Organopolysiloxane compositions crosslinkable into elastomeric silicone foams

An organopolysiloxane composition crosslinkable into a silicone foam having a density of less than 0.20 g/cm3, and a tensile strength of greater than 0.10 MPa;

• said composition consisting essentially of:
• (A) at least one polyorganosiloxane (A) having, per molecule, at least two C2-C6 alkenyl radicals bonded to silicon and having a viscosity ranging from 10 to 300,000 mPa·s and said polyorganosiloxane (A) comprises end vinylsiloxy units,
• (B) at least one polyorganosiloxane (B) having, per molecule, at least two hydrogen atoms bonded to silicon and having a viscosity ranging from 1 to 5,000 mPa·s,
• (C) a catalytically effective amount of at least one platinum group metal catalyst (C),
• (D) at least one compound (D) selected from the group consisting of n-propanol, n-butanol, n-hexanol and n-octanol,
• (E) optionally, at least one diorganopolysiloxane oil (E) blocked at each end of its chain by a triorganosiloxy structural unit, the organic radicals of which bonded to silicon atoms are selected from among alkyl radicals having from 1 to 8 carbon atoms, 3,3,3-trifluoropropyl radicals, cycloalkyl radicals, and aryl radicals,
• (F) optionally, at least one inorganic and/or metal filler (F),
• (G) optionally, at least one additive (G), and
• (H) at least one polyorganosiloxane resin (H), with the provisio that:
• (1) said resin (H) is present in a proportion of at least 10% by weight, with respect to the total weight of the polyorganosiloxane (A) and of the polyorganosiloxane resin (H) (=ratio by weight (H)/[(A)+(H)]×100);
• and
• (2) said resin (H) comprises at least two different siloxyl structural units selected from among those of the following formulae (I) and (II):
• WaZbSiO(4−(a+b))/2 (I)
• in which:
• the W symbols, which may be identical or different, are each a C2-C6 alkenyl radical;
• the Z symbols, which may be identical or different, are each a nonhydrolyzable monovalent, optionally halogenated hydrocarbon radical that does not adversely affect the activity of the catalyst;
• a is 1 or 2, b is 0, 1 or 2 and the sum a+b is equal to 1, 2 or 3, and
• ZcSiO(4−c)/2 (II)
• in which Z is as defined above and c is equal to 0, 1, 2 or 3, and
• at least one of the structural units (I) or (II) is a T or Q unit, and
• with the further proviso that the viscosity of said composition is less than 15,000 mPa s,
• said composition being devoid of:
• (i) water, as porogenic agent generating, in the presence of a polysiloxane comprising hydride functional groups, gaseous hydrogen,
• (ii) polyorganosiloxane comprising hydroxyl groups, and
• (iii) cyclic polydiorganosiloxane comprising ≡SiH functional groups.