| abstract |
1,164,062. Hydraulic fluids. UNION CARBIDE CORP. 8 June, 1967 [22 June, 1966], No. 26412/67. Heading C5F. [Also in Division C3] An hydraulic fluid comprises, preferably in the stated weight percentages: (a) a mixed polyoxyethylene-polyoxypropylene copolymer, 10-30%; (b) a monoalkyl ether of triethylene glycol, 40-70%; (c) a monoalkyl ether of diethylene glycol, 10-30%; (d) an antioxidant, 0À5 to 1À5%; (e) sorbitan mono-oleate, 0À5- 2%; (f) a dialkylamine, 0À3-1%; and (g) an alkali metal nitrite 0À05-0À3%. The copolymers, which can have molecular weights of 300-15,000, can be made by reacting a mixture of ethylene oxide and propylene oxide using as a starter, water or a monohydric or dihydric alcohol; they normally contain 50- 75% (by weight) of oxypropylene groups and 25-50% of oxyethylene groups. The monoalkyl ethers of di- and triethylene glycols exemplified are the methyl, ethyl, propyl and butyl ethers. Suitable antioxidants are phenyl α- and #-naphthylamines, t-butyl p-cresol, and a polymerized trimethyl dihydroquinoline. Suitable dialkylamines are dipropylamine, dibutylamine, dipentylamine, and dihexylamine. |