Ladder-like silicone polymers

• US 20030212228A1
• Filed: 10/09/2002
• Published: 11/13/2003
• Est. Priority Date: 05/02/2002
• Status: Active Grant

• Current Assignee: DSO National Laboratories
• Original Assignee: DSO National Laboratories
• Inventors: Dai, Jie, Deng, Chaoran
• Granted Patent: US 7,022,799 B2
• Time in Patent Office: Days
• US Class Current: 528/10
• CPC Class Codes: C08G 77/04 Polysiloxanes
• CPC Class Codes: C08G 77/06 Preparatory processes C08G77/045 takes precedence
• CPC Class Codes: C08G 77/38 Polysiloxanes modified by chemical after-treatment C08G77/045 takes precedence

Abstract

There is disclosed a three stage method for the preparation of ladder-like silicone polymers. The first stage comprises hydrolysis and polymerization of alkyltrialkoxylsilane-like monomers to give relatively low molecular weight prepolymers. The second stage comprises dehydrated condensation polymerization of the prepolymers to give high molecular weight polymers. The third stage comprises partial blocking of a proportion of the pendant Si—OH (silanol) groups with a pre-determined sub-stoichiometric amount of a blocking agent. Also disclosed are the prepolymers, polymers and partially blocked polymers so produced.

Claims

1. A method for producing a polymer comprising the steps of:

(i) reacting an organic solution of at least one monomer having the formula;

R¹—

Si(OR²)(OR³)(OR⁴)

wherein R¹, R², R³ and R⁴ are each independently selected from the group consisting of;

hydrogen, alkyl, alkoxy, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl or heterocyclyl;

with a solution of an acid dissolved in water having a specific resistance of at least 18.2 MΩ

-cm, at a temperature below about 25°

C., to give a prepolymer, and

(ii) reacting a solution of the prepolymer with a solution of an alkaline catalyst at a temperature above about 25°

C. to give a polymer, and

(iii) reacting a proportion of the free Si—

OH groups of the polymer with a predetermined sub-stoichiometric amount of a blocking agent to give a partially blocked polymer.

2. A method according to claim 1 wherein R¹ is methyl, ethyl, propyl, butyl, n-hexyl, cyclohexyl, cyanopropyl, vinyl, hydro, aminopropyl, phenyl, or 3-glycidoxy propyl.

3. A method according to claim 1 wherein R², R³ and R⁴ are independently methyl or ethyl.

4. A method according to claim 1 wherein two different monomers are reacted together in step (i).

5. A method according to claim 1 wherein the concentration of the at least one monomer in step (i) is from about 0.5 to about 4 mol/kg solvent.

6. A method according to claim 5 wherein the concentration of the at least one monomer in step (i) is from about 1 to about 3 mol/kg solvent.

7. A method according to claim 6 wherein the concentration of the at least one monomer in step (i) is from about 2 to about 3 mol/kg solvent.

21. A method according to claim 1 wherein the acid in step (i) is selected from the group consisting of hydrochloric acid, phosphoric acid, sulphuric acid, acetic acid, and aromatic sulphonic acid.

22. A method according to claim 1 wherein the concentration of the prepolymer in step (ii) is from about 1 to about 30 wt %.

23. A method according to claim 22 wherein the concentration of the prepolymer in step (ii) is from about 5 to about 20 wt %.

24. A method according to claim 22 wherein the concentration of the prepolymer in step (ii) is about 10 wt %.

25. A method according to claim 1 wherein the reaction time for step (ii) is from about 0.5 to about 10 hours.

26. A method according to claim 25 wherein the reaction time for step (ii) is about 2 hours.

27. A method according to claim 1 wherein the solvent for step (ii) is methyl isobutyl ketone.

28. A method according to claim 1 wherein the reaction temperature for step (ii) is from about 30 to about 80°

C.

29. A method according to claim 28 wherein the reaction temperature for step (ii) is from about 40 to about 70°

C.

30. A method according to claim 1 wherein the catalyst for step (ii) is KOH in methanol.

31. A method according to claim 1 wherein the concentration of the catalyst solution used in step (ii) is about 1 g/l.

32. A method according to claim 1 wherein the concentration of the catalyst in the reaction mixture of step (ii) is from about 5 to about 20 wt % with respect to the prepolymer.

33. A method according to claim 32 wherein the concentration of the catalyst in the reaction mixture of step (ii) is from about 7 wt % with respect to the prepolymer.

34. A method according to claim 1 wherein the reaction time for step (iii) is from about 1 to about 5 hours.

35. A method according to claim 34 wherein the reaction time for step (iii) is from about 2 to about 4 hours.

36. A method according to claim 1 wherein the reaction time for step (iii) is from about 20 to about 90°

C.

