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

TPU for 3D Printing

Title: METHODS OF USING THERMOPLASTIC POLYURETHANES IN FUSED DEPOSITION MODELING AND SYSTEMS AND ARTICLES THEREOF .

 Number/Link: WO2015/109141

Applicant/Assignee: Lubrizol

Publication date: 23-07-2015

Gist”: TPU with specific crystallization temperature and modulus retention can be used for fused deposition modeling

Why it is interesting: Additive manufacturing in all its forms has been a steadily growing trend over the last few years.  Many different materials have been used in these processes, but the use of thermoplastic polyurethane has proven to be difficult because of its low crystallization rate, broad melting range and challenging melt-viscosity control.  According to this application TPU can be used for fused deposition modeling (“3D printing” by extruding molten thermoplastics) when it has a crystallization temperature of about 115°C and retains its shear modulus well with temperature.  Examples of such TPUs have a high harblock content (about 50%) and a molar ratio of chain extender to polyol of 2 to about 4,  and are prepared from 4,4′-MDI, butandiol and 2000 MW PTMEG polyether or butylene-adipate polyester diols.

Fused Deposition Modeling

Fused Deposition Modeling