KR20230141197A - Eco-friendly water-soluble cutting oil composition - Google Patents

Abstract

The present invention produces water-soluble cutting oil by mixing a slightly alkaline rust-prevention additive, lubricity improver, and discoloration inhibitor in a solvent, thereby preventing oxidation from the metal surface deep inside the metal surface due to the cobalt elution that occurs during carbide grinding, as conventional cutting oil does. There is a problem of shortening the service life of the machined parts due to the formation of a film, whereas in the case of the present invention, cobalt elution that occurs during carbide grinding is suppressed and adhesive residue (Residue-Adhesion) does not form or stick to the grinding stone. It has excellent chip separation properties, extending the service life of grinding tools, and has the advantage of maintaining excellent rust prevention properties as well as surface discoloration and rusting.

Description

Eco-friendly water-soluble cutting oil composition {Eco-friendly water-soluble cutting oil composition}

The present invention relates to a composition of eco-friendly water-soluble cutting oil. More specifically, by mixing environmentally friendly slightly alkaline substances in a solvent to produce water-soluble cutting oil, cobalt elution occurring during carbide grinding can be suppressed, making it possible to use grinding tools. It relates to a composition of an eco-friendly water-soluble cutting oil, which is capable of preventing discoloration or etching that occurs on parts or painted surfaces of cutting machines and non-ferrous metals by extending the life of the product and suppressing surface discoloration or rusting in a high-temperature and high-humidity environment. .

In general, cutting oil is divided into emulsion type cutting oil containing lubricating base oil, semi-synthetic type cutting oil containing vegetable oil, synthetic substances, and surfactants, and synthetic type cutting oil. When manufactured, the cutting oil easily rots and deteriorates, causing bad odors and a bad working environment during work, and contaminating the machine, making it difficult to clean the workpiece. And semi-synthetic water-soluble cutting-induced rot, which consists of vegetable oil and synthetic-based surfactant system, cannot be prevented. In addition, the synthetic type has excellent decay resistance, but has the disadvantage of being poor in lubrication, pressure resistance, and machinability.

However, the above disadvantages can be overcome by adding a phosphoric acid ester compound that supplements lubricity and cools by dispersing the pressure applied to the cutting tool and workpiece, but this also has the problem of creating a harmful situation due to a chemical reaction with other added compounds. It can be caused.

Meanwhile, looking at patent applications filed through research and development of water-soluble cutting oil as a way to solve the problems of cutting oil as described above, in Patent Registration No. 10-2250202, distilled water; Butanol amine, propanol amine mixture; octanolamine; Synthetic ester mixture of tricarboxylic acid; fatty acid; polyalkylene glycol alkyl ether; paraffin refined oil; An eco-friendly water-soluble cutting oil composition is known, characterized by containing an antiseptic preservative; alkyloxy polyethylene oxyethanol; however, in the case of this composition, the function of suppressing metal oxidation can be further improved by using an amine material. There are problems such as damaging the painted surface or etching by infringing on the magnetic table that holds the object to be erased, and causing significant pollution when disposing of wastewater.

And in Registration Patent No. 10-2339991, 1 to 50% by weight of lubricating additive; 1 to 40% by weight of lubricity improver; and 0.01 to 10% by weight of a rust preventive additive, wherein the rust preventive additive is selected from the group consisting of one or more branched fatty acids having 2 to 30 carbon atoms, dibasic acids having 2 to 30 carbon atoms, and tribasic acids having 2 to 30 carbon atoms. It includes at least one selected, and the lubricant additive includes a polyalkylene glycol-based copolymer, and the polyalkylene glycol-based copolymer is two or more types of EO different from each other in molecular weight and EO block content of the EO/PO copolymer. /PO copolymer; and a water-soluble cutting oil composition further comprising 5% to 40% by weight of a pH adjuster. However, in the case of this composition, a basic substance is added to the mixture of cutting oil, making it difficult to process non-ferrous metals. In some cases, there is a problem that causes etching or discoloration.

