JP4983118B2 - Water-based paint for floor and floor coating method - Google Patents

Description

  The present invention relates to an aqueous floor paint excellent in adhesion to an old paint film and a coating method thereof.

  Conventionally, various resin paints such as epoxy resin, urethane resin, polyester resin, and acrylic resin have been used for floor paints. When these floors are renovated, they are often applied directly to the old paint film without performing surface treatment such as exfoliation of the old paint film on which the paint film has deteriorated or primer coating.

  On the other hand, from the viewpoint of environmental problems, there is a strong demand to reduce the content of volatile organic solvents contained in floor paints. In order to meet this requirement, attempts have been made to make floor coatings water-based, and in particular, an organic solvent system comprising a polyisocyanate composition, which is the main curing composition of floor coatings, and an organic solvent-based resin having an active hydrogen-containing group. An aqueous solution of the curable composition is expected. For example, according to an aqueous curable composition comprising a polyisocyanate and a hydroxyl group-containing aqueous resin, or an aqueous paint comprising the cured product, hardness, appearance, water resistance, solvent resistance, old film adhesion It is reported that a water-based paint excellent in water resistance can be provided (see, for example, Patent Document 1).

  Further, the hydroxyl group-containing aqueous resin (A) having a number average molecular weight of less than 15,000 (A) is 5 to 50% by weight (based on solid content), and the hydroxyl group-containing aqueous resin (B) having a number average molecular weight of 15,000 or more is 50 to 95% by weight ( (Based on solid content) and an aqueous coating composition comprising the water-dispersible polyisocyanate composition (C) are excellent in appearance and water resistance, and are coated, and the coating portion is not deteriorated. It has been reported that even advanced substrates can be used (see, for example, Patent Document 2). In addition, in Patent Document 2, as Example 2, a hydroxyl group-containing acrylic resin emulsion having a solid content hydroxyl value of 60 mgKOH / g, a number average molecular weight of 10,000, a weight average molecular weight of 25,000, and a nonvolatile content of 50% by weight (A- 2) 150 parts by weight of a hydroxyl group-containing acrylic resin emulsion (B-2) having a solid content hydroxyl value of 20 mg KOH / g, a number average molecular weight of 500,000, a weight average molecular weight of 980,000, and a nonvolatile content of 40% by weight, An aqueous coating composition comprising 31.1 parts by weight of an aqueous polyisocyanate composition (C-1-3) is disclosed.

  In the case of water-based paint for floors, not only coating film properties such as hardness, appearance, water resistance, and solvent resistance, but also adhesion to various old coating films are important coating film properties. In addition, not only the hardness after about one week has passed since the coating, but also a so-called initial hardness that enables walking in a relatively short time such as several hours or the next day after coating. However, the water-based paint using the water-based curable composition described in Patent Document 1 does not have sufficient initial hardness, and the adhesion to the old coating film is water-based paint using the water-based curable composition. Although it is comparatively excellent with respect to the old paint film which deteriorated the paint film which consists of, it is not enough with respect to various other old paint films.

  In addition, in the aqueous paint using the aqueous resin composition described in Patent Document 2, particularly in the aqueous paint composition described in Example 2, a hydroxyl group having a solid content hydroxyl value of 20 mgKOH / g or more is relatively high. Since the high acrylic resin emulsion (B-2) is used, the initial hardness after coating is excellent, but the adhesion and water resistance to various old paint films are not sufficient.

  The old paint film adhesion in floor paint is the ability of the paint film after coating to adhere to various paint films that have been painted and deteriorated, and is particularly important as a floor paint in the case of repairs. Is performance.

  Moreover, initial hardness shows the coating-film performance after coating, and should just be a state which can be walked at least the next day. Furthermore, the water resistance is a representative performance indicating the coating film performance, and it is desirable that no blisters are generated.

Japanese Patent Laying-Open No. 2005-200197 JP 2002-363504 A

  The subject of this invention is providing the floor coating method using this water paint for floors which was excellent in old paint film adhesion, and was excellent in the initial stage hardness of a paint film, and water resistance.

  As a result of diligent research in view of such a current situation, the present inventors have found that the water-based paint has an acrylic resin having a specific hydroxyl value and a molecular weight above a certain level, and has a hydroxyl value below a certain level. In combination with an acrylic resin having excellent old film adhesion, the initial hardness and water resistance are excellent, and the coating method using this floor-based water-based paint includes The present inventors have found that a method of coating and drying on a floor material on which a film is present is preferable, and have completed the present invention.

  That is, the present invention relates to a polyisocyanate (A), an acrylic resin (B) having a hydroxyl value of 40 to 150 mgKOH / g, an acrylic resin having a weight average molecular weight of 350,000 or more and a hydroxyl value of 0 to 15 mgKOH / g ( An object of the present invention is to provide a water base paint for floors characterized in that C) is dispersed in an aqueous medium.

  The present invention also provides a floor coating method characterized by coating the floor water-based paint on a floor material on which an old coating film exists and drying the floor paint.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based coating material for floors which is excellent in the old coating-film adhesiveness considered until now, and excellent in initial hardness and water resistance can be obtained. Moreover, according to this invention, the floor in which the coating film excellent in old coating-film adhesiveness and water resistance was formed can be formed efficiently with sufficient workability.

Hereinafter, the present invention will be described in more detail.
First, the polyisocyanate (A) used in the present invention will be described. Various polyisocyanates can be used as the polyisocyanate (A) used in the present invention. Representative examples of such polyisocyanate (A) include 1,4-tetramethylene diisocyanate, ethyl (2,6-diisocyanate) hexanoate, 1,6-hexamethylene diisocyanate, 1,12-dodecamethylene diisocyanate, Aliphatic diisocyanates such as 2,2,4- or 2,4,4-trimethylhexamethylene diisocyanate; 1,3,6-hexamethylene triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 2 Aliphatic triisocyanates such as isocyanate ethyl (2,6-diisocyanato) hexanoate; 1,3- or 1,4-bis (isocyanatomethylcyclohexane), 1,3- or 1,4-diisocyanate Cyclohexane, 3,5,5-trimethyl Cycloaliphatic diisocyanates such as (3-isocyanatomethyl) cyclohexyl isocyanate, dicyclohexylmethane-4,4′-diisocyanate, 2,5- or 2,6-diisocyanatomethylnorbornane; 2,5- or 2,6- Alicyclic triisocyanates such as 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 tolylene-2,6-diisocyanate, diphenylmethane-4,4'-diisocyanate, naphthalene-1,5-diisocyanate, diphenyl-4,4'-diisocyanate, 4 , 4'-diisocyanate-3,3'-dimethyldiphenyl, aromatic diisocyanates such as 3-methyl-diphenylmethane-4,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate; triphenylmethane triisocyanate, tris Aromatic triisocyanates such as (isocyanatophenyl) thiophosphate;

A polyisocyanate having a uretdione structure obtained by cyclizing and dimerizing the isocyanate groups of various diisocyanates or triisocyanates as described above; cyclizing and trimerizing the isocyanate groups of various diisocyanates or triisocyanates as described above. Polyisocyanate having an isocyanurate structure obtained by the above; polyisocyanate having a burette structure obtained by reacting various diisocyanates or triisocyanates with water as described above; and various diisocyanates or triisocyanates as described above with carbon dioxide And polyisocyanate having an oxadiazine trione structure obtained by reacting with polyisocyanate; a polyisocyanate having an allophanate structure.

