BUILDING & CONSTRUCTION
Siding and Window Profile
Rigid PVC is widely used in siding and window profile applications. The use of a thermal stabilizer is necessary in rigid PVC to prevent degradation during high temperature molding, extrusion, and calendering operations. Systems based on lead salts are highly effective in rigid PVC, but their use is being phased out around the world due to toxicity concerns. Amfine and its parent company Adeka have been world leaders in the development and commercialization of environmentally-friendly, heavy metal free thermal stabilizers for a variety of rigid PVC applications.
Rigid PVC siding and window profile can be susceptible to chalking, which is associated with the migration of fillers to part surfaces during weathering. Anti-chalking additives are used to prevent this and improve the weatherability of rigid PVC in outdoor applications.
Clear polycarbonate sheet is used as a substitute for glass in applications such as greenhouses, skylights, transit shelters, and covered walkways. Sheet products highly resistant to weathering can be produced by co-extrusion of a thin layer of polycarbonate containing a high concentration of UV absorber over a thicker bulk layer. The capstock protects the bulk layer by absorption of the UV radiation in sunlight. Non-volatile UV absorbers are essential for use in co-extrusion capstock applications to prevent plate-out during sheet extrusion. UV absorbers from Amfine were the first to be developed for this demanding application, providing excellent weatherability as well as very low volatility.