JP3115399B2 - Aqueous primer for inorganic porous substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aqueous primer for an inorganic porous substrate having a water-absorbing microporous surface, and more particularly, to an inorganic primer excellent in water resistance, warm water resistance, frost damage resistance and substrate adhesion. The present invention relates to an aqueous primer for a porous substrate.

[0002]

2. Description of the Related Art Heretofore, relatively low-molecular-weight moisture-curable urethanes, solvent-type resins, and the like have been used as resins for use as primers for inorganic porous substrates. In both cases, the danger of fire and environmental pollution due to the use of organic solvents have become problems, and there has been a strong demand for water-based use. As an aqueous undercoat, those having a water-soluble resin or an aqueous resin dispersion as a main component have been variously studied, but those having a water-soluble resin as a main component have poor water resistance,
In addition, the aqueous resin dispersion has poor fluidity because the polymer is present in the form of particles and has a high molecular weight of generally 500,000 to 1,000,000. There are drawbacks such as insufficient material adhesion and the inability to obtain a smooth coating film.In order to improve these drawbacks, it is necessary to use a small particle size, so-called microemulsion, or to add a water-soluble resin. Attempted. However, in order to reduce the particle size of the polymer, it is necessary to use a large amount of an emulsifier, and if a large amount of an emulsifier is used, the water resistance of the film is reduced due to the effect of the emulsifier, which is not practical. .

There is also a method using an aqueous dispersion of an epoxy resin. However, this method is excellent in impregnating properties on a substrate, but requires two liquids because of the use of a curing agent. There are problems and restrictions on the time for overcoating, and there are many problems in practical use.Therefore, an aqueous undercoating agent that is easy to handle and excellent in water resistance, warm water resistance, frost damage resistance, substrate adhesion, and the like is desired. It is rare.

[0004]

SUMMARY OF THE INVENTION The present invention provides an aqueous primer for an inorganic porous substrate, which can provide a film having excellent water resistance, adhesion to a substrate, warm water resistance and frost damage resistance. It is assumed that.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems, and as a result, have found that a specific copolymer resin can be added to an aqueous medium by adding an alkali and / or organic solvent. As a result, the present inventors have found that an aqueous undercoating agent in which a part or the whole thereof is solubilized can achieve the object, and the present invention has been completed.

That is, the aqueous primer for an inorganic porous substrate according to the present invention comprises: (a) 2 to 20% by weight of an ethylenically unsaturated carboxylic acid, and (b) an acrylic acid or methacrylic acid having 1 carbon atom in an aqueous medium. 10 to 10% by weight of a monomer selected from the group consisting of alkyl esters, vinyl aromatic compounds, vinyl halides, saturated vinyl carboxylate esters, acrylonitrile, methacrylonitrile, ethylene and butadiene. 5% by weight or more of the copolymer resin obtained by copolymerization of a monomer mixture consisting of 0 to 40% by weight of the other monomer is added and solubilized by adding an alkali and / or organic solvent. It is characterized by having.

Among the raw material unsaturated monomers for preparing the copolymer resin of the present invention, (a) the ethylenically unsaturated carboxylic acid may be a monocarboxylic acid or a polycarboxylic acid. Preferably, it is a mono- or di-olefinically unsaturated carboxylic acid having 3 to 5 carbon atoms. Particularly, acrylic acid, methacrylic acid and itaconic acid are preferred. The amount of ethylenically unsaturated carboxylic acid is 2 to 20% by weight, preferably 5 to 10% by weight, based on the total monomer mixture.
It is. If the amount of the monomer is too small, alkali and / or
Alternatively, when the solubilization treatment is performed by adding an organic solvent, sufficient solubilization (solubilization) cannot be performed, and sufficient smoothness and adhesion of the film cannot be obtained. On the other hand, if the amount of the monomer is too large, the hydrophilicity of the copolymer resin becomes too high, and the water resistance of the film is reduced, so that the adhesion to the substrate as a primer is reduced.

The monomer (b) includes an alkyl ester of acrylic acid or methacrylic acid having 1 to 10 carbon atoms (for example, methyl, ethyl, isopropyl, n-propyl, n-butyl or acrylic acid or methacrylic acid). Esters such as isobutyl and t-butyl), vinyl aromatic compounds (eg, styrene), vinyl halides (eg, vinyl chloride, vinyl bromide, vinylidene chloride), saturated vinyl carboxylate (eg, vinyl acetate, vinyl propionate), Acrylonitrile, methacrylonitrile, ethylene, butadiene and the like can be mentioned. Particularly preferred monomers (b) are alkyl esters of acrylic acid or methacrylic acid having 1 to 8 carbon atoms and vinyl acetate. Two or more of these monomers (b) may be contained in the copolymer.

