JP2008063373A - Water-based coating material for floor and floor-coating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based coating material having excellent attachability to an old coated film and recoating properties, and providing a coated film having excellent initial hardness and water resistance; and to provide a floor-coating method using the coating material. <P>SOLUTION: The water-based coating material for the floor is obtained by dispersing (A) a polyisocyanate, (B) an acrylic resin containing a primary hydroxy group and a secondary hydroxy group in a molar ratio regulated so that the secondary hydroxy group may be at least 60 mol%, and having 50-120 mg KOH/g hydroxy value and 20-40 mg KOH/g hydroxy value originated from the primary hydroxy group, and (C) an acrylic resin having ≥350,000 weight average molecular weight and 0-15 mg KOH/g hydroxy value. The floor-coating method includes coating the water-based coating material for the floor on a floor material which may have an old coated film or primer, drying the coated floor, further coating the water-based coating material for the floor thereon, and drying the coated floor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a water-based floor paint excellent in old paint film adhesion and recoatability, 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, an aqueous curable composition comprising polyisocyanate and an aqueous resin having a hydroxyl value of 10 to 200 mg KOH / g and a primary hydroxyl group / secondary hydroxyl group (molar ratio) of 5/95 to 55/45, or According to a water-based paint comprising the cured product, it has been reported that a water-based paint excellent in hardness, appearance, water resistance, solvent resistance, and adhesion to some old paint films can be provided (for example, patents) Reference 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. Furthermore, the recoating ability, so-called recoatability, in the coating process is also an important workability. 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, since recoatability and water resistance are not sufficient, development of a water-based paint for floors having better recoatability and water resistance is expected.

  In addition, in the aqueous paint using the aqueous resin composition described in Patent Document 2, particularly the aqueous paint composition described in Example 2, the hydroxyl group having a solid content hydroxyl value of 20 mgKOH / g or more is relatively high. Since the acrylic resin emulsion (B-2) is used, the initial hardness after coating is excellent, but adhesion to various old coating films and water resistance 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.

  In addition, the recoating property in floor coating is the suitability for overcoating. When applying after a certain coating interval, repainting an insufficiently painted 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.

  The initial hardness indicates the performance of the coated film after coating, and may be in a state where it 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

  An object of the present invention is to provide a floor-use water-based paint excellent in old paint film adhesion and recoatability and excellent in initial hardness and water resistance of the paint film, and a floor coating method using this paint. .

  As a result of diligent research in consideration of such a current situation, the present inventors have specifically shown in Patent Document 1 as a resin having an active hydrogen-containing group in the water-based paint described in Patent Document 1. A specific range of hydroxyl group-containing acrylic resins, that is, a hydroxyl value of 50 to 120 mgKOH / g, an acid group value based on primary hydroxyl groups of 20 to 40 mgKOH / g, and 2 occupied by primary and secondary hydroxyl groups An acrylic resin having a molar ratio of primary hydroxyl groups of 60 mol% or more is an acrylic resin having a molecular weight of a certain value and having a hydroxyl value of a certain value or less, that is, a weight average molecular weight of 350,000 or more and a hydroxyl value of 0 The water-based paint for floors used in combination with -15 mg KOH / g acrylic resin exhibits excellent old film adhesion and recoatability, and is excellent in initial hardness and water resistance. As a coating method using a water-based paint for flooring, a method of painting and drying on a flooring material on which an old paint film exists or a flooring on which a primer may be coated is applied, and the coating is repeated on the flooring material. The inventors have found that the method is preferable and have completed the present invention.

  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. An acrylic resin (B) having a hydroxyl value based on a hydroxyl group of 20 to 40 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 the aqueous medium. The present invention provides a water-based floor paint characterized by being dispersed.

  Further, the present invention provides a floor coating method characterized by coating a floor water-based paint on a floor material on which an old paint film exists, and drying the floor water-based paint. A floor coating method characterized in that after coating and drying on an existing flooring material, the floor water-based paint is further coated thereon and dried, and a floor water-based paint, A floor coating method is provided, wherein the primer is coated on a floor material which may be coated and dried, and then the water-based paint for flooring is further coated thereon and dried. To do.

