All posts tagged elastomers

Ionic Liquids for Improved Hydrolysis Resistance of Polyester Polyurethanes

Title: HYDROLYSIS-RESISTANT POLYURETHANE MOULDED ARTICLES MADE OF POLYESTER POLYURETHANE

 Number/Link: WO2014/095438  (German)

Applicant/Assignee: BASF

Publication date: 26-06-2014

“Gist”: Polyester polyurethane elastomers containing carbodiimides, together with an ionic liquid and an amine catalyst in a specific ratio, show improved hydrolysis resistance.

Why it is interesting: Polyester PU elastomers show higher mechanical properties compared to polyether elastomers but have have a much worse hydrolysis resistance.  It is well known that the hydrolysis resistance can be improved by using sterically hindered carbodiimides (commercially known e.g. as Stabaxol®).  This invention shows that hydrolysis resistance can be even more improved by using a specific molecular ratio (pref. 0.5 : 1 to 2 : 1)  of  ionic liquid to amine catalyst in combination with the carbodiimides. The effect is apparent from the examples where 1-ethyl-3-methylimidazolium ethylsulfate was used as ionic liquid together with ethylenediamine as catalyst.  No theory or explanation for the effect is given and it is not immediately clear to me how this interesting synergy works.

Ionic liquid as used in the invention

Ionic liquid as used in the invention

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by Gerhard Bleys on June 30, 2014  •  Permalink
Posted in Elastomers
Tagged , , , , , , ,

Posted by Gerhard Bleys on June 30, 2014

https://purpatents.com/2014/06/30/ionic-liquids-for-improved-hydrolysis-resistance-of-polyester-polyurethanes/

Fuel Resistant Polyurea

Title: POLYUREA COMPOSITIONS AND METHODS OF USE

 Number/Link: US20140171587

Applicant/Assignee: PRC DESOTO

Publication date: 19-06-2014 (priority PCT)

“Gist”: Sulfur-containing polyformal polyols are prepolymerized with aliphatic diisocyanates and then cured with aromatic amines.

Why it is interesting: Sulfur-containing polyformal polyols are prepared from thiodiglycol and paraformaldehyde using acidic catalysis.  The polyols are then reacted with 4,4′-dicylcohexyl diisocyanate (H12MDI) to form a prepolymer which is subsequently cured with an aromatic amine like dimethylthiotoluenediamine. The resulting material is water and fuel resistant and can be used as a sealant in the aerospace industry.

H12MDI-thiodiglycol-polyformal adduct

H12MDI-thiodiglycol-polyformal adduct

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by Gerhard Bleys on June 24, 2014  •  Permalink
Posted in Adhesives-Coatings, Elastomers, Isocyanates and Prepolymers, Polyols
Tagged , , , , , , , , ,

Posted by Gerhard Bleys on June 24, 2014

https://purpatents.com/2014/06/24/fuel-resistant-polyurea/

A New Type of Ultra-Soft Thermoplastic Polyurethanes

Title: THERMOPLASTIC POLYURETHANES WITH CRYSTALLINE CHAIN ENDS

 Number/Link: WO2014/070426

Applicant/Assignee: Lubrizol

Publication date: 8-05-2014

“Gist”: Easily processable, plasticizer-free ultra-soft TPU can be produced by incorporating a crystallizing polyolefin chain stopper.

Why it is interesting: It is well known that TPU with a shore hardness below about 65A is hard to produce and process because of its stickiness and low solidification/crystallization rate. According to the invention this problem can be solved by using a crystalline chain stopper in addition to the polyol, chain extender and di-isocyanate. The chain stopper is (preferably) a c20 to c70 polyolefin mono-alcohol. Apart from improving processability at low hardness, the incoproration of the olefin chain stopper also improves compatibility of the TPU with olefin thermoplastics.  The chain stopper can also be grafted with e.g. a vinyl alkoxysilane to make a hybrid crosslinkable TPU.  An interesting idea with many potential advantages and interesting effects.

Lubrizol logo

Lubrizol logo

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by Gerhard Bleys on May 13, 2014  •  Permalink
Posted in Thermoplastics
Tagged , , , , , , , ,

Posted by Gerhard Bleys on May 13, 2014

https://purpatents.com/2014/05/13/a-new-type-of-ultra-soft-thermoplastic-polyurethanes/

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