JP2005344053A - Aqueous emulsion for adhesive and adhesive composition using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous emulsion which is suitably used as an adhesive together with an isocyanate-based compound and exhibits excellent boiling-resistant adhesiveness and good storage stability after compounded with a pigment without deteriorating the pot life of the adhesive. <P>SOLUTION: This aqueous emulsion (1) obtained by emulsion-polymerizing a monomer composition comprising at least one monomer selected from aromatic vinyl monomers and (meth)acrylate monomers, a hydroxyl group-containing vinyl monomer, and an unsaturated carboxylic acid monomer in the presence of a reactive surfactant is characterized in that the particle diameter of the aqueous emulsion (1) is 200 to 600 nm. <P>COPYRIGHT: (C)2006,JPO&amp;NCIPI

Description

  The present invention relates to an aqueous emulsion for adhesives which has good storage stability when blended with a pigment in an aqueous emulsion, and is excellent in normal state adhesiveness and boiling resistance, for example, suitable as an adhesive for wood. is there. More specifically, the present invention relates to an aqueous emulsion which is suitably used as an adhesive in combination with an isocyanate compound and exhibits particularly excellent boiling resistance without impairing the pot life of the adhesive.

An adhesive containing an isocyanate compound in an aqueous emulsion is well known as an aqueous polymer-isocyanate adhesive, and extremely high adhesive strength can be obtained simply by pressing in a short time at room temperature or under heating. . Unlike conventional amino-urea adhesives, there is no generation of formaldehyde, which has attracted attention in recent years due to indoor environmental problems.
This water-based polymer-isocyanate adhesive has not only normal adhesive performance but also secondary performance such as boiling resistance, and exhibits excellent performance particularly for wood bonding. For example, it is widely used for laminated timber and plywood. However, due to recent diversification of wood species, the conventional water-based polymer-isocyanate-based adhesives have no problem with normal adhesiveness, but particularly have low boiling resistance. In addition, the environment in which the laminated wood is used may be placed in a more severe environment, such as being left at a high temperature and high humidity for a long period of time compared to the past. In such a situation, further improvement in the boiling resistance of the aqueous polymer-isocyanate adhesive is required in the market.

Furthermore, various kinds of organic and inorganic pigments are blended in the water-based polymer-isocyanate adhesive for diversified required performance. This pigment is generally blended in an aqueous emulsion, but recently, storage stability in which the viscosity of the blend changes with time has become a problem.
For the purpose of improving adhesiveness, the curing reactivity of the isocyanate compound is inevitably increased, and this is not preferable because it leads to a decrease in workability associated with a shortened pot life at the pasting site.
Moreover, in order to improve the storage stability after blending the pigment, a large amount of pigment dispersant may be added, but the pot life after blending the isocyanate compound becomes poor.
Therefore, the improvement of the adhesiveness mentioned above, the storage stability after a pigment mixing | blending, and the improvement of the extension of a pot life are greatly desired.

For this problem, for example, Patent Document 1 discloses that at least one selected from an aromatic vinyl monomer, a (meth) acrylic acid ester monomer, a hydroxy group-containing vinyl monomer, and an unsaturated carboxylic acid. It is disclosed that an emulsion having a particle diameter of 100 to 400 nm obtained by emulsion polymerization of an acid monomer using a surfactant is preferable. However, although this emulsion has good initial adhesion and boiling resistance, Patent Document 1 does not have any description or suggestion regarding improvement in storage stability after blending pigments and improvement in pot life after blending isocyanate compounds. And the emulsion was not sufficient in those respects.
Further, for example, Patent Document 2 discloses that one or more selected from an aromatic vinyl monomer and a (meth) acrylic acid ester monomer and a hydroxy group-containing vinyl monomer have a specific structure and It is disclosed that an aqueous emulsion obtained by emulsion polymerization in the presence of a compound having a radical polymerizable double bond is preferred. However, although this emulsion has good initial adhesion, resistance to boiling, and pot life, Patent Document 2 does not have any description or suggestion regarding improvement of storage stability after blending the pigment, and the emulsion is in that respect. It was not enough.

