Biodegradable polymers, for a long time regarded more as a dream than a practical proposition, have begun attracting a considerable amount of interest. This year's conference on biodegradable materials at the SKZ (Süddeutsches Kunststoff-Zentrum, Frankfurter Str. 15-17, D-97082 Würzburg) on February 11 and 12 in Würzburg was attended by 210 delegates, almost twice the number of previous years. Innovative "biopolymer" products have now begun arriving on the market. One of the major reasons for this sudden leap in interest is certainly the recent initiative made by the food group Danone's German subsidiary Danone Deutschland GmbH (Heinrich-Wieland-Str. 170, D-81735 Munich). As reported in Plasteurope.com No. 23, 1997, Danone in early January 1998 began selling its premium yogurt product "Jahreszeit" in cups made of a polylactic acid (PLA) material produced by Cargill Dow Polymers LLC. In Würzburg, Rainer Schlicht, Danone's European development manager, reported in detail on the introduction of the so-called "Öko cup" and announced that a decision could be made by July 1998 on whether to also convert one of the larger Danone products to PLA packaging.

Marcel Dartree of Cargill Dow Polymers LLC talked about the broad scope of application for polylactic acids. Another PLA material is "Lacea" from Mitsui Chemical Inc. (2-3-6 Kasumigaseki Chiyoda-ku, JP-100 Tokyo), and a paper presented by T. Kuroki dealt with its processing properties. Other materials based on renewable raw materials presented in Würzburg include the bacteria-fermented copolymer "Biopol" from Monsanto, which Detlev Schack discussed in his paper. The product is used, for example, in the compostable composite cup "Polarcup Natur" from Polarcup GmbH (D-56859 Alf / Mosel). Dr. Catia Bastioli of Novamont Spa (Via Fauser 8, I-28100 Novara) spoke on the various classes of "Mater-Bi", a starch-based material

In addition to biodegradable materials based on renewable raw materials, there are also a number of petrochemical-based products. This is not a contradiction in terms as biodegradability is not a question of origin, but depends solely on the molecular structure of the polymer. Of course, fossil resources can be saved only if renewable raw materials are used. Nevertheless, some manufacturers are going for the petrochemical base. Examples of products obtained not from renewable raw materials but from fossil raw materials include the polyester amides "BAK 1095" and "BAK 2195" from Bayer AG (HQ: D-51368 Leverkusen). Dr. Ralf Timmermann promised to present some BAK applications at the conference for K '98.

A central problem which still accompanies biodegradable materials was analysed by Dr. Harald Käb , who pointed out that neither experts from the plastics processing industry nor consumers usually are up to date on the subject. This, he said, complicates dvelopment on two fronts. While plastics processing knowhow is essential to make full use of the development potential of biodegradable materials, well-informed consumers with a positive attitude to the products also are needed to ensure a promising future. "How can the public be persuaded to buy an environmentally friendly product made by an environmentally friendly process if they know nothing about it?" Käb asked. He sought to encourage plastics processors, as manufacturers and sellers of biopolymers, to launch their own public relations initiative rather than leave everything to the renewable materials lobby.