JP2023016353A - Method for producing metal processing oil composition - Google Patents

Abstract

To provide a method for producing a metal processing oil composition that has a high processing ratio (rolling reduction ratio), suppresses an amount of abrasion powder generated, and has good oil removal property.SOLUTION: A method for producing a metal processing oil composition comprises: a mixing step of mixing a base oil (A) and an ester compound (B), wherein the mixing step comprises adjusting an amount (mass%) (m) of the ester compound (B) added so that m/a2 is 3.4 or more and less than 20 when a number of ester bonds of the ester compound (B) is defined as (a) and an added amount (mass%) of the ester compound (B) with respect to a total amount of the metal processing oil composition is defined as (m).SELECTED DRAWING: None

Description

The present invention relates to a method for producing a metalworking oil composition.

Metal working oil compositions are used for lubrication and cooling in most cases of metal working. By using a suitable metalworking oil composition, good workability can be obtained, and efficient production is possible. Moreover, the surface condition of the processed product becomes better.
For example, in the cold rolling of stainless steel and copper, by using an appropriate lubricating oil (rolling oil), it is possible to achieve a high reduction rate (reduction rate) that can be achieved in each rolling, and the target degree of processing It is possible to reduce the number of times of processing required.

Metalworking oil compositions generally contain additives in order to increase the working ratio (draft ratio).
For example, the metalworking oil composition of Patent Document 1 includes a base oil that is a mineral oil having a viscosity index of 70 to 115 and a sulfur content of 100 ppm to 2000 ppm by mass, and an ester, an alcohol and a phosphorus compound as additives. and at least one selected from It is disclosed that the metalworking oil composition has good lubricity under both high and low machining speed conditions, and is capable of sufficiently preventing surface damage to the workpiece.

JP 2014-70082 A

A high rolling reduction can be obtained by increasing the amount of the additive as described above in the metalworking oil composition.
However, depending on the material to be rolled and the rolling conditions, if the additive amount is set too high, excessive lubrication occurs, which induces slippage between the work rolls and the material, making normal rolling impossible. In addition, the amount of abrasion powder generated during processing increases due to slips and the like. The abrasion powder may not be completely removed even by washing in the post-process, which may impair product quality. Furthermore, among the additives, ester compounds in particular strongly adsorb to the surface of the material being rolled, making it difficult to remove, which may affect post-processes such as painting.

In the conventional metal working oil composition such as the metal working oil composition of Patent Document 1 described above, improvement of the working rate (reduction rate), suppression of the amount of abrasion powder generated, and removability of the composition itself ( There is a trade-off relationship between improvement in oil removal property, and no metalworking oil composition that satisfies all of these requirements has been produced.

The present invention has been made in view of the above circumstances, and provides a method for producing a metal working oil composition that has a high working ratio (rolling reduction), suppresses the amount of abrasion powder generated, and has good oil removal properties. The task is to provide

As a result of intensive studies by the inventors, in a method for producing a metal working oil composition containing a base oil and an ester compound, the amount of the ester compound to be added is optimal depending on the number of ester bonds of the ester compound. The inventors have found that the amounts are different, and have completed the present invention.
Specifically, the present invention employs the following configurations.

[1] A method for producing a metal working oil composition comprising a mixing step of mixing a base oil (A) and an ester compound (B), wherein in the mixing step, the ester bond of the ester compound (B) m/a ² is 3.4 or more and less than 20 A method for producing a metal working oil composition, comprising adjusting the addition amount (% by mass) (m) of the ester compound (B) so that
[2] The method for producing a metalworking oil composition according to [1], wherein the ester compound (B) contains butyl stearate.
[3] The method for producing a metal working oil composition according to [1] or [2], wherein the ester compound (B) contains butyl stearate and butyl palmitate.
[4] The method for producing a metalworking oil composition according to [1], wherein the ester compound (B) contains an ester composed of a dibasic acid and a monohydric alcohol having 8 to 10 carbon atoms.
[5] In the mixing step, adjusting the added amount (% by mass) (m) of the ester compound (B) so that the m/a ² is 5 or more and 10 or less, [1 ] to [4], the method for producing a metal working oil composition.

