JPH11199847A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an emulsion type adhesive composition capable of exerting an excellent adhesive properties e.g. a good adhesive force as to various materials including porous materials, heat resistance and water resistance without any pretreatment e.g. sizing or primer coating, and additionally excellent in e.g. storage stability and workability. SOLUTION: This composition comprises the following components (a), (b) and (c), (a): a (co)polymer emulsion obtained by polymerizing a vinyl ester monomer only or copolymerizing a vinyl ester monomer with a monomer copolymerizable with the vinyl ester monomer; (b): an inorganic filler comprising >=50% of calcium carbonate; and (c): a compound allowed for chelation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an emulsion-type adhesive composition.

[0002]

2. Description of the Related Art Conventionally, plastic material sheets such as hard or semi-hard vinyl chloride resin, polyolefin resin, polyester resin, etc., veneer obtained by processing wood into sheet form, decorative paper on which various decorative printings are applied, etc. Of so-called surface decorative sheets, lauan plywood, medium fiberboard (MD
F), a so-called surface decorative board which is adhered to the surface of a base material made of a woody material such as particle board, solid wood or the like, or a cement board, a gypsum board, an inorganic material such as ALC or the like to give a design property is a building member or a furniture member. Widely used as etc.

[0003] The adhesion between the surface decorative sheet and the substrate is as follows.
BACKGROUND ART Adhesive compositions containing a vinyl acetate resin emulsion as a main component, such as a vinyl acetate resin emulsion, an ethylene-vinyl acetate copolymer emulsion, and an acrylate-vinyl acetate copolymer emulsion, are widely used.

Many of the above-mentioned surface decorative sheets, substrates made of woody materials, inorganic materials and the like are porous materials. However, when an emulsion type adhesive composition such as a vinyl acetate resin emulsion is used, the porous material becomes Since water, which is a medium of the emulsion-type adhesive composition, permeates and the adhesive strength after bonding quickly rises, there is an advantage that the initial adhesive strength is excellent.

However, since the porous material has many irregularities on its surface, a phenomenon in which the bonding is performed only at the convex portion, that is, a so-called “point bonding state” tends to occur, and a sufficient bonding strength can be obtained. There is a problem that sometimes there is not.

In the case of an emulsion type adhesive composition,
Since the adhesive strength rises through the process of water diffusion, volume contraction inevitably occurs in this process. for that reason,
Depending on the type of surface decorative sheet, the uneven shape of the base material will remain on the surface of the surface decorative sheet after bonding as it is,
There is also a problem that the appearance quality of the surface decorative plate obtained may be impaired.

As a method for solving the above-mentioned problems, a method of preliminarily filling the surface of the base material or applying a primer (primer) may be used. The method is not a practically preferable method because the production process becomes complicated and the productivity is reduced.

As another method for solving the above-mentioned problem, a method of increasing the sealing effect of a porous material by adding an inorganic filler to an emulsion-type adhesive composition has also been performed. I have.

For example, Japanese Patent Application Laid-Open No. 5-339550 discloses that a copolymer of an α-olefin and maleic anhydride and / or maleic anhydride or a neutralized product thereof is used as a protective colloid to form vinyl acetate or vinyl acetate. And 100 to 100 parts by weight of a resin component of a synthetic resin emulsion obtained by emulsion polymerization of a mixture of and another unsaturated monomer, the inorganic filler is 50 to 200 parts by weight, an aliphatic hydrocarbon or an aromatic hydrocarbon or An adhesive composition for wooden flooring, characterized in that a compound represented by a specific chemical structural formula is contained in a proportion of 1 to 10 parts by weight.

However, the adhesive composition proposed above is
It does not simultaneously satisfy the workability such as viscosity, storage stability, mechanical stability at the time of application with a roll, etc. and the adhesive performance such as adhesive strength, heat resistance, water resistance, etc. It is hard to say that it has.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention is applicable to various adherends such as porous materials without performing pretreatment such as sealing or primer application. It is an object of the present invention to provide an emulsion-type adhesive composition which exhibits excellent adhesive strength such as excellent adhesive strength, excellent heat resistance and water resistance, and is excellent in storage stability, workability and the like.

[0012]

The adhesive composition according to the invention described in claim 1 (hereinafter referred to as "first invention")
It is characterized by containing the following components (a1), (b) and (c). (A1) Component: (co) polymer emulsion obtained by emulsifying (co) polymerizing a vinyl ester monomer alone or a vinyl ester monomer and a monomer copolymerizable with the vinyl ester monomer (b) Component: 50 parts of calcium carbonate Inorganic filler containing not less than 10% by weight (c) Component: a compound capable of forming a chelate ring

The invention according to claim 2 (hereinafter referred to as “second
The adhesive composition according to the present invention is characterized by comprising the following components (a2), (b), (c) and (d). (A2) component: ethylene-vinyl acetate copolymer emulsion (b) component: an inorganic filler containing 50% by weight or more of calcium carbonate (c) component: a compound capable of forming a chelate ring (d) component: anionic Urethane resin emulsion

Further, the invention according to claim 3 (hereinafter referred to as "the invention")
The adhesive composition according to the “third invention” is the first adhesive composition.
The adhesive composition according to the invention or the second invention is further characterized in that, as the component (e), a compound having two or more functional groups capable of reacting with an active hydrogen atom in the molecule is contained.

Furthermore, the invention according to claim 4 (hereinafter referred to as "the invention")
The adhesive composition according to the "fourth invention") is the first adhesive composition.
The adhesive composition according to any one of the inventions to the third invention, wherein the component (c) is ethylenediaminetetraacetic acid.

