METHOD FOR PREPARING A HYDRAULIC FLUID, AND METHOD FOR PREPARING ORTHOSILICATE TESTERS, SUITABLE FOR USE IN THE FOREGOING PROCESS

摘要

1464712 Hydraulic fluid CASTROL Ltd 9 Jan 1974 [10 Jan 1973] 1409/73 Heading C5F [Also in Division C3] A hydraulic fluid comprises an orthosilicate ester of the formula wherein RSP1/SP denotes a propylene glycol monoalkyl ether residue in which the terminal alkyl group contains from 1 to 8 carbon atoms, or a tertiary alkyl group, each of RSP2/SP, RSP3/SP and RSP4/SP independently denote an ethylene or propylene glycol monoalkyl ether residue in which the terminal alkyl group contains from 1 to 8 carbon atoms, or a tertiary alkyl group, provided that (1) when RSP1/SP denotes a propylene glycol monoalkyl ether residue each of RSP2/SP, RSP3/SP and RSP4/SP also denote propylene glycol monoalkyl ether residues, (2) the total number of carbon atoms in RSP1/SP, RSP2/SP, RSP3/SP and RSP4/SP is at least 15, and (3) at least one of RSP1/SP, RSP2/SP, RSP3/SP and RSP4/SP denotes a glycol monoalkyl ether residue, alone or in admixture with conventional hydraulic fluid base stocks and/or conventional additives such as lubricity additives, corrosion inhibitors and antioxidants.