TWI548652B - Aqueous adhesive composition and manufacturing method thereof - Google Patents

Description

Aqueous adhesive composition and a method of producing the same.

The present invention relates to an aqueous adhesive composition and a method of producing the same.

Adhesives are classified into a plurality of types, and each of the adhesives has different properties such as adhesion, retention, heat resistance, moist heat resistance, and water resistance. Among them, the acrylic adhesive is widely used because of its excellent adhesion or holding power. An acrylic pressure-sensitive adhesive can be obtained by emulsion polymerization of an acrylic monomer or the like. In particular, in order to further improve the adhesion of the acrylic adhesive, a technique of including a tackifier (Tackifying Resin) in an emulsion polymerization reaction system has been proposed (for example, Patent Document 1~) Patent Document 3).

These proposed techniques are a method of emulsion polymerization using a large amount of polyoxyethylene rosin ester, or dissolving the adhesive in a monomer and finely dispersing the emulsified droplets with a high-pressure homogenizer. A method of emulsion polymerization (so-called microemulsion polymerization), thereby obtaining an acrylic pressure-sensitive adhesive.

[Previous Technical Literature] [Patent Document]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 8-301950

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-348551

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2003-327933

However, in the above technique, it is difficult to simultaneously improve water resistance and adhesion. In addition, in the above technique, it is required to dissolve in the monomer during emulsion polymerization. The complicated steps of dissolving the adhesive and further dispersing it, and thus the productivity is poor.

The present invention has been made in view of the above problems, and an object thereof is to provide a technique relating to an adhesive having high water resistance and high adhesion.

The present invention is an aqueous adhesive composition as shown below and a method for producing the same.

[1] An aqueous adhesive composition comprising: a copolymerization dispersion which is made up of a reaction system containing 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm; The emulsion polymerization is carried out: (a) 0.1 parts by mass to 10 parts by mass of the ethylenically unsaturated carboxylic acid monomer, and (b) 60 parts by mass to 99 parts by mass of the acrylate monomer having 4 to 12 carbon atoms of the alkyl group and (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass), and the average particle diameter of the particles contained in the copolymerized dispersion is 0.3 In the range of μm to 10 μm, the glass transition point of the copolymerization dispersion is -70 ° C to -30 ° C, and the insoluble matter when the copolymerization dispersion is dissolved in tetrahydrofuran is 70% by mass or less.

[2] The aqueous adhesive composition according to the above [1], which comprises a crosslinking agent.

[3] A method for producing an aqueous adhesive composition, comprising: dispersing 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm in a medium to form a dispersion, and dispersing the dispersion To the liquid, (a) 0.1 parts by mass to 10 parts by mass of the ethylenically unsaturated carboxylic acid monomer, and (b) 60 parts by mass of the acrylate monomer having 4 to 12 carbon atoms in the alkyl group are added. ~99 parts by mass and (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass), and emulsion polymerization is carried out to obtain a total of Polymerization dispersion.

[4] A method for producing an aqueous adhesive composition, comprising: (a) an ethylenically unsaturated carboxylic acid monomer in an amount of from 0.1 part by mass to 10 parts by mass, and (b) an alkyl group having a carbon number of from 4 to 12; 60 parts by mass to 99 parts by mass of the body, (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass), a medium, and an emulsifier In the pre-emulsion, 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm is added and emulsion polymerization is carried out to obtain a copolymerization dispersion.

[5] The method for producing an aqueous adhesive composition according to the above [3] or [4], which comprises adding a bridging agent to the copolymerization dispersion.

The aqueous adhesive composition of the present invention has both high water resistance and high adhesion. According to the method for producing an aqueous adhesive composition of the present invention, an aqueous adhesive composition having both high water resistance and high adhesion can be obtained through a simple procedure.

Embodiments of the present invention will be described below. The present invention is not limited to the embodiments described below, and modifications, corrections, and improvements can be made without departing from the scope of the invention.

The aqueous adhesive composition of the present invention contains a copolymerized dispersion which is a water-insoluble adhesive having an average particle diameter of 0.05 μm to 1.00 μm. In the reaction system of the mass parts to 10 parts by mass, the following monomers are obtained by emulsion polymerization: (a) 0.1 parts by mass to 10 parts by mass of the ethylenically unsaturated carboxylic acid monomer, and (b) the carbon number of the alkyl group is 4 to 12 60 parts by mass to 99 parts by mass of the acrylate monomer and (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass). Further, in the aqueous adhesive composition of the present invention, the copolymerization dispersion has a glass transition point of -70 ° C to -30 ° C, and the insoluble matter when dissolved in tetrahydrofuran is 70% by mass. Further, in the aqueous adhesive composition of the present invention, the average particle diameter of the particles contained in the copolymerization dispersion is from 0.3 μm to 10 μm.

The copolymerization dispersion in the present specification means particles of an acrylic copolymer or a particle of a water-insoluble binder obtained by copolymerizing the component (a), the component (b) and the component (c) or an acrylic copolymer. The particles of the water-insoluble adhesive and the like are dispersed in a medium such as water.