According to the present invention, it is possible to provide a method for producing a metalworking oil composition that has a high working rate (rolling reduction), suppresses the amount of wear debris generated, and has good oil removal properties.

In this specification, unless otherwise specified, the notation "X to Y" for numerical values X and Y is equivalent to "X or more and Y or less". In such notation, when only the numerical value Y is given a unit, the unit is applied to the numerical value X as well.

(Method for producing metal working oil composition)
The method for producing the metalworking oil composition of the present embodiment has a mixing step of mixing the base oil (A) and the ester compound (B).

[Mixing process]
In the method for producing the metal working oil composition of the present embodiment, in the mixing step, the number of ester bonds of the ester compound (B) is defined as (a), and the amount of the ester compound (B) added to the total amount of the metal working oil composition ( The addition amount (% by mass) (m) of the ester compound (B) is adjusted so that m/a ² is 3.4 or more and less than 20, where (m) is (% by mass). including.

In the mixing step in the method for producing the metal working oil composition of the present embodiment, m/a ² is 3.4 or more, preferably 4 or more, more preferably 4.5 or more, and still more preferably 5 or more.
Also, m/a ² is less than 20, preferably 18 or less, more preferably 16 or less, and still more preferably 15 or less.
In one embodiment, m/a ² is preferably 4-18, more preferably 4.5-16, even more preferably 5-15.

In the mixing step in the method for producing the metal working oil composition of the present embodiment, if m/a ² is 3.4 or more and less than 20, the working ratio (rolling reduction ratio), the suppression of the amount of abrasion powder generated, and , the oil agent removal property is well-balanced, and within the above preferable range, the working rate (rolling reduction), the ability to suppress the amount of abrasion powder generated, and the oil agent removal property are well-balanced.

The method for obtaining m/a ² when using two kinds of ester compounds (B) is as follows, and can be calculated by the same method when three or more kinds of ester compounds (B) are used.

For example, as the ester compound (B), the ester compound (B-1) having (a1) the number of ester bonds is (m1)% by mass, and the ester compound having (a2) the number of ester bonds ( When B-2) is used in combination with (m2)% by mass, m/a ² can be calculated by (m1/a1 ² )+(m2/a2 ² ).

In the mixing step, the method of mixing the base oil (A) and the ester compound (B) is not particularly limited, and a method of mixing by rotating a stirrer or stirring blade; A method of mixing using a bead mill or the like; a method of mixing by applying ultrasonic waves; a method of heating and melting in a vessel for mixing may be selected as appropriate from known methods.

<Base oil (A)>
As the base oil (A) in the method for producing the metalworking oil composition of the present embodiment, mineral oil and synthetic oil can be mentioned.

≪Mineral oil≫
As mineral oil, specifically, solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrogenation for lubricating oil fractions obtained by atmospheric distillation and vacuum distillation of crude oil Mineral oils obtained by applying one or more refining means such as refining, washing with sulfuric acid, and treatment with clay can be mentioned.

Examples of the mineral oil include Group I base oils (hereinafter sometimes referred to as "API Group I base oils") and Group II base oils (hereinafter sometimes referred to as "API Group II base oils"). ), or Group III base oils (hereinafter sometimes referred to as "API Group III base oils"), or mixtures thereof.
API Group I base oils are mineral base oils with a sulfur content of greater than 0.03 wt.% and/or a saturate content of less than 90 wt.
API Group II base oils are mineral base oils having a sulfur content of 0.03 mass % or less, a saturate content of 90 mass % or more, and a viscosity index of 80 or more and less than 120.
API Group III base oils are mineral base oils having a sulfur content of 0.03 wt.% or less, a saturates content of 90 wt.% or more, and a viscosity index of 120 or more.
As used herein, the viscosity index means a viscosity index measured according to JIS K 2283-2000. Further, in this specification, the "sulfur content in the lubricating base oil" shall be measured according to JIS K 2541-2003. In addition, the term "content of saturates in lubricating base oil" as used herein means a value measured according to ASTM D 2007-93.

