JP2006257192A - Aqueous emulsion and its manufacturing process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process of an aqueous emulsion for adhesives which is manufactured easily with a high reproducibility and has an excellent thermal creep resistance. <P>SOLUTION: In a manufacturing process to obtain an aqueous emulsion by emulsion-polymerizing monomers in the presence of a polyurethane aqueous emulsion, at least ethylene, a vinyl ester and a multifunctional monomer are used for the monomers, the emulsion-polymerization is carried out using a redox catalyst. An erythorbic acid and/or an ascorbic acid are used together with a salt of a transition metal for the reduction agent for the redox catalyst. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aqueous emulsion suitable for an adhesive such as polyolefin and a method for producing the same. More specifically, the present invention relates to an aqueous emulsion obtained by further polymerizing ethylene, vinyl acetate and the like using a polyurethane aqueous emulsion as a seed and a method for producing the same.

Patent Document 1 discloses an adhesive composition containing a specific ethylene-vinyl acetate-polyfunctional monomer copolymer aqueous emulsion and an aqueous polyurethane emulsion as an adhesive composition excellent in normal adhesiveness and heat-resistant creep resistance. Has been. And it is disclosed that this adhesive composition is suitable for adhesion | attachment of wood and a vinyl chloride sheet, and can also adhere polyolefin sheet | seats, such as polyethylene and a polypropylene, and wood.
By the way, from the viewpoint of environmental problems, the polyvinyl chloride sheet has been avoided and moved to the polyolefin sheet, and the polyolefin composition has an adhesive composition with excellent normal adhesiveness and heat-resistant creep resistance equal to or higher than that of the polyvinyl chloride sheet. Things are sought.
Recently, an adhesive composition obtained by emulsion polymerization of ethylene and vinyl acetate with ammonium persulfate using a polyurethane aqueous emulsion as a seed as an adhesive composition excellent in normal adhesiveness and heat-resistant creep resistance to a polyolefin sheet is disclosed in Patent Document 2. And a specific adhesion test method is described, but there is no specific description of adhesive properties.

JP-A-9-19481 [Claims], [0017] JP 2004-211037 A1 [Claim 1], [0035]

In order to ascertain the adhesive properties, the present inventors have found that an aqueous emulsion obtained by further emulsion polymerization of ethylene and vinyl acetate using a polyurethane aqueous emulsion as a seed and ammonium persulfate as a catalyst according to Example 1 of Patent Document 2. When production was attempted, emulsion polymerization did not occur, and adhesive properties could not be grasped.
An object of the present invention is to provide an aqueous emulsion for an adhesive that is easy to produce, has high reproducibility, is excellent in normal adhesion to a polyolefin sheet, and further provides excellent heat-resistant creep properties, and a method for producing the same.

Under such circumstances, as a result of intensive studies by the present inventors, an aqueous emulsion in which a specific monomer is emulsion-polymerized under specific conditions in the presence of an aqueous polyurethane emulsion and a method for producing the same can solve such problems. As a result, the present invention has been completed.
The present invention relates to a method for producing an aqueous emulsion obtained by further emulsion polymerization of a monomer in the presence of a polyurethane aqueous emulsion, wherein at least ethylene, a vinyl ester and a polyfunctional monomer are used as the monomer, and the emulsion polymerization is a redox system. A method for producing an aqueous emulsion, characterized in that erythorbic acid and / or ascorbic acid is used together with a transition metal salt as a reducing agent for the redox catalyst, and
In an aqueous emulsion obtained by further emulsion polymerization of a monomer in the presence of a polyurethane aqueous emulsion, at least ethylene, a vinyl ester and a polyfunctional monomer are used as the monomer, and the emulsion polymerization is carried out with a redox catalyst. It is an aqueous emulsion obtained by using erythorbic acid and / or ascorbic acid as a reducing agent for a redox catalyst together with a transition metal salt.
Among them, it is preferable to use hydrogen peroxide as an oxidizing agent for a redox catalyst because coloring of the resulting aqueous emulsion tends to be reduced.

The aqueous emulsion obtained by the present invention has a normal adhesiveness equivalent to that of an adhesive obtained by separately producing and mixing an ethylene-vinyl acetate copolymer aqueous emulsion and a polyurethane aqueous emulsion, and is heat resistant. Creepability is remarkably excellent.
The production method of the present invention is easy to produce and has high reproducibility.

