Cutting fluid is an indispensable "condiment" in the metal cutting industry, which plays a good role in cooling, lubrication, cleaning and rust prevention in the metal cutting process, which can effectively extend the service life of the tool, reduce production costs and improve product quality. Liquid phase of water-based metal processing has better cooling performance and lower cost than oil-based products, and the proportion of use is increasing year by year. Therefore, green and environmentally friendly water-based processing fluid has become the choice of the vast majority of metal processing enterprises.

At present, the users of water-based cutting system on the market mostly use tap water or groundwater containing more minerals, coupled with the continuous precipitation of free calcium and magnesium ions on the metal processing site, which is easy to form insoluble soap with the main emulsifier in the system, fatty acids, oleic acid and other additives, greatly affecting the life of the system. Therefore, when developing the cutting fluid formula, the hard water stability of the formula should be improved according to the customer's working conditions, regional water quality and other factors. On the one hand, the content of additives such as fatty acid soap and sulfonate can be reduced in the formula, and on the other hand, the anti-hard water agent can be added to improve the stability of the formula.

Selection of anti-hard water agent

At present, most of the common anti-hard water agents are chelating agents, such as ethylenediamine tetraacetic acid and its sodium salt, which can be used for bivalent metal ions in the chelating system, and the resistance to hard water is relatively general. Today, Xiaobian will introduce another anti-hard water agent - ether carboxylic acid.

As a modified product of fatty alcohol polyoxyethylene ether, oleyl alcohol/fatty alcohol polyoxyethylene ether carboxylic acid has the properties of anionic and non-ionic emulsifier, and contains polyoxyethylene groups and carboxylic groups, and neutralizes with alkali to form ether carboxylate, which can improve the dispersion ability of calcium soap in metal cutting fluid, anti-electrolyte stability, and effectively improve the stability of cutting fluid.

The properties of ether carboxylic acids depend mainly on the type of alkyl group and the amount of ethoxy group (EO). Alcohol-ether carboxylic acid embedded a certain number of hydrophilic EO groups in the hydrophilic carboxylic group and hydrophobic long carbon chain, overcoming the shortcomings of anionic surfactants' poor resistance to hard water and the dispersion ability of non-ionic surfactants' calcium soap. The carboxyl group can capture the calcium and magnesium ions in the system after ionization in water, and the EO group of the structural species can disperse them in the system well to reduce the soap precipitation. In general, with the increase of the number of ethoxy (EO), the dispersion ability of calcium soap is also relatively improved, the foam is increased, and the rust prevention performance will be relatively reduced. Therefore, when choosing ether carboxylic acids, it is necessary to choose the appropriate alcohol ether carboxylic acids according to the overall stability of the formula. Alcohol ether carboxylic acid is a kind of emulsifying agent with excellent properties and hard water resistance. Adding alcohol ether carboxylic acid to water-based processing liquid system can significantly improve the hard water resistance and biodegradation ability of the system.

Nowadays, the metalworking liquid system is developing in the direction of long-term non-replacement liquid, which also means that the post-treatment process is becoming more and more demanding. Kao Ether carboxylic acid is committed to extending the service life of products, reducing the cost of waste liquid treatment, effectively extending the oil change cycle of metal processing fluids, and tending to an environmentally friendly system.