JP2002211988A - Coating composition for calcium-based inorganic base material and method of producing colored calcium-based inorganic base material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition with which a colored coated film containing an inorganic pigment can be formed on the surface of a calcium-based inorganic base material such as concrete, and which has excellent dispersibility of the pigment and exhibits time stability and further with which a coated film having high hardness, excellent antifouling property, weatherability or the like can be formed. SOLUTION: The composition is a coating composition useful for coating the calcium-based inorganic base material and contains a water soluble alkali silicate compound and pigment. The amount of the water soluble alkali silicate compound contained in the composition is 10 to 50 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a water-based coating composition for coloring a calcium-based inorganic substrate such as a concrete substrate, and for strengthening the colored surface and improving weather resistance. The present invention relates to a method for preparing a colored substrate using the composition, and a colored substrate obtained by the method.

[0002]

2. Description of the Related Art Attempts have been made to color calcium-based inorganic products used for building materials, buildings, and the like, for example, products made of concrete, cement, gypsum, stone, and the like. In general, water glass (aqueous solution of a water-soluble alkali silicate compound) is used to protect and strengthen the surface of such an inorganic substrate.
Is applied to form a cured film. For example, it is considered that a coloring paint can be obtained by adding an inorganic pigment to the water glass.

[0003] However, even when such a paint is applied on an inorganic substrate such as concrete, generally, only the liquid component permeates into the substrate, and the pigment does not penetrate into the substrate, and the surface thereof has a thickness of several microns to several tens. A micron colored layer is formed on the substrate. Therefore, the formed colored coating film has poor durability, and the background is easily exposed by friction or the like. In order to prevent this, it is necessary to apply a thick paint to form a thick layer. Further, since a coating material in which about 1 to 5% of a pigment is dispersed in a liquid is applied, it is difficult to apply the coating uniformly, and color unevenness tends to occur. If the base material itself is a material that has a high degree of porosity and absorbs water well,
The pigment cannot be fixed and peels off easily from the surface.

[0004] Further, since the pigments in such paints are liable to settle, they need to be frequently stirred during coating. When the paint is stored, there is also a disadvantage that the pigment in the paint sediments and the pigment particles adhere to each other and are difficult to redisperse.

[0005] As a technique for protecting the surface of a calcium-based inorganic substrate, Japanese Patent Application Laid-Open No. 9-110558 discloses a treating agent containing a water-soluble silicate compound and at least one of an organic acid and an organic acid salt. Is disclosed. This treating agent contains an organic or inorganic pigment as necessary, and can obtain a colored substrate. The above-mentioned organic acid and organic acid salt are contained in order to enhance the permeability to the surface of a concrete substrate or the like. However, since such an organic acid component is contained, this treating agent has a poor storage stability, and has a drawback that even if a coating film is formed on the surface with the treating agent, the stain resistance and weather resistance are poor. Since the penetration of the liquid component of the treating agent is increased by containing the organic acid, when the pigment particles are large enough not to enter the pores of the concrete base material, the pigment is added to the surface portion. Only remain. As a result, the pigment cannot be fixed on the substrate surface.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to easily color a calcium-based inorganic substrate such as a concrete substrate. An object of the present invention is to provide a coating composition having excellent dispersibility and preservability. Another object of the present invention is to provide a coloring coating composition having the above excellent properties, a reinforced surface, excellent weather resistance, and capable of forming a uniform colored film. Still another object of the present invention relates to a method for producing the composition and a method for producing a colored calcium-based inorganic substrate using the composition.

[0007]

The first coating composition for a calcium-based inorganic substrate according to the present invention contains a water-soluble alkali silicate compound and a pigment, and the water-soluble alkali silicate compound is contained in an amount of 10 to 50% by weight. It is contained in the ratio of.

In a preferred embodiment, the water-soluble alkali silicate compound contains M ₂ O (M is an alkali metal) and SiO ₂ as components, and the M ₂ O and SiO ₂
The ratio of ₂ 1: 2 to 1: 5.

The second coating composition for a calcium-based inorganic substrate of the present invention contains a water-soluble alkali silicate compound and a pigment, and the pigment is a surface-treated inorganic pigment.