The base oil may consist of one type of mineral oil, or may be a mixed base oil containing two or more types of mineral oil. In mixed base oils comprising two or more mineral oils, the API classifications of those mineral oils may be the same or different from each other. From the viewpoint of the stability of the metal working oil composition, the mineral oil preferably contains an API Group I base oil or an API Group II base oil.

The aromatic content in the mineral oil is not particularly limited, but is preferably 8% by volume or less, more preferably 6% by volume or less, and still more preferably 5% by volume or less from the viewpoint of working environment. Here, the aromatic content means a value measured according to the fluorescence indicator adsorption method of JIS K2536 "Petroleum products-hydrocarbon type test".

The naphthene content in the mineral oil is not particularly limited, but is preferably 10% by volume or more, more preferably 15% by volume or more, still more preferably 20% by volume or more, particularly preferably 25% by volume or more, and most preferably 30% by volume. % or more.
The naphthene content in the mineral oil is preferably 55% by volume or less, more preferably 50% by volume or less, still more preferably 45% by volume or less, particularly preferably 40% by volume or less, and most preferably 35% by volume or less. .
In one embodiment, the naphthenic content in the mineral oil is preferably 10-55% by volume, more preferably 15-50% by volume, even more preferably 20-45% by volume, particularly preferably 25-40% by volume, most preferably is 30-35% by volume.

The paraffin content in the mineral oil is not particularly limited, but is preferably 40% by volume or more, more preferably 45% by volume or more, still more preferably 50% by volume or more, particularly preferably 55% by volume or more, and most preferably 60% by volume. That's it.
The paraffin content in the mineral oil is preferably 85% by volume or less, more preferably 80% by volume or less, still more preferably 75% by volume or less, particularly preferably 70% by volume or less, and most preferably 65% by volume or less. .
In one embodiment, the paraffin content in the mineral oil is preferably 40-85% by volume, more preferably 45-80% by volume, even more preferably 50-75% by volume, particularly preferably 55-70% by volume, most preferably is 60-65% by volume.

In the present specification, naphthene content and paraffin content are determined by the molecular ion intensity obtained by mass spectrometry using FI ionization (using a glass reservoir). The measuring method is specifically shown below.

(1) An adsorption tube for elution chromatography with a diameter of 18 mm and a length of 980 mm is filled with 120 g of silica gel with a nominal diameter of 74 to 149 μm (grade 923 manufactured by Fuji Silysia Chemical Co., Ltd.) activated by drying at about 175° C. for 3 hours. .
(2) Inject 75 mL of n-pentane to pre-wet the silica gel.
(3) Accurately weigh about 2 g of a sample, dilute with an equal volume of n-pentane, and inject the obtained sample solution.
(4) When the liquid surface of the sample solution reaches the upper end of the silica gel, 140 mL of n-pentane is injected to separate the saturated hydrocarbon component, and the eluate is recovered from the lower end of the adsorption tube.
(5) The eluate is subjected to a rotary evaporator to remove the solvent to obtain a saturated hydrocarbon component.
(6) Type analysis of saturated hydrocarbon components with a mass spectrometer. As an ionization method in mass spectrometry, an FI ionization method using a glass reservoir is used, and a mass spectrometer, JMS-AX505H manufactured by JEOL Ltd. is used.

Measurement conditions are shown below.
Acceleration voltage: 3.0 kV, cathode voltage: -5 to -6 kV, resolution: about 500, emitter: carbon, emitter current: 5 mA, measurement range: mass number 35 to 700, auxiliary oven temperature: 300°C, separator temperature: 300 °C, main oven temperature: 350 °C, sample injection volume: 1 µL.

After isotope correction, molecular ions obtained by mass spectrometry were divided into paraffins (C _n H _2n+2 ) and naphthenes (C _n H _2n , C _n H _2n−2 , C _n H _2n−4 . . ) are classified and organized into two types, the fraction of each ionic strength is obtained, and the content of each type with respect to the entire saturated hydrocarbon component is determined. Next, based on the content of saturated hydrocarbon components, the content of paraffins and naphthenes in the entire sample is determined.