Hereinafter, the present invention will be described in detail.
The polyurethane aqueous emulsion used in the present invention is an aqueous emulsion in which a polyurethane obtained by reacting a polyisocyanate compound, a polyol compound, and, if necessary, another compound is dispersed in water. Examples of the reaction include methods such as an acetone method, a prepolymer mixing method, a ketimine method, and a hot melt dispersion method.

  The polyisocyanate compound is an organic polyisocyanate compound having two or more isocyanate groups in the molecule, which is used in the production of ordinary polyurethanes. For example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate, methylcyclohexyl-2,4-diisocyanate, methyl Cyclohexyl-2,6-diisocyanate, xylylene diisocyanate (XDI), 1,3-bis (isocyanate) methylcyclohexane, tetramethylxylylene diisocyanate, trans Aliphatic diisocyanates such as rhohexane-1,4-diisocyanate and lysine diisocyanate; 2,4-toluylene diisocyanate (TDI), 2,6-toluylene diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI) 1,5′-naphthene diisocyanate, tolidine diisocyanate, diphenylmethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4′-dibenzyl diisocyanate, aromatic diisocyanates such as 1,3-phenylene diisocyanate; Triphenylmethane triisocyanate, 1,6,11-undecane triisocyanate, 1,8-isocyanate-4,4-isocyanate methyloct 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, adducts of trimethylolpropane and toluylene diisocyanate, adducts of trimethylolpropane and 1,6-hexamethylene diisocyanate, etc. These may be used, and these may be used alone or in combination of two or more.

  Examples of the polyol compound include compounds having two or more hydroxyl groups in the molecule, which are used in the production of ordinary polyurethanes. For example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexane. Polyhydric alcohols such as diol, neopentyl glycol, trimethylolpropane, glycerin; polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol; adipic acid, sebacic acid, itaconic acid, maleic anhydride, terephthalic acid Dicarboxylic acids such as acid, isophthalic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, ethylene glycol, diethylene glycol, propylene Glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, 1,2-propanediol, 1,3-propanediol, 1,9-nonanediol, 3-methyl-1,5-pentane Polyester polyols obtained from polyol compounds such as diol, 1,3-propanediol, tripropylene glycol, trimethylolpropane and glycerin; polylactone-based polyester polyols such as polycaprolactone polyol and poly β-methyl-δ-valerolactone Polybutadiene polyol or hydrogenated product thereof, polycarbonate polyol, polythioether polyol, polyacrylate polyol and the like.

It is preferable to introduce a hydrophilic group into the molecule during the production of the polyurethane aqueous emulsion because the stability when the polyurethane aqueous emulsion is dispersed in water can be improved. Examples of the compound used for introducing a hydrophilic group include a nonionic hydrophilic group such as a structural unit derived from polyethylene glycol in the molecule, and a sulfonyl group, a carboxyl group, a hydroxyl group, a primary amino group (- NH ₂ ), secondary amino groups (═NH), and the like (hereinafter also referred to as hydrophilic group-containing compounds) having at least one active hydrogen having reactivity with an isocyanate group.

Examples of the hydrophilic group-containing compound include 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, 2,6-diaminobenzenesulfonic acid, and N- (2-aminoethyl) -2. Examples include sulfonic acid-containing compounds such as aminoethylsulfonic acid; carboxylic acid-containing compounds such as 2,2-dimethylollactic acid, 2,2-dimethylolpropionic acid, and 2,2-dimethylolvaleric acid. A hydrophilic group containing compound may be used independently and 2 or more types may be used together.
A polyurethane aqueous emulsion containing a hydrophilic group in the molecule obtained by using these hydrophilic group-containing compounds is called an ionomer structure, and has a surface-active ability in itself, so it tends to disperse in water, This is preferable because the aqueous emulsion obtained by further emulsion polymerization of a monomer to an aqueous polyurethane emulsion tends to improve the water resistance.

As the hydrophilic group, anionic groups such as a sulfonyl group and a carboxyl group are preferable, and a sulfonyl group is particularly preferable because it tends to further improve the water resistance of an aqueous emulsion obtained by emulsion polymerization of a monomer.
In general, the anionic group is preferably neutralized by a neutralizing agent. Examples of the neutralizing agent include tertiary amine compounds such as triethylamine and trietalamine; inorganic alkali compounds such as sodium hydroxide; ammonia and the like.

  A compound that is different from a hydrophilic group-containing compound for the purpose of chain extension or molecular weight adjustment as necessary when producing an aqueous polyurethane emulsion, and contains an active hydrogen capable of reacting with an isocyanate compound in the molecule May be used in combination. Examples of such compounds include polyvalent amine compounds such as ethylenediamine, 1,4-butanediamine, and 1,6-hexanediamine; tertiary amine-containing polyhydric alcohols such as triethanolamine, methanol, ethanol, and butanol. And monoalcohols.

