JP2023142188A - Metalworking oil - Google Patents

Abstract

To provide a metalworking oil that has excellent lubricity and generates little oil smoke during metalworking.SOLUTION: There are provided a metalworking oil that contains 60 mass% or more and 95 mass% or less of a gas-liquefied oil (GTL) with a flash point of 190°C or higher, and 5 mass% or more and 40 mass% or less of a sulfurized oil or fat as a sulfur-based additive; and a metalworking oil that contains 60 mass% or more and 90 mass% or less of a gas-liquefied oil (GTL) with a flash point of 190°C or higher, and 10 mass% or more and 30 mass% or less of a sulfurized ester as a sulfur-based additive.SELECTED DRAWING: None

Description

The present invention relates to a metalworking fluid used in metalworking such as heading, press working, and cutting.

Conventionally, as disclosed in Patent Document 1, metalworking fluids have been used as lubricants in metalworking to prevent seizure due to friction between tools and workpieces, deterioration of the quality of workpieces, and progression of tool wear. is used.

Patent No. 6569150

Conventional metalworking fluids have a problem in that oil smoke is generated from metalworking fluids due to the heat generated during metalworking, which worsens the working environment.

An object of the present invention is to provide a metalworking fluid that has excellent lubricity and generates less oil smoke during metalworking.

The metal working fluid of the present invention is characterized in that it contains 60% by mass or more and 95% by mass or less of GTL with a flash point of 190° C. or higher, and 5% by mass or more and 40% by mass or less of sulfurized fat as a sulfur additive. .

According to this configuration, by including GTL having a flash point of 190° C. or higher, the amount of oil smoke generated during metal processing can be reduced. In addition, by including sulfurized oil as a sulfur-based additive, it is possible to impart lubricity to metalworking fluids, and the amount of oil smoke generated during metalworking increases compared to when sulfur-based additives are not included. This can be suppressed. Therefore, it is possible to provide a metalworking fluid that has excellent lubricity and generates less oil smoke during metalworking.

Another metalworking fluid of the present invention is characterized in that it contains 60% by mass or more and 90% by mass or less of GTL with a flash point of 190° C. or higher, and contains 10% by mass or more and 30% by mass or less of sulfurized ester as a sulfur additive. shall be.

According to this configuration, by including GTL having a flash point of 190° C. or higher, the amount of oil smoke generated during metal processing can be reduced. In addition, by including sulfurized ester as a sulfur-based additive, it is possible to impart lubricity to metalworking fluids, and the amount of oil smoke generated during metalworking increases compared to when sulfur-based additives are not included. This can be suppressed. Therefore, it is possible to provide a metalworking fluid that has excellent lubricity and generates less oil smoke during metalworking.

In this case, it is preferable that the metal sulfonate is contained in an amount of 2% by mass or more and 15% by mass or less.

According to this configuration, the amount of oil smoke generated during metal processing can be further reduced.

In this case, it is preferable that zinc dithiophosphate is contained in an amount of 2% by mass or more and 15% by mass or less.

According to this configuration, the lubricity of the metal working fluid can be improved.

The metal working fluid of the present invention contains GTL and a sulfur-based additive. Further, the metal working fluid may contain at least one of a metal sulfonate and zinc dithiophosphate in addition to GTL and a sulfur additive.

(GTL)
The metalworking fluid contains GTL, ie, Gas To Liquid, as a base oil. GTL is, for example, synthesized from natural gas by Fischer-Tropsch reaction.

Among GTL, metalworking fluids include those with a flash point of 190° C. or higher. The higher the flash point of GTL, the more the amount of oil smoke generated during metal processing can be reduced. The flash point of GTL is preferably 200°C or higher, more preferably 230°C or higher. The metal working fluid may contain one type of GTL, or may contain two or more types of GTL.

