PPG Awarded patent
for multi-layer coatings
Patent No. U.S. 6,589,603 B1
PPG Industries has been granted a patent for a process for forming and drying a multilayer composite coating on an elongated three-dimensional multi-faced extrusion substrate. The process is comprised of passing the substrate to a first coating station located on a coating line; applying a base coating composition to the entire exterior surface of the substrate as it passes through the first coating station, thereby forming a base coat on the substrate; passing the substrate from the second step to a first drying station located on the coating line; drying the base coat as it passes through the first drying station; passing the substrate to a second coating station located on the coating line; applying a top coating composition, different from the base coating composition, to at least one but not all of the faces of the substrate as it passes through the second coating station to form a top coat on a portion of the substrate; passing the substrate to a second drying station located on the coating line; and drying the top coat as it passes through the drying station.