JP7209015B2 - Paint composition kit and its use - Google Patents

Description

The present invention relates to a coating composition kit and uses thereof.

Inorganic zinc-rich paint is a coating composition containing an inorganic resin such as a silicate hydrolysis condensate as a binder component and containing a large amount of zinc powder. For example, a one-component, one-powder coating composition kit is known. there is Inorganic zinc-rich paint can prevent corrosion of steel materials through the sacrificial anti-corrosion action of zinc and the formation of an oxide film with high barrier properties in a corrosive environment. in use.

An example of an inorganic zinc-rich paint is known to contain a hydrolytic condensate of silicate as a binder component and to be cured by moisture.
By the way, inorganic zinc-rich paint is sometimes applied to steel bolted joints in order to increase the sliding friction force of the joint surface. In such cases, the slip coefficient is generally 0.4 to 0.5, and Patent Document 1 discloses a zinc-rich coating composition having a slip coefficient exceeding 0.5.

JP-A-2003-306638

As a result of investigations by the present inventors, in order to increase the slip coefficient of the coating film of inorganic zinc-rich paint, an attempt was made to manufacture a paint composition kit having a mixed powder obtained by mixing zinc powder with extender pigments and special pigments. In this case, it is necessary to classify the mixed powder at the time of production, and depending on the pigment, poor mixing of the powders is likely to occur, making the classification difficult, time-consuming, and costly, which is not economical.

On the other hand, in a paint composition kit having a first agent containing a binder component and a second agent containing zinc powder, if the pigment is dispersed in the first agent, there is a problem that the storage stability is deteriorated. I understood it. For example, if the high-hardness pigment described in Patent Document 1 is added to the first agent in order to increase the slip coefficient of the coating film, the storage stability deteriorates. As an inorganic zinc-rich paint, it may be necessary to store for a long period of 12 months, and deterioration in the storage stability of the first agent poses a problem.

An object of the present invention is to provide a coating composition kit capable of forming a coating film having excellent long-term storage stability and, for example, a superior slip coefficient at bolted joints of steel materials.

The present inventors have diligently studied to solve the above problems. As a result, the inventors have found that the above problems can be solved by a coating composition kit having the following constitution, and have completed the present invention.
The present invention relates to, for example, the following [1] to [10].

[1] A coating composition comprising a first agent containing a siloxane-based binder (A), kaolin (B), and a pigment (C) having a Mohs hardness of 5 or more, and a second agent containing zinc powder (X) things kit.

[2] The coating composition kit according to [1] above, wherein the siloxane-based binder (A) has a weight average molecular weight (Mw) of 500 to 10,000.
[3] The paint according to [1] or [2] above, wherein the siloxane-based binder (A) is a condensate of at least one compound (A1) selected from tetraalkoxysilanes and alkyltrialkoxysilanes. composition kit.

[4] The paint composition kit according to any one of [1] to [3], wherein the pigment (C) contains at least one selected from yellow iron oxide, potassium feldspar and silica.
[5] A coating composition obtained by mixing at least the first agent and the second agent in the coating composition kit according to any one of [1] to [4].

[6] A method for producing a paint composition, comprising the step of mixing at least the first agent and the second agent in the paint composition kit according to any one of [1] to [4].
[7] A coating film formed from the coating composition according to [5] above.

[8] A substrate with a coating film, comprising a substrate and the coating film according to [7] above.
[9] The substrate with a coating film according to the above [8], wherein the substrate is a steel material constituting a steel structure.

[10] A coated steel material comprising a steel material and the coating film according to the above [7] formed on a joint surface of a bolted joint of the steel material.

ADVANTAGE OF THE INVENTION According to this invention, the coating composition kit which can form the coating film which is excellent in the long-term storage stability, and is excellent in the slip coefficient in the bolted joint part of steel materials, for example can be provided.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below.
In this specification, the coating composition kit according to one embodiment of the present invention is also referred to as "the coating composition kit of the present embodiment", and the first agent and the second agent in the coating composition kit of the present embodiment are at least The coating composition obtained by mixing is also referred to as the "coating composition of the present embodiment", and the coating film formed from the coating composition of the present embodiment is also referred to as the "coating film of the present embodiment".

