Patent GB-777100-A (GB)
Title: Stabilized hydraulic fluid composition
Filed: 1955-09-27
Abstract: A composition for use as an hydraulic fluid comprises 85 to 97 per cent by weight of a tetra-alkyl silicate or hexa-alkyl disilicate having alkyl groups of from 1 to 18 carbon atoms each, from 3 to 15 per cent by weight of a dialkyl silicone polymer having alkyl groups of from 1 to 15 carbon atoms each and a viscosity of at least 1000 centistokes at 77 DEG  F., and from 0.1 to 5 per cent by weight of a secondary diarylamine having from 8 to 24 carbon atoms in alkyl groups positioned on the aromatic nuclei. The silicate has the general formula <FORM:0777100/IV(a)/1> where n is 1 or 2, and the R's are alkyl groups of 1 to 18 carbon atoms; examples are tetraethyl silicate, tetra-(2-butyl)-silicate, hexa-(nbutyl) - disilicate, tetra - (n - octyl) - silicate, tetra - (2 - methyl - 1 - butyl) - silicate, tetra-(2-methyl - 2 - butyl) - silicate, tetra - (2 - hexyl) - silicate, tetra - (2 - ethyl - 1 - butyl) - silicate, tetra - (2 - heptyl) - silicate, tetra - (2 - octyl) - silicate, tetra - (2 - ethyl - 1 - hexyl) - silicate, and hexa - (2 - ethylbutoxy) - disiloxane.  The dialkyl silicone polymer has the general formula <FORM:0777100/IV(a)/2> where n is an integer and the R's are alkyl groups of 1 to 5 carbon atoms; examples are dimethyl silicone, diethyl silicone, methylethyl silicone, dipropyl silicone, dibutyl silicone, diamyl silicone, methylbutyl silicone, and methylamyl silicone.  The silicone preferably has a viscosity between 60,000 and 2 1/2 million centistokes at 77 DEG  F.  The secondary diarylamine has the general formula <FORM:0777100/IV(a)/3> where Ar is an aryl group and the R1's and R2's are hydrogen atoms or alkyl, aralkyl, or alkaryl groups of 1 to 16 carbon atoms, the R1's and R2's containing a total of from 8 to 24 carbon atoms; examples are p,p1-dioctyl-diphenylamine, octylated phenyl-a -naphthylamine, dibutyldiphenylamine, butyloctyldiphenylamine, dioctylphenyl - a  - naphthylamine, tributylphenyl - ethyldiphenylamine, trioctylphenyl-a naphthylamine, and the product obtained by arylalkylating diphenylamine with diisobutylamine and styrene. Examples of compositions are given, some also containing quinizarin.ALSO:A hydraulic fluid with lubricating properties comprises 85 to 97 per cent by weight of a tetra-alkyl silicate or hexaalkyl di-silicate having alkyl groups of from 1 to 18 carbon atoms each from 3 to 15 per cent by weight of a dialkyl silicone polymer having alkyl groups of from 1 to 15 carbon atoms each and a viscosity of at least 1000 centistrokes at 77 DEG F., and from 0.1 to 5 per cent by weight of a secondary diarylamine having from 8 to 24 carbon atoms in alkyl groups positioned on the aromatic nuclei. The silicate has the general formula <FORM:0777100/III/1> where n is 1 or 2, and the R's are alkyl groups of 1 to 18 carbon atoms; examples are tetraethyl silicate, tetra (2-butyl) silicate, hexa (n-butyl) disilicate, tetra (n-octyl) silicate, tetra (2-methyl-1-butyl) silicate, tetra (2-methyl-2-butyl) silicate, tetra (2-hexyl) silicate, tetra (2-ethyl-1-butyl) silicate, tetra (2-heptyl) silicate, tetra (2 - actyl) silicate tetra (2 - ethyl - 1 - hexyl) silicate, and hexa (2-ethylbutoxy) disiloxane.  The dialkyl silicone polymer has the general formula <FORM:0777100/III/2> where n in an integer and the R's are alkyl groups of 1 to 5 carbon atoms; examples are dimethyl silicone, diethyl silicone, dibuty silicone diamyl silicone methylbutyl silicone, and methylamyl silicone.  The silicone preferably has a viscosity between 60,000 and 2 1/2 million centistokes at 77 DEG F.  The secondary diarylamine has the general formula <FORM:0777100/III/3> where Ar is an aryl group and the R1's and R2's are hydrogen atoms or alkyl, aralkyl, or alkaryl groups of 1 to 16 carbon atoms, the R1's and R2's containing a total of from 8 to 24 carbon atoms; examples are p, p1-dioctyl-diphenylamine, octylated phenyl-a -naphthylamine, dibutyldiphenylamine, butyloctyldiphenylamine, dioctylphenyl-a -naphthylamine, tributylphenyl-ethyldiphenylamine, trioctylphenyl-a -naphthylamine, and the product obtained by arylalkylating diphenylamine with diisobutylamine and styrene. Examples of compositions are given, some also containing quinizarin.