Resin composition, modifier for polyamide resin, and molded article

Abstract

One aspect of a resin composition according to the present invention comprises a polyamide resin (A), an acid-modified propylene-α-olefin copolymer (B), and an ethylene-α-olefin copolymer (C), wherein: with respect to 100 parts by mass of the total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C), the content of the polyamide resin (A) is 50-99 parts by mass, and the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) is 1-50 parts by mass; the mass ratio (acid-modified propylene-α-olefin copolymer (B) content / ethylene-α-olefin copolymer (C) content) of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) is 1 / 99 to 25 / 75; and the ethylene-α-olefin copolymer (C) is unmodified.

Description

Resin composition, modifier for polyamide resin, and molded article

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

[0002] Polyamide resins are widely used in the automotive, electrical, and electronic fields, taking advantage of their excellent properties as engineering plastics. Automotive and electrical components used in these fields often require impact resistance due to their functional needs. Particularly in the automotive field, there has been a strong demand for weight reduction in recent years to reduce fuel consumption, and thinner walls are being sought. However, thinning a molded product of a polyamide resin generally results in a rapid decline in impact resistance. A method of imparting impact resistance has been known in the past, which involves blending a modified polyolefin resin with a polyamide resin (Patent Documents 1 and 2).

[0003] JP-A-5-32886 Publication Special Publication No. 2021-503022

[0004] The modified polyolefin resins disclosed in Patent Documents 1 and 2 are modified ethylene-propylene polymers. The present inventors have confirmed that it is difficult to improve the impact resistance of molded articles containing polyamide resins without impairing the fluidity of the polyamide resin, leaving room for improvement. Therefore, the problem to be solved by the present invention is to provide a resin composition containing a polyamide resin that has a fluidity suitable for producing molded articles, and that the resulting molded articles have high impact resistance even when thin-walled. Another object of the present invention is to provide a polyamide resin modifier that, when blended with a polyamide resin, allows the polyamide resin to have a fluidity suitable for producing molded articles, while the resulting molded articles have high impact resistance even when thin-walled.

[0005] The present invention has the following aspects, for example: [1] A resin composition comprising a polyamide resin (A), an acid-modified propylene-α-olefin copolymer (B), and an ethylene-α-olefin copolymer (C), wherein the content of the polyamide resin (A) is 50 to 99 parts by mass and the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) is 1 to 50 parts by mass relative to a total of 100 parts by mass of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C), the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) (content of acid-modified propylene-α-olefin copolymer (B) / content of ethylene-α-olefin copolymer (C)) is 1 / 99 to 25 / 75, and the ethylene-α-olefin copolymer (C) is unmodified.

[0006] [2] The resin composition according to [1], wherein the polyamide resin (A) is an aliphatic polyamide.

[0007] [3] The resin composition according to [1] or [2], wherein the content of the polyamide resin (A) is 65 to 99 parts by mass, and the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) is 1 to 35 parts by mass, relative to a total of 100 parts by mass of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

[0008] [4] The resin composition according to any one of [1] to [3], wherein the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) is 1 / 99 to 15 / 85.

[0009] [5] The resin composition according to any one of [1] to [3], wherein the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) is 8 / 92 to 25 / 75.

[0010] [6] The resin composition according to any one of [1] to [5], wherein the acid-modified propylene-α-olefin copolymer (B) is a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene) modified with a polar compound.

[0011] [7] The resin composition according to any one of [1] to [6], wherein the ethylene-α-olefin copolymer (C) is a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms.

[0012] [8] The resin composition according to any one of [1] to [7], wherein the acid-modified propylene-α-olefin copolymer (B) satisfies the following requirements (Bi) and (B-ii): Requirement (Bi) is a melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg. ２．１６ Requirement (B-ii) The amount of acid modification is in the range of 0.1 to 5.0% by mass relative to 100% by mass of the acid-modified propylene-α-olefin copolymer (B).

[0013] [9] The resin composition according to any one of [1] to [8], wherein the ethylene / α-olefin copolymer (C) satisfies the following requirements (C-i) and (C-ii): Requirement (C-i) A melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg. ２．１６ Requirement (C-ii) The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ is in the range.

[0014]

[10] The resin composition according to any one of [1] to [9], wherein the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) is 5 / 95 to 18 / 82, and the acid-modified propylene-α-olefin copolymer (B) is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene) modified with a polar compound.

[0015]

[11] The resin composition according to any one of [1] to

[10] , wherein the content of the acid-modified propylene-α-olefin copolymer (B) is 0.4 parts by mass or more per 100 parts by mass of the total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

[0016]

[12] The resin composition according to any one of [1] to

[11] , further comprising a filler (D).

[0017]

[13] The resin composition according to

[12] , comprising 1 to 150 parts by mass of the filler (D) per 100 parts by mass in total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

[0018]

[14] A polyamide resin modifier comprising an acid-modified propylene-α-olefin copolymer (B') and an ethylene-α-olefin copolymer (C'), wherein the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B') to the content of the ethylene-α-olefin copolymer (C') (content of acid-modified propylene-α-olefin copolymer (B') / content of ethylene-α-olefin copolymer (C')) is 1 / 99 to 25 / 75, the acid-modified propylene-α-olefin copolymer (B') is a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene), which is modified with a polar compound, and the ethylene-α-olefin copolymer (C') is an unmodified copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

[0019]

[15] The polyamide resin modifier according to

[14] , which is for use in aliphatic polyamides.

[0020]

[16] The polyamide resin modifier according to

[14] or

[15] , wherein the acid-modified propylene / α-olefin copolymer (B') satisfies the following requirements (B'-i) and (B'-ii), and the ethylene / α-olefin copolymer (C') satisfies the following requirements (C'-i) and (C'-ii): Requirement (B'-i) is a melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg. ２．１６ Requirement (B'-ii): The amount of acid modification is in the range of 0.1 to 5.0% by mass relative to 100% by mass of the acid-modified propylene-α-olefin copolymer (B'). Requirement (C'-i): The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is in the range of 10 to 350 g / 10 min. ２．１６ Requirement (C'-ii) The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ is in the range.

[0021]

[17] The ethylene-α-olefin copolymer (C') is a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms, and is unmodified.

[14] The polyamide resin modifier according to any one of

[16] to

[17] .

[0022]

[18] The polyamide resin modifier according to any one of

[14] to

[17] , wherein the acid-modified propylene-α-olefin copolymer (B') is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene), modified with a polar compound.

[0023]

[19] A molded article comprising the resin composition according to any one of [1] to

[13] .

[0024] The resin composition of the present invention has a flowability suitable for producing molded articles, and the obtained molded articles have high impact resistance even when thinned. When the modifier for polyamide resins of the present invention is blended with a polyamide resin, the polyamide resin has a flowability suitable for producing molded articles, and the obtained molded articles have high impact resistance even when thinned.

[0025] Specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be implemented with appropriate modifications within the scope of the object of the present invention.

[0026] In this specification, the term "to" indicating a range of numerical values ​​is used to mean that the numerical values ​​before and after it are included as the lower and upper limits. In this specification, the term "to" indicating a range of numerical values ​​means that the units before and after it indicate the same units unless otherwise specified.

[0027] In the present specification, a combination of two or more preferred embodiments is a more preferred embodiment. Furthermore, unless otherwise specified, each component in the composition or each structural unit in the polymer may be contained alone or in combination of two or more types.

[0028] In this specification, the content of each component in a composition or each structural unit in a polymer means, when a plurality of substances or structural units corresponding to each component or each structural unit in a polymer are present in the composition, the total content of the corresponding substance present in the composition or each of the plurality of structural units present in the polymer, unless otherwise specified.

[0029] [Resin Composition] <Polyamide Resin (A)> The resin composition according to the present invention contains a polyamide resin (A). The polyamide resin (A) is not particularly limited, and conventionally known aliphatic polyamides, semi-aromatic polyamides, and aromatic polyamides can be used without limitation as long as the effects of the present invention are not impaired. For example, the polyamide resin (A) can be a melt-moldable polyamide resin obtained by a polycondensation reaction between an amino acid lactam or an organic diamine and an organic dicarboxylic acid.

[0030] Examples of the organic dicarboxylic acids include organic dicarboxylic acids having 4 to 12 carbon atoms, such as adipic acid, pimelic acid, suberic acid, phthalic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, phenylenedioxydiacetic acid, sebacic acid, and dodecanedioic acid, and organic dicarboxylic acids having 13 or more carbon atoms, such as oxydibenzoic acid, diphenylmethanedicarboxylic acid, diphenylsulfonedicarboxylic acid, and biphenyldicarboxylic acid. Examples of the organic diamines include organic diamines having 2 to 13 carbon atoms, such as hexamethylenediamine, octamethylenediamine, nonanediamine, octanediamine, decanediamine, undecanediamine, and dodecanediamine.

