JPH06166830A - Water-base liquid for primer - Google Patents

Abstract

PURPOSE:To obtain the subject liq. which has capabilities of penetrating into and reinforcing a substrate, water resistances, and durability respectively equivalent to those of a solvent-base primer by incorporating a copolymer of a specific cationic alkali-crosslinkable monomer with a specific alkoxysilane monomer into an aq. medium. CONSTITUTION:This water-base lip. is obtd. by incorporating, into an aq. medium, a copolymer which is obtd. 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 (wherein X is halogen) or III; Z is a group of formula IV or V; Y is an org. or inorg. 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 VI or VIII (wherein (n) is 0-3); X is OCH3, OC2H5, or a group of formula IX (wherein (m) and (p) are each 1-3); Y is a group of formula X (wherein (q) is 0-3); and (a) is 1 or 2].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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.

[0002]

BACKGROUND ART Cement-based inorganic building materials such as concrete, mortar, and slate boards have weak surface layers, so that they are reinforced and have an adhesive force to paint for surface finishing.
For the purpose of improving the adhesion, a primer solution is applied to the surface of the surface. 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, it is easily ignited and has a harmful effect on the human body due to inhalation.
There are many problems in safety and hygiene. Therefore, the present applicant has developed and has already applied for an aqueous primer liquid using water as a medium without using an organic solvent (Japanese Patent Application No. 62-80694).
issue). In addition, as this improved product, we have developed a new aqueous solution for a primer that is copolymerized with an alkoxysilane-containing monomer, and are crosslinked regardless of the alkalinity of the base material to create an aqueous resin that is excellent in reinforcing the surface layer of the base material. Has already applied for (Japanese Patent Application No. 3-229766).

[0003]

However, in the above-mentioned aqueous liquid for primer, the crosslinkable monomer which is a copolymerization component is also a hydrophilic monomer itself, and a non-crosslinked functional group is contained in the dry coating film. In many cases, groups and the like remain as hydrophilic components, and the water resistance of the coating film is not as high as that of the solvent-based primer under the present circumstances.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an aqueous primer liquid having the same substrate permeability, substrate reinforcement, water resistance, and durability as solvent-based primers. And

[0005]

In order to achieve the above-mentioned object, the present invention comprises the following components (A) 5-9 in a medium.
9.5% by weight, 0.5 to 95% by weight of the following component (B)
The first gist is an aqueous solution for a primer containing a copolymer obtained by copolymerization at a ratio of.

(A) A cationic alkali crosslinkable monomer represented by the following general formula (1).

[Chemical 3]

(B) An alkoxysilane monomer represented by the following general formula (2).

[Chemical 4]

In the medium, the component (A) is contained in an amount of 5% by weight or more, the component (B) is contained in an amount of 0.5% by weight or more, and the ethylenically unsaturated monomer is contained in an amount of 94.5% by weight or less. The second gist is an aqueous solution for a primer containing a copolymer obtained by copolymerization, and one of the above two types of the aqueous solution for a primer is polymerized with an ethylenically unsaturated monomer. A third aqueous primer solution containing dispersed aggregates
The summary of

[0009]

In other words, the present inventors have found that a water-soluble resin for a primer is formed to form a durable and strong film regardless of the type of base material (inorganic building material) and to have an extremely excellent water resistance. In particular, we have conducted a series of research focusing on acrylic resins. As a result, the general formula (1),
When the special monomer represented by (2) (component A, component B) is copolymerized at a specific ratio, the chain polymer obtained exhibits good solubility in water and its aqueous solution. It has been found that satisfactorily penetrates into the surface layer of the base material and reinforces the surface of the base material with high strength, and at the same time, the dry film has water resistance equivalent to that of the solvent-based primer. It was also found that due to the cationic property of the general formula (1), the adhesiveness and adhesion to the coating film of the topcoat paint and the adhesive layer are excellent.

