Molding Compounds with High Bioplastic Content, Impact Strength, and Heat Resistance Open More Uses for PLA

FDA-Compliant Terraloy™ BP-34001 Substantially Out-Performs Standard PLA and Yields 28 to 30% Shorter Molding Cycles than Previous ‘Enhanced-Performance’ PLA Resins

PAWTUCKET, RI, U.S.A., May 9, 2011: New technology developed by Teknor Apex Company has eliminated a property tradeoff that until now has limited use of polylactic acid (PLA) in injection molded semi-durable and durable applications requiring impact strength and heat stability, as well as in high-end disposable food service items such as cutlery, coffee lids, and containers for microwavable products, it was announced today by the company’s Bioplastics Division.

Shown are test samples of Terraloy™ BP-34001 PLA with enhanced thermal properties (bottom sample in photo) and standard PLA (top sample). At 140 ºC, standard PLA exhibits considerable heat distortion while sample from Terraloy compound is largely unaffected.

Compounding innovations by Teknor Apex have overcome an inverse relationship between heat distortion temperature (HDT) and Izod impact strength in PLA, creating a new series of compounds, Terraloy™ BP-34001, that provide up to two times the HDT and up to six times the impact strength of standard PLA resins. Previous work to enhance PLA performance beyond standard levels had generated resins with either higher HDT or greater impact strength—but not both in the same grade

In comparison with previous enhanced-performance PLA resins, the new Terraloy compounds also exhibit 28 to 30% shorter cycle times in injection molding and incorporate 10 to 30% more renewable resource-based content. Nearly all of the new Terraloy compounds comply with FDA requirements for food-contact applications.

“Terraloy BP-34001 Series compounds dramatically improve the heat and impact resistance of PLA while largely retaining the environmental benefit of this polymer as a bioplastic,” said Edwin Tam, manager of new strategic initiatives. “These innovative formulations promise to expand the applicability of PLA, making possible new uses in higher-heat food service items as well as consumer goods.”

In property tests, a typical grade in the new series, Terraloy BP-34001D, exhibits a heat distortion temperature of 112 ºC and Izod impact strength of 135 J/m. By comparison, approximate values for standard PLA are 65 ºC and 33 J/m. The new compound complies with FDA 21 CFR requirements and has a renewable content of 78%.

The base polymers for Terraloy BP-34001 products are Ingeo® resins supplied by NatureWorks LLC, noted Gregory J. Anderson, Teknor Apex technical manager. “Teknor Apex built upon research by NatureWorks to develop higher-performance PLA compounds,” Anderson said. “By discovering alternative formulations and compounding techniques, we succeeded in eliminating a chronic property tradeoff between heat resistance and impact resistance, while improving processability and reducing the petrochemical content,” Anderson said.

Ingeo® is a registered trademark of NatureWorks LLC. For more information about these PLA resins, visit http://www.natureworksllc.com.

Source: www.teknorapex.com