  The water-based paint for floors of the present invention is excellent in old film adhesion and recoatability, which has been considered difficult so far, and is excellent in initial hardness and water resistance. In addition, according to the floor coating method of the present invention, since the water-based paint for floors excellent in old paint adhesion, recoatability, initial strength and water resistance is used, the paint film excellent in old paint adhesion and water resistance is obtained. The formed floor can be easily formed efficiently with good 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 is required to have a hydroxyl value of 50 to 120 mgKOH / g. When the hydroxyl value is lower than 50, sufficient water resistance cannot be obtained, and when it is higher than 120, the hydroxyl group which is a hydrophilic group decreases water resistance. The range of the hydroxyl value is preferably 60 to 100 mgKOH / g, and more preferably 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 60 mol%, the old film adhesion and recoatability are lowered, which is not preferable. It is preferable that at least 65 mol% is a secondary hydroxyl group because a floor-based water-based paint that is superior in old film adhesion and recoatability can be obtained. Moreover, it is preferable that 60-80 mol% is a secondary hydroxyl group, since the water-based paint for floors with a good balance of old coating adhesion, recoatability and initial coating hardness is obtained, and 65-75 mol % Is more preferably a secondary hydroxyl group.

  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 20 mgKOH / g, the initial coating film hardness is low and the workability is inferior, and when it is higher than 40 mgKOH / g, the old coating film adhesion and recoatability are lowered. It is preferable that the hydroxyl value based on the primary hydroxyl group is 25 to 35 mgKOH / g because an aqueous coating for flooring excellent in old paint adhesion, initial coat hardness and recoatability can be obtained.

  The glass transition temperature (Tgb) of the acryl-based resin (B) is not particularly limited, but an aqueous floor paint excellent in recoatability, old film adhesion, and initial hardness can be obtained. It is preferable that it is 25-60 degreeC.

In the present invention, the glass transition temperature (Tg) of the acrylic resin is determined by the following method.
The glass transition temperature (Tg) in the present invention is a numerical value obtained by converting the glass transition temperature (TgK) represented by the absolute temperature (K) calculated by the following Fox equation into the Celsius temperature (° C.).
100 / TgK = W1 / Tg1 + W2 / Tg2 + W3 / Tg3 + W4 / Tg4...
-In formula, W1, W2, W3, W4 ... shows the mass fraction (mass%) of various components.
In the formula, Tg1, Tg2, Tg3, Tg4,... Indicate the glass transition temperature of the homopolymer of each monomer component in terms of absolute temperature (K). Here, the glass transition temperatures (Tg1, Tg2, Tg3, Tg4...) Of the homopolymers of the above monomer components expressed by the absolute temperature (K) are Polymer Handbook (Second Edition, J, Brandrup E, H, Immergut. Ed) were used.

  The molecular weight of the acrylic resin (B) is not particularly limited, but a number average molecular weight of 5,000 to 500 is obtained because an aqueous paint for flooring excellent in old film adhesion, recoatability, and initial hardness can be obtained. The weight average molecular weight is preferably 10,000 to 1,000,000, the number average molecular weight is 10,000 to 500,000, and the weight average molecular weight is 30,000 to 1,000,000. More preferably, the number average molecular weight is 20,000 to 500,000, and the weight average molecular weight is most preferably 50,000 to 1,000,000.

  In the present invention, the number average molecular weight and the weight average molecular weight of the acrylic resin are the number average molecular weight and the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography, and the weight is determined using a gel permeation chromatography apparatus. The molecular weight is assigned to the measured sample by a calibration curve created using a monodisperse standard polystyrene having a ratio (dispersion) of the average molecular weight (Mw) to the number average molecular weight (Mn) of 1, which is actually 1.10 or less. Is. The weight average molecular weight (Mw) is calculated by the following calculation 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, a measuring apparatus and measurement conditions are shown below.
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:
When the weight molecular weight is 100,000 to 1,000,000: A (column 6) with four (columns 5) connected is used.
When the weight 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 5 or 6 kinds of standard polystyrenes having different molecular weights are weighed and dissolved in 100 ml of tetrahydrofuran (hereinafter abbreviated as THF). Dissolution was carried out at 20 ° C. and used after standing for 24 hours.
Sample preparation: 80 mg of sample (solid content) is weighed and dissolved in 20 ml of THF.