In this specification, the "slip coefficient" is measured based on "Appendix 7 Slip Coefficient Evaluation Test Method" of "Steel Structure Joint Design Guidelines" (3rd edition, Architectural Institute of Japan, 2012). slip coefficient

[Paint composition kit and paint composition]
The coating composition kit of this embodiment has a first agent and a second agent.
The first agent contains a siloxane-based binder (A), kaolin (B), and a pigment (C) having a Mohs hardness of 5 or more.

The second agent contains zinc powder (X).
The coating composition kit of the present embodiment is a packaged kit, and in one embodiment, it is a 1-liquid-1-powder type kit comprising a liquid first agent and a powdery second agent.

≪First Agent≫
In the present embodiment, since the first agent containing the siloxane-based binder (A) contains kaolin (B) and a pigment (C) having a Mohs hardness of 5 or more, zinc powder ( A step of mixing X) with kaolin (B) and a pigment (C) having a Mohs hardness of 5 or more and classifying is not required.
The first agent is preferably liquid.

<Siloxane-based binder (A)>
The first agent contains a siloxane-based binder (A). The siloxane-based binder (A) is usually a condensate of silicate, specifically a compound obtained by hydrolytic condensation of silicate.

Examples of the siloxane-based binder (A) include condensates of at least one compound (A1) selected from tetraalkoxysilanes and alkyltrialkoxysilanes, specifically the compound (A1) and/or or partial hydrolysis condensates of low condensates thereof.

Examples of the tetraalkoxysilane include tetramethylorthosilicate, tetraethylorthosilicate, tetra-n-propylorthosilicate, tetra-i-propylorthosilicate, tetra-n-butylorthosilicate and tetra-sec-butylorthosilicate. Examples of the alkyltrialkoxysilanes include methyltrialkoxysilanes such as methyltrimethoxysilane and methyltriethoxysilane.

Low condensates of the compound (A1) include, for example, low condensates of the tetraalkoxysilanes such as methylpolysilicate and ethylpolysilicate. A low condensate means a condensate having a degree of condensation of 2 to 20 (number of silicon atoms of 2 to 20).

The low condensate is preferably a low condensate of tetraethyl orthosilicate, and examples of the low condensate of tetraethyl orthosilicate include "ethyl silicate 45", "ethyl silicate 40" and "ethyl silicate 48" (Colcoat Ltd.), "Silicate 45" and "Silicate 40" (manufactured by Tama Chemical Industry Co., Ltd.), and "TES40WN" (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.). As the siloxane-based binder (A), a partially hydrolyzed condensate of Ethyl Silicate 40 (trade name; manufactured by Colcoat Co., Ltd.) is particularly preferred.

The weight average molecular weight (Mw) of the siloxane-based binder (A) contained in the first agent is usually 500-10,000, preferably 700-9,000, more preferably 800-5,000. When the Mw of the siloxane-based binder (A) is 500 or more, the drying property of the coating composition of the present embodiment is enhanced, and the coating film of the present embodiment tends to be enhanced in corrosion resistance. On the other hand, if the Mw of the siloxane-based binder (A) is 10,000 or less, the storage stability of the first agent is improved, and the coating composition of the present embodiment is applied to an excessively thick film. Film cracking tends not to occur easily.

The weight average molecular weight (Mw) of the siloxane-based binder (A) can be measured by a gel permeation chromatography (GPC) method. The value obtained by the GPC method is a value (polystyrene conversion value) determined using a calibration curve prepared using polystyrene as a standard substance.

The first agent can contain one or more siloxane-based binders (A).
The siloxane-based binder (A) can be produced using a conventionally known method. It can be produced by partial hydrolytic condensation reaction in the presence of a catalyst so that the weight average molecular weight (Mw) becomes a desired value.

Examples of the organic solvent include organic solvents described in the section <Organic Solvent> described later.
The amount of water to be used is generally 5 to 11 parts by mass, preferably 5.5 to 9 parts by mass, per 100 parts by mass of the compound (A1) and/or low condensates thereof.

