Aqueous semi-synthetic metalworking fluid composition containing alkyl alcoholamine

Abstract

The present invention relates to a novel class of alkyl alcohol amines, in which the amines are primary amines. Embodiments relate to methods of controlling microbial growth in metalworking fluids comprising adding such alkyl alcohol amines to the metalworking fluid. Other embodiments relate to semi-synthetic metalworking fluid compositions that include microbial growth control agents that include this particular class of alkyl alcohol amines.

Description

[Technical Field]

[0001] The present invention relates to a new class of alkyl alcohol amines wherein the amine is a primary amine. Embodiments relate to methods of controlling microbial growth in metalworking fluids comprising adding such alkyl alcohol amines to the metalworking fluid. Other embodiments relate to semi-synthetic metalworking fluid compositions comprising a microbial growth control agent comprising this particular class of alkyl alcohol amines.

[0002] Introduction Metalworking fluids (MWFs) are used for lubrication during metal cutting and tool forming operations. These fluids serve to cool metalworking tools, remove cutting debris from the tool / workpiece interface, and provide an acceptable post-machining surface finish. Amines are common MWF components that are widely used in various applications due to their properties of corrosion resistance, neutralization, and pH adjustment. Organic amines are commonly used as corrosion inhibitors, however, MWFs degrade over time due to microbial growth that adversely affects fluid performance, as microbes feed on active ingredients in the fluid.

[0003] Such microbial growth in MWFs can cause serious problems in metalworking operations in many ways, including general acidification of MWFs, changes in MWF viscosity, reduced shelf life of MWFs, and corrosion of tools and materials. In addition, the function of equipment and processes such as supply nozzles, storage tanks, pipelines and recycling system facilities can also be affected by microbial growth in MWFs. This acidification increases the cost of MWFs, accelerates corrosion rates, and reduces the efficiency of metalworking. Therefore, in the MWF industry, there is an unmet need for components that do not support microbial growth and maintain performance over extended periods of time.

[0004] Therefore, the MWF industry has not met the requirements for components that do not support microbial growth and maintain performance over long periods. The most common solution is to add biocides and amine alcohols to a given MWF, either continuously or in batches. However, biocides and some secondary amine alcohols are restricted by regulatory limitations, and most biocidal chemicals release formaldehyde over time, which is harmful to human health.

[0005] Existing MWFs are typically classified as neat oil, soluble oil, semi-synthetic fluid, or synthetic fluid, each category exhibiting different functions such as cooling, lubrication, rust prevention, and cleaning. Soluble oil MWFs contain 50-70% by weight of neat oil, with the remainder being wear-resistant / extreme pressure additives and emulsifiers. Neat oils and soluble oils typically do not provide the same level of cooling as aqueous metalworking fluids. Synthetic fluids typically cannot provide good lubrication performance because their lubricating function is affected by the reverse dissolution of polyalkylene glycol when the temperature is above the cloud point. Semi-synthetic materials offer the potential to provide good lubrication and cooling simultaneously for use in demanding applications. Typical semi-synthetic fluids consist of oil, organic acids, emulsifiers, lubricants, amines, water, and other components. The amount of water in such a semi-synthetic MWF is typically up to 50-60% by weight, along with approximately 10-40% by weight of base oil, approximately 10-20% by weight of emulsifier, approximately 10-20% by weight of amine, and other functional additives such as acids, lubricants, solubilizers, and biocides. The semi-synthetic MWF is usually diluted at the end-user site with additional water to a base oil concentration of 1-20% by weight, more typically 5-7% by weight, by the weight of the diluted formulation.

[0006] In semi-synthetic fluids, emulsifiers are often added to form a stable dispersion in oil-in-water. Emulsifier particles are located around the oil droplets, imparting a negative charge that causes them to bond to water molecules. The size of such emulsified oil droplets is generally crucial for fluid performance, as smaller emulsion sizes allow for easier penetration into the interface of the cleavage zone. Emulsifiers also contribute to the stability of semi-synthetic fluids.

