USE OF TOCOPHEROL

• US 20100036079A1
• Filed: 03/11/2008
• Published: 02/11/2010
• Est. Priority Date: 03/12/2007
• Status: Active Grant

• Current Assignee: Bayer Schering Pharma OY (Bayer AG)
• Original Assignee: Bayer Schering Pharma OY (Bayer AG)
• Inventors: Jukarainen, Harri, Tiitinen, Emilia
• Granted Patent: US 8,044,161 B2
• Time in Patent Office: Days
• US Class Current: 528/15
• CPC Class Codes: C08G 77/08 characterised by the catalysts used
• CPC Class Codes: C08G 77/14 containing silicon bound to oxygen-containing groups C08G77/045 takes precedence
• CPC Class Codes: C08G 77/38 Polysiloxanes modified by chemical after-treatment C08G77/045 takes precedence

Abstract

The present invention relates to the use of tocopherol as a co-catalyst in the ring opening polymerisation of cyclic siloxanes. The present invention further relates to a method for manufacturing hydrophilic polysiloxanes, wherein a hydrido-containing cyclic siloxane is reacted with a hydrophilic molecule comprising a carbon-carbon double bond, having the general formula (I) H₂C═CH—(CHR)_n—O—(CHR¹CR²R³)_mR⁴ or (II) H₂C═CH—(CHR)_n—R⁵, wherein n is an integer from 0 to 4, m is an integer from 0 to 5, R, R¹, R², R³ and R⁴ are each independently hydrogen or a C₁ to C₆ alkyl, R⁵ is a saturated cyclic hydrocarbon containing carbonyl group, in the presence of a first catalyst to obtain a monomer, and polymerising said monomer in the presence of a second catalyst and tocopherol as a co-catalyst.

Claims

1. Use of tocopherol as a co-catalyst in the ring opening polymerisation of cyclic siloxanes.

2. Use according to claim 1, characterised in that said tocopherol is selected from the group consisting of D′

L-α

-tocopherol, RRR-α

-tocopherol, D′

L-α

-tocopherol acetate and RRR-α

-tocopherol acetate.

3. Use according to claim 1, characterised in that the cyclic siloxane is selected from the group consisting of heptamethyl cyclotetrasiloxane and tetramethyl cyclotetrasiloxane.

4. A method for manufacturing hydrophilic polysiloxane polymers, wherein a hydrido-containing cyclic siloxane is reacted with a hydrophilic molecule comprising a carbon-carbon double bond, having the general formula (I) or (II)

H₂C═

CH—

(CHR)_n—

O—

(CHR¹CR²R³)_mR⁴ 

 

(I)

H₂C═

CH—

(CHR)_n—

R⁵ 

 

(II)

wherein n is an integer from 0 to 4, m is an integer from 0 to 5, R, R¹, R², R³ and R⁴ are each independently hydrogen or a C₁ to C₆ alkyl, R⁵ is a saturated cyclic hydrocarbon containing carbonyl group, in the presence of a first catalyst to obtain a monomer, and polymerising said monomer in the presence of a second catalyst and tocopherol as a co-catalyst.

5. The method according to claim 4, characterised in that the cyclic siloxane is selected from the group consisting of heptamethyl cyclotetrasiloxane and tetramethyl cyclotetrasiloxane.

6. A hydrophilic polysiloxane obtainable by the method of claim 4.

7. A method for manufacturing a hydrophilic siloxane elastomer, comprising cross-linking a polysiloxane according to claim 6 in the presence of a cross-linking catalyst.

8. The method according to claim 7, characterised in that the cross-linking catalyst is selected from the group consisting of peroxide cross-linking catalyst and platinum cross-linking catalyst.

9. A hydrophilic siloxane elastomer obtainable by the method according to claim 7.

10. A hydrophilic siloxane elastomer according to claim 9, characterised in that it is platinum free.

11. A hydrophilic polysiloxane having the formula (III)

EB—

[B₁—

B₂—

B₃]_k-EB 

 

(III)

wherein

EB is an end blocker group, B₁, B₂ and B₃ is independently selected from the group consisting of a —

Si—

O—

chain comprising a hydrophilic group and a methyl group, a —

Si—

O—

chain comprising two methyl groups and a —

Si—

O—

chain comprising a vinyl group and a methyl group,

said B₁, B₂ and B₃ are randomly distributed along the chain of the polysiloxane, and k is an integer from 15 to 50 000, obtainable by the method according to claim 7.