mn), Weight Average Molecular Weight (Mw), Ratio of Weight Average Molecular Weight (Mw) to Number Average Molecular Weight (Mn) (Mw / Mn)> The number average molecular weight of the polyamide resin (A) is preferably 7,000 or more but less than 15,000, more preferably 9,000 or more but less than 11,000, and particularly preferably 9,500 to 10,800. When the number average molecular weight of the polyamide resin (A) is within the above range, the flowability is better. The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polyamide resin (A) is preferably 1.75 to 2.20, more preferably 1.77 to 2.05, and particularly preferably 1.80 to 2.00. When the "Mw / Mn" of the polyamide resin (A) is within the above range, the flowability is better. The weight average molecular weight of the polyamide resin (A) is preferably within a range that satisfies the above-mentioned "Mw / Mn" ratio. The number average molecular weight and weight average molecular weight of the polyamide resin (A) are measured by gel permeation chromatography (GPC), and converted values ​​obtained from a calibration curve of a standard polystyrene prepared in advance can be used.

[0039] <<Relative Viscosity>> The relative viscosity of the polyamide resin (A), measured at 25°C by dissolving 1 g of the polyamide resin (A) in 100 mL of 96% sulfuric acid according to JIS K 6920, is preferably 1.50 or less, and particularly preferably 1.38 to 1.50. When the relative viscosity of the polyamide resin (A) is within this range, it tends to have excellent function as a flowability modifier, which will be described later.

[0040] [Method for Producing Polyamide Resin (A)] The method for producing the polyamide resin (A) is not particularly limited as long as the desired polyamide resin (A) can be obtained. For example, the following methods can be mentioned.

[0041] A first method for producing the polyamide resin (A) includes reacting an unmodified polyamide resin (i.e., a polyamide resin (A-3) having terminal amino groups) with a terminal modifier (i.e., an alkyl group-containing compound and an arylene group-containing compound). The terminal modifier has a group capable of reacting with the terminal amino group of the unmodified polyamide resin to form an amide bond or a cyclic imide bond.

[0042] Alkyl group-containing compounds include unsubstituted or hydroxy-substituted monocarboxylic acids, including aliphatic and alicyclic monocarboxylic acids.

[0043] Examples of the aliphatic monocarboxylic acid include acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, behenic acid, and montanic acid.

[0044] Examples of the alicyclic monocarboxylic acid include cyclohexanecarboxylic acid.

[0045] Examples of monocarboxylic acids substituted with a hydroxy group include 12-hydroxystearic acid.

[0046] The alkyl group-containing compound may be one type or two or more types.

[0047] Examples of the arylene group-containing compound include unsubstituted or alkyl-substituted aromatic dicarboxylic acid anhydrides, such as phthalic anhydride, 1,2-naphthalic anhydride, 2,3-naphthalic anhydride, and 1,8-naphthalic anhydride.

[0048] The arylene group-containing compound may be one type or two or more types.

[0049] In the first method for producing polyamide resin (A), the reaction of the alkyl group-containing compound and arylene group-containing compound, which are terminal modifiers, with the unmodified polyamide resin can be carried out by mixing the components. The reaction temperature is preferably 210 to 280°C, and more preferably 230 to 260°C. The reaction time is preferably 1 to 5 hours, and more preferably 1 to 3 hours. Examples of the production apparatus for polyamide resin (A) include those described above as the production apparatus for the unmodified polyamide resin.

[0050] In the first production method for polyamide resin (A), the amount of the terminal modifying agent used can be appropriately set depending on the concentration of terminal amino groups in the desired unmodified polyamide resin.

[0051] In the first production method of polyamide resin (A), the alkyl group-containing compound and arylene group-containing compound, which are terminal modifiers, may be reacted with the unmodified polyamide resin in the same order or in different orders.

[0052] From the viewpoint of efficiently obtaining a polyamide resin (A) having a preferred number average molecular weight, the first production method for the polyamide resin (A) is preferably a method comprising the following steps: Step 1) reacting an unmodified polyamide resin with an alkyl group-containing compound to obtain a polyamide resin (A-1) having an alkyl group at its terminal, and Step 2) reacting the alkyl group-containing polyamide resin (A-1) with an arylene group-containing compound to obtain a polyamide resin (A-2) having an arylene group at its terminal.

[0053] The second method for producing polyamide resin (A) includes reacting raw material monomers of unmodified polyamide resin with a terminal modifier (i.e., an alkyl group-containing compound and an arylene group-containing compound). In the second method for producing polyamide resin (A), the order in which the alkyl group-containing compound and the arylene group-containing compound, which are the terminal modifiers, are reacted with the unmodified polyamide resin may be simultaneous or different. From the viewpoint of efficiently obtaining a polyamide resin (A) with excellent fluidity, it is preferable that the order in which the alkyl group-containing compound and the arylene group-containing compound are reacted with the unmodified polyamide resin is simultaneous.

[0054] In the second production method of polyamide resin (A), the amount of terminal modifier used can be appropriately set depending on the amount of polyamide resin (A-1) having alkyl groups at the desired terminals and polyamide resin (A-2) having arylene groups at the terminals, depending on the terminal amino group concentration of the unmodified polyamide resin obtained from the raw material monomers.

[0055] In the second production method of the polyamide resin (A), the conditions for the reaction of each component may be the same as those described above in the first production method of the polyamide resin (A).

[0056] Furthermore, a third method for producing the polyamide resin (A) is the second method for producing a polyamide resin described below, which includes steps 3) and 4) in which a preferred terminal modifier is used.

[0057] The polyamide resin (A) may be used alone or in combination of two or more.

[0058] [Additional Components] The polyamide resin composition may contain additional components as long as the effects of the present invention are not impaired. Examples of additional components include a thermoplastic resin (B), a magnetic metal powder (C), and another component (D) (but not the thermoplastic resin (B) or the magnetic metal powder (C)). Therefore, it is preferable that the polyamide resin composition contains at least one component selected from the group consisting of a thermoplastic resin (B), a magnetic metal powder (C), and another component (D) (but not the thermoplastic resin (B) or the magnetic metal powder (C)).

