JP2007126623A - Water-based paint for floor and floor coating method - Google Patents

Abstract

To provide a water-based paint for floors excellent in recoatability and initial hardness, and excellent in water resistance, and a floor coating method using the water-based paint for floors.
SOLUTION: Polyisocyanate (A) and at least 60 mol%, preferably 60 to 80 mol% have primary hydroxyl groups and secondary hydroxyl groups in a molar ratio of secondary hydroxyl groups, and the hydroxyl value is 50 to 120 mgKOH / g, preferably 60 to 100 mg KOH / g, and an aqueous acrylic resin (B) having a hydroxyl value based on primary hydroxyl groups of 20 to 40 mg KOH / g dispersed in an aqueous medium, and this A floor coating method in which a water-based paint for flooring is coated on a flooring material on which a primer may be coated and dried, and then the water-based paint for flooring is further coated thereon and dried.
[Selection figure] None.

Description

  The present invention relates to a water-based floor paint excellent in recoatability and a coating method thereof.

  Conventionally, many floor coatings using a polyisocyanate composition and an organic solvent-based curable composition comprising an organic solvent-based resin having an active hydrogen-containing group have been used. In recent years, there has been a strong demand in the paint field from the viewpoint of environmental problems to reduce the content of volatile organic solvents contained in paints. This trend is the same for floor coatings. 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. Attempts have been made to make the curable composition aqueous. For example, an aqueous curable composition comprising a polyisocyanate and an aqueous resin having a hydroxyl value of 10 to 200 and a primary hydroxyl group / secondary hydroxyl group (molar ratio) of 5/95 to 55/45, or curing thereof. It has been reported that a water-based paint comprising a product can provide a water-based paint excellent in hardness, appearance, water resistance and solvent resistance (for example, Patent Document 1).

  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 recoating ability in the coating process is an important workability. Further, 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 of coating or the next day. However, the aqueous coating composition using the aqueous curable composition described in Patent Document 1 does not have sufficient recoating property and initial hardness, and is relatively excellent in water resistance, but is not sufficient. The development of water-based paint for floors that is superior in water resistance and water resistance is expected.

  In addition, the recoatability in the floor paint is the suitability for recoating. When applying after a certain coating interval, repainting an insufficiently applied part, securing the film thickness, etc. It can be expressed as the adhesion of the coated film. This recoatability is an important performance in floor coatings. In general, the recoatability decreases with the passage of time after coating after the solvent and water volatilize. This is because the cross-linking density on the surface of the coating film is increased by the curing reaction, and the coated film is difficult to adhere.

  Moreover, initial hardness shows the coating-film hardness 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

  An object of the present invention is to provide a water-based paint for floors excellent in recoatability and initial hardness and excellent in water resistance, and a floor coating method using the water-based paint for floors.

  As a result of intensive studies in view of such a current situation, the present inventors, as a resin having an active hydrogen-containing group, a hydroxyl group-containing acrylic resin in a specific range not specifically shown in Patent Document 1, That is, the hydroxyl value is 50 to 120 mgKOH / g, the acid value based on the primary hydroxyl group is 20 to 40 mgKOH / g, and the molar ratio of the secondary hydroxyl group in the primary and secondary hydroxyl groups is 60 mol% or more. The water-based paint for floors formed by using acrylic resins (B) each limited and dispersed in an aqueous medium together with the polyisocyanate (A) is excellent in recoatability, initial hardness and water resistance. As a floor coating method using a water-based paint, the floor-based water-based paint is coated on a floor material which may be coated with a primer, dried, and then further on the floor-based water-based paint. Coating The method of drying found that preferably, the present invention has been completed.

  That is, the present invention has a primary hydroxyl group and a secondary hydroxyl group in a molar ratio of polyisocyanate (A) and at least 60 mol% of a secondary hydroxyl group, a hydroxyl value of 50 to 120 mgKOH / g, and a primary class. The present invention provides a water-based paint for floors characterized in that an acrylic resin (B) having a hydroxyl value based on hydroxyl groups of 20 to 40 mgKOH / g is dispersed in an aqueous medium.

