Silicone Hydraulic Fluids

Abstract

The present invention relates to a hydraulic fluid composition comprising (A) at least one polydiorganosiloxane; (B) a chlorendate diester; and (C) a lubricant compound which is an antimony or lead compound of a dialkyldithiocarbamate or dialkylphosphorodithioate.

1 . A composition comprising:
 (A) 2 to 99 parts of at least one polydiorganosiloxane selected from
 (A1) 0 to 99 parts of a polydiorganosiloxane having a formula R′R 2 Si—O(Me 2 SiO) w SiR 2 R′ having a viscosity of 1.00×10 −6  m 2 /s to 1.00×10 −4  m 2 /second at 25° C., and 
 (A2) 0 to 99 parts having a formula R′R 2 Si—O(Me 2 SiO) x (MeR a SiO) y SiR 2 R′ having a viscosity of 1.00×10 −5  m 2 /s to 1.00×10 −4  m 2 /s at 25° C., 
    wherein Me represents the methyl group, each R represents a monovalent group selected from hydrocarbon groups containing from 1 to 6 carbon atoms, and halogenated hydrocarbon groups containing from 1 to 6 carbon atoms, each R′ represents a group selected from R groups, the hydride group, and the hydroxy group, w has an average value from 1 to 70, each R a  represents an aryl hydrocarbon group having from 6 to 10 carbon atoms, x has an average value from 5 to 50, and y has an average value from 0.5 to 6;   (B) 0.9 to 60 parts by weight of a chlorendate diester having the formula R″O 2 CQCO 2 R″, wherein —O 2 C—QCO 2 — represents the chlorendate residue,   
       
         
           
           
               
               
           
         
          each R″ represents a group selected from alkyl groups containing from 4 to 10 carbon atoms and the tetrahydrofurfuryl group; and 
         (C) 0.1 to 38 parts by weight of a lubricant compound selected from N,N-dialkyldithiocarbamates of lead and antimony and dialkylphosphorodithioates of lead and antimony, the total parts of (A) plus (B) plus (C) being 100 parts by weight. 
       
     
     
         2 . The composition of  claim 1  wherein component (A) comprises at least two polydiorganosiloxanes selected from (A1) 1 to 99 parts of a polydiorganosiloxane having a formula R′R 2 Si—O(Me 2 SiO) w SiR 2 R′ and a viscosity of 1.00×10 −6  m 2 /s to 1.00×10 −4  m 2 /second at 25° C. and (A2) 1 to 99 parts of a polydiorganosiloxane having a formula R′R 2 Si—O(Me 2 SiO) x (MeR a SiO) y SiR 2 R′, wherein Me represents the methyl group, each R represents a monovalent group selected from hydrocarbon groups containing from 1 to 6 carbon atoms, and halogenated hydrocarbon groups containing from 1 to 6 carbon atoms, each R′ represents a group selected from R groups, the hydride group, and the hydroxy group, w has an average value from 1 to 70, each R a  represents an aryl hydrocarbon group having from 6 to 10 carbon atoms, x has an average value from 5 to 50, and y has an average value from 0.5 to 6 
     
     
         3 . The composition of  claim 1  where R is methyl, R′ is methyl, R a  is phenyl, R″ is 2-ethylhexyl, R′″ is propyl, w has an average value from 3 to 35, x has an average value of from 11 to 37, y has an average value of 3 to 4, 30 to 40 parts of Component (A1) having a viscosity of 5.00×10 −6  m 2 /second to 3.00×10 −5  m 2 /second at 25° C., 50 to 60 parts of Component (A2) having a viscosity of 2.00×10 −5  m 2 /second to 5.00×10 −5  m 2 /second at 25° C., 4.5 to 10 parts of Component (B), 0.5 to 10 parts of Component (C) where component (C) is a dipropylphosphorodithioate. 
     
     
         4 . In a process of transmitting power from one place to another place via a hydraulic fluid, the improvement which comprises using as the hydraulic fluid the composition of  claim 1 .