JP2002256221A - Aqueous primer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aqueous primer composition having excellent adhesivity to a ceramic siding board, having excellent adhesivity to various kinds of top coatings. SOLUTION: This aqueous primer composition is obtained by mixing a main agent composed of a self-emulsifiable cationic water dispersion containing a hydroxy group and an amino group with an epoxy group-containing organosilane as a curing agent in an amount to make the equivalent ratio (amino group/ epoxy group) of the amino group of the cationic water dispersion to the epoxy group of the organosilane of 0.5-2.0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based primer composition for renovating a ceramic siding board, and more particularly, to an aqueous two-pack primer composition having excellent adhesion to a siding board substrate and a topcoat and excellent water resistance. About things.

[0002]

2. Description of the Related Art Various ceramic siding boards have been used for building exterior walls. In recent years, there has been an increasing demand for renovation of these siding boards, that is, repainting. However, when repainting the siding board,
Adhesion between the topcoat used for repainting and the surface of the siding board may not be sufficient, that is, when the same type of topcoat is applied to a different siding board surface, one of the siding boards has good adhesion It has been found that they do not adhere sufficiently to the other siding board.

[0003] This is considered to be because the paint applied to the surface of the siding board is different from, for example, fluorine coating, inorganic coating, urethane coating, acrylic coating, etc., depending on the composition and use of the siding board. ing. Therefore, in the current siding board repainting work, first, a primer having good adhesion to the paint applied to the siding board surface is selected, and furthermore, this primer has sufficient adhesion to the top coat paint. After confirming that
It is inevitable to apply a top coat.

[0004] Such selection and confirmation work of the primer and the top coat is not desirable from the viewpoint of work efficiency, and in order to easily renovate the outer wall of the ceramic siding board, it is necessary to apply any surface coating to the siding board. There is a strong demand for a primer which has good adhesion to a top coat and has no selectivity to a top coat, that is, which has good adhesion to any top coat. Furthermore, as the primer composition has excellent water resistance, so that blisters and the like do not occur in the coating film after the application of the top coating material,
Durability is also required.

[0005] Therefore, based on such a requirement, a solvent-based primer having excellent adhesion to both the siding board base material and the top coat has been developed and is currently commercially available. However, from the viewpoints of toxicity, danger, odor, and the like to organic solvents, it is strongly desired to use an aqueous primer.

The present invention has been made based on such a demand, and an object of the present invention is to have excellent adhesion to various ceramic siding boards,
An object of the present invention is to provide a water-based primer composition having good adhesion to various top coatings.

Another object is to provide an aqueous primer composition having excellent water resistance and durability.

[0008]

That is, the present invention comprises a self-emulsifying cationic aqueous dispersion having a hydroxyl group and an amino group and an organosilane containing an epoxy group, wherein the amino group of the cationic aqueous dispersion is combined with the organosilane. The equivalent ratio of epoxy group of silane (amino group / epoxy group) is 0.5 to 2.0
Aqueous primer composition in the range of

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Aqueous primer composition] The aqueous primer composition of the present invention comprises a self-emulsifying cationic aqueous dispersion having a hydroxyl group and an amino group, and an epoxy group-containing organosilane as a curing agent. Is a two-pack primer composition obtained by adding

<Self-emulsifying Cationic Aqueous Dispersion> The self-emulsifying cationic aqueous dispersion in the present invention is a two-part type aqueous dispersion in which a polymer dispersoid is dispersed in a dispersion medium containing water as a main component. Functions as the main agent in the aqueous primer composition. This self-emulsifying cationic aqueous dispersion comprises an ethylenically unsaturated monomer (A), a hydroxyl group-containing ethylenically unsaturated monomer (B) copolymerizable with the monomer (A), and a copolymerized with the monomer (A). A possible amino group-containing ethylenically unsaturated monomer (C) is polymerized in a solvent using a radical polymerization initiator, and the resulting polymer solution is neutralized using a neutralizing agent, and phase-changed with water. Can be obtained.

