JP2012201725A - Method for producing acid-modified ethylene-based polymer, and aqueous dispersion of acid-modified ethylene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous dispersion of an acid-modified ethylene-based polymer having fine and good dispersion stability along with high adhesive strength, through conducting an acid-modifying reaction for the high acid modification rate of the corresponding ethylene-based polymer while suppressing its gelatinization by bringing its decline in the rate of MFR (melt flow rate) variation to 30% or less.SOLUTION: A method for producing the acid-modified ethylene-based polymer is provided, comprising: compounding 100 pts.mass of the ethylene-based polymer (A) described below, 1-40 pts.mass of at least the monomer (B) described below and 0.01-2 pts.mass of a mercaptan (C) followed by grafting the polymer using 0.05-0.5 pt.mass of an organic peroxide (D). The polymer (A) is an ethylene-based polymer having at least ethylene-derived structural units; and the monomer (B) is a monomer having at least one unsaturated group and at least one functional group selected from carboxy, acid anhydride and carboxylic ester groups.

Description

  The present invention relates to a method for producing an acid-modified ethylene polymer of polyolefin (hereinafter abbreviated as ethylene polymer) having polyethylene or ethylene as one of the main components, and an aqueous dispersion of the acid-modified ethylene polymer.

  Homopolymers of olefins such as polyethylene, polypropylene and polybutene and copolymers with other copolymerizable monomers based on these olefins (hereinafter collectively referred to as “polyolefins”) Since it is relatively inexpensive and has good moldability, heat resistance, water resistance, solvent resistance, mechanical properties, appearance, etc., it is used in various fields. However, since the polyolefin resin is composed of saturated hydrocarbons, it is poor in chemical reactivity as it is and also has a low polarity, so that adhesiveness, paintability, printability and the like are insufficient.

  Among them, polyethylene is generally called polyethylene and is widely used for packaging films, shopping bags, containers, etc., but among polyolefins, it is a material that is particularly difficult to adhere, paint, print, and the like.

  For this reason, a modified polyolefin having a halogen or a polar group is used for adhesion, coating, printing, etc. to the polyolefin. Among the polyolefins, with respect to polyethylene, sufficient performance is not obtained with modified polyolefins obtained from polypropylene or polybutene.

  In addition, modified polyolefins used for adhesion to polyolefin, painting, printing and the like have been mostly used as aromatic organic solvent varnishes. However, in recent years, there are environmental problems due to organic halogens and aromatics, and the use of an aqueous dispersion of a modified polyolefin resin instead of a modified polyolefin varnish has been studied.

  However, in grafting using a radical hydrogen abstraction reaction often used in an acid modification reaction of polyolefin, a part of the ethylene-based polymer easily causes crosslinking. For this reason, when the acid modification amount is increased, the rate of change in melt flow rate (hereinafter abbreviated as MFR) is reduced to 30% or less due to crosslinking, and a gel due to crosslinking is generated.

  Due to the above problems, the acid-modified ethylene polymer aqueous dispersion uses an acid-modified ethylene polymer having a small value of acid modification rate and MFR change rate. Therefore, it was necessary to use a large amount of emulsifier and dispersant to obtain a dispersion (for example, see Patent Documents 1 to 3). However, since it is difficult to carry out emulsification and dispersion, problems such as coarse particles and bleeding out of the emulsifier from the coating film have been problems.

  As a means for solving the problems of these aqueous dispersions, it is conceivable to obtain a modified product having a high acid modification rate by performing acid modification while suppressing a decrease in MFR change rate. As a method for suppressing the decrease in the MFR change rate, for example, a method of making the cross-linking reaction of polyethylene difficult by causing an acid-denaturing reaction in a dilute solution (for example, see Patent Document 4), a decomposition temperature at which the half-life is 1 minute A method is known in which a specific organic peroxide such as an organic peroxide having a temperature of 50 to 115 ° C. is used to suppress a decrease in MFR change rate and increase a graft amount (for example, Patent Document 5). reference). However, only an acid-modified product having a small graft amount and difficult to emulsify is obtained.

JP 2005-320400 A JP 2008-063557 A JP 2008-169380 A JP 50-004189 A JP 2004-307537 A

  In view of the above situation, the present invention is fine and good by performing an acid modification reaction with a high acid modification rate of an ethylene-based polymer while suppressing gelation by reducing the MFR change rate to 30% or less. An object of the present invention is to provide an acid-modified ethylene polymer aqueous dispersion having excellent dispersion stability and excellent adhesive strength.

  The present inventor manufactured an acid-modified ethylene polymer grafted with an unsaturated carboxylic acid and a mercaptan with respect to the ethylene polymer, and further emulsified and dispersed to obtain an acid-modified ethylene polymer aqueous dispersion. It has been found that the above-mentioned problems can be solved by doing so.

  Specifically, the present invention can be solved as follows.

That is, the present invention
(1) With respect to 100 parts by mass of the following ethylene polymer (A), at least 1 to 40 parts by mass of the following monomer (B) and 0.01 to 2 parts by mass of mercaptans (C) are blended, A process for producing an acid-modified ethylene polymer grafted with 0.05 to 0.5 parts by mass of oxide (D);
(A) an ethylene-based polymer having a structural unit derived from at least ethylene,
(B) a monomer having at least one unsaturated group and at least one functional group selected from a carboxyl group, an acid anhydride group, and a carboxylic acid ester group;
(2) The method for producing an acid-modified ethylene polymer according to (1), wherein the ethylene polymer (A) contains at least 40% by mass of a structural unit derived from ethylene,
(3) The method for producing an acid-modified ethylene polymer according to the above (1) or (2), wherein the mercaptan (C) is an alkyl mercaptan and / or an alkyl mercapto alkylate,
(4) 1 to 10 parts by mass of a monomer (b1) in which the monomer (B) has at least one unsaturated group and at least one functional group selected from a carboxyl group and an acid anhydride group; an unsaturated group; (Meth) acrylic acid alkyl ester (excluding the monomer corresponding to the monomer (b1)) (b2) 0 to 30 parts by mass, which is a monomer having a carboxylic acid ester group (3) The method for producing an acid-modified ethylene polymer according to any one of (1),
(5) An acid-modified ethylene polymer obtained by the method for producing an acid-modified ethylene polymer according to any one of (1) to (4), an acid-modified ethylene polymer, a basic compound, and an aqueous medium. Ethylene-based polymer aqueous dispersion,
It is.

  According to the present invention, it is possible to obtain an acid-modified ethylene polymer having a high acid modification rate compared to the prior art by suppressing gelation by reducing the MFR change rate of the ethylene polymer to 30% or less. By using the obtained acid-modified ethylene polymer, an acid-modified ethylene polymer aqueous dispersion having fine and good dispersion stability and excellent adhesion strength to nonpolar substrates such as polyethylene can be obtained. Can be provided.

  The configuration of the present invention will be described in more detail as follows.

  The ethylene polymer (A) that can be used in the present invention is a copolymer composed of polyethylene and at least one selected from ethylene, α-olefin, and cyclic olefin.

  As α-olefin and cyclic olefin, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-dodecadecene, 4-methyl Examples include -1-pentene, cyclopentene, cyclohexene, cycloheptene, norbornene. Examples of the copolymer include a random copolymer, a block copolymer, a graft copolymer, and a mixture thereof. In particular, ethylene-propylene and ethylene-1-butene copolymers are preferable because they have good compatibility and adhesion with a resin mainly composed of polyolefin and a substrate, and the resin itself is flexible.

The ethylene polymer (A) used in the present invention preferably contains 40% by mass to 100% by mass of ethylene. Compared with the case where ethylene is less than 40% by mass, the case where ethylene is 40% by mass or more is preferable because adhesiveness to a substrate such as polyethylene is sufficiently exhibited. 0 mass% or more and 60 mass% or less consist of the said alpha olefin and a cyclic olefin, and it is preferable to consist of a propylene and 1-butene.

  The molecular weight of the ethylene polymer (A) is preferably a weight average molecular weight of 10,000 or more and 200,000 or less. Compared with the case where the weight average molecular weight is smaller than 10,000, the case where the weight average molecular weight is 10,000 or more and 200,000 or less is preferable because the cohesive force is increased and the effect is improved when adhesion, surface modification, and the like are performed. Compared with the case where the weight average molecular weight is larger than 200,000, when the weight average molecular weight is 10,000 or more and 200,000 or less, the fluidity is improved, so that the monomer (B) is easily dispersed uniformly, the reaction efficiency is improved, and the unreacted This is preferable because the residue of products and the generation of by-products can be suppressed. Further, even when the weight average molecular weight is larger than 200,000, a preferred ethylene polymer (by adjusting the molecular weight to 10,000 to 200,000 by a known method such as adjusting the molecular weight to an appropriate range by thermal degradation or the like) A) can be used.