The amount of the monomer (b) is 40 to 98% by weight,
Preferably it is in the range of 70 to 94% by weight. When the amount of the monomer (b) is less than the above range, the water resistance tends to decrease, and when the amount of the monomer (b) exceeds the above range, the water solubility decreases and the The material adhesion is reduced.

Further, the monomer (c) is other than the above-mentioned monomers (a) and (b), and the amount of the monomer (c) is 0 to 40% by weight, preferably 0 to 40% by weight. -20% by weight, and this monomer (c) is not an essential component. As the monomer (c), a carbonyl group-containing unsaturated monomer having at least one ald group or keto group and one polymerizable unsaturated double bond in the molecule, for example, acrolein,
Diacetone acrylamide, formylstyrene, 4-
Vinyl alkyl ketones having 7 carbon atoms (for example, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, etc.), a general formula

[0011]

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(Wherein R ¹ is H or CH ₃ , R ² is H or an alkyl group having 1 to ³ carbon atoms, R ³ is an alkyl group having 1 to ³ carbon atoms, and R ⁴ is an alkyl group having 1 to 3 carbon atoms. Acryl (or methacryl) oxyalkyl propenal, diacetone acrylate, acetonyl acrylate, diacetone methacrylate,
Hydroxypropyl acrylate acetyl acetate,
Monoolefinically unsaturated carboxylic acid amides (such as acrylamide, methacrylic acid amide, and itaconic acid amide) such as butanediol-1,4-acrylate acetylacetate; N-alkyl and / or monoolefinically unsaturated carboxylic acid amides; Or N-alkylol derivatives (for example, N-methylacrylamide, N-isobutylacrylamide, N-methylolacrylamide,
-Methylol methacrylamide, N-ethoxymethyl acrylamide), monoolefinically unsaturated sulfonic acids (eg, vinyl sulfonic acid, methyl acrylamide propane sulfonic acid, etc.), hydroxyethyl acrylate, hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate and the like. . Two or more of these monomers (c) may be contained in the copolymer.

The copolymerization for producing a copolymer resin is carried out by solution polymerization or emulsion polymerization using the above monomer mixtures (a) to (c). The solvent used for the solution polymerization is not particularly limited, but a water-soluble or hydrophilic solvent is preferred from the viewpoint of miscibility with the produced copolymer resin and water. Specific examples thereof include monoalcohols having 1 to 4 carbon atoms, for example, methyl alcohol,
Ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol and t-butyl alcohol; ethylene glycol and derivatives thereof, such as ethylene glycol monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether; diethylene glycol and derivatives thereof; For example, diethylene glycol monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether; and 1,4-dioxane and water. One of these solvents may be used, or two or more of them may be appropriately used in combination. As the solvent, those having a boiling point of 200 ° C. or lower are generally preferred in terms of distillation after polymerization or drying speed.

The polymerization initiator for solution polymerization is preferably an oil-soluble polymerization initiator. Specific examples thereof include azo initiators such as azobisisobutyronitrile and azobisvaleronitrile; organic peroxide initiators such as benzoyl peroxide, lauroyl peroxide and t-butyl peroxide; and other peroxides. Inorganic peroxide-based initiators such as hydrogen and ammonium persulfate can also be used. One type of these initiators may be used alone, or two or more types may be appropriately used in combination. Further, a reducing agent such as Rongalit, L-ascorbic acid, or an organic amine may be used in combination with these initiators to be used as a redox initiator.

A copolymer resin can also be produced by emulsion polymerization. In the emulsion polymerization, a method in which an emulsifier is used to carry out polymerization with a water-soluble polymerization initiator, or a soap-free polymerization is used. A method of performing polymerization and the like are used. Examples of the emulsifier include various anionic, cationic, and nonionic emulsifiers, and further, a polymer emulsifier. A particularly preferred emulsifier is a carbonyl group-containing polymer emulsifier described in JP-A-64-48801, which is a publication of a patent application according to the present invention (partly).