Examples of catalysts include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid; formic acid; organic tin compounds such as dibutyltin dilaurate, dibutyltin dimaleate, dioctyltin dilaurate, dioctyltin dimaleate, dioctyltin maleate, and tin octylate; phosphoric acid or phosphoric acid esters such as phosphoric acid, monomethyl phosphate, monoethyl phosphate, monobutyl phosphate, monooctyl phosphate, monodecyl phosphate, dimethyl phosphate, diethyl phosphate, dibutyl phosphate, dioctyl phosphate, didecyl phosphate; Organic titanate compounds such as (acetylacetate) titanium and diisopropoxybis(ethylacetoacetate) titanium; organic aluminum compounds such as tris(ethylacetoacetate)aluminum and tris(acetylacetonate)aluminum; acetylacetonato)zirconium, tetraisobutylzirconate, and butoxytris(acetylacetonato)zirconium; Among these, inorganic acids are preferable, and hydrochloric acid is more preferable, because the storage stability of the first agent is good.

When a catalyst is used, the amount used is usually 0.01 to 2.0 parts by mass, preferably 0.02 to 1.0 part by mass, per 100 parts by mass of the compound (A1) and/or low condensates thereof. It is 0 parts by mass.

A boron compound, which will be described later, can be used during the production of the siloxane-based binder (A). By introducing a structure derived from a boron compound into the siloxane-based binder (A), the drying curability of the coating composition of the present embodiment can be improved.

Boron compounds include, for example, boric acid and boron trioxide.
When a boron compound is used, the amount used is usually 0.3 to 11 parts by weight, preferably 1.5 to 7 parts by weight, per 100 parts by weight of the compound (A1) and/or low condensate thereof. is.

The content ratio of the siloxane-based binder (A) is obtained by converting the mass of the siloxane-based binder (A) into the mass of SiO ₂ (that is, the mass of the siloxane-based binder (A) is calculated as the siloxane-based binder ( (Converted to the mass of SiO ₂ equivalent to the amount (mol) of Si atoms contained in A)), and when the solid content of the coating composition of the present embodiment is 100% by mass, it is usually 1 to 15% by mass. , preferably 2 to 10% by mass, more preferably 3 to 8% by mass.

In addition, the content ratio of the siloxane-based binder (A) is obtained by converting the mass of the siloxane-based binder (A) into the mass of SiO ₂ (that is, the mass of the siloxane-based binder (A) is converted to the siloxane-based bond When the solid content of the first agent is 100% by mass (converted into the mass of SiO ₂ equivalent to the amount (mol) of Si atoms contained in the agent (A)), it is usually 10 to 70% by mass, preferably is 20 to 60% by mass, more preferably 30 to 50% by mass.

When the content of the siloxane-based binder (A) is within the above range, the coating film of the present embodiment is excellent in corrosion resistance, crack resistance, and adhesion to a substrate.
In addition, the solid content of the coating composition or the first agent of the present embodiment means the residue (heating residue). The heating residue of the coating composition and the first agent can be measured according to JIS K 5601 1-2 (heating temperature: 125° C., heating time: 60 minutes).

The hydrolysis rate of the siloxane-based binder (A) is preferably 35-75%, more preferably 38-55%. When the hydrolysis rate of the siloxane-based binder (A) is within the above range, it is possible to obtain a first agent having more excellent storage stability, and to improve the drying property and the thickness of the film. It is possible to obtain a coating composition which is also more excellent in crack resistance.

When the siloxane-based binder (A) is a partially hydrolyzed condensate of the compound (A1) and/or a low condensate thereof, the hydrolysis rate (%) is the It means the reaction rate of the reactive group (alkoxy group) contained in the low condensate, and can be calculated by the following formula 1.

Hydrolysis rate (%) = (W / 18 × 2 / (S / E)) × 100 (Formula 1)
In Formula 1, W is the mass (g) of water used in preparing the siloxane-based binder (A), S is the mass (g) of tetraalkoxysilane, alkyltrialkoxysilane and the low condensate, and E is the reactive group equivalent weight of tetraalkoxysilane, alkyltrialkoxysilane and said low condensate.

<Kaolin (B)>
The first agent contains kaolin (B). Although the reason is not clear, when a pigment (C) having a Mohs hardness of 5 or more is included in the first agent containing the siloxane-based binder (A) in order to improve the slip coefficient of the coating film, the long-term storage stability is improved. By further including kaolin (B) in the first agent, the first agent exhibits excellent long-term storage stability, and the kneadability between the first agent and the second agent is improved. As a result, stable supply of the coating composition becomes possible. Indices of storage stability here include, for example, pigment sedimentation and/or gelation.

