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

 

TPU with Reduced Blooming

Patent Title: POLYOLS WITH REDUCED CYCLIC OLIGOMER CONTENT AND THERMOPLASTIC POLYURETHANE COMPOSITIONS THEREOF

 Number/Link: WO2017040505

Applicant/Assignee: Lubrizol

Publication date: 9-mar-2017

Gist”: Enzymes are used to remove cyclo-oligomers from polyster polyols

Why it is interesting: It is known that the “blooming” of polyester TPUs (i.e. the fomation of a white surface haze) is caused by the migration of cyclic polyester oligomers to the surface of the TPU. Conventionally these unreactive cyclo-oligomers are removed by e.g extraction, or their formation is prevented by careful choice of diol and diacid as mentioned before in this blog. According to this invention the cyclic polyesters can be removed by treating the polyol with an enzyme. Enzymes of the lipase or cutinase type are immobilized by attachement to an inert and insoluble material and then heated together with the polyol at 70 to 90ºC to ‘cut’ the polyester rings. After treatment of the polyol the immobilized enzyme can be filtrated.

A cyclic diester

Enzymatic Recycling of Polyurethanes

Title: PROCESS FOR THE MATERIAL UTILIZATION OF POLYURETHANES

 Number/Link: WO2013/134801 (German)

Applicant/Assignee: Eurofoam

Publication date: 19-09-2013

Gist”: Use of specific enzymes to break down polyurethane into polyamines and its original (polyether)polyols

Why it is interesting: Chemical recycling of polyurethane by hydrolysis, glycolysis etc. is known but requires high temperatures and sometimes (when supercritical water is used) high pressures.  This can lead to side reactions and the contamination of the recycled raw materials. Enzymatic recycling of polyurethanes is known as well but is mostly limited to polyester polyurethanes and esterase enzymes which break down the ester bonds.  The current invention claims that the use of certain hydrolases of the EC3 class, especially arylacylamidase  EC3.5.1.13 selectively breaks the urethane bond. (EC=enzyme comission number). The reaction can be carried out between 30 and 50°C and at a pH of 9.5 to 11. The resulting polyols and amines can be extracted using a polar solvent. While interesting the proposed process may not be very practical as the example shows that 5 days were needed to recycle a 5 gram sample of a model foam.

Schematic representation of the enzyme catalysed reaction.

Schematic representation of the enzyme catalysed reaction.