JP2001139974A - Lubricant composition for metal-processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a metal-processing lubricant composition that includes no chlorine compound, maintains fluid stability even when a superbase metal sulfonate is applied, and performs excellent lubricity in metal processings, for example, cutting and grinding. SOLUTION: The objective lubricant composition for metal processing comprises, when the whole amount of the metal-processing lubricant composition is counted as 100 pts.wt.: (a) 0.5-70 pts.wt. of a superbase metal sulfonate of an alkali metal and/or an alkaline earth metal (b) 5-80 pts.wt. of an ester from a monohydric alcohol and a monocarboxylic acid; in which the acid value of the ester as the component (b) is <=1 mgKOH/g and the TBN of (a) the superbase metal sulfonate is >=300 mgKOH/g characteristically.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil composition for metalworking, and more particularly to a lubricating oil composition for metalworking which does not contain any chlorine-based additive and which has excellent liquid stability and is excellent in cutting, grinding or plastic working. The present invention relates to a metalworking composition that can exhibit lubricity.

[0002]

2. Description of the Related Art Conventionally, extreme pressure additives such as sulfur, chlorine and phosphorus have been added to lubricating oils for metal working used for cutting or grinding metals for the purpose of imparting lubricity. Among them, chlorinated compounds such as chlorinated paraffins and chlorinated fatty acid esters are inexpensive compared to other extreme pressure additives and have excellent lubrication performance, so in metal cutting or grinding, Conventionally, lubricating oil compositions for metalworking containing a large amount of chlorine compounds have been used.

[0003] However, regarding chlorinated compounds, for example, in the United States, certain chlorinated paraffins are recognized as carcinogenic substances, and furthermore, a warning of carcinogenicity is required by the enforcement of the PL law, and human health is required. Problems were pointed out. Further, when incinerating a waste liquid of a cutting or grinding lubricating oil containing a chlorine-based compound, hydrogen chloride (HCl), which causes air pollution during combustion, is generated, or
It has recently been pointed out that there is a possibility that environmental pollution may be caused due to generation of dioxin depending on the combustion temperature at the time of incineration. Given these circumstances,
In many countries, the use of metalworking fluids containing chlorinated paraffins is being shunned.

[0004] Therefore, the development and study of lubricating oil compositions for metal working which do not contain chlorinated compounds such as chlorinated paraffins have been studied. Such lubricating oil compositions for metal working include sulfur-based, phosphorus-based, and lubricating oil compositions. A lubricating oil composition for metalworking containing an organometallic or overbased metal sulfonate or the like has been studied. Among these, overbased metal sulfonates are particularly promising as an alternative to chlorinated additives because of their good lubricity, but overbased metal sulfonates include oils and fats, esters of polyhydric alcohols and fatty acids, and the like. When used in combination with the oily agent, there is a problem that the stability of the lubricating oil composition is reduced.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and does not include chlorine-based compounds that may affect the environment and health, and uses an overbased metal sulfonate. Has excellent liquid stability,
An object of the present invention is to provide a lubricating oil composition for metal working that exhibits excellent lubricity in metal working such as grinding.

[0006]

Means for Solving the Problems The present inventors have intensively studied the liquid stability of an overbased metal sulfonate, and as a result, by using an overbased metal sulfonate and a synthetic ester having a specific acid value in combination, In metal processing,
The present inventors have found that a lubricating oil composition for metalworking that exhibits excellent lubricating properties without containing a chlorine-based compound and also has excellent liquid stability can be obtained, thereby completing the present invention. That is, the lubricating oil composition for metalworking of the first invention comprises (a) an overbased metal sulfonate with an alkali metal and / or an alkaline earth metal, and (b) an ester of a monohydric alcohol and a monocarboxylic acid. It is characterized in that the ester contained as the component (b) has an acid value of 1 mgKOH / g or less.

The above-mentioned "(a) overbased metal sulfonate of an alkali metal or alkaline earth metal (hereinafter simply referred to as" component (a) ") in the first invention is a metal salt of an organic sulfonic acid, a basic alkali metal salt. It is an oil-soluble dispersion (basic organic / inorganic dispersion) composed of an earth metal salt and an organic solvent. The alkali metal constituting the component (a) includes sodium and potassium, and the alkaline earth metal includes calcium, barium, magnesium and the like. Of these, calcium salts are particularly preferred.
These may be used alone or in combination of two or more. Further, the total base number (TBN) of the component (a) in the first invention is usually 300 mgK
OH / g or more, preferably 350 mgKOH / g or more,
More preferably, it is 500 mgKOH / g or more. When the value of TBN is less than 300 mgKOH / g, it is not preferable because the machinability is poor.