[0031] Examples of the polyamide resin (A) include polycondensates of organic dicarboxylic acids having 4 to 12 carbon atoms and organic diamines having 2 to 13 carbon atoms. Examples of the polycondensates include polyhexamethylene adipamide [polyamide 66], which is a polycondensate of hexamethylene diamine and adipic acid, polyhexamethylene azelamide [polyamide 69], which is a polycondensate of hexamethylene diamine and azelaic acid, polyhexamethylene sebacamide [polyamide 610], which is a polycondensate of hexamethylene diamine and sebacic acid, and polyhexamethylene dodecamethylol [polyamide 611], which is a polycondensate of hexamethylene diamine and dodecanedioic acid. polyamide [polyamide 612], polydecamethylenesebacamide [polyamide 1010], which is a polycondensation product of decamethylenediamine and sebacic acid, semi-aromatic polyamides (polyamide 6T, polyamide 9T, polyamide 10T, polyamide 11T), which are polycondensation products of aromatic dicarboxylic acids and aliphatic diamines, and polybis(4-aminocyclohexyl)methanedodecane, which is a polycondensation product of bis-p-aminocyclohexylmethane and dodecanedioic acid.

[0032] The polyamide resin (A) also includes a polycondensation product of an ω-amino acid. An example of the polycondensation product of an ω-amino acid is polyundecanoic amide [polyamide 11], which is a polycondensation product of ω-aminoundecanoic acid. Furthermore, the polyamide resin (A) also includes a ring-opening polymer of a lactam. An example of the ring-opening polymer of a lactam is polycapramide [polyamide 6], which is a ring-opening polymer of ε-aminocaprolactam, and polylauric lactam [polyamide 12], which is a ring-opening polymer of ε-aminolaurolactam.

[0033] As long as the polyamide resin (A) exhibits thermoplasticity, it may be modified with a small amount of a trivalent or higher polyhydroxy compound such as triol and tricarboxylic acid, and a polycarboxylic acid.From the viewpoint that the resin composition has a flowability suitable for producing a molded article, and the obtained molded article has high impact resistance even when thinned, the polyamide resin (A) is preferably an aliphatic polyamide, more preferably one or more polyamides selected from the group consisting of polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 612, polyamide 610 and polyamide 1010, and even more preferably one or more polyamides selected from the group consisting of polyamide 66, polyamide 69 and polyamide 6.

[0034] The polyamide resin (A) may be, for example, a polyamide resin produced from adipic acid, isophthalic acid, and hexamethylenediamine, or a blend of two or more polyamide resins, such as a mixture of polyamide 6 and polyamide 66. The raw material for the polyamide resin (A) may be a fossil fuel-derived raw material or a biomass-derived raw material. Furthermore, a fossil fuel-derived raw material and a biomass-derived raw material may be used in combination.

[0035] The spiral flow of the polyamide resin (A) measured with an injection molding machine is preferably greater than 600 mm, more preferably greater than 625 mm, and particularly preferably greater than 650 mm. For polyamide 66, the spiral flow measured at a dissolution temperature of 290°C and an injection pressure of 900 Bar is preferably within the above-mentioned range, and for polyamide 6, the spiral flow measured at a dissolution temperature of 260°C and an injection pressure of 900 Bar is preferably within the above-mentioned range. By using a polyamide resin (A) having a spiral flow within the above-mentioned range, the resin composition tends to exhibit the fluidity inherent to the polyamide resin (A), and the fluidity is not significantly impaired even when mixed with the acid-modified propylene-α-olefin copolymer (B) and ethylene-α-olefin copolymer (C) described below.

[0036] <Acid-Modified Propylene-α-Olefin Copolymer (B)> The resin composition contains an acid-modified propylene-α-olefin copolymer (B). The acid-modified propylene-α-olefin copolymer (B) is a copolymer obtained by modifying the propylene-α-olefin copolymer (b) described below with a polar compound. The raw materials for the acid-modified propylene-α-olefin copolymer (B), namely, propylene, an α-olefin other than propylene, and the polar compound, may be, for example, a monomer derived from a fossil fuel and / or a monomer derived from biomass, and these monomers may be used alone or in combination of two or more.

[0037] <Propylene / α-olefin copolymer (b)> The propylene / α-olefin copolymer (b) (hereinafter also referred to as "copolymer (b)") is a copolymer of propylene and an α-olefin other than propylene. The propylene / α-olefin copolymer (b) may be an isotactic polypropylene or a syndiotactic polypropylene. The propylene / α-olefin copolymer (b) may be a random copolymer or a block copolymer of propylene and an α-olefin other than propylene.

[0038] Examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, and 4-methyl-1-pentene. The α-olefin is preferably ethylene, 1-butene, 1-pentene, 1-hexene, and / or 4-methyl-1-pentene, more preferably ethylene, 1-butene, and / or 1-pentene, and even more preferably ethylene and / or 1-butene. The number of carbon atoms of the α-olefin is, for example, 2 to 20, preferably 2 to 10, more preferably 2 to 7, even more preferably 2 to 5, and particularly preferably 2 to 4.

[0039] The α-olefin may be one type alone or two or more types. The α-olefin is preferably one type or two or more types, more preferably one type or two types. In a preferred embodiment, the α-olefin is one type from the viewpoint of providing the resin composition with fluidity suitable for producing a molded article, and in another preferred embodiment, the α-olefin is two types from the viewpoint of providing the obtained molded article with high impact resistance, particularly high impact resistance at room temperature (e.g., 23°C), even when thin-walled.

[0040] The propylene / α-olefin copolymer (b) is, for example, a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene). In a preferred embodiment, the propylene / α-olefin copolymer (b) is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene), more preferably a copolymer of propylene and two α-olefins having 2 to 5 carbon atoms (excluding propylene), and even more preferably a copolymer of propylene and two α-olefins having 2 to 4 carbon atoms (excluding propylene).

[0041] When the propylene-α-olefin copolymer (b) is a copolymer of propylene and two kinds of α-olefins, examples of the copolymer (b) include a propylene-ethylene-1-butene copolymer, a propylene-ethylene-1-pentene copolymer, a propylene-ethylene-3-methyl-1-butene copolymer, a propylene-ethylene-1-hexene copolymer, a propylene-ethylene-4-methyl-1-pentene copolymer, a propylene-ethylene-1-octene copolymer, a propylene-1-butene-ethylene copolymer, a propylene-1-pentene-ethylene copolymer, a propylene-3-methyl-1-butene-ethylene copolymer, a propylene-1-hexene-ethylene copolymer, a propylene-4-methyl-1-pentene-ethylene copolymer, and a propylene-1-octene-ethylene copolymer.

[0042] When the propylene-α-olefin copolymer (b) is a copolymer of propylene and one type of α-olefin, the content of structural units derived from propylene in the propylene-α-olefin copolymer (b) is usually 51 mol% or more, preferably 70 mol% or more, more preferably 75 mol% or more, and even more preferably 80 mol% or more, based on 100 mol% of all structural units derived from polymerizable monomers. When the propylene-α-olefin copolymer (b) is a copolymer of propylene and two or more types of α-olefins, the content of structural units derived from propylene is the highest compared to the content of structural units derived from each of the α-olefins.

[0043] From the viewpoints of ensuring that the resin composition has a fluidity suitable for producing molded articles and that the resulting molded articles have high impact resistance even when thin-walled, the propylene / α-olefin copolymer (b) is preferably one or more copolymers selected from the group consisting of a high-α-olefin propylene / α-olefin copolymer (b1) (hereinafter also referred to as "Hα-PP(b1)") and a low-α-olefin propylene / α-olefin copolymer (b2) (hereinafter also referred to as "Lα-PP(b2)"). In a preferred embodiment, the propylene / α-olefin copolymer (b) comprises Hα-PP(b1), and is more preferably Hα-PP(b1).

[0044] Hα-PP (b1) is a copolymer of propylene and one or more α-olefins. The α-olefin is preferably an α-olefin having 2 to 20 carbon atoms (excluding propylene), more preferably an α-olefin having 2 to 15 carbon atoms, even more preferably an α-olefin having 2 to 10 carbon atoms, still more preferably ethylene, 1-butene, 1-hexene, 4-methyl-1-pentene, or 1-octene, and particularly preferably ethylene or 1-butene. These α-olefins may be used alone or in combination of two or more types. The α-olefin is preferably one type or two or more types. In one preferred embodiment, the α-olefin is one type, and in another preferred embodiment, two types are used.

[0045] When Hα-PP (b1) is a copolymer of propylene and one kind of α-olefin, Hα-PP (b1) is preferably a propylene-ethylene copolymer, a propylene-1-butene copolymer, a propylene-1-hexene copolymer, a propylene-4-methyl-1-pentene copolymer, or a propylene-1-octene copolymer, more preferably a propylene-ethylene copolymer or a propylene-1-butene copolymer, and even more preferably a propylene-ethylene copolymer.

[0046] When Hα-PP (b1) is a copolymer of propylene and two α-olefins, examples of Hα-PP (b1) include a propylene-ethylene-1-butene copolymer, a propylene-ethylene-1-pentene copolymer, a propylene-ethylene-3-methyl-1-butene copolymer, a propylene-ethylene-1-hexene copolymer, a propylene-ethylene-4-methyl-1-pentene copolymer, a propylene-ethylene-1-octene copolymer, a propylene-1-butene-ethylene copolymer, a propylene-1-pentene-ethylene copolymer, a propylene-3-methyl-1-butene-ethylene copolymer, a propylene-1-hexene-ethylene copolymer, a propylene-4-methyl-1-pentene-ethylene copolymer, and a propylene-1-octene-ethylene copolymer. Hα-PP (b1) is preferably a propylene-1-butene-ethylene copolymer.

