JP2023018554A - Aqueous coating material composition for substrate adjustment, and substrate adjustment method and coating material finishing structure using the same - Google Patents

Abstract

To provide an aqueous coating material composition for substrate adjustment which is excellent in quick drying property and low temperature curability, has both water vapor permeability and water-shielding property, has sufficient elongation physical property and substrate followability, and has viscosity and a TI value suitable for construction by a roller brush.SOLUTION: An aqueous coating material composition for substrate adjustment is composed of crosslinked type acrylic resin-based emulsion having a glass transition temperature of -20 to 10°C, nano-composite emulsion in which a micelle with a particle diameter of 60-120 nm formed of an acrylic resin containing one or two or more silica particles with a primary particle diameter of 15-30 nm and an emulsifier is dispersed in water, a water-soluble cationized polymer, a volatile base, a filler, an organic thickener, a film formation auxiliary and a pigment, and has a pH of the whole composition of 9.5-11.5.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a base preparation water-based coating composition used for the purpose of adjusting the surface of a base on which a coating finishing material is applied, a base preparation method using the same, and a coating finishing structure.

BACKGROUND ART Conventionally, a coating material finish applied to an outer wall of a building or the like is finished using a substrate conditioning material or an undercoat material, and if necessary, an intermediate coating material and a top coating material.

Patent Document 1 proposes a base conditioning material (I) containing a copolymer aqueous dispersion (A) having a glass transition temperature of −20° C. or lower, and on a coating film of the base conditioning material (I), An aqueous copolymer dispersion (B) having a copolymer glass transition temperature of −60 to 0° C. and an aqueous copolymer dispersion (C) having a copolymer glass transition temperature of 15 to 50° C. were solidified. A painting finishing method characterized by applying a topcoat paint (II) containing a partial mass ratio of 20/80 to 80/20 in the (B) / (C) ratio has been proposed. It is shown to be able to follow and to be excellent in waterproofness. However, water-based compositions such as the base conditioning material and the topcoat of Patent Document 1 cause fusion of the resin due to the evaporation of the solvent water during the coating film formation process, but the evaporation rate of water is slow. In addition, there is a problem that it takes time to form a coating film and there are cases where it does not dry quickly. In addition, in a low temperature environment where the evaporation rate of water is particularly low, the coating film is formed with insufficient drying, resulting in poor coating film formation, and whitening of the coating film due to the difference in the refractive index of light between water and resin. There was a problem that it may occur.

In order to solve the above-mentioned problems, Patent Document 2 describes a storage-stable aqueous binder composition suitable for a traffic paint having a quick drying property, comprising (a) an anionically stabilized aqueous dispersion of a polymer, ( b) a water-soluble polyfunctional amine polymer; and (c) a suspension or dispersion of phyllosilicate in a volatile base, wherein the concentration of said phyllosilicate is the total weight of said suspension or said dispersion. a suspension or dispersion of a phyllosilicate in a volatile base, wherein the volatile base is from 1% to 18% by weight, based on is used in an amount such that substantially all of said polyfunctional amine polymer has a pH in the non-ionic state.

JP-A-2008-12373 Japanese Patent Publication No. 2018-532834

However, the storage-stable aqueous composition of Patent Document 2 has a problem that it may not have water vapor permeability when it does not contain aggregates, etc., and this may cause blistering and peeling of the coating film. I have a problem.

In addition, since the composition of Patent Document 2 contains a synthetic phyllosilicate that is an inorganic thickener, there is a problem that pre-mixing is required at the time of production, which is time-consuming. High-speed stirring may be required, resulting in a problem of high cost. In addition, if a clay-based material such as synthetic phyllosilicate is added to the composition, the color of the material will be added to the composition, making it difficult to adjust the color tone or adversely affecting the concealing properties and the color development of the topcoat material. I have a problem.

The problem to be solved by the present invention is that it has quick-drying properties, is therefore excellent in curability in a low-temperature environment, and has good water vapor permeability to prevent blistering and peeling of the coating film that may occur due to moisture contained in the substrate. In spite of having the water vapor permeability, it has water impermeability, also has substrate followability, is excellent in storage stability, and premixing and long-time high-speed stirring are required when blending the thickener. To provide a base preparation water-based coating material composition having a viscosity and a TI value (thixotropic index) suitable for application by a roller brush, a base preparation method using the same, and a coating finishing structure. .

In order to solve the above problems, the invention according to claim 1 comprises a crosslinked acrylic resin emulsion having a glass transition temperature of −20 to 10° C. and one or more silica particles having a primary particle diameter of 15 to 30 nm. A nanocomposite emulsion in which micelles having a particle size of 60 to 120 nm formed by an acrylic resin and an emulsifier are dispersed in water, a water-soluble cationic polymer, a volatile base having a boiling point of 100 ° C. or less, a filler, an organic A composition comprising a system thickener, a film-forming aid, and a pigment,
The weight ratio of the solid content of the crosslinked acrylic resin emulsion to the solid content of the nanocomposite emulsion is 4 to 15:1,
The silica particles are 10 to 20 parts by weight in 100 parts by weight of the nanocomposite emulsion,
The amount of the water-soluble cationized polymer is 0.2 to 1.2 parts by weight in 100 parts by weight of the entire composition,
the pH of the entire composition is 9.5 to 11.5;
To provide a water-based coating material composition for base preparation characterized by:

The invention according to claim 2 provides the water-based coating material composition for base preparation according to claim 1, wherein the water-soluble cationic polymer is a polyalkyleneimine compound.

The invention according to claim 3 is characterized in that the volatile base comprises any one or a mixture of two or more of ammonia, a C ₁ -C ₄ lower alkylamine, and dimethylaminomethanol. A water-based coating material composition for base preparation according to claim 1 or claim 2 is provided.

The invention according to claim 4 is characterized in that the organic thickener is a urethane-modified polyether having a weight average molecular weight (Mw) of 10,000 to 35,000. In one aspect, a water-based coating material composition for base preparation is provided.

In the invention according to claim 5, the viscosity of the composition is 60 to 150 Pa s / 23 ° C. at 2 rpm of the BH type viscometer, and the viscosity at 2 rpm of the BH type viscometer is obtained by dividing the viscosity at 20 rpm. 5. The water-based coating material composition for base preparation according to any one of claims 1 to 4, characterized in that the composition has a TI value of 4 to 7.

In the invention according to claim 6, the water-based coating material composition for base preparation according to any one of claims 1 to 5 is applied to the base at least twice with a coating thickness of 0.15 to 0.5 mm. To provide a base preparation method characterized by attaching.

