Resin-reinforced UV, moisture and UV/moisture dual curable silicone compositions

• US 6,828,355 B1
• Filed: 01/18/2002
• Issued: 12/07/2004
• Est. Priority Date: 07/19/1999
• Status: Expired due to Term

• Current Assignee: Henkel IP & Holding GmbH (Henkel AG & Co KGaA)
• Original Assignee: Henkel Corporation (Henkel AG & Co KGaA)
• Inventors: Chu, Hsien-Kun
• Primary Examiner(s): Seidleck, James J.
• Assistant Examiner(s): MCCLENDON, SANZA L
• Application Number:
  US10/031,361
• Time in Patent Office: 1,054 Days
• Field of Search: 522/60, 522/24, 522/66, 522/71, 522/81, 522/104, 522/105, 522/99, 522/172, 522/148, 525/280, 525/281, 525/282, 525/410, 525/411, 525/437, 525/445
• US Class Current: 522/99
• CPC Class Codes: C08G 77/14 containing silicon bound to oxygen-containing groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/18 to alkoxy or aryloxy groups
• CPC Class Codes: C08G 77/20 containing silicon bound to unsaturated aliphatic groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/70 Siloxanes defined by use of the MDTQ nomenclature
• CPC Class Codes: C08K 5/0025 Crosslinking or vulcanising agents; including accelerators
• CPC Class Codes: C08L 2666/28 Non-macromolecular organic substances
• CPC Class Codes: C08L 83/00 Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 83/04 Polysiloxanes
• CPC Class Codes: C08L 83/06 containing silicon bound to oxygen-containing groups C08L83/12 takes precedence
• CPC Class Codes: C09D 183/06 containing silicon bound to oxygen-containing groups C09D183/12 takes precedence
• CPC Class Codes: C09J 183/04 Polysiloxanes

Abstract

This invention relates to resin-reinforced silicone compositions curable upon exposure to radiation in the electromagnetic spectrum, which compositions when cured demonstrate improved elastomeric properties, such as tensile strength, modulus and elongation. The inventive resin-reinforced silicone compositions may alternatively be rendered curable by exposure to moisture. In addition, the inventive composition may be rendered curable by exposure to radiation in the electromagnetic spectrum, and exposure to moisture. The inventive silicone compositions are particularly well suited for use in electronic conformal coating and potting applications, as well as in automotive gasketing applications, pressure sensitive adhesive applications and the like.

Claims

1. A resin-reinforced silicone composition curable by exposure to radiation in the electromagnetic spectrum, exposure to moisture and combinations thereof, comprising:

(a) a polyorganosiloxane with reactive groups selected from the group consisting of photocurable groups, moisture curable groups, and combinations thereof;

(b) a silicone resin selected from

(i) those formed from at least one silane within the formula R¹_mR²_pSi(X)<sub>4−

(m+p)</sub> I, where R¹ is a (meth)acrylate functional group or a hydrolyzable group, and R² may be the same or different and may be selected from the group consisting of monovalent ethylenically unsaturated radicals, hydrogen, C_1-12 alkyl, C_6-12 aryl, C_7-18 alkylaryl, and hydrolyzable groups, X is a hydrolyzable group, m is an integer from 1 to 3, and m+p is an integer from 1 to 3;

(ii) those formed from at least one silane within the formula R³_qSi(X)<sub>4−

q</sub> II, where R³ may be the same as or different from R² above and may be selected from monovalent ethylenically unsaturated radicals, hydrogen, C_1-12 alkyl, C_6-12 aryl, C_7-18 alkylaryl, and q is an integer from 1 to 3, reacted with at least another silane within the formula of R⁴_rR⁵_sSi(X)<sub>4−

(r+s)</sub> III, where R⁴ and R⁵ may be the same or different and may be selected from monovalent ethylenically unsaturated radicals, hydrogen, C_1-12 alkyl, C_6-12 aryl, C_7-18 alkylaryl, r is an integer from 1 to 3, and r+s is an integer from 1 to 3, provided the silicone resin formed contains at least some hydrolyzable group, X; and

combinations thereof; and

(c) a cure catalyst selected from the group consisting of a photoinitiator component;

a moisture curing catalyst, and combination thereof.