[0007] Semi-synthetic fluids partially degrade over time due to microbial growth, which negatively impacts fluid performance, as microorganisms feed on the active components in the fluid. Such microbial growth in MWF can cause serious problems in metalworking processes in many forms, including common pickling of MWF, changes in MWF viscosity, shortening of MWF shelf life, and corrosion of tools and materials. In addition, the functionality of equipment and processes such as supply nozzles, storage tanks, pipelines, and recycling system equipment can also be affected by microbial growth in MWF. This pickling increases the cost of MWF, accelerates the corrosion rate, and reduces the efficiency of metalworking. The most common solution to control microbial growth is to add biocides and amine alcohols to a given MWF, either continuously or in batches. However, biocides and some secondary amine alcohols are limited by regulatory restrictions, and most biocidic chemicals release formaldehyde over time, which is harmful to human health.

[0008] Therefore, it is desirable to have a novel semi-synthetic metalworking compound having a new biocidal composition that provides improved cooling, lubricity, concentration stability, and a long shelf life without the current environmental hygiene and safety concerns of the fluid.

[0009] The present invention addresses at least some of the needs described above. [Overview of the project]

[0010] The present invention relates to a novel class of alkyl alcohol amines in which the amine is a primary amine. The present invention also relates to a method for controlling microbial growth in a metalworking fluid, the method comprising adding at least one such alkyl alcohol amine to the metalworking fluid. The present invention also describes an aqueous semi-synthetic metalworking fluid comprising a base oil, an organic acid, an emulsifier, a concentrate additive, water, and a microbial growth control agent comprising a novel alkyl alcohol amine. [Modes for carrying out the invention]

[0011] Depending on their composition, metalworking fluids are classified as neat oils, soluble oils, semi-synthetic fluids, or synthetic fluids. Soluble oil MWFs contain 50-70% by weight of oil, with the remainder being wear-resistant / extreme pressure additives and emulsifiers. Semi-synthetic MWFs contain a significant amount, typically up to 50-60% by weight of water. Semi-synthetic fluids have a balanced lubrication and cooling performance, making them attractive for use as MWFs.

[0012] The present invention relates to a novel material that can be used as an antimicrobial agent for use in semi-synthetic metalworking fluids and such fluids. The substance of the present invention is an alkyl alcohol amine corresponding to the following formula (I).

[0013] [ka] In the formula, R1 and R2 are H or C2-C8 alkyl groups, provided that at least One of R1 and R2 is H, and at least one of R1 and R2 is a C2-C8 alkyl group. The C2-C8 alkyl group may be linear, branched, or cyclic, but linear is generally preferred.

[0014] Such alkylamine alcohol materials can be produced by the alkoxylation reaction of ammonia with an oxide (such as ethylene oxide, propylene oxide, or butylene oxide), as is generally known in the art.

[0015] The MWF of the present invention comprises water, one or more base oils, one or more organic acids, one or more emulsifiers, one or more lubricants, and one or more amines, wherein the amines function as pH adjusters and / or microbial growth regulators, and at least one amine comprises at least one alkylamine alcohol of formula (I).

[0016] The microbial growth control agent may further comprise one or more additional antimicrobial materials, such as glycol etheramines, which can be used in combination with the materials disclosed above to achieve specific microbial growth control objectives. The concentration of the microbial growth control agent / pH adjuster in the MWF (containing the alkylamine alcohol of formula (I)) may range from 1, 4, 6, 8, or 10 weight percent of the formulation to 30, 25, 15, or 12 weight percent of the formulation. Preferably, the alkylamine alcohol(s) of formula (I) may comprise 2, preferably 3, or even more than 5 weight percent of the MWF to 25, preferably 20, or even more than 15 weight percent.

[0017] The semi-synthetic MWF of the present invention also includes a base oil. The base oil may be any base oil generally known in the art for use in MWF. Preferably, the base oil is selected from tall oil, naphthenic oil, paraffinic oil, or ester oil, or a combination thereof. The concentration of the base oil(s) in the MWF may range from 5, 7, 10, or 15 weight percent of the composition to 50, 45, 40, or 35 weight percent of the composition.

