Graft copolymer

Abstract

To provide a silane-modified polyolefin that has a main chain part derived from an ethylene-α-olefin copolymer (A) and a graft part derived from an organic silicon compound (B) having one or more unsaturated groups and can be emulsified alone.SOLUTION: A graft copolymer (X) has a main chain part derived from an ethylene-α-olefin copolymer (A), a graft part derived from an organic silicon compound (B) having one or more unsaturated groups, and a graft part derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a graft copolymer having a main chain composed of an ethylene-based polymer.

Background Art

[0002] Graft copolymers having a main chain portion derived from an olefin-based polymer such as polyethylene, polypropylene, or an ethylene-α-olefin copolymer and a graft portion derived from an organosilicon compound (typically an unsaturated silane compound) are being studied for various applications such as resin modifiers by utilizing the characteristics of the functional groups contained in the graft portion. For example, in Patent Document 1, as a copolymer suitable for applications such as a modifier, a specific graft copolymer grafted with an organosilicon compound (unsaturated silane compound) at a specific graft ratio with respect to a specific ethylene-α-olefin random copolymer is being studied for applications such as a modifier for resins or rubbers.

[0003] In addition, for the purpose of improving the adhesion to highly polar materials, etc., graft copolymers containing a main chain portion derived from the olefin-based polymer and a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative have been studied for various applications. For example, as an example, it is being studied as a sizing agent (bundling agent) for improving the strength of fibers.

[0004] For example, in Patent Document 2, an aqueous dispersion containing a propylene-based resin containing a specific carboxylate is being studied as an aqueous dispersion for fiber treatment.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The graft copolymer having a main chain portion derived from the above-described ethylene-α-olefin copolymer and a graft portion derived from an organosilicon compound (for example, an organosilicon containing one or more unsaturated groups, typically an unsaturated silane compound) is expected to be used as a material for sizing agents for glass fibers due to the affinity of the functional groups derived from the organosilicon compound in the graft portion for glass fibers. Sizing agents are usually often used as emulsions, and it is also desirable to emulsify a graft copolymer containing only functional groups derived from an organosilicon compound in the graft portion into an emulsion. However, it is difficult for a graft copolymer having only functional groups derived from an organosilicon compound (typically an unsaturated silane compound) as a graft portion to be stably emulsified alone. [[ID=⑧]] [[ID=⑨]]

[0007] [[ID=⑩]] [[ID=⑪]]Therefore, as one means for producing a stable emulsion, a graft copolymer having only functional groups derived from an organosilicon compound (typically an unsaturated silane compound) as a graft portion is mixed with a graft copolymer having a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (for example, maleic anhydride) (for example, a graft copolymer having a main chain portion derived from an ethylene-α-olefin copolymer (A) and a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative), and this is emulsified. [[ID=⑫]] [[ID=⑬]]

[0008] [[ID=⑭]] [[ID=⑮]]However, when the above-described mixture is used, the concentration of the functional groups derived from the organosilicon compound contained in the graft portion with respect to the main chain portion derived from the ethylene-α-olefin copolymer contained in the mixture decreases. Therefore, there is a risk that the effect derived from the functional groups derived from this organosilicon compound will decrease. For this reason, a graft copolymer that can be emulsified has been desired even when it is a graft copolymer having a graft portion derived from an organosilicon compound and a main chain portion derived from an ethylene-α-olefin copolymer alone. [[ID=⑯]]

[0009] The present invention aims to provide a graft copolymer having a main chain portion derived from an ethylene·α-olefin copolymer (A) and a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, which can be emulsified alone.

Means for Solving the Problems

[0010] As a result of the inventors' further investigation, it has been found that the above problems can be solved by a graft copolymer having a main chain portion derived from an ethylene·α-olefin copolymer (A), a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, and a graft portion derived from a specific unsaturated compound, and thus the present invention has been completed.

[0011] That is, the present invention has, for example, the following items [1] to [6].

[0012] [1] A graft copolymer (X) containing a main chain portion derived from an ethylene·α-olefin copolymer (A), a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, and a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C).

[0013] [2] The graft copolymer (X) according to [1], which contains the above-mentioned main chain portion derived from an unmodified ethylene·α-olefin copolymer (A) satisfying requirements (a-1) to (a-4) and satisfies requirement (x-1). (a-1) The Brookfield viscosity (150 °C) is 1 to 5000 mPa·s. (a-2) It contains 30 to 80 mol% of skeletal units derived from ethylene and 70 to 20 mol% of skeletal units derived from α-olefin (however, the total amount of skeletal units derived from ethylene and skeletal units derived from α-olefin is 100 mol%). (a-3) No melting point is observed by differential scanning calorimetry (DSC). (a-4) The weight average molecular weight (Mw) in terms of polystyrene determined by gel permeation chromatography (GPC) is from 1,000 to 20,000. (x-1) The total of the proportion of the graft portion derived from the organosilicon compound (B) and the proportion of the graft portion derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) is from 0.1 to 20% by mass (where the mass of the graft copolymer (X) is taken as 100% by mass).

[0014] [3] The ethylene·α-olefin copolymer (A) from which the main chain portion is derived contains ethylene-derived skeletal units in the range of 40 to 75 mol% (where the total amount of the ethylene-derived skeletal units and the α-olefin-derived skeletal units of the ethylene·α-olefin copolymer (A) is taken as 100 mol%). The graft copolymer (X) according to [1] or [2].

[0015] [4] The proportion of the graft portion derived from the organosilicon compound (B) is from 1 to 19% by mass, and the proportion of the graft portion derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) is from 1 to 8% by mass (where the mass of the graft copolymer (X) is taken as 100% by mass). The graft copolymer (X) according to any one of [1] to [3].

[0016] [5] The organosilicon compound (B) is vinyltrimethoxysilane, and the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) is maleic anhydride. The graft copolymer (X) according to any one of [1] to [4].

