Cross-Linked Melt-Spun Polyurethane Fibers

Title: ISOCYANATE PREPOLYMER COMPOSITION AND CROSSLINKED POLYURETHANE PREPARED THEREFROM

 Number/Link: WO2015/007731

Applicant/Assignee: BASF

Publication date: 22-01-2015

Gist”: Melt spinning a TPU – prepolymer blend.

Why it is interesting: Crosslinked polyurethane fibers are produced by melt-spinning a thermoplastic polyurethane which is melt-blended with a specific isocyanate prepolymer composition.  The prepolymer composition is a mixture of a polymeric MDI and the reaction product of a polyester polyol and an excess of 4.4′-MDI. The polyester polyol is prepared from adipic acid together with 2-methyl-1,3-propanediol (MPdiol) and/or trimethylolpropane. The prepolymer composition is characterized by its low viscosity (probably due to the use of the branched polyester).  The crosslinked fibers show an improved tensile set and temperature resistance.

Polymeric MDI

Polymeric MDI

Polyester Polyol with PDMS Backbone

Title: POLYESTER POLYOL, POLYURETHANE OBTAINED USING THE SAME, PROCESS FOR PRODUCTION THEREOF, AND MOLDED POLYURETHANE

 Number/Link: US2014/0246621

Applicant/Assignee: Mitsubishi Chemical

Publication date: 4-09-2014 (priority PCT)

Gist”: A polyester polyol is prepared from a caboxylic acid-modified PDMS and a polyether diol.

Why it is interesting: A polyester polyol is prepared form a linear polydimethylsiloxane end-capped with carboxylic acid groups and having a molecular weight between about 500 and 4000 together with a polytetramethyleneether glycol with MW of 500 to 2000, such that the PDMS content is about 40% . The use of this polyol in polyurethane elastomers results in modified surface characteristics like reduced tackiness. The invention mentions fibers and films as potential applications, but this could be an interesting polyol for many other applications as well. Interesting idea but probably not new.  Only one claim appears to have survived the filing process.

 

Representation of the polyester polyol according to the invention

Representation of the polyester polyol according to the invention

Classic PU Patent of the Month: Otto Bayer’s Invention of Polyurethane and Polyurea (1937)

Title: Verfahren zur Herstellung von Polyurethanen bzw. Polyharnstoffen

Number/Link: DE728981  (German)

Applicant/Assignee: I.G.Farbenindustrie

Publication date: 12-11-1942

Gist”: Production of polyurethanes by reacting diisocyanates and compounds containing at least two hydroxyl and/or amine groups.

Why it is interesting: This is the patent that marked the start of the polyurethane industry.   It covers both aromatic and aliphatic diisocyanates, notably NDI, MDI, TDI, HDI etc. The examples cover polyurethane and polyurea fibers and films. It is said that Bayer was trying to copy Nylon 6,6, the structure of which is very similar to a PU based on 1,6 hexanediol and 1,6 hexanediisocyanate.  The patent has only one claim:

“PATENTANSPRUCH:
Verfahren zur Herstellung von Polyurethanen bzw. Polyharnstoffen, dadurch gekennzeichnet, daβ man organische Diisocyanate mit solchen organischen Verbindungen
zur Reaktion bringt, die mindestens 2 Hydroxyl- oder Aminogruppen mit austauschbaren Wasserstoffatomen oder mindestens eine Hydroxylgruppe und mindestens eine Aminogruppe ,der genannten Art enthalten.”

Dr. Otto Bayer (1902-1982)

Dr. Otto Bayer (1902-1982)

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