Polyorganosiloxane release coating and method for its preparation and use

A method for making a release liner comprising:

• 1) applying to a substrate, a release coating composition comprising:
• A) a combination of branched polyorganosiloxanes, where the combination comprises
• I) 50 to 90 weight parts of a branched siloxane of unit formula (A-I) (R13SiO1/2)a(R2R12SiO1/2)b(R12SiO2/2)c(SiO4/2)d, where each R1 is independently a monovalent hydrocarbon group free of aliphatic unsaturation and each R2 is an aliphatically unsaturated hydrocarbon group, where subscript a≥0, subscript b>0, subscript c is 15 to 995, and subscript d is >0;
• II) 10 to 50 parts by weight of a silsesquioxane of unit formula (A-III) (R13SiO1/2)e(R2R12SiO1/2)f(R12SiO2/2)g(R1SiO3/2)h, where subscript e≥0, subscript f>0, subscript g is 15 to 995, and subscripth>0;
• where amount of the branched siloxane and amount of the silsesquioxane combined total 100 weight parts;
• B) a crosslinker having at least 3 silicon bonded hydrogen atoms per molecule in an amount sufficient to provide a molar ratio of silicon bonded hydrogen atoms to aliphatically unsaturated groups (SiH:Vi ratio) in the release coating composition of >1:1 to 5:1, based on the weight of the release coating composition;
• C) an amount of a platinum group metal catalyst sufficient to provide 1 to 1,000 ppm by weight of a platinum group metal, per 100 parts by weight of starting material A);
• and
• D) 0.001 to 1 parts by weight, per 100 parts by weight of starting material A);
• of an inhibitor, thereby forming a mixture,
• optionally E) a polydiorganosiloxane having an average of one or more terminally aliphatically unsaturated groups per molecule;
• optionally F) an anchorage additive;
• and
• optionally G) a solvent, thereby forming a release coating composition;
• and
• optionally 2) treating the substrate before applying the release coating composition, and
• 3) heating the release coating composition, thereby curing the release coating composition to form a cured release coating on the substrate.