Translucent Rigid Foams

Patent Title: TRANSLUCENT POLYURETHANE FOAMS

 Number/Link: WO2018/178139  WO2018/177987  (German)

Applicant/Assignee:  Covestro

Publication date: 4 October 2018

Gist”: Rigid foam formulation is mixed without air to delay nucleation

Why it is interesting: The invention is about translucent rigid foams which are said to be useful as wall and roof elements such as light strips, light domes and the like.  The foams are based on (pref.) trimerized aliphatic diisocyanates and are blown with water.  The composition is degassed and then mixed without inclusion of air to delay nucleation. The resulting foams have a course cell structure and thick cell struts which apparently allows light to pass through.

 

Desmodur N3900

Asymmetric trimer of HDI (iminooxadiazinedione)

Free Download: Polyurethane Science Scan Nr.14 – August & September 2018

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Temperature Stable Memory Foams

Patent Title: VISCOELASTIC POLYURETHANE FOAMS WITH REDUCED TEMPERATURE SENSITIVITY

 Number/Link: WO2018/169833

Applicant/Assignee:  Covestro

Publication date: 20 September 2018

Gist”: A polyol blend comprising a relatively low-EO monol,  diol and triol is foamed with TDI

Why it is interesting: Viscoelastic or “memory” foams are popular materials for pillows and mattresses. One drawback of these materials is the sensitivity of hardness to room temperature variations. According to this invention the hardness variations can be reduced by preparing the foams form TDI and a polyol blend comprising a monofuntional polyether with an EO content of less than 20%, a polyether diol and a polyether triol both with an EO content of less than 45% together with water, catalysts and other additives. The polyol blend can optionally be made in situ.  The foams show an E'(15°C)/E'(30°C) ratio between 1 and 4, a Tg of less than 20°C (defined as the temperature of max. tanδ),  together with high air flow and tear strength values.

DMTA

DMTA trace of foam according to the invention

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)

 

Novel i-PEEP Polymers

Patent Title:  ISOCYANATE-MODIFIED POLYESTER-EPOXIDE POLYMER COMPOSITIONS

 Number/Link: WO2018/160217

Applicant/Assignee:  Stepan

Publication date: 7 September 2018

“Gist”: Polyester polyols are reacted with isocyanates and polyepoxies

Why it is interesting: The invention is related to isocyanate-modified polyester-epoxy polymers (i-PEEPs) which are said to be a “new class of polymers” useful as adhesives, coatings and elastomers.  The materials are prepared by reacting polyester polyols with both polyisocyanates and polyepoxies at an “i-PEEP index” (=(eqvs iso + eqvs epoxy)/eqvs polyol in %) of 100 to 200. The reaction can be run catalysed at room temperature or optionally un-catalyzed at 40 to 100°C. In the examples aromatic and aliphatic polyester polyols are reacted with polymeric MDI and BPA-DGE – based polyepoxide at different indices to produce elastomers with shore A hardness ranging between 30 and 95.
Interesting materials, although calling them a new class of polymers may be a bit exaggerated.

Bisphenol_A_diglycidyl_ether_200

Bisphenol-A diglycidylether (BPA-DGE)