Hydrolysable Ureas

Patent Title: DYNAMIC UREA BONDS WITH FAST HYDROLYTIC KINETICS FOR POLYMERS

Number/Link: WO2017/155958

Applicant/Assignee: Univ. Illinois

Publication Date: 14 September 2017

“Gist”: Hindered urea bonds with fast hydrolysis kinetics are prepared from aromatic-sbstituted diamines and diisocyanates

Why it is interesting: Polyurethanes containing thermally reversible hindered urea bonds (HUBs) have been discussed before in this blog. In the current case the HUBs are prepared from aromatic (e.g aryl-) substituted amines and are said to show fast, pH-independent, hydrolysis kinetics. The HUBs can be built into linear or crosslinked polyurethanes or other polymers like polyamides, polycarbonates etc.  The resulting materials are useful for medical applications like drug delivery, water-degradable packaging, self-healing materials and the like.

HUB hysdrolysis

Hydrolysis reaction of phenyl-N-tetrabutyl-N-ethyl urea

 

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PCM Containing PU Gels

Title: Temperature Regulating Polyurethane Gels

Number/Link: US2017/0210961

Applicant/Assignee: Technogel

Publication Date: 27 july 2017

“Gist”: Fatty acid ester PCMs are incorporated into Technogel-type gels without encapsulation

Why it is interesting: Polyurethane gels have been discussed before in this blog. The current invention is about “Technogel-type”  gels, made at low NCO-index and high functionality, that contain phase change materials (PCMs). The PCMs are esters of fatty acids that can be blended in molten state with the low EO polyol to form a clear solution, which is then reacted with isocyanate to form the gel. Despite not being encapsulated or forming a separate phase, the PCMs can reversibly melt and crsytallize while in the fluid phase of the gel. In the examples blends of lauryl laurate (C12-C12) and myristyl myristate (C14-C14) are used as PCM such that the phase change temperature is about 22-38°C.  The gels are said to be useful for ‘close to body’ comfort applications especially for use in matresses to improve sleeping comfort.

Lauryl laurate

 

TPU Shrink Wrap

Title: TPU SHRINK MATERIAL

Number/Link: WO2017/108920

Applicant/Assignee: BASF

Publication Date: 29-jun-2017

“Gist”: Shape memory TPU is used as shrink wrap

Why it is interesting: A thermoplastic polyurethane with a shape-memory is prepared from a diisocyanate, a chain extender and a polyol comprising an ‘aromatic polyester block’, especially a polyethylenetherephthalate block. The composition is chosen such that the TPU has a melting point between 160 and 230ºC and another phase transition between 30 and 80ºC (the “switching temperature”). Films of this material are then stretched at a temperature higher than the switching temperature but below melt temperature and then cooled in stretched state. The stretched films are said to be useful as shrink wrap, especially for foodstuffs. No examples are given.
A surprising application for TPU but hardly a surprising TPU invention i.m.o.

Shrink-wrapped Helicopters (Wikipedia)

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