Newly available cast sheet and thermoforming grades of Mirel biobased polymers open up a new range of applications in containers and other formed parts where renewable content and biodegradability are desired. These bioplastics are FDA food compliant and offer a property balance similar to HIPS and processing similar to HIPS or PP.
Mirel sheet has been used in the new bottomless plantable pot manufactured for Ball Horticultural Company, West Chicago, Ill., and available at Lowe’s home-improvement centers. Made of rolled sheet with a welded seam, Ball’s SoilWrap plantable pot replaces PS or PP containers that hold a new plant in place when they are planted into the earth. The PHA pot biodegrades in the soil.
Mirel bioplastics are semi-crystalline thermoplastic polyesters derived from microbial fermentation of plant sugars, principally from corn. Mirel is a type of PHA (polyhydroxyalkanoate), specifically a proprietary blend of PHB (polyhydroxybutyrate) copolymers, additives, and mineral fillers. It is produced at a 110-million-lb/yr plant in Clinton, Iowa, which opened in 2009.
Mirel PHA is BPI-certified to meet U.S. standards for compostable plastics according to ASTM D6400. It also meets the ASTM D7081 standard for non-floating biodegradable plastics in a marine environment. Mirel has been Vinçotte-certified in Europe for biodegradability in natural freshwater environments, natural soil environments, industrial composting, and home composting.
Telles’ Mirel 4000 series is for sheet applications, while its Mirel 3000 series is designed for thermoforming. Both have been commercially available since October 2010. Telles offers each series in a “P” version for general-purpose applications and an “F” version for food contact.
The Mirel 3000 series (P3001, F3002) are high-melt-strength grades designed for low heat sag in thermoforming. They are suitable for a wide range of medium-draw foodservice and packaging applications, including hot and cold cups, cup lids, yogurt containers, tubs, trays, and single-serve food packaging. Applesauce containers, temporary foodservice trays, coffee cups and lids, pipette trays, and pill boxes are already being considered.