  The monomer (B) is a monomer having at least one unsaturated group and at least one functional group selected from a carboxyl group, a carboxylic ester group, and an acid anhydride group. The monomer (b1) and (meth) It is preferable to consist of acrylic acid alkyl ester (b2).

  Monomer (b1) is preferably an unsaturated monobasic acid such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, citraconic acid, vinyl acetate , Vinyl esters such as vinyl propionate, unsaturated dibasic acids such as citraconic anhydride, unsaturated dibasic acid anhydrides and unsaturated dibasic acid half esters and unsaturated dibasic acid half amides, aconitic acid, 3 Unsaturated monobasic acids such as butene-1,2,3-tricarboxylic acid, 4-pentene-1,2,4-tricarboxylic acid, mono- and diesters of unsaturated tribasic acid anhydrides and unsaturated tribasic acids, Unsaturated tribasic acid mono, diamide, 1-pentene-1,1,4,4-tetracarboxylic acid, 4-pentene-1,2,3,4-tetracarboxylic acid, 3-hexene Unsaturated tetrabasic acids such as 1,1,6,6-tetracarboxylic acid, unsaturated tetrabasic acid anhydride and unsaturated tetrabasic acid mono, di, triester and unsaturated tetrabasic acid mono, di, triamide And at least one compound selected from the group consisting of As the monomer (b1), an unsaturated carboxylic acid anhydride is preferable, maleic anhydride is particularly preferable because of poor homopolymerization and easy progress of grafting reaction.

  The (meth) acrylic acid alkyl ester (b2) is an acrylic acid alkyl ester or a methacrylic acid alkyl ester, preferably an acrylic acid which is an ester with a linear, branched or cyclic alkyl group having 1 to 18 carbon atoms. Alkyl esters and alkyl methacrylates, specifically, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, i-propyl acrylate, methacryl I-propyl acid, n-butyl acrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate, 2-butyl acrylate, 2-butyl methacrylate, t-butyl acrylate, t-methacrylic acid -Butyl, cyclohexyl acrylate, methacryl Cyclohexyl, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, n-dodecyl acrylate, n-dodecyl methacrylate, n-octadecyl acrylate, n-octadecyl methacrylate, etc. And at least one compound selected from the group consisting of N-Butyl acrylate, 2-ethylhexyl acrylate, n-dodecyl methacrylate, n-octadecyl methacrylate where the glass transition point (Tg) of the homopolymer of (meth) acrylic acid alkyl ester (b2) is −40 ° C. or lower. Is preferably used since the emulsifying dispersibility of the acid-modified ethylene polymer (E) is further improved.

  The amount of the monomer (B) used is 1 part by mass or more and 40 parts by mass or less, preferably 6 parts by mass or more and 32 parts by mass or less, with respect to 100 parts by mass of the ethylene polymer (A), and the monomer (b1) is It is preferably 1 to 10 parts by mass and the (meth) acrylic acid alkyl ester (b2) is preferably 0 to 30 parts by mass.

  The amount of the monomer (b1) used is 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the ethylene-based polymer (A), and 1 part by mass or more 10 When the amount is less than or equal to parts by mass, sufficient acidity can be imparted to the acid-modified ethylene polymer, and emulsification and dispersion can be performed. When the amount is 2 parts by mass or more and 10 parts by mass or less, the emulsification dispersibility is further improved. Moreover, compared with the case where there are more than 10 mass parts, when it is 1 mass part or more and 10 mass parts or less, since bridge | crosslinking at the time of acid modification does not advance easily, gelatinization is suppressed and emulsification dispersibility becomes favorable. preferable. When the amount is 2 parts by mass or more and 8 parts by mass or less, the emulsification dispersibility is further improved.

  The amount of the (meth) acrylic acid alkyl ester (b2) used is 0 to 30 parts by mass and 4 to 24 parts by mass with respect to 100 parts by mass of the ethylene polymer (A). preferable. Compared with the case where (meth) acrylic acid alkyl ester (b2) is not used, when 30 parts by mass or less is used, the copolymerization with the grafted monomer (b1) proceeds, and the ethylene polymer (A ) And the carboxylic acid and / or carboxylic anhydride are efficiently introduced as a graft chain, and emulsification and dispersion can be performed. Furthermore, when the amount is 4 parts by mass or more and 24 parts by mass or less, carboxylic acid and / or carboxylic acid anhydride is more efficiently introduced into the graft chain, which facilitates emulsification and dispersion. Moreover, compared with the case where there are more than 30 mass parts, when it is 30 mass parts or less, since bridge | crosslinking at the time of acid modification does not advance easily, gelatinization is suppressed and emulsification dispersibility becomes preferable. When the amount is 4 parts by mass or more and 24 parts by mass or less, the emulsion dispersibility is further improved, which is more preferable.

  In this invention, unless the effect of this invention is inhibited, ethylenically unsaturated compounds other than the said monomer (b1) and (meth) acrylic-acid alkylester (b2) can also be used simultaneously. Examples of the ethylenically unsaturated compound include styrene monomers such as styrene, α-methylstyrene and divinylbenzene, olefins such as ethylene, propylene and butene, alkadienes such as butadiene and isoprene, isobutyl vinyl ether, dodecyl vinyl ether and cyclohexyl vinyl ether. , Vinyl ethers such as diethylene glycol monovinyl ether and 4-hydroxybutyl vinyl ether. These ethylenically unsaturated compounds may be used alone or in combination of two or more.

  The mercaptans (C) are specifically n-butyl mercaptan, t-butyl mercaptan, n-pentyl mercaptan, n-hexyl mercaptan, n-octyl mercaptan, t-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan. Alkyl mercaptans such as stearyl mercaptan, methyl mercaptopropionate, ethyl mercaptopropionate, propyl mercaptopropionate, butyl mercaptopropionate, methoxybutyl mercaptopropionate, n-octyl mercaptopropionate, 2-ethylhexyl mercaptopropionate, thiol Methyl glycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, methoxybutyl thioglycolate, thioglycol At least one of alkyl mercapto alkylates such as n-octyl oxalate and 2-ethylhexyl thioglycolate, aryl mercaptans such as benzenethiol and toluenethiol, thiocarboxylic acids such as thiosalicylic acid, and mercapto alcohols such as mercaptoethanol These may be used alone or in combination of two or more. It is preferably at least one mercaptan selected from alkyl mercaptan and alkyl mercapto alkylate because it has no reactive group other than thiol and is a non-aromatic compound. In order to facilitate the grafting reaction by hydrogen abstraction, a reaction at a high temperature is preferable. Therefore, n-octyl mercaptan, n-decyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan having a boiling point of 150 ° C. or higher, It is more preferable to use mercaptans such as stearyl mercaptan, 2-ethylhexyl mercaptopropionate, and n-octyl mercaptopropionate.

  The amount of mercaptans (C) used is 0.01 to 2 parts by mass and 0.1 to 1.0 parts by mass with respect to 100 parts by mass of the ethylene polymer (A). Is preferred. When the content is 0.01 parts by mass or more and 2 parts by mass or less compared to the case where the content is less than 0.01 parts by mass, it is difficult for the ethylene-based polymer to crosslink during the acid modification reaction, and the MFR change rate Is suppressed, and it becomes easy to carry out emulsification dispersion by becoming an acid-modified ethylene polymer having high fluidity. Furthermore, when it is 0.1 mass part or more and 1.0 mass part or less, since the fall of MFR change rate is suppressed more and it becomes easy to carry out emulsification dispersion | distribution, it is preferable. In addition, when the amount is 0.01 parts by mass or more and 2 parts by mass or less as compared with the case where the amount is more than 2 parts by mass, the monomer (b1) and (meta) not grafted to the ethylene polymer due to the chain transfer effect of mercaptan ) Generation of by-products generated by copolymerization of acrylic acid alkyl ester (b2) can be suppressed. Further, in the case of 0.1 parts by mass or more and 1.0 part by mass or less, the occurrence is caused by copolymerization of the monomer (b1) not grafted to the ethylene polymer and the (meth) acrylic acid alkyl ester (b2). This is preferable because generation of by-products is further suppressed.