[0059] <Thermoplastic Resin (B)> Examples of the thermoplastic resin (B) include acid-modified polyolefins, unmodified polyolefins, ionomers, ethylene / acrylic acid copolymers, ethylene / vinyl acetate copolymers, ethylene / acrylic acid ester copolymers, ethylene / methacrylic acid copolymers, polyesters, polyvinyl alcohols, polyamide resins (but not polyamide resins (A)), thermoplastic polyurethane resins, and the like, and acid-modified polyolefins are preferred.

[0060] Here, "polyamide resin (but not polyamide resin (A))" refers to a polyamide resin having structural units other than those of unmodified polyamide resins such as polyamide resin (A-1), polyamide resin (A-2), and polyamide resin (A-3) when the structural units of polyamide resin (A) are specified, and a polyamide resin other than polyamide resin (A-1), polyamide resin (A-2), and polyamide resin (A-3).

[0061] Examples of the polyolefin in the acid-modified polyolefin include (ethylene and / or propylene) / α-olefin copolymers and (ethylene and / or propylene) / (α,β-unsaturated carboxylic acid and / or α,β-unsaturated carboxylic acid ester) copolymers, and ethylene / α-olefin copolymers are preferred.

[0062] The (ethylene and / or propylene) / α-olefin copolymer is a polymer obtained by copolymerizing ethylene and / or propylene with an α-olefin having 3 or more carbon atoms. Examples of the α-olefins having 3 or more carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene.

[0063] The copolymer may also be one obtained by copolymerizing a polyene such as a non-conjugated diene. Examples of the non-conjugated diene include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,4-octadiene, 1,5-octadiene, 1,6-octadiene, 1,7-octadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 4-ethylidene-8-methyl-1,7-nonadiene, 4,8-dimethyl-1,4,8-decatriene (DMDT), and dicyclopentadiene. Examples of the olefin copolymer include ethylenediene, ethylenediene, cyclohexadiene, cyclooctadiene, 5-vinylnorbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropylidene-2-norbornene, 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, and 2-propenyl-2,5-norbornadiene.

[0064] The (ethylene and / or propylene) / (α,β-unsaturated carboxylic acid and / or α,β-unsaturated carboxylic acid ester) copolymer is a polymer obtained by copolymerizing ethylene and / or propylene with an α,β-unsaturated carboxylic acid and / or α,β-unsaturated carboxylic acid ester monomer. Examples of the α,β-unsaturated carboxylic acid monomer include acrylic acid and methacrylic acid. Examples of the α,β-unsaturated carboxylic acid ester monomer include methyl ester, ethyl ester, propyl ester, butyl ester, pentyl ester, hexyl ester, heptyl ester, octyl ester, nonyl ester, and decyl ester of an α,β-unsaturated carboxylic acid.

[0065] Compounds for acid-modifying polyolefins include carboxylic acids and derivatives thereof, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, mesaconic acid, citraconic acid, glutaconic acid, cis-4-cyclohexene-1,2-dicarboxylic acid, endo-bicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic acid, and metal salts of these carboxylic acids, monomethyl maleate, monomethyl itaconate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, hydroxyethyl acrylate, methyl methacrylate, 2-methyl-2-propanol, methyl meth ... -ethylhexyl, hydroxyethyl methacrylate, aminoethyl methacrylate, dimethyl maleate, dimethyl itaconate, maleic anhydride, itaconic anhydride, citraconic anhydride, endobicyclo-[2.2.1]-5-heptene-2,3-dicarboxylic anhydride, maleimide, N-ethylmaleimide, N-butylmaleimide, N-phenylmaleimide, acrylamide, methacrylamide, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate.

[0066] The acid-modified polyolefin is preferably an (ethylene and / or propylene) / α-olefin copolymer and an (ethylene and / or propylene) / (α,β-unsaturated carboxylic acid and / or α,β-unsaturated carboxylic acid ester) copolymer acid-modified with an unsaturated carboxylic acid or an acid anhydride thereof.

[0067] <Acid-modified amount> From the viewpoint of further enhancing adhesiveness, the acid-modified amount of the acid-modified polyolefin is preferably 8 to 100 μmol / g, more preferably 10 to 100 μmol / g, and particularly preferably 12 to 40 μmol / g. The acid-modified amount of the acid-modified polyolefin can be measured by titration. Specifically, the acid-modified amount of the acid-modified polyolefin can be measured by the method described in the examples.

[0068] The thermoplastic resin (B) may be used alone or in combination of two or more.

[0069] <Magnetic Metal Powder (C)> The magnetic metal powder (C) has the function of imparting magnetism and is not particularly limited as long as it is a known magnetic metal powder, and examples thereof include ferrite magnetic powder, alnico magnetic powder, rare earth magnetic powder, etc. Ferrite magnetic powders include barium ferrite magnetic powders such as iron oxide and barium carbonate; and strontium ferrite magnetic powders such as iron oxide and strontium carbonate. Alnico magnetic powders include alnico composed of nickel, aluminum, cobalt, iron, and copper; and alnico composed of nickel, aluminum, cobalt, iron, copper, and titanium. Rare earth magnetic powders include samarium cobalt, rare earth cobalt magnetic powders in which the cobalt component of samarium cobalt is substituted with copper, iron, titanium, zirconium, naphthium, niobium, tantalum, etc., and neodymium-iron-boron magnetic powder.

[0070] The average particle size of the magnetic metal powder (C) is preferably 0.1 to 300 μm, more preferably 0.1 to 200 μm, and even more preferably 0.5 to 100 μm. When the average particle size of the magnetic metal powder (C) is within the above range, the magnetic properties and mechanical properties of a molded article obtained from the polyamide resin composition may be improved.