The polymerization initiator used in the emulsion polymerization is preferably an inorganic peroxide such as potassium persulfate, ammonium persulfate or hydrogen peroxide. These inorganic peroxides include:
The above-mentioned reducing agents may be used in combination as a redox initiator. Various methods can be used as a method for supplying the monomer in the emulsion polymerization. For example, various methods such as a batch charging method, a monomer addition method, and an emulsion addition method can be used. Also, a seed polymerization method in which the composition of the monomer to be added is sequentially changed, or a power feed method
A polymerization method or the like can also be used. When such a method is used, the degree of solubilization can be adjusted by changing the copolymerization composition between the center and the outside of the produced copolymer resin particles.

In the emulsion polymerization, a chain transfer agent is preferably used. This is because the copolymer resin obtained by emulsion polymerization generally has a high molecular weight, so that when it is solubilized in water by adding an alkali and / or an organic solvent, it is difficult to sufficiently solubilize it. If an agent is used, the molecular weight of the produced copolymer resin can be reduced, and the above-mentioned solubilization becomes easy. Examples of the chain transfer agent include various mercaptans, α
-Methylstyrene, alkyl halides, alcohols and the like. The amount used is from 0.03 to 5% by weight based on all monomers.

The copolymer resin prepared by the solution polymerization or the emulsion polymerization described above is adjusted so that the solubilization ratio of the copolymer resin becomes 5% by weight or more by adding an alkali and / or an organic solvent. The solubilization treatment is performed, that is, the solubilization treatment (ie, addition of an alkali and / or organic solvent)
May be before the start of copolymerization for producing the copolymer resin, or at the time of the copolymerization. In any case, the “solubilization rate” described in the present specification refers to the solubilization rate measured by the following method.

A copolymer resin is prepared by solubilizing treatment under exactly the same conditions as those actually performed, and the obtained copolymer resin is diluted with water so that the nonvolatile content becomes 15% by weight. After that, the diluted solution was centrifuged at 1.8 × 10 ⁵ g.
When the amount of non-volatile components in the obtained supernatant is measured to be w parts by weight, and the amount of non-volatile components in the diluent used for centrifugation is measured to be W parts by weight. Means the solubilization rate represented by the following formula: Solubilization rate = w / W x 100 (% by weight)

Therefore, for example, when the copolymerization is carried out by adding an alkali and / or an organic solvent to the polymerization system before or during the polymerization for producing the copolymer resin, When the solubilization rate of the polymerization product containing the produced copolymer resin obtained by polymerization has already reached 5% by weight or more, addition of an alkali and / or organic solvent for the solubilization treatment is performed again. Need not be performed.

Examples of the alkali used for the solubilization treatment include inorganic water-soluble alkalis such as sodium hydroxide and potassium hydroxide; and inorganic salts dissolved in water and exhibiting alkalinity such as sodium hydrogen carbonate and pyrophosphate. Sodium and the like; and other examples include ammonia water and organic amines. As described above, the addition of the alkali
It is not always necessary after the formation of the copolymer, and in some cases, an alkali is added to (a) the ethylenically unsaturated carboxylic acid before the copolymerization to form a copolymer resin, and the mixture is neutralized. Copolymerization may be performed. Also,
Addition of the alkali in the case of solution polymerization may be performed in the presence of the solvent used for the copolymerization, or partially or completely by adding the alkali to the copolymer resin after distilling off the solvent in an aqueous solution. May be solubilized in water. The amount of the alkali used may be an amount that completely neutralizes the carboxyl group in the copolymer resin, or may be an amount that partially neutralizes the carboxyl group.

The organic solvent used in the solubilization treatment may be supplementarily added when water cannot be sufficiently solubilized by adding only an alkali, or may be solubilized by adding only an organic solvent. In addition, when the copolymer resin is produced by solution polymerization, and the organic solvent used as the polymerization solvent can serve as an organic solvent for solubilization as it is, especially when the organic solvent is added again. May not be required, and in some cases, an organic solvent different from the organic solvent used as the polymerization solvent may be added. As the organic solvent to be used, the same solvents as described above as the solvent used for the solution polymerization can be used. Particularly preferred organic solvents are texanol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether and their acetates, benzyl alcohol, butyl carbitol acetate, 2,2,2
4-trimethyl-1,3-pentanediol and the like.