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

  However, when the molecular weight is measured by gel permeation chromatography, if there is an insoluble component in THF as a developing solvent, the number average molecular weight of the insoluble portion is at least 100,000 and the weight average molecular weight is at least 500,000. However, if there are too many THF-insoluble components, the coating film cannot be formed sufficiently and is not suitable for use as a water-based paint. Accordingly, for use as a water-based paint for floors, the THF-insoluble component of the acrylic resin (B) at 25 ° C. is preferably less than 60% by weight, more preferably less than 20% by weight, and more preferably 5% by weight. Most preferably, it is less than.

  The acrylic resin (B) is obtained by, for example, copolymerizing an acrylic monomer having a primary hydroxyl group, an acrylic monomer having a secondary hydroxyl group, and other acrylic monomers. Can be manufactured. 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 primary hydroxyl group used for introducing a primary hydroxyl group into the acrylic resin (B) include 2-hydroxyethyl (meth) acrylate and 3-hydroxypropyl (meth). Examples include acrylate and 4-hydroxybutyl (meth) acrylate. Examples of the acrylic monomer having a secondary hydroxyl group used to introduce a secondary hydroxyl group into the acrylic resin (B) include 2-hydroxypropyl (meth) acrylate and 2-hydroxy-n. -Butyl (meth) acrylate, 3-hydroxy-n-butyl (meth) acrylate, etc. are mentioned, and 2-hydroxyethyl (meth) acrylate is particularly preferred.

  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, and the like. (Meth) acrylic acid esters, acrylic amide, N, N-dimethyl (meth) acrylic amide, (meth) acrylonitrile, 3- (meth) acryloylpropyltrimethoxysilane, 2-dimethylaminoethyl (meth) acrylate And glycidyl (meth) acrylate.

  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.

  Among 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 potassium persulfate, sodium persulfate, and ammonium persulfate. Persulfates, 2,2'-azobisisobutyronitrile, azo compounds such as dimethyl-2,2'-azobisisobutyrate, benzoyl peroxide, tert-butylperoxy-2-ethylhexanoate And an organic peroxide such as cumene hydroperoxide, and a redox initiator based on a combination of a reducing agent such as iron oxide. 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 order to obtain the target acrylic resin (B1) by the radical emulsion polymerization, for example, the acrylic monomer in 100 to 500 parts by weight of water with respect to 100 parts by weight of the total weight of the monomer, In addition to the emulsifier and the radical polymerization initiator, various chain transfer agents, pH adjusters and the like may be used in combination, if necessary, in a temperature range of 5 to 100 ° C., preferably 50 to 90 ° C., and 0.1 to 10 What is necessary is just to perform emulsion polymerization over time.

  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. 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 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 obtained by, for example, copolymerizing an acrylic monomer having a primary hydroxyl group, an acrylic monomer having a secondary hydroxyl group, and other acrylic monomers. In a manufacturing method, it can manufacture by using the acrylic monomer which has a hydrophilic group as some acrylic monomers.

  Examples of the acrylic monomer having a hydrophilic group include carboxyl group-containing acrylic monomers such as (meth) acrylic acid and 2-carboxyethyl (meth) acrylate and alkali metal salts thereof, N, Examples include tertiary amino group-containing (meth) acrylamides such as N-dimethyl (meth) acrylamide, tertiary amino group-containing (meth) acrylic esters such as dimethylaminoethyl (meth) acrylate, and quaternized products thereof. Of these, (meth) acrylic acid or dimethylaminoethyl (meth) acrylate is preferred. 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 having a hydrophilic group include various polymerization methods, and among them, a solution using an organic solvent. The radical 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. Typical examples among them include 2,2′-azobis (isobutyl). Nitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) and the like; tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxy-2- Examples thereof include peroxides such as ethylhexanoate.

  As a method for dispersing the acrylic resin (B2) having a hydrophilic group obtained by the solution radical polymerization in an aqueous medium, various methods may be mentioned, and among them, the phase inversion emulsification method may be used. preferable. 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 in the case of using an organic solvent is at least 1 weight% or more.

  As described above, the acrylic resin (B) preferably has a number average molecular weight of 5,000 to 500,000 and a weight average molecular weight of 10,000 to 1,000,000. In particular, in order to obtain an acrylic resin (B) satisfying a high molecular weight condition that the weight average molecular weight is 200,0000 or more, for example, an acrylic monomer (in combination with a vinyl monomer) present in the polymerization system Alternatively, the polymerization may be performed by lowering the number of radicals derived from the polymerization initiator, or by providing a crosslinked structure to the acrylic resin (B) during the polymerization. Further, in order to more effectively obtain the acrylic resin (B) that satisfies the molecular weight condition, the polymerization method by reducing the number of radicals generated and the method of imparting a crosslinked structure can be combined. 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.

