Machine Design

Scratch-Resistant Copolymers

A family of PC-copolymers has five times the surface hardness of conventional PC (polycarbonate).

A pencil hardness (1 kgf) standard test gave the Lexan DMX PC-copolymers an H rating and the PC a much lower 2B rating. A hardness in the H range will let designers eliminate hard coats on keypads, housings, and other wear parts on mobile phones, computers, and digital cameras that take a beating from constant handling. The PCcopolymer's surface hardness also surpasses painted acrylonitrile butadiene styrene (ABS) and PC/ABS that both received a mid-range F pencil hardness rating. Further, when hardcoated with silicone or acrylic the Lexan DMX grade's pencil hardness increases to 3H.

GE Plastics, One Plastics Ave., Pittsfield, MA 01201, (800) 752-7842,

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