The details of data processing by the type analysis method of FI method mass spectrometry are described in "Nisseki Review" Vol. .

≪Synthetic oil≫
Synthetic oils include polyolefins, alkylbenzenes, and the like.

• Polyolefins Polyolefins include homopolymers or copolymers of olefin monomers having 2 to 16 carbon atoms, preferably 2 to 12 carbon atoms, hydrides of these polymers, and the like. The olefin monomers may be α-olefins, internal olefins, linear olefins, or branched olefins. Specific examples of such olefin monomers include ethylene, propylene, 1-butene, 2-butene, isobutene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, and hexadecene. and mixtures thereof.

• Alkylbenzene Alkylbenzenes preferably have 1 to 4 alkyl groups of 1 to 40 carbon atoms in the molecule. In addition, the alkyl group of alkylbenzene may be linear or branched, but a branched alkyl group is preferable from the viewpoint of stability, viscosity characteristics, etc., and is particularly easy to obtain. Therefore, branched alkyl groups derived from oligomers of olefins such as propylene, butene and isobutylene are more preferred.

As the base oil (A) in the method for producing a metalworking oil composition of the present embodiment, one of the mineral oils and/or synthetic oils described above may be used alone, or two or more may be used in combination. However, it is preferable to use one of the mineral oils mentioned above, or to use two or more of them in combination.

The amount of the base oil (A) added in the method for producing the metal working oil composition of the present embodiment is not particularly limited, and may be, for example, 40 to 95% by mass with respect to the total amount of the metal working oil composition. , 50 to 95% by mass.

The kinematic viscosity at 40° C. of the base oil (A) in the method for producing the metal working oil composition of the present embodiment is preferably 2.0 mm ² /s or more, more preferably 3, from the viewpoint of workability in cold rolling. 0 mm ² /s or more, more preferably 4.0 mm ² /s or more.
Also, from the viewpoint of oil agent removal properties, it is preferably 25 mm ² /s or less, more preferably 20 mm ² /s or less, and even more preferably 15 mm ² /s or less.
In one embodiment, the kinematic viscosity of the base oil (A) at 40° C. is preferably 3.0 to 20 mm ² /s, more preferably 4.0 to 15 mm ² /s. In the present specification, "kinematic viscosity at 40°C" means kinematic viscosity at 40°C defined in JIS K 2283-2000.

<Ester compound (B)>
The ester compound (B) in the method for producing the metalworking oil composition of the present embodiment is not particularly limited as long as it is a compound having an ester bond.

As the ester compound (B), specifically, the following esters (i) to (vii) can be used.
(i) Ester of monohydric alcohol and monobasic acid (ii) Ester of polyhydric alcohol and monobasic acid (iii) Ester of monohydric alcohol and polybasic acid (iv) Polyhydric alcohol and polybasic acid (v) Esters of mixed alcohols of monohydric and polyhydric alcohols with polybasic acids (vi) Esters of polyhydric alcohols with mixed carboxylic acids of monobasic and polybasic acids (vii) Monohydric alcohols and Esters of mixed alcohols of polyhydric alcohols and mixed carboxylic acids of monobasic and polybasic acids

Monohydric alcohols include, for example, monohydric alcohols having 1 to 24 carbon atoms.
The monohydric alcohol may be linear or branched.
Specifically, methanol, ethanol, linear or branched propanol, linear or branched butanol, linear or branched octanol, linear or branched nonanol, linear Linear or branched decanol, linear or branched undecanol, linear or branched dodecanol, linear or branched tridecanol, linear or branched tetradecanol , linear or branched pentadecanol, linear or branched hexadecanol, linear or branched heptadecanol, linear or branched octadecanol, linear linear or branched nonadecanol, linear or branched eicosanol, linear or branched heneicosanol, linear or branched tricosanol, linear or branched Tetracosanols and mixtures thereof.