The reason why the film obtained from the aqueous liquid for a primer of the present invention has high water resistance and 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 (1) of the present invention is activated by the alkali in the base material in an alkaline environment. ,
A cross-linking reaction occurs between the chain polymers to form a three-dimensional network structure film. Further, a polymer constituent component derived from an alkoxysilane monomer (component B) in which an alkyl group having 1 to 3 carbon atoms is bonded to the silane represented by the general formula (2) is added to the aqueous liquid. Alkoxy groups are hydrolyzed by the water present, and the hydrolysis product causes a cross-linking reaction with the evaporation of water during the drying after the application of the aqueous liquid, and also forms a three-dimensional network structure film. Further, since the functional group is hydrophobized by the presence of the alkyl group, the water resistance of the three-dimensional network structure film is further improved. Therefore, the aqueous primer solution of the present invention, when applied to a substrate, undergoes a cross-linking reaction by a component derived from the cationic alkali cross-linking monomer and a cross-linking reaction by a component derived from an alkoxysilane monomer. The synergistic effect increases the crosslink density, reinforces the base material surface with high strength, and develops water resistance. The water resistance of the film is further improved by the effect of the alkyl group bonded to the silane.

Moreover, since this film has a cationic constitutional unit derived from the above-mentioned cationic alkali cross-linking type monomer, it is adhered to a topcoat paint, especially an anionic paint, which can be applied on the film. Excellent in adhesion and adhesion. The above two types of special monomers (A component, B
It was found that when the (component) and an ethylenically unsaturated monomer are copolymerized, the adhesion and the adhesion to the finishing layer of the coating are further improved. The above-mentioned ethylenically unsaturated monomer is polymerized by emulsion polymerization or the like alone, and this is mixed with a (A) + (B) copolymer-containing liquid or (A) +
It was found that the same effect can be obtained by mixing with the copolymer-containing liquid of (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, an easily soluble organic solvent may be used in combination with water for the purpose of enhancing the solubility of the cationic alkali cross-linking monomer to be copolymerized or enhancing the permeability to the substrate. Alternatively, only an easily soluble organic solvent in water may be used. Such organic solvents include methanol, ethanol, propanol, acetone, methyl ethyl ketone, dioxane, ethylene glycol, propylene glycol, glycerin, methyl carbitol, ethyl carbitol, butyl carbitol,
Examples thereof include methyl cellosolve, ethyl cellosolve, acetic acid, acetic acid esters of the above alcohols, acetic acid esters of the above carbitol, and acetic acid esters of the above cellosolve. 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 obtained aqueous solution for a primer, and particularly 20 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 the completion of the polymerization reaction.

The cationic alkali crosslinkable monomer (component A) represented by the general formula (1) is a halogenated salt of a dimethylaminomethylacrylamide epichlorohydrin adduct or a dimethylaminomethylmethacrylamide epichlorohydrin adduct. Halogenated salts of dimethylaminopropylacrylamide epichlorohydrin adducts and alkyl sulfonates, halogenated salts of dimethylaminopropylmethacrylamido epichlorohydrin adducts and alkyl sulfonates,
Dimethylaminomethyl acrylic ester epichlorohydrin adduct halogenated salt, dimethylaminomethyl methacrylic ester epichlorohydrin adduct halogenated salt, dimethylaminopropyl acrylic ester epichlorohydrin adduct halogenated salt, dimethylaminopropyl methacryl ester epichlorohydrin adduct halogenated salt Examples include salts and alkyl sulfonates, or epoxides corresponding to them. As such an epoxide body, Q in the general formula (1) is used.
Is a compound represented by the following formula (3).

[0015]

[Chemical 5]

It is necessary that the above-mentioned cationic alkali cross-linking type monomer is blended in a proportion of 5% or more based on all the monomers. That is, if the amount of the cationic alkali crosslinkable monomer is less than 5%, the strength of the obtained film and the adhesion with the topcoat paint and the adhesive will be insufficient.

On the other hand, examples of the alkoxysilane monomer (component B) represented by the general formula (2) include vinylmethyldiethoxysilane, vinyldimethylmethoxysilane, vinylmethyldiethoxysilane, vinyldimethylethoxysilane, vinylmethyldivinylsilane. (2-methoxyethoxy) silane, vinyldimethyl (2-methoxyethoxy) silane,
3-methacryloxypropylmethyldimethoxysilane,
Examples thereof include 3-methacryloxypropyl dimethylmethoxylan. The above-mentioned alkoxysilane monomer needs to be blended in a proportion of 0.5% or more with respect to all the monomers. That is, when the content of the alkoxysilane monomer is less than 0.5%, the water resistance and strength of the obtained film and the adhesion and adhesiveness to the topcoat paint and the adhesive are the same as in the case of the above-mentioned cationic alkali crosslinkable monomer. Is insufficient.

