Treating the surface of wood-plastic composite (WPC) boards with fluorine gas in the presence of oxygen oxidizes the surface so that ordinary paints and primers adhere as they do to natural wood.

Treating the surface of wood-plastic composite (WPC) boards with fluorine gas in the presence of oxygen oxidizes the surface so that ordinary paints and primers adhere as they do to natural wood. Typical fluorination is done in the absence of oxygen to impart barrier properties. But Fluoro-Seal International L.P. in Houston discovered that fluorination with oxygen creates oxidation. Paint adhesion was measured by the ASTM cross-hatch adhesion test. Nontreated WPC lumber had adhesive bond strength of 72 g/cm2 vs. 182 g/cm2 for the treated sample. (Photos show paint flaking paint off the untreated sample but adhering well to the treated sample.) Fluoro-Seal is working with WPC technology company Strandex Corp. of Madison, Wis., to develop continuous off-line treatment and priming of wood-HDPE products for market testing. Reacted fluorine gases are removed after use by scrubbing with activated alumina.

Fluoro-Seal International, L.P
16360 Park Ten Place # 325 Houston, TX 77084-5046
Phone (281) 578-1440 Fax (281) 578-3159