JPH03229766A - Aqueous primer solution - Google Patents

Abstract

PURPOSE:To obtain an aqueous primer solution which excels in an ability to penetrate into a base, an ability to reinforce it, etc., and can form a strong film on a base irrespectively of its alkalinity by mixing a medium with a copolymer comprising two monomers in a specified ratio. CONSTITUTION:An aqueous primer solution is obtained by mixing a medium with a copolymer prepared by copolymerizing 5-99.5wt.% cationic alkali- crosslinkable monomer of formula I (wherein R is H or CH3; Q is a group of formula II or III; X is halogen; z is a group of formula IV or V; Y is an organic or inorganic monovalent anion; and n is 1-3) with 0.5-95wt.% alkoxysilane monomer of formula VI [wherein R is H or CH3; z is a group of formula VII or VIII (wherein n is 0-3); and X is -OCH3, -OC2H5 or -OC2H4 OCH3]. This solution can form a strong film on a base (an inorganic building material) irrespectively of its alkalinity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an aqueous primer solution used for surface modification of porous alkaline inorganic substrates such as concrete and mortar.

[Conventional technology]

Cement-based inorganic building materials such as concrete, mortar, and slate boards have fragile surface layers, so a primer liquid is applied to the surface in order to strengthen the surface layer and improve adhesion and adhesion to surface finishing paints, etc. Coating is being done. As such a primer liquid, a solvent type primer liquid in which a synthetic resin is dissolved in an organic solvent has conventionally been used. However, since the solvent in the solvent-based primer liquid is volatile, it is easily flammable and has many problems in terms of safety and hygiene, such as having an adverse effect on the human body when inhaled. Therefore, the present applicant has developed an aqueous primer solution that uses water as a medium without using an organic solvent, and has already filed an application (Japanese Patent Application No. 80694/1982).

[Problem to be solved by the invention]

However, the above aqueous primer liquid undergoes a crosslinking reaction in an alkaline environment to form an excellent water-resistant film, so there is no problem when using it on general substrates with high alkalinity. However, when applied to a base material with low alkalinity or a neutral base material, a sufficiently durable film cannot be obtained, so an improvement has been sought.

The present invention has been made in view of these circumstances, and provides an aqueous primer solution that has excellent base material permeability, base material reinforcing properties, etc., and is capable of forming a strong film regardless of the level of alkalinity of the base material. Its purpose is to provide.

[Means to solve the problem]

In order to achieve the above object, the present invention copolymerizes the following component (A) in a proportion of 5 to 99.5% by weight and the following component (B) in a proportion of 0.5 to 95% by weight. The first aspect is an aqueous solution for a primer containing a copolymer formed by: (A) a cationic alkali crosslinked monomer represented by the following general formula (I);

R: H or CH3, where X is a halogen atom Y: an organic or inorganic monovalent anion n: an integer of 1 to 3 (B) an alkoxysilane monomer represented by the following general formula (II).

Hz=CH 1 (X) ・・・・・・(II) R: H or CH.

Z knee (-CH#;- or -c -o-+CHzh-
1 However, n is 0 to 3 X Knee OCR, or 10C2H5 or 10C,
H, OCR.

In the medium, 5% by weight or more of the above (A) component and the above (B)
0.5% by weight or more of ingredients, 9% of ethylenically unsaturated monomer
The second gist is an aqueous primer liquid containing a copolymer copolymerized at a proportion of 4.5% by weight or less,
The third aspect 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.

[Effect]

In other words, the present inventors investigated a series of water-soluble resins, particularly acrylic resins, in order to find an aqueous primer solution that can form a durable and strong film regardless of the type of base material (inorganic building material). conducted research. As a result, special monomers (
When components A and B) are copolymerized in a specific ratio, the resulting chain polymer exhibits good solubility in water, and the aqueous solution penetrates well into the surface layer of the base material, making it waterproof. sex.

It was discovered that a film with excellent alkali resistance was formed. It was also found that the film reinforced the base material surface with high strength, and at the same time had excellent adhesion and adhesion with the top coating film and adhesive layer.