Kaolin (B) is a layered inorganic pigment usually produced from naturally occurring clay (mineral name: kaolinite (chemical formula: Al ₂ O ₃ .2SiO ₂ .2H ₂ O)). Kaolin (B) usually has a scaly, thin, flat shape. Kaolin (B) is not particularly limited, but examples thereof include wet kaolin, dry kaolin, and calcined kaolin.

The median diameter of kaolin (B) is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm. As used herein, the median diameter is measured by a laser diffraction method.

The first agent can contain one or more kaolins (B).
The content of kaolin (B) is usually 5 to 80% by mass, preferably 10 to 50% by mass, based on 100% by mass of the solid content of the first agent. When the content of kaolin (B) is 5% by mass or more, the storage stability of the first agent tends to be better. The coefficient tends to be difficult to decrease.

The content of kaolin (B) is preferably 0.5 to 15% by mass, more preferably 1 to 10% by mass, based on 100% by mass of the solid content of the coating composition of the present embodiment.

<Pigment (C) with Mohs hardness of 5 or more>
The first agent contains a pigment (C) having a Mohs hardness of 5 or more (hereinafter also referred to as "pigment (C)"). By containing the pigment (C) in the first agent, the slip coefficient of the coating film of the present embodiment is increased.

The Mohs hardness of the pigment (C) is 5 or more, preferably 5 or more and 8 or less, more preferably 5.5 or more and less than 7.5. Mohs hardness can be measured according to a 10-step Mohs hardness scale.

Examples of the pigment (C) include iron oxides such as yellow iron oxide, red iron oxide and black iron oxide; feldspars such as potassium feldspar, orthoclase, microcline feldspar, albite and anorthite; silica and pumice. Yellow iron oxide, potassium feldspar, and silica are preferred from the viewpoint of high slip coefficient and excellent storage stability.

The shape of the pigment (C) is not particularly limited, but various shapes such as spherical, needle-like, plate-like, scale-like, and fiber-like can be used. In one embodiment, the median diameter of pigment (C) is from 0.1 to 50 μm.

Yellow iron oxide is usually acicular particles. The median diameter of yellow iron oxide is preferably 0.1 to 30 μm, more preferably 0.2 to 20 μm.
Potassium feldspar is usually a particle with shell-like fractures obtained by pulverizing orthoclase. The median diameter of potassium feldspar is preferably 1 to 50 μm, more preferably 2 to 30 μm.

As silica, fine powder silica having an average primary particle size of 1 μm or less is preferable. The finely divided silica preferably has an average primary particle size of 5 to 100 nm. The specific surface area of finely divided silica is preferably 50 m ² /g or more. The finely divided silica may be surface-treated or untreated. In the present specification, the average nano-sized primary particle diameter is the average number of major diameters of primary particles observed with an electron microscope.

In one embodiment, from the viewpoint of the slip coefficient of the coating film, the pigment (C) preferably contains finely divided silica, more preferably yellow iron oxide and/or potassium feldspar, and finely divided silica.

The first agent can contain one or more pigments (C).
The content of the pigment (C) is usually 5 to 70% by mass, preferably 10 to 50% by mass, based on 100% by mass of the solid content of the first agent. When the content of the pigment (C) is 5% by mass or more, the slip coefficient of the coating film of the present embodiment tends to be high. It tends to be difficult to decrease.

The content of the pigment (C) is preferably 1 to 10% by mass, more preferably 2 to 6% by mass, based on 100% by mass of the solid content of the coating composition of the present embodiment.

<Curing accelerator (D)>
The first agent can contain a curing accelerator (D).
Examples of the curing accelerator (D) include boric acid, boron compounds such as boron trioxide, oxalic acid, ferric chloride, and zinc chloride. Among these, boron compounds such as boric acid and boron trioxide are preferable from the viewpoint of storage stability and crack resistance.

The curing accelerator (D) acts, for example, as a curing catalyst when curing the coating composition applied on the substrate to form a coating film.
The first agent can contain one or more curing accelerators (D).

