ADDITIVES: A New Toolkit for Modifying PLA

New additives boost performance, processability, and appearance of biopolymer.

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A rich crop of new additives have arrived for boosting performance, processability, and appearance of PLA biopolymer.

•PolyOne Corp., Cleveland, is offering new OnCap BIO L masterbatches containing a new-generation acrylic impact modifier for PLA from Dow Plastics Additives, Philadelphia. Dow’s new Paraloid BPM-520 toughens opaque injection molded PLA with minimal effect on HDT or stiffness, according to Dow. It reportedly is effective at both room and sub-zero temperatures, is FDA food-contact compliant, and also toughens PLA/PC alloys.

•Plastics Color Corp. (PCC), Calumet City, Ill., introduced SoluPLAs masterbatches for PLA. These include impact modifiers for clear or opaque PLA (which also aid slitting of extruded sheet), a mold release, denesters for unstacking deep-draw parts, antistats, UV absorbers, and blue toners to mask yellowing.

•Terraloy 9000 Series clear impact-modifier masterbatches fromTeknor Apex Co., Bioplastics Div., Pawtucket, R.I., contain PLA carrier and Biostrength toughener from Arkema Inc., King of Prussia, Pa. It meets FDA food-contact requirements.

•Rhein Chemie Corp., Chardon, Ohio (a unit of Lanxess Corp., Pittsburgh), has come out with BioAdimide additives for PLA, intended to make it suitable for durable products. BioAdimide 500 XT is a chain extender that raises the melt viscosity of PLA 20-30% to aid extrusion and blow molding. BioAdimide 100 improves the hydrolytic stability of PLA by up to seven times, helping to increase the service life of PLA products.

•The Swiss parent of Sukano Polymers Corp., Duncan, S.C., is offering “bioconcentrates” for PLA. These masterbatches use a biopolymer carrier for slip/antiblock (to aid denesting), nucleating agents (to enhance crystallinity for higher heat resistance), UV stabilizers, impact modifier (for clear products), and colorants/toners for clear or opaque formulations.

•Though not a new product, new benefits have been discovered for Biomax Strong 120 impact modifier from DuPont Packaging & Industrial Polymers, Wilmington, Del. Besides toughening PLA, the additive also reduces crinkly film noise in PLA films, DuPont reports. It also reduces power consumption and increases thermal stability during extrusion. The result can be 21% greater extruder energy efficiency with just 2% of the additive, and the added thermal stability facilitates scrap reprocessing and could help expand use of PLA in extrusion coating, which uses relatively high melt temperatures.