The adhesive composition according to the first invention comprises (a1
The component ()) includes a (co) polymer emulsion obtained by emulsifying (co) polymerizing a vinyl ester monomer alone or a vinyl ester monomer and a monomer copolymerizable with the vinyl ester monomer. Here, “(co) polymerization” means “polymerization” or “copolymerization”.

The vinyl ester monomer is not particularly restricted but includes, for example, vinyl acetate, vinyl propionate, vinyl pivalate, vinyl isononanoate, vinyl versatate and the like.
The species or two or more species are preferably used, and among them, vinyl acetate having a good balance between performance and cost is more preferably used.

As the monomer copolymerizable with the vinyl ester monomer, a known monomer having a polymerizable double bond is suitably used, and it is not particularly limited. For example, (meth) acrylic acid , Methyl (meth)
Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol (meth) acrylate, glycidyl (meth) acrylate , 2-hydroxyethyl (meth)
Acrylic monomers such as acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate; ethylene, propylene, styrene, butadiene, acrylonitrile, vinyl chloride, chloroprene, isoprene, and a third having an average carbon number of 10 Monomers such as graded vinyl carboxylate and the like are mentioned, and one or two or more of these are suitably used. Here, “(meth) acryl” means “acryl” or “methacryl”.

The method for producing the (co) polymer emulsion contained as the component (a1) in the adhesive composition according to the first invention is not particularly limited, and examples thereof include polyvinyl alcohol (PVA) and carboxyl group-modified PVA. Using such a modified PVA or the like as a protective colloid, the vinyl ester monomer alone or the above-mentioned monomer copolymerizable with the vinyl ester monomer may be subjected to emulsion (co) polymerization in the presence of a polymerization catalyst by a conventional method.

The PVA or modified PVA used as a protective colloid is not particularly limited, but preferably has an average degree of saponification of 70 to 99.5 mol%, and has an average degree of polymerization of 200 to 3000. Is preferred. If necessary, an emulsifying and dispersing agent such as a surfactant or a cellulose derivative may be used in combination with the PVA or the modified PVA.

The polymerization catalyst used in the emulsion (co) polymerization is not particularly limited, but examples thereof include aqueous hydrogen peroxide, persulfates such as ammonium persulfate, potassium persulfate and sodium persulfate, tartaric acid, Examples thereof include reducing agents such as formic acid and oxalic acid, and one or more of these are suitably used.

The adhesive composition according to the first invention includes (b)
As a component, an inorganic filler containing 50% by weight or more of calcium carbonate is contained.

When the adhesive composition contains an inorganic filler containing 50% by weight or more of calcium carbonate as the component (b), the adhesive performance of the obtained adhesive composition to a porous material is remarkable. improves.

The type of the calcium carbonate is not particularly limited, and includes, for example, conventionally known calcium carbonates such as heavy calcium carbonate, colloidal light calcium carbonate, surface-treated fine calcium carbonate and the like. One or more kinds are suitably used.

Further, other inorganic fillers that can be used in combination with calcium carbonate are not particularly limited.
For example, conventionally known silica-based fillers such as talc, clay, mica powder, silica sand and the like can be mentioned.
More than one species is preferably used.

In the first invention, the inorganic filler used as the component (b) must be an inorganic filler containing 50% by weight or more of calcium carbonate.

When the content of calcium carbonate in the inorganic filler is less than 50% by weight, in other words, when the content of the inorganic filler other than calcium carbonate is 50% by weight or more, the resulting adhesive is obtained. The viscosity and the structural viscosity of the composition become too high, and the storage stability and the mechanical stability deteriorate.

The content of the inorganic filler as the component (b) in the adhesive composition is not particularly limited, but the solid content of the (co) polymer emulsion as the component (a1) is not limited. 100 parts by weight of inorganic filler 1
It is preferably 0 to 300 parts by weight, and preferably 20 to 150 parts by weight.
More preferably, it is part by weight.

When the content of the inorganic filler as the component (b) is less than 10 parts by weight based on 100 parts by weight of the solid content of the (co) polymer emulsion as the component (a1), the resulting adhesive composition is obtained. When the content of the inorganic filler exceeds 300 parts by weight based on 100 parts by weight of the solid content of the (co) polymer emulsion, the effect may not be sufficiently obtained. Since the viscosity and structural viscosity of the adhesive composition to be used are too high, storage stability and mechanical stability are reduced, and the ratio of the resin component in the adhesive composition is relatively small, In some cases, the development of strength may be delayed, or the bonding strength may be reduced.

The adhesive composition according to the first invention comprises (c)
As a component, a compound capable of forming a chelate ring is contained.

By incorporating a compound capable of forming a chelate ring as the component (c) into the adhesive composition,
The change in viscosity of the obtained adhesive composition is reduced, and the storage stability is significantly improved.

The compound capable of forming a chelate ring is
It means a compound having a molecular structure capable of forming a chelate ring. The chelate ring referred to herein is a ring structure formed by two or more coordinating atoms of one molecule sandwiching a metal atom or an ion, and the metal atom or the ion and the (c) component Can capture metal atoms or ions by a stable structure formed between the compound and a compound capable of forming a chelate ring.

The compound capable of forming the above-mentioned chelate ring is not particularly limited. For example, oxalic acid, ethylenediamine, trimethylenediamine, dimethylglyoxime, dithizone, oxine, acetylacetone, glycine, ethylenediaminetetraacetic acid (EDTA) ), Nitrilotriacetic acid (NTA), various crown ethers, and derivatives thereof, and one or more of these are suitably used.

When the compound capable of forming a chelate ring is a compound having a functional group capable of forming a salt such as a carboxyl group, the compound may be in the form of a metal salt such as a sodium salt or a potassium salt. Is also good.

Among the various compounds capable of forming a chelate ring, one or more of acetylacetone, ethylenediaminetetraacetic acid (EDTA), and metal salts thereof are more preferably used.

