Exxon Mobil Chemical has commercialized a new Santoprene™ thermoplastic vulcanizate (TPV) exterior weatherseal grade for automotive and construction corner moldings. Used to join ethylene propylene diene monomer (EPDM) or TPV weatherseal profiles, Santoprene TPV B200 provides excellent adhesion, versatile aesthetics, rubbery touch and critical performance at reduced cost. Santoprene TPV B200 offers an enhanced bond to EPDM or TPV profiles for more reliable corner seals. Requiring no adhesives or mechanical interlocks, the improved adhesion of this TPV is a result of the unique interaction of the materials during cooling. The bond is designed to last the lifetime of the car over a wide range of temperatures.
"The improved adhesion of Santoprene TPV B200 is critical as traditional corner molding products have not provided the desired bond to EPDM," said Eric Jourdain, automotive weatherseal segment manager, ExxonMobil Chemical specialty elastomers. "We've met that challenge by creating a TPV-to-EPDM bond which performs as well as EPDM-to-EPDM in corner moldings but at significantly reduced costs." Because Santoprene TPV B200 offers much faster cycling times compared with EPDM, processing time savings of 15-30% can be achieved. Good part and tool design can also reduce or eliminate labor intensive post-processing such as trimming flash. In addition, the faster cycling time can reduce or postpone capital investment in new molding machinery and tools because of increased production.
The physical appearance of Santoprene TPV B200 corner moldings offers several advantages compared with those made using EPDM. Unlike EPDM, Santoprene TPV B200 allows textured corner molding or end cap surfaces to accurately match the part aspect and color of the profiles to which they are being adhered. Santoprene TPV B200 corner moldings do not have the "blooming" or aging problems associated with EPDM moldings. The cooler TPV molding process also maintains the quality, appearance and integrity of heat-sensitive flocked or slip-coated surfaces of EPDM profiles which can be damaged in EPDM corner mold presses. Processing corner moldings using Santoprene TPV B200 is easy and efficient. The extruded EPDM or TPV profiles are cut to length and placed in the mold. The Santoprene TPV B200 is then injection molded on top of these profiles. This fast and accurate processing produces fewer errors and any resulting scrap may be recycled. Santoprene TPV B200 is available in 65 Shore A.