Protected air-activated organotin catalysts for polyurethane synthesis and processes therefore
AssigneeE. I. Du Pont de Nemours and Company
InventorsJerald Feldman, Stephan J. Mclain, Robert John Barsotti, James William O'Neil
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Abstract
This invention relates to a protected organotin-based catalyst system for polyurethane synthesis that is useful in coatings applications. The catalyst has low activity in the absence of oxygen. When a coating mixture comprising the catalyst is sprayed and/or applied to a substrate as a thin film in air, the catalyst is activated. For solvent-based refinish systems comprising hydroxyl and isocyanate species at high solids levels, the catalyst system therefore provides extended viscosity stability, i.e., pot life.
Claims16
A process for polyurethane synthesis comprising the steps of:
- a) providing a catalyst of the formula R1aR2bR3cSn[CH(OX)R4]d,
- wherein R1, R2, and R3 are the same or different and represent an optionally substituted hydrocarbyl, aromatic, alkoxide, amide, halide or stannyl group, R4 represents an optionally substituted hydrocarbyl or optionally substituted aryl group. a, b, and c are independently 0, 1, 2, or 3;
- d is 1, 2 or 3;
- and a+b+c+d=4;
- and X is an acid or moisture-labile protecting group;
- b) contacting at least one isocyanate with the catalyst of step a) to form a blend;
- c) contacting the blend of step b) to at least one polyol to form a mixture;
- and
- d) optionally exposing the mixture of step c) to air or a gas comprising oxygen.
A process for polyurethane synthesis comprising the steps of:
- a) providing a catalyst of the formula R1aR2bR3cSn[CH(OX)R4]d,
- wherein R1, R2, and R3 are the same or different and represent an optionally substituted hydrocarbyl, aromatic, alkoxide, amide, halide or stannyl group, R4 represents an optionally substituted hydrocarbyl or optionally substituted aryl group. a, b, and c are independently 0, 1, 2, or 3;
- d is 1, 2 or 3;
- and a+b+c+d=4;
- and X is an acid or moisture-labile protecting group;
- b) contacting at least one polyol with the catalyst of step a) to form a blend;
- c) contacting the blend of step b) to at least one isocyanate to form a mixture;
- and
- d) optionally exposing the mixture of step c) to air or a gas comprising oxygen.
Dependencies are inferred from the claim text.