Monoallophanates based on alkoxysilane alkyl isocyanates
A monoallophanate can be used in paint or adhesive compositions. The monoallophanate has the formula 1: where R, R 1 -R 6 are each independently identical or different hydrocarbyl radicals having 1-8 carbon atoms, which may be branched or cyclic, or else may be integrated together to form a cyclic system, and m and n are each independently 0-2.
1. A monoallophanate having the formula (1):
wherein
R, R 1 -R 6 are each independently identical or different hydrocarbyl radicals having 1-8 carbon atoms, which may be branched or cyclic, or else may be integrated together to form a cyclic system, and
m and n are each 0.
2. The monoallophanate according to claim 1 , wherein
R 1 and R 5 are each independently methyl or ethyl.
3. The monoallophanate according to claim 1 , wherein
R 2 and R 4 are each independently methyl or propyl.
4. The monoallophanate according to claim 1 , wherein
R 1 =R 5 and R 2 =R 4 .
5. The monoallophanate according to claim 1 , wherein
R 1 and R 5 are each methyl or ethyl, and
R 2 and R 4 are each methyl or propyl.
6. The monoallophanate according to claim 1 , wherein
R 1 =R 5 =methyl, and
R 2 =R 4 =propyl.
7. A process for preparing the monoallophanate according to claim 1 , the process comprising:
reacting
A) an isocyanate comprising at least one alkoxysilane group
with
B) a monourethane comprising at least one alkoxysilane group,
at temperatures in the range from 20 to 220° C.
8. The process for preparing the monoallophanate according to claim 7 ,
wherein the monourethane of B) is represented by formula (3):
R n (OR 1 ) 3-n Si—R 2 —NH—(C=O)—OR 3 (3)
wherein
R, R 1 , R 2 and R 3 are each independently identical or different hydrocarbyl radicals having 1-8 carbon atoms, which may be branched or cyclic, or else may be integrated together to form a cyclic system.
9. The process for preparing the monoallophanate according to claim 8 , wherein
R 2 is methyl or propyl, and
R 1 is methyl or ethyl and R 3 =R 1 .
10. The process for preparing the monoallophanate according to claim 8 , wherein
the monourethane of B) is N-trimethoxysilylpropylmethyl carbamate.
11. The process for preparing the monoallophanate according to claim 7 ,
wherein the isocyanate of A) is represented by formula (2):
R 6 m (OR 5 ) 3-m Si—R 4 —NCO (2)
wherein
R 6 , R 5 and R 4 are each independently identical or different hydrocarbyl radicals having 1-8 carbon atoms, which may be branched or cyclic, or else may be integrated together to form a cyclic system.
12. The process for preparing the monoallophanate according to claim 11 , wherein
R 4 is methyl or propyl, and
R 5 is methyl or ethyl.
13. The process for preparing the monoallophanate according to claim 11 , wherein
the isocyanate of A) is isocyanatopropyltrimethoxysilane.
14. A paint composition, which comprises the monoallophanate according to claim 1 .
15. An adhesive composition, which comprises the monoallophanate according to claim 1 .