JPH1160301A - Cement admixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cement admixture giving a cement product which does not cause efflorescence and has fine appearance by incorporating alkali salts of a fatty acid, a water-soluble solvent and water. SOLUTION: The cement admixture contains alkali salts of a fatty acid, a water-soluble solvent and water and has <=5,000 cP viscosity at 25 deg.C. The fatty acid is, e.g. lauric acid, palmitic acid, stearic acid, behenic acid or oleic acid but a mixture of such fatty acids is preferably used in consideration of profitableness. The alkali salts are potassium, sodium and ammonium salts and are contained in the admixture by >=20 wt.%. The water-soluble solvent is not especially limited if it well dissolves the alkali salts when mixed with water in a certain ratio. The solvent is, e.g. methanol, ethanol, isopropanol, Ethyl Cellosolve or ethylene glycol. A mixture of two or more solvents may be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement admixture used for the purpose of preventing bleaching of cement products. By using the product of the present invention, it is possible to produce a cement product having a beautiful appearance free from efflorescence.

[0002]

2. Description of the Related Art There is a phenomenon called efflorescence as an aesthetic problem of a cement product such as a color block or a joint material of a tile. Efflorescence is a phenomenon in which white precipitates are formed on the surface of cement hardening, and when this phenomenon occurs, particularly, the surface of a colored mortar or the like has a very unsightly appearance.

[0003] The true nature of this white flower is that Ca (OH) ₂ dissolved in water in cement is hardened by capillary action and conveyed to the surface, where water evaporates from the surface and simultaneously reacts with carbon dioxide in the air. It finally becomes CaCO ₃ and precipitates on the surface.

[0004] Research for preventing such whitening has been carried out for a long time, and generally, various waterproofing substances have been used as whitening inhibitors. For example, aluminum stearate powder, potassium stearate powder, sodium oleate powder and the like are known.

[0005]

SUMMARY OF THE INVENTION We have been producing and selling potassium and sodium stearate powders as anti-whitening agents for many years. However, it has been pointed out that the powder is difficult to measure automatically as a disadvantage, and the demand for liquefaction is increasing. However, although both potassium stearate and sodium oleate are slightly soluble in water or organic solvents, high-concentration liquids of about 40 to 50% cannot be obtained and thus have not been put to practical use. Thus, an object of the present invention is to make an alkali salt of a fatty acid into a fluid liquid.

[0006]

Means for Solving the Problems Alkaline salts of fatty acids generally hardly dissolve in water or various solvents. As a result of intensive studies, the inventors have found that an alkali salt of a fatty acid is well dissolved in a mixture of water and an organic solvent. For example, potassium stearate is only slightly soluble in water and ethyl alcohol alone, but 40 g is dissolved in a mixture of 36 g of water and 24 g of ethyl alcohol and has a viscosity of 25 cp (at 25 ° C.). To a clear liquid.

Examples of the fatty acids used in the present invention include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid and the like. These fatty acids may be used alone or in a mixture, but in general, a mixture is often used in consideration of economy.

[0008] The alkali salts used in the present invention include:
The potassium, sodium and ammonium salts of the above fatty acids.

Examples of the water-soluble solvent used in the present invention include, but are not limited to, methanol, ethanol, isopropanol, n-propanol, ethyl cellosolve, ethylene glycol and propylene glycol monomethyl ether. Instead, the point is,
What is necessary is just to dissolve the alkali salts of fatty acids well when mixed with water at a fixed ratio. These solvents may be used as a mixture of two or more kinds.

[0010]

The present invention will be described in more detail with reference to examples.

Example 1 Potassium stearate powder for industrial use (manufactured by Nippon Color Industrial Co., Ltd.)
40 g, ethyl alcohol 24 g and water 36 g were mixed well to obtain 100 g of a transparent liquid. The viscosity of this liquid is 25
It was 25 cp at ° C.

Example 2 40 g of industrial oleic acid powder (manufactured by Nippon Color Industry Co., Ltd.), 24 g of isopropyl alcohol and 36 g of water were mixed well to obtain 100 g of a transparent liquid. The viscosity of this liquid was 24 cp at 25 ° C.

Example 3 Industrial-use ammonium oleate (manufactured by Nippon Color Industrial Co., Ltd.) 3
0 g, propylene glycol monomethyl ether 35 g
And 35 g of water were mixed well to obtain 100 g of a transparent liquid.
The viscosity of this liquid was 28 cp at 25 ° C.

[0014]

According to JIS A1404 (Testing method for cement waterproofing agent for building) 9. Perform the test according to the water absorption test,
The presence or absence of efflorescence was observed. Test pieces prepared by adding 2% of the liquids obtained in Examples 1 to 3 to cement, respectively,
While a lot of efflorescence occurred on the test piece to which no test piece was added, almost no efflorescence was observed. Further, since the liquid of the present invention has a low viscosity, automatic measurement is easily performed.

Claims (3)

[Claims] 1. A cement admixture comprising an alkali salt of a fatty acid, a water-soluble solvent and water. 2. The cement admixture according to claim 1, wherein the content of the alkali salt of the fatty acid is 20% by weight or more. 3. The cement admixture according to claim 1, which has a viscosity of not more than 5,000 centipoise at 25 ° C.