[0047] The content of structural units derived from propylene in Hα-PP (b1) is usually 51 mol% or more and less than 95 mol%, and the content of structural units derived from α-olefins (excluding propylene) is usually more than 5 mol% and 49 mol% or less, based on 100 mol% of all structural units derived from polymerizable monomers. When Hα-PP (b1) is a copolymer of propylene and two or more α-olefins, the content of structural units derived from α-olefins means the total content of structural units derived from two or more α-olefins.

[0048] When Hα-PP (b1) is a copolymer of propylene and two types of α-olefins, the content of structural units derived from α-olefins having a smaller number of carbon atoms (excluding propylene) is, for example, more than 2 mol% and not more than 24 mol%, and the content of structural units derived from α-olefins having a larger number of carbon atoms (excluding propylene) is, for example, more than 3 mol% and not more than 25 mol%.

[0049] The content of structural units derived from propylene in Hα-PP (b1) is preferably 53 mol% or more and less than 95 mol%, more preferably 56 mol% or more and less than 95 mol%, and even more preferably 60 mol% or more and less than 95 mol%, and the content of structural units derived from α-olefins (excluding propylene) is preferably more than 5 mol% and not more than 47 mol%, more preferably more than 5 mol% and not more than 44 mol%, and even more preferably more than 5 mol% and not more than 40 mol%.

[0050] When Hα-PP (b1) is a copolymer of propylene and two types of α-olefins, the content of structural units derived from α-olefins having a smaller number of carbon atoms (excluding propylene) is preferably more than 2 mol% and not more than 23 mol%, more preferably more than 2 mol% and not more than 22 mol%, and even more preferably more than 2 mol% and not more than 19 mol%, and the content of structural units derived from α-olefins having a larger number of carbon atoms (excluding propylene) is preferably more than 3 mol% and not more than 24 mol%, more preferably more than 3 mol% and not more than 22 mol%, and even more preferably more than 3 mol% and not more than 21 mol%.

[0051] Lα-PP(b2) is a propylene-α-olefin random copolymer in which the content of structural units derived from propylene is 95 mol % or more of 100 mol % of all structural units derived from polymerizable monomers. Lα-PP(b2) is also referred to as "random polypropylene" hereinafter.

[0052] The content of the propylene-derived structural unit in the propylene-α-olefin copolymer (b) can be measured, for example, by using a nuclear magnetic resonance (NMR) measurement device (for example, JNM GX-400 manufactured by JEOL Ltd.) to dissolve 0.35 g of a sample in 2.0 mL of hexachlorobutadiene under heating, filtering the solution through a glass filter (G2), adding 0.5 mL of deuterated benzene, and then placing the tube in an NMR tube with an inner diameter of 10 mm. The tube is subjected to NMR analysis at a temperature of 120°C and for an accumulation of 8,000 cycles or more. １３ It can be calculated by measuring the C-NMR spectrum.

[0053] The propylene / α-olefin copolymer (b) may be one type or two or more types. The density of the propylene / α-olefin copolymer (b) is preferably 850 to 910 kg / m ３ , more preferably 854 to 910 kg / m ３ , more preferably 858 to 910 kg / m ３ The density of the propylene / α-olefin copolymer (b) can be measured at 25° C. in accordance with ASTM D1505.

[0054] The melt flow rate (MFR) of the propylene / α-olefin copolymer (b), measured in accordance with ASTM D1238 at 230°C under a load of 2.16 kg, is preferably in the range of 0.1 to 100 g / 10 min, more preferably 0.2 to 50 g / 10 min, and even more preferably 0.3 to 30 g / 10 min. When the MFR of the propylene / α-olefin copolymer (b) is in this range, the melt flow rate of the acid-modified propylene / α-olefin copolymer (B) can be set in a favorable range, so that the resin composition has fluidity suitable for producing molded articles, and the resulting molded articles tend to have high impact resistance even when thin-walled.

[0055] <Polar Compound> In the present invention, the polar compound is used to modify the propylene / α-olefin copolymer (b) to produce the acid-modified propylene / α-olefin copolymer (B).

[0056] The propylene-α-olefin copolymer (b) can be modified, for example, by reacting an unsaturated carboxylic acid and / or a derivative thereof with the base polymer. That is, the acid-modified propylene-α-olefin copolymer (B) is, for example, a polymer obtained by acid-modifying the propylene-α-olefin copolymer (b) with an unsaturated carboxylic acid and / or a derivative thereof. Examples of unsaturated carboxylic acids include maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid (a registered trademark of endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), acrylic acid, and methacrylic acid.

[0057] Examples of derivatives of unsaturated carboxylic acids include acid anhydrides, imide compounds, amide compounds, and ester compounds of the unsaturated carboxylic acids. Examples of imide compounds of unsaturated carboxylic acids include maleimide. Examples of acid anhydrides of unsaturated carboxylic acids include maleic anhydride and citraconic anhydride. Examples of ester compounds of unsaturated carboxylic acids include monomethyl maleate and glycidyl maleate. Among unsaturated carboxylic acids and their derivatives, unsaturated carboxylic acids and their acid anhydrides are preferred, with maleic acid, nadic acid, and their acid anhydrides being particularly preferred. When using unsaturated carboxylic acids and / or their derivatives, they may be used alone or in combination of two or more.

[0058] Acid modification can be carried out using a conventionally known method. Examples of acid modification methods include dissolving the propylene-α-olefin copolymer (b) as the base polymer in an organic solvent, adding an unsaturated carboxylic acid or a derivative thereof, and optionally a radical initiator such as an organic peroxide, to the resulting solution, and reacting for, for example, 0.5 to 15 hours, preferably 1 to 10 hours, at a temperature of, for example, 60 to 350°C, preferably 80 to 190°C. Another example of acid modification methods includes using an extruder or the like to add a propylene polymer, an unsaturated carboxylic acid or a derivative thereof, and optionally a radical initiator such as an organic peroxide, without a solvent, and reacting for, for example, 0.5 to 10 minutes at a temperature above the melting point of the propylene-α-olefin copolymer (b), preferably 120 to 350°C.

[0059] As the radical initiator, organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene are preferred.

[0060] The acid-modified propylene / α-olefin copolymer (B) is, for example, a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene) modified with a polar compound. In a preferred embodiment, the acid-modified propylene / α-olefin copolymer (B) is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene) modified with a polar compound.

[0061] The acid-modified propylene / α-olefin copolymer (B) is preferably a copolymer in which one or more copolymers selected from the group consisting of Hα-PP (b1) and Lα-PP (b2) are acid-modified, from the viewpoints of providing a resin composition with fluidity suitable for producing molded articles and of providing the resulting molded articles with high impact resistance even when thin-walled. In a preferred embodiment, the acid-modified propylene / α-olefin copolymer (B) is a copolymer in which a propylene / α-olefin copolymer (b) containing Hα-PP (b1) is acid-modified, and more preferably a copolymer in which Hα-PP (b1) is acid-modified.

[0062] The acid-modified propylene / α-olefin copolymer (B) preferably satisfies the following requirements (Bi) and (B-ii).

[0063] [Requirement (Bi)] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg ２．１６ ) is in the range of 10 to 350 g / 10 min. ２．１６ The MFR of the acid-modified propylene / α-olefin copolymer (B) is preferably in the range of 12 to 290 g / 10 min, more preferably 14 to 260 g / 10 min, even more preferably 16 to 250 g / 10 min, still more preferably 18 to 240 g / 10 min, and particularly preferably 160 to 240 g / 10 min. ２．１６ When the viscosity is within the above range, the resin composition has a flowability suitable for producing a molded article, and the obtained molded article tends to have high impact resistance even when made thin.

[0064] [Requirement (B-ii)] The amount of acid modification is in the range of 0.1 to 5.0% by mass, based on 100% by mass of the acid-modified propylene / α-olefin copolymer (B). The amount of acid modification is preferably 0.2 to 5% by mass, more preferably 0.3 to 5% by mass, and even more preferably 0.4 to 5% by mass. When the amount of acid modification is within the above range, the impact resistance of the obtained molded article is good. The amount of acid modification of the acid-modified propylene / α-olefin copolymer (B) can be measured by the method described in the Examples section.

[0065] <Ethylene / α-olefin copolymer (C)> The resin composition contains an ethylene / α-olefin copolymer (C). The ethylene / α-olefin copolymer (C) is a copolymer containing structural units derived from ethylene and structural units derived from an α-olefin.

[0066] Examples of the α-olefin include linear α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene, as well as branched α-olefins such as 2-butene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3-ethyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4-ethyl-1-hexene, and 3-ethyl-1-hexene. The α-olefin may be one type or two or more types. The ethylene-α-olefin copolymer (C) is, for example, a copolymer of ethylene and one type of α-olefin.

[0067] The α-olefin is preferably an α-olefin having 3 to 20 carbon atoms. From the viewpoints that the resin composition has fluidity suitable for producing a molded article and that the obtained molded article has high impact resistance even when thin-walled, the α-olefin is, in a preferred embodiment, an α-olefin having 4 to 20 carbon atoms, more preferably an α-olefin having 4 to 10 carbon atoms. In another preferred embodiment, the α-olefin is an α-olefin having 3 to 14 carbon atoms, more preferably an α-olefin having 3 to 10 carbon atoms, and from the viewpoint of easy availability, propylene, 1-butene, 1-hexene, or 1-octene is further preferred, 1-butene or 1-octene is even more preferred, and 1-butene is particularly preferred.

