Evonik Degussa Gmbh

Tobias Gutmann

Sandra Reemers

Christina Cron

Uwe Stapperfenne

Marina-Elena Schmidt

Leif Ickert

Christina Diehl

The invention relates to a process for producing a prepreg based on polyurethane, which is notable for high storage stability at room temperature, a two-stage reaction mechanism, and adjustable adhesion on metal surfaces. It is based on the problem of making the surface tack of the prepregs controllable during processing. The solution is to assemble the PU mixture from which the matrix originates at a later stage such that the glass transition temperature of the thermoplastic polymer is above 30&#xb0; C. For this purpose, the invention proposes two basically independent but certainly synergistic measures, namely:

Polyurethane prepregs with controllable tack

The invention relates to a hybrid component part comprising a local stiffening made of a two-stage-crosslinked polyurethane-based fiber composite material, more particularly to the production of such a hybrid component part. Said invention has for its object to specify a technology which makes it possible in cost-effective fashion to effect local stiffening of metal parts with a fiber composite material in order thus to obtain a hybrid component part. It is a fundamental concept of the process according to the present invention to use a particular polyurethane formulation which in a first crosslinking reaction can be converted into a thermoplastic polymer and later in a second crosslinking reaction is fully crosslinked to afford a thermoset matrix material. The thermoplastic polymer is characterized by a good adhesion to metal surfaces. The metal can be subjected to further forming with the attached thermoplastic material. The polyurethane is subsequently thermosettingly cured and achieves its final stiffness.

Hybrid component part comprising a local stiffening composed of a two-stage-crosslinked polyurethane-based fibre composite material

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Dorsten, Germany

Tobias Gutmann