As the polyurethane aqueous emulsion, a commercially available polyurethane aqueous emulsion may be used as it is.
Specifically, Hydran ECOS3000, ADS-120, ADS-110, Sanyo Chemical Industries Uprene UXA-3005, Sumika Bayer Urethane U-53, U-54, U-56, etc. manufactured by Dainippon Ink and Chemicals, Inc. It is done.

The method for producing an aqueous emulsion of the present invention is a method obtained by emulsion polymerization using a polyurethane aqueous emulsion as a seed and further using ethylene, vinyl ester and a polyfunctional monomer as monomers. Hereinafter, this process may be referred to as a seed polymerization process.
Examples of the vinyl ester used in the seed polymerization step include vinyl acetates such as vinyl acetate, vinyl butyrate, vinyl propionate, vinyl pivalate, vinyl laurate, vinyl isononanoate, and vinyl versatate. As the vinyl ester, two or more kinds of vinyl esters may be used. Of the vinyl esters, vinyl acetate is preferred.
The amount of vinyl ester used is about 60 to 95 parts by weight with respect to 100 parts by weight of the monomers used in the seed polymerization step.

The polyfunctional monomer is a monomer that can supply two or more ethylenic double bonds to a monomer such as ethylene or vinyl ester. Specific examples of the polyfunctional monomer include triallyl cyanurate, triallyl isocyanurate, diallyl phthalate and the like.
The amount of the polyfunctional monomer used is about 0.01 to 1 part by weight, preferably about 0.05 to 0.5 part by weight, with respect to 100 parts by weight of the vinyl ester used in the seed polymerization step. It is preferable because the heat resistant creep property tends to be improved.

Monomers used in the seed polymerization process are monomers different from ethylene, vinyl ester, and polyfunctional monomers, and can supply one ethylenic double bond to these monomers (hereinafter referred to as copolymerization). May be used), specifically, vinyl halides such as vinyl chloride and vinyl bromide; vinylidene halides such as vinylidene chloride; vinyl phosphonic acid and vinyl sulfonic acid And vinyl compounds such as salts thereof; aromatic vinyl such as styrene, α-methylstyrene and chlorostyrene; (meth) acrylic acid such as methacrylic acid and acrylic acid; methyl (meth) acrylate, butyl (meth) acrylate , (Meth) acrylic acid esters such as 2-ethylhexyl (meth) acrylate; maleic acid, maleic anhydride, succinic acid, ita Such as phosphate alpha, beta-unsaturated dicarboxylic acids; (meth) nitriles such as acrylonitrile; N- methylol acrylamide, acrylamide such as N- butoxymethyl acrylamide; allyl compounds such as sulfonic acid allyl and the like.
The amount of the copolymerizable monomer used is 20 parts by weight or less, preferably 10 parts by weight or less, based on 100 parts by weight of the total monomers used in the seed polymerization step.

The present invention uses a redox catalyst in the seed polymerization step, and uses erythorbic acid and / or ascorbic acid together with a transition metal salt as a reducing agent for the redox catalyst.
Examples of the transition metal salt include chlorides such as iron, copper, cobalt, titanium, nickel, chromium, zinc, manganese, vanadium, molybdenum, and cerium, and sulfates. Of these, ferrous chloride, ferrous sulfate, copper sulfate and the like are preferably used.
The transition metal salt is usually used in an amount of about 0.001 to 0.05 times by weight with respect to erythorbic acids and ascorbic acids which are reducing agents. If it is 0.001 times by weight or more, it is preferable because the reaction rate of emulsion polymerization tends to be improved, and if it is 0.05 times by weight or less, it is preferable because coloring of the produced aqueous emulsion tends to be reduced.

Examples of erythorbic acids and ascorbic acids that are reducing agents include alkali metal salts such as sodium salts and potassium salts in addition to erythorbic acid and ascorbic acid. Of these, sodium salts are preferable, and sodium erythorbate is particularly preferably used.
The reducing agent is usually used in an amount of about 0.02 to 1 part by weight with respect to 100 parts by weight of the vinyl ester. When the amount is 0.02 part by weight or more, the reaction rate of the emulsion polymerization tends to be improved, and when the amount is 1 part by weight or less, the generated aqueous emulsion suppresses discoloration or the performance of the obtained aqueous emulsion. For example, it is preferable because strength, water resistance and the like in the case of a film tend to be improved.

