JPS6324039B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a water-based lubricating oil composition, particularly a water-based lubricating oil composition that has low foaming properties and is used as a water-soluble hydraulic oil, a heat transfer medium, a metal working oil, and the like. Traditionally, water-insoluble flammable lubricants based on mineral oils or animal and vegetable oils have been used as hydraulic fluids, heat carriers, metal processing oils, etc., but in recent years, efforts have been made to prevent fires from occurring due to oil leaks. Water-based lubricating oils have come to be used for the purpose of preventing metal processing oils, and because the used processing oils can be easily removed from metal surfaces by washing with water. For such water-based lubricating oils, water-soluble polymer compounds are generally used to improve lubricity and increase viscosity. Known examples of the above-mentioned water-soluble polymer compounds include polyvinyl alcohol, polymethacrylates, cellulose derivatives, and polyoxyalkylene compounds. In particular, polyoxyalkylene compounds have a low pour point as a synthetic lubricant, have excellent viscosity characteristics, are chemically stable, generate little sludge or varnish, have excellent shear stability, and are useful for various metals. It has the advantage of not corroding or eroding sealing materials such as rubber and rubber. However, existing polyoxyalkylene compounds have many drawbacks, such as poor oxidation stability at high temperatures, easy thermal decomposition, poor lubricity due to poor wetting of metal surfaces, and high foaming properties. The present inventors conducted intensive research to improve the drawbacks of existing polyoxyalkylene compounds as synthetic lubricating oils, and as a result, they discovered a polyoxyalkylene glycol compound with a special molecular structure and arrived at the present invention. That is, the present invention is a water-based lubricating oil composition containing a polyoxyalkylene glycol compound of the following formula (1) or (2). [R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 4 carbon atoms, X is an oxygen atom or a nitrogen atom, and Y is a carbon number 1
~4 alkylidene group, AO has 3 or 4 carbon atoms
oxyalkylene group, EO is oxyethylene group,
n is an integer of 1 or 2, and a and b are each from 10 to
500, c is 1 to 50, and the ratio of b/(a+b) is
The range is from 25/75 to 95/5, and the numbers in parentheses are those obtained by first randomly polymerizing a mole of AO and b moles of EO, and then block polymerizing c moles of AO at the end. ] The polyoxyalkylene glycol compound of formula (1) or (2) used in the present invention uses alkylidene bisphenols, alkylidene bisanilines, alkylidene biscyclohexanols, alkylidene biscyclohexylamines, etc. as starting materials, This was obtained by random polymerization of a predetermined amount of AO and EO, and further block polymerization of a predetermined amount of AO. Examples of the above starting material compounds include bisphenol A (4.4'-isopropylidene diphenol), hydrogenated bisphenol A (4.4'-isopropylidene dicyclohexanol), 4.4'-butylidene-bis-(6 -tertiarybutyl-3-methylphenol), 4.4'-diaminodiphenylmethane, and 4.4'-diaminodicyclohexylmethane. As AO, propylene oxide (hereinafter PO
), 1,2-butylene oxide, 2,3-butylene oxide, isobutylene oxide and tetrahydrofuran. In the polyoxyalkylene glycol compound of formula (1) or (2), the number of moles a of AO added and the number b of moles of EO added in the random polymerization part are each 10
~500 is preferred; if a and b are less than 10, the molecular weight is too low and it is difficult to obtain a lubricating oil viscosity;
If it exceeds 500, shear stability deteriorates. In addition, the number c of added moles of AO in the block polymerization part is preferably 1 to 50, and in order to have low foaming, c must be at least 1 or more, and if it exceeds 50, the hydrophobicity becomes strong. If it is too much, the water solubility decreases, which is undesirable. Also, the ratio of the number of moles of EO to total AO b/(a+c)
is limited to the range of 25/75 to 95/5.
If it is less than 75, it has poor water solubility and cannot be used as a water-based lubricant.If it exceeds 95/5, it has good water solubility, but its freezing point becomes high, and even if it is used dissolved in water, it may not be used as a water-based lubricant. This is because it is not preferable because it solidifies at room temperature. The polyoxyalkylene glycol compound of formula (1) or (2) used in the present invention has good thermal stability and oxidative stability because alkylidene bisphenyl groups and alkylidene This is because it has a bisanilino group, or a chemically stable alkylidene biscyclohexyl group, alkylidene biscyclohexylamino group, etc. in the molecule, and the reason why it has good lubricity is because it has the aforementioned lipophilic group in the molecule. This is thought to be due to improved wetting of the metal surface. The reason why the polyoxyalkylene glycol compound used in the present invention has good antifoaming properties in an aqueous solution is (1)