Examples of polyhydric alcohols include dihydric to decahydric alcohols, preferably dihydric to hexahydric alcohols. The polyhydric alcohol may be linear or branched.
Specifically, ethylene glycol, diethylene glycol, polyethylene glycol (3-15 mer of ethylene glycol), propylene glycol, dipropylene glycol, polypropylene glycol (3-15 mer of propylene glycol), 1,3-propanediol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,2-propanediol, 2-methyl-1,3-propanediol, 1,2-pentanediol, dihydric alcohols such as 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol and neopentyl glycol; tetraglycerin), trimethylolalkanes (trimethylolethane, trimethylolpropane, trimethylolbutane, etc.) and 2-8mers thereof, pentaerythritol and 2-4mers thereof, 1,2,4-butanetriol, Polyvalents such as 1,3,5-pentanetriol, 1,2,6-hexanetriol, 1,2,3,4-butanetetrol, sorbitol, sorbitan, sorbitol glycerin condensate, adonitol, arabitol, xylitol and mannitol alcohol; sugars such as xylose, arabinose, ribose, rhamnose, glucose, fructose, galactose, mannose, sorbose, cellobiose, maltose, isomaltose, trehalose, sucrose; mixtures thereof;

Examples of monobasic acids include fatty acids having 6 to 24 carbon atoms.
The fatty acid may be linear or branched. Moreover, the fatty acid may be a saturated fatty acid or an unsaturated fatty acid.
Specifically, linear or branched hexanoic acid, linear or branched octanoic acid, linear or branched nonanoic acid, linear or branched decanoic acid, linear linear or branched undecanoic acid, linear or branched dodecanoic acid, linear or branched tridecanoic acid, linear or branched tetradecanoic acid, linear or branched Pentadecanoic acid, linear or branched hexadecanoic acid (palmitic acid), linear or branched octadecanoic acid (stearic acid), linear or branched hydroxyoctadecanoic acid, linear or Branched nonadecanic acid, linear or branched eicosanoic acid, linear or branched heneicosanoic acid, linear or branched docosanoic acid, linear or branched tricosanoic acid , linear or branched saturated fatty acids such as tetracosanoic acid; linear or branched hexenoic acid, linear or branched heptenoic acid, linear or branched octenoic acid, linear linear or branched nonenoic acid, linear or branched decenoic acid, linear or branched undecenoic acid, linear or branched dodecenoic acid, linear or branched of tridecenoic acid, linear or branched tetradecenoic acid, linear or branched pentadecenic acid, linear or branched hexadecenoic acid, linear or branched octadecenoic acid, linear linear or branched hydroxyoctadecenoic acid, linear or branched nonadecenic acid, linear or branched eicosenoic acid, linear or branched heneicosenoic acid, linear or branched linear or branched docosenoic acid, linear or branched tricosenoic acid, linear or branched unsaturated fatty acid such as tetracosenoic acid; and mixtures thereof.

Examples of polybasic acids include dibasic acids (dicarboxylic acids) having 6 to 16 carbon atoms, tribasic acids (tricarboxylic acids) having 6 to 16 carbon atoms, and the like.
The dibasic acid and tribasic acid may be linear or branched. Moreover, the dibasic acid and tribasic acid may be saturated fatty acids or unsaturated fatty acids.

Specific examples of the dibasic acid include ethanedioic acid, propanedioic acid, linear or branched butanedioic acid, linear or branched pentanedioic acid, linear or branched hexanedioic acid, acid (adipic acid), linear or branched octanedioic acid, linear or branched nonanedioic acid, linear or branched decanedioic acid, linear or branched undecanedioic acid, linear or branched dodecanedioic acid, linear or branched tridecanedioic acid, linear or branched tetradecanedioic acid, linear or branched heptadecanedioic acid, linear or branched hexadecanedioic acid, linear or branched hexenedioic acid, linear or branched octenedioic acid, linear or branched nonenedioic acid, linear or branched decenedioic acid, linear linear or branched undecenedioic acid, linear or branched dodecenedioic acid, linear or branched tridecenedioic acid, linear or branched tetradecenedioic acid, linear or branched Heptadecenedioic acid, linear or branched hexadecenedioic acid, mixtures thereof, and the like.

