JP2528193B2 - Aqueous liquid for primer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an aqueous solution for a primer used for surface modification of a porous alkaline inorganic base material such as concrete and mortar.

[Conventional technology]

Cement-based inorganic building materials such as concrete, mortar, and slate boards have a weak surface layer, so a primer solution is applied to the surface for the purpose of reinforcing the surface and improving the adhesion and adhesion to the coating for surface finishing. Applying has occurred. As such a primer solution, a solvent type primer solution in which a synthetic resin is dissolved in an organic solvent has been conventionally used. However, since the solvent-type primer liquid is volatile, the solvent-type primer liquid has many problems in safety and hygiene such that it is easily ignited and has a bad influence on the human body by inhalation. Therefore, the present applicant has developed an aqueous solution for a primer using an organic solvent and using water as a medium, and has already applied for it (Japanese Patent Application No. 62-80694).

[Problems to be Solved by the Invention]

However, the above-mentioned aqueous solution for a primer undergoes a cross-linking reaction in an alkaline environment to form an excellent water-resistant film, and there is no problem when used for a general substrate having high alkalinity. However, base material with low alkalinity,
Alternatively, when it is applied to a neutral base material, a sufficiently durable film cannot be obtained, and therefore improvement thereof has been demanded.

The present invention has been made in view of the above circumstances and is excellent in base material permeability, base material reinforcing property, and the like, and is an aqueous primer liquid capable of forming a strong film regardless of the alkalinity of the base material. The purpose is to provide.

[Means for solving the problem]

In order to achieve the above object, the present invention provides the medium with the following component (A) in an amount of 5 to 99.5% by weight and the following component (B).
An aqueous solution for a primer containing a copolymer obtained by copolymerizing at a proportion of 0.5 to 95% by weight is defined as a first gist, and (A) a cationic alkali crosslink represented by the following general formula (I). Type monomer.

R: H or CH ₃ Y: Organic or inorganic monovalent anion n: integer of 1 to 3 (B) An alkoxysilane monomer represented by the following general formula (II).

R: H or CH ₃ Z: CH _{2 n} or Where n is 0 to 3 X: in -OCH ₃ or -OC ₂ H ₅ or -OC ₂ H ₄ OCH ₃ medium, the component (A) to 5% by weight or more, component (B) 0.5 wt% or more The second gist is an aqueous solution for a primer containing a copolymer obtained by copolymerizing an ethylenically unsaturated monomer at a ratio of 94.5% by weight or less,
A third aspect of the present invention is an aqueous primer liquid in which a polymer obtained by polymerizing an ethylenically unsaturated monomer is dispersed and contained in either of the above two types of aqueous primer liquids.

[Action]

That is, the present inventors have made a series of water-soluble resins, especially acrylic resins, in order to find an aqueous solution for a primer that can form a durable and strong film regardless of the type of base material (inorganic building material). Researched. As a result, when the special monomers (components A and B) represented by the general formulas (I) and (II) are copolymerized at a specific ratio, the chain polymer obtained is in water. It has been found that the aqueous solution shows good solubility and penetrates well into the surface layer of the substrate to form a film excellent in water resistance and alkali resistance. Further, it was also found that the coating film not only reinforces the surface of the base material with high strength, but also has excellent adhesiveness and adhesion to the coating film of the topcoat paint and the adhesive layer.

The reason why the film obtained from the aqueous liquid for a primer of the present invention has high strength as described above is considered to be as follows. That is, the polymer constituent component derived from the cationic alkali crosslinkable monomer (component A) represented by the general formula (I) of the present invention is activated by the alkali in the base material in an alkaline environment. Are crosslinked, and a cross-linking reaction occurs between the chain polymers to form a three-dimensional network structure film. Further, the polymer constituent component derived from the alkoxysilane monomer (component B) represented by the general formula (II) is hydrolyzed by the water present in the aqueous liquid, and this hydrolysis product is At the time of drying after the application of the aqueous solution, a crosslinking reaction occurs with the evaporation of water, and also a three-dimensional network structure film is formed. Therefore, the aqueous solution for a primer of the present invention, when used for a substrate close to neutrality, causes a crosslinking reaction due to the component derived from the above alkoxysilane monomer to form a film excellent in water resistance and alkali resistance. When used for a base material having high alkalinity, a synergistic effect of the crosslinking reaction by the component derived from the above cationic alkali crosslinking type monomer and the crosslinking reaction by the component derived from the alkoxysilane monomer is obtained. As a result, the crosslink density increases, forming a film with excellent water resistance and alkali resistance. Therefore, the base material surface is reinforced with high strength. Moreover, since this film has a cationic constitutional unit derived from the above-mentioned cationic alkali cross-linking monomer, the adhesiveness and adhesion with the top coating or adhesive etc. that can be applied on this film It also improves sex. The above two types of special monomers (A component, B component)
It was found that by co-polymerizing the above with an ethylenically unsaturated monomer, the adhesion and the adhesion to the finishing layer of the film are further improved. Further, the ethylenically unsaturated monomer is polymerized by emulsion polymerization or the like alone, and this is (A) +
It has been found that the same effect can be obtained by mixing with the copolymer-containing liquid of (B) or the copolymer-containing liquid of (A) + (B) + ethylenically unsaturated monomer.

