JPH0225957B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-based lubricating oil composition used for water-containing hydraulic oils, metal working oils, and the like. Conventionally, water-based lubricating oils have often been used as hydraulic oils, metal working oils, etc. for the purpose of preventing fires caused by lubricating oil leaks. Water-based lubricating oils, such as water-glycol flame-retardant hydraulic oils and solution-type cutting oils, generally contain water-soluble polymeric compounds such as polymethacrylates, etc. as lubricity improvers or thickeners. Contains about 5 to 40% by weight of polyethers. However, in recent years, from the viewpoint of resource and energy conservation, there has been an increasing demand for water-based lubricating oils with significantly increased water content. This requirement is particularly remarkable for water-glycol type flame-retardant hydraulic oils, and a high water content type hydraulic oil with a water content of about 85 to 95% is now required, compared to the conventional water-based hydraulic oils with a water content of about 40%. Water - The amount of water in glycol-based flame-retardant hydraulic oil is 85
Increasing the content of thickeners to about 95% will inevitably reduce the content of thickeners in water-based hydraulic fluids, which can no longer be addressed by the thickeners conventionally used. . In other words, polysodium methacrylate, which has a thickening effect when added in small amounts, and polyethylene oxide, which has a molecular weight of several hundred thousand to several million, are weak against mechanical shear stress.
During use, the molecular weight decreases significantly due to molecular cleavage, that is, the viscosity decreases, making it unsuitable as a thickener for water-based hydraulic fluids. On the other hand, water-soluble polyethers with a molecular weight of 50,000 or less, which are currently mainly used as thickeners for water-glycol flame-retardant hydraulic fluids, are stable against mechanical shear stress, but have a small thickening effect. Therefore, when added in small amounts, the viscosity does not increase, resulting in poor lubricity and large leakage of hydraulic fluid from joints of parts of working machines, making it unsuitable as a thickener for water-based hydraulic fluids. As a result of intensive research to obtain a water-based lubricating base that is stable against mechanical shear stress and has a large thickening effect, the present inventors identified a different type of polyether with a special structure. The inventors have discovered that excellent shear stability and thickening effect can be obtained by using the ratio of . That is, the present invention provides a water-based lubricating oil composition containing a polyether compound represented by the following formula [] and a polyether compound represented by the formula [] or []. R ₁ Y [(C ₂ H ₄ O) _k (C _p H _2p O) _l H] _a … [] [R ₂ O (C ₂ H ₄ O) _n (C _p H _2p O) _o ] ₂ CH ₂ ... [] R ₃ Y [(C ₂ H ₄ O) _n (C _p H _2p O) _o R ₄ ] _a ... [] (Here, R ₁ , R ₂ , R ₃ , and R ₄ are the carbon numbers 5 to 26 hydrocarbon groups, p is an integer of 3 to 4, k+l is 2
or 200, l may be 0, and the ratio of k/l is 3/7 or more, m+n may be 10 or 200, and n may be 0, and the ratio of m/n is 3/7 or more. , Y is an oxygen atom or a nitrogen atom,
When Y is an oxygen atom, a is 1, and when Y is a nitrogen atom, a is 2. ) The polyether compound of the formula [ ] used in the present invention is an aliphatic saturated alcohol having 5 to 26 carbon atoms,
Starting materials include aliphatic unsaturated alcohols, alicyclic alcohols, aromatic alcohols, alkyl-substituted phenols, alkenyl-substituted phenols, aliphatic saturated amines, aliphatic unsaturated amines, alicyclic amines, aromatic amines, etc. Ethylene oxide alone or together with ethylene oxide having 3 to 4 carbon atoms
It is obtained by random or block polymerization of alkylene oxide. The polyether compound of the formula [] or [] is prepared by converting the hydrogen of the terminal hydroxyl group of the polyalkylene glycol monoalkyl ether shown by the formula [] to sodium with metallic sodium, etc., and then reacting it with a mono- or dihalogenated alkyl compound. obtained by Examples of the alcohols, phenols, and amines used as starting materials include pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, and heptadecanol. , octadecanol, nonadecanol, cyclopentanol, cyclohexanol, benzyl alcohol, cinnamyl alcohol, oleyl alcohol, octylphenol, nonylphenol, decylamine, dodecylamine, tridecylamine, pentadecylamine, hexadecylamine, heptadecylamine , octadecylamine,
Examples include oleylamine. Examples of alkylene oxides having 3 to 4 carbon atoms include propylene oxide (hereinafter referred to as PO), butylene oxide (hereinafter referred to as BO), and tetrahydrofuran (hereinafter referred to as THF). In the polyether compound of formula [], formula [] or formula [], the ratio k/l and m/n of ethylene oxide and other alkylene oxide is 3/
The reason why it is limited to the range of 7 or more is because if it is less than 3/7, the water solubility is poor and it cannot be used as a water-based lubricating oil. The reason why the number of carbon atoms in the starting compound to which alkylene oxide is added is limited to a range of 5 to 26 is that if it is less than 5, the hydrophobicity of the starting compound is small, and even if the alkylene oxide is added, the balance between hydrophobicity and hydrophilicity will be imbalanced. This is because they do not match and do not exhibit a thickening effect. The reason why the number of moles of alkylene oxide added k+l and m+n of the compound of formula [], [] or [] is limited to the ranges of 2 to 200 and 10 to 200, respectively, is that less than 2 or 10 moles, respectively, has poor water solubility. This is because it cannot be used as a water-based lubricant. Moreover, if it exceeds 200 mol, water solubility becomes too strong and no thickening effect is exhibited. The water-based lubricating oil composition of the present invention is characterized by the use of a combination of a compound of the formula [] and a compound of the formula [] or a compound of the formula [], and its preferred composition is 0.1 to 30% by weight of the compound of the [] formula; 0.1 to 30% by weight of the formula [] or the compound of the formula [], and 40 to 99.8% by weight of water. When using the formula compound alone, the thickening effect is highly temperature dependent; it shows a thickening effect only near the cloud point temperature of the aqueous solution, below that temperature no thickening effect is observed, and above that temperature. It separates and is of no practical use. On the other hand, compounds of formula [] or [] alone exhibit a thickening effect over a wide temperature range, but they are not stable in aqueous solutions and separate over time, making them unsuitable as base materials for lubricating oils. . However, a combination of a compound of the formula [] and a compound of the formula [] or [] does not exhibit any of the drawbacks of the single compound described above, and exhibits excellent performance as a base for water-based lubricating oils. In the water-based lubricating oil composition of the present invention, if lubricity is particularly required, good results can be obtained by further blending a water-soluble compound with a number average molecular weight of 500 to 10,000. In this case, the preferred blending composition is 0.1 to 30% by weight of the compound of formula [], 0.1 to 30% by weight of the compound of formula [] or [], 0.1 to 10% by weight of the above water-soluble compound, 30 to 30% by weight of water.
It is 99.7% by weight. Particularly preferred formulation examples are []
1 to 15% by weight of a compound of formula [] or []
1 to 15% by weight of a compound of the formula above, water-soluble compound 1
5% to 5% by weight water, 65% to 97% by weight. Examples of the water-soluble compounds having a number average molecular weight of 500 to 100,000 include polyacrylates, maleic acid copolymer salts, polyacrylamide, polyethyleneimine, water-soluble urea resins, polyvinyl alcohol,
There are polyether derivatives, etc., but [formula], []
Polyether derivatives, particularly polyoxyalkylene glycols, which have a strong affinity with the formula or the compound of formula [] are preferred. The aqueous lubricating oil composition of the present invention may further contain various commonly used additives such as extreme pressure agents, oiliness improvers, antifoaming agents, and antioxidants, if necessary. The water-based lubricating oil composition of the present invention exhibits excellent viscosity properties in a wide temperature range, has excellent shear stability and storage stability of aqueous solutions, and is used in many applications such as hydraulic oil, drawing oil, cutting oil, press oil, etc. It can be used for various purposes. Furthermore, since the base material used in the present invention exhibits sufficient lubricating properties even when mixed in a small amount, the water content is 85% by weight.
Even when using the above-mentioned high water content type hydraulic oil, sufficient high performance can be exhibited. Hereinafter, the present invention will be explained in Examples. Production Example 1 270 g (1 mole) of n-octadecyl alcohol and 6 g of potassium hydroxide as a catalyst were placed in a 4-volume airtight reaction vessel, and 2329 g (53 mole) of ethylene oxide and 406 g of propylene oxide were added in a nitrogen gas atmosphere.
(7 mol) of the mixture was randomly polymerized at 90 to 130°C under pressure of 0.5 to 5.0 Kg/cm ² to obtain 3000 g of polyoxyethylene propylene glycol monooctadecyl ether (crude reaction product). After neutralizing the potassium hydroxide in this crude reaction product with an aqueous hydrochloric acid solution, it was dehydrated for 2 hours at 80 to 120°C under a reduced pressure of 50 mmHg or less, and the precipitated salt was separated, resulting in 2950 g of purified reaction product.
I got it. Production Example 2 1503 g (0.5 mol) of the purified reactant synthesized in Production Example 1 and 23 g of metallic sodium were placed in a 2-volume airtight reaction vessel.
(1 mol) was taken and a sodium conversion reaction was carried out for 10 hours at 80 to 120°C and under reduced pressure of 50 mmHg or less.
21.3 g (0.25 mol) of dichloromethane was pressurized into a reaction vessel under nitrogen pressure, and a coupling reaction was carried out at 80 to 130°C for 10 hours to obtain 1020 g of polyoxyethylene propylene glycol dioctadecyl ether (crude reaction product). Obtained. This crude reaction product was purified in the same manner as in Production Example 1, and the purified reaction product was
Obtained 950g. Below, in accordance with Production Example 1 and Production Example 2,
The compounds described in each Example of 1 were obtained. Example 1 A water-based lubricating oil composition was prepared by mixing the compounds shown in the sample numbers in Table 1 according to their compositions. Table 1 shows test results of the cloud point, thickening effect, storage stability, and shear stability of the products of the present invention and comparative products. As is clear from the results in Table 1, when the formula compounds (Samples No. 8, No. 9, and No. 10) were used alone, the cloud point was low even when the viscosity was increased, and it remained at room temperature. If a compound that is separated and has a high cloud point is used, it is unsuitable as a base for water-based lubricating oils because it has drawbacks such as no thickening effect. On the other hand, [] expression or []
When the formula compound (Sample No. 11, No. 12) is used alone, it has an excellent thickening effect, but the stability of the aqueous solution is poor and it separates over time, so it is not suitable as a base for water-based lubricating oil. It is inappropriate. However, the product of the present invention, which is a combination of both compounds, can eliminate all the drawbacks of using both compounds alone.
Furthermore, the product of the present invention can be applied to existing high molecular weight thickeners (sample
Unlike No. 13), there is no viscosity drop due to shear stress, making it an excellent water-based lubricating oil composition.