  In addition, the present invention, the water-based paint for flooring is applied on a flooring material on which a primer may be applied, and after drying, the water-based paint for flooring is further applied thereon, The present invention provides a floor coating method characterized by drying.

  ADVANTAGE OF THE INVENTION According to this invention, the water-based coating material for floors excellent in the recoat property, initial stage hardness, and water resistance which was considered until now can be obtained. In addition, according to the floor coating method of the present invention, it is easy to repeat the coating operation, the coating can be performed more efficiently in a shorter time than before, and a coating film excellent in hardness, appearance, water resistance, solvent resistance, etc. is formed. Can be obtained easily and efficiently.

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;

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

  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. A tri- or higher functional polyisocyanate such as a polyisocyanate obtained by reacting an isocyanate or diisocyanate with a trihydric or higher polyhydric alcohol is preferred.

  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, the addition of a component capable of dispersing polyisocyanate (A) such as various emulsifiers in an aqueous medium and the ability to disperse polyisocyanate (A) in water as an acrylic resin (B) described later And the polyisocyanate (A) may be dispersed in an aqueous medium by mixing with an aqueous dispersion of the acrylic resin (B). Furthermore, you may disperse | distribute polyisocyanate (A) in an aqueous medium with the combination of the said method.

  As the nonionic group 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 anion described later. A polyoxyalkylene group such as a polyoxyalkylene group which is a functional group. More preferably, it is a polyoxyalkylene group whose end is blocked with an alkoxy group, and representative examples thereof include polyoxyalkylene groups such as polyoxyethylene groups, polyoxypropylene groups, polyoxybutylene groups, poly ( (Oxyethylene-oxypropylene) group or the like in which the above-described oxyalkylene moiety is randomly copolymerized, different polyoxyalkylene groups such as polyoxyethylene-polyoxypropylene group are combined in a block form, or the like Can be 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-dispersibility, but an acid group neutralized with a basic compound is preferable. Examples of neutralized acid groups include sulfonate groups, sulfate ester bases, phosphate groups, phosphate ester bases, phosphonate groups, phosphonate ester bases, phosphinate groups, sulfines. An acid group, a carboxylate group, and the like.

  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, Preference is given to sulfonate groups and sulfate ester bases.

  Typical examples of the basic compound used in converting to an anionic group as described above by neutralizing an acid group include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, 2-amino Organic amines such as ethanol and 2-dimethylaminoethanol; inorganic basic compounds such as ammonia, lithium hydroxide, sodium hydroxide and potassium hydroxide; tetramethylammonium hydroxide, tetra-n-butylammonium hydroxide or trimethylbenzyl And quaternary ammonium hydroxides such as ammonium hydroxide. 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) just before mixing with acrylic resin (B) mentioned later.

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

  The acrylic resin (B) used in the present invention is required to have a hydroxyl value of 50 to 120 mgKOH / g. If the hydroxyl value is lower than 20, sufficient water resistance cannot be obtained, and if it is higher than 210, the hydrophilic hydroxyl group lowers water resistance and at the same time lowers the pot life of the floor water-based paint, which is not preferable. The range of the hydroxyl value is more preferably from 60 to 100 mgKOH / g, and most preferably from 65 to 90 mgKOH / g, since an aqueous floor coating having excellent initial hardness and water resistance of the coating film can be obtained.

  The acrylic resin (B) has a primary hydroxyl group and a secondary hydroxyl group, but at least 60 mol% needs to be a secondary hydroxyl group. When the secondary hydroxyl group is less than 50 mol%, the recoatability is lowered, which is not preferable. It is preferable that at least 65 mol% is a secondary hydroxyl group because an aqueous floor coating excellent in recoatability can be obtained. Moreover, it is preferable that 60-80 mol% is a secondary hydroxyl group, and 65-75 mol% is a secondary hydroxyl group from the water-based coating material for floors with which the balance of recoat property and initial stage coating-film hardness is favorable. More preferably.