 Next, the present invention will be described in detail.

Water is the most suitable medium for use in the present invention. However, water may be used in combination with an easily soluble organic solvent for the purpose of increasing the solubility of the cation-alkali crosslinkable monomer to be copolymerized or the permeability of the base material. Alternatively, only the organic solvent may be used. Such organic solvents include methanol, ethanol, propanol, acetone, methyl ethyl ketone,
Dioxane, ellalen glycol, propylene glycol, glycerin, methyl carbitol, ethyl carbitol butyl carbitol, methyl cellosolve, ethyl cellosolve, acetic acid, acetic acid ester of the alcohol, acetic acid ester of the carbitol and acetic acid ester of the cellosolve Kind and the like. When such an organic solvent is used in combination, it is preferably used in the range of 50% by weight (hereinafter abbreviated as “%”) of the entire medium from the viewpoint of the safety of the resulting aqueous primer solution. It is preferably used in the range of not more than%. When the above organic solvent is used, it may be recovered by distillation or the like after completion of the polymerization reaction.

In addition, as the cationic alkali cross-linking type monomer (component A) represented by the general formula (I), a halogenated salt of a dimethylaminomethylacrylamide epichlorohydrin adduct or a halogenated salt of a dimethylaminomethylmethacrylamide epichlorohydrin adduct. Salts, halogenated salts of dimethylaminopropylacrylamide epichlorohydrin adducts and alkyl sulfonates, halogenated salts of dimethylaminopropylmethacrylamido epichlorohydrin adducts, alkylsulfonates, halogenated salts of dimethylaminomethyl acrylic ester epichlorohydrin adducts, Dimethylaminomethyl methacrylic ester epichlorohydrin adduct halogenated salt, dimethylaminopropyl acrylic ester epichlorohydrin adduct halogenated salt , Halogenated salt and alkyl sulfonate salt of dimethylaminopropyl methacrylamide ester epichlorohydrin adduct, or Q in the epoxide material (Formula "I" corresponding to their Compounds that are

And it is necessary to mix | blend the said cationic alkali bridge | crosslinking type monomer in a ratio of 5% or more with respect to all the monomers. That is, the cationic alkali cross-linking monomer is 5
If it is less than%, the strength of the obtained film and the adhesion with the topcoat paint and the adhesive become insufficient.

On the other hand, as the alkoxysilane monomer (component B) represented by the general formula (II), vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-
Methacryloxypropyltrimethoxysilane and the like can be mentioned. The above alkoxysilane monomer is based on all monomers
It is necessary to mix it in a proportion of 0.5% or more. That is, when the content of the alkoxysilane monomer is less than 0.5%, the strength of the obtained film and the adhesion and adhesiveness with the topcoat paint and the adhesive are insufficient, as in the case of the above-mentioned cationic alkali crosslinkable monomer. Because.

