JP5841445B2 - Water-soluble metalworking fluid composition, coolant, use of amine compound as gas-phase fungicide, gas-phase fungicide method, and metal-working method - Google Patents

Description

  The present invention relates to a water-soluble metalworking fluid composition used in metalworking such as cutting, grinding, and plastic working.

  When performing metal processing such as cutting, grinding, and plastic processing, a processing oil is used to lubricate and cool between the processing tool and the workpiece. The processing fluids include oil-based processing fluids and water-soluble processing fluids, but water-soluble processing fluids are mainly used because they can be efficiently cooled and fires can be prevented even during unmanned machines. It has been. During metal processing, a large amount of processing oil is used while being circulated by a pump.

  Water-soluble processing oils used in metal processing generally include mineral oils, fats and oils, fatty acids, fatty acid esters, extreme pressure additives, surfactants, antifoaming agents, metal anticorrosives, antioxidants, antiseptic and antifungal agents, etc. It is manufactured by mixing as appropriate according to the purpose, diluted with water and used as a so-called coolant. The coolant is required to have primary performance related to machinability, grindability and the like, and secondary performance related to workability and the like. Examples of the primary performance include improvement of finished surface accuracy, extension of the tool life, etc. Examples of the secondary performance include excellent rust prevention, easy deterioration and easy management, It is innocuous and has less foaming.

  Since the water-soluble processing oil contains a large amount of substances that serve as nutrient sources for microorganisms such as bacteria, yeast, and mold as described above, there is a problem that the diluted coolant is likely to spoil. As the decay of the coolant progresses, both the primary performance and the secondary performance are deteriorated, and a bad odor due to decay becomes a problem. In addition, if the frequency of oil replacement becomes high due to decay, it is disadvantageous in terms of cost. Further, when mold occurs in the coolant, it may cause clogging of pipes in a circulation system such as a pump. In order to prevent this, an antiseptic / antifungal agent is added to the processing oil, or an antiseptic / antifungal treatment is performed with other components.

  However, in general, antiseptics and fungicides have a problem that their effects are significantly reduced in a short period of time due to decomposition or inactivation. In addition, as widely known antiseptics and fungicides, there are formaldehyde releasing type and phenol type, and these are stimulants. That is, when added in a large amount to the extent that the processing oil can exhibit antiseptic and antifungal performance, the processing oil itself becomes extremely irritating to the skin, which may adversely affect the human body.

  Moreover, in processing oil agent, there exists what uses the amine soap which made the fatty acid and various amines react as surfactant (emulsifier) (patent document 1). In this case, the processing oil agent is present in a state in which an alkali amine is liberated, and a certain amount of antiseptic and antifungal properties can be imparted to the processing oil agent by containing a large amount of the amine in the free state. There is also a technique of including an antibacterial amine in a processing oil (Patent Document 2).

Japanese Examined Patent Publication No. 61-40720 JP 2009-161585 A

  As described above, in the prior art, only metalworking fluid compositions and coolants have been focused on antiseptic and mildewproofing in the liquid phase.

  On the other hand, the causes of clogging of piping and screens in factories and plants where water-soluble metalworking fluids are used are often derived from mold that propagates in the gas phase from the gas-liquid interface in the tank. In the above-described prior art, only the growth of mold in the liquid phase is suppressed or killed, and the growth of mold in the gas phase cannot be suppressed. Conventionally, in order to prevent the growth of mold in the gas phase, there was no means other than temporarily removing the mold in the gas phase by physical cleaning or the like.

  However, even if mold in the gas phase is temporarily removed by physical cleaning, etc., if mold mycelium or spores remain even a little, mold grows in a short period of time, and this may come off. In piping, screens, and other plant equipment, there was a problem of repeated troubles such as blockage and overflow.

  In view of the above problems, an object of the present invention is to provide a water-soluble metalworking fluid composition capable of suppressing the growth of mold in the gas phase.

  As a result of intensive research aimed at a water-soluble metalworking fluid composition capable of effectively suppressing mold growth in the gas phase, the present inventors added a predetermined amine to the water-soluble metalworking fluid composition. In addition, by setting the pH at the time of use to a predetermined value or more, growth of mold in the gas phase can be inhibited, and various troubles of the plant originating from mold growing in the gas phase from the gas-liquid interface in the liquid tank. I found that it can be avoided.