Here, the ethylenically unsaturated monomer (A)
Examples include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n C1-C24 alkyl or cycloalkyl esters of (meth) acrylic acid, such as hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, hydroxy C3-C8 hydroxyalkyl esters of (meth) acrylic acid such as propyl (meth) acrylate, styrene, vinyltoluene, α-
Basic aromatic unsaturated monomers such as methylstyrene, N-vinylpyrrolidone and vinylpyridine, alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate, vinyl acetate, maleic acid, itaconic acid, crotonic acid, etc. No. These monomers may be used in combination of two or more kinds.

The hydroxyl group-containing ethylenically unsaturated monomer (B) is a monomer copolymerizable with the monomer (A), and specifically includes 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, Polyoxyalkylene glycol (meth) acrylates such as 4-hydroxybutyl acrylate and diethylene glycol (meth) acrylate (the alkylene group has 2 to 4 carbon atoms, and the added mole number of the alkylene oxide is 1 to 50); caprolactone Modified hydroxy (meth) acrylate (trade name: Plaxel FM, FA, manufactured by Daicel Chemical Industries, Ltd.), N-methylolacrylamide, and the like. Among these, 2-hydroxyethyl methacrylate and caprolactone-modified hydroxy methacrylate are preferred from the viewpoint of cost and reactivity. In addition, you may use these monomers in combination of 2 or more types.

The amino group-containing ethylenically unsaturated monomer (C) is also a monomer copolymerizable with the above monomer (A), and specifically, includes an amino group-containing (meth) acrylate such as dimethylaminoethyl (meth) acrylate. Acrylic acid ester, acrylamide, diacetone acrylamide,
N, N-dimethylaminopropylacrylamide, N,
Examples include N-dimethylacrylamide, acryloylmorpholine, N-isopropylacrylamide, N, N-diethylacrylamide, amino group-containing (meth) acrylamide such as diethylaminopropylacrylamide, and the like. Among these, dimethylaminoethyl methacrylate is preferred from the viewpoint of reactivity. In addition, these monomers can also be used in combination of two or more.

The solvent used for the polymerization is not particularly limited as long as it is capable of solution polymerization and can dissolve the monomers to be used and the obtained polymer. Boiling point is 100 ℃
The following are preferred. Specific examples include methyl ethyl ketone, ethyl acetate, acetone, isopropyl alcohol and the like. These may be used in combination of two or more.

The polymerization initiator is not particularly limited as long as it is capable of undergoing radical decomposition by heat or a reducing substance to cause addition polymerization to a monomer. For example,
Azobisisobutyronitrile, benzoyl peroxide, t-butyl perbenzoate, t-butyl hydroperoxide, di-t-butyl peroxide, cumene hydroperoxide and the like can be used alone or in combination of several kinds. . In order to adjust the molecular weight of the resin, a chain transfer agent such as octyl mercaptan or dodecyl mercaptan can be added.

The neutralizing agent used for neutralizing the obtained polymer is an inorganic acid and / or an organic acid. Specific examples of the inorganic acid include hydrochloric acid and nitric acid. Specific examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid,
And aliphatic saturated carboxylic acids such as lactic acid. The amount used depends on the concentration of the polymerizable unsaturated monomer used, but is usually 0.2 to 1.0 mol of the neutralizing agent per 1 mol of the amino group in the polymer (neutralization ratio: 20 to 100
%). Thus, the aqueous dispersion according to the present invention becomes a cationic aqueous dispersion by neutralizing the base of the amino group-containing ethylenically unsaturated monomer (C) with an acid. In addition,
If the amount of the neutralizing agent is insufficient, the polymer may precipitate and cannot be used as a dispersion, while if the amount of the neutralizing agent is excessive, the polymer itself dissolves, and Water-soluble resin.

