Use of polyethers containing urethane for urea groups for stabilizing polyurethane foams

1. A method of stabilizing a foam which comprises adding polyethers containing urethane or urea groups as foam stabilizers during the process of making the foam, wherein the polyethers containing urethane or urea groups is obtained by reacting

A. at least one isocyanate with

B. (a) at least one hydrophilic polyether which statistically carries at least one OH and/or NH 2 and/or NH function and

 (b) at least one hydrophobic polyether which statistically carries at least one OH and/or NH 2 and/or NH function and optionally

 (c) further compounds which carry at least one OH and/or NH 2 and/or NH function and/or other isocyanate-reactive groups,

with the proviso that at least one isocyanate A is ≧difunctional;

wherein at least one polyether of the general formula (I)

(R 1 ) a [R 2 [(E) c -(P) d —R 3 ] b ] e   (I)

in which,

R 1 , in the case of a=1, is an e-functional nonreactive moiety of an initiator,

R 2 , independently of one another, are O, NR 4 , NH or N,

E is an ethoxy function,

P are identical or different alkoxy function(s) having at least three carbon atoms,

R 3 are identical or different radicals from the group consisting of H, —C f H 2f —N(R 4 )H and —C f H 2f —NH 2 ,

R 4 are identical or different alkyl or aryl functions having 1 to 20 carbon atoms,

a is 0or 1,

b is 1, 2 or 3,

c is from 10 to 500,

d is from 0 to 330,

e is from 1 to 10,

f is from 2 to 5,

with the proviso that

c>0.6 (c+d),

is used as component a).

2. The method of claim 1 , wherein at least one polyether of the general formula (I), in which

c is from 0 to 400,

d is from 10 to 500,

with the proviso that

c<0.45 (c+d),

is used as component b).

3. The method of claim 1 , wherein at least one polyether of the general formula (I), in which

c is from 15 to 400,

d is from 0 to 200,

e is from 2 to 8,

is used as component a).

4. The method of claim 1 , wherein at least one polyether of the general formula (I), in which

c is from 20 to 300,

d is from 0 to 100,

e is from 2 to 4,

is used as component a).

5. The method of claim 1 , wherein at least one polyether of the general formula (I), in which

c is from 0 to 300,

d is from 15 to 400,

e is from 2 to 8,

is used as component b).

6. The method of claim 1 , wherein at least one polyether of the general formula (I), in which

c is from 0 to 200,

d is from 20 to 300,

e is from 2 to 4,

is used as component b).

7. The method of claim 1 , wherein at least one polyether of the formulae

is used as component a).

8. The method of claim 1 , wherein at east one polyether of the formulae

is used as component b).

9. The method of claim 1 , wherein polyesterdiols are used as component c).

10. The method of claim 1 , wherein

B. is (a) at least one hydrophilic polyether which statistically carries at least one OH and/or NH 2 and/or NH function and

 (b) at least one hydrophobic polyether which statistically carries at least one OH and/or NH 2 and/or NH function and optionally

 (c) further compounds which carry at least one OH and/or NH 2 and/or NH function and/or carboxyl or epoxide functional groups.

11. The method of claim 1 , wherein

E is an ethoxy function which is the radical —(CH2-CH2-O), and

R 4 are identical or different and are selected from the group consisting of methyl, ethyl and phenyl.