[0017] [6] In terms of polystyrene determined by gel permeation chromatography (GPC), the graft copolymer (X) has a weight average molecular weight (Mw) in the range of 1,800 to 19,000, a number average molecular weight (Mn) in the range of 1,500 to 9,500, and a molecular weight distribution (Mw / Mn) in the range of 1.4 to 2.1. The graft copolymer (X) according to any one of [1] to [5].

Advantages of the Invention

[0018] According to the present invention, a graft copolymer having a main chain portion derived from an ethylene-α-olefin copolymer (A) and a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, which can be emulsified alone, can be obtained.

Mode for Carrying Out the Invention

[0019] ≪Graft Copolymer (X)≫ The graft copolymer (X) according to the present invention includes a main chain portion derived from an ethylene-α-olefin copolymer (A), a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, and a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C). Hereinafter, after describing the main chain portion of the graft copolymer (X) according to the present invention and the graft portions of the graft copolymer (X), the physical properties of the graft copolymer (X) will be explained. In the present specification and the claims, "A to B" indicating a numerical range means A or more and B or less.

[0020] <Main Chain Portion> The main chain portion of the graft copolymer (X) is derived from an ethylene-α-olefin copolymer (A). The unmodified ethylene-α-olefin copolymer (A) serving as the raw material of the main chain portion satisfies the following requirements (a-1) to (a-4). The ethylene-α-olefin copolymer (A) may be used alone or in combination of two or more.

[0021] Requirement (a-1) The Brookfield viscosity (BF viscosity) at 150 ° C is preferably in the range of 1 to 5000 mPa·s, more preferably in the range of 5 to 2500 mPa·s, and still more preferably in the range of 10 to 1000 mPa·s. When the BF viscosity of the ethylene-α-olefin copolymer (A) at 150 ° C is within the above numerical range, for example, when a sizing agent containing the graft copolymer (X) is applied to glass fibers, the glass fibers after application are easy to handle, and the appearance of the glass fibers coated with the graft copolymer (X) is good, which is preferable.

[0022] Requirement (a-2) The unmodified ethylene-α-olefin copolymer (A) preferably contains 30 to 80 mol%, more preferably 40 to 75 mol%, still more preferably 40 to 60 mol% of the skeletal units derived from ethylene, and preferably 20 to 70 mol%, more preferably 25 to 60 mol%, still more preferably 40 to 60 mol% of the skeletal units derived from an α-olefin having 3 to 20 carbon atoms (however, the total amount of the skeletal units derived from ethylene and the skeletal units derived from an α-olefin having 3 to 20 carbon atoms is 100 mol%). When the proportion of the skeletal units derived from ethylene in the unmodified ethylene-α-olefin copolymer (A) (hereinafter also referred to as "ethylene content") is within the above range, the crystallinity of the ethylene-α-olefin copolymer (A) does not become too high, and a decrease in fluidity is less likely to occur, which is preferable. Further, when the proportion of the skeletal units derived from α-olefin in the unmodified ethylene-α-olefin copolymer (A) (hereinafter also referred to as "α-olefin content") is within the above range, the crystallinity of the ethylene-α-olefin copolymer (A) does not become too high, and a decrease in fluidity is less likely to occur, which is preferable.

[0023] Typical examples of the α-olefin having 3 to 20 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 and the like. These α-olefins may be used alone or in combination of two or more. Among these α-olefins, α-olefins having 3 to 10 carbon atoms are preferable, and propylene is particularly preferable, in terms of easy availability.

[0024] The ethylene content of the unmodified ethylene-α-olefin copolymer (A) is 13It can be measured by the 13C-NMR method, and for example, the peak can be identified and quantified according to the methods described in the examples below and the methods described in "Polymer Analysis Handbook" (published by Asakura Shoten, P163 - 170).

[0025] Requirement (a - 3) When the temperature range of - 100°C to 150°C is set as the observation target by differential scanning calorimetry (DSC), no melting point is observed by differential scanning calorimetry. It is preferable that the unmodified ethylene·α - olefin copolymer (A) shows no melting point by differential scanning calorimetry. Here, "no melting point (Tm) is observed" means that the heat of fusion (ΔH) (unit: J / g) is not substantially measured in differential scanning calorimetry. "The heat of fusion (ΔH) is not substantially measured" means that no peak is observed in the DSC curve obtained by measurement with a differential scanning calorimeter, or the observed heat of fusion is 1 J / g or less. The melting point (Tm) and the heat of fusion (ΔH) of the ethylene·α - olefin polymer (A) are determined by a differential scanning calorimeter from the DSC curve when the ethylene·α - olefin polymer (A) is cooled to - 100°C and then heated to 150°C at a heating rate of 10°C / min, and the obtained DSC curve is analyzed and determined in accordance with JIS K7121. When the melting point of the ethylene·α - olefin polymer (A) is not observed by DSC, it is preferable because the content of crystal components such as polyethylene, which are impurities in the ethylene·α - olefin polymer (A), is extremely low.

[0026] Requirement (a - 4) The unmodified ethylene·α - olefin copolymer (A) preferably has a weight - average molecular weight (Mw) (in terms of polystyrene) of 1,000 to 20,000, more preferably 1,000 to 19,000, and even more preferably 1,500 to 18,000, as determined by gel permeation chromatography (GPC) under the conditions adopted in the examples described below. When the Mw of the unmodified ethylene-α-olefin copolymer (A) is within the above range, for example, when a sizing agent containing the graft copolymer (X) is applied to glass fibers, the glass fibers after application are easy to handle, and since the appearance of the glass fibers coated with the graft copolymer (X) is good, it is preferable.

[0027] Also, the molecular weight distribution (Mw / Mn) of the ethylene-α-olefin copolymer (A) obtained by the method described in the examples below is not particularly limited, but is usually 3 or less, preferably 2.7 or less, more preferably 2.5 or less.

