Triethanolamine is an important additive in water-based cutting fluids. It has multiple functions in water-based cutting fluids:
1.Synthetic water-soluble lubricant
At present, most oily agents with good lubricating properties are water-insoluble. Triethanolamine has three -OH. By controlling the ratio of the raw materials, the -OH in the triethanolamine molecule can react with the oily agent to produce a water-soluble oily agent.
【Note: This should be a substance such as triethanolamine oleic acid soap. 】
2.As an antirust agent
Triethanolamine itself is a water-soluble rust inhibitor. Using it alone can effectively prevent iron and steel from rusting in a short period of time, and it has a synergistic rust preventive effect with rust inhibitors such as borax and sodium carbonate. When used in combination, it can significantly improve the rust preventive ability.
【Note: Triethanolamine has better antirust ability after reaction with carboxylic acid. 】
Triethanolamine is a non-ionic surfactant. Adding it to water-based cutting fluid will help the cutting fluid infiltrate and penetrate the cutting interface, so that it can fully exert the cooling and cleaning effect of water-based cutting fluid.
【Note: This is questionable. Triethanolamine has a certain surface activity, but it is not a surfactant. The reaction product of triethanolamine with carboxylic acids such as DTO is not a surfactant. The surfactant solution has not only surface activity, but also indicators such as ϒcmc, cmc. 】
Oil-based agents, extreme pressure agents, etc. added to water-based cutting fluids are easily water-resolved, thereby reducing the effect of the cutting fluid. Adding a small amount of triethanolamine can stabilize.
【Note: Can the hydrolysis of lubricant additives be inhibited by adding triethanolamine? No such evidence has been found. 】
Triethanolamine is an ideal pH adjuster for water-based cutting fluids. In the later stage of production of water-based cutting fluid, the pH value of the solution is adjusted with triethanolamine, which will not cause other additives to gel and precipitate due to pH changes.
【Note: pH of aqueous triethanolamine solution is ≈ 10.3, which has strong buffering capacity, but the effect of increasing the pH value of the formula is not obvious; pH of aqueous monoethanolamine solution is ≈ 11.4, which raises the pH value quickly, but the buffering capacity is slightly worse. Therefore, more than one compound is used. 】