JP2007091999A - Aqueous primer composition, method of surface treatment using the same and laminated structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous primer composition which facilitates lowering of odor and speeding up in the surface treatment of inorganic substrates for civil engineering buildings such as a roof, a wall, a floor and a road, is excellent in drying the primer accumulated in a recessed part, suppresses foaming of a coated resin layer of a urethane resin and is further excellent in adhesion to inorganic substrates and effectively preventing a coated resin layer from swelling; to provide a method of surface treatment using the same; and to provide the resultant laminated structure. <P>SOLUTION: The aqueous primer composition comprises (A) a water-dispersible polyisocyanate, (B) water and (C) cement as essential components, and optionally (D) an acrylic resin aqueous dispersion. The method of surface treatment for the inorganic substrates by coating the composition onto the inorganic substrates, and the resultant laminated structure are also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a water-based primer composition for civil engineering construction, a method for ground treatment of an inorganic base material of a civil engineering building using the same, and a laminated structure. More specifically, it can be used for the surface treatment of inorganic base materials such as concrete, asphalt such as roofs, walls, floors, roads, etc., and the odor and speed of the surface treatment process can be reduced, and adhesion to various inorganic base materials can be achieved. The present invention relates to an aqueous primer composition that is excellent in the effect of preventing the swelling of the coating resin layer, has little odor, and is excellent in drying properties, and further relates to a base treatment method and a laminated structure using the aqueous primer composition.

In general, civil engineering buildings made of inorganic base materials such as mortar and concrete are often provided with a coating resin layer such as waterproofing materials, flooring materials, and sealing materials for the purpose of preventing corrosion and deterioration of the inorganic base material. A primer is used as a base treatment to improve the adhesion of the layer.
Examples of civil engineering and construction primers include urethane resin and epoxy resin, all of which contain a large amount of organic solvent for the purpose of improving application workability and penetration into the ground. Since there is concern about not only adverse health effects but also indoor air pollution (sick house) and air pollution, it has been expected to reduce the use of organic solvents by making the primer water-based.

  Primers in the waterproof method and coating floor method are excellent in drying properties immediately after application, as well as in basic performance such as permeability to various inorganic substrates, shielding properties, adhesiveness, and durability performance such as water-resistant adhesion. There must be. However, there are some solvent-based primers that satisfy the performance, but no water-based primer has yet been found that satisfies all the requirements.

  In general, water-based resins can be broadly classified into water-soluble resins and water-dispersible resins with particle morphology. Water-dispersible resins, especially emulsions with large particle diameters, are suitable for drying at room temperature, and penetrate into inorganic substrates. In terms of properties, water-soluble resins are suitable. In other words, when using a water-based resin as a primer, it is difficult to satisfy all the required performance with a water-soluble resin or a water-dispersible resin alone, and in order to impart durability performance such as water-resistant adhesion, Toughening by cross-linking is required.

  In order to meet these demands, a method has been proposed in which a crosslinkable aqueous resin is used for the base treatment of an inorganic substrate. For example, a method of diluting an emulsifying hydrophilic group-containing isocyanate prepolymer with water and using it for the base treatment is disclosed (see, for example, Patent Documents 1 and 2). However, these methods are excellent in terms of not using an organic solvent, impregnating the porous inorganic base material, and reinforcing the surface layer of the base material. Since there is a problem that it cannot move quickly to the next process because of its slow speed, and the shielding property is poor, the coating resin layer such as waterproofing and flooring applied on it is easily affected by the moisture of the underlying concrete and swells. There is a problem that is likely to occur.

Furthermore, a method is disclosed in which an aqueous primer composition comprising an emulsifying hydrophilic group-containing isocyanate prepolymer and an emulsion resin liquid is used for the base treatment (see, for example, Patent Document 3).
However, although this method is excellent in terms of not using an organic solvent and impregnating the porous inorganic base material and strengthening the surface layer of the base material, since the molecular weight of the emulsion resin is small, when used in waterproofing and coating floor methods, It has poor shielding properties, and the coating resin layer such as a waterproofing material or a flooring material applied thereon is easily affected by the moisture of the underlying concrete and is likely to swell. Further, in the case of a porous inorganic base material that is not preheated by a hot air dryer or the like, there is a problem that the drying property is slow and it is not possible to quickly move to the next process.

Further, an aqueous resin composition comprising a combination of three kinds of a hydroxyl group-containing aqueous acrylic resin having a crosslinked structure, a hydroxyl group-containing aqueous urethane resin having a crosslinked structure, and a polyisocyanate compound dispersible in water is disclosed (for example, Patent Document 4). reference). The coating material comprising this composition has excellent adhesion to a resin substrate such as a urethane sheet, water resistance and water adhesion, but has a low proportion of hydroxyl group-containing water-based acrylic resin and therefore has low permeability to an inorganic substrate. Also, the adhesiveness tends to decrease.
JP-A-6-92756 JP 2004-010777 A JP 2004-196914 A JP 2000-265053 A

  It is an object of the present invention to achieve a low bromide and speed-up of a base treatment process for an inorganic base material of civil engineering buildings such as roofs, walls, floors, roads, etc. An aqueous primer composition that suppresses foaming of the coating resin layer and is excellent in adhesion to an inorganic base material and has an excellent anti-dandruff effect on the coating resin layer, a base treatment method using the same, and a laminated structure thereof It is in.

Therefore, as a result of intensive studies on the above problems, the present inventors have found that an aqueous primer composition containing water-dispersible polyisocyanate (A), water (B), and cement (C) as essential components has little odor and is dried. Excellent in permeability, good permeability to various inorganic base materials and toughening by cross-linking is possible. Excellent adhesion to the base material and excellent shielding properties. The inventors found that no blistering occurred and completed the present invention.
That is, the present invention provides an aqueous primer composition comprising water-dispersible polyisocyanate (A), water (B) and cement (C) as essential components.

  In addition, the present invention provides a method for ground treatment of an inorganic base material, which comprises applying the aqueous primer composition to the inorganic base material.

Furthermore, the present invention is composed of at least three layers: an inorganic base material layer, a resin layer composed of the above aqueous primer composition, and a coating resin layer composed of any one of an epoxy resin, a urethane resin, and a polymerizable unsaturated resin. A laminated structure is provided.
In this specification, “acrylic acid” and “methacrylic acid” are collectively referred to as (meth) acrylic acid, and “acrylate” and “methacrylate” are collectively referred to as (meth) acrylate.

  The water-based primer composition of the present invention can reduce the bromide and speed of the base treatment process, and is excellent in adhesion to an inorganic base material, anti-dandruffing effect and drying property of the coating resin layer, so that the roof, wall, floor, It is useful for ground treatment of various inorganic base materials for civil engineering and construction such as roads, and can provide a highly reliable laminated structure.

