Oxidation stability of hydraulic lubricants from vegetable oils

The lubricants produced from petroleum base stock are generally toxic to environment and difficult to dispose after use. Vegetable oils can be used as an alternative base stock for lubricants besides petroleum base because of their excellent lubricity, biodegradability, viscosity characteristic and low volatility. The hydraulic lubricants from vegetable oil were manipulated in this research. Their physical properties including viscosity, viscosity index, flash point and four- ball wear were investigated comparing with those of commercial hydraulic lubricants. OIL-HR, lubricants produced from rice bran oil was exhibited excellent lubricity and viscosity–temperature properties in the same level as commercial industrial lubricants. The oxidation stability of manipulate hydraulic lubricants from soybean oil and rice bran oil under the tested conditions of oven oxidation test in the presence of 0.5% diphenylamine exhibited excellent antioxidant property. The copper corrosion behavior of hydraulic OIL-HC, OIL- HP, OIL-HSF and OIL-HR, lubricants produced from coconut, palm, sunflower and rice bran oil, revealed these blended oils were classified into 1a class, which showed good anticorrosion. The hydraulic lubricant from rice bran oil displayed good anticorrosion and viscosity-temperature characteristic.

以石油基础油制备的润滑油通常对环境具有毒性，且使用后难以处置。植物油凭借优异的润滑性、生物降解性、粘度特性与低挥发性，可作为润滑油基础油的替代原料，取代石油基基础油。本研究针对植物油基液压润滑油开展了调配制备与性能研究。对其粘度、粘度指数（viscosity index）、闪点（flash point）及四球磨损（four-ball wear）等物理性能进行了考察，并与商用液压润滑油的对应性能进行对比。以米糠油制备的OIL-HR润滑油展现出优异的润滑性与粘温性能，其性能水平可与商用工业润滑油相媲美。在添加0.5%二苯胺（diphenylamine）的烘箱氧化试验条件下，由大豆油与米糠油制备的改性液压润滑油展现出优异的抗氧化性能。针对以椰子油、棕榈油、葵花籽油及米糠油制备的OIL-HC、OIL-HP、OIL-HSF与OIL-HR液压润滑油的铜腐蚀行为进行测试后发现，这些调合油均被归类为1a级，具备良好的抗腐蚀性能。米糠油基液压润滑油同时兼具优异的抗腐蚀性能与粘温特性。