[0028] <Method for producing ethylene-α-olefin copolymer (A)> The method for producing the unmodified ethylene-α-olefin copolymer (A) is not particularly limited, and it can be produced using a known method. For example, a method of copolymerizing ethylene and an α-olefin in the presence of a catalyst composed of a compound containing a transition metal such as vanadium, zirconium, titanium, hafnium, etc., and an organoaluminum compound (including an organoaluminum oxy compound) and / or an ionized ionic compound can be mentioned. Examples of such methods include those described in International Publication No. 2000 / 34420, JP-A-62-121710, International Publication No. 2004 / 29062, JP-A-2004-175707, International Publication No. 2001 / 27124, etc. Among these, a method using a catalyst system containing a metallocene compound such as zirconocene and an organoaluminum oxy compound (aluminoxane) can produce a copolymer with high polymerization activity, and at the same time, it can reduce the chlorine content of the resulting copolymer and the 1,1’ or 2,2’-bond amount (inversion) of the α-olefin monomer, so it is preferable.

[0029] <Graft portion derived from organosilicon compound (B)> The graft copolymer (X) has a graft portion derived from the organosilicon compound (B). The organosilicon compound (B) that forms the graft portion of the graft copolymer (X) is an organosilicon compound containing one or more unsaturated groups, and is usually an organosilicon compound containing one or more unsaturated groups having 2 to 20 carbon atoms. Examples of the organosilicon compound (B) include monovinylsilanes such as vinyltrimethoxysilane (VTMOS), vinyltriethoxysilane, vinyltrimethylsilane, diethylmethylvinylsilane, diacetoxyethylvinylsilane, diethoxymethylvinylsilane, ethoxydimethylvinylsilane, triacetoxyvinylsilane, tris(2-methoxyethoxy)vinylsilane, triphenylvinylsilane, triphenoxyvinylsilane, etc., and polyvinylsilanes such as diphenyldivinylsilane, allyloxydimethylvinylsilane, etc.

[0030] <Generation conditions of the graft portion derived from the organosilicon compound (B)> The grafting for generating the graft portion derived from the organosilicon compound (B) can be carried out in the presence of a solvent, and can also be carried out in the absence of a solvent. For example, the polymer to be grafted is heated, and the organosilicon compound (B) and a radical initiator are continuously or intermittently supplied under stirring to carry out grafting. The proportion of the organosilicon compound (B) supplied during grafting is usually in the range of 1 to 150 parts by mass, preferably 1.2 to 120 parts by mass, based on 100 parts by mass of the unmodified ethylene·α-olefin copolymer (A). The proportion of the radical initiator is usually in the range of 0.04 to 5 parts by mass, preferably 0.1 to 1 part by mass, based on 100 parts by mass of the unmodified ethylene·α-olefin copolymer (A). The temperature during the reaction is usually in the range of 120 to 200°C, preferably 130 to 180°C. The time required for the reaction is usually 30 minutes to 10 hours, preferably 1 to 5 hours.

[0031] As a radical initiator used in the graft reaction, organic peroxides are usually used, and organic peroxides having a decomposition temperature with a half-life of 1 hour in the range of 100 to 180 ° C are particularly preferred. Examples of such organic peroxides include organic peroxides such as dicumyl peroxide (Perkyl D), di-tert-butyl peroxide (Perbutyl D), 1,1-di(tert-butylperoxy)cyclohexane (Perhexa C), tert-butyl peroxy-2-ethylhexyl monocarbonate (Perbutyl E), di-tert-hexyl peroxide (Perhexyl Z), t-hexyl peroxybenzoate (Perhexyl Z), 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (Perhexa 25M), tert-butyl peroxybenzoate (Perbutyl Z), tert-butyl peroxyisopropyl monocarbonate (Perbutyl I) (note that the expressions in parentheses are all product names of NOF Corporation).

[0032] <Graft portion derived from unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C)> The graft copolymer (X) further has a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C). The unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) that forms the graft portion of the graft copolymer (X) is usually an α,β-unsaturated carboxylic acid or a derivative thereof.

[0033] Examples of the unsaturated carboxylic acid include (meth)acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid (endo-cis-bicyclo[2,2,1]hept-5-ene-2,3-dicarboxylic acid), and the like. Examples of the derivative of the unsaturated carboxylic acid include acid anhydrides, esters, amides, and imides of the unsaturated carboxylic acid.

[0034] Examples of esters of unsaturated carboxylic acids include esters and half-esters such as methyl (meth)acrylate, ethyl (meth)acrylate, monoethyl maleate, diethyl maleate, monomethyl fumarate, dimethyl fumarate, monomethyl itaconate, and diethyl itaconate.

[0035] Examples of amides of unsaturated carboxylic acids include (meth)acrylamide, maleic acid monoamide, maleic acid diamide, maleic acid - N - monoethylamide, maleic acid - N,N - diethylamide, maleic acid - N - monobutylamide, maleic acid - N,N - dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid - N - monobutylamide, and fumaric acid - N,N - dibutylamide.

[0036] Examples of imides of unsaturated carboxylic acids include maleimide, N - butyl maleimide, and N - phenyl maleimide. Among unsaturated carboxylic acids and their derivatives, unsaturated dicarboxylic acids and their derivatives are more preferred. Particularly, maleic acid and maleic anhydride are particularly preferred in terms of, for example, being less likely to generate by - products such as homopolymers in the reaction for producing the modified copolymer.

[0037] <Generation conditions of the graft portion derived from unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C)> When grafting to generate a graft portion derived from unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C), the polymer to be grafted is heated, and under stirring, the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) and a radical initiator are continuously or intermittently supplied to perform grafting.

[0038] The charged amount of the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) is usually 0.010 to 15 parts by mass, preferably 0.010 to 5.0 parts by mass, based on 100 parts by mass of the ethylene-α-olefin copolymer (A). The amount of the radical initiator used is usually 0.0010 to 1.0 parts by mass, preferably 0.0010 to 0.30 parts by mass, based on 100 parts by mass of the ethylene-α-olefin copolymer (A).

