Photocurable silicone composition, and method of making the same

• US 5,179,134 A
• Filed: 11/19/1990
• Issued: 01/12/1993
• Est. Priority Date: 11/19/1990
• Status: Expired due to Term

• Current Assignee: Loctite Corporation (Henkel AG & Co KGaA)
• Original Assignee: Loctite Corporation (Henkel AG & Co KGaA)
• Inventors: Cross, Robert P., Chu, Hsien-Kun, Crossan, David I.
• Primary Examiner(s): McCamish, Marion E.
• Assistant Examiner(s): BERMAN, SUSAN W
• Application Number:
  US07/615,200
• Time in Patent Office: 785 Days
• Field of Search: 522/99, 522/172, 522/37, 522/40, 522/44, 522/46, 528/31, 528/32, 528/26, 528/34
• US Class Current: 522/37
• CPC Class Codes: C08G 77/50 by carbon linkages C08G77/485 takes precedence
• CPC Class Codes: C08L 83/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C08L83/10 takes precedence
• CPC Class Codes: C09D 183/14 in which at least two but not all the silicon atoms are connected by linkages other than oxygen atoms C09D183/10 takes precedence
• CPC Class Codes: C09K 2003/1062 UV-curable materials
• CPC Class Codes: C09K 2200/0247 Silica
• CPC Class Codes: C09K 2200/0625 Polyacrylic esters or derivatives thereof
• CPC Class Codes: C09K 3/1018 Macromolecular compounds having one or more carbon-to-silicon linkages

Abstract

An acryloxy-functional capped silicone formed as a reaction product of:

(i) a silyl diacrylate compound of the formula: ##STR1## wherein: R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, and R₁₀ are independently selected from hydrogen, halo, and organo radicals; and

n is an integer having a value of from 1 to 4; and

(ii) a silicone having at least one functionality which is reactive with an acryloxy functionality of the silyl diacrylate compound to yield the acryloxy-functional capped silicone.

The capped silicone may suitably be formulated with an effective amount of a photoinitiator for curing of the acryloxy-functional capped silicone under photoinitiating curing conditions. The silicone functionality which is reactive with the acryloxy functionality of the silyl diacrylate compound may be --OH, or other labile hydrogen-containing substituent. Preferably, the silicone is a hydroxy-terminated linear polydiorganosiloxane. The compositions of the invention are usefully employed as sealants, conformal coatings, potting materials, and the like, and are readily curable with UV radiation.

Claims

1. An acryloxy-functional capped silicone, formed as a non-hydrolysis reaction product of:

(i) a silyl diacrylate compound of the formula;

##STR19## wherein;

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, and R₁₀ are independently selected from hydrogen, halo, and organo radicals; and

n is an integer having a value of from 1 to 4; and

(ii) a silicone having at least one functionality which is reactive with an acryloxy functionality of said silyl diacrylate compound to yield said acryloxy-functional capped silicone.

2. A composition according to claim 1, wherein R₁, R₂, R₃, R₄, R₅, R₈, R₉, and R₁₀ are independently selected from hydrogen, halo, and C₁ -C₈ alkyl radicals, and R₆ and R₇ are independently selected from hydrogen, halo, C₁ -C₈ alkyl, and phenyl radicals.

3. A composition according to claim 1, wherein n has a value of from 1 to 2.

4. A composition according to claim 1, wherein:

R₁, R₂, R₉, and R₁₀ are hydrogen;

R₃, R₄, R₅, and R₈ are independently selected from hydrogen and C₁ -C₈ alkyl;

R₆ and R₇ are independently selected from C₁ -C₈ alkyl, and phenyl; and

n is 1.

5. A composition according to claim 1, wherein:

R₁, R₂, R₄, R₅, R₉, and R₁₀ are hydrogen;

R₃ and R₈ are independently selected from hydrogen and methyl;

R₆ and R₇ are methyl; and

n is 1.

6. A composition according to claim 1, wherein said silicone functionality which is reactive with the acryloxy functionality of the silyl diacrylate compound, comprises a functional group including a labile hydrogen constituent.

7. A composition according to claim 1, wherein said silicone functionality which is reactive with the acryloxy functionality of the silyl diacrylate compound, is a functionality selected from the group consisting of:

--N(R'"'"')₂, wherein each of the R'"'"' substituents is independently selected from hydrogen and organo groups, with the proviso that at least one R'"'"' substituent is hydrogen;

--SH;

--SO₃ H; and

##STR20## wherein each of the R'"'"' and R'"'"'" substituents is independently selected from hydrogen and organo groups;

with the proviso that said silicone functionality is ##STR21## only when the silyl diacrylate compound is present with residual acrylic acid groups deriving from the synthesis of the silyl diacrylate compound.

8. A composition according to claim 1, wherein the silicone having at least one functionality reactive with an acryloxy functionality of said silyl diacrylate compound, comprises a linear polydiorganosiloxane.

9. A composition according to claim 8, wherein said at least one reactive functionality of said silicone comprises a terminal reactive functional group.

10. A composition according to claim 1, wherein said silicone having at least one functionality reactive with an acryloxy functionality of said silyl diacrylate compound, comprises a linear silicone with hydroxy functional groups at its termini.

11. A composition according to claim 10, wherein said linear silicone has a weight average molecular weight of from about 700 to about 300,000.

12. A composition according to claim 1, wherein the reaction by which the reaction product is formed, is characterized by an equivalents ratio of acryloxysilyl functionality to acryloxy-reactive functionality of from about 1.0 to about 1.2.

13. A composition comprising a capped silicone according to claim 1, and an effective amount of a photoinitiator for curing of said capped silicone under photoinitiating curing conditions.

