JP2001049147A - Coating composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a coating composition easily applicable in a relatively short time, capable of markedly reducing problems such as air pollution, and capable of giving coating films of high hardness, water resistance, resistance to moisture/water permeability, corrosion-proofness, heat resistance, etc., by including, as the main components, colloidal silica and a calcium silicate. SOLUTION: This coating composition is obtained by including, as the main components, (A) colloidal silica and (B) a calcium silicate (pref. Wollastonite) and, pref. (C) a metal oxide-based hardening agent, esp. titanium oxide surface- coated with a metal oxide-based hardening agent; wherein it is preferable that, for the component B, in particular, such an aqueous dispersion containing 0.3-0.6 wt.% of an alkaline matter as to be prepared by dispersing the component B about 1-100 nm in particle size in water so as to contain 15-50 wt.% thereof in the aqueous dispersion, the compounding amount of the component B is 10-120 pts.wt. based on 100 pts.wt. of the component A (on a solid basis), and the compounding amount of the component C is 15-120 pts.wt. based on a total of 100 pts.wt. of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a coating composition. More specifically, it is a water-based inorganic coating composition containing no organic component or having a very low content even if it contains, and has excellent water resistance, weather resistance, rust resistance, durability, coloring property, workability, and the like. Paint compositions.

[0002]

2. Description of the Related Art In recent years, due to air pollution not only in the working environment but also on a global environmental scale, a large amount of organic solvents discharged from coating materials has been regarded as a problem. Therefore, as measures to reduce the amount of organic solvents in organic paints, water-based, high-solid, powdered, conversion to solventless is being promoted, among these water-based paints, since the main solvent is water, Organic solvent, so-called VO
It is the most practical because it can reduce the content of C, greatly reduce the air pollution, fire danger and toxicity problems of organic solvent-based paints, and it is relatively easy to convert from conventional solvent-based paints. I'm advancing.

[0003] However, polymers used in water-borne paints which are usually dried at room temperature must use polymers having a relatively large number of hydrophilic groups, and various surfactants and hydrophilic agents must be used to stably disperse the polymer in water. A dispersion stabilizer must be used, and since these hydrophilic components easily remain in the coating film, the coating has poor water resistance.

[0004] Inorganic coatings composed of colloidal metal oxides such as colloidal silica and colloidal alumina or water-soluble alkali metal silicates such as sodium silicate, potassium silicate and lithium silicate are aqueous coatings mainly using water as a dispersion medium. It has the advantages of water-based paints, and the cured film has heat resistance, fire resistance, smokelessness, no toxic gas generated during combustion, high hardness, good abrasion resistance, good air permeability, etc. Has an advantage as an inorganic paint. However, most of them have an alkali component in the coating film, and therefore have extremely poor moisture resistance or water resistance, and are practically very limited in application. In addition, a coating of a colloidal metal oxide generally has poor film-forming properties and poor adhesion, so that a large amount of an organic film-forming aid is required, which significantly impairs the characteristics of the above-mentioned inorganic coatings. On the other hand, in the case of a coating made of a water-soluble alkali metal silicate in order to improve the water resistance and durability of the coating film, a work such as a heat treatment at about 120 to 280 ° C. or a dealkalization treatment is required after application. Is complicated and requires a long time.

[0005] By the way, as a paint comprising colloidal silica and inorganic fiber powder, there has been conventionally known, for example, Japanese Patent Publication No. 56-23466 discloses colloidal silica, pigment, inorganic filler, inorganic fiber powder. An anti-condensation paint consisting of: Examples of the inorganic fiber powder include asbestos and rock wool, and it is disclosed that the solid content of colloidal silica is about 3 to 30% by weight of the total solid content.

[0006] However, this publication does not disclose any inorganic coating obtained by combining calcium silicate and colloidal silica, and the inorganic fiber powder such as rock wool used in the coating composition has a small amount. In order to greatly increase the viscosity of the composition, the composition cannot generally exceed 10% by weight with respect to the total solids of the entire coating composition, and although the effect of preventing dripping can be obtained, a large amount of inorganic fibers is required. The effect of obtaining a strong coating film obtained by blending cannot be ensured.