[0039] As the radical initiator, for example, an organic peroxide, an azo compound or a metal hydride can be used. Examples of the organic peroxide include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide and the like. Examples of the azo compound include azobisisobutyronitrile, dimethylazoisobutyrate and the like.

[0040] The radical initiator can be used by mixing it as it is with the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C), and the polymer to be grafted (the unmodified ethylene-α-olefin copolymer (A) or the ethylene-α-olefin copolymer after grafting derived from the organosilicon compound (B)), but it can also be used after dissolving it in a small amount of an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the radical initiator. The graft modification with the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) can be carried out by a conventionally known method.

[0041] For example, a method is exemplified in which the polymer to be grafted is dissolved in an organic solvent, and then the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) and the radical initiator are added to the solution, and the reaction is usually carried out at a temperature of 70 to 200 ° C, preferably 80 to 190 ° C, and usually for 0.5 to 15 hours, preferably 1 to 10 hours.

[0042] Further, a modified product can also be produced by reacting, using an extruder or the like, a polymer to be grafted with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C) in the absence of a solvent and in the presence of a radical initiator. This reaction is usually preferably carried out at a temperature equal to or higher than the melting point of the polymer to be grafted, usually for 0.5 to 10 minutes.

[0043] <Physical properties of the graft copolymer (X)> The graft copolymer (X) preferably satisfies the following requirement (x-1). Requirement (x-1) The total of the proportion of the graft portion derived from the organosilicon compound (B) and the proportion of the graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) is preferably 0.1 to 20% by mass, more preferably 4 to 15% by mass, and still more preferably 8 to 15% by mass (where the mass of the graft copolymer (X) is 100% by mass). Hereinafter, the total of the proportion of the graft portion derived from the organosilicon compound (B) and the proportion of the graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) may be referred to as the "modification amount" of the graft copolymer (X). When the modification amount of the graft copolymer (X) is within the above range, it is preferable because it tends to be easily emulsified alone. It is presumed that the reason for obtaining such an effect is that the balance between hydrophilicity and hydrophobicity is more suitable for emulsification. Note that the graft position is not particularly limited for either the graft portion derived from the organosilicon compound (B) or the graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C).

[0044] The proportion of the graft portion derived from the organosilicon compound (B) in the graft copolymer (X) is preferably 1 to 19% by mass, more preferably 2 to 10% by mass, and still more preferably 3 to 10% by mass (where the mass of the graft copolymer (X) is 100% by mass). When the proportion of the graft portion derived from the organosilicon compound (B) is within the above range, the obtained graft copolymer (X) is preferable because it is excellent in both the affinity with other resins and the affinity with inorganic fibers such as glass fibers. The graft amount derived from the organosilicon compound (B) in the graft copolymer (X) is 1 determinable by 1H-NMR. Specifically, under the conditions described in the examples below, 1 an 1H-NMR spectrum is measured, and it can be calculated by the method described in the examples using the peak area of the group derived from the grafted organosilicon compound (B).

[0045] The proportion of the graft portion derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) in the graft copolymer (X) is preferably 1 to 8% by mass, more preferably 3 to 5% by mass, and even more preferably 4 to 5% by mass (however, the mass of the graft copolymer (X) is taken as 100% by mass). When the proportion of the graft portion derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) is within the above range, it is preferable because the graft copolymer (X) can be easily emulsified. The graft amount derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) in the graft copolymer (X) is 1 determinable by 1H-NMR. Specifically, under the conditions described in the examples below, 1 an 1H-NMR spectrum is measured, and it can be calculated by the method described in the examples using the peak area of the group derived from the grafted unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C).

[0046] The weight-average molecular weight (Mw) in terms of polystyrene determined by gel permeation chromatography (GPC) of the graft copolymer (X) under the conditions employed in the examples described below is preferably in the range of 1,800 to 19,000, more preferably in the range of 2,000 to 18,000, and even more preferably in the range of 2,500 to 17,000. When the weight-average molecular weight (Mw) of the graft copolymer (X) is within the above range, for example, even when the graft copolymer (X) is mixed with another resin and this mixture is emulsified, it is preferable because the emulsifying property is maintained well and the affinity with the other resin is good. The number average molecular weight (Mn) in terms of polystyrene of the graft copolymer (X), as determined by GPC under the conditions adopted in the examples described later, is preferably in the range of 1,500 to 9,500, more preferably in the range of 1,600 to 9,000, and even more preferably in the range of 1,650 to 8,500. When the number average molecular weight (Mn) of the graft copolymer (X) is within the above range, for example, even when the graft copolymer (X) and another resin are mixed and this mixture is emulsified, it is preferable because the emulsifying property is kept good and the affinity with another resin is good. The molecular weight distribution (Mw / Mn) of the graft copolymer (X) is preferably in the range of 1.4 to 2.1, more preferably in the range of 1.5 to 2.0, and even more preferably in the range of 1.5 to 1.9. When the molecular weight distribution (Mw / Mn) of the graft copolymer (X) is within the above range, for example, even when the graft copolymer (X) and another resin are mixed and this mixture is emulsified, it is preferable because the emulsifying property is kept good and the affinity with another resin is good.

[0047] <Production method of graft copolymer (X)> The graft copolymer (X) may be obtained by reacting an unmodified ethylene·α-olefin copolymer (A) with an organosilicon compound (B) containing one or more unsaturated groups and an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C) to form a graft copolymer having a main chain portion derived from the ethylene·α-olefin copolymer (A), a graft portion derived from the organosilicon compound (B), and a graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C). By such a reaction, a graft copolymer (X) containing a main chain portion derived from the ethylene·α-olefin copolymer (A), a graft portion derived from the organosilicon compound (B) containing one or more unsaturated groups, and a graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) is obtained. For example, the graft copolymer (X) can be produced by any of the following methods (M-1) to (M-3).