  The radical generator of the organic peroxide (D) may be a peroxide having a carbon atom in the skeleton of the compound, and is preferably a peroxide capable of generating a radical having a hydrogen abstracting effect. Oxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, peroxydicarbonates, alkylperoxycarbonates, specifically, diisobutyryl peroxide, cumyl peroxyneodecanate , Di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, di (4-t- Butylcyclohexyl Peroxydicarbonate, 1-cyclohexyl-1-methylethyl peroxyneodecanate, di (2-ethoxyethyl) peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, t-hexyl peroxyneodecanate , Dimethoxybutyl peroxydicarbonate, t-butyl peroxyneodecanate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di (3,3,5-trimethylhexanoyl) peroxide, di-n -Octanoyl peroxide, dilauroyl peroxide, distearoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanate, disuccinic acid peroxide, 2,5-dimethyl-2,5-di (2 − Tylhexanoyl peroxy) hexane, t-hexyl peroxy-2-ethylhexanate, di (4-methylbenzoyl) peroxide, t-butyl peroxy-2-ethylhexanate, dibenzoyl peroxide, t-butyl peroxyisobuty 1,1-di (t-butylperoxy) -2-methylcyclohexanate, 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexanate, 1,1- Di (t-butylperoxy) cyclohexane, 1,1-di (t-hexylperoxy) cyclohexane, 2,2-di (4,4-di- (t-butylperoxy) cyclohexane) propane, t-hexyl Peroxy isopropyl monocarbonate, t-butyl peroxy maleic acid, t- Butyl peroxy-3,3,5-trimethylhexanate, t-butyl peroxylaurate, 2,5-dimethyl-2,5-di (3-methylbenzoylperoxy) hexane, t-butyl peroxyisopropyl monocarbonate , T-butyl peroxy-2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butyl peroxyacetate, 2,2-di- (T-butylperoxy) butane, t-butylperoxybenzoate, n-butyl 4,4-di- (t-butylperoxy) valerate, di (2-t-butylperoxyisopropyl) benzene, dicumyl peroxide , Di-t-hexyl peroxide, 2,5-dimethyl -2,5-di (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3 -Tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-butyl hydroperoxide and the like. These may be used individually by 1 type, and may be used in combination of 2 or more types.

  The amount of the organic peroxide (D) used is 0.05 parts by mass or more and 0.5 parts by mass or less, particularly 0.1 parts by mass or more and 0.3 parts by mass or less with respect to 100 parts by mass of the ethylene polymer (A). It is preferable that Addition of monomer (b1) and (meth) acrylic acid alkyl ester (b2) when the content is 0.1 parts by mass or more and 0.5 parts by mass or less compared to the case where the content is less than 0.05 parts by mass It is preferable because the reaction efficiency is improved, and when it is 0.1 part by mass or more and 0.3 part by mass or less, the reaction efficiency is further improved. In addition, when the amount is 0.5 parts by mass or less compared to the case where the amount is more than 0.5 parts by mass, crosslinking of the ethylene polymer at the time of the acid modification reaction is suppressed, emulsification dispersion is improved, and adhesion, The effect is improved when surface modification or the like is performed, and the content is preferably 0.1 parts by mass or more and 0.3 parts by mass or less. This is preferable because crosslinking is further suppressed and the effect is improved.

  The method for acid-modifying the ethylene polymer (A) can be carried out by a known method. For example, the ethylene polymer (A) is brought to a temperature higher than the softening point, and the monomer (B) and mercaptans (C ) And a melt method for obtaining an acid-modified ethylene polymer grafted with an organic peroxide (D), or dissolving the ethylene polymer (A) in an organic solvent to prepare a monomer (B) and a mercaptan. A solution method to obtain an acid-modified ethylene polymer grafted with an organic peroxide (D), and an ethylene polymer (A), a monomer (B) and a mercaptan (C ) And an organic peroxide (D) using a Banbury mixer, a kneader, an extruder, or the like, and a method of kneading at a temperature equal to or higher than the softening point of the ethylene polymer (A). As addition method of monomer (B), mercaptans (C) and organic peroxide (D), batch addition, addition after diluting into solution, divided addition, continuous addition method by dropping, etc. can be appropriately selected, The order of addition can also be selected as appropriate. The acid-denaturing reaction may be performed in multiple stages, and in this case, each reactor and reaction type can be used in appropriate combination. In addition, a decompression step can be provided at the end of the reaction to remove residual monomers (B), mercaptans (C), organic peroxide (D), decomposition products of organic peroxide (D), and organic solvents.

  When the ethylene polymer (A) is acid-modified with the monomer (B) by the solution method, examples of the organic solvent include saturated aliphatic hydrocarbons such as hexane, heptane, and octane, cyclohexane, methylcyclohexane, and ethylcyclohexane. , Saturated alicyclic hydrocarbons such as cycloheptane and methylcycloheptane, alkylene glycol alkyl ether alkylates such as ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate and propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether Dialkylene glycol alkyl ether alkylates such as acetate, diethylene glycol monobutyl ether acetate, ethyl acetate, propyl acetate, butyrate , Ethyl esters such as ethyl propionate, propyl propionate, butyl propionate, ethyl butyrate, propyl butyrate, butyl butyrate, and the like, ethyl esters such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, etc. Examples thereof include ketones not containing a heavy bond, ethers not containing an ethylenic double bond such as n-butyl ether, isobutyl ether, tetrahydrofuran, diethyl ether, ethylene glycol dialkyl ether, and dioxane. Aromatic hydrocarbons that do not contain ethylenic double bonds such as toluene, xylene, and ethylbenzene can also be used, but it is preferable not to use them as much as possible due to recent environmental problems. These organic solvents may be used alone or in combination.

  In the acid-modified ethylene polymer obtained as described above, a stabilizer for adjusting the stability can be added in the acid-modifying reaction according to the purpose of use. Examples of the stabilizer include sorbitol, sorbitol alkylate, hydroquinone, benzoquinone, nitrosophenylhydroxy compound, phosphite compounds such as tris (2,4-di-t-butylphenyl) phosphite, pentaerythrityl-tetrakis [3- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate] and other compounds such as pentaerythritol esters. These may be used individually by 1 type, and may be used in combination of 2 or more types.

  Although there is no restriction | limiting in particular in the reaction temperature which acid-modifies ethylene-type polymer (A), 100 to 200 degreeC is preferable. The temperature is preferably higher than the temperature at which the ethylene polymer melts or dissolves in the organic solvent so that the monomer (B), mercaptans (C) and organic peroxide (D) can be uniformly dispersed. It is preferable to carry out at 100 ° C. or higher. Moreover, it is preferable that the temperature is not excessively high in order to suppress a decrease in the molecular weight of the ethylene polymer due to thermal degradation, and specifically, it is preferably performed at 200 ° C. or lower.

  The acid-modified ethylene polymer can neutralize the carboxyl group derived from the monomer (B) with a basic substance and disperse in water using an emulsifier or a protective colloid to obtain an acid-modified ethylene polymer aqueous dispersion. . Moreover, the thing in which the organic solvent was contained in water can also be used as a dispersion medium. As an emulsification method, a solution obtained by dissolving an acid-modified ethylene polymer in an oil-soluble solvent is neutralized with a basic substance, an emulsifier, a protective colloid and water are mixed, treated with a homogenizer, and then the solvent is distilled off. So-called solvent method for producing oil-in-water emulsion, so-called mechanical method for producing oil-in-water emulsion through homogenizer by mixing melted ethylene polymer resin and basic substance, emulsifier, protective colloid and water at high temperature, under high temperature So-called melted ethylene polymer resin and basic substance, emulsifier, protective colloid and some water are mixed to form a water-in-oil emulsion, and then inversion water is added to make a phase transition to an oil-in-water emulsion. A phase inversion method is used. Moreover, the mechanical method which forms an oil-in-water-type emulsion using a high shear type | mold rotary emulsification disperser can also be used.

  The acid-modified ethylene polymer may be neutralized with a basic substance, and then dispersed in water without using an emulsifier or a protective colloid to form an emulsifier-less acid-modified ethylene polymer aqueous dispersion. Moreover, the thing in which the organic solvent was contained in water can also be used as a dispersion medium. As an emulsification method, a solution in which an acid-modified ethylene polymer is dissolved in an oil-soluble solvent, a basic substance, and water are mixed, and after homogenizer treatment, the solvent is distilled off to produce an oil-in-water emulsion. Method, so-called mechanical method of mixing oil-in-water emulsion through a homogenizer, mixing molten ethylene polymer, basic substance and water at high temperature, mixing molten ethylene polymer resin, basic substance and water at high temperature Then, a so-called phase inversion method is used in which a water-in-oil emulsion is formed, and then inversion water is added to cause phase transition to the oil-in-water emulsion. Moreover, the mechanical method which forms an oil-in-water-type emulsion using a high shear type | mold rotary emulsification disperser can also be used.

