TLT: How far are we from developing an effective agent that can act as a good buffer as well as a microbiocide?
Clarkson: I don’t see there being one chemistry on the developmental horizon that would function both as an effective buffering agent and a biocide. Here’s why.

Buffering and microbiocidal activity are generally two independent functionalities of chemistries. In a metalworking fluid formulation, buffering and neutralization are traditionally accomplished through the use of amines such as monoethanolamine, triethanolamine and aminomethyl propanol, to name a few. Microbial control in formulations is accomplished through the use of registered biocides at specific treat rates.

However, a number of specialty amines have been shown to extend, or expand, the utility of registered biocides, including butylethanolamine, 3-amino-4-octanol and dicyclohexylamine, to name a few.

TLT: Has ANGUS done any projects working toward that objective? 
Clarkson: No, we are not exploring this avenue. However, in recent years, ANGUS and others have performed numerous studies investigating the performance relationship between amines and other neutralizing agents and registered biocides. 

While ANGUS amino alcohols are not standalone biocidal agents, the in-depth studies we have conducted demonstrate that in laboratory formulations of metalworking fluids, CORRGUARD™ EXT, CORRGUARD™ FLEX and CORRGUARD™ 95 amino alcohols have been shown to enhance performance of registered biocides. This boosting effect helps significantly improve bacterial and fungal control to deliver long-life metalworking fluids with a more favorable environmental health and safety profile, while helping formulators reduce secondary-amine content and optimize the use of approved biocides in their formulations. We expect that future use of specialty amines will continue to increase as formulators look to meet fluid performance requirements while working with an increasingly smaller portfolio of available biocide chemistries.

TLT: Since formaldehyde-producing biocides are on the list of agents likely to be banned by the regulatory authorities, what type of replacement is the industry working on?
Clarkson: There are a multitude of registered biocides available that are not formaldehyde-condensate based. These include BIT, OPP, IPBC and several others. With the increasing regulatory pressure on formaldehyde-producing biocides, we’ve also seen expanded utility of biocides registered in other application spaces into the metalworking fluids space. One example of this is phenoxyethanol, which is widely used in personal care applications. 

TLT: Is it likely that secondary amines and their derivatives could be prohibited in the near future because of some studies showing them as potential carcinogens?
Clarkson: This has already happened in the European market, specifically with the German TRGS 611 regulation that prohibits the addition of secondary amines and limits the levels of secondary amine impurities present in metalworking fluids. While there are a few exceptions to this, formulators and manufacturers are successfully navigating the regulatory changes with next-generation formulations that dramatically reduce or eliminate secondary amine content.

You can reach Nicole Clarkson at nclarkson@angus.com.