The third coating composition for a calcium-based inorganic substrate of the present invention has a solution A containing a surface-treated inorganic pigment and a curing agent, and a solution B containing a water-soluble alkali silicate compound.

In a preferred embodiment, the curing agent is a group consisting of a compound containing an alkaline earth metal or transition metal ion, a phosphate of an alkali metal, and an acid capable of neutralizing the water-soluble alkali silicate compound. At least one selected from the following.

[0012] The process for producing a coating composition for a calcium-based inorganic base material of the present invention comprises surface-treating an inorganic pigment dispersed in water with a silica-based compound and then mixing this with a water-soluble alkali silicate compound. Include.

The method for producing a colored calcium-based inorganic substrate according to the present invention includes a step of applying the first or second calcium-based inorganic substrate coating composition to a calcium-based inorganic substrate.

In another method for producing a colored calcium-based inorganic substrate according to the present invention, the solution A and the solution B of the third coating composition for a calcium-based inorganic substrate are mixed, and the resulting mixed solution is mixed with calcium. To the base inorganic substrate.

In the method for producing a colored calcium-based inorganic substrate according to the present invention, the coating composition for a first or second calcium-based inorganic substrate is applied to the surface of the calcium-based inorganic substrate and then contains a curing agent. Applying a liquid to the coating surface.

In a preferred embodiment, the curing agent is a group consisting of a compound containing an alkaline earth metal or transition metal ion, a phosphate of an alkali metal, and an acid capable of neutralizing the water-soluble alkali silicate compound. At least one selected from the following.

[0017] The colored calcium-based inorganic substrate of the present invention comprises:
It is obtained by applying the coating composition according to any of the above to a calcium-based inorganic substrate.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The water-soluble silica used in the present invention
As the alkali compound, water-soluble alkali silicate compounds
Any of them can be used. Such compounds
Is generally M ₂O (M is an alkali metal) and S
iO₂To its components. M₂O and SiO₂The ratio of
Preferably it is 1: 2 to 1: 5. Water-soluble alkali silicate
Examples of the compound include sodium silicate (orthosilicate).
Thorium, sodium sesquisilicate, sodium metasilicate
Etc.), lithium silicate, potassium silicate and the like. this
These compounds react with or react with polyvalent metal ions.
The alkali component (M) of the product to the silica network of the compound.
Removes insoluble silicic acid compounds
To achieve. A concentrated aqueous solution of a water-soluble alkali silicate compound is generally used
Is called water glass and is commercially available. Water-soluble silicate
Even if used alone, two or more potassium compounds are mixed.
May be used. For example, sodium silicate,
Titanium and potassium silicate combinations are preferably used
Can be

The water-soluble alkali silicate compound includes:
It is preferably a mixture of two or more water-soluble alkali silicate compounds containing lithium silicate at a predetermined ratio.
Lithium silicate is such that the Li ₂ O component of the compound is 2 to 20% by weight, preferably 4 to 20% by weight of the whole water-soluble alkali silicate compound.
Preferably, it is contained in an amount occupying 10% by weight.

This water-soluble alkali silicate compound is preferably contained in a proportion of 10 to 50% by weight in the whole composition containing a medium such as water. The water-soluble alkali silicate compound is more preferably contained in a proportion of 20 to 40% by weight, most preferably 30 to 40% by weight.

As the coloring agent contained in the composition of the present invention, a pigment is used. Pigments are colorants that are insoluble in water and organic solvents. As the pigment, any of an inorganic pigment and an organic pigment can be used.

As inorganic pigments, zinc yellow, lead red, graphite,
Cadmium red, cadmium yellow, cobalt blue, pyridian, lead white, ultramarine, titanium oxide, iron black, red iron oxide, alumina white, titanium black, lithopone, carbon black, and the like. Alizarin Lake, Indansun Blue, Eosin Lake, Quinacridone Red,
Quinacridone violet, copper phthalocyanine pigment,
Naphthol green, diamond black and the like.

The pigment used in the present invention includes:
Surface-treated inorganic pigments are preferred. This can be obtained by subjecting an inorganic pigment to a surface treatment using a silica-based compound. As the silica-based compound, the above-mentioned water-soluble alkali silicate compounds, colloidal silica and the like are used. The colloidal silica preferably has a particle size smaller than that of the pigment particles. Specifically, the thickness is 100 nm or less, preferably 4 to 100 nm, more preferably 6 to 40 nm.

