WEB EXCLUSIVE: Last year, Kuraha PGA LLC, began commercial production of its new Kuredux PGA (polyglycolic acid) high-barrier, biodegradable polymer at a plant in Belle, W.Va. The resin is marketed by Kureha America Inc., N.Y.C. The new plant is expected to produce 8.8 million lb/yr of this clear, semicrystalline, aliphatic polyester. (Lower-molecular-weight versions have been used for years in resorbable sutures and surgical implants.) Kuredux is fully compostable. It is said to be easily processed into oriented films and bottles, the major target being soft drinks and beer. When used as the inner layer in multi-layer PET bottles, the bottle reportedly can be recycled using standard PET recycling processes. It is easily dissolved in the alkaline wash-water stages of PET recycling, ensuring complete separation of PGA from PET. PGA can also be combined with PLA or other renewably sourced polymers to make up for their limited properties.
PGA’s claim to fame is its very high barrier and mechanical properties. Oxygen and moisture barrier far exceed those of other barrier resins, including EVOH, MXD6 nylon, and PVDC. PGA also has superior barrier to aromas, flavors, and organic solvents. It also boasts tensile strength and modulus that far exceed those of PET, EVOH, or nylon 6. And unreinforced PGA has higher HDT than PET, MXD6, or polycarbonate. When only 2% by weight of Kuredux is used in a multi-layer PET bottle, total bottle weight can be reduced by up to 35% (despite PGA’s 10% to 12% higher density than PET) with no loss of shelf-life performance, according to Kureha. Three grades of Kuredux are currently available—a basic grade and two grades with higher hydrolysis resistance, one aimed particularly at bottles.
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