Hereinafter, the present invention will be described in more detail.
First, the water-dispersible polyisocyanate (A) used in the present invention will be described.

The water-dispersible polyisocyanate (A) used in the present invention means a polyisocyanate that can form a water dispersion when stirred in water, and includes various known and commonly used water-dispersible polyisocyanates. It is done. The isocyanate group content is preferably 10 to 30% by weight, more preferably 10 to 20% by weight.
Examples of known and commonly used water-dispersible polyisocyanates include (1) a mixture of a hydrophobic polyisocyanate and a polyisocyanate having a hydrophilic group, and (2) a hydrophobic polyisocyanate having no isocyanate group but having a hydrophilic group. Examples thereof include a mixture with a dispersant having (3) a polyisocyanate having a hydrophilic group alone. Of these, the water-dispersible polyisocyanate (1) is preferred from the viewpoint of swelling resistance and the like.

  The hydrophobic polyisocyanate is one having no hydrophilic group such as various known anionic groups, cationic groups and nonionic groups in the molecule, such as 1,4-tetramethylene diisocyanate, Ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate (hereinafter referred to as HDI), 1,12-dodecamethylene diisocyanate, 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate, etc. Aliphatic diisocyanates; aliphatic triisocyanates such as 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanate methyloctane, 2-isocyanatoethyl (2,6-diisocyanate) hexanoate;

  1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanatecyclohexane, 3,5,5-trimethyl (3-isocyanatemethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4 '-Diisocyanates, alicyclic diisocyanates such as 2,5- or 2,6-diisocyanate methyl norbornane; alicyclic triisocyanates such as 2,5- or 2,6-diisocyanate methyl-2-isocyanate propyl norbornane; aralkylene diisocyanates such as m-xylylene diisocyanate, α, α, α′α′-tetramethyl-m-xylylene diisocyanate;

  m- or p-phenylene diisocyanate, tolylene-2,4- or 2,6-diisocyanate, diphenylmethane-4,4′-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4′-diisocyanate, 4,4 Aromatic diisocyanates such as' -diisocyanate-3,3'-dimethyldiphenyl, 3-methyl-diphenylmethane-4,4'-diisocyanate, diphenylether-4,4'-diisocyanate; triphenylmethane triisocyanate, tris (isocyanatephenyl) Aromatic triisocyanates such as thiophosphate;

  Polyisocyanates having a uretdione structure obtained by cyclizing and dimerizing the isocyanate groups of the various diisocyanates or triisocyanates described above; Isocyanates obtained by cyclizing and trimerizing the isocyanate groups of the various diisocyanates or triisocyanates described above A polyisocyanate having a nurate structure; a polyisocyanate having a burette structure obtained by reacting the aforementioned various diisocyanates or triisocyanates with water; an oxadiater obtained by reacting the various diisocyanates or triisocyanates with carbon dioxide Examples include polyisocyanates having a gintrione structure; polyisocyanates having an allophanate structure.

  Examples of the hydrophilic group of the polyisocyanate having a hydrophilic group include various known and commonly used anionic groups, cationic groups, and nonionic groups. In the aqueous primer composition of the present invention, the hydrophilic group is preferably a nonionic group from the viewpoint of shielding properties, and among these, a polyoxyethylene group is more preferable.

Examples of the above-mentioned polyisocyanate having a hydrophilic group include a polymer having the hydrophilic group and an isocyanate group. Examples of the polymer include polyether, polyester, polyurethane, vinyl polymer, alkyd resin, fluororesin, and silicon. Examples thereof include resins. Among these, from the viewpoint of water dispersibility, it is preferable to use a polyether or a vinyl polymer having a hydrophilic group and an isocyanate group. These can be used alone or in combination of two or more.

  Of the polyisocyanates having a hydrophilic group that can be used in the present invention, a polyether having an isocyanate group and a hydrophilic group will be described.

  The polyether having an isocyanate group and a hydrophilic group can be produced, for example, by reacting a polyether compound having both a hydrophilic group and an active hydrogen-containing group with the hydrophobic polyisocyanate.

  Examples of the polyether compound having both a hydrophilic group and an active hydrogen-containing group include monoalkoxy polyoxyethylene glycol, monoalkoxy polyoxyethylene-polyoxypropylene glycol, polyoxyethylene glycol, polyoxyethylene-polyoxypropylene. Examples thereof include hydroxyl group-containing polyethers such as glycol, and these can be used alone or in combination of two or more.

  When producing a polyether having an isocyanate group and a hydrophilic group, an excessive amount of a hydrophobic polyisocyanate is used with respect to the polyether compound having both the hydrophilic group and the active hydrogen-containing group. By this, the polyether which has the said isocyanate group and a hydrophilic group, ie, the mixture of the polyisocyanate which has a hydrophilic group, and hydrophobic polyisocyanate can be manufactured by one-step reaction.

  Moreover, it is preferable to introduce a hydrophobic group having 3 or more carbon atoms into the above-described polyether having an isocyanate group and a hydrophilic group, whereby the pot life of the aqueous primer composition of the present invention is improved. Can be made sufficiently long.

  Examples of the hydrophobic group having 3 or more carbon atoms include alkyl groups such as n-propyl group, iso-propyl group, n-butyl group and hexyl group, and alicyclic alkyl groups such as cyclopentyl group and cyclohexyl group. And aromatic groups such as a phenyl group.

  Examples of a method for introducing a hydrophobic group having 3 or more carbon atoms into the polyether having an isocyanate group and a hydrophilic group include, for example, a polyether compound having both the hydrophilic group and the active hydrogen-containing group. And a method of reacting a compound having a hydrophobic group having 3 or more carbon atoms with an active hydrogen-containing group and a hydrophobic polyisocyanate.

  The polyisocyanate having a hydrophilic group that can be used in the present invention is particularly preferably a vinyl polymer having an isocyanate group and a hydrophilic group.

  Examples of such vinyl polymers include acrylic polymers, fluoroolefin polymers, vinyl ester polymers, aromatic vinyl polymers, polyolefin polymers, and the like. Among these polymers, an acrylic polymer having an isocyanate group and a hydrophilic group is used from the viewpoint of compatibility with the acrylic resin aqueous dispersion (D) described later used in the aqueous primer composition of the present invention. It is preferable to do.

  Examples of the vinyl polymer having an isocyanate group and a hydrophilic group include a) a method of polymerizing a vinyl monomer having an isocyanate group and a vinyl monomer having a hydrophilic group, and b) an active hydrogen-containing group. It can be produced by reacting a vinyl polymer having an active hydrogen-containing group obtained by polymerizing a vinyl monomer having a hydrophilic group and a vinyl monomer having a hydrophilic group with polyisocyanate.

