JPH07156115A - Coating composition for colored concrete and form material - Google Patents

Abstract

PURPOSE:To efficiently and economically provide colored concrete like natural stone which solves conventional technical problems concerning colored concrete. CONSTITUTION:A composition comprises a binder, a coloring agent, and a liquid medium. The binder is stable in an acid and/or neutral atmosphere but easily soluble in an alkaline atmosphere. A colored film layer is formed in advance on the surface of a form to obtain a coating composition for colored concrete to produce a colored concrete structure by casting concrete into the form and a form material for colored concrete molding coated with the coating composition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paint composition for colored concrete using a mold and a colored mold material for molding concrete.

[0002]

2. Description of the Related Art A concrete molded product (hereinafter simply referred to as concrete) has been used in many structures as a structural material having excellent strength and durability, but since the appearance of concrete is gray, this gray Since it is inconsistent with the surrounding environment, the demand for colored concrete as a landscape material is increasing in recent years. A wide variety of concrete coloring materials are required, from relatively small ones such as color blocks and flat plates to large-scale civil engineering works such as seawalls and levee walls.

Conventionally, as a method for coloring concrete, a method using a color cement, a method using a colorant such as a pigment, a method using a colored aggregate, etc. are known.
Further, as a method of coloring the surface of concrete, a method of applying various finishing coating materials to the surface has also been used.

[0004]

However, in the method of coloring the concrete itself, a uniform coloring layer can be obtained on the inside, but the so-called white flower phenomenon occurs on the surface, and the state of the cement or cement used. Since it depends on the type of aggregate, the amount of kneading water, the construction conditions, etc., there is a problem that the appearance of the concrete surface is impaired. Further, as the material of the mold, there are wood, metal, plastic, rubber, etc., but there is poor curing due to soluble alkali in wood,
Due to dirt due to metal rust, defective release from the mold, etc.
It impairs the appearance of the concrete surface and makes it difficult to reuse the formwork.

For this reason, the surface of the concrete after mold release may be finished by polishing, washing, tapping, sand plasting or the like to be commercialized, but such surface treatment causes a significant cost increase. It cannot be avoided. On the other hand, the method of painting the surface of concrete with a paint is also a long-established method, but it is inferior to the natural texture compared to the coloring of the concrete itself, and also the adhesion to the concrete surface and the coating film There is a problem that weather resistance deterioration becomes a problem, and further, if the coating layer on the surface is damaged by some physical action due to surface coating, the uncolored concrete surface layer is exposed and the appearance is impaired.

Therefore, as the performance of the colored concrete,
Artificial structures such as buildings, roads, and bridges are required to be in harmony with the environment surrounding colored concrete, such as greenery, waterfronts, topography, and cities. Therefore, an object of the present invention is to solve the problems of the prior art regarding colored concrete, and to provide colored concrete close to natural stone efficiently and economically.

[0007]

The above object can be achieved by the present invention described below. That is, the present invention comprises a binder, a colorant and a liquid medium, wherein the binder is acidic and / or
Or, it has a property of being stable in a neutral atmosphere and easily dissolved in an alkaline atmosphere.A colored coating layer is formed in advance on the surface of the mold, and concrete is poured into this mold to color it. A paint composition for colored concrete for producing a concrete structure, and a colored mold material for molding concrete, which is obtained by applying the paint composition.

[0008]

[Function] In the concrete formwork execution method, when the concrete is placed on the formwork, the surface of the formwork is colored in advance, which is stable in an acidic and / or neutral atmosphere and dissolves in water in an alkaline atmosphere. A colored concrete structure having a surface texture similar to that of natural stone can be easily provided by forming a coating film, placing concrete in the mold, curing and releasing the mold.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail with reference to the preferred embodiments. The formwork used in the present invention may be any form made of wood, metal, plastic, rubber or concrete.

According to the present invention, a colored coating layer is formed on the surface of the mold in advance with a coating composition comprising a binder having a property of being stable in an acidic and / or neutral atmosphere and being soluble in an alkaline atmosphere. When concrete is poured into the frame, the colored coating layer is dissolved by the alkali of the water-soluble substance in the cement, the coloring component penetrates into the surface of the uncured concrete, and the surface layer of the concrete structure is colored. It prevents the adhesion of concrete and improves the releasability after curing.

