Synthetic ester oils offer outstanding lubricity and excellent load carrying characteristics; ester oils are ideal for metal on metal wear prevention and so are often chosen for high speed metal gear applications. Esters are the reaction products of acids and alcohols; there are three basic types which are normally classified first by the alcohol followed by the type of acid. Ester summary:
- Temperature range of -60 to 150°C
- Affinity to metal/polarity of molecule – attracts to metal surfaces, providing a lubricious film
- Excellent load carrying capability/wear reduction
- Esters can have plastic and elastomer compatibility problems, particularly with ABS and PC so read our compatibility article for more guidance.
- Hydrolytic stability is an issue under certain conditions
- Viscosity Index 75 to 190
Keep in mind that if an Ester is used as the base oil for a grease, the thickener and additives also used in the formula will have an influence on the final characteristics and performance of the finished grease/lubricant.
Take a look at our typical thickener systems characteristics used to make a base oil into a grease.