Akypo Ether Carboxylic Acids (US)

April 29, 2015

One of the main contributors to metalworking fluid failure, and shortened sump life, in both hard and soft water areas, is increasing hard water salt concentrations over time, due to evaporation. This can lead to corrosion, emulsion instability, and the formation of residues that can interfere with efficient filtration and also provide a substrate for microbial activity.

Aluminum use in automobiles is increasing, introducing aluminum and additional magnesium into systems. These soaps can be particularly troublesome. Dr. Michael Stapels, KAO Chemicals GmbH, will describe this issue in detail at the 70th STLE Annual Meeting and Exhibition. KAO Akypo ether carboxylic acid stabilizers address these issues directly, being hard water soap dispersants and solubilizers. They offer several benefits for formulating robust metalworking fluids, including emulsification, rust protection and increased concentrate stability relative to temperature and concentration. Additionally, these materials are biodegradable, non-toxic, dermatologically mild, and offer low aquatic toxicity.

The KAO Chemicals Akypo range of products are ether carboxylic acids which are used as emulsifiers and stabilizers in metalworking fluids. The alkyl chain length and degree of ethoxylation are varied, providing a range of materials to select from for specific applications and formulations. These structures result in a variety of properties, offering many possibilities to the formulator.

There are two general types of ether carboxylates in the Akypo range: short and long alkyl chain length based. The long chain type are based on C12 to C18 acids, while the short chain materials are based on C4 to C10 acids. Each benefit metalworking fluid formulations in different, but similar ways.

The short alkyl chain length Akypo LF products act as couplers, much like glycol ethers, in metalworking fluid concentrates. They can facilitate the formulation of robust metalworking fluid concentrates by expanding the temperature and concentration ranges where concentrates are clear and stable. This can lead to longer shelf life and more possibilities for highly concentrated fluids. They tend to lower the viscosity of metalworking fluid concentrates, making them more easily emulsified for use. Additionally, they can contribute to rust protection and are low foaming. Short alkyl chain ether carboxylic acids help extend the life of in-use metalworking fluids by solubilizing hard water salts and helping the emulsions tolerate high electrolyte concentrations without becoming unstable. This solubilizing activity has the added benefit of keeping metal surfaces cleaner; minimizing undesirable deposit formation.

The long alkyl chain length Akypo materials are effective co-emulsifiers while offering immediate hard water stability improvement of emulsions. They are used in much the same way as other co-emulsifiers, including fatty acids and nonionics, are used in metalworking fluids, but with additional benefits. They are lime soap dispersing agents which allow calcium soaps to maintain their anti-foaming characteristics. Their Akypo RO 50 VG Akypo RO 90VG Akypo LF 2 Akypo TEC AM VG dispersion of calcium, aluminum and magnesium soaps contributes to longer fluid life by preventing the buildup of the soaps in systems, which can harbor microbial growth and interfere with filtration, and improving emulsion stability. Additionally, these materials can contribute to rust protection and lubricity.

KAO uses world class technology to manufacture Akypo ether carboxylic acids and the products generally contribute significantly to producing robust formulations. They are delivered un-neutralized, providing additional flexibility to the formulator, and a material high in activity, as delivered. When formulating with Kao Akypo materials, either replacing some or all of the glycol ether with the short alkyl chain products, or replacing fatty acid and nonionics content with long alkyl chain materials; It is always preferable to replace instead of adding on top of the formulation, for both cost and performance reasons.