Siliconized polyether thermosetting coating compositions

摘要

Pigmented thermosetting organic solvent solution coating compositions are disclosed which cure to provide improved weather resistance. These coating compositions contain three resin components, as follows: (1) an essentially nonfunctional organic solvent-soluble silicone resin reaction product of a low molecular weight hydroxy functional polyether with an hydroxy or alkoxy-functional organic polysiloxane, said polyether having an average molecular weight in the range of 300 to 4000 and an hydroxy functionality of at least about 3, said polysiloxane being present in an amount of from 8% to 20% of the weight of the three resin components, and said polyether and said polysiloxane being combined in approximately stoichiometric proportions; (2) a reactive organic solvent-soluble essentially linear high molecular weight hydroxy functional polyester constituting the balance of the three resin components; and (3) from 3% to 15% of the three resin components of a heterocyclic aminoplast resin for curing the reactive polyester. Components 1 and 2 are compatible in the solution and at least partially incompatible in a film as the solvent evaporates, so that component 1 can concentrate at the surface to enhance the weather resistance.