Phosgene-Free Polyisocyanate with PDMS Backbone

Patent Title: MULTI-FUNCTIONAL CARBAMATE HAVING SOFT-SEGMENTS, POLYISOCYANATE OBTAINED VIA SUBSEQUENT NON-PHOSGENE SYNTHESIS METHODS, URETHANE PREPOLYMER AND ELASTOMERIC URETHANE HAVING SOFT-SEGMENTS DERIVED THEREFROM, AND PREPARATION METHOD THEREOF

 Number/Link: US20180186918

Applicant/Assignee:  Great Eastern Resins Industrial

Publication date: 5 July 2018

Gist”: Biscarbamate with PDMS softblock backbone is heat-cracked into diisocyanates

Why it is interesting: The invention relates to isocyanate-capped “softblock” siloxanyl prepared without using phosgene and polyurethanes derived therefrom. The invention is accomplished by reacting relatively high MW polydimethylsiloxanediamines with diphenylcarbonate.  The resulting biscarbamate is heated under reduced pressure to produce the diisocyanate and to remove the phenol by-product.  The isocyanates can be reacted with polyols and/or chain extenders to produce highly hydrophobic polyurethanes with low surface tension and good chemical resistance.

biscarbamate

Biscarbamate with PDMS backbone

 

Isocyanate-Free Polyaminal-Polyurethane Foams

Patent Title: SYSTEM FOR DIMENSIONALLY STABLE ISOCYANATE-FREE POLYURETHANE FOAM

 Number/Link: WO2018/005142

Applicant/Assignee:  Dow

Publication date: 4 January 2018

Gist”: Polyaldehydes are reacted with polycarbamates in the presence of an acid catalyst, a metal oxide powder and a blowing agent.

Why it is interesting: According to this invention hydrolytically-stable foams can be prepared from a low molecular weight difunctional aldehyde and a polycarbamate with a functionality of about 3.5 to 4 and an equivalent weight of about 200 to 300, in the presence of a blowing agent and a protic acid as catalyst. Surprisingly the foams are rendered hydrolytically stable by the incorporation of a metal oxide powder with a specific particle size. In the examples polycarbamates are prepared by capping high functionality polyols with methylcarbamate and are then reacted with 1,4-cyclohexanedicarbaldehyde together with p-toluensulfonic acid as catalyst, HFC245fa as blowing agent and MgO powder. The foams show densities of 130-170 kg/m³ and are said to be useful as sealants.

CHDA

Cyclohexanedicarbaldehyde

Sequence-Defined Polyurethanes for Information Storage

Patent Title: UNIFORM SEQUENCE-DEFINED POLYURETHANES AND USES THEREOF AS MOLECULAR LABELS

 Number/Link: WO2017/194694

Applicant/Assignee:  Centre National de la Recherche

Publication date: 16 November 2017

Gist”: Stepwise immobilized polymer synthesis is used to make polyurethane having a predefined sequence of monomers

Why it is interesting: The invention is about monodisperse polyurethanes consisting of a well-defined sequence of monomers having various chain lengths and side groups – not unlike proteins or nucleic acids. In a first step a solid support (e.g. polystyrene beads) which bears a cleavable tether molecule is reacted with N,N’-disuccinimidylcarbonate and in a second step with an aminoalcohol like 5-amino-1-pentanol. Steps 1 and 2 are then repeated using the same or a different aminoalcohol. Finally the tether is cleaved from the support.  If 2 different aminoalcohols are used, a binary code can be encoded in the molecule which can later be read using a sequencing technique. The polyurethanes are said to be useful in anti-counterfeiting technologies.

Capture1

Reaction sequence according to the invention