Title: Highly Insulating Polyurethane Foam and Method for Manufacturing Same

 Number/Link:US2013/0150470

Applicant/Assignee: Cheil Industries

Publication date: 13-06-2013 (priority PCT/KR)

“Gist”: Rigid foams comprising thermally expandable particles which penetrate cell walls and which are covered with an infrared absorbing filler show improved insulation properties.

Why it is interesting: The invention claims to improve insulation properties of rigid foams by including about 5% (on the total resin) of organic thermally expandable particles with a diameter of about 5 μm before expansion and of about 50 μm after expansion. A filler chosen from carbon black, graphite, carbon nanotubes and the like is added as well. After the foam is formed the expanded particles penetrate the cell walls, are supposedly covered with the filler and are believed to reduce the radiation component of the thermal conductivity. Foam properties given in the examples show a density of about 35 kg/m³ with a thermal conductivity of about 0.0160 kcal/m.h.ºC (or about 0.019 W/m.K if I converted this correctly).

Fig 2 form the patent: large circles are the expanded particles, the small circles represent the filler.