In order to improve the water resistance of the copolymer resin, at least one ald group or at least one ald group in the molecule exemplified as the other monomer of the above (c) as a constituent monomer of the copolymer resin. Copolymerization is carried out using a carbonyl group-containing unsaturated monomer having a keto group and one polymerizable unsaturated double bond, and then a hydrazine derivative having at least two hydrazino groups in the molecule is added. It is effective.

The unsaturated monomer having a carbonyl group is preferably used in a proportion of 0.5 to 30% by weight, more preferably 1 to 20% by weight in the total monomer mixture. If the amount of the monomer is too small, the content of the aldehyde group or keto group in the copolymer resin is too small, and even if a hydrazine derivative is added, sufficient water resistance, improvement in solvent resistance, etc. can be expected. Absent. On the other hand, if the amount of the monomer is too large, the alkali resistance and the weather resistance of the coating tend to decrease.

The hydrazine having at least two hydrazino groups in the molecule includes, for example, 2 to 10 hydrazines.
In particular dicarboxylic dihydrazides having 4 to 6 carbon atoms (eg oxalic dihydrazide, malonic dihydrazide, succinic dihydrazide, glutaric dihydrazide,
Adipic dihydrazide, sebacic dihydrazide, maleic dihydrazide, fumaric dihydrazide, itaconic dihydrazide), aliphatic water-soluble dihydrazine having 2 to 4 carbon atoms (for example, ethylene-1,2-dihydrazine, propylene-1) , 3-dihydrazine, butylene-1,4-dihydrazine, etc.).

Further, a general formula:

[0027]

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Wherein X is a hydrogen atom or a carboxyl group, Y is a hydrogen atom or a methyl group, and A is each unit of acrylamide, methacrylamide, acrylate, methacrylate or maleic anhydride. , B are units of a monomer copolymerizable with acrylamide, methacrylamide, acrylate, methacrylate or maleic anhydride, and k, m and n are 2 mol% ≦ k ≦ A polymer represented by the following formula: 100 mol% 0 mol% ≦ (m + n) ≦ 98 mol% (k + m + n) = 100 mol%) can also be used as the hydrazine derivative. Such a polymer is described in detail, for example, in JP-A-55-6535.

The mixing ratio of the hydrazine derivative is such that the ratio of the carbonyl group to the hydrazino group contained in the copolymer resin and other additives (specifically, the aqueous resin dispersion described below) is
(> C = O) / ( - NHNH 2) is preferably in the molar ratio 0.2 to 5.0, more preferably the ratio becomes 0.3 to 2.0. If the proportion of the hydrazine derivative is too small,
Improvement of water resistance cannot be expected because the cross-linking between the resins is not sufficiently performed, and even if the ratio is too large, not only the water resistance improvement effect corresponding to that is not obtained, but also the film It is opaque and brittle.

In the present invention, another aqueous resin dispersion may be added for the purpose of improving the water resistance and alkali resistance of the film, or adjusting the viscosity, and the aqueous resin dispersion is obtained by synthesis. Aqueous emulsions of synthetic resins obtained or of a wide variety of natural resins are preferred, but synthetic resin emulsions obtained by emulsion polymerization are preferred. As generally known, an aqueous synthetic resin dispersion obtained by emulsion polymerization uses an emulsifier, a reactive emulsifier or a protective colloid as a dispersant, and uses a water-soluble initiator to convert an unsaturated monomer into water. It is obtained by (co) polymerization. As the unsaturated monomer, for example, acrylic acid,
For the purpose of methacrylic acid, their various esters, vinyl aromatic compounds such as styrene, vinyl halide, acrylonitrile, methacrylonitrile, saturated vinyl carboxylate, conjugated dienes, and unsaturated hydrocarbons such as ethylene and propylene. In general, an aqueous dispersion of a copolymer resin, which is appropriately used in combination, is suitably used.

In addition to the aqueous resin dispersion obtained by emulsion polymerization, there are, for example, polyurethane resin emulsions, alkyd resin emulsions, and bisphenol-type epoxy resin emulsions. These aqueous resin emulsions are also used as aqueous resin dispersions. Can be.