As a solution to the above problems, the present invention produces water-soluble cutting oil by mixing a solvent with a rust-prevention additive, a lubricity improver, and a discoloration prevention agent made of a weakly alkaline material, thereby suppressing cobalt elution that occurs during carbide grinding. It extends the service life of grinding tools by preventing surface discoloration or rusting in a high-temperature and high-humidity environment as well as rust occurring in machined machine parts by suppressing discoloration or etching of non-ferrous metals with excellent rust prevention. The aim is to provide a composition of an eco-friendly water-soluble cutting oil that is capable of doing so.

The present invention to solve the above problems includes 20 to 30 parts by weight of a rust preventive additive, 15 to 25 parts by weight of a lubricity improver, 15 to 25 parts by weight of an anti-discoloration agent, 10 to 20 parts by weight of an antioxidant, and an emulsion stabilizer, based on 100 parts by weight of the solvent. Containing 5 to 10 parts by weight is considered a means of solving the problem.

In the above, the rust preventive additive is characterized in that it contains 20 to 30 parts by weight of an amine-based rust preventive additive and 70 to 80 parts by weight of peroxide out of a total of 100 parts by weight, and the discoloration inhibitor is a cationic surfactant or a non-ionic interface agent out of a total of 100 parts by weight. It is characterized in that it contains 40 to 50 parts by weight of an activator and 50 to 60 parts by weight of dioic acid, and the antioxidant includes 40 to 50 parts by weight of a ferrous metal antioxidant and 50 to 60 parts by weight of a non-ferrous metal antioxidant out of a total of 100 parts by weight. It is characterized by

And the iron metal antioxidant is characterized in that it contains 40 to 50 parts by weight of aminomethylphosphonic acid, 40 to 50 parts by weight of polycarboxylic acid, and 10 to 20 parts by weight of peracetic acid out of a total of 100 parts by weight.

The composition of the eco-friendly water-soluble cutting oil according to the present invention as a means of solving the above problem produces water-soluble cutting oil by mixing a solvent with a rust preventive additive, a lubricity improver, a discoloration inhibitor, an antioxidant, etc. composed of a weakly alkaline material, so that the conventional cutting oil is used for carbide grinding. There is a problem of shortening the service life of the machined parts due to the formation of an oxide film from the metal surface to deep inside due to cobalt elution occurring during processing. However, in the case of the present invention, cobalt elution occurring during carbide grinding is suppressed. It has excellent chip separation properties that prevent sticky residue from forming or sticking to the grinding stone, thereby extending the service life of the grinding tool. In addition, it has excellent rust prevention properties as well as surface discoloration and rusting in high-temperature and high-humidity environments. It has the advantage of preventing rust from occurring in processed machine parts or non-ferrous metals by suppressing discoloration or etching of non-ferrous metals.

The present invention to achieve the above effects relates to a composition of eco-friendly water-soluble cutting oil, and only the parts necessary to understand the present invention will be described, and the description of other parts will be omitted to the extent that it does not distract from the gist of the present invention. You should take note of this.

The present invention contains 20 to 30 parts by weight of a rust prevention additive, 15 to 25 parts by weight of a lubricity improver, 15 to 25 parts by weight of an anti-discoloration agent, 10 to 20 parts by weight of an antioxidant, and 5 to 10 parts by weight of an emulsion stabilizer, based on 100 parts by weight of the solvent. It is characterized by

In the present invention, the solvent serves to uniformly dilute the added mixture, and is not particularly limited, but a preferred solvent may be one or more selected from pure water, ultrapure water, and distilled water.

In the present invention, the rust preventive additive serves to prevent rust by adsorbing to the surface during carbide grinding and suppressing cobalt elution that occurs during processing. The amount used is 20 to 30 parts by weight per 100 parts by weight of solvent. Suitable. If the mixing amount of the rust preventive additive is less than 20 parts by weight, there is a risk of rust occurring due to a decrease in surface adsorption during carbide grinding due to a decrease in the mixing amount of the rust preventive additive. If the mixing amount of the rust preventive additive exceeds 30 parts by weight, the mixing amount of the rust preventive additive may be reduced. Excessive use of carbide can prevent rust by improving the surface adsorption during grinding, but there is a risk that the inherent function of the cutting oil may be deteriorated due to a decrease in the mixing amount of other additives.

