Silane-containing isocyanate-terminated polyurethane polymers
AssigneeUnion Carbide Corporation
InventorsMitchell H. Berger, Walter P. Mayer, Robert J. Ward
Life of this patent
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Abstract
Curable isocyanate prepolymers have been made in which all or a portion of the available isocyanate terminal groups have been reacted with a secondary amine-containing silane monomer having two trialkoxy silane groups.
Claims23
A curable composition comprising the reaction product of an isocyanate terminated polyurethane prepolymer having at least two urethane linkages per polymer molecule and a bis silane, said reaction product having a number average molecular weight of about 750 to about 20,000 and having 2 to about 9 functional groups, per average molecular weight, selected from the group consisting of:
- ##STR10## wherein R is a lower alkyl having 1 to about 6 carbons;
- R.sup.1 is a lower alkyl having 1 to about 4 carbons;
- each of R.sup.2 and R.sup.3 is an alkylene radical having 2 to 18 carbons or arylene radicals having 6 to 18 carbons, and
- a is an integer having values of 0 to 2;
- ##STR11## wherein R, R.sup.1 and a are as above,
- each of R.sup.4 and R.sup.5 is an alkylene radical having 1 to 4 carbons, and
- Q is a monovalent radical selected from the group consisting of hydrogen, alkyl having 1 to 4 carbons, phenyl, --COOR.sup.1 or --CN;
- and ##STR12## wherein R, R.sup.1 and a are as above,
- each of R.sup.7 and R.sup.8 is an alkylene radical having 1 to 4 carbons, and
- Q is a monovalent radical selected from the group consisting of hydrogen, alkyl having 1 to 4 carbons, phenyl, COOR.sup.1 or --CN,
- with the proviso that at least 0.1 percent of the total of said functional groups (1), (2), (3) and (4) is at least one of (2), (3), or (4).
A method of formulating a sealant composition having enhanced wet adhesion which comprises:
- (1) reacting a polyol with a stoichiometric excess of a polyisocyanate to provide an --NCO terminated polyurethane prepolymer;
- and
- (2) end-capping at least 0.1% of said --NCO terminal groups by contacting them with a bis-silane selected from the group consisting of:
- ##STR16## wherein R is a lower alkyl having 1 to about 6 carbons;
- R.sup.1 is a lower alkyl having 1 to about 4 carbons,
- each of R.sup.2 and R.sup.3 is an alkylene radical having 2 to 18 carbons or arylene radicals having 6 to 18 carbons, and
- a is an integer having values of 0 to 2;
- ##STR17## wherein R, R.sup.1 and a are as above,
- each of R.sup.4 and R.sup.5 is an alkylene radical having 1 to 4 carbons, and
- Q is a monovalent radical selected from the group consisting of hydrogen, alkyl having 1 to 4 carbons, phenyl, --COOR.sup.1 or --CN;
- and ##STR18## wherein R, R.sup.1 and a are as above,
- each of R.sup.7 and R.sup.8 is an alkylene radical having 1 to 4 carbons, and
- Q is a monovalent radical selected from the group consisting of hydrogen, alkyl having 1 to 4 carbons, phenyl, COOR.sup.1 or --CN.
Dependencies are inferred from the claim text.