  Examples of the oxidizing agent for the redox catalyst include persulfates such as ammonium persulfate, potassium persulfate, and sodium persulfate; peroxides such as t-butyl peroxide and hydrogen peroxide. Among these, hydrogen peroxide is preferable because it is easy to handle and tends to suppress discoloration of the aqueous emulsion obtained.

An example of a method for producing an aqueous emulsion (seed polymerization step) is shown below.
Aqueous polyurethane emulsion, emulsifying dispersant, all or part of vinyl ester, transition metal salt, all or part of copolymerizable monomer, if necessary, all or part of polyfunctional monomer, acetic acid After putting the neutralizing agent in a pressure vessel and replacing with nitrogen, the temperature is raised to about 20 to 80 ° C., preferably about 40 to 70 ° C., and then the ethylene partial pressure is about 1 to 10 MPa, preferably 3 The ethylene is pressurized so as to be about ˜8 MPa.
Next, at about 20 to 80 ° C., an oxidizing agent such as hydrogen peroxide and erythorbic acids and / or ascorbic acids are gradually mixed in the pressure vessel. The oxidizing agent and erythorbic acid and / or ascorbic acid may be diluted with water or the like so as to be easily produced.
At the same time, while maintaining the temperature, gradually add the remaining vinyl ester, copolymerizable monomer and multifunctional monomer to the pressure vessel, and keep the temperature until the vinyl ester in the reaction solution in the pressure vessel is sufficiently reduced.・ Stir.
If the vinyl ester is not sufficiently reduced, a redox catalyst such as an oxidizing agent may be added.

  The amount (nonvolatile content) of the polyurethane aqueous emulsion used in the seed polymerization step is usually about 3 to 50 parts by weight with respect to 100 parts by weight of the nonvolatile content of the aqueous emulsion produced by seed polymerization. If it is 3 parts or more, the adhesive performance tends to be improved, and if it is 50 parts by weight or less, it is preferable because the emulsion polymerization rate of ethylene, vinyl ester, etc. tends to improve.

  Examples of the emulsifying dispersant used in the seed polymerization process include partially or completely saponified polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, starch, modified starch, oxidized starch, protective colloid such as sodium alginate, polyoxyethylene alkyl, etc. Nonionic surfactants such as ether, polyoxyethylene alkylphenol ether, polyoxyethylene / polyoxypropylene block copolymer, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, alkyl sulfate ester salt, alkylbenzene sulfonate, alkyl sulfosuccinate Acid salt, alkyl diphenyl ether disulfonate, polyoxyethylene alkyl sulfate, polyoxyethylene Anionic surfactants such as such as Rukirurin acid esters.

Here, the polyvinyl alcohol may be modified with a compound containing carboxylic acid, sulfonic acid, siloxane or the like.
As the polyvinyl alcohol, those having an average degree of polymerization of about 100 to 3000 and an average degree of saponification of about 80 to 98 mol% are preferable.
As the use amount of the emulsifying dispersant, the non-volatile content of the emulsifying dispersant is usually about 3 to 12 parts by weight, preferably 4 to 8 parts by weight with respect to 100 parts by weight of the monomers used in the seed polymerization step. Degree.

  The content of structural units derived from ethylene in the aqueous emulsion to be produced is usually about 5 to 70 parts by weight with respect to a total of 100 parts by weight of monomers used in the seed polymerization step. Among these, when the structural unit derived from ethylene is contained in an amount of 5 to 35 parts by weight, it is preferable because the adhesive force tends to be improved even at a low temperature of about 0 to 10 ° C.

When the ethylene partial pressure in the seed polymerization step is 1 MPa or more, the content of structural units derived from ethylene in the aqueous emulsion to be produced tends to improve and the reaction time tends to improve. On the other hand, the pressure is preferably 10 MPa or less from the viewpoint of pressure resistance of the pressure vessel.
In order to increase the structural unit derived from ethylene relative to the sum of the structures derived from all monomers used in the seed polymerization step, the vinyl ester content of the monomer in the reaction solution in the pressure vessel is kept low. What is necessary is just to superpose | polymerize, and what is necessary is just to adjust suitably the quantity of the vinyl ester added from the beginning or later.

The produced aqueous emulsion usually has a nonvolatile content of about 40 to 75% by weight, and can be diluted with water as necessary.
The water-based emulsion can be used as it is or after adjusting the water content and adding the compounding agent described below to apply it to adhesives such as woodworking adhesives, paper processing adhesives, plastics adhesives, and the surface of substrates. It can be used as a paint.

