JPH0288480A - Treatment for preventing discoloration of clay roofing tile - Google Patents

Abstract

PURPOSE:To prevent the discoloration of a clay roofing tile on ageing over a long period by treating a fired clay roofing tile with an organosilicic compd. CONSTITUTION:The surface of a fired clay roofing tile is treated with a mate rial selected from a group of (A) the alkali metal salt of the phenyltrialkoxysilane shown by the formula or its condensate, (B) the alkali metal salts of at least two kinds of the condensate of the alkyltrialkoxysilane shown by R<a>Si(OR<b>)3 and having a different R<a>, and (C) the alkali metal salt of the condensate of R<a>Si(OR<b>)3 and R2<c>Si(OR<b>)2 (R<a> is a 1-2 C alkyl or phenyl, and R<b> is a 1-4 C alkyl).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a surface treatment method for preventing discoloration of fired clay tiles, which are widely used as roof tiles, etc., and particularly for preventing discoloration over a long period of time. This paper relates to a discoloration prevention treatment method for clay roof tiles.

[Conventional technology]

As fired clay tiles used as roof tiles etc. are exposed to the outside air for a longer period of time, black spots appear on the surface or discoloration occurs, such as fading, resulting in the building's exterior looking outdated.

In order to prevent this discoloration, conventional methods have been known to coat the surface of clay tiles with a synthetic resin film such as polyvinyl chloride or transparent paint to prevent contact with the outside air. It is being

[Problem that the invention seeks to solve]

However, in the above method, the weather resistance of the synthetic resin is limited, and the film and paint deteriorate due to direct sunlight, and the film and paint peel off from the tile surface due to temperature changes between day and night.

Furthermore, in the case of oxidized roof tiles, the surface is coated with synthetic fiber resin, so the bright silver color that is inherent in oxidized roof tiles is not expressed, resulting in a plastic-like appearance.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for preventing discoloration of clay roof tiles, which prevents discoloration over a long period of time and improves the drawbacks of the above-mentioned known techniques.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is characterized in that a fired clay roof tile is subjected to surface treatment using a substance selected from the following groups: (al, mountain) and (cl).

+al Alkali metal salt R'(clR'5l(OH2)3 and >3 i (OR '
)t(D alkali metal salt of condensate) where R1 is an 01-C3 alkyl group or a phenyl group, and R- is a C1-C4 alkyl group.

General formula % formula % of the above +al is phenyltrimethoxysilane, and the alkali metal salts of this are, for example, sodium phenylsiliconate and potassium phenylsiliconate for phenyltrimethoxysilane, and the alkali metal salt of this condensate is sodium phenylsiliconate. These are water-soluble compounds such as phenyl polysiliconate and potassium phenyl polysiliconate.

The general formula R''S i (OR'h of the aforementioned (bl) is a methyl, ethyl or phenyl trialkoxysilane, the alkoxy group is a methoxy, ethoxy, propoxy or butoxy group, and the alkali metal salt of this condensate is For example, sodium methylethyl polysiliconate is used for methyltrialkoxysilane and ethyltrialkoxysilane, sodium methylphenylpolysiliconate is used for methyltrialkoxysilane and phenyltrialkoxysilane, and sodium methylphenyl polysiliconate is used for methyltrialkoxysilane and phenyltrialkoxysilane. In this case, sodium ethyl phenyl polysiliconate is used, and both are water-soluble compounds.

Furthermore, among the aforementioned (e), dialkoxysilanes having the general formula % nyl, methylethyl, methylphenyl or ethylphenyl, the alkoxy group being a methoxy, ethoxy, propoxy or butoxy group, and these compounds, For example, in the case of methyltrialkoxysilane and diphenyldialkoxysilane, the alkali metal salt of the condensate with the compound shown in (bl) is sodium methyldiphenyl polysiliconate, which is a water-soluble compound.

These substances i +a+, (bl and (C1) can be used alone or in combination in any ratio, and when used, a fired clay tile is added to a solution of these substances. For example, the surface is treated by dipping for 30 seconds.

[Effect]

The above-mentioned substances (al, (bl, and (C1) are all applied to the surface of fired clay tiles to block contact between the atmosphere and the surface of the clay tiles and prevent discoloration of the clay tiles for a long period of time. .

〔Example〕

Uraship ■ - 1 mol of each starting material shown in Sample Nl 1-11 of Table 1 above was collected in a 50011 J three-necked flask,
18 g of 0.25% hydrochloric acid was added dropwise to these, and after refluxing for 1 hour, the mixture was heated to a temperature of 180° C. and cooled to obtain a condensate.

Next, each of these condensates Log was dissolved in 10 g of 25% sodium hydroxide, and water was added to make 2000 g to obtain a sodium metal salt. Table 1 shows each sample obtained.
Shown as medium magnets 1-11.

Three fired clay tiles were placed in the solution of each of these samples.
Apply each sample solution to the surface of the clay tile by dipping it for 0 seconds, then leave it outside to observe the discoloration of the surface and report the results.
Shown in 1. For reference, an untreated clay tile without any surface treatment was also used as a blank and the surface discoloration was observed in the same manner, and the results are shown in Table 1.

In Table 1, ◎ means no discoloration at all, ○ means almost no discoloration,
Δ indicates slight discoloration, and × indicates discoloration.

From Table 1, it can be seen that samples Arashi 1 to 11 did not discolor despite being exposed outdoors for a long period of time, whereas the blank sample was severely discolored.

1 ship ±-1 Collect 10g of phenyltrimethoxysilane and add 2
Dissolve 10 g of 5% sodium hydroxide and add water to make 20
00 g of sodium metal salt was obtained. A clay tile was immersed in this sample solution in the same manner as in Example 1, the sample solution was applied to the surface of the clay tile, and then the clay tile was left outdoors to observe the state of discoloration on the surface. As a result, almost no discoloration was observed even after 24 months.

〔Effect of the invention〕

As described above, the present invention prevents discoloration of clay tiles for a long period of time by applying the above-mentioned (al, -) or (C1 substance) to the surface of fired clay tiles, thereby improving the appearance of buildings for a long period of time. It is a practically useful invention that can be kept fresh for many years.

Claims (1)

[Scope of Claims] A discoloration prevention treatment method for clay tiles, which comprises surface-treating fired clay tiles using a substance selected from the following group (a), (b) and (c). (a) Alkali metal salts of the general formula ▲ Numerical formulas, chemical formulas, tables, etc. are available, either alone or as a condensate. (b) At least two types of R^aSi(OR^b)_3 in which R^a is different. Alkali metal salt of condensate (c) R^aSi(OR^b)_3 and ▲mathematical formula, chemical formula,
There are tables etc. Alkali metal salt of condensate of ▼ However, R^a is an alkyl group of C_1 to C_2 or a phenyl group, and R^b is an alkyl group of C_1 to C_4.