Water-based metalworking fluids

There has been much activity in this field of corrosion inhibition in recent years which appears to have been prompted by health and safety requirements. As with engine coolants, the use of nitrites, particularly where amines may also be present, needs to be considered carefully. Nitrites have been widely used in cutting, grinding, penetrating, drawing and hydraulic oils. Suggested replacements for nitrites and/or amines make use, inter alia, of various borate compounds, e.g. monoalkanolamide borates. Molybdates have also been proposed in conjunction with other inhibitors, e.g. carbox-ylates, phosphates, etc . Water-based metalworking fluids usually contain other additives in addition to corrosion inhibitors, e.g. for hard-water stability, anti-foam, bactericidal proderties and so on. Thus, claims are made for oil-in-water emulsions with bactericidal and anti-corrosion properties. 

Chemical complexes of various transition metals have been shown to promote N-nitrosation (28). These metal complexes include ferrocyanide, ferricyanide, cupric ion, molybate ion, cobalt species, and mercuric acetate. All of the reactions are thought to proceed by oxidation-reduction mechanisms. However, such promotion may not be characteristic of transition metal complexes in general, since ferricyanide ion has been shown to promote nitrosation in metalworking fluids, whereas ferric EDTA does not (2 0). Since the metalworking operation generates metal chips and fines which build up in the fluids, this reaction could be of significance in the promotion of nitrosamine formation in water-based metalworking fluids. 

Piebenga WP, van der Walle HB. Allergic contact dermatitis from l-[2-(2,4-dichlorophenyl)-2-(2-propenyloxy) ethyl]-IH-imidazole in a water-based metalworking fluid. Contact Dermatitis 2003 48(5) 285-6. 

Carry-off from work pieces is 2.5 kg/site/year for small user (100-L capacity) and 2,500 kg/ site/year for larger user (95,000-L capacity) annual losses of CPs from cutting fluid are 48%, 75% and 100% for large, medium and small machine shops, respectively 18% loss of SCCPs to wastewater (733 tons/year in 1998 in the EU) and 3% disposed in landfill from use in metalworking fluids 10% discharged to wastewater from use in water-based metalworking fluids loss of CPs are 18.5% and 31.6% for oil-based and water-based metalworking fluids, respectively. Default emission factors for CPs are 0.02% to air for both types of fluids. 

Uses Defoamer for high gloss aq. coatings, water-based metalworking fluids... 

In contrast to neat oils, water-based metalwork fluids are the most relevant irritants in the automobile industry. The irritant potential of these fluids depends on their different components, the quality of preventive measures and the continuous care of the fluids. Components with an irritating potential are organic acids, amines, emulsifiers, preservatives, biocides, antifoams and system cleaners. Often, the quality of technical care of the metalwork fluid is inversely proportional to the irritant effect. Actually trans-epidermal water loss (TEWL) measurement offers new chances in the evaluation irritant potential of different metalwork fluids (Hiiner et al. 1994). Figure 1 shows such a TEWL measurement. It was confirmed by an intervention study in a metalwork factory that, in contrast to metalwork fluids A and C, fluid B was not associated with irritant contact dermatitis. The amine component seems to play a relevant role in the irritant potential (Lautenschlager et al. 1997), if the pH value does not exceed pH 9.5. The risk of irritant dermatitis, particularly hand eczema, is closely associated with the duration of exposure. In general, an exposure of less than 2 h per day will not cause an irritant hand eczema... 

The sodium salt of N-hydroxy-2-pyridinethiones has a germicidal activity againts yeasts and fungi. Sodium omadine is a 40% aqueous solution of sodium pyrithione. It is used in the metallurgical industry as a component of water-based metalwork fluids, of aceto-polyvinyl lattices, water-based printer s ink, lubricant for synthetic fibers and anti-dandruff shampoos. A case was reported in a metallurgic worker. 

Kalhan, S.N. Mann,J. T Denis,R.A. Sulfonate C ontaining Copolymers as Mist Suppressants in Water-Based Metalworking Fluids. European Publication Reference 08116772A2, (1997)... 

In metalworking plants, microbial contaminated water-based metalworking fluid may be associated with HP (Pseudomonas fluorescens) (Bracker et al. 2003 Freeman et al. 1998 Gordon 2004). 

