The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 21, 1991
Filed:
Sep. 04, 1987
Atsushi Sato, Tokyo, JP;
Shigenobu Kawakami, Ichikawa, JP;
Keiji Endo, Yokosuka, JP;
Hideyuki Dohi, Yokohama, JP;
Nippon Petrochemicals Company, Limited, Tokyo, JP;
Abstract
An electrical insulating oil composition which comprises 45% by weight or more of at least 2 members selected from the group consisting of (a) m-ethylbiphenyl, (b) p-ethylbiphenyl, (c) o-benzyltoluene, (d) m-benzyltoluene, (e) p-benzyltoluene, and (f) 1,1-diphenylethane; and the remainder of non-condensed bicyclic aromatic hydrocarbons having not more than 17 carbon atoms besides the above 6 components; and is characterized in that, when the temperature of the composition is -40.degree. C., (I) the total quantity of solid phase obtained by calculating according to the following solid-liquid equilibrium equation is 45% by weight or less relative to the total quantity of the composition, and (II) in the liquid phase composition calculated by the following solid-liquid equilibrium equation, the total quantity of the compounds (a) to (f) is 40% by weight or more and the viscosity of this liquid phase is 500 cSt or lower, ##EQU1## wherein X.sub.i is the equilibrium mole fraction of a component i in the liquid phase; .DELTA.H.sub.i.sup.f is a heat of fusion (cal.mol.sup.-1); T.sub.i.sup.f is a meltinig point (K); T is the temperature (K); and R is the gas constant (cal.mol.sup.-1.K.sup.-1).