Enhanced weatherability of exterior PVC building products

Poly(Vinyl) Chloride (WC) is used extensively as a material for the growing building-products market. The color preferences of consumers for markets s uch as vinyl siding have forced the industry to seriously reconsider the us e of WC especially for the medium-to-dark color palettes, where the perform ance is critical. Organotin mercaptides have always been the stabilizers of choice :in the U.S. market because of their inherent outstanding heat-stab ilization properties. On the other hand, this technology is also known to b e a compromise between processability and weathering characteristics. In a market that drives for excellence, all additives must be optimized to meet the final performance requirement. Organotin carboxylates and specifically maleates have long been known for excellent weathering but have not been us ed extensively in the industry owing to less-than-optimum intrinsic heat st abilization efficiency, and in some cases, troublesome lachrymatory propert ies. A new generation of organotin maleates has been successfully developed to address both issues. This paper describes the improved lachrymatory beh avior of the new technology compared to standard organotin maleates and als o shows its outstanding weathering performance in PVC capstock compared wit h conventional organotin mercaptide during natural aging.