For example, 0.1 to 10% by weight of an aqueous suspension containing 0.5 to 20% by weight, for example, 2% by weight of inorganic pigment particles.
By adding and contacting an aqueous solution or suspension containing 2% by weight, for example, 2% by weight of sodium silicate or colloidal silica, an insoluble silicate compound coating film is formed on the surface of the inorganic pigment particles. Preferably, an aqueous solution or suspension of a silica-based compound is added to an aqueous suspension of inorganic pigment particles to form an aqueous dispersion.
Stir for about 10 days, preferably about 4 days. At this time, the pH of the aqueous suspension of the inorganic pigment particles is set to a pH at which the surface charge (data potential) of the pigment does not become an isoelectric point and a pH at which the pigment does not dissolve. Is preferred. By setting the pH according to the type of the inorganic pigment, the surface of the inorganic pigment particles is effectively coated.

When the surface-treated inorganic pigment is added to an aqueous solution of a water-soluble alkali silicate compound to obtain a coating composition by using the surface-treated inorganic pigment, the surface of the inorganic pigment and the alkali silicate compound The reaction with is controlled. Furthermore, the chargeability of the inorganic pigment surface is improved. In addition, the formation of an aggregate of the pigment or an aggregate of the pigment and the water-soluble alkali silicate compound due to the rapid reaction between the water-soluble alkali silicate compound and the pigment is suppressed. Thus, when the pigment is a surface-treated inorganic pigment, it is excellent in dispersibility when added to an aqueous solution of an alkali silicate compound (having a relatively high pH). By using such a surface-treated inorganic pigment, the storage stability of the coating liquid is excellent. Even if the inorganic pigment settles during storage,
It is possible to easily redisperse by stirring.

The content of the pigment as the colorant varies depending on the type of the colorant and the purpose of use, but is usually 0.1 to 100 parts by weight of the water-soluble alkali silicate compound.
To 20 parts by weight, preferably 0.5 to 5 parts by weight.

Further, the composition of the present invention contains a dispersant, a reaction retarder, a surfactant and the like, if necessary.
The dispersant used is not particularly limited as long as it is a compound generally used as a dispersant. Water-soluble polymers such as water-soluble polycarboxylic acids, polyacrylic acids, and salts thereof are used. The dispersant is 1% by weight or less, preferably 0.01 to 1% by weight of the total solid content of the obtained coating liquid.
%, More preferably 0.05 to 0.5% by weight.

Examples of the reaction retarder include boric acid compounds and fluorine compounds. Examples of the boric acid compound include boric acid and sodium borate. As described later, the reaction retarder prevents gelation at an early stage when a composition containing a water-soluble alkali silicate compound and a curing agent at the same time is applied. The type of surfactant is not particularly limited as long as it is a commonly used compound. For example, polyoxyethylene alkyl phenyl ethers,
Examples thereof include polyoxyethylene alkyl allyl ethers and polyoxyethylene fatty acid esters. The surfactant is contained for the purpose of improving wettability with the base material, suppressing generation of bubbles, and the like.

The calcium-based inorganic substrate to which the composition of the present invention is to be applied includes, for example, any of calcium-based inorganic materials such as concrete, cement, gypsum, and stone (stone containing a calcium component). Is also used.

The curing agent contained in the composition of the present invention can be replaced with an alkali metal (M) of a water-soluble alkali silicate compound (M ₂ O.nSiO ₂ ; n is usually 2 to 5). Or a compound capable of removing the alkali metal and converting the water-soluble alkali silicate compound into an insoluble silicate compound. As the curing agent, at least one selected from the group consisting of a compound containing an alkaline earth metal or transition metal ion, a phosphate of an alkali metal, and an acid capable of neutralizing the water-soluble alkali silicate compound.
Seeds are used. Compounds containing divalent metal ions are preferred. Examples of such a metal include calcium, magnesium, barium, iron, manganese, copper, and zinc. Compounds containing the metal include calcium hydroxide,
Examples thereof include calcium chloride and an ammonia complex of cupric acetate. As the alkali metal phosphate, for example,
Potassium phosphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate and the like are used. Examples of the acid capable of neutralizing the water-soluble alkali silicate compound include acetic acid, hydrochloric acid, and phosphoric acid.

