# US 10,373,758 B2 · Electrically insulating oil composition, and oil-impregnated electrical equipment

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- Number: US 10,373,758 B2
- Document ID: US10373758B2
- Status: Granted
- Kind: B2
- Application number: 14/917,418
- Filed: 2014-09-05
- Published: 2016-08-04
- Granted: 2019-08-06
- Earliest claimed: 2013-09-12
- Assignees: Jxtg Nippon Oil & Energy Corporation
- Applicants: Jxtg Nippon Oil & Energy Corporation
- Inventors: Takashi Morikita; Hiroyuki Hoshino
- Web page: https://patentgrep.com/patent/US10373758B2

## CPC

- H01G 4/221: {characterised by the composition of the impregnant}
- H01B 3/20: liquids, e.g. oils (silicone oils H01B3/46)
- H01B 3/22: hydrocarbons
- H01G 4/18: of synthetic material, e.g. derivatives of cellulose (H01G4/16 takes precedence)
- 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)
- 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})

## Abstract

It is an object to provide an electrically insulating oil composition that can maintain dielectric breakdown voltage high in a wide temperature range of −50° C. to 65° C., and can suppress a decrease in dielectric breakdown voltage even in the case of use at high temperature for a long time, and there is provided an electrically insulating oil composition comprising 1,1-diphenylethane and benzyltoluene, wherein the proportion of a para isomer in the benzyltoluene is 45% by mass or more based on a total amount of the benzyltoluene.

## Claims

### Claim 1

An electrically insulating oil composition comprising:
1,1-diphenylethane; and
benzyltoluene,
wherein the proportion of a para isomer in the benzyltoluene is 50% by mass or more based on a total amount of the benzyltoluene, such that a decrease in dielectric breakdown voltage of the electrically insulating oil composition is suppressed during its use between 50° C. and 80° C. for 1,000 hours or more.

### Claim 2 (depends on 1)

The electrically insulating oil composition according to claim 1, wherein a total content of the 1,1-diphenylethane and the benzyltoluene is 80% by mass or more based on a total amount of the electrically insulating oil composition.

### Claim 3 (depends on 1)

The electrically insulating oil composition according to claim 1, further comprising 0.01 to 1.0% by mass of an epoxy compound based on the total amount of the electrically insulating oil composition.

### Claim 4 (depends on 1)

The electrically insulating oil composition according to claim 1, wherein a chlorine component is 50 ppm by mass or less.

### Claim 5 (depends on 1)

Oil-impregnated electrical equipment impregnated with the electrically insulating oil composition according to claim 1.

### Claim 6 (depends on 5)

The oil-impregnated electrical equipment according to claim 5, being an oil-impregnated capacitor using a polypropylene film at least in part as a dielectric.