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

Fingerprint Resistant Coatings

Patent Title: COATINGS COMBINING OIL-ABSORBING AND OIL-REPELLING COMPONENTS FOR INCREASED SMUDGE RESISTANCE

 Number/Link: WO2018/032356

Applicant/Assignee:  HRL Laboratorories

Publication date: 15 February 2018

Gist”: Phase separated polyurethanes with oleophilic dispersed phase and oleophobic continuous phase (or vice versa) behave as anti-smudge materials.

Why it is interesting: Anti-smudge coatings are of great interest for smartphones and other touch screen devices and are currently made from oleophobic materials, i.e. materials showing a small contact angle vs. oils. According to this invention improved anti-smudge properties can be achieved by using a material having discrete inclusions in a continuous matrix. The matrix material needs to be oleophilic, while the inclusions are oleophobic (or vice versa) and the inclusions need to be smaller than 50nm so not to scatter visible light.  A coating like this can be prepared from a segmented polyurethane comprising (e.g.) a polybutadiene soft phase and a perfluoro/isocyanate/TMP hard phase. It is said that the oleophobic phase will repel the oil while the oelephilic phase will absorb it, leaving a smudge-free surface.
Question remains what happens when the oily phase gets saturated..

smudgecoating

Schematic representation of the invention

Optical Polyurethane Elastomers

Patent Title: COMPOSITION FOR TRANSPARENT SHAPED BODIES BASED ON POLYURETHANE

 Number/Link: WO2016/113295

Applicant/Assignee: Covestro

Publication date: 21-07-2016

Gist”: Use of amino-chelate-tin complex as delayed action catalyst for transparent PU elastomers

Why it is interesting: Lenses for eyeglasses are increasingly made from transparent organic polymers like polyurethane elastomers. The production requires a specialized casting process into glass moulds, followed by an exact tempering over many hours. According to this invention polyurethane elastomers, useful for the production of eyeglass lenses, can be made form a composition containing a polyol, a cycloaliphatic or araliphatic diisocyanate, an internal mould release agent and a thermo-latent catalyst. The catalyst is an inorganic metal complex comprising Sn (preferred) and at least one tert-amine containing chelating ligand. The composition is said to have a longer ‘open-time’ as the catalyst-free system.

Example of thermo-latent catalyst according to the invention

Example of thermo-latent catalyst according to the invention