  As a method of reducing the number of radicals generated, any one of (1) a method of reducing the amount of polymerization initiator used, (2) a method of polymerizing at a low temperature, (3) a method of extending the polymerization time, or the like A combination of these methods is effective. In addition, as a specific example of the method of (2) polymerization at a low temperature, (i) in the case of obtaining an acrylic resin (B1) in which an acrylic resin is dispersed in an aqueous medium with a dispersant such as an emulsifier, polymerization at 50 ° C. or lower Polymerization using a so-called redox initiator at a temperature, (b) When obtaining an acrylic resin (B2) in which an acrylic resin having a hydrophilic group is dispersed in an aqueous medium, polymerization is performed at a polymerization temperature of 80 ° C. or lower. Methods and the like.

  In addition, as a method for imparting the crosslinked structure, in the production method of copolymerizing an acrylic monomer having a primary hydroxyl group, an acrylic monomer having a secondary hydroxyl group, and other acrylic monomers (1) A method of copolymerization using a monomer having a plurality of vinyl groups in one molecule as a part of other acrylic monomers, (2) A silane coupling agent having a vinyl group is used in combination. And (3) a method in which a monomer having a plurality of vinyl groups in one molecule and a silane coupling agent having a vinyl group are 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 acrylic resin (B) [for example, acrylic monomer having primary or secondary 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 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 the monomers having a plurality of vinyl groups in one molecule, if the molecular chain between adjacent vinyl groups has a specific molecular weight, the water resistance is maintained without lowering the initial coating film hardness. Can be improved. Specifically, the molecular weight of the molecular chain between vinyl groups is preferably 100 or more, more preferably 100 to 700.

  Examples of the monomer having a plurality of vinyl groups in one molecule include diallyl phthalate, divinylbenzene, allyl acrylate, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene. Glycol dimethacrylate (ethylene glycol skeleton number 4 or more), polypropylene glycol dimethacrylate (propylene glycol skeleton number 1 or more), neopentyl glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 3 -Methyl 1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol Methacrylate, 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.

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

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 weight average molecular weight of 350,000 or more. 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. In particular, since a water-based floor coating excellent in old film adhesion, initial film hardness, and water resistance can be obtained, the number average molecular weight is 80,000 or more and the weight average molecular weight is 350,000 or more. The number average molecular weight is 90,000, the weight average molecular weight is more preferably 400,000 or more, the number average molecular weight is 100,000, and the weight average molecular weight is most preferably 500,000 or more. .

  However, the acrylic resin (C) may contain a component insoluble in THF as a developing solvent when the molecular weight is measured by gel permeation chromatography. For this purpose, the THF-insoluble component at 25 ° C. of the acrylic resin (C) is preferably less than 95% by weight, more preferably less than 80% by weight, and most preferably less than 60% by weight.

  The acrylic resin (C) 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 (Tgc) of the acrylic resin (C) is not particularly limited, it is particularly 30 to 75 ° 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 40-65 degreeC.

  The acrylic resin (C) can be produced, for example, by using various acrylic monomers and polymerizing under a condition that a high molecular weight acrylic resin is obtained. 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 used in the polymerization of the acrylic resin (C) include acrylic monomers having hydroxyl groups listed as monomers that can be used in the production of the acrylic resin (B) and other acrylic monomers. Any of the masses 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 an acrylic resin (C) satisfying a high molecular weight condition of a weight average molecular weight of 350,000 or more, it is the same as the method described as a method that may be used to obtain an acrylic resin system (B) satisfying a high molecular weight condition. , That is, a method for polymerizing various acrylic monomers (vinyl monomers may be used in combination) by reducing the number of radicals derived from the polymerization initiator, and an acrylic resin during the polymerization. A method of imparting a crosslinked structure to the material, a method of combining these, and the like can be used.

  As a method for reducing the number of radicals generated and a method for imparting a crosslinked structure, the same method as described in the method that may be used to obtain the acrylic resin system (B) satisfying the high molecular weight condition may be used. Can be mentioned.

