The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 2017
Filed:
Jun. 24, 2013
Bayer Materialscience Ag, Monheim am Rhein, DE;
Covestro Deutschland AG, Leverkusen, DE;
Abstract
The present invention relates to a process for producing a dielectric polyurethane film, in which at least the following steps are performed continuously: I) a mixture comprising: a) a compound containing isocyanate groups and having a content of isocyanate groups of >10% by weight and ≦50% by weight, b) a compound containing isocyanate-reactive groups and having an OH number of ≧20 and ≦150, at least one solvent having a vapor pressure at 20° C. of >0.1 mbar and <200 mbar, at least one wetting additive, is produced, where the sum of the number-average functionalities of isocyanate groups and of isocyanate-reactive groups in the compounds a) and b) is ≧2.6 and ≦6, II) immediately after production thereof, the mixture is applied to a carrier in the form of a wet film, III) the wet film is cured to form the polyurethane film and IV) the polyurethane film is separated from the carrier. The invention further provides a dielectric polyurethane film obtainable by the process according to the invention, a process for producing an electromechanical transducer, and an electromechanical transducer obtainable by this process.