Specific examples of the tribasic acid include trimellitic acid.

As the ester compound (B) in the method for producing a metalworking oil composition of the present embodiment, (i) an ester of a monohydric alcohol and a monobasic acid, or (iii) an ester of a monohydric alcohol and a polybasic acid is preferably

(i) As an ester of a monohydric alcohol and a monobasic acid, specifically, the number of carbon atoms from the viewpoint of the balance between the processing rate (rolling reduction), the suppression of the amount of wear debris generated, and the ability to remove oil It is preferably an ester composed of a monohydric alcohol having 1 to 24 carbon atoms and a fatty acid having 6 to 24 carbon atoms, and is composed of a monohydric alcohol having 4 to 10 carbon atoms and a fatty acid having 10 to 18 carbon atoms. Esters are more preferred.
More specifically, butyl stearate and butyl palmitate are preferred.

(iii) As an ester of a monohydric alcohol and a polybasic acid, specifically, the number of carbon atoms from the viewpoint of the balance between the processing rate (rolling reduction rate), the ability to suppress the amount of wear debris generated, and the ability to remove oil An ester consisting of a monohydric alcohol having 1 to 24 carbon atoms and a dibasic acid having 6 to 16 carbon atoms is preferred, and an ester consisting of an alcohol having 8 to 10 carbon atoms and a dibasic acid having 6 to 16 carbon atoms. is preferred.
More specifically, diisononyl adipate and di(2-ethylhexyl) adipate are preferred.

The ester compound (B) in the method for producing a metalworking oil composition of the present embodiment may be used singly or in combination of two or more.
When the ester compound (B) is a mixture of two or more ester compounds, butyl stearate and A mixture of butyl palmitates is preferred.

As the ester compound (B) in the method for producing the metal working oil composition of the present embodiment, among the above, the group consisting of butyl stearate, butyl palmitate, diisononyl adipate, and di(2-ethylhexyl) adipate It is preferably one or more ester compounds selected from

The amount of the ester compound (B) added in the method for producing the metalworking oil composition of the present embodiment is appropriately adjusted so that m/ ^a2 is 3.4 or more and less than 20, as described above.
The amount of the ester compound (B) added is, for example, 5 to 50% by mass with respect to the total amount of the metalworking oil composition.

<Optional component>
In the mixing step in the method for producing the metalworking oil composition of the present embodiment, components (optional components) other than the base oil (A) and the ester compound (B) described above are added to the extent that the effects of the present invention are not impaired. You may mix further.
The optional components include antioxidants such as phenol-based and amine-based antioxidants; anti-mist agents such as polyisobutene and poly-α-olefin; metal deactivators such as benzotriazole and derivatives thereof; alcohols, fatty acids, ethers and amines. Oily agents such as; alkyl or alkenyl succinic acid derivatives, polyhydric alcohol partial esters, metal sulfonates, amines and other rust inhibitors; phosphorus compounds such as tricresyl phosphate, organic metal compounds such as zinc dialkyldithiophosphate, etc. antifoaming agents such as silicone antifoaming agents;

In the method for producing the metalworking oil composition of the present embodiment, the amount of the ester compound (B) added is controlled so that m/ ^a2 is 3.4 or more and less than 20 in the mixing step.
For example, when the ester compound (B) is a monoester, it has high lubricity, so that even a small addition amount can improve the working ratio (rolling reduction ratio). On the other hand, if the addition amount is too large, excessive lubrication occurs, normal machining cannot be performed, and a large amount of abrasion powder is generated. On the other hand, if the amount added is too large, the monoester has a high adsorptivity to the surface of the material to be processed, so that the removal of the oil agent is lowered.
In addition, when the ester compound (B) is a diester, triester, or the like, the adsorbability to the surface of the workpiece is inferior to that of the above monoester. It is necessary to increase the amount of (B) added to some extent.
Therefore, as described above, it is important to set the amount of the ester compound (B) to be added appropriately according to the number of ester bonds.
According to the method for producing a metal working oil composition of the present embodiment, it is possible to produce a metal working oil composition that has a high working rate (rolling reduction), suppresses the amount of wear debris generated, and has good oil removal properties. be able to.

