| 摘要 |
PURPOSE:To obtain a condensation product free from terminal silanol group and capable of forming an excellent coating film, by hydrolyzing a tetraalkoxysilane with dialkyldialkoxysilane or their oligomers in the presence of an acid catalyst, and condensing the product at a specific pH. CONSTITUTION:The organic silicon compound of formula I (R is 1-8C hydrocarbon group) and/or its oligomer is mixed with the organic silicon compound of formula II (R' is 1-12C hydrocarbon group; R is same as that of formula I ) and/or its oligomer, and the mixture is hydrolyzed in the presence of an acid catalyst. The hydrolyzed product is condensed at >=7pH by adding an alkaline substance to the mixture. Concretely, the compound of formula I and the compound of formula II are added to a water-soluble solvent, mixed with 0.2-2mol of water (based on 1mol of RO bonded to Si) at <=6pH in the presence of formic acid, etc., made to react with each other at 20-100 deg.C for 30min-10hr, and adjusted to preferably 7.5-8.5pH with an alkaline substance to effect the condensation reaction.
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