JPH027347B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-based contact adhesive composition that has a property of being sticky when dried at room temperature and becoming non-tacky with the passage of time, has a high initial adhesive strength, and has excellent water resistance and heat resistance. It is. Currently, the mainstream industrial adhesives are thermosetting resin-based or emulsion-based adhesives, and solvent-free adhesives have also been used for a long time. On the other hand, most adhesives made from chloroprene rubber are solvent-based, and there is a growing movement to convert them into emulsions from the standpoint of health and safety. Solvent-based adhesives using chloroprene rubber have (1) good contact properties; (2) High crystallinity and strong initial adhesion. (3) Good heat resistance and water resistance. It has the following characteristics and is used in a wide range of applications such as woodworking, plywood, and vehicle adhesives. However, emulsion adhesives using chloroprene rubber have lower initial adhesion than conventional solvent-based adhesives, and are also inferior in heat resistance and water resistance. Therefore, various proposals have been made to improve these drawbacks, but nothing satisfactory has yet been achieved. In view of these facts, the present inventors have conducted intensive studies to find a water-based contact adhesive composition that has high initial adhesive strength and excellent heat resistance and water resistance, and as a result, they have completed the present invention. It has arrived. That is, the present invention emulsifies and disperses (A) an ethylenic monomer and a compound having one or more epoxy groups and 0.1 to 1 (meth)acryloyl group per molecule in an aqueous medium. A polyamine curing agent or a polysulfide curing agent is added in an amount of 0.2 to 2.0 equivalents per equivalent of the epoxy group of the compound having an epoxy group described in (B) and (A) to a polymer obtained by emulsion polymerization. The water-based contact adhesive composition and the second invention contain (A) an ethylenic monomer and 1 ethylenic monomer per molecule.
(B), (A This is a water-based contact adhesive composition prepared by adding 0.2 to 2.0 equivalents of a polyamine curing agent or a polysulfide curing agent to 1 equivalent of the epoxy group of the compound having an epoxy group described in ). The aqueous contact adhesive composition of the present invention imparts so-called contact properties due to the film-forming action of the ethylenic monomer component in the polymer and the tackiness of the epoxy compound and polyamine or polysulfide curing agent. In addition, due to the crosslinking reaction between the epoxy compound and the curing agent over time, it is possible to impart higher adhesion and heat resistance and water resistance that are higher than conventional solvent-based adhesives. Furthermore, since the composition of the present invention causes a crosslinking reaction when a curing agent is mixed with the epoxy compound, it is inevitably a two-component adhesive when room temperature curing is required. It is also possible to use a one-component type curing agent using a high temperature curing type or a latent curing type curing agent. The present invention will be explained in detail below. The ethylenic monomer used in the present invention includes acrylic acid alkyl esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and methacrylic acid corresponding to the above alkyl esters. alkyl esters of , aromatic vinyl compounds such as styrene, α-methylstyrene, and vinyltoluene, α,β-ethylenically unsaturated dicarboxylic acids such as monobutyl maleate, dibutyl maleate, monooctyl fumarate, and dioctyl fumarate. mono- or diesters, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers, unsaturated nitriles such as acrylonitrile and methacrylonitrile, olefins such as ethylene, butadiene and isoprene, vinyl chloride, vinylidene chloride, etc. Examples include chlorine-containing vinyl compounds. In addition, if desired, the above-mentioned ethylenic monomers may be used as main components, and ethylenic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, fumaric acid, maleic acid, itaconic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, etc. , hydroxyl group-containing monomers such as polyethylene glycol monomethacrylate, amide group-containing monomers such as acrylamide and methacrylamide, methylol group-containing monomers such as N-methylolacrylamide and dimethylolacrylamide, N-butoxymethyl Alkoxymethyl group-containing monomers such as acrylamide, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, divinyl monomers such as divinylbenzene, polyoxyethylene diacrylate, and polyoxyethylene dimethacrylate. It is possible to combine functional or crosslinking monomers such as. The compound used in the present invention having one or more epoxy groups and 0.1 to 1 (meth)acrylate group per molecule (hereinafter referred to as an epoxy acrylate compound) has acrylic acid per equivalent of epoxy group in the epoxy compound. acid or methacrylic acid from 0.1 to
It is obtained by reacting in the range of 1.0 mol. Here, the epoxy compound is a compound having one or more epoxy groups per molecule, and specific examples include resins with an epoxy equivalent of 100 to 4,000, preferably 130 to 1,000, such as epichlorohydrin or methylepichlorohydrin and phenol. Examples include condensates with other compounds. Examples of phenolic compounds in this case include 2,2'-bis(4,4'-hydroxyphenyl)propane (commonly known as bisphenol A),