(Metal working oil composition)
The metal working oil composition of the present embodiment is a metal working oil composition obtained by the method for producing a metal working oil composition described above.
In the method for producing the metal working oil composition described above, since the amount of the ester compound (B) added is controlled so that m/a ² is 3.4 or more and less than 20, the metal working of the present embodiment The oil composition can increase the working rate (reduction rate), can suppress the amount of abrasion powder generated, and has good oil removal properties.

The metalworking oil composition of the present embodiment is preferably used for metalworking a work material containing at least one selected from stainless steel, copper, titanium, nickel, aluminum, and alloys containing these as main components.

The metal working oil composition of the present embodiment is particularly suitable for use when metal working is plastic working or cold rolling.

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

<Preparation of base oil (A)>
A base oil (mineral oil) having physical properties shown in Table 1 below was prepared.

<Preparation of ester compound (B)>
An ester compound (B) shown below was prepared.
(B)-1: butyl stearate (number of ester bonds (a) = 1)
(B)-2: butyl palmitate (number of ester bonds (a) = 1)
(B)-3: diisononyl adipate (number of ester bonds (a) = 2)
(B)-4: tris(2-ethylhexyl) trimellitate (number of ester bonds (a) = 3)
(B)-5: Di(2-ethylhexyl) adipate (number of ester bonds (a) = 2)

<Production of metal working oil composition>
[Mixing process]
Each component shown in Tables 2 to 7 was mixed to produce a metalworking oil composition of each example.

[Evaluation of maximum rolling reduction]
≪Test material≫
SUS304 (0.7mm thickness, 43mm width, 350m length (coil))

≪Measurement conditions≫
Work roll diameter: 50mm
Rolling speed: 44m/min
Supply amount of metal working oil composition: 15 L/min
Temperature of metalworking oil composition: 30°C

Using the metal working oil composition of each example, the test material was rolled. Specifically, rolling was started from a rolling reduction of 25%, rolling was performed for 30 seconds after the load was stabilized, and then the rolling reduction was increased by 1%. Thereafter, this process was repeated to determine the maximum rolling reduction (%) at which normal rolling was possible without seizure.
For confirmation of burn-in, those that could not be determined visually were observed using an optical microscope (400x magnification). The results obtained are shown in Tables 2-7.

[Evaluation of wetted area and wear debris stain]
≪Test material≫
SUS304 (0.7mm thickness, 43mm width, 350m length (coil))

After the test material was rolled at a rolling reduction of 25%, it was allowed to stand in a constant temperature bath at 180°C for 10 hours. After that, 10 test pieces of 43 mm×43 mm were cut from the rolled test material at a portion of about 280 m from the rolling start site. Next, each test piece was cleaned in a 1 L beaker containing 500 mL of n-hexane with an ultrasonic cleaner for 60 seconds. The test piece was then taken out and dried thoroughly.
Next, the test piece was immersed in ion-exchanged water, taken out, and allowed to stand still for 10 seconds to determine the water wetted area ratio (%) of the test piece. If the oil is completely removed, the wetted area is 100%. The average value of 10 test pieces was evaluated according to the following criteria. The results obtained are shown in Tables 2-7.
≪Evaluation Criteria≫
A: 80% or more B: 70% or more and less than 80% C: 60% or more and less than 70% The water wet area is calculated according to JIS K2246 Rust prevention oil rust generation rate measurement method, and the surface of the test piece is 100%. The area ratio (%) was calculated by dividing and visually counting the water-wet squares.

In addition, abrasion powder (generated during rolling) on the surface of the test piece washed with n-hexane and sufficiently dried was observed.
Specifically, in accordance with JIS K2246, the surface of the test piece is divided into 100, the squares in which stains are observed are visually counted, and the average value of the 10 test pieces is evaluated according to the following criteria. bottom. The results obtained are shown in Tables 2-7.
≪Evaluation Criteria≫
S: 0
A: 1 or more and less than 5 B: 5 or more and less than 10 C: 10 or more and less than 15 D: 15 or more and less than 20 E: 20 or more

In Tables 2 to 7, the numerical values of the base oil (A) and the ester compound (B) are the amount (% by mass) added to the total amount of 100% by mass of the metal working oil composition.

