Reactive TPU for AM

Patent Title: REACTIVE THERMOPLASTIC POLYURETHANE BASED ON BLOCKED ISOCYANATES

 Number/Link: WO2018/149977

Applicant/Assignee:  BASF

Publication date: 23 August 2018

Gist”: Low molecular weight TPU with blocked isocyanate groups is useful for 3D printing

Why it is interesting: The invention is related to relatively low MW ( up to 40,000Da) thermoplastic polyurethanes with thermolabile end groups and a melting point of about 100ºC (pref).  The TPU has a low melt viscosity and after de-blocking (at pref. about 150ºC) the isocyanate groups can react with chain extender present, resulting in increased MW and related properties. The TPU can be prepared by partially blocking diisocyanates (with e.g. caprolactam) and then reacting in one shot or prepolymer system with polyols and chain extenders. In powder form the TPUs are said to be useful in additive manufacturing (AM) processes.

caprolactam

Caprolactam

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