Rapid-cure, one-component mixtures, which contain alkoxysilane-terminated polymers
View Patent ↗One-component, moisture curing compositions which exhibit rapid curing, even with exceptionally low levels of catalyst or with no catalyst at all, can be formulated from alkoxysilane-terminated polymers having alkoxysilane groups bonded to an electronegative, free electron-pair-containing heteroatom via a methylene linking group. Polymer blends containing the alkoxysilane-terminated polymers exhibit rapid cure, even at room temperature, and allow the use of nitrogen containing components such as adhesion promoters.
1. A moisture curable, non-aqueous, alkoxy-crosslinking one-component polymer blend comprising at least one alkoxysilane-terminated polymer (A) having end groups of the formula (1)
-A-CH 2 —SiR 1 a (OR 2 ) 3-a (1)
and, optionally, one or more tin catalysts in an amount of not more than 100 ppm Sn, based on the weight of the polymer blend, where
A is an —O—, —S—, —(R 3 )N—, O—CO—N(R 3 )—, or —N(R 3 )—CO—O—, divalent linker group,
R 1 is an optionally halogen-substituted alkyl, cycloalkyl, alkenyl or aryl radical having 10 carbon atoms or less,
R 2 is an alkyl radical having 1–6 carbon atoms or an ω-oxyalkyl-alkyl radical having in total 2–10 carbon atoms,
R 3 is hydrogen, an optionally halogen-substituted cyclic, linear, or branched C 1 to C 18 alkyl, C 2-18 alkenyl, or C 6 to C 18 aryl radical, and
a is an integer from 0 to 2,
with the proviso that said polymer blend is not:
a foamable mixture comprising an isocyanate-free, alkoxysilane-terminated prepolymer of the formula [2],
—X—CO—Y—CH 2 —SiR α w (OR β ) 3-w [2]
in which
X and Y are an oxygen atom, an NRγ group or a sulfur atom,
R α is an alkyl, alkenyl or aryl radical having 1–10 carbon atoms,
R β is an alkyl radical having 1–2 carbon atoms or an ω-oxyalkyl-alkyl radical having in total 2–10 carbon atoms,
Rγ is a hydrogen atom, an alkyl, cycloalkyl, alkenyl or aryl radical having less than 10 carbon atoms or a CH 2 —SiR α w (OR β ) 3-w group, and
w is 0 or 1,
where at least one of the two groups, X or Y, is an NH function, and at least one propellant.
2. The polymer blend of claim 1 , which is free from tin catalyst.
3. The polymer blend of claim 1 , which is free from heavy metal catalyst.
4. The polymer blend of claim 1 , in which the radicals R 1 are independently methyl, ethyl or phenyl radicals.
5. The polymer blend of claim 2 , in which the radicals R 1 are independently methyl, ethyl or phenyl radicals.
6. The polymer blend of claim 3 , in which the radicals R 1 are independently methyl, ethyl or phenyl radicals.
7. The polymer blend of claim 1 , in which the radicals R 2 independently are methyl or ethyl radicals.
8. The polymer blend of claim 2 , in which the radicals R 2 independently are methyl or ethyl radicals.
9. The polymer blend of claim 1 , further comprising a water scavenger.
10. The polymer blend of claim 1 , further comprising a water scavenger and a filler.
11. The polymer blend of claim 1 , in which each A independently is a divalent linker group —O—CO—N(R 3 )— or N(R 3 )—CO—O—.
12. The polymer blend of claim 2 , in which each A independently is a divalent linker group —O—CO—N(R 3 )— or N(R 3 )—CO—O—.
13. The polymer blend of claim 3 , in which each A independently is a divalent linker group —O—CO—N(R 3 )— or N(R 3 )—CO—O—.
14. The polymer blend of claim 4 , in which each A independently is a divalent linker group —O—CO—N(R 3 )— or N(R 3 )—CO—O—.
15. The polymer blend of claim 7 , in which each A independently is a divalent linker group —O—CO—N(R 3 )— or N(R 3 )—CO—O—.
16. The polymer blend of claim 1 , wherein polymer (A) is a reaction product of at least one silane of the formula (5)
OCN—CH 2 —SiR 1 a (OR 2 ) 3-a (5)
with an isocyanate-reactive prepolymer.
17. The polymer blend of claim 1 , further comprising at least one organic amino compound as a basic catalyst.
18. The polymer blend of claim 17 , wherein at least one basic catalyst comprises a compound of the formula (7)
Z-R 4 —SiR 1 a (OR 2 ) 3-a (7)
where
Z is an NHR 3 group and
R 4 is a branched or unbranched hydrocarbon radical having 1–10 carbon atoms optionally interrupted by oxygen or N(R 3 ) groups.
19. An adhesive or sealant composition, comprising the polymer blend of claim 1 .
20. A surface coating or molding composition, comprising the polymer blend of claim 1 .