Polymer containing silane groups
A polymer containing silane groups, a method for synthesizing same, and curable compositions including the polymer. The polymer containing silane groups has a very long shelf life and cures quickly with moisture. The polymer is suitable as an elastic adhesive or sealant or coating that can be applied at room temperature and has good heat resistance, or as a hot melt adhesive.
1. A polymer having end groups of the formula (I)
where
either R′ is a radical of the formula (II) and R″ is a hydrogen radical
or R′ is a hydrogen radical and R″ is a radical of the formula (II);
R 1 is a hydrocarbyl radical which has 1 to 18 carbon atoms and optionally has heteroatoms in the form of ether oxygen, ester oxygen, thioether sulfur or tertiary amine nitrogen;
R 2 is a linear or branched alkylene or cycloalkylene radical having 1 to 20 carbon atoms, optionally having aromatic components, and optionally having one or more heteroatoms;
R 3 is an alkyl radical having 1 to 8 carbon atoms;
R 4 is an aliphatic or cycloaliphatic or arylaliphatic hydrocarbyl radical which has 1 to 12 carbon atoms and optionally has one or two ether oxygens;
X is O or S; and
n is 0 or 1 or 2.
2. A polymer as claimed in claim 1 , characterized in wherein R 1 is an aliphatic or cycloaliphatic or arylaliphatic hydrocarbyl radical which has 1 to 12 carbon atoms and optionally has one or two ether oxygens.
3. A polymer as claimed in claim 1 , wherein R 4 is a methyl radical or an ethyl radical.
4. A polymer as claimed in claim 1 , wherein X is O.
5. A polymer as claimed in claim 1 , wherein X is O and R 1 and R 4 are each a methyl radical or are each an ethyl radical.
6. A polymer as claimed in claim 1 , wherein n is 0.
7. A polymer as claimed in claim 1 , wherein it has an average functionality in the range from 1.3 to 4 in relation to end groups of the formula (I).
8. A polymer as claimed in claim 1 , wherein it has an average molecular weight in the range from 1′000 to 30′000 g/mol.
9. A polymer as claimed in claim 1 , wherein it is a polyether containing silane groups which is liquid at room temperature.
10. A polymer as claimed in claim 1 , wherein it is a polyester which is solid at room temperature and/or a polycarbonate which is solid at room temperature.
11. A process for preparing a polymer as claimed in claim 1 , wherein at least one hydroxysilane of the formula (III)
is reacted with at least one polyurethane polymer containing isocyanate groups.
12. A curable composition comprising at least one polymer as claimed in claim 1 .
13. The curable composition as claimed in claim 12 , wherein it is applicable at room temperature and is an elastic adhesive or sealant or an elastic coating.
14. The curable composition as claimed in claim 12 , wherein it is solid at room temperature and is a hotmelt adhesive.
15. A hydroxysilane of the formula (VII)
where
either R 5 is a radical of the formula (VIII) and R 6 is a hydrogen radical
or R 5 is a hydrogen radical and R 6 is a radical of the formula (VIII);
—(CH 2 ) 2 Si(OR 8 ) 3 (VIII)
and R 7 and R 8 are either each a methyl radical or each an ethyl radical.