The present invention has been made based on the above findings. That is,
The first aspect of the present invention contains an amine compound having a linear, branched or cyclic saturated hydrocarbon group having 4 or more carbon atoms, and the pH at the time of use is ½ equivalent of the amine compound. It is a water-soluble metalworking fluid composition that does not fall below the pH neutralized with acid by 1 or more.

In the present invention, as the amine compound, it is preferable to use a compound having a vapor pressure at 25 ° C. of 0.0075 mmHg or more or a Henry's constant at 25 ° C. of 1.0 × 10 ⁻¹⁰ or more.

  In the present invention, the amine compound is particularly preferably any one of dicyclohexylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, and tetramethyl-1,6-hexanediamine.

  According to a second aspect of the present invention, there is provided a coolant obtained by diluting the water-soluble metalworking fluid composition according to the first aspect of the present invention, wherein the pH of the coolant is such that the amine compound is reduced to 1/2 equivalent of acid. It is characterized by not being lower than 1 or more neutralized pH.

  A third aspect of the present invention is a step of blending an amine compound having a linear, branched or cyclic saturated hydrocarbon group having 4 or more carbon atoms in a water-soluble metalworking fluid, 1/2 amine equivalent A step of adjusting the pH of the water-soluble metalworking fluid so that the pH of the water-soluble metalworking fluid does not fall below 1 or more than the pH neutralized with the acid of, using the amine compound as a gas-phase fungicide in the water-soluble metalworking fluid is there. In the third aspect of the present invention and the fourth aspect shown below, the “water-soluble metalworking fluid” refers to the water-soluble metalworking agent that is widely used in addition to the above-mentioned water-soluble metalworking fluid composition and coolant. It is a concept that includes metalworking fluids in general. In the present invention, the amine compound can function as a gas-phase fungicide in all such water-soluble metalworking fluids.

  A fourth aspect of the present invention is a gas-phase mold prevention method in a metal processing facility using a water-soluble metalworking fluid, which is a linear, branched or cyclic saturation having 4 or more carbon atoms in the water-soluble metalworking fluid. The step of blending the amine compound having a hydrocarbon group, the water-soluble metalworking fluid blended with the amine compound, so that the pH does not fall below 1 or more than the pH neutralized with 1/2 equivalent of acid. And a step of processing a metal using the water-soluble metalworking fluid whose pH has been adjusted.

  A fifth aspect of the present invention is a metal processing method for processing a metal while using the metal processing oil composition according to the first aspect of the present invention or the coolant according to the second aspect of the present invention. .

  According to the present invention, a predetermined amine is added to the water-soluble metalworking fluid composition, and the pH during use is set to a predetermined value or more. This makes it possible to inhibit the growth of mold in the gas phase when using water-soluble metalworking fluids, and avoid various plant troubles originating from mold growing in the gas phase from the gas-liquid interface in the liquid tank. Can do. That is, according to the present invention, it is possible to provide a water-soluble metalworking fluid composition that can suppress mold growth in the gas phase.

  By suppressing the growth of mold in the gas phase, it is possible to reduce the frequency of cleaning of places that are difficult to reach such as in the liquid tank and around the plant equipment. Moreover, the operating efficiency of the plant can be increased, and profitability can be improved.

It is a figure for demonstrating the antifungal evaluation test.

1. Water-soluble metalworking fluid composition 1.1. Amine compounds and pH
The water-soluble metalworking fluid composition according to the present invention contains an amine compound having a linear, branched or cyclic saturated hydrocarbon group having 4 or more carbon atoms, and the pH during use is 1 / It is characterized by not being lower than 1 or more than the pH neutralized with 2 equivalents of acid.

Thus, the water-soluble metalworking fluid composition according to the present invention has a first feature in that it contains a predetermined amine compound. As the amine compound, a compound having a vapor pressure at 25 ° C. of preferably 0.0075 mmHg or more, more preferably 0.01 mmHg or more, and particularly preferably 0.015 mmHg or more is used. Alternatively, a compound having a Henry's constant at 25 ° C. of preferably 1.0 × 10 ⁻¹⁰ or more, more preferably 1.0 × 10 ⁻⁹ or more, and particularly preferably 1.0 × 10 ⁻⁸ or more is used. With such an amine compound, growth of mold in the gas phase can be more effectively suppressed when a water-soluble metalworking fluid is used.