[0068] The content of structural units derived from ethylene in the ethylene-α-olefin copolymer (C) is the highest compared to the contents of structural units derived from other polymerizable monomers. For example, when the ethylene-α-olefin copolymer (C) is a copolymer of ethylene and one type of α-olefin, the content of structural units derived from ethylene is more than 50 mol% but less than 100 mol% of all structural units derived from polymerizable monomers (100 mol%), and the content of structural units derived from α-olefins is more than 0 mol% but less than 50 mol%.

[0069] The content of the structural units derived from ethylene is preferably in the range of 70 to 95 mol%, more preferably 73 to 93 mol%, even more preferably 76 to 91 mol%, even more preferably 78 to 89 mol%, and particularly preferably 80 to 87 mol%, relative to the total 100 mol% of the content of the structural units derived from ethylene and the content of the structural units derived from α-olefin. The content of the structural units derived from α-olefin is preferably in the range of 5 to 30 mol%, more preferably 7 to 27 mol%, even more preferably 9 to 24 mol%, even more preferably 11 to 22 mol%, and particularly preferably 13 to 20 mol%, relative to the total 100 mol% of the content of the structural units derived from ethylene and the content of the structural units derived from α-olefin.

[0070] The content (mol %) of the structural unit can be determined by the method described in the Examples section, for example. １３ It is calculated by measuring a C-NMR spectrum. When the content of structural units derived from an α-olefin in the ethylene / α-olefin copolymer (C) is within the above range, the resin composition has a fluidity suitable for producing a molded article, and the obtained molded article tends to have high impact resistance even when made thin. The ethylene and α-olefin that are the raw materials for the ethylene / α-olefin copolymer (C) may be, for example, a monomer derived from a fossil fuel and / or a monomer derived from biomass, and these monomers may be used alone or in combination of two or more.

[0071] The ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the ethylene / α-olefin copolymer (C) measured by gel permeation chromatography (GPC) is preferably in the range of 1.2 to 3.5, more preferably 1.4 to 3.0, even more preferably 1.6 to 2.4, and particularly preferably 1.8 to 2.2. By using an ethylene / α-olefin copolymer (C) having an Mw / Mn within the above range, the stickiness of a molded article obtained from the resin composition is suppressed. Mw / Mn can be calculated by performing GPC measurement using the method described in the Examples section.

[0072] The ethylene-α-olefin copolymer (C) is unmodified from the viewpoints that the resin composition has a fluidity suitable for producing a molded article and that the obtained molded article has high impact resistance even when thin-walled. The term "unmodified ethylene-α-olefin copolymer (C)" means that the chemical structure of the main chain or side chain of the ethylene-α-olefin copolymer (C) has not been modified by a chemical method. Examples of the chemical method include the introduction of a functional group, substitution, oxidation / reduction treatment, graft polymerization, and modifications by other chemical reactions. The term "unmodified ethylene-α-olefin copolymer (C)" means, for example, that the ethylene-α-olefin copolymer (C) has not been oxidized or modified with an unsaturated carboxylic acid or the like. The ethylene-α-olefin copolymer (C) has not been acid-modified with, for example, an unsaturated carboxylic acid and / or a derivative thereof. The ethylene-α-olefin copolymer (C) preferably satisfies the following requirements (C-i) and (C-ii):

[0073] [Requirement (C-i)] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg ２．１６ ) is in the range of 0.01 to 50 g / 10 min. ２．１６ The MFR of the ethylene / α-olefin copolymer (C) is preferably in the range of 0.03 to 46 g / 10 min, more preferably 0.06 to 43 g / 10 min, even more preferably 0.1 to 40 g / 10 min, and particularly preferably 0.3 to 38 g / 10 min. ２．１６When the viscosity of the resin composition containing the ethylene / α-olefin copolymer (C) is within the above range, the resin composition containing the ethylene / α-olefin copolymer (C) has a fluidity suitable for producing a molded article, and the obtained molded article tends to have high impact resistance even when thin-walled.

[0074] [Requirement (C-ii)] The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ The density is preferably in the range of 853 to 882 kg / m ３ , more preferably 856 to 879 kg / m ３ , more preferably 859 to 876 kg / m ３ When the density of the ethylene / α-olefin copolymer (C) is within the above range, a molded article obtained from the resin composition containing the ethylene / α-olefin copolymer (C) is lightweight and has excellent impact resistance even when thin-walled.

[0075] <Method for Producing Ethylene / α-Olefin Copolymer (C)> The ethylene / α-olefin copolymer (C) can be produced by a known method. The ethylene / α-olefin copolymer (C) can be prepared, for example, by copolymerizing ethylene and an α-olefin in the presence of a known catalyst capable of polymerizing olefins (e.g., a catalyst containing a solid titanium component and an organometallic compound as its main components, a vanadium-based catalyst comprising a soluble vanadium compound and an alkylaluminum halide compound, or a zirconium-based catalyst comprising a zirconium metallocene compound and an organoaluminum oxy compound). The catalyst is preferably a catalyst containing a metallocene compound as a catalyst component.

[0076] <Filler (D)> In a preferred embodiment, the resin composition further contains a filler (D). When the resin composition contains the filler (D), the molded article has higher rigidity and impact resistance. The filler (D) is not particularly limited, and various conventionally known inorganic fillers and organic fillers such as natural fibers can be used without limitation as long as the effects of the present invention are not impaired.

[0077] Examples of the filler (D) include fibrous, plate-like, powdery, and granular fillers.Specific examples of the filler (D) include glass fiber, glass flake, PAN-based and pitch-based carbon fiber, metal fibers such as stainless steel fiber, aluminum fiber, and brass fiber, organic fibers such as aromatic polyamide fiber, gypsum fiber, ceramic fiber, asbestos fiber, zirconia fiber, alumina fiber, silica fiber, titanium oxide fiber, silicon carbide fiber, rock wool, fibrous compounds such as potassium titanate whisker, barium titanate whisker, aluminum borate whisker, and silicon nitride whisker, as well as layered silicate minerals such as smectite, vermiculite, mica, talc, pyrophyllite, kaolin mineral, and serpentine mineral.As the filler (D), glass fiber and glass flake are preferred, and glass fiber is more preferred.The filler (D) may be used alone or in combination of two or more.

[0078] Glass fibers generally used for reinforcing resins can be used without any particular limitations. Examples of glass fibers include chopped strands of long and short fiber types, and milled fibers. The cross-sectional shape of the glass fibers may be a typical circle, or a non-circular shape such as a cocoon or oval.

[0079] When the cross section of the glass fiber is circular, the average diameter of the cross section is preferably in the range of 3 to 50 μm, more preferably 6 to 25 μm. When the average diameter of the glass fiber is equal to or greater than the lower limit, aggregation of the glass fibers is suppressed, and the contact area (surface area) with the polyamide resin (A) does not become too large, thereby suppressing a decrease in the fluidity of the resin composition. When the average diameter is equal to or less than the upper limit, sufficient rigidity and strength can be imparted to a molded article obtained from the resin composition.

[0080] When the cross-sectional shape of the glass fiber is non-circular, the average length of the longest diameter (major axis) of the cross section is preferably in the range of 3 to 120 μm, more preferably 5 to 60 μm. The average length of the shortest diameter (minor axis) is preferably in the range of 0.3 to 20 μm, more preferably 0.5 to 15 μm. The ratio of the major axis to the minor axis is preferably in the range of 1.2 to 10, more preferably 1.5 to 7.5. When the ratio of the major axis to the minor axis of the glass fiber having a non-circular cross section is in the above range, the resulting resin composition has excellent fluidity, and the molded article has excellent rigidity and impact resistance.

[0081] The average fiber length of the glass fiber is preferably in the range of 1 to 20 mm, more preferably 1.5 to 12 mm, and even more preferably 2 to 10 mm. By using glass fiber having an average fiber length in the above range, handling and kneading with the polyamide resin (A) are excellent, and a molded article obtained from the resin composition has sufficient rigidity and mechanical strength.

[0082] The surface of the glass fiber may be coated or subjected to bundling treatment with a known sizing agent. Examples of the sizing agent include coupling agents and bundling agents. Examples of the coupling agent include silane-based coupling agents and titanate-based coupling agents. Examples of the bundling agent include thermosetting resins such as urethane resins and epoxy resins, acrylic resins, and olefin-based resins.

[0083] As the coupling agent, a silane-based coupling agent such as aminosilane or epoxysilane is preferably used. As the binder, a urethane resin or an epoxy resin is preferably used from the viewpoint of affinity and adhesiveness with the polyamide resin (A) which is the matrix resin.

