JPH09118574A - Cementitious base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of external appearance due to the soiling in outdoor by forming a protective layer without impairing the feeling of concrete placed as it is. SOLUTION: A cementitious base material has coating films formed of a first coating material, a middle coating material and a finish coating material, the contact angle of the coating film formed of the finish coating material to water is <90 deg. and the contact angle thereof to a liquid paraffin is >=30 deg.. The middle coating material preferably contains a pigment having refractive index of 1.4-1.7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for finish-coating a cement-based substrate.

[0002]

2. Description of the Related Art Cement-based materials such as concrete, asbestos slate, mortar, ALC (lightweight cellular concrete), GRC (glass fiber reinforced concrete), CFRC (carbon fiber reinforced concrete), calcium silicate material, gypsum and slag material. The materials are widely used in construction and building materials, and solution-type acrylic resin-based, acrylic urethane resin-based, and fluororesin-based paints have been applied for the purpose of imparting beauty to these materials and improving their durability. It was

However, the coating film obtained by applying such a paint generally changes the appearance of the cement-based base material in most cases, and it is difficult to realize, for example, "a feeling of concrete being exposed". In addition, even if a transparent finishing material is used, it is customary that a wet skin color or unevenness occurs. Further, the surface of the coating film used as the exterior material was apt to be conspicuously stained by outdoor contaminants. In particular, when the contaminants were streaky stains formed by the flow of rainwater, the appearance of the building was significantly impaired.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art by using a specific undercoating material, intermediate coating material and overcoating material.

[0005]

The present invention is a cement-based base material having a coating film formed by an undercoat material, an intermediate coating material and an overcoat material, and the contact angle of the coating film formed by the overcoat material with water. Is less than 90 degrees, and the contact angle with liquid paraffin is 30 degrees or more.

In the present invention, the cement-based base material means a building or building material on which the coating film of the present invention is formed, the material of which is the above-mentioned cement-based material.

On the cement-based substrate in the present invention, there are three layers of a coating film formed by an undercoat material, an intermediate coating material and an overcoat material in this order from the cement-based substrate side.

The undercoating material is transparent and functions as a primer with a small coating amount to ensure the adhesion between the cement-based base material and the intermediate coating material, as well as water, acid, alkali, solvent, etc. It is selected from those having a function of protecting the cement-based base material against chemicals and corrosive gases.

The intermediate coating material is generally selected from those having a function of correcting uneven suction which is likely to occur when a small amount of the above-mentioned undercoat material is applied to a cement-based base material having a non-uniform surface.

[0010] The top coat material, together with the intermediate coat material, is generally used to protect the cement-based base material against ultraviolet rays, water, chemicals such as acid / alkali / solvent, corrosive gas, etc. It is selected from those having the function of an overcoat material.

As long as the undercoat material, the middle coat material and the top coat material have the above-mentioned functions required for each, the main components of the undercoat material, the middle coat material and the top coat material may be common.

The main component of the undercoat material is vinyl resin,
A coating material containing an acrylic resin, an epoxy resin, a polyurethane resin, a chlorinated polyolefin resin, a silicone resin, a silicon compound or a condensate thereof, a polybutadiene resin, a fluororesin or the like as a main component is preferable. In particular, a silicon compound or a partial condensate thereof that easily achieves adhesion with a small amount of coating, a silicon-based paint containing a silicone resin as a main component, or an epoxy resin-based paint containing an epoxy resin as a main component is particularly preferable.

As the epoxy resin, a curing agent such as amines or polyamide resin may be used together, or a modified epoxy resin in which an acrylic monomer or amine is bonded to epoxy groups at both ends may be used. As the silicone resin, a modified silicone resin such as alkyd-modified, acrylic-modified or epoxy-modified can be used.

The silicon compound in the present invention means a compound having a hydrolyzable silyl group in which a hydrolyzable group such as an alkoxy group, an isocyanate group or a halogen atom is directly bonded to a silicon atom. Only the above hydrolyzable group may be bonded to the silicon atom of this silicon compound,
In addition to the hydrolyzable group, a non-hydrolyzable group such as an alkyl group, an aminoalkyl group and an epoxyalkyl group may be bonded.

Specific examples of the silicon compound include methyltrimethoxysilane, methyltriethoxysilane, methyltriisobutoxysilane, methyltributoxysilane, tetramethoxysilane, tetraethoxysilane, tetraisobutoxysilane, tetrabutoxysilane and methyltributoxysilane. −
sec-octyloxysilane, methyltriphenoxysilane, tetraphenoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, methyltri (acryloyloxyethoxy) silane, methyltri (glycidyloxy) silane, octyltriethoxysilane, lauryltriethoxysilane, Stearyl trimethoxysilane, stearyl triethoxysilane, etc. are mentioned.

