BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates generally to photocurable compositions and methods for continuously forming a three-dimensional body from these compositions. More particularly, the present disclosure relates to photocurable compositions comprising a mixture of polysiloxanes capable of being dually cured, i.e., by UV radiation followed by thermal treatment, or by UV radiation only.

2. Technical Background

The manufacturing of polymeric three-dimensional (3-D) bodies based on a layer-by-layer buildup of a radiation curable liquid material has become of increasing interest, especially in view of the enhancement in production speed when a bottom-up technique is employed.

Curable compositions including polysiloxanes can be subjected to a curing process to form a reaction product of the polysiloxane, e.g., a cured material. This cured material is often in the form of a cross-linked material, where a liquid curable composition is rendered into a gel or solid by forming bonds between different polysiloxane chains. Cross-linked polysiloxanes can have variety of desirable properties. However, curable polysiloxane compositions have been generally unsuitable for printing or manufacturing of polymeric three-dimensional bodies, due to at least one of insufficient shear-thinning properties, insufficient transparency of the cured product, inconveniently slow curing time, difficulty of controlling dimensions of cured material, difficulty of processing due to high viscosity and unsuitability for efficient and effective use with various printing techniques.

Accordingly, there remains a need for photocurable compositions suitable for three-dimensional fabrication of polymeric articles.

SUMMARY OF THE DISCLOSURE

In one aspect, the present disclosure provides a photocurable composition, comprising:a first polysiloxane comprising at least two acrylate or methacrylate groups per molecule;a second polysiloxane containing at least one Si—H group per molecule;a third polysiloxane containing at least one reactive aliphatic ethylene group per molecule;a free radical photoinitiator in an amount of about 0.01 to about 10 weight % based on the total weight of (meth)acrylate-containing polysiloxane in the composition; anda hydrosilylation catalyst in an amount of about 0.001 to about 10 weight % based on the total weight of hydride-containing polysiloxane and vinyl-containing polysiloxane in the composition.

Another aspect provides methods of forming a three-dimensional body comprising: providing a photocurable composition of the disclosure; and curing the photocurable composition, e.g., with actinic radiation, to form a cured (e.g., photocured) three-dimensional body.

Another aspect provides methods of forming a three-dimensional body comprising: providing a photocurable composition of the disclosure; curing the photocurable composition with actinic radiation to form a photocured three-dimensional body; and curing the photocured three-dimensional body with heat to form a heat-cured three-dimensional body.