Halogenated bisphenol A, 2,2'-bis(4,4'-hydroxyphenyl)methane (commonly known as bisphenol F), resorcinol, tetrahydroxyphenylethane, phenol, a novolak type polyester condensed from cresol and formalin. Examples include functional phenols. Other diglycidyl ethers of polyalkylene glycols such as polypropylene glycol, aromatic or alicyclic glycidyl esters and dimer acid diglycidyl esters such as hexahydrophthalic acid diglycidyl ether, phthalic acid diglycidyl ester, and internal cyclic imino groups. Examples include glycidylamines obtained from hydantoin, which is a mononuclear nitrogen heterocyclic compound. If each molecule has one or less epoxy groups, the desired water resistance and heat resistance will be poor and it will not be possible to provide satisfactory results. By using the epoxy acrylate compound obtained in this way, it is possible to improve the compatibility with the ethylenic monomer, thereby improving the storage stability of the aqueous dispersion and coating film. homogeneous transparency can be increased. If the number of (meth)acryloyl groups per molecule is less than 0.1, the stability of the resulting aqueous dispersion is poor and layer separation occurs, and if the number is less than 1, gelation occurs during emulsion polymerization, which is not practical. Examples of the synthetic rubber used in the second aspect of the present invention include copolymers of butadiene and styrene or acrylonitrile, polymers of chloroprene, copolymers of isobutylene and isoprene, copolymers of butadiene and vinylpyridine, etc. Can be done. Preferably it is a copolymer of butadiene and acrylonitrile, more preferably butadiene and acrylonitrile containing --COOH, -- in one molecule.
It is a copolymer of ethylenic monomers having at least one functional group selected from OH, -NH, or _-NH2 . The amount of synthetic rubber used is the sum of ethylenic monomer and epoxy acrylate compound.
It is preferably 1 to 50 parts by weight per 100 parts by weight. When the above-mentioned synthetic rubber components are added, it goes without saying that the adhesive peel strength can be improved, but surprisingly, the pot life when a curing agent is added at the time of use is significantly extended. . Examples of the polyamine curing agent used in the present invention include ethylenediamine, diethylenetriamine,
Aliphatic polyamines such as triethylenetetramine and tetraethylenepentamine, alicyclic polyamines such as isophoronediamine, menthanediamine, and N-aminoethylpiperazine, xylylenediamine, phenylenediamine, diaminodiphenylmethane, and diaminodiphenyl sulfone. aromatic amines and heterocycle-containing polyamines, modified polyamines modified from these amines, polyamide polyamines synthesized from natural or synthetic dicarboxylic acids and polyamines such as ethylenediamine,
Examples include tertiary amine-containing compounds such as dimethylbenzylamine and 2,4,6-tridimethylaminomethylphenol, imidazoles, and dicyandiamide. Examples of the polysulfide curing agent used in the present invention include HS-(C ₂ H ₅ -O-CH ₂ -O-
C ₂ H ₄ ―S―S―) _o C ₂ H ₄ ―O―CH ₂ ―O―C ₂ H ₄ ―
Compounds having a structure like SH can be mentioned. This curing agent is characterized by rapid strength development, especially when used in winter. The emulsion polymer used in the present invention contains an ethylenic monomer and an epoxy acrylate compound.
Stir thoroughly in advance at room temperature or at a temperature of 100°C in a ratio of 10:90 (parts by weight) to 90:10 (parts by weight), preferably 40:60 (parts by weight) to 60:40 (parts by weight). It can be obtained by a method of uniformly dissolving the emulsion by adding a surfactant, a dispersant, a protective colloid, etc., water, and a polymerization initiator to make an emulsion dispersion, which is then subjected to emulsion polymerization. In the second invention, 1 to 50 parts by weight of synthetic rubber is added to and mixed with 100 parts by weight of the above mixed solution of ethylenic monomer and epoxy acrylate compound, and a surfactant, It can be obtained by adding a dispersant, a protective colloid, etc., water, and a polymerization initiator to form an emulsion dispersion, followed by emulsion polymerization. This emulsion polymerization method is a conventionally known method. surfactant used,
Examples of dispersants and protective colloids include aliphatic soaps, alkyl sulfate salts, alkylbenzene sulfonate salts, dialkyl sulfosuccinate salts, alkyl phosphate salts, polyoxyethylene alkyl ethers, and polyoxyethylene alkyl phenol ethers. , polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, glycerin fatty acid ester, oxyethylene oxypropylene block copolymer, alkylamine salt, polyphosphate, polyacrylate, maleic anhydride copolymer salt, polyvinyl alcohol , hydroxyethylcellulose, etc. Further, as the polymerization initiator for the ethylenic monomer, for example, a persulfate, a peroxide, an azobis compound, and a redox system in which these are combined with a reducing agent are used. Further, a PH adjuster such as sodium hydrogen phosphate or sodium hydrogen carbonate and an organic solvent are added as necessary. By following the above emulsion polymerization method, not only the manufacturing process is simplified, but also products with less variation in quality can be manufactured. In the aqueous contact adhesive composition of the present invention, the active hydrogen group of the polyamine or polysulfide curing agent is 0.2 to 2.0 equivalent, preferably 0.5 to 2.0, per equivalent of the epoxy group of the epoxy acrylate compound in the emulsion polymer. Produced by adding 1.0 equivalents. If the amount added is less than 0.2 equivalents or more than 2.0 equivalents, adhesiveness will be reduced. The solids content of the composition produced in this way can be up to about 70% by weight, but from the standpoint of quality and efficiency, the solids content is 30-60%.
