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. 12, 1992
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
A new electrical insulating oil composition having improved low temperature characteristics which composition comprises a mixture of 40% by weight or more of benzyltoluene and the remainder of alkyl substituted diphenylmethane having 15 to 17 carbon atoms which is represented by the following general formula: ##STR1## wherein R.sub.1 and R.sub.2 are C.sub.1 to C.sub.4 alkyl groups and the total number of carbon atoms in R.sub.1 and R.sub.2 is 1 to 4, with the proviso that R.sub.1 and R.sub.2 may not simultaneously be methyl groups and the proportion of the total quantity of solid phase calculated according to the following general solid-liquid equilibrium equation is 45% by weight or less relative to the total quantity of said composition at -40.degree. C.: ##EQU1## where X.sub.i is the equilibrium mole fraction of a component i, in the liquid phase, .DELTA.H.sub.i.sup.f is the heat of fusion (cal.mol.sup.-1), T.sub.i.sup.f is the melting point (K), T is the temperature (K) system, and R is the gas constant (cal.mol.sup.-1.K.sup.-1).