Here, the average particle diameter of the particles contained in the copolymerization dispersion means particles of the acrylic copolymer or particles of the water-insoluble binder or particles including the acrylic copolymer and the water-insoluble binder. The average particle diameter of all the particles contained in the copolymerization dispersion as a measurement target. Further, the average particle diameter of the particles contained in the copolymerized dispersion proposed in the present specification means the volume average particle diameter measured by diffraction and scattering of the laser.

In addition, the average particle diameter of the particles contained in the copolymerization dispersion of the aqueous adhesive composition of the present invention is from 0.3 μm to 10 μm, and the stability and the drying property are good. In particular, from the viewpoint of being able to find moderate viscosity and high water resistance, the copolymerization dispersion in the aqueous adhesive composition of the present invention The average particle diameter of the particles is preferably from 0.5 μm to 5 μm, more preferably from 1.0 μm to 3.0 μm. When the average particle diameter of the particles contained in the copolymerization dispersion is 0.3 μm or more, the copolymerization dispersion cannot be made to have a high viscosity, and therefore, the solid content in the copolymerization dispersion can be increased. When the average particle diameter of the particles contained in the copolymerization dispersion is 10 μm or less, the viscosity of the copolymerization dispersion cannot be made too low, and an appropriate viscosity can be obtained.

Further, in the aqueous adhesive composition of the present invention, by using a water-insoluble adhesive having an average particle diameter of 0.05 μm to 1.00 μm in a reaction system for obtaining an emulsion polymerization of a copolymerized dispersion, the copolymerization reaction is not carried out. The particles of the water-soluble adhesive are carried out as a seed.

In the aqueous adhesive composition of the present invention, the copolymerization dispersion is obtained by using 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm (wherein (a) a vinyl group The reaction system is emulsified in a reaction system in which the unsaturated carboxylic acid monomer, the (b) alkyl group having an alkyl group having 4 to 12 carbon atoms, and (c) the total amount of the ethylenically unsaturated monomer is 100 parts by mass. Those who have been polymerized have become highly adhesive and highly water-resistant.

In particular, the aqueous adhesive composition of the present invention comprises, in the reaction system for obtaining the emulsion polymerization of the copolymerized dispersion, in the case where the water-insoluble adhesive is contained in an amount of 0.1 part by mass or more, the aqueous adhesive composition The adhesion of the object becomes very high. Further, the aqueous adhesive composition of the present invention, in the reaction system for obtaining the emulsion polymerization of the copolymerized dispersion, in the case where the water-insoluble adhesive is contained in an amount of 10 parts by mass or less, the aqueous adhesive composition The water resistance becomes very high.

Further, from the viewpoint of simultaneously improving the adhesion and water resistance, the aqueous adhesive composition of the present invention is preferably a water-insoluble adhesive contained in a reaction system for obtaining an emulsion polymerization of a copolymerized dispersion. The amount is from 1.0 part by mass to 5.0 parts by mass (wherein (a) an ethylenically unsaturated carboxylic acid monomer, (b) an alkyl group having an alkyl group having 4 to 12 carbon atoms, and (c) an ethylene group The total amount of the saturated monomers was set to 100 parts by mass].

Further, the water-absorbent composition of the aqueous adhesive composition of the present invention having an average particle diameter of 0.05 μm to 1.00 μm contained in the reaction system for obtaining the emulsion polymerization of the copolymerization dispersion is not used in the emulsion polymerization. The water-soluble adhesive becomes easy to disperse. Therefore, in the reaction system of the emulsion polymerization, even if the water-insoluble binder is present in an amount of only 0.1 part by mass to 10 parts by mass, the stability at the time of polymerization is good and the inhibition of the copolymerization reaction can be suppressed.

In the emulsion polymerization for obtaining a copolymerized dispersion, the water-insoluble adhesive may be previously dispersed in a medium such as water, or may be added to a monomer-containing pre-emulsion. The copolymerized dispersion obtained by the emulsion polymerization in such a manner imparts high adhesion and high water resistance to the aqueous adhesive composition of the present invention.

Further, emulsion polymerization for obtaining a copolymerized dispersion in the aqueous adhesive composition of the present invention from the viewpoint of obtaining dispersion stability of the water-insoluble adhesive and having an appropriate average particle diameter of the acrylic copolymer The average particle diameter of the water-insoluble binder contained in the reaction system is preferably from 0.10 μm to 0.80 μm.

The average particle diameter of the water-insoluble binder referred to in this specification means the volume average particle diameter measured by laser diffraction and scattering.

Further, the aqueous adhesive composition of the present invention can sufficiently increase the adhesion and water resistance by the following: the carbon number of the (a) ethylenically unsaturated carboxylic acid monomer and the (b) alkyl group is 4~ The total amount of the acrylate monomer of 12 and (c) the ethylenically unsaturated monomer is 100 parts by mass, and the amount of the (a) ethylenically unsaturated carboxylic acid monomer is from 0.1 part by mass to 10 parts by mass.

Further, the aqueous adhesive composition of the present invention has a glass transition point of -70 ° C to -30 ° C by the copolymerization dispersion, and an anchorage dependence or an adhesive force is improved.