  And among these, since the stability of the isocyanate group in water and the weather resistance of the coating film are excellent, aliphatic or alicyclic diisocyanate or triisocyanate, aralkylene diisocyanate, or from them Derived polyisocyanates are particularly preferred. Among these polyisocyanates, in order to obtain an aqueous floor coating excellent in weather resistance and durability, an isocyanurate type polyisocyanate, a polyisocyanate having a burette structure, a polyisocyanate having a uretdione structure, a polyisocyanate having an allophanate structure. It is preferable to use a tri- or higher functional polyisocyanate such as a polyisocyanate obtained by reacting an isocyanate or diisocyanate with a trihydric or higher polyhydric alcohol.

  Such polyisocyanate (A) may impart self-water dispersibility by introducing hydrophilic groups such as various nonionic groups, anionic groups, and cationic groups. Preference is given to nonionic groups and anionic groups. In addition, addition of a component capable of dispersing polyisocyanate (A) such as various emulsifiers in an aqueous medium, or polyisocyanate (B) or acrylic resin (C) described below as polyisocyanate (C) You may disperse | distribute polyisocyanate (A) in an aqueous medium by using what has the capability to carry out water dispersion of A), and mixing with these water dispersions. Furthermore, you may disperse | distribute polyisocyanate (A) in an aqueous medium with the combination of the said method.

  As the nonionic group to be introduced for imparting self-water dispersibility, various groups can be introduced. Preferably, the terminal is a polyoxyalkylene group blocked with an alkoxy group, and the terminal is an anionic group. A polyoxyalkylene group such as a polyoxyalkylene group. More preferably, it is a polyoxyalkylene group whose end is blocked with an alkoxy group, and representative examples thereof include a polyoxyalkylene group such as a polyoxyethylene group, a polyoxypropylene group or a polyoxybutylene group, a poly ( Oxyethylene-oxypropylene) group or the like, in which the above oxyalkylene moieties are randomly copolymerized, or different polyoxyalkylene groups such as polyoxyethylene-polyoxypropylene groups are combined in a block form, etc. Is mentioned. And as a typical thing of the alkoxy group used for terminal blockage, a methoxy group, an ethoxy group, a butoxy group etc. are mentioned.

  There are various types of anionic groups introduced for imparting self-water dispersibility, but an acid group neutralized with a basic compound is preferable. Representative examples of neutralized acid groups include, for example, sulfonate groups, sulfate ester bases, phosphate groups, phosphate ester bases, phosphonate groups, phosphonate ester bases, phosphinate groups, sulfinate groups, And carboxylate groups.

  Preferred among these anionic groups is at least one selected from the group consisting of sulfonate groups, sulfate ester bases, phosphate ester bases, phosphonate groups, phosphonate ester bases, and phosphinate groups, and in particular. Preference is given to sulfonate groups and sulfate ester bases.

  Examples of the basic compound used when converting to an anionic group as described above by neutralizing an acid group include, for example, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, 2-aminoethanol, Organic amines such as 2-dimethylaminoethanol; inorganic basic compounds such as ammonia, lithium hydroxide, sodium hydroxide, potassium hydroxide; tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide, trimethylbenzylammonium hydro And quaternary ammonium hydroxides such as oxide. Of these, inorganic basic compounds are particularly preferable.

  Examples of a method for imparting self-water dispersibility by introducing a hydrophilic group such as a nonionic group, an anionic group, or a cationic group into the polyisocyanate (A) include the isocyanate group of the polyisocyanate and the hydrophilic group. And a method in which active hydrogen of a compound having an active aqueous-containing group is reacted. When an active hydrogen is contained in the hydrophilic group, it may have an active hydrogen-containing group separately.

  Examples of the compound having both the hydrophilic group and the active water-containing group include polyethylene glycol, polyether diol having both oxyethylene units and oxypropylene units, various polyether diols containing oxyethylene units, and oxyethylene. Polyether diols having both a unit and an oxypropylene unit; polyether diols in which one end of the polyether diol is blocked with an alkoxyl group; polyether in which the polyether diol or one end is blocked with an alkoxyl group Examples thereof include polyether diols having an anionic group or a cationic group in diols; vinyl polymers having a hydrophilic group and an active hydrogen-containing group.

  Among these compounds having both a hydrophilic group and an active water-containing group, preferred are polyether diols having one end blocked with an alkoxyl group, a polyoxyethylene group having one end blocked with an alkoxyl group, and a hydroxyl group. Vinyl polymer.

  The emulsifier for dispersing the polyisocyanate (A) in an aqueous medium may be any one having a nonionic group, an anionic group, a cationic group, or the like. Examples of the nonionic group and the anionic group include those exemplified as the nonionic group and the anionic group for imparting self-water dispersibility to the polyisocyanate (A). Moreover, as a cationic group, a primary amino group, a secondary amino group, a tertiary amino group, an ammonium hydroxide group etc. are mentioned, for example, What neutralized these with the acidic compound is preferable. Furthermore, you may have multiple said nonionic group, anionic group, and cationic group.

  An emulsifier for dispersing the polyisocyanate (A) in an aqueous medium may be added to the polyisocyanate (A) as long as it does not react with the polyisocyanate (A). Moreover, you may mix with polyisocyanate (A) immediately before mixing with acrylic resin (B) and acrylic resin (C).

  As a method for dispersing the polyisocyanate (A) in an aqueous medium, (1) the polyisocyanate (A) or the polyisocyanate (A) added with an emulsifier is added to the aqueous medium and dispersed, and the resulting aqueous dispersion is obtained. The liquid is added to the acrylic resin (B) and acrylic resin (C) dispersed in water and mixed, (2) polyisocyanate (A) or polyisocyanate (A) added with an emulsifier is dispersed in water. Method of directly adding to acrylic resin (B) and acrylic resin (C), mixing and dispersing [However, when using isocyanate which does not have self-water dispersibility as polyisocyanate (A), water-dispersed acrylic As the resin (B) and the acrylic resin (C), it is necessary to use a resin capable of dispersing the polyisocyanate in water. ] Etc. are mentioned.

  Next, the acrylic resin (B) used in the present invention will be described.

  The acrylic resin (B) used in the present invention needs to have a hydroxyl value of 40 to 150 mgKOH / g. When the hydroxyl value is lower than 40, sufficient water resistance cannot be obtained. When the hydroxyl value is higher than 150, the hydroxyl group which is a hydrophilic group decreases water resistance. Especially, since the aqueous | water-based coating material for floors excellent in the water resistance of a coating film is obtained, it is preferable that the range of a hydroxyl value is 50-120 mgKOH / g, and it is more preferable that it is 60-100 mgKOH / g.

