Aqueous semi-synthetic metalworking fluid compositions containing aminopropanediols

Abstract

The present invention describes an aqueous metalworking fluid comprising a base oil, an organic acid, optionally an emulsifier, an additive concentrate, water, and a microbial growth control agent comprising an aminopropanediol.

Description

[Technical field]

[0001] The present invention relates to a novel class of aminopropanediols.Embodiments relate to methods of controlling microbial growth in metalworking fluids that include adding such aminopropanediols to the metalworking fluid.Other embodiments relate to semi-synthetic metalworking fluid compositions that include a microbial growth control agent that includes this particular class of aminopropanediols. [Background technology]

[0002] Introduction Amines are widely used in a variety of applications due to their anti-corrosion, neutralizing, and pH adjusting properties. One common application of amines is in metalworking fluids. Metalworking fluids ("MWFs") are formulations with lubricating, cooling, and anti-corrosive properties and are used in metal manufacturing processes such as cutting, grinding, boring, turning, and drilling. Existing MWFs are typically classified as neat oil, soluble oil, semi-synthetic fluid, or synthetic fluid, with each category exhibiting different functions of cooling, lubricating, rust prevention, and cleaning. Commercially available MWFs may include oils, detergents, surfactants, lubricants, anti-corrosive agents, water, and other ingredients. Amine compositions are typically used to maintain an alkaline pH and neutralize acid-functional components in MWFs. Organic amines in MWFs, especially synthetic and semi-synthetic fluids, typically degrade over time due to microbial growth that adversely affects fluid performance as microorganisms feed on the active components in the fluid. Therefore, the MWF industry is looking for amine components that can maintain the pH value of the formulation and maintain performance over extended periods of time.

[0003] Such microbial growth in MWFs can cause serious problems in metalworking processing in many forms, including general souring of the MWF, changes in the viscosity of the MWF, shortening of the shelf life of the MWF, and corrosion of tools and materials. In addition, the functionality of equipment and processes such as delivery nozzles, storage tanks, pipelines, and recycling system equipment can also be affected by microbial growth in the MWF. This souring increases the cost of the MWF, accelerates the corrosion rate, and reduces the efficiency of metal processing. Thus, there is an unmet need in the MWF industry for components that do not support microbial growth and maintain performance over extended periods of time.

[0004] The most common solution is to add biocides and amine alcohols to a given MWF either continuously or as a batch process. However, biocides and some secondary amine alcohols are limited by regulatory restrictions. In biocide-containing MWFs, most of the biocide chemicals will release formaldehyde over time, which is harmful to human health.

[0005] Therefore, it would be desirable to have new semi-synthetic metalworking formulations with new biocidal compositions that provide improved cooling, lubricity, concentrate stability, and extended shelf life without the environmental health and safety concerns of current fluids.

[0006] The present invention addresses at least some of the needs set forth above. Summary of the Invention

[0007] The present invention relates to a novel class of aminopropanediols. The present invention relates to a method for controlling microbial growth in metalworking fluids, which method comprises the addition of at least one such aminopropanediol to the metalworking fluid. The present invention also describes an aqueous semi-synthetic metalworking fluid comprising a base oil, an organic acid, an emulsifier, an additive concentrate, water, and a microbial growth control agent comprising an aminopropanediol. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Depending on their composition, metalworking fluids are classified as neat oil, soluble oil, semi-synthetic fluids, or synthetic fluids. Soluble oil MWFs contain 50-70% oil by weight, the remainder being anti-wear / extreme pressure additives and emulsifiers. Semi-synthetic MWFs contain significant amounts of water, typically up to 50-60% by weight. Semi-synthetic fluids have balanced lubrication and cooling performance, making them attractive for use as MWFs.

[0009] The present invention relates to synthetic and / or semi-synthetic metalworking fluids, and novel materials that can be used as antimicrobial agents for use in such fluids. The novel antimicrobial agents of the present invention are aminopropanediols corresponding to the following formula (I):

[0010] [ka] In the formula, R1 is propane-2,3-diol, R2 is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol, and R3 is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol.

[0011] Such aminopropanediol materials can be produced by simple reaction between glycidol epoxide or 3-chloro-1,2-propanediol and ammonia, methylamine, or dimethylamine, and this type of reaction is generally known in the art. Useful aminopropanediol compounds include, but are not limited to, 3-aminopropane-1,2-diol, 3-(2-(hydroxyethyl)methylamino)propane-1,2-diol, 3-(methylamino)bis(propane-1,2-diol), 3-(amino)bis(propane-1,2-diol), 3-(amino)tris(propane-1,2-diol), 3-(methylamino)propane-1,2-diol, and mixtures thereof.