In order to form a coating film on the above-mentioned calcium-based inorganic substrate according to the present invention, for example, the above-mentioned water-soluble alkali silicate compound, a pigment, and if necessary, the above-mentioned dispersing agent and the like are contained in an aqueous medium. What is necessary is just to apply a coating liquid (1st liquid) on the said base material. The alkali silicate compound in the formed coating film reacts with a calcium compound (mainly calcium hydroxide) in the substrate with which the compound comes into contact to form insoluble calcium silicate. This forms a cured film on the surface.

By applying a second liquid containing a curing agent to the coating surface in addition to the first liquid, a coating film having higher hardness is formed. By applying the curing agent, the remaining water-soluble alkali silicate compound is changed into an insoluble silicate compound, and the coating film is further cured. The first
When the liquid can be applied in a relatively short time, a coating liquid containing both components of the first liquid and the second liquid is prepared, and this is applied to the surface of the base material. Is simple. For example, a liquid A containing a pigment (preferably a surface-treated inorganic pigment) and a curing agent, and a liquid B containing a water-soluble alkali silicate compound are prepared in advance, and these liquids A are applied during coating. It is convenient to mix the B solution and the B solution. When a long time is required before coating or after coating (usually 3 hours or more) after mixing, the above-mentioned method of applying the second liquid after the application of the first liquid because the mixed liquid gradually gels. Is recommended.

The first liquid and the second liquid or the mixed liquid are as follows:
It is applied to the substrate surface by a method generally used in the art. For example, a method such as coating with a brush or a roll coater, or coating by spraying is adopted. The thickness of the coating film formed on the substrate varies depending on the purpose, but is usually 0.1 to 100 μm, preferably 0.1 to 100 μm.
It is 50 μm, more preferably 1 to 20 μm.

As described above, a composition capable of easily forming a colored cured film with a pigment on the surface of a substrate made of a calcium-based inorganic material such as concrete is obtained.

This composition does not contain a large amount of organic components other than pigments, such as organic polymers. When an organic pigment is used as a pigment, the amount is small. Therefore, even if the composition is stored for a long period of time, denaturation hardly occurs. When a surface-treated pigment is used, the pigment contained in the composition is particularly excellent in dispersibility, and the composition is excellent in stability over time when stored.

The above composition preferably contains a water-soluble alkali silicate compound in a proportion of 10 to 50% by weight in the whole composition containing a medium such as water. When a coating solution composed of a composition containing a relatively high concentration of a water-soluble alkali silicate compound is applied onto a substrate, only the liquid component quickly penetrates into the porous portion of the substrate as in the related art. There is no such thing. A coating having an appropriate thickness is formed on the substrate, and the pigment is uniformly dispersed in the coating. Therefore, uniform coloring is possible as a whole. Since a part of the coating liquid permeates into the substrate, an anchor effect is obtained, and a cured film in which the coating film and the substrate are integrated is formed. The disadvantage that only the liquid component permeates the porous portion of the base material quickly and cannot be fixed on the pigment base material as in the related art is avoided.

Thus, when the composition of the present invention is used,
A colored cured film is easily formed on the surface of a substrate made of a calcium-based inorganic material. This cured film has a vitreous matrix consisting essentially of an insoluble silicate compound obtained from a water-soluble alkali silicate compound. The pigment contained is fixed on the surface of the substrate, and the surface of the coating film becomes a smooth vitreous film mainly obtained by curing the water-soluble alkali silicate compound. Therefore, surface hardness is high and excellent in water resistance and weather resistance,
Furthermore, it has excellent antifouling performance. Since the composition of the present invention is used as an aqueous coating liquid, it has no odor, has a favorable working environment, and is low in cost.