Here, the amount of the solvent used in the polymerization is as follows:
It is generally 40 to 60% by weight based on the total weight of the monomers, solvent and polymerization initiator used. The amount of the solvent at the time of solvent removal is 5 to 30% by weight, more preferably 10 to 25% by weight based on the total weight of the obtained polymer, solvent and water.
% By weight. When the amount of the solvent used is less than the above range,
When a water-based dispersant is synthesized, the viscosity of the solution becomes high, and sufficient neutralization and phase conversion cannot be performed. On the other hand, if it exceeds the above range, an aqueous dispersant can be obtained, but it is not preferable because a large amount of solvent must be distilled off.

The amounts of the monomer (A), the hydroxyl group-containing ethylenically unsaturated monomer (B) and the amino group-containing ethylenically unsaturated monomer (C) are determined according to the T of the obtained polymer.
It is preferable to adjust g so as to be -10 to 30C.

The water-dispersible coating composition according to the present invention can be prepared by adding components usually added to water-based paints, such as thickeners, defoamers, pigments, dispersants, dyes, and preservatives. Good.

As a specific polymerization method for producing the self-emulsifying cationic aqueous dispersion of the present invention, an ethylenically unsaturated monomer (A) and a hydroxyl group-containing ethylenic acid are used in a solvent in the presence of a radical polymerization initiator. Unsaturated monomer (B),
Dropping method of dropping a mixture of a monomer and a hydrophilic ethylenically unsaturated monomer (C); a solvent, a radical polymerization initiator, and a bath for performing a radical polymerization of a mixture of the monomers (A), (B) and (C). A polymerization method (a method in which a monomer or the like is charged at a time and polymerized) is exemplified. From the viewpoint of safety and control of the molecular weight, the monomer dropping method is preferred.

The production of the aqueous dispersion is carried out by neutralizing the obtained polymer solution with a neutralizing agent and then inverting the phase with water.

<Epoxy group-containing organosilane>
The epoxy group-containing organosilane used as a curing agent in the aqueous primer composition of the present invention can be represented by the following formula (1). Y-SiR _(3-a) X _a (1) In the formula (1), Y represents an epoxy group-containing group, X represents a hydrolyzable group, and R represents an alkyl group, an aryl group or an aralkyl group. a is an integer of 1 to 3.

Specific examples of the epoxy group-containing organosilane include glycidoxymethyltrimethoxysilane, glycidoxymethyltriethoxysilane, β-glycidoxyethyltrimethoxysilane, β-glycidoxyethyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyl (methyl) dimethoxysilane, γ-glycidoxypropyl (dimethyl) methoxysilane, γ-glycidoxypropyl Examples thereof include (ethyl) dimethoxysilane, (3,4-epoxycyclohexyl) methyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and γ-glycidoxypolysiloxane. Among them, γ-glycidoxypropyltrimethoxysilane is preferred from the viewpoint of compatibility and reactivity.

<Equivalent Ratio> In the present invention, from the viewpoint of crosslinking efficiency, the equivalent ratio (amino group / epoxy group) of the amino group of the cationic aqueous dispersion to the epoxy group of the organosilane is calculated as follows.
It needs to be in the range of 0.5 to 2.0. A more preferred range is from 0.7 to 1.5, most preferably 1.0.

In the present invention, as described above,
The quantitative ratio between the cationic aqueous dispersion as the main agent and the epoxy group-containing organosilane as the curing agent is defined by the equivalent ratio of the amino group of the cationic aqueous dispersion to the epoxy group of the organosilane (amino group / epoxy group). Therefore, if the concentration of the amino group contained in the cationic aqueous dispersion or the concentration of the epoxy group contained in the organosilane changes, the blending ratio of the two also changes. However, in general, the compounding ratio of the cationic aqueous dispersion as the main agent and the epoxy group-containing organosilane as the curing agent is in the range of 1 to 20 parts by weight of the organosilane with respect to 100 parts by weight of the aqueous dispersion. It is.

