| abstract |
COMPOSITION (LIQUID) OF THE CENTRAL HYDRAULIC SYSTEM OR CIRCUIT, CONSISTING OF: 1.70 TO 95 BY WEIGHT OF A HYDROCARBON BASE OIL WITH 2.5 TO 30 OF AN AGENT THAT IMPROVES THE VISCOSITY INDEX. THIS COMPOSITION IS CHARACTERIZED IN THAT BASE OIL 1 CONSISTS OF: A.25 AT LESS THAN 50 OF ITS WEIGHT OF A 1-DECENE OLIGOMER HAVING AN AVERAGE MOLECULAR MASS OF 200 TO 600; AND B. OVER 50 AND UP TO 75 BY WEIGHT OF A FRACTION OF PETROLEUM LUBRICATING OIL, AND IN THAT VISCOSITY IMPROVING AGENT 2 IS A POLYMETHACRYLATE WITH AVERAGE MOLECULAR MASS (ASSESSED BY A VISCOSITY MEASUREMENT) IS BETWEEN 10,000 AND 700,000 WHICH WAS OBTAINED BY POLYMERIZATION OF ONE OR MORE METHACRYLIC ACID ESTERS WITH SATURATED CC ALIPHATIC MONOALCOOLS. THESE COMPOSITIONS MEET SAE STANDARDS AND THEY ALSO HAVE VERY GOOD CHARACTERISTICS AT HIGH TEMPERATURES, SUCH AS FLASH POINT, BEGINNING BOILING POINT AND EVAPORATION LOSS, AS WELL AS GOOD COMPATIBILITY WITH RUBBER HYDRAULIC PARTS. . |