When the curing accelerator (D) is used, its content is preferably 0.1 to 10% by mass, more preferably 1 to 5% by mass, based on 100% by mass of the solid content of the first agent. When the content of the curing accelerator (D) is within the above range, the storage stability of the siloxane-based binder (A) is improved, and the drying property and crack resistance of the coating film of the coating composition of the present embodiment are also improved. tend to be superior.

<Organic resin (E)>
The first agent may contain an organic resin (E) other than the siloxane-based binder (A) as long as the objects and effects of the present invention are not impaired. Examples of the organic resin (E) include butyral resins such as polyvinyl butyral resins, and acrylic resins.

Examples of polyvinyl butyral resins include S-Lec BM-1, S-Lec BM-2, and S-Lec BL-1 (trade name; manufactured by Sekisui Chemical Co., Ltd.). Examples of acrylic resins include Dianal BR-106 ( trade name; manufactured by Mitsubishi Chemical Corporation).

The first agent can contain one or more organic resins (E).
When the organic resin (E) is used, its content is preferably 0.00% in 100% by mass of the solid content of the first agent, from the viewpoint of suppressing the coating workability of the coating composition and cracking resistance of the coating film. 1 to 10% by mass, more preferably 0.5 to 8% by mass.

<Thickener (F)>
The first agent can contain a generally known thickening agent (F). The thickener (F) can improve the kneadability of the first agent and the second agent described later.

As the thickener (F), conventionally known thickeners can be used without limitation. Examples of the thickener (F) include organic thickeners such as polyamide wax, polyethylene wax, and oxidized polyethylene wax; system thickeners.

The first agent can contain one or more thickening agents (F).
When the thickener (F) is used, its content is preferably 0.05 to 5% by mass, more preferably 0.1 to 3% by mass in 100% by mass of the solid content of the coating composition of the present embodiment. %.

<Organic solvent>
The first agent usually contains an organic solvent for diluting, improving storage stability, improving pot life, and the like.

Examples of the organic solvent include at least one organic solvent (S1) selected from glycol ether solvents, ketone solvents, and acetate solvents. Compared with the first agent containing no organic solvent (S1), the first agent containing the organic solvent (S1) improves the storage stability of the siloxane-based binder (A). It is presumed that this is because the silanol groups that the siloxane-based binder (A) may have are stabilized by hydrogen bonding with the oxygen atoms of the organic solvent (S1), and the condensation reaction is suppressed.

Examples of glycol ether solvents include propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, with propylene glycol monomethyl ether being preferred. Examples of ketone-based solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, with methyl ethyl ketone being preferred. Examples of the acetate solvent include ethyl acetate and butyl acetate, with ethyl acetate being preferred. Among these, glycol ether solvents are preferable, and propylene glycol monomethyl ether is more preferable.

The first agent can contain one or more organic solvents (S1).
The first agent may contain an organic solvent (S2) other than the organic solvent (S1) for the purpose of adjusting the drying property of the coated composition.

Examples of the organic solvent (S2) include organic solvents commonly used in the paint field, such as alcohol solvents, aromatic solvents, and cellosolve solvents. Examples of alcohol solvents include methanol, ethanol, isopropanol, and butanol. Examples of aromatic solvents include benzene, xylene, and toluene. Cellosolve solvents include, for example, methyl cellosolve, ethyl cellosolve, and butyl cellosolve.

The first agent can contain one or more organic solvents (S2).
The content of the organic solvent in the first agent is not particularly limited, but is usually 10 to 80% by mass, preferably 25 to 60% by mass.

<Preparation of first agent>
The first agent includes, for example, a siloxane-based binder (A), kaolin (B), a pigment (C) having a Mohs hardness of 5 or more, and optionally the components (D) to (F) described above, an organic solvent, and the like. Obtained by mixing.

≪Second agent≫
<Zinc powder (X)>
The second agent contains zinc powder (X). The zinc powder (X) is not particularly limited in shape, size, etc., and conventionally known powders in the field of coatings can be used.

The zinc powder (X) includes, for example, metallic zinc powder and zinc alloy powder. Zinc alloys include, for example, alloys of zinc and at least one selected from aluminum, magnesium and tin. The shape of the particles constituting the zinc powder (X) includes various shapes such as a spherical shape and a scaly shape.

