Open Microcellular Rigid Foams

Patent Title: POLYURETHANE FOAM AND PROCESS FOR PRODUCING SAME

 Number/Link: WO 2018/162372 (German)

Applicant/Assignee:  Covestro

Publication date: 13 September 2018

Gist”: Rigid foam formulation is blown with supercritical carbondioxide

Why it is interesting: Open-celled rigid polyurethane foams are well known and used in vacuum insulation panels. Theoretically the best thermal insulation is obtained with the smallest cell size. According to this invention microcellular rigid foams with a homogeneous cell structure, more than 90% open cells and an average cell diameter of less than 50μm can be prepared by using a rigid foam formulation containing a cellopener and supercritical carbondioxide and allowing it to react and expand in a closed mould. In an example a rigid foam is produced with a density of 67kg/m³, open cell content of 95% and average cell diameter of 17μm.

CO2_phase_diagram

Carbon dioxide (P,T) phase diagram (Wikipedia)

 

Polyurethane Oil Gel

Patent Title: OIL GEL, PRESSURE RESISTANT MATERIAL USING SAME FOR PROTECTING ELECTRONIC DEVICES AND OIL GEL-FORMING AGENT

 Number/Link: WO2018135494  (Japanese)

Applicant/Assignee:  Sec Corp.

Publication date: 26 July 2018

Gist”: A gel from a paraffinic  oil and a compatible linear PU is used as a pressure resistant material for deep-sea applications

Why it is interesting: The invention relates to a PU-oil gel that is used as a kind of “potting compound” to protect subsea electronics at “abyssal depths” , i.e. at pressures of 5.6 MPa (about 550m deep). The gel is prepared by reacting a hydrophobic diol and a hydrophobic diisocyanate in the presence of 10-50% (w/w) on the total composition of a paraffinic oil. In the examples an OH-ended, saturated polyisoprene is used as diol together with norbornanediisocyanate.

NBDI

2,5-norbornane diisocyanate

Foamed and Coloured TPU Pellets

Patent Title: PROCESS FOR DYEING AND FOAMING THERMOPLASTIC POLYURETHANE

 Number/Link: WO2018/091446

Applicant/Assignee:  Huntsman

Publication date: 24 May 2018

Gist”: TPU pellets are both coloured and foamed using supercritical carbon dioxide.

Why it is interesting: According to this invention, coloured and foamed thermoplastic polyurethanes can be prepared by saturating TPU pellets (in an autoclave under controlled temperature and pressure) with supercritical CO2 together with a dye.  After impregnation is complete the pressure is dropped at a temperature between the TPU’s Tg and Tm, resulting in expanded TPU pellets or ‘beads’.  The process has the advantage of allowing for the use of a wider range of dyes as compared to conventional pigment-based colours. The TPU beads are said to be especially useful for the production of shoe-soles colour-matched with textiles.

azo compound

Typical azo compound used in dispersion dyes