  The glass transition temperature (Tg) of the acryl-based resin (B) is not particularly limited. In particular, it is 15 to 70 ° C. because an aqueous paint for flooring excellent in old film adhesion and initial hardness can be obtained. Is preferable, and it is more preferable that it is 25-60 degreeC.

  The molecular weight of the acrylic resin (B) is not particularly limited. If the coating film can be formed, the molecular weight of the acrylic resin (B) is insoluble in tetrahydrofuran (THF) which is a developing solvent at the time of molecular weight measurement by gel permeation chromatography. It may contain components that are difficult to measure, but the content of THF-insoluble components at 25 ° C. is preferably less than 20% by weight, more preferably less than 5% by weight, and THF-insoluble. Most preferred are those containing no components. Among such acrylic resins (B), an aqueous coating for flooring excellent in old film adhesion and initial hardness can be obtained, so that it contains no THF-insoluble components and has a number average molecular weight of 10,000 to 100. Those having a weight average molecular weight of 30,000 to 1,000,000, those having a number average molecular weight of 20,000 to 100,000 and a weight average molecular weight of 50,000 to 1,000,000 Is more preferable.

  A component insoluble in THF, which is a developing solvent when measuring the molecular weight of an acrylic resin such as acrylic resin (B) by gel permeation chromatography, has a number average molecular weight of at least 100,000 and a weight average molecular weight of at least 500. , 000.

  The acrylic resin (B) can be produced, for example, by copolymerizing an acrylic monomer having a hydroxyl group or another acrylic monomer. At this time, if necessary, a vinyl monomer other than the acrylic monomer and a silane coupling agent having a vinyl group may be used in combination.

  Examples of the acrylic monomer having a hydroxyl group used for introducing a hydroxyl group into the acrylic resin (B) include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl. (Meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-n-butyl (meth) acrylate, 3-hydroxy-n-butyl (meth) acrylate, etc., among others, 2-hydroxyethyl (meta) ) Acrylate is preferred.

  Examples of other acrylic monomers include (meth) acrylic acid and alkali metal salts thereof, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, and cyclohexyl (meth) acrylate. Various esters of (meth) acrylic acid such as, acrylamide, N, N-dimethyl (meth) acrylamide, (meth) acrylonitrile, 3- (meth) acryloylpropyltrimethoxysilane, 2-dimethylaminoethyl (meth) Examples thereof include acrylic monomers such as acrylate and glycidyl (meth) acrylate.

  Furthermore, examples of vinyl monomers other than acrylic monomers include styrene and α-methylstyrene.

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

  The acrylic resin (B) is in a state of being dispersed in an aqueous medium in the aqueous coating composition for floors of the present invention, and various dispersion forms can be mentioned. Broadly speaking, (1) an acrylic resin (B1) dispersed in an aqueous medium with an emulsifier, (2) an acrylic resin (B2) having a hydrophilic group dispersed in an aqueous medium, etc. .

  As the acrylic resin (B1) dispersed in an aqueous medium with the emulsifier (1), for example, the acrylic resin (B1), the emulsifier and water are stirred to disperse the acrylic resin (B1) in water. And those obtained by emulsion polymerization of an acrylic monomer in an aqueous medium in the presence of an emulsifier.

  Examples of the emulsifier that can be used when the emulsifier is added to the acrylic resin (B1) and stirred and dispersed in water include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene polyoxypropylene copolymer Nonionic emulsifiers such as coalescents, anionic emulsifiers such as alkyl sulfate esters, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, and cationic emulsifiers such as quaternary ammonium salts Etc. The emulsifier is preferably used in an amount of 20 parts by weight or less with respect to 100 parts by weight of the monomer, and moreover, since a water-based floor paint excellent in water resistance is obtained, the range of 5 to 15 parts by weight is more preferable. preferable.

  In addition, as the emulsifier that can be used when the emulsion polymerization is performed, any of the nonionic emulsifiers, anionic emulsifiers, and cationic emulsifiers listed as emulsifiers that can be used when the acrylic resin (B1) is dispersed in water is used. it can. The emulsifier is preferably used in an amount of 10 parts by weight or less with respect to 100 parts by weight of the monomer. Further, since an aqueous floor paint having excellent water resistance is obtained, the range of 2 to 5 parts by weight is more preferable. preferable.

  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 in this case include persulfates such as potassium persulfate, sodium persulfate and ammonium persulfate, 2,2′-azobisisobutyronitrile, dimethyl-2,2′-azo. An azo compound such as bisisobutyrate, an organic peroxide such as benzoyl peroxide, tert-butylperoxy-2-ethylhexanoate, an organic peroxide such as cumene hydroperoxide, and a reducing agent such as iron oxide; Redox initiators based on the combination of The amount of these radical polymerization initiators used is usually 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of 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, if necessary, to 100 parts by weight based on 100 parts by weight of the total weight of the monomers. The target acrylic resin (B1) is obtained by carrying out emulsion polymerization for 0.1 to 10 hours in a temperature range of 5 to 100 ° C., preferably 50 to 90 ° C. in 500 parts by weight of water. Obtainable.

  Among the acrylic resins (B) used in the present invention, the acrylic resin (B2) having the hydrophilic group (2) dispersed in an aqueous medium includes, for example, an anionic group, a cationic group, What dispersed the acrylic resin which has hydrophilic groups, such as a nonionic group, in the aqueous medium is mentioned.

  Examples of the anionic group include a carboxyl group, a phosphoric acid group, an acidic phosphoric acid ester group, a phosphorous acid group, a sulfonic acid group, and a sulfinic acid group, and those obtained by neutralizing these with a basic compound are used. It is preferable.

  Examples of the basic compound 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 used for neutralizing the cationic group include formic acid, acetic acid, propionic acid, lactic acid, phosphoric acid monomethyl ester, methanesulfonic acid, benzenesulfonic acid, dodecylbenzenesulfonic acid, hydrochloric acid, sulfuric acid, Nitric acid etc. are mentioned.

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

  The acrylic resin (B2) having a hydrophilic group is, for example, as a part of other acrylic monomer in a production method in which an acrylic monomer having a hydroxyl group or another acrylic monomer is copolymerized. It can be produced by using an acrylic monomer having a hydrophilic group and polymerizing it together with an acrylic monomer having a hydroxyl group and other acrylic monomers.

  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, and alkali metal salts thereof. Various tertiary amino group-containing (meth) acrylamides such as N, dimethyl- (meth) acrylamide, and various tertiary amino group-containing (meth) acrylic acid esters such as dimethylaminoethyl (meth) acrylate and quaternized products thereof Among these, (meth) acrylic acid or dimethylaminoethyl (meth) acrylate is preferable among these. These can be used alone or in combination of two or more.