The colored substrate obtained by applying the composition of the present invention to a calcium-based inorganic substrate has a cured coating film having the above-mentioned excellent properties, and is therefore used in many fields including building materials. You.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

Example 1 Water suspension containing 2% by weight of a green inorganic pigment (ceramic color MD110; manufactured by Kawamura Chemical Co., Ltd .; spinel-type metal oxide containing cobalt, nickel, zinc, and titanium) 1 g of an aqueous solution of sodium silicate (50% aqueous solution of sodium silicate No. 3; sodium silicate No. 3 manufactured by Nippon Chemical Industry Co., Ltd.) was added dropwise to 238 g of the suspension (adjusted to pH 6), and the mixture was stirred at room temperature for 4 days. 239 g of a treated pigment suspension were obtained. Next, 1241 g of a 50% aqueous solution of sodium silicate No. 3 and an aqueous solution of lithium silicate (lithium silicate 35; manufactured by Nippon Chemical Industry Co., Ltd.) 2069
g, an aqueous solution of potassium silicate (potassium silicate 2K; manufactured by Nippon Chemical Industry Co., Ltd.) and 324 g of water were mixed to obtain 4045 g of a matrix water glass solution. 239 g of the above surface-treated pigment suspension and 382 g of a matrix water glass solution were uniformly mixed to obtain a composition (first liquid) of the present invention. In this first liquid, the concentration of the water-soluble alkali silicate compound is 16.6% by weight.

The first liquid was placed in a container and stored at room temperature for 60 days. The pigment was precipitated at the bottom of the container, but was easily mixed by gentle stirring to obtain a uniform coating liquid. This first liquid was applied to the surface of a square plate-shaped concrete substrate having a side of 10 cm, and then the second liquid was sprayed on the surface. This was left for one day to obtain a substrate having a green colored cured film formed on the substrate surface.

The color substrate thus obtained was subjected to an acceleration test for 70 hours using a fade meter. For the strength of the coating film, measure the hardness with a Mohs hardness tester and
A cross-cut tape adhesion test according to ISK-5400 was performed. In the accelerated test, no fading of the coating film on the substrate was observed. The Mohs hardness was 6.5, and the result of the grid test was 25/25, which was a good result.

(Example 2) 3 g of cupric oxide monohydrate was dissolved in 10 g of water, and concentrated ammonia water (28%) 1
5 g was added to obtain a blue transparent copper complex solution. This was added to and mixed with 239 g of the surface-treated pigment suspension obtained in Example 1 to obtain a liquid (liquid A) containing a pigment and a curing agent. The solution A was mixed with 382 g of the matrix water glass solution (hereinafter referred to as solution B) obtained in Example 1 to obtain a coating composition. In this coating composition, the concentration of the water-soluble alkali silicate compound is 16.2% by weight.

This composition was applied to the surface of a square plate-shaped concrete base material having a side of 10 cm, and allowed to stand for one day to obtain a base material having a green colored cured film formed on the base material surface.

The same test as in Example 1 was conducted on the obtained colored base material. In the accelerated test, no fading of the coating film on the substrate was observed. The Mohs hardness was 6.5, and the result of the grid test was 25/25, which was a good result.

(Embodiment 3) The above ceramic color MD1
In place of 10, a blue inorganic pigment (ceramic color AO2
00; manufactured by Kawamura Chemical Co., Ltd .; a spinel-type metal oxide containing cobalt and aluminum) was used. However, the pH at the time of performing the surface treatment of the inorganic pigment was adjusted to 2.

The same test as in Example 1 was performed on the obtained colored base material. In the accelerated test, no fading of the coating film on the substrate was observed. The Mohs hardness was 6.5, and the result of the grid test was 25/25, which was a good result.

(Embodiment 4) The above ceramic color MD1
Red inorganic pigment (Biferox 110
C: manufactured by Bayer K.K .; a metal oxide containing iron oxide (III)). However, the pH at the time of performing the surface treatment of the inorganic pigment was adjusted to 4.

The same test as in Example 1 was performed on the obtained colored base material. In the accelerated test, no fading of the coating film on the substrate was observed. The Mohs hardness was 6.5, and the result of the grid test was 25/25, which was a good result.

Comparative Example 1 A 50% aqueous solution of sodium silicate No. 3, lithium silicate 35 and potassium silicate 2K were respectively 720 g, 1160 g and 210 g, and the amount of water was 1955 g. 4045 g of a matrix water glass solution was obtained. Using this, a first liquid was obtained in the same manner as in Example 1. However, the surface treatment of the pigment was not performed, and 1% was added to 238 g of an aqueous suspension containing 2% by weight of the pigment.
g of water was added to form a pigment suspension. The concentration of the water-soluble alkali silicate compound in the first liquid was 9.4% by weight.