The reason why the film obtained from the aqueous primer solution of the present invention has such high strength as described above is considered to be due to the following reasons. That is, the polymer component of the present invention derived from the cationic alkali crosslinked monomer (component A) represented by the general formula (1) is activated by the alkali in the base material in an alkaline environment. , a crosslinking reaction occurs between the chain polymers to form a three-dimensional network structure film. Also,
The polymer 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 hydrolyzed product is During drying after application, a crosslinking reaction occurs as water evaporates, forming a three-dimensional network structure film. Therefore, when the aqueous primer solution of the present invention is used on a nearly neutral base material, the components derived from the alkoxysilane monomer cause a crosslinking reaction to form a film with excellent water resistance and alkali resistance. Also, when used in a base material with high alkalinity, due to the synergistic effect of the crosslinking reaction by the components derived from the cationic alkali crosslinking monomer and the crosslinking reaction by the components derived from the alkoxysilane monomer,
This increases the crosslinking density and forms a film with excellent water resistance and alkali resistance. Therefore, the surface of the base material is reinforced with high strength. Moreover, since this film has cationic structural units derived from the above-mentioned cationic alkali crosslinked monomer, it has good adhesion and adhesion with top coats, adhesives, etc. that can be applied on top of this film. It also improves sex. In addition, the above two types of special monomers (A component, B component),
It has been found that copolymerization with an ethylenically unsaturated monomer improves the adhesion and adhesion of the -layer film to the finishing layer.

In addition, the ethylenically unsaturated monomer is polymerized alone by emulsion polymerization or the like, and then added to a copolymer-containing solution of (A) + (B) or (A) + (B) + ethylenically unsaturated monomer. It has been found that similar effects can be obtained by mixing with a copolymerization-containing liquid.

Next, the present invention will be explained in detail.

Water is the most suitable medium for use in the present invention.

However, for the purpose of increasing the solubility of the cationic alkali crosslinked monomer to be copolymerized or increasing the permeability into the substrate, an organic solvent easily soluble in water may be used in combination. Alternatively, only an organic solvent may be used. Such organic solvents include methanol, ethanol, propatool, acetone, methyl ethyl ketone, dioxane, elalen gelicol, propylene glycol, glycerin, methyl calpitol, ethyl calpitol, butyl calpitol, methyl cellosolve, ethyl cellosolve, acetic acid, Examples include the acetate esters of the alcohols, the acetates of carpitol, and the acetates of cellosolve. When such an organic solvent is used in combination, from the viewpoint of the safety of the resulting aqueous primer liquid, it is preferable to use it within the range of 50% by weight (hereinafter abbreviated as "%") of the entire medium, particularly 20% by weight. % or less. In addition, when the above-mentioned organic solvent is used, it may be recovered by distillation or the like after the polymerization reaction is completed.

Further, as the cationic alkali crosslinked monomer (component A) represented by the general formula (1), halogenated salts of dimethylaminomethylacrylamide epichlorohydrin adducts, halogenated salts of dimethylaminomethylmethacrylamide epichlorohydrin adducts, etc. salts, halogenated salts and alkyl sulfonates of dimethylaminopropyl acrylamide epichlorohydrin adduct, halogenated salts and alkyl sulfonates of dimethylaminopropyl methacrylamide epichlorohydrin adduct.

Halogenated salts of dimethylaminomethyl acrylic ester epichlorohydrin adducts, halogenated salts of dimethylaminomethyl methacrylic ester epichlorohydrin adducts, halogenated salts of dimethylaminopropyl acrylic ester epichlorohydrin adducts, halogenated salts of dimethylaminopropyl methacrylic ester epichlorohydrin adducts Salts and alkyl sulfonates, or epoxides corresponding to them (the above general formula (1), and the above cationic alkali crosslinked monomers should be blended in a proportion of 5% or more based on the total monomers) is necessary.

That is, if the content of the cationic alkali crosslinked monomer is less than 5%, the resulting film will have insufficient strength and adhesion to the top coat and adhesive.

On the other hand, examples of the alkoxysilane monomer (component B) represented by the general formula (II) include vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane,
-Methacryloxypropyltrimethoxysilane and the like. The alkoxysilane monomer needs to be blended in a proportion of 0.5% or more based on the total monomers. That is, if the alkoxysilane monomer content is less than 0.5%,
This is because, as in the case of the above-mentioned cationic alkali crosslinked monomer, the strength of the resulting film and the adhesion and adhesion to the top coat and adhesive will be insufficient.

Furthermore, as ethylenically unsaturated monomers that can be used with the above components A and B, hydrophobic monomers such as vinyl acetate, alkyl acrylates, alkyl methacrylates, styrene, acrylonitrile, methacrylonitrile, etc. I can give you my body. These may be used alone or in combination of two or more. In addition, when producing a polymer using the above-mentioned ethylenically unsaturated monomer, acrylic acid is used together with the above-mentioned hydrophobic monomer.