[0012] 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, one or more amines, where the amines function as pH adjusters and / or microbial growth control agents, and at least one amine comprises an aminopropanediol of formula (I).

[0013] The microbial growth control agent may further comprise one or more additional antimicrobial materials, such as glycol ether amines, which may be used in combination with the materials disclosed above to achieve a particular microbial growth control goal. The concentration of the microbial growth control agent / pH adjuster in the MWF (including the aminopropanediol of formula (I)) may range from 1, 4, 6, 8, or 10 percent by weight of the formulation to 30, 25, 15, or 12 percent by weight of the formulation. Preferably, the aminopropanediol of formula (I) comprises from 2, preferably 3, or even 5 percent by weight of the MWF to 25, preferably 20, or even 15 percent by weight.

[0014] The 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 MWFs. Preferably, the base oil is a base oil selected from tall oil, naphthenic oil, paraffinic oil, or ester oil, or combinations thereof. The concentration of the base oil in the MWF may range from 5, 7, 10, or 15 weight percent of the formulation to 50, 45, 40, or 35 percent of the formulation.

[0015] The water used in the present formulations is preferably deionized water and may comprise at least 20, preferably 25, 30, or even 35 weight percent of the formulation, up to 70, 65, 60, 55, or even 50 weight percent of the formulation. It is contemplated that these formulations may be further diluted with additional water prior to use, modifying these ranges accordingly. For example, prior to use, the formulations may be diluted such that the base oil concentration is 1 to 20 weight percent, more typically 5 to 7 weight percent of the diluted formulation.

[0016] The MWF of the present invention also includes one or more organic acids as solubilizers and / or corrosion inhibitors. Preferred organic acids include 2-ethylhexoic acid, azelaic acid, tall oil fatty acid, 12-hydroxyl-(cis)-9-octadecenoic acid, dicarboxylic acid, and 9-octadecenoic acid. The concentration of the organic acid in the MWF can range from 2, 3, 4, or 5 weight percent of the formulation to 12, 10, 8, or 7 percent of the formulation.

[0017] The MWF of the present invention may also optionally include one or more emulsifiers. The emulsifiers may be anionic, cationic, or nonionic. Examples of suitable anionic surfactants or emulsifiers are alkali metal, ammonium, and amine soaps. The fatty acid portion of such soaps preferably contains at least 10 carbon atoms. The soaps may also be formed "in situ", in other words, the fatty acid may be added to the oil phase and the alkaline material may be added to the water phase.

[0018] Other examples of suitable anionic surfactants or emulsifiers are alkali metal salts of alkyl-aryl sulfonic acids, sodium dialkyl sulfosuccinate, sulfated or sulfonated oils such as sulfated castor oil; sulfonated tallow, and alkali salts of short chain petroleum sulfonic acids.

[0019] Suitable cationic surfactants or emulsifiers are salts of long chain primary, secondary, or tertiary amines, such as oleylamide acetate, acetylamine acetate, di-dodecylamine lactate, acetate of aminoethyl-aminoethylstearamide, dilauroyltriethylenetetramine diacetate, 1-aminoethyl-2-heptadecenylimidazoline acetate; and quaternary salts, such as cetylpyridinium bromide, hexadecylethylmorpholinium chloride, and diethyldidodecylammonium chloride.

[0020] Examples of suitable nonionic surfactants or emulsifiers are condensation products of higher fatty alcohols with ethylene oxide, for example the reaction product of oleyl alcohol with 10 ethylene oxide units; condensation products of alkylphenols with ethylene oxide, for example the reaction product of isooctylphenol with 12 ethylene oxide units; condensation products of higher fatty acid amides with 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, tricosaethylene glycol dibehenate, and polyhydric alcohol moieties, such as sorbitan tristearate, and higher fatty acid esters. ethylene oxide condensation products of polyhydric alcohol partial higher fatty acid esters and their intramolecular anhydrides (called mannitol anhydride, mannitan, sorbitol anhydride, sorbitan), such as glycerol monopalmitate reacted with 10 molecules of ethylene oxide, pentaerythritol monooleate reacted with 12 molecules of ethylene oxide, sorbitan monostearate reacted with 10 to 15 molecules of ethylene oxide, mannitan monopalmitate reacted with 10 to 15 molecules of ethylene oxide, etc.; 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 (550 means the average molecular weight of the polyglycol ether). Combinations of two or more 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.

[0021] Particularly suitable emulsifiers include ethoxylated or propoxylated C16-18 alcohols; ethoxylated C12-C15 alcohols; sodium alkanesulfonates and alkyl ether carboxylates.

