Materials: Flexible PVC for Building Product Seals Forms Strong Bond to Rigid PVC

A new series of flexible PVC compounds for coextruded profiles from Teknor Apex, Pawtucket, R.I., reportedly forms strong bonds with rigid PVC substrates, yielding durable seal components for building and construction applications along with the possibility of eliminating the pre-drying step before extrusion.

The key to the seal durability provided by these new Apex compounds is formulation technology developed by Teknor Apex that enhances adhesion to rigid PVC. When coextruded onto the substrate, the new compounds exhibit cohesive instead of adhesive bonds, which means that in tests of bond strength the rupture occurs in the flexible PVC rather than at the flexible/rigid interface.

Apex 2310UV2 and 2316UV2 Series compounds are available with a Shore A hardness range from 60 to 80 in both general-purpose and “California Proposition 65-compliant” grades, respectively. The complete series is formulated for UV-resistance to ensure long-term retention of appearance and structural properties, and custom formulations are available with fungicide. Uses for the compounds suggested by the company include window and door seals and other indoor and outdoor applications requiring co-extrusion with rigid vinyl. To complement these flexible products, Teknor Apex also offers a broad range of rigid PVC compounds.