A particularly preferred aqueous resin dispersion is 0.5 to 20% by weight of the carbonyl group-containing unsaturated monomer exemplified as the component (c); the ethylenically unsaturated carboxylic acid exemplified as the component (a). 0 to 10% by weight of an acid; an alkyl ester of acrylic acid or methacrylic acid having 1 to 10 carbon atoms exemplified as the component (b), acrylonitrile, methacrylonitrile, a vinyl aromatic compound, vinyl halide, or a saturated carboxylic acid. By emulsion polymerization of a monomer mixture of 55 to 99.5% by weight of at least one unsaturated monomer selected from vinyl esters, ethylene and butadiene; and 0 to 15% by weight of other monomers. This is an aqueous dispersion of the obtained copolymer resin.

The carbonyl group-containing unsaturated monomer used in this case is the same as the carbonyl group-containing unsaturated monomer exemplified as the preferred component (c) in the case of the copolymer resin. A resin aqueous dispersion containing the unsaturated monomer as a constituent component, and a copolymer resin copolymerized using a carbonyl group-containing unsaturated monomer as a constituent unit of the copolymer resin to be solubilized. The aqueous undercoating agent of the present invention is a hydrazine derivative-mediated inter-copolymer resin, inter-copolymer resin constituting an aqueous resin dispersion, and cross-linking between both resins. Can be formed, so that the physical properties of the crosslinked film are further improved.

The mixing ratio of the copolymer resin and the aqueous resin dispersion in the present invention may be arbitrary, but is preferably from 10/0 to 2/8, more preferably from 10/0 to 2/8, by weight based on the solid content.
/ 0 to 3/7. If the proportion of the copolymer resin is too small, a film is formed on the surface layer of the substrate, and the effect of improving the adhesion, smoothness, and gloss of the film to the substrate tends to be insufficient.

The method of mixing the copolymer resin and the aqueous resin dispersion is not particularly limited. For example, after adding an alkali solution to an organic solvent solution containing a copolymer resin obtained by solution polymerization, the solvent is distilled off, and then the aqueous resin dispersion may be added, or the solvent may be distilled off. It may be added without. When the copolymer resin is obtained by emulsion polymerization, an alkali and / or organic solvent may be added to an aqueous dispersion of the copolymer resin to solubilize the resin, and then the aqueous resin dispersion may be added. . Further, an alkali and / or organic solvent may be added after mixing the copolymer resin and the aqueous resin dispersion.

In the present invention, when the aqueous resin dispersion or the hydrazine derivative is added, the solubilization treatment of the copolymer resin prepared by solution polymerization or emulsion polymerization is performed by adding the aqueous resin dispersion and the aqueous resin dispersion to the copolymer resin. It may be before mixing the hydrazine derivative, during the mixing, or after the mixing.

Further, in the present invention, in a system using a copolymer resin obtained by polymerization using a carbonyl group-containing unsaturated monomer as the component (c) and a hydrazine derivative, a reaction between a carbonyl group and a hydrazino group is performed. Proceeds with drying and film formation, but is slightly carried out even in the aqueous phase, so that gelation is likely to occur. To prevent this, it is preferable to add a low molecular compound (aldehydes or ketones) containing a carbonyl group based on an ald group or a keto group and having a boiling point of 200 ° C. or lower. Its boiling point is preferably 120 ° C. or lower, more preferably 100 ° C. or lower.

This is because under the condition where a large amount of water is present, such as a film during storage of the aqueous primer of the present invention or before drying,
The compounded low molecular weight aldehydes and ketones react with the hydrazino group of the hydrazine derivative to block the hydrazino group, so that the cross-linking reaction between the polymers is effectively prevented and the gelation of the resin is stopped. It is considered that the gelation time can be extended.

Specific examples of the aldehydes or ketones include, for example, formaldehyde (boiling point −21 ° C.),
β-hydroxyethyl methyl ketone (182 ° C), acetaldehyde (21 ° C), propionaldehyde (49 ° C), butyraldehyde (75 ° C), valeraldehyde (103 ° C), isovaleraldehyde (93 ° C) ), Pivalinaldehyde (75 ° C), capronaldehyde (131 ° C), heptaldehyde (15 ° C)
3 ° C), glyoxal (51 ° C), succindialdehyde (170 ° C), acrolein (52 ° C), propioaldehyde (60 ° C), crotonaldehyde (105 ° C), acetone (56 ° C) , Ethyl methyl ketone (80 ° C), methyl propyl ketone (10
2 ° C.), isopropyl methyl ketone (95 ° C.), butyl methyl ketone (127 ° C.), isobutyl methyl ketone (117 ° C.), pinacolone (106 ° C.), diethyl ketone (102 ° C.), butyrone (144 ° C.) ° C), diisopropyl ketone (124 ° C), methyl vinyl ketone (81 ° C), acetoin (148 ° C) and the like. One type of these aldehydes or ketones may be used, or two or more types may be used in combination.

