Composite silicone membranes of high separation efficiency

A composite membrane, comprising:

• a separating membrane layer and a support membrane,
• wherein the separating membrane layer comprises a cured mixture of silicone acrylates, the mixture comprising:
• from 70 to 90% by weight of a component (A);
• and
• from 10 to 30% by weight of a component (B);
• wherein
• component (A) is at least one silicone acrylate of Formula I, having a silicon content of on average greater than 29% by weight,
• wherein,
• a is from 25 to 500,
• b is 0,
• c is from 0 to 20, and
• each R2=R3, and
• component (B) is at least one silicone acrylate of Formula I, having a silicon content of less than 27.5% by weight, wherein,
• a is from 1 to 24,
• b is from 3 to 25,
• c is from 0 to 20, and
• each R2 is R1 or R4,
• each R1 is independently an alkyl or aryl radical having from 1 to 30 carbon atoms, optionally comprising an ether group, an ester group, an epoxy group, an alcohol group, or a combination thereof,
• each R3 is independently an organic radical comprising one or more acrylate groups, and
• each R4 is independently a polyether radical.