The median diameter of zinc powder (X) is 1 to 30 μm.
The second agent can contain one or more zinc powders (X).
The content of the zinc powder (X) is usually 30 to 98% by mass, preferably 50 to 97% by mass, more preferably 65 to 95% by mass in 100% by mass of the solid content of the coating composition of the present embodiment. be. When the content of the zinc powder (X) is within the above range, the coating film of the present embodiment is excellent in rust prevention over a long period of time. Therefore, the coating composition of this embodiment is useful as a so-called inorganic zinc-rich paint.

≪Other ingredients≫
The first agent and/or the second agent or the coating composition of the present embodiment contains a pigment dispersant, an extender pigment other than kaolin (B) and the pigment (C), and a coloring agent for the purpose of ensuring various coating film properties. Other ingredients such as pigments, anti-corrosion pigments, adhesion promoters, etc. may be further included. Other components may be used individually by 1 type, and may use 2 or more types together.

[Usage form of paint composition kit, method for producing paint composition]
In one embodiment, the paint composition kit of the present embodiment is such that the paint manufacturer manufactures the first agent and the second agent and separately provides them to the painter, and the painter manufactures the first agent and the second agent. are mixed before coating, and the resulting coating composition is applied. In addition, the coating composition kit of the present embodiment may further include a third agent or the like containing at least one component selected from the components described above, for example.

In this embodiment, kaolin (B) and pigment (C) are included in the first agent. When these pigments are included in the second agent containing the zinc powder (X), a process of mixing and classifying the pigment powder is required, and a process of classifying the powders after storage may be required. In one aspect, this embodiment does not require a step of mixing zinc powder (X), kaolin (B), pigment (C), etc. in the second agent, or a step of classifying, thereby simplifying the manufacturing process. can.

The coating composition of the present embodiment can be obtained by mixing at least the first agent and the second agent in the coating composition kit of the present embodiment. For example, the first agent and the second agent are sufficiently stirred and homogenized using a stirrer.

The coating composition of this embodiment is excellent in drying property. By using the coating composition, it is possible to form a coating film which is excellent in corrosion resistance and crack resistance in a thick film and has a high slip coefficient.

The coating film of this embodiment is formed from the coating composition of this embodiment, and is useful as an anticorrosion/rust prevention coating film. The substrate with a coating film of the present embodiment has a substrate and the coating film of the present embodiment. For example, the coating film of the present embodiment and the substrate with the coating film can be obtained by coating the coating composition of the present embodiment on the substrate surface and curing the composition.

Examples of the base material include conventionally known base materials such as steel materials. Specific examples include ship structures such as ships, civil engineering structures such as bridges and tanks, plant structures such as oil drilling plants, and pipes. steel structures such as lines; architectural structures such as houses and buildings; outdoor equipment such as guard fences and industrial machinery. The coating composition of the present embodiment is applied as the first anticorrosive coating on the surface of these substrates. Generally, the substrate to which the coating composition of the present embodiment is applied is subjected to blasting under conditions corresponding to a rust removal degree Sa2 1/2 or more in ISO 8501-1. In addition, if necessary, a primer coating, an intermediate coating and a top coating are applied onto the coating film obtained from the coating composition of the present embodiment.

In one embodiment, the base material specifically includes a steel material that can be bolted, and the coating composition of the present embodiment is applied to the joint surface of the bolted joint of the steel material. In this joint surface, no other paint is applied onto the coating film coated with the coating composition of the present embodiment, and the joint surfaces coated with the coating film composed of the coating composition of the present embodiment are joined. As a result, a frictional force with a slip coefficient of 0.5 or more is exerted.

Examples of methods for applying the coating composition of the present embodiment include air spray and airless spray. The method for curing the coating composition after coating is not particularly limited, and conventionally known curing methods can be applied. For example, when the coating composition applied to the substrate is left in the air (with heating if necessary), the solvent volatilizes, and the siloxane-based binder (A) becomes water or air in the coating composition. It is cured by a hydrolytic condensation reaction caused by the moisture (humidity) inside. In one embodiment, the coating conditions are typically 5-40°C.

