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

Viscoelastic Polyurethane Elastomers

Title:  IMPACT PROTECTION FOAM

Number/Link: US2017/0233519

Applicant/Assignee: Dow

Publication Date: 17 august 2017

“Gist”: Viscoelastic foams are prepared from MDI, castor oil and a hydrophilic polyether polyol.

Why it is interesting: According to this invention energy absorbing foams with relatively low density and a low hardness and resilience in the temperature range from about -10 to +40°C, can be produced by reacting a blend of hydrophilic and hydrophobic polyols containing castor oil, about 0.5 pbw water and some catalyst and chain extender with MDI.  The examples show foams of about 500 kg/m³ with hardness below shore 50A and ball rebound below 15% at both -10 and +23°C. The foams are said to be useful for impact-protective garments.

Castor oil

Castor oil component

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