Process for preparing branched Si-H functional polysiloxanes and use thereof for preparing liquid SiC- or SiOC-linked, branched modified organomodified polysiloxanes
AssigneeEvonik Goldschmidt GmbH
InventorsFrauke Henning, Wilfried Knott, Michael Ferenz
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Abstract
The invention provides a process for preparing liquid, branched SiH-functional siloxanes by reacting a mixture of one or more low molecular weight SiH-functional siloxanes, one or more low molecular weight SiH-free siloxanes, one or more tetraalkoxysilanes, and optionally one or more trialkoxysilanes with addition of water and in the presence of a Brønsted-acidic ion exchanger, which is characterized in that the reaction is performed in one process step.
Claims9
A process for preparing a branched SiH-functional siloxane liquid at a temperature of 25° C. and a pressure of 101 325 Pa, said process comprising reacting in a single step a mixture that comprises:
- a) one or more SiH-functional siloxanes,
- b) one or more SiH function-free siloxanes,
- c) one or more tetraalkoxysilanes,
- in the presence of water and at least one solid, Brønsted-acidic catalyst selected from an acidic ion exchanger, wherein the water is added in the form of a mixture which comprises one or more organic solvents miscible with water in a weight ratio of 1 to 1 without phase separation.
Dependencies are inferred from the claim text.