| 摘要 |
1,235,885. Paper. WEYERHAEUSER CO. 8 Aug., 1968 [15 Aug., 1967], No. 37956/68. Heading D2B. A dielectric medium comprises a cellulosic paper base having incorporated therein at least one inorganic adsorbent which is an activated metal hydroxide, metal oxide, hydrated metal oxide or silicate of aluminium, a liquid halogenated alkyl, aryl or polynuclear hydrocarbon or mixtures thereof as impregnants which are capable of improving the dielectric properties of the paper base and a stabiliser for the impregnant said adsorbent having an average particle size of up to 2-0 microns and said stabiliser containing the epoxy group The adsorbents are preferably aluminium compounds and the paper base is preferably kraft tissue. The liquid impregnant is preferably chlorinated naphthalene, chlorinated diphenyl, chlorinated benzene or derivatives or mixtures thereof. The adsorbent is preferably in an amount of from 0.1 to 10% by weight of cellulose and may be kaolinite, bentonite, attapulgite or fullers earth. The epoxy compound preferably has the formula: where R and R' which may be the same or different represent hydrogen, alkyl, alkoxy, substituted alkoxy, phenoxy or substituted phenoxy e.g. 4, 4'-bis (2, 3-epoxy propoxy) diphenyldimethylmethane, epoxidised natural unsaturated oils containing no residual saturation e.g. soyabean oil, or glycidyl ether. The epoxy compound may be present in an amount ranging from 0.001 to 5.0% by weight of the impregnant. |
