WATER BASED SEMI-SYNTHETIC METAL WORKING FLUID COMPOSITION CONTAINING AN ALKYL ALCOHOL AMINE

Abstract

The current invention relates to a novel class of alkyl alcohol amines where the amine is a primary amine. Embodiments relate to a method of controlling microbial growth in metal working fluids, comprising adding such an alkyl alcohol amine to the metal working fluid. Other embodiments relate to semi-synthetic metal working fluid compositions which include the microbial growth control agent comprising this particular class of alkyl alcohol amines.

Claims

1. A semi-synthetic metal working fluid, comprising: a. at least one base oil; b. at least one microbial growth control agent comprising an alkyl amine alcohol with the structure of: ##STR00002## where R.sub.1 and R.sub.2 are H, or a C2 to C8 linear, branched or cyclic alkyl group, with the proviso that at least one of R.sub.1 and R.sub.2 is H and at least one of R.sub.1 and R.sub.2 is a C2 to C8 alkyl group; c. one or more organic acid; d. one or more emulsifiers; e. one or more concentrate additives; and f, water.

2. The semi-synthetic metal working fluid of claim 1, wherein R.sub.1 of the microbial growth control agent is H.

3. The semi-synthetic metal working fluid of claim 1, wherein R.sub.2 is a linear alkyl group.

4. The semi-synthetic metal working fluid of claim 1, wherein the microbial growth control agent further comprises another amine.

5. The semi-synthetic metal working fluid of claim 1, wherein the microbial growth control agent comprises monoisobutyanolamine.

6. The semi-synthetic metal working fluid of claim 1, wherein the base oil is selected from naphthenic oils, paraffinic oils, ester oils and mixtures thereof.

7. The semi-synthetic metal working fluid of claim 1, wherein the emulsifier is selected from C16-18 alcohols which have been ethoxylated or propoxylated, ethoxylated C12-C15 alcohols, sodium alkane sulfonate and alky ether carboxylates and mixtures thereof.

8. The semi-synthetic metal working fluid of claim 1, wherein the solubilizer/corrosion inhibitor is selected from ethylhexoic acid, azelaic acid, tall oil fatty acid, 12-hydoxyl-(cis)-9-octadecenoic acid, dicarboxylic acid, 9-octadecenoic acid, sebacic acid, and mixtures thereof.

9. The semi-synthetic metal working fluid of claim 1, wherein the microbial growth control agent is present in an amount of from 6 to 15 percent by weight of the semi-synthetic metal working fluid.

10. The semi-synthetic metal working fluid of claim 1, wherein the base oil is present in an amount of from 10 to 45 percent by weight of the semi-synthetic metal working fluid.

11. The semi-synthetic metal working fluid of claim 1, wherein the emulsifier is present in an amount of from 5 to 20 percent by weight of the semi-synthetic metal working fluid.

12. The semi-synthetic metal working fluid of claim 1, wherein the solubilizer is present in an amount of from 3 to 10 percent by weight of the semi-synthetic metal working fluid.

13. The semi-synthetic metal working fluid of claim 1, wherein the water is present in an amount of from 20 to 60 percent by weight of the semi-synthetic metal working fluid.

14. A composition suitable for use as a microbial growth control agent in a metalworking fluid comprising an alkyl amine alcohol with the structure of: ##STR00003## where R.sub.1 and R.sub.2 are H, or a C2 to C8 linear, branched or cyclic alkyl group, with the proviso that at least one of R.sub.1 and R.sub.2 is H and at least one of R.sub.1 and R.sub.2 is a C2 to C8 alkyl group.

15. The composition of claim 14 where at least one of R.sub.1 and R.sub.2 is a linear alkyl group.

Description

EXAMPLES

[0028] Experiments to test the efficacy of formulations including the presently disclosed microbial growth control agent can be conducted as follows. Table 1 contains a description of the materials used in these examples.