JP 2002-129121 A JP 2003-193010 A

  The present invention is suitably used as an adhesive in combination with an isocyanate compound, (1) without impairing the pot life of the adhesive, (2) good storage stability after pigment incorporation, (3) It is an object of the present invention to provide an aqueous emulsion exhibiting particularly excellent normal adhesion and boiling resistance.

In order to solve the problems (1) to (3) at the same time, the present inventor has found an aqueous emulsion obtained by emulsion polymerization of a specific monomer composition using a reactive surfactant. The present invention has been made.
That is, the present invention
[1] Monomer containing at least one monomer selected from aromatic vinyl monomers and (meth) acrylate monomers, hydroxyl group-containing vinyl monomers, and unsaturated carboxylic acid monomers An aqueous emulsion (1) obtained by emulsion polymerization of a body composition using a reactive surfactant, wherein the average particle size of the emulsion (1) is 200 to 600 nm Aqueous emulsion for adhesives.
[2] The aqueous emulsion for adhesives according to claim 1, wherein the hydroxyl group-containing vinyl monomer is 0.5 to 5% by mass in the total monomer composition.
[3] An adhesive composition comprising the aqueous emulsion (1) according to [1] or [2] and an isocyanate compound (2),
It is.

  The adhesive composition containing the aqueous emulsion for adhesives (1) and the isocyanate compound (2) of the present invention has good state adhesiveness, boiling resistance, and good pigment composition without impairing pot life. It has the effect of developing later storage stability.

The present invention will be specifically described below.
The aqueous emulsion (1) of the present invention is obtained by emulsion polymerization. There is no restriction | limiting in particular regarding the method of emulsion polymerization, A conventionally well-known method can be used. That is, other additives such as a monomer composition, a radical polymerization initiator, a reactive surfactant, a non-reactive surfactant if necessary, and a chain transfer agent used as necessary in an aqueous medium This is a method in which a monomer composition is polymerized in a dispersion system in which components and the like are basic composition components. In the polymerization, the composition of the supplied monomer composition is made constant throughout the entire polymerization process, and the morphological composition change of the latex particles produced is changed by changing the polymerization process sequentially or continuously. Various methods can be used as desired.

Examples of the aromatic vinyl monomer used in the aqueous emulsion (1) of the present invention include styrene, vinyl toluene, α-methyl styrene, β-methyl styrene and the like. Styrene is preferred.
Examples of the (meth) acrylic acid ester monomer used in the aqueous emulsion (1) of the present invention include methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, butyl acrylate, isobutyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2 -Ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, phenyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl acrylate, butyl methacrylate, isobutyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, phenyl methacrylate Over doors and the like. Preferred are butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate.

  Examples of the hydroxyl group-containing vinyl monomer used in the aqueous emulsion (1) of the present invention include hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, polyethylene glycol acrylate, polyethylene glycol methacrylate and the like. . Preferred are hydroxyethyl acrylate and hydroxyethyl methacrylate.

Examples of the unsaturated carboxylic acid monomer used in the aqueous emulsion (1) of the present invention include acrylic acid, methacrylic acid, maleic acid or monoester thereof, fumaric acid or monoester thereof, itaconic acid or monoester thereof, and the like. Is mentioned. Preferred are unsaturated carboxylic acid monomers of acrylic acid, methacrylic acid and itaconic acid, and more preferred are acrylic acid and methacrylic acid.
In addition to the above monomers, other monomer components can be used to improve various qualities and physical properties required for the aqueous emulsion (1) of the present invention. Examples of monomers other than those described above include (a) amide group-containing vinyl monomers, (b) cyano group-containing vinyl monomers, (c) crosslinkable monomers, and (d) other ethylenically unsaturated monomers. Examples include a polymer.

