Dow Silicones Corporation

James Andrew Kenney

Bizhong Zhu

Timothy J Gallagher

Phillip Griffith

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 (). It also relates to silanol-terminated silicone polymer gums made by the process.

Polymerisation of siloxane polymers

A method of forming a three-dimensional (3D) article comprises the steps of I) printing a first photocurable silicone composition with a 3D printer to form a layer, II) irradiating the layer with an energy source to form an at least partially cured layer, III) printing a second photocurable silicone composition on the at least partially cured layer with the 3D printer to form a subsequent layer, and IV) irradiating the subsequent layer with the energy source to form an at least partially cured subsequent layer. Optionally, steps III) and IV) can be repeated with independently selected photocurable silicone compositions for any additional layer(s) to form the 3D article. The first and second photocurable silicone compositions are the same as or different from one another. Various pho-tocurable silicone compositions can be utilized for the inventive method, including the inventive photocurable silicone compositions described herein.

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Midland, MI, United States of America

James Andrew Kenney