Japanese Patent Publication No. 11980/1986 describes an inorganic coating composition containing a specific filler, a water-soluble silicate or colloidal silica. As the silicate, potassium silicate, lithium silicate and sodium silicate are used. Such an alkali metal silicate is used, an alkaline earth metal silicate such as calcium silicate is not used, and no colloidal silica is used with this. In addition, JP-A-50-127930, JP-A-50-127933,
JP-A-50-157423, JP-B-59-34671.
Discloses inorganic coating compositions using silicates and modified silicates, but these silicates do not contain alkaline earth metal silicates such as calcium silicate, and both of them contain phosphoric acid. It is essential to use a salt or a boric acid compound in combination. Japanese Patent Publication No. 6-11667 describes a surface treatment agent containing ammonium silicate, colloidal silica, and aluminum metaphosphate A type. There is no description of a coating composition using colloidal silica.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a water-based or inorganic paint which does not impair the advantages of air pollution, fire danger, and toxicity. Another object of the present invention is to provide a water-based complete inorganic coating composition which is excellent in moisture permeability and water permeability, weather resistance, rust resistance, heat resistance and durability, and can be easily applied in a relatively short time.

[0009]

The present invention relates to a coating composition containing colloidal silica and calcium silicate as main components.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Each component of the coating composition of the present invention will be described below. The colloidal silica used in the present invention is a silicate colloid obtained by removing as much alkali as possible from an alkali silicate solution, and has a particle diameter of usually 1 to 100 nm, preferably 5 to 30 nm. it can. Among them, alkali (Na ₂ O) dispersed in water so that the silicate colloid becomes 15 to 50% by weight.
Those containing 0.3 to 0.6% by weight per minute are preferred. When the alkali content is large, the film-forming property is good, but the water resistance is poor, which is not preferable. As the colloidal silica used in the present invention, commercially available colloidal silica can be used, and trade names "Snowtex S", "Snowtex 40" (manufactured by Nissan Chemical Industries), "Adelite AT30" (manufactured by Asahi Denka Kogyo). And the like.

Examples of the calcium silicate used in the present invention include wollastonite, zonotolite and the like. Wollastonite is a naturally occurring white needle-shaped crystal mainly composed of CaSiO ₃ , and is widely used as a cement raw material and a plastic reinforcing agent because of its low cost. The wollastonite used in the present invention may be fibrous or lump, as it is, pulverized, classified, or calcined, and may be synthesized. Among them, those classified so as to be as homogeneous as possible or those synthesized are preferred.
The fibrous material is preferably β-type wollastonite having a large aspect ratio depending on the pulverization method and the production place, from the viewpoint of improving the dart impact resistance and the adhesion. Specifically, a component having an aspect ratio of 6 or more contains 60% by weight or more, preferably 80% by weight or more, and a component having a fiber length of 40 µm or less and a fiber diameter of 5 µm or less is 80% by weight or more, preferably 95
It is preferable to use wollastonite containing not less than% by weight. Commercially available products include “Vistal” (manufactured by Otsuka Chemical).

Zonotorite contains CaSiO ₃ as a main component and is equivalent to wollastonite. A component having a fiber length of 40 μm or less and an aspect ratio of 6 or more contains 60% by weight or more.
Preferably, it is contained in an amount of 80% by weight or more. Commercially available products include zonotolite whiskers (manufactured by Otsuka Chemical).

The amount of the calcium silicate is 10 to 10 parts by weight of colloidal silica (solid basis).
Preferably it is 120% by weight, more preferably 13% by weight.
It is good to be ~ 85% by weight. If the amount of calcium silicate is too small, not only does the film-forming property deteriorate, cracks occur, but also the adhesion is poor. On the other hand, if the amount is too large, it is good in preventing cracks, but the cohesiveness of the pigment is reduced, the adhesion is impaired, and disadvantages occur.

