Composition comprising block cocondensates of propylfunctional alkaline siliconates and silicates, and method for the production thereof

1. A composition, comprising:

a water-soluble block cocondensate of at least one alkali metal propylsiliconate with at least one alkali silicate and water,

wherein

the block cocondensate has crosslinking structural elements which form catenary, cyclic, crosslinked and/or three-dimensionally crosslinked structures, and

at least one structure corresponds to formula I,

MO[[Si(R 1 ) x Y ((y-2)-x) O] a [Si(Y) 2 ] b [Si(R 1 ) x Y ((y-2)-x) O] c ] n [[Si(Y) 2 ] m ]OM  (I),

where

R 1 is a propyl radical,

each Y is independently OM or OH, or O 1/2 in crosslinked and/or three-dimensionally crosslinked structures, each M is independently an alkali metal ion,

each x is independently 1 or 2,

each y is independently 3 or 4, where (x+y)=4, and

a≧1, c≧0, b≦0, n≧1, m≧2, where (b+m)=v and (a+c)/v≦1,

wherein the block cocondensate is present in a mixture with at least one monomeric alkali metal propylsilanolate and at least one alkali metal silicate.

2. The composition according to claim 1 ,

wherein

b≧1, and

independently at each occurrence c≧1.

3. The composition according to claim 1 ,

wherein, independently at each occurrence:

a≧1,

c≧1,

b≧1,

n≧1,

m≧2,

(b+m)=v and v≧4, and

(a+c)/v≦1.

4. The composition according to claim 1 ,

wherein

the composition is substantially alcohol-free and no longer releases substantially any alcohol during crosslinking.

5. A process for preparing a composition of claim 1 , the process comprising:

(i) reacting a mixture comprising propylalkoxysilane and optionally propyl-functional siloxanes derived

from a propylsilane of formula II

(R 1 ) x SiX (y-x)   (II),

where R 1 is independently a propyl-functional radical, X is independently alkoxy or a halogen, x is 1 or 2 and y is 4,

and optionally from a hydrolysable silane of formula III

SiY 4   (III),

where Y is independently an alkoxy or a halogen, and

(ii) reacting a mixture of at least one water-soluble silicate and an aqueous alkaline solution,

thereby obtaining the composition, which comprises a substantially water-soluble block cocondensate of at least one alkali metal propylsiliconate with at least one alkali metal silicate and water.

6. The process according to claim 5 ,

wherein

the water-soluble silicate is an alkali metal silicate.

7. The process according to claim 5 ,

wherein

the aqueous alkaline solution comprises an alkali metal hydroxide.

8. The process according to claim 5 ,

wherein

in said reacting (i),

a mixture comprising propylalkoxysilane and optionally—a siloxane is prepared by reacting a propylsilane of formula II, where X is halogen, with an alcohol, optionally in the presence of water, and removing the alcohol and/or hydrolysis alcohol,

or

a mixture comprising propylalkoxysilane, tetraalkoxysilane, and optionally a cocondensate thereof is prepared by reacting at least one propylsilane of formula II, where X is halogen, and at least one hydrolysable silane of formula III, where Y is halogen, with an alcohol, optionally in the presence of water, and removing the alcohol and/or hydrolysis alcohol.

9. The process according to claim 5 ,

wherein

X of formula II is independently a methoxy, ethoxy, propoxy, butoxy, chloro, or bromo, and

Y of formula III is independently a methoxy, ethoxy, propoxy, butoxy, chloro, or bromo.

10. The process according to claim 5 ,

wherein

a mixture derived from a propylhalosilane of formula II and optionally from a tetrahalosilane of formula III is added to the mixture of a water-soluble silicate in the aqueous alkaline solution.

11. The process according to claim 5 ,

wherein

the propylsilane of formula II and the silane of formula III are used in a molar ratio of from 1:0 to 3:1.

12. The process according to claim 8 ,

wherein

the alcohol is added in a molar ratio of from 0.001:1 to 100:1 relative to hydrolysable radicals.

13. The process according to claim 5 ,

wherein

hydrolysis alcohol formed in said reacting (i) is removed.

14. The process according to claim 5 ,

wherein

a fraction of the water-soluble block cocondensate in the composition is from 1 to 60 wt %, based on a total weight of the composition is optionally adjusted by addition of water.

15. The composition according to claim 1 , which has a pH≧11.