[0071] In order to enhance compatibility with the polyamide resin composition, the magnetic metal powder (C) may be pretreated with a coupling agent or a surface modifier. The coupling agent and the surface modifier may each be used alone or in combination of two or more kinds.

[0072] Examples of coupling agents include conventional coupling agents such as silane-based, titanate-based, aluminum-based, and organic phosphorus compounds such as phosphite esters, as well as chromium-based and methacrylate-based coupling agents. Examples of surface modifiers include water glass, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, starch, polyvinyl alcohol, acrylic resin, epoxy resin, phenolic resin, polyvinyl acetate, polyurethane resin, epoxy compounds, isocyanate compounds, colloidal silica, colloidal alumina, fatty acids, and surfactants.

[0073] Among these, it is more preferable to treat the magnetic metal powder (C) with an amino group-containing silane compound and a titanate compound in order to improve compatibility with the polyamide resin.

[0074] Examples of amino group-containing silane compounds include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminodithiopropyltrihydroxysilane, γ-(polyethyleneamino)propyltrimethoxysilane, N-β-(aminopropyl)-γ-aminopropylmethyldimethoxysilane, N-(trimethoxysilylpropyl)-ethylenediamine, and γ-dibutylaminopropyltrimethoxysilane.

[0075] Examples of titanate compounds include isopropyl triisostearoyl titanate, isopropyl tri(N-aminoethyl) titanate, isopropyl tris(dioctyl pyrophosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraoctyl bis(ditridecyl phosphite) titanate, isopropyl trioctanoyl titanate, and isopropyl tridodecyl benzenesulfonyl titanate, isopropyl tri(dioctyl phosphate) titanate, bis(dioctyl pyrophosphate)ethylene titanate, isopropyl dimethacryl isostearoyl titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl phosphite) titanate, isopropyl tricumyl phenyl titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, isopropyl isostearoyl diacryl titanate, etc. Magnetic metal powder (C) can be used alone or in combination of two or more kinds.

[0076] <Other components (D) (however, not thermoplastic resin (B) and magnetic metal powder (C))> Other components (D) (however, not thermoplastic resin (B) and magnetic metal powder (C). hereinafter, also simply referred to as "other components (D)") include plasticizers, antioxidants, ultraviolet absorbers, heat resistance agents, foaming agents, weathering agents, crystal nucleating agents, crystallization accelerators, release agents, lubricants, antistatic agents, flame retardants, flame retardant assistants, stabilizers, pigments, dyes, and other functionality imparting agents. Examples of other components (D) include the components described in JP 2002-370551 A and JP 2023-089327 A. One or more types of other components (D) can be used.

[0077] [Content of each component] When the polyamide resin composition contains the thermoplastic resin (B), the content of the polyamide resin (A) relative to 100 parts by mass of the total of the polyamide resin (A) and the thermoplastic resin (B) is preferably 80 parts by mass or more and less than 100 parts by mass, and particularly preferably 90 parts by mass or more and 98 parts by mass or less.

[0078] When the polyamide resin composition contains magnetic metal powder (C), the content of magnetic metal powder (C) is preferably 70 parts by mass or more but less than 100 parts by mass, and particularly preferably 80 parts by mass or more but 95 parts by mass or less, relative to 100 parts by mass of the total of polyamide resin (A) and magnetic metal powder (C). When the content of polyamide resin (A) is within this range, the moldability of the polyamide resin composition and the residual magnetic flux density and mechanical properties of the molded product can be improved.

[0079] When the polyamide resin composition contains other component (D), the content of other component (D) is preferably 5.0 parts by mass or less, and particularly preferably 0.01 parts by mass or more and 3.0 parts by mass or less, per 100 parts by mass of the total of the polyamide resin (A) and other component (D).

[0080] [Method for producing polyamide resin composition] The method for producing the polyamide resin composition is not particularly limited, and for example, the following methods can be applied. Polyamide resin (A) and further components can be mixed using a commonly known melt kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. Specific mixing methods that are not limited include a method in which all raw materials are blended and then melt-kneaded using a twin-screw extruder; a method in which some raw materials are blended and then melt-kneaded, and then the remaining raw materials are blended and melt-kneaded; or a method in which some raw materials are blended and then the remaining raw materials are mixed using a side feeder during melt-kneading.

[0081] [Uses of Polyamide Resin Composition] The polyamide resin composition is not particularly limited and can be used to produce molded articles using known methods. Furthermore, the polyamide resin composition (preferably a polyamide resin composition consisting solely of polyamide resin (A)) has excellent flowability. Therefore, a polyamide resin composition consisting solely of polyamide resin (A) can be used as a flowability modifier for thermoplastic resin (B). Furthermore, a polyamide resin composition consisting solely of polyamide resin (A) can be used as a binder resin for magnetic metal powder (C).

[0082] [Molded Article] The molded article contains a polyamide resin composition. Examples of molded articles containing such a polyamide resin composition include the following first to fourth molded articles. The first molded article is a molded article of a polyamide resin composition consisting only of polyamide resin (A). The second molded article is a molded article of a polyamide resin composition consisting only of polyamide resin (A), thermoplastic resin (B), and, as an optional component, magnetic metal powder (C) and / or other component (D). The third molded article is a molded article of a polyamide resin composition consisting only of polyamide resin (A), magnetic metal powder (C), and, as an optional component, thermoplastic resin (B) and / or other component (D). The fourth molded article is a molded article of a polyamide resin composition consisting only of polyamide resin (A) and other component (D).

[0083] Examples of molding methods for the polyamide resin composition include injection molding, extrusion molding, blow molding, and rotational molding. Known methods can be used for these. Since the polyamide resin composition has excellent flowability, the molding method for the polyamide resin composition is preferably injection molding.

[0084] Molded articles containing the polyamide resin composition can be used for gears, pulleys, cams, bearings, cable housings, chassis, etc. of automobiles, machinery, electronic products, etc.; various magnetic products such as plastic magnets; light-reflective resin materials for light-emitting devices, packaging members for light-emitting semiconductors, conductive layer binder resins for conductive coating films, anchor coating resins for insulating substrates, resins for conductive rolls, members for sliding bearings, etc.

