Surface-modified silicic acid semi-gels

1. A surface-modified semi-gel, comprising:

a silicon dioxide semi-gel having a surface modified with 0.2% to 12% by weight relative to the silicon dioxide semi-gel of at least one of a silicone polyether acrylate polymer and a silicone polyether methacrylate polymer;

wherein

the semi-gel is in the form of a particulate structure;

a mesopore volume for pores having a diameter of 2-30 nm of the surface-modified silicon dioxide semi-gel is 0.7 to 1.5 ml/g; and

a mesopore volume for pores having a diameter of 2-50 nm of the surface-modified silicon dioxide semi-gel is 0.9 to 1.8 ml/g.

2. The surface-modified semi-gel of claim 1 , wherein:

a BET surface area of the surface-modified silicon dioxide semi-gel is 200 to 400 m 2 /g; and

a pore maximum of the surface-modified silicon dioxide semi-gel is from 10 to 50 nm.

3. An article, comprising the surface-modified semi-gel of claim 1 , wherein the article is at least one selected from the group consisting of a matting agent in a paint, a matting agent in a coating, a constituent of a paper coating, a defoamer formulation, a reinforcing agent in silicone rubber, a reinforcing agent in a plastic, and an antiblocking agent.

4. A coating formulation, comprising the surface-modified semi-gel of claim 1 .

5. The surface-modified semi-gel of claim 1 , wherein the at least one of a silicone polyether acrylate polymer and a silicone polyether methacrylate polymer is obtained by esterification or transesterification of acrylic acid, methacrylic acid, an acrylic ester, a methacrylic ester, or a mixture thereof, in the presence of an enzyme which catalyses the esterification or transesterification with at least one hydroxy-functional and/or polyoxyalkylene-modified siloxane derivative of formula (III):

wherein:

R 1 , R 7 , or both R 1 and R 7 , represent R 2 or [R 4 ] w —[R 5 ] x —[R 6 ] y —R 8 ;

R 2 and R 3 individually represent identical or different alkyl radicals, alkylene radicals having 1 to 24 carbon atoms, or substituted phenyl radicals having up to 24 carbon atoms;

R 4 represents a divalent radical of the formula O, NH, NR 2 , S or a radical of the formula (OSi(CH 3 ) 2 ) u ;

u=1 to 200;

R 5 represents identical or different alkyl radicals or alkylene radicals having 1 to 24 carbon atoms, or C n H 2n-f R 2 f —R 4 —C m H 2m-g R 2 g ;

f=0 to 12;

g=0 to 12;

n=1 to 18;

m=1 to 18;

R 6 =O—(C 2 H 4-a R 2 a O) b (C c H 2c O) d ;

a=0 to 3;

b=0 to 100;

c=2 to 12;

d=0 to 100;

a sum of (b+d)=1 to 200;

a sequence of individual polyoxyalkylene segments (C 2 H 4-a R 2 a O) b and (C c H 2c O) d optionally comprises a block copolymer;

R 6 =O e —C h H 2h —C i H 2i-j R 9 j ;

e=0 or 1;

h=0 to 24;

i=0 to 24;

j=1 to 3;

a sum of (w+e)=0 to 1;

R 9 represents a divalent radical of the formula O, a hydroxyl group, a radical of the formula C h H 2h , or a radical of formula C k H 2k-l (OH) l ;

k=0 to 24;

l=1 to 3;

R 8 =a hydrogen radical or a monovalent organic radical;

when y is 1, at least one hydrogen radical, OH group, or monovalent organic radical is present per molecule;

when y=0, at least one OH group is present per molecule;

v=0 to 200;

w=0 or 1;

x=0 or 1;

y=0 or 1;

z=0 to 200;

a sum of (w+x+y)=1 to 3;

when z=0,

R 1 , R 7 , or both R 1 and R 7 , are [R 4 ] w —[R 5 ] x —[R 6 ] y —R 8 ; and

when x=0, then w=0.

6. The surface-modified semi-gel of claim 1 , wherein a BET surface area of the surface-modified semi-gel is 200 to 350 m 2 /g.

7. The surface-modified semi-gel of claim 1 , wherein a mesopore volume for pores having a diameter of 2-30 nm of the surface-modified semi-gel is 0.95 to 1.4 ml/g.

8. The surface-modified semi-gel of claim 1 , wherein a mesopore volume for pores having a diameter of 2-50 nm of the surface-modified semi-gel is 1.0 to 1.7 ml/g.

9. The surface-modified semi-gel of claim 1 , wherein a pore maximum of the surface-modified semi-gel is 15 to 45 nm.

10. A process for preparing the surface-modified semi-gel of claim 1 , the process comprising contacting the surface of the semi-gel with the at least one of a silicone polyether acrylate polymer and a silicone polyether methacrylate polymer.

11. The process of claim 10 , wherein:

surface modification occurs during at least one time selected from the group consisting of before, after, and simultaneously with a grinding operation; and

the grinding operation employs an air-jet mill, steam jet mill, or opposed-jet fluidized-ed mill.

12. The process of claim 10 , wherein the at least one of a silicone polyether acrylate polymer and a silicone polyether methacrylate polymer is added in pure, undiluted form or in dilute form as an aqueous emulsion.

13. The process of claim 10 , wherein:

a BET surface area of the surface-modified semi-gel is 200 to 400 m 2 /g;

a mesopore volume for pores having a diameter of 2-30 nm of the surface-modified semi-gel is 0.95 to 1.5 ml/g;

a mesopore volume for pores having a diameter of 2-50 nm of the surface-modified semi-gel is 1.2 to 1.8 ml/g; and

a pore maximum of the surface-modified semi-gel is in the range from 10 to 50 nm.

14. The process of claim 10 , further comprising drying the surface-modified semi-gel.