2. The composition of claim 1, wherein the silicone resin is formed as a reaction product of the at least one silane within the formula R¹_mR²_pSi(X)₄₋

(m+p) I, and at least one other silane within the formula, R_nSi(X)<sub>4−

n</sub> IV, wherein R may be the same or different and selected from the group consisting of hydrogen, C_1-2 alkyl, C_6-12 aryl, C_7-18 arylalkyl, C_7-18 alkylaryl, haloalkyl, and haloaryl, X is a hydrolyzable functionality, and n is an integer from 0 to 3.

3. The composition of claim 1, wherein the photocurable group is selected from the group consisting of acrylate, methacrylate and glycidoxyl groups.

4. The composition of claim 3, wherein the acrylate group is acryloxypropyl and the methacrylate group is methacryloxypropyl.

5. The composition of claim 1, wherein the polyorganosiloxane is within the formula:

wherein R⁶, R⁷, R⁸ and R⁹ may be the same or different and are alkyl, alkenyl, aryl, and (meth)acryl, provided that at least one of R⁶, R⁷, R⁸ or R⁹ is (meth)acryl, having up to 10 carbon atoms (C_1-10), or substituted versions thereof;

R¹⁰ is alkyl having up to 10 carbon atoms;

n is an integer between about 150 and 1,200;

a is 1 or 2;

b is 0, 1 or 2; and

a+b is 1, 2 or 3.

6. The composition of claim 1, wherein the moisture curable group is an alkoxy group.

7. The composition of claim 1, wherein the photoinitiator component is selected from the group consisting of substituted or unsubstituted benzoin, benzophenone, dialkoxybenzophenones, Michler'"'"'s ketone, diethoxyacetophenone and combinations thereof.

8. The composition of claim 6, wherein the photoinitiator component is diethoxyacetophenone.

9. The composition of claim 1, wherein the moisture curing catalyst is selected from the group consisting of organic titanium derivatives, organic tin derivatives and combinations thereof.

10. The composition of claim 1, wherein the photocurable group is reactive when exposed to elevated temperature conditions.

11. The composition of claim 1, further comprising a reactive diluent component.

12. The composition of claim 11, wherein the reactive diluent is a member selected from the group consisting of vinyl-terminated polydimethlylsiloxane, vinylterminated silicone resin, and combinations thereof.

13. The composition of claim 2, wherein the at least one first silane is present in an amount within the range of from about 1 to about 10 mole % and the at least one other silane is present in an amount within the range of from about 90 to about 99 mole %, of the total of the silanes.

14. The composition of claim 1, wherein the polyorganosiloxane is present in an amount within the range of from about 15 to about 85 mole % of the total composition.

15. The composition of claim 1, wherein the photoinitiator component is present in an amount within the range of from about 0.1 to about 5 mole % of the total composition.

16. The composition of claim 1, wherein the moisture curing catalyst is present in an amount within the range of from about 0.1 to about 5 mole % of the total composition.

17. Irradiated reaction products of the composition of claims 1.

18. Moisture cure reaction products of the composition of claim 1.

19. The reaction products of claim 17, further cured by moisture.

20. The reaction products of claim 17, further cured by heat.

21. A method of curing a silicone composition to form an elastomer, the steps of which comprise:

a. applying a silicone composition of claim 1 to a substrate; and

b. irradiating the substrate with UV irradiation sufficient to substantially cure the composition.

22. A method of curing a silicone composition to form an elastomer, the steps of which comprise:

a. applying a silicone composition of claim 1 to a substrate; and

b. exposing the composition to moisture sufficient to substantially cure the composition.

23. A method of curing a UV/moisture dual curing silicone composition to form an elastomer, the steps of which comprise:

a. applying a silicone composition of claim 1 to a substrate having shadow areas not readily accessible to ultraviolet or visible radiation in an amount sufficient to coat the ultraviolet and visible radiation-accessible and the shadow areas;

b. irradiating the substrate with UV irradiation sufficient to substantially cure the composition in the ultraviolet and visible radiation-accessible area; and

c. exposing the composition on the substrate to moisture for a time sufficient to cure the composition in the shadow areas.

24. The reaction products of claim 18, further cured by heat.

25. The reaction product of claim 19, further cured by heat.