| 摘要 |
PROBLEM TO BE SOLVED: To provide a defoaming agent which can be diluted in a wide range of the concentration by producing a water-in-oil type emulsion by adding polyorgano siloxane having a specified formula, fine powder silica having a specified average particle size, an emulsifying agent having a specified hydrophilicity-hydrophobicity ratio, a specified thickener, and water. SOLUTION: A defoaming agent concentrate forming a water-in-oil type emulsion is produced by adding about 1-99wt.% of polyorgano siloxane having a formula MDx M, about 0.01-50.0wt.% of fine powder silica having about 0.001-1000μm average particle size, about 0.10-50.0wt.% of an emulsifying agent having about 2-20 hydrophilicity-lipophilicity ratio, about 0.001-20.0wt.% of a thickener with molecular weight about 100-100,000,000 Dalton, and slightly more than 0wt.% and not more than 20.0wt.% of water. In the formula MDx M, M=R<1> R<2> R<3> SiO1/2 , D=R<4> R<5> SiO2/2 wherein R<1> -R<5> stand for univalent hydrocarbon groups and x for about 1-10000.
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