Cutting fluid emulsions produced by dilution of a cutting fluid concentrate containing a cationic/nonionic surfactant mixture

A cutting fluid concentrate has been formulated from a paraffinic oil, a hard water, MonoEthanolamine Borate (MEAB) and a cationic/nonionic surfactant mixture. Its dilution with hard water yields very stable oil-in-water emulsions, the so-called cutting fluid emulsion, with an average droplet diameter of 50 nm, independently of both the hardness of water and the weight ratio of hard water to concentrate. The high stability of these emulsions results from the existence of a strong repulsive potential between droplets which is caused in particular by the presence of the cationic surfactant at their surface. From a practical point of view, the ability to produce stable cutting fluid emulsions for a wide range of dilution, whatever the hardness of water, might allow the user to fine-tune the lubricating and cooling abilities of the fluids and therefore optimize their performances during the metal working process.