[Ceramic Siding Board] The ceramic siding board to which the water-based primer composition of the present invention is applied includes a binder such as cement, a reinforcing material such as inorganic or organic fiber, and a pearlite, coloring material or the like. Raw materials made by mixing admixtures are molded into a plate, cured and cured, and are mainly used as exterior materials for buildings. Ceramic siding boards, depending on their composition,
Wood fiber reinforced cement board siding board, fiber reinforced cement board siding board, fiber reinforced cement
It is classified as calcium silicate board siding board. Also, on the siding board surface, fluorine coating,
Coatings and patterns such as inorganic coating, urethane coating, silicon coating, and acrylic coating are applied. The aqueous primer composition of the present invention has excellent adhesion to any of these siding board surfaces.

[Overcoat] The water-based primer composition of the present invention also has good adhesion to all overcoats used when retrofitting ceramic siding boards. Specific examples of such a topcoat paint include a solvent-based acrylic paint, a solvent-based urethane paint, a solvent-based silicone paint,
Examples include, but are not limited to, solvent-based fluorine paints, water-based acrylic paints, water-based urethane paints, water-based silicone paints, water-based fluorine paints, inorganic paints, and main elastic materials.

[Method of Applying Water-Based Primer Composition to Ceramic Siding Board] The method of applying the water-based primer composition to a ceramic siding board may be in accordance with a conventionally known method, and specifically, brush coating. A method of applying the aqueous primer composition to the siding board by measuring the application amount by spraying, spraying, roller coating, or the like. In addition, the application amount is generally 0.10 to
It is about 0.15 kg / m ² (wet). After application,
Cured at room temperature for 24 hours to promote reaction hardening.

[Method of Applying Topcoat] The method of applying the topcoat may be a conventionally known method. Specifically, the top coat is applied to the siding board, which has been coated with the water-based primer composition and cured, by a method such as brush coating, spraying, and roller coating. The application amount is
Generally, it is set to about 0.2 to 0.3 kg / m ² (wet).

[0030]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, these Examples specifically show the constitution and effects of the present invention, and do not limit the scope of the present invention. It is not limited.

(Synthesis of Self-Emulsifying Cationic Aqueous Dispersion) [Synthesis Example 1] 80.0 parts by weight of methyl ethyl ketone (MEK) was charged into a reaction vessel equipped with a stirrer, a thermometer, and a cooler. On the other hand, 40.0 parts by weight of methyl methacrylate (MMA), 40.0 parts by weight of n-butyl acrylate (n-BMA), 10.0 parts by weight of 2-hydroxyethyl methacrylate (2-HEMA) were added to the dropping tank.
1 dimethylaminoethyl methacrylate (DMA)
0.0 part by weight and 1.0 part by weight of t-butylperoxy-2-ethylhexanoate were charged and uniformly mixed. Next, the reaction tank was heated to 80 ° C., and the mixed solution in the dropping tank was dropped into the reaction tank over 5 hours to cause a reaction. After completion of the dropping, 20.0 parts by weight of MEK and t-
Butylperoxy-2-ethylhexanoate
Parts by weight were mixed, uniformly mixed, dropped into the reaction tank over 1 hour, and reacted at 80 ° C. for 6 hours.

Thereafter, 1.2 parts of acetic acid was added to the reaction tank to sufficiently neutralize the mixture, and then 248.3 parts by weight of pure water was added thereto while stirring at a high speed, followed by phase inversion to obtain an aqueous dispersion. Finally, the entire amount of MEK was distilled off from the aqueous dispersion. Further, 20.0 parts by weight of a film-forming aid (Kyowanol M) and a wetting agent (BYK-
348) was added in an amount of 1.1 parts by weight, and an antifoaming agent (Nopco 8034) was added in an amount of 0.4 part by weight.
Self-emulsifying cationic aqueous dispersion having a viscosity of 50 mPa · s / 25 ° C. and an average particle size of 150 nm and an appearance of milky white (base agent 1)
I got

[Synthesis Examples 2 to 5] A self-emulsifying cationic aqueous dispersion (main agents 2 to 5) was prepared in the same manner as in Synthesis Example 1 except that the monomers, neutralizers, and the like used had the compositions shown in Table 1. ) Was synthesized.

