JPH01113471A - Primer - Google Patents

Abstract

PURPOSE:To obtain a primer excellent in adhesion to a wet surface of concrete, by mixing a specified unsaturated silane compound with, optionally, an unsaturat ed isocyanate, a polymerizable monomer, a polymer soluble in this monomer and a curing agent. CONSTITUTION:100 pts.wt. mixture of 5.95wt.% unsaturated silane compound (A) of formula I (wherein R<1> is H or CH3, M is formula II, R<2> is a 2-4C alkylene, n is 0-1, and X is a 1-4C alkoxyl) (e.g., gamma- methacryloxypropyltrimethoxysilane) with, optionally, 95-5wt.% unsaturated isocyanate (B) having a (meth)acryloyl group and an NCO group in the molecule (e.g., a reaction product of 2-hydroxyethyl methacrylate with 2,4-tolylene diisocyanate) is mixed with, optionally, 5-200 pts.wt. polymerizable monomer (C), a monomer (D) soluble in component C, and 0.2-5 pts.wt. curing agent (E) which is preferably a redox system containing an organic peroxide.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to the field of civil engineering and construction, and in particular to a primer for maintenance painting of concrete buildings. This invention relates to a primer suitable for concrete painting, which has extremely strong adhesion to surfaces and has practically sufficient adhesion.

Therefore, the purpose of the present invention is to provide a primer that has excellent adhesion to wet concrete or concrete that has deteriorated over time, to prevent deterioration of concrete structures, to establish a reliable coating system, and to improve the appearance of the concrete by painting. The aim is to bring about improvements in

[Conventional technology]

At present, emulsion-type coatings are mainly used for concrete coatings due to their ease of formulation and application, but they have sufficient adhesion and hardness for practical use, stain resistance, and protection against salt damage. It is no exaggeration to say that paints that can maintain these properties even when extremely wet, especially when they contain concrete components, are now virtually on the market.

[Problem that the invention seeks to solve]

Concrete, unlike metal, is a type of porous material.
In reality, there are countless cracks.

Therefore, paints for this purpose are required to have the ability to follow pores and cracks, and if they also need to serve the purpose of preventing salt damage, they must have the ability to prevent the intrusion of chlorine ions, moisture, oxygen, etc. It won't happen.

Another problem is that the properties of the materials are different between the surface of newly poured concrete and the surface of aged concrete, making it difficult to achieve good paint adhesion, especially when repairing old concrete. There are many things like that.

In this way, the present invention can coat even concrete with pores and cracks with good followability and prevent the intrusion of moisture, oxygen, and other substances, and it also adheres well to old concrete with deteriorated surface that is the target of repair. The aim is to provide a primer with good properties.

[Means and actions for solving the problem] As a result of various studies in order to form a coating film that adheres well to concrete surfaces, especially wet surfaces, and has sufficient durability, the present inventors have discovered the following. What is decisively important is the quality of the primer that impregnates the concrete surface and firmly adheres to the concrete, and the selection of this primer will determine the success or failure of the concrete paint.

Therefore, the present inventors investigated various primer compositions for obtaining reliable adhesion and found that - maximum % formula % () [where R1 is hydrogen or a methyl group, an alkylene group, n is 0 or 1, and X is 1 carbon number
~4 alkoxy group] A primer mainly composed of an unsaturated silane compound represented by the following, and if necessary, an unsaturated isocyanate having a (meth)acryloyl group and an isocyanate group in the molecule, polymerization It has been found that a primer containing a polymerizable monomer, a polymer soluble in the polymerizable monomer, and a curing agent is suitable for these purposes.

We have discovered that by applying and impregnating these primers onto the concrete surface, and simultaneously bonding the alkoxysilane groups and concrete components and polymerizing the unsaturated groups, it is possible to obtain a coating film that adheres extremely strongly to the concrete. We were able to complete the present invention.

The unsaturated silane compound used in the present invention has the following general formula (
A).

R' CH2=C-(M)n Si= (X)l...
(A) [However, R1 is hydrogen or a methyl group, an alkylene group, n is 0 or 1, and X has a carbon number of 1
-4 alkoxy group] These unsaturated silane compounds are commercially available as coupling agents. Typical examples thereof include vinylmethoxysilane, vinylethoxysilane, vinyl-
Tris(betamethoxyethoxy)silane, gamma
Methacryloxypropyltrimethoxysilane, gamma
There is methacryloxypropyltris(betamethoxyethoxy)silane.

Although the primer of the present invention can be impregnated into concrete or cement-based building materials with an unsaturated silane compound alone, it is preferable to apply a radical curing resin thereon and cure it. The purpose can be achieved by copolymerizing the unsaturated group of and the top coating resin, and finally curing the impregnated resin.