Further, as the ethylenically unsaturated monomer which can be used together with the above-mentioned A component and B component, vinyl acetate, acrylic acid alkyl ester, methacrylic acid alkyl ester, styrene, acrylonitrile, methacrylonitrile, etc. are hydrophobic. Examples of the monomer include a polymerizable monomer. These may be used alone or in combination of two or more. When a polymer is produced from the ethylenically unsaturated monomer, the hydrophobic monomer is used together with acrylic acid, methacrylic acid, amides of acrylic acid or methacrylic acid, methylolated amides, and alkoxymethyl. Amides, alkylaminoesters, cationic alkali crosslinkable monomers represented by the general formula (1), hydrophilic monomers such as monochlorovinyl acetate and 1-chloro-2-hydroxypropyl acrylate are used in combination. To be done. 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). When this is mixed with the medium containing the copolymer of (A) + (B), the adhesiveness and adhesion between the surface of the base material and the topcoat paint, adhesive, etc. are further improved. Also, (A)
+ (B) + Even if a polymer (emulsion) made from the ethylenically unsaturated monomer is mixed with a medium containing a copolymer of the ethylenically unsaturated monomer, the same effect can be obtained. There is. 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, for example, as follows using the above medium and monomers. That is, first, in a mixture of water or an organic solvent or a mixture of water and an organic solvent as a polymerization medium, while adding a polymerization initiator, while maintaining the system acidic by an acid,
The cationic alkali crosslinkable monomer, the alkoxysilane monomer and the ethylenically unsaturated monomer are added at 60 to 90 ° C.
Then, the mixture is added dropwise over 1 to 5 hours for polymerization. If necessary, a chain transfer agent such as 2-mercaptoethanol is added in advance for the purpose of adjusting the molecular weight. In addition, after the polymerization, if necessary, various additives such as butyl cellosolve, butyl carbitol, and a film-forming aid such as acetate,
Defoaming agents, pigments, thickening inhibitors, etc. can be added.
In this way, the intended aqueous primer liquid can be obtained.

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

Further, in the above production method, it is necessary to select and use a medium which does not inhibit the polymerization reaction. And, as the polymerization initiator, benzoyl peroxide,
Examples thereof include azobisisobutyronitrile, 2,2'-azobisaminodipropane hydrochloride and ammonium persulfate.
Further, it is important to keep the medium acidic so as to prevent gelation of the system during polymerization, and as acids for pH adjustment, formic acid, acetic acid, organic acids such as oxalic acid, and hydrochloric acid. , Inorganic acids such as 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 base material such as concrete, mortar, slate plate, silica plate, ALC plate and the like. This coating solution quickly penetrates into the surface layer of the base material with the penetration of the medium, and in the drying process,
The functional groups activated by alkali and water are crosslinked to form a strong film having a three-dimensional network structure with excellent water resistance and alkali resistance. 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, the aqueous primer solution of the present invention,
Since it uses a hydrophilic medium, it does not evaporate a toxic solvent, is excellent in safety and pollution prevention, and is extremely practical. Furthermore, since the aqueous solution for a primer of the present invention has a part of its constituent components as cations, due to its cationic property, it is not suitable for topcoat paints, adhesives, etc. that are further applied onto the primer coating layer. 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.

[0024]

Examples 1 to 6 and Comparative Examples 1 to 5 In a four-necked flask equipped with a stirring blade, a thermometer and a reflux condenser, 40 parts by weight of isopropyl alcohol (hereinafter abbreviated as "part") and water 1
0 part was added, and 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 and Table 2 below was charged 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. Three
A time-completed reaction was performed. The polymer-containing liquids thus obtained are all uniform solutions and have a polymer concentration of 50.
%, The viscosity is 500 to 2000 cps (BM type viscometer, 30
C.), pH = 4.

[0025]

[Table 1]

[0026]

[Table 2]

[0027]

[Comparative Examples 1 and 2] As a control product, an acrylic emulsion primer which has been conventionally used as a primer solution (Akreset EMN-17E, manufactured by Nippon Shokubai Co., Ltd.)
[Comparative Example 1], an alkali crosslinkable polyacrylic ester emulsion (Primal E-1126, manufactured by Rohm & Haas Co.) [Comparative Example 2] were prepared.

