JPH0940982A - Lubricating oil for metal working - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a lubricating oil for metal working which has excellent lubricity in cutting, grinding, plastic working, etc., of a metal and can offer improved treatability of wastewater by incorporating a polyalkylene oxide having a particular structure. SOLUTION: This lubricating oil for metal working comprises a compd. represented by the formula [R-O-(R'O)1 -(CH2 )m -COO]n -M (wherein R represents a 1-30C hydrocarbon radical; R' represents a 2-4-C alkylene; (1) represents an integer of 1 to 100; M represents H, an alkali metal, an alkaline earth metal, or a hydrogen ion adduct to amine; (m) represents an integer of 1 to 5; and (n) represents the valency of M). R, when the number of carbon atoms is 4 to 24, can balance hydrophilicity with lipophilicity while taking into consideration a correlation with the oxyalkylene chain (R'O)1 . This compd. is incorporated in an amt. of 0.1 to 100 pts.wt. based on 100 ptc.wt. of the total amt. of the lubricating oil. Properties can be improved by incorporating a mineral oil in an amt. of 1 to 50 pts.wt. based on 100 pts.wt. of the total amt. of the lubricating oil and this compd. in an amount of 0.5 to 25 pts.wt. based on 100 pts.wt. of the total amt. of the lubricating oil.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a lubricating oil for metalworking. The lubricating oil for metalworking of the present invention has excellent lubricity as well as good wastewater treatment.

[0002]

2. Description of the Related Art Generally, polyalkylene oxides such as polyalkylene oxides, polyalkylene oxide alkyl ethers and polyalkylene oxide alkyl esters are excellent in fluid lubrication performance, and therefore, they are mainly used as a lubricating base or a lubricant for a fluid lubrication region. It is used as an additive. An example in which the above polyalkylene oxides are applied for metal processing is disclosed in JP-A-6-10087.
No. 5, for example.

[0003]

However, in the polyalkylene oxide type lubricant, the compound actually used generally has a branched structure and the lubricity is not sufficient. This is because the boundary lubrication performance of polyalkylene oxides is poor, and in the areas such as metal cutting, grinding and plastic working where this performance is strongly required, polyalkylene oxides that exhibit excellent lubrication performance are still unobtainable. Has not been done.

Further, when polyalkylene oxides having high hydrophilicity are used, even if an aggregating agent such as a sulfuric acid band is added as a chemical agent to be used in the treatment of wastewater, the agglomeration does not occur and the treatment cannot be performed. Also has. As described above, the fact is that no polyalkylene oxide having excellent lubricity and waste water treatment property has been found. The present invention solves the above problems,
It is an object of the present invention to provide a lubricating oil for metalworking which is excellent in both lubricity and wastewater treatment by using the compound specified by the formula [1].

In order to solve the above problems, the present inventors have
As a result of diligent research on the relationship between the structure of polyalkylene oxides and the lubricity and wastewater treatability of the lubricating oil prepared using the same, the use of polyalkylene oxides having a specific structure provides excellent performance. It was found that the above lubricating oil for metal processing can be obtained, and the present invention has been completed.

[0006]

The lubricating oil for metalworking of the present invention is characterized by containing a compound represented by the following general formula [1]. _{[R-O- (R'O) l -} (CH 2) m -COO ] _n -M [1] (in the above formulas, R is a hydrocarbon group having 1 to 30 carbon atoms,
R'is an alkylene group having 2 to 4 carbon atoms, and l is 1 to 1
00 is an integer, M is a hydrogen ion addition product of hydrogen, an alkali metal, an alkaline earth metal or an amine, m is an integer of 1 to 5, and n is an integer corresponding to the valence of M. )

In the above "compound of the general formula [1]",
The above "R" is a hydrocarbon group, which may be a saturated group or an unsaturated group, such as a linear or branched alkyl group or alkenyl group. Further, it may be a compound having an aromatic ring such as an allyl group or an alkylallyl group.
These hydrocarbon groups have 1 to 30 carbon atoms and 4 to 24 carbon atoms.
Is preferred. When the carbon number exceeds 30, the lipophilicity becomes strong (hydrophobicity becomes high), the compatibility with water often used together is poor, and the liquid stability decreases. When the carbon number is in the range of 4 to 24, the oxyalkylene chain [(R '
The hydrophilicity and lipophilicity can be appropriately balanced while taking into consideration the correlation with O) _l ].

