Evonik Degussa Gmbh

Evonik Operations Gmbh

Sandra Reemers

Uwe Stapperfenne

Emmanouil Spyrou

Friedrich Georg Schmidt

Holger Loesch

Markus Hallack

Guenter Schmitt

Elke Gollan

Christina Cron

Marina-Elena Schmidt

Tobias Gutmann

Stephan Kohlstruk

Eike Langkabel

Heike Heeb

Günter Schmitt

Marina Grammenos

Leif Ickert

Katharina Cielaszyk

Birte Olland

Michael Spittler

Christina Diehl

Michael Kube

Zuhal Tuncay

Provided is a storage-stable polyurethane prepegs and mouldings produced therefrom composed of polyurethane compositions with liquid resin components, preferably liquid polyols. A prepeg contains(A)a fibrous support and (B)a matrix material containing a reactive polyurethane composition. The polyurethane composition contains a mixture of a liquid resin component(b)having a functional group reactive towards an isocyanate and having a glass transition temperature(Tg)or melting point below 25&#xb0; C., with a hydroxyl number of 50 to 2000 mg KOH/gram, and a curing agent(a)comprising a di- or polyisocyanate internally blocked or blocked with a blocking agent. In addition, the polyurethane composition contains 0.6 to NCO equivalents or 0.3 to 1 uretdione group in (a) for each functional group of (b).

Storage-stable polyurethane prepregs and mouldings produced therefrom composed of a polyurethane composition with liquid resin components

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

The invention relates to a process for producing storage-stable polyurethane prepregs and to moldings (composite components) produced therefrom. The prepregs and, respectively, components are produced by mixing (meth)acrylate monomers, (meth)acrylate polymers, hydroxy-functionalized (meth)acrylate monomers and/or hydroxy-functionalized (meth)acrylate polymers with uretdione materials. Photoinitiators can also optionally be added. This mixture or solution is applied by known processes to fiber material, e.g. carbon fibers, glass fibers or polymer fibers, and is polymerized with the aid of radiation or of plasma methods. Polymerization, e.g. at room temperature or at up to 80&#xb0; C., gives thermoplastics or thermoplastic prepregs, and these can subsequently also be subjected to forming processes. The hydroxy-functionalized (meth)acrylate constituents can then be crosslinked with the uretdiones already present within the system, by use of elevated temperature. It is thus possible to produce dimensionally stable thermosets or dimensionally stable crosslinked composite components.

Composite semifinished products and mouldings produced therefrom and directly produced mouldings based on hydroxy-functionalized (meth)acrylates and uretdiones which are crosslinked by means of radiation to give thermosets

A method of producing a fiber composite component part has the following steps: a) providing two or more metal sheets each comprising an aluminum material; b) providing at least one textile fabric; c) providing an anhydrous mixture having one or more than one hardener having a uretdione having an NCO functionality of not less than two, one or more than one binder having hydroxyl groups to an OH functionality of three to six, and one or more than one cobinder having oxirane groups; d) coating the textile fabric with the anhydrous mixture, to obtain a mixture-coated fabric; e) applying energy to the mixture-coated fabric for the purpose of performing a first crosslinking reaction to react hardener, binder and cobinder to form a thermoplastic polymer adhering to the textile fabric; f) hot pressing the metal sheets and the textile fabric together with the thermoplastic polymer adhering thereto into a sandwich such that the thermoplastic polymer joins the metal sheets together while enclosing the textile fabric; g) forming the sandwich into a shaped article; and h) heat treating the shaped article to obtain the fiber composite component part, wherein the thermoplastic polymer undergoes a second crosslinking reaction to convert into a thermoset polymer.

Production of fibre composite component part based on aluminium and polyurethane

A method of producing a fiber composite component part, contains the following steps: a) providing two or more steel sheets; b) providing at least one textile fabric; c) providing an anhydrous mixture having one or more than one hardener containing a uretdione having an NCO functionality of not less than two, one or more than one binder having hydroxyl groups to an OH functionality of three to six, and one or more than one cobinder having oxirane groups; d) coating the textile fabric with the mixture; e) applying energy to the mixture-coated fabric for the purpose of performing a first crosslinking reaction to react hardener, binder and cobinder to form a thermoplastic polymer adhering to the textile fabric; f) hot pressing the steel sheets and the textile fabric together with the thermoplastic polymer adhering thereto into a sandwich such that the thermoplastic polymer joins the steel sheets together while enclosing the textile fabric; g) forming the sandwich into a shaped article; h) heat treating the shaped article to obtain the fiber composite component part, wherein the thermoplastic polymer undergoes a second crosslinking reaction to convert into a thermoset polymer.

Production of fibre composite component part based on steel and polyurethane

Provided is a prepreg composed of a fibrous substrate impregnated with a reactive or highly reactive polymer composition as a matrix material. The reactive or highly reactive polymer composition contains a (meth)acrylate-based resin comprising at least one of a hydroxyl group, an amine group, a thiol group, an initiator and/or accelerator, and a di- or polyisocyanate which has been internally capped, capped with a capping agent, or a combination thereof. The (meth)acrylate-based resin contains from 20% by weight to 70% by weight of at least one (meth)acrylate monomer and from 1% by weight to 50% by weight of at least one prepolymer.

Composite semifinished products, molded parts produced therefrom, and molded parts produced directly based on hydroxy-functionalized (meth)acrylates, which are cross-linked by means of uretdiones in a thermosetting manner

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Münster, Germany

Sandra Reemers