A metal oxide-based curing agent can be used in the coating composition of the present invention, if necessary. Metal oxide-based curing agent is a metal oxide coated on an inorganic carrier,
For example, it is obtained by operations such as spraying, sedimentation and / or pulverization. As metal oxides, Mg, Ca, Ba, Ti, Z
oxides of metal elements such as r, Fe, Zn, Al, Si, Sn, etc., and aluminum oxide (A
l ₂ O ₃ ) and titanium oxide (TiO ₂ ).
The metal oxide to be coated may be used alone or in combination of two or more.

[0015] A preferred metal oxide-based curing agent uses titanium oxide as an inorganic carrier. The titanium oxide produced by a known sulfuric acid method or chlorine method is coated with aluminum hydroxide and / or silicon dioxide. And coated with aluminum hydroxide and zinc hydroxide, and the like, which is preferable in that the coating film has excellent surface smoothness. These metal oxide-based curing agents are commercially available and are referred to as “Titanium White JR
800 "," Titanium White JR801 "," Titanium White JR7 "
01 "," Titanium White JR901 "(manufactured by Teica) and the like.

The compounding amount of the metal oxide-based curing agent is preferably 15 to 120% by weight, more preferably 25 to 120% by weight, based on 100 parts by weight (solid content) of the total of calcium silicate and colloidal silica. The content is preferably set to と す る 100% by weight. If the amount of the metal oxide-based curing agent is too small, not only the strength of the coating film is reduced but also the concealing property is reduced. On the other hand, if the amount is too large, it is preferable in terms of concealing properties, but the strength of the coating film is reduced and disadvantages occur.

The coating composition of the present invention comprising colloidal silica and calcium silicate is uniformly mixed and dispersed using water as a dispersion medium.

Since the coating composition of the present invention is water-based, in addition to the bonding of free silicate ions of colloidal silica with calcium ions eluted in calcium silicate, the metal oxide-based curing agent optionally used in combination is used. Since the agent chemically reacts with the excess silicate ions in the conjugate, after the coating, these reactions are further promoted by the volatilization of water, and are excellent in dryness even at room temperature and form a water-insoluble film. Therefore, the forced drying treatment is not always required, and the recoating can be easily performed. Further, since no alkali removal treatment is required and the recoating time is short, workability is remarkably improved.
Further, the coating film has a characteristic that it has a semi-gloss and does not crack. Although the coating film of the coating composition of the present invention has sufficient water resistance, it is a moisture-permeable and water-permeable coating film. A water-proof (repellent) water repellent can be added to such an extent that the water-repellent does not impair.

The coating composition of the present invention may contain, if necessary,
It is also possible to make colored paints using red iron oxide, graphite, and other calcined composite metal oxide pigments (brown, green, yellow, blue, black, etc.). If necessary, carbonated lime powder, clay, talc, alumina Extender pigments such as white, mica powder, silica powder, rust preventive pigments such as aluminum phosphate, zinc molybdate, and zinc powder; metal powders such as aluminum powder and stainless flake; pigments such as pearl mica powder and flaky iron oxide powder May be added, and in addition to these, additives such as a dispersion wetting aid, a curing accelerator, and an antifoaming agent may be appropriately compounded as long as the object of the present invention is not impaired.
When used in a light color, a commercially available liquid colorant for a general emulsion paint (universal color) having a large coloring power may be added for toning as long as the properties of the present coating composition are not impaired. Good.

The production of the coating composition of the present invention can be carried out by a usual aqueous coating production method, and does not particularly require a unique apparatus. During storage and distribution, the coating composition of the present invention can be handled as a one-pack type, but is usually used in two or more parts and mixed immediately before use. When the coating composition of the present invention is used in a two-pack type, the first liquid mainly contains a colloidal silica component, and the second liquid mainly contains a calcium silicate component, a metal oxide-based curing agent and other components. It is preferably a liquid.