[0018] The water used in these formulations is preferably deionized water and may contain at least 20, preferably 25, 30, or even 35 weight percent of the formulation, up to a maximum of 70, 65, 60, 55, or even 50 weight percent of the formulation. These formulations may be further diluted with additional water before use, and these ranges are intended to be modified accordingly. For example, before use, the formulation may be diluted so that the base oil concentration is 1 to 20 weight percent, more typically 5 to 7 weight percent, of the diluted formulation.

[0019] The semi-synthetic MWF of the present invention also contains one or more organic acids as solubilizers and / or corrosion inhibitors. Preferred organic acids include 2-ethylhexanoic acid, azelaic acid, tall oil fatty acids, 12-hydroxyl-(cis)-9-octadecenoic acid, dicarboxylic acid, and 9-octadecenoic acid. The concentration of the organic acid in the MWF may range from 2, 3, 4, or 5 weight percent of the composition to 12, 10, 8, or 7 weight percent of the composition.

[0020] The semi-synthetic MWF of the present invention also comprises one or more emulsifiers. The emulsifiers may be anionic, cationic, or nonionic. Examples of suitable anionic surfactants or emulsifiers are alkali metals, ammonium, and amine soaps. The fatty acid portion of such soaps preferably contains at least 10 carbon atoms. The soaps can also be formed in situ, in other words, by adding fatty acids to the oil phase and alkaline materials to the aqueous phase.

[0021] Other suitable anionic surfactants or emulsifiers include alkali metal salts of alkyl-aryl sulfonic acids, sodium dialkyl sulfosuccinate, sulfated or sulfonated oils, such as sulfated castor oil; sulfonated animal fats; and alkali salts of short-chain petroleum sulfonic acids.

[0022] Suitable cationic surfactants or emulsifiers include salts of long-chain primary, secondary, or tertiary amines, such as oleylamide acetate, acetylamine acetate, didodecylamine lactate, acetate of aminoethyl-aminoethyl stearamide, dilauroyltriethylenetetraminediacetate, and 1-aminoethyl-2-heptadecenylimidazoline acetate; as well as quaternary salts, such as cetylpyridinium bromide, hexadecylethylmorpholinium chloride, and diethyldidodecylammonium chloride.

[0023] Examples of suitable nonionic surfactants or emulsifiers include condensation products of higher fatty alcohols and ethylene oxide, e.g., reaction products of oleyl alcohol and 10 ethylene oxide units; condensation products of alkylphenols and ethylene oxide, e.g., reaction products of isooctylphenol and 12 ethylene oxide units; condensation products of higher fatty acid amides and 5 or more ethylene oxide units; polyethylene glycol esters of long-chain fatty acids such as tetraethylene glycol monopalmitate, hexaethylene glycol monolaurate, nonaethylene glycol monostearate, nonaethylene glycol dioleate, tridecaethylene glycol monoarachidate, tricosaethylene glycol monobehenate, and tricosaethylene glycol dibehenate; and polyhydric alcohol partial higher fatty acid esters such as sorbitan tristearate. These include ethylene oxide condensation products of polyhydric alcohol partial higher fatty acid esters and their intramolecular anhydrides (such as mannitol anhydride, also called mannitane; sorbitol anhydride, also called sorbitan), for example, glycerol monopalmitate reacted with 10 molecules of ethylene oxide, pentaerythritol monooleate reacted with 12 molecules of ethylene oxide, sorbitan monostearate reacted with 10-15 molecules of ethylene oxide, mannitane monopalmitate reacted with 10-15 molecules of ethylene oxide, etc.; and long-chain polyglycols in which one hydroxyl group is esterified with a higher fatty acid and the other hydroxyl group is etherified with a low molecular weight alcohol, such as methoxypolyethylene glycol 550 monostearate (where 550 means the average molecular weight of polyglycol ethers). Two or more combinations of these surfactants may be used; for example, cationic surfactants may be blended with nonionic surfactants, or anionic surfactants may be blended with nonionic surfactants.

[0024] Particularly suitable emulsifiers include ethoxylated or propoxylated C16-C18 alcohols; ethoxylated C12-C15 alcohols; sodium alkanesulfonates and alkyl ether carboxylates.

[0025] The concentration of the emulsifier(s) in the MWF may range from 4, 5, 6, 8, or 10 weight percent of the formulation to 25, 20, 15, or 12 weight percent of the formulation.

