Thiol-Crosslinked Poly(hydroxyurethanes)

Title: METHOD FOR PRODUCING OR CURING POLYMERS USING THIOL-ENE POLYADDITION REACTIONS

Number/Link: W2017/081120

Applicant/Assignee:  Henkel

Publication Date: 18-05-2017

“Gist”: Unsaturated PHU are crosslinked using polythiols

Why it is interesting: The invention is about poly(hydroxyurethanes) (PHU) containing alkylene groups that are crosslinked using thiol-ene ‘click’ polyaddition reactions. The unsaturated PHU are first prepared by aminolysis of cyclocarbonates using unsaturated amines. In an example di-trimethylolpropane is converted to di-trimethylolpropanedicarbonate using ethylchloroformiate.  The di-TMPDC is then reacted with 3-aminopropylvinylether to prepare the PHU, which is then crosslinked using pentaerithritol-tetra(3-mecaptopropionate) in the presence of a photoinitiator and UV light.  The invention is said to be useful for isocyanate-free adhesive- and coating systems.

Di-trimethylolpropanedicarbonate

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

Matte, Self-Healing Polyurethane Powder Coatings

Title: POLYURETHANE COATING COMPOSITION

Number/Link: WO2017/074835

Applicant/Assignee: Valspar

Publication Date: 4 May 2017

“Gist”: Coating composition comprising isocyanate and two polyester polyols having a similar Tg but a widely different equivalent weight.

Why it is interesting: Conventionally low gloss or “matte” coatings are the result of a microtextured surface achieved by certain fillers or by incompatible polymers and the like. According to this invention “ultra matte” finishes can also -surprisingly- be achieved from a (powder) coating composition comprising a (blocked) isocyanate and a mixture of two polyester polyols. Both polyols have a Tg between 40 and 60ºC prefereably differing not more than 5 to 8ºC, while the OHv of the first polyol is between 150 and 325 and that of the second between 15 and 35.  The ratio between first and second polyol is from about 1:1 to 1:3 w/w. Also surprisingly, the resulting coatings are said to show self-healing properties. An interesting composition but no examples of the polyesters or isocyanates used are given.

Car with matte finish

NEW: Polyurethane Science & Technology Scan

Polyurethane Science & Technology Scan- April 2017, is a quick overview of the most important sci-tech articles of last month.

You can download it for free in exchange for your comments.

 

PU tech scan

Moisture Scavenger for Polyurethane Coatings

Title: PROCESSES FOR MOISTURE SCAVENGING IN PREPARING POLYURETHANE COATINGS AND COMPOSITIONS THEREFOR

Number/Link: US2017/0114247

Applicant/Assignee: Achiewell

Publication Date: 27-april-2017

“Gist”: Methoxysilicon compound with e-withdrawing group together with hydrophobic t-amine catalyst acts as moisture scavenger

Why it is interesting:  Moisture in PU coating compositions can be a problem because it negatively affects both the properties of the composition (pot life and viscosity..) and of the final coating. Moisture scavengers like molecular sieves are well known but often have a negative impact as well. According to this invention, methoxyorganosilicon compounds with at least one electron withdrawing group attached to the silicon atom act as efficient moisture scavengers when used in combination with a hydrophobic tert-methylamine catalyst. Preferred organosilicon compounds have 3 methoxy substituents and one hydrocarbon-based e-withdrawing group, like e.g. fluoroethyltrimethoxysilane. A preferred catalyst is 1,3-bis[3-dimethylaminopropyl]urea (claimed).  No examples are given.

1,3-bis[3-dimethylaminopropyl]urea