The aqueous primer of the present invention may contain film-forming auxiliaries, pigments, fillers, wetting agents and the like.

[0041]

The present invention will be described in detail with reference to examples of preparing a copolymer resin, examples of preparing an aqueous resin dispersion, examples and comparative examples. "Parts" and "%" described in these examples are based on weight. Preparation Example 1 of Copolymer Resin Temperature Controller, Ikari Type Stirrer, Reflux Cooler, Supply Container,
After the inside of a reaction vessel equipped with a thermometer and a nitrogen inlet tube was purged with nitrogen, 130 parts of ethylene glycol monobutyl ether was charged therein.

Separately, the following compositions were prepared as feeds. Feed Ethylene glycol monobutyl ether 110 parts Acrylic acid 5 parts Diacetone acrylamide 5 parts 2-hydroxyethyl acrylate 5 parts Butyl acrylate 25 parts Methyl methacrylate 60 parts Benzoyl peroxide 3 parts Next, the inside of the reaction vessel is kept at 80 ° C. Meanwhile, the above-mentioned feed was continuously supplied little by little over 3 hours.
After the completion of the supply, the temperature was maintained for another 2 hours to complete the polymerization.

This solution was concentrated by distillation until the nonvolatile content became 60%, and 23 g of a 10% aqueous sodium hydroxide solution was added to obtain an ethylene glycol monobutyl ether solution of a copolymer resin having a nonvolatile content of 54%. Next, 30 parts of a mixture of ethylene glycol monobutyl ether and water was distilled off from the obtained solution using a rotary evaporator, and then water was added thereto, and a nonvolatile portion of 20%, p
An H9 copolymer resin solution was obtained.

Copolymer Resin Preparation Examples 2 and 3 The procedure was the same as in Preparation Example 1, except that the monomer composition of the feed and the polymerization solvent were changed as shown in Table 1.

Preparation Example 4 of Copolymer Resin The same reaction vessel as used in Preparation Example 1 was charged with the following. Water 50 parts 35% aqueous solution of sulfuric acid half ester sodium salt of ethylene oxide 20 mol added p-nonylphenol (referred to as “anionic emulsifier A”) 2 parts ethylene oxide 25 mol added p-nonylphenol (referred to as “nonionic emulsifier B”) Separately, the following mixture was prepared as Feed I separately.

Feed I Water 50 parts 35% aqueous solution of anionic emulsifier A above 4 parts 20% aqueous solution of above nonionic emulsifier B 2 parts Methyl methacrylate 55 parts Butyl acrylate 30 parts Diacetone acrylamide 5 parts Acrylic 5 parts of acid 5 parts of methacrylic acid 0.7 part of t-dodecyl mercaptan 0.7 part Separately, an aqueous solution prepared by dissolving 0.7 part of potassium persulfate in 20 parts of water was provided as a feed II.

After the inside of the reaction vessel was replaced with nitrogen gas, 10% of the feed I was added to the charge, and the mixture was heated to 90 ° C. Then, 10% of Feed II was injected into the reaction vessel, and then the remaining Feeds I and II were fed in small portions in parallel over 3.5 hours. After completion of the supply, the emulsion polymerization was completed by maintaining the temperature at 90 ° C. for 1.5 hours.

The aqueous resin dispersion thus obtained was diluted with water so that the nonvolatile content was 20%.
A 5% aqueous ammonia solution was added so that the pH became 9.

Copolymer Resin Preparation Examples 5 to 8 Copolymer resin preparation examples 5 to 8 were carried out in the same manner as in Preparation Example 4 except that the monomer composition of the feed and the chain transfer agent present in the polymerization system were changed as shown in Table 2.

Preparation Example 9 of Copolymer Resin The same reaction vessel as used in Preparation Example 1 was charged with the following. Water 50 parts Na lauryl sulfonate 2 parts 35% aqueous solution of anionic emulsifier A 3 parts Separately, the following mixture was prepared as Feed I.

