Zelfo - An engineering material fully based on renewable resources

The development of Zelfo was based on a review on technologies for the production of "papier mâche" in the second half of the 19^th century. However, in contrast to "papier mâche" Zelfo does not contain any additional bonding agent. Potential raw materials for the production of Zelfo include various plants and wastes with a high cellulose content (e.g., hemp, flax, waste paper). The first production step is a refining process, in which the raw materials are simultaneously hackled and ground and mixed with water. The result of this process is a microfiberpulp with a solid content of 1 to 15 m%, which is subsequently predried, cast or molded into a final shape and dried. Due to the possible variations in raw materials and in the production process, properties of Zelfo can be varied over a certain range. For example, values for density from 0.5 to 1.5 g/cm³, for tensile modulus from 1500 to 6550 MPa and for tensile strength from 7 to 55 MPa can be achieved. Thus, Zelfo is likely to compete with both conventional plastics and chipboard for certain applications.