The (a) ethylenically unsaturated carboxylic acid monomer which can be used for the aqueous adhesive composition of the present invention is an α,β unsaturated carboxylic acid. For example, as the (a) ethylenically unsaturated carboxylic acid monomer which can be used for the aqueous adhesive composition of the present invention, acrylic acid, methacrylic acid, itaconic acid, maleic acid can be cited. (maleic acid), fumaric acid, mono[2-(meth)acryloyloxyethyl]phthalate, semi-ester, succinic acid Mono[2-(meth)acryloyloxyethyl]succinate, carboxyethyl acrylate, and the like. These ethylenically unsaturated carboxylic acid monomers may be used singly or in combination of two or more kinds. Among the ethylenically unsaturated carboxylic acid monomers exemplified herein, the stability at the time of polymerization is good, and from the viewpoint of improving water resistance, acrylic acid or methacrylic acid is preferably used in the present invention.

As the acrylate monomer having 4 to 12 carbon atoms of the (b) alkyl group which can be used in the aqueous adhesive composition of the present invention, butyl acrylate can be cited. N-butylacrylate, i-butylacrylate, t-butylacrylate, 2-ethylhexylacrylate, n-octylacrylate, acrylic acid Isoonylacrylate and laurylacrylate. In the acrylate monomer having 4 to 12 carbon atoms of the alkyl group exemplified herein, it is preferred to use 2-ethyl hexyl acrylate or n-octyl acrylate or acrylic acid from the viewpoint of improving adhesion or water resistance. An oxime ester is used in the present invention.

The (c) ethylenically unsaturated monomer which can be used in the aqueous adhesive composition of the present invention is an acrylic acid having a carbon number of 4 to 12 which may be (a) an ethylenically unsaturated carboxylic acid monomer or (b) an alkyl group. A monomer in which an ester monomer is copolymerized.

For example, (c) the ethylenically unsaturated monomer which can be used for the aqueous adhesive composition of the present invention may, for example, be methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate or isopropyl acrylate. An alkyl acrylate or an alkyl methacrylate having an alkyl group such as an ester or isopropyl methacrylate of 3 or less; a cycloalkyl (meth) acrylate such as cyclohexyl (meth)acrylate; Aromatic (meth) acrylate such as phenoxymethyl (meth) acrylate and benzyl (meth) acrylate; hydroxyalkyl acrylate, methyl Hydroxyalkylmethacrylate, polyoxyethylene (meth)acrylate, methoxyethylacrylate, ethoxymethylacrylate, glycidyl acrylate (glycidylacrylate) and aliphatic (meth) acrylates such as glycidylmethacrylate; acrylamide, methacrylamide, N-methylol acrylamide (N -methylolacrylamide), N-methoxymethylacrylamide, and (meth)acrylamide such as N-methoxybutylacrylamide; vinyl methyl ketone (vinylmethylketone), vinylethylketone, vinyl-n-propylketone, vinyl-i-propylketone, vinyl-n-butylketone, Vinyl-i-butylketone, vinyl-t-butylketone, vinylphenylketone, vinylbenzylketone, divinyl ketone (alvinylketone) and acetal (rado)-based radical polymerizable monomers such as diacetone acrylamide; (meth)acrylonitrile ((meth)acrylonitrile) ), Crotonnitrile, 2-cyanoe (meth)acrylate (2-cyanoe) Nitrile containing thyl(meth)acrylate), 2-cyanopropyl(meth)acrylate, and 3-cyanopropyl(meth)acrylate Unsaturated compound; styrene, o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, p-vinyltoluene (p-ethylvinylstyrene), mono-vinyl aromatic compounds such as α-methylstyrene and α-fluorostyrene; vinyl chloride, vinylidene chloride, etc. Vinyl halides, vinyl esters such as vinyl propionate, and the like.

The aqueous adhesive composition of the present invention can be used as the ethylenically unsaturated sulfonic acid monomer as the (c) ethylenically unsaturated monomer, and examples thereof include isoprene sulfonic acid (isoprene sulfonic acid). Acid), styrene-3-sulfonic acid, styrene-4-sulfonic acid, α-methylstyryl-3-sulfonic acid ( Α-methylstyrene-3-sulfonic acid), α-methylstyrene-4-sulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid (2- Acrylamide-2-methylpropanesulfonic acid) or allyl alkyl sulfonic acid, polyoxyethylene alkyl allyl ether sulfates and polyoxyethylene polyoxypropylene groups Sulfate of polyoxyethylene polyoxypropylene alkyl allyl ether. These ethylene-based unsaturated sulfonic acid monomers may be used singly or in combination of two or more kinds in the invention.

Further, in the aqueous adhesive composition of the present invention, (c) the ethylenically unsaturated monomer may be a salt of the above-mentioned ethylenically unsaturated sulfonic acid monomer, for example, a sodium salt or a potassium salt of an ethylenically unsaturated sulfonic acid monomer. Salt and ammonium salts, etc. These salts of the ethylenically unsaturated sulfonic acid monomers may be used singly or in combination of two or more kinds in the invention.