[0034]

[Table 1]

(Preparation of Aqueous Primer Composition) [Example 1] 100 parts by weight of base material 1 obtained in Synthesis Example 1
And γ-glycidoxypropyltrimethoxysilane as a curing agent (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.)
Was mixed so that the equivalent ratio of amino group / epoxy group was 1.0 to obtain an aqueous primer composition.

Example 2 An aqueous system was prepared in the same manner as in Example 1 except that the main agent 2 was used in place of the main agent 1 and mixed with a curing agent so that the equivalent ratio of amino group / epoxy group was 1.0. A primer composition was obtained.

Example 3 An aqueous system was prepared in the same manner as in Example 1 except that the main agent 3 was used in place of the main agent 1 and mixed with a curing agent so that the equivalent ratio of amino group / epoxy group was 1.0. A primer composition was obtained.

Example 4 The procedure of Example 1 was repeated except that γ-glycidoxypropyltriethoxysilane was used as a curing agent and the main agent 1 was mixed so that the equivalent ratio of amino groups / epoxy groups was 1.0. An aqueous primer composition was obtained in the same manner.

Example 5 An aqueous primer composition was obtained in the same manner as in Example 1 except that the amount of the curing agent was adjusted so that the equivalent ratio of amino group / epoxy group was 0.5.

Example 6 An aqueous primer composition was obtained in the same manner as in Example 1 except that the amount of the curing agent was adjusted so that the equivalent ratio of amino group / epoxy group was 2.0.

[Comparative Example 1] The procedure of Example 1 was repeated except that γ-aminopropyltrimethoxysilane was used as a curing agent, and the mixture was mixed with the main agent 1 such that the equivalent ratio of the amino group of the main agent to the amino group of the curing agent was 1.0. An aqueous primer composition was obtained in the same manner as in Example 1.

Comparative Example 2 An aqueous system was prepared in the same manner as in Example 1 except that the main agent 4 was used instead of the main agent 1 and mixed with a curing agent so that the equivalent ratio of carboxyl group / epoxy group was 1.0. A primer composition was obtained.

Comparative Example 3 An aqueous system was prepared in the same manner as in Example 1 except that the main agent 5 was used in place of the main agent 1 and mixed with a curing agent so that the equivalent ratio of amino group / epoxy group was 1.0. A primer composition was obtained.

Comparative Example 4 An aqueous primer composition was obtained in the same manner as in Example 1 except that no curing agent was added.

Comparative Example 5 An aqueous primer composition was obtained in the same manner as in Example 1, except that the amount of the curing agent was adjusted so that the equivalent ratio of amino group / epoxy group was 0.2.

[Evaluation of Aqueous Primer Composition] (Evaluation of Curability of Aqueous Primer Composition) The aqueous primer compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 5 were coated on a glass plate in an amount of 0. It was applied with a brush to 12 kg / m ² , cured at room temperature for one day, rubbed with ethyl acetate, and the cured state of each aqueous primer coating film was evaluated. Table 2 shows the evaluation results.

[0047]

[Table 2]

As can be seen from Table 2, the aqueous primer coatings of Examples 1 to 6 were not changed by the rubbing of ethyl acetate, whereas the aqueous primer coatings of Comparative Examples 1 to 4
Rubbing with ethyl acetate dissolved it.

(Evaluation of Adhesion of Water-Based Primer Composition to Siding Board Surface Coating) A water-based acrylic coating, a solvent-based urethane coating, a solvent-based fluorine coating, and a solvent-based inorganic coating were applied to the surface of the siding board. A test piece was prepared by applying the aqueous primer composition of Example 1 to a substrate with a brush so that the application amount was 0.12 kg / m ^2, and the adhesion of the aqueous primer composition to the siding board surface coating was confirmed. did. For comparison, a commercial product,
One-component cold crosslinking cationic primer (water-based), two-component reaction-curable epoxy primer (aqueous), microelastic surfacer (water-based) used as an intermediate coating material, one-component moisture-curing siding board repair primer ( Similarly, the adhesion to the siding board surface coated with a water-based acrylic coating, a solvent-based urethane coating, a solvent-based fluorine coating, and a solvent-based inorganic coating was also confirmed for the solvent-based coating. Table 3 shows the results.