(A) Examples of the amide group-containing vinyl monomer include acrylamide, methacrylamide, N, N-methylenebisacrylamide, diacetone acrylamide, diacetone methacrylamide, maleic acid amide, maleimide and the like.
(B) Examples of the cyano group-containing vinyl monomer include acrylonitrile and methacrylonitrile.
(C) A monomer having two or more radical polymerizable double bonds as a crosslinkable monomer, or a monomer having a functional group that gives a self-crosslinking structure after polymerization during polymerization The body is mentioned.
Examples of the monomer having two or more radical polymerizable double bonds include aromatic compounds having two or more radical polymerizable double bonds such as divinylbenzene, and polyoxyethylene diacrylate. , Polyoxyalkylene di (meth) acrylates such as polyoxyethylene dimethacrylate, polyoxypropylene diacrylate, polyoxypropylene dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, butanediol diacrylate, butanediol dimethacrylate Triol tri (meth) acrylates such as diol di (meth) acrylate such as alkyl diol di (meth) acrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate , And pentaerythritol tetraacrylate, an ester compound of two or more (meth) acrylic acid such as tetraol (meth) acrylates such as pentaerythritol tetramethacrylate and the like.

Examples of monomers having a functional group that gives a cross-linked structure after polymerization include, for example, epoxy group-containing vinyl monomers, methylol group-containing monomers, alkoxymethyl group-containing monomers, hydrolyzable silyls. Examples thereof include vinyl monomers having a group.
Other monomers (d) can also be used. For example, various vinyl monomers having functional groups such as amino group, sulfonic acid group, and phosphoric acid group, as well as vinyl acetate, vinyl propionate, vinyl versatic acid, vinyl pyrrolidone, methyl vinyl ketone, butadiene, ethylene, propylene Vinyl chloride, vinylidene chloride and the like can be used as desired.

The aromatic vinyl-type monomer used for the aqueous emulsion (1) of this invention is 5-80 mass% in all the monomers. When the aromatic vinyl monomer is 5% by mass or more, the boiling resistance is good, and when it is 80% by mass or less, the normal adhesiveness is good. Preferably, it is 10-60 mass%.
The (meth) acrylic acid ester monomer used in the aqueous emulsion (1) of the present invention is 5 to 80% by mass in all monomers. When the (meth) acrylic acid ester monomer is 5% by mass or more, the boiling resistance is good, and when it is 80% by mass or less, the normal state adhesiveness is good. Preferably, it is 10-60 mass%.
The hydroxyl group-containing vinyl monomer used in the aqueous emulsion (1) of the present invention is 0.5 to 5% by mass in the total monomers. When 0.5% by mass or more, normal adhesiveness is good, pot life and boiling resistance are also good, and when 5% by mass or less, pot life is good, normal adhesiveness and boiling resistance. Is also good. Preferably it is 1-4 mass%.
The unsaturated carboxylic acid monomer used in the aqueous emulsion (1) of the present invention is 0.1 to 4% by mass in the total monomers. When the content is 0.1% by mass or more, the storage stability after blending the pigment is good, and when the content is 4% by mass or less, the boiling resistance is good. Preferably it is 0.5-3 mass%.

The glass transition temperature Tg of the aqueous emulsion (1) of the present invention is preferably -40 ° C to 40 ° C. Boiling resistance is good at -40 ° C or higher, and normal state adhesiveness is good at 40 ° C or lower. Preferably it is -30 degreeC-30 degreeC.
The glass transition temperature of the polymer mentioned here can be defined by the following equation from the glass transition temperature of the monomer homopolymer and the copolymerization ratio of the monomer.
1 / Tg = W1 / Tg1 + W2 / Tg2 + ...
Tg: Glass transition temperature (° K) of a polymer comprising monomers 1, 2...
W1, W2 ···: Monomer 1, monomer 2, ··· mass fraction W1 + W2 + ··· = 1
Tg1, Tg2 ···: Glass transition temperature (° K) of homopolymer of monomer 1, monomer 2, ...
The Tg (° K) of the monomer homopolymer used in the calculation is described in, for example, the polymer handbook (Jhon Willy & Sons). The numerical value used in this application is illustrated. The value in parentheses indicates the Tg of the homopolymer. Polystyrene (373 ° K), polymethyl methacrylate (378 ° K), polybutyl acrylate (219 ° K), poly 2-ethylhexyl acrylate (205 ° K), polyacrylic acid (379 ° K), polymethacrylic acid (403 ° K), polyacrylonitrile (373 ° K), poly-2-hydroxyethyl acrylate (258 ° K), and poly-2-hydroxyethyl methacrylate (328 ° K).