[0085] [Flowability Modifier] A further aspect of the present invention is a flowability modifier for a thermoplastic resin (B) consisting solely of a polyamide resin (A), wherein the polyamide resin (A) comprises a polyamide resin (A-1) having an alkyl group at a terminal thereof and a polyamide resin (A-2) having an arylene group at a terminal thereof, and wherein the polyamide resin (A) has a terminal amino group concentration of 0.10 μmol / g or less.

[0086] The term "flowability modifier consisting only of" means that it can be used independently as a flowability modifier. The terminal amino group concentration of the polyamide resin (A) is as described above. In the flowability modifier, the polyamide resin (A) may further contain a polyamide resin (A-3) having an amino group at its terminal.

[0087] Thermoplastic resins (B) used in injection molding (e.g., polyamide resins used in injection molding) are required to have moldability (e.g., the ability to be continuously and stably molded). Because polyamide resin compositions have excellent fluidity, they can be used as flowability modifiers for thermoplastic resins (B). By using a polyamide resin composition as a flowability modifier and adjusting the amount used, the melt viscosity of thermoplastic resin (B) can be freely set. This can improve the moldability, such as injection moldability, of a flowability-modified thermoplastic resin composition containing a flowability modifier and a thermoplastic resin (B) (hereinafter, sometimes simply referred to as a "thermoplastic resin composition").

[0088] The polyamide resin (A) used in the flowability modifier is as described above, including preferred embodiments thereof. The thermoplastic resin (B) is as described above.

[0089] [Thermoplastic resin composition] The thermoplastic resin composition contains a flowability modifier and a thermoplastic resin (B). The thermoplastic resin composition may contain additional components. Examples of the additional components include the magnetic metal powder (C) and the components described above as other components (D). The thermoplastic resin composition may not contain the magnetic metal powder (C).

[0090] The contents of the polyamide resin (A), the thermoplastic resin (B), the magnetic metal powder (C), and the other components (D) in the thermoplastic resin composition are as described above, including preferred embodiments. In addition, in the thermoplastic resin composition, the content of the flowability modifier relative to 100 parts by mass of the total of the flowability modifier and the thermoplastic resin (B) may be 1 part by mass or more but less than 50 parts by mass, or 3 parts by mass or more but 30 parts by mass or less.

[0091] [Uses of Thermoplastic Resin Composition] The thermoplastic resin composition can be formed into a molded article. A molded article containing the thermoplastic resin composition is a second molded article containing a polyamide resin composition. A molded article of the thermoplastic resin composition is also a molded article containing a flowability modifier. The molded article of the thermoplastic resin composition is as described above for the second molded article.

[0092] [Binder Resin] A further aspect of the present invention is a binder resin for a magnetic metal powder (C) consisting solely of a polyamide resin (A), wherein the polyamide resin (A) comprises a polyamide resin (A-1) having an alkyl group at a terminal thereof and a polyamide resin (A-2) having an arylene group at a terminal thereof, and wherein the terminal amino group concentration of the polyamide resin (A) is 0.10 μmol / g or less.

[0093] An example of a polyamide resin composition in which the polyamide resin (A) is used as a binder resin for the magnetic metal powder (C) is a polyamide resin composition containing the polyamide resin (A) and the magnetic metal powder (C) (hereinafter also referred to as the "second polyamide resin composition").

[0094] A polyamide resin composition consisting solely of polyamide resin (A) has excellent fluidity, and therefore tends to be able to contain a high concentration of magnetic metal powder (C) in the second polyamide resin composition. Furthermore, by including magnetic metal powder (C) in the second polyamide resin composition, magnetism is imparted to the second polyamide resin composition and its molded article. Examples of molded articles imparted with magnetism include plastic magnets.

[0095] The second polyamide resin composition may contain additional components, such as the thermoplastic resin (B) and the other components (D) described above. The second polyamide resin composition may not contain the thermoplastic resin (B).

[0096] The polyamide resin (A), thermoplastic resin (B), magnetic metal powder (C), other component (D), and their contents in the second polyamide resin composition are as described above for the polyamide resin composition, including preferred embodiments. The molded article of the second polyamide resin composition is as described above for the third molded article.

[0097] [Further Aspects of Polyamide Resin] [Second Polyamide Resin] A further aspect of the present invention relates to a polyamide resin (2) obtained by reacting a polyamide resin having an alkyl group with an arylene group-containing compound, wherein the polyamide resin (2) has a terminal amino group concentration of 0.10 μmol / g or less (hereinafter also referred to as "second polyamide resin").

[0098] The polyamide resin having an alkyl group is as described above for polyamide resin (A-1). The polyamide resin having an alkyl group is preferably a polyamide resin obtained by step 1) of the first production method of polyamide resin (A). The second polyamide resin is as described above for polyamide resin (A) except as described above.

[0099] [Method for producing second polyamide resin] The second polyamide resin is preferably obtained by a production method including the following steps 3) and 4): step 3) a step of reacting an unmodified polyamide resin (A-3) with an alkyl group-containing compound to obtain a polyamide resin (A-4) having an alkyl group at its terminal, and step 4) a step of reacting the polyamide resin (A-4) having an alkyl group at its terminal with an arylene group-containing compound to obtain a second polyamide resin.

[0100] In steps 3) and 4), the unmodified polyamide resin (A-3), alkyl group-containing compound, and arylene group-containing compound are as described above in the method for producing polyamide resin (A). In steps 3) and 4), the amounts of unmodified polyamide resin (A-3) and terminal modifier (alkyl group-containing compound and arylene group-containing compound) used can be appropriately set depending on the terminal amino group concentration of the second polyamide resin. In steps 3) and 4), the conditions for the reaction of each component can be the same as those described above in the first method for producing polyamide resin (A).