It is related to the structure of formula or formula (2), and has a hydrophilic group consisting of a random polymer of an oxyalkylene group and an oxyethylene group on both sides of the aforementioned lipophilic group,
Furthermore, it has a unique molecular structure consisting of a block polymer of lipophilic oxyalkylene groups at the end. The water-based lubricating oil composition of the present invention is a liquid mixture of 4 to 8% by weight of a polyoxyalkylene glycol compound of formula (1) or (2) (hereinafter referred to as base oil) and 20 to 96% by weight of water. If necessary, a water-soluble organic solvent may be added in an amount of 0 to 50% by weight. A particularly preferred formulation is as follows: base oil 8-50% by weight, water 20-50% by weight.
% by weight, water-soluble organic solvent 20-50% by weight. Furthermore, if necessary, various commonly used additives may be added to improve extreme pressure properties, lubricity, rust prevention, antioxidation, antifoaming properties, and the like. Examples of the water-soluble organic solvent include glycols such as ethylene glycol, diethylene glycol, propylene glycol, and dipropylene glycol; and monoalkyl ethers of these glycols (alkyl groups having 1 to 6 carbon atoms); glycerin, trimethylol; Polyhydric alcohols such as propane, pentaerythritol, and sorbitol; and polyoxyethylene or polyoxypropylene adducts of these glycols, glycol monoalkyl ethers, and polyhydric alcohols (with an average molecular weight of 700 or less), etc. included. The base oil used in the present invention has characteristics such as good thermal stability, oxidation stability, and lubricity, is easily dissolved in water, and its aqueous solution has low foaming properties. Water-based lubricating oil compositions are extremely useful as hydraulic oils, heat carriers, and metal working oils such as quenching oils, drawing oils, grinding oils, and press oils. Next, production examples of the base oil used in the present invention and examples of the present invention will be shown. Production Example 1 Each compound shown in Table 1 was produced as follows, and the characteristic values (hydroxyl number, average molecular weight, kinematic viscosity, pour point, cloudy point) of each compound were measured, and the state of the aqueous solution was determined. Examined. The results are shown in Table-1. Manufacture of compound Bisphenol A 22.8Kg in an airtight reaction vessel
(100 mol) and 165 g of potassium hydroxide as a catalyst, EO35.2Kg (800 mol) was prepared under nitrogen gas atmosphere.
and PO8.8Kg (150mol) at 90℃~130℃,
Random addition polymerization was carried out under pressure of 0.5 to 5.0 Kg/cm ² to obtain 66.5 Kg of bisphenol A polyoxyethylene propylene glycol (crude reaction product). Next, 6.65Kg of the crude reactant was placed in an airtight reaction vessel, and under the same conditions, EO42.7Kg (970 mol) and PO10.6Kg were added.
(183 mol) was subjected to random addition polymerization to obtain 58.8 kg of a reactant (comparative product 1). Further, 30 kg of Comparative Product 1 was placed in an airtight reaction vessel, and 1.9 kg (33 mol) of PO was subjected to block addition polymerization under the same reaction conditions to obtain 31.5 kg of base oil 1 used in the present invention. In addition, 2.43 kg of the crude reaction product was placed in an airtight reaction vessel, and a mixture of 46.0 kg of EO (1045 mol) and 11.5 kg of PO (198 mol) was subjected to random addition polymerization under similar conditions. 2) was obtained in an amount of 59.3 kg. Next, 15 kg of comparative product 2 was placed in an airtight reaction vessel, and 1.6 kg (27.6 mol) of PO was subjected to block addition polymerization under the same reaction conditions to obtain 16.1 kg of base oil 2 used in the present invention. In addition, put comparative product 2 in a 15 kg airtight reaction container,
3.0 kg (51.7 mol) of PO was subjected to block addition polymerization to obtain 17.4 kg of a reactant (comparative product 2'). Addition polymerization was carried out in the same manner as described above using the starting materials shown in Table 1 below, as well as AO and EO, to produce reaction products Base Oil 3 to Base Oil 6 and Comparative Products 3 to Comparative Products 8. Next, for each base oil and comparative product, after neutralizing the potassium hydroxide of the catalyst with an aqueous hydrochloric acid solution, the mixture was heated to 80°C to 120°C and dehydrated for 1 hour under reduced pressure of 30 mmHg or less to remove the precipitated salts. A purification operation was performed to prepare the sample for subsequent tests.