The above "R'O" is at least one of oxyethylene group, oxypropylene group and oxybutylene group. The number of moles of addition of these oxyalkylene groups is suitably 1 to 100, especially 5 to 60. When using the above compounds in lubricating oils that are not diluted with water,
The higher the hydrophobicity of “R′O”, in other words, the lower the amount ratio of oxyethylene groups, and the higher the total number of added oxyalkylene groups, the more excellent the lubricating oil can be obtained. However, even if the number of added moles exceeds 100,
The cost is high and no further improvement in performance can be seen.

In the above general formula [1], m is 5
If it exceeds, foaming occurs in the lubricating oil. This m is 1
It is preferably from 3 to 3, and within this range, there is almost no foaming, and the compound or the lubricating oil can be easily prepared. This compound is a method in which an alkylene oxide is added to an alcohol and then a carboxylic acid having a halogen element is reacted by a conventional method to form a salt, or an alkylene oxide is added to an alcohol and then oxidized to a carboxylic acid, It can be prepared by a method of converting it into a salt.

The content of the above compound in the lubricating oil for metalworking of the present invention can be in the range of 0.1 to 100 parts by weight when the total amount of the lubricating oil is 100 parts by weight.
If the content is less than 0.1 parts by weight, the lubricity is not sufficiently improved, which is not preferable. Further, in the present invention, although depending on the structure of the compound, even a dilute aqueous solution of about 0.5% by weight can provide a lubricating oil having excellent lubricity and the like. still,
The compound itself can be used as a lubricating oil without blending other components such as water.

Further, in the present invention, the total amount of lubricating oil is 1
About 1 to 50 parts by weight of mineral oil can be contained in 00 parts by weight. In this case, the content of the compound is 0.
About 1 to 30 parts by weight is preferable. If the amount of this compound is less than 0.1 part by weight, the lubricity and the wastewater treatment property due to the use of this specific compound are not sufficiently improved, and if it exceeds 30 parts by weight, the viscosity tends to be high. Can be difficult. When compounding mineral oil etc., the content of this compound is 0.5 to 25 parts by weight, especially 5 to 20 parts by weight.
The amount is preferably about parts by weight, and by using an appropriate amount of the compound while taking into consideration the structure of the compound and the like, a lubricating oil for metalworking having excellent performance can be obtained.

If the amount of the mineral oil in the lubricating oil is less than 1 part by weight, the improvement of lubricity due to the blending of the mineral oil is not sufficient.
If the amount exceeds 0 parts by weight, the stability of the oil agent decreases. The blending amount of this mineral oil is preferably 5 to 50 parts by weight, and particularly preferably 25 to 45 parts by weight. Within this range, a lubricating oil having a well-balanced lubricity and liquid stability can be obtained. As the mineral oil, those commonly used for lubricating oils for metalworking, such as paraffinic oils, naphthene oils, and aromatic oils, can be used without particular limitation.

In the formula [1], the above-mentioned "M" constituting a salt with a polyoxyalkylene monoethercarboxylic acid includes alkali metals such as sodium and potassium, alkaline earth metals such as calcium and ammonium, and monoethanolamine. And hydrogen ion adducts such as diethanolamine, triethanolamine and isopropanolamine. Of these, alkali metals such as sodium are preferred.

In addition to the above essential components, the lubricating oil for metalworking of the present invention may optionally contain oils and fats such as animal and vegetable oils, various fatty acids such as oleic acid and caprylic acid, and base oils such as higher alcohols and alkanolamines. , Chlorine-based, sulfur-based, phosphorus-based extreme pressure additives, oiliness improvers consisting of various esters, rust-inhibitors such as sorbitan monooleate and petroleum sulfonic acid, antifoaming agents such as silicone oil, higher fatty acid In addition to surfactants such as alkali metal salts and fatty acid esters of sorbitan, preservatives, dyes and the like can be appropriately added.

The lubricating oil for metalworking of the present invention can be prepared by blending and mixing the above-mentioned components as required, and the order of blending the components, the equipment used for blending, the blending method, etc., There is no limitation, and it can be usually prepared by an apparatus, a method, etc. used for preparing this type of lubricating oil.