[0026] The semi-synthetic MWF of the present invention may also comprise one or more concentration additives. When present, preferred concentration additives include diethylene glycol butyl ether, ethylene glycol monobutyl ether, and propylene glycol butyl ether. When present, the concentration of the concentration additive(s) in the MWF may range from 0.3, 0.5, 1.0, or 1.5 weight percent of the formulation to 2.5, 2.0, or 1.8 weight percent of the formulation.

[0027] The semi-synthetic MWF of the present invention may also comprise other additives to provide additional functionality generally known in the art.

[0028] Microbial growth controlled by the biocide of the present disclosure typically consists of contaminants that are a mixture of bacteria and fungi. Some exemplary fungi and bacterial 5-containing species include, but are not limited to, Aeromonas hydrophila (ATCC 13444), Candida albicans (ATCC 752), Desulfovibrio desulfuricans (ATCC 7757), Escherichia coli (ATCC 8739), Flavobacterium ferrugineum (ATCC 13524), Fusarium oxysporum (ATCC 7601), Klebsiella pneumoniae (ATCC 13883), Proteus mirabilis (ATCC 4675), Pseudomonas aeruginosa (ATCC 8689), Pseudomonas oleovorans (ATCC 8062), and Saccharomyces cerevisiae 10 (ATTC 2338). The strains listed above may vary worldwide, and the present invention is fully contemplated as a broad-spectrum microbial growth control agent and / or biocide that can be used against any common MWF microbial contaminants.

Examples

[0029] Experiments for testing the effectiveness of formulations containing the microbial growth control agent of the present disclosure may be performed as follows. Table 1 contains a description of the materials used in these examples.

[0030]

Table 1

[0031] A series of formulations are prepared according to Table 2 using different amines listed in Table 3.

[0032]

Table 2

[0033] [Table 3]

[0034] The examples and comparative examples are obtained by diluting the concentrated formulation with water 20 times.

[0035] Prepare the concentrated formulation as follows: Pour the indicated amount of deionized water into a container. Add mineral oil, EcoSurf SA-7, Dowfax 20A42, secondary alkanesulfonate, tall oil acid, and diacitic acid (sebacic acid) to the water. Stir the formulation with a magnetic stirrer at 200 rpm and 60°C for 1 hour. Add the indicated amine as a pH adjuster.

[0036] Next, dilute the concentrated formulation 20-fold with process water or tap water (shown in Table 3) based on the total volume of the concentrated formulation. Test the pH value using a pH titrator (Mettler Toledo:#SevenMulti). If the pH value of the diluted formulation is below 9.5, add an additional 1-2 drops of monoethanolamine to raise the pH value to at least 9.5.

[0037] pH aging test: The pH values ​​of the prepared dilution formulation are tested at 0 and 14 days using a pH titrator (Mettler Toledo: #SevenMulti). The sample is left at room temperature.

[0038] [Table 4]

[0039] The pH decrease after two weeks of aging should be as small as possible. IE1 with monoisobutylamine, IE3 with a 2-amino-1-butanol / monoisobutanolamine mixture, and CE2 and CE3 with AMP-95 and dicyclohexylamine all exhibit similar levels of pH loss controlled within 5%. CE1 with monoisopropanolamine is not as good, as its pH loss exceeds 10%.

[0040] Aluminum corrosion test: Wash the aluminum flakes (#ADC12) with alcohol and weigh them. Immerse the aluminum flakes in the test solution at 40°C for 48 hours using a lidded vial (half the volume of the aluminum flakes is in the solution and the other half is exposed to air). Observe the corrosion of the aluminum flake surface, measure the weight loss of the aluminum flakes, and detect the aluminum content in the formulation using an ICP-OES (Inductively Coupled Plasma Emission Spectrometer: Perkin Elmer: #Optima 5300DV).

