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"These methods are much more effective and advanced than common features like dewpoint control and temperature setback. Moisture Manager and OverDry Protection are both designed to ensure that the dryer automatically responds to changes in resin moisture and ambient conditions that can lead to improperly dried resins. They have features that eliminate the possibility of overdrying nylons and other sensitive engineered resins. Plus, the technology controls the drying temperature to limit or eliminate the possibility of discolor- ation or polymer breakdown in thermally or visually sensitive resins like PC, PET, ABS, and other translucent and colored resins." Novatec's Moisture Manager uses valves in the dryer and a dewpoint measurement out of the drying hopper to determine if moisture is being pulled from the resin, or if the resin is already dried to the appropriate moisture level. If the resin is already dry, the blower loop will exclude the desiccant and recirculate and heat without using dry air at -40 F/C dewpoint. If, however, the moisture monitor in the hopper outlet senses that the resin requires An increase among molders in running highly tailored nylons— some for the first time—has encouraged one machine builder to develop features aimed at ensuring these mate- rials are dried properly. Novatec Inc., Baltimore (novatec.com), will debut these technologies May 7-11 in Orlando, Fla. at NPE 2018. "Over the past few years, we've seen hundreds of specialty nylons developed for a range of markets that include automotive—where lightweighting is the driver—medical, packaging and more," remarks Mark Haynie, Novatec's dryer product manager. "And as the business of molding commodity resins has continued to move offshore, we've seen quite a few molders taking on projects running nylons and other thermally or visually sensitive resins like PBT, PETG, and others for the first time." What's more, adds Haynie, these molders are typically using press-side dryers—more typically associated with drying commodity materials— to dry these materials. Drying nylon can be tricky business, Haynie points out. Most engineering resins require drying to 100 ppm. Nylon drying specifications, on the other hand, are roughly 500-800 ppm. Molders not accustomed to these parameters tend to overdry the material, which invariably will make the part brittle and fail. "In some cases, nylon straight out of the gaylord does not have to be dried at all," states Haynie. "But still, if the molder's procedures say the material must be dried, that's what they will do." As a result, Novatec has taken two technologies established in central drying and adapted them to its line of NovaWheel portable dryers: Moisture Manager and OverDry Protection. Says Haynie, By Jim Callari Editorial Director Technology Takes Aim At Drying Specialized Resins Novatec develops new at-the-press drying solutions for molders tackling highly tailored nylons and other specialty materials. Hopper outlet temperature starts at 180 F and steps down to 150 F Hopper inlet temperature starts at 250 F and steps down to 220 F 180 F 17 0 F 160 F 155 F 150 F 2 50 F 2 40 F 230 F 22 5 F 220 F Once the OverDry Protection feature is turned on, the dryer will automatically adjust the drying setpoint parameters to maintain the correct drying temperature based on an algorithm in the control program. Side view of Nitrogen NovaDrier shows the air-drying membrane replaced with a membrane that both dries the air and separates nitrogen from compressed air. QUESTIONS ABOUT DRYING? Visit the Resin Drying Zone. Upper- and lower-loop heaters Nitrogen membrane 18 FEBRUARY 2018 Plastics Technology PTonline.com D R Y I N G Close -Up On Technolog y