The content of the compound capable of forming the chelate ring as the component (c) in the adhesive composition is not particularly limited, but the (co) polymer emulsion as the component (a1) is not limited. Is preferably 0.05 to 5 parts by weight of a compound capable of forming a chelate ring with respect to 100 parts by weight of the solid content of the above.

If the content of the compound capable of forming a chelate ring as the component (c) is less than 0.05 part by weight per 100 parts by weight of the solid content of the (co) polymer emulsion as the component (a1), The effect of improving the storage stability of the resulting adhesive composition may be insufficient, and conversely, the content of the compound capable of forming a chelate ring with respect to 100 parts by weight of the solid content of the (co) polymer emulsion is 5 parts by weight. If exceeded,
In some cases, the dispersibility of the (co) polymer emulsion itself is impaired, causing aggregation of the particles, resulting in reduced storage stability.

Next, the adhesive composition according to the second invention includes:
As the component (a2), an ethylene-vinyl acetate copolymer emulsion is contained.

The ethylene-vinyl acetate copolymer emulsion as the component (a2) is obtained by emulsion-copolymerizing a vinyl acetate monomer and ethylene under pressure by a conventional method.

The ethylene content in the above-mentioned ethylene-vinyl acetate copolymer is not particularly limited.
It is preferably 40% by weight, more preferably 10 to 25% by weight.

When the ethylene content in the ethylene-vinyl acetate copolymer is less than 5% by weight, the film forming temperature of the obtained adhesive composition is increased, and the film forming property and low-temperature adhesiveness are reduced. Conversely, if the ethylene content exceeds 40% by weight, the adhesiveness of the resulting adhesive composition to various adherends and the heat resistance may decrease.

The above-mentioned ethylene-vinyl acetate copolymer emulsion is not limited to a binary copolymer emulsion of vinyl acetate and ethylene, but may be a monomer copolymerizable with vinyl acetate, ethylene and the above-mentioned vinyl ester monomer. A ternary or higher copolymer emulsion obtained by copolymerizing one or more of monomers having a polymerizable double bond as exemplified above may be used.

The adhesive composition according to the second invention comprises (a2
In addition to the ethylene-vinyl acetate copolymer emulsion as the component, the inorganic filler containing 50% by weight or more of the calcium carbonate as the component (b), and the compound capable of forming a chelate ring as the component (c), Further, an anionic urethane resin emulsion is contained as the component (d).

By including an anionic urethane resin emulsion as the component (d) in the adhesive composition, the adhesive properties of the obtained adhesive composition such as adhesiveness, heat resistance and water resistance are remarkably improved.

The anionic urethane resin emulsion includes, but is not limited to, for example, a reaction product of a polyol compound and a polyisocyanate compound, and a functional group having at least one active hydrogen in the molecule. In addition, a polyurethane resin synthesized by reacting with a functional compound having an acid group can be obtained by dispersing in water and emulsifying.

As the polyol compound used for synthesizing the above polyurethane resin, a compound having two or more hydroxyl groups in a molecule is suitably used, and is not particularly limited. Examples thereof include ethylene glycol, diethylene glycol, and propylene. Polyhydric alcohols such as glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, trimethylolpropane and glycerin; polyether polyols such as polyethylene glycol, polypropylene glycol and polytetramethylene ether glycol; Dicarboxylic acids such as adipic acid, sebacic acid, itaconic acid, maleic anhydride, terephthalic acid, isophthalic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, etc. Glycol, diethylene glycol, propylene glycol, 1,4-butanediol,
1,6-hexanediol, neopentyl glycol,
Reaction with polyol compounds such as 1,2-propanediol, 1,3-propanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, tripropylene glycol, trimethylolpropane, and glycerin Polyester polyols obtained; polylactone-based polyester polyols such as polycaprolactone polyol and poly-β-methyl-δ-valerolactone; polybutadiene polyol or its hydrogenated product, polycarbonate polyol, polythioether polyol, polyacrylate polyol and the like. And
One or more of these are preferably used.

The molecular weight of the above-mentioned polyol compound is not particularly limited, but the number average molecular weight is 1,000 to 5
000 is preferred. If the number average molecular weight of the polyol compound is less than 1,000, the resulting dried film of the anionic urethane resin emulsion becomes too hard, and the initial adhesive strength of the adhesive composition may be reduced,
Conversely, if it exceeds 5,000, the resulting dried film of the anionic urethane resin emulsion becomes too soft, and the heat resistance of the adhesive composition may be reduced.

As the polyisocyanate compound used for synthesizing the polyurethane resin, an organic polyisocyanate compound having two or more isocyanate groups in a molecule is suitably used, and is not particularly limited. 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,
4,4-trimethylhexamethylene diisocyanate,
2,2,4-trimethylhexamethylene diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, dicyclohexylmethane-4,4′-diisocyanate, methylcyclohexyl-2,4-diisocyanate, methylcyclohexyl-2, 6-diisocyanate, xylylenediisocyanate, 1,3-bis (isocyanate) methylcyclohexane, tetramethylxylylenediisocyanate,
Transcyclohexane-1,4-diisocyanate,
Aliphatic diisocyanate compounds such as lysine diisocyanate; 2,4-toluylene diisocyanate, 2,6-
Toluylene diisocyanate, diphenylmethane-4,
Aromatic diisocyanate compounds such as 4'-diisocyanate, 1,5'-naphthene diisocyanate, tolidine diisocyanate, diphenylmethylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,3-phenylenediisocyanate; lysine ester Triisocyanate, triphenylmethane triisocyanate, 1,6,11-undecane triisocyanate,
1,8-isocyanate-4,4-isocyanatomethyloctane, 1,3,6-hexamethylenetriisocyanate, bicycloheptanetriisocyanate, adduct of trimethylolpropane and 2,4-toluylenediisocyanate, trimethylolpropane 1,6-
Examples thereof include triisocyanate compounds such as an adduct with hexamethylene diisocyanate, and one or more of these are suitably used.

