Dow Automotive Systems has announced a new record-breaking, under-60-second molding cycle time for the VORAFORCE 5300 epoxy resin matrix, with 30-second times coming later this year. The product was initially aimed at high-pressure resin transfer molding (RTM) for making structural parts for high-volume car production, but VORAFORCE 5300 with the shorter under-60-second processing time is aimed at both RTM and wet compression processes, says Peter Cate, global strategic marketing manager for Dow Automotive.
Previously, Dow Automotive’s 90-second commercial matrix had a processing viscosity of 15 millipascal seconds (mPa.s), but that’s now been lowered to 10 mPa.s – four to five times lower than previous competitor’s benchmarks, Cate says. The resin’s lower viscosity means faster infusion with less movement of the fibers, better wet-out and longer infusion times. These enable complete wetting and filling of the large structural consolidated composite parts that automotive OEMs want, which save costs and improve reliability.
“In wet compression, the infusion and flow parts of what goes into total cycle time in an RTM tool are eliminated, and the molding step is really the curing step,” said Cate. “This is important because the press is now doing only what it’s really best at doing: curing resin as fast as possible. With RTM, we can get the process down to less than 60 seconds. But in wet compression, cycle time can go down to 30 seconds, and the tool can run hotter, so the part cures faster.”
For some applications, automotive suppliers also want higher thermal performance than VORAFORCE 5300’s glass transition temperature of 120 C, Cate says, so Dow Automotive is developing two new grades of VORAFORCE: 6300, with a glass transition temperature close to 150 C, and 7100, with a glass transition temperature of about 170 C. These were developed for specific application needs, such as a higher temperature in normal operations or in automotive assembly during the e-coat bake stage. All three grades are designed to work with both RTM and wet compression with need no post-curing.