Curable silicone compositions incorporating a fluorescent detection system
View Patent ↗The present invention relates to curable silicone compositions which include a fluorescent agent for detection purposes and which have a cure system which enables the silicone compositions to possess improved depth of cure. The silicone compositions are photocurable, and may also be moisture or heat curable.
1. A curable silicone composition comprising:
(a) a photo-curable silicone resin having the following structure:
wherein MA is a methacryloxyalkyl group, R 1 and R 2 may be the same or different and are monovalent hydrocarbyl groups having up to 10 carbon atoms, or halo- or cyano-substituted hydrocarbyl groups, and n is from 1 to 1,200;
(b) an acylphosphine oxide photoinitiator; and
(c) a fluorescent dye in amounts of about 0.002% to 0.006% by weight of the total composition.
2. The composition of claim 1 , wherein the photoinitiator is a solid photoinitiator.
3. The composition of claim 1 , wherein the photoinitiator is dissolved in a solvent.
4. The composition of claim 1 , wherein the photoinitiator is dissolved in a non-polar solvent.
5. The composition of claim 1 , wherein the photoinitiator is selected from the group consisting of bisacylphosphine oxide, acylphosphine oxide and combinations thereof.
6. The composition of claim 1 , further including a moisture-cure catalyst.
7. The curable silicone composition of claim 1 wherein the composition further comprises a non-polar solvent for the photoinitiator.
8. The composition of claim 7 , wherein the non-polar solvent is selected from the group consisting of a silane, a liquid photoinitiator and combinations thereof.
9. The composition of claim 7 , wherein the photoinitiator is selected from the group consisting of bisacylphosphine oxide, acylphosphine oxide and combinations thereof.
10. The composition of claim 7 , further including a moisture-cure catalyst.
11. The composition of claim 1 , wherein the silicone resin comprises a free radical curing group selected from the group consisting of methacryloxy, vinyl and combinations thereof.
12. The composition of claim 1 , wherein the silicone resin comprises a moisture-curing group selected from the group consisting of alkoxy, acetoxy, enoloxy, methacryloxy, acryloxy, oxime, vinyl, amino, N,N-dialkylamino, N,N-dialkylaminoxy, N-alkylamido, and combinations thereof.
13. A method of detecting the presence of a silicone composition comprising:
providing a silicone composition according to claim 1 ;
shining a light of appropriate wavelength to permit absorption by the fluorescent dye; and
observing the subsequent fluorescent emission as an indication of the presence of the silicone composition.
14. A method for using the composition of claim 1 to join and/or seal together two substrates, comprising the steps of:
(a) applying the composition to at least one of two substrate surfaces;
(b) mating the substrate surfaces in an abutting relationship to form an assembly;
(c) exposing the composition to conditions of cure; and
(d) maintaining the abutting relationship for a time sufficient to allow the composition to cure.
15. A curable silicone composition comprising:
(a) a curable silicone resin;
(b) a cure system comprising a premix of an acylphosphine oxide photoinitiator dissolved in a liquid photoinitiator; and
(c) a fluorescent dye in amounts of about 0.002% to 0.006% by weight of the total composition.
16. The composition of claim 15 , wherein the acylphosphine oxide photoinitiator is initiated by UV and/or visible light.
17. A curable silicone composition comprising:
(a) a photo-curable silicone polymer;
(b) a fluorescent dye in amounts of about 0.002% to 0.006% by weight of the total composition;
(c) a premix comprising a first photoinitiator comprising a member selected from the group consisting of a bisacylphosphine oxide, acylphosphine oxide and combinations thereof;
a second photoinitiator different from the first; and
at least one non-polar solvent.
18. A dual photo/moisture curing silicone composition having enhanced cure-through-depth comprising:
(a) a photo-moisture curable silicone component having the following structure:
wherein MA is a methacryloxyalkyl group, R 1 and R 2 may be the same or different and are monovalent hydrocarbyl groups having up to 10 carbon atoms, or halo- or cyano-substituted hydrocarbyl groups, and n is from 1 to 1,200;
(b) a premix of an acylphosphine oxide photoinitiator in a solvent carrier; and
(c) a fluorescent dye in amounts of about 0.002% to 0.006% by weight of the total composition.
19. A method of preparing a photo-curable silicone composition comprising:
(a) providing a photo-curable silicone resin having the following structure:
wherein MA is a methacryloxyalkyl group, R 1 and R 2 may be the same or different and are monovalent hydrocarbyl groups having up to 10 carbon atoms, or halo- or cyano-substituted hydrocarbyl groups, and n is from 1 to 1,200;
and
(b) mixing the curable silicone polymer with an acylphosphine oxide photoinitiator and a fluorescent dye,
wherein the fluorescent dye is present in amounts of about 0.002% to 0.006% by weight of the total composition.
20. A composition comprising the reaction product of:
(a) a photo-curable silicone resin having the following structure:
wherein MA is a methacryloxyalkyl group, R 1 and R 2 may be the same or different and are monovalent hydrocarbyl groups having up to 10 carbon atoms, or halo- or cyano-substituted hydrocarbyl groups, and n is from 1 to 1,200;
(b) a premix of a solid acylphosphine oxide photoinitiator and a solvent for said solid photoinitiator; and
(c) a fluorescent dye in amounts of about 0.002% to 0.006% by weight of the total composition.