Firms Collaborate on 'Sustainable' HDPE Pharma Bottle

A new HDPE pharmaceutical bottle that promotes sustainability through lightweighting and production efficiency resulted from a collaboration between Milliken Chemical, Spartanburg, S.C., a leader in nucleation and clarification technology; Jarden Plastic Solutions, Greer, S.C., a high-volume, precision injection molder of medical, consumer and high-end industrial products; and Italian compression molding equipment supplier SACMI (U.S. office in Des Moines, Iowa).

Milliken’s proprietary UltraGuard advanced customizable additive masterbatch technology is key to this project. Incorporated in HDPE to create a passive barrier, the technology reportedly alters the resin’s crystal orientation to create a tortuous path that inhibits passage of moisture and oxygen. In effect, a permeant molecule must move through a maze of crystals that are linear and encircle the side walls of the bottle—a process that slows down permeation significantly. According to Milliken, the technology can increase the barrier properties of HDPE by 20-to-60%, leading to significant lightweighting opportunities, depending on the bottles’ specific geometry and the resin design. (Without the barrier additive, HDPE will typically form large, spherulitic crystals that do little to inhibit the passage of oxygen and moisture.)

Also key to this project is SACMI’s new, proprietary high-volume, rotary compression blow forming (CBF) machine, highlighted at NPE2018. It extrudes “hockey-puck” blanks that are sliced off and placed in compression molds to produce preforms, which are then blown into finished bottles. CBF produces a precision-molded neck, as does injection-blow, but without any gate mark on the bottle. Also, the bottles have greatly reduced melt stresses and more uniform weights between cavities, while the system offers substantial energy savings. The combination of Milliken’s barrier masterbatch and CBF equipment, allowed Jarden to produce the new thin-wall bottles—which are reportedly strong and light and use less energy to manufacture and generate less scrap.

Custom formulated for this application, UltraGuard has potential as a candidate for any PE application that requires barrier including, caps and closures, film applications (cereal bags, cracker bags), beverage bottles (e.g., nutritional drinks), nutraceuticals (probiotics, vitamins), and other types of pharmaceutical containers.