[0048] Method (M-1) The unmodified ethylene-α-olefin copolymer (A) is reacted with the organosilicon compound (B) in the presence of a radical initiator for grafting, and then the grafted copolymer is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C) in the presence of a radical initiator to produce the graft copolymer (X).

[0049] Method (M-2) The unmodified ethylene-α-olefin copolymer (A) is reacted with an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C) in the presence of a radical initiator for grafting, and then the grafted copolymer is reacted with the organosilicon compound (B) in the presence of a radical initiator to produce the graft copolymer (X).

[0050] Method (M-3) The unmodified ethylene-α-olefin copolymer (A), the organosilicon compound (B), and the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) are reacted in the presence of a radical initiator to produce the graft copolymer (X).

[0051] From the viewpoint of suppressing the formation of a copolymer of the organosilicon compound (B) and the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) as a by-product, the method for producing the graft copolymer (X) is preferably any one of methods (M-1) and (M-2). The method for producing the graft copolymer (X) is more preferably method (M-1) because it is difficult for a high molecular weight substance to be generated as a by-product. When a high molecular weight substance is generated as a by-product, the emulsifying property of the graft copolymer (X) tends to deteriorate due to the presence of the high molecular weight substance. In addition, a gel fraction is likely to be generated from the high molecular weight substance. For example, when a sizing agent containing the graft copolymer (X) is prepared and the fiber is treated with the sizing agent, poor appearance of the fiber is likely to occur. The presence of the high molecular weight substance can be specified by, for example, GPC.

[0052] ≪Emulsification method of graft copolymer (X)≫ The graft copolymer (X) can be made into an aqueous dispersion by emulsifying it alone in water. The method of dispersing the graft copolymer (X) in water is, for example, as disclosed in Japanese Patent Publication No. Sho 7-008933, Japanese Patent Publication No. Sho 7-096647, Japanese Patent Publication No. Sho 5-039975, etc., to neutralize or saponify the group derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) in the graft copolymer (X) in water.

[0053] In the production of the aqueous dispersion, examples of the basic substance used for neutralization and saponification include alkali metals such as sodium, potassium, lithium, calcium, magnesium, zinc and / or alkaline earth metals and / or other metals, inorganic amines such as hydroxylamine and ammonium hydroxide, ammonia, organic amines such as (tri)methylamine, (tri)ethanolamine, (tri)ethylamine, dimethylethanolamine and morpholine, sodium oxide, sodium peroxide, oxides of alkali metals and / or alkaline earth metals and / or other metals, hydroxides, hydrides, and weak acid salts of alkali metals and / or alkaline earth metals and / or other metals such as sodium carbonate.

[0054] As the carboxylic acid group or carboxylic acid ester group neutralized or saponified by the basic substance, alkali metal carboxylates such as sodium carboxylate and potassium carboxylate or ammonium carboxylate are preferred.

[0055] Also, from the viewpoints of the stability of the aqueous dispersion and the adhesion to the fiber, the degree of neutralization or saponification is usually 50 to 100%, preferably 70 to 100%, more preferably 85 to 100%.

[0056] In the aqueous dispersion of the graft copolymer (X) obtained by the above method, if necessary, organic pigments such as azo pigments and phthalocyanine blue; dyes such as azo dyes and anthraquinone dyes; binders such as inorganic chemicals such as aluminum oxide, calcium carbonate, calcium hydroxide, magnesium hydroxide, silica and barium titanate; coloring agents such as inorganic pigments such as titanium oxide, molybdenum and carbon black, etc. can be contained.

[0057] In the aqueous dispersion of the graft copolymer (X) obtained by the above method, various stabilizers such as antioxidants, weather stabilizers and heat stabilizers; defoamers, thickeners, dispersants, surfactants, fungicides, antibacterial agents, preservatives, catalysts, fillers, waxes, antiblocking agents, plasticizers, leveling agents and other components can be further contained. In particular, when the aqueous dispersion of the graft copolymer (X) is used in a process involving heating, or when heat is applied during the molding of the material treated with the aqueous dispersion, it is preferable to use an antioxidant or a heat stabilizer, etc. In particular, from the viewpoints of processing and long-term stability, it is preferable to use a phenolic antioxidant and a phosphorus-based processing stabilizer in combination. The addition amount (total amount of various stabilizers) of various stabilizers is preferably 5% by mass or less, more preferably 2% by mass or less, based on the graft copolymer (X).

[0058] ≪Uses of the graft copolymer (X)≫ The aqueous dispersion of the graft copolymer (X) can be used as a sizing agent and can be blended into fiber-reinforced resins. Furthermore, the graft copolymer (X) can also be used as a coating agent, an organic filler dispersant, an inorganic filler dispersant, a battery binder, an adhesion-imparting agent, etc. When the graft copolymer (X) is used as a coating agent, the uses of the coating agent include paints, ink additives, metal paints, paper coating agents, heat sealants, various primers, etc. When the graft copolymer (X) is used as a coating agent, the coating agent may be either an aqueous coating agent or a solvent-based coating agent.

[0059] The fibers to be treated with the sizing agent composed of the aqueous dispersion of the graft copolymer (X) are not particularly limited, but can be widely used for inorganic fibers conventionally known as resin reinforcing materials, such as glass fibers, carbon fibers, alumina fibers, ceramic fibers, rock fibers, slag fibers, and metal fibers. Among the above inorganic fibers, carbon fibers and glass fibers are preferred.

[0060] The average fiber diameter of the fibers treated with the aqueous dispersion of the graft copolymer (X) is not particularly limited, but from the viewpoints of the mechanical properties and surface appearance of the resulting molded article, it is preferably in the range of 1 to 20 μm, more preferably 3 to 15 μm. There is no particular limitation on the number of single filaments in the fiber bundle to be treated, which is usually 100 to 350,000, preferably in the range of 1,000 to 250,000. When the object to be treated is a reinforcing fiber, from the viewpoint of the productivity of the reinforcing fiber, those with a larger number of single filaments are preferred, and it is preferably in the range of 20,000 to 100,000. Further, the thickness of the strand obtained by the treatment is usually 10 to 10,000 tex, preferably in the range of 100 to 5,000 tex.