  When the acid-modified ethylene polymer is dispersed in water, the carboxyl group derived from the monomer (B) can be neutralized with a basic substance. Basic substances include alkali metals such as sodium hydroxide and potassium hydroxide, alkaline earth metals such as calcium hydroxide, ammonium, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, ethanolamine, isopropylamine Organic amine compounds such as propanolamine, 2-methyl-2-aminopropanol, diethanolamine, N, N-dimethylethanolamine, N-methyldiethanolamine, dimethylamine, triethylamine, morpholine, N-methylmorpholine, N-ethylmorpholine 1 type or 2 types or more can be used.

  The reason why the basic substance is added is to neutralize and ionize the carboxyl group to improve the dispersion in water. The electric repulsion between the carboxyl anions generated by the neutralization prevents aggregation between the fine particles and imparts the stability of the aqueous dispersion.

  As the dispersion medium, only water or a mixed solvent of an organic solvent and water can be used. As the organic solvent, a solvent which is soluble in water at 20 ° C. at a pressure of 2.5% by mass or more is preferable. Methanol, ethanol, n-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol, t-butanol , Alcohols such as 1-pentanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether and tetrahydrofuran, cellosolves such as 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol, ethylene glycol, propylene Examples include alkylene glycols such as glycol and diethylene glycol, and polyhydric alcohols such as glycerin. These organic solvents may be used alone or in combination. Of these, alcohols and cellosolves that are soluble in water by 5% by mass or more are preferable, and 1-butanol, 2-butanol, and 2-butoxyethanol are more preferable.

  In addition, since it is preferred that the organic solvent is not contained as much as possible due to environmental problems in recent years, the amount of the organic solvent remaining in the aqueous dispersion may be 50 parts by mass or less with respect to 100 parts by mass of the acid-modified ethylene polymer. preferable. Compared with the case where the amount is more than 50 parts by mass, the amount of 50 parts by mass or less is preferable because the content of the organic solvent in the acid-modified polyolefin resin aqueous dispersion is reduced.

  As an emulsifier for acid-modified ethylene polymer, polyoxyethylene lauryl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene alkyl ether such as polyoxyethylene nonyl phenyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sorbitan mono Nonionic surfactants such as polyoxyethylene sorbitan fatty acid esters such as laurate and polyoxyethylene sorbitan monooleate, sorbitan fatty acid esters, lauryl sulfate and lauryl sulfate (hereinafter, acids and salts are abbreviated as acids) ), Dodecylbenzenesulfonic acid (salt), dialkylsulfosuccinic acid (salt), polyoxyethylene alkyl ether sulfuric acid (salt), polyoxyethylene alkyl phenyl ether sulfuric acid Salts), fatty acids (salts), anionic surface active agents such as alkenyl succinic acid (salts), also include surfactants of the cationic and amphoteric. Here, the salt represents an alkali metal salt such as sodium salt or potassium salt, an alkaline earth metal salt such as calcium salt, an ammonium salt, or an amine salt such as triethylamine salt.

  Examples of the protective colloid of the acid-modified ethylene polymer include polyvinyl alcohol, polyethylene glycol, polyacrylamide, starch, and carboxymethyl cellulose. These emulsifiers and protective colloids can be used alone or in combination of two or more.

  The pH of the aqueous dispersion is not particularly limited, but is preferably 6 to 11, and more preferably 7 to 9. When the pH of the aqueous dispersion is 6 to 11, since the carboxyl group in the acid-modified ethylene polymer is neutralized and ionized to improve the dispersion in water, the storage stability of the aqueous dispersion is better. Yes, it is more preferable that the pH is 7 to 9, since neutralization of carboxyl groups in the acid-modified ethylene polymer proceeds and the storage stability of the aqueous dispersion becomes good. On the other hand, when the pH of the aqueous dispersion is 6 to 11, it is preferable because the free basic substance is not excessively present in the aqueous dispersion, so that the adhesion and water resistance of the coating film are improved. In the case of -9, since a free basic substance further reduces in an aqueous dispersion and the adhesiveness of a coating film and water resistance become favorable, it is more preferable. Further, when an organic amine is used, the amine odor can be suppressed by suppressing the free base, and this is preferable because there is less restriction due to odor when used in applications such as paints and inks such as aqueous coating compositions.

  In addition, when the aqueous dispersion is prepared by the solvent method, the solvent for dissolving the acid-modified ethylene polymer is an aromatic hydrocarbon such as toluene or xylene, or an aliphatic carbon such as hexane, heptane or octane. Hydrogen, cycloaliphatic hydrocarbons such as cyclohexane, methylcyclohexane, cycloheptane, etc., esters such as ethyl acetate, n-butyl acetate, isobutyl acetate, and amine acetate, ethers such as n-butyl ether and isobutyl ether, acetone , Ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone can be used.

  The solid content concentration of the acid-modified ethylene polymer aqueous dispersion is not particularly limited, but it is preferable that the solid content concentration is 1% by mass or more and 50% by mass or less as an easy-to-handle dispersion. % Or less is more preferable.

  The acid-modified ethylene polymer aqueous dispersion may contain a stabilizer, an additive, a pigment, a filler, and the like. In this case, the stabilizer, the additive, the pigment, the filler, and the like are dissolved in water. Or may be dispersed.

  The acid-modified ethylene polymer and the acid-modified ethylene polymer aqueous dispersion thus obtained can be used as, for example, a paint binder, an ink binder, and a primer, and particularly when coating an ethylene polymer resin or composite material. In addition, adhesion and paintability are excellent. Further, it can be used as a heat sealant, an adhesive, and an adhesive modifier, and has excellent adhesiveness particularly in adhesion between an ethylene polymer resin or composite material and other resins, metals, glass, or the like. In addition, when making ethylene polymer resins and composite materials such as films, sheets, structural materials, building materials, automobile parts, electrical / electronic products, and packaging materials, ethylene polymer resins and other resins It can also be used as a compatibilizer, a modifier such as a dispersant that makes it easy to disperse the composite material in the ethylene polymer, and a glass fiber sizing agent.

  Specific examples of the method for producing the acid-modified ethylene polymer of the present invention and the aqueous dispersion of the acid-modified ethylene polymer are shown below. In addition, this invention is not limited only to these Examples. In the following, “part” and “%” are all based on mass unless otherwise specified.

<MFR and MFR change rate of ethylene polymer and acid-modified ethylene polymer>
The MFR of the ethylene-based polymer and the acid-modified ethylene-based polymer in Examples and Comparative Examples is a value obtained by measurement using a flow tester (manufactured by Shimadzu Corporation: CFT-500D). The load was 0.49 MPa, and the die was measured at an inner diameter × length = 1 mm × 10 mm at 190 ° C. In addition, MFR change rate is calculated | required with the following formula | equation, and gelation may arise that MFR change rate is 30% or less.
(MFR change rate) =
(MFR of acid-modified ethylene polymer (E)) / (ethylene polymer (A) MFR) × 100

<Melting point of ethylene polymer and acid-modified ethylene polymer>
The melting points of the ethylene polymer and the acid-modified ethylene polymer in the examples and comparative examples are detected during the temperature raising program using a differential scanning calorimeter (DSC) (DSC22 manufactured by Seiko Instruments Inc.). The temperature at the peak top of the main endothermic peak.

<Molecular weight of ethylene polymer and acid-modified ethylene polymer>
In Examples and Comparative Examples, the molecular weights of ethylene polymers and acid-modified ethylene polymers were measured using gel permeation chromatography (manufactured by Tosoh Corporation: HLC-8120GPC, developing solvent THF, standard material polystyrene). The weight average molecular weight (Mw) was defined as the molecular weight.

  In addition, what corresponds to Table 1 was used as an ethylene polymer (A) of an Example and a comparative example.

  As the monomer (b1) of Examples and Comparative Examples, maleic anhydride (MAn) and fumaric acid (FA) were used.

  Examples of (meth) acrylic acid alkyl ester (b2) for Examples and Comparative Examples include 2-ethylhexyl acrylate (EHA), cyclohexyl methacrylate (CHMA), i-butyl acrylate (iBA), stearyl methacrylate (SMA), lauryl methacrylate ( LMA) was used.

  As mercaptans (C) for Examples and Comparative Examples, n-dodecyl mercaptan (NDM), thiosalicylic acid (TSA), mercaptoethanol (MET), n-octyl mercaptopropionate (MPAO), n-octyl mercaptan (NOM) )It was used.

  As organic peroxides (D) for Examples and Comparative Examples, di-t-butyl peroxide (Nippon Yushi Co., Ltd .: Perbutyl D: PBD), di-t-hexyl peroxide (Nippon Yushi Co., Ltd .: Perhexyl D: PHD), t-butyl peroxy 2-ethylhexyl monocarbonate (manufactured by NOF Corporation: perbutyl E: PBE), dicetyl peroxydicarbonate (manufactured by Akzo Nobel: DCPDC) were used.

