# US 12,224,125 B2 · Film capacitor

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- Number: US 12,224,125 B2
- Document ID: US12224125B2
- Status: Granted
- Kind: B2
- Application number: 18/188,813
- Filed: 2023-03-23
- Published: 2023-07-20
- Granted: 2025-02-11
- Earliest claimed: 2020-09-23
- Assignees: Shizuki Electric Co., Inc.; Murata Manufacturing Co., Ltd.
- Applicants: Shizuki Electric Co., Inc.; Murata Manufacturing Co., Ltd.
- Inventors: Senichi Ozasa; Tomomichi Ichikawa
- Web page: https://patentgrep.com/patent/US12224125B2

## CPC

- H01B 3/302: {Polyurethanes or polythiourethanes; Polyurea or polythiourea}
- H01G 4/14: Organic dielectrics
- C08G 18/58: Epoxy resins {(C08G18/42, C08G18/48 take precedence; reaction products of epoxy resins with at least equivalent amounts of compounds containing active hydrogen C08G18/6407, with at least equivalent amounts of amines C08G18/6415; polymeric products of isocyanates or isothiocyanates with epoxy compounds having no active hydrogen C08G18/003)}
- C08G 18/7671: {containing only one alkylene bisphenyl group}
- H01G 4/18: of synthetic material, e.g. derivatives of cellulose (H01G4/16 takes precedence)
- H01G 4/32: Wound capacitors
- H01B: CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES (selection for magnetic properties H01F1/00; waveguides H01P {; printed circuits H05K})
- H01G: CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE (selection of specified materials as dielectric H01B3/00; capacitors having potential barriers H10D1/62, H10K10/10)
- C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS

## Abstract

A film capacitor that includes a dielectric resin film made of a thermosetting urethane resin; and a metal layer on at least one surface of the dielectric resin film, wherein the dielectric resin film contains at least an isocyanate group and a carbonyl group, and a ratio of a first absorption peak intensity of the isocyanate group in a wave number range of 2200 cm−1 to 2350 cm−1 to a second absorption peak intensity of the carbonyl group in a wave number range of 1650 cm−1 to 1800 cm−1 is 0.08 to 1.15.

## Claims

### Claim 1

A film capacitor comprising:
a dielectric resin film made of a thermosetting urethane resin; and
a metal layer on at least one surface of the dielectric resin film,
wherein the dielectric resin film contains at least an isocyanate group and a carbonyl group, and
a ratio of a first absorption peak intensity of the isocyanate group in a wave number range of 2200 cm−1 to 2350 cm−1 to a second absorption peak intensity of the carbonyl group in a wave number range of 1650 cm−1 to 1800 cm−1 is 0.08 to 1.15.

### Claim 2 (depends on 1)

The film capacitor according to claim 1, wherein the ratio of the first absorption peak intensity of the isocyanate group to the second absorption peak intensity of the carbonyl group is 0.1 to 1.0.

### Claim 3 (depends on 1)

The film capacitor according to claim 1, wherein the ratio of the first absorption peak intensity of the isocyanate group to the second absorption peak intensity of the carbonyl group is 0.2 to 0.8.

### Claim 4 (depends on 1)

The film capacitor according to claim 1, wherein the dielectric resin film has a moisture content of 0.4 wt % or less.

### Claim 5 (depends on 4)

The film capacitor according to claim 4, wherein the moisture content is 0.01 wt % to 0.4 wt %.

### Claim 6 (depends on 1)

The film capacitor according to claim 1, wherein the dielectric resin film is made of a cured product of a first organic material containing hydroxy groups and a second organic material containing isocyanate groups.

### Claim 7 (depends on 6)

The film capacitor according to claim 6, wherein the first organic material is an organic polymer containing a hydroxyl group and a benzene ring in a repeating unit.

### Claim 8 (depends on 7)

The film capacitor according to claim 7, wherein the organic polymer is a phenoxy resin.

### Claim 9 (depends on 6)

The film capacitor according to claim 6, wherein the second organic material is one of diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate.

### Claim 10 (depends on 1)

The film capacitor according to claim 1, wherein the dielectric resin film includes a crosslinked product of a phenoxy resin and at least one of diphenylmethane diisocyanate or tolylene diisocyanate.

### Claim 11 (depends on 1)

The film capacitor according to claim 1, wherein the film capacitor has a CR value of 250 Ω·F or higher, the CR value being a product of a capacitance of the film capacitor and an insulation resistance of the film capacitor measured after being left in an atmosphere at 125° C. for one hour and subsequently subjected to voltage application of 150 V/μm for one minute.

### Claim 12 (depends on 11)

The film capacitor according to claim 11, wherein the CR value is 250 Ω·F to 5000 Ω·F.