Coolant Cutting lubricant Cutting oil Metalworking fluid Water-based cutting fluid Water-miscible cutting fluid... 

The microbicide is recommended for use as an industrial preservative for the protection of water-based functional fluids with pH values > 7 such as latex paints, resin emulsions, adhesives, pigment slurries, concrete additives, metalworking fluids. Its compatibility with protein containing formulations is very limited. Normal use levels range between 0.1 and 0.3%. The spectrum of efficacy (see Table 31) covers above all bacteria as is characteristic for a formaldehyde releasing compound. 

Under conditions of application APC releases acrolein only slowly accordingly it does not exhibit short-term efficiency. However, APC is suitable for the purpose of preservation (long-term efficiency) of a great variety of water-based functional fluids, e.g. aqueous dispersions, paints, polymers, amine-free metalworking fluids, cooling water circuits. Addition rates 0.05-0.3%. One has to keep in mind that for the in-can protection considerably smaller doses than suggested by MIC values are required. 

Uses Emulsifier for water-misc. metalworking fluids based on semisynthetics and/ or esters... 

Aqueous-based metalworking fluids of all types contain chemicals which, together with the water present, provide excellent nutrient sources for microorganisms. These organisms, if allowed to proliferate, can cause odors, deterioration of the fluid, and corrosion of machines and parts. 

Poly(alkylene glycol)s are also used as lubricity additives ia water-based synthetic cutting and grinding fluids (36), and ia aqueous metalworking fluids. Under the high frictional heating at the tool or die contact with the workpiece, the polyalkylene glycol comes out of solution ia fine droplets which coat the hot metal surfaces. 

METALWORKING FLUID Fluid applied to a tool and workpieee to eool, lubrieate, earry away partieles of waste and provide eoiTosion proteetion. Generally eomprising neat mineral oils, or water-based materials, or a mixture of the two. Fluids may also eontain emulsifiers, stabilizers, bioeides, eoiTosion inhibitors, fragranees and extreme pressure additives. 

With respect to the Agency, Section 5 of TSCA has made EPA more familiar with trends in the metalworking fluids industry, the chemical components of the fluids, and the interactions between the various components. Major trends in the industry are (1) a shift from the traditional oil-based to the rapidly growing water-based fluids (2) a shift from the use of the nitrosating agent nitrite as a rust inhibitor (3) the use of multifunctional additives and (4) the careful monitoring of various factors and additives associated with these fluids. 

Microorganisms have been shown to catalyze the formation of nitrosamines from secondary amines in the presence of nitrite (26). The amount of nitrosamine formed, however, increased as the basicity of the parent amine decreased, presumably due to the increase in the amount of unprotonated amine present (27). This reaction is especially important with respect to metalworking fluids since water-based fluids are inevitably contaminated by microbes and fungi. Microbes are thought to catalyze nitrosamine formation by lowering the pH of the medium or catalysis by one or more unidentified metabolic products. 

Used in metalworking fluids (both water- and oil-based) In treatment and coating of metal... 

Chem. Descrip. Modified tall oil DEA (1 1), water-based CAS 68153-57-1 EINECS/ELINCS 268-949-5 Uses Corrosion inhibitor, lubricant, and emulsifier for syn. metalworking fluids, sol. and emulsifiable oils, chain lubricants, protective coating oils, rolling oils, emulsion cleaners, oil well drilling, water/min. oil coolants in resin-bonded filters for food contact Regulatory FDA 21 CFR 177.2260 DOT nonregulated Properties Dk. amber liq. sol. in most soivs. oils disp. in water sp.gr. 1.0 g/ml b.p. > 300 F acid no. 5.0-15.0 flash pt. (PMCC) > 200 F pH 8.5-10.5 (1% in DVV) anionic/nonionic 100% cone. 

CAS 2634-33-5 EINECS/ELINCS 220-120-9 Uses Biocide, preservative, bactericide, fungicide for water-based prods, incl. adhesives, polymer emulsions, fountain sol ns., metalworking fluids, and paints preservative for food-contact adhesives, paper, polymer emulsions slimicide for food-contact paper mfg. 

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