【table】

【table】

[Table] ○: Completely transparent, △: Fluorescent or turbid ×: Separated 3) Shear stability: Measured with an ultrasonic shear stability tester (output 150W, frequency 10KC)
Measurement conditions: Irradiation time 60
Minutes Temperature 40℃
η ₂ η ₁ :
Kinematic viscosity at 25℃ before ultrasonic irradiation
Shear stability =

Claims (1)

[Claims] 1. A water-based lubricating oil composition containing a polyether compound represented by the following formula [] and a polyether compound represented by the formula [] or []. R ₁ Y [(C ₂ H ₄ O) _k (C _p H _2p O) _l H] _a … [] [R ₂ O (C ₂ H ₄ O) _n (C _p H _2p O) _o ] ₂ CH ₂ ... [] R ₃ Y [(C ₂ H ₄ O) _n (C _p H _2p O) _o R ₄ ] _a ... [] (Here, R ₁ , R ₂ , R ₃ , and R ₄ are the carbon numbers 5 to 26 hydrocarbon groups, p is an integer of 3 to 4, k+l is 2
or 200, and l may be 0, and the ratio of k/l is 3/7 or more, and m+n is 10 or 200, and n is 0.
In some cases, the m/n ratio is 3/7 or more, and Y
is an oxygen atom or a nitrogen atom; when Y is an oxygen atom, a is 1; when Y is a nitrogen atom, a is 2. 2. The water-based lubricating oil composition according to claim 1, comprising 0.1 to 30% by weight of a compound of formula [], 0.1 to 30% by weight of a compound of formula [] or [], and 40 to 99.8% by weight of water. 3. The water-based lubricating oil composition according to claim 1, further comprising a water-soluble compound having a number average molecular weight of 500 to 100,000. 4. A patent consisting of 0.1 to 30% by weight of a compound of formula [], 0.1 to 30% by weight of a compound of formula [] to [], 0.1 to 10% by weight of a water-soluble compound with a number average molecular weight of 500 to 100,000, and 30 to 99.7% by weight of water. The water-based lubricating oil composition according to claim 3. 5. The water-based lubricating oil composition according to claim 3 or 4, wherein the water-soluble compound is polyoxyalkylene glycol. 6. The water-based lubricating oil composition according to claim 2 or 4, which is a highly water-containing hydraulic oil having a water content of 85% by weight or more.