As described below, the content of GTL in the metalworking fluid is 60% by mass or more and 95% by mass or less when sulfurized oil or fat is included as a sulfur-based additive. When the GTL content is 60% by mass or more, the amount of oil smoke generated during metal processing can be reduced. When the content of GTL is 95% by mass or less, the necessary amount of sulfurized oil and fat can be added. Further, as will be described later, the content of GTL in the metal working fluid is 60% by mass or more and 90% by mass or less when a sulfurized ester is included as a sulfur-based additive. When the GTL content is 60% by mass or more, the amount of oil smoke generated during metal processing can be reduced. When the GTL content is 90% by mass or less, the necessary amount of sulfurized ester can be added.

The kinematic viscosity of GTL at 40° C. is preferably 50 mm ² /s or less. When the kinematic viscosity of GTL is 50 mm ² /s or less, workability in metal processing can be ensured. Note that the higher the kinematic viscosity of GTL, the higher the flash point of GTL tends to be.

(Sulfur additive)
The metal working fluid contains at least one of a sulfurized oil and a sulfurized ester as a sulfur additive. That is, of the sulfurized oil and fat and sulfurized ester, the metal processing fluid may contain only the sulfurized oil, only the sulfurized ester, or both the sulfurized oil and the sulfurized ester. By containing at least one of sulfurized oil and sulfurized ester among sulfur-based additives, the metalworking fluid suppresses an increase in the amount of oil smoke generated during metalworking compared to when it does not contain sulfur-based additives. At the same time, it is possible to impart lubricity to the metalworking fluid.

Sulfurized fats and oils are sulfides of fats and oils. Examples of the fats and oils include beef tallow, lard, soybean oil, rapeseed oil, coconut oil, and palm oil. The metal working fluid may contain one type of sulfurized oil or fat, or may contain two or more types of sulfurized oil or fat.

The content of sulfurized oil and fat in the metalworking fluid is 5% by mass or more and 40% by mass or less. When the content of the sulfurized oil is 5% by mass or more, appropriate lubricity can be imparted to the metalworking fluid. By setting the content of sulfurized fats and oils to 40% by mass or less, it is possible to avoid an increase in the amount of oil smoke generated during metal processing.

Examples of the sulfurized ester include sulfurized methyl oleate and sulfurized methyl linoleate. The metal working fluid may contain one type of sulfurized ester, or may contain two or more types of sulfurized ester.

The content of sulfurized ester in the metal working fluid is 10% by mass or more and 30% by mass or less. When the content of the sulfurized ester is 10% by mass or more, appropriate lubricity can be imparted to the metalworking fluid. By setting the content of sulfurized ester to 30% by mass or less, it is possible to avoid an increase in the amount of oil smoke generated during metal processing. The content of sulfurized ester is preferably 10% by mass or more and 20% by mass or less.

(metal sulfonate)
The metalworking fluid may contain a metal sulfonate. When the metal working fluid contains a metal sulfonate, the amount of oil smoke generated during metal working can be further reduced. Examples of metal sulfonates include alkali metal sulfonates and alkaline earth metal sulfonates. As the alkali metal sulfonate, sodium sulfonate can be mentioned. Examples of alkaline earth metal sulfonates include magnesium sulfonate, calcium sulfonate, and barium sulfonate. The metal working fluid may contain one type of metal sulfonate, or may contain two or more types of metal sulfonate.

The content of metal sulfonate in the metal working fluid is, for example, 2% by mass or more and 15% by mass or less. When the metal sulfonate content is 2% by mass or more, the amount of oil smoke generated during metal processing can be effectively reduced. By setting the content of metal sulfonate to 15% by mass or less, necessary amounts of GTL and sulfur-based additives can be added.

(zinc dithiophosphate)
The metalworking fluid may include zinc dithiophosphate. When the metalworking fluid contains zinc dithiophosphate, the lubricity of the metalworking fluid can be improved. Examples of zinc dithiophosphate include zinc dialkyldithiophosphate and zinc diaryldithiophosphate. The metalworking fluid may contain one type of zinc dithiophosphate, or may contain two or more types of zinc dithiophosphate. The content of zinc dithiophosphate in the metalworking fluid is, for example, 2% by mass or more and 15% by mass or less.