The invention according to claim 7 is a base preparation water-based coating material composition layer formed by applying the base preparation water-based coating material composition according to any one of claims 1 to 5, and a topcoat material layer formed by applying a topcoat material at least once on the base conditioning water-based coating material composition layer.

The base preparation water-based coating material composition of the present invention has the effect of having quick-drying properties. This is because anionically charged micelles (anionic micelles) containing acrylic resin polymers in crosslinked acrylic resin emulsions and nanocomposite emulsions and water-soluble cationized polymers are aggregated by electrical interaction to form acrylic resins. It is presumed that this is based on promoting fusion and fixation of the polymer. Since the quick-drying property works even in a low-temperature environment where water in the composition does not easily evaporate, it suppresses whitening of the coating film and poor coating film formation that can occur when using a general water-based coating material composition in a low-temperature environment. has the effect of In addition, the water-based coating material composition for base preparation of the present invention has a sufficient time (pot life) that can be applied with good workability even in high temperature environments such as summer, and has good coating workability. It has the effect of having

In addition, the water-based coating material composition for base preparation of the present invention forms a dense coating film in spite of being a water-based coating material composition, and contains nano-sized silica particles. It has the effect of having water. It is speculated that the nano-sized silica particles are dispersed in the coating film and form a pore structure of a size that cannot be visually confirmed, resulting in a porous coating film that allows water vapor to permeate.

Due to the water vapor permeability, the moisture contained in the substrate is released as water vapor through the coating film formed by the composition, or moves in the continuous direction of the coating film, so that the water vapor pressure is locally applied to a part of the coating film. In addition, even if moisture is continuously supplied to the substrate for some reason and the moisture accumulates at the interface with the coating film, the moisture is released as water vapor to the outside of the coating film or in the continuous direction of the coating film. Therefore, there is an effect that the occurrence of blistering and peeling of the coating film is suppressed (blistering resistance).

In addition, since the water-based coating material composition for base preparation of the present invention uses a crosslinked acrylic resin emulsion having a glass transition temperature of −20 to 10° C., it has the effect of being excellent in elongation physical properties and base conformability. , Even if a topcoat material conforming to the provisions of JISA 6909 architectural finish coating material is applied on the water-based coating material composition for base preparation of the present invention to form a coating material finish structure, the coating film will not peel off or crack. has the effect of making it difficult for

In addition, since the water-based coating material composition for base preparation of the present invention uses an organic thickener instead of an inorganic thickener, it does not require premixing or high-speed stirring for a long time during production, resulting in a low There is an effect that it is a cost. In addition, the viscosity of the water-based coating material composition for base preparation of the present invention is adjusted to 60 to 150 Pa·s/23°C and the TI value to 4 to 7 with the organic thickener, so that construction tools such as roller brushes can be used. can be applied to a vertical substrate such as the outer wall of a building with good workability so that the thickness of one application is 0.15 to 0.5 mm.

In addition, in the substrate preparation method of claim 6, both excellent water vapor permeability and water impermeability are sufficiently exhibited by applying at least two times with a coating thickness of 0.15 to 0.5 mm. There is an effect that the coating thickness of only can be secured with good coating workability without causing sagging. In addition, even if the substrate has a large unevenness, for example, an unevenness exceeding 0.5 mm, there is an effect that the large unevenness of the substrate can be adjusted without impairing the water vapor permeability and water impermeability.

The coating material finishing structure according to claim 7 has the base conditioning material layer which is excellent in water vapor permeability and base conformability, so that there is an effect that swelling and peeling are less likely to occur. As described above, the base conditioning material layer has water vapor permeability, and the water vapor permeability allows water vapor to permeate not only in the thickness direction of the coating film but also in the continuous direction of the coating film. Therefore, not only when the topcoat material layer forming the coating material finish structure has water vapor permeability, but also when it does not have water vapor permeability, water vapor related to moisture contained in the base can be released in the continuous direction of the coating film. In addition, even if moisture is continuously supplied to the substrate for some reason and accumulates at the interface with the coating film, the moisture can be removed by steam. As a result, it is possible to escape in the continuous direction of the coating film, so there is an effect that swelling and peeling do not occur due to these influences.

The present invention will be described in detail below.

The water-based coating material composition for base preparation of the present invention is a crosslinked acrylic resin emulsion having a glass transition temperature of −20 to 10° C. and an acrylic resin containing one or more silica particles having a primary particle diameter of 15 to 30 nm. A nanocomposite emulsion formed by dispersing micelles with a particle size of 60 to 120 nm formed by a resin and an emulsifier in water, a water-soluble cationic polymer, a volatile base having a boiling point of 100 ° C. or less, a filler, and an organic additive. A composition comprising a viscosity agent, a film-forming aid, and a pigment, wherein the weight ratio of the solid content of the crosslinked acrylic resin emulsion to the solid content of the nanocomposite emulsion is 4 to 15:1, and the silica The particles are 10 to 20 parts by weight in 100 parts by weight of the nanocomposite emulsion, the amount of the water-soluble cationic polymer is 0.2 to 1.2 parts by weight in 100 parts by weight of the entire composition, and the pH of the composition as a whole is is 9.5 to 11.5. of additives can be blended.

<Crosslinked acrylic resin emulsion>
The crosslinked acrylic resin emulsion used in the present invention is a main component constituting the water-based coating material composition for base preparation of the present invention, and the acrylic resin emulsified by an emulsifier to form micelles is an acrylic resin such as a hydrazine derivative. It is a water-based resin that is dispersed in water together with a water-soluble cross-linking agent to form an emulsion. As the emulsifier, it is possible to use an anionic emulsifier that has a hydrophilic group such as carboxylic acid, sulfonic acid, or phosphoric acid and is anionically charged in an aqueous solution. The micelles that make up the resin emulsion are anionically charged.