  Examples of the method for preparing the acrylic resin (B2) having a hydrophilic group using the acrylic monomer as described above include various polymerization methods, and among them, a solution radical using an organic solvent. The polymerization method is the simplest. 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- 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, Ethers such as diethylene glycol 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, various compounds can be used as the radical polymerization initiator used in the solution radical polymerization method described above. Of these, 2,2′-azobis ( Various azo compounds such as isobutyl nitryl), 2,2'-azobis (2,4-dimethylvaleronitrile); tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2 -There are various peroxides such as ethyl hexanoate.

  Using the monomers, polymerization initiators and organic solvents as described above, the target acrylic resin (B2) having a hydrophilic group is prepared by applying the solution radical polymerization method. can do.

  Various methods can be mentioned as a method of dispersing the obtained acrylic resin (B2) having a hydrophilic group in an aqueous medium, and among these, it is preferable to disperse by a phase inversion emulsification method.

  In the phase inversion emulsification method, an acrylic resin (B2) is mixed with an organic solvent solution of an acrylic resin (B2) obtained by neutralizing a hydrophilic group with a basic compound or an acidic compound as necessary. ) Is dispersed (transfer emulsified) in an aqueous medium, and the organic solvent is removed if necessary. In this case, an emulsifier can be used as necessary within the scope of achieving the object of the present invention.

  As the emulsifier, for example, any of the nonionic emulsifiers, anionic emulsifiers, and cationic emulsifiers listed as emulsifiers that can be used when the acrylic resin (B1) is dispersed in water can be used.

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 of the acrylic resin (B2) 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. The use ratio thereof is preferably 30% by weight or less in the aqueous medium, more preferably 15% by weight or less, and more preferably 5% by weight. More preferably, it is most preferably not used. In addition, it is preferable that the usage rate when using an organic solvent is 1 weight% or more.

  In order to obtain the acrylic resin (B) satisfying the above-mentioned number average molecular weight and weight average molecular weight, for example, an acrylic monomer having a hydroxyl group present in the polymerization system or other acrylic monomers (vinyl) In contrast, a method of polymerizing by lowering the number of radicals derived from the polymerization initiator, a method of imparting a crosslinked structure to the acrylic resin (B) at the time of polymerization, etc. Can be mentioned. 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.

  Examples of the method for reducing the number of radicals generated include any one of (1) a method for reducing the amount of a polymerization initiator used, (2) a method for polymerizing at a low temperature, and (3) a method for extending a polymerization time. Alternatively, a combination of these methods is effective. In addition, as a specific example of the method of (2) polymerization at a low temperature, for example, in the case of obtaining (A) an acrylic resin (B1) in which an acrylic resin is dispersed in an aqueous medium with a dispersant such as an emulsifier, In the case of obtaining an acrylic resin (B2) in which an acrylic resin having a hydrophilic group is dispersed in an aqueous medium by polymerization using a so-called redox initiator at the following polymerization temperature, polymerization at 80 ° C. or lower Examples include a method of polymerizing at a temperature.

  In order to effectively obtain the acrylic resin (B) satisfying the molecular weight condition, a method of polymerizing by reducing the number of radicals generated may be combined with a method of imparting a crosslinked structure.

  As a method for imparting a crosslinked structure to the acrylic resin (B), for example, it has a plurality of vinyl groups in one molecule as a part of other acrylic monomers used together with an acrylic monomer having a hydroxyl group. A method of copolymerizing monomers, a silane coupling agent having a vinyl group, an acrylic monomer having a hydroxyl group, and other acrylic monomers (a vinyl monomer may be used in combination). Examples thereof include a method of copolymerizing in combination. A monomer having a plurality of vinyl groups in one molecule and a silane coupling agent having a vinyl group can be used in combination. Since the use ratio of the monomer having a plurality of vinyl groups in one molecule and / or the silane coupling agent having a vinyl group, a water-based paint for flooring excellent in initial coating film hardness and water resistance can be obtained. Monomer component used for the synthesis of the acrylic resin (B) [for example, an acrylic monomer having a hydroxyl group, other acrylic monomers (including monomers having a plurality of vinyl groups in one molecule) A mixture of a vinyl monomer, a silane coupling agent having a vinyl group, and the like. )] It is preferably 1 part by weight or less per 100 parts by weight, more preferably 0.5 part by weight or less, and most preferably 0.1 part by weight or less.

  Further, among monomers having a plurality of vinyl groups in one molecule, the initial coating film hardness is such that the molecular weight of the molecular chain between adjacent vinyl groups is 100 or more, preferably 100-700. This is preferable because the water resistance can be improved without dropping the water content.

  Examples of monomers having a plurality of vinyl groups in one molecule include diallyl phthalate, divinyl benzene, allyl acrylate, trimethylol propane 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-nonanediol dimethyl Chlorate, 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 (ethoxy number 1 or more), 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 of these vinyl group-containing monomers may be used in combination.

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

  The acrylic resin (C) used in the present invention needs to have a polystyrene-equivalent weight average molecular weight of 350,000 or more as measured by gel permeation chromatography, but when measuring the molecular weight by gel permeation chromatography. May contain a component that is insoluble in tetrahydrofuran (THF), which is a developing solvent, and has a molecular weight that is difficult to measure. Among them, the content of the THF-insoluble component at 25 ° C. is less than 95% by weight. Preferably, it is less than 80% by weight, more preferably less than 60% by weight. When the weight average molecular weight is less than 350,000, the old coating film adhesion, initial coating film hardness, and water resistance are lowered. Especially, since the water-based paint for floors excellent in old film adhesion, initial film hardness, and water resistance is obtained, the weight average molecular weight is preferably 400,000 or more, and 500,000 or more. It is more preferable. Moreover, the number average molecular weight of the acrylic resin (C) is usually 80,000 or more, preferably 90,000 or more, more preferably 100,000 or more.

  The component insoluble in THF, which is a developing solvent when measuring the molecular weight of the acrylic resin (C) by gel permeation chromatography, also has a number average molecular weight of at least 100,000 as in the case of the acrylic resin (B). The weight average molecular weight can be regarded as at least 500,000.

  Further, the acrylic resin (C) used in the present invention needs to have a hydroxyl value of 0 to 15 mgKOH / g. When the hydroxyl value is higher than 15 mgKOH / g, the old coating film adhesion, initial coating film hardness, and water resistance are lowered. Especially, since the water-based paint for floors excellent in old paint film adhesion is obtained, it is preferable that the hydroxyl value of acrylic resin (C) is 0-12 mgKOH / g, and is 0-5 mgKOH / g. Is more preferable.

  Although the glass transition temperature (Tg) measured by the differential scanning calorimeter of the acrylic resin (C) is not particularly limited, an aqueous paint for flooring excellent in old film adhesion and initial hardness can be obtained. 30 to 75 ° C is preferable, and 40 to 65 ° C is more preferable.

  The acrylic resin (C) can be produced by, for example, using an acrylic monomer having a hydroxyl group or another acrylic monomer and copolymerizing under a condition that a high molecular weight acrylic resin is obtained. it can. At this time, if necessary, a vinyl monomer other than the acrylic monomer and a silane coupling agent having a vinyl group may be used in combination.

