Patent ID: 8940370
Filing Date: 2015-01-27
Classification: C08G,C09D

Abstract:
1. A process for the preparation of the outer top coat layer of an automotive Original Equipment Manufacture multi-layer coating comprising the steps: (1) providing an automotive substrate to be Original Equipment Manufacture top coated, (2) preparing an aqueous two-component polyurethane top coating composition by static mixing a non-aqueous hydrophobic polyisocyanate crosslinker component and an aqueous binder component having a binder solids content comprising at least one water-dilutable hydroxyl-functional binder, (3) spray-applying the aqueous two-component polyurethane top coating composition on the automotive substrate to be Original Equipment Manufacture top coated, and (4) thermally curing the top coat layer applied in step (3), wherein the binder solids content of the aqueous binder component comprises 5 to 30 wt.-% of at least one urethane compound A with at least two terminal urethane groups (—NHC(O)OR; R=hydrocarbyl residue of a monoalcohol) and having a number-average molar mass (Mn) of from 400 to 5,000, and wherein the binder solids content consists of 5 to 30 wt.-% of the at least one urethane compound A and 70 to 95 wt.-% of the at least one water-dilutable hydroxyl-functional binder, wherein the sum of the wt.-% totals 100 wt.-%.