Further, as the functional compound having at least one active hydrogen in the molecule used for synthesizing the polyurethane resin and having an acid group, the functional compound having a hydroxyl group or a primary amino group in the molecule may be used. Alternatively, a functional compound containing a functional group having at least one active hydrogen capable of reacting with an isocyanate group such as a secondary amino group and containing an acid group such as a carboxylic acid group or a sulfonic acid group ( Hereinafter, simply referred to as “functional compound”) are suitably used and are not particularly limited. For example, 3,4-diaminobutanesulfonic acid, 3,6-diamino-2-toluenesulfonic acid, , 6-Diaminobenzenesulfonic acid, N-
Sulfonic acid group-containing compounds such as (2-aminoethyl) -2-aminoethylsulfonic acid; carboxylic acid group-containing compounds such as 2,2-dimethylol lactic acid, 2,2-dimethylol propionic acid, and 2,2-dimethylol valeric acid Compounds and the like are mentioned, and one or more of these are suitably used.

Since the above-mentioned functional compound contains an acid group, an acid group as a hydrophilic group is introduced into the obtained polyurethane resin, thereby exhibiting an effect of improving the stability when the polyurethane resin is dispersed in water. I do.

The polyurethane resin having an acid group introduced into the molecule is called an ionomer structure. The polyurethane resin itself has surfactant activity and has excellent self-emulsifying properties. It can be stably dispersed in water without using a molecular hydrophilic compound. Therefore, an adhesive composition containing an anionic urethane resin emulsion obtained by emulsifying the polyurethane resin has excellent water resistance.

In order to further improve the surface activity of the polyurethane resin, an acid group such as a carboxylic acid group or a sulfonic acid group is usually neutralized with a neutralizing agent to form a carboxylic acid group or a sulfonic acid group. It is preferably used in the form of an acid base such as

The neutralizing agent is not particularly restricted but includes, for example, tertiary amine compounds such as triethylamine and triethanolamine and inorganic alkali compounds such as potassium hydroxide and sodium hydroxide. One or more of these are preferably used.

As another method for imparting hydrophilicity to the polyurethane resin, a method using a nonionic hydrophilic compound such as polyethylene glycol may be used in addition to the above-mentioned method for introducing an acid group.

For example, as a raw material when synthesizing a polyurethane resin, a functional group such as a hydroxyl group having at least one active hydrogen capable of reacting with an isocyanate group, a primary amino group or a secondary amino group is contained in a molecule. The above method is achieved by using a compound having a polyethylene glycol skeleton.

However, since the urethane resin emulsion contained in the adhesive composition according to the second invention needs to be anionic, a method for imparting hydrophilicity to the polyurethane resin is to introduce the acid group. It is necessary to employ any one of a method, a method of introducing an acid group, and a method of using the above-mentioned method using a nonionic compound in combination.

As a raw material for synthesizing the polyurethane resin, various active hydrogen-containing compounds may be used for the purpose of chain elongation, molecular weight control, etc., if necessary, as long as the object of the present invention is not hindered. Is also good.

The active hydrogen-containing compound is not particularly restricted but includes, for example, ethylenediamine,
Polyhydric amines such as 1,4-butanediamine and 1,6-hexanediamine; tertiary amine-containing polyhydric alcohols such as triethanolamine; monoalcohols such as methanol, ethanol and butanol; Of 1
Species or two or more species are suitably used.

Since the polyurethane resin obtained by the above-mentioned method has excellent self-emulsifying properties, it is possible to use an acetone method, a prepolymer mixing method, a ketimine method, a hot melt dispersion method or the like without using an emulsifier or a surfactant. A stable anionic urethane resin emulsion can be obtained by the method known in the art.

The solid content of the thus obtained anionic urethane resin emulsion is not particularly limited, but is preferably 30 to 70% by weight, and is preferably 40 to 6% by weight.
More preferably, it is 0% by weight.

The content of the anionic urethane resin emulsion as the component (d) in the adhesive composition according to the second invention is not particularly limited.
The solid content of the anionic urethane resin emulsion is preferably 3 to 150 parts by weight based on 100 parts by weight of the solid content of the ethylene-vinyl acetate copolymer emulsion as the component (a2).

When the content of the solid content of the anionic urethane resin emulsion as the component (d) is less than 3 parts by weight per 100 parts by weight of the solid content of the ethylene-vinyl acetate copolymer emulsion as the component (a2), In some cases, the effect of improving the adhesive performance by containing the anionic urethane resin emulsion may not be sufficiently obtained, and conversely, the solid content of the ethylene-vinyl acetate copolymer emulsion may be 10%.
If the content of the solid content of the anionic urethane resin emulsion with respect to 0 parts by weight exceeds 150 parts by weight, the cost is increased and the practicability may be poor.

Next, the adhesive composition according to the third invention is different from the adhesive composition according to the first invention or the second invention in that (a)
1) In addition to the component, component (b) and component (c) (first invention), or (a2) component, component (b), component (c) and component (d) other than component (second invention), Further, the component (e) must contain a compound having two or more functional groups capable of reacting with an active hydrogen atom in the molecule.

The compound having two or more functional groups capable of reacting with an active hydrogen atom in the molecule as the component (e) has a function as a curing agent, and has an adhesive strength and heat resistance of the obtained adhesive composition. Adhesive performance such as water resistance and water resistance is remarkably improved.