The average dry film thickness of the coating film of the present embodiment is preferably 40 μm or more, more preferably 40 to 120 μm. The average dry film thickness of the coating film may be less than 40 μm, which is a thin film, depending on the state and application of the substrate to be coated. In addition, when the coating film of the present embodiment is a thick film having an average dry film thickness exceeding 120 μm, for example, even if it is more than 120 μm and 200 μm or less, it is excellent in crack resistance.

The slip coefficient of the coating film of the present embodiment is preferably 0.5 or more, more preferably 0.55 or more, and the upper limit is not particularly limited, but may be 0.8. With a coating film having a slip coefficient as high as 0.5 or more, for example, when bolting joints, for safety reasons, there is no need to increase the size of reinforcing materials such as splice plates used in joints of steel materials, and bolts to be tightened Since there is no need to increase the number, it is preferable in terms of work cost.

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited only to these examples. In the following description, "parts by mass" are described as "parts" unless otherwise specified.

The details of each component described in the table are as follows.
・ Alkyl silicate “Ethyl Silicate 40”: manufactured by Colcoat Co., Ltd. ・ Zinc powder “F-500”: manufactured by Honjo Chemical Co., Ltd. ・ Kaolin “ASP 200”: manufactured by BASF Japan Co., Ltd. ・ Talc “FC-1 talc” : Mica “Mica powder 325 mesh” manufactured by Fukuoka Talc Kogyo Co., Ltd. : Calcium carbonate “Carfine 200M-C” manufactured by Fukuoka Talc Kogyo Co., Ltd. Yellow iron oxide “TSY-” manufactured by Maruo Calcium Co., Ltd. 1”: Potassium feldspar “UNISPAR PG-K10” manufactured by Toda Kogyo Co., Ltd.:
Sibelco Malaysia Sdn Bhd ・Micronized silica “AEROSIL R972”: Nippon Aerosil Co., Ltd. ・Acrylic resin “Dianal BR-106”: Mitsubishi Chemical Co., Ltd. ・Polyvinyl butyral resin “S-Lec BM-2”: Sekisui Chemical Co., Ltd. Polyamide wax "Disparon A630-20X": Kusumoto Kasei Co., Ltd. Organic bentonite "BENTONE SD-2": Elementis Specialties, Inc.; Made

[Preparation example]
28.00 parts of ethyl silicate 40, 39.42 parts of propylene glycol monomethyl ether (PGM), 6.92 parts of ethanol (technical ethanol), 1.56 parts of deionized water, and 0 as catalyst. 10 parts of 35% hydrochloric acid was charged into the container (1), and 1.00 parts of boron trioxide was further charged into the container (1), stirred at 25°C for 1 hour and 30 minutes, and allowed to cool for 16 hours. .

Furthermore, 1.00 parts of an acrylic resin and 5.00 parts of xylene were charged in another container (2) and stirred at 25° C. for 30 minutes to prepare an acrylic resin varnish.
Next, 10.00 parts of kaolin, 6.00 parts of yellow iron oxide, and 1.00 parts of finely powdered silica are charged into the vessel (1) which has been allowed to cool for 16 hours while stirring at 25°C, Finally, 6.00 parts of the acrylic resin varnish prepared in advance in the container (2) was added and stirred at 25° C. until uniform, to prepare the first agent (I-1).

Furthermore, the same operation as for the preparation of the first agent (I-1) was performed except that the types and amounts of each raw material were changed as shown in Tables 1-1 and 1-2, and the first agent (I- 2) to (I-16) and (cI-1) to (cI-4) were prepared.

<Weight average molecular weight (Mw) of siloxane-based binder (A)>
Weight-average molecular weight of the siloxane-based binder (A) in the first agent (I-1) to (I-16) and (cI-1) to (cI-4) at the initial stage (about one day after preparation) (Mw) was measured by a gel permeation chromatography (GPC) method.

The measurement conditions of GPC are as follows. A small amount of each of the first agents was taken and diluted with tetrahydrofuran, and the resulting solutions were filtered through a membrane filter to obtain samples for GPC measurement.
・Equipment: 2695 separation module manufactured by Nippon Waters Co., Ltd.
(Alliance GPC Multisystem)
・Column: TSKgel Super H4000 manufactured by Tosoh Corporation
TSKgel Super H2000
TSKgel Super H2000
Measured by connecting the above three wires in series.
・ Eluent: Tetrahydrofuran (THF)
・Flow rate: 0.6 ml/min ・Detector: Shodex RI-104
・Column bath temperature: 40°C
・Standard material: polystyrene

<Hydrolysis rate of siloxane-based binder (A)>
The hydrolysis rate of the siloxane-based binder (A) was calculated based on Formula 1 described above.

