Silicone (meth)acrylates, process for their preparation and their use in curable compositions

1 . A method for preparing silicone (meth)acrylates, comprising:

reacting at least one acetoxy silicone with at least one hydroxy-functional (meth)acrylic ester.

2 . The method according to claim 1 , wherein the at least one acetoxy silicone is a compound of formula (I),

M m1 M AcO m2 D d1 D AcO d2 T t Q q   formula (I),

where

M=[R 3 SiO 1/2 ];

M AcO =[R 2 (AcO)SiO 1/2 ];

D=[R 2 SO 2/2 ];

D AcO =[R(AcO)SiO 2/2 ];

T=[RSiO 3/2 ];

Q=[SiO 4/2 ];

m1=0 to 32;

m2=0 to 32;

d1=1 to 1000;

d2=0 to 10;

t=0 to 10;

q=0 to 10;

in which

R is in each case independently a monovalent organic radical;

AcO is an acetoxy group;

with the proviso that:

m1+m2=at least 2;

m2+d2=at least 1.

3 . The method according to claim 1 , wherein the at least one acetoxy silicone is produced by reacting

silanes and/or siloxanes bearing alkoxy groups, and/or

silanes and/or siloxanes bearing acetoxy groups, and/or

silanes and/or siloxanes bearing hydroxyl groups, and/or

simple siloxane cycles and/or DT cycles,

with acetic anhydride and, as catalyst, at least one Brønsted acid having a pKa of ≤−1.3.

4 . The method according to claim 3 , wherein the at least one Brønsted acid is neutralized with a base prior to further reaction with the at least one hydroxy-functional (meth)acrylic ester.

5 . The method according to claim 1 , wherein the at least one hydroxy-functional (meth)acrylic ester is a compound of the formula (I),

wherein

x=at least 1;

in which

R 1 is in each case independently a (x+1)-valent organic radical, and

R 2 is in each case independently a hydrogen radical or a methyl radical.

6 . The method according to claim 1 , wherein a molar ratio of hydroxyl groups of the at least one hydroxy-functional (meth)acrylic ester to acetoxy groups of the at least one acetoxy silicone is at least 1.00.

7 . The method according to claim 1 , wherein the at least one acetoxy silicone is reacted with the at least one hydroxy-functional (meth)acrylic ester in the presence of at least one catalyst selected from the group consisting of

Brønsted acids having a pKa of <−3;

Lewis acids; and

metal catalysts.

8 . The method according to claim 1 , wherein the reaction of the at least one acetoxy silicone with the at least one hydroxy-functional (meth)acrylic ester is carried out at a temperature of 40° C. to 150° C., over a period of one to 8 hours.

9 . The method according to claim 1 , wherein a reaction product is freed of volatile constituents over 1 to 8 hours, at a temperature of 80° C. to 140° C., under application of a vacuum of less than 200 mbar.

10 . The method according to claim 1 , wherein acids present in a reaction product are neutralized at a temperature of 20° C. to 110° C., by adding a solid, liquid or gaseous base.

11 . The method according to claim 7 , wherein the Brønsted acids are selected from the group consisting of trifluoromethanesulfonic acid, methanesulfonic acid, para-toluenesulfonic acid, and trifluoroacetic acid; and

wherein the metal catalysts are selected from the group consisting of titanium tetrabutoxide, zinc acetylacetonate, and zinc carboxylate.