Examples of acrylic resins that can be used include acrylate-based copolymer resins, vinyl acetate/acrylate-based copolymer resins, and silicon-modified acrylic resins. Examples of acrylic monomers for acrylic resins include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, t-butyl acrylate, hexyl acrylate, and 2-ethylhexyl. Acrylate, octyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, n-amyl acrylate, isoamyl acrylate, lauryl acrylate, stearyl acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl ( meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl ( meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl ( Meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxypropyl (meth)acrylate, ethoxypropyl (meth)acrylate, etc. can be used. It can be used either singly or in combination of two or more. Other unsaturated monomers include styrene derivatives such as styrene, α-methylstyrene, chlorostyrene, vinyltoluene, methoxystyrene; (meth)acrylic acid, fumaric acid, maleic acid, maleic anhydride, itaconic acid, anhydride; Carboxyl group-containing monomers such as itaconic acid and crotonic acid; (meth)acrylic acid, crotonic acid, itaconic acid; 2-hydroxyethyl (meth)acrylate and 2(3)-hydroxypropyl (meth)acrylate, Hydroxy group-containing monomers such as 4-hydroxybutyl acrylate, allyl alcohol, mono (meth) acrylic acid esters of polyhydric alcohols; (meth) acrylamide and amide group-containing monomers such as maleamide; 2-aminoethyl ( meth) acrylate, dimethylaminoethyl (meth) acrylate, 3-aminopropyl (meth) acrylate, 2-butylaminoethyl (meth) acrylate, amino group-containing monomers such as vinylpyridine; glycidyl (meth) acrylate, Allyl glycidyl ether, epoxy group-containing monomers and oligomers obtained by reacting an epoxy compound having two or more glycidyl groups with an ethylenically unsaturated monomer having an active hydrogen atom; vinyltrimethoxysilane, vinyltriethoxy silane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane, 2 -(meth)acryloxyethyltriethoxysilane, 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, 3-(meth)acryloxypropylmethyldipropoxysilane, 3 -Alkoxysilyl group-containing monomers such as (meth)acryloxybutylphenyldimethoxysilane, 3-(meth)acryloxypropyldimethylmethoxysilane, and 3-(meth)acryloxypropyldimethylmethoxysilane; in addition, vinyl acetate, Vinyl chloride, and further ethylene, butadiene, acrylonitrile, dialkyl fumarate, etc. can be used, and they can be used singly or in combination of two or more.

Cross-linking agents include carbonyl hydrazine adipic acid dihydrazide, glutaric acid dihydrazide, isophthalic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide. or hydrazine derivatives such as ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, and butylene-1,4-dihydrazide, which are alkyl hydrazides. can be used as The content of the cross-linking agent is preferably 0.05 to 2.0 parts by weight per 100 parts by weight of the cross-linkable acrylic resin emulsion. If it exceeds 0 parts by weight, the coating film may become too dense and the water vapor permeability may decrease.

The glass transition temperature of the acrylic resin constituting the crosslinked acrylic resin emulsion of the present invention is preferably -20 to 10°C. If the glass transition temperature is less than −20° C., cracks may occur in the topcoat material applied on top of the water-based coating material composition for base preparation of the present invention, depending on the topcoat material. This is because the glass transition temperature of common topcoat materials is often about 20 ° C., and the difference in glass transition temperature between the water-based coating material composition for base preparation of the present invention and the topcoat material exceeds about 30 to 40 ° C. This is based on the fact that the topcoat material cannot follow the movement of the water-based coating material composition for base preparation of the present invention that follows the movement of the base, and cracks may eventually occur in the topcoat material. The cracks tend not to occur when the topcoat material is applied relatively thickly to about several millimeters like the coating material, but when it is applied relatively thinly to about several tens of microns like the paint. It tends to occur remarkably when it is done. On the other hand, if the glass transition temperature of the acrylic resin constituting the crosslinked acrylic resin-based emulsion of the present invention is higher than 10° C., the followability to the base may deteriorate. The glass transition temperature referred to here is a value measured by a differential scanning calorimetry (DSC). The solid content of the crosslinkable acrylic resin emulsion of the present invention is preferably 10 to 30 parts by weight in 100 parts by weight of the water-based coating material composition for base preparation. On the other hand, if it exceeds 30 parts by weight, the coating workability is lowered.

<Nanocomposite emulsion>
The nanocomposite emulsion used in the present invention is an acrylic resin containing one or more silica particles having a primary particle size of 15 to 30 nm, which is emulsified by the action of an emulsifier to form micelles of 60 to 120 nm. is a water-based resin that is dispersed in water. As the emulsifier, it is possible to use an anionic emulsifier which has a hydrophilic group such as carboxylic acid, sulfonic acid, or phosphoric acid and is anionically charged in an aqueous solution. The constituent micelles are anionically charged.

The nanocomposite emulsion is contained for the purpose of imparting water vapor permeability to the water-based coating material composition for base preparation of the present invention. It is presumed that this is achieved by forming a permeable pore structure and allowing water vapor to move along the surface of the silica particles.

The acrylic resin described in paragraph [0026] can be used. In addition, the silica particles may have a nano-sized primary particle diameter of 15 to 30 nm, and the SiOH groups present on the particle surface are unmodified, and those surface-modified with amino groups, carboxyl groups, etc. are used. can be used, and is not particularly limited. As a method for producing an acrylic resin containing nano-sized silica particles, for example, mini-emulsion polymerization is used to generate submicron-sized monomer oil droplets (mini-emulsion) containing the silica particles by a method such as ultrasonic irradiation. However, there is a method in which the monomer oil droplets are polymerized as they are to convert them into submicron-sized polymer fine particles. In addition, there is also a method of growing a polymer on the surface of the silica particles by graft polymerization, in which the surface of the silica particles is modified with an acrylic monomer-based silane coupling agent, emulsion polymerization is performed, and core-acrylic shell particles are obtained. obtained by growing a shell polymer layer in When preparing an acrylic resin containing nano-sized silica particles by these methods, it may contain only one silica particle or may contain two or more silica particles, and the weight ratio of the acrylic resin to the silica particles is The weight ratio should be 1:3 to 3:1 on average, and this weight ratio can be controlled by the production method, the type of acrylic resin, the additives used, and the like. In addition, the amount of the silica particles in 100 parts by weight of the nanocomposite emulsion is preferably 10 to 20 parts by weight. Physical properties and water impermeability may deteriorate.

The amount of the nanocomposite emulsion to be blended is preferably such that the weight ratio of the solid content of the crosslinked acrylic resin emulsion to the solid content of the nanocomposite emulsion is 4 to 15:1. If the solids content of the nanocomposite emulsion is less than this range, the content of nano-sized silica particles may be reduced and the water vapor permeability may be impaired. As a result, the content of the silica particles becomes excessive, and the denseness of the coating film may be lowered, thereby lowering the water impermeability.

<Water-soluble cationized polymer>
The water-soluble cationic polymer used in the present invention is blended for the purpose of imparting quick-drying properties. By electrically interacting with charged micelles (anionic micelles), it promotes cohesion of resins without waiting for fusion of resins due to evaporation of water in the coating film formation process of general water-based compositions. promotes the film-forming reaction. In the water-soluble cationic polymer, all the cationic functional groups are apparently in a neutral state due to the interaction with the volatile base described later in the state before the composition is applied, and the anionic micelles and the electricity chemical interactions and is controlled so that the composition does not agglomerate during manufacture and storage.

