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

 Number/Link: WO2018/031356

Applicant/Assignee:  HRL Laboratories

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 oleophilic phase will absorb it, leaving a smudge-free surface.
Question remains what happens when the oily phase gets saturated..

Schematic representation of the invention