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

  In the method for imparting the crosslinked structure, 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. It is preferably 0.05 to 10 parts by weight per 100 parts by weight of various acrylic monomers (vinyl monomers may be used in combination) used for the synthesis of the acrylic resin (C). More preferably, it is 1-5 parts by weight, and most preferably 0.2-2 parts by weight.

  In order to effectively obtain the acrylic resin (C) satisfying the high molecular weight condition, a plurality of vinyl groups are contained in one molecule as in the case of obtaining the acrylic resin system (B) satisfying the high molecular weight condition. Among the monomers, it is preferable that the molecular chain between adjacent vinyl groups has a specific molecular weight because the water resistance can be improved without lowering the initial coating film hardness. Specifically, the molecular weight of the molecular chain between vinyl groups is preferably 100 or more, more preferably 100 to 700.

  As a monomer having a plurality of vinyl groups in one molecule used for obtaining the acrylic resin (C) satisfying the high molecular weight condition or a silane coupling agent having a vinyl group, an acrylic satisfying the high molecular weight condition is used. Examples thereof include the same monomers and silane coupling agents used for obtaining the resin system (B).

  The weight ratio (B / C) of the acrylic resin (B) and acrylic resin (C) used in the present invention is an aqueous coating for floors that has excellent old film adhesion, recoatability, initial coating film hardness, and water resistance. Since a coating material is obtained, it is preferably 0.3 to 3, more preferably 0.4 to 2.2, and most preferably 0.7 to 1.5.

  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. 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 water-based paint for floors of the present invention is obtained by dispersing the polyisocyanate (A), the acrylic resin (B), and the acrylic resin (C) in an aqueous medium. As a method of mixing (A) with the acrylic resin (B) and the acrylic resin (C), for example, an acrylic resin (B) and an acrylic resin (C) dispersed in an aqueous medium, Examples thereof include a method in which polyisocyanate (A) or polyisocyanate (A) dispersed in an aqueous medium is added and stirred. 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.

  The mixing ratio of the polyisocyanate (A), the acrylic resin (B) and the acrylic resin (C) at this time is a water-based paint for flooring excellent in old film adhesion, recoatability, initial hardness, and water resistance. Therefore, 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 0.5 to 2.5. Is more preferable, 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 floor materials can be used as the floor material on which the water-based paint for floors of the present invention can be applied, and examples thereof include various inorganic floor materials, wooden floor materials, plastic floor materials, and the like. 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 wood materials, such as a cedar, a pine, a cypress, and a larch, Hardwood materials, such as a birch, a zelkova, a Japanese oak, a cherry tree, a walnut, a rose, a teak, and a mahogany are mentioned.

  Examples of plastic floor materials include molded articles of thermoplastic resins such as polystyrene, polycarbonate, polymethyl methacrylate, ABS resin, polyphenylene oxide, polyurethane, polyethylene, polyvinyl chloride, polypropylene, polybutylene terephthalate, and 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.

  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 coating method of the floor water-based paint of the present invention include, for example, a method of coating the floor water-based paint of the present invention on the floor material on which the old coating film exists and drying it, and the old coating film exists. After coating on the flooring material and drying, further applying the floor water-based paint on the flooring material, drying the method, coating on the flooring material on which the primer may be coated, Examples of the method include a method in which the floor water-based paint is further applied thereon 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. Above all, the floor material on which the old paint film exists and the floor material on which the primer may be applied are the inorganic floor material on which the old paint film exists and the primer on which the primer may be applied. Is preferred.

  Next, although a reference example, an example, and a comparative example explain the present invention in detail, the present invention is not limited to this. All parts and percentages in the examples 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 condenser tube and a nitrogen inlet tube, 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% was obtained by reacting at 90 ° C. for 6 hours. . Hereinafter, this is abbreviated as polyisocyanate (A-1).

Reference Example 2 [Preparation of polyisocyanate solution (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 solution (q-1).

  Next, 200 parts of polyisocyanate (p-1) and 100 parts of acrylic polymer solution (q-1) were added to a four-necked flask similar to that used for the preparation of the acrylic polymer solution (q-1). The mixture was heated to 50 ° C. under a nitrogen stream, and stirred and mixed at the same temperature for 1 hour to obtain a polyisocyanate solution having a nonvolatile content of 90% and an NCO group content of 14%. Hereinafter, this is abbreviated as a polyisocyanate solution (A-2).

