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

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

Polyurethanes from Alpha Glucan

Patent Title: POLYURETHANE POLYMERS COMPRISING POLYSACCHARIDES

 Number/Link: WO2018/017789

Applicant/Assignee:  Du Pont

Publication date: 25 january 2018

Gist”: Polyurethanes containing poly alpha 1,3-glucan

Why it is interesting: The invention is related to the preparation of different types of polyurethanes comprising poly alpha 1,3-glucan, which is a polymeric D-glucose having alpha 1,3 glycosidic bonds (as opposed to most natural glucose polymers which show α or β 1,4 glycoside linkages). Alpha 1,3 glucan can be prepared by enzymatic polymerization using sucrose and a glycosyltransferase. The glucan can be mixed with polyols and reacted with isocyanates to prepare polyurethanes.  Many examples are given ranging from PUDs, films, flexible foams to TPUs.

glucan

Poly alpha 1,3-glucan