(Example 1) Production of an acid-modified ethylene polymer (E-1).
In a 300 ml Separa flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube, 100 parts by mass of ethylene polymer (A-1), Irganox 1010 as a stabilizer (trade name: Ciba Geigy Corporation (I-1010) ) 0.1 part by mass and Irgafos 168 (trade name: manufactured by Ciba Geigy (I-168)) 0.1 part by mass, xylene (Xy) 15 parts by mass in an oil bath maintained at 180 ° C. under a nitrogen atmosphere The temperature of the oil bath was adjusted so that the temperature in the system was 170 ° C. while stirring. After the system melts, while stirring to obtain a uniform state, maleic anhydride (MAn) 2 parts by mass, 2-ethylhexyl acrylate (EHA) 6 parts by mass, n-dodecyl mercaptan (NDM) 0.2 part by mass, 0.1 part by mass of di-t-butyl peroxide (PBD) was added. The reaction was continued for 30 minutes while maintaining the system at 170 ° C., then 2 parts by weight of maleic anhydride (MAn), 6 parts by weight of 2-ethylhexyl acrylate (EHA) and 0.2 parts by weight of n-dodecyl mercaptan (NDM) Part and 0.1 part by mass of di-t-butyl peroxide (PBD) were added. In the same manner, maleic anhydride (MAn), 2-ethylhexyl acrylate (EHA), n-dodecyl mercaptan (NDM) and di-t-butyl peroxide (PBD) were added every 30 minutes for a total of 5 times. The total addition amount of acid (MAn) is 10 parts by mass, the total addition amount of 2-ethylhexyl acrylate (EHA) is 30 parts by mass, the total addition amount of n-dodecyl mercaptan (NDM) is 1.0 part by mass, The total amount of di-t-butyl peroxide (PBD) added was 0.5 parts by mass.
After completion of the addition, the reaction was carried out for 1.5 hours while maintaining the system at 170 ° C., and then, while reducing the pressure in the flask with an aspirator, xylene, unreacted maleic anhydride, 2-ethylhexyl acrylate, di-t- Removal of low molecular weight compounds in which butyl peroxide and di-t-butyl peroxide are decomposed is performed for 1 hour, and after completion of the pressure reduction, the reaction product is taken out and cooled, thereby acid-modified ethylene modified with unsaturated carboxylic acids. A solid of the polymer (E-1) was obtained. MFR (190 degreeC) of the obtained acid-modified ethylene polymer (E-1) was 191 g / 10min. From the raw material ethylene polymer (A-1), the MFR change rate was changed to 147%.

(Example 2) Production of an acid-modified ethylene polymer (E-2).
In a 300 ml Separ flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 100 parts by mass of ethylene polymer (A-2), 0.1 part by mass of sorbitol (Sor) as stabilizer, propylene glycol 5 parts by mass of monomethyl ether acetate (PMA) was added, melted in an oil bath maintained at 190 ° C. under a nitrogen atmosphere, and the temperature of the oil bath was adjusted to 180 ° C. while stirring. . After the system melts, while stirring to obtain a uniform state, maleic anhydride (MAn) 5 parts by mass, thiosalicylic acid (TSA) 0.3 part by mass and di-t-butyl peroxide (PBD) 0.15 A monomer solution in which 15 parts by mass of propylene glycol monomethyl ether acetate (PMA) was dissolved in mass parts was added dropwise over 1 hour. The solvent was used in an amount of 20 parts by mass, including 5 parts by mass before addition and 15 parts by mass of diluted monomer.
After completion of the dropwise addition, the reaction was carried out for 1 hour while maintaining the system at 180 ° C., and then propylene glycol monomethyl ether acetate, unreacted maleic anhydride, di-t-butyl peroxide while reducing the pressure in the flask with an aspirator. And a low molecular weight compound in which di-t-butyl peroxide is decomposed is removed for 1 hour, and after completion of the decompression, the reaction product is taken out and cooled, so that the acid-modified ethylene polymer is acid-modified with unsaturated carboxylic acids. A solid of (E-2) was obtained. The acid-modified ethylene polymer (E-2) obtained had an MFR (190 ° C.) of 5.1 g / 10 min. From the raw material ethylene polymer (A-2), the MFR change rate was reduced to 36%.

(Example 3) Production of an acid-modified ethylene polymer (E-3).
In a 300 ml Separa flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube, 100 parts by mass of (A-3) ethylene polymer, 0.1 part by mass of sorbitol (Sor) as a stabilizer, Melting was carried out in an oil bath maintained at 180 ° C. in a nitrogen atmosphere, and the temperature of the oil bath was adjusted so that the temperature in the system was 170 ° C. while stirring. After the inside of the system melts, while stirring to obtain a uniform state, maleic anhydride (MAn) 1 part by mass, mercaptoethanol (MET) 0.01 part by mass and di-t-butyl peroxide (PBD) 0.05 Part by weight was added.
After the addition, the reaction was carried out for 1 hour while maintaining the system at 170 ° C., and then the unreacted maleic anhydride, di-t-butyl peroxide and di-t-butyl permeate were reduced while reducing the pressure in the flask with an aspirator. The removal of the low molecular weight compound in which the oxide was decomposed was performed for 1 hour, and after completion of the decompression, the reaction product was taken out and cooled to solidify the acid-modified ethylene polymer (E-3) acid-modified with unsaturated carboxylic acids. I got a thing. MFR (190 degreeC) of the obtained acid-modified ethylene polymer (E-3) was 344 g / 10min. From the raw material ethylene polymer (A-3), the MFR change rate decreased to 41%.

(Example 4) Production of an acid-modified ethylene polymer (E-4).
Implemented except changing the type and amount of ethylene polymer (A), monomer (b1), (meth) acrylic acid alkyl ester (b2), mercaptans (C) and organic peroxide (D) according to Table 2. In the same manner as in Example 2, an acid-modified ethylene polymer (E-4) was obtained. The solvent was used in an amount of 20 parts by mass, including 5 parts by mass before addition and 15 parts by mass of diluted monomer. MFR (190 degreeC) of the obtained acid-modified ethylene polymer (E-4) is 0.5 g / 10min. From the raw material ethylene polymer (A-4), the MFR change rate decreased to 63%.

(Example 5) Production of an acid-modified ethylene polymer (E-5).
The type and amount of ethylene polymer (A), monomer (b1), (meth) acrylic acid alkyl ester (b2), mercaptans (C) and organic peroxide (D) were changed according to Table 2, and the solvent was changed. An acid-modified ethylene polymer (E-5) was obtained in the same manner as in Example 1 except that xylene was changed to ethylcyclohexane (ECH). The acid-modified ethylene polymer (E-5) obtained had an MFR (190 ° C.) of 6.1 g / 10 min. From the raw material ethylene polymer (A-2), the MFR change rate decreased to 44%.

(Example 6) Production of an acid-modified ethylene polymer (E-6).
The type and amount of ethylene polymer (A), monomer (b1), (meth) acrylic acid alkyl ester (b2), mercaptans (C) and organic peroxide (D) were changed according to Table 2, The solvent added to the polymer (A) is 5 parts by mass of butyl propionate (PAB), the temperature in the flask during acid modification is 170 ° C., and the solvent for dissolving the monomers is 15 parts by mass of butyl propionate. Produced an acid-modified ethylene polymer (E-6) in the same manner as in Example 2. The solvent was used in an amount of 20 parts by mass, including 5 parts by mass before addition and 15 parts by mass of diluted monomer. The resulting acid-modified ethylene polymer (E-6) had an MFR (190 ° C.) of 13 g / 10 min. From the raw material ethylene polymer (A-2), the MFR change rate was reduced to 93%.

(Example 7 to Example 9, Comparative Example 1, Comparative Example 2, Comparative Example 4 to Comparative Example 7) Acid-modified ethylene polymers (E-7) to (E-11), (E-13) to ( Production of E-16).
The type and amount of ethylene polymer (A), monomer (b1), (meth) acrylic acid alkyl ester (b2), mercaptans (C), and organic peroxide (D) were changed according to Table 2. The acid-modified ethylene polymers (E-7) to (E-11), (E-13) to (E-) are the same as in Example 6 except that the solvent is propylene glycol monomethyl ether acetate (PMA). 15) was obtained. In Example 8, lauryl methacrylate (LMA) and styrene (St) were used in combination as other monomers. In Comparative Example 7, α-methylstyrene dimer (MSD) was used as a chain transfer agent in place of mercaptans (C). MFR (190 degreeC) of the obtained acid-modified ethylene polymer (E-7)-(E-11), (E-13)-(E-16) and MFR from raw material ethylene polymer (A) Table 2 shows the rate of change.