In the present invention, as the amine compound, dicyclohexylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, tetramethyl-1,6-hexanediamine, dibenzylamine, 1,3-bis (aminomethyl) cyclohexane, diethanolcyclohexylamine, 2 -Amino-2-methyl-1-propanol, monoisopropanolamine and the like are preferably used. In particular, dicyclohexylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, and tetramethyl-1,6-hexanediamine are preferable.
Table 1 below illustrates the vapor pressure or Henry constant at 25 ° C. for various amine compounds.

  In addition, the water-soluble metalworking fluid composition according to the present invention has a second feature that the pH at the time of use does not fall below 1 or more than the pH obtained by neutralizing the amine compound with 1/2 equivalent of acid. The “pH obtained by neutralizing an amine compound with 1/2 equivalent of acid” differs depending on the amine compound. Table 2 below summarizes the 1/2 neutralization pH of each amine compound.

  For example, when dimethylcyclohexylamine is used as the amine compound, the pH neutralized with 1/2 equivalent of acid is 9.8. Therefore, when the pH is not lower than 8.8 during use, When the oil composition is used, the growth of mold in the gas phase can be inhibited.

  In the present invention, by adding a predetermined amine compound, mold growth in the gas phase can be effectively inhibited without increasing the pH. Therefore, it is possible to suppress the occurrence of significant skin damage due to high pH and corrosion of non-ferrous metals. However, it is good also as the oil agent composition made into high pH according to a use.

  In addition, when the pH of the oil agent composition is not increased, it is also possible to develop an antibacterial / preservative effect in the liquid phase by using a heterocyclic compound.

  In adjusting the pH of the water-soluble metalworking fluid composition, various acids can be added. For example, an inorganic acid such as sulfuric acid or an organic acid such as acetic acid can be used without any particular limitation. It is particularly preferable to use an inorganic acid such as sulfuric acid.

  In the water-soluble metalworking fluid composition according to the present invention, the lower limit of the content of the amine compound is preferably 0.1% by mass or more, more preferably 1% by mass, based on the total composition (100% by mass). As described above, it is particularly preferably 2% by mass or more. The upper limit can be appropriately adjusted according to the application, but is, for example, 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 15% by mass or less. By setting the content of the amine compound in such a range, the growth of mold in the gas phase can be more appropriately inhibited.

1.2. Other Components The water-soluble metalworking fluid composition according to the present invention may contain various other components as long as the gas-phase fungicidal effect of the amine compound is not impaired. That is, it is possible to include a base oil, a surfactant, an extreme pressure additive, an antifoaming agent, a metal anticorrosive, and the like that are usually blended in a water-soluble metalworking fluid composition.

1.2.1. Specific examples of base oils include mineral oils, synthetic esters, and animal and vegetable oils. Isoparaffin, α-olefin (about 8 to 20 carbon atoms) or the like may be used. The water-soluble metalworking fluid composition of the present invention can further improve lubricity by containing the above base oil. In the water-soluble metalworking fluid composition of the present invention, the above base oils may be used alone or in combination of two or more.

Mineral oil refers to a component obtained by refining petroleum by distillation. As the mineral oil, a mineral oil that has undergone processes such as hydrogenation and reforming can be used. Specific examples of the mineral oil include spindle oil and machine oil. There are no particular limitations on the physical properties of the mineral oil. For example, the kinematic viscosity (40 ° C.) of the mineral oil is usually 0.1 mm ² / s or more, preferably 0.5 to 150 mm ² / s, more preferably 1 to 60 mm ² / s, and still more preferably 5 to 60 mm. ² / s. Moreover, the aniline point of the said mineral oil is 35-120 degreeC normally, Preferably it is 40-100 degreeC, More preferably, it is 45-100 degreeC, More preferably, it can be 50-90 degreeC. In addition, the said mineral oil may be used individually by 1 type, and may use 2 or more types together.