The water-soluble cationic polymer of the present invention is not particularly limited as long as it is a polymer having a cationic functional group. Compounds, basic nitrogen-containing polymers obtained by modifying these compounds, and the like can be used. A polyalkyleneimine compound obtained by ionically polymerizing an imine compound is preferred, and polyethyleneimine obtained by polymerizing ethyleneimine is particularly preferred because it has a large ratio of cationic functional groups in the molecule. The molecular weight preferably has a weight average molecular weight (Mw) of 600 to 200,000 as measured by gel permeation chromatography (GPC), and the higher the weight average molecular weight (Mw), the higher the viscosity as an additive. Since it is difficult to handle, it is more preferable that the weight average molecular weight (Mw) is 600 to 100,000. If it is less than 600, the cohesiveness with the anionic micelles in the crosslinked acrylic resin emulsion and nanocomposite emulsion may be reduced, resulting in a decrease in quick-drying properties. tends to be difficult to handle due to its high viscosity.

The amount of the water-soluble cationic polymer blended is appropriately adjusted according to the type, molecular weight, and ratio of cationic functional groups in the molecule. It is preferably 0.2 to 1.2 parts by weight in 100 parts by weight of the water-based coating material composition for adjustment. If it is less than 0.2 parts by weight, the quick-drying property may deteriorate, and if it exceeds 1.2 parts by weight, the pot life may be shortened and the workability of coating may be adversely affected.

<Volatile base>
The volatile base used in the present invention interacts with the cationic functional group of the water-soluble cationic polymer during the period from the time the water-based coating material composition for base preparation of the present invention is produced until it is applied to the base. By doing so, the cationic functional group appears to be in a neutral state, suppressing aggregation with the anionic micelles in the crosslinked acrylic resin emulsion and nanocomposite emulsion, and improving the storage stability of the composition. Blend. Volatile base refers to a base that easily volatilizes into the atmosphere at standard atmospheric pressure (1 atm or 760 mm/Hg), and includes ammonia, morpholine, lower alkylamines having a carbon number of C ₁ to C ₅ , dimethylaminomethanol, 2- Examples include dimethylaminoethanol, N-methylmorpholine, ethylenediamine, or mixtures thereof, and the volatile base is usually in the form of an aqueous solution. In the water-based coating material composition for base preparation of the present invention, it is more preferable to use a volatile base having a boiling point of 100 ° C. or less in order to achieve sufficient quick drying, specifically ammonia, carbon number C ₁ - _C4 lower alkylamines, dimethylaminomethanol and the like. In particular, aqueous solutions of ammonia are inexpensive and low cost.

The amount of the volatile base to be blended is preferably such that the water-based coating composition for base preparation of the present invention has a pH of 9.5 to 11.5, and depends on the basicity of the volatile base used. . If the pH is less than 9.5, the storage stability may decrease. In some cases, the odor of the volatilized base becomes stronger, adversely affecting the working environment.

In addition, since the volatile base lowers the freezing point of water when dissolved in water, it also has an antifreezing effect in the water-based base preparation coating material composition of the present invention, which uses water as a solvent. This effect has the effect of synergistically improving the antifreezing effect when used in combination with a commercially available antifreeze agent.

<Filling material>
The filler of the present invention has an average particle size D50 (particle size of 50% accumulated by weight) of less than 100 μm, and is blended in an amount of 5 parts by weight or less per 100 parts by weight of the entire composition as a thickener. It does not include synthetic layered silicates, which are also treated. It is blended for the purpose of adjusting the viscosity and applicability of the composition, and can be used with heavy calcium carbonate, clay, kaolin, talc, precipitated barium sulfate, barium carbonate, silica sand powder, etc. Among them, heavy calcium carbonate is inexpensive. Cost burden can be reduced. The amount of the filler compounded is preferably 25 to 45 parts by weight, more preferably 30 to 40 parts by weight, based on 100 parts by weight of the entire base preparation water-based coating material composition. If the amount exceeds 45 parts by weight, the viscosity of the composition may become high, resulting in poor coating workability. On the other hand, if it is less than 30 parts by weight, the opacifying property may deteriorate depending on the color tone.

<Organic Thickener>
The organic thickener of the present invention is blended for the purpose of improving coating workability and preventing aggregation of the composition during storage by improving water retention, and the water-based coating material composition for base preparation of the present invention. is not particularly limited as long as it has a viscosity of 60 to 150 Pa·s/23° C. and a TI value of 4 to 7, and water-soluble cellulose ether, urethane-modified polyether, polycarboxylic acid, or a mixture thereof etc. can be used. From the viewpoint of storage stability, the water-based coating material composition for base preparation of the present invention preferably maintains the pH of the composition within the range of 9.5 to 11.5. It is preferable to use a urethane-modified polyether that does not easily affect pH. Of course, even if other organic thickeners that can affect the pH such as lowering the pH are used, the pH of the composition can be adjusted from 9.5 to 11.5 by adjusting the blending amount of the volatile base. If it can be adjusted within the range of 5, both can be used without problems.

The amount of the organic thickener of the present invention is preferably 0.1 to 5.0 parts by weight in 100 parts by weight of the water-based coating material composition for base preparation, and if it is less than 0.1 part by weight, a sufficient thickening effect is obtained. is not obtained, causing sagging when the composition is applied. In addition, the organic thickener preferably has a weight average molecular weight (Mw) of 10,000 to 35,000 as measured by gel permeation chromatography (GPC), and is less than 10,000. The viscosity effect may be insufficient, and if it exceeds 35,000, the viscosity may be excessively increased and the coating workability may be adversely affected.

In addition, there are inorganic thickeners such as silicates, metal silicates, montmorillonite, and colloidal alumina as thickeners used in water-based compositions. In some cases, it is necessary to prepare a mill base by pre-mixing it before mixing it with the water-based resin, and it is necessary to stir at high speed for a long time to uniformly disperse it, which is laborious and costly. In addition, even if such an inorganic thickener is used, it may cause mineral-derived mud-like coloring, which may adversely affect the concealability of the undercoat and the color development of the topcoat material. Therefore, it is preferable to use an organic thickener in the present invention.

<Film deposition aid>
The film-forming aid used in the present invention is blended for the purpose of promoting the fusion of acrylic resin polymer particles in the crosslinked acrylic resin emulsion and nanocomposite emulsion and forming a uniform film, and ethylene glycol. Diethyl ether, ethylene glycol monoethyl ether acetate, benzyl alcohol, butyl cellosolve, ester alcohol, mixtures thereof, and the like can be used. The amount of the film-forming aid is preferably 0.5 to 10 parts by weight in 100 parts by weight of the water-based coating material composition for base preparation. If it exceeds 10 parts by weight, the surface of the coating film becomes sticky and dirt tends to adhere.