[Examples 1 to 16, Comparative Examples 1 to 4]
The second agent and the first agent stored at 23 ° C. for 1 month after preparation were placed in a polyethylene container at the ratios (parts by mass) shown in Tables 1-1 and 1-2, and 10% with a high speed disper. A minute dispersion treatment was performed to prepare a coating composition.

[Evaluation test]
<Storage stability>
Regarding the first agents (I-1) to (I-16) and (cI-1) to (cI-4) obtained in Preparation Examples, the state after storage at 23 ° C. for 12 months is shown in Table 2. was evaluated for storage stability.

In addition, the siloxane-based binder (A) in the first agent (I-1) to (I-16), (cI-1) to (cI-4) after 1 month, 6 months and 12 months at 23 ° C. The weight average molecular weight (Mw) of was measured by the GPC method.

<Drying property>
Each coating composition obtained in Examples and Comparative Examples was applied to a sandblasted steel plate (150 mm × 70 mm × 2.3 mm, Sa2 1/2 or more) with an air spray so that the dry film thickness was 75 µm, and the temperature was 25 ° C. , While drying under the conditions of 70% relative humidity, rub the coating film 50 times with methyl ethyl ketone (MEK) every hour to measure the time until the coating film does not dissolve, and dry according to the criteria shown in Table 2. evaluated the sex.

<Corrosion resistance>
Each coating composition obtained in Examples and Comparative Examples was applied to a sandblasted steel plate (150 mm × 70 mm × 2.3 mm, Sa2 1/2 or more) with an air spray so that the dry film thickness was 75 µm, and the temperature was 25 ° C. , Dry for 7 days at 70% relative humidity to create a test coated board, and expose it to the outdoors (Otake City, Hiroshima Prefecture) for 2 years. The degree of occurrence was evaluated according to the criteria shown in Table 2.

<Crack resistance>
Each coating composition obtained in Examples and Comparative Examples was applied to a sandblasted steel plate (150 mm × 70 mm × 2.3 mm, Sa2 1/2 or more) with an air spray so that the dry film thickness was 200 µm, and the temperature was 25 ° C. , and 70% relative humidity for 7 days to prepare a coated plate for crack resistance test.

<Slip coefficient>
On both sides of the grid blasted SM490 plate, each coating composition obtained in Examples and Comparative Examples was applied by air spray so that the dry film thickness was 75 μm, dried for 1 month, and subjected to a coating test. got a body The prepared coated specimen was tightened with a Torsia-type high-strength TC bolt (M22), and the slip coefficient was measured using a tensile tester and evaluated according to the criteria shown in Table 2.

Claims (10)

a liquid first agent containing a siloxane-based binder (A), kaolin (B), and a pigment (C) having a Mohs hardness of 5 or more;
A coating composition kit having a powdery second agent containing zinc powder (X). The coating composition kit according to claim 1, wherein the siloxane-based binder (A) has a weight average molecular weight (Mw) of 500 to 10,000. The coating composition kit according to claim 1 or 2, wherein the siloxane-based binder (A) is a condensate of at least one compound (A1) selected from tetraalkoxysilanes and alkyltrialkoxysilanes. The coating composition kit according to any one of claims 1 to 3, wherein the pigment (C) contains at least one selected from yellow iron oxide, potassium feldspar and silica. A paint composition obtained by mixing at least the first agent and the second agent in the paint composition kit according to any one of claims 1 to 4. A method for producing a paint composition, comprising a step of mixing at least the first agent and the second agent in the paint composition kit according to any one of claims 1 to 4. A coating film formed from the coating composition according to claim 5 . A coated substrate comprising a substrate and the coating according to claim 7 . 9. The coated base material according to claim 8, wherein the base material is a steel material constituting a steel structure. A coated steel material comprising a steel material and the coating according to claim 7 formed on a joint surface of a bolted joint of the steel material.