Further, as the (c) ethylenically unsaturated monomer which can be used in the aqueous adhesive composition of the present invention, caprolactone denatured acetoxy (meth)acrylate can be exemplified. Or a carbonyl group-containing unsaturated compound such as PCL ATFA1, PCL ATFA2, PCL ATFM1, and PCL ATFM2 (manufactured by Daicel Corporation); γ-glycidoxypropyltrimethoxysilane , γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane Γ-methacryloxypropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 3,4-epoxy 3,4-epoxycyclohexylethyltrimethoxysilane, 3,4-epoxycyclohexylethyltriethoxysilane ), vinyltrimethoxysilane, vinyltriethoxysilane, etc. Among the ethylenically unsaturated monomers listed herein, from the viewpoints of water resistance, adhesion, or retention Preferably, methyl methacrylate, hydroxyalkyl methacrylate, methoxyethyl acrylate, ethoxyethyl acrylate, γ-methacryloxypropyltrimethoxydecane, and γ-methyl are preferred. Acryloxypropyltriethoxydecane is used in the present invention.

The water-insoluble adhesive which can be used for the aqueous adhesive composition of the present invention may, for example, be natural rosin such as gum rosin, tall oil rosin, and wood rosin or a modified product in which various rosin such as polymerized rosin and sulfonic compound such as hydrogenation, dehydration or dimerization, or the like, or maleic acid or maleic anhydride relative to rosin (maleic) Addition reactants such as anhydride), fumaric acid, acrylic acid, etc., and the ester, partial ester or partial guanamine compound, and terpene phenol. These water-insoluble adhesives may be used singly or in combination of two or more kinds in the invention. Among the water-insoluble binders exemplified herein, from the viewpoint of adhesion, it is preferred to use an aqueous dispersion of indophenol and polymerized rosin for the present invention.

Further, the aqueous adhesive composition of the present invention may also contain a bridging agent. In particular, the aqueous adhesive composition of the present invention preferably contains 0.1 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm in a reaction system for obtaining an emulsion polymerization of a copolymerized dispersion. 10 parts by mass and containing a bridging agent before coating. The bridging agent can improve the anchoring and retaining force in the presence of the coating agent.

As a bridging agent which can be used in the aqueous adhesive composition of the present invention, a conventional bridging agent such as a polyfunctional isocyanate bridging agent or an epoxy bridging agent or an oxazoline can be used. A bridging agent, an aziridine bridging agent, a chelate bridging agent, and a diterpene compound such as adipic acid dihydrazide. The bridging agent can be oil soluble And water soluble either. In the present invention, the bridging agent may be used singly or in combination of two or more kinds. As a bridging agent, for example, the following compounds can be used in the present invention: among the epoxy resin bridging agents, in particular, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl (polyethylene glycol diglycidyl) Ether), propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol 1,6-hexanediol diglycidyl ether, dibromo neopentyl glycol diglycidyl ether, o-phthalic acid diglycidyl ester , glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, polyglycerol polyglycidyl Ether), sorbitol polyglycidyl ether, N, N, N', N -tetraglycidyl-m-dimethyldiamine (N,N,N',N'-tetraglycidyl-m-xylylenediamine), N,N,N',N'-tetraglycidyl di-ethyl Triamine (N, N, N', N'-tetraglycidyldiethylenetriamine) and N, N, N', N'-tetraglycidyl ethyl diamine (N, N, N', N'-tetraglycidylethylenediamine) Two or more epoxy polyglycidyl compounds. Listed here Among the bridging agents, polyglycerol polyglycidyl ether and polyethylene glycol diglycidyl ether are preferably used in the present invention from the viewpoint of improving the mixing property or adhesion.

Further, the aqueous adhesive composition of the present invention is various additives for a general aqueous adhesive composition, such as a white pigment, a tackifier, a wetting agent, an alkali agent, a stabilizer, and an emulsifier, The water-insoluble adhesive may also contain other kinds of adhesives, preservatives and mold inhibitors.

In the case of using the aqueous adhesive composition of the present invention to form an adhesive layer of a label, a sheet, and a tape, it can be used as a substrate for an adhesive label, an adhesive sheet, and an adhesive tape. Paper, cloth, polyvinyl chloride, polypropylene, polyester, polyamide, foam and metal foil. Further, examples of the adherend of the adhesive label, the adhesive sheet, and the adhesive tape include plastic, metal, paper, glass, silicone, ceramic, and skin.

The aqueous adhesive composition of the present invention can be obtained, for example, by the following production method.

The copolymerization dispersion contained in the aqueous adhesive composition of the present invention can be obtained by the following method: (a) the ethylenically unsaturated carboxylic acid monomer and the (b) alkyl group have a carbon number by emulsion polymerization. A mixture of 4 to 12 acrylate monomers and (c) a mixture of ethylenically unsaturated monomers (hereinafter referred to as "mixture of monomers") is subjected to a polymerization reaction.

Specifically, in the present invention, a mixture of monomers and water are emulsified using an emulsifier, whereby a pre-emulsion is prepared, and non-water is added to the pre-emulsion. A soluble binder or a polymerization initiator or a molecular weight regulator is then subjected to polymerization in a generally non-active environment. As a result, a copolymerized dispersion comprising particles of an acrylic copolymer or particles of a water-insoluble binder or particles comprising an acrylic copolymer and a water-insoluble binder can be obtained.

Alternatively, in the present invention, a dispersion in which a water-insoluble binder is dispersed may be previously prepared in a medium (for example, water), and a mixture of monomers and an emulsifier may be added to the dispersion while being subjected to emulsion polymerization. The polymerization was carried out (see the examples for details).