  Examples of the acrylic monomer having a hydroxyl group, other acrylic monomers, vinyl monomers other than acrylic monomers used as necessary, and silane coupling agents having a vinyl group include acrylic resins. Acrylic monomers having hydroxyl groups listed as monomers that can be used in the production of (B), other acrylic monomers, vinyl monomers other than acrylic monomers, and silane cups having vinyl groups Any ring agent can be used.

  Like the acrylic resin (B), the acrylic resin (C) is in a state of being dispersed in an aqueous medium in the aqueous paint for floors of the present invention, and its dispersion form is also that of the acrylic resin (B). As in the case, (1) Acrylic resin (C1) dispersed in an aqueous medium with a dispersant such as an emulsifier, (2) Acrylic resin (C2) having a hydrophilic group dispersed in an aqueous medium As the specific method of dispersing in an aqueous medium, any of the same methods as in the case of the acrylic resin (B) can be adopted.

  In order to obtain the acrylic resin (C) satisfying the above-described weight average molecular weight, preferably the acrylic resin (C) satisfying the number average molecular weight and the weight average molecular weight, all the methods described in the acrylic resin system (B) are used. Can be used. That is, radical generation derived from a polymerization initiator for an acrylic monomer having a hydroxyl group present in the polymerization system and other acrylic monomers (vinyl monomers may be used in combination). There are a method of polymerizing by reducing the number and a method of imparting a crosslinked structure to the acrylic resin (C) during the polymerization.

  Any of the methods (1) to (3) described in the acrylic resin system (B) can be used for reducing the number of radicals generated.

  In order to effectively obtain the acrylic resin (C) satisfying the molecular weight condition, it is possible to combine the method of polymerizing by lowering the number of radicals generated and the method of imparting a cross-linked structure. It is preferable because a water-based paint for floors having excellent properties can be obtained.

  As the method for imparting a crosslinked structure to the acrylic resin (C), any of the methods described in the acrylic resin system (B) can be used. However, the use ratio of the monomer having a plurality of vinyl groups and / or the silane coupling agent having a vinyl group in one molecule used in these methods is the water-based paint for floors excellent in initial coating film hardness and water resistance. Monomer component [for example, acrylic monomer having a hydroxyl group, other acrylic monomer (having a plurality of vinyl groups in one molecule). A monomer may be contained.), A mixture of a vinyl monomer, a silane coupling agent having a vinyl group, and the like. )] It is preferably 0.05 to 10 parts by weight per 100 parts by weight, more preferably 0.1 to 5 parts by weight, and most preferably 0.2 to 2 parts by weight.

  Also in the method of imparting a crosslinked structure to the acrylic resin (C), as in the case of the acrylic resin type (B), among the monomers having a plurality of vinyl groups in one molecule, adjacent vinyls It is preferable that the molecular weight of the molecular chain between the groups is 100 or more, preferably 100 to 700, since the water resistance can be improved without lowering the initial coating film hardness.

  Examples of the monomer having a plurality of vinyl groups in one molecule include any of the monomers having a plurality of vinyl groups in one molecule described in the method for imparting a crosslinked structure to the acrylic resin (C). Can be used as well.

  The weight ratio [(B) / (C)] of the acrylic resin (B) and the acrylic resin (C) used in the present invention is for flooring excellent in old film adhesion, initial film hardness, and water resistance. In order to obtain a water-based paint, it is preferably 0.3 to 3, more preferably 0.4 to 2.2, and most preferably 0.7 to 1.5.

Here, the glass transition temperature (Tg) of acrylic resins such as acrylic resins (B) and (C) used in the present invention is determined by the following method.
The numerical value obtained by converting the glass transition temperature (Tg _K ) expressed in the absolute temperature (K) calculated by the following Fox equation into the Celsius temperature (° C.) is defined as the glass transition temperature (Tg) in the present invention.
100 / Tg _K = W ₁ / Tg ₁ + W ₂ / Tg ₂ + W ₃ / Tg ₃ + W ₄ / Tg ₄ ...
- _{wherein, W 1, W 2, W} 3, W 4 ··· denotes the mass fraction of the various components (mass%).
- _wherein indicates a _{Tg 1, Tg 2, Tg 3} , Tg 4 ··· glass transition temperature of the absolute temperature (K) Display of the homopolymer of each monomer component. Here, the glass transition temperatures (Tg ₁ , Tg ₂ , Tg ₃ , Tg ₄ ...) Indicated by the absolute temperature (K) of the homopolymer of each of the above monomer components are determined by Polymer Handbook (Second Edition, J, Brandrup E. , H, edited by Immergut).

  The number average molecular weight and weight average molecular weight of acrylic resins such as acrylic resins (B) and (C) used in the present invention are the number average molecular weight and weight average molecular weight in terms of polystyrene measured by gel permeation chromatography. Yes, it is determined by the following method. However, since the acrylic resins (B) and (C) may be those containing some components that are insoluble in tetrahydrofuran (THF), which is a developing solvent at the time of molecular weight measurement, there are some cases where THF insoluble components are used. The molecular weight value of the acrylic resin contained in part is the molecular weight of only the part dissolved in THF.

  The number average molecular weight and the weight average molecular weight of the acrylic resin are measured using a gel permeation chromatography apparatus with a ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (Mw / Mn = dispersion degree) of 1. The molecular weight is assigned to the measured sample by a calibration curve created using 10 or more standard polystyrenes of 10 or less. The number average molecular weight and the weight average molecular weight (Mw) are calculated by the following formula. In general, the number average molecular weight and the weight average molecular weight are those detected by a data processor.

Number average molecular weight (Mn)
= W / ΣNi = Σ (Mi × Ni) / ΣNi = ΣHi / Σ (Hi / Mi)
Weight average molecular weight (Mw)
= Σ (Wi × Mi) / W = Σ (Hi × Mi) / ΣHi
In the formula, W: total weight of polymer Wi: weight of i-th polymer Mi: molecular weight at i-th elution time Ni: number of molecular weights Mi Hi: height at i-th elution time.

Moreover, the measuring apparatus and measurement conditions are as follows.
Measuring device Device: HLC-8120GPC manufactured by Tosoh Corporation
Column used: TSKgel G2000H _XL (column 1) manufactured by Tosoh Corporation
TSKgel G3000H _XL (column 2) manufactured by Tosoh Corporation
Tosoh Co., Ltd. TSKgel G4000H _XL (column 3)
Tosoh Co., Ltd. TSKgel G5000H _XL (column 4)
Tosoh Co., Ltd. TSKgel GMH _XL (Column 5)
Guard column H _XL- H (column 6) manufactured by Tosoh Corporation
Column connection:
In the case of a weight average molecular weight of 100,000 to 1,000,000: A column in which four (columns 5) are connected to (column 6) is used.
When the weight average molecular weight is 100,000 or less: Use one in which (Column 6), (Column 4), (Column 3), (Column 2), and (Column 1) are connected in this order.
Detector: RI (differential refractometer)
Data processing: Multi-station-8020 manufactured by Tosoh Corporation
Preparation of standard polystyrene: 10 mg of each standard polystyrene is weighed and dissolved in 100 ml of tetrahydrofuran (THF). Dissolution is performed at 20 ° C. and used after standing for 24 hours.
Preparation of sample: 80 mg of sample (solid content) is weighed and dissolved in 20 ml of THF.