(other ingredients)
In addition to the above-mentioned metal sulfonates and zinc dithiophosphate, metalworking fluids contain one or more of higher alcohols, antioxidants, rust preventives, and pour point depressants as components other than GTL and sulfur-based additives. May contain. Further, the metal processing fluid may contain one or more of mineral oil, synthetic hydrocarbon, nonferrous metal corrosion inhibitor, and ester compound.

When the metal working fluid contains a higher alcohol, it is possible to improve the compatibility between GTL, which is a nonpolar solvent, and a sulfur-based additive, which is a polar additive. Examples of higher alcohols include those having 6 or more carbon atoms. The metal working fluid may contain one type of higher alcohol, or may contain two or more types of higher alcohol.

Examples of the antioxidant include phenolic antioxidants and amine antioxidants. The metal working fluid may contain one type of antioxidant, or may contain two or more types of antioxidant.

Examples of the rust preventive include alkylbenzene sulfonates, alkenyl succinates, benzotriazole, tolyltriazole, and thiazole compounds. The metal working fluid may contain one type of rust preventive agent, or may contain two or more types of rust preventive agents.

Examples of the pour point depressant include alkylbenzene sulfonates and alkenyl succinates in which polyalkyl methacrylates, polyalkyl acrylates, polyisobutylene, polybutene, alkylnaphthalene condensation products, alkylphenol condensation products, etc. can be used. can. The metalworking fluid may contain one type of pour point depressant, or may contain two or more types of pour point depressants.

(Metal processing method)
The type of metal working in which the metal working fluid is used is not particularly limited, but it can be used, for example, in forging, press working, or cutting.

(Preparation of metal working fluid)
Metalworking fluids of Examples 1 to 10 and Comparative Examples 1 to 15 were prepared by putting each material for metalworking fluids in the amounts shown in Tables 1 to 3 into a container and stirring. In Tables 1 to 3, the amount of each component is shown in mass %.

Each component shown in Tables 1 to 3 is as follows.
GTL-2...Kinematic viscosity (40°C): 18mm ² /s, flash point: 230°C
GTL-3...Kinematic viscosity (40°C): 43mm ² /s, flash point: 265°C
Mineral oil-2...Group I (paraffinic), kinematic viscosity (40°C): 20mm ² /s, flash point: 222°C
Mineral oil-3...Group I (paraffinic), kinematic viscosity (40°C): 45mm ² /s, flash point: 242°C
Sulfurized oil (derived from vegetable oil)...Sulfur content: 10% by mass
Sulfurized ester...Sulfur content: 10% by mass
Polysulfide...Sulfur content: 39% by mass
Calcium sulfonate (mineral oil-containing)...base number: 400 mgKOH/g, content of calcium sulfonate: 50% by mass
Zinc dithiophosphate (mineral oil-containing): Sulfur content 17.1% by mass, content of zinc dithiophosphate: 75% by mass

The flash point was measured by the COC method in accordance with JIS K2265. Kinematic viscosity was measured in accordance with JIS K2283.

(Amount of oil smoke generated)
For the metalworking fluids of Examples 1 to 10 and Comparative Examples 1 to 15, the weight loss rate was measured as an evaluation index of the amount of oil smoke generated. It can be said that the lower the weight reduction rate, the smaller the amount of oil smoke generated. The weight loss rate was determined by increasing the temperature from 35°C to 550°C at a rate of 20°C/min in a nitrogen atmosphere of 300 mL/min using a differential thermogravimetric simultaneous measuring device (product name: TG/DTA6300, manufactured by Seiko Instruments Inc.). The weight change rate was measured and evaluated as follows.
・When using GTL-2 or mineral oil-2 Evaluation A: Weight loss rate at 220°C is less than 10%, weight loss rate at 250°C is less than 20%, and weight loss rate at 300°C is less than 80% Evaluation B: 220°C The weight loss rate at 250°C is 20% or more, or the weight loss rate at 300°C is 80% or more. When using GTL-3 or mineral oil-3 Rating A: Weight loss rate at 220°C Less than 5%, and the weight loss rate at 250°C is less than 10%, and the weight loss rate at 300°C is less than 30%. Evaluation B: The weight loss rate at 220°C is 5% or more, or the weight loss rate at 250°C is 10% or more. Weight loss rate at 300°C is 30% or more. The evaluation results are shown in Tables 1 to 3.