[0084] When the resin composition contains glass fibers, the average diameter and average fiber length of the glass fibers can be measured by the following method. First, the resin composition is dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), and then filtered to obtain a filtrate. Next, the filtrate is dispersed in water, and 300 glass fibers are randomly selected under an optical microscope (magnification: 50x), and the fiber length (Li) and diameter (Di) of each glass fiber are measured. The number of fibers having a fiber length of Li is designated as qi, and the weight average length (Lw) is calculated based on the following formula, which is the average fiber length of the glass fibers. Weight average length (Lw) = (Σqi × Li ２ ) / (Σqi×Li) Similarly, the number of fibers having a diameter Di is taken as ri, and the weight average diameter (Dw) is calculated based on the following formula, and this is taken as the average diameter of the glass fibers. Weight average diameter (Dw)=(Σri×Di ２ ) / (Σri × Di)

[0085] Examples of natural fibers include wood flour (made by peeling wood and processing it using a grinder), wood fiber, bamboo flour, bamboo fiber, isolated cellulose fiber, wool, agricultural fibers, wood pulp (wood-based pulp made by removing the bark from tree trunks, chipping the chips, and then subjecting them to mechanical, chemical, or combination treatments), other natural pulps, rayon, and cotton. Examples of agricultural fibers include wheat straw, rice straw, hemp, flax, kenaf, kapok, jute, ramie, sisal, henequen, corn fiber, coir, nut shells, and rice husks.

[0086] Examples of wood pulp include bleached softwood kraft pulp (NBKP) and bleached hardwood kraft pulp (LBKP). Other natural pulps include Manila hemp, paper mulberry, mitsumata, and gampi. Preferred natural fibers include wood flour, wood fiber, bamboo, bamboo fiber, cotton, and isolated cellulose fiber, with isolated cellulose fiber being more preferred from the viewpoint of suppressing variation in the mechanical strength of molded articles and improving the predictability of the strength of the resulting molded articles.

[0087] The cellulose fibers may be obtained from any material, such as wood, grass, pulp, and paper. The cellulose fibers obtained from trees may be obtained from any woody raw material, such as softwoods and hardwoods. The cellulose fibers obtained from grasses may be obtained from non-woody raw materials, such as grasses, mallows, legumes, and palms. The cellulose fibers obtained from pulps may be obtained from any pulp, such as cotton linter pulp obtained from the fibers surrounding cotton seeds.

[0088] The cellulose fibers obtained from paper may be cellulose fibers obtained from any paper such as newspaper, cardboard, magazines, and wood-free paper. As the cellulose fibers, cellulose fibers obtained from trees or grasses are preferred because they are easily available and inexpensive, and cellulose fibers obtained from trees are more preferred.

[0089] From the viewpoint of improving the mechanical strength and impact resistance of the molded body, the average degree of polymerization of the cellulose fibers is preferably from 50 to 2000, more preferably from 100 to 1500. The average degree of polymerization of the cellulose fibers can be measured according to the reduced specific viscosity method using a copper ethylenediamine solution described in Verification Test (3) of the "Japanese Pharmacopoeia, 15th Edition Commentary" (published by Hirokawa Shoten).

[0090] The cellulose fibers may be unmodified or unamorphized, or may be modified or amorphized. Modified cellulose fibers include, for example, fibers obtained by reacting hydroxyl groups of cellulose with ether compounds, alkyl chlorides, alkyl acid anhydrides, alkyl acid chlorides, etc. Amorphized cellulose fibers include, for example, fibers obtained by reducing the crystallinity of cellulose using a known method.

[0091] Cellulose fibers have polar functional groups such as hydroxyl groups, hydroxyl groups introduced by modification, carboxyl groups, amino groups, and quaternary ammonium groups.

[0092] <Resin Composition> The resin composition according to the present invention comprises a polyamide resin (A), an acid-modified propylene-α-olefin copolymer (B), and an ethylene-α-olefin copolymer (C). The mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) (content of acid-modified propylene-α-olefin copolymer (B) / content of ethylene-α-olefin copolymer (C)) is 1 / 99 to 25 / 75. In a preferred embodiment, the mass ratio is 2 / 98 to 23 / 77, more preferably 3 / 97 to 20 / 80, even more preferably 4 / 96 to 19 / 81, and particularly preferably 5 / 95 to 18 / 82. In another preferred embodiment, the mass ratio is 1 / 99 to 20 / 80, more preferably 1 / 99 to 18 / 82, and even more preferably 1 / 99 to 15 / 85. In another preferred embodiment, the mass ratio is 4 / 96 to 25 / 75, more preferably 8 / 92 to 25 / 75.

[0093] When the mass ratio of the content of the acid-modified propylene / α-olefin copolymer (B) to the content of the ethylene / α-olefin copolymer (C) in the resin composition is within the above range, it is presumed that the resin composition has fluidity suitable for producing a molded article, and the obtained molded article has high impact resistance even when thin-walled, for the following reasons.

[0094] Since the ethylene-α-olefin copolymer (C) is unmodified, the solubility parameters decrease in the following order: polyamide resin (A), acid-modified propylene-α-olefin copolymer (B), and ethylene-α-olefin copolymer (C). Therefore, when the mass ratio of the acid-modified propylene-α-olefin copolymer (B) to the ethylene-α-olefin copolymer (C) is within the above range, the phase structure of the resin composition can be a salami-like structure, in which the polyamide resin (A) constitutes a sea phase, the acid-modified propylene-α-olefin copolymer (B) constitutes an island phase, and the ethylene-α-olefin copolymer (C) constitutes a lake phase. The phase structure of the resin composition can also be a core-shell structure, in which the ethylene-α-olefin copolymer (C) constitutes a core portion and the acid-modified propylene-α-olefin copolymer (B) constitutes a shell portion. It is presumed that the formation of these phase structures in the resin composition improves the dispersibility of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) in the polyamide resin (A), the resin composition has fluidity suitable for producing molded articles, and the resulting molded articles have high impact resistance even when thin-walled. When the ethylene-α-olefin copolymer (C) is an acid-modified ethylene-α-olefin copolymer, the polyamide resin (A) reacts with the acid-modified ethylene-α-olefin copolymer, preventing the formation of the salami-like structure or core-shell structure, reducing the fluidity of the resin composition and making it difficult to obtain thin-walled molded articles.

[0095] The content of polyamide resin (A) is 50 to 99 parts by mass, and the total content of acid-modified propylene-α-olefin copolymer (B) and ethylene-α-olefin copolymer (C) is 1 to 50 parts by mass, relative to 100 parts by mass of the total of polyamide resin (A), acid-modified propylene-α-olefin copolymer (B), and ethylene-α-olefin copolymer (C). The content of polyamide resin (A) is preferably 65 to 99 parts by mass, more preferably 80 to 99 parts by mass, and even more preferably 84 to 99 parts by mass, and the total content of acid-modified propylene-α-olefin copolymer (B) and ethylene-α-olefin copolymer (C) is preferably 1 to 35 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 1 to 16 parts by mass.

[0096] When the content of the polyamide resin (A) and the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) in the resin composition are within the above ranges, the resin composition has a fluidity suitable for producing a molded article, and the obtained molded article tends to have high impact resistance even when thin-walled. From the same viewpoint, the content of the acid-modified propylene-α-olefin copolymer (B) is preferably 0.4 parts by mass or more per 100 parts by mass of the total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

[0097] When the resin composition contains a filler (D), the resin composition preferably contains 1 to 150 parts by mass, more preferably 5 to 135 parts by mass, even more preferably 10 to 120 parts by mass, and particularly preferably 15 to 100 parts by mass of the filler (D) per 100 parts by mass of the total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C). When the content of the filler (D) in the resin composition is within the above range, a molded article obtained from the resin composition tends to have rigidity and impact resistance.

[0098] The fact that the resin composition has a fluidity suitable for producing a molded article and that the resulting molded article has high impact resistance even when thinned means that the fluidity of the resin composition and the impact resistance of the molded article are compatible. In one aspect, this further means that the impact resistance of the resin composition is improved and the fluidity is not too low, compared to the polyamide resin (A) alone or the polyamide resin (A) containing the filler (D).

[0099] In the resin composition, for example, the rate of change in impact strength at 23°C relative to the polyamide resin (A) alone is 15% or more, the rate of change in impact strength at -40°C is 10% or more, and the rate of change in spiral flow length is -10 to 5%. The impact strengths and spiral flow length at 23°C and -40°C are measured by the methods described in the Examples section, and the respective rates of change are calculated by the methods described in the Examples section. The rate of change in impact strength at 23°C is preferably 30% or more, for example, 250% or less. The rate of change in impact strength at -40°C is preferably 20% or more, more preferably 40% or more, for example, 500% or less.

[0100] In the resin composition containing filler (D), for example, the rate of change in impact strength at 23°C relative to polyamide resin (A) containing filler (D) is 5% or more, the rate of change in impact strength at -40°C is 0.5% or more, and the rate of change in spiral flow length is -5 to 5%. The rate of change in impact strength at 23°C is preferably 15% or more, more preferably 30% or more, for example, 100% or less. The rate of change in impact strength at -40°C is preferably 10% or more, for example, 100% or less.