The compound having two or more functional groups capable of reacting with an active hydrogen atom in the molecule (hereinafter referred to as “curing agent”) is not particularly limited. And conventionally known curing agents such as melamine-based curing agents, aziridine-based curing agents, epoxy-based curing agents, oxazoline-based curing agents, and carbodiimide-based curing agents. One or more of these are suitably used. One or more of isocyanate-based curing agents, epoxy-based curing agents, carbodiimide-based curing agents, etc.
More than one species is more preferably used.

The isocyanate-based curing agent is not particularly limited as long as it is a compound having two or more isocyanate groups in a molecule. Examples thereof include tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). , A diisocyanate compound such as hexamethylene diisocyanate (HDI), a polyisocyanate compound which is a dimer, a trimer, or a multimer thereof, or a modified polyisocyanate compound which is a modified product thereof. One or more of these are preferably used. Among them, a water-dispersible modified polyisocyanate compound obtained by modifying a polyisocyanate compound with a nonionic hydrophilic compound such as, for example, polyethylene glycol Of 1
The species or two or more species are more preferably used as a so-called “aqueous curing agent”.

The epoxy-based curing agent is not particularly limited as long as it is a compound having two or more epoxy groups in a molecule. Examples thereof include a bisphenol-type epoxy compound and a phenol novolak-type epoxy compound. N, N, N ', N'-tetraglycidyl-m
An epoxy curing agent having no water solubility or strong hydrophilicity per se, such as an epoxy compound containing a tertiary amine such as xylylenediamine; a water-soluble epoxy curing agent modified with a hydrophilic segment; bisphenol Water-dispersed epoxy hardeners in which an epoxy compound of the type or a phenol novolak type epoxy compound is forcibly dispersed in water with an emulsifier, and one or more of these are suitably used. One or more water-soluble epoxy curing agents are more preferably used.

The water-soluble epoxy curing agent is not particularly restricted but includes, for example, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol diglycidyl ether. , Glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, polyglycerol polyglycidyl ether pentaerythritol polyglycidyl ether, and the like.
One or more of these are preferably used.

The carbodiimide-based curing agent is not particularly limited, but may be, for example, a compound represented by the general formula R ¹ -N = C
= N—R ^2, wherein R ¹ and / or R ² is hydrogen, a propyl group, a cyclohexyl group or a p-toluoyl group; and the like, and one or more of these are preferably used. Can be

The carbodiimide-based curing agent is preferably one imparted with hydrophilicity by denaturation, and is preferably added to the adhesive composition in a state diluted with water or a hydrophilic organic solvent.

The content of the compound (curing agent) having two or more functional groups capable of reacting with an active hydrogen atom in the molecule as the component (e) in the adhesive composition according to the third invention is as follows:
Although not particularly limited, the solid content of the (co) polymer emulsion (first invention) as the component (a1) or the ethylene-vinyl acetate copolymer emulsion (second invention) as the component (a2) is 100%. The curing agent preferably has a solid content of 0.3 to 30 parts by weight, and
More preferably, the amount is from 10 to 10 parts by weight.

Solid content 1 of component (a1) or component (a2)
When the content of the solid content of the curing agent as the component (e) is less than 0.3 part by weight with respect to 00 parts by weight, the effect of improving the adhesive performance by containing the curing agent may not be sufficiently obtained, Conversely, if the content of the solid content of the curing agent with respect to 100 parts by weight of the solid content of the component (a1) or the component (a2) exceeds 30% by weight, the storage stability of the obtained adhesive composition may decrease. .

Next, the adhesive composition according to the fourth aspect of the present invention is the adhesive composition according to any one of the first to third aspects described above, wherein the compound capable of forming a chelate ring as the component (c) is ethylenediamine. It must be tetraacetic acid (EDTA).

By including ethylenediaminetetraacetic acid (EDTA) as the component (c), the storage stability of the obtained adhesive composition is further improved.

The adhesive compositions according to the first to fourth aspects of the present invention may contain, if necessary, an organic solvent for adjusting the viscosity or improving the film forming property, or adjusting the viscosity or shaking, as long as the achievement of the object of the present invention is not hindered. Thickeners or thixotropic agents for modification control, adhesion improvers, tackifiers, plasticizers, softeners, surfactants, emulsifiers, colorants, fungicides, preservatives, rust inhibitors, One or more of various additives such as an antifoaming agent may be contained.

The organic solvent is not particularly restricted but includes, for example, toluene, xylene, cyclohexane, n-hexane, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate and the like. Alternatively, two or more types are suitably used.

The amount of the organic solvent to be added is not particularly limited, but is preferably 2 to 20 parts by weight of the organic solvent based on 100 parts by weight of the solid content of the adhesive composition.

If the amount of the organic solvent is less than 2 parts by weight per 100 parts by weight of the solid content of the adhesive composition, the effect of adjusting the viscosity and the effect of improving the film forming property may not be sufficiently obtained,
Conversely, if the amount of the organic solvent exceeds 20 parts by weight, the organic solvent may be separated during storage, and there is a risk of fire and environmental pollution, which is not preferable.

The thickening agent or thixotropic agent is not particularly limited. For example, a urethane-based nonionic thickening agent or thixotropic agent, or an alkali thickening type anionic thickening agent. Conventionally known thickeners or thixotropic agents such as tackifiers or thixotropic agents, various water-soluble polymers, and the like can be mentioned, and one or more of these are suitably used.

The method for producing the adhesive composition according to the first to fourth inventions is not particularly limited. For example, a known mixer such as a universal mixer, a homomixer, a homodisper, a dissolver, a Satake-type mixer, or the like can be used. And a predetermined amount of each component may be uniformly stirred and mixed.