In the lubricating oil for metalworking of the present invention, as compared with the conventional lubricating oil containing polyalkylene oxides having no carboxyl group as a lubricating component, the applicable lubricating range is
It becomes possible to extend to a more severe region, that is, a boundary lubrication region. Further, by introducing a carboxyl group (or salt), even a highly hydrophilic polyoxyalkylene alkyl (or alkenyl, allyl, alkylallyl, etc.) ether can be treated with an aggregating treatment agent, which is advantageous in wastewater treatment.

That is, in the present invention, even when a compound having a highly hydrophilic polyoxyalkylene chain is used, by introducing a carboxyl group (or salt) as described above, it aggregates with a carboxyl group or the like. Since the flocs are formed by the reaction with the treating agent, the reaction products can be removed relatively easily from the waste liquid. Furthermore,
The compound represented by the general formula [1] has both properties of a nonionic surfactant and a nonionic surfactant as a surfactant, and is also useful in terms of emulsification and solubilization of an emulsified product.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to Examples and Comparative Examples. The salt of polyoxyalkylene monoethercarboxylic acid represented by the general formula [1] was obtained as follows. Reaction product 1; polyoxyalkylene monocyclohexyl ether obtained by sequentially adding 30 moles of propylene oxide and 5 moles of ethylene oxide to 1 mole of cyclohexyl alcohol and sodium chloroacetate in the presence of sodium hydroxide, The reaction was performed under reduced pressure, and then sodium chloride produced as a by-product was removed to obtain a reaction product 1 containing 71% by weight of sodium salt of polyoxyalkylene monocyclohexyl ether carboxylic acid (Compound 1).

Reaction product 2; Polyoxyalkylene monooctyl ether obtained by sequentially adding 10 mol of propylene oxide and 10 mol of ethylene oxide to 1 mol of octyl alcohol according to a conventional method, and potassium chloroacetate were mixed with potassium hydroxide. The reaction was carried out under reduced pressure in the presence of the reaction product, and then the by-produced potassium chloride was removed to obtain a reaction product 2 containing 75% by weight of a potassium salt of polyoxyalkylene monooctyl ether carboxylic acid (compound 2).

Reaction product 3; polyoxyalkylene monostearyl ether obtained by sequentially adding 5 mol of ethylene oxide, 30 mol of propylene oxide and 5 mol of ethylene oxide to 1 mol of stearyl alcohol according to a conventional method, and potassium chloroacetate. The reaction is carried out under reduced pressure in the presence of potassium hydroxide, then by-produced potassium chloride is removed, and the potassium salt of polyoxyalkylene monostearyl ether carboxylic acid (compound 3) is added to 58%.
A reaction product 3 containing wt% was obtained.

Reaction product 4; polyoxyalkylene monostearyl ether obtained by sequentially adding 5 mol of ethylene oxide, 50 mol of propylene oxide and 5 mol of ethylene oxide to 1 mol of stearyl alcohol according to a conventional method, and sodium chloroacetate. The reaction product 4 containing 45% by weight of sodium salt of polyoxyalkylene monostearyl ether carboxylic acid (compound 4) is reacted under reduced pressure in the presence of sodium hydroxide. Obtained.

Reaction product 5: Polyoxyalkylene monostearyl ether obtained by sequentially adding 20 mol of butylene oxide and 5 mol of ethylene oxide to 1 mol of stearyl alcohol according to a conventional method and potassium chloroacetate were mixed with potassium hydroxide. Reaction product 5 containing 60% by weight of potassium salt of polyoxyalkylene monostearyl ether carboxylic acid (compound 5) after removing by-produced potassium chloride after reacting under reduced pressure in the presence of
I got

The composition of the obtained reaction product is shown in Table 1.
In Table 1, EO represents ethylene oxide, PO represents propylene oxide, and BO represents butylene oxide, and the numbers represent the number of added moles of each.

[0024]

[Table 1]

The lubricity and wastewater treatment of the five compounds in Table 1 were evaluated. Lubricity was evaluated using a reaction product stock solution containing each compound and an aqueous solution having a compound concentration of 0.5% by weight, and wastewater treatability was evaluated using an aqueous solution having a compound concentration of 0.1% by weight. The measuring method is shown below, and the results are shown in Table 2. Lubricity: The friction coefficient was measured by a Soda pendulum type oiliness tester. Wastewater treatment: Coagulation treatment using sulfuric acid band 1%, COD (unit: mg) according to the method of JIS 010218
/ L) was measured.