The monohydric alcohol constituting the above-mentioned "(b) ester of monohydric alcohol and monocarboxylic acid" (hereinafter, simply referred to as "component (b)") in the first invention is branched even if it is a linear alcohol. Alcohol may be used and usually has 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms.
A hydric alcohol is used. If the number of carbon atoms exceeds 20, the melting point becomes high and the use becomes difficult, which is not preferable.
The monocarboxylic acid may be a straight-chain carboxylic acid or a branched carboxylic acid. Usually, a monocarboxylic acid having 8 to 20, preferably 12 to 18 carbon atoms is used. When the number of carbon atoms is less than 8, the odor is strong, which is not preferable. On the other hand, when the number is more than 20, the melting point becomes high, and it becomes difficult to use.

The acid value of the ester (b) is usually 1 mg KOH / g or less, preferably 0.7 mg KOH / g or less.
KOH / g or less, more preferably 0.5 mg KOH / g
It is as follows. If the acid value of this ester exceeds 1 mgKOH / g, a metal salt is easily formed, the liquid stability becomes poor, and the lubricating property becomes poor.

The content of the components (a) and (b) in the first invention is not particularly limited, but usually, as shown in the second invention, the total amount of the lubricating oil composition for metal working is 100%. In the case where the amount is (b), the content of the component (a) is usually 0.5 to 70 parts by weight, preferably 2 to 50 parts by weight, more preferably 5 to 50 parts by weight.
The content of the component is usually 5 to 80 parts by weight, preferably 5 to 7 parts by weight.
0 parts by weight, more preferably 5 to 50 parts by weight. If the content of the component (a) is less than 0.5 part by weight, the machinability is poor, which is not preferable. On the other hand, if the content exceeds 70 parts by weight, the viscosity of the lubricating oil composition for metal working becomes high and is supplied to the processing site. This is not preferable because it makes it difficult to perform the operation. Further, if the content of the component (b) is less than 5 parts by weight, the machinability is poor, which is not preferable. On the other hand, if the content is more than 80 parts by weight, the liquid stability particularly at low temperatures (0 ° C. or lower) is not preferable.

The base oil of the lubricating compositions for metal working of the first and second inventions is not particularly limited as long as it is usually used for lubricating oils for metal working. Such base oils include, for example, mineral oil, mineral oil in which sulfur powder is dissolved, and synthetic oils (polyalphaolefin, alkylbenzene, alkylnaphthalene, boribene, polyoxyalkylene glycol, polyoxyalkylene glycol ether,
Silicone oil, polyol ester, etc.).

The lubricating oil composition for metalworking of the present invention is excellent in lubricity without containing a chlorine-based additive, and has a cutting resistance of 3250 N measured by the conditions and measuring methods described in the following examples. Or less, preferably 3200 N or less, more preferably 3100 N or less, and the processed surface roughness can be 14 μm or less, preferably 11 μm or less, more preferably 10 μm or less.

The lubricating oil compositions for metalworking of the first and second inventions are usually used in order to maintain the basic performance of the lubricating oil composition for metalworking in addition to the above-mentioned components. Various additives can be appropriately added as needed as long as the purpose of the present invention is not impaired. For example, extreme pressure additives (sulfur-based, phosphorus-based [zinc dialkyldithiophosphate, etc.]),
An antioxidant, a rust preventive, an anticorrosive, and the like can be appropriately added.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described with reference to examples and comparative examples. (1) Preparation of lubricating oil composition for metal working By mixing the following components in parts by weight shown in Tables 1 and 2, lubricating oil compositions for Examples 1 to 6 and Comparative Examples 1 to 4 were prepared. An oil composition was prepared. (A) Overbased metal sulfonate Overbased Ca sulfonate: trade name "Lubrizo1"
5347 ", manufactured by Japan Lubrizol Co. (b) Ester methyl oleate (acid value: 0.2 mg KOH / g) Rapeseed oil: trade name" rapeseed oil "manufactured by Toei Chemical Co., Ltd. (acid value: 2 mg KOH / g) (c) Other Ingredients Soybean oil: trade name "Soybean oil", manufactured by Toei Chemical Co., Ltd. Mineral oil: trade name "spindle oil", Cosmo Oil Co., Ltd. polysulfide: tradename "DAILUBE GS44"
0 ", manufactured by Dainippon Ink and Chemicals, Inc. Chlorinated paraffin: trade name" Empara K-50 ", manufactured by Ajinomoto Fine Techno Co., Ltd.

(2) Performance evaluation of lubricating oil composition for metal working In order to clarify the performance of the lubricating oil composition for metal working of the present invention, each metal working of Examples 1 to 11 and Comparative Examples 1 to 7 was carried out. The following performance tests were performed using the lubricating oil composition for use. Liquid Stability Each of the metal working lubricant compositions of Examples 1 to 5 and Comparative Examples 1 to 3 was allowed to stand at 50 ° C. for 48 hours, and visually examined for liquid separation or turbidity. The results are shown in Table 1 below. In Table 1, “○” indicates that neither separation nor turbidity of the liquid was observed, and “X” means that separation or turbidity of the liquid was observed.

[0016]

[Table 1]

Evaluation of Performance of Lubricating Oil Composition for Metalworking Using the lubricant compositions for metalworking of Examples 6 to 11 and Comparative Examples 4 to 7, a work material (chromium steel [SCr420
H]), a surface broach test was performed using a Fujikoshi testing machine under the following test conditions, and the cutting resistance (N) and the processed surface roughness (μm, Rz) when cutting were measured. The results are shown in Table 2 below. Tool: SKH55 (6 blades, rake angle 15 °, clearance angle 2
°, blade width 4 mm), depth of cut: 0.08 mm / blade, cutting speed: 4 m / min The cutting resistance was measured using a piezoelectric dynamometer manufactured by Kistler, and the surface roughness was Surfcom (manufactured by Tokyo Seimitsu). It measured using.

[0018]

[Table 2]

(3) Effects of the Examples According to Table 1, the lubricating oil compositions for metal working of Examples 1 to 5 containing both the components (a) and (b) have excellent liquid stability. Whereas, Comparative Example 2 containing no component (b), the acid value of the component (b) was 1 mgKOH / g
It can be seen that in each of the lubricating oil compositions for metal working of Comparative Examples 1 and 3, which exceed the above, turbidity and separation of the liquid are caused. From this, the above components (a) and (b)
It can be seen that the liquid stability can be improved by not only using the component in combination but also setting the acid value of the component (b) to 1 mgKOH / g or less.

From Table 2, it can be seen that each of the metal working lubricating oil compositions of Comparative Example 4 containing no component (a) and Comparative Example 5 containing no component (b) had a cutting resistance of 3419 N. And 3596N, the lubricity is quite poor,
As a result, the work surface roughness of the work material was 15.2 μm each.
And 19.6 μm, which is considerably coarse. Similarly, the acid value of the component (b) is 1 mgKOH / g
In the lubricating oil composition for metal working of Comparative Example 6 that exceeds
The appearance of the lubricating oil composition for metal working becomes turbid, the cutting resistance becomes 3398 N, the processed surface roughness becomes 14.6 μm,
It can be seen that the lubricity is still poor and the processed surface is rough.

On the other hand, both (a) component and (b) component are contained, and the acid value of (b) component is 1 mgKOH / g
The following metal working lubricating oil compositions of Examples 6 to 11 have excellent cutting properties of 2946 to 3247 (N), excellent lubricity, and have a work surface roughness of 6.3 to 12 for the work material. .9
(Μm), which indicates that the surface properties of the work material are also quite excellent. In addition, these Examples 6-1
Each of the metalworking lubricating oil compositions of No. 1 shows almost the same cutting resistance and machined surface roughness as compared with Comparative Example 7 which is a conventional metalworking lubricating oil composition containing chlorinated paraffin. Therefore, it can be seen that excellent lubricity and surface workability can be obtained even without using a chlorine compound.

In the present invention, the present invention is not limited to the specific embodiments described above, but may be variously modified within the scope of the present invention in accordance with the purpose and application. That is,
The lubricating oil composition for metalworking of the present invention is not limited to the compositions and mixing ratios shown in Table 1, but may be various compositions and mixing ratios within the scope of the present invention.

[0023]

According to the lubricating oil composition for metalworking of the present invention, it does not contain a chlorine-based compound, has excellent liquid stability even when an overbased metal sulfonate is applied, and has a high metal stability for cutting and grinding. Excellent lubricity in processing. As a result, it is possible to incinerate without substantially affecting the environment and health, and with excellent lubricity, metal processing can be performed efficiently and, furthermore, since it has excellent liquid stability, Lubricating oil handling becomes easier.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) (C10M 111/06 (C10M 111/06 109: 00 109: 00 105: 34) 105: 34) C10N 10: 02 C10N 10:02 10:04 10:04 30:00 30:00 Z 30:04 30:04 40:22 40:22 40:24 40:24 Z (72) Inventor Nobuomi Kuroi Samukawa, Koza-gun, Kanagawa 1580 Machidabata F-term in Yushiro Chemical Industry Co., Ltd. (reference) 4H104 BB32A BB32C DA02A DB07C EA22A EB02 FA01 FA02 LA02 LA20 PA21

Claims (2)

[Claims] 1. The composition according to claim 1, further comprising (a) an overbased metal sulfonate of an alkali metal and / or an alkaline earth metal, and (b) an ester of a monohydric alcohol and a monocarboxylic acid, and the component (b). The acid value of the ester is 1
A lubricating oil composition for metalworking, which is not more than mgKOH / g. 2. When the total amount of the lubricating oil composition for metal working is 100 parts by weight, the content of the component (a) is 0.5 to 0.5 parts by weight.
The lubricating oil for metalworking according to claim 1, wherein 70 parts by weight and the content of the component (b) are 5 to 80 parts by weight.