Papers by Keyword: Amine-Free

Abstract: The concern for environmental problems has been increasing rapidly in recent years. Water-soluble coolants are widely used in machining processes. To reduce management costs and the environmental load of water-soluble coolants, the authors studied a recycling system for water-soluble coolants. With this recycling system, water is extracted from a waste coolant by chemical or biochemical treatment; the recovered water is re-utilized as a diluent for a new coolant. Coolant recyclability depends on the coolant type. Most water-soluble coolants contain alkanolamines for corrosion inhibition and maintenance of putrefaction prevention. However, alkanolamines are difficult to eliminate from water-soluble coolants by chemical and physical waste treatment processes. Some amine-free, water-soluble coolants have been developed and are commercially available. The reduction of environmental load in the treatment of waste coolants is anticipated for amine-free coolants. We applied the recycling process to a commercially available amine-free, water-soluble coolant. The amine-free coolant showed good recyclability and lubricating performance. However, the corrosion inhibition performance of the coolant was inadequate for use in general machining. Recently, our cooperative company developed a prototype amine-free, water-soluble coolant with improved corrosion inhibition. In this study, we experimentally examined the recyclability and performance stability of this newly developed coolant. The experimental results showed that the new amine-free coolant has good corrosion inhibition equivalent to conventional amine-containing coolants. In addition, the recyclability, stability, and cooling and lubricating performance of the coolant are equal to conventional amine-free coolants. The amine-free, water-soluble coolant with improved corrosion inhibition has the advantage that it can be used in the recycling system for water-soluble coolants.

Abstract: We discussed the coolant composition which can guarantee both the excellent fluid abilities as the cutting fluid and the good treatability as the recyclable material toward the development of sustainable cutting fluid system. We prepared three distinctive coolants; amine-free (EX-102), mineral-oil and amine free (α-1000) and amine-containing (EM-L) coolants. All of the coolants have excellent emulsion stability for standing in the natural condition butα-1000 and EM-L showed a good anti-rust properties while EX-102 showed a rather poor anti-rust property for the cast iron chips. The vegetable oil has a rather poor stability in lubricating performance than that of the mineral oils and synthetic ester. The alkaline substances dissolved in the amine-free coolant can be separated by the surfactant treatment as well as the oil contents, while some alkaline substances, maybe di-ethanol amine, are still retained in the recovered water from the amine-containing coolant. The activated carbon treatment showed no significant change for all of the coolant. Amine-containing coolant forms no stable emulsion; the recovered water cant utilize as a diluents of newly water-soluble coolant while the amine-free coolants can form a stable emulsion to a certain extent. The most direct attack to make the cutting fluid sustainable would be developing a new emulsifier and corrosion inhibitor that can substitute for amine compounds and can show a good treatability like the amine-free cutting fluid.