Water 50 parts Na lauryl sulfonate 1 part 35% aqueous solution of anionic emulsifier A 2 parts Styrene 50 parts butyl acrylate 30 parts acrylic acid 5 parts methacrylic acid 5 parts diacetone acrylamide 10 parts t-dodecyl mercaptan 0. 5 parts Separately, as Feed II, an aqueous solution was prepared by dissolving 0.5 part of potassium persulfate in 20 parts of water.

After replacing the inside of the reaction vessel with nitrogen gas, 10% of the feed I was added to the charge, and the mixture was heated to 90 ° C. Then, 10% of Feed II was injected into the reaction vessel, and then the remaining Feeds I and II were fed in small portions in parallel over 3.5 hours. After the completion of the supply, the emulsion polymerization was maintained at 90 ° C. for 1.5 hours to complete the emulsion polymerization.

The aqueous resin dispersion thus obtained is diluted with water so that the nonvolatile content becomes 20%.
0% sodium hydroxide is added so that the pH becomes 9,
Further, 3 parts of ethylene glycol monobutyl ether was added.

Copolymer Resin Preparation Examples 10 to 12 Copolymer resin preparation examples 10 to 12 were carried out in the same manner as in Preparation Example 9 except that the monomer composition of the feed was changed as shown in Tables 2 and 3.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

[Table 3]

Preparation Example A of Aqueous Resin Aqueous Dispersion In the same reaction vessel as used in Preparation Example 1 above, the following was charged. Water 200 parts 35% aqueous solution of anionic emulsifier A 5 parts 20% aqueous solution of nonionic emulsifier B 20 parts Separately, the following mixture was prepared as Feed I.

Feed I Water 200 parts 35% aqueous solution of the above anionic emulsifier A 25 parts Acrylic acid 10 parts Diacetone acrylamide 23 parts Butyl acrylate 198 parts Styrene 235 parts Separately, as Feed II in 85 parts of water A solution in which 2.5 parts of potassium persulfate was dissolved was prepared.

After purging the reactor with nitrogen gas, 10% of feed I was added to the charge and the mixture was heated to 90 ° C. Then 10% of Feed II was injected into the reactor, and the remaining Feeds I and II were fed into the reactor in small, evenly parallel batches over a period of 3 to 3.5 hours. After the completion of the supply, the temperature was raised to 90 ° C., and the same temperature was further maintained for 1.5 hours to carry out emulsion polymerization. The resulting resin aqueous dispersion had a nonvolatile content of 47% and a minimum film-forming temperature of 20 ° C.

Resin Aqueous Dispersion Preparation Examples B and C Emulsification was carried out in the same manner as in Preparation Example A, except that the monomer composition of Feed I in Preparation Example A was changed as shown in Table 4. Polymerization was performed to obtain an aqueous dispersion of a copolymer resin.

[0062]

[Table 4]

Example 1 70 parts of a 20% nonvolatile ethylene glycol monobutyl ether solution obtained in Copolymer Resin Preparation Example 1, 70 parts of copolymer resin aqueous dispersion obtained in Resin Aqueous Dispersion Preparation A 3
0 parts and a 20% aqueous solution of adipic dihydrazide 20
Parts were mixed. The resulting dried film of the aqueous primer was tested for adhesion, uneven coating, water resistance, warm water resistance, and frost resistance according to the following test methods.
Was as shown in FIG.

As a test piece, a calcium silicate plate having a size of 5 cm × 10 cm, which was applied so that the coating amount after drying was 20 g / m ^2, and dried at 100 ° C. for 10 minutes to form a film was used.

Adhesion: The test piece was cut into 5 × 5 grids at 3 mm intervals with a cutter knife, and an adhesive tape made of polyester was pressed and then peeled off to check the remaining state of the coating film. ◎: The coating film was not peeled at all. ：: The coating film was slightly peeled. Δ: The coating film was partially peeled. ×: The coating film was entirely peeled.

Top coat unevenness: A paint obtained by mixing the following as a top coat paint on a test piece was applied so that the film thickness after drying was 50 μm, and dried at 100 ° C. for 10 minutes to form a film. The appearance was visually evaluated.

