Patent ID: 6511754
Filing Date: 2003-01-28
Classification: B60R,C08K,C09D,D06N,Y10T

Abstract:
Process for preparing a coating composition of the type which are cold-curing (RTV), and the composition itself comprising:(1) at least one polyorganosiloxane having, per molecule, at least two C2-C6 alkenyl groups linked to the silicon, (2) at least one polyorganosiloxane having, per molecule, at least two hydrogen atoms linked to the silicon, (3) a catalytically effective amount of at least one catalyst, composed of at least one metal belonging to the platinum group, (4) a ternary adhesion promoter comprising (4.1) at least one alkoxylated organosilane containing, per molecule, at least one C3-C6 alkenyl group, (4.2) at least one organosilicon compound which includes at least one epoxy radical, (4.3) at least one metal M chelate and/or one metal alkoxide of general formula: M(OJ)n, with n=the valency of M and J=a linear or branched C1-C8 alkyl, M being selected from the group consisting of: Ti, Zr, Ge, Li, Mn, Fe, Al and Mg, (5) a reinforcing siliceous filler treated in situ by a compatibilizer in the presence of polyorganosiloxane (1), (6) a polyorganosiloxane termed an extender and having terminal siloxyl units with hydrogeno functional groups, (7) optionally a neutralizer, (8) optionally a crosslinking inhibitor and/or one or more other additives used in this type of composition, (9) and optionally expanded or expandable inorganic hollow microspherical fillers, said in situ treatment of the filler comprising the steps of introducing the compatibilizer in two stages into a preparation mixture containing reinforcing siliceous filler and polyorganosiloxane (1):(stage 1) on the one hand, before or simultaneously with the contacting of at least some of the polyorganosiloxane employed with at least one portion of the siliceous filler used, this introduction of compatibilizer taking place in one or more increments and corresponding to a proportion of less than or equal to 8% by dry weight with respect to the total filler; and (stage 2) on the other hand, adding the remaining portion of compatibilizer after the above polyorganosiloxane contacting.