Prepregs from Glass Fiber and Reactive Polyurethane Powder

Title: PREPREGS AND MOLDINGS PRODUCED THEREFROM

 Number/Link: US2014065911

Applicant/Assignee: Evonik

Publication date: 6-03-2014

Gist”: A reactive polyurethane powder is prepared from a mixture of a  solid polyester polyol and a solid dimerised IPDI and subsequently used to make glass fiber prepregs.

Why it is interesting:  A polyurethane powder is made from (pref.) a mixture of  a solid (at room temperature) polyster polyol and a solid, blocked isocyanate.  The isocyanate is preferably an “internally” blocked IPDI.  Internally blocked meaning that the isocyanate contains uretidinedione groups.  The powder is scattered over a fibrous support and heated to over melting temperature but below curing temperature to make the prepreg.  Prepregs made with PU powder instead of the conventional resins have the advantage of being non-sticky, non-toxic and of having a very high storage stability (45 days in the examples).

Prepreg production with reactive PU powder

Prepreg production with reactive PU powder

Sound Absorbing PU-PA Foams

Title: THERMOFORMABLE RIGID POLYURETHANE-POLYAMIDE FOAM

 Number/Link: US2014/058005

Applicant/Assignee: BASF

Publication date: 27-2-2014

Gist”: Rigid, open-celled and thermoformable polyurethane-polyamide foams are produced using short chain di-acids as both chain extender and blowing agent.

Why it is interesting: The reaction of a carboxylic acid group with an isocyanate group results in a mixed anhydride, which after releasing carbon dioxide forms an amide. Because the reaction is relatively sluggish a  Lewis base catalyst is used, e.g. N-methylimidazole. In this case a rigid foam-forming formulation based on MDI and (pref.) polyether polyols is further reacted with short chain diacids like azelaic- or glutaric acid.  The examples show foam densities of less than 30 kg/m³ without the use of water.  The foams are open celled with high air flow and with a Tg of around 90°C, making them thermoformable.  This type of foams is used as acoustic bonnet- en roofliners in the automotive industry.

Azelaic Acid

Azelaic Acid

Polyurea ‘Nano’-Particles to Improve Properties of Polyurethane Flexible Foams and Elastomers

Title: USE OF POLYUREA NANOPARTICLES AS PERFORMANCE MODIFIERS IN POLYURETHANE MATERIALS

 Number/Link: WO2014/012769

Applicant/Assignee: Huntsman

Publication date: 23-01-2014

Gist”: A dispersion of polyurea particles prepared from 4,4′ MDI, diamine chain extender and a high mole weight monoamine is used to improve mechanical properties of flex foam.

Why it is interesting: Dispersions of polyurea particles with an average diameter of a few hundred nanometer and a Tg>150°C (pref.) can be produced by first reacting a relatively high MW polyether monoamine and a di-isocyanate (optionally dispersed in e.g. polyol) and subsequently adding a diamine chain extender. The dispersion is then used in a flexible foam or elastomer formulation, such that the amount of particles in the material is about 1-5% (w/w). In an example a 2000MW EO/PO monoamine was used together with 4,4′-MDI and a diamine chain extender to produce a particle dispersion in polyol, which was then used in polyurethane formulations. The particles do seem to have a positive effect on mechanical properties, however, the results for flex foam are clouded because of a sharp increase in material density compared to the reference. This density increase may well be due to a cellopening effect as described in WO2007/104623  in which a similar particle dispersion is used.

Polyethermonoamine as used in the invention.

Polyethermonoamine as used in the invention.

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