  Examples of the vinyl monomer having an isocyanate group that can be used in the production method a) include 2-isocyanate propene, 2-isocyanate ethyl vinyl ether, 2-isocyanate ethyl methacrylate, m-isopropenyl-α, α-dimethyl. Examples thereof include reaction products of benzyl isocyanate, polyisocyanate and a vinyl monomer having a hydroxyl group.

  Examples of vinyl monomers having a hydrophilic group that can be used in the production method a) include alkoxypolyoxy such as methoxypolyethylene glycol (meth) acrylate, butoxypolyethylene glycol (meth) acrylate, and methoxypolyoxyethylene vinyl. Examples thereof include vinyl monomers having an anionic group represented by vinyl monomers having an ethylene group, sodium alkylallylsulfonate, sodium alkylallylphosphate, and the like.

  Examples of the active hydrogen-containing group of the vinyl monomer that can be used in the production method b) include a hydroxyl group, a carboxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, a sulfinic acid group, a mercapto group, a silanol group, and an activity. Examples include a methylene group, a carbamate group, a ureido group, a carboxylic acid amide group, and a sulfonic acid amide group. Among these, a hydroxyl group, an amino group, a carboxyl group, and an active methylene group are preferable from the viewpoint of easy introduction of the active hydrogen-containing group into the vinyl polymer, and among these, a hydroxyl group and a carboxyl group are more preferable. The active hydrogen-containing group may be introduced alone or two or more functional groups may be simultaneously introduced into the vinyl polymer.

  Examples of the vinyl monomer having an active hydrogen-containing group that can be used in the production method b) include acrylate monomers such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxypropyl methacrylate. Moreover, as a vinyl-type monomer which has a hydrophilic group, the thing similar to what can be used by the said manufacturing method a) can be used.

  In the production methods a) and b), a vinyl monomer having a hydrophobic group having 4 or more total carbon atoms can be used in combination. By using such a vinyl monomer, the reaction between the water-dispersible polyisocyanate and water can be prevented, and the aqueous primer composition of the present invention can have a sufficient pot life.

  As a method for introducing a hydrophobic group having 4 or more total carbon atoms into a vinyl polymer having an isocyanate group and a hydrophilic group, for example, vinyl having a hydrophobic group having 4 or more total carbon atoms can be used. Examples thereof include a method in which a monomer is copolymerized with another vinyl monomer in the production method a) or b) described above.

  Examples of the vinyl monomer having a hydrophobic group having 4 or more total carbon atoms include n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, An alkyl group having 4 or more carbon atoms such as 2-ethylhexyl group, n-octyl group, n-dodecyl group or n-octadecyl group; cyclopentyl group, cyclohexyl group, cyclooctyl group, dicyclopentanyl group, bornyl group, It has a cycloalkyl group having 4 or more carbon atoms such as an isobornyl group, and specific examples thereof include acrylate monomers such as n-butyl acrylate and n-butyl methacrylate.

  In addition to the various vinyl monomers described above, other vinyl monomers are used in combination with the vinyl polymer having a hydrophilic group and an isocyanate group as long as the object of the present invention is achieved. be able to.

  Examples of the other vinyl monomers include acrylic monomers such as methyl acrylate and methyl methacrylate.

  The weight-average molecular weight of the vinyl polymer having an isocyanate group and a hydrophilic group thus obtained is preferably from 2,000 to 100,000 from the viewpoint of dispersibility in water and stability of the isocyanate group in water. A range of 000 to 50,000 is more preferable.

  When a mixture of the vinyl polymer having the hydrophilic group and isocyanate group and the hydrophobic polyisocyanate described above is used as the water-dispersible polyisocyanate (A) of the present invention, the weight ratio between the two (hydrophilic group and isocyanate group). The vinyl polymer (A2) / hydrophobic polyisocyanate (A1)) having a ratio of 0.5 / 9.5 to 7/3 is preferable, and 1/9 to 5/5 is more preferable. A range of 2/8 to 4/6 is more preferable.

  The mixture of the vinyl polymer (A2) having the hydrophilic group and the isocyanate group and the hydrophobic polyisocyanate (A1) can be obtained by using an excessive amount of the hydrophobic polyisocyanate in the production method a) or b). , Can be produced by a one-step reaction.

  Examples of the dispersant having no isocyanate group but having a hydrophilic group include, for example, vinyl monomers having an isocyanate group and monomers having an active hydrogen-containing group among the aforementioned vinyl monomers. In addition, vinyl polymers obtained using the various vinyl monomers described above can be mentioned.

  As the water-dispersible polyisocyanate (A), the hydrophobic polyisocyanate may be used in combination with a polyisocyanate having the hydrophilic group and a dispersant having no isocyanate group but having a hydrophilic group. In this case, the ratio of the polyisocyanate (A2) having a hydrophilic group to the hydrophobic polyisocyanate and the dispersant having a hydrophilic group but no isocyanate group [(polyisocyanate having a hydrophilic group + isocyanate group The dispersing agent having a hydrophilic group) / hydrophobic polyisocyanate] is preferably in the range of 0.5 / 9.5 to 7/3, preferably in the range of 1/9 to 5/5. Is more preferable, and the range of 2/8 to 4/6 is most preferable.

  In addition, the polyisocyanate having a hydrophilic group can be used by diluting with an organic solvent inert to the isocyanate group within the range of achieving the object of the present invention.

  Examples of the organic solvent include aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane, and cyclopentane; aromatic hydrocarbons such as toluene, xylene, and ethylbenzene. Various esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, and ethylene glycol monomethyl ether acetate; various ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone, and cyclohexanone;

  Polyalkylene glycol dialkyl ethers such as diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether and dipropylene glycol dimethyl ether; polyalkylene glycol monoalkyl ether acetates such as ethylene glycol methyl ether acetate, propylene glycol methyl ether acetate and diethylene glycol methyl ether acetate ; Ethers such as 1,2-dimethoxyethane, tetrahydrofuran and dioxane; N-methylpyrrolidone, dimethylformamide, dimethylacetamide, ethylene carbonate and the like can be mentioned, and these can be used alone or in combination of two or more. .

  Next, the water (B) used in the present invention is general water such as tap water, distilled water or ion exchange water, and may contain water-soluble or water-dispersible organic solvents. Good.

  Next, the cement (C) used in the present invention will be described.

Examples of the cement used in the present invention include CaO 45-75% by weight, SiO ₂ 15-30% by weight, and the rest containing, for example, Al ₂ O ₃ , Fe ₂ O ₃ , MgO, SO _3. A typical one is ordinary Portland cement, and other examples include early strength, very early strength, moderate heat, and sulfate resistance. In addition, mixed cement, that is, blast furnace cement, silica cement, fly ash cement, and the like are also included.