[0101] In step 3), the alkyl group-containing compound is preferably an unsubstituted or hydroxyl group-substituted monocarboxylic acid, and in step 4), the arylene group-containing compound is preferably an unsubstituted or alkyl group-substituted aromatic dicarboxylic acid anhydride.

[0102] When the monocarboxylic acid is used in step 3) and the aromatic dicarboxylic anhydride is used in step 4), the second polyamide resin is presumably obtained by the following mechanism: In other words, in step 3), the carboxy group of the monocarboxylic acid reacts with the amino group of the unmodified polyamide resin (A-3) to obtain "polyamide resin (A-4) having a carboxy group at one end and an alkyl group at the other end."

[0103] Then, in step 4), a portion of the amide bonds in the polyamide resin (A-4) is hydrolyzed to produce a "polyamide resin (A-5) having a carboxy group at one end and an alkyl group at the other end" and a "polyamide resin (A-6) having a carboxy group at one end and an amino group at the other end." The amino group in the polyamide resin (A-6) then reacts with the aromatic dicarboxylic anhydride to produce a "polyamide resin (A-7) having a structure in which the amino group at the end of an unmodified polyamide resin is replaced with a cyclic imide group having an aromatic group." Thus, the second polyamide resin comprises the polyamide resin (A-5) and the polyamide resin (A-7).

[0104] This can be confirmed by the following points regarding the polyamide resin obtained by the production method including steps 3) and 4). The first point is that the aromatic dicarboxylic acid anhydride, which is a terminal modifier, does not remain. The second point is that almost no amino groups remain at the terminals of the obtained polyamide resin. The third point can be confirmed by the fact that the measured terminal carboxyl group concentration of the obtained polyamide resin matches the terminal carboxyl group concentration estimated from the molecular weight, i.e., the aromatic dicarboxylic acid anhydride in the obtained polyamide resin does not undergo ring-opening. It can be assumed that the polyamide resins (A-5) and (A-7) are obtained through the above mechanism. Note that in step 4), a portion of the polyamide resin (A-4) may be contained in the second polyamide resin without undergoing hydrolysis. In this case, the second polyamide resin includes the polyamide resins (A-4), (A-5), and (A-7). In step 4), a portion of the polyamide resin (A-6) may be contained in the second polyamide resin without reacting with the aromatic dicarboxylic acid anhydride. In this case, the second polyamide resin contains the polyamide resin (A-5), the polyamide resin (A-6), and the polyamide resin (A-7). Furthermore, the second polyamide resin may contain the polyamide resin (A-4), the polyamide resin (A-5), the polyamide resin (A-6), and the polyamide resin (A-7).

[0105] The second polyamide resin is preferably polyamide resin (A). That is, the polyamide resin (A-5) and the polyamide resin (A-7) contained in the second polyamide resin are preferably polyamide resin (A-1) and polyamide resin (A-2) contained in polyamide resin (A), respectively. Here, when the second polyamide resin contains a portion of the polyamide resin (A-4), the polyamide resin (A-5) and the polyamide resin (A-4) correspond to polyamide resin (A-1). Furthermore, when the second polyamide resin contains a portion of the polyamide resin (A-6), the polyamide resin (A-6) corresponds to polyamide resin (A-3).

[0106] The present invention will be explained in more detail below with reference to Examples, Reference Examples, and Comparative Examples, but is not limited to the following examples as long as it does not depart from the gist of the present invention. Various evaluation methods and materials used are shown below.

[0107] [Measurement of Physical Properties of Polyamide Resin] (1) Relative Viscosity (ηrel) Relative viscosity (ηrel) was measured at 25° C. using an Ostwald viscometer in a 96% sulfuric acid solution with a polyamide resin concentration of 10 mg / mL according to JIS K 6920. A relative viscosity of 1.50 or less was determined to be “excellent in fluidity.”

[0108] (2) Terminal Amino Group Concentration A predetermined amount of polyamide resin was placed in a stopcocked Erlenmeyer flask, and 40 mL of a solvent, phenol / methanol (volume ratio 7 / 3), which had been prepared in advance, was added. The mixture was stirred with a magnetic stirrer to dissolve the polyamide resin, and titrated with 1 / 50 N hydrochloric acid using thymol blue as an indicator to determine the terminal amino group concentration (μmol / g).

[0109] (3) Terminal Carboxy Group Concentration A predetermined amount of polyamide resin was placed in a three-necked pear-shaped flask, and 40 mL of benzyl alcohol was added. The flask was then immersed in an oil bath set to 180°C under a nitrogen stream. The mixture was stirred and dissolved using a stirring motor attached to the top, and titration was carried out with a 1 / 20N sodium hydroxide solution using phenolphthalein as an indicator to determine the terminal carboxy group concentration (µmol / g).

[0110] (4) Number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) The number-average molecular weight (Mn) (g / mol) and weight-average molecular weight (Mw) (g / mol) of the polyamide resin were measured by gel permeation chromatography (GPC), and the converted values ​​obtained from a calibration curve of standard polystyrene prepared in advance were shown.

[0111] [Mechanical Properties] (1) Tensile Strength and Tensile Yield Strain Using pellets of the thermoplastic resin composition (polyamide resin for Reference Examples; the same applies below), Type A test pieces (ISO Type A) were prepared in accordance with ISO 294-1, and tensile tests were performed in an atmosphere of 23°C in accordance with ISO 527-1, 2. (2) Flexural Strength and Flexural Modulus Using pellets of the thermoplastic resin composition, Type B test pieces (ISO Type B) were prepared in accordance with ISO 294-1, and flexural tests were performed in an atmosphere of 23°C in accordance with ISO 178. (3) Charpy Impact Strength Using pellets of the thermoplastic resin composition, Type B test pieces (ISO Type B) were prepared in accordance with ISO 294-1, and V-notched in post-processing in accordance with ISO 179 / 1eA. Charpy impact tests were performed at 23°C with a hammer capacity of 15 J.