The adhesion was evaluated by a base test (J
(Based on the cross-cut test method of IS K5400 8.5.2.)
Was evaluated. Specifically, the test piece to which the water-based primer was applied was cross-cut using a cutter guide with a gap of 4 mm (25 cross-cuts; 5 vertical divisions x 5 horizontal divisions).
Made a cut. Next, a cellophane tape was adhered so as to cover the entire 25 grids, and one end of the adhered cellophane tape was held and immediately peeled off in a direction perpendicular to the coating surface. The case where the coating film was not peeled at all was set to 25, and when the coating film was peeled, the adhesiveness was indicated by “25− (number of peeled grids)”. The measurement results were evaluated in three stages. ：: 24 to 25 Δ: 20 to 23 ×: 0 to 19

[0051]

[Table 3]

(Evaluation of Adhesion of Aqueous Primer Composition to Commercial Siding Board Surface) The coating amount was 0.12 kg / m ^{2 on the} commercial siding board surface.
Each of the aqueous primer compositions of Examples 1 to 6 and Comparative Examples 1 to 5 was applied with a brush and cured at room temperature for one day to obtain a test specimen. In addition, the following siding boards A to K were used as commercially available siding boards for evaluation. Siding board A: Panse (made by Asahi Glass), siding board B: Kesera (made by Asahi Glass), siding board C: pure stone (made by Asahi Glass), siding board D: foreign country (made by Asahi Glass), siding board E: Moen S18 (made by Nichiha) ), Siding board F: Mirano (Nichiha), siding board G: Excellard 25 (Nichiha), siding board H: Romano (Nichiha), siding board I: Honjo (Matsushita Electric Works), siding board J: Belmatie (Matsushita Electric Works), Siding Board K: Hicera Coat (Matsushita Electric Works).

The adhesion of the aqueous primer composition to the surface of each siding board was confirmed. Further, for comparison, the adhesion to a glass plate and a flexible plate was also confirmed. Table 4 shows the results. In addition, regarding the evaluation of the adhesion, according to the grid test method of JIS K5400 8.5.2, the adhesion state was evaluated at 0 points (the area of the defective portion: 65% or more of the area of the entire square) and at 2 points (the area of the defective portion). : 35-65% of the total square area), 4 points (defect area: 15-35% of the total square area), 6 points (defect area: 5-15% of the total square area), 8 points (defect area) Area: 5 of total square area
% Or less) and 10 points (without missing portions). Result 3
The evaluation was divided into stages. ○: 6, 8, 10 points △: 4 points ×: 0, 2 points

[0054]

[Table 4]

(Evaluation of Adhesion of Water-Based Primer Composition to Top Coating Material)
Examples 1 to 6 and Comparative Examples 1 to 5 so as to become kg / m ^2.
After applying each aqueous primer composition with a brush and curing at room temperature for one day, apply the following various top coatings by spraying at 0.3 kg / m ^{2 to} cure at room temperature for 2 weeks. Body. Solvent-based acrylic paint: Acrylic # 6000 (manufactured by Asia Kogyo Co., Ltd.) Solvent-based urethane paint: Urethane # 7000 (manufactured by Asia Co., Ltd.) Solvent-based silicone paint: Silicon # 3100 (manufactured by Asia Co., Ltd.) Solvent-based Fluorine paint: Frontup # 9000 (Asia Industry Co., Ltd.) Water-based acrylic paint: Neogloss G-80 (Asia Industry Co., Ltd.) Water-based urethane paint: Neogloss U-200 (Asia Industry Co., Ltd.) Water-based silicone paint : Neogross S-300 (manufactured by Asia Kogyo Co., Ltd.) Water-based fluorine paint: Neogross F-100 (manufactured by Asia Co., Ltd.) Inorganic paint: Neoceratop 730 (manufactured by Asia Kogyo Co., Ltd.
Elastic main material: Elastic Alton main material (made by Asia Industry Co., Ltd.)