Examples of compounding agents that can be incorporated into the adhesive include thermosetting resins such as urea resins, melamine resins, and phenol resins, fillers such as clay, kaolin, talc, and calcium carbonate, antiseptics, rust inhibitors, and antifoaming agents. Additives such as agents, foaming agents, thickeners such as polyacrylic acid and polyether, viscosity modifiers, flame retardants, pigments such as titanium oxide, and plasticizers such as dibasic acid esters.
It is recommended that the filler is used for improving flame retardancy and coating properties at the time of adhesion. The amount of the filler used is usually 1 to 100 parts by weight of the nonvolatile content of the aqueous emulsion to be produced. About 500 parts by weight, preferably about 5 to 200 parts by weight.

  When an aqueous emulsion is used as an adhesive, it may be used as a one-pack type adhesive containing an aqueous emulsion as an active ingredient. However, if adhesive performance such as heat creep resistance and water resistance is required, a curing agent may be used. Can be used in combination. As the curing agent, an isocyanate-based curing agent is effective, and there are MDI, TDI, HDI, XDI and oligomers and polymers thereof. The blending amount of the curing agent is 0.1 to 20 parts by weight with respect to 100 parts by weight of the aqueous emulsion. Preferably it is 1-10 weight part. Examples of commercially available products include Sumidur 44V20 and Sumidur N3300 made by Sumika Bayer Urethane.

Examples of the base material to be applied to the adhesive of the present invention include wood-based materials such as wood, plywood, MDF, particle board, and fiber board; paper-based materials such as wallpaper and wrapping paper: cotton cloth, linen, rayon, etc. Examples thereof include a material that absorbs water, such as a cellulosic material or a porous material.
Furthermore, if a part of the adhesive of the present invention is attached to a material that absorbs water, the other part is a plastic material such as polyolefin, such as polyethylene, polypropylene, polystyrene, polyester, polyether, polyvinyl chloride, etc. Ceramic materials such as glass and ceramics may be used as the adherend.
In particular, a laminate formed by adhering water-absorbing material and polyolefin through an adhesive is obtained through an adhesive composition comprising an ethylene-vinyl acetate copolymer aqueous emulsion and a polyurethane aqueous emulsion. The laminate has a normal adhesiveness that is about the same as that of the laminate, and the heat-resistant creep resistance is remarkably excellent.

  Hereinafter, the present invention will be described in more detail with reference to examples. Parts and% mean weight basis unless otherwise specified. The nonvolatile content was measured by a measuring method according to JIS K-6828. The viscosity is a value measured with a Brookfield viscometer (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C.

Example 1
<Production example of aqueous emulsion (B1)>
In a pressure-resistant container, 160 parts of water in advance, 160 parts of vinyl acetate, polyvinyl alcohol “Poval 217” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 1700) 7 parts, “Poval 205” ( ) Kuraray Co., Ltd., Saponification degree 88 mol%, average polymerization degree 500) 2 parts, polyurethane aqueous emulsion (A1, anion type urethane emulsion "Hydran ECOS-3000", Dainippon Ink & Chemicals, Inc., nonvolatile content 40% ) A solution in which 40 parts, ferrous sulfate heptahydrate 0.005 part and acetic acid 0.4 part were dissolved was introduced. Next, the inside of the pressure vessel was replaced with nitrogen gas, and the inside of the vessel was heated to 60 ° C. and then pressurized to 4.6 MPa with ethylene. Next, 0.5 part of a 30% hydrogen peroxide-containing aqueous solution and 0.6 part of sodium erythorbate were diluted with water, and dropping was started. Subsequently, after confirming that the liquid temperature in the pressure vessel had risen, a solution prepared by dissolving 0.17 parts of triallyl isocyanurate in 10 parts of vinyl acetate was added over 3 hours. During polymerization, the temperature in the reaction vessel is kept at 60 ° C. by controlling the temperature of the jacket. Further, an aqueous solution of hydrogen peroxide is added and stirred until the vinyl acetate concentration in the reaction solution becomes 1% or less. The ethylene gas of the reaction was removed to obtain an aqueous emulsion (B1).
The resin composition of the obtained water-based emulsion (B1) is composed of 100 parts of a structural unit derived from vinyl acetate, 22 parts of a structural unit derived from ethylene, 0.1 part of a structural unit derived from triallyl isocyanurate, an aqueous polyurethane emulsion ( The resin content (nonvolatile content) derived from A) was 9 parts, and the resin content derived from polyvinyl alcohol (nonvolatile content) was 5.3 parts. The aqueous emulsion (B1) had a nonvolatile content of 52.5% and a viscosity of 1200 mPa · s.