  Synthetic esters are usually carboxylic acids having 10 to 30 carbon atoms, preferably 12 to 28 carbon atoms, more preferably 15 to 25 carbon atoms, and alcohols having 1 to 30 carbon atoms, preferably 1 to 25 carbon atoms, more preferably 1 to 20 carbon atoms. Esters are used. The alcohol may be any of primary, secondary and tertiary alcohols. The alcohol may be any of monoalcohol, dialcohol, trialcohol, and tetraalcohol. Specific examples of the synthetic ester include methyl oleate, oleic acid-2-ethylhexyl, neopentyl glycol dioleate, trimethylolpropane trioleate, and pentaerythritol tetraoleate. Among these, oleic acid-2-ethylhexyl, neopentyl glycol dioleate, and trimethylolpropane trioleate are preferably used. In addition, the said synthetic ester may be used individually by 1 type, and may use 2 or more types together.

  Examples of animal and vegetable fats and oils include animal fats and oils such as pork fat, beef tallow, and fish oil, and vegetable fats and oils such as rapeseed oil, soybean oil, and palm oil. Moreover, as said animal and vegetable oil and fat, the hydrogenated product of the said animal and vegetable oil and fat can also be used. In addition, the said animal and vegetable fats and oils may be used individually by 1 type, and may use 2 or more types together.

  The content of the base oil is usually 80% by mass or less, preferably 0.1 to 80% by mass, more preferably 1 to 75% by mass when the total amount of the water-soluble metalworking fluid composition of the present invention is 100% by mass. %, More preferably 5 to 70% by mass, particularly preferably 10 to 60% by mass, and most preferably 20 to 60% by mass. When the content of the base oil is within the above range, the water-soluble metalworking fluid composition of the present invention is preferable because it exhibits excellent lubricity as well as excellent antiseptic properties.

1.2.2. Surfactant Examples of the surfactant include a cationic surfactant, an anionic surfactant, and a nonionic surfactant. In this invention, the said surfactant may be used individually by 1 type, and may use 2 or more types together. In the water-soluble metalworking fluid composition of the present invention, it is preferable to use one or more of an anionic surfactant and a nonionic surfactant.

  As said anionic surfactant, the salt or metal salt of a fatty acid and an amine compound, alkyl polyglycol ether carboxylic acid, acidic phosphate ester, petroleum sulfonate etc. are used, for example. As said fatty acid, the C6-C36 fatty acid currently used for the normal water-system metal processing agent is used. The fatty acid may be a monocarboxylic acid or a dicarboxylic acid. Examples of the fatty acid include caproic acid, caprylic acid, nonanoic acid, lauric acid, coconut oil fatty acid, oleic acid, erucic acid, ricinolenic acid, rapeseed oil fatty acid, ricinolenic acid condensate, C21 aliphatic dicarboxylic acid, adipic acid, sebacic acid , Dodecanoic acid, and dodecanedioic acid. Among these, coconut oil fatty acid, rapeseed fatty acid, oleic acid, ricinolenic acid, erucic acid, ricinolenic acid condensate, C21 aliphatic dicarboxylic acid, adipic acid, dodecanoic acid, and dodecanedioic acid are preferably used.

  As the amine compound for the surfactant, any amine compound including the above-described amine compound can be used, and any of an aliphatic amine, an alicyclic amine, and an aromatic amine may be used. Moreover, the amine compound which has another functional group may be sufficient. The amino group may be any of a primary amino group, a secondary amino group, and a tertiary amino group, and the number of amino groups is not particularly limited, and a monoamine compound, a diamine compound, a triamine compound, a tetraamine compound Either of these may be used. In the present invention, an amine compound having 2 to 36 carbon atoms, preferably 2 to 20 carbon atoms, more preferably 2 to 15 carbon atoms can be preferably used as the surfactant, and these may be used alone or in combination. More than one species can be used in combination.

  Examples of the aliphatic amine include octylamine, decylamine, laurylamine, oleylamine, and hexamethylenediamine. Examples of alicyclic amines include cyclohexylamine and dicyclohexylamine. Examples of aromatic amines include benzylamine and dibenzylamine.