Topcoat coating composition water 64.6 parts Demol EP (manufactured by Kao Corporation) 20 parts Nopco 8034 (manufactured by San Nopco) 0.3 parts titanium oxide (rutile type) 54.0 parts kaolin 6.0 parts Acronal YJ- 2770D (Mitsubishi Yuka Birdish) 146.7 parts Texanol (Eastman Kodak) 9.5 parts 5% -Adecanol UH-420 (Asahi Denka) 1.0 part

◎: no unevenness ○: slight unevenness Δ: unevenness X: lifting

Water resistance: The test piece was immersed in water at 20 ° C. for 5 days, dried at room temperature for 2 days, and evaluated in the same manner as the evaluation of adhesion.

Warm water resistance: The test piece was immersed in warm water of 40 ° C. for 5 days, dried at room temperature for 2 days, and examined for adhesion by the same method as described above.

Freezing damage resistance: immersion in water at 10 ° C. for 2 hours → −2
After 200 cycles of 2 cycles of freezing in air at 0 ° C. for 2 hours, and drying at room temperature for 2 days, the adhesion was examined in the same manner as described above.

Examples 2 to 13 and Comparative Examples 1 to 4 The types and amounts of the copolymer resin, the aqueous resin dispersion and the hydrazine derivative were changed as shown in Tables 5 to 8, and An aqueous primer was prepared in the same manner as in Example 1 except that butyl ether was blended in the respective amounts, and the physical properties of the film were tested in the same manner.

Tables 5 to 8 show the composition ratios (parts) and the like of the aqueous primers obtained in each of the examples and comparative examples, and the test results of the film properties.

[0074]

[Table 5]

[0075]

[Table 6]

[0076]

[Table 7]

[0077]

[Table 8]

Notes to Tables 5 to 8 * 1 ... adipic dihydrazide * 2 ... maleic dihydrazide As is clear from Tables 5 to 8, the primers of the Examples were compared with those of Comparative Examples. Excellent in terms of adhesion, non-uniform coating, water resistance, warm water resistance and frost damage resistance.

[0079]

The aqueous primer of the present invention is excellent in water resistance, warm water resistance, adhesion to a substrate, and frost damage resistance, and can provide an excellent film which does not cause unevenness in a top coat.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C09D 133/06 C09D 133/06 133/18 133/18 147/00 147/00 (72) Inventor Yoshinori Kato Kawajiri, Yokkaichi, Mie Prefecture No. 1000, Mitsubishi Yuka Birdishe Co., Ltd. (72) Inventor Ryutaro Hayashi 1000, Kawajiri-cho, Yokkaichi, Mie Prefecture Inside Mitsubishi Yuka Birdishe Co., Ltd. (56) References JP-A-3-68669 (JP, A) JP 64-40574 (JP, A) JP-A-11-217559 (JP, A) JP-A-11-124517 (JP, A) JP-A-6-190332 (JP, A) (58) Fields studied (Int) .Cl. ⁷ , DB name) C09D 5/00 C09D 123/08 C09D 125/02 C09D 127/06 C09D 131/02 C09D 133/06 C09D 133/18 C09D 147/00 CA (STN) CAOLD (STN) REGISTRY ( STN)

Claims (3)

(57) [Claims] 1. An aqueous medium comprising: (a) 2 to 20% by weight of an ethylenically unsaturated carboxylic acid; (b) an alkyl ester of acrylic acid or methacrylic acid having 1 to 10 carbon atoms, a vinyl aromatic compound, and a halogenated compound. Monomer selected from the group consisting of vinyl, saturated vinyl carboxylate, acrylonitrile, methacrylonitrile, ethylene and butadiene 40 to 98% by weight (c) Monomer composed of 0 to 40% by weight of other monomers A copolymer resin obtained by copolymerization of a body mixture, wherein at least 5% by weight of the copolymer resin is solubilized by the addition of an alkali and / or an organic solvent, and is present. Primer. 2. The method according to claim 1, wherein the other monomer (c) in the monomer mixture contains at least one ald group or carbonyl group based on a keto group in the molecule and has one polymerizable double bond. A hydrazine derivative having a carbonyl group-containing unsaturated monomer having a bond of 0.5 to 30% by weight and having at least two hydrazino groups in the molecule; The aqueous primer for an inorganic porous substrate according to claim 1, wherein 3. The ratio of the ald group or keto group contained in the copolymer resin to the hydrazino group contained in the hydrazine derivative is 0.2 by (> C ＝ O) / (— NHNH ₂ ) molar ratio.
The aqueous primer for an inorganic porous substrate according to claim 2, which is from 5.0 to 5.0.