GB1049058A - mprovements in or relating to electrolytes for electrolytic capacitors and capacitors employing same - Google Patents

Abstract

1,049,058. Capacitors. LES CONDENSATEURS SIC SAFCO. Oct. 7, 1964 [Oct. 8, 1963], No. 40863/64. Heading H1M. An electrolytic capacitor comprises an aqueous electrolyte containing anions of at least one aliphatic dicarboxylic acid and cations of an alkanol amine dissolved in a water-alcohol cosolvent containing a buffering agent. The capacitor may be conventionally wound of aluminium foils separated by porous spacers of e.g. cellulose paper or glass-cloth impregnated in the electrolyte. The alcohol may be an aliphatic monohydric or dihydric alcohol e.g. methanol, ethanol, n-propanol, i-propanol, butanol, amyl alcohol, hexanol, ethylene propylene, butylene, diethylethylene or triethylene glycol; or a mixture thereof. The buffer may be boric acid and the alkanolamine may be triethanolamine, tri iso propanolamine, diethanolamine, di iso propanolamine or N- methyldiethanol-amine or a mixture thereof. The aliphatic dicarboxylic acid may be saturated, such as adipic, allomucic, aspartic, azelaic, ethyl malonic, fluoro adipic, fluoroglutanic, fluorosuccinic, glutamic, glutaric, malic, methyl succinic, mucic, pimelic, saccharic, sebacic, succinic, talomucic, or tartaric acids; or unsaturated such as citraconic fumaric, glutaconic, glutinic, itaconic, maleic, mesoconic, mucanic, α dihydromuconic, or # dihydromuconic acids; and may be fluoro, hydroxy, alkyl, or amino substituted. Ammonia and phosphates, chromates and molybdates may be added. The wound capacitors may be protected by plastic, e.g. polyolefine or cellulose polyolefine sheets, canned, and sealed with tar or wax.