JPH03182572A - Coating composition and method for coating therewith - Google Patents

Abstract

PURPOSE:To provide a coating compsn. useful for coating a molded cement article, etc., and excellent in storage stability, weatherability, and resistance to heat, abrasion, and chemicals by compounding a hydrolyzate of a metal alkoxide with a mixture of an inorg. filler and an org. filler. CONSTITUTION:A coating compsn. for a molded cement article, etc., prepd. by compounding a hydrolyzate of metal alkoxide (e.g. alkoxysilane) with a mixture of an inorg. filler (e.g. zircon, zirconia, silica, talc, titania, mica, glass, graphite, or stainless steel) with an org. filler (e.g. ethylene-vinyl acetate copolymer, fluororesin, acrylonitrile-vinylidene chloride copolymer, or silicone resin). The org. filler is compounded in an amt. of 1-15wt.%, pref. 2-10wt.% of the total coating compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a coating material and a coating method using the same. More specifically, the present invention relates to a coating material for cement molded articles and the like that has high storage stability and excellent weather resistance, heat resistance, abrasion resistance, and chemical resistance, and a method for coating the same.

(Conventional technology and its issues) Various surface coatings have been applied to cement molded products such as concrete, mortar, cement, and slate in order to improve their durability and design. There is an increasing demand for surface coatings to prevent concrete structures from being damaged by salt, carbonation, deterioration due to chemicals, or deterioration due to alkaline aggregate reactions. In addition, in recent years, civil engineering 41! There is a trend to apply surface coatings to structures to improve the aesthetic appearance of the entire city, and from this point of view, there is a strong desire to realize surface coatings with excellent durability.

As coating materials for forming such relatively durable surface coatings, coating materials containing inorganic fillers are already known.

However, this conventional coating material has the problem that sufficient water resistance and alkali resistance cannot be obtained unless heat treatment is performed after coating, which inevitably reduces workability on site. Furthermore, since the inorganic filler is likely to precipitate and become cakey, storage stability is poor, and thick film coating is also difficult. For this reason, coating materials containing inorganic fillers are actually only used for some secondary products of molded products, and are widely used for all molded products such as cement, including architectural structures and civil engineering artifacts. It was never used.

This invention was made in light of the above circumstances, and it improves the drawbacks of conventional coating materials, has high storage stability, and has excellent weather resistance, sharpness, abrasion resistance, and chemical resistance. The object of the present invention is to provide a covering material for cement-based, wood-based and metal-based moldings that is excellent in construction and easy to apply, and a method for covering the same.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a coating material characterized by blending a mixture of an inorganic filler and an organic filler with a hydrolyzate of a metal alkoxide. provide.

Further, in a preferred embodiment of the present invention, the blending ratio of the organic filler is 1 to 15 wt% of the total amount of the coating material.

Furthermore, the present invention also provides a method of coating a cement molding, a wood material, or a metal molding using such a coating material.

As the metal alkoxide hydrolyzate in this invention, a metal alkoxide represented by the general formula M (OR>) can be hydrolyzed. Examples of the metal alkoxide in this case include alkoxysilane, alkoxyzirconium, Examples include alkoxy titanium.More specifically, for example, s i obtained by hydrolyzing alkoxy silane in the presence of an acid catalyst.
Compounds having an -o-3i bond, etc. can be preferably used.

One type of such metal alkoxide hydrolyzate may be used, or a plurality of types may be used in combination.

Furthermore, the metal alkoxide hydrolyzate may be prepared in advance by hydrolyzing the metal alkoxide before mixing with the inorganic filler or organic filler, or the metal alkoxide may be mixed with the inorganic filler or organic filler. It may be mixed with an organic filler and hydrolyzed in the mixture.

Conditions for hydrolysis, such as temperature, time, solvent, and whether or not to use a catalyst, can be determined as appropriate depending on the type and amount of metal alkoxide used.

As the inorganic filler, one having high weather resistance and chemical resistance can be used as appropriate. For example, materials made of zircon, zirconia, silica, talc, titania, mica, glass, graphite, stainless steel, or other metals or alloys can be used. These inorganic fillers may be used alone or in combination. Further, the shape thereof can be any desired shape, such as powder, flake, or fiber.