[0026]

[Table 2]

The comparative substance 1 in Table 2 is polyoxypropylene having a molecular weight of about 1000, and the comparative substance 2 is polyoxypropylene / oxyethylene block having a molecular weight of about 2,000 and propylene oxide / ethylene oxide (weight ratio) = 80/20. It is a copolymer.

According to the results of Table 2, in compounds 1 to 5,
The coefficient of friction of the reaction product stock solution containing them is 0.13 to
It is as small as 0.16, and it can be seen that the lubricity is extremely excellent. Further, even if the compound concentration is 0.5% by weight, it has a considerable lubricity even if it is a dilute aqueous solution. Especially, in compounds 3 to 5 using long chain alcohol, even if it is a dilute aqueous solution, It can be seen that it has the same level of lubricity as the stock solution of the comparative substance. In addition, these compounds, particularly compounds 4 to 5
Also has very good performance in wastewater treatment.

On the other hand, in the case of the comparative substance, the lubricity of the stock solution is comparable to that of the above compounds, but in the dilute aqueous solution, the friction coefficient becomes very large, and it is understood that sufficient performance cannot be obtained unless the concentration is high. Further, the wastewater treatment property is very poor, and the COD is as high as about 2 to 3 times that of the compounds 1 to 3 and about 10 times that of the compounds 4 to 5.

Next, a lubricating oil obtained by blending a reaction product containing each compound of Table 1 with each component of Table 3 in a predetermined amount was prepared, and a stock solution of the formulation and a 5 wt% aqueous solution thereof were prepared as described above. The lubricity was evaluated in the same manner as in. The results are shown in Table 4. The comparative substance used in Comparative Example 2 was
It is a potassium salt of castor oil with 24 moles of oxyethylene added to the hydroxyl group.

[0031]

[Table 3]

[0032]

[Table 4]

According to the results of Table 4, in Examples 1 to 5,
Compared with the case where the reaction product containing the above compound was used alone, the friction coefficient tended to be slightly smaller, and it can be seen that a lubricating oil having more excellent lubricity was obtained. Even when the stock solution of these compounds was made into a 5% by weight aqueous solution, the friction coefficient hardly changed.
It can be seen that a lubricating oil having sufficient performance can be obtained with an aqueous solution having a low concentration. In addition, in Example 5, since 38 parts by weight of mineral oil was used, the lubricity was the best, but it is expected that the wastewater treatability would be slightly deteriorated. The lubricating oil for use can be a lubricating oil in which the lubricity and the wastewater treatment property are appropriately balanced.

On the other hand, it can be seen that the lubricating oil of Comparative Example 1 containing neither the above compound nor mineral oil has a very large friction coefficient and is inferior in lubricity. Further, in the case of Comparative Example 2 in which 20 parts by weight of the comparative substance was blended, the lubricity was good in the undiluted solution, but there was a tendency of a slight decrease in the 5% aqueous solution. Furthermore,
The lubricating oil of Experimental Example 1 using a large amount of 49 parts by weight of mineral oil has excellent lubricity, but the lubricating oil containing the specific compound of the present invention also lubricates using this mineral oil. It can be seen that it has a performance comparable to that of oil.

[0035]

INDUSTRIAL APPLICABILITY In the lubricating oil for metalworking of the present invention, by using a specific carboxylic acid or a salt thereof, it is possible to obtain a lubricating oil for metalworking which is excellent in lubricity and also has a good wastewater treatment property. You can

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical indication location C10N 40:20 (72) Inventor Kenji Rakutani 10-12 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa (72) Inventor Kunihiko Kiseshi 10-12 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Stock company

Claims (1)

[Claims] 1. A lubricating oil for metalworking, comprising a compound represented by the following general formula [1]. _{[R-O- (R'O) l -} (CH 2) m -COO ] _n -M [1] (in the above formulas, R is a hydrocarbon group having 1 to 30 carbon atoms,
R'is an alkylene group having 2 to 4 carbon atoms, and l is 1 to 1
00 is an integer, M is a hydrogen ion addition product of hydrogen, an alkali metal, an alkaline earth metal or an amine, m is an integer of 1 to 5, and n is an integer corresponding to the valence of M. )