TABLE-US-00001 TABLE 1 Diluted Metalworking Fluid Ingredients Material Type Source Mineral oil Oily agent SCRC EcoSurf SA-7 Emulsifer Dow Dowfax 20A42 Emulsifer Dow Secondary alkane Anionic surfactant SCRC sulphonate Tall oil acid Corrosion agent SCRC Sebacic acid Corrosion agent SCRC Monoisobutanolamine pH adjustor Dow 2-Amino-1-butanol/ pH adjustor Dow Monoisobutanolamine mixture Monoethanolamine pH adjustor Dow Monoisopropanolamine pH adjustor Dow AMP-95 (2-amino-2- pH adjustor Angus Chem methyl-1-propanol) Processing Water Water containing common N/A bacterial agents found in metal working processes Tap Water Water containing 50 ppm N/A metal Aluminum strip Metal TCI (#ADC12) 1,2-epoxybutane Starting material for Sigma-Aldrich (CAS: 106-88-7) synthesis 28% Aqueous ammonium Solvent & starting Sigma-Aldrich hydroxide material for synthesis (CAS: 1336-21-6)

[0029] A series of formulations is prepared according to Table 2, with the different amines listed in Table 3.

TABLE-US-00002 TABLE 2 Material Concentrated Formulation Mineral oil 12.5 wt. % EcoSurf SA-7 7.5 wt. % Dowfax 20A42 5.5 wt. % Secondary alkane 4.5 wt. % sulphonate Tall oil acid 4.5 wt. % Sebacic acid 4.5 wt. % Amine (as indicated 10.7 wt. % in Table 3) Water 50.3 wt. %

TABLE-US-00003 TABLE 3 Diluted water Item Amine type type Example 1 (IE1) Monoisobutyanolamine Processing water Example 2 (IE2) 2-Amino-1-butanol/ Processing Monoisobutanolamine water mixture at 30:70 ratio Example 3 (IE3) Monoisobutyanolamine Tap water Example 4 (IE4) 2-Amino-1-butanol/ Tap water Monoisobutanolamine mixture at 30:70 ratio Comparative Monoisopropanolamine Processing Example 1 water (CE1) Comparative AMP-95 Processing Example 2 water (CE2) Comparative Dicyclohexylamine Processing Example 3 water (CE3) Comparative Monoisopropanolamine Tap water Example 4 (CE4) Comparative AMP-95 Tap water Example 5 (CE5) Comparative Dicyclohexylamine Tap water Example 6 (CE6)

[0030] Examples and comparative examples are water diluted Concentrated Formulation by 20 times.

[0031] The concentrated formulations are prepared as follows. The indicated amount of deionised water is poured into a container. Add mineral oil, Ecosurf SA-7 Dowfax 20A42, secondary alkane sulfonate, tall oil acid and diacid (sebacic acid) into the water. Stir the formulation by magnetic stirrer at 200 rpm at 60 C. for 1 hour. Add the indicated amine as pH adjustor.

[0032] The concentrated formulations are then diluted by processing water or tap water (as indicated in Table, 3) by a factor of 20 times, based on the quantity of the whole concentrated formulation. Test pH value by pH titrator (Mettler Toledo: #SevenMulti). If pH value of the diluted formulation is below 9.5, introduce additional monoethanolamine (1-2 droplets) to increase pH value to at least 9.5.

[0033] pH aging test: test pH value by pH titrator (Mettler Toledo: #SevenMulti) of prepared diluted formulations for 0-day and 14-day. Samples are placed in ambient temperature.

TABLE-US-00004 TABLE 4 pH aging test: Initial pH 1-week aging 2-week aging pH loss Sample # value pH value pH value (%) IE1 9.67 9.43 9.43 2.5% IE2 9.52 9.31 9.31 2.2% CE1 9.55 8.72 8.52 10.8% CE2 9.54 9.29 9.29 2.6% CE3 9.63 9.33 9.30 3.4%

[0034] The pH decrement after 2-week aging should be as small as possible, IE1 with monoisobutylamine, IE3 with 2-amino-1-butanol/monoisobutanolamine mixture and CE2 & 3 with AMP-95 and dicyclohexylamine demonstrate similar level in which pH loss is controlled within 5%. CE1 with monoisopropanolamine is not good in that pH loss exceeds 10%.

[0035] Aluminum corrosion test: Clean the Al strips (#ADC12) with alcohol and weigh strips. Immerse the Al strips into the test solution at 40 C. for 48 hours with capped vials (a half volume of Al strip in solution and a half volume of Al strip exposed to air). Observe the corrosion of Al strip surface, measure weight loss of Al strips and use ICP-OES: inductively coupled plasma-optical emission spectrometer (Perkin Elmer: #Optima 5300DV) to detect Al content in formulations.