[0061] The aqueous dispersion of the graft copolymer (X) can be widely used as a sizing agent for fibers such as polyolefin fibers, nylon fibers, vinylon fibers, acrylic fibers, polyester fibers, polyurethane fibers, and glass fibers. Among the above fibers, polyolefin fibers and glass fibers are preferred, and specifically, ethylene-based fibers, propylene-based fibers, glass fibers, etc. are preferred.

[0062] As a method for treating fibers with the aqueous dispersion of the graft copolymer (X), there are methods such as an immersion method, a spray method, a roller coating method, etc., in which the aqueous dispersion is adhered to the fibers and then dried at 50 to 300 °C for about 1 minute to 10 hours, but it is not particularly limited. Also, the adhesion amount of the graft copolymer (X) is usually 0.1 to 40% by mass, preferably 0.3 to 37% by mass, more preferably 0.5 to 35% by mass with respect to the fibers in terms of easy dispersion of the fibers.

[0063] The single fibers that form the fiber bundle to be treated with the aqueous dispersion of the graft copolymer (X) preferably have more than 60% of the single fiber surface coated with resin in order to exhibit stronger adhesiveness. The uncoated part cannot exhibit adhesiveness and becomes the starting point of peeling, resulting in a decrease in adhesiveness. Preferably, the state is such that 70% or more is coated, and more preferably 80% or more is coated. The coating state can be determined by methods such as using a scanning electron microscope (SEM) or a method of tracing the metal element of the carboxylate by elemental analysis of the fiber surface.

Examples

[0064] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[0065] [Measurement methods of physical properties] The measurement methods of various physical properties of the unmodified ethylene-α-olefin copolymer (A) and the graft copolymer (X) are as follows.

[0066] <Brookfield (BF) viscosity at 150 °C> The Brookfield viscosity of the unmodified ethylene-α-olefin copolymer (A) at 150 °C was measured by the method described in JIS K7117-1.

[0067] <Ethylene content (mol%)> The ethylene content of the unmodified ethylene-α-olefin copolymer (A) was measured under the following conditions using a JEOL ECP500 nuclear magnetic resonance apparatus. 13 C-NMR measurement was performed. Solvent: Orthodichlorobenzene / deuterated benzene (80 / 20 vol%) mixed solvent Sample concentration: 55 mg / 0.6 mL Measurement temperature: 120 °C Observed nucleus: 13 C (125 MHz) Sequence: Single pulse proton decoupling Pulse width: 4.7 μ / s (45° pulse), Repeating time: 5.5 seconds Number of integrations: 10,000 times or more Reference value of chemical shift: 27.50 ppm

[0068] The ethylene content of the unmodified ethylene-α-olefin copolymer (A) was obtained from the 13 C-NMR spectrum based on the reports of "Polymer Analysis Handbook" (published by Asakura Shoten, pp. 163 - 170), G. J. Ray (Macromolecules, 10, 773 (1977)), J. C. Randall (Macromolecules, 15, 353 (1982)), K. Kimura (Polymer, 25, 4418 (1984)), etc.

[0069] <Melting point> The measurement of the melting peak of the unmodified ethylene-α-olefin copolymer (A) was carried out using X-DSC-7000 manufactured by Seiko Instruments Inc. Approximately 8 mg of the sample was placed in an aluminum sample pan that can be simply sealed and placed in the DSC cell. The DSC cell was heated from room temperature to 150 °C at a rate of 10 °C / min under a nitrogen atmosphere, then held at 150 °C for 5 minutes, and then cooled at a rate of 10 °C / min until the DSC cell was cooled to -100 °C (cooling process). After holding at -100 °C for 5 minutes, it was heated from -100 °C to 15 °C at a rate of 10 °C / min. The temperature at which the DSC curve obtained during the heating process shows a maximum value was defined as the melting point (Tm), and the total heat absorption amount accompanying melting was defined as the heat of fusion (ΔH). When no peak was observed or the value of the heat of fusion (ΔH) was 1 J / g or less, the melting peak was considered not to be observed. The melting point (Tm) and the heat of fusion (ΔH) were determined based on JIS K7121.

[0070] <Weight-average molecular weight (Mw), number-average molecular weight (Mn), molecular weight distribution (Mw / Mn)> For each of the unmodified ethylene-α-olefin copolymer (A) and the graft copolymer (X), gel permeation chromatography measurement was carried out under the following conditions using the following high-speed GPC measuring device to obtain the weight-average molecular weight Mw, number-average molecular weight Mn, and molecular weight distribution (Mw / Mn). High-speed GPC measurement device: HLC8320GPC manufactured by Tosoh Corporation Mobile phase: THF (manufactured by Wako Pure Chemical Industries, Ltd., stabilizer-free, grade for liquid chromatography) Column: Two TSKgel Super Multipore HZ-M columns manufactured by Tosoh Corporation connected in series Sample concentration: 5 mg / mL Mobile phase flow rate: 0.35 mL / min Measurement temperature: 40 °C Standard sample for calibration curve: PStQuick MP-M (standard polystyrene kit) manufactured by Tosoh Corporation

[0071] <Amount of modification of graft copolymer (X)> To determine the amount of modification of graft copolymer (X), the ratio of the graft portion derived from organosilicon compound (B) and the ratio of the graft portion derived from unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C) were determined.

[0072] To determine the ratio of the graft portion derived from organosilicon compound (B), the following conditions were used 1 1H-NMR measurement was performed. Measurement device: AVANCE III cryo-270 type nuclear magnetic resonance apparatus (270 MHz) manufactured by Bruker BioSpin Corporation Measurement solvent: deuterated chloroform Sample concentration: 20 mg / 0.6 mL Measurement temperature: 24.3 °C Spectral width: 15.6 ppm Sequence: NON Pulse width: 6.5 μsec Repetition time: 2.5 seconds Number of accumulations: 16 times Reference value of chemical shift: 7.26 ppm In the following examples, since vinyltrimethoxysilane is used as organosilicon compound (B), the ratio of the graft portion derived from organosilicon compound (B) was calculated from the area ratio between the peak corresponding to the structure (main chain portion) derived from ethylene·α-olefin in the spectrum obtained by the above measurement and the peak of the methoxy group derived from vinyltrimethoxysilane.