[0101] <Other Components> The resin composition may further contain other components in addition to the polyamide resin (A), acid-modified propylene-α-olefin copolymer (B), ethylene-α-olefin copolymer (C), and filler (D), provided that the object of the present invention is not impaired. Examples of the other components include polymers other than the polyamide resin (A), acid-modified propylene-α-olefin copolymer (B), and ethylene-α-olefin copolymer (C), weather resistance stabilizers, heat resistance stabilizers, ultraviolet absorbers, infrared absorbers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, lubricants, pigments, dyes, plasticizers, antioxidants, hydrochloric acid absorbers, antioxidants, crystal nucleating agents, antifungal agents, antibacterial agents, flame retardants, mold release agents, surfactants, and softeners. Examples of the other polymers include acid-modified propylene homopolymers, unmodified propylene homopolymers, and unmodified propylene-α-olefin copolymers. The other components may be one type or two or more types.

[0102] <Method for Producing Resin Composition> The resin composition can be produced by a known method for producing a resin composition, which involves melt-kneading or the like, by sequentially or simultaneously mixing the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), the ethylene-α-olefin copolymer (C), and any filler (D) and the other components as raw materials.

[0103] <Applications> The resin composition has a flowability suitable for producing molded articles, and the obtained molded articles have high impact resistance even when thin-walled. Therefore, the resin composition can be used to produce various molded articles.

[0104] <Pellets> The resin composition can be used to produce pellets. The pellets have, for example, a spherical, cylindrical, lenticular, or cubic shape. The pellets can be produced by known pelletizing methods. Examples of methods for producing pellets include a method in which the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), the ethylene-α-olefin copolymer (C), the optional filler (D), and the other components are uniformly melt-mixed, extruded using an extruder, and then hot-cut or strand-cut. The pellets produced by this method have, for example, a spherical, cylindrical, or lenticular shape. Cutting in this method may be performed either in water or in an air stream. Cubic pellets can be obtained, for example, by uniformly mixing the components, forming them into a sheet using a roll, or the like, and then using a sheet pelletizer. The pellets preferably have a length of 3 cm or less at their longest point.

[0105] The pellets can be used, for example, to produce a molded product, preferably a molded product by melt molding, which can be performed by any melt molding method, such as compression molding, injection molding, or extrusion molding.

[0106] <Injection Molded Article> An injection molded article can be obtained by injection molding the resin composition using a commonly used method.

[0107] The injection-molded articles are used in a wide range of applications, from household items such as daily necessities and recreational uses to general industrial applications and industrial goods. Examples of applications for the injection-molded articles include parts and components for various items such as home appliances, communication equipment, electrical and electronic equipment, automobiles, other vehicles, ships, aircraft, building materials, civil engineering materials, agricultural materials, power tools, food containers, films, sheets, and fibers. The injection-molded articles are particularly suitable for use as automobile parts and components. The injection-molded articles can also be used as parts for gasoline-powered vehicles, hybrid vehicles (HVs), plug-in hybrid vehicles (PHVs), electric vehicles (EVs), and fuel cell vehicles (FCVs). The injection-molded articles can also be used as parts for electric motorcycles.

[0108] Examples of the automotive parts and members include interior parts or members such as door trim, door module, instrument panel, center panel, roof panel, tailgate panel, accelerator and brake pedals, vertical exterior panels such as doors, fenders and tailgates, horizontal exterior panels such as hoods and roofs, engine compartment members such as air intakes, front-end modules and fan shrouds, and automotive electrical parts, including wire harness connectors, cable connectors, lamp sockets, on-board sensor switches, combination switches, batteries, motor mounts, power modules, converters, capacitors, insulators, motor terminal blocks and electric compressors.

[0109] [Modifier for Polyamide Resin] The modifier for polyamide resin according to the present invention comprises an acid-modified propylene / α-olefin copolymer (B') and an ethylene / α-olefin copolymer (C'). Examples of the acid-modified propylene / α-olefin copolymer (B') include copolymers similar to the acid-modified propylene / α-olefin copolymer (B) in the resin composition. Examples of the ethylene / α-olefin copolymer (C') include copolymers similar to the ethylene / α-olefin copolymer (C) in the resin composition.

[0110] The acid-modified propylene / α-olefin copolymer (B') is a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene) modified with a polar compound. Examples of the polar compound include the same polar compounds as those described for the resin composition. The acid-modified propylene / α-olefin copolymer (B') is preferably a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene) modified with a polar compound.

[0111] The acid-modified propylene / α-olefin copolymer (B') preferably satisfies the following requirements (B'-i) and (B'-ii): [Requirement (B'-i)] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is ２．１６ ) is in the range of 10 to 350 g / 10 min. ２．１６ is preferably in the range of 12 to 290 g / 10 min, more preferably 14 to 260 g / 10 min, even more preferably 16 to 250 g / 10 min, still more preferably 18 to 240 g / 10 min, and particularly preferably 160 to 240 g / 10 min.

[0112] [Requirement (B'-ii)] The amount of acid modification is in the range of 0.1 to 5.0% by mass, based on 100% by mass of the acid-modified propylene-α-olefin copolymer (B'). The amount of acid modification is preferably 0.2 to 5% by mass, more preferably 0.3 to 5% by mass, and even more preferably 0.4 to 5% by mass. When the amount of acid modification is within the above range, the impact resistance of the resulting molded article is good. The amount of acid modification can be measured by the method described in the Examples section.

[0113] The ethylene / α-olefin copolymer (C') is an unmodified copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. The ethylene / α-olefin copolymer (C') is preferably an unmodified copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms.

[0114] The ethylene / α-olefin copolymer (C') preferably satisfies the following requirements (C'-i) and (C'-ii): [Requirement (C'-i)] The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is ２．１６ ) is in the range of 0.01 to 50 g / 10 min. ２．１６ is preferably in the range of 0.03 to 46 g / 10 min, more preferably 0.06 to 43 g / 10 min, still more preferably 0.1 to 40 g / 10 min, and particularly preferably 0.3 to 38 g / 10 min.

[0115] [Requirement (C'-ii)] The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ The density is preferably in the range of 853 to 882 kg / m ３ , more preferably 856 to 879 kg / m ３ , more preferably 859 to 876 kg / m ３ is in the range.

[0116] The mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B') to the content of the ethylene-α-olefin copolymer (C') in the polyamide resin modifier (content of acid-modified propylene-α-olefin copolymer (B') / content of ethylene-α-olefin copolymer (C')) is 1 / 99 to 25 / 75. In a preferred embodiment, the mass ratio is 2 / 98 to 23 / 77, more preferably 3 / 97 to 20 / 80, even more preferably 4 / 96 to 19 / 81, and particularly preferably 5 / 95 to 18 / 82. In another preferred embodiment, the mass ratio is 1 / 99 to 20 / 80, more preferably 1 / 99 to 18 / 82, and even more preferably 1 / 99 to 15 / 85. In another preferred embodiment, the mass ratio is 4 / 96 to 25 / 75, more preferably 8 / 92 to 25 / 75.

[0117] The polyamide resin modifier is used, for example, by blending with a polyamide resin. Examples of the polyamide resin include the same resin as the polyamide resin (A) in the resin composition. The polyamide resin modifier is preferably used by blending with an aliphatic polyamide.

[0118] When a polyamide resin contains the polyamide resin modifier, the polyamide resin has a fluidity suitable for producing molded articles, and the resulting molded articles have high impact resistance even when thinned. Specifically, the impact resistance of the molded articles is improved while suppressing a decrease in the fluidity of the polyamide resin. For example, a polyamide resin containing the polyamide resin modifier exhibits a change in impact strength at 23°C of 15% or more, a change in impact strength at -40°C of 10% or more, and a change in spiral flow length of -10 to 5%, relative to the polyamide resin alone. The impact strength and spiral flow length at 23°C and -40°C are measured using the methods described in the Examples section, and the respective change rates are calculated using the methods described in the Examples section. The change in impact strength at 23°C is preferably 30% or more, for example, 250% or less. The change in impact strength at -40°C is preferably 20% or more, more preferably 40% or more, for example, 500% or less.

[0119] When the polyamide resin contains a filler, the polyamide resin containing the filler and the polyamide resin modifier has, for example, a change in impact strength at 23°C of 5% or more, a change in impact strength at -40°C of 0.5% or more, and a change in spiral flow length of -5 to 5%, relative to the polyamide resin containing the filler. The change in impact strength at 23°C is preferably 15% or more, more preferably 30% or more, for example, 100% or less. The change in impact strength at -40°C is preferably 10% or more, for example, 100% or less.

[0120] Examples of the filler include the same fillers as the filler (D) in the resin composition.

[0121] The amount of the polyamide resin modifier to be blended with the polyamide resin is preferably 1 to 100 parts by mass, more preferably 1 to 55 parts by mass, even more preferably 1 to 25 parts by mass, and particularly preferably 1 to 20 parts by mass, per 100 parts by mass of the polyamide resin, from the viewpoint of improving the impact resistance while suppressing a decrease in the fluidity of the polyamide resin.

[0122] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The components used in the following examples and comparative examples are as follows.