  Further, special cements such as white cement, alumina cement, oil well cement, colloidal cement, thermosetting cement, high sulfate slag cement, geothermal cement and the like can also be mentioned. These may be used alone or in combination of two or more.

  The cement used in the present invention is preferably ordinary Portland cement defined in JIS R 5210 from the viewpoint of pot life.

  From the viewpoint of pot life and coating workability, 5 to 400 parts by weight of cement (C) is added to 100 parts by weight of the solid content of the liquid obtained by mixing water-dispersed polyisocyanate (A) and acrylic resin aqueous dispersion (D). It is preferable to add, and it is more preferable to add 30 to 300 parts by weight.

  In the present invention, it is further preferable that the aqueous primer composition contains an acrylic resin aqueous dispersion (D) from the viewpoint of preventing swelling of the coating resin layer.

  The acrylic resin of the acrylic resin aqueous dispersion (D) has a polystyrene-equivalent weight average molecular weight of 350,000 or more measured by gel permeation chromatography and a glass transition temperature of 15 measured by a differential scanning calorimeter. It is -130 degreeC.

  The acrylic resin aqueous dispersion (D) used in the present invention is one in which an acrylic resin is dispersed in an aqueous medium, and examples thereof include various known and common acrylic resin aqueous dispersions. Broadly speaking, there are (1) an acrylic resin dispersed in an aqueous medium with a dispersant such as an emulsifier, and (2) an acrylic resin having a hydrophilic group dispersed in an aqueous medium.

  Examples of the acrylic resin aqueous dispersion dispersed in an aqueous medium with a dispersant such as the emulsifier of (1) above include, for example, an acrylic resin emulsion, and a conventional acrylic monomer emulsified in an aqueous medium in the presence of an emulsifier. The thing obtained by superposition | polymerization is mentioned.

  Examples of acrylic monomers include (meth) acrylic acid and alkali metal salts thereof, various esters of (meth) acrylic acid, (meth) acrylonitrile, N, N-dimethyl (meth) acrylamide, and 2-hydroxyethyl. (Meth) acrylate, 3- (meth) acryloylpropyltrimethoxysilane, 2-dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, and the like. Further, if necessary, vinyl monomers other than acrylic monomers can be used.

  Examples of the emulsifier that can be used for emulsion polymerization include nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polyoxypropylene copolymer, alkyl sulfate ester salts, and alkylbenzene. Anionic emulsifiers such as sulfonates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates, and cationic emulsifiers such as quaternary ammonium salts. The emulsifier is preferably used in the range of 0.1 to 10% by weight based on the total weight of the monomers, and further from the viewpoint of the shielding property of the aqueous primer composition of the present invention, 0.1 to 5% by weight. Is preferred.

  Of the emulsion polymerization methods, the radical emulsion polymerization method using a radical polymerization initiator is particularly simple. Examples of the radical polymerization initiator used at this time include persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azo. Azo compounds such as bisisobutyrate, organic peroxides such as benzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, and organic peroxides such as cumene hydroperoxide and iron oxide Examples include redox initiators in combination with a reducing agent. The amount of these radical initiators used is usually about 0.01 to 5% by weight, preferably about 0.05 to 2% by weight, based on the total weight of the monomers.

  In addition to the acrylic monomer, the emulsifier and the radical polymerization initiator, various chain transfer agents, pH adjusters and the like may be used in combination, as necessary, in 100 to 500% by weight of the total weight of the monomers. Thus, the target acrylic resin emulsion can be obtained by carrying out emulsion polymerization in a temperature range of 5 to 100 ° C., preferably 50 to 90 ° C., for 0.1 to 10 hours.

  Among the acrylic resin aqueous dispersion (D) used in the present invention, the acrylic resin aqueous dispersion in which the acrylic resin having a hydrophilic group (2) is dispersed in an aqueous medium is an aqueous acrylic resin having a hydrophilic group. It can be obtained by dispersing in a medium.

  The acrylic resin having a hydrophilic group has a hydrophilic group such as an anionic group, a cationic group, or a nonionic group.

  Examples of the anionic group include a carboxyl group, a phosphoric acid group, an acidic phosphate ester group, a phosphorous acid group, a sulfonic acid group, a sulfinic acid group, and the like, which are neutralized with a basic compound. preferable.

  Examples of basic compounds that can be used for neutralizing the anionic group include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, 2-aminoethanol, 2-dimethylaminoethanol, ammonia, sodium hydroxide, Examples include potassium hydroxide, tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, and trimethylbenzylammonium hydroxide.

  Examples of the cationic group include a primary amino group, a secondary amino group, a tertiary amino group, and an ammonium hydroxide group, and those obtained by neutralizing these with an acidic compound are preferable.

  Examples of the acidic compound include formic acid, acetic acid, propionic acid, lactic acid, phosphoric acid monomethyl ester, methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid, and nitric acid.

  Examples of nonionic groups include those having a polyether chain such as polyoxyethylene and polyoxypropylene.

  The acrylic resin having a hydrophilic group can be produced, for example, by polymerizing an acrylic monomer having a hydrophilic group.

  Examples of the acrylic monomer having a hydrophilic group include various carboxyl group-containing acrylic monomers such as (meth) acrylic acid and 2-carboxyethyl (meth) acrylate, alkali metal salts thereof, and the like. -Various tertiary amino group-containing (meth) acrylamides such as dimethyl (meth) acrylamide, various tertiary amino group-containing (meth) acrylic esters such as dimethylaminoethyl (meth) acrylate, and quaternized products thereof Of these, (meth) acrylic acid or dimethylaminoethyl (meth) acrylate is preferable. These can be used alone or in combination of two or more.

  Examples of the method for preparing an acrylic resin having a hydrophilic group using the monomer include various known and conventional polymerization methods. Among them, the solution radical polymerization method using an organic solvent is the simplest. is there. Examples of the organic solvent used here include aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, n-octane, cyclohexane and cyclopentane; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; Esters such as ethyl acetate, n-butyl acetate, n-amyl acetate, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate; methanol, ethanol, iso-propanol, n-butanol, iso- Butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n-butyl ether, propylene glycol monomethyl ether, propylene glycol mono-n Alcohols such as propyl ether and diethylene glycol monobutyl ether; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-amyl ketone and cyclohexanone; dimethoxyethane, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol Examples include ethers such as dibutyl ether; N-methylpyrrolidone, dimethylformamide, dimethylacetamide, ethylene carbonate, and the like. These can be used alone or in combination of two or more.

