Living hinge caps using 100% rPP: PureCycle and StackTeck conduct successful trials
Last update on Jun 15, 2026
Living hinge caps – among the most mechanically demanding applications in injection molding – can now be produced using up to 100% post-consumer recycled polypropylene, according to results published by PureCycle Technologies and StackTeck Systems.
Withstand hundreds of flex cycles without failure
The collaboration addresses a persistent constraint in sustainable packaging development: living hinges require a polymer capable of withstanding hundreds of flex cycles without failure, a threshold that has historically excluded recycled resins and confined the application to virgin polypropylene.
Caps produced with PureFive Ultra™ and PureFive Choice™ resins passed customer-related flex cycle testing, with dimensional tolerances matching those of equivalent caps made from virgin resin. This unlocks a new category of sustainable packaging applications for brand owners seeking to incorporate recycled content without sacrificing functionality.
“At StackTeck, we are constantly working to advance what’s possible with injection molded plastics and sustainability is increasingly at the center of that work,” said John Rego, senior market development specialist. “Partnering with PureCycle on this living hinge cap is a testament to what industry collaboration can accomplish. PureFive® resin processed beautifully in our tooling and the final part performance speaks for itself. We look forward to supporting converters and brand owners who want to bring this kind of sustainable innovation to market at scale.”
Application in food, beverage, personal care and household products
StackTeck’s precision tooling and deep expertise in caps and closures mold design were critical to optimizing processing conditions and part geometry for the recycled resin. According to the companies, the resulting cap successfully passed all required flex cycle testing, confirming its readiness for commercial packaging applications including food, beverage, personal care and household products.
“This achievement with StackTeck marks a significant step forward in demonstrating the versatility and performance of our PureFive® resin,” said Pete Dias, PureCycle’s senior director of Market, Application and Product Development. “Living hinges represent one of the toughest tests for any polypropylene and the fact that we’ve proven our recycled resin is up to the challenge opens the door to a whole new set of packaging applications for our customers. We are proud to work alongside StackTeck’s world-class team to keep pushing the boundaries of what recycled content can achieve.”
Proprietary recycling process removes color, odor and other impurities
PureCycle reports that its physical, dissolution recycling process transforms post-consumer polypropylene into PureFive® resin by removing color, odor, additives and other impurities from the plastic. The resin performs similarly to virgin polypropylene and meets FDA standards for food-contact applications to enable the seamless integration into existing manufacturing processes. PureFive® resin is also APR Certified for PCR Content, a requirement for many impending regulations across the United States.
Brand owners and converters interested in incorporating PureFive® resin into living hinge or closures applications can contact PureCycle to discuss trial opportunities.
You can also review recycled polypropylene resin grades and compare performance parameters in the Master Catalog of Plastics.