Process and device for coating a support using a crosslinkable silicone composition

A process for the continuous coating of a traveling support strip of a textile material, the coating being a silicone elastomer composition comprising:

• i) at least one polyorganosiloxane A having ethylenically unsaturated reactive groups;
• ii) at least one crosslinking agent B;
• iii) an effective amount of a catalyst C;
• iv) at least one crosslinking inhibitor D;
• v) an adhesion promoter G, the adhesion promoter G comprising a) an alkoxylated organosilane G1 having, per molecule, at least one C2-C6 alkenyl group;
• b) an organosilane compound G2 comprising at least one epoxy radical;
• and c) a chelate G3 of a metal M and/or a metal alkoxide of the general formula M(OJ)n wherein n is the valency of M and J is a linear or branched C1-C8 alkyl and M is selected from the group consisting of Ti, Zr, Ge, Li, Mn, Fe, Al and Mg;
• vi) a constituent H that increases the mechanical strength of the coating, the constituent H being selected from from the group consisting of a) an unsaturated polyorganosiloxane resin H1;
• b) an inorganic reinforcing filler H2;
• and c) an organic or inorganic hollow microspherical filler H3;
• the process comprising:
• a) continuously preparing in a premixing means a premix comprising A, B, D, G1, G2 and H;
• b) continuously preparing in a mixing means a homogenous mixture of constituents A, B, C, D, G and H by mixing the premix with a mixture comprising C, G3 and optionally A, the homogeneous mixture being prepared under the following conditions:
• aa) a bath lifetime (BLT) at 30° C. of from 1 to 24 hours;
• bb) a differential scanning calorimetry DSC signature having at least one Gaussian peak showing:
• aaa) a peak start temperature T1:
• bbb) a peak summit temperature T2;
• and
• ccc) a peak end temperature T3;
• the Gaussian peak having the following:
• aaaa) T3 from 110° C. to 200° C.
• bbbb) ΔT=T3−T1 of from 20° C. to 100° C.;
• cccc) T1≦100° C.;
• and
• dddd) ΔT=ΔTref±10° C.
• wherein ΔTref=ΔT3,ref−ΔT1,ref is obtained from the DSC signature peak of a reference ABCDGH mixture, the homogeneous mixture being prepared at a flow rate corresponding to the rate of consumption of the homogenous mixture at a coating member and the constitution of a buffer reserve;
• c) conveying the homogenous mixture from the mixing means to the coating means;
• d) coating the traveling support strip with the homogenous mixture from the coating means;
• and
• e) allowing the crosslinking to occur.