Photo-radical cure of silicones

Abstract

Silicone-based elastomeric materials, articles containing the silicone-based elastomeric materials, reaction mixtures used to form the silicone-based elastomeric materials, and methods of making the silicone-based elastomeric materials are described. The silicone-based elastomeric materials are prepared by polymerizing silicone compounds having at least two ethylenically unsaturated groups in thepresence of actinic radiation and a controlled radical initiator. The controlled radical initiators are bis-dithiocarbamate or bis-dithiocarbonate compounds having a single carbon between the two dithiocarbamate or dithiocarbonate groups. The silicone-based elastomeric materials typically have improved mechanical properties compared to silicone-based elastomeric materials formed by free radical polymerization reactions in the presence of conventional photoinitiators.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of U.S. Provisional Patent Application 62 / 564,518, filed September 28, 2017, the disclosure of which is incorporated herein by reference in its entirety. Background technique [0003] Silicone-based elastomeric materials have been prepared by curing silicones with terminal ethylenically unsaturated groups with actinic radiation in the presence of conventional photoinitiators for free-radical reactions (e.g., Norrish Type 1 photoinitiators). . Advantageously, the curing method can occur in the absence of organic solvents and / or in the presence of heat sensitive materials such as heat sensitive substrates. However, one disadvantage of this curing method is that the resulting silicone-based elastomeric materials often have poor mechanical properties. [0004] Living-controlled free-radical polymerization methods have been developed that allow the preparation of polymers with well-defin...

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Problems solved by technology

However, one disadvantage of this curing method is that the resulting silicone-based elastomeric materials often have poor mechanical properties

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