The above two types of emulsion polymerization methods can be suitably carried out in the following cases, as follows: a step of pulverizing the binder and dissolving it in the monomer or a high pressure homogenizer or the like without passing through A step of dispersing the emulsified droplets. That is, the present invention can easily carry out emulsion polymerization.

In the present invention, the polymerization reaction can be carried out while continuously or intermittently supplying the pre-emulsion and the polymerization initiator in the reaction system.

In the present invention, a single persulfate or redox polymerization initiator may be used in the polymerization initiator. The redox polymerization initiator is a polymerization initiator which combines an oxidizing agent and a reducing agent. Here, the oxidizing agent used for the redox polymerization initiator may be used in combination of one or more kinds. Further, the reducing agent used for the redox polymerization initiator may be used in combination of one or more kinds.

As an oxidizing agent for a redox polymerization initiator, for example, Listed as persulfate of potassium persulfate, sodium persulfate and ammonium persulfate; hydrogen peroxide, t-butylhydroperoxide, t-butyl maleate (t -butylperoxymaleic acid), succinic acid peroxide, benzoyl peroxide, cumene hydroperoxide, diisopropyl peroxy dicarbonate , cumyl peroxy neodecanoate, cumyl peroxy octoate, diisopropylbenzene hydroperoxide, p-mantidine hydroperoxide (p) -menthane hydroperoxide), peroxidation of 2,2-bis(4,4-di-t-butylperoxidecyclohexylpropane) Things.

On the other hand, examples of the reducing agent for the redox polymerization initiator include sodium hydrogen sulfite, sodium dithionite, and sodium thiosulfate. And reducing sugars such as rongalite, ascorbic acid, and fructose, and iron salts such as ferrous sulfate and ferric sulfate. Further, in the case of use in a redox polymerization initiator, a chelating agent such as sodium ethylenediamine tetraacetate may be used in combination.

The copolymerization dispersion contained in the aqueous adhesive composition of the present invention is obtained In the case of using a redox polymerization initiator in the polymerization reaction, the combination of the above-exemplified oxidizing agent, reducing agent and chelating agent is preferably, for example, the following three groups (A to C). . (Combination A) Persulfate, sodium hydrogen sulfite and ferrous sulfate (combination B) tert-butyl hydroperoxide, sodium hydrogen sulfite and ferrous sulfate (combination C) p-manganese hydroperoxide, sulphate Sodium ethylene sulphate and sodium formaldehyde sulfoxylate

In the present invention, the redox polymerization initiator is used in a proportion of (a) an ethylenically unsaturated carboxylic acid monomer, (b) an alkyl group having an alkyl group having 4 to 12 carbon atoms, and (c) ethylene. The total amount of the unsaturated monomers is 100 parts by mass, preferably 0.01 parts by mass to 5.0 parts by mass, more preferably 0.05 parts by mass to 3.0 parts by mass, still more preferably 0.1 parts by mass to 1.0 part by mass. Further, in the present invention, in the case where the oxidizing agent for the redox polymerization initiator is a single persulfate, the carbon number of the (a) ethylenically unsaturated carboxylic acid monomer and (b) alkyl group The amount of the redox polymerization initiator to be used is preferably from 0.1 part by mass to 1.0 part by mass based on 100 parts by mass of the total of the acrylate monomer of 4 to 12 and (c) the ethylenically unsaturated monomer.

When the copolymerization dispersion contained in the aqueous adhesive composition of the present invention is obtained, examples of the emulsifier which can be used in the polymerization reaction include polyoxyethylene alkyl ether and polyoxyethylene alkyl sulfate. Polyoxyethylene alkyl sulfuric acid ester salt, polyoxyethylene polycyclic phenyl ether sulfuric acid ester salt, sodium polyoxyethylene alkyl succinate, sodium lauryl sulfate Surfactant such as lauryl sulfate) and sodium dodecylbenzenesulfonate. For example, any of the following reactive emulsifiers can be used: "LATEMUL S-180A" and "PD-104" manufactured by Kao Corporation (Company); "ELEMINOL" manufactured by Sanyo Chemical Co., Ltd. -2"; "Acualon KH-10" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.; "ADEKA RIA SOAP SE-10N" and "SR-10N" manufactured by Asahi Kasei Kogyo Co., Ltd. "Antox MS-60" manufactured by NIPPON NYUKAZAI CO., LTD.; "Surfmer FP-120" manufactured by TOHO CHEMICAL INDUSTRY COMPANY, LIMITED.

In the present invention, the emulsifier is used in a proportion of (a) an ethylenically unsaturated carboxylic acid monomer, (b) an alkyl group having an alkyl group having 4 to 12 carbon atoms, and (c) an ethylenically unsaturated monomer. The total amount is 100 parts by mass, preferably 0.2 parts by mass to 7.0 parts by mass, more preferably 0.5 parts by mass to 5.0 parts by mass, still more preferably 0.7 parts by mass to 3.0 parts by mass.

When the copolymerization dispersion contained in the aqueous adhesive composition of the present invention is obtained, examples of the molecular weight modifier which can be used in the polymerization reaction include butyl mercaptan, dodecyl mercaptan, and hydrogen sulfur. Octyl thioglycollate, isopropyl alcohol, methanol, and carbon tetrachloride.