(Comparative Example 3) Production of acid-modified ethylene polymer (E-12).
The type and amount of ethylene polymer (A), monomer (b1), (meth) acrylic acid alkyl ester (b2), mercaptans (C) and organic peroxide (D) were changed according to Table 2, The solvent added to the polymer (A) is 30 parts by mass of propylene glycol monomethyl ether acetate (PMA), the temperature in the flask during acid modification is 140 ° C., and the solvent for dissolving the monomers is propylene glycol monomethyl ether acetate (PMA). ) An acid-modified ethylene polymer (E-12) was obtained in the same manner as in Example 2 except that the amount was 20 parts by mass. The solvent was used in an amount of 50 parts by mass, including 30 parts by mass before addition and 20 parts by mass of diluted monomer. The resulting acid-modified ethylene polymer (E-12) had an MFR (190 ° C.) of 9.2 g / 10 min. From the raw material ethylene polymer (A-2), the MFR change rate was reduced to 66%.

Explanation of abbreviations in Table 2:
(Parts): Mass parts I-1010: Irganox 1010
I-168: Irgafos 168
Sor: sorbitol MAn: maleic anhydride FA: fumaric acid EHA: 2-ethylhexyl acrylate CHMA: cyclohexyl methacrylate iBA: i-butyl acrylate SMA: stearyl methacrylate LMA: lauryl methacrylate NDM: n-dodecyl mercaptan TSA: thiosalicylic acid MET: mercaptoethanol MPAO: n-octyl mercaptopropionate NOM: n-octyl mercaptan PBD: di-t-butyl peroxide PHD: di-t-hexyl peroxide PBE: t-butyl peroxy 2-ethylhexyl monocarbonate DCPDC: dicetyl peroxydicar Bonate Xy: Xylene PMA: Propylene glycol monomethyl ether acetate ECH: Ethylcyclohexane PA B: Butyl propionate St: Styrene MSD: α-methylstyrene dimer (* 1) Since gelation, measurement is not possible.