In the above manufacturing method, in the case of the first invention,
While stirring the (co) polymer emulsion as the (a1) component, 50% by weight of calcium carbonate as the (b) component was added.
It is preferable to gradually add and mix the inorganic filler contained above. The inorganic filler as the component (b) may be added as it is, but in order to further improve the dispersibility, a master batch prepared by kneading the inorganic filler and a small amount of water in advance is used. Alternatively, it is preferable to add a slurry prepared by dispersing an inorganic filler in a small amount of water in advance.

In the case of the second invention, the ethylene-vinyl acetate copolymer emulsion as the component (a2) exhibits acidity and the anionic urethane resin emulsion as the component (d) exhibits alkalinity. ) Component p
After adjusting H to neutral or alkaline, it is preferable to mix both.

The pH adjustment of the above component (a2) is performed by adjusting the component (a2)
The stirring can be performed by adding an appropriate amount of aqueous ammonia, an organic amine compound such as triethanolamine or triethylamine, or an inorganic base such as sodium chloride or sodium bicarbonate while stirring the ethylene-vinyl acetate copolymer emulsion as a component. .

Further, in the case of the third invention, the addition of a compound (curing agent) having two or more functional groups capable of reacting with an active hydrogen atom in the molecule as the component (e) may be the last of each component. preferable.

The viscosity of the adhesive composition according to the first to fourth inventions may be appropriately set according to the application and the application method, and is not particularly limited. 8000 to 80000 cp at 20 ° C
s, preferably 12000 to 60000 cp
More preferably, s.

The viscosity of the adhesive composition at 20 ° C. is 80.
When the viscosity is less than 00 cps, the adhesive composition becomes too easy to flow, so that the adhesive composition may flow out of the applicator at the time of application by a roll and workability may be reduced.
If the viscosity at 0 ° C. exceeds 80000 cps, the fluidity of the adhesive composition becomes poor, so that it may be difficult to supply the adhesive composition to a coating machine or apply a roll with a uniform coating amount.

In the case of applying with a comb-like iron, for example, it is preferable to set the viscosity higher than the above viscosity. For example, when applying with a spray or a flow coater,
It is preferable to set the viscosity lower than the above viscosity.

The solid content of the adhesive composition according to the first to fourth inventions is not particularly limited, but is generally preferably from 30 to 70% by weight, and more preferably from 40 to 60% by weight. More preferably, there is.

If the solids content of the adhesive composition is less than 30% by weight, the moisture content becomes too large, so that a large amount of time and energy is required for drying after coating, resulting in reduced workability and cost. May be high. In addition, it may be disadvantageous in terms of transportation cost.

Conversely, if the solids content of the adhesive composition exceeds 70% by weight, the content of the resin component in the adhesive composition becomes too large, so that the storage stability and mechanical stability are reduced. There is.

The adhesive compositions according to the first to fourth inventions are suitably used mainly for building materials, decorative plywood, woodworking and the like, but are not limited to these uses, and are not limited to paper processing, fiber Needless to say, it may be used for processing, general use, and the like.

[0092]

The adhesive composition according to the first invention comprises a (co) polymer emulsion obtained by emulsifying (co) polymerizing a vinyl ester monomer alone or a vinyl ester monomer and a monomer copolymerizable with the vinyl ester monomer. Excellent adhesion to various adherends, including porous materials, as an inorganic filler containing 50% by weight or more of calcium carbonate as a main component and a compound capable of forming a chelate ring. In addition to exhibiting excellent adhesive properties such as heat resistance and water resistance, it also has excellent storage stability and workability.

The adhesive composition according to the second invention comprises an ethylene-vinyl acetate copolymer emulsion, an inorganic filler containing 50% by weight or more of calcium carbonate, and a compound capable of forming a chelate ring. Since the urethane resin emulsion is contained, adhesion to various adherends such as a porous material, heat resistance, and water resistance are improved.

Further, the adhesive composition according to the third invention comprises:
In the adhesive composition according to the first or second invention, a compound having two or more functional groups capable of reacting with an active hydrogen atom in a molecule is contained as a curing agent. The cohesive force of the material is moderately improved, and the adhesive strength and heat resistance to various adherends including porous materials,
Adhesion performance such as water resistance is further improved.

Further, in the adhesive composition according to the fourth invention, ethylenediaminetetraacetic acid (EDTA) is used as the compound capable of forming a chelate ring in the adhesive composition according to any one of the first invention to the third invention. Therefore, it has a much better storage stability.

[0096]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, “parts” means “parts by weight”, and “%” means “% by weight” unless otherwise specified.

(Example 1)

(1) Polymerization of Vinyl Acetate Resin Emulsion In a reaction vessel equipped with a stirrer, reflux condenser, thermometer and dropping funnel, 111 parts of water and polyvinyl alcohol (trade name “Kuraray PVA-CST”, average degree of saponification of 96) were added. (Mol%, average polymerization degree: 1700, manufactured by Kuraray Co., Ltd.), and heated at 90 ° C. for 1 hour with stirring to obtain an aqueous solution of polyvinyl alcohol. Next, the aqueous solution is cooled to 70 ° C.
To this, 8 parts of a vinyl acetate monomer and 0.2 parts of a polymerization catalyst (0.1 part of a hydrogen peroxide solution and 0.1 part of tartaric acid) were added to cause initial polymerization. Then, vinyl acetate monomer 9
2 parts and 0.8 parts of a polymerization catalyst (0.4 parts of hydrogen peroxide and 0.4 parts of tartaric acid) were added dropwise over 3 hours, emulsion polymerization was performed at 70 ° C., and the mixture was aged at 90 ° C. for 1 hour. And a solid content of 50
% Vinyl acetate resin emulsion was obtained.