Furthermore, in order to expand the effects of the present invention and to fully achieve the purpose no matter what kind of paint is used as the top coat, a radical generating catalyst may be used in combination as necessary, and (meth)acryloyl groups may be added in the molecule. It is possible to take measures such as using a mixture of a polymerizable monomer copolymerizable with an unsaturated isocyanate having an incyanate group and an unsaturated silane compound, or dissolving a polymer in the polymerizable monomer.

The unsaturated silane compounds of the present invention are curable by various means.

For example, the radical generator may be an azo compound, but the adhesion tends to vary.

Photoreaction initiators also show similar tendencies, and are practical when exposed to sunlight, but adhesion becomes insufficient on cloudy days or in areas not exposed to light.

As the curing agent of the present invention, a redox system using an organic peroxide is suitable. Examples of these include (a) acyl peroxide - aromatic tertiary amines, (b) hydroperoxide - vanadium, cobalt, copper,
Examples include organic acid salts or chelate compounds of manganese, (c) ketone peroxide-cobalt, organic acid salts or chelate compounds of vanadium, and (c) is especially useful when used in combination with a small amount of styrene. Become.

Examples of organic peroxides include the following types.

(i) Ketone peroxides methyl ethyl ketone peroxide, cyclohexanone peroxide, methyl acetoacetate peroxide, (ii) Hydroperoxides cumene hydroperoxide, paramenthane hydroperoxide, (iii) Diacyl peroxides lauroyl peroxide, Benzoyl peroxide, methalyl peroxide, (iv>peroxyesters t-butylperoxybivalate, t-butylperoxy 2-ethylhexanate, t-butylperoxybenzoate, these can be used alone, but Mixed use is possible if necessary. However, ketone peroxide and hydroperoxide react with isocyanate groups, rapidly gelling and sometimes foaming, so it is difficult to use them in combination with unsaturated isocyanates. Yes, you will have to rely on spray painting from separate nozzles.

Since diacyl peroxide does not exhibit this phenomenon, it can be used with any coating system.

The amount of organic peroxide used is 0.2 to 5 parts by weight based on 100 parts of the total weight of unsaturated compounds such as unsaturated isocyanates and unsaturated silane compounds, and an appropriate amount is 0.5 parts by weight. ~3 parts by weight.

Examples of the unsaturated isocyanate compound (B) used in the present invention include the following types.

(a) Isocyanate ethyl methacrylate, (b) An unsaturated alcohol obtained by reacting acrylic acid or methacrylic acid with a monoepoxy compound is reacted with a polyvalent isocyanate, and a (meth)acryloyl group is formed through a urethane bond. An unsaturated isocyanate that shares an isocyanate group and an isocyanate group in one molecule.

An example is shown by the following reaction.

(2-7 dorokishety methacrylate) (2,
4-Triresi isocyanate (unsaturated isocyanate) In the production of this type of unsaturated incyanate compound, the reaction molar ratio of unsaturated alcohol and diisocyanate is not necessarily such that the hydroxyl group and the isocyanate group are equivalent. The presence of free diisocyanate is not necessary, and the presence of free diisocyanate is tolerated.

Although it is convenient to carry out the reaction in a solvent or monomer and use it as is, it is not impossible to synthesize without a solvent.

Suitable examples of unsaturated alcohols used in the synthesis of unsaturated isocyanates include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Examples of polyvalent isocyanates include 2.4-tolylene diisocyanate, a mixture of 2,4-tolylene diisocyanate and 2.6-tolylene diisocyanate, tolydine diisocyanate, diphenylmethane diisocyanate, and parafluorinated nylene diisocyanate. Isocyanates, 1,5-naphthylene diisocyanate, 1,6 hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate are used.

The mixing ratio of the unsaturated silane compound (A) and the unsaturated isocyanate compound (B) varies depending on the condition of the concrete, but -m includes 5 to 95 weight (%) of unsaturated silane, unsaturated The isocyanate compound is 95 to 5 (%), preferably the unsaturated silane is 20 to 80 (%), and the unsaturated isocyanate compound is 80 to 20 (%).

Among component (B), unsaturated isocyanates having urethane bonds have excellent adhesion to concrete due to the presence of urethane bonds.

The polymerizable monomer used in the present invention has the effect of improving adhesion and expanding the stress surface, and has the effect of improving adhesion and expanding the stress surface.
Any type that can be copolymerized with the unsaturated bond of unsaturated silyl isocyanate, specifically the (meth)acryloyl group, can be used. Examples of these include the following types:

Styrene, vinyltoluene, chlorostyrene, methacrylic acid esters (methyl methacrylate, isopropyl methacrylate, n-butyl acrylate, isobutyl methacrylate, tert-butyl methacrylate,
2-ethylhexyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate I, etc.), acrylic esters (methylacrylate, etc.).

acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, trimethylolpropane triacrylate, etc.), acrylonitrile, vinylpyrrolidone.

