PHA Plays Role as Multifunctional Additive in PVC

Biopolymer supplier Metabolix, Cambridge, Mass., has amassed further data on how its PHA copolymers can play a role as a multifunctional additive to enhance processing of both flexible and rigid PVC and in broad range of applications. The company’s technical presentation, “Biobased PHA Copolymers as Functional Additives for Polyvinyl Chloride Compound,” at the recent Vinyltec 2015 addressed the latest data.

It was at NPE2015  that company president and CEO Joe Shaulson confirmed that Metabolix was changing focus for its PHA—from commodity to specialty applications, and that it had developed several PHA-based polymer modifiers for processing and performance enhancement of other polymers, including PVC and PLA.

In a recent interview, Max Senechal, v.p. strategy & commercial development at Metabolix, discussed the two key PHA copolymers for PVC addressed in the latest data, stressing the unique miscibility of PHA with PVC: I6002 amorphous grade for more flexible PVC and I6003 semi-crystalline grade for rigid PVC. He also discussed the varied end-use applications, starting with the first two most likely to see swift commercial realization with field testing underway:

• Flooring: a flexible/semi-rigid application whereby I6002 has been shown to serve as both a compatibilizer and an internal lubricant/processing aid. Moreover, at use levels of 3-5%, it has been shown, to promote increased levels of both post-industrial and post-consumer recycle content as well as mineral filler—a big plus in this application.

• Extruded railing in PVC/wood polymer composites: a rigid application whereby I6003 has been shown to act as both a compatibilizer and processing aid. It promotes better dispersion of wood filler and mineral fillers, resulting in improved rigidity and allowing for use of higher levels of these fillers. This, while maintaining torque—versus the increased torque and wear of extruders associated with higher filler levels.

• Roofing membranes: a flexible-to-semi-rigid application where I6002 has been shown to act as a high-molecular-weight secondary plasticizer and process aid. It reportedly enhances PVC permanence especially in installations where low plasticizer migration is required, and oil and grease resistance is needed.

• Extruded wire and cable jacketing: In this flexible PVC application, I6002 has been shown to serve as a processing aid during extrusion to enhance output while achieving a higher quality surface finish.

Other PVC applications being explored included tubing and films.