(2) Preparation of Adhesive Composition To 100 parts of the vinyl acetate resin emulsion obtained above, dioctyl phthalate (DOP) 7 was used as a plasticizer.
Part, trade name “ViscalexAT-7” as a thickener
7 "(Allied Colloids Limite
d) 5.1 parts of a dispersion obtained by sufficiently dispersing 0.1 part of toluene in 5 parts of toluene was added and uniformly stirred and mixed. Next, heavy calcium carbonate (trade name “Calcium carbonate first grade”) was used as an inorganic filler while stirring 112.1 parts of the emulsion containing the plasticizer, the thickener, and toluene obtained above with a homodisper. (Manufactured by Sankyo Seiko Co., Ltd.) was gradually added. Stirring was continued for 30 minutes even after the entire amount of the heavy calcium carbonate was added, and the heavy calcium carbonate was uniformly mixed in the emulsion. Then, as a compound capable of forming a chelate ring, ethylenediaminetetraacetic acid (ED
TA) 1.32 parts of ammonia water (2.5%) 2.68
4 parts of the dispersion liquid sufficiently dispersed in the mixture was added and uniformly stirred and mixed to obtain an adhesive composition having a solid content of 58%.

(3) Evaluation The performance of the adhesive composition obtained above (normal adhesive strength,
Heat creep resistance and storage stability) were evaluated by the following methods. The results were as shown in Table 1.

Normal Adhesive Strength The adhesive composition was uniformly applied to a 2.5 mm-thick softwood plywood using a rubber roller so that the application amount was 100 g / m ² . Then, immediately after, the back surface of a semi-rigid vinyl chloride decorative sheet having a thickness of 0.2 mm, the surface of which is printed with woodgrain, is stuck, and the pressure: 40 kg / m ² , temperature:
Room temperature, time: Pressing was performed under pressing conditions of 24 hours. further,
After pressing and releasing, the cured product was left to stand at room temperature for one week for curing to obtain a vinyl chloride decorative plywood.

The obtained vinyl chloride decorative plywood is 25 mm wide.
Into a test piece for measurement, and using a Tensilon-type tensile tester at a peeling speed of 200 mm / min.
An 80-degree peel test was conducted to determine the normal adhesive strength (Kg / 25
mm). The measurement was performed in an atmosphere of 20 ° C. and 65% RH.

Heat Creep Resistance The vinyl chloride decorative plywood obtained above was cut into a width of 25 mm and a length of 150 mm to prepare a test piece for measurement. next,
Put the semi-rigid vinyl chloride decorative sheet side 5 mm from the end in the vertical direction.
The test piece was peeled by 0 mm, and the test piece was placed horizontally in a blast drying oven at 60 ° C. for 1 hour while the peeled decorative sheet was hung. Next, in the same oven, a 500 g static load was applied to the tip of the hanging decorative sheet, and the sheet was allowed to stand for 1 hour, and the peeling progress length (mm) after 1 hour was measured. In this case, the shorter the length of the peeling, the better the heat creep resistance.

Storage stability Using a BH type rotational viscometer, at a rotation speed of 10 rpm,
The initial viscosity (cps, 20 ° C.) of the adhesive composition was measured. Next, the adhesive composition was placed in a sealed container, and
After standing for one week in an atmosphere of 0 ° C., the viscosity (cps, 20 ° C.) after aging was measured under the same conditions. By evaluating the degree of the viscosity change at this time, the storage stability was promoted.

Example 2 In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer and a dropping funnel, 134 parts of water and 10 parts of "Kuraray PVA-CST" were charged and stirred while stirring.
Heating at 0 ° C. for 1 hour gave an aqueous solution of polyvinyl alcohol. Next, this aqueous solution was cooled to 75 ° C., and a vinyl acetate monomer / butyl acrylate monomer =
10 parts of a 7/3 (weight ratio) mixed monomer and 0.1 part of a polymerization catalyst (0.06 part of hydrogen peroxide and 0.04 part of tartaric acid)
Parts) was charged to perform initial polymerization. Next, 90 parts of the mixed monomer and 0.4 part of a polymerization catalyst (0.24 part of hydrogen peroxide solution and 0.16 part of tartaric acid) were added dropwise over 3 hours, and emulsion copolymerization was carried out at 75 ° C. After aging at 1 ° C. for 1 hour, a vinyl acetate-butyl acrylate copolymer emulsion having a solid content of 45% was obtained.

To 100 parts of the vinyl acetate-butyl acrylate copolymer emulsion obtained above was added an ethylene-vinyl acetate copolymer emulsion (trade name “O
M-4000 ", ethylene content 15%, solid content 55
%, Manufactured by Kuraray Co., Ltd.) 50 parts, as a thickener "Viscal
7.7 parts of a dispersion obtained by sufficiently dispersing 0.2 parts of "ex AT-77" in 7.5 parts of toluene was added, and the mixture was uniformly stirred and mixed. Next, while stirring 157.7 parts of the emulsion containing the thickener and toluene obtained above with a homodisper, “calcium carbonate first grade” 3 was used as an inorganic filler.
0 parts were gradually added. Stirring was continued for 30 minutes after all of the "calcium carbonate primary" had been added, and "calcium carbonate primary" was uniformly mixed in the emulsion. Next, EDTA is used as a compound capable of forming a chelate ring.
6 parts of a dispersion obtained by sufficiently dispersing 1.98 parts in 4.02 parts of aqueous ammonia (2.5%) was added, and the mixture was uniformly stirred and mixed to obtain an adhesive composition having a solid content of 54%. .

