JPH0356577A - Silicon alkoxide-based coating material - Google Patents

Abstract

PURPOSE:To obtain the subject coating material, composed of a combination of a principal component solution, containing a silicon alkoxide and a curing solution containing a curing agent, curable at ordinary temperature, capable of providing films excellent in weather resistance and hardness and designed to be blend an alumina sol and acidic catalyst as a catalyst. CONSTITUTION:The objective coating material, composed of a combination of a principal component solution containing at least a silicon alkoxide [prefer ably expressed by the formula (n is 0-3; R<1> is 1-4C alkyl, phenyl, etc.; R<2> is 1-4C alkyl) and composed of 20-200 pts. wt. silicon compound in which n is 0 and/or colloidal silica, 100 pts. wt. silicon compound in which n is 0 and 0-80 pts. wt. silicon compound in which (n) is 2] with a curing solution containing at least a curing agent (e.g. water) and designed to blend an alumina sol and an acidic catalyst (e.g. hydrochloric acid) as a catalyst therewith. Furthermore, the amount of the alumina sol is preferably 0.1-0.6 wt.%.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to inorganic paints, particularly silicon alkoxide coating agents that contain silicon alkoxide as a main component and form coating films with excellent weather resistance and hardness. Regarding. [Prior Art] Silicon alkoxide coating agents are weather resistant and provide a highly hard coating film, so for example,
JP-A-51-2736 and JP-A-56-125
Various studies have been conducted as shown in Publication No. 466 and the like.

[Problem to be solved by the invention]

However, these conventional silicon alkoxide coating agents require heating (usually
(requires a temperature of 100℃ or higher). For this reason, the scope of use of silicon alkoxide coating agents is currently limited.

Therefore, the present invention has developed a silicon alkoxide coating agent that can form a coating film even when baked without impairing the characteristics of the silicon alkoxide coating agent, which is that it forms a coating film with excellent weather resistance and hardness. The challenge is to provide.

[Means to solve the problem]

In order to solve the above problems, the silicon alkoxide coating agent according to the present invention consists of a combination of a main liquid containing at least a silicon alkoxide and a curing liquid containing at least a curing agent, and uses an alumina sol and an acidic catalyst as a catalyst. is now being blended.

Silicon alkoxide, which is an essential component (or main raw material) of the main component liquid separation, is, for example, represented by the following general formula.

R'nS i (OR")a-...■
■In the formula, n is 0 to 3, and R' is a monovalent group such as an alkyl group having 1 to 4 carbon atoms, or a phenyl group (these may include an ξ group, an acrylic group, etc.) The group R2 is an alkyl group having 1 to 4 carbon atoms. When there are a plurality of Rl and Rl, all R' or R1 may be the same group, or one or more may be different.

Furthermore, in order to obtain a more stable coating film, (a) a silicon compound and/or colloidal silica represented by the case where n=o in the above general formula is added to
~200 parts by weight (hereinafter, "parts by weight" is simply referred to as "parts", (bl) 100 parts of a silicon compound represented by the case where n=1 in the above general formula, (e) n= in the above general formula Preferably, the silicon compound is composed of 0 to 80 parts of each of the precepts represented in case 2.

The main component liquid is made by adding a curing agent and a catalyst in a stoichiometrically insufficient amount (for example, a very insufficient amount) to silicon alkoxide to produce a silicon alkoxide-based prepolymer (a hydrolyzed or condensed product of silicon alkoxide). (terminal alkoxide). Examples of the curing agent and catalyst used here include those described below. The molecular weight of the prepolymer is not particularly limited, but preferably has an Mw (weight average molecular weight, calculated as boristyrene) of 200 to 600. The main component liquid is
In addition, depending on the purpose, colloidal silica, inorganic filler, pigment (inorganic pigment and/or organic pigment f4),
One or more of various additives such as diluting solvents, thickeners, surfactants, etc. may be added. However, be careful that there is no residual moisture in the main or separated liquid.

The main component liquid prepared as described above has a solid content concentration of 10 to 50 wt%, for example.