And, the rust preventive additive used in the present invention is preferably used in a mixture of 20 to 30 parts by weight of amine-based rust preventive additive and 70 to 80 parts by weight of peroxide out of a total of 100 parts by weight.

In the above, the amine-based rust prevention additive is not particularly limited, but is preferably a diphenylamine-based additive such as diphenylamine, monooctyldiphenylamine, monononyldiphenylamine, 4,4'-dibutyldiphenylamine, 4,4. '-dihexyldiphenylamine, 4,4'-dioctyldiphenylamine, 4,4'-dinonyldiphenylamine, tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine , Naphthylamine series include α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, hexylphenyl-α-naphthylamine, octylphenyl-α-naphthylamine, nonylphenyl- It is appropriate to select and use one or more types of α-naphthylamine.

In the above, the peroxide is preferably selected from one or more of hydrogen peroxide, sodium metasilicate, sodium gluconate, nickel chloride, and mixtures thereof.

In the present invention, the lubricity improver provides lubricity to the grinding tool to maintain smooth properties during grinding of parts, prevents sticky residue from forming or sticking to the grinding stone, extends the service life of the grinding tool, and provides wetting power to the mixture. As a result, it is appropriate to mix 15 to 25 parts by weight with respect to 100 parts by weight of the solvent. If the mixing amount of the lubricity improver is less than 15 parts by weight, the lubricity may decrease and the lifespan of the grinding tool for grinding the parts may be reduced. If the mixing amount of the lubricity improver exceeds 25 parts by weight, the lubricity will be further improved and the grinding tool The usable life can be extended, but the effect is weak compared to the amount used.

And the lubricity improver is a polyfunctional alcohol such as ethylene glycol, propylene glycol, methyl propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, hexylene glycol, and neo. Pentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, trimethylpentanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, triethylene glycol, cyclohexanedimethanol, bisphenol A, glycerin, trime It is suitable to use one or more of tyrolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, ribitol, sorbi, and mannitol.

In the present invention, the anti-discoloration agent serves to prevent surface discoloration of processed parts that occurs due to chemical or physical phenomena due to the high temperature and humidity of the workshop environment when grinding carbide. The amount used is per 100 parts by weight of solvent. It is appropriate to mix 15 to 25 parts by weight. If the mixing amount of the anti-discoloration agent is less than 15 parts by weight, difficulties are expected in preventing surface discoloration of parts that occur at the work site due to insufficient mixing amount of the anti-discoloration agent, and if the mixing amount of the anti-discoloration agent exceeds 25 parts by weight, the anti-discoloration agent is expected to be difficult to prevent. Excessive mixing amount can prevent surface discoloration of processed parts that occurs at work sites, but the effect is weak compared to the amount used.

And the anti-discoloration agent used in the present invention is preferably used in a mixture of 40 to 50 parts by weight of a cationic surfactant or nonionic surfactant and 50 to 60 parts by weight of dioic acid out of a total of 100 parts by weight.

In the above, it is preferable to use one type of cationic surfactant selected from saturated or unsaturated fatty acids such as oleic acid, lauric acid, dodecylic acid, and dodecanoic acid.

In the above, the nonionic surfactant is sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, propyl polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerin fatty acid ester. It is preferable to select and use one or more of polyoxyethylene propylene glycol fatty acid ester, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

In the above, the diioic acid is ethanedioic acid, propanedioic acid, butanedioic acid, pentanedioic acid, hexanedioic acid, octanedioic acid, nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, and hexadecanedioic acid. It is desirable to select and use one or more types from Iksan.

Meanwhile, the surfactant is more preferably used in a mixture of 50 to 60 parts by weight of a cationic surfactant and 40 to 50 parts by weight of a nonionic surfactant out of a total of 100 parts by weight.

In the present invention, the antioxidant is added to prevent the auto-oxidation phenomenon that occurs in grinding parts due to the action of oxygen, and the appropriate amount of the antioxidant is mixed in 10 to 20 parts by weight per 100 parts by weight of solvent. If the mixing amount of the antioxidant is less than 10 parts by weight, it is difficult to prevent auto-oxidation that occurs in grinded parts due to a decrease in the mixing amount of the antioxidant, and if the mixing amount of the antioxidant exceeds 20 parts by weight, the amount of antioxidant is reduced. Auto-oxidation phenomenon that occurs in parts grinded with excessive mixing amount can be prevented, but the effect is weak compared to the amount used.