The reactive surfactant used in the aqueous emulsion (1) of the present invention has at least one hydrophilic group and one or more lipophilic group in one molecule, and has an ethylenic double group in its structure. A bond has been introduced.
Among the reactive surfactants, the anionic surfactant is, for example, an ethylenically unsaturated monomer having a sulfonic acid group, a sulfonate group or a sulfate ester group and a salt thereof, a sulfonic acid group, or an ammonium thereof. A compound having a group (ammonium sulfonate group or alkali metal sulfonate group) which is a salt or an alkali metal salt is preferable. For example, alkylallylsulfosuccinate (for example, Sanyo Kasei Co., Ltd., Eleminol (trademark) JS-2, JS-5, for example, Laomul (trademark) S-120, S-180A, S-180 manufactured by Kao Corporation), etc. ), For example, polyoxyethylene alkylpropenyl phenyl ether sulfate ester salt (for example, Aqualon (trademark) HS-10 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), for example, α- [1-[(allyloxy) methyl] -2 -(Nonylphenoxy) ethyl] -ω-polyoxyethylene sulfate ester salt (for example, Adeka Soap (trademark) SE-1025N manufactured by Asahi Denka Kogyo Co., Ltd.), for example, ammonium α-sulfonato-ω-1- (Allyloxymethyl) alkyloxypolyoxyethylene (for example, Aqualon KH manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 10), for example, ammonium salts of α-sulfo-ω- (1- (alkoxy) methyl-2- (2-propenyloxy) ethoxy) -poly (oxy-1,2-ethanediyl) (for example, Asahi Denka) (Adekaria soap SR-10), styrene sulfonate, etc. are mentioned.

Examples of the reactive surfactant and nonionic surfactant include α- [1-[(allyloxy) methyl] -2- (nonylphenoxy) ethyl] -ω-hydroxypolyoxyethylene (for example, Asahi Denka Kogyo ( Adekaria soap NE-20, NE-30, NE-40, etc.), for example, polyoxyethylene alkylpropenyl phenyl ether (for example, Aqualon RN-10, RN-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) RN-30, RN-50, etc.).
The reactive surfactant used in the present invention comprises 0.1 to 5 parts by weight of anionic surfactant and 0.1 to 5 parts by weight of nonionic surfactant with respect to 100 parts by weight of the total monomer composition. Can be used. When the anionic surfactant is 0.1 part by mass or more, the storage stability after blending the pigment is good, and when it is 5 parts by mass or less, boiling resistance is good. Further, the storage stability after blending the pigment is good when the nonionic surfactant is 0.1 part by mass or more, and the boiling resistance is good when it is 5 parts by mass or less.
Anionic reactive surfactants and nonionic reactive surfactants may be used alone or in combination. The reactive surfactant may be added before polymerization, during polymerization, or after polymerization.

In order to improve various qualities and physical properties required for the aqueous emulsion (1) of the present invention, a non-reactive surfactant can be used in combination. Non-reactive surfactants include, for example, aliphatic soaps, rosin acid soaps, alkyl sulfonates, dialkylaryl sulfonates, alkylsulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl aryl sulfates, etc. Nonionic surfactants such as anionic surfactants, polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene oxypropylene block copolymers and the like can be mentioned.
The method of using the non-reactive surfactant is not particularly limited, and for example, it may be used at the time of emulsion polymerization, or a necessary amount may be added after the emulsion polymerization.

The polymerization initiator is one that initiates the addition polymerization of the monomer by radical decomposition with heat or a reducing substance, and both inorganic and organic initiators can be used. As such, water-soluble and oil-soluble polymerization initiators can be used. Examples of water-soluble polymerization initiators include peroxodisulfates, peroxides, water-soluble azobis compounds, peroxide-reducing agent redox systems, and the like. Peroxodisulfates include, for example, potassium peroxodisulfate ( KPS), sodium peroxodisulfate (NPS), ammonium peroxodisulfate (APS) and the like. Examples of peroxides include hydrogen peroxide, t-butyl hydroperoxide, t-butyl peroxymaleic acid, and succinic acid peroxide. Examples of water-soluble azobis compounds include 2,2-azobis (N-hydroxyethylisobutyramide), 2,2-azobis (2-amidinopropane) hydrogen chloride, 4,4- Azobis (4-cyanopentanoic acid) and the like. Examples of the dox system include sodium sulfooxylate formaldehyde, sodium bisulfite, sodium thiosulfate, sodium hydroxymethanesulfinate, L-ascorbic acid, and salts thereof, cuprous salts and ferrous salts. A reducing agent such as can also be used in combination with the polymerization initiator.
The polymerization temperature in this emulsion polymerization is usually selected in the range of 60 to 100 ° C., but the polymerization may be carried out at a lower temperature by the redox polymerization method or the like. For example, in the two-stage polymerization, the polymerization temperature in the first stage and the polymerization temperature in the second stage may be the same or different.