  The anionic surfactant may be a surfactant in the water-soluble metalworking fluid composition by adding a fatty acid and an amine. In any case, in the present invention, a predetermined amine compound as a gas phase fungicide is essential, and in addition to this, an amine compound as a surfactant can be added.

  Examples of the metal salt include alkali metal salts such as sodium salt and potassium salt. Accordingly, specific examples of the fatty acid metal salt include alkali metal salts such as sodium salt and potassium salt of each fatty acid exemplified above.

  Specific examples of the nonionic surfactant include polyoxyalkylene alkyl ethers such as polyoxyethylene alkyl ether and polyoxyethylene polyoxypropylene alkyl ether, polyethylene glycol polypropylene glycol block polymers, coconut oil fatty acid diethanolamide, Examples include oleic acid diethanolamide or fatty acid monoester or diester of polyalkylene glycol.

  In the water-soluble metalworking fluid composition of the present invention, the content of the surfactant can be set in various ranges as required. When the total amount of the water-soluble metalworking fluid composition of the present invention is 100% by mass, the content of the surfactant is usually 1 to 40% by mass, preferably 3 to 35% by mass, more preferably 5 to 35% by mass. More preferably, it is 8-30 mass%, Most preferably, it is 10-30 mass%. When the content of the surfactant is within the above range, the water-soluble metalworking fluid composition of the present invention exhibits excellent liquid phase preservability. In the water-soluble metalworking fluid composition of the present invention, when an anionic surfactant and a nonionic surfactant are used in combination, the ratio of the two can be set in various ranges as required. When the total content of the anionic surfactant and the nonionic surfactant is 100% by mass, the content of the anionic surfactant is usually 30 to 95% by mass, preferably 40 to 95%. The mass% is more preferably 50 to 90 mass%, more preferably 60 to 90 mass%, and particularly preferably 70 to 90 mass%.

1.2.3. Extreme pressure additive, antifoaming agent, metal anticorrosive agent As the extreme pressure additive, antifoaming agent and metal anticorrosive agent, conventionally known ones can be used without any particular limitation. Specifically, sulfur-based extreme pressure additives such as sulfide mineral oil, sulfurized fatty oil, polysulfide and the like, and phosphorus-based extreme pressure additives such as phosphate esters as extreme pressure additives, and silicone-based materials such as dimethylsiloxane as antifoaming agents. Examples of antifoaming agents and metal anticorrosives include benzotriazole and thiadiazoles. What is necessary is just to adjust these content suitably according to the objective.

1.2.4. Liquid phase antibacterial and antiseptic component The present invention is characterized in that a fungicide effect in the gas phase is obtained, but in addition to the effect, from the viewpoint of ensuring antibacterial and antiseptic properties in the liquid phase, Ethers such as glycol ethers and glyceryl ethers can be blended. Furthermore, as described above, when the water-soluble metalworking fluid composition according to the present invention is used without increasing the pH, the heterocyclic compound can be effectively functioned. Liquid phase antibacterial and antiseptic properties can also be expressed.

1.2.5. Water The water-soluble metalworking fluid composition according to the present invention optionally contains water. The blending amount of water is not particularly limited, and is 0 to 80% by mass, and more preferably 0 to 60% by mass when the entire water-soluble metalworking fluid composition is 100% by mass. There are roughly three types of water-soluble metalworking fluids, so-called emulsions, solubles, and solutions. The amount of water contained in these is preferably 0-15% by weight for emulsions, 5-40% by weight for solubles, 20 to 60% by mass.

  As described above, the water-soluble metalworking oil composition according to the present invention contains a predetermined amine compound in addition to the base oil or the like usually blended in the oil, and has a pH during use. It is set to a predetermined value or more. This makes it possible to inhibit the growth of mold in the gas phase when using water-soluble metalworking fluids, and avoid various plant troubles originating from mold growing in the gas phase from the gas-liquid interface in the liquid tank. Can do.

2. Coolant The coolant according to the present invention is obtained by diluting the water-soluble metalworking fluid composition. Dilution may be performed using water. Or it can also be diluted by adding a separately prepared coolant to the water-soluble metalworking fluid composition. As for the dilution factor, the pH after dilution should be no more than 1 or more than the pH obtained by neutralizing the amine compound with 1/2 equivalent of acid, and is usually about 5 to 100 times.