The binder used in the coating composition of the present invention may be any binder as long as the coating film thus obtained is stable in an acidic and / or neutral atmosphere and easily dissolved in water when it is alkaline. Examples include vinyl acetate-based, acrylic-based, urethane-based, polyester-based resin emulsions or water-soluble resins, and mixed systems thereof.

As the concrete to be poured, uncolored concrete may be used, but it is preferable to use colored concrete having a color similar to that of the colored coating film to prevent damage or breakage of the concrete after coloring or damage. It is possible to obtain a colored concrete structure in which the concrete surface does not change even when the surface deteriorates due to long-term exposure.

As the coloring material, any of pigments, dyes and the like can be used, but a coloring material having alkali resistance and good affinity with cement is suitable, and general inorganic pigments and organic pigments can be used. In addition to dyes and pigments, special functional powders such as fluorescent pigments and infrared absorbing pigments, and particle size 0.5 to 3 such as colored silica sand.
It is also possible to change the function and finish of the concrete surface by using an aggregate of about mm.

[0014]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples. In the text, parts and% are based on weight. Example 1 Dark brown concrete [Paint formulation 1] Pigment (Bengara, iron black) 8 parts Binder (vinyl acetate emulsion) 60 parts Water 32 parts

The paint of Formulation 1 was applied to the surface of a mold made of synthetic resin by spraying so as to have a coating thickness of 50 μm, and naturally dried for 12 to 24 hours. [Concrete mix 1] Portland cement 20 parts Pigment (Bengara, iron black) 2 parts Aggregate 60 parts Water 18 parts The above concrete mix 1 is cast into a synthetic resin mold on which the colored coating film is formed, After curing for 3 days, the mold was removed and the surface and interior were colored dark brown.

Comparative Example 1 Concrete mix 1 was cast into a synthetic resin mold having no coating layer, cured for 3 days, and then the mold was removed.
Although the inside was colored dark brown, the surface was whitish and non-uniform. Further, part of the concrete adhered to the mold at the time of mold release, the surface of the concrete was rough, and the mold could not be reused.

Example 2 Green Concrete [Coating Formulation 2] Pigment (Dai Pyroxide Color Green # 9310) 20 parts Binder (acrylic water-soluble resin) 50 parts Water 30 parts Coating composition 2 is used for the surface of a metal mold. Was sprayed to a coating thickness of 30 μm and naturally dried for 12 to 24 hours.

[Concrete Mixture 2] Portland Cement 20 parts Pigment (Dai Pyroxide Color Green # 9310) 4 parts Aggregate 60 parts Water 16 parts Concrete mix 2 is cast on the metal formwork on which the colored coating film is formed. After setting and curing for 3 days, the mold was removed, and both the surface and the interior were colored green.

Comparative Example 2 In the paint formulation 2 of Example 2, a paint using an acrylic emulsion resin that forms a stable film in an alkaline atmosphere as a binder is spray-applied to the surface of a metal mold. Apply to 30 μm and air dry for 12 to 24 hours. After concrete mix 2 was cast into this product and cured for 3 days, the mold was removed. The coating film adhered to the mold and the concrete surface was not colored.

Comparative Example 3 A commercially available green exterior cement-based spraying material was sprayed onto the surface of uncolored concrete to prepare colored concrete. When each of the concrete structures of Example 2 and Comparative Example 2 was exposed outdoors for one year, the appearance of the concrete structure of Example 2 showed almost no change, whereas the concrete structure of Comparative Example 2 was not changed. The surface change was remarkable and the surface texture was inferior.

[0021]

Since the coating film formed from the coating composition of the present invention is essentially completely dissolved by the alkaline substance in the concrete milk, the surface layer after hardening of the concrete is a so-called "polymer cement mixed concrete layer". "
In addition to the fact that the strength is much higher than that of a normal concrete surface, the occurrence of efflorescence (white flower phenomenon) due to exposure can be suppressed.
Since the coating film obtained by the coating composition of the present invention does not dissolve in an acidic and / or neutral atmosphere, the coating film applied to the formwork should be washed away by rain during construction outdoors. There is no.

Claims (2)

[Claims] 1. A formwork in advance, comprising a binder, a colorant and a liquid medium, wherein the binder has a property of being stable in an acidic and / or neutral atmosphere and easily dissolved in an alkaline atmosphere. A coating composition for a colored concrete for forming a colored coating film layer on the surface of, and casting concrete on the mold to produce a colored concrete structure. 2. A formwork material for molding colored concrete, which is coated with the coating composition according to claim 1.