All posts in category Thermoplastics

Spirocyclic Chain Extenders in TPU

Patent Title: THERMOPLASTIC POLYURETHANE WITH HIGH HEAT RESISTANCE

Number/Link: W02016025421 WO2016025423

Applicant/Assignee: Lubrizol

Publication date: 18-02-2016

“Gist”: Use of spirocyclic chain extenders increases heat resistance of TPU

Why it is interesting: Both these patent applications are about the use of alkylene-substituted spirocyclic diols to improve the heat resistance of thermoplastic polyurethanes. In the WO..21 case the diol is used together with MDI and a polycarbonate diol resulting in high heat resistance TPU useful e.g for cable and wire coatings. In the WO..23 case the spirocyclic diol is used together with MDI and a polyether polyol (PEGs) resulting in TPU with high heat resistance and moisture vapour transmission. The spirocyclic diol used in the examples is 3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane.

3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane

Polyurethane with Thermally Reversible Crosslinks

Patent Title: THERMALLY REVERSIBLE CROSSLINKED POLYURETHANE

Number/Link: WO2016/018956

Applicant/Assignee: Lubrizol

Publication date: 4-02-2016

“Gist”: Diels-Alder adducts of furan and maleimide are used as reversible crosslinks

Why it is interesting: Polyurethanes with thermally reversible crosslinks can be useful: these materials can be processed and recycled as thermoplastics while showing increased mechanical properties and the reduced compression set of thermosets. They can also show self-healing properties in certain circumstances.
According to this invention PU with thermally reversible crosslinks can be prepared by reacting a diisocyanate with a diol containing a furan functional group and then incorporating a polymaleimide. For example: the diol can be prepared by reacting furfurylmethacrylate with thioglycerol and the polymaleimide can be 1,1′-(methylenedi-4,1-phenylene)bismaleimide.
Interesting idea but very similar to WO2015119688 discussed before.

1,1'-(methylenedi-4,1-methylene)bismaleimide

1,1′-(methylenedi-4,1-phenylene)bismaleimide

TPU Powder for SLS

Patent Title: USE OF THERMOPLASTIC POLYURETHANE POWDERS

Number/Link: WO2015/197515 (German)

Applicant/Assignee: Covestro

Publication date: 30-12-2015

“Gist”: TPU with very specific melt properties can be used for selective laser sintering

Why it is interesting: Additive manufacturing and “3D printing” using TPU is not new and has been mentioned before in this blog, e.g. the use of TPU in for fused deposition modelling. Fused deposition modelling is a technique where molten thermoplastics are extruded. In powder-based techniques on the other hand, thin layers of thermoplastic powder are selectively ‘sintered’ together using lasers or IR beams. Powder techniques like laser sintering are said to have economic advantages and allow for the production more complex shapes, but suffer from low mechanical properties and brittleness. According to this application, TPU powders with specific hardness and melt characteristics (as outlined in claim 1) allow for laser-sintered objects with improved mechanical properties. In the examples a TPU is prepared from a butanediol-adipic acid polyester diol, butanediol chain extender and 4,4’MDI. The TPU, together with some ‘fumed’ silica flow-improvement additive, is then cryogenically grinded to an average particle size of less than 150 micron and subsequently used for laser sintering.

Innovation in Polyurethanes

All posts in category Thermoplastics

Spirocyclic Chain Extenders in TPU

Polyurethane with Thermally Reversible Crosslinks

TPU Powder for SLS

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