Measurement conditions Column temperature: 40 ° C
Solvent: tetrahydrofuran (THF)
Flow rate: 1 ml / min Sample injection volume: 100 μl

  The floor water-based paint of the present invention can be used as a clear paint containing no pigment, or it can be used as a colored paint by blending various known organic or inorganic pigments. For the acrylic resin (B) and acrylic resin (C) used in the present invention, for example, a filler, a leveling agent, a thickener, an antifoaming agent, an organic solvent, an ultraviolet absorber, an oxidation agent are used as necessary. Various additives such as an inhibitor and a pigment dispersant can also be blended.

  Typical pigments used in preparing colored paints include organic pigments such as carbon black, phthalocyanine blue, phthalocyanine green, quinacridone red, etc .; titanium oxide, iron oxide, titanium yellow, copper Examples thereof include metal oxide inorganic pigments such as chromium black; extender pigments such as calcium carbonate, clay, talc, and barium sulfate; inorganic flake pigments such as aluminum flakes and pearl mica.

  When preparing a colored paint using the various pigments described above, the total amount of solids of polyisocyanate (A) and solids of acrylic resin (B) and acrylic resin (C) is 100 parts by weight. The pigment may be blended at a ratio such that the pigment is 0.1 to 300 parts by weight, preferably 0.2 to 200 parts by weight.

  Typical examples of the ultraviolet absorber added in the preparation of the water-based floor coating composition of the present invention include various compounds such as benzotriazole compounds, oxalic acid anilide compounds, and hydroxybenzophenone compounds. Examples of the antioxidant to be added include hindered amine compounds, hindered phenol compounds, and phosphorus compounds. And the addition amount in the case of adding these is a ultraviolet absorber with respect to 100 weight part of total amounts of solid content of polyisocyanate (A) and solid content of acrylic resin (B) and acrylic resin (C). And / or an antioxidant should just mix | blend in the ratio which becomes 0.2-10 weight part, Preferably, it is 0.5-5 weight part.

  The floor water-based paint of the present invention is obtained by dispersing the polyisocyanate (A), the acrylic resin (B), and the acrylic resin (C) in an aqueous medium. Examples of the method of mixing A) with the acrylic resin (B) and the acrylic resin (C) include, for example, polyisocyanate (B) and acrylic resin (C) dispersed in an aqueous medium. A) Or the method of adding and stirring what the polyisocyanate (A) disperse | distributed in the aqueous medium is mentioned. As a stirring method, for example, there is a method of using various stirrers, and if it is a small amount, simple stirring using a stirrer or the like may be used. It is preferable because a paint can be prepared. Moreover, when polyisocyanate (A) does not have self-water dispersibility, it is preferable to use various stirrers having a strong shearing force, such as a jet mill.

  Since the mixing ratio of the polyisocyanate (A) and the acrylic resin (B) and the acrylic resin (C) at this time is an old paint film adhesion, initial hardness, water-based paint for flooring excellent in water resistance, The molar ratio (NCO / OH) of the isocyanate group in the polyisocyanate (A) and the hydroxyl group in the acrylic resin (B) and the acrylic resin (C) is preferably 0.5 to 2.5, 0 0.7 to 1.5 is more preferable, and 0.9 to 1.3 is most preferable.

  The water-based paint for floors of the present invention can be directly applied onto a so-called old paint film that has been deteriorated by applying various paints. Moreover, it can apply | coat directly on a flooring and can also apply | coat on the flooring which applied various primers. Furthermore, after applying and drying the water-based paint for floors of the present invention, the water-based paint for floors of the present invention can be applied again and dried.

  Various flooring materials can be used as the flooring water-based paint of the present invention, and examples thereof include various inorganic flooring materials, wooden flooring materials, plastic flooring materials, etc., among which inorganic flooring materials. Is preferred.

  As the inorganic flooring, for example, a cured product produced from a calcium compound such as calcium silicate, calcium aluminate, calcium sulfate, calcium oxide; ceramic obtained by sintering a metal oxide such as alumina, silica, zirconia; Tiles obtained by firing various clay minerals; various glasses and the like. Representative examples of hardened bodies produced from calcium compounds include hardened cement compositions such as concrete and mortar, asbestos slate, lightweight aerated concrete (ALC) hardened bodies, dolomite plaster hardened bodies, and plaster plaster hardened. Body, calcium silicate plate and the like.

  Examples of the wood floor material include solid wood, laminated wood, veneered decorative plywood, decorative paper-laminated plywood, medium-quality fiberboard, particle board, and those obtained by treating these with WPC (Wood Plastic Combination). Although there is no restriction | limiting in particular as a kind of tree, Generally coniferous materials, such as a cedar, a pine, a cypress, and a larch, Hardwood materials, such as a hippopotamus, a zelkova, a Mizunara, a cherry tree, a walnut, a rose, a teak, and a mahogany, are mentioned.

  Examples of plastic floor materials include molded products of thermoplastic resins such as polystyrene, polycarbonate, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride, polypropylene, polybutylene terephthalate, or polyethylene terephthalate; unsaturated polyester Examples thereof include molded products of thermosetting resins such as resins, phenol resins, cross-linked polyurethane, cross-linked acrylic resins or cross-linked saturated polyester resins.

  Further, even if the various flooring materials as described above are coated, and the flooring material in which the coating part has deteriorated, that is, the so-called old coating film remains, It can be used as a flooring in the invention.

  Examples of the old paint film include various floor paints such as epoxy resin paints, urethane resin paints, polyester paints, and acrylic resin paints.

  Various primers are used, but typical one-component moisture-curing urethane primer, two-component bisphenol A epoxy / polyamine primer, unsaturated polyester primer, vinyl ester primer , Acrylic primer, rubber primer, aqueous two-component curable polyurethane primer, and the like.

  Examples of the method for coating the floor water-based paint of the present invention include a method in which the water-based floor paint of the present invention is coated on a floor material on which an old coating film is present and dried. As the coating method, for example, various methods such as brush coating, roller coating, spray coating, dip coating, flow coater coating, roll coater coating and the like can be applied. Especially, it is suitable that it is an inorganic flooring in which an old coating film exists as a flooring in which an old coating film exists.

  Next, the present invention will be described in detail with reference examples, examples and comparative examples, but the present invention is not limited thereto. In the examples, all parts and% are based on weight unless otherwise specified.

Reference Example 1 [Preparation of polyisocyanate (A-1)]
In a four-necked flask equipped with a stirrer, thermometer, condenser, and nitrogen inlet, 32 parts of methoxypolyethylene glycol having a number average molecular weight of 560 and polyisocyanate (p-1) [Dainippon Ink Chemical Co., Ltd. Vernock DN-980S: Hexamethylene diisocyanate (hereinafter abbreviated as HDI) isocyanurate type polyisocyanate, isocyanate group content (hereinafter abbreviated as NCO group content) 21%, nonvolatile content 100%] 100 parts was charged and heated to 90 ° C. over 30 minutes, and then reacted at 90 ° C. for 6 hours to obtain a polyisocyanate modified with methoxypolyethylene glycol having a nonvolatile content of 100% and an NCO group content of 14%. Obtained. Hereinafter, this is abbreviated as polyisocyanate (A-1).

Reference Example 2 [Preparation of polyisocyanate (A-2)]
In a four-necked flask similar to Reference Example 1, 429 parts of diethylene glycol diethyl ether (hereinafter abbreviated as EDE) were charged, heated to 110 ° C. under a nitrogen stream, and then number-average molecular weight of polyoxyethylene groups. 400 parts of methoxypolyethylene glycol methacrylate (hereinafter abbreviated as MPEGMA), 200 parts of cyclohexyl methacrylate (hereinafter abbreviated as CHMA), 400 parts of methyl methacrylate (hereinafter abbreviated as MMA), t A mixed liquid consisting of 45 parts of butyl peroxy-2-ethylhexanoate (hereinafter abbreviated as TBPEH) and 5 parts of t-butyl peroxybenzoate was added dropwise over 5 hours. After completion of 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% and a weight average molecular weight of 18,000. Hereinafter, this is abbreviated as an acrylic polymer (q-1).

  Next, 200 parts of polyisocyanate (p-1) and 100 parts of acrylic polymer (q-1) were charged into a four-necked flask similar to that used for the preparation of acrylic polymer (q-1). After raising the temperature to 50 ° C. under a nitrogen stream, the mixture was stirred and mixed at the same temperature for 1 hour to obtain polyisocyanate (A-2) having a nonvolatile content of 90% and an NCO group content of 14.0% by weight. Hereinafter, this is abbreviated as polyisocyanate (A-2).

Reference Example 3 [Preparation of acrylic resin (B-1)]
In the same four-necked flask as in Reference Example 1, 16 parts of “New Coal 707SF” (anionic emulsifier manufactured by Nippon Emulsifier Co., Ltd.), “Neugen TDS-200D” [nonionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ] 6.5 parts and 220 parts of deionized water were charged and heated to 80 ° C. under a nitrogen stream, and then an aqueous solution in which 0.8 part of ammonium persulfate was dissolved in 16 parts of deionized water was added. Furthermore, 65 parts of butyl acrylate (hereinafter abbreviated as BA), 94 parts of MMA, 4 parts of acrylic acid (hereinafter abbreviated as AA) and 2-hydroxyethyl methacrylate (hereinafter abbreviated as 2-HEMA) 37 The liquid mixture consisting of parts was added dropwise over 3 hours. After the completion of the dropwise addition, the mixture was reacted for 2 hours, cooled to 25 ° C., neutralized with 1.5 parts of 28% aqueous ammonia, deionized water was added to adjust the nonvolatile content to 45%, and the solid content hydroxyl value An acrylic resin (B-1) having 80 mg KOH / g and a glass transition temperature (Tg) of 30 ° C. was obtained.

Reference Examples 4 to 7 [Preparation of acrylic resins (B-2) to (B-5)]
Acrylic resins (B-2) to (B-5) were obtained in the same manner as in Reference Example 3 except that the acrylic monomer was reacted at the ratio described in Table 1 below.

Reference Examples 8 to 10 [Preparation of acrylic resins (RB-1) to (RB-3)]
Acrylic resins (RB-1) to (RB-3) were obtained in the same manner as in Reference Example 3 except that the acrylic monomer was reacted at the ratio described in Table 2 below.

Reference Examples 11 to 13 [Preparation of acrylic resins (C-1) to (C-3)]
Acrylic resins (C-1) to (C-3) were obtained in the same manner as in Reference Example 3 except that the acrylic monomer was reacted at the ratio described in Table 3 below.

<< Footnotes in Table 3 >>
3-MPTMS: 3-methacryloxypropyltrimethoxysilane EDMA: ethylene glycol dimethacrylate

Reference Examples 14 to 16 [Preparation of acrylic resins (RC-1) to (RC-3)]
Acrylic resins (RC-1) to (RC-3) were obtained in the same manner as in Reference Example 3 except that the acrylic monomer was reacted at the ratio described in Table 4 below.

<< Footnotes in Table 4 >>
3-MPTMS: 3-methacryloxypropyltrimethoxysilane EDMA: ethylene glycol dimethacrylate LM: lauryl mercaptan

Reference Example 17 [Preparation of water-based paint base component (D-1) for floor]
85.4 parts of deionized water, 23.7 parts of “Disperbyk-190” (dispersant manufactured by BYK Chemie), 1.5 parts of a 25% aqueous solution of dimethylethanolamine, “Ti-Pure R-960” (DuPont) A mixture consisting of 270.6 parts (titanium oxide) and 5.4 parts of a 10% aqueous solution of “BYK-011” (an antifoaming agent manufactured by BYK Chemie) was dispersed with a disper for 1 hour. Next, 290 parts of acrylic resin (B-1), 290 parts of acrylic resin (C-1), “BYK-346” (leveling agent manufactured by BYK Chemie), 8.3 parts, “Primal RM-8W” ( 4.8 parts of a 10% aqueous solution of a thickener manufactured by Rohm & Haas), 1.1 parts of a 25% aqueous solution of dimethylethanolamine, and a 10% aqueous solution of “BYK-028” (an antifoaming agent manufactured by BYK Chemie) 16 And 3.3 parts of diethylene glycol dibutyl ether were added and stirred to obtain an aqueous base paint component (D-1) having a nonvolatile content of 55%.

Reference Examples 18 to 23 [Preparation of water base paint main component (D-2) to (D-7) for floor]
Instead of acrylic resin (B-1) and acrylic resin (C-1), acrylic resins (B-2) to (B-5) and acrylic resins (C-2) to (C-3) Were used in the same manner as in Reference Example 18 except that they were used in the combinations shown in Tables 5 (1) to (3) to obtain water base paint main component components (D-2) to (D-7) for flooring.

Reference Examples 24 to 28 [Preparation of water base paint main ingredient components for comparison (RD-1) to (RD-5)]
Instead of acrylic resin (B-1) and acrylic resin (C-1), acrylic resins (RB-1) to (RB-3) and acrylic resins (RC-1) to (RC-3) Were used in the same manner as in Reference Example 18 except that they were used in the combinations shown in Tables 6 (1) to (2), to obtain water base paint base components (RD-1) to (RD-5) for flooring.

