Aliphatic TPU with Reduced Effloresence

Patent Title: ALIPHATIC THERMOPLASTIC POLYURETHANES, PRODUCTION AND USE THEREOF

 Number/Link:   WO2018/192936 (German)

Applicant/Assignee:  Covestro

Publication date: 25 October 2018

Gist”: TPU based on 1,10-decanediisocyanate shows reduced blooming

Why it is interesting: Aliphatic thermoplastic polyurethanes, based on hexanediisocyanate (HDI) can show “blooming” i.e. the formation of a white precipitate on the surface of the material.  It is believed that this is caused by the formation of cyclic oligourethanes migrating to- and forming crystals on the surface. According to this invention, this blooming behaviour can be prevented by using long-chain aliphatic diisocyanates like 1,10-diisocyanatodecane or 1,12-diisocyanatododecane instead of HDI.

DDI

1,10-diisocyanatohexane (DDI)

 

TPU with Reduced Blooming

Patent Title: POLYOLS WITH REDUCED CYCLIC OLIGOMER CONTENT AND THERMOPLASTIC POLYURETHANE COMPOSITIONS THEREOF

 Number/Link: WO2017040505

Applicant/Assignee: Lubrizol

Publication date: 9-mar-2017

Gist”: Enzymes are used to remove cyclo-oligomers from polyster polyols

Why it is interesting: It is known that the “blooming” of polyester TPUs (i.e. the fomation of a white surface haze) is caused by the migration of cyclic polyester oligomers to the surface of the TPU. Conventionally these unreactive cyclo-oligomers are removed by e.g extraction, or their formation is prevented by careful choice of diol and diacid as mentioned before in this blog. According to this invention the cyclic polyesters can be removed by treating the polyol with an enzyme. Enzymes of the lipase or cutinase type are immobilized by attachement to an inert and insoluble material and then heated together with the polyol at 70 to 90ºC to ‘cut’ the polyester rings. After treatment of the polyol the immobilized enzyme can be filtrated.

A cyclic diester

Polyester TPU with Reduced Blooming

Title: POLYURETHANE BASED ON RENEWABLE RAW MATERIALS

 Number/Link: WO2015/000722

Applicant/Assignee: BASF

Publication date: 8-01-2015

Gist”: Preparing TPU from polyester diols based on a blend of diacids reduces blooming

Why it is interesting: This application relates to polyester polyols prepared from a diol and a mixture of  diacids of which “at least one is at least partly” produced from a renewable resource. When these polyester diols are reacted with a diisocyanate and a chain extender, the resulting TPU shows a reduced tendency to “bloom” (i.e. form a white exudate on the surface). In the examples TPUs based on polyester polyols prepared from 1,3-propanediol and either azaleic- or sebacid acid (all from renewable resources) show very strong blooming while a TPU based on a polyester polyol prepared from 1,3-propanediol and a 1:1 blend of azeleic- and sebacic acid  shows very little blooming. While this an interesting effect, it is not clear to me why “at least one of the diacids needs to be at least partly” made from a renewable resource is claimed. The claim appears unrelated to the actual invention.

Sebacic Acid

Sebacic Acid

  • Pages

  • Categories

  • Enter your email address to follow this blog and receive notifications of new posts by email.

    Join 1,089 other followers

  • Follow Innovation in PU on Twitter

%d bloggers like this: