Patent ID: 6521699
Filing Date: 2003-02-18
Classification: C08G,C08J,C08L

Abstract:
An aqueous silicone dispersion having a volatile organic compounds content of less than or equal to 0.5% by weight, which can be cross-linked, by condensation, to an adherent elastomer, comprising, condensable hydroxylated constituents free of hydrolysable organo functional substituents, capable of generating volatile organic compounds in situ during the hydrolysis or during the cross-linking by condensation;said dispersion comprising:Aâ€”at least one polydiorganosiloxane having, per molecule, at least two OH groups; Bâ€”at least one water-soluble adherence promoter being a silane or a polyorganosiloxane which is hydroxylated and carry, per molecule, at least one hydroxyl group and at least one hydrophilic function for anchoring onto a support, hereafter referred to as Fas, being identical to or different from each other and selected from the group consisting of amino, acrylo, methacrylo, ureido, mercapto, thiol, and chloroalkyl, the silane being monoFas-trihydroxy-monosilane, the polyorganosiloxane being obtained by one of the two following processes: process 1: a) co-hydrolysis of at least one silane S1 substituted with Fas groups and with at least a â€”OR group wherein R is an hydrocarbon group which are identical to or different, and of at least one silane S2 substituted with â€”OR groups which are identical to or different, excluding Fas substituents, to obtain hydrolysates, b) heterocondensation of the hydrolysates derived from the silanes S1 and S2, c) and then stripping or steam distillation of the hydrolysates derived from the â€”OR groups, process 2: aa) hydrolysis of a silane S3 substituted with Fas groups and â€”OR groups, to obtain hydrolysed S3 silanes and hydrolysates derived from the â€”OR groups, bb) homocondensation of the hydrolysed S3 silanes, cc) and by â€œstrippingâ€  vapour distillation of the hydrolysates derived from the â€”OR groups, the products of hydrolysis of alkoxylated epoxyfunctional silanes being excluded, Câ€”optionally, at least one organometallic condensation catalyst, Dâ€”optionally, at least one surfactant, Eâ€”and, optionally, at least one cross-linking agent with the proviso that: in the presence of the cross-linking agent (E), the promoter (B) only contains at least one OH group per molecule, and in the absence of the cross-linking agent (B), the promoter (B) or the POS (A) comprises at least three OH groups.