In the present invention, the molecular weight modifier is used in a proportion of (a) an ethylenically unsaturated carboxylic acid monomer, (b) an alkyl group having an alkyl group having 4 to 12 carbon atoms, and (c) an ethylenic unsaturated monomer. The total amount of the body is 100 parts by mass, It is preferably 0.001 parts by mass to 0.50 parts by mass, more preferably 0.003 parts by mass to 0.30 parts by mass, still more preferably 0.005 parts by mass to 0.20 parts by mass.

In the case of the present invention, by appropriately selecting the kind or the use ratio of the molecular weight modifier, a weight average molecular weight (Mw) of a desired size or a copolymerized dispersion in which particles of the acrylic copolymer are dispersed can be obtained, The acrylic copolymer has tetrahydrofuran insoluble matter (THF insoluble matter).

According to the aqueous adhesive composition of the present invention, sufficient adhesion and water resistance can be obtained, and a high cohesive force can be obtained by the interaction of carboxyl groups in the particles of the acrylic copolymer. As a result, a good holding power can be obtained by the aqueous adhesive composition of the present invention. Further, according to the aqueous adhesive composition of the present invention, since the tetrahydrofuran insoluble matter (THF insoluble matter) is 70% or less, when the adhesive layer is formed, high penetration force to the substrate can be obtained, and as a result, Good anchoring can be obtained. Further, according to the method for producing an aqueous adhesive composition described above, the above-described aqueous adhesive composition excellent in water resistance and adhesion can be produced with high productivity.

[example]

The invention will be described in detail below based on examples, but the invention is not limited to the examples.

(1) Raw materials

The following materials were used in the examples and comparative examples.

(1-1) Monomer:

(a) component (ethylene-based unsaturated carboxylic acid monomer):

Acrylic (manufacturer: TOAGOSEI CO., LTD.)

Methacrylic acid (manufacturer: KURARAY CO., LTD)

(b) component (acrylate monomer): 2-ethyl hexylacrylate (manufacturer: TOAGOSEI CO., LTD.)

Butyl acrylate (manufacturer: TOAGOSEI CO., LTD.)

(c) component (ethylene unsaturated monomer): methyl methacrylate (manufactured by: Mitsubishi Rayon Co., Ltd.)

Styrene (manufacturer: Mitsubishi Chemical Corporation)

Methoxyethyl acrylate (manufacturer: OSAKA ORGANIC CHEMICAL INDUSTRY LTD.)

Γ-methacryloxy propyl trimethoxysilane (manufactured by Shin-Etsu Silicon Co., Ltd.).

2-hydroxyethyl methacrylate (manufacturer: OSAKA ORGANIC CHEMICAL INDUSTRY LTD.)

(1-2) Water-insoluble adhesive:

Indophenol E200-NT (average particle diameter 0.66 μm, manufactured by ARAKAWA CHEMICAL INDUSTRIES, LTD.)

Polymerized rosin E865-NT (average particle diameter 0.66 μm, manufactured by ARAKAWA CHEMICAL INDUSTRIES, LTD.)

(1-3) Rosin-based emulsifier for water-soluble emulsion polymerization:

Add ethylene oxide rosin ester DRA-1500 (The particle diameter cannot be measured in an aqueous solution, and the place of manufacture: TOHO CHEMICAL INDUSTRY COMPANY, LIMITED)

(1-4) Emulsifier:

Non-reactive emulsifier: Newcol. 707SF (manufacturer: NIPPON NYUKAZAI CO., LTD.)

Reactive emulsifier: KH-1025 (manufacturer: Dai-ichi Kogyo Seiyaku Co., Ltd.)

(1-5) Other:

Tackifier: UH-420 (manufacturer: ADEKA CORPORATION)

Wetting agent: Surflon S234 (manufacturer: AGC SEIMI CHEMICAL CO., LTD.)

(2) Copolymerization (Example 1 to Example 3 and Comparative Example 1 to Comparative Example 4)

In Examples 1 to 3 and Comparative Examples 1 to 4, the monomers of the components (a) to (c) and the water-insoluble binder were mixed and reacted at a ratio shown in Table 1 (in addition, Table The numerical value shown in 1 is a mass part, and the total of the monomers of the components (a) to (c) is 100 parts by mass. In addition, as for the numerical value of the "mass part" mentioned below, the sum total of the monomer of (a) component - (c) component is 100 mass parts. Specifically, first, a water-insoluble binder which has been previously dispersed in water and water are prepared in a reaction vessel, and stirred under a nitrogen gas stream, thereby dispersing the dispersion A. The temperature of the dispersion A was raised to 70 ° C, and then a mixed solution of the monomers of the components (a) to (c) was added to the dispersion A, and 40 parts by mass of water and 1 part by mass of Newcol. 707SF were subjected to Stir This was pre-emulsified, and the pre-adjusted aqueous solution of the catalyst (0.1% aqueous ammonium persulfate solution) and the emulsified monomer were dropped into the reaction vessel in parallel at 80 ° C for about 3 hours, and continued at 80 ° C after the completion of the dropwise addition. Keep warm for about 1 hour. After cooling, 1.4 parts by mass of 25% ammonia water was added, and UH-420 was slowly added to adjust the viscosity to about 25,000 mPa ‧ s, and 0.35 parts by mass of Surflon S234 was added, whereby an aqueous adhesive composition was obtained.