The average particle size of the aqueous emulsion (1) of the present invention is controlled to 200 to 600 nm. When the average particle size is 200 nm or more, the pot life is good, and the normal state adhesiveness and boiling resistance are also good. When the average particle size is 600 nm or less, the pot life, normal state adhesiveness and boiling resistance are good. The average particle size is preferably 300 to 500 nm.
The particle diameter control method of the aqueous emulsion (1) of the present invention is not particularly limited. For example, it can be adjusted according to the use ratio of seed particles and surfactants. In general, the higher the use ratio, the smaller the average particle diameter of the emulsion produced, and vice versa. is there. The seed particles may be polymerized in the same reaction vessel prior to the emulsion polymerization of the present invention, or seed particles polymerized in different reaction vessels may be used.

The isocyanate compound (2) used in the present invention only needs to contain two or more isocyanate groups in one molecule. For example, tolylene diisocyanate, hydrogenated tolylene diisocyanate, triphenylmethane triisocyanate, methylene bisdiphenyl. Examples thereof include diisocyanate, polymethylene phenyl polyisocyanate, hydrogenated methylene bisdiphenyl diisocyanate, xylene diisocyanate, hexamethylene diisocyanate and the like. Further, it may be an isocyanate polymer obtained by previously reacting water, a polyhydric alcohol, a hydroxyl group-containing polyether, or a hydroxyl group-containing polyester with an excess of an isocyanate compound. Preferred are hydrophobic isocyanate compounds, and more preferred are tolylene diisocyanate, methylene bisdiphenyl diisocyanate, polymethylene phenyl polyisocyanate, and polymers thereof.
The isocyanate compound (2) is 1 to 150 parts by mass with respect to 100 parts by mass of the solid content of the aqueous emulsion (1). Adhesive performance is good at 1 part by mass or more, and pot life is good at 150 parts by mass or less. Preferably it is 2-100 mass parts.

In order to improve performance, the following materials may be blended in the aqueous emulsion and composition of the present invention. For example, water-soluble resins, solvents, plasticizers, antifoaming agents, thickeners, leveling agents, dispersants, colorants, water resistance agents, lubricants, pH adjusters, preservatives, inorganic pigments, organic pigments, surface activity And crosslinking agents other than isocyanate and isocyanate compounds, such as epoxy compounds and polyvalent metal compounds.
Examples of the water-soluble resin used in the present invention include polyvinyl alcohols such as polyvinyl alcohol, ethylenic polyvinyl alcohol, and silanol-modified polyvinyl alcohol, cellulose resins (methyl cellulose, ethyl cellulose, hydroxy cellulose, carboxy cellulose, etc.), chitin, chitosan, Mention may be made of starches, polyethylene glycol, polypropylene glycol, polyvinyl ether, gelatin, caseins, cyclodextrins, aqueous nitrified cotton and the like. Polyvinyl alcohol may be completely saponified or partially saponified. Polyvinyl alcohol is particularly preferable.
Examples of inorganic or organic pigments include inorganic oxides such as magnesium, calcium, zinc, barium, titanium, aluminum, antimony, lead, and other metal oxides, hydroxides, sulfides, carbonates, sulfates, and silicate compounds. Is mentioned. Specific examples include calcium carbonate, kaolin, talc, titanium dioxide, aluminum hydroxide, silica, gypsum, barite powder, alumina white, and satin white. Examples of organic pigments include solid polymer fine powders such as polystyrene, polyethylene, and polyvinyl chloride.