<Production Example 1 of Adhesive and Laminate>
Incubator DBE (mixture of dibasic acid ester (dimethyl succinate, dimethyl adipate, dimethyl glutamate)), which is a plasticizer, is added to 110 parts of the aqueous emulsion (B1), and is used as a thickener. (SN thickener A-812, San Nopco Co., Ltd. registered trademark, urethane-modified polyether, active ingredient 40%) was diluted 2 times and used as an adhesive. Using this adhesive, an adhesion test was performed as follows.

<Evaluation of adhesive strength>
After applying an aqueous emulsion to JAS1 water-resistant plywood to 110 g / m ² , Dai Nippon Printing non-vinyl chloride sheet WS-201E (polyolefin sheet thickness 0.16 mm) was pasted and degassed with a hand roller. After standing for 1 day while pressing with 50 kg weight / 900 cm ² , the pressing was released and the laminate was further dried for 6 days to obtain a laminate.
The normal peel strength was measured at a peel rate of 200 mm / min (Shimadzu Autograph). Further, the heat-resistant creep was adjusted to a temperature of 80 ° C., and then peeled at a peel angle of 90 ° and a load of 500 g / 25 mm, and the peel length at each time was measured. The results are summarized in Table 1.

(Example 2)
<Production example of aqueous emulsion (B2)>
Except for using 32 parts of an aqueous emulsion (A2, ADS-120 (50%) manufactured by Dainippon Ink and Chemicals) instead of the polyurethane aqueous emulsion of Example 1 (A1, 40 parts of Hydran ECOS-3000 manufactured by Dainippon Ink and Chemicals). It carried out similarly.
The resin composition of the obtained aqueous emulsion (B2) is composed of 100 parts of a structural unit derived from vinyl acetate, 22 parts of a structural unit derived from ethylene, 0.1 part of a structural unit derived from triallyl isocyanurate, an aqueous polyurethane emulsion ( The resin content (nonvolatile content) derived from A) was 9 parts, and the resin content derived from polyvinyl alcohol (nonvolatile content) was 5.3 parts. The non-volatile content of the aqueous emulsion (B2) was 53.1%, and the viscosity was 7570 mPa · s.
Example of blending 5.3 parts of DBE manufactured by INVISTER JAPAN into 110 parts of this aqueous emulsion (B2) and 0.5 part of a two-fold dilution of San Nopco thickener A-812 The adhesion test was carried out in the same manner as in 1. The results are summarized in Table 1.

(Comparative Example 1)
<Production example of aqueous emulsion (C)>
The same procedure as in Example 1 was performed except that “0.5 part of sodium persulfate” was used instead of “0.5 part of 30% hydrogen peroxide-containing aqueous solution and 0.6 part of sodium erythorbate” in Example 1.
Vinyl acetate in the pressure vessel did not decrease, and emulsion polymerization did not proceed.

(Comparative Example 2)
<Production Example of Ethylene-Vinyl Acetate-Polyfunctional Monomer Copolymer Aqueous Emulsion (D)>
In a pressure vessel, 160 parts of water in advance 180 parts of vinyl acetate, polyvinyl alcohol “Poval 217” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 1700) 8 parts, “Poval 205” ) Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 500) A solution in which 2.3 parts, 0.005 part of ferrous sulfate heptahydrate and 0.4 part of acetic acid were dissolved was introduced. Next, the inside of the pressure vessel was replaced with nitrogen gas, and the inside of the vessel was heated to 60 ° C. and then pressurized to 4.6 MPa with ethylene. Next, each of 0.33 part of a 30% hydrogen peroxide-containing aqueous solution and 0.6 part of sodium erythorbate was diluted with water, and dropping was started. Subsequently, after confirming that the liquid temperature in the pressure vessel had risen, a solution prepared by dissolving 0.19 part of triallyl isocyanurate in 10 parts of vinyl acetate was added over 3 hours. During polymerization, the temperature in the reaction vessel is kept at 60 ° C. by controlling the temperature of the jacket. Further, an aqueous solution of hydrogen peroxide is added and stirred until the vinyl acetate concentration in the reaction solution becomes 1% or less. The ethylene gas of the reaction was removed to obtain an ethylene-vinyl acetate-polyfunctional monomer copolymer aqueous emulsion (D).
The resin composition of the obtained aqueous emulsion (D) is derived from polyvinyl alcohol, with 100 parts of structural unit derived from vinyl acetate, 22 parts of structural unit derived from ethylene, 0.1 part of structural unit derived from triallyl isocyanurate, The structural unit was 5.4 parts. The non-volatile content of the aqueous emulsion (D) was 55.0%, and the viscosity was 3000 mPa · s.

