Production of three-dimensional moldings from water-repellent popcorn

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.

Challenge

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.

Our Solution

Scientists at the Georg-August-University of Göttingen, Germany developed molded parts consisting of popcorn (expanded grains) and a small amount of polymer. Due to the polymer content, these moldings have improved and excellent properties such as improved flexibility and water-repellent (hydrophobic) properties. In particular, they can be produced predominantly from renewable raw materials. 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.

Formpressen (Bild 1):

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):
The popcorn surrounded by polymer is placed in a cavity which is heated under pressure and conductive heat transfer. The pressure gives the molding compound the shape specified by the mold.

Use of automatic molding machines (Fig. 2):
This technique uses automatic molding machines, which allow higher pressures and/or temperatures. The first process step consists of pneumatically pre-compressing the molding compound (i.e. the polymer-coated popcorn) and filling it in the cavity of the mold. Temperature and pressure are used to heat the molding compound. After the popcorn particles have bonded together, the last process step is to remove the molded part from the mold.

 

Bild 1: Formpressen (Quelle: DE102018132738.2)

Bild 2: Verwendung von Formteilautomaten (Quelle: DE102018132738.2)

Advantages

  • Molded parts made from renewable raw materials
  • Production of hydrophobic, very light and flexible moldings
  • Very good storability and pourability of the renewable granulate

Applications

  • Packaging materials (e.g. cool boxes, protective packaging for electrical appliances);
  • automotive parts (e.g. headrests, sun visors, child seat shells, insulating mats);
  • insulating materials (e.g. electrical appliances);
  • sports equipment (e.g. yoga rolls, bolsters);
  • toys (e.g. dice, boards for board games, puzzles);
  • Household articles (e.g. spice jars, dishes, baskets, picture frames)

Development Status

Various molded parts (prototypes) were successfully manufactured and tested.

Patent Status

An international patent application has been filed (applicant: Georg-August-Universität Göttingen Stiftung Öffentlichen Rechts).

Contact

Dr. Stefan Uhle
Patent Manager Life Science
E-Mail: suhle(at)sciencebridge.de
Tel: +49 551 30724 154
Referenz: BioC-2138-SUG

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