Process for preparing organically modified siloxanes

1. A process for preparing siloxanes modified with organic esters, by hydrosilylating siloxanes with terminally unsaturated esters, which comprises preparing the terminally unsaturated esters used using at least one enzyme as catalyst.

2. The process as claimed in claim 1 , wherein terminally unsaturated esters used are compounds of the general formula I

where

W is hydrogen or methyl,

m is 0 to 28,

n is 0 or 1,

o is 0 to 100,

A is an oxyalkenyl radical of the general formula Ia

where

X radicals independently are identical or different radicals from the group —H, —CH 3 , —CH 2 CH 3 or -phenyl,

p is from 0 to 20,

B if p=1 is a glycerol-derived oxyalkenyl radical, optionally esterified with R b , of the general formula Ib

where

R b is the acyl radical of linear, branched, saturated or unsaturated carboxylic acids having 2 to 30 carbon atoms and optionally carrying additional hydroxyl groups, or

B if p=1 is the radical of the general formula Ic

where

Y and Z independently of one another are identical or different radicals from the group —H, —CH 3 , —CH 2 CH 3 , —CH 2 OH or —CH 2 OR b ,

where

R b is defined as above, or

B if p≧2 is a polyglycerol radical formed from monomers of glycerol and optionally esterified with R b ,

R b is defined as above,

R a is hydrogen, R a1 or R a2 ,

where

R a1 is a linear or branched, saturated or unsaturated alkyl radical having 1 to 200 carbon atoms which optionally carries hydroxyl groups, optionally carries hydroxyl groups esterified with carboxylic acids and optionally carries amino, alkylamino or dialkylamino groups,

R a2 is a radical of the general formula Id

and

R c is a saturated or unsaturated difunctional hydrocarbon radical having 2 to 20 carbon atoms,

where

q=0 or 1 provided that n+q=1, and

if R a is hydrogen, then q is 0 and o+p≧1.

3. The process as claimed in claim 2 , wherein esters of the general formula I are used

where

n, o and p are 0,

W is hydrogen,

m is 1 to 28,

q is 1,

R a , R a1 ═R a11 or R a ═R a2 ,

where

R a2 is defined as in claim 2 and

R a11 is the alkyl radical derived from commercially customary acids, such as acetic acid, propanoic acid, butanoic acid, pentanoic acid, chloroacetic acid, trifluoroacetic acid, ethylhexanoic acid, isononanoic acid, isotridecanoic acid or isostearic acid, or the alkyl radical derived from mono-basic fatty acids based on natural vegetable or animal oils having 6 to 30 carbon atoms, in particular having 8 to 22 carbon atoms, such as caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, palmitoleic acid, isostearic acid, stearic acid, 12-hydroxystearic acid, dihydroxystearic acid, oleic acid, linoleic acid, petroselenic acid, elaidic acid, arachidic acid, behenic acid, erucic acid, gadoleic acid, linolenic acid, eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid, which can be used alone or in a mixture, or the alkyl radical derived from poly-condensation products of hydroxy-functionalized acids, such as poly-12-hydroxystearic acid or polyricinoleic acid.

4. The process as claimed in claim 2 , wherein esters of the general formula I are used

where

n and p are 0,

W is hydrogen,

m is 1 to 28,

o is 1 to 100,

q is 1,

R a is R a1 ═R a11 or R a ═R a2 , where R a11 is defined as in claim 3 .

5. The process as claimed in claim 2 , wherein esters of the general formula I are used

where

n and o are 0,

W is hydrogen,

m is 1 to 28,

B is —CH 2 —CH 2 OH—CH 2 —O— or —CH 2 —CH 2 OR b —CH 2 —O—, where R b is defined as in claim 2 ,

p is 1 to 20,

q is 1,

R a is R a1 ═R a11 or R a ═R a2 , where R a11 is defined as in claim 3 .

6. The process as claimed in claim 2 , wherein esters of the general formula I are used

where

n and o are 0,

W is hydrogen,

m is 1 to 28,

B is —CH 2 —CYZ-CH 2 —O—,

where Y and Z are defined as in claim 2 ,

p is q=1,

R a is R a1 ═R a11 or R a ═R a2 ,

where

R a11 is defined as in claim 3 .

7. The process as claimed in claim 2 , wherein esters of the general formula I are used

where

n is 1,

W is hydrogen or CH 3 ,

m is 0 to 27,

o and p are 0,

R a is R a1 ═R a12 or R a ═R a2 ,

where

R a12 is the hydrocarbon radical of a substituted or unsubstituted, optionally branched alcohol having 2 to 30 carbon atoms, preferably having 6 to 22 carbon atoms, which optionally contains one or more multiple bonds, optionally carries hydroxyl groups, optionally carries hydroxyl groups esterified with carboxylic acids or optionally carries amino, alkylamino or dialkylamino groups.

8. The process as claimed in claim 1 , wherein the esters are prepared using the corresponding esters of volatile alcohols for a transesterification, and are selected from the group consisting of methyl, ethyl, and vinyl esters.

9. The process as claimed in claim 1 , wherein the at least one enzyme is selected from the group consisting of lipases, esterases, proteases, and lipase B from Candida antarctica.

10. The process as claimed in claim 1 , wherein as SiH-polysiloxane a compound of the general formula II

is used where

N a+b+c+d+2=3 to 850,

a is 1 to 800,

b is 0 to 400,

c is 0 to 10,

d is 0 to 10, and

in which the radicals

R1 independently of one another are identical or different and from the following group: saturated or unsaturated, optionally branched alkyl groups having 1 to 30 carbon atoms, alkaryl radicals having 7 to 30 carbon atoms, aryl radicals having 6 to 30 carbon atoms, R2 independently of one another are hydrogen or R1,

R3 independently of one another are identical or different radicals of the general formula IIa.

11. The process as claimed in claim 10 , wherein as SiH-polysiloxane a compound of the general formula II

is used where

N a+b+c+d+2=6 to 160,

a is 2 to 150,

b is 2 to 75,

c is 0,

d is 0, and in which the radicals

R1 independently of one another an alkyl groups having 1 to 4 carbon atoms or phenyl,

R2 independently of one another are hydrogen or R1,

R3 independently of one another are identical or different radicals of the general formula IIa.