Polyurethane resins
AssigneeDekro Paints (Proprietary) Limited
InventorsKibret Mequanint, Ronald Douglas Sanderson
Life of this patent
Estimating the term…
Abstract
A polyurethane resin consists of a reaction product of a phosphated polyol, a polyisocyanate and optionally a stabilizing monomer having a salt-forming group, for example, 2,2-dimethyolol propionic acid. The phosphated polyol may be a hydroxyl-terminated, phosphated polyester polyol which is a reaction product of a carboxylic acid, a polyol and a phosphate monomer. The phosphate monomer may be 2-phosphonobutane-1,2,4-tricarboxylic acid. The invention provides aqueous dispersions of phosphated polyurethane resins which are particularly suitable as metal primers for metals such as galvanised steel. The metal primers have improved adhesion under agressive enviroments.
Claims21
A segmented non-crosslinked polyurethane resin which is dispersible in water, the polyurethane resin comprising a reaction product of:
- a first component comprising at least one phosphated polyester polyol containing at least one covalent C—P bond, the phosphated polyester polyol being a hydroxyl-terminated, phosphated polyester polyol which is a reaction product of at least one carboxylic acid, at least one polyol and 2-phosphonobutane-1,2,4-tricarboxylic acid;
- a second component comprising at least one polyisocyanate;
- and
- a third component comprising at least one stabilising monomer having at least one salt-forming group.
A method of preparing a segmented non-crosslinked polyurethane resin which is dispersible in water, which method comprises the steps of reacting together a first component comprising at least one phosphated polyester polyol containing at least one covalent C—P bond, the phosphated polyester polyol being a hydroxyl-terminated, phosphated polyester polyol which is a reaction product of at least one carboxylic acid, at least one polyol and 2-phosphonobutane-1,2,4-tricarboxylic acid;
- a second component comprising at least one polyisocyanate, and a third component comprising at least one stabilising monomer having at least one salt-forming group.
Dependencies are inferred from the claim text.