Dual cure compositions
This disclosure relates to polysiloxanes and polysiloxane compositions having dual-curable properties, to methods for forming articles from such compositions, and to articles formed thereby. In one embodiment, the polysiloxane comprises at least about two alkenyl groups and at least about two (meth)acryloyl groups.
1. A polysiloxane having at least about two vinyl or allyl groups and at least about two (meth)acryloyl groups per molecule, the polysiloxane having the structural formula:
A-B P —C q —B X -D Y -B Z -A′
wherein
A is
and A′ is
in which each of R 1 , R 2 , R 3 , R 10 , R 11 , and R 12 is independently vinyl, allyl, [((meth)acryloyloxy) C 1 -C 12 alkyl], or C 1 -C 6 hydrocarbon;
B is
in which each of R 4 and R 5 is independently C 1 -C 6 hydrocarbon;
C is
in which R 6 is vinyl or allyl and R 7 is C 1 -C 6 hydrocarbon;
D is
in which R 8 is [((meth)acryloyloxy) C 1 -C 12 alkyl] and R 9 is C 1 -C 6 hydrocarbon; and
each of P, q, X, Y, and Z is independently 0-20,000, provided that at least one of P, Q, X, Y, and Z is not zero, and that the first polysiloxane comprises at least two alkenyl groups and at least two (meth)acryloyl groups.
2. The polysiloxane of claim 1 , wherein each vinyl or allyl group is a vinyl group.
3. The polysiloxane of claim 1 , comprising a number of vinyl or allyl groups within the range of 2 to 1,000.
4. The polysiloxane of claim 1 , wherein the number of siloxane repeat units of the polysiloxane comprising an alkenyl group is within the range of 0.001% to 20% of the total number of siloxane repeat units of the polysiloxane.
5. The polysiloxane of claim 1 , wherein the at least about two vinyl or allyl groups are provided as pendant groups from internal siloxanes of the polysiloxane.
6. The polysiloxane of claim 1 , wherein the at least about two vinyl or allyl groups are provided at ends of the polysiloxane.
7. The polysiloxane of claim 1 , wherein each (meth)acryloyl group is a (meth)acryloyloxyalkyl group.
8. The polysiloxane of claim 1 , comprising about 2 (meth)acryloyl groups.
9. The polysiloxane of claim 1 , comprising a number of (meth)acryloyl groups in the range of 3 to 1,000.
10. The polysiloxane of claim 1 , wherein the number of siloxane repeat units of the polysiloxane comprising a (meth)acryloyl group is within the range of 0.001% to 20% of the total number of siloxane repeat units of the polysiloxane.
11. The polysiloxane of claim 1 , having a viscosity within the range of 2,000 cst to 15,000 cst.
12. The polysiloxane of claim 1 , having the structural formula
wherein each R is independently C 1 -C 3 alkyl, each Q is independently vinyl, allyl, or C 1 -C 3 alkyl, each T is H or CH 3 , b is in the range of 1.9 to 5, and a and c are selected to provide the polysiloxane with an overall mole percentage of (meth)acrylate-bearing siloxane subunits in the range of 1-20% on a silicon mol % basis, and a, b and c are selected to provide a weight-average molecular weight of no more than 1000000 Da.
13. The polysiloxane of claim 1 , having structural formula
wherein each R is independently C 1 -C 3 alkyl, each T is H or CH 3 , b is in the range of 1.9 to 5, and a and b are selected to provide a weight-average molecular weight of no more than 1000000 Da.
14. A polymerizable composition comprising
a first polysiloxane according to claim 1 , present in an amount within the range of 2 wt. % to 99.9 wt. %;
an effective amount of a photoinitiator; and
an effective amount of a thermal initiator.
15. The composition of claim 14 , further comprising one or more of
a third polysiloxane having at least about one alkenyl group, present in an amount within the range of 0.05 wt. % to 60 wt. %; and
a fourth polysiloxane having at least about one (meth)acryloyl group, present in an amount within the range of 0.05 wt. % to 40 wt. %.
16. A method for preparing a three-dimensional body, the method comprising
providing a polymerizable composition according to claim 14 ; and
irradiating at least a portion of the polymerizable composition with actinic radiation effective to initiate reaction of the photoinitatior; and
thermally post-curing the irradiated composition.
17. The method of claim 16 , wherein the irradiation is performed such that a portion of the polymerizable is not irradiated, the method further comprising, before thermally post-curing the irradiated composition, separating the irradiated composition from the non-irradiated polymerizable composition.
18. An article made by a method of claim 17 .
19. An article that is the polymerization product of a polymerizable composition of claim 14 .
20. A polymerizable composition comprising:
a first polysiloxane according to claim 1 , present in an amount within the range of 2 wt. % to 99.9 wt. %;
a second polysiloxane having at least about two Si—H groups, present in an amount within the range of 0.05 wt. % to 50 wt %;
an effective amount of a photoinitiator; and
an effective amount of a hydrosilylation catalyst.
21. A method for preparing a three-dimensional body, the method comprising providing a polymerizable composition according to claim 20 ; and
irradiating at least a portion of the polymerizable composition with actinic radiation effective to initiate reaction of the photoinitatior; and
thermally post-curing the irradiated composition.
22. The method of claim 21 , wherein the irradiation is performed such that a portion of the polymerizable is not irradiated, the method further comprising, before thermally post-curing the irradiated composition, separating the irradiated composition from the non-irradiated polymerizable composition.