The coating method of the coating composition of the present invention includes:
The undiluted solution or, if necessary, dilution with water can be used for brushing, roll brushing, air spraying, airless spraying, dip coating, or the like, and can also be applied as needed.

The coating composition containing the colloidal silica, calcium silicate and metal oxide-based curing agent of the present invention as main components does not impair the original advantages of water-based inorganic coatings, 1) coating workability, and 2) drying. , 3) water resistance, 4) weather resistance, 5) rust resistance, and 6) finish with excellent durability. In addition to having an abundant color tone (possible from dark to light colors), it is possible to achieve a "half gloss" finish not found in general dry-drying water-based inorganic paints.

The substrate (object to be coated) on which the coating composition of the present invention is applied includes, for example, concrete, mortar,
It is a cement material such as a slate or a tile, a fired brick, or the like, and is suitable for a durable finish thereof, and a coating for a heat-resistant and rust-proof finish of an iron or steel product.

The coating composition of the present invention is an inorganic coating composition containing no or almost no organic substances.
Not only the coating film but also the undiluted solution is odorless, has a very low effect on the human body, is used for interiors of schools and hospitals, and has no danger of flammability during construction. It is also suitable for repainting inside roads and tunnels, and for durability finishing of mortar spraying slopes. In addition, since an appropriate moisture-permeable film is formed, it can also be recommended for interiors requiring moisture permeability.

[0025]

The present invention will be described below with reference to examples and comparative examples, but is not limited thereto. It is to be noted that “parts” means “parts by weight”.

Example 1 87.2 parts (in terms of solid content) of Snowtex S were weighed into a container, 11.9 parts of vistal was added thereto, and the mixture was dispersed for about 30 minutes with a small disper, and then the viscosity was adjusted. DK thickener SCT-2 prepared in 2% aqueous solution for the purpose of
70 (0.9 parts in terms of solid content), and about 10
Dispersion was continued for a minute to prepare a coating composition.

Example 2 A coating composition of Example 2 was obtained in the same manner as in Example 1. Example 3 DK thickener SCT-270 prepared in 2% aqueous solution
(0.7 parts in terms of solid content) was weighed into a container, 16.1 parts of Vistal and 34.7 parts of Titanium White JR800 were added, kneaded with a table mixer for about 20 minutes, and then with a small water-cooled three-roll mill. Dispersion was performed twice to prepare a paste of vistal and titanium white. In the preparation, deionized water was used for viscosity adjustment and work. Before coating, 48.5 parts (in terms of solid content) of Snowtex S are added to the dispersed paste to make it uniform. Note that the above-mentioned separate type paint is treated with vistal and titanium white dispersion paste as main components, and Snowtex S as a binder.

Examples 4 to 8 According to Example 3, two-pack type coating compositions of Examples 4 to 8 were prepared. Example 9 According to Example 3, 2% DK thickener SCT-270
Vistal, titanium white JA-1 and No. 3 zinc white described in the table were added and dispersed therein to prepare a main ingredient of Example 9.
At the time of use, a predetermined amount of a binder described in the table was added to make the mixture uniform. Examples 10 to 12 Examples 10 (black) and 11 (red rust) according to Example 3.
And 12 (yellow) base materials were prepared. Example 10
An antifoaming agent (BYK-W) was added to the base materials No. to No. 12.

Example 13 About 1/3 of 2% DK Thickener SCT-270 (0.8 parts in terms of solid content) and 16.3 parts of Vistal were kneaded with a desktop mixer for about 20 minutes, and then mixed with The mixture was dispersed twice by a water-cooled three-roll mill to prepare a vistal dispersion paste (referred to as paste 1). Next, aluminum paste 48-316 (23.8 parts in terms of solid content) was weighed into a container, and 10 parts of ethyl cellosolve and the remaining amount of thickener SC were measured.
T-270 was added, and the mixture was stirred with a desktop mixer for about 20 minutes to make it uniform, thereby producing an aluminum paste (referred to as paste 2). In use, Paste 1 and Paste 2 were added and mixed, and a predetermined amount of a binder was added to the mixture to make it uniform.

