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Lower-Toxicity Metal Cleaning for Molding Operations

March 2, 2020
A new surface-cleaning formulation eliminates NMP to improve metalcasters' environmental footprint.

Q: We want to reduce the environmental impact of the foundry consumables we use in our plant. Is there an available metal cleaner that is less toxic than the standard formulations?

A: Metal cleaners are generally used by metalcasting operations to clean chemical build-up on tooling and handling systems. For example, core- and mold-making equipment will frequently need to have the residue of chemicals used for phenolic urethane cold box (PUCB) and no-bake resin systems cleaned from the surface of the working area.

Most metal cleaners contain a solvent called N-Methyl-2-pyrrolidone (NMP). If you are concerned about the environmental footprint of your foundry or diecasting operation, it's necessary to address the role of this organic compound among the consumable products used there.

NMP is a colorless liquid in a class of dipolar aprotic solvents used in a range of industrial settings because it is nonvolatile, miscible with water, and able to dissolve a diversity of chemical and material compounds. It is used to recover hydrocarbons generated in petrochemical processing, and it's used to dissolve a wide range of polymer formations. In particular, it's used as a surface treatment for metal, textiles, resins, or metal-coated plastics, and as a paint stripper. It's also used in in lithium-ion battery manufacturing, for electrode preparation. NMP has been identified by the EPA as a high-priority chemical based on the risks it poses, and it already has been restricted from use in Europe based on the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH), a European Union regulation addressing the production and use of chemical substances, and their potential harmful effects on humans and the environment.

NMP also is listed as a reproductive toxin on the state of California’s Proposition 65, with the potential for causing developmental toxicity - NMP impacts fetal development and can cause miscarriage and stillbirth.

ASK Chemicals researchers recently developed a metal cleaning formulation that does not contain NMP, called ZIP CLEAN OPTIMA. Unlike NMP-containing metal cleaners this formulation does not require the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) health hazards pictogram.

However, as with all metal cleaners it is important always to read the Safety Data Sheet (SDS). Personal protective equipment such as protective clothing, a respirator, goggles, chemical resistant gloves, and a face shield still are necessary for metalcasting workers using ZIP CLEAN OPTIMA.

Beyond the environmental benefits of the new formulation's reduced toxicity compared to other standard metal cleaners, ASK researchers stress that ZIP CLEAN OPTIMA has other advantages. The highly effective solvent it contains will reduce cleaning time on tooling used with phenolic urethane cold box and no-bake resin systems. It will remove resin film from core boxes, exhaust vents, continuous troughs, and augers. It also removes parting-agent build-up. It has a high flash point and a high boiling point.

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