Non-Isocyanate Polyurethane Using Thiol-Ene “Click Chemistry”

Title: POLY(HYDROXYL URETHANE) COMPOSITIONS AND METHODS OF MAKING AND USING THE SAME

 Number/Link: US20140182784

Applicant/Assignee:  Inventors but with US goverment interest

Publication date: 3-07-2014

Gist”: Crosslinked poly(hydroxyurethanes) are prepared by reacting a cyclic carbonate comprising a carbon-carbon double bond, a di-thiol and a polyamine.

Why it is interesting: According to this invention hydroxyurethanes are produced by first reacting a cyclic carbonate which has a double bond (e.g. 4-vinyl-1,3-dioxolan-2-one) with a dithiol (e.g. 1,6-hexanedithiol) using UV radiation and a UV initiator. The resulting di-carbonate is then reacted with a polyamine (e.g. diethylene triamine) resulting in a crosslinked poly(hydroxyurethane). Alternatively the carbonate-amine reaction can happen before the thiol-ene ‘click’ reaction. The materials can be used for binders and adhesives a.o.  The reactions have the advantage of being solvent-, catalyst- and isocyanate-free and having a high yield.

Thiol-ene reaction followed by carbonate-amine reaction

Thiol-ene reaction followed by carbonate-amine reaction

Ionic Liquids for Improved Hydrolysis Resistance of Polyester Polyurethanes

Title: HYDROLYSIS-RESISTANT POLYURETHANE MOULDED ARTICLES MADE OF POLYESTER POLYURETHANE

 Number/Link: WO2014/095438  (German)

Applicant/Assignee: BASF

Publication date: 26-06-2014

Gist”: Polyester polyurethane elastomers containing carbodiimides, together with an ionic liquid and an amine catalyst in a specific ratio, show improved hydrolysis resistance.

Why it is interesting: Polyester PU elastomers show higher mechanical properties compared to polyether elastomers but have have a much worse hydrolysis resistance.  It is well known that the hydrolysis resistance can be improved by using sterically hindered carbodiimides (commercially known e.g. as Stabaxol®).  This invention shows that hydrolysis resistance can be even more improved by using a specific molecular ratio (pref. 0.5 : 1 to 2 : 1)  of  ionic liquid to amine catalyst in combination with the carbodiimides. The effect is apparent from the examples where 1-ethyl-3-methylimidazolium ethylsulfate was used as ionic liquid together with ethylenediamine as catalyst.  No theory or explanation for the effect is given and it is not immediately clear to me how this interesting synergy works.

Ionic liquid as used in the invention

Ionic liquid as used in the invention

Fuel Resistant Polyurea

Title: POLYUREA COMPOSITIONS AND METHODS OF USE

 Number/Link: US20140171587

Applicant/Assignee: PRC DESOTO

Publication date: 19-06-2014 (priority PCT)

Gist”: Sulfur-containing polyformal polyols are prepolymerized with aliphatic diisocyanates and then cured with aromatic amines.

Why it is interesting: Sulfur-containing polyformal polyols are prepared from thiodiglycol and paraformaldehyde using acidic catalysis.  The polyols are then reacted with 4,4′-dicylcohexyl diisocyanate (H12MDI) to form a prepolymer which is subsequently cured with an aromatic amine like dimethylthiotoluenediamine. The resulting material is water and fuel resistant and can be used as a sealant in the aerospace industry.

H12MDI-thiodiglycol-polyformal adduct

H12MDI-thiodiglycol-polyformal adduct

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