  The acrylic resin (B) has a primary hydroxyl group and a secondary hydroxyl group, but the hydroxyl value based on the primary hydroxyl group is required to be 20 to 40 mgKOH / g. When the hydroxyl value based on the primary hydroxyl group is lower than 10 mgKOH / g, the initial coating film hardness is low and the workability is poor. When it is higher than 40 mgKOH / g, the recoatability is lowered. It is preferable that the hydroxyl value based on the primary hydroxyl group is 25 to 35 mgKOH / g because an aqueous floor coating having excellent initial coating film hardness and recoatability can be obtained.

  The acrylic resin (B) has a glass transition temperature (Tg) measured by a differential scanning calorimeter of 15 to 15 because an aqueous floor coating excellent in initial coating film hardness, recoatability and film-forming property can be obtained. It is preferable that it is 60 degreeC, and it is more preferable that it is 25-40 degreeC especially.

  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. (2) Polyisocyanate (A) or polyisocyanate (A) added with an emulsifier is added to water-dispersed acrylic resin (B). Method of directly adding, mixing and dispersing [However, when an isocyanate having no self-water dispersibility is used as the polyisocyanate (A), the water-dispersed acrylic resin (B) has the ability to disperse the polyisocyanate in water. It is necessary to use something. ] Etc. are mentioned.

  The acrylic resin (B) used in the present invention can be produced, for example, by copolymerizing an acrylic monomer having a hydroxyl group and other acrylic monomers. Further, if necessary, vinyl monomers other than acrylic monomers can be used.

  Among the acrylic monomers having a hydroxyl group, examples of the acrylic monomer capable of introducing a primary hydroxyl group into the acrylic polymer (B) include 2-hydroxyethyl (meth) acrylate, 3- Examples thereof include hydroxypropyl (meth) acrylate and 4-hydroxybutyl acrylate. Examples of the acrylic monomer capable of introducing a secondary hydroxyl group into the acrylic polymer (B) include 2-hydroxypropyl (meth) acrylate, 2-hydroxy-n-butyl (methacrylate), 3-hydroxy-n-butyl (meth) acrylate etc. are mentioned, Preferably 2-hydroxypropyl (meth) acrylate is mentioned.

  Examples of the other acrylic monomers include (meth) acrylic acid and alkali metal salts thereof, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, Acrylic monomers such as acrylic amide, N, N-dimethyl (meth) acrylic amide, (meth) acrylonitrile, 3- (meth) acryloylpropyltrimethoxysilane, 2-dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, etc. A monomer is mentioned.

  The acrylic resin (B) used in the present invention is in a state of being dispersed in an aqueous medium, and various dispersion forms are exemplified. Broadly speaking, there are (1) an acrylic resin (B1) dispersed in an aqueous medium with an emulsifier, and (2) an acrylic resin (B2) having a hydrophilic group dispersed in an aqueous medium.

  Examples of the acrylic resin (B1) dispersed in an aqueous medium with the above-mentioned emulsifier (1) include an acrylic resin (B1), an emulsifier and water that are stirred to disperse the acrylic resin (B1) in water. Examples thereof include those obtained by emulsion polymerization of a system monomer in an aqueous medium in the presence of an emulsifier.

  Examples of the emulsifier that can be used when the acrylic resin (B1) is dispersed in water by stirring the acrylic resin (B1), the emulsifier, and water include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, poly Nonionic emulsifiers such as oxyethylene polyoxypropylene copolymers, alkyl sulfate esters, alkylbenzene sulfonates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates, etc. Anionic emulsifiers, quaternary And cationic emulsifiers such as ammonium salts. 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.

  Moreover, as an emulsifier which can be used when emulsion polymerization is performed, any of the nonionic emulsifiers, anionic emulsifiers and cationic emulsifiers listed as emulsifiers which can be used when the acrylic resin (B1) is dispersed in water can be used. . The emulsifier is preferably used in the range of 10 parts by weight or less with respect to 100 parts by weight of the total weight of the monomer, and further, from 2 to 5% by weight is obtained because a water-based paint for flooring excellent in water resistance is obtained. 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 initiators used is usually 0.01-5 parts by weight, preferably 0.05-2 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. Emulsion of the target acrylic resin (B1) by performing 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 Can be obtained.