[0041] [Table 5]

[0042] The ICP-OES data shows agreement with qualitative observations of aluminum flake corrosion. Larger areas with yellow coloration indicate more severe corrosion and higher aluminum content in the test fluid. Qualitative descriptions such as "Pass," "Limited," or "Fail" are added to explain the observed results relatively. IE2 containing monoisobutylamine, IE4 containing a 2-amino-1-butanol / monoisobutanolamine mixture, and CE4 containing isomonopropanolamine and CE5 containing AMP-95 showed good corrosion resistance, with less than 1 ppm of aluminum leaching from the flakes. CE6 was worse than any of the other samples, with more than 2 ppm of aluminum leaching into the fluid.

[0043] Antimicrobial testing: The sample is handled according to the ASTM E 2275 method. This method can be summarized as follows: The inoculum is a mixture of ATCC strains of bacteria and fungi listed in Table 6. The emulsion product mixture inoculum is prepared by adding 0.1 mL of each bacterial overnight broth culture and 1.0 mL of each yeast broth culture to 10 mL of mold suspension and blending them together.

[0044] 0.5 mL of the mixed inoculum is administered to 50 grams of sample. This inoculation attacks emulsion samples containing high levels of microorganisms (10⁶–10⁷ colony-forming units per gram of sample, CFU / g). The attacked samples are mixed and stored in an incubator at 30°C for 7 days. This process is repeated five additional times, with the following amounts of inoculum added to each sample: 0.5 mL for the second test, 1.0 mL for the third, 1.0 mL for the fourth, and 3.0 mL for the fifth.

[0045] Microbial growth is monitored by culturing the inoculated emulsion sample on agar plates using the standard streak plate method. The sample is plate-cultured 1 day and 7 days after each microbial attack. The sample is blended by shaking, vortexing, or stirring using a sterile stick or sterile rod. The sample is uniformly streaked onto TSA and PDA plates, preferably using a standard 10 μL inoculation loop. The streaked agar plates are incubated at 30°C (TSA) and 25°C (PDA) for 7 days.

[0046] All agar plates are examined 7 days after inoculation to determine the number of surviving microorganisms in the test sample. For plates streaked 7 days after inoculation, colony growth is not considered acceptable.

[0047] [Table 6]

[0048] [Table 7] Passing = No colony proliferation Limit = Limit Colony Proliferation Failure = Significant colony proliferation

[0049] CE4 containing isomonopropanolamine fails in all tests. CE5 containing AMP-95 can pass the tests until the end of the week, but fails if it comes into contact with microorganisms for the first time on the first day of each test. IE2 containing monoisobutylamine and CE6 containing dicyclohexylamine show good antimicrobial performance, passing in all tests, whether on day 1 or day 7. IE4 containing a 2-amino-1-butanol / monoisobutanolamine mixture also passes the tests five times and shows good performance on day 7, but shows slightly worse performance on day 1 compared to IE2 and CE6.

[0050] A good amine pH adjuster must pass all three test items. Therefore, monoisobutylamine, 2-amino-1-butanol / monoisobutanolamine mixture, and AMP-95 are all eligible, but monoisobutylamine shows the best performance in terms of the three test results. Furthermore, although this application relates to the invention described in the claims, it may also encompass the following as other embodiments. (1) A semi-synthetic metalworking fluid, a. At least one base oil, b. A microbial growth control agent comprising an alkylamine alcohol having the following structure, [ka] In the formula, R 1 and R 2 is H, or a linear, branched, or cyclic alkyl group of C2-C8, however R 1 and R 2 At least one of them is H, and R 1 and R 2 At least one of them is a C2-C8 alkyl group; c. One or more organic acids, d. One or more emulsifiers, e. One or more concentrated additives, f. A semi-synthetic metalworking fluid containing water. [2] R of the microbial growth control agent 1 The semi-synthetic metalworking fluid described in [1] above, wherein H is present. [3]R 2 The semi-synthetic metalworking fluid described in [1] above, wherein is a linear alkyl group. [4] The semi-synthetic metalworking fluid according to [1] above, wherein the microbial growth control agent further comprises another amine. [5] The microbial growth control agent is the semi-synthetic metalworking fluid described in [1] above, comprising monoisobutyanolamine. [6] The semi-synthetic metalworking fluid described in [1] above, wherein the base oil is selected from naphthenic oil, paraffinic oil, ester oil, and mixtures thereof. [7] The emulsifier is selected from ethoxylated or propoxylated C16-C18 alcohols, ethoxylated C12-C15 alcohols, sodium alkanesulfonates, alkyl ether carboxylates, and mixtures thereof, as described in [1] above, a semi-synthetic metalworking fluid. [8] The solubilizer / corrosion inhibitor is selected from ethylhexanoic acid, azelaic acid, tall oil fatty acid, 12-hydroxyl-(cis)-9-octadecenoic acid, dicarboxylic acid, 9-octadecenoic acid, sebacic acid, and mixtures thereof, as described in [1] above. [9] The semi-synthetic metalworking fluid according to [1] above, wherein the microbial growth control agent is present in an amount of 6 to 15 weight percent of the semi-synthetic metalworking fluid.