And the antioxidant used in the present invention includes 40 to 50 parts by weight of a ferrous metal antioxidant and 50 to 60 parts by weight of a non-ferrous metal antioxidant out of a total of 100 parts by weight.

Meanwhile, the iron metal antioxidant used above is preferably used by mixing 40 to 50 parts by weight of aminomethylphosphonic acid, 40 to 50 parts by weight of polycarboxylic acid, and 10 to 20 parts by weight of peracetic acid, out of a total of 100 parts by weight. is most suitable.

In the above, aminomethylphosphonic acid is 2-hydroxyethylaminobismethylphosphonic acid, iso-propylaminobismethylphosphonic acid, n-propylaminobismethylphosphonic acid, n-butylaminobismethylphosphonic acid, and n-hexylaminobis. Methylphosphonic acid, 2-ethylhexylaminobismethylphosphonic acid, n-octylaminobismethylphosphonic acid, iso-nonylaminobismethylphosphonic acid, dodecylaminobismethylphosphonic acid, diethylaminomethylphosphonic acid, diethylamino It is preferable to select and use one or more of dimethylphosphonic acid, dimethylaminomethylphosphonic acid, and dimethylaminodimethylphosphonic acid.

In the above, the polycarboxylic acid is preferably selected from one or more of succinic acid, dimethylsuccinic acid, alkylsuccinic acid, alkenylsuccinic acid, adipic acid, and citric acid.

And the antioxidants for non-ferrous metals used in the present invention are benzotriazole, 5-aminobenzotriazole, 1-hydroxybenzotriazole, 5-phenylthiol-benzotriazole, 5-chlorobenzotriazole, and 4-chlorobenzo. Triazole, 5-bromobenzotriazole, 4-bromobenzotriazole, 5-fluorobenzotriazole, 4-fluorobenzotriazole, naphthotriazole, tolyltriazole, 5-phenyl-benzotriazole Sol, 5-nitrobenzotriazole, 4-nitrobenzotriazole, 2-(5-amino-pentyl)-benzotriazole, 1-amino-benzotriazole, 5-methyl-1H-benzotriazole, benzotriazole Sol-5-carboxylic acid, 4-methylbenzotriazole, 4-ethylbenzotriazole, 5-ethylbenzotriazole, 4-propylbenzotriazole, 5-propylbenzotriazole, 4-isopropylbenzotriazole , 5-isopropylbenzotriazole, 4-n-butylbenzotriazole, 5-n-butylbenzotriazole, 4-isobutylbenzotriazole, 5-isobutylbenzotriazole, 4-pentylbenzotriazole, 5-pentylbenzotriazole, 4-hexylbenzotriazole, 5-hexylbenzotriazole, 5-methoxybenzotriazole, 5-hydroxybenzotriazole, dihydroxypropylbenzotriazole, 1-[N, N-bis(2-ethylhexyl)aminomethyl]-benzotriazole, 5-t-butylbenzotriazole, 5-(1',1'-dimethylpropyl)-benzotriazole, 5-(1', One or more of 1',3'-trimethylbutyl)benzotriazole, 5-n-octylbenzotriazole, and 5-(1',1',3',3'-tetramethylbutyl)benzotriazole It is desirable to select and use .

In the present invention, the emulsion stabilizer serves to improve the emulsibility of the emulsion produced in water-soluble cutting oil, and the appropriate amount of use is 5 to 10 parts by weight per 100 parts by weight of solvent. If the mixing amount of the emulsion stabilizer is less than 5 parts by weight, there is a risk that the emulsibility of the emulsion may decrease, and if the mixing amount of the emulsion stabilizer exceeds 10 parts by weight, the emulsibility of the emulsion may be improved, but compared to the mixing amount. The effect is weak.

The emulsion stabilizer is not particularly limited, but is preferably selected from one or more of guar gum, gum arabic, tracantham gum, karaya gum, gellan gum, lamic acid gum, whelan gum, xanthan gum, and carbomer. It is appropriate to do so.

