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Another new medical-grade acrylic copolymer is Plexiglas CR (chemical resistant) from Arkema Inc., Philadelphia. It is said to show outstanding resistance to ESCR from oncology drugs and other lipid solutions, as well as from isopropyl alcohol disinfectants. Lipid resistance reportedly is much better than other clear medical-grade plastics, including lipid-resistant PC. Plexiglas CR also boasts excellent clarity (better than PC), flow, and gamma sterilization resistance. It comes in two versions, a premium CR50 grade with maximum lipid and chemical resistance, and a lower-cost CR30 grade with somewhat higher stiffness, strength, impact, and flow.
Arkema also announced that it will be coming out with Plexiglas Rnew by midyear, a renewably sourced resin based on a blend of PMMA and PLA. Biobased content will range from under 20% to as high as 50%. Impact grades of Plexiglas Rnew are also in development.
A third new clear, rigid resin at MD&M was Tritan MX811 proprietary copolyester from Eastman Chemical Co., Kingsport, Tenn. This, the fourth medical grade of Tritan, is an injection molding grade aimed specifically at renal-care device housings. It has higher heat resistance than previous grades, with a glass-transition temperature (Tg) of 118 C vs. 110 C for other Tritan materials. Higher Tg allows for faster cycles in molding. Tritan has ESCR resistance to blood, lipids, isopropyl alcohol, and bonding solvents. It also boasts good toughness, high clarity, and color stability after radiation sterilization.