(lubricity)
The lubricity of the metalworking fluids of Examples 1 to 10 and Comparative Examples 1 to 15 was measured by the Soda four-ball test and evaluated as follows.
Evaluation A: The pressure resistance of the sample is 7 kgf/cm ² or more Evaluation B: The pressure resistance of the sample is 5 kgf/cm ² or more and less than 7 kgf/cm ^{2 Evaluation C: The pressure resistance of the sample is less than 5 kgf/cm 2 The} evaluation results are shown in Table 1. Shown in 3.

As shown in Comparative Examples 7 to 10, among the metalworking fluids using mineral oil as the base oil, Comparative Examples 8 to 10 in which sulfur-based additives were added were compared to Comparative Example 7 in which sulfur-based additives were not added. Compared to this, lubricity has improved. On the other hand, in Comparative Examples 8 to 10 in which sulfur-based additives were added, the amount of oil smoke generated increased compared to Comparative Example 7 in which sulfur-based additives were not added.

On the other hand, as shown in Examples 3 to 4 and Comparative Examples 11 to 12, among the metalworking fluids using GTL as the base oil, Examples 3 to 4 and Comparative Example 12, in which sulfur-based additives were added, , the lubricity was improved compared to Comparative Example 11. Furthermore, in Comparative Example 12 in which polysulfide was added as a sulfur-based additive, the amount of oil smoke generated increased compared to Comparative Example 11 in which no sulfur-based additive was added. In Examples 3 and 4 in which ester was added, the amount of oil smoke generated did not increase much compared to Comparative Example 11 in which no sulfur-based additive was added. In particular, in Example 3 in which sulfurized oil was added as a sulfur-based additive, the amount of oil smoke generated hardly increased compared to Comparative Example 11.

The above are the results of Examples 3 to 4 and Comparative Examples 7 to 12 using GTL-3 or mineral oil-3, which have a relatively high flash point as the base oil, but GTL-3, which has a relatively low flash point as the base oil. Similar results were obtained for Examples 1 to 2 and Comparative Examples 1 to 6 in which Mineral Oil-2 or Mineral Oil-2 was used.

From the above, it has been found that metalworking fluids containing GTL and at least one of sulfurized oils and fats and sulfurized esters as sulfur-based additives have excellent lubricity and generate less oil smoke during metalworking. In other words, if sulfurized oils or sulfurized esters, among sulfur-based additives, are added to metalworking fluids that use GTL as the base oil, the amount of smoke generated during metalworking will not increase significantly, and the metalworking fluids will be improved. It was discovered that lubricity can be imparted to

Furthermore, as shown in Example 6, in metalworking fluids containing sulfurized oils and fats as sulfur-based additives, even if the content of sulfurized oils and fats is increased to 40% by mass, the sulfurized oils and fats content remains at 20% by mass. Compared to Example 3, the amount of oil smoke generated hardly increased.

Furthermore, as shown in Example 9, the amount of oil smoke generated was able to be further reduced in the metal working fluid to which calcium sulfonate was added, compared to Example 3 in which calcium sulfonate was not added.

Claims (4)

Contains 60% by mass or more and 95% by mass or less of GTL with a flash point of 190°C or higher,
A metalworking fluid characterized by containing 5% by mass or more and 40% by mass or less of sulfurized oil or fat as a sulfur-based additive. Contains 60% by mass or more and 90% by mass or less of GTL with a flash point of 190°C or higher,
A metalworking fluid containing 10% by mass or more and 30% by mass or less of a sulfurized ester as a sulfur-based additive. The metalworking fluid according to claim 1 or 2, characterized in that it contains a metal sulfonate in an amount of 2% by mass or more and 15% by mass or less. The metalworking fluid according to any one of claims 1 to 3, comprising 2% by mass or more and 15% by mass or less of zinc dithiophosphate.