[0073] In order to determine the proportion of the graft portion derived from the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C), under the same conditions as when determining the proportion of the graft portion derived from the organosilicon compound (B), 1 1H-NMR measurement was carried out. In the following examples, since maleic anhydride is used as the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C), from the area ratio between the peak corresponding to the structure (main chain portion) derived from ethylene·α-olefin in the spectrum obtained by the above measurement and the peak corresponding to the structure derived from maleic anhydride, the proportion of the graft portion derived from maleic anhydride was calculated.

[0074] [Examples] In the examples, vinyltrimethoxysilane was used as the organosilicon compound (B), and according to the above method (M-2), using a copolymer modified with maleic anhydride, a graft copolymer (X-1) was synthesized by the following method. That is, this example corresponds to an example using maleic anhydride as the unsaturated carboxylic acid or unsaturated carboxylic acid derivative (C). The physical properties of the unmodified ethylene·propylene copolymer (A-1) from which the main chain portion of the maleic anhydride-modified ethylene·propylene copolymer is derived are as follows. Each physical property was measured by the above measurement method. Brookfield viscosity (150 °C): 70 mPa·s Ethylene-derived skeletal unit: 48.5 mol% Propylene-derived skeletal unit: 51.5 mol% Melting point (differential scanning calorimetry): Not observed Weight average molecular weight (Mw): 4,800

[0075] 177 g of maleic anhydride-modified ethylene-propylene copolymer (maleic anhydride modification rate 5% by mass, Mw 5,620, Mn 3,000) and 25.5 g of vinyltrimethoxysilane were placed in a 1-liter glass reaction vessel. After purging the system with nitrogen, it was sealed. While stirring at 200 rpm using a double anchor blade, the temperature inside the system was raised to 160 °C. 50 mL of a solution prepared by dissolving 1.02 g of dicumyl peroxide (manufactured by NOF Corporation, product name: PERKOMYL D) in toluene was added dropwise to the reaction vessel over 60 minutes while stirring at 400 rpm. After completion of the dropwise addition, stirring was continued for another 90 minutes. Then, the stirring speed was reduced to 300 rpm and the mixture was cooled to 50 °C. The reaction vessel was depressurized and opened, and the reaction solution was taken out. Toluene as the solvent and vinyltrimethoxysilane were distilled off under reduced pressure using an evaporator. Then, it was vacuum dried at 90 °C to obtain a graft copolymer (X-1).

[0076] The physical properties of the graft copolymer (X-1) were as follows. Each physical property was measured by the above measurement method. Graft amount of vinyltrimethoxysilane: 4.3% by mass Graft amount of maleic anhydride: 4.9% by mass Weight average molecular weight (Mw): 4,620 Number average molecular weight (Mn): 2,750 Molecular weight distribution (Mw / Mn): 1.9

[0077] [Raw materials] The raw materials used in the following Preparation Examples and Comparative Preparation Examples are as follows. · "Graft copolymer (X-1)": The graft copolymer (X-1) synthesized in the above Example was used. · "Silane-modified product": Silane-modified ethylene-propylene copolymer (Mw: about 5,000) · "Maleic anhydride-modified product 1": Maleic anhydride-modified ethylene-propylene copolymer (Mw: about 5,000) · "Maleic anhydride-modified product 2": Maleic anhydride-modified polyolefin (Mw: about 200,000)

[0078] [Preparation Example 1] 18 g of graft copolymer (X-1), 42 g of maleic anhydride-modified product 1, and 15 g of nonionic surfactant Emulgen 1108 (manufactured by Kao Corporation) were put into a 500 mL container (weight ratio of graft copolymer (X-1) / maleic anhydride-modified product 1 / Emulgen 1108 = 24 / 56 / 20), and the temperature was raised to 90 °C while stirring at 100 rpm. After adding 10 g of water and 5.6 g of morpholine, it was stirred at 95 °C and 150 rpm for 30 minutes (neutralization reaction). 159.4 g of boiling hot water was added, and it was stirred at 95 °C and 250 rpm for 60 minutes (emulsification). Then, it was allowed to cool while stirring at 100 rpm to obtain an aqueous dispersion.

[0079] For the aqueous dispersion obtained in Preparation Example 1, the emulsifying property evaluation, measurement of the average particle size (D50 value) of the emulsion, and evaluation of the emulsion stability were carried out by the following methods.

[0080] 〔Emulsifying property evaluation〕 The emulsifying property of the obtained aqueous dispersion was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1. (Evaluation criteria) ○: The graft copolymer is dispersed in water. ×: The graft copolymer and water are immiscible (separate).

[0081] 〔Measurement of average particle size〕 The average particle size (D50 value) of the emulsion contained in the obtained aqueous dispersion was measured by the dynamic light scattering method. For the measurement, a nanoparticle size measuring device manufactured by Microtrac Bell Corporation was used. The measurement results are shown in Table 1.

[0082] 〔Emulsion stability evaluation〕 The emulsion stability of the obtained aqueous dispersion was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1. In addition, when the evaluation criteria for emulsion stability correspond to ×, cases where it is impossible to evaluate due to the inability to prepare an aqueous dispersion (indicated as "-" in Table 1) are included. (Evaluation criteria) ○: The average particle size is less than 250 nm, and the dispersed state persists for 24 hours or more. △: The average particle size is 250 nm or more and less than 1000 nm, and the duration for which the dispersed state persists is 10 minutes or more, or the average particle size is less than 250 nm, and the duration for which the dispersed state persists is 10 minutes or more and less than 24 hours. ×: The average particle size is 1000 nm or more, or the duration for which the dispersed state persists is less than 10 minutes.

