TPU Aerosol

Title: POLYURETHANE AEROSOL COMPOSITIONS, ARTICLES, AND RELATED METHODS

Number/Link: US20170198150

Applicant/Assignee: 3M

Publication Date: 13-july-2017  (priority PCT)

“Gist”: Aqueous dispersion of a hydrazide-extended  TPU can be sprayed as aerosol to make protective films

Why it is interesting: An aqueous thermoplastic polyurethane dispersion is prepared from a non-yellowing diisocyanate, e.g. bis(4-isocyanatocyclohexyl), a diol (e.g. PPG2000), a difunctional hydrazine or hydrazide chain extender (e.g. 1,3-diaminourea) and a water solubilizing compound (e.g. dimethylolpropionic acid).  Together with a propellant the, composition is shelf-stable and can be aerosol-sprayed to form clear, non-yellowing protective films.

3M’s aerosol-sprayed protective film.

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)

TPU Foams

Title: POLYURETHANE FOAMS AND METHOD FOR PRODUCING SAME

Number/Link: US2017/0174818

Applicant/Assignee: Lubrizol

Publication Date: 22-june-2016 (PCT oct. 2015)

“Gist”: TPUs with specific MW and polydispersity are injection moulded together with cellopener and gas in supercritical state

Why it is interesting: The invention relates to injection moulded “flexible foams”, especially useful for footwear applications. Thermoplastic polyurethanes with a Mw of 120,000 to 500,000 and a dispersity index of 1.85 to 2.51 are foamed using a gaseous blowing agent (CO2 or C1 to C6 hydrocarbons etc. ) together with a cellopener (silicone or EO/PO surfactant), such that at least 50% of cells are open.  In the examples the blowing agent is added in supercritical state to the melt before injection moulding. The type of gas used, nor the densities of the foams are mentioned.  Foaming TPU with gas in supercitical has also been file by Nike as discussed before in this blog.

Nike shoe with foamed thermoplastic midsole

 

TPU from Oleic Acid

Title: RENEWABLY DERIVED THERMOPLASTIC POLYESTER-BASED URETHANES AND METHODS OF MAKING AND USING THE SAME

Number/Link: US2017/0145145

Applicant/Assignee: Trent University

Publication Date: 25-may-2017

“Gist”: Thermoplastic polyurethane made entirely from C9 monomers derived from oleic acid.

Why it is interesting: Azaleic acid can be prepared by oxidative cleavage of the oleic acid double bond.  Azaleic acid in turn can be converted to 1,9-nonanediol and to 1,7-heptamethyldiisocyanate via azides and Curtius rearrangment (see previous blog post). In this invention a polyester diol is prepared from azaleic acid and nonanediol and is then reacted with 1,7-heptamethylenediisocyanate together with nonanediol as chain extender, resulting in a phase-separated TPU. Best properties are obtained when the nonanediol is first prepolymerized with the diisocyanate. The TPU is said to degrade without cytotoxic degradation products, and is therefore useful for medical applications such as resorbable implants and scaffolds.
Related case: US2017/0145146.

Oleic Acid

 

Crystalline High-Hardblock TPU

Title: CRYSTALLINE HIGH MODULUS THERMOPLASTIC POLYURETHANE

Number/LinkWO2017079101  WO2017079188

Applicant/Assignee: Lubrizol

Publication Date: 11 May 2017

“Gist”: High-hardblock TPU using ‘stacking’ chain extenders and MDI

Why it is interesting: Thermoplastic polyurethanes with hardblock levels of 75% and higher were first patented by Upjohn in 1981 in a “classic” patent which has been discussed before in this blog. These materials – often marketed under the ‘ISOPLAST’ tradename- are usually produced from a diol, 4,4′-MDI and a (mixture of) chain extender(s) comprising a ‘non-stacking’ chain extender like cyclohexanedimethylol, neopentylglycol, MPdiol etc. to control crystallinity. In the current invention only ‘stacking’ chain extenders are used in an otherwise identical composition, resulting -unsurprisingly- in a more crystalline material with a higher modulus and melting temperature. It is also said that these materials are easier to compound with e.g. fire retardants.
Even if this idea were formally ‘new’ I doubt its inventiveness and therefore its patentability.

The famous ISOPLAST(TM) nail