Abstract An admixture of (1) from 55 to 70 percent by weight of hydrated alumina and (2) from 30 to 45 percent by weight of a petroleum oil extended ethylene-propylene-diene terpolymer, containing from 20 to 100 phr. of oil, is molded about electrical apparatus to provide insulation for components thereof. The hydrated alumina is advantageously finely divided so that a major portion or substantially all particles are less than 2 microns. The terpolymer is derived from the reaction of an admixture of (I) from about 85 to 99 molar percent of a mixture of (a) about 3o to 70 molar percent of ethylene and (b) about 30 to 70 molar percent of propylene and (II) from about 1 to 15 molar percent of a diene having isolated or nonconjugated double bonds, at least one of the double bonds of the diene being terminally located.
The apparatus of claim 1 wherein a major portion of said hydrated alumina has a particle size less than 2 microns.
Claim 2
Dependent Claim
39 words
The apparatus of claim 1 wherein the particulated hydrated alumina has substantially all of its particles of a particle size less than 2 microns and (B) the petroleum oil content is from 50 to 65 phr. of ethylene-propylene-diene terpolymer.
Claim 3
Dependent Claim
31 words
The apparatus of claim 1 wherein said spaced electrically conductive members are elements of a transformer and the insulating material is molded to support and largely surround the electrically conductive members.
Claim 4
Dependent Claim
126 words
A cured organic base electrical insulating composition suitable for prolonged exposure to arcing, tracking and high-voltage stresses under corona conditions consisting essentially of an intimate admixture of (A) from about 55 to 70 percent of a particulated hydrated alumina and (B) from about 30 to 45 percent, by weight, of a petroleum oil extended ethylene-propylene terpolymer consisting essentially of (1) from about 85 to 99 molar percent of a mixture of (a) about 30 to 70 molar percent of ethylene and (b) about 30 to 70 percent of propylene and (2) from about 1 to 15 molar percent of a diene having isolated double bonds, at least one of the double bonds being terminally located, and containing from 20 to 100 phr. of the petroleum oil.
Claim 5
Dependent Claim
21 words
The composition of claim 5 wherein a major portion of the hydrated alumina has a particle size less than 2 microns.
Claim 6
Dependent Claim
21 words
The composition of claim 5 wherein the particle size of substantially all of the hydrated alumina is less than 2 microns.
Claim 7
Dependent Claim
18 words
The composition of claim 5 wherein the petroleum oil is within the range of 50 to 65 phr.
Claim 8
Dependent Claim
142 words
In electrical apparatus having spaced electrically conductive members between which an electrical potential is developed, a cured organic base-insulating material having improved voltage endurance properties disposed between said members, the improvement comprising the insulating material consisting essentially of a vulcanized mixture of (A) from about 55 to 70 percent, by weight, of particulated hydrated alumina and (B) from about 30 to 45 percent, by weight, of a petroleum oil extended ethylene-propylene-diene terpolymer consisting essentially of (1) from about 85 to 99 molar percent of a mixture of (a) about 30 to 70 molar percent of ethylene and (b) about 30 to 70 percent of propylene and (2) from about 1 to 15 molar percent of a diene having isolated double bonds, at least one of the double bonds being terminally located, and containing from 20 to 100 phr. of the petroleum oil.