Patent GB-740078-A (GB)
Title: Improvements in or relating to hydraulic fluids, lubricants and other functional fluids
Filed: 1951-11-08
Abstract: A functional fluid (e.g. a lubricant, a hydraulic fluid or a filter medium for an air-conditioning system) comprises a mixture of a dialkyl monoaryl phosphate ester having the general formula <FORM:0740078/IV(a)/1> in which R1 and R2 are alkyl groups, each of which may carry one or more inert substituents, and R3 is an aryl group which may carry one or more inert substituents, and a minor proportion of a viscosity index improver compatible therewith which is either (i) a polystyrene having a molecular weight of 10,000-150,000 which has been alkylated with mono-olefins containing 6-15 carbon atoms in the molecule or (ii) a polyalkyl methacrylate having an average molecular weight of 7000-20,000, the alkyl group having from 8 to 10 carbon atoms.  Inert substituents, which may be carried by groups R1 and R2 are nitro groups, aryl groups such as phenyl, or alkoxy groups such as ethoxy, butoxy, and isopropoxy. Suitable aryl groups R3 are phenyl, cresyl, higher-alkyl-substituted phenyl, alkoxy-substituted phenyl, halogen-substituted phenyl and nitro-substituted phenyl groups.  Dialkyl monoaryl phosphates mentioned are amyl iso-amyl phenyl, diamyl phenyl, 2-ethylhexyl methyl phenyl, 2-ethylhexyl sec.-butyl phenyl, 2-ethylhexyl n-butylcresyl, dicapryl phenyl, nonyl n-hexyl o-chlorophenyl, dodecyl decyl phenyl, n-hexadecyl isopropyl cresyl, butoxyethyl 3,5,5-trimethylhexyl cresyl, and butoxyethyl n-octyl o-methoxyphenyl phosphates.  In the examples, compositions are described which consist of (a) polyoctyl methacrylate having a molecular weight of about 12,000 and n-butyl sec.-tetradecyl phenyl phosphate; (b) polyoctyl methacrylate having a molecular weight of about 10,000 and 2-ethylhexyl n-butyl phenyl phosphate or 2-ethylhexyl 2-butyloctyl cresyl phosphate; (c) polyoctyl methacrylate having a molecular weight of about 8000 and di-(2-ethylhexyl) phenyl phosphate or 2-ethylhexyl capryl phenyl phosphate; (d) polymerized styrene having a molecular weight of about 65,000 which has been alkylated with C9 mono-olefins and n-octyl n-butyl phenyl phosphate; (e) polymerized styrene having a molecular weight of about 60,000 which has been alkylated with C12 mono-olefins and n-hexadecyl isopropyl phenyl phosphate; and (f) polymerized styrene having a molecular weight of about 70,000 which has been alkylated with C8 mono-olefins and 2-ethylhexyl sec.-butyl cresyl phosphate.ALSO:A lubricating composition, or a hydraulic fluid with lubricating properties, comprises a mixture of a dialkyl monoaryl phosphate ester having the general formula <FORM:0740078/III/1> in which R1 and R2 are alkyl groups each of which may carry one or more inert substituents and R3 is an aryl group which may carry one or more inert substituents, and a minor proportion of a viscosity index improver compatible therewith which is either (i) a polystyrene having a molecular weight of 10,000-150,000 which has been alkylated with mono-olefins containing 6-15 carbon atoms in the molecule or (ii) a polyalkyl methacrylate having an average molecular weight of 7,000-20,000, the alkyl group having from 8 to 10 carbon atoms.  Inert substituents, which may be carried by groups R1 and R2, are nitro groups, aryl groups such as phenyl or alkoxy groups such as ethoxy, butoxy and isopropoxy. Suitable aryl groups R3 are phenyl, cresyl, higher alkyl-substituted phenyl, alkoxy-substituted phenyl, halogen-substituted phenyl and nitro-substituted phenyl groups.  Dialkyl monoaryl phosphates mentioned are amyl iso-amyl phenyl, diamyl phenyl, 2-ethylhexyl methyl phenyl, 2-ethylhexyl sec-butyl phenyl, 2-ethylhexyl n-butyl cresyl, dicapryl phenyl, nonyl n-hexyl ochlorophenyl, dodecyl decyl phenyl, n-hexadecyl isopropyl cresyl, butoxyethyl 3, 5, 5trimethylhexyl cresyl, and butoxyethyl n-octyl o-methoxyphenyl phosphates.  In the examples, compositions are descriped which consist of (a) polyoctyl methacrylate having a molecular weight of about 12,000 and n-butyl sec-tetradecyl phenyl phosphate, (b) polyoctyl methacrylate having a molecular weight of about 10,000 and 2-ethylhexyl n-butyl phenyl phosphate or 2-ethylhexyl 2-butyloctyl cresyl phosphate, (c) polyoctyl methacrylate having a molecular weight of about 8,000 and di (2-ethylhexyl) phenyl phosphate or 2-ethylhexyl capryl phenyl phosphate, (d) polymerized styrene having a molecular weight of about 65,000 which has been alkylated with C9 monoolefins and n-octyl n-butyl phenyl phosphate, (e) polymerized styrene having a molecular weight of about 60,000 which has been alkylated with C12 mono-olefins and n-hexadecyl isopropyl phenyl phosphate and (f) polymerized styrene having a molecular weight of about 70,000 which has been alkylated with C8 mono-olefins and 2-ethylhexyl sec-butyl cresyl phosphate.