The present invention will be described based on examples. However, the embodiments of the present invention are not limited thereto. In addition, all the parts in the examples indicate the number of parts as they are (that is, the aqueous emulsion is the number of parts containing water itself). “Part” means “part by mass” unless otherwise specified.
[Measurement of physical properties]
Each characteristic was calculated | required as follows.
(1) Particle size:
Measurement was performed by a light scattering method.
The measuring apparatus used the particle size measuring device (the product made by LEED & NORTHRUP, MICROTRACTMUPA150), and measured the volume average particle diameter.
(2) Pot life:
10 to 25 parts of MR-100 (manufactured by Nippon Polyurethane Co., Ltd., polymethylene phenyl polyisocyanate) (registered trademark) as an isocyanate compound is blended with 100 parts by mass of the main component having the composition shown below, and vigorously stirred for 5 minutes. .
Then, it is left at 20 ° C. and the time until gelation is observed. 90 minutes or more are accepted. Note that the gelation was judged by lightly stirring with a spatula every 15 minutes and when stirring became impossible.
Composition of main ingredient Aqueous emulsion (solid content 50%) 60 parts by mass
Polyvinyl alcohol (solid content 15%) 20 parts by mass
20 parts by mass of calcium carbonate PVA217 (registered trademark) manufactured by Kuraray Co., Ltd. was used as polyvinyl alcohol. In addition, the manufacturing method of the main ingredient is as follows. First, calcium carbonate is added while stirring the aqueous emulsion, and stirring is performed for 10 minutes. Next, polyvinyl alcohol was added with stirring, and stirring was further performed for 10 minutes.

(3) Adhesion test:
a. Normal adhesiveness (2) The compound used in the pot life test (used within 10 minutes after mixing of isocyanate) was used as an adhesive. Test conditions were based on JISK6806: 2003 5.11.1. However, the static value after decompression was 14 days.
b. Boiling resistance test: The blended product used in the pot life test of (2) (used within 10 minutes after mixing of isocyanate) was used as an adhesive. Test conditions were based on JISK6806: 2003 5.11.1. However, immersion in boiling water was performed under the following conditions. The test piece is immersed in boiling water for 4 hours, then dried in air at 60 ± 3 ° C. for 20 hours, and further immersed in boiling water for 4 hours. Thereafter, it was again dried in air at 60 ± 3 ° C. for 20 hours, further immersed in boiling water for 4 hours, and then tested in a wet state.
(4) Storage stability test after pigment blending For the storage stability test, the following main compound blend was prepared. The preparation of the main agent was the same as that described in (2), but after all the materials were added, stirring was performed for 2 hours. After that, it was left in a dryer at 60 ° C. for 4 weeks, and the ratio of the viscosity at 20 ° C. immediately after production to the viscosity at 20 ° C. after standing for 4 weeks (viscosity (after 4 weeks) / viscosity (immediately after production)). Asked.
Composition of main ingredient Aqueous emulsion (solid content 50%) 40 parts by mass (for storage stability) Polyvinyl alcohol (solid content 15%) 20 parts by mass
40 parts by weight of calcium carbonate

[Production of aqueous emulsions 1 to 10]
Aqueous emulsions 1-7 were prepared as follows. In 1000 parts by mass of all monomers shown in Table 1, 25 parts by mass of 20% aqueous solution of Emulgen 150 (manufactured by Kao Corporation, polyoxyethylene alkyl ether), Aqualon KH-10 (Daiichi Kogyo Seiyaku Co., Ltd.), 80 parts by mass of a 25% aqueous solution of ammonium α-sulfonato-ω-1- (allyloxymethyl) alkyloxypolyoxyethylene), Adekari Soap SR-10 (Asahi Denka Co., Ltd., α-sulfo-ω- (1 -(Alkoxy) methyl-2- (2-propenyloxy) ethoxy) -ammonium salt of poly (oxy-1,2-ethanediyl)) 40 parts by mass, ammonium peroxodisulfate 3 parts by mass, water 440 parts by mass And stirred with a homomixer to prepare a pre-emulsion solution.
Separately, an aqueous dispersion of seed particles (average particle size 50 nm methyl methacrylate / butyl acrylate = 50/45 (mass ratio) polymer solid content 35%) was added to a reaction vessel equipped with a stirrer and a temperature control jacket. Then, 350 parts by mass of water was charged, the internal temperature was raised to 80 ° C., and 0.5 part by mass of ammonium peroxodisulfate dissolved in 25 parts by mass of water was added. To this was added the pre-emulsion at a constant flow rate over 4 hours. Thereafter, the temperature was maintained at 80 ° C. for 1 hour, and further dissolved 1 part by weight of ammonium peroxodisulfate and 25 parts by weight of water were added, and polymerization was continued at the same temperature for 1 hour. After 1 hour, the mixture was cooled and a 10% strength by weight aqueous sodium hydroxide solution was added to adjust the pH to 7. Thereafter, filtration was carried out using a 200-mesh wire net, and then water was blended so that the solid content was 50% by mass to obtain an aqueous emulsion having the physical properties shown in Table 1.