Further, as the ethylenically unsaturated monomer which can be used together with the above-mentioned A component and B component, there are used hydrophobic monomer such as vinyl acetate, acrylic acid alkyl ester, methacrylic acid alkyl ester, styrene, acrylonitrile and methacrylonitrile. I can raise my body. These may be used alone or in combination of two or more. When a polymer is produced by using the ethylenically unsaturated monomer, acrylic acid, methacrylic acid, amides of acrylic acid or methacrylic acid, methylolated amides, Alkoxymethylated amides, alkylaminoesters, cationic alkali crosslinkable monomers represented by the general formula (I), hydrophilic monomers such as monochlorovinyl acetate and 1-chloro-2-hydroxypropyl acrylate. Are used together. These may be used alone or in combination of two or more. Needless to say, the above-mentioned hydrophilic monomer is used within such a range that the polymer produced is not soluble in the aqueous medium. The above ethylenically unsaturated monomer is copolymerized with the component (A) and the component (B), or emulsion polymerized separately from the component (A) and the component (B) to obtain a polymer (emulsion). , This (A) +
When mixed with the medium containing the copolymer (B), the adhesiveness and adhesion between the surface of the base material and the top coating, adhesive, etc. are further improved. In addition, a polymer (emulsion) prepared from the ethylenically unsaturated monomer is mixed with a medium containing a copolymer of (A) + (B) + the ethylenically unsaturated monomer. Also has a similar effect. However, since it is not easy to uniformly mix the two, it is preferable to copolymerize the three as much as possible.

The aqueous solution for a primer of the present invention can be produced using the above medium and monomers, for example, as follows. That is, first, in a water or an organic solvent or a mixture of water and an organic solvent as a polymerization medium, a polymerization initiator is added, while maintaining the system acidic with an acid, the cationic alkali crosslinkable monomer, The alkoxysilane monomer and the ethylenically unsaturated monomer are added dropwise at 60 to 90 ° C. for 1 to 5 hours for polymerization. If necessary, in advance
A chain transfer agent such as 2-mercaptoethanol is added for the purpose of controlling the molecular weight. Further, after the polymerization, various additives, for example, a film-forming aid such as butyellosolve, butyl carbitol, and acetate, a defoaming agent, a pigment, a thickener, and the like can be added, if necessary. In this way,
It is possible to obtain the intended aqueous liquid for a primer.

When emulsion-polymerizing the ethylenically unsaturated monomers separately, a known emulsion-polymerization method may be used. Then, the emulsion obtained is mixed with the above-mentioned copolymer (A + B or A + B + copolymer comprising ethylenically unsaturated monomer) -containing medium to obtain the intended aqueous liquid for primer.

Further, in the above production method, it is necessary to select and use a medium that does not disturb the polymerization reaction. Examples of the polymerization initiator include benzoyl peroxide, azobisisobutyronitrile, 2,2'-azobisaminodipropane hydrochloride and ammonium persulfate. Furthermore, maintaining the medium acidic is important for preventing the system from gelling during polymerization, and as an acid for pH adjustment,
Examples thereof include organic acids such as formic acid, acetic acid and oxalic acid, and inorganic acids such as hydrochloric acid, sulfuric acid and nitric acid.

The aqueous primer solution of the present invention obtained as described above is applied as a primer to the surface of an inorganic substrate such as concrete, mortar, slate plate, silica plate, ALC plate and the like. This coating solution quickly penetrates into the surface layer of the substrate as the medium penetrates, and during the drying process, the functional groups activated by alkali and moisture crosslink to form a third-order coating with excellent water resistance and alkali resistance. It becomes a strong film with the original network structure. As a result, the base material is provided with the same robust and durable reinforcement as that obtained by using the solvent-based primer. Moreover, since the aqueous solution for a primer of the present invention uses a hydrophilic medium, it does not evaporate a toxic solvent, is excellent in safety and pollution prevention, and is extremely practical. . Moreover, since the aqueous solution for a primer of the present invention has a part of its constituent component as a cation, due to its cationic property, the primer coating layer is further applied to the top coating composition or adhesive. It has high affinity and adhesion, and the surface finishing layer can be firmly integrated with the substrate.

 Next, examples will be described together with comparative examples.

[Examples 1 to 6 and Comparative Examples 1 to 4] 40 parts by weight of isopropyl alcohol (hereinafter abbreviated as "part") and 10 parts of water were placed in a four-necked flask equipped with a stirring blade, a thermometer and a reflux condenser. Then, 1 part of azobisisobutyronitrile which is a polymerization initiator and 0.7 part of lauryl mercaptan which is a chain transfer agent were added thereto. Then, the monomer raw material having the composition shown in Table 1 below was put into the dropping funnel, and the mixture was added dropwise with stirring at the reflux temperature of isopropyl alcohol over 3 hours to carry out a polymerization reaction, and further for 3 hours. Completed the reaction. The polymer-containing liquids thus obtained are all uniform solutions, having a polymer concentration of 50% and a viscosity of 500 to 2000 cps (BM type viscometer, 30
C.) and pH = 4.