The adhesion of the water-based primer composition to various overcoats was confirmed. Table 5 shows the results. In addition, about the evaluation of adhesiveness, JIS K5400 8.
According to the cross-cut test method of 5.2, the adhesion state was 0 point, 2 points,
The points were represented by 4, 6, 8, and 10 points. The results were evaluated in three stages. ○: 6, 8, 10 points △: 4 points ×: 0, 2 points

[0057]

[Table 5]

(Evaluation of Water Resistance of Aqueous Primer Composition) A coating amount of 0.12 was applied to each surface of the siding boards A to K.
Each of the water-based primer compositions of Examples 1 to 6 and Comparative Examples 4 and 5 was applied with a brush so as to become kg / m ^2, and after curing at room temperature for one day, an aqueous silicone paint (Neogross S- 300 (Asia Industry Co., Ltd.) was applied by spraying at 0.3 kg / m ² and cured at room temperature for 2 weeks to obtain a test specimen. The seal was used.
In the test method of water resistance, the surface state was visually observed after the test specimen was immersed in water at room temperature for 2 weeks, and the abnormality of the painted surface was evaluated. As the evaluation criteria, based on the size and area of the blisters, the "fluffing" criteria as shown in Table 6 by the Japan Paint Inspection Association Paint Testing Method Study Group were used. In addition, it was set to 10 when there was no "swelling". Table 7 shows the evaluation results.

[0059]

[Table 6]

[0060]

[Table 7]

(Evaluation of Wet Resistance to Cooling and Heating Repeatability of Aqueous Primer Composition) Examples 1 to 6 and Comparative Examples 4 and 5 were applied so that the amount of coating was 0.12 kg / m ^{2 on} each surface of the siding boards A to K. After applying each aqueous primer composition of No. 5 with a brush and curing at room temperature for one day, an aqueous silicon paint (Neogros S-300 (Asia Industry Co., Ltd.)) is applied as a top coat paint to 0.3 kg / m ² by spraying. The test pieces were applied as described above and cured at room temperature for 2 weeks.
Furthermore, the back and side surfaces of the test specimen were sealed using epoxy resin. The test method for repetition resistance to wet and cold heat was 18 at room temperature based on JIS K5400 9.4.
3 hours at low temperature (-20 ° C), 3 hours at high temperature (50 ° C)
The immersion condition of time was defined as one cycle, and the surface state of the test specimen after 10 cycles of this was visually observed to evaluate the abnormality of the painted surface. Table 8 shows the results.

[0062]

[Table 8]

[0063]

As described above, the water-based primer composition of the present invention has good adhesion to various ceramic siding boards and also has good adhesion to various top coatings. Therefore, by using the water-based primer composition of the present invention, repair work of the siding board can be easily performed, and the degree of freedom in selecting a topcoat paint for the ceramic siding board can be remarkably improved.

Further, since the primer composition of the present invention is excellent in water resistance and wet / cooling / heat repetition resistance, the siding board surface after renovation can be maintained for a long time. Furthermore, since the primer composition of the present invention is a water-based primer, it is very excellent in terms of environmental problems and safety for workers. As described above, the water-based primer composition of the present invention is an industrially useful composition.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Tabata 3-8-5-206 Minami, Kuki City, Saitama Prefecture (72) Inventor Yutaka Yuta 1-9-8 Kurihara, Kuki City, Saitama Prefecture F-term (reference) 4J038 CG141 DL052 GA03 GA06 GA07 GA08 GA09 KA03 MA08 MA10 NA04 NA12 PA13 PA14 PB05 PB06 PC03

Claims (1)

[Claims] A self-emulsifying cationic aqueous dispersion having a hydroxyl group and an amino group and an epoxy group-containing organosilane, wherein the equivalent ratio of the amino group of the cationic aqueous dispersion to the epoxy group of the organosilane (amino group / Epoxy group)
Is a range of 0.5 to 2.0.