14. A composition according to claim 13, wherein the photoinitiator comprises a compound selected from the group consisting of benzophenone, benzoin, acetophenone, benzil, and their substituted forms, and mixtures thereof.

15. A composition according to claim 13, wherein the photoinitiator comprises diethoxyacetophenone.

16. A composition according to claim 13, further comprising a stabilizer.

17. A composition according to claim 13, further comprising a filler.

18. A composition according to claim 1, wherein said silyl diacrylate has the formula:

##STR22## wherein;

R is H or methyl; and

said silicone comprises a linear polydimethylsiloxane with terminal --OH groups at both ends.

19. A photocured silicone material produced by photocuring a composition comprising an acryloxy-functional capped silicone according to claim 1, under conditions photocuringly effective therefor.

20. A method of capping (i) a silicone having functionality which is reactive with acryloxy functionality, with (ii) acryloxy functionality to render the silicone photocurable in character, comprising non-hydrolyzingly reacting said silicone with a silyl diacrylate compound of the formula:

##STR23## wherein;

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, and R₁₀ are independently selected from hydrogen, halo, and organo radicals, and

n is an integer of from 1 to 4.

21. A method according to claim 20, wherein n has a value of 1.

22. A method of making a silicone composition which is photocurable under photocurable conditions optionally including the presence of a suitable photoinitiator therefor, comprising:

(a) reacting (i) an acrylic acid component of the formula;

##STR24## wherein;

R₁₃, R₁₄, and R₁₅ are independently selected from hydrogen, halo, and organo radicals;

with (ii) a chlorosilane compound of the formula;

##STR25## wherein;

R₄, R₅, R₆ and R₇ are independently selected from hydrogen, halo, and organo radicals; and

n is an integer of from 1 to 4;

to yield a silyl diacrylate compound of the formula;

##STR26## wherein;

R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉ and R₁₀ are independently selected from hydrogen, halo, and organo radicals; and

n is an integer of from 1 to 4; and

(b) non-hydrolyzingly reacting the silyl diacrylate compound with a silicone having at least one functionality which is reactive with an acryloxy functionality of the silyl diacrylate compound, to yield an acryloxy-functional capped silicone as the silicone composition.

23. A method according to claim 22, wherein R₁, R₂, R₃, R₄, R₅, R₈, R₉, and R₁₀ are independently selected from hydrogen, halo, and C₁ -C₈ alkyl radicals, and R₆ and R₇ are independently selected from hydrogen, halo, C₁ -C₈ alkyl, and phenyl radicals.

24. A method according to claim 22, wherein:

R₁, R₂, R₉, and R₁₀ are hydrogen;

R₃, R₄, R₅, and R₈ are independently selected from hydrogen and C₁ -C₈ alkyl;

R₆ and R₇ are independently selected from C₁ -C₈ alkyl and phenyl; and

n is 1.

25. A method according to claim 22, wherein:

R₁, R₂, R₄, R₅, R₉, and R₁₀ are hydrogen;

R₃ and R₈ are independently selected from hydrogen and methyl;

R₆ and R₇ methyl; and

n is 1.

26. A method according to claim 22, wherein said silicone functionality which is reactive with the acryloxy functionality of the silyl diacrylate compound, comprises a functional group including a labile hydrogen constituent.

27. A method according to claim 22, wherein said silicone functionality which is reactive with the acryloxy functionality of the silyl diacrylate compound, comprises a functionality selected from the group consisting of:

--OH;

--N(R'"'"')₂, wherein each of the R'"'"' substituents is independently selected from hydrogen and organo groups, with the proviso that at least one R'"'"' substituent is hydrogen;

--SH;

--SO₃ H; and

##STR27## wherein each of the R" and R'"'"'" substituents is independently selected from hydrogen and organo groups;

with the proviso that said silicone functionality is ##STR28## only when the silyl diacrylate compound is present with residual acrylic acid groups deriving from the synthesis of the silyl diacrylate compound.

28. A method according to claim 22, wherein said silicone having at least one functionality which is reactive with an acryloxy functionality of the silyl diacrylate compound, comprises a linear polydiorganosiloxane.

29. A method according to claim 28, wherein said at least one reactive functionality of said silicone comprises a terminal reactive functional group.

30. A method according to claim 22, wherein said silicone having at least one functionality which is reactive with an acryloxy functionality of the silyl diacrylate compound, comprises a linear silicone with hydroxy functional groups at its termini.

31. A method according to claim 30, wherein said linear silicone has a weight average molecular weight of from about 700 to about 300,000.

32. A method according to claim 22, comprising providing from about 1.0 to about 1.2 equivalents of acryloxysilyl functionality for reaction with the acryloxy-reactive functionality of said silicone.

33. A method according to claim 22, wherein said silyl diacrylate has the formula:

##STR29## wherein;

R is H or methyl; and

said silicone comprises a linear polydimethylsiloxane with terminal --OH groups at both ends.

34. A method according to claim 22, further comprising forming a photocurable silicone composition by mixing said acryloxy-functional capped silicone with a photoinitiator.

35. A method according to claim 34, wherein the photoinitiator is selected from the group consisting of benzophenone, benzoin, acetophenone, benzil, and substituted forms thereof, and mixtures thereof.

36. A method according to claim 34, wherein the photoinitiator comprises diethoxyacetophenone.

37. A method according to claim 34, further comprising exposing said photocurable silicone composition to radiation photocuringly effective therefor, to yield a photocured silicone composition.

38. A method according to claim 37, wherein said radiation comprises ultraviolet radiation.