[Control Examples 1 and 2] As a control product, an acrylic emulsion primer (Acryset EMN-17E, manufactured by Nippon Shokubai Kogyo Co., Ltd.) which has been conventionally used as a primer solution [Control Example 1], an alkali cross-linking type polyacrylic acid ester Emulsion (Primal E-1126, manufactured by Rohm & Haas) [Control Example 2] was prepared.

Asbestos cement calcium silicate board (pH = 9, specific gravity 0.7) and neutralized asbestos cement calcium silicate board (the above-mentioned asbestos cement calcium silicate board is dry ice) Each of which had been sealed and left for 1 week to lower the pH from 9 to 7),
It was applied at a rate of about 120 g / m ² and left to dry at room temperature for 30 minutes. Then, an acrylic paint (topcoat paint) was applied thereon from above at a rate of about 130 g / m ² , and allowed to stand at room temperature for 1 week to be sufficiently dried. Next, this coated surface is 2 mm
25 in a 1 cm square by dividing it into squares.
I made individual micro-compartments. Then, an adhesive tape (Nichiban cellophane tape, width 24 mm) was pressure-bonded to the surface and then peeled off, and the number of minute sections remaining on the substrate side (residual section number) was counted. With this, the adhesiveness between the primer layer and the top coating material was evaluated.

Also, after drying, the sample should be
After immersion in 20 ° C. water for 24 hours, the adhesion was evaluated in the same manner as above.

 The results are shown in Table 2 below.

From the above results, it can be seen that each of the example products has superior performance to the comparative product and the control product.

[Examples 7 to 9 and Comparative Example 5] An emulsion polymer (Emulsion C) having the following composition was produced and mixed with the product of Example 4 described above in a composition shown in Table 3 below to give an aqueous primer solution. A liquid was obtained.

<Composition of Emulsion C> 50 parts of butyl acrylate 48 parts of methyl methacrylate 48 parts of dimethyl diallyl ammonium chloride 2 parts of Emulgen 935 (manufactured by Kao Corporation) 4 parts of water 156 parts Ammonium persulfate 0.3 parts <General properties of Emulsion C> Nonvolatile content 38.2% Viscosity 200 cps pH 2.8 Minimum film forming temperature 5 ° C. Next, the characteristics of the aqueous primer liquid obtained as described above were evaluated in the same manner as in Example 1. The results are also shown in Table 3 below.

From the above results, it is understood that a good primer can be obtained even if an insoluble polymer emulsion is separately prepared and mixed with the product of the above example.

〔The invention's effect〕

As described above, the aqueous solution for a primer of the present invention contains a copolymer obtained by mixing two kinds of special monomers in a specific ratio, and the crosslinking reaction is performed regardless of the alkalinity of the base material. To form a strong film with excellent water resistance and alkali resistance. Therefore, even though it is water-based, it has an excellent base material reinforcing effect equivalent to or better than that of the conventional solvent-type primer, and is safe and does not become a pollution source. Furthermore, it has an excellent effect that it exerts affinity for a top-coat paint, an adhesive, etc., and a finish layer formed on the surface of the base material is firmly integrated with the surface of the base material.

Claims (3)

(57) [Claims] 1. A medium contains a copolymer obtained by copolymerizing the following component (A) in an amount of 5 to 99.5% by weight and the following component (B) in an amount of 0.5 to 95% by weight. An aqueous solution for a primer, which is characterized in that (A) A cationic alkali crosslinkable monomer represented by the following general formula (I). R: H or CH ₃ Y: Organic or inorganic monovalent anion n: integer of 1 to 3 (B) An alkoxysilane monomer represented by the following general formula (II). R: H or CH ₃ Z: CH _{2 n} or However, n is 0 to 3 X: -OCH ₃ or -OC ₂ H ₅ or -OC ₂ H ₄ OCH ₃ 2. The above-mentioned component (A) is copolymerized in the medium in an amount of 5% by weight or more, the above-mentioned component (B) is 0.5% by weight or more, and the ethylenically unsaturated monomer is 94.5% by weight or less. An aqueous liquid for a primer, which comprises the following copolymer. 3. The primer aqueous solution according to claim 1 or the primer aqueous solution according to claim 2,
An aqueous liquid for a primer, which comprises a polymer obtained by polymerizing an ethylenically unsaturated monomer dispersed therein.