37. A method according to claim 36 wherein the reaction time for step (iii) is from about 30 to about 80°

C.

38. A method according to claim 1 wherein the blocking agent for step (iii) is a trialkylchlorosilane.

39. A method according to claim 38 wherein the trialkychlorosilane is a dimethylalkylchlorosilane.

40. A method according to claim 39 wherein the alkyl group of the dimethyl alkyl chlorosilane is selected from the group consisting of methyl, 3-glycidoxypropyl, vinyl, hydro and cyanopropyl.

41. A method according to claim 1 wherein the blocking agent for step (iii) is hexamethyldisiloxane.

42. A method according to claim 1 wherein the amount of blocking agent used in step (iii) is from about 1 to about 90% per mole of Si-atoms in the polymer.

43. A method according to claim 42 wherein the amount of blocking agent used in step (iii) is from about 5 to about 50% per mole of Si-atoms in the polymer.

44. A method according to claim 43 wherein the amount of blocking agent used in step (iii) is from about 10 to about 30% per mole of Si-atoms in the polymer.

45. A method according to claim 44 wherein the amount of blocking agent used in step (iii) is from about 25%.

46. A method for producing a prepolymer as defined in claim 1.

47. A method for producing a polymer according to claim 1.

48. A method for producing a partially blocked polymer as defined in claim 1.

50. A prepolymer obtainable by claim 46.

51. A polymer obtainable by claim 47.

52. A partially blocked polymer obtainable by claim 48.

8. A method for producing a polymer comprising the steps of:

(i) reacting an organic solution of at least one monomer, the solution comprising at least one solvent selected from the group consisting of benzene, toluene, xylene, methyl isobutyl ketone, methyl ethyl ketone, diethyl ether and isopropyl ether, the at least one monomer having the formula;

R¹—

Si(OR²)(OR³)(OR⁴)

wherein R¹, R², R³ and R⁴ are each independently selected from the group consisting of;

hydrogen, alkyl, alkoxy, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl or heterocyclyl;

with a solution of an acid dissolved in water having a specific resistance of at least 18.2 MΩ

-cm, at a temperature below about 25°

C., to give a prepolymer, and

(ii) reacting a solution of the prepolymer with a solution of an alkaline catalyst at a temperature above about 25°

C. to give a polymer, and

(iii) reacting a proportion of the free Si—

OH groups of the polymer with a predetermined sub-stoichiometric amount of a blocking agent to give a partially blocked polymer.

9. A method according to claim 8 wherein the solution of the at least one monomer comprises methyl isobutyl ketone.

10. A method according to claim 8 wherein the reaction time for step (i) is from about 3 to about 48 hours.

11. A method according to claim 10 wherein the reaction time for step (i) is from about 8 to about 24 hours.

12. A method according to claim 11 wherein the reaction time for step (i) is from about 10 to about 20 hours.

13. A method according to claim 8 wherein the reaction temperature for step (i) is below about 15°

C.

14. A method according to claim 9 wherein the reaction temperature for step (i) is below about 5°

C.

15. A method for producing a polymer comprising the steps of:

(i) reacting an organic solution of at least one monomer having the formula;

R¹—

Si(OR²)(OR³)(OR⁴)

wherein R¹, R², R³ and R⁴ are each independently selected from the group consisting of;

hydrogen, alkyl, alkoxy, alkenyl, alkynyl, aryl, cycloalkyl, heteroaryl or heterocyclyl;

with a solution of an acid dissolved in water having a specific resistance of at least 18.2 MΩ

-cm, at a temperature below about 25°

C., to give a prepolymer, the molar ratio of the water to the at least one monomer being from about 3 to 1 to about 20 to 1.

and

(ii) reacting a solution of the prepolymer with a solution of an alkaline catalyst at a temperature above about 25°

C. to give a polymer, and

(iii) reacting a proportion of the free Si—

OH groups of the polymer with a predetermined sub-stoichiometric amount of a blocking agent to give a partially blocked polymer.

16. A method according to claim 15 wherein the molar ratio of the water to the at least one monomer is from about 6 to 1 to about 12 to 1.

17. A method according to claim 16 wherein the molar ratio of the water to the at least one monomer is from about 10 to 1 to about 12 to 1.

18. A method according to claim 15 wherein the concentration of the acid in step (i) is from about 1 to about 15 mol %.

19. A method according to claim 18 wherein the concentration of the acid in step (i) is from about 1 to about 5 mol %.

20. A method according to claim 19 wherein the concentration of the acid in step (i) is from about 2 to about 3 mol %.

49. A method for producing a partially blocked polymer comprising the step of reacting a proportion of the free Si-OH groups of a polymer with a predetermined sub-stoichiometric amount of a blocking agent to give a partially blocked polymer.