Highly crosslinked polymer dielectric films for improved capacitor performance

Patent metadata

Field	Value
Publication number	US-9611346-B2
Application number	US-201414292349-A
Country	US
Kind code	B2
Filing date	May 30, 2014
Priority date	Jun 6, 2013
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

New polymeric dielectric materials are provided for high power capacitors, especially for mobile and weapons applications. These materials utilize aminoplast crosslinking in their polymeric structure. The aminoplast crosslinking ability of these materials allows them to be customized for a number of applications, but also allows the materials to have a higher crosslinking density, leading to higher dielectric constants, higher breakdown voltage, and higher thermal stability. These materials can be incorporated into current capacitor manufacturing schemes with little to no processing changes.

First claim

I claim:

1. A method of forming a dielectric film, said method comprising:
providing a composition comprising an aminoplast dispersed or dissolved in a solvent system, wherein said aminoplast is present in said composition in an amount from 35% to about 95% by weight, based upon the total weight of said composition taken as 100% by weight; and
forming said composition into a free-standing dielectric film.

2. The method of claim 1 , wherein said aminoplast is selected from the group consisting of ureas, glycolurils, melamines, amides functionalized with formaldehyde, polymers of the foregoing, and mixtures of the foregoing.

3. The method of claim 1 , wherein said aminoplast comprises a structure selected from the group consisting of

wherein:
each R 1 is individually selected from the group consisting of —H, alkyls, ringed moieties, —C═O, and polymer chains;
each R 2 is individually selected from the group consisting of ringed moieties and polymer chains; and
each R 3 is individually selected from the group consisting of —H and alkyls.

4. The method of claim 3 , wherein said aminoplast comprises a structure selected from the group consisting of (III), (IV), (V), and (VI), and at least one other comonomer unit.

5. The method of claim 1 , said composition further comprising an acid catalyst.

6. The method of claim 1 , wherein said forming comprises subjecting said composition to a process selected from the group consisting of spin coating, melt extrusion, draw bar forming, and bubble molding.

7. The method of claim 6 , wherein said forming comprises:
applying said composition to a substrate by a process selected from the group consisting of:
spin-applying said composition to a substrate to form a layer of said composition on said substrate; and
applying said composition to a substrate and drawing said composition with a bar to form a layer of the composition on the substrate;
crosslinking said layer to form a crosslinked film; and
removing said crosslinked film from said substrate to yield said free-standing dielectric film.

8. The method of claim 1 , wherein said forming includes crosslinking a layer of said composition so as to form a dense and highly crosslinked dielectric film.

9. The method of claim 8 , wherein said film exhibits no measurable T g .

10. The method of claim 8 , wherein said film, when subjected to high potential testing, exhibits a % change in dielectric strength of less than about 20% up to 150° C.

11. The method of claim 8 , wherein said film does not create char when discharged.

12. The method of claim 1 , wherein said composition is substantially free of polymers other than the aminoplast.

13. The method of claim 1 , wherein said composition further comprises a polymer that is not an aminoplast.

14. The method of claim 1 , wherein said aminoplast is present in said composition in an amount from about 50% to about 95% by weight, based upon the total weight of said composition taken as 100% by weight.

15. A dielectric film comprising a crosslinked aminoplast, said film being a dense and highly crosslinked film, and said film further being free-standing, wherein said film is formed from a composition comprising from 35% to about 95% by weight of said aminoplast, based upon the total weight of said composition taken as 100% by weight.

16. The film of claim 15 , wherein said aminoplast is selected from the group consisting of ureas, glycolurils, melamines, amides functionalized with formaldehyde, polymers of the foregoing, and mixtures of the foregoing.

17. The film of claim 15 , wherein said aminoplast comprises a structure selected from the group consisting of

wherein:
each R is individually selected from the group consisting of —H, alkyls, ringed moieties, —C═O, and polymer chains;
each R 2 is individually selected from the group consisting of ringed moieties and polymer chains; and
each R3 is individually selected from the group consisting of —H and alkyls.

18. The film of claim 17 , wherein said aminoplast comprises a structure selected from the group consisting of (III), (IV), (V), and (VI), and at least one other comonomer unit.

19. The film of claim 15 , wherein said film is substantially free of polymers other than the aminoplast.

20. The film of claim 15 , wherein said film further comprises a polymer that is not an aminoplast.

21. The film of claim 15 , wherein said film exhibits no measurable T g .

22. The film of claim 15 , wherein said film, when subjected to high potential testing, exhibits a % change in dielectric strength of less than about 20%.

23. The film of claim 15 , wherein said film does not create char when discharged.

24. The film of claim 15 , wherein said film is formed from a composition comprising from about 50% to about 95% by weight of said aminoplast, based upon the total weight of said composition taken as 100% by weight.

Assignees

• Brewer Science Inc

Inventors

• Weimer Marc

Classifications

• H01G4/32

  Wound capacitors · CPC title

• C08F120/58 Primary

  containing oxygen in addition to the carbonamido oxygen {, e.g. N-methylolacrylamide, N-acryloyl morpholine} · CPC title

• H01G4/18

  of synthetic material, e.g. derivatives of cellulose (H01G4/16 takes precedence) · CPC title

• Y10T428/31855

  Of addition polymer from unsaturated monomers · CPC title