[10] The semi-synthetic metalworking fluid according to [1] above, wherein the base oil is present in an amount of 10 to 45 weight percent of the semi-synthetic metalworking fluid.

[11] The semi-synthetic metalworking fluid according to [1] above, wherein the emulsifier is present in an amount of 5 to 20 weight percent of the semi-synthetic metalworking fluid.

[12] The semi-synthetic metalworking fluid according to [1] above, wherein the solubilizer is present in an amount of 3 to 10 weight percent of the semi-synthetic metalworking fluid.

[13] The semi-synthetic metalworking fluid according to [1] above, wherein the water is present in an amount of 20 to 60 weight percent of the semi-synthetic metalworking fluid.

[14] A composition suitable for use as a microbial growth control agent in a metalworking fluid containing an alkylamine alcohol having the following structure,

change

[15] R 1 and R 2 The composition according to

[14] above, wherein at least one of the members is a linear alkyl group.

Claims

1. A semi-synthetic metalworking fluid, a. At least one base oil and b. A microbial growth control agent comprising an alkylamine alcohol having the following structure, 【Chemistry 1】 In the formula, R １ and R ２ is H, or a linear, branched, or cyclic alkyl group of C2 to C8, however R １ and R ２ At least one of them is H, and R １ and R ２ At least one of them is a C2-C8 alkyl group; c. One or more organic acids, d. One or more emulsifiers, e. One or more concentrated additives, f. Water and, The microbial growth control agent is present in an amount of 5 to 25 weight percent of the semi-synthetic metalworking fluid. The organic acid is present in an amount of 2 to 12 weight percent of the semi-synthetic metalworking fluid. The emulsifier is present in an amount of 4 to 25 weight percent of the semi-synthetic metalworking fluid in the semi-synthetic metalworking fluid.

2. The R of the microbial growth control agent １ The semi-synthetic metalworking fluid according to claim 1, wherein H is present.

3. R ２ The semi-synthetic metalworking fluid according to claim 1, wherein is a linear alkyl group.

4. The semi-synthetic metalworking fluid according to claim 1, wherein the microbial growth control agent further comprises another amine.

5. The semi-synthetic metalworking fluid according to claim 1, wherein the microbial growth control agent comprises monoisobutanolamine.

6. The semi-synthetic metalworking fluid according to claim 1, wherein the base oil is selected from naphthenic oil, paraffinic oil, ester oil, and mixtures thereof.

7. The semi-synthetic metalworking fluid according to claim 1, wherein the emulsifier is selected from ethoxylated or propoxylated C16-18 alcohols, ethoxylated C12-C15 alcohols, sodium alkanesulfonates, alkyl ether carboxylates, and mixtures thereof.

8. The semi-synthetic metalworking fluid according to claim 1, wherein the organic acid used as a solubilizer / corrosion inhibitor is selected from ethylhexanoic acid, azelaic acid, tall oil fatty acid, 12-hydroxyl-(cis)-9-octadecenoic acid, dicarboxylic acid, 9-octadecenoic acid, sebacic acid, and mixtures thereof.

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

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

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

12. The semi-synthetic metalworking fluid according to claim 1, wherein the organic acid as a solubilizer is present in an amount of 3 to 10 weight percent of the semi-synthetic metalworking fluid.

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

14. The semi-synthetic metalworking fluid according to claim 1, wherein the concentration of the concentrated additive in the semi-synthetic metalworking fluid is 0.3 to 2.5 weight percent.

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