Production of three-dimensional moldings from popcorn using innovative molding technology
The present invention relates to moldings made from popcorn, which has been hydrophobicized with a polymer. This allows for production of very light, flexible and water-repellent moldings. In particular, the moldings consist of renewable raw materials. Applications are e.g. for packaging and consumer goods industry.
Today, molded parts (from polymers) like packaging materials are mainly made of polypropylene, polyethylene, polyvinyl chloride and polystyrene. Although they have positive properties such as low density, hydrophobic surfaces, good processability and low thermal conductivity, they also have numerous negative properties. For example, the material is often brittle, has very low chemical resistance and a very low melting temperature. In addition, these plastics are made from finite fossil raw materials, some of which are difficult to reuse. The increase of plastic waste on land and especially in the oceans is becoming an ever greater ecological problem of global significance. Due to these problems, alternative solutions are urgently needed.
Scientists at the Georg-August-University of Göttingen, Germany developed molded parts consisting of popcorn (expanded kernels) and a new molding press process.
The granulated popcorn used for the production of the three-dimensional moldings is coated with a polymer before molding. Due to this coating the popcorn can be stored very well as a pourable granulate before further processing. The new production process uses radio wave technology and is therefore faster and more efficient, thus more cost-effective. The molded parts produced have improved good to excellent properties, such as improved pliability and water-repellent (hydrophobic) properties. In particular, they can be made predominantly from renewable raw materials.
The two techniques, compression molding and automatic molding have been further developed to produce the inventive molded parts. Depending on the application, the surface of the molded parts can then be coated or laminated.
Compression molding (Fig. 1):
Use of automatic molding machines (Fig. 2):
Figure 1: Forming presses (Source: DE102018132738A1)
Various molded parts (prototypes) were successfully manufactured and tested.
German and international patent applications have been filed (applicant: Georg-August-Universität Göttingen Stiftung Öffentlichen Rechts).
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Dr. Stefan Uhle