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

  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 acidic compounds that can be used when 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, 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 Among 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 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.

  The acrylic resin (B2) having a target hydrophilic group is prepared by applying the solution radical polymerization method using monomers, polymerization initiators and organic solvents as described above. be able to.

  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 (phase inversion emulsification) 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 or 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. 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 in the case of using an organic solvent is at least 1 weight% or more.

  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 organic or inorganic pigments. In the acrylic resin (B) used in the present invention, an additive such as a filler, a leveling agent, a thickener, an antifoaming agent, an organic solvent, an ultraviolet absorber, an antioxidant or a pigment is used as necessary. Various commonly known additives such as a 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 pigment is 0.1 to 300 with respect to 100 parts by weight in total of the solid content of the polyisocyanate (A) and the solid content of the acrylic resin (B). What is necessary is just to mix | blend a pigment in the ratio which becomes a weight part, Preferably 0.2-200 weight part.

  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 0 degree of ultraviolet absorbers and / or antioxidant with respect to a total of 100 weight part of solid content of polyisocyanate (A) and solid content of acrylic resin (B). The ratio may be set to 2 to 10 parts by weight, preferably 0.5 to 5 parts by weight.

  The water-based paint for floors of the present invention is obtained by dispersing the polyisocyanate (A) and the acrylic resin (B) in an aqueous medium, but the polyisocyanate (A) and the acrylic resin (B). As a method for mixing, for example, a method in which polyisocyanate (A) or polyisocyanate (A) dispersed in an aqueous medium is added to an acrylic resin (B) dispersed in an aqueous medium, followed by stirring. Is mentioned. As a stirring method, for example, there is a method of using various stirrers, and simple stirring using a stirrer or the like may be used if the amount is small, but using a variety of stirrers can produce a large amount of aqueous curable in a short time. It is preferable because the composition can be prepared. Moreover, when polyisocyanate (A) does not have self-dispersibility, it is preferable to use well-known and usual various stirrers which have strong shearing force, such as a jet mill, for example.

  The mixing ratio of the polyisocyanate (A) and the acrylic resin (B) at this time is that the water-based paint for flooring excellent in recoatability, initial hardness and water resistance of the present invention is obtained. The molar ratio (NCO / OH) of the isocyanate group to the hydroxyl group in the acrylic resin (B) is preferably 0.5 to 2.5, more preferably 0.7 to 2.0, and 0 More preferably, it is 9-1.5.

  The water-based paint for floors of the present invention can be applied directly on a flooring material, or can be applied on a flooring material coated with various primers. Furthermore, the water-based paint for flooring of the present invention is coated on the flooring material on which the primer may be applied and dried, and then the water-based paint for flooring of the present invention is further applied thereon and dried. be able to. The coating method for recoating the water-based paint for floors of the present invention is a particularly preferred coating method because it makes use of the characteristics of the water-based paint for floors of the present invention that is excellent in recoatability and initial hardness.

  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 an inorganic base material, for example, a cured product produced from a calcium compound such as calcium silicate, calcium aluminate, calcium sulfate, calcium oxide; a 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-based substrate 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 the plastic substrate include molded products of thermoplastic resins such as polystyrene, polycarbonate, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride, polypropylene, polybutylene terephthalate, polyethylene terephthalate; unsaturated polyester Examples thereof include molded products of thermosetting resins such as resins, phenol resins, cross-linked polyurethanes, cross-linked acrylic resins, and cross-linked saturated polyester resins.

  Moreover, even if it is various base materials as mentioned above, and the coating has been given and the degradation of the coating portion has progressed, it can be used as the base material in the present invention. I can do it.

  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.

  As a method for applying the water-based paint for flooring of the present invention, known and commonly used methods such as brush coating, roller coating, spray coating, dip coating, flow coater coating and roll coater coating can be applied.