Commercially available water absorption inhibitors containing these silicon compounds or partial condensates thereof, such as Aron Watershut [Toagosei Co., Ltd.], Excella [Kansai Paint Co.], Aquaseal [Sumitomo Seika] The same can be used as an undercoating material, such as [made by the company] and Dickguard [made by Dainippon Ink and Chemicals].

Further, it is preferable to coat the undercoating material to such an extent that the appearance of the cement-based base material is not impaired. Further, it is preferable to apply the coating to such an extent that it has a function of securing adhesion with an intermediate coating material, which is a purpose of a normal undercoating material, and protecting a substrate. Specifically, JIS-A-6910
The water permeability after 24 hours in the water permeability test of 0.15
It is preferable to apply the paint so that the amount becomes 2.00 g. Further, in consideration of the appearance, it is preferable that the film thickness is about 10 μm or less.

The main component of the intermediate coating material is vinyl resin,
A coating material containing an acrylic resin, an epoxy resin, a polyurethane resin, a chlorinated polyolefin resin, a silicone resin, a silicon compound or a condensate thereof, a polybutadiene resin, a fluororesin or the like as a main component is preferable. Considering durability, a fluororesin-based coating material containing a fluororesin as a main component or a polyurethane resin-based coating material containing a polyurethane resin as a main component is more preferable. As the polyurethane resin, a resin whose polyol component is an acrylic polyol or a polyester polyol can be used.

As the fluororesin, a wide range of fluororesins for paints can be adopted. Preferred is a fluorocopolymer obtained by copolymerizing a fluoroolefin and another monomer copolymerizable therewith.

Examples of such fluoroolefins include tetrafluoroethylene, chlorotrifluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride and the like, and perhaloolefins such as tetrafluoroethylene and chlorotrifluoroethylene are preferable.

As the other monomer copolymerizable with the fluoroolefin, an ethylenically unsaturated compound is preferably used. Examples of the ethylenically unsaturated compound include vinyl ether, allyl ether, carboxylic acid vinyl ester, carboxylic acid allyl ester, and olefin.

As the vinyl ether, cycloalkyl vinyl ether such as cyclohexyl vinyl ether, ethyl vinyl ether, nonyl vinyl ether, 2-ethylhexyl vinyl ether, hexyl vinyl ether,
Examples thereof include alkyl vinyl ethers such as n-butyl vinyl ether and t-butyl vinyl ether. Examples of the allyl ether include alkyl allyl ethers such as ethyl allyl ether and hexyl allyl ether.

Examples of the carboxylic acid which is a raw material for the carboxylic acid vinyl ester and the carboxylic acid allyl ester include acetic acid, butyric acid, pivalic acid and benzoic acid. As the vinyl ester of a carboxylic acid having a branched alkyl group, commercially available Veova-9 and -10 [both manufactured by Shell Chemical Co.] can be used. Examples of olefins include ethylene and isobutylene.

As the other monomer copolymerizable with the above-mentioned fluoroolefin, only one kind may be used, or two kinds such as two kinds in vinyl ether or two kinds of vinyl ether and vinyl carboxylate may be used. The above monomers can be used in combination. The fluorine-based copolymer may be a copolymer having no curing reactive site, but is preferably a copolymer having a curing reactive site.

The curing reactive site may be one that reacts with a curing agent to form a crosslink. The curing reactive site can be appropriately selected depending on the combination with a curing agent, but typical examples thereof include a hydroxyl group, a carboxyl group, a glycidyl group, an epoxy group, an amino group and the like. Examples of the method of introducing such a curing reactive site include a method of copolymerizing a monomer having a curing reactive site during a copolymerization reaction.

It is also possible to introduce a curing reactive site by post-reaction after polymerization. Examples of this method include the following methods (1) to (4).

(1) A method of introducing a hydroxyl group by saponifying a polymer obtained by copolymerizing a carboxylic acid vinyl ester. (2) A method of introducing a carboxyl group by reacting a polymer having a hydroxy group with a polyvalent carboxylic acid or an anhydride thereof. (3) A method of reacting an isocyanate alkoxysilane with a polymer having a hydroxy group to introduce a hydrolyzable silyl group. (4) A method of introducing an isocyanate group by reacting a polyvalent isocyanate compound with a polymer having a hydroxy group.

Examples of such a monomer having a curing reactive site include hydroxyalkyl vinyl ether such as hydroxyethyl vinyl ether and 4-hydroxybutyl vinyl ether, and cycloalkyl in the hydroxyalkyl portion of hydroxyalkyl vinyl ether such as cyclohexanedimethanol monovinyl ether. Group or cycloalkylene group-containing monomer, 2-hydroxyethyl allyl ether or other hydroxyalkyl allyl ether, crotonic acid, 10-undecenoic acid or other carboxylic acid group-containing monomer, triethoxyvinylsilane or other hydrolyzable Monomers having silyl groups, glycidyl vinyl ether, glycidyl allyl ether, monomers having epoxy groups such as β-methyl glycidyl vinyl ether,
Examples thereof include amino group-containing monomers such as aminopropyl vinyl ether and aminopropyl allyl ether.

The proportion of the polymerized units based on the fluoroolefin contained in all the polymerized units of the fluorine-based copolymer is usually 20 to 80 mol%, preferably 40 to 60 mol%.
It is. The ratio of the polymerized units having a curing reactive site contained in all the polymerized units of the fluorine-based copolymer is usually 0.1 to 10.
It is 50 mol%, preferably 1 to 30 mol%.
The number of curing reactive sites such as a hydroxyl group and a carboxyl group in the copolymer having a curing reactive site is 1 to 15 relative to the resin solid content in terms of chemical reaction equivalent of potassium hydroxide.
Those corresponding to 0 mg / g are preferable, and 10 to 130 m
g / g is particularly preferred.

A coating material containing a fluororesin as a main component can be prepared by combining the above-mentioned fluororesin with a curing agent. As such a curing agent, those known as coating curing agents can be used. Specifically, aminoplast,
Examples include melamine-based curing agents such as urea resins, polyvalent isocyanate-based curing agents, and block polyvalent isocyanate-based curing agents. Further, a polyvalent isocyanate curing agent that does not require high temperature baking and can be installed on site is preferably adopted. In particular, a non-yellowing type polyvalent isocyanate curing agent is preferably used.

In order to prevent a change in appearance due to wet skin after coating, it is effective to add a pigment having a refractive index of 1.4 to 1.7 to the intermediate coating material.

Examples of pigments having a refractive index of 1.4 to 1.7 include asbestine, calcium carbonate, precipitated calcium carbonate,
Clay, kaolin, porcelain clay, aluminum silicate, diatomaceous earth, white carbon, silica white, hydrous fine powder silicic acid, bentonite, talc talc powder, hydrous magnesium silicate,
Precipitating magnesium carbonate, basic magnesium carbonate, barite powder, barium sulfate, precipitating barium sulfate, barium carbonate and the like can be mentioned. Considering durability, kaolin, porcelain clay, diatomaceous earth, white carbon, silica white, hydrous fine powder silicic acid, precipitated barium sulfate and the like are preferable.

It is also possible to adjust the appearance by adding a small amount of a pigment having a refractive index outside the above range to the extent that transparency is not impaired. Examples of such a pigment include white pigments such as titanium oxide and carbon black. Black pigment, red pigment such as red iron oxide,
Yellow pigments such as loess, and green pigments and blue pigments can be used if necessary.

The main component of the overcoat material is vinyl resin,
A paint containing an acrylic resin, an epoxy resin, a polyurethane resin, a chlorinated polyolefin resin, a silicone resin, a polybutadiene resin, a fluororesin or the like as a main component can be used. Considering durability, a fluororesin-based coating material containing a fluororesin as a main component or a polyurethane resin-based coating material containing a polyurethane resin as a main component is preferable.

Further, it is important that the contact angle of the coating film formed of the overcoat material with water is less than 90 degrees and the contact angle with paraffin is 30 degrees or more. In order to form a coating film having such properties, a general formula Si (OR) ₄ (wherein R is the same or different and represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) in the overcoat material. .) Or a partial condensate thereof (hereinafter,
It is preferable to incorporate compound A) including a partial condensate. If the number of carbon atoms of R in the general formula exceeds 5, the effect of stain resistance decreases. An alkyl group having 1 or 2 carbon atoms is particularly preferable because it has an effect of excellent stain resistance. Preferred examples of the compound represented by the general formula Si (OR) ₄ are:
Tetramethoxysilane and tetraethoxysilane.

The silica content of the compound A is 10
The silica content in 0% hydrolyzed and condensed is 20 to 6
It is preferred to use 0% by weight. If the silica content is too low, the effect of stain resistance is reduced, and if it is too high, storage stability is impaired, which is not preferable.

The compounding ratio of the compound A is preferably 0.5 to 60 parts by weight with respect to 100 parts by weight of the coating resin which is the main component of the overcoat material. It is more preferably 2 to 30 parts by weight because of poor coating properties such as sagging, leveling and the like.

Acid catalysts such as hydrochloric acid and p-toluenesulfonic acid, or metal chelate compounds such as aluminum chelates, which are conventionally known, can be used as an accelerator for promoting the dealkoxy group reaction of compound A and the reticulation of molecules. .

The compound A is compounded in the top coat material by using a method of blending the top coat material into the top coat material immediately before coating, a method of premixing with the coating resin which is the main component of the top coat material, and a curing agent. In this case, any method of premixing with the curing agent may be used. In the case of the method of mixing in advance, it is preferable that the accelerator for promoting the reticulation of the compound A is blended immediately before the coating of the overcoat material.