<Example of production of adhesive and laminate>
An adhesive was prepared by blending 100 parts of the aqueous emulsion (D) with 4 parts of DBE 4.8 parts manufactured by Invistor Japan and Sannopco thickener A-812 diluted 2-fold. Using this adhesive, an adhesion test was conducted in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 3)
<Example of production of adhesive composition comprising aqueous emulsion (D) and aqueous polyurethane emulsion>
100 parts of the aqueous emulsion (D) obtained in Comparative Example 2, 10.6 parts of an anionic urethane emulsion “Hydran ECOS-3000” (Dainippon Ink Chemical Co., Ltd., nonvolatile content 40%), manufactured by Invister Japan After blending 5.3 parts of DBE and adjusting to pH 8-9 with 0.2 part of 25% aqueous ammonia, 4 parts of 2 times diluted San Nopco thickener A-812 were blended to make an adhesive. . Using this adhesive, an adhesion test was conducted in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 4)
<Production Example of Adhesive Composition Composed of Ethylene-Vinyl Acetate-Polyfunctional Monomer Copolymer Aqueous Emulsion (D) and Aqueous Polyurethane Emulsion>
100 parts of the aqueous emulsion (D) obtained in Comparative Example 2, 8.5 parts of an anionic urethane emulsion “Hydran ADS-120” (manufactured by Dainippon Ink & Chemicals, Inc., nonvolatile content 50%), manufactured by Invister Japan After blending 5.3 parts of DBE and adjusting to pH 8-9 with 0.2 part of 25% aqueous ammonia, 4 parts of 2 times diluted San Nopco thickener A-812 were blended to make an adhesive. . Using this adhesive, an adhesion test was conducted in the same manner as in Example 1. The results are summarized in Table 1.

(Comparative Example 5)
<Production example of aqueous emulsion (E)>
In a pressure-resistant container, 170 parts of water in advance, 170 parts of vinyl acetate, polyvinyl alcohol “Poval 217” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average degree of polymerization 1700), 2 parts “Poval 205” ) Kuraray Co., Ltd., Saponification degree 88 mol%, Average polymerization degree 500) 6 parts, Polyurethane aqueous emulsion (A) (Polyester anionic urethane emulsion "Hydran ECOS-3000", Dainippon Ink & Chemicals, non-volatile 40%), a solution in which 0.005 part of ferrous sulfate heptahydrate and 0.4 part of acetic acid were dissolved was introduced. Next, the inside of the pressure vessel was replaced with nitrogen gas, and the inside of the vessel was heated to 60 ° C. and then pressurized to 4.6 MPa with ethylene. Next, 0.5 part of a 30% hydrogen peroxide-containing aqueous solution and 0.6 part of sodium erythorbate were diluted with water, and dropping was started. During polymerization, the temperature in the reaction vessel is kept at 60 ° C. by controlling the temperature of the jacket. Further, an aqueous solution of hydrogen peroxide is added and stirred until the vinyl acetate concentration in the reaction solution becomes 1% or less. The ethylene gas of the reaction was removed to obtain an aqueous emulsion (E).
The resin composition of the obtained aqueous emulsion (E) is composed of 100 parts of the structural unit derived from vinyl acetate, 22 parts of the structural unit derived from ethylene, 9 parts of the resin (nonvolatile content) of the aqueous emulsion (A), polyvinyl The alcohol resin content (nonvolatile content) was 4.7 parts.
The non-volatile content of the aqueous emulsion (E) was 52.9%, and the viscosity was 1890 mPa · s.
In the same manner as in Example 1 except that 5.3 parts of DBE manufactured by Invista Japan was blended with 110 parts of this emulsion (E), and 6 parts blended with Sannopco thickener A-812 diluted twice. An adhesion test was conducted. The results are summarized in Table 1.