Asbestos cement calcium silicate board (pH = 9, specific gravity 0.7) and neutral asbestos cement calcium silicate board (the above asbestos cement silicate) The calcium plate was sealed in dry ice and left for 1 week, and the pH was lowered from 9 to 7), and then applied at a rate of about 120 g / m ² ,
It was left to dry at room temperature for 30 minutes. Then, about 130 g / m of acrylic paint (top paint)
^It was applied at a ratio of ² and left at room temperature for 1 week to fully dry it. Next, the coated surface was divided into 2 mm intervals in a grid pattern to form 25 minute divisions in a 1 cm square. 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. This evaluated the adhesion between the primer layer and the topcoat paint. Further, after drying and before partitioning the coated surface, the sample was immersed in water at 50 ° C. for 24 hours, and then the hot water adhesion was evaluated in the same manner as above. The results are shown in Tables 3 to 5 below.

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

[Table 5]

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

[0033]

Examples 7 to 9 and Comparative Example 6 An emulsion polymer (emulsion C) having the following composition was prepared and mixed with the product of Example 4 having the composition shown in Table 6 below to give an aqueous primer solution. Got <Composition of Emulsion C> 50 parts of butyl acrylate Methyl methacrylate 48 〃 Dimethyldiallylammonium chloride 2 〃 Emulgen 935 (manufactured by Kao Corporation) 4 〃 Water 156 〃 Ammonium persulfate 0.3 〃 <General properties of Emulsion C> Nonvolatile content 38 0.2% 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 6 below.

[0035]

[Table 6]

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 Examples.

[0037]

INDUSTRIAL APPLICABILITY As described above, the aqueous primer solution of the present invention contains a copolymer prepared by mixing two kinds of special monomers in a specific ratio, and the alkalinity of the substrate is Regardless of this, a crosslinking reaction occurs to form a strong film with excellent water resistance and alkali resistance. Therefore, even though it is water-based, it has an excellent effect of reinforcing the base material, which is equal to or better than the conventional solvent-type primer, and is safe and does not become a pollution source. Further, it has an excellent effect of exerting an affinity for a topcoat paint, an adhesive agent and the like, and firmly integrating a finishing agent layer made of these on the surface of the base material.

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[Procedure amendment]

[Submission date] July 29, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Chemical 1] (B) An alkoxysilane monomer represented by the following general formula (2).

[Chemical 2]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

In order to achieve the above object, the present invention comprises a medium containing a copolymer containing the following components (A) and (B) as main raw materials. Regarding the molecular structure of the united product, the structural unit derived from the component (A) is 5 to 99.5% by weight, and the structural unit derived from the component (B) is 0.5 to 95% by weight of the copolymer. The first gist is an aqueous primer solution which is set to occupy.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Further, in the aqueous medium, the above (A), (B)
And a copolymer mainly composed of the following component (C) is contained, and the molecular structure of this copolymer is such that the structural unit derived from the above component (A) is 5% by weight or more of the copolymer, The structural unit derived from the component (B) is 0.5 of the copolymer.
A second aspect of the invention is an aqueous primer solution in which the structural unit derived from the component (C) accounts for 94.5% by weight or less of the copolymer. The third gist is an aqueous solution for a primer in which a polymer obtained by polymerizing an ethylenically unsaturated monomer is dispersedly contained in any of the aqueous solution for a primer. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 21, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

(B) An alkoxysilane monomer represented by the following general formula (2).

[Chemical 4]

Claims (3)

[Claims] 1. The following component (A) is added to an aqueous medium in an amount of 5 to 5:
An aqueous liquid for a primer, comprising a copolymer obtained by copolymerizing 99.5% by weight of the following component (B) in a proportion of 0.5 to 95% by weight. (A) A cationic alkali crosslinkable monomer represented by the following general formula (1). [Chemical 1] (B) An alkoxysilane monomer represented by the following general formula (2). [Chemical 2] 2. The proportion of the component (A) in the aqueous medium of 5% by weight or more, the component (B) of 0.5% by weight or more and the ethylenically unsaturated monomer of 94.5% by weight or less. An aqueous liquid for a primer, which contains a copolymer obtained by copolymerizing with. 3. A primer comprising a polymer obtained by polymerizing an ethylenically unsaturated monomer dispersedly contained in the aqueous liquid according to claim 1 or the aqueous liquid according to claim 2. Aqueous liquid.