Low viscosity compositions and 3D printing methods utilizing compositions

Abstract

The invention discloses a composition for forming a silicone elastomer. The composition comprises: A) a linear organopolysiloxane having at least two silicon-bonded ethylenically unsaturated groups per molecule; B) a linear organohydrogensiloxane having at least two silicon-bonded hydrogen atoms per molecule; C) at least one cross-linker; and D) a hydrosilylation catalyst. The cross-linker C) is selected from the group consisting of: C1) an organopolysiloxane having at least three silicon-bonded ethylenically unsaturated groups per molecule; and C2) an organopolysiloxane having at least threesilicon-bonded hydrogen atoms per molecule. At least one of the silicon-bonded ethylenically unsaturated groups of component C1) has a lower reactivity relative to the silicon-bonded ethylenically unsaturated groups of component A). Moreover, at least one of the silicon-bonded hydrogen atoms of component C2) has a lower reactivity relative to the silicon-bonded hydrogen atoms of component B). Theinvention discloses also methods of forming three-dimensional (3D) articles utilizing the compositions.

Description

[0001] Cross References to Related Applications [0002] This application claims priority and all advantages of U.S. Provisional Application 62 / 726,417, filed September 03, 2018, the contents of which are incorporated herein by reference. technical field [0003] This disclosure relates to compositions for forming silicone elastomers, and in particular, to low viscosity compositions comprising combinations of telechelic polymers of varying functionality, to silicone elastomers formed from such compositions, to the preparation of Such compositions and silicone elastomers, and methods involving 3D printing such compositions to form 3D elastomeric articles. The initial viscosity of the composition is low while still providing desirable cured elastomeric properties such as excellent elongation, modulus, ductility, and the like. Background technique [0004] When high elongation and toughness are required, silicone-based elastomeric systems are typically formulated with high mol...

AI Technical Summary

Problems solved by technology

These materials are not suitable for certain end applications based on physical or chemical limitations, cost, slow setting (or curing) time, unsuitable viscosity, etc.

[0007] Furthermore, in these types of printing methods, there are industry-wide problems between the printability of the composition and the mechanical properties of the final printed and cured article

For example, printability may require silicone compositions to have low viscosity and reasonable surface tension; however, silicone compositions with low viscosity typically have low molecular weight, and cured products from them have poor mechanical properties

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