Reference Example 3 [Preparation of Acrylic Resin Water Dispersion (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. 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) 12 And a mixed liquid consisting of 28 parts of 2-hydroxypropyl methacrylate (hereinafter abbreviated as 2-HPMA) was added dropwise over 3 hours. After the completion of the dropwise addition, the reaction was allowed to proceed for 2 hours, followed by cooling to 25 ° C., neutralizing with 1.5 parts of 28% ammonia water, adding deionized water to adjust the nonvolatile content to 45%, and the solid content hydroxyl value An aqueous dispersion of an acrylic resin having 80 mg KOH / g and a glass transition temperature (Tg) of 30 ° C. was obtained. Hereinafter, this is abbreviated as an acrylic resin aqueous dispersion (B-1).

Reference Examples 4 to 7 [Preparation of acrylic resin aqueous dispersions (B-2) to (B-5)]
Acrylic resin aqueous dispersions (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 resin aqueous dispersions (RB-1) to (RB-3)]
Acrylic resin aqueous dispersions (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 resin aqueous dispersions (C-1) to (C-3)]
Acrylic resin aqueous dispersions (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 resin aqueous dispersions (RC-1) to (RC-3)]
Acrylic resin aqueous dispersions (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. Subsequently, 290 parts of an acrylic resin aqueous dispersion (B-1), 290 parts of an acrylic resin aqueous dispersion (C-1), “BYK-346” (leveling agent manufactured by BYK Chemie), 8.3 parts, 4.8 parts of 10% aqueous solution of “Primal RM-8W” (Rohm & Haas thickener), 1.1 parts of 25% aqueous solution of dimethylethanolamine, “BYK-028” (antifoam made by BYK Chemie) 16 parts of a 10% aqueous solution and 3.3 parts of diethylene glycol dibutyl ether were added and stirred to obtain an aqueous base paint component (D-1) having a non-volatile content of 55%.

Reference Examples 18 to 23 [Preparation of water base paint main component (D-2) to (D-7) for floor]
Instead of the acrylic resin water dispersion (B-1) and the acrylic resin water dispersion (C-1), the acrylic resin water dispersions (B-2) to (B-5) and the acrylic resin water dispersion Except for using the liquids (C-2) to (C-3) in the combinations shown in Tables 5 (1) to (3), the same as in Reference Example 17, the water base paint main component (D-2) ) To (D-7) were obtained.

Reference Examples 24 to 28 [Preparation of water base paint main ingredient components for comparison (RD-1) to (RD-5)]
Instead of the acrylic resin aqueous dispersion (B-1) and the acrylic resin aqueous dispersion (C-1), the acrylic resin aqueous dispersions (RB-1) to (RB-3) and the acrylic resin aqueous dispersion Comparative floor aqueous paint main component (RD) in the same manner as in Reference Example 17 except that liquids (RC-1) to (RC-3) were used in combinations shown in Tables 6 (1) to (2). -1) to (RD-5) were obtained.

Example 1
Molar ratio (NCO) of the isocyanate group (NCO) in the polyisocyanate solution (A-2) and the hydroxyl group (OH) in the acrylic resin aqueous dispersion (B-1) and the acrylic resin aqueous dispersion (C-1). / OH) is mixed so that 6.7 parts of the polyisocyanate solution (A-2) and 100 parts of the water-based paint main component (D-1) for flooring are mixed, and the non-volatile content becomes 50%. As described above, dilution with water was performed to obtain a white aqueous paint (E-1).

  Using the obtained white water-based paint (E-1), an initial coating hardness test, an old coating adhesion test, a recoat adhesion test, and a water resistance test were conducted 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 following floor paints (s-1) to (s-6), which are old paint films, are applied to a 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, drying at 60 ° C. for 24 hours, and further drying for 2 weeks under the conditions of an air temperature of 25 ° C. and a humidity of 60% RH. S-1) to (S-6) are obtained. Next, these test base materials for evaluation (S-1) to (S-6) were used for 1,000 hours using a sunshine super long life weather meter (model number WE-L-SUN-DCHD, manufactured by Suga Test Instruments Co., Ltd.). The following coating materials for floor coating (s-1) to (s-6) were applied and the old coating film adhesion evaluation test base materials (S-1 ') to (S -6 '). 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)
(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 (Atomics)
(S-6): Water-based acrylic resin coating amount floor top # 1000 (manufactured by Atomics)