TABLE-US-00005 TABLE 5 Aluminum corrosion test: Aluminum content Sample # Corrosion by ICP-OES IE2 pass 0.53 ppm IE4 pass 0.39 ppm CE4 pass 0.11 ppm CE5 marginal 0.42 ppm CE6 fail 2.60 ppm

[0036] The ICP-OES data shows alignment with qualitative observation of aluminum strip corrosion. Larger area with yellow color demonstrates serious corrosion and higher aluminum content in test fluid. The qualitative description pass, marginal or fail are added to comparatively describe the results observed. IE2 with monoisobutylamine, IE4 with 2-amino-1-butanol/monoisobutanolamine mixture and CE4 with isomonopropanoiamine and CE5 with AMP-95 is good at corrosion resistance with less than 1 ppm aluminum leaching from strip. CE6 is worse than any other sample that more than 2 ppm aluminum content has been leaching into fluid.

[0037] Antimicrobial test: Samples are operated under ASTM E 2275 method. This method can be summarized as follows:

[0038] The inoculum is a mixture of ATCC strains of bacteria and fungi as set forth in Table 6. The Emulsion Products Mixed Inoculum is prepared by adding 0.1 mL of each bacterial overnight broth culture and 1.0 mL of each yeast broth culture to the 10 mL of mold suspension and blending.

[0039] 50 grams of sample are dosed with 0.5 ml of the mixed inoculum. This inoculation will challenge emulsion samples with a high level (106-107 Colony Forming Units per gram of sample. CFU/g) of microorganisms, Challenged samples are mixed and stored in the incubator at 30 C. for seven days. This process is repeated for 5 additional rounds of testing with the following amounts of inoculum being added to each sample: 2nd round 0.5 mL; 3rd round 1.0 mL; 4th round 1.0 mL; 5th round 3.0 mL.

[0040] The inoculated emulsion samples are monitored for microbial growth by agar plating using a standard streak plate method. Samples are plated on one and seven days after each microbial challenge. Samples are blended by shaking, vortexing, or stirring with a sterile stick or rod. Samples are uniformly streaked onto TSA and PDA plates preferably using standard 10 L inoculating loops. The streaked agar plates are incubated at 30 C. (TSA) and 25 C. (PDA) for seven days.

[0041] All of the agar plates are checked seven days after plating to determine the number of microorganisms surviving in the test samples. For the plates streaked 7 days post inoculation, no colony growth will be considered a PASS.

TABLE-US-00006 TABLE 6 Microorganisms ATCC # Bacteria: Pseudomonas aeruginosa 10145 Pseudomonas putida 12633 Enterobacter aerogenes 13048 Alcaligenes faecalis 25094 Proteus hauseri 13315 Burkholderia cepacia 21809 Gluconacetobacter 14835 liquefaciens(Asai) Gluconacetobacter 23751 liquefaciens Yeast: Saccharomyces cerivisae 2338 Candida lipolytica 18942 Mold: Aspergillus niger 6275 Penicillium ludwigii 9112

TABLE-US-00007 TABLE 7 Antimicrobial test: Sample Day-1, Day-7, Day-1, Day-7, Day-1, Day-7, Day-1, Day-7, Day-1, Day-7, # Week-1 Week-1 Week-2 Week-2 Week-3 Week-3 Week-4 Week-4 Week-5 Week-5 IE2 Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass IE4 Marg Pass Marg Pass Marg Pass Marg Pass Marg Pass CE4 Fail Fail Fail Fail Fail Fail Fail Fail Fail Fail CE5 Fail Pass Fail Pass Fail Pass Fail Pass Fail Pass CE6 Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass = no colony growth Marg = Marginal = marginal colony growth Fail = significant colony growth

[0042] CE4 with isomonopropanolamine fails in all rounds of the testing. CE5 with AMP-95 can pass the test by the end of week but fails upon first contact with microbe in first day of every round test. IE2 with monoisobutylamine, and CE6 with dicyclohexylamine show good antimicrobial performance that can pass every round trial no matter about day-1 or day-7. IE4 with 2-aamino-1-butanol/monoisobutanolamine mixture can also pass 5 round test and show good performance on day-7, but exhibits slightly worse performance on day-1 versus IE2 and CE6.

[0043] A good amine pH adjustor should pass all of three test items. Thus, monoisobutylamine, 2-amino-1-butanol/monoisobutanolamine mixture, and AMP-95 are qualified, however monoisobutylamine shows the best performance in terms of three testing results.