When preparing the pre-emulsion liquid similarly to the aqueous emulsions 1 to 7, the aqueous emulsion 8 was 25 parts by mass of 20% aqueous solution of Emulgen 150 (manufactured by Kao Corporation, polyoxyethylene alkyl ether), Emar D-3-D. 100 parts by mass (manufactured by Kao Corporation, 25% aqueous solution of sodium polyoxyethylene alkyl ether sulfate) was used. Subsequent operations were performed in the same manner as aqueous emulsions 1-7.
As the aqueous emulsion 9, pre-emulsified liquids were prepared in the same manner as the aqueous emulsions 1-7. Instead of seed particles, 20 parts by mass of 20% aqueous solution of Emulgen 150 and 5 parts by mass of sodium dodecylbenzenesulfonate were charged into the reaction vessel. Subsequent operations were performed in the same manner as aqueous emulsions 1-7.
The aqueous emulsion 10 produced the pre-emulsion liquid similarly to the aqueous emulsions 1-7. A reaction vessel was charged with 20 parts by mass of a 150 nm particle size emulsion (styrene / methyl methacrylate / butyl acrylate = 10/40/45 (mass ratio) polymer solid content 50%). Subsequent operations were performed in the same manner as aqueous emulsions 1-7.
The physical properties of the obtained aqueous emulsions 8 to 10 are shown in Table 1.

[Examples 1 to 9]
Using the aqueous emulsions 1 to 7 shown in Table 1, main ingredients of the composition composition shown in Table 2 were prepared, and the above (2) pot life and (3) adhesion test were conducted. The evaluation results are shown together in Table 2.
[Comparative Examples 1-2]
Using the water-based emulsions 9 to 10 shown in Table 1, the main ingredients of the composition composition shown in Table 3 were prepared, and the above (2) pot life and (3) adhesion test were conducted. The evaluation results are shown together in Table 3.
Comparative Example 1 is an example using an aqueous emulsion 9 having an average particle diameter of less than 200 nm, and Comparative Example 2 is an example using an aqueous emulsion 10 having an average particle diameter exceeding 600 nm.
[Examples 10 to 16, Comparative Example 3]
Using the aqueous emulsions 1 to 8 shown in Table 1, the storage stability test after the pigment blending of the above (4) was carried out. The evaluation results are shown in Table 4.
Comparative Example 3 is an example using an aqueous emulsion 8 obtained without using a reactive surfactant.

  The aqueous emulsion and composition thereof of the present invention are suitable as an adhesive for wood such as plywood and laminated wood. Other than that, for example, for particle board, corrugated board, metal foil bonding, paper, cloth, textile processing, ceramics, inorganic board, PVC, plastic sheet such as polypropylene, glass board, etc. It can also be suitably used as an adhesive.

Claims (3)

  Monomer composition containing one or more monomers selected from aromatic vinyl monomers and (meth) acrylic acid ester monomers, hydroxyl group-containing vinyl monomers, and unsaturated carboxylic acid monomers Is an aqueous emulsion (1) obtained by emulsion polymerization using a reactive surfactant, wherein the aqueous emulsion (1) has an average particle size of 200 to 600 nm. Aqueous emulsion.   2. The aqueous emulsion for adhesives according to claim 1, wherein the hydroxyl group-containing vinyl monomer is 0.5 to 5% by mass in the total monomer composition.   An adhesive composition comprising the aqueous emulsion (1) according to claim 1 or 2 and an isocyanate compound (2).