Example 14 2% DK Thickener SCT-270 (0.4 parts in terms of solid content) was weighed into a container, and 18.6 parts of Vistal was added. 1). Next, 7.4 parts of ethyl cellosolve is added to stainless flake RFA4000 (41.9 parts in terms of solid content) to make it uniform (referred to as paste 2). At the time of use, a predetermined binder was added to a mixture obtained by adding the paste 1 and the paste 2, and the mixture was stirred to be uniform.

Example 15 2% DK thickener SCT-270 according to Example 14
17.8 parts of Vistal and 3.8 parts of Ethyl Cellosolve were weighed into a container (0.4 parts in terms of solid content), and kneaded and dispersed, to produce a bistable dispersion paste (referred to as paste 1). did. At the time of coating, paste 1 was mixed with a predetermined amount of a binder and zinc dust F shown in the table to make the paste uniform.

[0032]

[Table 1]

[0033]

[Table 2]

1) Fibrous calcium silicate (Wollastonite) manufactured by Otsuka Chemical Co., Ltd. 2) Water-dispersible silica sol manufactured by Nissan Chemical Industry Co., Ltd. (heating residue: 30.9%) 3) Nissan Chemical Industry Co., Ltd. 4) Water-dispersible silica sol (heating residue: 40.8%) 4) Asahi Denka Kogyo Co., Ltd. water-dispersible silica sol (heating residue: 30.6%) 5) Daiichi Kogyo Seiyaku Co., Ltd. polyether polyurethane・ Butyl carbitol aqueous solution (heating residue 20%) 6) Alumina, silica-treated titanium oxide manufactured by Teica Co., Ltd. 7) Alumina-treated titanium oxide manufactured by Teica Co., Ltd. 8) Alumina, silica, zinc oxide processed by Teika Co., Ltd. Titanium oxide 9) Alumina, zirconia treated titanium oxide manufactured by Teica

10) Untreated titanium oxide manufactured by Teika Corporation 11) Composite metal oxide black pigment manufactured by Dainichi Seika Co., Ltd. 12) Nittan Morishita 13) Titanium Yellow manufactured by Bayer Corporation 14) Toyo Aluminum ( Leafing type stainless steel flake manufactured by Toyo Aluminum Co., Ltd. 15) Water-based leafing type aluminum flake manufactured by Toyo Aluminum Co., Ltd. 16) Shirasu Chemical Industry Co., Ltd. 17) Shiraishi Industry Co., Ltd. 18) Big Chemie Japan 19) Shirasu Chemical Industry Co., Ltd. The ratios in the table below indicate the solid content conversion amounts (the same applies hereinafter).

Comparative Examples 1 to 7 In a similar manner, the components shown in Table 3 were blended to prepare inorganic coating materials of Comparative Examples. Except for Comparative Example 7 below, the method of preparing each sample of Comparative Example was performed in accordance with the sample preparation procedure of Examples described in Tables 1 and 2.

Comparative Example 7 Lithium silicate LSS-75 (2 in terms of solid content)
6.5 parts) and 16.2 parts of Vistal were weighed into a container and dispersed with a small disper for about 30 minutes to prepare a base material.
Before painting, a predetermined amount of zinc dust F was added to make the powder uniform.