  In addition, as the radical polymerization initiator used in the solution radical polymerization method, various known and commonly used compounds can be used. Of these, only typical ones are illustrated as examples. Various azo compounds such as' -azobis (isobutylnitryl), 2,2'-azobis (2,4-dimethylvaleronitrile); tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl There are various peroxides such as peroxy-2-ethylhexanoate.

  In addition to the acrylic monomer having a hydrophilic group as described above, an acrylic monomer copolymerizable with them can be used in combination as required. Examples of typical acrylic monomers copolymerizable with the acrylic monomers include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meta ) Alkyl esters of (meth) acrylic acid such as acrylate.

  Preparation of the desired hydrophilic group-containing acrylic resin by applying a well-known and usual solution radical polymerization method using monomers, polymerization initiators and organic solvents as listed above can do.

  Examples of a method for dispersing the obtained hydrophilic group-containing acrylic resin in an aqueous medium include known and commonly used methods. Among them, it is preferable to disperse by a phase inversion emulsification method.

  The phase inversion emulsification method is a method in which the hydrophilic group of the acrylic resin is neutralized with a basic compound or an acidic compound, if necessary, and then dispersed in an aqueous medium.

  In the case where the hydrophilic group of the acrylic resin is a cationic group, a method of dissolving the acrylic resin in an organic solvent, neutralizing with the acidic compound, and then adding water is preferable.

  When the hydrophilic group of the acrylic resin is an anionic group, it is preferable to dissolve the acrylic resin in an organic solvent, neutralize with the basic compound, and then add water.

  In the phase inversion emulsification method, an emulsifier can be used as necessary within the range of achieving the object of the present invention.

  Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene copolymer, alkyl sulfate ester salt, alkylbenzene sulfonate, polyoxyethylene alkyl ether sulfate. Anionic emulsifiers such as ester salts and polyoxyethylene alkylphenyl ether sulfate esters, and cationic emulsifiers such as quaternary ammonium salts.

  Examples of the aqueous medium include water and water containing an organic solvent.

  As the organic solvent, those listed as organic solvents that can be used in the solution radical polymerization method can be used as they are, and esters, ketones, and ethers are particularly preferable. The organic solvent contained in the aqueous medium may be used alone or in combination of two or more, and the use ratio is preferably 1% by weight or more and 40% by weight or less in the aqueous medium, and is 1% by weight or more and 20% by weight or less. More preferably, the content is 1% by weight or more and 10% by weight or less.

  The acrylic resin aqueous dispersion thus obtained preferably has an acrylic resin solid content of 1 to 20% by weight.

  The acrylic resin of the acrylic resin aqueous dispersion (D) used in the present invention has a polystyrene equivalent weight average molecular weight measured by gel permeation chromatography of 350,000 or more, preferably 400,000 or more. From the viewpoint of safety and shielding properties.

  Since the acrylic resin of the acrylic resin aqueous dispersion (D) has a high molecular weight, it often does not dissolve in an organic solvent such as tetrahydrofuran (hereinafter abbreviated as THF). Most of such organic solvent insolubles such as THF are ultra high molecular weight components exceeding the detection limit and have a molecular weight of at least 500,000 in weight average molecular weight. Even if it is regarded as an ultra-high molecular weight component exceeding the detection limit, there is virtually no problem. Calculation of the amount of the molecular weight component in the present specification is also performed in such a manner.

The polystyrene-reduced molecular weight is measured under the following conditions using a general gel permeation chromatography analyzer.
Column temperature: 40 ° C
Solvent: THF
Flow velocity: 1.0 ml / min Detector: RI (differential refractive index detector)

In order to obtain the acrylic resin aqueous dispersion (D) satisfying this molecular weight condition, there is a method of reducing the number of radicals derived from the polymerization initiator relative to the vinyl monomer present in the polymerization system.
From this point of view, 1) a method for reducing the amount of polymerization initiator used, 2) a method for polymerization at low temperature, specifically (2a) 50% when an acrylic resin is dispersed in an aqueous medium with a dispersant such as an emulsifier. (2b) When an acrylic resin having a hydrophilic group is dispersed in an aqueous medium, polymerization is performed at a polymerization temperature of 80 ° C. or less. 3) Polymerization time Any of the methods for extending the length, or a combination of these methods is effective.

  Moreover, in order to obtain the acrylic resin aqueous dispersion (D) satisfying this molecular weight condition, a method of imparting a crosslinked structure is effective. The cross-linked structure here refers to a network structure that is chemically stable by bonding the main chains of the acrylic resin by chemical bonds.

  In order to obtain the acrylic resin aqueous dispersion (D) satisfying the molecular weight condition, the drying property of the aqueous primer composition of the present invention can be obtained by combining the method for reducing the number of radical generation and the method for imparting a crosslinked structure, It is preferable from the viewpoint of shielding properties.

  As a method for imparting a crosslinked structure, a method of copolymerizing a monomer having a plurality of polymerizable unsaturated bond groups in one molecule, a method of copolymerizing a silane coupling agent having a polymerizable unsaturated bond group, etc. Is mentioned.

  In the case of a method of copolymerizing a monomer having a plurality of polymerizable unsaturated bond groups in one molecule or a method of copolymerizing a silane coupling agent having a polymerizable unsaturated bond group, these monomers The body or the silane coupling agent is preferably 0.05 to 10 parts by weight per 100 parts by weight of the polymerizable unsaturated group-containing monomer from the viewpoints of drying and shielding properties of the aqueous primer composition of the present invention.

  Further, among the monomers having a plurality of polymerizable unsaturated bond groups in one molecule, the shielding property is lowered when the molecular chain between adjacent polymerizable unsaturated bond groups has a specific molecular weight. This is preferable because the drying property can be improved. Specifically, the molecular weight of the molecular chain between the polymerizable unsaturated bonding groups is preferably 100 or more, more preferably 100 to 700.

  As monomers having a plurality of polymerizable unsaturated bond groups in one molecule, diallyl phthalate, divinylbenzene, allyl acrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, Polyethylene glycol dimethacrylate (ethylene glycol skeleton number 4 or more), polypropylene glycol dimethacrylate (propylene glycol skeleton number 1 or more),

Neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 3-methyl 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonane Diol dimethacrylate, 2-methyl-1,8-octanediol dimethacrylate, 1,10-decanediol dimethacrylate, tricyclodecane dimethanol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, 2, 2-bis, 4- (methacryloxypolyethoxy) phenyl) propane (ethoxy skeleton number 2 or more), 2,4-diethyl-1,5-pentanediol dimethacrylate,

1,4-cyclohexanedimethanol dimethacrylate, polyethylene glycol diacrylate (ethylene glycol number 1 or more), polypropylene glycol diacrylate (propylene glycol number 1 or more), neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 1 , 9-nonanediol diacrylate, 3-methyl-1,5-pentanediol diacrylate, 2-methyl-1,8-octanediol diacrylate, tricyclodecane dimethanol diacrylate, 2-hydroxy 1-acryloxy-3- Methacryloxypropane, 2,2-bis (4-acryloxypolyethoxy) phenyl) propane (ethoxy number 1 or more), 2,2-hydrogenated bis (4- (acryloxypolyethoxy) phenyl) propane One or more ethoxy number),

Examples include 2,2-bis (4- (acryloxypolypropoxy) phenyl) propane (propoxy number 1 or more), 2,4-diethyl-1,5-pentanediol diacrylate, and the like. Two or more monomers having a polymerizable unsaturated bond group can be used in combination.