Meanwhile, the eco-friendly water-soluble cutting oil manufactured using the above composition is manufactured by mixing a solvent with a rust-prevention additive, a lubricity improver, a discoloration inhibitor, an antioxidant, etc. composed of weakly alkaline substances, thereby suppressing the elution of cobalt that occurs during carbide grinding. It prevents adhesive residue from forming or sticking to the grinding stone, thereby extending the service life of the grinding tool. It also prevents surface discoloration and rusting that occurs in high-temperature and humid environments, as well as excellent rust prevention and discoloration and etching. The advantage is that it can prevent rust occurring in machine parts or non-ferrous metals.

Hereinafter, the configuration of the present invention will be described in detail through examples as follows, and the configuration of the present invention is not necessarily limited to the following examples.

1. Preparation of water-soluble cutting oil

(Example 1)

Water-soluble cutting oil was prepared by adding 600 g of rust prevention additive, 600 g of hexylene glycol, 450 g of discoloration inhibitor, 450 g of antioxidant, and 300 g of guar gum to 3 liters of pure water.

In the above, the rust prevention additive was a mixture of 360g of diphenylamine and 240g of hydrogen peroxide, the discoloration inhibitor was a mixture of 250g of dodecanoic acid and 200g of hexanedioic acid as a cationic surfactant, and the antioxidant was diethylamino as an iron metal oxidation antioxidant. 110 g of methylphosphonic acid, 100 g of dimethyl succinic acid, 60 g of peracetic acid, and 180 g of benzotriazole as a non-ferrous metal antioxidant were mixed.

(Example 2)

Water-soluble cutting oil was prepared by adding 750 g of rust prevention additive, 450 g of hexylene glycol, 600 g of discoloration inhibitor, 600 g of antioxidant, and 150 g of guar gum to 3 liters of pure water.

In the above, the rust prevention additive is a mixture of 450g of diphenylamine and 300g of hydrogen peroxide, the discoloration inhibitor is a mixture of 300g of dodecanoic acid as a cationic surfactant and 300g of hexanedioic acid as a diioic acid, and the antioxidant is diethyl as an iron metal antioxidant. 150g of aminomethylphosphonic acid, 130g of dimethylsuccinic acid, 80g of peracetic acid, and 240g of benzotriazole as a non-ferrous metal antioxidant were mixed.

(Comparative Example 1)

Manufactured by domestic company A, it is a water-soluble cutting oil W3 type 1, a KS-approved product.

(Comparative Example 2)

Manufactured by domestic company B, it is water-soluble cutting oil W3 type 1, a KS-approved product.

2. Evaluation method

According to the KS M 2525 cutting fluid test method, appearance, surface tension, non-volatile matter, pH, sulfur content, bubble test, and metal corrosion were measured three times each, and the average results of the measured values are shown in [Table 1].

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Exterior Transparency Transparency Transparency Transparency Transparency Surface tension (10-3 N/m) over 40 72.4 75.5 43.8 46.6 Non-volatile content (%) over 80 91.8 93.4 84.2 83.4 pH More than 8.5 but less than 10.5 9.1 9.2 8.6 10.2 Sulfur content (%) 5 or less 1.58 1.47 3.69 4.02 Bubble test mL(24±2)℃ 1 or less 0.34 0.32 0.76 0.69 Metal corrosion (room temperature, 24h) There will be no discoloration
(steel plate) No discoloration No discoloration No discoloration No discoloration

According to [Table 1], in the case of Examples 1 and 2, water-soluble cutting oil was prepared by adding mixtures consisting of weakly alkaline substances specified in the present invention within the range, thereby improving surface tension, non-volatility, and pH. The properties such as these are very excellent compared to the standard value, extending the life of the grinding tool, and have the advantage of maintaining excellent rust prevention as well as surface discoloration and rusting. However, in the case of Comparative Examples 1 and 2, surface tension, non-volatility, and pH Since the properties such as these are close to the standard values, it is possible to maintain the inherent function of water-soluble cutting oil, but it was evaluated that it is difficult to extend the life of the grinding tool and prevent surface discoloration, etc., as in Examples 1 and 2.

