Flexible PVC for Building-Product Seals Forms Strong Bond to Rigid PVC While Potentially Eliminating a Pre-Drying Step

February 21, 2019

Apex® 2310UV2 and 2316UV2 Compounds from Teknor Apex Are UV- and Fungus-Resistant and Are Available in “California Proposition 65-Compliant” Formulations  

A new series of flexible PVC compounds for co-extruded profiles forms strong bonds with rigid vinyl substrates, yielding durable seal components for building and construction applications along with the possibility of eliminating the pre-drying step before extrusion.

Apex® 2310UV2 and 2316UV2 Series compounds from Teknor Apex Company 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 Teknor Apex 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, making it possible to purchase a complete system from one supplier.

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.

“The bond to rigid PVC is stronger than the inherent strength of the flexible PVC itself,” said John E. Macaluso, building and construction industry manager for the Vinyl Division of Teknor Apex. “While pre-drying the flexible PVC always helps to increase the strength of the bond with rigid vinyl, the excellent bond achieved with our new compounds potentially eliminates the need for the pre-drying step.”