-Old paint film adhesion test: A white base water-based paint (E-1) was applied to a slate plate and the old paint film adhesion evaluation test substrates (S-1 ') to (S-6'). An old paint film adhesion test was conducted using a sample coated with a brush so that the coating amount was 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 old paint film adhesion test, 100 squares were created by cutting with a cutter knife at intervals of 1 mm in length and breadth, and a paint film peeling test was performed with a cellophane adhesive tape. Evaluation is based on the number of remaining paint films, slate plates, adhesion between deteriorated paint films of paint film and old paint film adhesion evaluation test substrates (S-1 ′) to (S-6 ′). evaluated. Those with 95 or more remaining can be evaluated as having good adhesion.

-Recoating property test: White floor water-based paint (D-1) was applied to the slate plate and the coating of the test base materials for evaluation (S-2) and (S-6) with a brush with a coating amount of 200 g / m. ² and then dried for 8 hours under conditions of an air temperature of 25 ° C. and a humidity of 60% RH, one day dried, and one dried for 3 days. D-1) was applied, and an adhesion test was performed using a sample that was dried for 3 days under conditions of an air temperature of 25 ° C. and a humidity of 60% RH. This adhesion test was a recoat property evaluation test. A cut was made with a cutter knife at intervals of 1 mm in length and breadth to create 100 cells, and a peel 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: A white floor water-based paint (E-1) is placed on a slate plate, the old paint film adhesion test substrate (S-1 ') and the deteriorated paint film of (S-4'). Painted with a brush to an application amount of 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 following evaluation criteria were used to determine whether or not blisters were generated when the samples were dried for 7 days under conditions of an air temperature of 25 ° C. and a humidity of 60% RH and dipped in water at a water temperature of 25 ° C. for 1 day. It was evaluated with. 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 Table 6.

Claims (14)

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 20-40 mg KOH / g acrylic resin (B) and a weight average molecular weight of 350,000 or more and a hydroxyl value of 0-15 mg KOH / g acrylic resin (C) are dispersed in an aqueous medium. A characteristic water-based paint for floors. 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, wherein the acrylic resin having a value of 25 to 35 mgKOH / g and the acrylic resin (C) is an acrylic resin having a hydroxyl value of 0 to 12 mgKOH / g. The water base for floors according to claim 1, wherein the glass transition temperature (Tgb) of the acrylic resin (B) is 15 to 70 ° C, and the glass transition temperature (Tgc) 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 molar ratio (NCO / OH) of the isocyanate group (NCO) in the polyisocyanate (A), the hydroxyl group in the acrylic resin (B) and the total hydroxyl group (OH) in the acrylic resin (C) is 0.5. The floor-use water-based paint according to claim 1, which is ˜2.5. The acrylic resin (B) is an acrylic resin having a number average molecular weight of 5,000 to 500,000 and a weight average molecular weight of 10,000 to 1,000,000, and the acrylic resin (C) is a number average molecular weight of 80,000. The floor paint according to any one of claims 1 to 5, which is an acrylic resin having a weight average molecular weight of 350,000 or more. The water base for floors according to claim 6, wherein the glass transition temperature (Tgb) of the acrylic resin (B) is 25 to 60 ° C, and the glass transition temperature (Tgc) of the acrylic resin (C) is 40 to 65 ° C. paint. The water-based paint for flooring according to claim 6, wherein the weight ratio (B / C) of the acrylic resin (B) and the acrylic resin (C) is in the range of 0.4 to 2.2. 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 Claim 6. A floor coating method comprising: coating the floor water-based paint according to any one of claims 1 to 9 on a floor material on which an old coating film exists and drying the floor paint. The water-based floor paint according to any one of claims 1 to 9 is applied onto a floor material on which an old coating film is present, dried, and then further coated with the water-based floor paint. A floor coating method characterized in that it is worked and dried. The floor coating method according to claim 10 or 11, wherein the floor material in which the old coating film exists is an inorganic floor material in which the old coating film exists. The water-based paint for floors according to any one of claims 1 to 9 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 13, wherein the floor material to which the primer may be coated is an inorganic floor material to which the primer may be coated.