[Table] From Table 1, when comparing products with the same starting materials and corresponding numbers, it can be seen that the pour point tends to decrease in those produced by block addition polymerization of AO, and that the pour point tends to decrease in those produced by block addition polymerization of AO. However, it can be seen that the compounds of Comparative Product 2' and Comparative Product 6', which are outside the specific range of the present invention, have poor water solubility and become cloudy, so they are not suitable as components of water-based lubricating oil. Example 1 The following water-based lubricating oil composition containing the polyoxyalkylene glycol compound shown in Table 2 was prepared,
Tests were conducted for lubricity, foaming, oxidation stability and metal corrosion. Water-based lubricating oil composition Compounding ratio (wt%) Polyoxyalkylene glycol compound (base oil or comparative product) 15 Dipropylene glycol (water-soluble organic solvent) 45 Water 40 Total 100 (1) Lubricity test JISK-2519 (petroleum oil) Wear marks were measured using a four-ball tester based on the product load-bearing capacity test method. Test conditions were load 1.0Kg/cm ² and rotation speed.
The test was performed at 750 rpm for 30 minutes, and the test results are shown in Table 2.

【table】

[Table] From Table 2, when comparing the products of the present invention using each base oil with those using comparative products with corresponding numbers,
In both cases, the inventive product has a smaller wear scar diameter.
In particular, there is a large difference from those using comparative products 7 and 8, which are conventional products, so it can be seen that the product of the present invention has good lubricity. (2) Foaming property test A foaming property test was conducted based on JISK-2518 (Petroleum product foaming test method). However, the tests were conducted at 25℃ and 50℃, and the results are shown in Table 3. The numbers represent foam volume ((ml)).

【table】

[Table] From Table 3, it can be seen that the products of the present invention using each base oil have significantly lower foaming properties than those using comparative products, and are particularly excellent in defoaming properties after 10 minutes. (3) Oxidation stability and metal corrosion test Tests for oxidation stability and metal corrosion were conducted based on JISK-2234 (Test method for antifreeze). The conditions and test results are shown in Table 4. Test amount: 350ml Time: 2 weeks Temperature: 70±2℃ Air volume: 100±10ml per minute

[Table] In both cases, the greater the decline from the initial stage, the more deteriorated it is judged to be.
Table 4 shows that the products of the present invention using each base oil have better oxidation stability and metal corrosion resistance than those using comparative product 8. Example 2 The following water-based lubricating oil composition containing the polyoxyalkylene glycol compound shown in Table 5 was prepared,
Performance tests were conducted using this in a hydraulic pump. Water-based lubricating oil composition Blending ratio (wt%) Polyoxyalkylene glycol compound (base oil or comparative product) 14.5 Dipropylene glycol (water-soluble organic solvent) 38.5 Water 47.0 (Subtotal) 100.0 (Additionally the following to the above 100) Additive: Oleic acid 5 : Morpholine 0.2 : Potassium hydroxide 0.4 : Benzotriazole 0.2 : Ethylenediaminetetraacetic acid 0.1 : Antifoaming agent (Shin-Etsu Chemical Co., Ltd. KM-84) 0.01 Test Conditions: Hydraulic pump V-104-E type vane pump manufactured by Bitskers Oil amount 80 Setting pressure 70 Kg/cm ² Rotation speed 1200 RPM Pump inlet temperature 55°C Test time 100 hours The test results are shown in Table 5.

[Table] As is clear from Table 5, the water-based lubricating oil compositions of the present invention using each base oil had less pump wear and no sludge than those using comparative products. The appearance of the water-based lubricating oil composition after the test was also transparent, indicating that it is excellent as a hydraulic oil.

Claims (1)

[Scope of Claims] 1. 4 to 80% by weight of a polyoxyalkylene glycol compound of the following formula (1) or (2), and 20 to 96% by weight of water.
and a water-based lubricating oil composition whose main component is a liquid mixture consisting of 0 to 50% by weight of a water-soluble organic solvent. [R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 4 carbon atoms, X is an acidic atom or a nitrogen atom, and Y is a carbon atom
~4 alkylidene group, AO has 3 or 4 carbon atoms
oxyalkylene group, EO is oxyethylene group,
n is an integer of 1 or 2, and a and b are each from 10 to
500, c is 1 to 50, and the ratio of b/(a+c) is
The range is from 25/75 to 95/5, and the numbers in parentheses are those obtained by first randomly polymerizing a mole of AO and b moles of EO, and then block polymerizing c moles of AO at the end. ]