(Example 3) To 100 parts of an ethylene-vinyl acetate copolymer emulsion "OM-4000", 0.2 part of "Viscalex AT-77" as a thickener was sufficiently dispersed in 5 parts of toluene. 5.2 parts of the dispersion liquid was added and uniformly stirred and mixed. Next, while stirring 105.2 parts of the emulsion containing the thickener and toluene obtained above with a homodisper, 20 parts of “calcium carbonate first grade” as an inorganic filler was gradually added. Stirring is continued for 30 minutes after the addition of the entire amount of “Calcium carbonate first grade”, and “Calcium carbonate first grade” is contained in the emulsion.
Was uniformly mixed. Next, 1.32 parts of EDTA as a compound capable of forming a chelate ring was added to aqueous ammonia (2.5%).
%) 2.68 parts of a dispersion sufficiently dispersed in 4 parts were added, and the mixture was uniformly stirred and mixed to obtain an adhesive composition having a solid content of 59%.

Example 4 0.1 part of aqueous ammonia (25%) was added to 100 parts of an ethylene-vinyl acetate copolymer emulsion "OM-4000" to adjust the pH (20 ° C.) to 7 parts.
After adjusting to an anionic urethane resin emulsion (trade name “UPLENE UX-306”, solid content 45%,
30 parts (manufactured by Sanyo Chemical Industry Co., Ltd.) were added, and the mixture was uniformly stirred and mixed. Next, "Viscalex AT-7" is used as a thickener.
7 "5.1 parts of a dispersion obtained by sufficiently dispersing 0.1 part of toluene in 5 parts of toluene was added and uniformly stirred and mixed. Next, 135.1 parts of a mixed emulsion of an ethylene-vinyl acetate copolymer emulsion and an anionic urethane resin emulsion containing the thickener and toluene obtained above was stirred with a homodisper, and the inorganic filler was stirred. 20 parts of “calcium carbonate first grade” was gradually added. Stirring is continued for 30 minutes after the addition of the entire amount of “Calcium carbonate first grade”, and “Calcium carbonate first grade” is contained in the emulsion.
Was uniformly mixed. Thereafter, as a compound capable of forming a chelate ring, 1.65 parts of EDTA was added to aqueous ammonia (2.5%).
%) 3.35 parts of a sufficiently dispersed dispersion 5 parts were added and uniformly stirred and mixed to obtain an adhesive composition having a solid content of 56%.

(Example 5) The adhesive composition obtained in Example 4 was used as a main ingredient, and 100 parts of this adhesive was used as a curing agent as a water-dispersible isocyanate-based curing agent (trade name "UX-
W ", 100 parts of solid content, 4 parts by Sekisui Chemical Co., Ltd.) and uniformly stirred and mixed to obtain a two-part mixed type adhesive composition having a solid content of 58%.

Comparative Example 1 An adhesive composition having a solid content of 58% was obtained in the same manner as in Example 1 except that the compound EDTA capable of forming a chelate ring was not contained.

Comparative Example 2 An adhesive having a solid content of 51% was prepared in the same manner as in Example 4 except that the inorganic filler “calcium carbonate first grade” and the compound EDTA capable of forming a chelate ring were not contained. A composition was obtained.

Comparative Example 3 An adhesive composition having a solid content of 57% was obtained in the same manner as in Example 4 except that the compound EDTA capable of forming a chelate ring was not contained.

The performance of the seven types of adhesive compositions obtained in Examples 2 to 5 and Comparative Examples 1 to 3 was evaluated in the same manner as in Example 1. The results were as shown in Table 1. However, the storage stability of the two-part mixed adhesive composition obtained in Example 5 was not evaluated.

[0114]

[Table 1]

As is clear from Table 1, the adhesive compositions of Examples 1 to 4 according to the first invention or the second invention exhibit excellent normal-state adhesive strength and heat creep resistance, and
The change in viscosity after standing at 50 ° C. for one week was small, and the storage stability was excellent. In addition, the two-part mixed adhesive composition of Example 5 according to the third invention exhibited extremely excellent heat creep resistance and excellent normal adhesive strength.

On the other hand, the adhesive composition of Comparative Example 1 or Comparative Example 3, which did not contain a compound capable of forming a chelate ring, exhibited an extremely large decrease in viscosity after standing at 50 ° C. for one week, and showed a storage stability. Sex was bad. Also, add 50% calcium carbonate
The adhesive composition of Comparative Example 2, which did not contain an inorganic filler containing at least% by weight, had extremely poor heat creep resistance and poor normal-state adhesive strength.

[0117]

As described above, the adhesive composition according to the present invention provides excellent adhesion to various adherends including porous materials without any pretreatment such as sealing or primer application. Since it exhibits adhesive strength such as force and excellent heat resistance and water resistance, and also has excellent storage stability and workability,
It is suitably used for various applications including decorative plywood, building materials, woodworking, and the like.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C09J 175: 04)

Claims (4)

[Claims] 1. An adhesive composition comprising the following components (a1), (b) and (c). (A1) Component: (co) polymer emulsion obtained by emulsifying (co) polymerizing a vinyl ester monomer alone or a vinyl ester monomer and a monomer copolymerizable with the vinyl ester monomer (b) Component: 50 parts of calcium carbonate Inorganic filler containing not less than 10% by weight (c) Component: a compound capable of forming a chelate ring 2. An adhesive composition comprising the following components (a2), (b), (c) and (d). (A2) component: ethylene-vinyl acetate copolymer emulsion (b) component: an inorganic filler containing 50% by weight or more of calcium carbonate (c) component: a compound capable of forming a chelate ring (d) component: anionic Urethane resin emulsion 3. The composition according to claim 1, further comprising a compound having two or more functional groups capable of reacting with an active hydrogen atom in the molecule as the component (e).
The adhesive composition according to item 1. 4. The adhesive composition according to claim 1, wherein the component (c) is ethylenediaminetetraacetic acid.