3. Use of an amine compound as a gas phase fungicide The present invention also has an aspect relating to the use of an amine compound as a gas phase fungicide. That is, in a water-soluble metalworking fluid, a step of adding an amine compound having a linear, branched or cyclic saturated hydrocarbon group having 4 or more carbon atoms, and neutralizing the amine compound with 1/2 equivalent of acid The step of adjusting the pH of the water-soluble metalworking fluid so that the pH of the water-soluble metalworking fluid is not lower than 1 or more with respect to the measured pH. Thereby, a gas-phase antifungal property can be expressed in the water-soluble metalworking fluid. In this case, as the water-soluble metalworking fluid, in addition to the above-mentioned water-soluble metalworking fluid composition and coolant, known water-soluble metalworking fluids that are generally used may be used.

  Since specific examples of the amine compound that functions as a gas-phase fungicide, the compounding amount of the amine compound, and the like have already been described, they are omitted here.

4). Vapor-proof mold prevention method This invention also has the side surface which concerns on the vapor-phase mold prevention method in a metal processing facility. That is, a gas-phase mold prevention method in a metal processing facility using a water-soluble metalworking fluid, wherein the amine compound has a linear, branched or cyclic saturated hydrocarbon group having 4 or more carbon atoms in the water-soluble metalworking fluid. A step of adjusting the pH of the water-soluble metalworking fluid containing the amine compound so that the amine compound does not fall below 1 or more than the pH neutralized with 1/2 equivalent of acid, and and a step of processing a metal using a water-soluble metalworking fluid with adjusted pH. In this case, as the water-soluble metalworking fluid, in addition to the above-mentioned water-soluble metalworking fluid composition and coolant, known water-soluble metalworking fluids that are generally used may be used. The mold prevention method according to the present invention can effectively inhibit the growth of mold in the gas phase part, so that in the metal processing facility, mold grows in the gas phase part from the gas-liquid interface in the liquid tank. Various troubles of the originating plant can be avoided.

5. Metal processing method This invention also has the side concerning a metal processing method. That is, it is a metal processing method of processing a metal while using the metal processing oil composition or coolant according to the present invention. As described above, the metalworking fluid composition and coolant according to the present invention can effectively inhibit mold growth in the gas phase part under conditions where the pH is not too high. By processing the metal under such mild pH conditions, it is possible to effectively inhibit the growth of mold in the gas phase, while suppressing the occurrence of significant skin damage and corrosion of non-ferrous metals due to high pH. it can.

  Hereinafter, based on an Example, this invention is explained in full detail.

1. Gas-phase fungicidal properties of the amine compound alone The gas-phase fungicidal properties of the amine compound alone were evaluated using the following samples.
-Strain: As a strain (mold), a highly drug-resistant strain (genus Pseudallescheria) isolated from a water-soluble metalworking fluid use liquid in an implementation where mold damage was observed was used.
-Medium: Potato dextrose agar medium was used as the medium.
Sample: A 0.5% aqueous dispersion of an amine compound was used as a sample. The oil-soluble amine was stably dispersed in water by coexisting 1% nonionic activator. The pH of the specimen was adjusted with sulfuric acid.

  A medium (sterilized and dissolved in an autoclave) was poured into a deep (about 2 cm) sterilized petri dish (φ90 mm) and solidified. Here, a mold suspension (diluted 10-fold with sterilized saline) was drawn with a platinum loop.

  On the other hand, 5 ml of each sample related to the amine compound was dispensed into a sterile petri dish (φ60 mm).

  As shown in FIG. 1, each petri dish was installed, the outer periphery of the outer petri dish was sealed with a vinyl tape, and allowed to stand in a thermostatic bath at 30 ° C. for 3 days.

  The evaluation results are shown in Table 3 below. The criteria for determining antifungal properties in Table 3 were a six-step evaluation by visual observation, with 0 indicating no inhibition of mold growth and 5 indicating complete inhibition of mold growth.

