US4072620A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical insulating oil
Assignee: Eneos Corp
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Filing: 1976-02-10
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Granted: 1978-02-07
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Expires: 1996-02-10
Abstract
Abstract An electrical insulating oil having excellent oxidation stability, thermal stability, corona resistance and corrosion resistance and, if desired, low-temperature properties, which consist essentially of a blend of a refined oil (I) derived from a paraffin or mixed base crude oil, a refined oil (II) prepared from a lubricating oil fraction of a mineral oil and, if desired, an amorphous ethylene-propylene copolymer (III). The oils (I) and (II) may be blended together in ratios by weight of 80- 99:1- 20. In one embodiment, the copolymer may be added to the blend of the oils (I) and (II) in ratios by weight of 0.001- 1.0 to 100 thereby to obtain an electrical insulating oil having excellent low-temperature properties in addition to the above-mentioned excellent properties.
Inventors
- 👤 Midori Masunaga
- 👤 Yoshiki Kohno
- 👤 Hiroshi Hasegawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:37
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/20; H01B3/22; C; C10; C10M; C10M101/00; C10M101/02; C10M143/00; C10M143/02; C10M169/00; C10M169/04; C10M2203/00; C10M2203/10; C10M2203/1006; C10M2203/102; C10M2203/1025; C10M2203/104; C10M2203/1045; C10M2203/106; C10M2203/1065; C10M2203/108; C10M2203/1085; C10M2205/00; C10M2205/02; C10M2205/022; C10N; C10N2020/00; C10N2020/01; C10N2040/00; C10N2040/14; C10N2040/16; C10N2040/17
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
282 words
An electrical insulating oil consisting essentially of (A) 80 - 99 parts by weight of a refined oil (I) containing not more than 0.25 wt. % of sulphur and more than 25 wt. % to not more than 35 wt. % of aromatic compounds, the refined oil being produced by the steps of: refining with a solvent capable of selectively dissolving aromatic compounds a distillate contained in a fraction having a boiling range of 230° - 430° C at atmospheric pressure obtained by the distillation of a paraffin or mixed base crude oil at atmospheric pressure or the distillation at a reduced pressure of a bottom oil obtained by the distillation of the crude oil at atmospheric pressure thereby to obtain a raffinate from said distillate, hydrofining the raffinate so obtained and dewaxing the thus hydrofined raffinate with a solvent (B) 1 - 20 parts by weight of an unhydrofined refined oil (II) prepared by treating at least with a solid adsorbent a lubricating oil fraction of a mineral oil having a boiling range of 230° - 460° C at atmospheric pressure obtained from a crude oil thereby to obtain a base oil for the electrical insulating oil, the base oil having a total sulphur content of not more than 0.35 wt. %, and (C) 0.001 - 1.0 part by weight per 100 parts by weight of said base oil, of an essentially amorphous ethylene-propylene copolymer (III) having a weight average molecular weight of 10,000 - 200,000 and a propylene content of 10 - 70 mol %, whereby is obtained the electrical insulating oil having a low pour point as well as excellent oxidation stability, thermal stability, corona resistance and corrosion resistance.
Claim 2
Dependent Claim
282 words
An electrical insulating oil consisting essentially of (A) 80 - 99 parts by weight of a refined oil (I) containing not more than 0.25 wt. % of sulphur and more than 25 wt. % to not more than 35 wt. % of aromatic compounds, the refined oil being produced by the steps of: refining with a solvent capable of selectively dissolving aromatic compounds a distillate contained in a fraction having a boiling range of 230° - 430° C at atmospheric pressure obtained by the distillation of a paraffin or mixed base crude oil at atmospheric pressure or the distillation at a reduced pressure of a bottom oil obtained by the distillation of the crude oil at atmospheric pressure thereby to obtain a raffinate from said distillate, hydrofining the raffinate so obtained and dewaxing the thus hydrofined raffinate with a solvent (B) 1 - 20 parts by weight of an unhydrofined refined oil (II) prepared by treating at least with a solid adsorbent a lubricating oil fraction of a mineral oil having a boiling range of 230° - 460° C at atmospheric pressure obtained from a crude oil thereby to obtain a base oil for the electrical insulating oil, the base oil having a total sulphur content of not more than 0.35 wt. %, and (C) 0.001 - 1.0 part by weight per 100 parts by weight of said base oil, of an essentially amorphous ethylene-propylene copolymer (III) having a weight average molecular weight of 10,000 - 200,000 and a propylene content of 10 - 70 mol %, whereby is obtained the electrical insulating oil having a low pour point as well as excellent oxidation stability, thermal stability, corona resistance and corrosion resistance.
Claim 3
Dependent Claim
32 words
An electrical insulating oil according to claim 1, wherein the solvent capable of selectively dissolving aromatic compounds is a member selected from the group consisting of furfural, liquefied sulphur dioxide and phenol.
Claim 4
Dependent Claim
86 words
An electrical insulating oil according to claim 1, wherein the hydrofining is effected at temperatures of about 230° - about 345° C and pressures of at least 25 Kg/cm 2 G in the presence of a catalyst selected from the group consisting of the oxides of metals of Groups VI, IB, and VIII, the catalyst being usually sulphurized prior to its use and supported on a carrier selected from the group consisting of bauxite, activated carbon, Fuller's earth, diatomaceous earth, zeolite, alumina, silica and silica alumina.
Claim 5
Dependent Claim
33 words
An electrical insulating oil according to claim 1, wherein the solvent for dewaxing is a member selected from the group consisting of a benzene-toluene-acetone mixed solvent and a benzene-toluene-methyl ethyl ketone mixed solvent.
Claim 6
Dependent Claim
51 words
An electrical insulating oil according to claim 1, wherein the amorphous ethylene-propylene copolymer is one prepared by introducing ethylene, propylene and hydrogen gases through a homogenizable Ziegler-Natta type catalyst at temperatures usually from about -50° to about 50° C and pressures usually from about 1 to about 20 Kg/cm 2 Absolute.
Claim 7
Dependent Claim
20 words
An electrical insulating oil according to claim 1, wherein the dewaxed hydrofined raffinate is further treated with a solid adsorbent.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-02-06 | 1981-08-08 | 1982-02-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-02-06 | 1985-08-08 | 1986-02-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-02-06 | 1989-08-08 | 1990-02-07 | $7700.00 | Window Closed / Lapsed |