[0123] <Polyamide resin (A)> The following polyamide resins (A-1) and (A-2) were used as the polyamide resin (A). "Polyamide resin (A-1)": Polyamide 66 (manufactured by Toray Industries, Inc., trade name Amilan CM3007, spiral flow (melting temperature: 290°C, injection pressure: 900 Bar) over 700 mm) "Polyamide resin (A-2)": Polyamide 6 (manufactured by Toray Industries, Inc., trade name Amilan CM1007, spiral flow (melting temperature: 260°C, injection pressure: 900 Bar) over 700 mm)

[0124] <Acid-modified propylene / α-olefin copolymer (B)> The following polymers (B-1), (B-2), and (B-3) were used as the acid-modified propylene / α-olefin copolymer (B). - "Polymer (B-1)": Acid-modified random polypropylene obtained by acid-modifying random polypropylene (b-1) with maleic anhydride - "Polymer (B-2)": Acid-modified propylene / α-olefin copolymer obtained by acid-modifying propylene / α-olefin copolymer (b-2) with maleic anhydride - "Polymer (B-3)": Acid-modified propylene / α-olefin copolymer obtained by acid-modifying propylene / α-olefin copolymer (b-3) with maleic anhydride

[0125] The composition of the random polypropylene (b-1) measured by the physical property measurement methods described below was as follows: Type of α-olefin: ethylene, content of structural units derived from propylene: 97 mol%, content of structural units derived from α-olefin (ethylene): 3 mol%

[0126] The composition of the propylene-α-olefin copolymer (b-2) measured by the physical property measurement methods described below was as follows: Type of α-olefin: ethylene, Content of structural units derived from propylene: 84 mol%, Content of structural units derived from α-olefin (ethylene): 16 mol%

[0127] The composition of the propylene-α-olefin copolymer (b-3) measured by the physical property measurement methods described below was as follows: Types of α-olefins: ethylene and 1-butene, Content of structural units derived from propylene: 68 mol%, Content of structural units derived from α-olefin (ethylene): 13 mol%, Content of structural units derived from α-olefin (1-butene): 19 mol%

[0128] The acid modification in producing the polymers (B-1), (B-2) and (B-3) was carried out according to the method described in Example 1 of WO 2015 / 125802.

[0129] <Ethylene / α-olefin copolymer (C)> The following copolymers (C-1) to (C-5) were used as the ethylene / α-olefin copolymer (C): "Copolymer (C-1)": ethylene / 1-butene copolymer (EBR) "Copolymer (C-2)": ethylene / 1-butene copolymer (EBR) "Copolymer (C-3)": ethylene / 1-butene copolymer (EBR) "Copolymer (C-4)": ethylene / 1-butene copolymer (EBR) "Copolymer (C-5)": ethylene / 1-octene copolymer (EOR)

[0130] <Acid-modified ethylene / 1-butene copolymer> An acid-modified ethylene / 1-butene copolymer obtained by acid-modifying copolymer (C-1) with maleic anhydride was used. The acid modification amount was 1.0 mass %, MFR ２．１６ The viscosity was 3.6 g / 10 min. <Filler (D)> As the filler (D), the following glass fiber (D-1) was used. "Glass fiber (D-1)": glass fiber with a circular cross section, average diameter 10 μm, binder: urethane resin

[0131] The physical properties of the acid-modified propylene / α-olefin copolymer (B) and the ethylene / α-olefin copolymer (C) were evaluated by the following physical property measurement methods. The results of the physical property evaluation of the acid-modified propylene / α-olefin copolymer (B) and the ethylene / α-olefin copolymer (C) are shown in Tables 1 and 2.

[0132] [Density] Measured at 25°C in accordance with ASTM D1505.

[0133] [Content (Composition) of Structural Units Derived from Comonomers] The content of structural units derived from comonomers was measured using a nuclear magnetic resonance (NMR) measurement device (JNM GX-400 model, manufactured by JEOL Ltd.). 0.35 g of a sample was dissolved in 2.0 mL of hexachlorobutadiene by heating. After filtering the solution through a glass filter (G2), 0.5 mL of deuterated benzene was added, and the solution was placed in an NMR tube with an inner diameter of 10 mm and heated at 120°C. １３ C-NMR measurement was carried out. The number of accumulations was set to 8000 or more. １３ The contents (mol %) of structural units derived from ethylene and structural units derived from α-olefins other than ethylene in the ethylene / α-olefin copolymer (C), as well as the contents (mol %) of each structural unit in the random polypropylene (b-1), the propylene / α-olefin copolymer (b-2), and the propylene / α-olefin copolymer (b-3) were quantified by C-NMR spectrum.

[0134] [Molecular weight distribution (Mw / Mn)] Gel permeation chromatography (GPC) was performed to determine the polystyrene-equivalent molecular weight Mw / Mn of each fraction. ｉ－ＰＳｔ Next, M ｉ－ＰＳｔ , [η] ｉ－ＰＳｔ ×M ｉ－ＰＳｔ = [η] ｉ－ＥＰＲ ×M ｉ－ＥＰＲ [η] ｉ－ＰＳｔ = 1.37 x 10 －４ ×M ｉ－ＰＳｔ ０．６８６ , and [η] ｉ－ＥＰＲ = 7.2 x 10 －４ ×M ｉ－ＥＰＲ ０．６６７ Using the formula, the EPR-converted molecular weight Mｉ－ＥＰＲ The molecular weight distribution (Mw / Mn) was calculated using the EPR-converted molecular weight.

[0135] Gel permeation chromatography (GPC) was performed using a Waters gel permeation chromatograph Alliance GPC-2000 under the following conditions: Separation column: two TSKgel GNH6-HT columns, two TSKgel GNH6-HTL columns; Column size: diameter 7.5 mm, length 300 mm; Column temperature: 140°C; Mobile phase: o-dichlorobenzene (Fujifilm Wako Pure Chemical Industries, Ltd.); Antioxidant: BHT (Takeda Pharmaceutical Co., Ltd.) 0.025% by mass; Flow rate: 1.0 mL / min; Sample concentration: 15 mg / 10 mL; Sample injection volume: 500 μL; Detector: differential refractometer; Standard polystyrene: molecular weights Mw<1000 and Mw>4×10 ６ For the region where Mw is 1000 or less, the following is used: ６ For areas where

[0136] [MFR ２．１６ The melt flow rate (MFR) was measured in accordance with ASTM D1238 under the conditions of 190°C and a load of 2.16 kg. ２．１６ ) was measured.

[0137] [Acid-modified amount] The acid-modified amount (maleic anhydride-modified amount (mass%)) of the polymers (B-1), (B-2), and (B-3) was measured by FT-IR at a wave number of 1780 cm attributed to the carbonyl group. －１ The peak intensity was calculated from a separately prepared calibration curve.

[0138]

[0139]

[0140] [Example 1] A dry blend was prepared by mixing 97.0 parts by mass of the polyamide resin (A-1), which was polyamide 66, 0.6 parts by mass of the polymer (B-1), and 2.4 parts by mass of an ethylene-1-butene copolymer (C-3) using a Henschel mixer. This dry blend was then fed into the main inlet of a twin-screw extruder (L / D = 40, 30 mmφ) set at 285°C, and extruded at a screw rotation speed of 180 rpm and a discharge rate of 15 kg / hr to prepare pellets of the resin composition.

[0141] The resulting resin composition pellets were dried at 100°C for 24 hours, and then injection molded to prepare test pieces for physical property tests. The physical properties of the resin composition were evaluated using the test methods described below. The evaluation results are shown in Table 3.

[0142] [Examples 2 to 17, Examples 45 and 46, Comparative Examples 1 to 8, Reference Example 1] Production of pellets of the resin compositions, drying, preparation of test pieces, and evaluation of physical properties were carried out in the same manner as in Example 1, except that the formulations of the resin compositions were changed as shown in Tables 3 and 4. The evaluation results are shown in Tables 3 and 4.

[0143] [Examples 18 to 28, Reference Example 2] Production of pellets of the resin composition, drying and preparation of test pieces, and evaluation of physical properties were carried out in the same manner as in Example 1, except that the set temperature of the twin-screw extruder was adjusted to 245°C, the composition of the resin composition was changed as shown in Table 5, and the set temperature during fluidity evaluation was adjusted to 245°C. The results of each evaluation are shown in Table 5.

[0144]

[0145]

[0146]

[0147] A comparison of Example 3, Examples 5 and 6, Comparative Examples 1, 3 and 4, Comparative Example 7, and Reference Example 1 reveals that when the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) (content of acid-modified propylene-α-olefin copolymer (B) / content of ethylene-α-olefin copolymer (C)) is 1 / 99 to 25 / 75, the resin composition has fluidity comparable to that of the polyamide resin alone, i.e., fluidity suitable for producing a molded article, and the molded article has particularly high impact resistance.

[0148] Comparative Example 8, which used an acid-modified ethylene / 1-butene copolymer, had low fluidity, particularly compared to Examples 3 and 7-9.

[0149] In Examples 1 to 28 and 45 to 46, the change rate (23°C) was 15% or more, the change rate (-40°C) was 10% or more, and the change rate (fluidity) was -10 to 5%, so the resin composition had fluidity suitable for producing molded articles, and the molded articles had high impact resistance. On the other hand, in Comparative Examples 1 to 6 and 8, the change rate (23°C) was less than 15%, the change rate (-40°C) was less than 10%, or the change rate (fluidity) was less than -10% (fluidity decreased by more than 10%), so the resin composition did not have fluidity suitable for producing molded articles, or the molded articles did not have high impact resistance. In Comparative Example 7, the change rate (23°C) was less than 30%, so the molded articles were unlikely to have high impact resistance.