As described above, the composition of the eco-friendly water-soluble cutting oil according to the present invention has been explained through the above preferred embodiments and its excellence has been confirmed, but those skilled in the art will be able to understand the spirit and scope of the present invention as set forth in the patent claims below. It will be understood that various modifications and changes can be made to the present invention without departing from the scope.

Claims (7)

Characterized in that it contains 20 to 30 parts by weight of a rust prevention additive, 15 to 25 parts by weight of a lubricity improver, 15 to 25 parts by weight of a discoloration inhibitor, 10 to 20 parts by weight of an antioxidant, and 5 to 10 parts by weight of an emulsion stabilizer, based on 100 parts by weight of the solvent. A composition of eco-friendly water-soluble cutting oil. According to paragraph 1,
A composition of an eco-friendly water-soluble cutting fluid, wherein the rust preventive additive includes 20 to 30 parts by weight of an amine-based rust preventive additive and 70 to 80 parts by weight of peroxide out of a total of 100 parts by weight. According to paragraph 1,
The lubricant improver includes ethylene glycol, propylene glycol, methyl propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, hexylene glycol, neopentyl glycol, 2- Butyl-2-ethyl-1,3-propanediol, trimethylpentanediol, diethylene glycol, dipropylene glycol, trimethylene glycol, triethylene glycol, cyclohexanedimethanol, bisphenol A, glycerin, trimethylolethane, trimethane A composition of eco-friendly water-soluble cutting oil, characterized in that one or more of tyrol propane, pentaerythritol, dipentaerythritol, ribitol, sorbi, and mannitol is used. According to paragraph 1,
A composition of an eco-friendly water-soluble cutting oil, wherein the anti-discoloration agent includes 40 to 50 parts by weight of a cationic surfactant or nonionic surfactant and 50 to 60 parts by weight of dioic acid out of a total of 100 parts by weight. According to paragraph 1,
A composition of an eco-friendly water-soluble cutting oil, wherein the antioxidant comprises 40 to 50 parts by weight of a ferrous metal antioxidant and 50 to 60 parts by weight of a non-ferrous metal antioxidant out of a total of 100 parts by weight. According to clause 5,
A composition of an eco-friendly water-soluble cutting oil, wherein the iron metal antioxidant comprises 40 to 50 parts by weight of aminomethylphosphonic acid, 40 to 50 parts by weight of polycarboxylic acid, and 10 to 20 parts by weight of peroxyacetic acid out of a total of 100 parts by weight. According to clause 5,
The non-ferrous metal antioxidants include benzotriazole, 5-aminobenzotriazole, 1-hydroxybenzotriazole, 5-phenylthiol-benzotriazole, 5-chlorobenzotriazole, 4-chlorobenzotriazole, and 5-bro. Mobenzotriazole, 4-bromobenzotriazole, 5-fluorobenzotriazole, 4-fluorobenzotriazole, naphthotriazole, tolyltriazole, 5-phenyl-benzotriazole, 5-nitrobenzo Triazole, 4-nitrobenzotriazole, 2-(5-amino-pentyl)-benzotriazole, 1-amino-benzotriazole, 5-methyl-1H-benzotriazole, benzotriazole-5-carboxyl Acid, 4-methylbenzotriazole, 4-ethylbenzotriazole, 5-ethylbenzotriazole, 4-propylbenzotriazole, 5-propylbenzotriazole, 4-isopropylbenzotriazole, 5-isopropylbenzo Triazole, 4-n-butylbenzotriazole, 5-n-butylbenzotriazole, 4-isobutylbenzotriazole, 5-isobutylbenzotriazole, 4-pentylbenzotriazole, 5-pentylbenzotriazole , 4-hexylbenzotriazole, 5-hexylbenzotriazole, 5-methoxybenzotriazole, 5-hydroxybenzotriazole, dihydroxypropylbenzotriazole, 1-[N,N-bis(2- Ethylhexyl)aminomethyl]-benzotriazole, 5-t-butylbenzotriazole, 5-(1',1'-dimethylpropyl)-benzotriazole, 5-(1',1',3'- Use one or more of trimethylbutyl)benzotriazole, 5-n-octylbenzotriazole, and 5-(1',1',3',3'-tetramethylbutyl)benzotriazole. A composition of eco-friendly water-soluble cutting oil characterized by: