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

 

Polyols from Natural Oils using the Alkyne Zipper Reaction

Title: POLYURETHANE MATERIALS FORMED FROM UNSATURATED PLANT OILS VIA AN ALKYNE ZIPPER REACTION

Number/Link: US2017/0166679 US2017/0166680

Applicant/Assignee: IBM

Publication Date: 15-june-2017

“Gist”: Oils are turned into alkyne alcohols, ‘zippered’ and oxidized to polyols

Why it is interesting: This is yet  another IBM patent application about interesting, albeit somewhat exotic, chemistry and featuring only “prophetic” examples. In this case unsaturated natural oils are first converted into unsaturated alcohols and then into alkynes by bromination and elimination.  The internal alkynes are then converted to terminal alkynes by an “alkyne zipper reaction” and then into hydroxyl groups by hydroboration and epoxidation/ring-opening. This series of reactions should result in polyols having two primary- and one or more secondary OH groups, useful, for example, for the preparation of sound absorbing foams.

Reaction sequence according to the invention

Preventing Ostwald Ripening in Rigid PU Foams

Title: PRODUCTION OF FINE CELL FOAMS USING A CELL AGING INHIBITOR

Number/Link: WO2017093058  (German)

Applicant/Assignee: Evonik

Publication Date: 8 June 2017

“Gist”: Perfluorinated hydrocabons reduce Ostwald ripnening in PU foam formulations

Why it is interesting: Polymeric foams form by nucleation and growth of gass bubbles in the reacting mixture followed by (or simultaneous with) ageing of the bubbles through coalesence and Ostwald ripening, i.e. the growth of larger bubbles at the expense of smaller bubbles. Ostwald ripening ultimately results in fewer and larger cells, which has a negative effect on the thermal insulation properties of rigid foams. According to this invention the ripening effect can be prevented or reduced by incorporating in the foam formulation an “Ostwald hydrophobe”, i.e. a highly hydrophobic liquid which is largely immiscible with the reacting mixture. Examples of such liquids are perfluorinated hydrocabons with a boiling point of less than 150°C, e.g. perfluoropentane, perfluorocyclohexane and perfluoroisohexene (used in the examples).

Perfluorocyclohexane