By blending the above inorganic filler and organic filler, the storage stability of the coating material can be significantly improved.

As the organic filler in this case, those consisting of vinyl acetate/beoba copolymer, vinyl acetate/ethylene copolymer, fluororesin, vinylidene chloride/acrylonitrile copolymer, silicone resin, or polyethylene can be used. I have these! ! Concerning the quality filler, one type thereof may be used, or a plurality of types may be used in combination.

Further, the shape thereof can be arbitrary, such as powder, flake, or fiber. In particular, it is preferable to use a powder of vinyl acetate/beoba copolymer or vinyl acetate/ethylene copolymer.

The blending ratio of the above metal alkoxide hydrolyzate, inorganic filler, and organic filler is 1 to 15 wt%, more preferably 2 to 10 wt% of the organic filler based on the total amount thereof. If the organic filler exceeds 15 wt%, weather resistance, heat resistance, flame retardance, etc. will be significantly reduced. On the other hand, if the organic filler content is less than 1 wt%, the formulation tends to settle and become a hard cake, resulting in decreased storage stability. In addition, if thick coating is applied, cracks are likely to occur, reducing workability and making it impossible to widely apply the coating material to various molded products and 'f8''a'i'lJ.

Of course, there is no particular restriction on the method of using the coating material of the present invention, and the target base material and the thickness of the coating layer can be adjusted as appropriate depending on the composition of the coating material, its use, etc.

In order to improve water resistance, chemical resistance, and abrasion resistance, it is preferable to infiltrate an organoalkoxysilane compound or a mixture thereof after coating with the coating material of the present invention.

In this case, the organoalkoxysilane compound may be infiltrated alone, but it is preferable to infiltrate it as a mixture of the organoalkoxysilane compound and a metal alkoxide hydrolyzate solution.

This makes it possible to further improve the a-mechanical strength of the coating layer.

Hereinafter, this invention will be specifically explained based on examples.

Examples 1 to 4 (Comparative Examples 1 to 4) (Preparation of coating material and coating of cement moldings) Ethyl silicate Si (OC21(s) 4 was mixed with IN hydrochloric acid, ethanol and water, and at 20'C. SiO in solution
□Hydrolyzed until the concentration was 25%.

An inorganic filler and an organic filler were mixed into this hydrolyzate solution as shown in Table 1 to prepare a coating material of the present invention.

Next, using these coating materials, mortar specimens (7
0x70x20m) was coated.

In this case, the coating thickness was all 400 μm (two or more coats).

Furthermore, in Examples 3 and 4, after coating, ethyl silicate was hydrolyzed to form sio.

The coating layer was subjected to two infiltration treatments using a mixed solution of 70 wt % with a concentration of 50% or more and a 30 wt % ethanol solution of methyltriethoxysilane.

In addition, for comparison, Table 1 was prepared in the same manner as in Examples 1 to 4.
A coating material was prepared with the following formulation and coated on the surface of the mortar specimen.

(Evaluation) (i) Storage Stability 11 IJ of the coating materials prepared in Example 1.2 and Comparative Example 1.2 were placed in a polyethylene wide-mouth container, sealed and allowed to stand. After 13!1 hours, 2 After one week, after 43!1 hours, and after 12 weeks, the state of mixing was observed when stirring.

The results are shown in Table 2 below.

Table ◎ - Easily remixed by stirring O... Remixability due to the equivalent clock νA factor △... Remixed by stirring → impossible As shown in Table 2, examples of the present invention Even if the filler precipitates after being left to stand for a long time, it is easy to achieve a good mixing state by stirring, but in the comparative example that does not contain organic filler, even if the filler is left to stand for a long time, Stirring became partially impossible. It had poor storage stability.

(ii) Weather resistance The coatings of the mortar specimens produced in Examples 1 to 4 and Comparative Examples 1 and 3 were left standing in a test room at a temperature of 20°C and a humidity of 60% for 24 hours, and then tested according to JIS^1415 (Plastic The weather resistance was evaluated by testing according to the Accelerated Exposure Test Method for Building Materials. In this case, the test conditions were an irradiation time of 2000 hours using a sunshine weather meter, and a spray cycle of 180 minutes for 12 minutes.