(Example 4)

In Example 4, except that the monomer of the component (a) to the component (c) and the water-insoluble binder were used in the proportions shown in Table 1, 0.5 parts by mass of the amount of Newcol. 707SF and 0.5 parts by mass of KH were further used. The emulsion polymerization was carried out in the same manner as in Example 1 except for the amount of -1025.

(Comparative Example 5 and Comparative Example 6)

In Comparative Example 5 and Comparative Example 6, the monomer of the component (a) to the component (c) was mixed at a ratio shown in Table 1, and the rosin-based emulsifier for water-soluble emulsion polymerization was further added in the ratio shown in Table 1. The emulsion polymerization was carried out in the same manner as in Example 1 except that the rosin ester DRA-1500 containing ethylene oxide was dissolved in water to prepare a dispersion A in place of the water-insoluble binder.

(Comparative Example 7)

In Comparative Example 7, each raw material was used in the ratio shown in Table 1. Further, in addition to drying the water-insoluble adhesive at 100 ° C, it was further pulverized by a mortar, and then the powder of the water-insoluble adhesive was directly dissolved in the single component (a) to the component (c). The emulsion solution was carried out in the same manner as in Example 1 except that the mixed solution of the body was used instead of the dispersion A prepared by using the water-insoluble binder and water.

(Comparative Example 8)

In Comparative Example 8, each raw material was used in the ratio shown in Table 1. Further, the same procedure as in Comparative Example 7 was carried out except that the powder of the water-insoluble binder was not added to the emulsion polymerization, and then the powder of the water-insoluble binder was added before the coating.

In the examples 1 to 4, the comparative examples 1 to 4, the comparative examples 6, and the comparative examples 8, an aqueous adhesive composition was obtained. In Comparative Example 5 and Comparative Example 7, a large amount of aggregates were formed during the emulsion polymerization, and thus an aqueous adhesive composition could not be obtained.

*1: A water-insoluble binder is directly added to a mixture of monomers (however, it has not been emulsified). *2: After performing emulsion polymerization in a reaction containing no water-insoluble binder, a water-insoluble binder generator is added before coating.

The aqueous adhesive compositions obtained in Examples 1 to 4, Comparative Examples 1 to 4, Comparative Examples 6, and Comparative Examples 8 were evaluated as described in the following (3) to (10).

(3) Measurement of glass transfer point

The glass transition point is measured by the method according to JIS K7121. The results are shown in Table 1.

(4) Measurement of average particle diameter

The average particle diameter was measured by MICRO TRACK MT3000 (manufactured by NIKKISO CO., LTD.). The results are shown in Table 1.

(5) Measurement of tetrahydrofuran insoluble matter (THF insoluble matter)

The insoluble matter in the case where the copolymerization dispersion was dissolved in tetrahydrofuran was measured by adding 0.15 g of a dry film of an aqueous adhesive composition to 50 ml of tetrahydrofuran, and stirring and dissolving for 16 hours, and filtering the solution using two kinds of filter papers equivalent to JIS P3801. Thereafter, 10 ml of the filtrate was taken out and dried, and then an insoluble matter (gel fraction) was calculated from the mass after drying. The results are shown in Table 1 [Field of "THF insoluble matter (% by mass)" in Table 1].

(6) Test piece production

The aqueous adhesive composition was applied to a release paper (manufactured by LINTEC Corporation using an applicator and under the following conditions, On the separator EN78P), an adhesive layer was formed thereby and a test piece was produced.

Drying conditions: warm air dryer, 115 ° C × 90 seconds

Substrate: 50μm PET film

Curing: 40 ° C × 3 days

(7) Measurement of adhesion

The measurement of the adhesion was carried out by the method according to JIS Z 0237. The measurement conditions are as follows. The results are shown in Table 1.

Peel: 180° peeling (peeling speed 300mm/min)

Adhesive: SUS305 or polypropylene

Test piece width: 25mm

Pressing: Pressing on a 2kg roller on each of the adhesives under conditions of 23 ° C × 50% RH

Tensile test period: Tensile test after 1 day

(8) Measurement of retention force

A load of 500 g was hung in an environment of ‧65% RH at 40 ° C and the offset width was measured after 24 hours. When the offset width is 1 mm or less, the evaluation is "excellent", the offset width is more than 1 mm, and when it is 3 mm or less, it is evaluated as "good", and when the offset width exceeds 3 mm or when it is dropped, it is evaluated as "not". The results are shown in Table 1.

(9) Evaluation of water whitening resistance

The test piece was immersed in ion-exchanged water (23 ° C), and after 3 hours, the whitening of the adhesive layer of the test piece was visually observed. Unrecognized whitening or only a bluish but still transparent when evaluated as "excellent", can be identified as a little white, but still transparent when evaluated as "good", whitened or non-transparent The time is evaluated as "not". The results are shown in Table 1.

(10) Assessment of anchoring

When the zigzag test piece was repeated to adhere the adhesive faces to each other (self-adhesive) and the operation of peeling off the adhesive face, the number of times the adhesive layer was peeled off from the substrate was measured. The evaluation was "excellent" when it was 10 or more times, "good" when it was 5 to 9 times, and "not" when it was 4 times or less. The results are shown in Table 1.