  Examples of the silane coupling agent having a polymerizable unsaturated bond group include unsaturated bond-containing silane compounds such as γ-methacryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane.

  Further, a monomer having a plurality of polymerizable unsaturated bond groups in one molecule and a silane coupling agent having a polymerizable unsaturated bond group may be used in combination.

  The acrylic resin of the acrylic resin aqueous dispersion (D) used in the present invention is required to have a glass transition temperature of 15 to 130 ° C. and 25 to 100 ° C. from the viewpoints of drying properties and shielding properties. Is preferred.

  The glass transition temperature (hereinafter referred to as Tg) of the acrylic resin in the acrylic resin aqueous dispersion (D) referred to in the present invention is based on a numerical value measured by a differential scanning calorimeter (hereinafter referred to as DSC).

  Furthermore, the acrylic resin of the acrylic resin aqueous dispersion (D) used in the present invention can use the above-mentioned acrylic monomers, and among them, a single amount containing an active hydrogen group that reacts with an isocyanate group. The body can be used. Examples of the active hydrogen-containing group that reacts with the isocyanate group include various known and commonly used groups, and representative examples thereof include a hydroxyl group, a carboxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, a sulfinic acid group, Examples include a mercapto group, a silanol group, an active methylene group, a carbamate group, a ureido group, a carboxylic acid amide group, and a sulfonic acid amide group. Of these, a hydroxyl group, an amino group, a carboxyl group and an active methylene group are preferred from the viewpoint of ease of introduction, and a hydroxyl group is particularly preferred. And these various active hydrogen containing groups may each be introduce | transduced independently, and 2 or more types may be introduce | transduced.

  As an acrylic monomer having a hydroxyl group, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxy Butyl (meth) acrylate, methyl (2-hydroxymethyl) acrylate, ethyl (2-hydroxymethyl) acrylate, butyl (2-hydroxymethyl) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate, glycerol mono (meta) ), Hydroxyl groups such as acrylate, phthalic acid mono (2-hydroxypropyl) -mono [2- (meth) acryloyloxy] ethyl ester, 2-hydroxy-3-phenoxypropyl (meth) acrylate (meta) Acrylic acid esters;

Examples thereof include mono (meth) acrylates of polyoxyalkylene glycol containing a hydroxyl group such as polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, and polybutylene glycol mono (meth) acrylate.
These monomers can be used alone or in combination of two or more.

  The hydroxyl value (mgKOH / g) of the acrylic resin in the acrylic resin aqueous dispersion (D) is preferably from 0 to 60, more preferably from 0 to 60, from the viewpoints of drying property and shielding property of the aqueous primer composition of the present invention. More preferably, it is 35.

  The acrylic resin in the acrylic resin aqueous dispersion (D) may be modified with a resin such as a silicon resin, a fluorine resin, a urethane resin, or an epoxy resin, if necessary, or these resins may be blended. It is.

  Acrylic resin aqueous dispersion (D) may be used as necessary in pigments, fillers, aggregates, dispersants, wetting agents, thickeners and / or rheology control agents, antifoaming agents, antiseptics, antifreezing agents, It is also possible to add a binder, a pH adjuster, a rust inhibitor, an ultraviolet absorber, an antioxidant and the like.

  Water-dispersed polyisocyanate (A), water (B), and cement (C) are mixed in any proportion and stirred to provide excellent drying of the primer accumulated in the recess and foaming of the urethane resin coating resin layer It is possible to obtain the aqueous primer composition of the present invention that is excellent in adhesion to an inorganic substrate and excellent in the effect of preventing swelling of the coating resin layer.

  By further adding the acrylic resin aqueous dispersion (D) at an arbitrary ratio to the aqueous primer, the effect of preventing the swelling of the coating resin layer can be further improved.

  The weight ratio of the water-dispersed polyisocyanate (A) and the acrylic resin water dispersion (D) is 100: 0 to 15:85 in terms of solid content, where the water-dispersed polyisocyanate (A) / acrylic resin water dispersion (D) is 100: 0 to 15:85. It is preferable that Furthermore, from the viewpoint of adhesiveness to an inorganic base material, drying property, and the effect of preventing swelling of the coating resin layer, (A) :( D) = 100: 0 to 50:50 is more preferable, and (A): (D) = 100: 0 to 55:45 is more preferable.

  There are no particular restrictions on the method of mixing the water-dispersible polyisocyanate (A), water (B), cement (C), and acrylic resin aqueous dispersion (D), and they can be mixed in any method and order.

  About the mixing method of water-dispersed polyisocyanate (A), water (B), cement (C), and acrylic resin water dispersion (D), well-known and usual stirring methods, such as a hand stirring with a stirring rod, a hand mixer, etc. Can be used.

  The ground treatment method using the aqueous primer composition of the present invention is a method of treating the inorganic base material surface of a civil engineering building by applying the aqueous primer composition to the inorganic base material of the civil engineering building by means of spraying, brushing or the like. is there.

The coating amount of the aqueous primer composition used for the base treatment varies depending on the type of inorganic base material constituting the base, but 0.1 to 1.0 kg per 1 m ² is used for porous materials such as concrete and mortar. It is done. Furthermore, it is preferable to apply 7 to 45 g of the aqueous primer composition per 1 m ^{2 in} terms of solid content to the inorganic base material from the viewpoints of adhesion to the inorganic base material, drying properties, and the effect of preventing the bulging of the coating resin layer.

  The laminated structure of the present invention includes at least three layers of an inorganic base material layer, a resin layer made of the above aqueous primer composition, and a coating resin layer made of any one of an epoxy resin, a urethane resin, and a polymerizable unsaturated resin. It is the laminated structure comprised from these.

  An example of such a commercially available epoxy resin is Chemicrete E (general-purpose epoxy resin: manufactured by ABC Shokai).