Generally, the overcoat material is used as a substantially transparent coating material, but it is also possible to add a pigment as necessary to adjust the appearance. As such a pigment, asbestine,
Calcium carbonate, precipitated calcium carbonate, clay, kaolin, porcelain clay, aluminum silicate, diatomaceous earth, white carbon, silica white, hydrous fine powder silicic acid, bentonite,
Talc talc powder, hydrous magnesium silicate, precipitated magnesium carbonate, basic magnesium carbonate, barite powder, barium sulfate, precipitated barium sulfate, barium carbonate, white pigments such as titanium oxide, black pigments such as carbon black, and red iron oxide There are red pigments, yellow pigments such as ocher, and other green pigments and blue pigments.

Further, since the finishing method of the present invention is often applied on site, the synthetic resin coating for the intermediate coating material and the top coating material does not require high temperature baking and is a two-component curing agent which gives an excellent finished appearance. Mold paints are preferred. Polyurethane-based paints, fluororesin paints, and the like are known as such two-component curable paints. Particularly, a fluororesin coating having excellent weather resistance is preferable.

Further, when an ultraviolet absorber is added to the top coat material, the durability is further improved. As such an ultraviolet absorber, a hindered amine type, a benzophenone type, a benzotriazole type or the like can be used.

[0043]

【Example】

"Example 1" An undercoating material containing aqua seal [Sumitomo Seika Chemical Co., Ltd., alkyltrialkoxysilane partial condensate] as a main component was spray-coated on a dry-cured concrete ordinary pavement flat plate. Then, on the coated surface, Lumiflon LF-200 [Asahi Glass Co., Ltd., hydroxyl group-containing fluoroolefin copolymer (hydroxyl value: 52 mgKOH / g) 6
20.0 to 30.0 g of an organic solvent solution containing 0% by weight.
g of precipitated barium sulfate is mixed and dispersed in a ball mill together with a dispersant and an antifoaming agent, and hardener Coronate HX [Nippon Polyurethane, non-yellowing type isocyanate hardener]
An intermediate coating material obtained by adding 3.40 g and diluting to a spray viscosity was applied.

Further, on the coated surface, Lumiflon LF-
Aluminum chelate A [Aluminum chelate compound manufactured by Kawaken Fine Chemicals Co., Ltd.] was added to 57.0 g of 200 0.3
6.4g of Coronate HX as a curing agent
0 g was added, and 6.80 g of an ethyl silicate condensate having a silica content of 40% by weight was added and mixed, and the top coat material obtained was coated to prepare a test body.

"Examples 2 to 7, Comparative Examples 1 to 3" Various coating materials were prepared as the undercoating material, the intermediate coating material, and the overcoating material, and the performance evaluation test results of the test pieces prepared in the same manner as in Example 1 are shown. Shown in 1. In addition, 9.0 g of finely powdered silicic acid was added as a matting agent to 5.70 g of LF-200 in the topcoat material of Example 5 and mixed, and then the same adjustment as in Example 1 was performed. In addition, the undercoat material contains methyltrimethoxysilane partial condensate (hereinafter abbreviated as methyltrimethoxysilane) as a main component.

In Table 1, Acridic BU-955 is a polyurethane resin manufactured by Dainippon Ink and Chemicals, Inc. whose polyol component is acrylic polyol. What is the appearance of the test piece?
The appearance was good when the texture of the concrete pavement was maintained. The outdoor exposure test was performed under the condition that the test surface was directed to the upper part of the south and the angle with the horizontal plane was 30 degrees. The degree of contamination was visually compared on the surface of the coating film, and was marked when it was markedly contaminated.

[0047]

[Table 1]

[0048]

INDUSTRIAL APPLICABILITY The cement-based base material of the present invention can form a protective layer having a good antifouling property without impairing the texture of the cement-based base material.

Claims (4)

[Claims] 1. A cement-based substrate having a coating film formed of an undercoating material, an intermediate coating material and an overcoating material, wherein the coating film formed of the overcoating material has a contact angle with water of less than 90 degrees, and A cement-based base material having a contact angle with liquid paraffin of 30 degrees or more. 2. The cement-based base material according to claim 1, wherein the intermediate coating material contains a pigment having a refractive index of 1.4 to 1.7. 3. The topcoat material is of the general formula Si (OR) ₄ (wherein R
Are the same or different and each is a hydrogen atom or has 1 to 5 carbon atoms.
Represents an alkyl group. The cement-based base material according to claim 1, which contains a compound represented by the formula (1) or a partial condensate thereof. 4. The cement-based base material according to claim 1, wherein the intermediate coating material and the top coating material are paints containing a fluororesin as a main component.