According to Sabic Innovative Plastics (Pittsfield, MA), the supplier of the materials, the new Noryl GTX conductive blends, with their lower CTE, offer plastics processors a thermoplastic with significantly greater dimensional stability for larger automotive body panels and fenders, among other applications. Lower CTE means parts formed form these new conductive blends of polyamide (PA) and modified polyphenylene ether (PPE) have improved gap and flush management, giving automotive designers the freedom to include more plastic body panels - with their increased design potential versus metal - without worrying as much about plastics' shrinkage after online painting systems.
The supplier's V. Umamaheswaran, director of products and marketing for its automotive plastics' business unit, pulled no punches on the material's potential. "This is a breakthrough in automotive design that promises to significantly expand the use of thermoplastic body panels," he said.
The supplier will not disclose the specifics as to how it achieved the lower CTE except to say it has utilized "new technology." The improved thermal expansion properties do not come at any loss of mechanical ones, it adds. Noryl GTX 98 series of resins feature 20% less moisture uptake and post-heat shrinkage than previous grades. Another aesthetic benefit is the perception of robustness in a plastic part, resulting from a 50% improvement in stiffness over previous Noryl GTX grades.
In online painting, Noryl GTX 98 resin series delivers a 10°C improvement in heat tolerance, making them compatible for higher-temperature online painting.
To meet different CTE requirements (related to part length), the supplier will offer up to four different variations of the new blends; currently, Noryl GTX 987 and 989 grades are available.