DuPont Engineering Polymers, Wilmington, Del., is perhaps the first supplier to introduce engineering resins and TPEs based on renewable resources. Its new biopolymer-based products are Sorona polytrimethylene terephthalate (PTT) resin and Hytrel thermoplastic polyester elastomer. While these materials are both polyester-based, DuPont expects to expand its biopolymer offering to nylons too. The key ingredient in both materials is DuPont's Bio-PDO (propanediol), which is derived from corn sugar using a patented bacterial fermentation process. Bio-PDO is a replacement for petrochemical-based PDO and/or butanediol (BDO). Sorona PTT is made by polymerizing Bio-PDO with either terephthalic acid or dimethyl terephthalate. PTT reportedly exhibits properties and molding characteristics similar to PBT but with improved surface appearance and gloss and a glass-transition temperature 15° to 20° C higher than PBT. Potential uses include automotive and electrical/electronic parts. Yazaki, a leading Japanese connector maker, has already demonstrated the viability of Sorona in automotive wire-harness connectors, according to DuPont. Meanwhile, the soft segments of biopolymer-based Hytrel grades will be made with a new polyol derived from Bio-PDO. Preliminary evaluations show a broader use-temperature range and better elastic recovery than current Hytrel materials. Targeted applications include automotive hose and tubing, blow molded CVJ boots, and injection molded airbag doors and energy dampers. Sorona and Hytrel grades made with Bio-PDO will be available in mid-to late 2007.
DuPont Engineering Polymers
350 Bellevue Road P. O. Box 6100
Wilmington, DE 19714-6100
Phone (302) 733-8169 Fax (302) 733-8137