[0038]

[Table 3]

21) Fibrous potassium hexatitanate (neutral) manufactured by Otsuka Chemical Co., Ltd. 22) Fibrous magnesium borate manufactured by Otsuka Chemical Co., Ltd. 23) Fibrous aluminum borate manufactured by Shikoku Chemicals Corporation 24) Showa Mining Fibrous magnesium silicate manufactured by Co., Ltd. 25) Fibrous magnesium silicate manufactured by Showa Mining Co., Ltd. 26) Nissan Chemical Industries, Ltd. 21-3% lithium silicate (heating residue: 21.3%)

Test Example 1 Single-side polished glass plate (150 × 70 ×
2 mm) on the polished surface side, using a brush with a coating amount of 1.2 to 1.3 g / sheet for each sample, drying in a room for about 20 minutes, and then applying a second coating with a brush with the same coating amount The specimen was cured for 5 days in the room to prepare a specimen. In addition, the reason why the glass plate was used as the base material in this test was to consider the influence of calcium ions and the like. In addition, the test method followed the following. Table 4 shows the results
To # 6.

(1) Miscibility: Evaluated according to the difficulty in mixing the main agent and the binder at a predetermined ratio to make them uniform. ◎: good, ○: slightly time-consuming but sufficiently mixed, △:
It takes a considerable amount of time. ×: Agglomerates are formed and are not mixed. (2) Pot life: Usable time after preparing the coating composition was measured. ◎: 8 hours or more, Δ: 1 to 8 hours, ×: less than 1 hour (3) Coating workability: JIS K 5400 6.1 (brush coating) ：: good, Δ: brush weight (4) Drying time : JIS K 5400 6.5 ◎: Cured within 20 minutes (5) Overcoating compatibility: JIS K 5400 6.8: No hindrance, Δ: Slightly heavy brush, ×: Checking or cracking (6) ) Appearance of coating film JIS K 5400 7.1: Normal, ○: Crushing, slight surface roughness observed,: Crushing observed. Or, discoloration is recognized. ×: Checking or cracking is recognized. (7) Pencil scratching value: JIS K 5400
4.2 (8) Tape application test: A cellophane adhesive tape having a width of 12 mm was strongly pressed on the surface of the coating film, and then immediately separated,
Observe and evaluate the degree of contamination (adhesion) by the coating film on the tape surface. : No color transfer, ○: Very slight color transfer, Δ: Color transfer,
×: color transfer and peeling (9) Adhesion: JIS K 5400 8.5.3 (X
(Cut tape method) (10) Gloss degree at 60 degrees: JIS K 5400 7.
6 (Specular gloss measurement method) (11) Water resistance: JIS K 5400 8.19 After dipping in clear water for 10 days, pull up, observe the state of the coating film, and check for any abnormalities. : No abnormality, ○: Coating slightly eluted, Δ: Coating component considerably eluted, ×: Coating component almost eluted, base exposed

[0042]

[Table 4]

[0043]

[Table 5]

[0044]

[Table 6]

Test Example 2 Polished with sandpaper # 40 and washed with toluene 1
50 × 70 × 0.8 mm steel plate (JIS K5410
Table 8 shows the results of a test performed on a sample prepared using the coating system shown in Table 7 below (SPCC1505004).

[0046]

[Table 7]

Note) In the above coating system, the primer was 180 g /
In coat-weight of m 2 ^/ dose, each overcoat was coated with a brush in a coating with the amount of 130 g / m 2 ^/ dose, this was subjected after curing for 5 days room.

(1) Color of coating film: visual observation (2) Film thickness: measured by elcometer (3) Pencil scratching value: JIS K 5400
4.2 (4) Adhesion: JIS K 5400 8.5.3 (5) Water resistance: Dipped in clean water at 20 ° C. for 30 days ◎: No abnormality, ×: Almost all coating film components elute, exposing base 6) Salt water resistance: immersed in a 3% saline solution at 20 ° C. for 15 days ◎: no abnormality, Δ: discolored, ×: spot rust generated (7) Solvent resistance: immersed in each solvent at 20 ° C. for 10 days ◎ : No abnormalities (8) Heat resistance: After heating at 500 ° C for 3 hours, immediately cooling with water,
Leave at room temperature (1 hour). 5 repetitions. ：: no abnormality, Δ: discolored, ×: about 剥離 peeling (9) Fire resistance: placed in an electric furnace (700 ± 50 ° C.) for 30 minutes, taken out, left at room temperature, and observed the coating film. ◎: no abnormality, Δ: discoloration, ×: about 1/2 peeling

[0049]

[Table 8]

From the test results shown in Table 8, it is understood that the inorganic coating composition of the present invention is an excellent complete inorganic coating material that can be sufficiently used.