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

Reference Example 1 [Preparation of polyisocyanate (A-1)]
In a four-necked flask equipped with a stirrer, a thermometer, a cooling pipe, and a nitrogen introduction pipe, 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) -based isocyanurate type polyisocyanate, isocyanate group content (hereinafter abbreviated as NCO group content) 21%, nonvolatile content 100%] 100 The polyisocyanate modified with methoxypolyethylene glycol having a non-volatile content of 100% and an NCO group content of 14% by weight was obtained by reacting at 90 ° C. for 6 hours. It was. 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 reactor similar to that used for the preparation of acrylic polymer (q-1), and a nitrogen stream was supplied. The temperature was raised to 50 ° C., and 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, "Hytenol N-08" (anionic emulsifier manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), 5 parts, "Emulgen 931" (nonionic emulsifier manufactured by Kao Corporation) 5 And 240 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. Further, 54 parts of butyl acrylate (hereinafter abbreviated as BA), 102 parts of MMA, 4 parts of acrylic acid (hereinafter abbreviated as AA), 2-hydroxyethyl methacrylate (hereinafter abbreviated as 2-HEMA) 11 And a mixed liquid consisting of 29 parts of 2-hydroxypropyl methacrylate (hereinafter abbreviated as 2-HPMA) was dropped over 3 hours. After completion of the dropwise addition, the reaction was allowed to proceed for 2 hours, followed by cooling to 25 ° C. and neutralization with 1.5 parts of 28% aqueous ammonia, 45% non-volatile content, solid content hydroxyl value of 80 mg KOH / g, Acrylic resin (B-1) having a glass transition temperature (Tg) of 35 ° C. measured by a differential scanning calorimeter with a molar ratio of secondary hydroxyl groups to the total of primary and secondary hydroxyl groups of 70 mol%, with a base value of 24 mgKOH / g. )

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 13 [Preparation of acrylic resins (RB-1) to (RB-6)]
As in Reference Example 1, acrylic monomers were reacted at the ratios listed in Table 2 to obtain acrylic resins (RB-1) to (RB-6).

Reference Example 14 [Preparation of water-based paint base component (C-1) for floor]
85.4 parts of deionized water, 23.7 parts of “Disperbyk-190” (an antifoaming agent manufactured by BYK Chemie), 1.5 parts of a 25% aqueous solution of dimethylethanolamine, “Ti-Pure R-960” (DuPont) A mixture of 270.6 parts (titanium oxide) and 5.4 parts of a 10% aqueous solution of “BYK-011” was dispersed with a disper for 1 hour. Next, 579.9 parts of acrylic resin (B-1), “BYK-346” (leveling agent manufactured by BYK Chemie) 8.3 parts, “Primal RM-8W” (thickener manufactured by Rohm & Haas) 4.8 parts of a 10% aqueous solution, 1.1 parts of a 25% aqueous solution of dimethylethanolamine and 19.3 parts of a 10% aqueous solution of “BYK-028” (an antifoaming agent manufactured by BYK Chemie) were added and stirred. 55% of a water base paint main ingredient component (C-1) for floor was obtained.

Reference Examples 15 to 18 [Preparation of water base paint main component (C-2) to (C-5) for floor]
Aqueous base paint component for flooring (C-2) in the same manner as in Reference Example 14 except that acrylic resins (B-2) to (B-5) were used instead of acrylic resin (B-1). To (C-5).

Reference Examples 19 to 24 [Preparation of water base paint main component (RC-1) to (RC-6) for floor]
Water base paint main component (RC-1) for flooring in the same manner as in Reference Example 14 except that acrylic resins (RB-1) to (RB-6) were used instead of acrylic resin (B-1). To (RC-6) was obtained.

Example 1
Polyisocyanate (ACO) such that the molar ratio (NCO / OH) of isocyanate group (NCO) in polyisocyanate (A-2) to hydroxyl group (OH) in acrylic resin (B-1) is 1.2. -2) 13.4 parts and 100 parts of a water base paint main component (C-1) for floors are mixed and further diluted with water so that the non-volatile content is 50%. ) Was prepared.