<Pigment>
Pigments used in the present invention include inorganic pigments such as titanium oxide, zinc oxide, carbon black, ferric oxide (red iron oxide), lead chromate, yellow lead, and yellow iron oxide. Titanium is excellent in the hiding power of the base and can be used as a main pigment for imparting the hiding power because of its white color.

In addition to the above, the water-based coating material composition for base preparation of the present invention contains antifoaming agents, preservatives, dispersants, anti-algae and anti-mold agents, and anti-freezing agents that are generally used in water-based compositions. preferably.

The base preparation water-based coating composition of the present invention can be applied to mortar bases, concrete bases, panel (ALC panel) bases made of autoclave-cured lightweight cellular concrete, ceramic siding bases, paint bases, and the like. Examples of the coating substrate include acrylic resin-based, acrylic urethane resin-based, polyurethane resin-based, fluororesin-based, silicon acrylic resin-based, vinyl acetate resin-based, and epoxy resin-based coatings. In order to maintain sufficient adhesion with the water-based coating material composition for base preparation of the present invention, it is desirable to perform a base treatment suitable for each base to prepare a clean and dry base.

In addition, some of the substrates have a portion where the panel abutment portion or the joint portion is sealed. In order to solve this problem, before applying the base preparation water-based coating material composition of the present invention, a flexible and breathable fiber sheet such as a non-woven fabric is attached, so that it can be coated on it. It is possible to suppress the occurrence of cracks in the base preparation water-based coating material composition and the coating material finish structure of the present invention. For attaching the nonwoven fabric, for example, a composition obtained by adding 25 to 45 parts by weight of fibrous aggregate and 5 to 10 parts by weight of water to 100 parts by weight of the water-based coating material composition for base preparation of the present invention and mixing them is used. be able to. An example of the fibrous aggregate is wollastonite ore, and a fiber length of 100 to 1500 μm and a fiber diameter of 20 to 80 μm are preferable because the composition can be well impregnated into the fiber sheet.

A roller brush can be used to apply the water-based coating material composition for base preparation of the present invention, which is suitable for application to a thickness of 0.15 to 0.5 mm. It is needless to say that other coating tools may be used as long as they can be coated in a thickness of 0.15 to 0.5 mm.

The water-based coating material composition for base preparation of the present invention more preferably has a viscosity of 60 to 150 Pa·s/23° C. and a TI value of 4 to 7 for ease of application and prevention of sagging. The viscosity is measured using a BH viscometer TVB-10 (trade name, manufactured by Toki Sangyo Co., Ltd.) at a rotation speed of 2 rpm, and the TI value is a value measured according to JISA 6024. When the temperature is high, the viscosity tends to decrease and sagging tends to occur. On the other hand, when the temperature is low, the viscosity increases and the coating workability decreases, so the various physical properties evaluated below are significantly reduced. The viscosity can be adjusted by adding an appropriate amount of water within the range that does not occur. In order to prevent these problems, it is preferable to use at an air temperature of 5 to 35°C.

In addition, the water-based coating material composition for base preparation of the present invention has a thickness of 0.15 to 0.5 mm per application, and a total thickness of 0.3 to 1.0 mm when applied twice or more. If the thickness is less than 0.3 mm, the water impermeability may deteriorate, and if it exceeds 1.0 mm, the water vapor permeability may deteriorate. Also, when the thickness of one application exceeds 0.5 mm, the quick-drying property may deteriorate. In addition, when the substrate is porous and the applied composition is strongly absorbed, it is necessary to increase the number of applications to obtain a sufficient film thickness.

Hereinafter, the effects of the water-based coating material composition for base preparation of the present invention, namely quick-drying property, storage stability, water vapor permeability and water impermeability, will be described in detail.

The quick-drying property of the water-based coating material composition for base preparation of the present invention is due to the electrical interaction between the anionic micelles containing the acrylic resin polymer in the crosslinked acrylic resin emulsion and the nanocomposite emulsion and the water-soluble cationized polymer. The mechanism is considered to be that the anionic micelles and the water-soluble cationized polymer in the state of electrical interaction are aggregated to promote fusion and fixation of the polymer. In the coating film formation process of conventional water-based coating compositions, resin fusion occurs due to evaporation of water. It is thought that the quick-drying property can be obtained because the fusion of the resin is accelerated without any heat.

In addition, although there was a problem that the above-mentioned quick-drying property may occur even during the production and storage of the water-based coating material composition for base preparation of the present invention, the present inventors found that the composition contains a volatile base having a boiling point of 100 ° C. or less. This problem was successfully solved by blending The water-based coating material composition for base preparation of the present invention is prepared by adding a water-soluble cationic polymer in the presence of a crosslinked acrylic resin emulsion and a nanocomposite emulsion, and the water-soluble cationic polymer is added. By adding a volatile base in advance to make the pH of the entire composition basic in the range of 9.5 to 11.5, the volatile base becomes soluble when the water-soluble cationic polymer is added. interacting with the cationic functional groups of the water-soluble cationic polymer, causing the water-soluble cationic polymer to behave as neutral in appearance. As a result, the water-soluble cationic polymer is designed not to electrically interact with the anionic micelles of the crosslinked acrylic resin emulsion and nanocomposite emulsion, that is, they do not aggregate during manufacture or storage. By controlling the pH of the entire composition using a volatile base in this way, the water-based coating material composition for base preparation of the present invention has good storage stability.

On the other hand, when a coating film is formed, the volatile base volatilizes, the cationic functional groups of the water-soluble cationic polymer are exposed, and quick-drying is exhibited by the mechanism described above, promoting coating film formation. The Rukoto.

In addition, one of the major characteristics of the water-based coating material composition for base preparation of the present invention is that it has both water vapor permeability and water impermeability, and this is due to the use of a crosslinked acrylic resin emulsion and a nanocomposite emulsion. do. The crosslinkable acrylic resin emulsion increases the crosslink density of the resin, forms a dense coating film, and provides water impermeability. On the other hand, the nano-sized silica particles contained in the nanocomposite emulsion are dispersed in the coating film but do not chemically bond with the acrylic resin, so there are very fine gaps around them, and the gaps are continuous. It is presumed that the pore structure of a size that cannot be confirmed by the naked eye is formed in the coating film by connecting to the target, and the porous coating film is made to allow water vapor to permeate.