[0051]

The coating film obtained from the coating composition of the present invention is excellent in hardness, water resistance, weather resistance, rust resistance, heat resistance, durability and workability. , GRC (glass fiber reinforced)
It is useful as odorless, long-term cosmetic and rust preventive paint for concrete, slate, roof tile, fired brick, and steel. Further, since the coating composition forms a water-resistant moisture-permeable and water-permeable film, it is extremely effective not only for dew condensation prevention but also for parts where general organic coating films are liable to blister and easily cause problems. When the coating composition is overcoated, it is not necessary to particularly limit the overcoating time.

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 10, 1999 (1999.8.1
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Zonotorite contains CaSiO ₃ as a main component and is equivalent to wollastonite. A component having a fiber length of 40 μm or less and an aspect ratio of 6 or more contains 60% by weight or more.
Preferably desirably those containing more than 80 wt%. Commercially available products include zonotolite whiskers (manufactured by Otsuka Chemical).

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

The amount of the calcium silicate is 10 to 10 parts by weight of colloidal silica (solid basis).
Preferably it is 120 parts by weight, more preferably 13 parts by weight.
It is good to be ~ 85 parts by weight. If the amount of calcium silicate is too small, not only does the film-forming property deteriorate, cracks occur, but also the adhesion is poor. On the other hand, if the amount is too large, it is good in preventing cracks, but the cohesiveness of the pigment is reduced, the adhesion is impaired, and disadvantages occur.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

The amount of the metal oxide-based curing agent is preferably 15 to 120 parts by weight, more preferably 25 to 120 parts by weight, based on the total amount of 100 parts by weight (solid content) of calcium silicate and colloidal silica. It is preferable that the amount be 100 parts by weight. If the amount of the metal oxide-based curing agent is too small, not only the strength of the coating film is reduced but also the concealing property is reduced. On the other hand, if the amount is too large, it is preferable in terms of concealing properties, but the strength of the coating film is reduced and disadvantages occur. ────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] August 27, 1999 (1999.8.2
7)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Each component of the coating composition of the present invention will be described below. The colloidal silica used in the present invention is a silicate colloid obtained by removing as much alkali as possible from an alkali silicate solution, and has a particle diameter of usually 1 to 100 nm, preferably 5 to 30 nm. it can. Among them as silicic acid colloids is 15 to 50 wt%, dispersed in water, an alkali _(Na 2 O)
Those containing 0.3 to 0.6% by weight per minute are preferred. When the alkali content is large, the film-forming property is good, but the water resistance is poor, which is not preferable. As the colloidal silica used in the present invention, commercially available colloidal silica can be used, and trade names "Snowtex S", "Snowtex 40" (manufactured by Nissan Chemical Industries), "Adelite AT30" (manufactured by Asahi Denka Kogyo). And the like.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0038

[Correction method] Change

[Correction contents]

[0038]

[Table 3]

Continued on the front page (72) Inventor Toshiyuki Honda 10-5, Kawagishi-cho, Suita-shi, Osaka Inside Cerastar Paints Co., Ltd. F term (reference) 4J038 AA011 HA161 HA211 HA441 HA451 KA03 KA15 MA08 NA03 NA04 NA11 NA14 NA15 NA23 PB05 PC02 PC03 PC04

Claims (4)

[Claims] 1. A coating composition comprising colloidal silica and calcium silicate as main components. 2. The coating composition according to claim 1, wherein the calcium silicate is wollastonite. 3. The coating composition according to claim 1, wherein a metal oxide-based curing agent is added. 4. The coating composition according to claim 3, wherein the metal oxide-based curing agent is a surface-treated titanium oxide.