  The urethane resin is a commercially available product, Priadec HF-3500 [Hard urethane resin comprising natural oil and / or its derivative, and polyisocyanate compound: manufactured by Dainippon Ink & Chemicals, Inc.], Priadec PF-570 / General-purpose urethane resin using reaction of E-570 [prepolymer added with TDI and active hydrogen compound (PPG or / and 4,4′-diamino-3,3′-dichlorodiphenylmethane (MBOCA)): Dainippon Ink Chemical Industry Co., Ltd.].

  Examples of the polymerizable unsaturated resin include a polymerizable resin selected from urethane (meth) acrylate resin, epoxy (meth) acrylate resin, and polyester (meth) acrylate resin and / or α, β-unsaturated dibasic acid. Examples thereof include unsaturated polyester resins obtained by condensation reaction of dibasic acids and polyhydric alcohols, and those obtained by using radically polymerizable unsaturated group-containing monomers as essential components. Examples of these commercially available products include Diover HTP-563 [polymerizable resin: Dainippon Ink & Chemicals, Inc.] and Polylite FR-200 [Unsaturated polyester resin: manufactured by Dainippon Ink & Chemicals, Inc.]. .

  Examples of the inorganic base material include cement, which is generally used in construction such as concrete and mortar, civil engineering, and the like. In particular, since the aqueous primer composition of the present invention is excellent in drying properties, it is suitable for on-site construction use, and a concrete of a casing is preferably applied as an inorganic base material.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples. In the text, “parts” indicates parts by weight.

Reference Example 1 [Preparation of active hydrogen group-containing vinyl polymer (q-1)]
429 parts of diethylene glycol diethyl ether (hereinafter referred to as EDE) was charged into a four-necked flask equipped with a stirrer, thermometer, cooling pipe, and nitrogen introduction pipe, heated to 110 ° C. in a nitrogen stream, and then methoxypolyethylene glycol methacrylate 500 parts (containing 9 average oxyethylene units per molecule, hereinafter referred to as “MPEGMA-1”), 300 parts of methyl methacrylate (hereinafter referred to as MMA), 50 parts of 2-hydroxyethyl methacrylate (hereinafter referred to as 2-HEMA) A mixed solution consisting of 150 parts of cyclohexyl methacrylate (hereinafter referred to as CHMA), 45 parts of t-butylperoxy-2-ethylhexanoate and 5 parts of t-butylperoxybenzoate was added dropwise over 5 hours. After the dropwise addition, the mixture was reacted at 110 ° C. for 9 hours to obtain an acrylic polymer solution having a nonvolatile content of 70%. Hereinafter, this is referred to as an active hydrogen group-containing vinyl polymer (q-1).

Reference Example 2 [Preparation of water-dispersible polyisocyanate (a-1)]
In the same reactor as in Reference Example 1, Bernock DN-980S [HDI-based isocyanurate-type hydrophobic polyisocyanate isocyanate group content (hereinafter referred to as NCO group content), 21%, average NCO functional group number of about 3.6, Non-volatile content 100% Dainippon Ink & Chemicals, Inc.] 200 parts and active hydrogen group-containing vinyl polymer (q-1) 100 parts were charged, heated to 90 ° C. under a nitrogen stream, and then heated to 6 at the same temperature. The reaction was carried out with stirring for a time to obtain a water-dispersible polyisocyanate composition having a non-volatile content of 90% and an NCO group content of 13%. Hereinafter, this is called a polyisocyanate composition (a-1).

Reference Example 3 [Preparation of Acrylic Resin Aqueous Dispersion (d-1)]
In the same reactor as in Reference Example 1, 400 parts of deionized water and 7 parts of New Coal 707SF (30% solid anionic emulsifier manufactured by Nippon Emulsifier Co., Ltd.) were added, stirring was started, and the temperature was raised to 80 ° C. did. While adding 0.35 part of sodium persulfate and maintaining the reaction temperature at 78 ° C. to 80 ° C., 70 parts of deionized water prepared separately, 17.5 parts of New Coal 707SF, butyl acrylate (hereinafter referred to as BA) 122. 5 parts, 217 parts of MMA, 0.5 parts of methacrylic acid (hereinafter referred to as MAA), 3.5 parts of methacryloxytrimethoxysilane (hereinafter referred to as MTMS) with stirring and emulsification, and sodium persulfate 0.35 A mixture of 5 parts and 7 parts deionized water was added dropwise separately over 3 hours. While maintaining the same temperature, a mixture of 0.35 part of sodium persulfate and 28 parts of deionized water was added, and further kept at the same temperature for 4 hours, and then cooled to room temperature. The pH was adjusted to 7.5 using 25% aqueous ammonia, and an acrylic resin aqueous dispersion (d-0) having a nonvolatile content of 50% by weight, a weight average molecular weight of 500,000 or more, and Tg = 45 ° C. was obtained. .

Reference Example 4 [Preparation of Acrylic Resin Aqueous Dispersion (d-2)]
In the same reactor as in Reference Example 1, 400 parts of deionized exchange water and 7 parts of New Coal 707SF were charged, stirring was started, and the temperature was raised to 80 ° C. 0.70 part of sodium persulfate was charged, and 70 parts of deionized exchange water prepared separately, 17.5 parts of New Coal 707SF, 121.1 parts of BA, MMA 218.4 while maintaining the reaction temperature at 78 ° C to 80 ° C. And a monomer mixture obtained by stirring and emulsifying 10.5 parts of MAA and 3.5 parts of lauryl mercaptan, and a mixture of 0.70 parts of sodium persulfate and 7 parts of deionized water separately for 3 hours. It was dripped over. While maintaining the same temperature, a mixture of 0.70 parts of sodium persulfate and 28 parts of deionized water was added, and the mixture was further maintained at the same temperature for 4 hours, and then cooled to room temperature. The pH was adjusted to 7.5 using 25% aqueous ammonia to obtain an acrylic resin aqueous dispersion (d-2) having a nonvolatile content of 50% by weight, a weight average molecular weight of 240,000, and Tg = 45 ° C.

Reference Example 5 [Preparation of Acrylic Resin Aqueous Dispersion (d-3)]
In the same reactor as in Reference Example 1, 400 parts of deionized exchange water and 7 parts of New Coal 707SF were charged, stirring was started, and the temperature was raised to 80 ° C. Sodium persulfate (0.35 parts) was charged, and while maintaining the reaction temperature at 78 ° C. to 80 ° C., 70 parts of deionized water prepared separately, 17.5 parts of New Coal 707SF, 178.5 parts of BA, MMA 161.0 And a monomer mixture obtained by stirring and emulsifying 10.5 parts of MAA and 3.5 parts of MTMS, and a mixture of 0.35 part of sodium persulfate and 7 parts of deionized water separately over 3 hours. And dripped. While maintaining the same temperature, a mixture of 0.35 part of sodium persulfate and 28 parts of deionized water was added, and further kept at the same temperature for 4 hours, and then cooled to room temperature. The pH was adjusted to 7.5 using 25% aqueous ammonia to obtain an acrylic resin aqueous dispersion (d-3) having a nonvolatile content of 50% by weight, a weight average molecular weight of 500,000 or more, and Tg = 10 ° C. .