The inventors discovered that water vapor permeability can be imparted by mixing nano-sized silica particles into a conventional acrylic resin emulsion. However, simply adding the silica particles to an existing acrylic resin emulsion makes it difficult for the silica particles to appear on the surface of the coating film, and it is difficult to uniformly disperse the silica particles throughout the coating film. The water vapor permeability was not stable depending on the degree of dispersion. On the other hand, although attempts were made to stabilize the water vapor permeability by increasing the amount of the silica particles, there was a problem that the water impermeability and the strength of the coating film were lowered. By repeating trial and error and experiments, the inventor found that by using an appropriate amount of a nanocomposite emulsion containing nano-sized silica particles in acrylic resin in advance, the nano-sized silica particles are uniformly dispersed throughout the coating film and the coating surface is improved. It was found that it also appeared in the water vapor permeability, and finally, a formulation was reached in which an excellent balance between water vapor permeability and water impermeability was obtained.

In addition, the pore structure formed by nano-sized silica particles is formed not only in the thickness direction of the coating film but also in the continuous direction of the coating film, and water vapor permeates in the thickness direction and the continuous direction of the coating film. be able to. As shown in the following evaluation, the coating material finish structure formed by coating the water-based coating material composition for base preparation of the present invention with a top coating material having no water vapor permeability was evaluated to be resistant to blistering. It is inferred from the fact that no blistering or peeling occurs in the coating material finish structure even when subjected to the test of . For this reason, even if a topcoat material that does not have water vapor permeability is applied on the water-based coating material composition for base preparation of the present invention, the water vapor pressure related to the moisture contained in the base may cause Moisture is continuously supplied to the substrate, and the moisture accumulates at the interface with the coating film, making it possible to form a coating material finish structure that does not cause blistering or peeling because the moisture cannot escape as water vapor. Of course, in order to further improve the performance of the coating material finish structure, it is preferable to form the coating material finish structure by applying a top coat material having water vapor permeability by increasing the aggregate content, for example.

Various topcoat materials can be used regardless of whether they are permeable to water vapor or not, as described above, as the topcoat material for forming the coating material finish structure of the present invention. As a commercially available topcoat material with water vapor permeability, Jolypat Fresh JQ-800 (acrylic resin emulsion paint, resin content: 10 to 20 parts by weight, aggregate and filler: 40 to 60 parts by weight, Aica Kogyo Co., Ltd. company's product name), and as a non-water vapor permeable one, Jolypat Top Silicone JC-870 (acrylic silicone resin emulsion paint, resin content: 60 to 70 parts by weight, pigment: 10 to 20 parts by weight part, manufactured by Aica Kogyo Co., Ltd., trade name) and Aika Rino Paint Silicone JCS-H1 (2-liquid weak solvent silicone paint, resin content: 50 to 60 parts by weight, pigment: 10 to 20 parts by weight, manufactured by Aica Kogyo Co., Ltd., (trade name), etc., and can be used to form the coating material finish structure of the present invention.

Examples and comparative examples will be described below in detail.

<Examples and Comparative Examples>
In accordance with the formulations shown in Tables 1 and 2, base preparation water-based coating compositions of Examples and Comparative Examples were prepared. In Tables 1 and 2, Acronal YJ2741D (solid content: 56%, glass transition temperature of resin: −14° C., copolymer of acrylic and styrene, 0.1 carbonyl hydrazide as a cross-linking agent) is used as a cross-linkable acrylic resin emulsion. ~ 1.0 wt% content, manufactured by BASF, trade name), Primal EC-1791 (solid content: 55%, resin glass transition temperature: -40 ° C., acrylic resin emulsion) as a non-crosslinked acrylic resin emulsion 9 1200 as a nanocomposite emulsion (solid content: 40%, silica content: 15%, primary particle size of silica particles: 15 to 30 nm, average micelle Particle size: 90 nm, glass transition temperature of resin: 2 ° C., acrylic copolymer, manufactured by BASF, trade name), and lupasol FG (polyethyleneimine, solid content: 99%, weight) as a water-soluble cationized polymer. Average molecular weight (Mw): 800, manufactured by BASF, trade name), 25% aqueous ammonia solution (boiling point: 37.7°C) as a volatile base, and heavy calcium carbonate WA (average grain size) as a filler. Diameter D ₅₀ : 10 μm, manufactured by Shiraishi Calcium Co., Ltd., trade name), Nopal 700N (weight average molecular weight (Mw): 25,600, manufactured by San Nopco Co., Ltd., trade name) as an organic thickener A, SN Thickener 665T (weight average molecular weight (Mw): 19,800, manufactured by San Nopco Co., Ltd., trade name) was used as the organic thickener B, and Texanol CS-12 (manufactured by Chisso Co., Ltd., (trade name), ethylene glycol monoethyl ether acetate (manufactured by OXITENO Co., Ltd.) is used as film formation aid B, titanium oxide R-820 (trade name, manufactured by Ishihara Sangyo Co., Ltd.) is used as pigment, and other additives are used. Defoamers, dispersants, preservatives, and antifreeze agents selected from commercially available additives used in water-based compositions were added. The blending amount was adjusted so that the sum of the solid content of the crosslinked acrylic resin emulsion or the solid content of the non-crosslinked acrylic resin emulsion and the solid content of the nanocomposite emulsion in each example and comparative example was equal. bottom. Tables 1 and 2 show the weight ratio of the solid content of the crosslinked acrylic resin emulsion or the non-crosslinked acrylic resin emulsion to the solid content of the nanocomposite emulsion, and the pH of the composition.

<Production method>
Regarding the method for producing the water-based coating material composition for base preparation of Examples and Comparative Examples, first, a crosslinked acrylic resin emulsion or a non-crosslinked acrylic resin emulsion, a nanocomposite emulsion, a filler, and a composition are poured into a specific container. A film auxiliary agent, a pigment, and other additives were weighed out and mixed for about 5 minutes to homogenize them. Then, a volatile base was added and mixed for about 1 minute to disperse them uniformly. Next, an organic thickener is added and mixed, and a water-soluble cationized polymer is added and mixed for about 5 minutes to uniformly disperse, thereby preparing the base preparation water-based coating compositions of Examples and Comparative Examples. made. Finally, the pH of the composition was measured using a pH meter. The prepared water-based coating material composition for base preparation was transferred to a sealed container to prevent volatilization of the volatile base, and stored under an environment of 23° C. and 50% RH until evaluation.

<Evaluation method for base preparation water-based coating composition>
The water-based coating compositions for base preparation of the above examples and comparative examples were evaluated as follows. Unless otherwise specified, the preparation, curing, and evaluation test of test specimens were conducted in an environment of 23° C. and 50% RH.