  As is apparent from Table 3, dicyclohexylamine, dimethylcyclohexylamine, and dicyclohexylmethylamine exhibit strong gas-phase fungicide in a pH region of 10 or higher, and tetramethyl-1,6-hexanediamine exhibits a pH of 11 or higher. I understood it. Also, 3-methyl-4-octanol, 1,3-bis (aminomethyl) -cyclohexane and diethanolcyclohexylamine have a pH of 10 or more, and 2-amino-2-methyl-1-propanol and monoisopropanolamine have a pH of 11 or more and are weak. It showed gas-phase fungicidal properties. For other amines, only weak gas-phase fungicidal properties were confirmed in the high pH range, and the practicality was judged to be low. For reference, didecylmethylamine exhibited weak gas-phase fungicidal properties over a wide range of pH 6 or higher. Further, butyl benzoisothiazoline functioning as a liquid phase preservative could not confirm the gas phase fungicide.

2. Gas-phase fungicidal properties in the oil-blended system The gas-phase mold-proofing properties in the oil-blended system were evaluated using the following samples.
-Strain: As a strain (mold), a highly drug-resistant strain (genus Pseudallescheria) isolated from a water-soluble metalworking fluid use liquid in an implementation where mold damage was observed was used.
-Medium: A Czapek Docks agar medium was used as the medium.
Model oil agent: A nonionic activator, polyoxyalkylene (POA), alcohol, and mineral oil having a composition as shown in Table 4 below were blended to form an emulsion type model oil agent that does not exhibit gas-phase fungicide.
Amine compound: Dicyclohexylamine, dicyclohexylmethylamine, and dimethylcyclohexylamine, which showed remarkable gas-phase fungicidal properties in the above evaluation test, were used.
Sample: A predetermined amount of the above amine compound was added to a model oil, diluted to 5% with tap water, adjusted to a predetermined pH with sulfuric acid, an emulsion solution was prepared, and this was used as a sample.

  A medium (sterilized and dissolved in an autoclave) was poured into a deep (about 2 cm) sterilized petri dish (φ90 mm) and solidified. Here, a mold suspension (diluted 10-fold with sterilized saline) was drawn with a platinum loop.

  On the other hand, 5 ml of each sample related to the amine compound was dispensed into a sterile petri dish (φ60 mm).

  As shown in FIG. 1, each petri dish was installed, the outer periphery of the outer petri dish was sealed with a vinyl tape, and allowed to stand for 7 days in a 30 ° C. constant temperature bath.

  The evaluation results are shown in Table 5 below. The criteria for mold prevention in Table 5 were evaluated on a six-step scale by visual observation, with 0 indicating no inhibition of mold growth and 5 indicating complete inhibition of mold growth.

  As is apparent from Table 5, a compound that exhibits gas-phase fungicidal properties as an amine alone can exhibit gas-phase fungicidal properties without being interfered with by surfactants, mineral oils, etc., even in an oil compounding system. Indicated. As conditions for exhibiting a moderate or higher antifungal property, in the case of dicyclohexylamine, the final concentration is 0.25% by mass or more and pH 9.5 or more, and in the case of dicyclohexylmethylamine, the final concentration is 0.25% by mass or more and pH 9.0. As described above, in the case of dimethylcyclohexylamine, the final concentration was 0.40% by mass or more and pH 9.5 or more.

  Although the present invention has been described with reference to the most practical and preferred embodiments at the present time, the invention is not limited to the embodiments disclosed herein. However, it can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the water-soluble metalworking fluid composition, coolant, and amine compound gas-phase fungicide of such an amine compound with such a change. It should be understood that the use as an agent, the gas-phase mold prevention method, and the metal processing method are also included in the technical scope of the present invention.

  The water-soluble metalworking fluid composition and coolant according to the present invention can be suitably used as a lubricating oil and coolant during metalworking such as cutting, grinding, and plastic working.

Claims (2)

A coolant obtained by diluting a water-soluble metalworking fluid composition containing an amine compound ,
The amine compound is any one of dicyclohexylamine, dicyclohexylmethylamine, and dimethylcyclohexylamine,
The content of the amine compound in the coolant is 0.25% by mass or more,
The coolant has a pH of 9.0 or more,
Coolant. A metal processing method for processing a metal while using the coolant according to claim 1 .

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