The curing liquid has a hardening agent as an essential component, and other various components as necessary, such as a catalyst, a diluting solvent, and colloidal silica.
More than one species may be blended.

The curing agent is not particularly limited, but water is used, for example. The blending ratio of the curing agent is not particularly limited; The amount is set as necessary to form a film.

The catalyst used in this invention is an alumina sol and an acidic catalyst. The alumina sol is not particularly limited as long as it is a colloidal alumina dispersed in a solvent, but examples include r#100J and r#200 manufactured by Nissan Chemical Industries, Ltd.
J, r#520L1, etc., rAS-IJ, rAS-2J, rAS-3J, etc. manufactured by Catalyst Kawei Kogyo Co., Ltd. can be used.

Examples of solvents for alumina sol include water. Further, the acidic catalyst is not particularly limited, but for example,
Examples include dilute solutions of non-acid acids such as hydrochloric acid, phosphoric acid, and sulfuric acid, and organic acids such as formic acid, acetic acid, and chloroacetic acid, and they can be used alone or in combination. As the acidic catalyst, it is also possible to use solid acids such as inorganic oxides.

The amount of Almuro Nazol added is not particularly limited, but the solid content is 0.00% relative to the entire coating agent. 1~0. 6% by weight
It is preferable to set the ratio to . If it is less than 0.1% by weight,
Room temperature curability may not be exhibited, and if it exceeds 0.6% by weight, the coating performance may deteriorate. In addition, one type of alumina sol may be used alone, but
It is preferable that two or more kinds of alumina sols are used in combination, and the two or more kinds of alumina sols are acidic sols having different pH values. Here, the acidic alumina sols having different pH values are, for example, one with a pH of less than 4.0 and one with a pH of less than 4.0.
It is best to use it in combination with 5 or more. If only a sol with a pH value of less than 4.0 is used, the usable time (pot life) of the paint after mixing the two components may be shortened, and if the pH value is less than 4.5,
The above-mentioned sols alone may be difficult to exhibit room-temperature curability. Also, pH 4. Even if the sol has a molecular weight of 0 or more and less than 4.5, it may be difficult to exhibit room-temperature curability. The addition ratio (weight ratio) of the sol having a pH value of less than 4.0 to the sol having a pH value of 4.5 or more is preferably 50 to 10 sol having a pH value of 4.5 or more.

Further, as the curing liquid, it is preferable to use one containing a diluting solvent. When added with only water and catalyst,
This is because there is a risk that pigments and the like will re-agglomerate.

Examples of the diluting solvent include alcohols such as methanol, ethanol, and isopropanol (IPA), ethylene glycol, and ethylene glycol monomethyl ether, which may be used alone or in combination. In the silicon alkoxide coating agent of the present invention, the main component liquid and the curing liquid are two liquids before use, and at the time of use,
The main liquid, curing liquid, and other ingredients added as necessary are mixed, aged as necessary, and then used for painting. The coating method is not particularly limited, and examples thereof include spray coating, roll coating, flow coater coating, and dipping coating. After painting, a coating film with excellent weather resistance and hardness is formed by, for example, being allowed to stand at room temperature for an appropriate period of time. Therefore, there is no need to perform baking. Therefore, the silicon alkoxide coating agent of the present invention can be used in a wider range of applications than conventional coating agents that require baking. Kata precept is maintained. And when using,
The main component liquid containing at least silicon alkoxide is mixed with a curing liquid containing at least a curing agent, and an alumina sol and an acidic catalyst are added as catalysts to cure at room temperature. If only alkali nazol is used as a catalyst, the amount added is too large in order to exhibit room temperature curability, leading to deterioration of coating film performance. Furthermore, if only an acidic catalyst is used as a catalyst, the OpH value of the coating agent will be very low, which will limit its use.

〔Example〕

Specific examples and comparative examples of the present invention are shown below, but the present invention is not limited to the following examples.

