[News] New masterbatches add color to compostable plastics

By MPW Staff
Published: June 28th, 2010

New masterbatches from Clariant (Muttenz, Switzerland) have been formulated for use in biopolymer applications requiring compliance with European and U.S. standards governing compostability and ecotoxicity, including the harmonized EN 13432:2000 standard. Because they incorporate conventional (non-natural) additives and pigments, the new masterbatches are said by the supplier to be more economical and more process- and light-stable than "natural" products, and they bring a broader choice of colors and additive functionality to bioplastic products and packaging.

More than 80 pigments are expected to be available, which will allow a large number color masterbatches to be offered under the Clariant Renol-compostable brand name. CESA-compostable additive masterbatches will include UV-stabilizer and antioxidant packages, with more additives currently pending review.

Testing of the ingredients in the masterbatches was completed in the independent laboratories of OWS nv (Gent, Belgium). There, it was determined the materials comply with the EN 13432:2000 standard for heavy-metal content and plant-toxicity.

Clariant also is in the final stages of product evaluation for the highly desirable "OK compost" certification issued by AIB Vinçotte International (Vilvoorde, Belgium). The compostable products made at the Clariant facility in Sant Andreu de la Barca, Spain (near Barcelona) are expected to be certified in July. A plant in Pogliano Milanese, Italy, which already holds an "OK compost" certificate for a black masterbatch used mainly in agricultural film, will soon obtain the Vinçotte approval stamp for the whole range of new eco-friendly masterbatches it manufactures.

Vinçotte is an independent testing organization that has developed certification programs for compostable and bio-based products.

Any product featuring the "OK compost" logo can be assumed to comply with the requirements of the EU Packaging Directive (94/62/EEC), which seeks to limit packaging waste. The "OK compost" certificate guarantees that only colorants and additives that pass testing for ecotoxicity are added to the biopolymer carrier resin.

All-natural color and additive masterbatches made entirely from renewable resources have been available for a few years, but color choices are limited and light and process stability can be an issue in certain applications. These new compostable additives and masterbatches are said to overcome those limitations without changing the compostability of products made of the bio-based resins.