<Quick-drying/hardening>
The water-based coating material composition for base preparation of Example or Comparative Example was applied to a glass plate using a roller brush at a coating amount of 0.4 kg/m ² , and visually and by touch after 1.5 hours. Observe the drying condition. ◯ indicates that the coating is dried and forms a smooth coating without whitening, and △ indicates that only the surface is dry and the inside of the coating is uncured (so-called skin burrs). Those with poor curing were evaluated as x.

Tests were also conducted at 35°C, 5°C and -5°C in the same manner as above and evaluated in the same manner.

<Coating workability>
A ceramic siding defined by JIS A5422, which is set vertically and horizontally, is used as a base, and the water-based coating material composition for base preparation of Examples and Comparative Examples is applied with a roller brush at a coating amount of 0.4 kg / m ² . and confirmed the coating workability. ○ indicates that there is no dripping and no rebound when applied. In addition, when the rebound was severe, or when the composition hardened during the application work and could not be applied, it was evaluated as x. The rebound means that the composition scatters around or to the operator when a roller brush is rolled for application.

At 35°C, 5°C, and -5°C, the coating workability was confirmed and evaluated in the same manner as described above.

<Viscosity/TI value>
For the water-based coating material compositions for base preparation of Examples and Comparative Examples, a BH type viscometer TVB-10 (manufactured by Toki Sangyo Co., Ltd., trade name) was used to measure the viscosity at a rotation speed of 2 rpm and the viscosity at a rotation speed of 20 rpm. It was measured. The TI value (thixotropic index) was determined according to JISA 6024 by dividing the viscosity at 2 rpm by the viscosity at 20 rpm. Those with a viscosity of 60 to 150 Pa s at 2 rpm were evaluated as ◯, and those with other values were evaluated as x.

<Elongation properties>
The water-based coating material compositions for base preparation of Examples and Comparative Examples were applied to a thickness of 0.5 mm with a roller brush and cured for 1 hour to dry. It was applied to a thickness of 0.5 mm to give a total thickness of 1.0 mm, cured for 1 week to prepare a sheet of the coating film, and punched out into a dumbbell-shaped No. 3 shape specified in JISK 6251 to obtain a test specimen. The specimen was subjected to a tensile performance test specified in JIS A 6021, and the elongation at break was measured. .

<Water vapor permeability>
On one side of a circular filter paper (diameter 150 mm, thickness 0.2 mm, Whatman, grade 41), the water-based coating material composition for base preparation of Examples and Comparative Examples was applied with a roller brush at a coating amount of 0.4 kg / m ² . After coating with and drying for 1 hour, the same water-based coating material composition for base preparation was applied with a roller brush at a coating amount of 0.4 kg / m ² and cured for 1 week. and Pour 400 mL of water into a cylindrical aluminum alloy cup with a height of 75 mm and a diameter of 140 mm. In order to prevent this, the ends of the specimen were sealed and allowed to stand for 3 days. After standing still, the weight of the entire container was measured, and the value was taken as the value before the test. Moisture permeability (g/day) is the value obtained by dividing the weight loss of the entire container before and after the test by the number of test days. A sample having a water vapor permeability of less than 0.6 was evaluated as having insufficient water vapor permeability and was rated as having a poor water vapor permeability.

<Water barrier>
For a flexible board (400 × 200 mm, thickness 4 mm) specified in JIS A 5430, apply the water-based coating material composition for base preparation of Examples and Comparative Examples to a coating amount of 0.4 kg / m ² with a roller brush. After applying it to the surface and drying it for 1 hour, the same water-based coating composition for base preparation was applied with a roller brush so that the coating amount was 0.4 kg / m ² and cured for 14 days. and used as a test specimen. Using the prepared specimen, the water permeability of the water permeability test B method of JIS A6909 was measured. In the test method, those with a water permeability of 0.5 mL or less were evaluated as having water impermeability, and those with a water permeability of more than 0.5 mL were evaluated as having no water impermeability, and were evaluated as x.

<Swelling resistance>
A test specimen was prepared by a method conforming to JIS A 6909 and tested. JISR 5201 specified mortar (70 × 70 mm, thickness 20 mm) was coated with a water-based coating material composition for base preparation of Examples or Comparative Examples at a coating amount of 0.4 kg / m ² with a roller brush, and was left for 1 hour. After curing and drying, the same water-based coating material composition for base preparation was applied with a roller brush at a coating amount of 0.4 kg/m ² and dried. After that, the four sides of the mortar were waterproofed with putty-like epoxy resin, and cured for 14 days to obtain a test specimen. The specimen was subjected to 10 cycles of "immersion in water at 23° C. for 18 hours→−20° C. for 3 hours→50° C. for 3 hours" for 10 cycles, and the presence or absence of swelling on the surface of the coating film was visually observed. A case where no swelling occurred was evaluated as ◯, a case where small swelling occurred was evaluated as Δ, and other cases were evaluated as x.

<Storage stability>
The viscosity of the water-based coating material composition for base preparation of Examples and Comparative Examples was measured with a BH type viscometer TVB-10 (trade name, manufactured by Toki Sangyo Co., Ltd.), and placed in a sealed container with a capacity of 500 mL under a 50 ° C. atmosphere. After standing still for 60 days, the viscosity was measured again, and the viscosities before and after the test were compared. Moreover, the appearance was visually observed. 〇 for those without significant viscosity change, composition separation, and aggregation, △ for those with slight viscosity change or small aggregates, and significant viscosity change, composition separation, and aggregation Those with any abnormality were evaluated as x.

At 5° C., the samples were allowed to stand for 60 days in the same manner as above, and the viscosities before and after the test were compared and the appearance was observed, and evaluated in the same manner.

<Evaluation results of base preparation water-based coating composition>
Tables 3 and 4 show the evaluation results of the base preparation water-based coating composition. Those that could not be evaluated due to agglomeration, hardening, etc. of the composition are indicated with "-".

<Evaluation of coating material finish structure>
Table 5 shows the composition of the coating material finishing structure and the evaluation results thereof. As shown in Table 5, Examples 2, 3, Comparative Example 3, and Comparative Example 4 were used as water-based coating compositions for base preparation, and topcoats having water vapor permeability were used as topcoats. Jolypat Fresh JQ-800 (acrylic resin emulsion paint, resin content: 10 to 20% by weight, aggregate and filler: 40 to 60% by weight, manufactured by Aica Kogyo Co., Ltd., trade name) as topcoat material A, water vapor permeation Jolypat Top Silicone JC-870 (acrylic silicone resin emulsion paint, resin content: 60-70% by weight, pigment: 10-20% by weight, manufactured by Aica Kogyo Co., Ltd., trade name), which is a topcoat material that does not have properties. Using this material as Material B, coating material finish structures of Examples I to IV and Comparative Examples I to IV were formed and evaluated as follows. Unless otherwise specified, the preparation, curing, and evaluation test of test specimens were conducted in an environment of 23° C. and 50% RH.