[0022] The concentration of the emulsifier in the MWF can range from 4, 5, 6, 8, or 10 weight percent of the formulation to 25, 20, 15, or 12 percent of the formulation.

[0023] The MWF of the present invention may also include one or more concentrated additives. When present, preferred concentrated additives include diethylene glycol butyl ether, ethylene glycol monobutyl ether, and propylene glycol butyl ether. When present, the concentration of concentrated additives 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 percent of the formulation.

[0024] The MWFs of the present invention may also include other additives to provide additional functionality as generally known in the art.

[0025] The microbial growth controlled by the biocides of the present disclosure typically consists of contaminants that are a mixture of bacteria and fungi. Some exemplary fungal and bacterial5 inclusions 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 cerevisiae10 (ATTC 2338). The strains listed above may vary worldwide and the present invention is fully envisioned as a broad spectrum microbial growth control agent and / or biocide that can be used against any common MWF microbial contaminant. EXAMPLES

[0026] Experiments to test the effectiveness of formulations containing the microbial growth control agents of the present disclosure can be performed as follows: Table 1 contains a description of the materials used in these examples.

[0027] [Table 1]

[0028] A series of formulations are prepared according to Table 2 using different amines as listed in Table 3.

[0029] [Table 2]

[0030] [Table 3]

[0031] Concentrated formulations are prepared as follows: Pour the indicated amount of deionized water into a container. Add mineral oil, EcoSurf SA-7, Dowfax 20A42, secondary alkane sulfonate, tall oil acid, and diacid (sebacic acid) to the water. Stir the formulation with a magnetic stirrer at 200 rpm at 60° C. for 1 hour. Add the indicated amine as a pH adjuster.

[0032] The concentrated formulation is then diluted 20 times based on the total volume of the concentrated formulation by processing. The pH value is tested by a pH titrator (Mettler Toledo: #SevenMulti). If the pH value of the diluted formulation is below 9.5, additional monoethanolamine (1-2 drops) is introduced to increase the pH value to at least 9.5.

[0033] pH aging test: The pH values ​​of the prepared diluted formulations are tested at 0 days and 14 days by a pH titrator (Mettler Toledo: #SevenMulti). The samples are placed at room temperature.

[0034] [Table 4]

[0035] The pH loss after 2 weeks of aging should be as small as possible. IE1 with methylaminopropanediol and IE2 with dimethylaminopropanediol show limited pH loss (<3%). CE1 with monoisopropanolamine is not as good in that the pH loss exceeds 10%.

Claims

1. 1. A metalworking fluid comprising: a. at least one base oil; b. at least one microbial growth control agent comprising an aminopropanediol having a structure corresponding to the following formula: 【Chemistry 1】 In the formula, R １ is propane-2,3-diol, R ２ is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol; R ３ is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol; and c. one or more organic acids; d. optionally, one or more emulsifiers; e. one or more additive concentrates; f. Water.

2. R of the microbial growth control agent ２ and R ３ 10. The metalworking fluid of claim 1 , wherein at least one of is methyl.

3. R of the microbial growth control agent ２ and R ３ 10. The metalworking fluid of claim 1 , wherein both of are methyl.

4. The metalworking fluid of claim 1 , wherein the microbial growth control agent further comprises another amine.

5. 10. The metalworking fluid of claim 1, wherein the base oil is selected from naphthenic oils, paraffinic oils, ester oils, and mixtures thereof.

6. 2. The metalworking fluid of claim 1, wherein the emulsifier is selected from ethoxylated or propoxylated C16-18 alcohols, ethoxylated C12-C15 alcohols, sodium alkanesulfonates, and alkyl ether carboxylates, and mixtures thereof.

7. 2. The metalworking fluid of claim 1, wherein 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.

8. 2. The metalworking fluid of claim 1, wherein the additive concentrate is selected from diethylene glycol butyl ether, ethylene glycol monobutyl ether, propylene glycol butyl ether, and mixtures thereof.

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

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

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

12. The metalworking fluid of claim 1 , wherein the solubilizing agent is present in an amount of 3 to 10 weight percent of the metalworking fluid.

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

14. 1. A composition suitable for use as a microbial growth control agent in metalworking fluids comprising an aminopropanediol having a structure corresponding to the formula: 【Chemistry 2】 In the formula, R １ is propane-2,3-diol, R ２ is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol; R ３ is hydrogen, methyl, ethyl, 2-hydroxyethyl, or propane-2,3-diol.

15.

15. R of the composition ２ and R ３ 15. The metalworking fluid of claim 14, wherein at least one of is methyl.

16. R of the composition ２ and R ３ 16. The metalworking fluid of claim 15, wherein both of are methyl.

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