The aqueous adhesive compositions of Examples 1 to 4 can obtain sufficient adhesion and anchoring properties, and have excellent water resistance.

With respect to the above, the aqueous adhesive compositions of Comparative Examples 1 to 8 are unsuitable aqueous adhesive compositions as described below.

From the viewpoint of not using a water-insoluble adhesive, Comparative Example 1 is an example other than the range defined by the present invention, and it was confirmed that the adhesive strength and the holding power were insufficient.

The comparative force 2 is an example in which the amount of the water-insoluble adhesive used exceeds the range defined by the present invention, and it is confirmed that the water resistance is insufficient.

Comparative Example 3 is an example in which the component (a) exceeds the range defined by the present invention, and has poor water resistance and adhesion to a polyolefin.

Comparative Example 4 is an example in which the THF insoluble matter exceeded the range defined by the present invention, and the anchoring property and the adhesion to the polyolefin were poor.

In the case of using the rosin-based emulsifier for water-soluble emulsion polymerization (rosine ester-added rosin ester DRA-1500), in place of the water-insoluble adhesive specified in the present invention, the comparative example 5 and the comparative example 6 were used. When the rosin-based emulsifier for water-soluble emulsion polymerization was not used in a large amount, it was confirmed that the aqueous adhesive composition could not be obtained. In addition, as shown in Comparative Example 6, even in When a water-based emulsifier for water-soluble emulsion polymerization (rosine ester-added rosin ester DRA-1500) was used in a large amount to obtain an aqueous adhesive composition, it was confirmed that the holding power and the water resistance were poor.

Comparative Example 7 was not subjected to seed polymerization. If the seed polymerization is not carried out, the aqueous adhesive composition cannot be obtained.

The mixing ratio of the raw materials of Comparative Example 8 was the same as in Example 3. When Comparative Example 8 and Example 3 were compared, after the emulsion polymerization was carried out without the water-insoluble binder contained in the reaction system, even if the water-insoluble adhesive was mixed (post-added) before coating, It was confirmed that the adhesion or retention or water whitening resistance was poor. That is, as in Example 3, it was confirmed that the adhesion polymerization, the holding power, and the water whitening resistance were improved by performing seed polymerization in the presence of a water-insoluble adhesive.

[Industrial Applicability]

The present invention can be utilized as an aqueous adhesive composition and a method for producing the same.

Claims (5)

An aqueous adhesive composition comprising: a copolymerization dispersion which is an emulsion polymerization polymerization of the following monomers in a reaction system containing 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm. The monomer includes: (a) 0.1 parts by mass to 10 parts by mass of the ethylenically unsaturated carboxylic acid monomer; and (b) 60 parts by mass of the acrylate monomer having an alkyl group having 4 to 12 carbon atoms. 99 parts by mass; and (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass), the particles of the copolymerized dispersion The average particle diameter is 0.3 μm to 10 μm, the glass transition point of the copolymerization dispersion is -70 ° C to -30 ° C, and the insoluble matter when the copolymerization dispersion is dissolved in tetrahydrofuran is 70% by mass or less. The aqueous adhesive composition according to claim 1, which contains a bridging agent. A method for producing a water-based adhesive composition, comprising: dispersing 0.1 to 10 parts by mass of a water-insoluble binder having an average particle diameter of 0.05 μm to 1.00 μm in a medium to form a dispersion in which the dispersion is formed Emulsification polymerization is carried out while adding the following monomers, thereby obtaining a copolymerization dispersion, wherein the monomer comprises: (a) an ethylenically unsaturated carboxylic acid monomer of 0.1 part by mass to 10% by mass (b) 60 parts by mass to 99 parts by mass of the acrylate monomer having an alkyl group having 4 to 12 carbon atoms; and (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) +(b)+(c)=100 parts by mass] The average particle diameter of the particles contained in the copolymerization dispersion is from 0.3 μm to 10 μm, and the glass transition point of the copolymerized dispersion is from -70 ° C to -30 ° C The insoluble matter when the copolymerization dispersion is dissolved in tetrahydrofuran is 70% by mass or less. A method for producing an aqueous adhesive composition, comprising: adding a water-insoluble adhesive having an average particle diameter of 0.05 μm to 1.00 μm to 0.1 mass to 10 mass in a pre-emulsion containing the following monomers, a medium, and an emulsifier; And carrying out emulsion polymerization, thereby obtaining a copolymerization dispersion, wherein the monomer comprises: (a) 0.1 parts by mass to 10 parts by mass of the ethylenically unsaturated carboxylic acid monomer; (b) the carbon number of the alkyl group is 4 60 parts by mass to 99 parts by mass of the acrylate monomer of ~12; (c) 0 parts by mass to 39.9 parts by mass of the ethylenically unsaturated monomer (wherein (a) + (b) + (c) = 100 parts by mass] The average particle diameter of the particles contained in the copolymerization dispersion is from 0.3 μm to 10 μm, and the glass transition point of the copolymerization dispersion is from -70 ° C to -30 ° C. The insoluble matter when the copolymerization dispersion is dissolved in tetrahydrofuran is 70% by mass or less. The method for producing an aqueous adhesive composition according to claim 3 or 4, which comprises adding a bridging agent to the copolymerized dispersion.