(Comparative Example 6)
<Example of production of ethylene-vinyl acetate copolymer aqueous emulsion (F)>
In a pressure-resistant container, 160 parts of water in advance, 190 parts of vinyl acetate, polyvinyl alcohol “Poval 217” (manufactured by Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 1700) 2.3 parts, “Poval 205” ) Kuraray Co., Ltd., saponification degree 88 mol%, average polymerization degree 500) 7 parts, ferrous sulfate heptahydrate 0.005 part and acetic acid 0.4 part were dissolved. Next, the inside of the pressure vessel was replaced with nitrogen gas, and the inside of the vessel was heated to 60 ° C. and then pressurized to 4.6 MPa with ethylene. Next, each of 0.33 part of a 30% hydrogen peroxide-containing aqueous solution and 0.6 part of sodium erythorbate was diluted with water, and dropping was started. During polymerization, the temperature in the reaction vessel is kept at 60 ° C. by controlling the temperature of the jacket. Further, an aqueous solution of hydrogen peroxide is added and stirred until the vinyl acetate concentration in the reaction solution becomes 1% or less. The ethylene gas of the reaction was removed to obtain an ethylene-vinyl acetate copolymer aqueous emulsion (F).
The resin composition of the obtained water-based emulsion (F) was 22 parts of structural units derived from ethylene and 4.9 parts of polyvinyl alcohol resin (nonvolatile content) with respect to 100 parts of structural units derived from vinyl acetate. The non-volatile content of the aqueous emulsion (F) was 55.0%, and the viscosity was 1200 mPa · s.

<Example of production of adhesive composition comprising aqueous emulsion (F) and polyurethane aqueous emulsion>
100 parts of an aqueous emulsion (F), 10.6 parts of an anionic urethane emulsion “Hydran ECOS-3000” (Dainippon Ink Chemical Co., Ltd., nonvolatile content 40%), and 5.3 parts of DBE made by Invisstar Japan After adjusting the pH to 8-9 with 0.2 part of 25% aqueous ammonia, 6 parts of a 2-fold diluted thickener A-812 made by San Nopco was blended to prepare an adhesive. Using this adhesive, an adhesion test was conducted in the same manner as in Example 1. The results are summarized in Table 1.

ECOS3000: Hydran ECOS3000 manufactured by Dainippon Ink and Chemicals, Inc.
ADS-120: Dainippon Ink & Chemicals Hydran ADS-120
DBE: DBE made by Invisstar Japan
2-fold dilution A-812: Sannopco thickener A-812 is diluted 2-fold

As is clear from Table 1, although it is difficult to reproduce Patent Document 2 (Comparative Example 1), the production methods of the present invention (Examples 1 and 2) can be easily produced. Further, the adhesive of the present invention includes an adhesive containing only an aqueous emulsion containing ethylene / vinyl acetate / polyfunctional monomer copolymer (Comparative Example 2), the aqueous copolymer-containing emulsion and an aqueous polyurethane emulsion. Compared with adhesives containing the same (Comparative Examples 3, 4 and 6 according to Patent Document 1), the normal strength is almost the same, but the heat resistant creep resistance is excellent even for a long time.
Furthermore, when a polyfunctional monomer is not used for seed polymerization (Comparative Example 5), the heat resistant creep resistance is significantly reduced.

  According to the present invention, for woodworking, for paper processing, for wallpaper, for packaging, for (secondary) plywood, for construction sites, for construction factories, for laminating, for textiles, for home use, for civil engineering, for binding, etc. It can be used for two-pack type paints that use a one-pack type adhesive and a curing agent in combination, and paints.

Claims (6)

  In a method for producing an aqueous emulsion obtained by further emulsion polymerization of a monomer in the presence of an aqueous polyurethane emulsion, at least ethylene, vinyl ester and a polyfunctional monomer are used as the monomer, and the emulsion polymerization is carried out using a redox catalyst. And erythorbic acid and / or ascorbic acid as a reducing agent for the redox catalyst together with a transition metal salt.   2. The production method according to claim 1, wherein hydrogen peroxide is used as an oxidizing agent for the redox catalyst.   An adhesive comprising an aqueous emulsion obtained by the production method according to claim 1 and a compounding agent.   A laminate comprising the adhesive according to claim 3 and a substrate capable of absorbing water.   The laminate according to claim 4, further comprising a polyolefin on the adhesive layer side.   In an aqueous emulsion obtained by further emulsion polymerization of a monomer in the presence of a polyurethane aqueous emulsion, at least ethylene, a vinyl ester and a polyfunctional monomer are used as the monomer, and the emulsion polymerization is carried out with a redox catalyst. An aqueous emulsion obtained by using erythorbic acids and / or ascorbic acids together with a transition metal salt as a reducing agent for a redox catalyst.