Patent ID: 8030371

Claim:
A method for preparing single-component alkoxy silicone sealant, comprising: a) preparing, in a stirred reactor, a masterbatch M that does not contain a curing catalyst H according to the steps a-1) and a-2) below: a-1) preparing a silicone composition comprising: i) at least one organopolysiloxane A having terminal and/or pendent alkoxylated groups; ii) at least one mineral filler B based on amorphous silica, optionally at least one other filler selected from the group consisting of crystalline silica, calcium carbonate, a filler having a lamellar structure and combinations thereof; iii) optionally at least one silane crosslinker C1 having alkoxylated functional groups; iv) optionally at least one nonreactive linear diorganopolysiloxane D of formula (I): in which: iv-1) the R 1 substituents, which are identical or different, each represent an aliphatic, cyclanic or aromatic, substituted or unsubstituted, saturated or unsaturated, C 1 to C 13 monovalent hydrocarbon-based radical; and iv-2) m has a value to give the polymer of formula (I) a dynamic viscosity at 25° C. ranging from 10 to 200 000 mPas; and v) optionally at least one auxiliary agent F selected from the group consisting of adhesion promoters F1, antifungal agents F2, bactericides F3, inert organic diluents F4, plasticizers F5, thixotroping agents F6, stabilizers F7 and combinations thereof; and a-2) said silicone composition resulting from step a-1) continues to be stirred and is subjected to a devolatilization operation in order to obtain said masterbatch M; b) preparing the single-component alkoxy silicone sealant by adding to said stirred masterbatch M: b-1) an effective amount of a curing catalyst G alone or in the form of a preparation comprising said curing catalyst G; b-2) optionally at least one auxiliary agent F selected from the group consisting of adhesion promoters F1, antifungal agents F2, bactericides F3, inert organic diluents F4, plasticizers F5, thixotroping agents F6, stabilizers F7 and combinations thereof; b-3) optionally a supplement of said mineral filler B; and b-4) optionally at least one colored pigment H alone or in the form of a preparation comprising said colored pigment H; and c) optionally a finishing step is carried out during which the single-component alkoxy silicone sealant continues to be stirred and is subjected to a devolatilization operation carried out under a pressure below atmospheric pressure, wherein the organopolysiloxane A having terminal and/or pendent alkoxylated groups is obtained in situ by functionalization: of at least one reactive organopolysiloxane I comprising at least two hydroxyl groups; in the presence of a catalytically effective amount of a functionalization catalyst J; and of at least one silane crosslinker C2 having alkoxylated functional groups, and the functionalization catalyst J comprises at least one component selected from the group consisting of: lithium hydroxide of formula LiOH or LiOH.H 2 O; sodium hydroxide; and potassium hydroxide.