As shown in Tables 2 to 7, the metal working oil compositions produced by the methods for producing metal working oil compositions of Examples are the metal working oil compositions produced by the methods for producing metal working oil compositions of Comparative Examples. It was confirmed that the maximum rolling reduction, water wetted area, and wear staining were excellent in a well-balanced manner.
Therefore, the metal working oil composition produced by the method for producing a metal working oil composition of the example has a high working rate (rolling reduction), suppresses the amount of abrasion powder generated, and has good oil removal properties. I was able to confirm something.

As shown in Table 2, in the methods for producing metalworking oil compositions of Comparative Examples 1 and 2, diesters and triesters having a relatively large number of ester bonds were used as the ester compound (B). Since the amount of the diester and triester added is small, m/a ² is lower than 3.4. Therefore, the value of the maximum rolling reduction was low, and the workability was inferior.

As shown in Table 3, in the method for producing a metal working oil composition of Comparative Example 3, a triester having a relatively large number of ester bonds is used as the ester compound (B). Since the amount added is small, m/ ^a2 is lower than 3.4. Therefore, the value of the water wetted area was low, and the oil agent removability was poor.

As shown in Table 4, in the method for producing the metalworking oil composition of Comparative Example 4, a monoester having a small number of ester bonds was used as the ester compound (B). m/ ^a2 is 20 or more. Therefore, there was a lot of abrasion powder stains.
In the method for producing a metalworking oil composition of Comparative Example 5, a triester having a relatively large number of ester bonds is used as the ester compound (B). / ^a2 is lower than 3.4. Therefore, there was a lot of abrasion powder stains.

As shown in Table 5, in the method for producing the metal working oil composition of Comparative Example 6, a monoester having a small number of ester bonds was used as the ester compound (B). m/ ^a2 is 20 or more. Therefore, there was a lot of abrasion powder stains.

As shown in Table 6, in the method for producing the metal working oil composition of Comparative Example 7, a monoester having a small number of ester bonds was used as the ester compound (B). m/ ^a2 is 20 or more. Therefore, there was a lot of abrasion powder stains.
In the method for producing the metalworking oil composition of Comparative Example 8, a triester having a relatively large number of ester bonds is used as the ester compound (B). / ^a2 is lower than 3.4. Therefore, the value of the water wetted area was low, and the oil agent removability was poor. In addition, there was a lot of wear powder stains.

As shown in Table 7, in the method for producing the metal working oil composition of Comparative Example 9, a monoester having a small number of ester bonds was used as the ester compound (B). m/ ^a2 is 20 or more. Therefore, the value of the water wetted area was low, and the oil agent removability was poor. In addition, there was a lot of wear powder stains.

Claims (5)

A method for producing a metal working oil composition comprising a mixing step of mixing a base oil (A) and an ester compound (B),
In the mixing step, when the number of ester bonds of the ester compound (B) is defined as (a) and the added amount (% by mass) of the ester compound (B) with respect to the total amount of the metal working oil composition is defined as (m) and adjusting the addition amount (% by mass) (m) of the ester compound (B) so that m/a ² is 3.4 or more and less than 20. . 2. The method for producing a metalworking oil composition according to claim 1, wherein said ester compound (B) contains butyl stearate. 3. The method for producing a metalworking oil composition according to claim 1, wherein said ester compound (B) contains butyl stearate and butyl palmitate. 2. The method for producing a metalworking oil composition according to claim 1, wherein said ester compound (B) comprises an ester composed of a dibasic acid and a monohydric alcohol having 8 to 10 carbon atoms. Claims 1 to 4, wherein in the mixing step, the addition amount (% by mass) (m) of the ester compound (B) is adjusted so that the m/a ² is 5 or more and 10 or less. A method for producing a metal working oil composition according to any one of the above.