All posts in category Isocyanates and Prepolymers

m-Xylylene Diisocyanate for Polythiourethanes

 

Patent Title: ISOCYANATE COMPOSITION FOR OPTICAL LENSES AND PROCESS FOR PREPARING THE SAME

 Number/Link: US2018/0334531

Applicant/Assignee:  SKC

Publication date: 22 November 2018

“Gist”:  m-XDI is prepared from purified m-xylylene diamine and used for improved optical materials

Why it is interesting: Polythiourethanes have a high refractive index, a high transparency and a relatively high impact resistance and their use in optical lenses is well known. In this invention, polythiourethanes are prepared by using ‘pure’ (i.e. 99 to 100%) m-XDI as the isocyanate. The m-XDI is prepared from m-xylylene diamine from which impurities (esp. o-XDA, p-XDA and monoamines) are removed by distillation or crystallization.  Polythiourethanes prepared from 100% m-XDI are said to show improved optical properties such as refractive index, transparency, dispersion (Abbe number), yellowness, cloudiness etc.

XDI

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by Gerhard Bleys on December 3, 2018  •  Permalink
Posted in Elastomers, Isocyanates and Prepolymers
Tagged , , , , ,

Posted by Gerhard Bleys on December 3, 2018

https://purpatents.com/2018/12/03/m-xylylene-diisocyanate-for-polythiourethanes/

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)

 

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by Gerhard Bleys on October 26, 2018  •  Permalink
Posted in Isocyanates and Prepolymers, Thermoplastics
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Posted by Gerhard Bleys on October 26, 2018

https://purpatents.com/2018/10/26/aliphatic-tpu-with-reduced-effloresence/

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

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by Gerhard Bleys on August 28, 2018  •  Permalink
Posted in Isocyanates and Prepolymers, Thermoplastics
Tagged , , , , , , , , , ,

Posted by Gerhard Bleys on August 28, 2018

https://purpatents.com/2018/08/28/reactive-tpu-for-am/

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