Weight percent is preferred. Adhesives such as phenolic resins, terpene resins, rosin gums, rosin ester resins, and xylene resins can be added to the compositions of the present invention in order to further improve the contact properties of the compositions. The adhesive is preferably added in a water-dispersed or water-soluble form, and the amount added is equal to the total amount of the ethylenic monomer and epoxy acrylate compound.
It is preferably 5 to 100 parts by weight per 100 parts by weight. In addition, to improve adhesion to glass etc.
Silane compounds such as vinyltriethoxysilane, β-(2,4epoxycyclohexyl)ethyltrimethoxysilane, etc. can be added. The method of using the composition of the present invention is to add and mix a polyamine-based or polysulfide-based curing agent to an emulsion polymer, apply it to the desired thickness on an adherend, leave it for a certain period of time, and then apply it to the other adherend. Either the body is superimposed on the part and bonded, or an emulsion polymer is applied to one side of the adherend and a curing agent component is applied to the other adherend, and the emulsion polymer of both adherends is bonded. It can be used in a method of laminating and bonding the coated surface and the hardener coated surface so that they are in contact with each other. In particular, the latter method has the advantage of extending pot life. In addition, various methods such as spraying, roll coating, brushing, etc. can be used for coating the surface to be adhered. Furthermore, the composition of the present invention can be applied to wood, plywood, partail board, gypsum board, metals such as iron and aluminum, plastic films and molded products thereof, leather, fabrics such as cotton and hemp, glass fibers, glass cloths, and FRP. Used for adhering objects to each other or different types, such as Hereinafter, it will be explained in detail using examples. In the examples, unless otherwise specified, parts or % represent the heaviest part or weight %. Example 1 7.2 parts of acrylic acid and 0.1 part of sodium methylate were added as a catalyst to 190 parts of epoxy resin A, E, R-331 (bisphenol A type epoxy resin, epoxy equivalent: 190, manufactured by Asahi Kasei Corporation) in advance. , the reaction is carried out at 130°C for about 5 hours until the acid value becomes 1 or less.
In this way, epoxy acrylate A having an average of 0.2 acroyl groups and 1.8 epoxy groups per molecule was obtained. Using this epoxy acrylate A, a polymerizable mixture was prepared as follows. Styrene 20 parts n-butyl acrylate 20 parts Methyl methacrylate 10 parts Polyoxyethylene lauryl ether (HLB
= 17.5) 2 parts Na dicyclohexyl sulfosuccinate 2 parts Ammonium persulfate 2 parts Epoxy acrylate A 50 parts Demineralized water 30 parts Total 136 parts Note (1) AER-331 is a bisphenol A type epoxy resin with an epoxy equivalent of 190 (manufactured by Asahi Kasei Corporation) ) and has an average of two epoxy groups per molecule. Pour 64 parts of desalinated water prepared separately into a flask, and
Increase temperature to ℃. The above polymerizable mixture was added dropwise into the solution over a period of about 2 hours. Approximately 2 hours after dripping70
The temperature was maintained at 80°C, and then 2 parts of ammonium persulfate was added, the temperature was raised to 80°C, and the reaction was continued for 2 hours to obtain an emulsion polymer. The obtained emulsion polymer (hereinafter referred to as emulsion polymer A) had an average particle size of 0.2 μ, was a milky white emulsion, and was stable at 40° C. for 10 days. 6 parts of triethylenetetramine (hereinafter referred to as TETA) as a hardening agent was added to 200 parts of this emulsion polymer A and mixed uniformly to prepare a contact adhesive.
The pot life of this adhesive was 4 hours. Using this adhesive, in order to bond the plywood together, apply it to each plywood so that the dry film thickness is 30μ,
After application, the adhesive was allowed to stand for 10 minutes, and then a pressure of 3 kg/cm ² was applied for approximately 5 seconds to effect adhesion. The tensile shear adhesive strength was measured immediately after adhesion and was found to be 5 kg/cm ² . (Green strength) After adhesion, the adhesive strength increased with time, and the tensile shear adhesive strength after about one day was 50 Kg/cm ² . Examples 2 to 5 Emulsion polymers B, C, D and E shown in Table 1 were prepared in the same manner as in Example 1.

[Table] TETA was added to the emulsion polymers B, C, D, and E as shown in Table 2 to prepare a water-based contact adhesive composition. This composition was used to bond plywood and tinplate in the same manner as in Example 1.
Its adhesive performance is shown in Table 2.

[Table] Example 6 200 parts of the emulsion polymer A obtained in Example 1, a commercially available aqueous phenol resin dispersion (nonvolatile content 50%, manufactured by Showa Union Co., Ltd.) and 2-ethyl-4 as a curing agent were added.
- A contact adhesive was obtained using 3 parts of methylimidazole. The pot life of this adhesive was over 12 hours. Using this adhesive, asbestos slate and cotton canvas,
The film was applied to each adherend to a dry film thickness of 30μ, and after being left for 5 minutes, a pressure of 1Kg/cm ² was applied for about 2 seconds to bond it, resulting in a green strength of 15Kg/cm2. It was ² . Example 7 An adhesive composition was produced by adding 20 parts of Thiokol LP-3 (manufactured by Thiokol Co., Ltd., trade name) to 200 parts of the emulsion polymer A obtained in Example 1, and this composition was used to bond plywood and PVC boards were adhered in the same manner as in Example 1, and the green strength was measured. The result is 14Kg/
It was warm in ^cm2 . Example 8 16.5 parts of methacrylic acid and 0.1 part of sodium methylate were added as a catalyst to 190 parts of epoxy resin AER-331 in advance, and the mixture was heated at 120°C until the acid value became 1 or less.
The reaction is carried out for about 5 hours. In this way, a compound epoxy acrylate B having an average of 0.4 acryloyl groups and 1.6 epoxy groups per molecule was obtained. Using this, a polymerizable solution is prepared as follows. Styrene 10 parts n-butyl acrylate 20 parts Methyl methacrylate 10 parts Polyoxyethylene lauryl ether (HLB
= 18.1) 2 parts Na dicyclohexyl sulfosuccinate 2 parts Ammonium persulfate 2 parts Epoxy acrylate B 50 parts Hiker CTBN1300 x 13 ¹⁾ 10 parts Demineralized water 30 parts 136 parts Note 1) Hiker CTBN1300 x 13 is manufactured by Ajibe Kosansha. Indicates NBR (molecular weight approximately 3500). Emulsion polymerization was carried out in the same manner as in Example 1 to obtain emulsion polymer F. The average particle size of the emulsion polymer F was 0.1μ, and it was stable at 40°C for 30 days. Add 2 parts of TETA to 200 parts of this emulsion polymer F,
The mixture was mixed uniformly to form a contact adhesive. The pot life of this adhesive was 12 hours. Example 9 To 200 parts of the emulsion polymer F obtained in Example 8, 0.5 part of dicyandiamide and 0.1 part of 2-methylimidazole were added.
% and mixed uniformly to form a contact adhesive. The pot life of this adhesive at room temperature was more than one month, and after being left for one month, a film-like molded article having a tensile strength of 8 kg/mm ² was obtained by heat treatment at 100° C. for 1 hour.

Claims (1)

[Claims] 1 (A) An ethylenic monomer and a compound having one or more epoxy groups and 0.1 to 1 (meth)acryloyl group per molecule are emulsified and dispersed in an aqueous medium. (B) 0.2 to 2.0 equivalents of a polyamine curing agent or a polysulfide curing agent are added to the polymer obtained by emulsion polymerization based on 1 equivalent of the epoxy group of the compound having an epoxy group described in (A). Water-based contact adhesive composition. 2 (A) An ethylenic monomer, a compound having one or more epoxy groups and 0.1 to 1 (meth)acryloyl group per molecule, and a synthetic rubber are emulsified and dispersed in an aqueous medium, and then emulsified. (B) A water-based polymer obtained by adding 0.2 to 2.0 equivalents of a polyamine curing agent or a polysulfide curing agent to 1 equivalent of the epoxy group of the compound having an epoxy group described in (A). Contact adhesive composition.