(Example 10) Production of an acid-modified ethylene polymer aqueous dispersion (F-1).
In a 1000 ml Separa flask equipped with a stirrer, thermometer and reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-1) obtained in Example 1 was added, and in an oil bath maintained at 150 ° C. Melted. After melting, the oil bath was set to 120 ° C. Next, an aqueous solution in which 8.8 parts by mass of N, N-dimethylethanolamine (DMEA) is dissolved in 50 parts by mass of ion-exchanged water at 90 ° C. is applied to the melted acid-modified ethylene polymer (E-1) for 5 minutes. After adding dropwise, 250 parts by mass of 90 ° C. ion exchange water was added little by little with vigorous stirring. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding ion-exchanged water, cooling is performed, and when the internal temperature reaches 30 ° C., the content is filtered through a 100-mesh nylon filter cloth to obtain an acid-modified ethylene polymer aqueous dispersion (F-1). )
The obtained acid-modified ethylene polymer aqueous dispersion (F-1) had a solid content of 26.1%, a viscosity of 20 mPa · s (25 ° C.), a pH of 8.5, and a particle diameter (median diameter) of 220 nm. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 11) Production of an acid-modified ethylene polymer aqueous dispersion (F-2).
To a 1000 ml Separa flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-2) obtained in Example 2 and 100 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. As an emulsifier, 3 parts by mass of ammonium dodecylbenzenesulfonate (DBSA) (Newcol-210 manufactured by Nippon Emulsifier Co., Ltd.), 12 parts by mass of polyoxyethylene stearyl ether (PEGS) (Newcol-1807 manufactured by Nippon Emulsifier Co., Ltd.) were added. After adding 4.8 parts by mass of N, N-dimethylethanolamine (DMEA) and 20 parts by mass of butyl cellosolve (BC), after vigorously stirring, a total of 300 parts by mass of 90 ° C. ion exchange water was added little by little. Pre-emulsification was performed with stirring. This preliminary emulsified solution was passed through a high-pressure homogenizer (manufactured by APV Gaulin Inc) at 90 ° C. twice under a pressure of 30 MPa for emulsification. After emulsification, the temperature of the oil bath was set to 100 ° C., and toluene and butyl cellosolve were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate is 150 parts by mass, cooling is performed, and when the internal temperature is 30 ° C., the content is filtered through a 100-mesh nylon filter cloth, and an acid-modified ethylene polymer aqueous dispersion is obtained. The body (F-2) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-2) had a solid content of 29.9%, a viscosity of 420 mPa · s (25 ° C.), a pH of 8.9, and a particle diameter (median diameter) of 90 nm. 830 ppm of toluene and 45300 ppm of butyl cellosolve remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 12) Production of an acid-modified ethylene polymer aqueous dispersion (F-3).
To a 1000 ml Separ flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-3) obtained in Example 3 and 100 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. As an emulsifier, 3 parts by mass of ammonium dodecylbenzenesulfonate (DBSA), 12 parts by mass of polyoxyethylene alkyl ether (PEGL) (Newcol-2305 manufactured by Nippon Emulsifier Co., Ltd.) were added, and then N, N-dimethylethanolamine (DMEA) After adding 1.2 parts by mass and 50 parts by mass of butyl cellosolve (BC), 550 parts by mass of 90 ° C. ion-exchanged water was added little by little, followed by stirring and preliminary emulsification. While maintaining this preliminary emulsified liquid at 90 ° C., an emulsification operation was performed for 30 seconds at 10,000 rotations per minute using a universal homogenizer (manufactured by Nippon Seiki Co., Ltd.). After emulsification, the temperature of the oil bath was set to 100 ° C., and toluene and butyl cellosolve were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate has reached 300 parts by mass, cooling is performed, and when the internal temperature reaches 30 ° C., the content is filtered through a 100 mesh nylon filter cloth, and an aqueous solution of acid-modified ethylene polymer is dispersed. The body (F-3) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-3) had a solid content of 20.3%, a viscosity of 1850 mPa · s (25 ° C.), a pH of 8.0, and a particle diameter (median diameter) of 490 nm. 420 ppm of toluene and 110500 ppm of butyl cellosolve remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 13) Production of an acid-modified ethylene polymer aqueous dispersion (F-4).
To a 1000 ml Separa flask equipped with a stirrer, a thermometer and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-4) obtained in Example 4 and 200 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. As an emulsifier, 3 parts by mass of ammonium dodecylbenzenesulfonate (DBSA), 12 parts by mass of polyoxyethylene sorbitan oleate (PEGSO) (Newcol-82 manufactured by Nippon Emulsifier Co., Ltd.) were added, and then 5.9 parts by mass of triethylamine (TEA). After adding 40 parts by mass of butyl cellosolve (BC), ion-exchanged water at 90 ° C. was added little by little with vigorous stirring. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 450 mass parts of 90 degreeC ion-exchange water, it stirred and pre-emulsified. This preliminary emulsified solution was passed through a high-pressure homogenizer (manufactured by APV Gaulin Inc) at 90 ° C. twice under a pressure of 30 MPa for emulsification. After emulsification, the temperature of the oil bath was set to 100 ° C., and toluene and butyl cellosolve were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate has reached 300 parts by mass, cooling is performed, and when the internal temperature reaches 30 ° C., the content is filtered through a 100 mesh nylon filter cloth, and an aqueous solution of acid-modified ethylene polymer is dispersed. A body (F-4) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-4) had a solid content of 25.5%, a viscosity of 980 mPa · s (25 ° C.), a pH of 8.8, and a particle diameter (median diameter) of 440 nm. 620 ppm of toluene and 81800 ppm of butyl cellosolve remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 14) Production of an acid-modified ethylene polymer aqueous dispersion (F-5).
To a 1000 ml Separa flask equipped with a stirrer, a thermometer and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-5) obtained in Example 5 and 200 parts by mass of methylcyclohexane (MCH) were added. Melted in an oil bath maintained at 0 ° C. After melting, the oil bath was set to 120 ° C. As an emulsifier, 1 part by mass of ammonium dodecylbenzenesulfonate (DBSA), 5 parts by mass of sorbitan laurate (SL) (Newcol-20 manufactured by Nippon Emulsifier Co., Ltd.) were added, and then 90% 2-methyl-2-aminopropanol (AMP) ) After adding 8.4 parts by mass of aqueous solution and 15 parts by mass of isopropanol (IPA), ion exchange water at 90 ° C. was added little by little while stirring vigorously. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 430 mass parts of 90 degreeC ion-exchange water, it stirred and pre-emulsified. This preliminary emulsified solution was passed through a high-pressure homogenizer (manufactured by APV Gaulin Inc) at 90 ° C. twice under a pressure of 30 MPa for emulsification. After emulsification, the temperature of the oil bath was set to 100 ° C., and methylcyclohexane and isopropanol were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate has reached 300 parts by mass, cooling is performed, and when the internal temperature reaches 30 ° C., the content is filtered through a 100 mesh nylon filter cloth, and an aqueous solution of acid-modified ethylene polymer is dispersed. A body (F-5) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-5) had a solid content of 24.6%, a viscosity of 50 mPa · s (25 ° C.), a pH of 8.2, and a particle diameter (median diameter) of 160 nm. Methylcyclohexane remained at 2850 ppm and isopropanol remained at 130 ppm. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 15) Production of an acid-modified ethylene polymer aqueous dispersion (F-6).
To a 1000 ml Separa flask equipped with a stirrer, a thermometer and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-6) obtained in Example 6 and 100 parts by mass of methylcyclohexane (MCH) were added. Melted in an oil bath maintained at 0 ° C. After melting, the oil bath was set to 120 ° C. As an emulsifier, 3 parts by mass of polyoxyethylene polycyclic phenyl ether ammonium sulfate (PEGPSA) (Newcol-707SF manufactured by Nippon Emulsifier Co., Ltd.), 12 parts by mass of polyethylene glycol oleyl ether (PEGO) (Newcol-1204 manufactured by Nippon Emulsifier Co., Ltd.) In addition, after adding 4.8 parts by mass of N, N-dimethylethanolamine and 20 parts by mass of butyl cellosolve (BC), ion-exchanged water at 90 ° C. was added little by little while stirring vigorously. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 300 parts by mass of 90 ° C. ion-exchanged water, the temperature of the oil bath was set to 100 ° C., and methylcyclohexane and butyl cellosolve were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate is 150 parts by mass, cooling is performed, and when the internal temperature is 30 ° C., the content is filtered through a 100-mesh nylon filter cloth, and an acid-modified ethylene polymer aqueous dispersion is obtained. The body (F-6) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-6) had a solid content of 30.1%, a viscosity of 280 mPa · s (25 ° C.), a pH of 8.8, and a particle diameter (median diameter) of 150 nm. 2130 ppm of methylcyclohexane and 43800 ppm of butyl cellosolve remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 16) Production of an acid-modified ethylene polymer aqueous dispersion (F-7).
To a 1000 ml Separ flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-7) obtained in Example 7 and 50 parts by mass of methylcyclohexane (MCH) were added. Melted in an oil bath maintained at 0 ° C. After melting, the oil bath was set to 120 ° C. As an emulsifier, 1 part by mass of ammonium dodecylbenzenesulfonate (DBSA), 5 parts by mass of sorbitan stearate (SS) (Newcol-60 manufactured by Nippon Emulsifier Co., Ltd.) were added, and then 5.6 parts by mass of 28% aqueous ammonia (NH3). After adding 30 parts by mass of n-butanol (nBuOH), ion exchange water at 90 ° C. was added little by little with vigorous stirring. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 320 mass parts of 90 degreeC ion-exchange water, the temperature of the oil bath was set to 100 degreeC, and methylcyclohexane and n-butanol were distilled out of the system, decompressing the inside of a flask with an aspirator. When the distillate is 150 parts by mass, cooling is performed, and when the internal temperature is 30 ° C., the content is filtered through a 100-mesh nylon filter cloth, and an acid-modified ethylene polymer aqueous dispersion is obtained. A body (F-7) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-7) had a solid content of 29.8%, a viscosity of 1560 mPa · s (25 ° C.), a pH of 8.1, and a particle diameter (median diameter) of 220 nm. Methylcyclohexane remained at 2380 ppm and n-butanol remained at 1050 ppm. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 17) Production of an acid-modified ethylene polymer aqueous dispersion (F-8).
To a 1000 ml Separa flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-8) obtained in Example 8 and 100 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. While adding 10 parts by mass of sorbitan stearate (SS) as an emulsifier, then adding 5.8 parts by mass of N, N-dimethylethanolamine (DMEA) and 20 parts by mass of 2-butanol (2BuOH) , 90 degreeC ion-exchange water was added little by little. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 290 parts by mass of 90 ° C. ion exchange water, the temperature of the oil bath was set to 100 ° C., and toluene and 2-butanol were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate is 150 parts by mass, cooling is performed, and when the internal temperature is 30 ° C., the content is filtered through a 100-mesh nylon filter cloth, and an acid-modified ethylene polymer aqueous dispersion is obtained. A body (F-8) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-8) had a solid content of 30.2%, a viscosity of 120 mPa · s (25 ° C.), a pH of 8.1, and a particle diameter (median diameter) of 130 nm. 1880 ppm of toluene and 680 ppm of 2-butanol remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 18) Production of an acid-modified ethylene polymer aqueous dispersion (F-9).
To a 1000 ml Separ flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-9) obtained in Example 9 and 100 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. As an emulsifier, 1 part by weight of ammonium dodecylbenzenesulfonate (DBSA), 5 parts by weight of polyoxyethylene stearyl ether (PEGS) are added, and then 4.8 parts by weight of N, N-dimethylethanolamine (DMEA) and butyl cellosolve (BC). After adding 20 parts by mass, ion exchange water at 90 ° C. was added little by little with vigorous stirring. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 380 mass parts of 90 degreeC ion-exchange water, it stirred and pre-emulsified. This preliminary emulsified solution was passed through a high-pressure homogenizer (manufactured by APV Gaulin Inc) at 90 ° C. twice under a pressure of 30 MPa for emulsification. After emulsification, the temperature of the oil bath was set to 100 ° C., and toluene and butyl cellosolve were distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate is 150 parts by mass, cooling is performed, and when the internal temperature is 30 ° C., the content is filtered through a 100-mesh nylon filter cloth, and an acid-modified ethylene polymer aqueous dispersion is obtained. A body (F-9) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-9) had a solid content of 30.5%, a viscosity of 1780 mPa · s (25 ° C.), a pH of 8.5, and a particle diameter (median diameter) of 120 nm. 760 ppm of toluene and 44100 ppm of butyl cellosolve remained. Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Example 19) Production of an acid-modified ethylene polymer aqueous dispersion (F-10).
To a 1000 ml Separ flask equipped with a stirrer, a thermometer, and a reflux condenser, 100 parts by mass of the acid-modified ethylene polymer (E-9) obtained in Example 9 and 200 parts by mass of toluene (tol) were added, and 150 ° C. And melted in an oil bath kept in the water. After melting, the oil bath was set to 120 ° C. Next, after adding 4.8 parts by mass of N, N-dimethylethanolamine (DMEA) and 30 parts by mass of butyl cellosolve (BC), ion exchange water at 90 ° C. was added little by little while stirring vigorously. Although the viscosity increased, the viscosity decreased when ion-exchanged water was continuously added. After adding 300 mass parts of 90 degreeC ion-exchange water, it stirred and pre-emulsified. This preliminary emulsified solution was passed through a high-pressure homogenizer (manufactured by APV Gaulin Inc) at 90 ° C. twice under a pressure of 30 MPa for emulsification. After emulsification, the temperature of the oil bath was set to 100 ° C., and toluene was distilled out of the system while reducing the pressure in the flask with an aspirator. When the distillate has reached 300 parts by mass, cooling is performed, and when the internal temperature reaches 30 ° C., the content is filtered through a 100 mesh nylon filter cloth, and an aqueous solution of acid-modified ethylene polymer is dispersed. A body (F-10) was obtained.
The obtained acid-modified ethylene polymer aqueous dispersion (F-10) had a solid content of 30.1%, a viscosity of 3200 mPa · s (25 ° C.), a pH of 8.4, and a particle diameter (median diameter) of 350 nm. 1860 ppm of toluene and 63300 ppm of butyl cellosolve remained.
Further, the emulsion was stored at 40 ° C. for 1 week and the stability over time was confirmed. As a result, there was no particular change and the emulsion was stable. Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Comparative Examples 8 to 14) Production of acid-modified ethylene polymer aqueous dispersions (F-11) to (F-17).
Example 3 except that acid-modified ethylene polymers (E-10) to (E-16) were used as acid-modified ethylene polymers (E) as shown in Table 3 and the amount of emulsifier used was changed according to Table 3. In the same manner as in No. 18, acid-modified ethylene polymer aqueous dispersions (F-11) to (F-16) were prepared. Regarding the acid-modified ethylene polymer aqueous dispersions (F-14) and (F-16), although the dispersion was insufficient and an emulsion was not obtained, the acid-modified ethylene polymer aqueous dispersion (F-11) to Emulsions were obtained for (F-13), (F-15), and (F-17). Properties of the resulting acid-modified ethylene polymer aqueous dispersion are shown in Table 3.

