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

TPUs from Block Polyester Polyols

Patent Title: THERMOPLASTIC POLYURETHANE HAVING HIGH TEAR PROPAGATION STRENGTH  & PROCESS FOR PRODUCING TRANSPARENT HARD THERMOPLASTIC POLYURETHANES

 Number/Link: WO2018/115460  WO2018/115468

Applicant/Assignee:  BASF

Publication date: 28 June 2018

Gist”:  Polyester polyols containing a “hard block” of polyethyleneterephthalate are used in the preparation of TPU 

Why it is interesting: According to this invention thermoplastic polyurethanes with a high hardness at a relatively low hardblock level (<75%), or a high tear strength at relatively low Tg (<5°C) can be prepared from a polyester polyol that is a block copolymer containing 10-50% of an aromatic polyester block, the rest being aliphatic polyester. In the examples diols are prepared from PET together with adipic acid and BDO or DEG. The diols are reacted with MDI or HDI and a chain extender like BDO or HDO.

PET

Poly(ethyeleneterephthalate)

Fiber Reinforced TPU Composites

Patent Title: THERMOPLASTIC POLYURETHANE MATRIX RESIN

 Number/Link: WO 2018/104145

Applicant/Assignee:  Henkel

Publication date: 14 June 2018

Gist”: TPU based on a vicinal alkane diol together with an alkoxylated aromatic diol can be used as matrix material in a fiber composite

Why it is interesting: According to this invention a thermoplastic polyurethane with a high Tg (pref. >80°C) and a high stiffness (>1GPa) can be prepared from a short chain, sterically hindered, vicinal diol (e.g. 1,2-propanediol or 2,3-butanediol), an alkoxylated aromatic diol (e.g. alkoxylated bisphenol A or F) and an aromatic diisocyanate (e.g. 4,4’MDI) pref. mixed with some high functionality isocyanate (e.g. polymeric MDI) to control branching an molecular weight. The TPU composition can be used to make a fiber reinforced composite in an RTM-type process. The cured thermoplastic matrix has high mechanical properties but still allows for post-cure modification of the moulded part.

EtoxBisF

Ethoxylated Bisphenol F

Foamed and Coloured TPU Pellets

Patent Title: PROCESS FOR DYEING AND FOAMING THERMOPLASTIC POLYURETHANE

 Number/Link: WO2018/091446

Applicant/Assignee:  Huntsman

Publication date: 24 May 2018

Gist”: TPU pellets are both coloured and foamed using supercritical carbon dioxide.

Why it is interesting: According to this invention, coloured and foamed thermoplastic polyurethanes can be prepared by saturating TPU pellets (in an autoclave under controlled temperature and pressure) with supercritical CO2 together with a dye.  After impregnation is complete the pressure is dropped at a temperature between the TPU’s Tg and Tm, resulting in expanded TPU pellets or ‘beads’.  The process has the advantage of allowing for the use of a wider range of dyes as compared to conventional pigment-based colours. The TPU beads are said to be especially useful for the production of shoe-soles colour-matched with textiles.

azo compound

Typical azo compound used in dispersion dyes

Oxidation-Proof TPU

Patent Title: POLYURETHANE, METHOD OF PREPARATION, AND ARTICLE COMPRISING THE POLYURETHANE

 Number/Link:  WO2018/057488

Applicant/Assignee:  THE UNIVERSITY OF MASSACHUSETTS

Publication date:  29 March 2018

Gist”:  TPU based on hydrogenated diene diols

Why it is interesting: TPUs based on polyether- or polydiene-diols are prone to oxidative degradation and therefore less useful for e.g. medical applications.  According to this invention, oxidation-stable TPUs can be prepared from hydrogenated polydiene diols with an Mn of 500 to 2000, combined with 5-25% (w/w) polyether diols, chain extender and diisocyanate.  In an example a hydogenated polybutadienediol with Mn of 2000 Da was reacted with 4,4′-MDI together with PTMEG 1000 and BDO in toluene.  At a hardblock content of 35% the TPU showed a Shore hardness of 80A, 250MPa tensile strength and an elongation at break of 520%.

PIB

Hydrogenated (1,2) polybutadiene