[0150] [Examples 29 to 43, Comparative Examples 9 to 10, Reference Example 3] Except for changing the composition of the resin composition as shown in Tables 6 to 7 and adding glass fiber (D-1) through the side inlet of the twin-screw extruder, pellets of the resin composition were produced, dried, test pieces were prepared, and the physical properties were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 6 to 7.

[0151]

[0152]

[0153] In Examples 29 to 43, the change rate (23°C) was 5% or more, the change rate (-40°C) was 0.5% or more, and the change rate (fluidity) was -5 to 5%, so the resin compositions had fluidity suitable for producing molded articles, and the molded articles had high impact resistance. On the other hand, in Comparative Examples 9 and 10, the change rate (23°C) was 5% or more, the change rate (-40°C) was 0.5% or more, but the change rate (fluidity) was less than -5% (fluidity decreased by more than 5%), so the resin compositions did not have fluidity suitable for producing molded articles.

[0154] [Physical Property Tests] (1) Charpy Impact Test Under the following test conditions, a hammer was swung down from the back of the notch of a fixed test specimen, and the impact strength was determined from the swing-up angle of the hammer after the test specimen broke and the lift-up angle of the hammer before the test. (Test Conditions) Test temperature: 23°C / -40°C, hammer capacity: 4 J, lift-up angle: 149.9, test specimen: notched, remaining width 8 mm, width 4 mm The impact strength at a test temperature of 23°C is also referred to as "impact strength (23°C)," and the impact strength at a test temperature of -40°C is also referred to as "impact strength (-40°C)."

[0155] (2) Rate of change in impact strength The rate of change in impact strength at a test temperature of 23°C was calculated using the following formula (1). The rate of change is also referred to as "rate of change (23°C)." Rate of change (23°C) (%) = (impact strength (23°C) - impact strength of Reference Example (23°C)) x 100 / impact strength of Reference Example (23°C) Formula (1) For the impact strength (23°C) of the Reference Example in Formula (1), the impact strength (23°C) of Reference Example 1 was used in Examples 1 to 17, Examples 45 to 46, and Comparative Examples 1 to 8, the impact strength (23°C) of Reference Example 2 was used in Examples 18 to 28, and the impact strength (23°C) of Reference Example 3 was used in Examples 29 to 43 and Comparative Examples 9 and 10.

[0156] The rate of change in impact strength at a test temperature of -40°C was calculated using the following formula (2). The rate of change is also referred to as "rate of change (-40°C)." Rate of change (-40°C) (%) = (impact strength (-40°C) - impact strength of Reference Example (-40°C)) x 100 / impact strength of Reference Example (-40°C) ... formula (2) For the impact strength (-40°C) of the Reference Example in formula (2), the impact strength (-40°C) of Reference Example 1 was used in Examples 1 to 17, Examples 45 to 46, and Comparative Examples 1 to 8, the impact strength (-40°C) of Reference Example 2 was used in Examples 18 to 28, and the impact strength (-40°C) of Reference Example 3 was used in Examples 29 to 43 and Comparative Examples 9 and 10.

[0157] (3) Flowability The flow distance (spiral flow length) was measured by injection molding using an injection molding machine with a cylinder temperature of 290°C, an injection pressure of 100 MPa, a mold temperature of 80°C, and a mold clamping force of 50 tonnes. In Examples 18 to 28 and Reference Example 2, the set temperature (cylinder temperature) during flowability evaluation was adjusted to 245°C.

[0158] (4) Rate of Change in Fluidity The rate of change in fluidity was calculated using the following formula (3). This rate of change is also referred to as "rate of change (fluidity)." Rate of change (fluidity) (%) = (spiral flow length - spiral flow length of Reference Example) x 100 / spiral flow length of Reference Example ... formula (3) With regard to the spiral flow length of the Reference Examples in formula (3), the spiral flow length of Reference Example 1 was used in Examples 1 to 17, Examples 45 and 46, and Comparative Examples 1 to 8, the spiral flow length of Reference Example 2 was used in Examples 18 to 28, and the spiral flow length of Reference Example 3 was used in Examples 29 to 43 and Comparative Examples 9 and 10.

Claims

1. A resin composition comprising a polyamide resin (A), an acid-modified propylene-α-olefin copolymer (B), and an ethylene-α-olefin copolymer (C), wherein the content of the polyamide resin (A) is 50 to 99 parts by mass relative to a total of 100 parts by mass of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C), the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) is 1 to 50 parts by mass, the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B) to the content of the ethylene-α-olefin copolymer (C) (content of acid-modified propylene-α-olefin copolymer (B) / content of ethylene-α-olefin copolymer (C)) is 1 / 99 to 25 / 75, and the ethylene-α-olefin copolymer (C) is unmodified.

2. The resin composition according to claim 1, wherein the polyamide resin (A) is an aliphatic polyamide.

3. The resin composition according to claim 1 or claim 2, wherein the content of the polyamide resin (A) is 65 to 99 parts by mass, and the total content of the acid-modified propylene-α-olefin copolymer (B) and the ethylene-α-olefin copolymer (C) is 1 to 35 parts by mass, relative to 100 parts by mass in total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

4. The resin composition according to claim 1 or claim 2, wherein the mass ratio of the content of the acid-modified propylene / α-olefin copolymer (B) to the content of the ethylene / α-olefin copolymer (C) is 1 / 99 to 15 / 85.

5. The resin composition according to claim 1 or claim 2, wherein the mass ratio of the content of the acid-modified propylene / α-olefin copolymer (B) to the content of the ethylene / α-olefin copolymer (C) is 8 / 92 to 25 / 75.

6. The resin composition according to claim 1 or 2, wherein the acid-modified propylene-α-olefin copolymer (B) is a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene) modified with a polar compound.

7. The resin composition according to claim 1 or 2, wherein the ethylene / α-olefin copolymer (C) is a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms.

8. The resin composition according to claim 1 or 2, wherein the acid-modified propylene-α-olefin copolymer (B) satisfies the following requirements (Bi) and (B-ii): Requirement (Bi) is that the melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is 0.015%. ２．１６ Requirement (B-ii) The amount of acid modification is in the range of 0.1 to 5.0% by mass relative to 100% by mass of the acid-modified propylene-α-olefin copolymer (B).

9. The resin composition according to claim 1 or 2, wherein the ethylene / α-olefin copolymer (C) satisfies the following requirements (C-i) and (C-ii): Requirement (C-i) The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is ２．１６ Requirement (C-ii) The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ is in the range.

10. The resin composition according to claim 1 or 2, wherein the mass ratio of the content of the acid-modified propylene / α-olefin copolymer (B) to the content of the ethylene / α-olefin copolymer (C) is 5 / 95 to 18 / 82, and the acid-modified propylene / α-olefin copolymer (B) is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene) modified with a polar compound.

11. The resin composition according to claim 1 or claim 2, wherein the content of the acid-modified propylene-α-olefin copolymer (B) is 0.4 parts by mass or more per 100 parts by mass of the total of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C).

12. The resin composition according to claim 1 or claim 2, further comprising a filler (D).

13. The resin composition according to claim 12, comprising 1 to 150 parts by mass of the filler (D) per 100 parts by mass of the polyamide resin (A), the acid-modified propylene-α-olefin copolymer (B), and the ethylene-α-olefin copolymer (C) combined.

14. A polyamide resin modifier comprising an acid-modified propylene-α-olefin copolymer (B') and an ethylene-α-olefin copolymer (C'), wherein the mass ratio of the content of the acid-modified propylene-α-olefin copolymer (B') to the content of the ethylene-α-olefin copolymer (C') (content of acid-modified propylene-α-olefin copolymer (B') / content of ethylene-α-olefin copolymer (C')) is 1 / 99 to 25 / 75, the acid-modified propylene-α-olefin copolymer (B') is a copolymer of propylene and one or more α-olefins having 2 to 20 carbon atoms (excluding propylene), which has been modified with a polar compound, and the ethylene-α-olefin copolymer (C') is an unmodified copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

15. The polyamide resin modifier according to claim 14, which is for use in aliphatic polyamides.

16. The polyamide resin modifier according to claim 14 or 15, wherein the acid-modified propylene / α-olefin copolymer (B') satisfies the following requirements (B'-i) and (B'-ii), and the ethylene / α-olefin copolymer (C') satisfies the following requirements (C'-i) and (C'-ii): Requirement (B'-i) is a melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg. ２．１６ Requirement (B'-ii): The amount of acid modification is in the range of 0.1 to 5.0% by mass relative to 100% by mass of the acid-modified propylene-α-olefin copolymer (B'). Requirement (C'-i): The melt flow rate (MFR) measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg is in the range of 10 to 350 g / 10 min. ２．１６ Requirement (C'-ii) The density measured at 25°C in accordance with ASTM D1505 is 850 to 885 kg / m ３ is in the range.

17. The polyamide resin modifier according to claim 14 or 15, wherein the ethylene / α-olefin copolymer (C') is a copolymer of ethylene and an α-olefin having 4 to 20 carbon atoms, and is unmodified.

18. The polyamide resin modifier according to claim 14 or 15, wherein the acid-modified propylene-α-olefin copolymer (B') is a copolymer of propylene and two α-olefins having 2 to 10 carbon atoms (excluding propylene) modified with a polar compound.

19. A molded article comprising the resin composition according to claim 1 or claim 2.

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