  Using the resulting white floor water-based paint (D-1), a coating film hardness test, an adhesion test, and a water resistance test were conducted as follows.

Coating film hardness test: White floor water-based paint (D-1) is applied to a slate plate with a brush so that the coating amount is 200 g / m ² and dried for one day under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. The white floor water-based paint (D-1) was applied again to the product and dried for 1 day under conditions of an air temperature of 25 ° C. and a humidity of 60% RH, and the hardness was measured using a Koenig hardness meter.

Adhesion test: White floor water-based paint (D-1) is applied to a slate plate with a brush so that the coating amount is 200 g / m ² and dried for 8 hours under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. The white floor water-based paint (D-1) was applied again to each of the dried product, the dried product for 1 day, and the dried product for 3 days, and dried for 3 days under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. The adhesion test was performed using the prepared samples as samples. The adhesion test was a recoat property evaluation test, in which 100 squares were made by cutting with a cutter knife at intervals of 1 mm in length and width, and a peeling test of the coating film was performed with a cellophane adhesive tape. Evaluation evaluated the adhesion between the 1st coating film and the 2nd coating film, and evaluated by the remaining number. Those with 95 or more remaining can be evaluated as having good recoatability.

Water resistance test: White floor water-based paint (D-1) is applied to a slate plate with a brush so that the coating amount is 200 g / m ² and dried for one day under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. A white floor water-based paint (D-1) was applied again to the sample and dried for 3 days under conditions of an air temperature of 25 ° C. and a humidity of 60% RH, and immersed in water at a water temperature of 25 ° C. for 1 day. The occurrence of blisters when pulled up 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 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 2-7
Implemented except that polyisocyanate (A-2) and water-based paint main component (C-1) for floor use were used instead of polyisocyanate and water-based paint main component for floor shown in Table 3 (1) to (2). In the same manner as in Example 1, water base paints (D-2) to (D-7) for white floor were prepared, and the same evaluation was performed. The test results are shown in Tables (1) to (2).

Comparative Examples 1-8
Implemented except that the polyisocyanate (A-2) and the aqueous base paint component for flooring (C-1) were replaced with the polyisocyanate and the aqueous base paint component for floor shown in Tables 4 (1) to (2). In the same manner as in Example 1, white floor water-based paints (RD-1) to (RD-8) were prepared and evaluated in the same manner. The test results are shown in Tables 4 (1) to (2).

Claims (6)

Polyisocyanate (A) has a primary hydroxyl group and a secondary hydroxyl group at a molar ratio of at least 60 mol% of a secondary hydroxyl group, a hydroxyl value of 50 to 120 mgKOH / g, and a hydroxyl value based on the primary hydroxyl group A water-based paint for floors, characterized in that an acrylic resin (B) of 20 to 40 mg KOH / g is dispersed in an aqueous medium. Acrylic resin (B) has a primary hydroxyl group and a secondary hydroxyl group in a molar ratio of 60 to 80 mol% of a secondary hydroxyl group, a hydroxyl value of 60 to 100 mgKOH / g, and a hydroxyl group based on the primary hydroxyl group The water-based paint for flooring according to claim 1, which is an acrylic resin having a value of 20 to 40 mgKOH / g. The water-based paint for flooring according to claim 2, wherein the acrylic resin (B) is an acrylic resin having a glass transition temperature (Tg) measured by a differential scanning calorimeter of 15 to 60 ° C. The molar ratio (NCO / OH) of the isocyanate group (NCO) in the polyisocyanate (A) to the hydroxyl group (OH) in the acrylic resin (B) is 0.5 to 2.5. The water-based paint for floors described in 1. The water-based paint for floors according to any one of claims 1 to 4 is coated on a flooring material on which a primer may be coated, dried, and then further water-based on the floor. A floor coating method characterized in that a paint is applied and dried. The floor coating method according to claim 1, wherein the floor material is an inorganic floor material.