NEUSS, GERMANY—The profile extrusion industry recently began employing soft thermoplastic olefins for rigid window-seal components and refrigerator-seal applications, according to TPO producer Montell Polyolefins.
Montell is developing elastomeric and cross-linked modified products to provide TPOs with greater softness, better strength and heat resistance and improved density. Those products also will be commercialized for use in the profile extrusion sector shortly, said Marc Bormans, head of building and construction applications at Montell's research and development business support unit at Ottignies, Belgium.
TPOs are becoming an important part of the larger thermoplastic elastomer market, he said at Profiles '99 in Neuss. In 1997, TPO consumption in Europe was estimated at 218 million pounds, representing 26 percent of the region's TPE market.
Bormans said Montell's Catalloy process can make very soft TPOs by blending polypropylene with high levels of rubber — as much as 70 percent — in the polymerization reactor. The material, sold under the trade name Adflex, has different grades with varying properties and performance characteristics.
The company markets the Q100F grade for profile extrusion applications. It can be extruded on conventional equipment, including PVC extrusion lines, is easy to process at conditions similar to PP, has good adhesion to other polyolefins and retains mechanical properties at a range of temperatures, Bormans said.
To improve strength, heat resistance and recovery after deformation, polymers are cross-linked via chemicals, hydrogen bonding or ionics, he said.
``Cross-linked blends meet the softness and elastic recovery requirements for refrigerator- and window-seal applications,'' Bormans said.
To improve density, some applications require foamed TPOs, he added.