Technical standards provide objective criteria for comparing products. The minimum requirements they establish can also be increased for more demanding applications. A Swiss Armed Forces tender called for five times longer testing. Readily biodegradable MOTOREX HEES hydraulic fluid passed the test easily.

Modern, readily biodegradable (OECD 301 B) hydraulic oils are typical examples of the new, environmentally safe generation of fluids.

There are wide differences in quality among the HEES (hydraulic environmental ester synthetic) raw materials available on the market. MOTOREX uses only high-quality, fully saturated esters to ensure that HEES hydraulic fluid will remain stable and retain its positive characteristics in conformity with DIN ISO 15380, in this case over several times the usual test length. The desired properties (protection against wear, shear stability, lubricating performance, protection against corrosion, resistance to oxidation / aging, etc.) are built into the fluid by combining a precisely tuned additive package with multiple refining steps.

The Swiss Armed Forces invitation to tender called for a five-fold extension of the stringent Cincinnati Milacron Test (CMT), representing extremely strict requirements for the hydraulic fluid. The military is not the only environment where hydraulic systems can remain shut down for extended periods, only to be placed within seconds into heavy-duty service that can continue for hours. Situations like these demand 100 % performance from the fluid. Testing was carried out by an independent laboratory selected by the Swiss Armed Forces. The DIN ISO 15380 standard also requires a second test, the dry Turbine Oil Oxidation Test (TOST). A description of the tests and the results can be found in the box on the next page

In practical use, the effects of water always need to be taken into account when dealing with ester-based hydraulic oils. This is because even fully saturated esters can react with water. As a result, in long-term use it is important to check the condition of readily biodegradable hydraulic fluids at regular intervals.

The two DIN ISO 15380 tests provide a way to compare the products’ performance in a reproducible fashion and calculate a price-performance relationship. By successfully passing the test, MOTOREX not only met the Swiss Armed Forces’ stringent requirements, but provided convincing proof of its capabilities.

The comprehensive MOTOREX range provides the perfect product for every hydraulic application. Your MOTOREX partner will be glad to provide further information.

Two clean, polished, and precisely weighed rods, one of copper and one of steel, are placed in separate beakers of the oil to be tested and heated in an oven at 135 °C for 168 hours. At the end of the test each rod is visually inspected for discoloration and weighed. The sludge that has formed in the oil is also examined. ASTM D 2070

HEES standard test duration¹ 168 hrs.
MOTOREX HEES 1 840 hrs.

¹ Test duration per Swiss Armed Forces invitation to tender

The dry (no water added) TOST uses a glass oxidation cell. A sample of the oil to be tested is placed in the cell along with a catalyst and heated to 95 °C. Oxygen is continuously fed to the sample. The result is shown in hours, indicating the oil’s oxidation lifetime up to a defined degree of acidification ISO 4263-3 / DIN 51554-3

HEES² standard test duration < 600 hrs.
MOTOREX HEES    5208 hrs.

² Meets minimum requirements of ISO 15 380