<Water vapor permeability>
A circular filter paper (diameter 150 mm, thickness 0.2 mm, Whatman, grade 41) was applied to one side of the base preparation water-based coating composition of Examples and Comparative Examples in Table 5 in an amount of 0.4 kg/m ² . After applying with a roller brush and curing for 1 hour to dry, the same water-based coating material composition for base preparation is applied with a roller brush at an application amount of 0.4 kg / m ² and dried. A water-based coating material composition layer for base preparation was formed. On top of that, topcoat agent A is applied in an amount of 0.35 kg/m ² or topcoat material B is applied in an amount of 0.15 kg/m ² with a roller brush, dried for 5 hours or more, and then topcoat agent A is applied again. A coating amount of 0.35 kg/m ² or topcoat material B was applied with a roller brush at a coating amount of 0.15 kg/m ² , dried, and cured for 1 week to obtain a test specimen. Pour 400 mL of water into a cylindrical aluminum alloy cup with a height of 75 mm and a diameter of 140 mm. In order to prevent this, the ends of the specimen were sealed and allowed to stand for 3 days. After standing still, the weight of the entire container was measured, and the value was taken as the value before the test. Moisture permeability (g/day) is the value obtained by dividing the weight loss of the entire container before and after the test by the number of test days. and those with a value of less than 0.6 were evaluated as having insufficient water vapor permeability and were evaluated as x.

<Swelling resistance>
A test specimen was prepared by a method conforming to JIS A 6909 and tested. The base preparation water-based coating composition of Examples and Comparative Examples was applied to JISR 5201 mortar (70 × 70 × 20 mm) at a coating amount of 0.4 kg / m ² with a roller brush, and cured for 1 hour. After drying, the same water-based coating material composition for base preparation was applied with a roller brush at a coating amount of 0.4 kg/m ² and dried to form a water-based coating material composition layer for base preparation. On top of that, topcoat agent A is applied in an amount of 0.35 kg/m ² or topcoat material B is applied in an amount of 0.15 kg/m ² with a roller brush, dried for 5 hours or more, and then topcoat agent A is applied again. A coating amount of 0.35 kg/m ² or topcoat material B was applied with a coating amount of 0.15 kg/m ² with a roller brush and dried. After drying, the four sides of the mortar were waterproofed with a putty-like epoxy resin, and cured for 14 days to obtain a test specimen. The specimen was subjected to 10 cycles of "immersion in water at 23° C. for 18 hours→−20° C. for 3 hours→50° C. for 3 hours" for 10 cycles, and the state of the coating film surface was visually observed. A case where no swelling occurred was evaluated as ◯, a case where small swelling occurred was evaluated as Δ, and other cases were evaluated as x.

<Zero span tensile elongation>
A flexible board (100×100 mm, thickness 10 mm) specified in JISA 5430 is used as a substrate, and the edges of the two substrates are pressed against each other, and the back surface is temporarily fixed with a curing tape. After applying the water-based coating material composition for base preparation of Examples and Comparative Examples to the surface of the base with a roller brush at a coating amount of 0.4 kg / m ² and drying for 1 hour, the same base preparation was performed. The water-based coating material composition for industrial use was applied with a roller brush in an application amount of 0.4 kg/m ² and dried for 4 hours or longer to form a water-based coating material composition layer for base preparation. On top of that, topcoat agent A is applied in an amount of 0.35 kg/m ² or topcoat material B is applied in an amount of 0.15 kg/m ² with a roller brush, dried for 5 hours or more, and then topcoat agent A is applied again. A coating amount of 0.35 kg/m ² or topcoat material B was applied with a roller brush at a coating amount of 0.15 kg/m ² and cured for 14 days to obtain a test specimen. Peel off the temporary curing tape on the back of the specimen, pull both ends of the specimen at 2 mm / min with a universal testing machine (manufactured by Instron), and the distance when a pinhole occurs in the coating film at the thrust part is Those having a thickness of 0.5 mm or more were evaluated as ◯, and those having a thickness of less than 0.5 mm were evaluated as x.

Claims (7)

A micelle with a particle size of 60 to 120 nm formed by a crosslinked acrylic resin emulsion having a glass transition temperature of −20 to 10° C., an acrylic resin containing one or more silica particles having a primary particle size of 15 to 30 nm, and an emulsifier. is dispersed in water, a water-soluble cationic polymer, a volatile base having a boiling point of 100 ° C. or less, a filler, an organic thickener, a film formation aid, a pigment, A composition comprising
The weight ratio of the solid content of the crosslinked acrylic resin emulsion to the solid content of the nanocomposite emulsion is 4 to 15:1,
The silica particles are 10 to 20 parts by weight in 100 parts by weight of the nanocomposite emulsion,
The amount of the water-soluble cationized polymer is 0.2 to 1.2 parts by weight in 100 parts by weight of the entire composition,
the pH of the entire composition is 9.5 to 11.5;
A water-based coating material composition for preparing a base, characterized by: 2. The water-based coating material composition for base preparation according to claim 1, wherein the water-soluble cationic polymer is a polyalkyleneimine compound. 3. The method according to claim 1 or claim 2, wherein the volatile base comprises any one or a mixture of two or more of ammonia, C ₁ -C ₄ lower alkylamine, and dimethylaminomethanol. Water-based coating material composition for base preparation. 4. The base preparation water according to any one of claims 1 to 3, wherein the organic thickener is a urethane-modified polyether having a weight average molecular weight (Mw) of 10,000 to 35,000. system coating material composition. The viscosity of the composition is 60 to 150 Pa s / 23 ° C. at 2 rpm of the BH type viscometer, and the TI value of the composition obtained by dividing the viscosity at 2 rpm of the BH type viscometer by the viscosity at 20 rpm is 4 to 7. The base preparation water-based coating material composition according to any one of claims 1 to 4, wherein the composition is 7. A substrate characterized in that the water-based coating material composition for substrate preparation according to any one of claims 1 to 5 is applied to the substrate at least twice with a coating thickness of 0.15 to 0.5 mm. adjustment method. A base preparation water-based coating composition layer formed by applying the base preparation water-based coating composition according to any one of claims 1 to 5, and the base preparation water-based coating composition. and a topcoat material layer formed by applying the topcoat material at least once onto the material layer.