[0112] [Flow Modification] The flow modification of the thermoplastic resin composition was measured using a capillary rheometer (Capillograph 1D) manufactured by Toyo Seiki Seisaku-sho. The shape of the orifice used in the measurement was D = 1 mm, L / D = 10, and the barrel temperature was set to 190 ° C, 235 ° C, or 240 ° C. After the pellets of the thermoplastic resin composition were charged into the barrel and allowed to remain there for 5 minutes, the piston was pushed in at a predetermined speed to achieve a shear rate of 2,432 sec －１ The flow-improving property was evaluated by the shear viscosity value (Pa·s) at 100°C.

[0113] [Components Used] Terminal stearic acid modified polyamide 12 (1) (relative viscosity: 1.59, terminal amino group concentration: 1.25 μmol / g) Terminal stearic acid modified polyamide 12 (2) (relative viscosity: 1.68, terminal amino group concentration: 1.56 μmol / g) Terminal stearic acid modified polyamide 12 (3) (relative viscosity: 2.22, terminal amino group concentration: 2.15 μmol / g) Terminal stearic acid modified polyamide 12 (4) (relative viscosity: 1.93, terminal amino group concentration: 0.47 μmol / g) 12-aminododecanoic acid (manufactured by UBE Corporation) Polyamide 6 (1) (manufactured by UBE Corporation, relative viscosity: 1.96) Stearic acid (manufactured by NOF Corporation) Phthalic anhydride (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.)

[0114] <Example 1-1> (1) Production Example (1-1): Production Example of Terminal Stearic Acid Modified Polyamide 12 (1) 19.46 kg of laurolactam and 4.0 kg of degassed water were charged into a 70 L vessel (autoclave), and the vessel was purged with nitrogen. The vessel was then heated to 190 ° C. and stirred at this temperature to maintain a uniform reaction system. Next, the vessel's internal pressure was adjusted to 3.2 MPa, while the vessel's internal temperature was raised to 270 ° C. and maintained at this temperature for 5.5 hours. Thereafter, stirring was stopped, and the vessel was cooled while the pressure was released to normal pressure over approximately 2 hours. When the vessel's internal temperature reached 100 ° C. or below, 340 g of stearic acid was charged, the vessel was purged with nitrogen, and the vessel was then heated to 190 ° C. while adjusting the pressure to 0.05 MPa. The reaction system was then stirred at this temperature to maintain a uniform reaction system. Polymerization was then carried out under stirring for 3 hours. Nitrogen was then introduced into the vessel, and the strand was extracted from the lower nozzle of the vessel and cut into pellets, which were then dried under reduced pressure to obtain a terminal stearic acid-modified polyamide 12(1).

[0115] (2) Production Example (1-2): Production Example of Polyamide Resin (A) 19.84 kg of the terminally stearic acid-modified polyamide 12 (1) obtained in Production Example (1-1) above and 164 g of phthalic anhydride were charged into a 70 L vessel (autoclave). After replacing the atmosphere in the vessel with nitrogen, the vessel was heated to 190°C and stirred at this temperature to achieve a homogeneous reaction system. Next, the vessel was heated to 250°C while maintaining a sealed pressure. The pressure was then released to normal pressure, and polymerization was continued for 3 hours while adjusting the pressure to 0.05 MPaG. Nitrogen was then introduced into the vessel, and the strand was extracted from the bottom of the vessel and cut into pellets. The pellets were dried to obtain the polyamide 12 of Example 1-1. The obtained polyamide 12 of Example 1-1 was evaluated according to the above-mentioned [Measurement of Physical Properties of Polyamide Resin]. The results are shown in Table 1.

[0116] Example 1-2 A terminal stearic acid-modified polyamide 12 (1) was obtained in the same manner as in Production Example (1-1). Except for changing the amount of phthalic anhydride used to 184 g, a polyamide 12 of Example 1-2 was obtained in the same manner as in Production Example (1-2). The obtained polyamide 12 of Example 1-2 was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0117] <Comparative Example 1-1> A terminal stearic acid-modified polyamide 12(1) of Comparative Example 1-1 was obtained in the same manner as in Production Example (1-1). The terminal stearic acid-modified polyamide 12(1) of Comparative Example 1-1 obtained was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0118] <Example 2-1> (1) Production Example (2-1): Production Example of Terminal Stearic Acid-Modified Polyamide 12(2) A terminal stearic acid-modified polyamide 12(2) was obtained in the same manner as Production Example (1-1), except that the amount of laurolactam used was changed to 19.80 kg and the amount of stearic acid used was changed to 260 g.

[0119] (2) Production Example (2-2): Production Example of Polyamide Resin (A) The polyamide 12 of Example 2-1 was obtained in the same manner as in Production Example (1-2), except that the amount of the terminal stearic acid-modified polyamide 12 (2) obtained in Production Example (2-1) was changed to 19.80 kg and the amount of phthalic anhydride was changed to 224 g. The obtained polyamide 12 of Example 2-1 was evaluated in accordance with the above-mentioned [Measurement of physical properties of polyamide resin].

[0120] Example 2-2 A terminal stearic acid-modified polyamide 12 (2) was obtained in the same manner as in Production Example (2-1). Except for changing the amount of phthalic anhydride used to 244 g, a polyamide 12 of Example 2-2 was obtained in the same manner as in Production Example (2-2). The obtained polyamide 12 of Example 2-2 was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0121] Example 2-3 A terminal stearic acid-modified polyamide 12 (2) was obtained in the same manner as in Production Example (2-1). Except for changing the amount of phthalic anhydride used to 204 g, a polyamide 12 of Example 2-3 was obtained in the same manner as in Production Example (2-2). The obtained polyamide 12 of Example 2-3 was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0122] <Comparative Example 2-1> A terminal stearic acid-modified polyamide 12 (2) of Comparative Example 2-1 was obtained in the same manner as in Production Example (2-1). The terminal stearic acid-modified polyamide 12 (2) of Comparative Example 2-1 obtained was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0123] <Example 3-1> (1) Production Example (3-1): Production Example of Terminal Stearic Acid-Modified Polyamide 12(3) A terminal stearic acid-modified polyamide 12(3) was obtained in the same manner as Production Example (1-1), except that the amount of laurolactam used was changed to 19.80 kg and the amount of stearic acid used was changed to 30 g.