Example 1
The molar ratio (NCO / OH) of the isocyanate group (NCO) in the polyisocyanate (A-2) to the hydroxyl group (OH) in the acrylic resin (B-1) and acrylic resin (C-1) is 1.2. So that 6.7 parts of polyisocyanate (A-2) and 100 parts of water-based paint main component (D-1) for flooring are mixed, and further diluted with water so that the nonvolatile content becomes 50%, A white aqueous paint (E-1) was obtained.

  Using the obtained white water-based paint (E-1), an initial coating hardness test, an adhesion test, and a water resistance test were performed as follows.

-Initial coating film hardness test: A white floor water-based paint (E-1) was applied to a slate plate with a brush so that the coating amount was 200 g / m ^2, and the temperature was 25 ° C. and the humidity was 60% RH. Hardness was measured with a Koenig hardness meter using a sample dried for one day.

・ Creation of test substrate for adhesion test evaluation: The floor paints (s-1) to (s-6), which become the old coating film, are applied to the slate plate with a brush so that the coating amount is 200 g / m ² . After drying for 24 hours under conditions of an air temperature of 25 ° C. and a humidity of 60% RH, the film is dried at 60 ° C. for 24 hours, and further dried under a condition of an air temperature of 25 ° C. and humidity of 60% RH for 2 weeks. Next, these coated slate plates were subjected to accelerated deterioration for 1000 hours using a sunshine super long life weather meter (model number WE-L-SUN-DCHD manufactured by Suga Test Instruments Co., Ltd.), and the following floor coating (s- The adhesion evaluation test base materials (S-1) to (S-6) coated with 1) to (s-6) were obtained. The accelerated deterioration condition at this time was a black panel temperature of 63 ° C. and rainfall for 18 minutes in 120 minutes.
(S-1): Solvent-based epoxy resin paint archifloor EH (manufactured by SK Kaken Co., Ltd.)
(S-2): Solvent-based urethane resin paint arc floor UT (manufactured by SK Kaken Co., Ltd.)
(S-3): Solvent-based acrylic resin paint archifloor AS (manufactured by SK Kaken Co., Ltd.)
(S-4): Water-based epoxy resin paint water-based atom Epoclean (Atomics)
(S-5): Water-based urethane resin paint Aqua Clean U (manufactured by Atomics))
(S-6): Water-based acrylic resin coating amount floor top # 1000 (manufactured by Atomics)

-Adhesion test: The coating amount of the aqueous paint for white floor (E-1) is applied with a brush on the slate plate and the deteriorated coating film of the adhesion evaluation test base materials (S-1) to (S-6). An adhesion test was performed using a sample coated at 200 g / m ² and dried for 7 days under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. In the adhesion test, 100 squares were formed by cutting with a cutter knife at intervals of 1 mm in length and breadth, and a film peeling test was performed with a cellophane adhesive tape. Evaluation evaluated the adhesion between the coating film and the slate plate, the coating film and the deteriorated coating film of the test substrate for adhesion evaluation (S-1) to (S-6), and evaluated by the remaining number. Those with 95 or more remaining can be evaluated as having good adhesion.

Water resistance test: White floor water-based paint (E-1) is applied onto the deteriorated coating film of the above-mentioned adhesion evaluation test base materials (S-1) and (S-6) with a brush and applied in an amount of 200 g / m. ^No blistering occurred when the sample was coated for 2 days and dried for 7 days under conditions of 25 ° C and 60% RH, and dipped in water at 25 ° C for 1 day. Was evaluated according to the following evaluation criteria. A product having little blister (less than 5%) can be evaluated as having good water resistance.
Evaluation criteria ◎: No blister ○: Slightly blistered. Blister area less than 2%.
○-△: Slightly blistered. Blister area 2% to less than 5%.
Δ: Blister on the entire surface. Blister area 5% to less than 15%.
Δ- ×: Blister is present on the entire surface. Blister area 15% or more and less than 30%.
X: Blister on the entire surface. Blister area more than 30%.

Examples 2-9
Instead of polyisocyanate (A-2) and water-based paint main component (D-1) for floor, polyisocyanates (A-1) to (A-2) and water-based paint main component (D-1) to (D-1) to ( White floor water-based paints (E-2) to (E-9) were prepared in the same manner as in Example 1 except that D-7) was used in the combinations shown in Table 5 (1) to (2). The same evaluation as in Example 1 was performed. The test results are shown in Tables 5 (1) to (2).

Comparative Examples 1-5
Instead of polyisocyanate (A-2) and water-based paint main component (D-1) for floor, polyisocyanates (A-1) to (A-2) and water-based paint main component for floor (RD-1) to ( White floor aqueous paints (RE-1) to (RE-5) were prepared in the same manner as in Example 1 except that RD-5) was used in the combinations shown in Tables 6 (1) to (2). The same evaluation as in Example 1 was performed. The test results are shown in Tables 6 (1) to (2).

Claims (9)

A polyisocyanate (A), an acrylic resin (B) having a hydroxyl value of 40 to 150 mgKOH / g, and an acrylic resin (C) having a weight average molecular weight of 350,000 or more and a hydroxyl value of 0 to 15 mgKOH / g are contained in an aqueous medium. Water-based paint for floors, characterized by being dispersed in the floor. The water base for floors according to claim 1, wherein the glass transition temperature (Tg) of the acrylic resin (B) is 15 to 70 ° C, and the glass transition temperature (Tg) of the acrylic resin (C) is 30 to 75 ° C. paint. The water-based floor paint according to claim 2, wherein the weight ratio [(B) / (C)] of the acrylic resin (B) and the acrylic resin (C) is in the range of 0.3 to 3. The acrylic resin (B) has a hydroxyl value of 50 to 120 mgKOH / g, the acrylic resin (C) has a hydroxyl value of 0 to 12 mgKOH / g, and the weight ratio of the acrylic resin (B) to the acrylic resin (C) [ The floor paint according to claim 1, wherein (B) / (C)] is in the range of 0.4 to 2.2. The water base for floors according to claim 4 whose glass transition temperature (Tg) of acrylic resin (B) is 25-60 ° C, and whose glass transition temperature (Tg) of acrylic resin (C) is 40-65 ° C. paint. The molar ratio (NCO / OH) of the total (OH) of the isocyanate group (NCO) in the polyisocyanate (A), the hydroxyl group in the acrylic resin (B) and the hydroxyl group of the acrylic resin (C) is 0.5. It is -2.5. The water-based paint for floors of any one of Claims 1-5. The molar ratio (NCO / OH) of the total (OH) of the isocyanate group (NCO) in the polyisocyanate (A) and the hydroxyl group in the acrylic resin (B) and the hydroxyl group in the acrylic resin (C) is 0.7. It is -1.5. The water-based paint for floors of any one of Claims 1-5. A floor coating method comprising: coating the floor water-based paint according to any one of claims 1 to 7 on a floor material on which an old coating film exists and drying the floor paint. The floor coating method according to claim 8, wherein the floor material is an inorganic floor material having an old coating film.