Electromagnetic converter with a polymer element based on a mixture of polyisocyanate and isocyanate-functional prepolymer and a compound with at least two isocyanate reactive hydroxyl groups

1. An electromechanical converter having at least two electrodes and at least one electroactive polymer element, wherein the polymer element is arranged between two electrodes,

and wherein the polymer element comprises the reaction product of

A) a polyisocyanate

B) a polyisocyanate prepolymer and

C) a compound having at least two isocyanate-reactive hydroxy groups.

2. The electromechanical converter according to claim 1 , wherein the converter comprises one or more selected from the group consisting of a sensor, an actuator and a generator.

3. The electromechanical converter according to claim 1 , where in component

A) comprises a polyisocyanate containing isocyanurate groups or uretdione groups, or a mixture thereof.

4. The electromechanical converter according to claim 1 , where in component

A) comprises a diisocyanate having an NCO functionality ≧2 and having a uretdione, isocyanurate, biuret, iminooxadiazinedione or oxadiazinetrione structure, or a mixture thereof.

5. The electromechanical converter according to claim 1 , where in component

A) comprises a polyisocyanate or a polyisocyanate mixture having a mean NCO functionality of from 2 to 4 containing solely aliphatically or cycloaliphatically bonded isocyanate groups.

6. The electromechanical converter according to claim 1 , where in component

B) comprises a reaction product from the reaction of one or more diisocyanates with one or more hydroxy-functional polyols.

7. The electromechanical converter according to claim 6 , where in the diisocyanates are reacted with hydroxy-functional polyols at a ratio of isocyanate groups to hydroxy groups of from 2:1 to 20:1.

8. The electromechanical converter according to claim 1 , where in component

C) comprises a polyamine or a polyol having at least two isocyanate-reactive hydroxy groups.

9. The electromechanical converter according to claim 1 , where in component

C) comprises a polymeric polyol.

10. A process for the preparation of an electromechanical converter according to claim 1 , said process comprising:

a) preparing at least two electrodes;

b) preparing a polymer element by reaction of a reaction mixture comprising the following components

A) a polyisocyanate

B) a polyisocyanate prepolymer and

C) a compound having at least two isocyanate-reactive hydroxy groups;

and

c) arranging the polymer element between two electrodes.

11. The process according to claim 10 , where in preparation of the polymer element is carried out by application of the reaction mixture to at least one of the electrodes and reaction of the reaction mixture.

12. The process according to claim 10 , where in the reaction mixture of A), B) and C) is dried and/or tempered.

13. The process according to claim 11 , where in the equivalent ratio of the isocyanate groups from A) to the isocyanate groups from B) is from 1:10 to 10:1.

14. An electroactive polymer element, produced from a reaction mixture comprising:

A) a polyisocyanate;

B) a polyisocyanate prepolymer obtainable from the reaction of one or more diisocyanates with one or more hydroxy-functional polyols; and

C) a compound having at least two isocyanate-reactive hydroxy groups,

as wherein the electroactive polymer element comprises an electromechanical element.

15. One of an electronic and an electrical device comprising an electromechanical converter according to claim 1 .

16. One of an electronic and an electrical device comprising an electromechanical converter produced according to the process of claim 10 .