The proportion of these polymerizable monomers to be used is not particularly limited, but is preferably 5 parts or more and 200 parts or less based on 100 parts by weight of the total amount of the unsaturated isocyanate and the unsaturated silane compound.

This does not mean that using more than 200 parts cannot be used, but there is a tendency for the viscosity to decrease and the effectiveness to decrease somewhat.

Moreover, if it is less than 5 parts, there is little point in adding it.

Furthermore, it may be useful to dissolve and use a polymer soluble in the polymerizable monomer in combination with the polymerizable monomer to improve adhesion.

For example, a coating made by mixing an appropriate amount of unsaturated incyanate with so-called acrylic syrup, which is made by dissolving polymethyl methacrylate in methyl methacrylate, and curing it with a radical-generating curing agent, adheres extremely well to wet concrete surfaces.

The polymer used here is not particularly limited as long as it is soluble in the monomer; examples thereof include polymethyl methacrylate, polystyrene, polyvinyl acetate, butyl acrylate, and acrylonitrile. copolymer rubber, chlorosulfonated polyethylene, thermoplastic amorphous polyester, ethylene-vinyl acetate copolymer, and the like.

After applying the primer according to the invention to the concrete,
Furthermore, it can be overcoated with a desired paint, and has good adhesion with the topcoat.

It goes without saying that the primer according to the present invention can also be used in combination with fillers, colorants, reinforcing materials, etc., if necessary.

〔Example〕

Next, examples will be shown below to help understand the present invention.

1. Synthesis of unsaturated isocyanate (B1) In a 11 separable flask equipped with a stirrer, a reflux condenser, a thermometer with a gas introduction tube, and a dropping funnel, 2.4-
) 174 g of lylene diisocyanate and 0.05 g of methylbarabenzoquinone are charged, and 144 g of 2-hydroxypropyl methacrylate is added dropwise in dry air over a period of 30 minutes at a temperature of 60°C.

After the completion of the dropwise addition, the reaction was carried out at the same temperature for 1 hour, and then 1.2 g of dibutyltin dilaurate was added, and the reaction was further carried out for 1 hour to obtain unsaturated isocyanate (B1) in the form of a pale yellow liquid. As a result of infrared analysis, approximately 60 (%) of isocyanate groups
It was determined that there was a reaction.

Production Example 2 Synthesis of unsaturated isocyaner (B2) Methyl methacrylate 82 was added to a 11 separable flask equipped with a stirrer, a reflux condenser, a thermometer with a gas introduction tube, and a dropping funnel.
g, 174 g of isophorone diisocyanate, and 0.059 g of methylbarabenzoquinone were prepared, and 144 g of 2-hydroxyethyl methacrylate was added in dry air at a temperature of 60°C.
It takes 0 minutes to drip.

After the dropwise addition was completed, the reaction was carried out at the same temperature for 1 hour, and then 1.2 g of dibutyltin dilaurate was added, and the reaction was further carried out for 1 hour to obtain unsaturated incyanato (B 2 ) (methyl methacrylate solution) in the form of a pale yellow liquid.

As a result of infrared analysis, it was determined that approximately 60 (%) of the isocyanate groups had reacted.

Chestnut, 3IJ1 30cm x 30c soaked in water at room temperature for 3 days
A concrete plate measuring 5 cm x 5 cm was lifted out of the water for 30 minutes.
After leaving it at room temperature for several minutes, wipe the surface with a cotton cloth.

Immediately on this surface, a mixture of 100 parts by weight of gamma-methacryloxypropyltrimethoxysilane, 5 parts by weight of benzoyl peroxide (50% powder), and 0.3 parts by weight of dimethypara-toluidine was added at 50 g/l11
It was painted so that the color was 2.2, and the device was installed at night.

Furthermore, as a coating resin containing glass flakes, lipoxy flake compound FC-80 manufactured by Showa Kobunshi Co., Ltd.
to 100 parts, hardening agent #328E manufactured by Kayaku Nouri Co., Ltd.
1.5 parts of cobalt naphthenate and 0.5 parts of cobalt naphthenate were added, and the coating was coated to a coating thickness of 500 μm and cured.

In the tensile adhesion test using El3meter, 25 to 30
The adhesive strength was 1.5 kg, and all 5 measurement points had concrete fractures at a depth of 1 to 2 zi+.

Example 2 A coating test was conducted in the same manner as in Example 1 using the following mixture.