Examples 1-5 and Comparative Examples 1-5
The primer composition was obtained by mixing the water-dispersible polyisocyanate obtained in Reference Example, an acrylic resin aqueous dispersion, water, and cement. A laminated structure was produced using this primer composition, and the adhesion and swelling resistance tests were performed on this laminated structure.
Base material layer: concrete plate for pavement (thickness 60 × 300 × 300 mm).
Coating resin layer: After applying and drying the primer composition on the above concrete flat plate, a reinforcing dick cloth [Glass cloth: manufactured by Dainippon Ink & Chemicals, Inc.] is laid, and Priadec HF-3500 is used as a coating resin layer. [Rigid urethane resin: manufactured by Dainippon Ink & Chemicals, Inc.] was applied to a thickness of 2 mm according to a normal formulation and cured for 7 days under conditions of a temperature of 23 ° C. and a humidity of 50%.

<Evaluation method for pot life>
The time from when the primer was prepared until the primer started to gel was measured.
○: When it exceeds 30 minutes Δ: When it is 20 minutes to 30 minutes ×: When it is less than 20 minutes

<Recess drying evaluation method>
A concrete pavement board was provided with a 1 mm deep recess, the primer was filled up to the upper side of the recess when the primer was applied, and the time until tack free of that portion was measured.
Tack-free refers to the absence of tackiness, and the time until tack-free is measured by measuring the time it takes from applying the primer until it no longer adheres to the fingertips even after touching the applied primer surface. ,Obtained.
○: Less than 4 hours ×: More than 4 hours

<Method for evaluating foaming degree of coating resin layer>
The coating resin layer is peeled off from the inorganic substrate, the coating resin layer is cut with a cutter knife, the cross section is observed with a digital microscope (manufactured by Keyence Corporation), and the ratio of the area of the foamed portion in the cross sectional area is measured. did.
◎: 0% or more and less than 5% ○: 5% or more and less than 10% ×: 10% or more <Friction resistance test method>
The test specimen is immersed in room temperature water for a half hour, left to stand for 16 hours, and then subjected to 7 cycles of 60 ° C. warm water for 8 hours and room temperature water for 16 hours, and the ratio of the swelling area generated on the surface of the coated resin layer. Evaluation was carried out by calculating.
When the percentage of the blister area is less than 5%, ◎ when it is 5% or more and less than 20%, △ when it is 20% or more and less than 45%, Δ when it is 45% or more and less than 60%, Δ˜ ×, 60% The above case was evaluated as x.

<Tensile bond strength test method>
Four hours after the primer application, a laminate structure obtained by applying a coating resin layer and curing it was used as a test body, and an adhesion test was performed by the following uniaxial tensile adhesion test.
The surface of the coating resin layer is polished well with sandpaper or the like in advance, and a 40 × 40 mm steel jig is bonded to the surface of the coating resin layer with an epoxy adhesive. After the adhesive has hardened, cut along the jig until the base material is reached with a diamond cutter. A steel jig is attached to a uniaxial tensile testing machine (manufactured by Motofuji Co., Ltd.), and loading is carried out until it breaks at a test environment temperature of 23 ° C. and a loading speed of 1 kgf / cm ² / sec.
The adhesive strength is expressed by the following formula.
Tensile bond strength (N / mm2) = adhesive force (N) / bonded area (mm ²⁾
The evaluation was performed by visual observation of the tensile adhesive strength and the material breakage state.
The test results are shown in Table-1 and Table-2.

  In the table, component (A) is a water-dispersible polyisocyanate, and component (D) is an acrylic resin aqueous dispersion. The same applies hereinafter

  In Comparative Examples 1 and 2, since the cement was not contained, the drying of the recesses was poor and the rapid construction was not possible, the foaming of the coating resin layer was generated, and the swelling resistance was inferior. In Comparative Example 3, since the amount of cement was small, it was difficult to disperse the cement, and the drying of the recesses was poor, so that rapid construction could not be performed, and foaming of the coating resin layer occurred. Further, Comparative Example 4 had a large amount of cement and gelled within 5 minutes, so that it could not be used as a primer. In Comparative Example 5, since early strong Portland cement was used as the cement, the reactivity was fast, and gelation occurred within 5 minutes, making it impossible to use as a primer.

The water-based primer composition of the present invention can reduce the bromide and speed of the base treatment process, and is excellent in adhesion to an inorganic base material, anti-dandruffing effect and drying property of the coating resin layer, so that the roof, wall, floor, It is useful for the ground treatment of various inorganic base materials for civil engineering and construction such as roads, and since it is possible to provide a highly reliable laminated structure, it is industrially useful.

Claims (8)

An aqueous primer composition comprising water-dispersible polyisocyanate (A), water (B) and cement (C) as essential components. The aqueous primer composition according to claim 1, further comprising an acrylic resin aqueous dispersion (D). The acrylic resin of the acrylic resin aqueous dispersion (D) has a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography of 350,000 or more, and a glass transition measured by a differential scanning calorimeter of the acrylic resin. Temperature is 15-130 degreeC, and the weight ratio of the said water dispersible polyisocyanate (A) and the said acrylic resin water dispersion (D) is (A) :( D) = 100: 0 in conversion of solid content. The aqueous primer composition according to claim 2, which is 50:50. The aqueous primer composition according to claim 2 or 3, wherein the acrylic resin of the acrylic resin aqueous dispersion (D) is an acrylic resin having a hydroxyl value of 0 to 60. The aqueous primer composition according to any one of claims 1 to 4, wherein the cement (C) is ordinary Portland cement as defined in JIS R 5210. The cement (C) is 30 to 300 parts by weight with respect to 100 parts by weight of the total solid content of the solid content in the water-dispersible polyisocyanate (A) and the solid content in the acrylic resin aqueous dispersion (D). The aqueous primer composition according to any one of claims 2 to 5. A method for ground treatment of an inorganic substrate, wherein the aqueous primer composition according to any one of claims 1 to 6 is applied to an inorganic substrate of a civil engineering building. An inorganic base material layer for civil engineering buildings, a resin layer comprising the aqueous primer composition according to any one of claims 1 to 6, and an epoxy resin, a urethane resin or a polymerizable unsaturated resin on the resin layer. A laminated structure comprising at least three coating resin layers selected from the above resins.