The first liquid was stored in a container at room temperature for 60 days. The pigment settled at the bottom of the container and was not easily mixed with only slight agitation. After sufficiently stirring and mixing the first liquid, the first liquid was applied to the surface of a square plate-shaped concrete base material having a side of 10 cm, but a uniformly colored coating film was not obtained.

[0052]

According to the present invention, a composition capable of easily forming a colored cured film containing an inorganic pigment on the surface of a calcium-based inorganic material such as concrete can be obtained. This composition is excellent in dispersibility and stability over time of the inorganic pigment, and can form a uniform colored coating film. Since it is based on an aqueous solvent, it does not pollute the working environment and is low cost. The coating film obtained from this composition is glassy with a desired color, having a smooth surface and high strength, and is excellent in adhesion to a substrate. The obtained coating film is excellent in antifouling property and weather resistance. Therefore, a colored substrate obtained by applying the composition to a calcium-based inorganic substrate is used in many fields including building materials.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisashi Ogawa 1-2-113 Shinmachi, Nishi-ku, Osaka-shi, Osaka Shinmachi Building 4th Floor Inside Ashford Co., Ltd. (72) Inventor Masanori Hori Nakadoku, Shimogyo-ku, Kyoto, Kyoto Minamicho 17 Kyoto Research Park Kansai New Technology Research Institute Co., Ltd. (72) Inventor Tosumi Fukui 17 Nakado Tokinancho, Shimogyo-ku, Kyoto City, Kyoto Prefecture Kyoto Research Park Kansai New Technology Research Institute Co., Ltd. F term (reference) 4G028 DA01 DB05 DB06 4J038 AA011 HA116 HA186 HA416 HA446 HA451 HA456 JC38 KA03 KA08 KA15 KA20 MA10 NA03 NA11 NA25 NA26 PC01

Claims (11)

[Claims] 1. A coating composition for a calcium-based inorganic base material containing a water-soluble alkali silicate compound and a pigment, wherein the water-soluble alkali silicate compound is contained in a proportion of 10 to 50% by weight. 2. The method according to claim 1, wherein the water-soluble alkali silicate compound is M ₂ O.
(M is an alkali metal) and SiO ₂ as its component, the ratio of the _{M 2} O and SiO ₂ is 1: 2 to 1: 5 A composition according to claim 1. 3. A coating composition for a calcium-based inorganic base material containing a water-soluble alkali silicate compound and a pigment, wherein the pigment is a surface-treated inorganic pigment. 4. A coating composition for a calcium-based inorganic substrate, comprising a liquid A containing a surface-treated inorganic pigment and a curing agent and a liquid B containing a water-soluble alkali silicate compound. 5. The compound in which the curing agent contains an alkaline earth metal or transition metal ion, a phosphate of an alkali metal,
The composition according to claim 4, wherein the composition is at least one selected from the group consisting of an acid capable of neutralizing the water-soluble alkali silicate compound. 6. The method for producing a composition according to claim 3, wherein the inorganic pigment dispersed in water is subjected to a surface treatment with a silica-based compound, and then treated with a water-soluble alkali silicate compound. Mixing. 7. A method for producing a colored calcium-based inorganic substrate, comprising a step of applying the coating composition for a calcium-based inorganic substrate according to claim 1 to a calcium-based inorganic substrate. 8. A method for producing a colored calcium-based inorganic substrate, comprising mixing the solution A and the solution B according to claim 4, and applying the resulting mixture to a calcium-based inorganic substrate. 9. After applying the coating composition for a calcium-based inorganic substrate according to any one of claims 1 to 3 to a surface of the calcium-based inorganic base material, a liquid containing a curing agent is applied to the coated surface. A method for producing a colored calcium-based inorganic substrate, comprising a step of applying. 10. The curing agent is at least selected from the group consisting of a compound containing an alkaline earth metal or transition metal ion, a phosphate of an alkali metal, and an acid capable of neutralizing the water-soluble alkali silicate compound. The method for producing a colored calcium-based inorganic substrate according to claim 9, which is one kind. 11. A colored calcium-based inorganic substrate obtained by applying the coating composition according to claim 1 to a calcium-based inorganic substrate.