Abstract: An improved process for the preparation of high viscosity (i.e., greater than 1 million mPa·s at 25° C.) silanol-terminated silicone polymers and copolymers, often referred to in the industry as silanol-terminated silicone polymer gums. The silanol-terminated silicone polymer gums are made by the ring-opening polymerisation of organocyclosiloxane oligomers (alternatively referred to as cyclic siloxane oligomers) using a conical screw dump extruder (1). It also relates to silanol-terminated silicone polymer gums made by the process.

Abstract: An improved process for the preparation of high viscosity (i.e., greater than 1 million mPa.s at 25° C.) silanol-terminated silicone polymers and copolymers, often referred to in the industry as silanol-terminated silicone polymer gums. The silanol-terminated silicone polymer gums are made by the ring-opening polymerisation of organocyclosiloxane oligomers (alternatively referred to as cyclic siloxane oligomers) using a conical screw dump extruder (1). It also relates to silanol-terminated silicone polymer gums made by the process.

Abstract: A continuous process for producing a silicone polymer comprises the sequential steps of (i) polymerisation of a linear silanol group containing siloxane by condensation polymerisation, or of a cyclosiloxane by ring opening polymerisation, or of a mixture of said linear and cyclosiloxanes with a phosphazene base in the presence of water and the presence or absence of a filler in an extruder, (ii) neutralising the reaction mixture in an extruder, and (iii) stripping the neutralised reaction mixture to remove volatile materials. Preferably, step (iii) is performed in an extruder, more preferably steps (i), (ii) and (iii) are all performed in the same extruder.

Abstract: A continuous process for producing a silicone polymer comprises the sequential steps of (i) polymerisation of a linear silanol group containing siloxane by condensation polymerisation, or of a cyclosiloxane by ring opening polymerisation, or of a mixture of said linear and cyclosiloxanes with a phosphazene base in the presence of water and the presence or absence of a filler in a static mixer, (ii) neutralising the reaction mixture in a static mixer, an in-line mixer or an extruder, and (iii) stripping the neutralised reaction mixture to remove volatile materials. Preferably step (ii) is performed in a static mixer and step (iii) is performed in a thin film stripper, extruder or co-rotating processor.

Abstract: A process for producing a silicone polymer having a volatile material content of less than 1% by weight, preferably less than 0.1% by weight, comprises the sequential steps of (i) producing an unstripped silicone polymer by polymerisation of a linear silanol group containing siloxane by condensation polymerisation, or of a cyclosiloxane by ring-opening polymerisation, or of a mixture of said linear and cyclosiloxanes, with a phosphazene base in the presence of water and the presence or absence of a filler, (ii) neutralising the catalyst, and (iii) stripping the unstripped silicone polymer, preferably at temperatures of 200.degree. C. and above.