(Particle size)
It is a measured value of a median diameter by a particle size distribution measuring apparatus (Nikkiso Co., Ltd .: Microtrac UPA150) by a dynamic light scattering method / laser Doppler method.

(viscosity)
It is a measured value at 25 ° C. using a Brookfield rotational viscometer (manufactured by Tokimec Co., Ltd .: VISCOMETER).

(Adhesive strength test)
The acid-modified ethylene polymer aqueous dispersion was coated on a polyethylene plate with a bar coater so that the coating thickness after drying was 10 μm. After air drying at room temperature for 30 minutes, a two-component polyurethane resin paint (Utanal (L) White, manufactured by Ohashi Chemical Industry Co., Ltd.) was applied so that the coating thickness was 100 μm. After coating, the sample was dried at 100 ° C. for 30 minutes to obtain a sample. One day after drying, the coating film was cut out at intervals of 1 cm, and using a tensile tester (Tribogear Type: HEIDON-14DR manufactured by Shinto Kagaku Co., Ltd.), the coating film was applied at a pulling speed of 100 mm / min and a pulling angle of 180 degrees. The adhesive strength was evaluated by measuring the adhesive strength, and the results obtained are shown in Table 3. Adhesiveness is so good that the numerical value of adhesive strength is high. In addition, the acid-modified ethylene polymer aqueous dispersion was not obtained (F-14) and (F-16) were not subjected to an adhesive strength test.

Explanation of abbreviations in Table 3:
tol: toluene MCH: methylcyclohexane BC: butyl cellosolve IPA: isopropanol nBuOH: n-butanol 2BuOH: 2-butanol DMEA: N, N-dimethylethanolamine TEA: triethylamine AMP: 90% 2-methyl-2-aminopropanol aqueous solution NH3: 28% ammonia aqueous solution DBSA: ammonium dodecylbenzenesulfonate (Newcol-210, manufactured by Nippon Emulsifier Co., Ltd.)
PEGS: Polyoxyethylene stearyl ether (Newcol-1807 manufactured by Nippon Emulsifier Co., Ltd.)
PEGL: Polyoxyethylene glycol alkyl ether (Newcol-2305 manufactured by Nippon Emulsifier Co., Ltd.)
PEGSO: Polyoxyethylene sorbitan oleate (Newcol-82 manufactured by Nippon Emulsifier Co., Ltd.)
SL: sorbitan laurate (Newcol-20 manufactured by Nippon Emulsifier Co., Ltd.)
PEGPSA: Polyoxyethylene polycyclic phenyl ether ammonium sulfate (Newcol-707SF, manufactured by Nippon Emulsifier Co., Ltd.)
PEGO: Polyethylene glycol oleyl ether (Newcol-1204, manufactured by Nippon Emulsifier Co., Ltd.)
SS: Sorbitan stearate (Newcol-60 manufactured by Nippon Emulsifier Co., Ltd.)
Stability ○: No change after 1 week, Δ: A small amount of upper layer precipitate is seen after 1 week. X: A large amount of upper layer precipitation is observed after 1 week.
(* 1): Dispersion failure.
(* 2): Emulsification failure.

  As shown in Table 2, the graft amount of the monomer (b1) and the (meth) acrylic acid alkyl ester (b2) in the acid-modified ethylene polymer (E) is determined based on the resulting acid-modified ethylene polymer aqueous dispersion ( Various values can be set according to the purpose of use of F).

  The particle diameter of the acid-modified ethylene polymer aqueous dispersion (F) shown in Table 3 can be seen as an index indicating emulsification. As a result, in Comparative Example 1 in which polypropylene containing no ethylene was acid-modified, the MFR change rate hardly decreased, and in Comparative Example 8, a good dispersion was obtained. However, since it is an acid-modified product of polypropylene, adhesion to polyethylene is hardly seen. In Comparative Example 2 in which no mercaptans (C) were used, the MFR change rate of the acid-modified ethylene polymer (E) was significantly reduced, and the dispersion in Comparative Example 9 was also insufficient. This is considered to be due to the fact that gelation progresses with a decrease in the MFR change rate due to crosslinking, and coarse particles are generated by a gel that is difficult to disperse. In Comparative Example 3, the solvent used is increased, and in Comparative Example 4, dicetyl peroxydicarbonate (DCPDC), which is said to easily suppress the decrease in MFR change rate, is used. It can be suppressed to some extent. However, at the same time, the grafting of the acid groups becomes insufficient, and only the acid-modified polyethylene polymer (E) in the state of insufficient dispersibility such as Comparative Examples 10 and 11 is obtained. In Comparative Example 5 in which the amount of mercaptans (C) used is excessive, the MFR change rate is rather increased, and an acid-modified ethylene polymer (E) having high fluidity can be obtained. However, when an aqueous dispersion was used in Comparative Example 12, the particle size was large and an unstable emulsion was obtained. This is because mercaptans existed excessively, and even if radicals are generated by hydrogen abstraction from ethylene-based polymer (A), chain transfer of radicals occurs due to the presence of a large amount of mercaptans, and grafting by monomers proceeds. This is because an acid cannot be added to the ethylene polymer because it hardly occurs, resulting in an acid-modified product that is difficult to emulsify. Further, in Comparative Example 6 in which the organic peroxide is excessive, the suppression effect of the MFR change rate by the mercaptans cannot catch up, and the decrease in the MFR change rate of the ethylene-based polymer (A) proceeds excessively, and the gel cannot be dispersed. It became a state. In addition, α-methylstyrene dimer (MSD) is known as a continuous transfer agent similar to mercaptans (C) in radical polymerization, but when used as an alternative to mercaptans (C) in the acid modification reaction of the present invention. The effect of suppressing the MFR change rate as in mercaptans (C) was hardly observed, and Comparative Example 14 in which an aqueous dispersion was used also had the same results as Comparative Example 8 in which no mercaptans (C) were used. However, in the examples, the MFR change rate is not reduced to 30% or less in any case, and thus the decrease in the MFR change rate is suppressed. Moreover, since the fall of the MFR change rate was suppressed, fluidity | liquidity was maintained, the gel generation | occurrence | production by bridge | crosslinking was also suppressed, and the favorable emulsifiability is shown. Moreover, the aqueous dispersion which shows favorable adhesiveness with a polyethylene base material was obtained because the favorable acid-modified ethylene polymer aqueous dispersion (F) was obtained.

  According to the method for producing an acid-modified ethylene polymer of the present invention and an acid-modified ethylene polymer aqueous dispersion, an acid-modified ethylene polymer in which a decrease in MFR change rate is suppressed can be obtained, and the resulting acid-modified ethylene The system polymer can be a good aqueous dispersion having a fine particle size. Further, since the acid-modified ethylene polymer aqueous dispersion obtained by the production method of the present invention has excellent adhesion to polyethylene, it can be used for paints, ink binders, paint binders, primers, etc. It can be considered that adhesion and paintability are excellent when coating resin or composite material. It can also be used for adhesives, heat sealing agents, glass fiber sizing agents, and the like. It can be considered that it can be used for various purposes in a wide range where the above-mentioned general-purpose ethylene polymer resin aqueous dispersion is used.

Claims (5)

For 100 parts by mass of the following ethylene polymer (A), at least 1 to 40 parts by mass of the following monomer (B) and 0.01 to 2 parts by mass of mercaptans (C) are blended, and an organic peroxide ( D) A method for producing an acid-modified ethylene polymer grafted using 0.05 to 0.5 parts by mass.
(A) an ethylene polymer having a structural unit derived from at least ethylene (B) at least one unsaturated group and at least one functional group selected from a carboxyl group, an acid anhydride group, and a carboxylic acid ester group Monomer with   The method for producing an acid-modified ethylene polymer according to claim 1, wherein the ethylene polymer (A) contains at least 40 mass% of a structural unit derived from ethylene.   The method for producing an acid-modified ethylene polymer according to claim 1 or 2, wherein the mercaptans (C) are alkyl mercaptans and / or alkyl mercapto alkylates.   1 to 40 parts by mass of the monomer (B) have 1 to 10 parts by mass of the monomer (b1) having at least one unsaturated group and at least one functional group selected from a carboxyl group and an acid anhydride group; Acrylic acid ester (excluding a monomer corresponding to the monomer (b1)) (b2) (b2) 0 to 30 parts by mass, which is a monomer having a saturated group and a carboxylic acid ester group. 4. The method for producing an acid-modified ethylene polymer according to any one of 3 above.   An acid-modified ethylene polymer containing an acid-modified ethylene polymer, a basic compound, and an aqueous medium obtained by the method for producing an acid-modified ethylene polymer according to any one of claims 1 to 4. Aqueous dispersion.