Gamma-methacryloxypropyltrimethoxysilane 70 parts by weight Methyl methacrylate 30 parts by weight Benzoyl peroxide (5 parts by weight)
0% powder) 5 parts by weight dimethylaniline
A tensile adhesion test using a 0.3 parts by weight elcometer showed 35 to 45 kg (range of 5 measurements), all of which appeared to have penetrated to a depth of 2 to 3 x m from the concrete surface and hardened. showed that.

and 1-1 A mixture of gamma-methacryloxypropyltrimethoxysilane and dimethyl para-toluidine in the formulation of Example 1 except for benzoyl peroxide was applied in the same manner, and then a flake compound was applied. The adhesive strength measured by Elcometer was 5 to 20 mm, which was a little low, but all of the concrete had fractures of 0.5 to 1 x m.

Example 4 A coating test was conducted in the same manner as in Example 1 using the following mixture. However, the thickness of the brush coating was 70 g/2 gulls.

Vinylmethoxysilane 50 parts by weight Benzoyl peroxide (50% powder) 3 parts by weight Dimethylaniline
A tensile adhesion test using a 0.,2 parts by weight Elcometer showed 35-45 kg (5 measurement ranges), all of which were 1-45 kg from the concrete surface.
The figure shows the state of the fracture after it had penetrated to a depth of 2 liters and hardened.

Example 5 A coating test was conducted in the same manner as in Example 1 using the following mixture. However, the thickness of the brush coating was 70 g/2.

Vinyl ethoxysilane 50 parts by weight Unsaturated isocyanate compound (B 2) (Production example 2) (methyl methacrylate solution) 50 parts by weight Benzoyl peroxide (5 parts by weight)
0% powder) 3 parts by weight dimethylaniline
A tensile adhesion test using a 0.2 parts by weight elcometer showed 35 to 45 kg (range of 5 measurements), and all of the concrete had broken into the concrete at a depth of 1 to 21 meters and hardened. showed that.

No. 11 - Lambda sizing (cement-asbestos building material) manufactured by Niji Showa Denko Kenzai Co., Ltd. was cut into 30 cm pieces and immersed in water at room temperature for 3 days.

Immediately after pulling up, the surface was wiped with a dry cloth, and the following formulation was immediately applied at a concentration of 100 g/m'', and left to cure day and night.

Gamma-methacryloxypropyl tris(beta-methoxyethoxy)silane 50 parts by weight Acrylic syrup containing approximately 32% polymethyl methacrylate 50 parts by weight (polymethyl methacrylate 32% methyl methacrylate monomer 68%) Benzoyl peroxide
5 parts by weight dimethylaniline 0.3 parts by weight In a tensile adhesion test using an ercometer using epoxy resin as an adhesive, the measured values at 5 points were all 25 to 2.
As shown above, all materials were broken.

Example 7 A coating test was conducted in the same manner as in Example 1 using the following mixture. However, the thickness of brush coating is 70g/I+12
And so.

Gamma-methacryloxypropyltrimethoxysilane 50 parts by weight Isocyanate ethyl methacrylate 50 parts by weight Benzoyl peroxide (50% powder) 3 parts by weight Dimethylaniline 0.2 parts by weight In a tensile adhesion test using an Elcometer, 25 to 35 Ly (
5 measured value ranges), and all of them showed the state of fracture that had penetrated to a depth of 1 to 2 mm from the concrete surface and hardened.

〔Effect of the invention〕

The primer according to the present invention is mainly composed of a specific unsaturated silane compound alone and, if necessary, an unsaturated isocyanate compound, and also contains a polymerizable monomer, so it can be used for concrete that has pores or cracks, It penetrates well into concrete whose surface has deteriorated due to changes and hardens.
It also adheres well to wet concrete surfaces, forming a coating that prevents moisture and gas from entering. Moreover, since this primer has good adhesion with topcoat paint, a desired topcoat can be applied thereon, which is useful for preventing deterioration and fading of concrete structures and maintaining the aesthetic appearance.

Claims (3)

[Claims] (1) General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, R^1 is hydrogen or methyl group, M is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, and R^2 has 2 carbon atoms ~4 alkylene group, n is 0 or 1, and X has 1 carbon number
-4 alkoxy group] A primer mainly composed of an unsaturated silane compound represented by the following. (2) (A) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼ [However, R^1 is hydrogen or methyl group, M is ▲There are mathematical formulas, chemical formulas, tables, etc.▼, and R^2 is Alkylene group having 2 to 4 carbon atoms, n is 0 or 1, and X is 1 carbon number
-4 alkoxy group] and (B) an unsaturated isocyanate having a (meth)acryloyl group and an isocyanate group in the molecule, and optionally a polymerizable monomer. , a primer containing a polymer and a curing agent that are dissolved in the polymerizable monomer. (3) The primer according to claim 2, which contains an organic peroxide as a curing agent.