[0083] [Processing Example 1] The aqueous dispersion obtained in Preparation Example 1 was added at 1% by mass based on the solid content of glass fibers having a diameter of 14 μm, and the glass fibers were aggregated to obtain a strand of 2,400 tex. The amount of the graft copolymer (X) adhered was 1% by mass when the mass of the glass fibers was 100% by mass.

[0084] [Evaluation of GF Aggregation Property] Using the strand obtained in Processing Example 1, the aggregation property of the glass fiber (GF) was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1. In Table 1, when the strand itself could not be manufactured because an aqueous dispersion could not be prepared, it is indicated as "-" (evaluation impossible). (Evaluation Criteria) ○: The treated glass fiber bundle does not loosen at all, and roving is easy (easy to handle). △: The treated glass fiber bundle hardly loosens, and roving is possible (handlable). ×: The glass fiber bundle is likely to loosen, and roving is difficult (difficult to handle).

[0085] [Evaluation of Flexibility (Fiber Opening Property)] Using the strand obtained in Processing Example 1, the flexibility (fiber opening property) of the glass fiber was evaluated according to the following evaluation criteria. The evaluation results are shown in Table 1. In Table 1, when the strand itself could not be manufactured because an aqueous dispersion could not be prepared, it is indicated as "-" (evaluation impossible). (Evaluation Criteria) ○: In the fiber opening step (the step before melt-kneading the resin and the glass fiber) in the glass fiber reinforced resin manufacturing process, the glass fiber bundle is flexible enough to be easily opened by a fiber opener. △: It is slightly difficult to open with a fiber opener. ×: It is difficult to fibrillate with a fibrillating machine.

[0086] [Preparation Example 2, Comparative Preparation Examples 1 to 3] A water dispersion was prepared in the same manner as in Preparation Example 1, except that the formulation of the raw materials used in the preparation of the water dispersion was changed as described in Table 1. The emulsifying property and emulsion stability were evaluated in the same manner as in Preparation Example 1, and the average particle size of the emulsion was measured in the same manner as in Preparation Example 1. Further, using the obtained water dispersion, glass fibers were treated in the same manner as in Treatment Example 1, and the glass fiber bundling property and flexibility were evaluated using the obtained strands. The results are shown in Table 1.

[0087] [Reference Example] As a reference example, the glass fiber bundling property and flexibility of glass fibers not treated with a sizing agent were evaluated according to the above evaluation criteria. The evaluation results in the reference example are shown in Table 1.

[0088]

Table 1

[0089] In the aqueous dispersions of Preparation Examples 1 and 2 using the graft copolymer (X) of the present invention, stable emulsions were obtained. Further, the strands produced using the aqueous dispersions of Preparation Examples 1 and 2 had no problem in roving, and could be easily opened in the opening step before melt-kneading the resin and glass fiber in the production process of the glass fiber reinforced resin. That is, the strands obtained when using the aqueous dispersions of Preparation Examples 1 and 2 have the same ease of handling as the strands obtained using an aqueous dispersion prepared from a graft copolymer having only a functional group derived from an organosilicon compound as a graft portion and a maleic anhydride-modified product, as in Comparative Preparation Example 1. Therefore, when using the graft copolymer (X) of the present invention, the efficiency of the preparation treatment of the aqueous dispersion can be improved without lowering the working efficiency in the roving step and the opening step. In other words, when treating glass fiber using the graft copolymer (X) of the present invention, all of the preparation step of the aqueous dispersion, the roving step of the strand, and the opening step in the production of the glass fiber reinforced resin become efficient.

Claims

1. A main chain portion derived from an unmodified ethylene-α-olefin copolymer (A) satisfying requirements (a-1) to (a-4), a graft portion derived from an organosilicon compound (B) containing one or more unsaturated groups, and a graft portion derived from an unsaturated carboxylic acid or an unsaturated carboxylic acid derivative (C), wherein the proportion of the graft portion derived from the organosilicon compound (B) is 1 to 19% by mass, and the proportion of the graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) is 1 to 8% by mass (assuming the mass of the graft copolymer (X) is 100% by mass). The total of the proportion of the graft portion derived from the organosilicon compound (B) and the proportion of the graft portion derived from the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) is 20% by mass or less (assuming the mass of the graft copolymer (X) is 100% by mass), the graft copolymer (X). (a-1) The Brookfield viscosity (150 °C) is 1 to 5000 mPa·s. (a-2) It contains 30 to 80 mol% of ethylene-derived skeletal units and 70 to 20 mol% of α-olefin-derived skeletal units (where the total amount of ethylene-derived skeletal units and α-olefin-derived skeletal units is 100 mol%). (a-3) No melting point is observed by differential scanning calorimetry (DSC). (a-4) The weight average molecular weight (Mw) in terms of polystyrene determined by gel permeation chromatography (GPC) is 1,000 to 20,000.

2. The ethylene-α-olefin copolymer (A) from which the main chain portion is derived contains ethylene-derived skeletal units in the range of 40 to 75 mol% (where the total amount of ethylene-derived skeletal units and α-olefin-derived skeletal units in the ethylene-α-olefin copolymer (A) is 100 mol%). The graft copolymer (X) according to Claim 1.

3. The organosilicon compound (B) is vinyltrimethoxysilane, and the unsaturated carboxylic acid or the unsaturated carboxylic acid derivative (C) is maleic anhydride. The graft copolymer (X) according to Claim 1 or 2.

4. The graft copolymer (X) has a weight average molecular weight (Mw) in the range of 1,800 to 19,000, a number average molecular weight (Mn) in the range of 1,500 to 9,500, and a molecular weight distribution (Mw / Mn) in the range of 1.4 to 2.1 in terms of polystyrene as determined by gel permeation chromatography (GPC). The graft copolymer (X) according to any one of claims 1 to 3.

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