All posts in category Elastomers

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
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Posted by Gerhard Bleys on December 3, 2018

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

Polyurethane-Graphene Composite

Patent Title: POLYURETHANE FILM COMPRISING GRAPHENE AND PREPARATION PROCESS THEREOF.

 Number/Link: WO/2018/202747

Applicant/Assignee:  Directa Plus

Publication date: 8 November 2018

“Gist”: A PU film containing graphene nano-platelets

Why it is interesting: The invention is about polyurethane-graphene nanocomposites useful as films in textiles for clothing and medical applications. The films are prepared by incorporating into a (commercially available) PU resin, 1-30% (w/w) of graphene nano platelets together with 0.1-5% of (pref.) silica particles as a blocking agent and a solvent to adjust viscosity.  The composition is cured on a flat support as a film of 10 to 100µm thick. It is said that the PU films can a.o. have improved breathability, thermal conductivity, electrical conductivity and antibacterial activity.

Graphene

Graphene (Wikipedia)

 

 

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by Gerhard Bleys on November 12, 2018  •  Permalink
Posted in composites, Elastomers
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Posted by Gerhard Bleys on November 12, 2018

https://purpatents.com/2018/11/12/polyurethane-graphene-composite/

PU Elastomers with Extremely High Elongation

Patent Title:  Polyurethane Elastomer with High Ultimate Elongation

 Number/Link: US2018/0312623

Applicant/Assignee:  UNIV PENNSYLVANIA

Publication date: 1 November 2018

“Gist”: Low hardblock polyurethane-polyurea elastomers are prepared from low unsat diols, HDI and a bulky diamine chain extender

Why it is interesting: The current invention relates to PU  elastomers which are said “to  have the highest reported elongation-at-break among known polyurethane elastomers“. The materials are prepared from an NCO-ended prepolymer consisting of a low unsaturated, low dispersity diol and a symmetric diisocyanate (i.e. no 4,4′-MDI), which is reacted with a “bulky” diamine chain extender. In the examples Acclaim 4200 (polyether diol with OHv 28) is used together with HDI and 2-methyl-1,5-pentanediamine. The elastomer showed an elongation at break of more than 2000%.
Because these materials have a low- and non-aromatic hardblock content, it is my opinion that they show creep rather than elasticity.

methylpentandiamine

2-methyl-1,5-pentanediamine

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by Gerhard Bleys on November 2, 2018  •  Permalink
Posted in Elastomers
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Posted by Gerhard Bleys on November 2, 2018

https://purpatents.com/2018/11/02/pu-elastomers-with-extremely-high-elongation/

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