The evaluation method was as follows.

Appearance observation: presence or absence of cracks and yellowing by visual inspection; color difference =
-JIS z 813G (color difference display method) 6.3L
Color difference by ab (ΔE) Adhesion strength before and after irradiation: Average value of three adhesion strength tests (kg/d) The results are shown in Table 3 below.

Table 3 ◎ - No change Δ... Some changes As shown in Table 3, the examples of the present invention exhibit excellent characteristics in terms of external [111 observation, color difference, and adhesion strength]. On the other hand, cracks occur when no organic filler is blended (Comparative Examples 1 and 3). It was also confirmed that when an excessive amount of organic filler is blended, not only cracks but also yellowing occur, color difference is large, adhesion strength is reduced, and weather resistance is poor.

(iii) Heat resistance The coverings of the mortar specimens produced in Examples 1 to 4 were left standing in a test room at a temperature of 20°C and a humidity of 60% for 7 days, then placed in an electric furnace and heated at 300°C for 30 minutes. The appearance was observed visually and by touch.

As a result, although almost no change was observed, it was confirmed that when an excessive amount of organic filler was added, the color changed to brown, the coating layer was destroyed, and the heat resistance decreased.

(1v) Abrasion resistance The coatings of the mortar specimens produced in Example 2, Example 4, Comparative Example 1, and Comparative Example 3 were coated at a temperature of 20°C and a humidity of 60%.
JIS A 5209
(Ceramic tiles) Perform a drop type abrasion test according to
Abrasion loss was measured.

For comparison, abrasion loss was also measured in the same manner for glazed tiles (Comparative Example 5), epoxy resin paint coatings (Comparative Example 6), and composite RS, M fat emulsion paint coatings (Comparative Example 7).

The results are shown in Table 4.

Table 4 As shown in Table 4, the ## abrasion resistance of the examples of the present invention is superior to that of the comparative examples, and in particular, <Example 4) after the penetration treatment was applied to the glazed tiles (comparative examples) It was confirmed that the wear resistance was comparable to that of 5).

(ν) Chemical resistance Regarding the coatings of the mortar specimens of Examples 1 to 4 and Comparative Examples 1 to 4, the epoxy resin paint coating (Comparative Example 6), and the synthetic resin emulsion paint coating (Comparative Example 7), 5 %H
, So, , 5% HCI, Ca (OH) 2 saturated aqueous solution, 5% NaO'H, and toluene.

The results are shown in Table 5.

Table ◎ - No change after immersion for 28 days or more G: No change after immersion for 7 days or more Δ: Change after immersion within 3 days ×: Damaged when immersed within 24 hours Shown in Table 5 As can be seen, all the examples of this invention exhibit excellent chemical resistance, especially those subjected to penetration treatment (
It was confirmed that Example 3.4) exhibited high chemical resistance.

(Effects of the Invention) As explained in detail above, according to the present invention, it is possible to obtain a coating material that has high storage stability and excellent weather resistance, heat resistance, abrasion resistance, and chemical resistance. Become. l! Construction'f
It becomes possible to apply coatings with good workability and excellent durability to a wide range of objects such as M'a objects and civil engineering structures, as well as various majestic carved objects and 4IIL structures.

Claims (5)

[Claims] (1) A coating material comprising a metal alkoxide hydrolyzate mixed with a mixture of an inorganic filler and an organic filler. (2) The coating material according to claim (1), wherein the inorganic filler is selected from zircon, zirconia, silica, talc, titania, mica, glass, graphite, and stainless steel. (3) The coating material according to claim (1), wherein the organic filler is selected from vinyl acetate/beoba copolymer, vinyl acetate/ethylene copolymer, fluororesin, vinylidene chloride/acrylonitrile copolymer, silicone resin, and polyethylene. . (4) A method for coating a molded article with the coating material according to claim (1). (5) After coating with the coating material according to claim (1),
A method of coating a molded article by impregnating it with an organoalkoxysilane compound or a mixture thereof.