Methacrylic acid, amides of acrylic acid or methacrylic acid, methylolated amides, alkoxymethylated amides, alkylamino esters, cationic alkali crosslinked monomers represented by the above general formula (1), monochlorovinyl acetate , l-chloro-2-hydroxypropyl acrylate and other hydrophilic monomers are used in combination. These may also be used alone or in combination of two or more. Needless to say, the above-mentioned hydrophilic monomers are used within such a range that the resulting polymer does not become soluble in an aqueous medium. The ethylenically unsaturated monomer is copolymerized with the (A) component and (B) component, or is emulsion polymerized separately from the (A) component and (B) component to form a polymer (emulsion). When mixed with a medium containing the copolymer (A) + (B), the adhesion between the surface of the substrate and the top coat, adhesive, etc.

Adhesion is further improved. Further, a polymer (emulsion) made from the above ethylenically unsaturated monomer is mixed into a medium containing a copolymer of (A) ± (B) + the above ethylenically unsaturated monomer. also has a similar effect.

However, it is not easy to mix the two uniformly, so
It is preferable to copolymerize the king.

The aqueous primer solution of the present invention can be produced using the above medium and monomer, for example, in the following manner. That is, first, a polymerization initiator is added to a polymerization medium of water or an organic solvent, or a mixture of water and an organic solvent, and while the system is kept acidic with an acid, the cationic alkali crosslinked monomer and alkoxysilane are added. The monomer and ethylenically unsaturated monomer are added dropwise at 60-90°C over 1-5 hours to polymerize. Note that, if necessary, a chain transfer agent such as 2-mercaptoethanol is added in advance for the purpose of controlling the molecular weight. Further, after the polymerization, various additives such as film-forming aids such as butyl cellosolve, butyl carpitol, acetate, antifoaming agents, pigments, thickening inhibitors, etc. can be added as necessary. In this way, the desired aqueous primer solution can be obtained.

In addition, when emulsion polymerizing the ethylenically unsaturated monomer separately, a known emulsion polymerization method may be followed. and,
The obtained emulsion is mixed with the above copolymer (A+B or A+B copolymer consisting of ten ethylenically unsaturated monomers)
By mixing it with the containing medium, the desired aqueous primer liquid can be obtained.

Further, in the above production method, it is necessary to select and use a medium that does not interfere with the polymerization reaction. and,
Examples of the polymerization initiator include benzoyl peroxide, azobisisobutyronitrile, 2,2'abbisaminodipropane hydrochloride, and ammonium persulfate. Furthermore, it is important to maintain the above-mentioned medium acidic in order to prevent the system from gelling during polymerization, and acids for pH adjustment include organic acids such as formic acid, acetic acid, and oxalic acid, as well as hydrochloric acid. , sulfuric acid.

Examples include inorganic acids such as 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 board, Keikal board, ALC board, etc. This coating solution quickly penetrates into the surface layer of the base material as the medium penetrates, and during the drying process, the functional groups activated by alkali and moisture crosslink, resulting in water resistance,
It forms a strong film with a three-dimensional network structure that has excellent alkali resistance. The result is a robust and durable reinforcement to the substrate similar to that achieved using solvent-based primers. Furthermore, since the aqueous primer liquid of the present invention uses a hydrophilic medium, no toxic solvents will volatilize, and it is excellent in terms of safety and pollution prevention, and is extremely practical. . Moreover, since some of the constituent components of the aqueous primer liquid of the present invention are cationic, due to its cationic nature, it is resistant to top coats, adhesives, etc. that are further applied on the primer coating layer. affinity.

It has high adhesion and allows the surface finishing layer to be firmly integrated with the base material.

Next, examples will be described together with comparative examples.

[Examples 1 to 6, Comparative Examples 1 to 4] 40 parts by weight of isopropyl alcohol (hereinafter abbreviated as "parts") and 10 parts of water were put into a four-loop flask equipped with a stirring blade, a thermometer, and a reflux condenser. Then, 1 part of azobisisobutyronitrile as a polymerization initiator and 0.7 part of lauryl mercaptan as a chain transfer agent were added thereto. Then, a monomer raw material having the composition shown in Table 1 below was put into the dropping funnel, and the polymerization reaction was carried out by dropping it under stirring at the reflux temperature of isopropyl alcohol over 3 hours, and then for another 3 hours. A complete reaction was carried out. The polymer-containing liquids obtained in this way are all homogeneous solutions, with a polymer concentration of 50% and a viscosity of 500 to 2000 cps (
BM type viscometer, 30°C), pH was -4.