[0124] (2) Production Example (3-2): Production Example of Polyamide Resin (A) The polyamide 12 of Example 3-1 was obtained in the same manner as in Production Example (1-2), except that the amount of the terminal stearic acid-modified polyamide 12 (3) obtained in Production Example (3-1) was changed to 19.65 kg and the amount of phthalic anhydride was changed to 346 g. The obtained polyamide 12 of Example 3-1 was evaluated in accordance with the above-mentioned [Measurement of physical properties of polyamide resin].

[0125] <Comparative Example 3-1> A terminal stearic acid-modified polyamide 12 (3) of Comparative Example 3-1 was obtained in the same manner as in Production Example (3-1). The terminal stearic acid-modified polyamide 12 (3) of Comparative Example 3-1 obtained was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0126] <Example 4-1> (1) Production Example (4-1): Production Example of Terminal Stearic Acid-Modified Polyamide 12(4) A terminal stearic acid-modified polyamide 12(4) was obtained in the same manner as Production Example (1-1), except that the amount of laurolactam used was changed to 19.68 kg and the amount of stearic acid used was changed to 100 g.

[0127] (2) Production Example (4-2): Production Example of Polyamide Resin (A) The polyamide 12 of Example 4-1 was obtained in the same manner as in Production Example (1-2), except that the amount of the terminal stearic acid-modified polyamide 12 (4) obtained in Production Example (4-1) was changed to 19.69 kg and the amount of phthalic anhydride was changed to 310 g. The obtained polyamide 12 of Example 4-1 was evaluated in accordance with the above-mentioned [Measurement of physical properties of polyamide resin].

[0128] <Comparative Example 4-1> A terminal stearic acid-modified polyamide 12(4) of Comparative Example 4-1 was obtained in the same manner as in Production Example (4-1). The terminal stearic acid-modified polyamide 12(4) of Comparative Example 4-1 obtained was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0129] Example 5-1 (1) Production Example (5-1): Production Example of Polyamide Resin (A) 19.44 kg of 12-aminododecanoic acid, 390 g of stearic acid, and 170 g of phthalic anhydride were charged into a 70-liter vessel (pressure-resistant vessel). The vessel was then purged with nitrogen and heated to 190°C. The reaction system was stirred at this temperature to achieve a homogeneous state. The vessel was then heated to 250°C while adjusting the pressure to 0.5 MPaG. The pressure was then released to atmospheric pressure over approximately two hours, and polymerization was continued for three hours while adjusting the pressure to 0.05 MPaG. Nitrogen was then introduced into the vessel, and the resulting strand was extracted from the bottom of the vessel and cut into pellets. The pellets were dried to obtain polyamide 12(5) of Example 5-1. The resulting polyamide 12(5) of Example 5-1 was evaluated according to the above-described "Measurement of Physical Properties of Polyamide Resins."

[0130] Comparative Example 5-1 Pellets were obtained in the same manner as in Production Example (5-1), except that the amounts of 12-aminododecanoic acid and stearic acid used were changed to 19.61 kg and 390 g, respectively. The pellets were dried to obtain polyamide 12 of Comparative Example 5-1. The obtained polyamide 12 of Comparative Example 5-1 was evaluated according to the above-mentioned [Measurement of physical properties of polyamide resin].

[0131] Comparative Example 5-2 Pellets were obtained in the same manner as in Production Example (5-1), except that the amounts of 12-aminododecanoic acid and phthalic anhydride used were changed to 19.83 kg and 170 g, respectively. The pellets were dried to obtain polyamide 12 of Comparative Example 5-2. The obtained polyamide 12 of Comparative Example 5-2 was evaluated based on the above-mentioned [Measurement of physical properties of polyamide resin].

[0132] The results are summarized in Table 1. In Table 1, "(mass %)" in "Terminal Modifier" indicates the proportion (mass %) of the terminal modifier used relative to 100% by mass of the total of the polyamide resin or raw material monomer and the terminal modifier.

[0133]

[0134] It can be seen from Table 1 that the polyamide resin compositions of the Examples have excellent fluidity. That is, a comparison between Examples 1-1 and 1-2 shows that the relative viscosity decreased as the amount of phthalic anhydride used increased. The same was true for Examples 2-1 to 2-3.

[0135] It was also confirmed that the polyamide resins (A) obtained in Examples 1-1 to 5-1 contained no residual phthalic anhydride, which is a terminal modifier, and had almost no residual amino groups at the terminals. Furthermore, the terminal carboxyl group concentrations of the polyamide resins (A) obtained in Examples 1-1 to 5-1 and the terminal carboxyl group concentrations estimated from the number average molecular weights were nearly identical, confirming that the phthalic anhydride-derived structures contained in the polyamide resins were not ring-opened. Therefore, it is presumed that polyamide resins (A-1) and (A-2) are obtained by the following mechanism:

[0136] For example, in Production Example (1-2) of Example 1-1, some amide bonds of the terminal stearic acid-modified polyamide 12 (1) are hydrolyzed to produce a polyamide resin (A-5-1) having a carboxy group at one end and an alkyl group having 17 carbon atoms at the other end, and a polyamide resin (A-6-1) having a carboxy group at one end and an amino group at the other end. Then, the polyamide resin (A-6-1) reacts with phthalic anhydride to produce a polyamide resin (A-7-1) having a carboxy group at one end and an arylene group at the other end. This shows that the polyamide resin (A) obtained in Example 1-1 contains a polyamide resin (A-1) having an alkyl group at the end (i.e., polyamide resin (A-5-1)) and a polyamide resin (A-2) having an arylene group at the end (i.e., polyamide resin (A-7-1)). The same applies to Examples 1-2 to 5-1.

[0137] The compositions of Comparative Examples 1-1, 2-1, 3-1, and 4-1 did not contain a polyamide resin (A-2) having an arylene group at a terminal. The compositions of Comparative Examples 1-1, 2-1, 3-1, and 4-1 had poor fluidity. The compositions of Comparative Examples 5-1 and 5-2 contained a polyamide resin having a terminal amino group concentration of more than 0.10 μmol / g. The compositions of Comparative Examples 5-1 and 5-2 had poor fluidity.

[0138] In Examples 6-1 to 6-6 and Reference Examples 1-1 to 1-3, the polyamide resin composition of Example 2-1 was used as a flowability modifier for a thermoplastic resin. Terminal stearic acid-modified polyamide 12(1), terminal stearic acid-modified polyamide 12(3), or polyamide 6(1) was used as the thermoplastic resin.

[0139] Terminal stearic acid-modified polyamide 12(1), terminal stearic acid-modified polyamide 12(3), or polyamide 6(1) and the polyamide resin composition of Example 2-1 of the present invention were melt-kneaded at 200 to 260 ° C using a twin-screw kneader in the composition ratios (parts by mass) shown in Table 2 to obtain pellets of the flow-modified thermoplastic resin composition of Examples 6-1 to 6-6. Next, the obtained pellets of the thermoplastic resin composition of Examples 6-1 to 6-6 were injection-molded at a cylinder temperature of 290 ° C and a mold temperature of 80 ° C to produce various test pieces shown in Table 2, and the mechanical properties were evaluated. In addition, the shear viscosity was measured according to [Flow Modifier] using the obtained pellets of the thermoplastic resin composition of Examples 6-1 to 6-6.

[0140] <Reference Examples 1-1 to 1-3> Polyamide 12(1), polyamide 12(3), or polyamide 6(1) was melt-kneaded at 200 to 260°C using a twin-screw kneader in the composition ratios (parts by mass) shown in Table 2 to obtain polyamide resin pellets of Reference Examples 1-1 to 1-3. Next, the obtained polyamide resin pellets of Reference Examples 1-1 to 1-3 were injection-molded at a cylinder temperature of 290°C and a mold temperature of 80°C to produce various test pieces shown in Table 2, and the mechanical properties were evaluated. In addition, using the obtained polyamide resin pellets of Reference Examples 1-1 to 1-3, the shear viscosity was measured according to [Flow modifying property].

[0141] The results are summarized in Table 2.

[0142]

[0143] As shown in Table 2, the shear viscosity of the thermoplastic resin compositions of the Examples was lower than that of the thermoplastic resins of the Reference Examples. Therefore, Table 2 shows that the polyamide resin compositions of the Examples can improve the fluidity of thermoplastic resins. Table 2 also shows that the polyamide resin compositions of the Examples function as flowability modifiers for thermoplastic resins. Table 2 also shows that molded articles containing the polyamide resin compositions of the Examples can maintain the mechanical properties of molded articles using the polyamide resins of the Reference Examples.

Claims

1. A polyamide resin composition comprising a polyamide resin (A), wherein the polyamide resin (A) comprises a polyamide resin (A-1) having an alkyl group at a terminal thereof and a polyamide resin (A-2) having an arylene group at a terminal thereof, and wherein the concentration of terminal amino groups in the polyamide resin (A) is 0.10 μmol / g or less.

2. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) has a number average molecular weight of 7,000 or more but less than 15,000.

3. The polyamide resin composition according to claim 1, wherein the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the polyamide resin (A) is 1.75 to 2.

20.

4. The polyamide resin composition according to claim 1, wherein the relative viscosity of the polyamide resin (A), measured at 25°C in accordance with JIS K 6920 by dissolving 1 g of the polyamide resin (A) in 100 mL of 96% sulfuric acid, is 1.38 to 1.

50.

5. The polyamide resin composition according to claim 1, wherein the concentration of terminal carboxy groups in the polyamide resin (A) is 16.00 μmol / g or less.

6. The polyamide resin composition according to claim 1, wherein the alkyl group in the polyamide resin (A-1) is an unsubstituted or hydroxy-substituted, linear, branched or cyclic alkyl group having 6 to 30 carbon atoms.

7. The polyamide resin composition according to claim 1, wherein the arylene group contained in the polyamide resin (A-2) is an unsubstituted or alkyl-substituted 1,2-phenylene group, 1,2-naphthalenediyl group, 2,3-naphthalenediyl group, or 1,8-naphthalenediyl group.

8. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) contains a structural unit having 10 or more carbon atoms per amide group.

9. The polyamide resin composition according to claim 1, wherein the polyamide resin (A) comprises a polyamide resin (A-3) having an amino group at the terminal.

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

11. A flowability modifier for a thermoplastic resin (B) consisting solely of a polyamide resin (A), wherein the polyamide resin (A) comprises a polyamide resin (A-1) having an alkyl group at a terminal thereof and a polyamide resin (A-2) having an arylene group at a terminal thereof, and wherein the concentration of terminal amino groups in the polyamide resin (A) is 0.10 μmol / g or less.

12. The flowability improver according to claim 11, wherein the polyamide resin (A) comprises a polyamide resin (A-3) having an amino group at its terminal.

13. A thermoplastic resin composition comprising the flowability modifier according to claim 11 or 12 and a thermoplastic resin (B).

14. A molded body comprising the flowability improver according to claim 11 or 12.

15. A binder resin for magnetic metal powder (C), consisting solely of polyamide resin (A), wherein the polyamide resin (A) comprises polyamide resin (A-1) having an alkyl group at its terminal and polyamide resin (A-2) having an arylene group at its terminal, and wherein the terminal amino group concentration of the polyamide resin (A) is 0.10 μmol / g or less.

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