Title: METHOD FOR PRODUCING POLYURETHANE PARTICLES

 Number/Link: US2013/0224376

Applicant/Assignee: Konishi Co.

Publication date: 29-08-2013

“Gist”: A PU latex is prepared from an emulsion of an NCO-prepolymer in water which is crosslinked with a  triamine in the presence of hydrophilic silica particles. The latex is then spray dried to form oil absorbing particles.

Why it is interesting: An NCO-ended IPDI-PTMEG prepolymer is dispersed in water an then crosslinked with a triamine.  To the resulting latex, hydrophilic silica particles are added and the composition is then sprayed into a high temperature atmosphere to evaporate the water and form the particles. The size of the silica particles is about 20 nm and a factor 30 smaller then the PU particles. The silica supposedly covers the PU particles so that they do not cohere and show good flow properties. The particles can be used to absorb natural  fats and oils (triglycerids)   Useful (I assume) in the pharmaceutical, cosmetic and agricultural industries (controlled release, perfumes, repellents..)

lab spraydryer schematic (Wikipedia)