A new impact modifier from Arkema Inc., Philadelphia, addresses three market needs: boosting low-tempera-ture impact of PC/ABS, improving flow of polycarbonate alone, and doing both economically. New Durastrength 410 is a weatherable, acrylic impact modifier (AIM) designed to provide high efficiency at lower cost than the company’s “Cadillac” product, Durastrength 440. Arkema says D440 is still the highest-performing acrylic impact modifier for PC and PC/PBT, but new D410 proves to be a better toughener for PC/ABS and has a unique processing advantage in PC as well.
“Much recent development has focused on the rubber core of core/shell type impact modifiers,” says Dr. Jason Lyons, Arkema research scientist. “We optimized both the core and shell of Durastrength 410 for PC/ABS.” D410 is a powder, like D440. Pellet forms of both products are in development.
Durastrength 410 is “targeting applications in automotive parts, appliances, business equipment, electrical/electronics, and safety/leisure equipment,” says Connie Lo, commercial development manager. In particular, PC/ABS has faced mounting competition from TPOs for low-temperature impact. The new modifier gives PC/ABS new muscle in cold weather and at lower cost than before. It may also allow processors to use more recycled or regrind material and maintain performance.
TOUGHENER & FLOW ENHANCER
Arkema’s test data (see graphs) show that D410 is slightly less effective than D440 or Arkema’s ClearStrength E920 MBS modifier in toughening PC/ABS at room temperature at a low loading level of 1%. At higher levels, new D410 matches or exceeds the other two. At -20 C, new D410 matches or exceeds D440 and E920 at all loadings, and it significantly outperforms the others at -40 C. D410 also beats a competitive all-acrylic modifer at all loading levels and temperatures. What’s more, D410 significantly increases flow of PC/ABS relative to all the other modifiers tested.
In PC alone, D410 does not match the toughening action of D440 or a competitive acrylic modifier, but it does impart dramatically higher melt flow than either of the others.