The present disclosure relates to a method for preparing polyorganosiloxanes, comprising the following steps: a) reacting together a hydroxyl-terminated polysiloxane and a dialkoxysilane or an oligomer thereof in the presence of Catalyst 1, and b) reacting the product of Step a) with an endcapper in the presence of Catalyst 2 to form the polyorganosiloxane. According to this method, poly-organosiloxanes with an appropriate degree of the polymerization and viscosity are prepared by the polycondensation and equilibration reactions sequentially, and can significantly reduce the viscosity, and improve the flowability and thermal conductivity of the resulting silicone compositions, compared with other polysiloxanes at the same high thermally conductive filler loading.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of buffer mixtures and optionally an additional condensation catalyst and optionally in the presence of an inert solvent.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of buffer mixtures and optionally an additional condensation catalyst and optionally in the presence of an inert solvent.

Curable condensation compounds are useful, obtainable by the reaction of end-equilibrated acetoxy group-bearing siloxanes with at least one alkoxy-functional polysiloxane, in the presence of a catalyst.

Curable condensation compounds are useful, obtainable by the reaction of end-equilibrated acetoxy group-bearing siloxanes with at least one alkoxy-functional polysiloxane, in the presence of a catalyst.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Equilibrated trifluoromethanesulfonic acid-acidified α,ω-diacetoxypolydimethylsiloxanes, processes for the production thereof and SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA and a process for the production thereof are described, wherein the production of SiOC-bonded, linear polydimethylsiloxane-polyoxyalkylene block copolymers of the structure type ABA is effected by reacting trifluoromethanesulfonic acid-acidified acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Described is a process for producing SiOC-bonded polyether siloxanes branched in the siloxane portion from cyclic branched siloxanes of the D/T type, wherein said process comprises in a first step reacting the mixtures of cyclic branched siloxanes of the D/T type with acetic anhydride optionally in admixture with simple siloxane cycles under acid catalysis to afford acetoxy-bearing branched siloxanes, in a second step performing the equilibration of the acetoxy-modified branched siloxane with superacid, preferably with addition of acetic acid and in a third step reacting the superacid-treated acetoxysiloxane with polyetherols optionally in the presence of bases and optionally in the presence of an inert solvent.

Upcycling process for producing acidic, end-equilibrated siloxanes bearing acetoxy groups and having chain lengths of greater than 3 silicon atoms from end-of-life silicones by thermal digestion in an acidic reaction medium comprising acetic anhydride, acetic acid and at least one further Brønsted acid having a pKa of <4, the digestion taking place in a reactor having a volume of at least 1 liter.

A silicone rubber-based curable composition according to the present invention includes an organopolysiloxane including a vinyl group-containing organopolysiloxane (A), and an inorganic filler including silica particles (C), in which in a .sup.1H-NMR spectrum of the silicone rubber-based curable composition, a first peak derived from a vinyl group is present, a vinyl group index is equal to or less than 3.5×10.sup.−1% by mole, and a content of the inorganic filler satisfies a range of equal to or more than 5 parts by weight and equal to or less than 60 parts by weight with respect to 100 parts by weight of the organopolysiloxane.