Examples 1 to 5 and Comparative Examples 1 to 3 Coating: 100 parts of methyltrimethoxysilane, 5 parts of tetraethoxysilane, IPA silica sol (rOscAL1432J manufactured by Catalyst Kakai Kogyo Co., Ltd., SiO, content 30%) 60
parts, 20 parts of dimethyldimethoxysilane, and IPA
20 parts were mixed.

To this mixed solution, 0.85 part of 1N hydrochloric acid as a catalyst,
Then, add 5 parts of water as a hardening agent and 500O at 25℃.
Solution A was prepared by stirring at rpm+ for 30 minutes.

After storing Solution A in a tightly closed container at 25°C for 24 hours, add 20 parts of titanium oxide (dioxide) and "Turen KY-2000J (manufactured by Kyoeisha Yushigaku Kogyo Co., Ltd.) to 100 parts of Solution A. Added 0.3 part of solid content and 0.3 part of "ETCEL STD-1004 (manufactured by Dow Kashu Cal), and added 0.3 part of "Floren G-600".
0.5 part of J (manufactured by Kyoeisha Yushi Kagaku Kogyo Co., Ltd.) was added, glass beads were added into the container, and the mixture was stirred for 15 minutes at 2000 rpm using a disper.Then, it was placed in a tightly sealed container and heated to 72°C at 25°C. After storing for a while, solution B was prepared.

When using, 26 parts of water and 26 parts of IPA for 100 parts of liquid B.
10 parts of IPA silica sol, 0.2 parts of 1N hydrochloric acid as a catalyst, and alumina sol manufactured by Nissan Chemical Industries, Ltd. in the proportions shown in Table 1, and heated at 25°C at 500 rpm.
After stirring at a+ for 1θ minutes, the mixture was left to stand for 1 hour, and the curing property at room temperature was examined.

The weight average molecular weight (polystyrene equivalent) of Brevolimer in liquid A of each coating agent of the above examples and comparative examples was determined by GPC (gel permeation chromatography: Toyo Soda ■
As a result of the investigation, they were both 200 to 400. The pH of the silicon alkoxide coating agent after all the raw materials were mixed, the pot life after mixing the two components, and the room temperature curability (touch dry time, hot water resistance, and hardness) were investigated, and the results are shown in Table 1. Ta. The pot life after mixing the two components was expressed as the usable time of the coating agent in an atmosphere of 20°C. The drying time to the touch was determined by measuring the time it took for the material to become tackless when lightly touched with the finger, in accordance with the JIS method. Hot water resistance was determined by spray coating each of the coating agents of Examples and Comparative Examples on an alumina substrate at room temperature to a film thickness of IQ,n, and leaving it for one week to evaluate the coating film shape. Thereafter, the condition of the coating film after being immersed in warm water (temperature 60°C) for 10'EI was examined with the naked eye. The hardness was determined by conducting a JIS pencil hardness test on a coating film formed in the same manner as when testing hot water resistance.

As shown in Table 1, each of the coating agents of Examples 1 to 5 was cured at room temperature, and had good hot water resistance and hardness. The comparative example did not cure at room temperature.

〔Effect of the invention〕

As described above, the silicon alkoxide-based coating agent according to the present invention is composed of a combination of a main liquid containing at least silicon alkoxide and a curing liquid containing at least a curing agent, and includes an alumina sol and an acidic catalyst as a catalyst. It is formulated so that it cures at room temperature. Therefore, this coating agent can produce a coating film with excellent weather resistance and hardness without baking.

Claims (1)

[Claims] 1. A main component liquid containing at least silicon alkoxide;
A silicon alkoxide coating agent, which is composed of a curing liquid containing at least a curing agent, and contains an alumina sol and an acidic catalyst as a catalyst. 2. The silicon alkoxide coating agent according to claim 1, wherein the solid content of the alumina sol is 0.1 to 0.6% by weight based on the entire coating agent. 3. The silicon alkoxide coating agent according to claim 1 or 2, wherein two or more types of alumina sols are blended, and the two or more types of alumina sols are acidic sols having different pH values.