(Left below): Comparative Examples 1 and 2) As a control product, an acrylic emulsion primer (Acryset EMN-17E, manufactured by Nippon Shokubai Kogyo Co., Ltd.), which is conventionally used as a primer liquid, was used as a control example 3]
, alkali crosslinked polyacrylic acid ester emulsion (Blymar E-1126, manufactured by Rohm & Haas) (
Comparative Example 2] was prepared.

These example products, comparative example products, and control example products were tested on an asbestos cement calcium silicate board (pH = 9, specific gravity 0.7) and a neutral fossil wool cement calcium silicate board (the above asbestos cement calcium silicate board). Sealed in tri-ice 1
After being left for a week, the pH was lowered from 9 to 7), the solution was applied at a rate of about 120 g/bottom, and left at room temperature for 30 minutes to dry. Then, apply acrylic paint (top coat) at a rate of about 130 g/m over it,
It was left to stand at room temperature for one week to be sufficiently dried.

Next, this painted surface was divided into base grids with intervals of 211I11 to create 25 microdivisions within a square of ICl11. Then, a cellophane tape (width 24 mm) was applied to the surface of the adhesive tape and then peeled off, and the number of minute sections remaining on the substrate side (number of remaining sections) was counted. This evaluated the adhesion between the primer layer and the top coat.

In addition, after drying and before dividing the painted surface, two samples should be
After soaking in water at 0°C for 24 hours, adhesion was evaluated in the same manner as above.

These results are shown in Table 2 below.

(Hereinafter, blank spaces) From the above results, it can be seen that all the examples have superior performance compared to the comparative example and the control example.

J Examples 7 to 9, Comparative Example 5] An emulsion polymer (emulsion C) was prepared with the following composition,
An aqueous primer solution was obtained by mixing the above Example 4 product with the composition shown in Table 3 below.

Composition of emulsion C> Butyl acrylate 50 parts Methyl methacrylate 48 parts Methyl ammonium chlorite Emulgen 935 (manufactured by Kao Corporation) Ammonium hydropersulfate General properties of emulsion C> Non-volatile content 38.2% Viscosity 200 cps p H2.8 4〃 56 0.3〃 Minimum film forming temperature 5°C Next, the properties 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.

(The following is a blank space) From the above results, it can be seen that a good primer can be obtained even if an insoluble polymer emulsion is prepared separately and mixed with the above-mentioned separate product.

〔Effect of the invention〕

As described above, the aqueous primer liquid of the present invention contains a copolymer formed by blending two types of special monomers in a specific ratio, and the crosslinking reaction occurs regardless of the alkalinity of the base material. , forming a strong film with excellent water resistance and alkali resistance. Therefore, although it is water-based, it has an excellent base material reinforcing effect equal to or better than that of conventional solvent-based primers, is safe, and does not become a source of pollution. Furthermore, it exhibits affinity for top coats, adhesives, etc., and has the excellent effect of firmly integrating the finishing layer formed on the surface of the substrate with the surface of the substrate.

Claims (3)

[Claims] (1) The medium contains a copolymer obtained by copolymerizing the following component (A) in a proportion of 5 to 99.5% by weight and the following component (B) in a proportion of 0.5 to 95% by weight. An aqueous primer liquid that is characterized by: (A) A cationic alkali crosslinked monomer represented by the following general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ... (I) R: H or CH_3 Q: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼ However, X is a halogen atom Z: ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ Mathematical formulas,
Chemical formulas, tables, etc. are available ▼ Y: Organic or inorganic monovalent anion n: Integer from 1 to 3 (B) Alkoxysilane monomer represented by the following general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼・・・・・・(II) R: H or CH_3 Z: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲Mathematical formulas,
There are chemical formulas, tables, etc. ▼ However, n is 0 to 3 X: -OCH_3 or -OC_2H_5 or -O
C_2H_4OCH_3 (2) Copolymerizing the above component (A) in a proportion of 5% by weight or more, the above (B) component in a proportion of 0.5% by weight or more, and an ethylenically unsaturated monomer in a proportion of 94.5% by weight or less in a medium. An aqueous primer liquid characterized by containing a copolymer formed by: (3) A polymer obtained by polymerizing an ethylenically unsaturated monomer is dispersed in the aqueous primer liquid according to claim (1) or the aqueous primer liquid according to claim (2). An aqueous primer solution characterized by: