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US-12626868-B2 - Film capacitor having a resin film including a cured product of a first organic material and a second organic material, and a resin film

US12626868B2US 12626868 B2US12626868 B2US 12626868B2US-12626868-B2

Abstract

A film capacitor that includes: a dielectric film; and a metal layer on at least one surface of the dielectric film. The dielectric film is a resin film made of a cured product of a first organic material having multiple hydroxy groups in a molecule and a second organic material having multiple isocyanate groups in a molecule. An intensity ratio of a first peak at 1680 cm −1 to 1770 cm −1 derived from carbonyl groups in urethane bonds to a second peak at 1560 cm −1 to 1620 cm −1 derived from aromatic rings in a Fourier-transform infrared spectroscopy (FT-IR) spectrum of the resin film is 0.50 to 0.94.

Inventors

  • Shunsuke Akiba

Assignees

  • MURATA MANUFACTURING CO., LTD.

Dates

Publication Date
20260512
Application Date
20240605
Priority Date
20211207

Claims (16)

  1. 1 . A film capacitor comprising: a dielectric film; and a metal layer on at least one surface of the dielectric film, wherein the dielectric film is a resin film made of a cured product of a first organic material having multiple hydroxy groups in a first molecule and a second organic material having multiple isocyanate groups in a second molecule, and an intensity ratio of a first peak at 1680 cm −1 to 1770 cm −1 derived from carbonyl groups in urethane bonds to a second peak at 1560 cm −1 to 1620 cm −1 derived from aromatic rings in a Fourier-transform infrared spectroscopy (FT-IR) spectrum of the resin film is 0.50 to 0.94.
  2. 2 . The film capacitor according to claim 1 , wherein a glass transition temperature of the resin film is 174.3° C. to 192.1° C.
  3. 3 . The film capacitor according to claim 1 , wherein the first organic material includes epoxy groups.
  4. 4 . The film capacitor according to claim 1 , wherein the first organic material is a phenoxy resin.
  5. 5 . The film capacitor according to claim 1 , wherein the second organic material includes an aromatic polyisocyanate.
  6. 6 . The film capacitor according to claim 1 , wherein the second organic material includes a diphenylmethane diisocyanate.
  7. 7 . The film capacitor according to claim 1 , wherein the second organic material includes a tolylene diisocyanate.
  8. 8 . The film capacitor according to claim 1 , wherein a thickness of the resin film is 1 μm to 10 μm.
  9. 9 . A resin film comprising: a cured product of a first organic material having multiple hydroxy groups in a first molecule and a second organic material having multiple isocyanate groups in a second molecule, wherein an intensity ratio of a first peak at 1680 cm −1 to 1770 cm −1 derived from carbonyl groups in urethane bonds to a second peak at 1560 cm −1 to 1620 cm −1 derived from aromatic rings in a Fourier-transform infrared spectroscopy (FT-IR) spectrum of the resin film is 0.50 to 0.94.
  10. 10 . The resin film according to claim 9 , wherein a glass transition temperature of the resin film is 174.3° C. to 192.1° C.
  11. 11 . The resin film according to claim 9 , wherein the first organic material includes also has epoxy groups.
  12. 12 . The resin film according to claim 9 , wherein the first organic material is a phenoxy resin.
  13. 13 . The resin film according to claim 9 , wherein the second organic material includes an aromatic polyisocyanate.
  14. 14 . The resin film according to claim 9 , wherein the second organic material includes a diphenylmethane diisocyanate.
  15. 15 . The resin film according to claim 9 , wherein the second organic material includes a tolylene diisocyanate.
  16. 16 . The resin film according to claim 9 , wherein a thickness of the resin film is 1 μm to 10 μm.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation of International application No. PCT/JP2022/040632, filed Oct. 31, 2022, which claims priority to Japanese Patent Application No. 2021-198588, filed Dec. 7, 2021, the entire contents of each of which are incorporated herein by reference. TECHNICAL FIELD The present description relates to film capacitors and resin films. BACKGROUND ART There is a type of capacitor called a film capacitor that has a structure including a flexible resin film as a dielectric material, a first opposite electrode, and a second opposite electrode opposite to the first opposite electrode across the resin film. Such a film capacitor is produced by, for example, winding or laminating a resin film on which a first opposite electrode is formed and a resin film on which a second opposite electrode is formed. Patent Literature 1 discloses a film capacitor including a dielectric resin film and a metal layer disposed on one surface of the dielectric resin film, the dielectric resin film having a glass transition temperature of 160° C. or higher and a density at 25° C. of 1.22 g/cm3 to 1.26 g/cm3. Patent Literature 1: WO 2021/005822 SUMMARY OF THE DESCRIPTION The film capacitor disclosed in Patent Literature 1 obtains a high dielectric breakdown strength at high temperatures by controlling the density of the film to increase the glass transition temperature of the film. Patent Literature 1 describes increasing the density of the film by adjusting the solids concentration in the resin solution, which is a coating liquid. Increasing the solids concentration, however, increases the viscosity of the coating liquid. Therefore, the thinner the film to be produced, the more challenging it becomes to increase its density. As a result, increasing the dielectric breakdown strength at high temperatures becomes difficult. The present description aims to provide a film capacitor including a resin film exhibiting a high dielectric breakdown strength at high temperatures as a dielectric film. The present description also aims to provide a resin film exhibiting a high dielectric breakdown strength at high temperatures. The film capacitor of the present description includes: a dielectric film; and a metal layer on at least one surface of the dielectric film. The dielectric film is a resin film made of a cured product of a first organic material having multiple hydroxy groups in a molecule and a second organic material having multiple isocyanate groups in a molecule. An intensity ratio of a first peak at 1680 cm−1 to 1770 cm−1 derived from carbonyl groups in urethane bonds to a second peak at 1560 cm−1 to 1620 cm−1 derived from aromatic rings in a Fourier-transform infrared spectroscopy (FT-IR) spectrum of the resin film is 0.50 to 0.94. The resin film of the present description is made of a cured product of a first organic material having multiple hydroxy groups in a molecule and a second organic material having multiple isocyanate groups in a molecule. An intensity ratio of a first peak at 1680 cm−1 to 1770 cm−1 derived from carbonyl groups in urethane bonds to a second peak at 1560 cm−1 to 1620 cm−1 derived from aromatic rings in a Fourier-transform infrared spectroscopy (FT-IR) spectrum of the resin film is 0.50 to 0.94. The present description can provide a film capacitor including a resin film exhibiting a high dielectric breakdown strength at high temperatures as a dielectric film. The present description can also provide a resin film exhibiting a high dielectric breakdown strength at high temperatures. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view schematically showing an example of the film capacitor of the present description. FIG. 2 shows an example of an FT-IR spectrum for calculation of the intensity ratio of a peak derived from isocyanate groups to a peak derived from aromatic rings. FIG. 3 shows an example of an FT-IR spectrum for calculation of the intensity ratio of a peak derived from carbonyl groups to a peak derived from aromatic rings. FIG. 4 shows an example of a storage modulus measurement result of a film. DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film capacitor and a resin film of the present description are set forth. The present description is not limited to the following features and may be suitably modified without departing from the gist of the present description. Combinations of two or more preferred features described in the following are also within the scope of the present description. Film Capacitor The film capacitor of the present description includes a dielectric film and a metal layer disposed on at least one surface of the dielectric film. The film capacitor of the present description, for example, has a columnar shape whose cross section is oblong. An external terminal electrode is formed at each end in the central axis direction of the film capacitor by, for example, metal spraying (metallikon). Herei