DE4328260A1 - Use of special polyethers as base oils for lubricant oil formations - Google Patents

Abstract

Lubricant oil formulations which are corrosive to a particularly small degree and are based on water-soluble polyethers are obtained if polyethers are used which were prepared by adding bases to mono- to tetrafunctional compounds containing active H atoms and addition of alkylene oxides, at least 40% by weight of the alkylene oxides being ethylene oxide, at 112 to 125 DEG C.

Description

The present invention relates to the use of in a special way Asked polyethers as a base oil for lubricating oil formulations with greatly reduced corrosivity.

EP-A-1 64 236 describes polyethers prepared from a long chain 1,2-epoxyalkane, tetrahydrofuran and a hydroxy compound and their Ver use as a lubricant. U.S. Patent 4,470,914 relates to addition products of alkylene oxides to bisphenol A, which were prepared at 135 ° C and their Use as a lubricant for filaments. Other lubricants, the polyethers included are z. B. in DE-OS 22 20 338 and BE-PS 660 991 described.

In none of these cases has it been recognized that the corrosivity of the lubricating oils of depends on the conditions of the Epoxidauflagerungs reaction.

It has now been found that such water-soluble polyethers as base oils for Lubricating oil formulations are particularly suitable, which were prepared by Substituting mono- to tetrafunctional, active H-containing verbin with strong bases and additions of alkylene oxides, wherein at least 40 wt .-% of the alkylene oxides are ethylene oxide, at 112 to 125 ° C. That after the Addition reaction mixture can be worked up as usual.

In the mono- to tetrafunctional, active H-containing compounds it may be, for example, monohydric to tetrahydric alcohols, for. B. order Butanol, hexanol, ethylene glycol, propylene glycol, diethylene glycol, glycerol, tri  methylolpropane, pentaerythritol, triethanolamine and their addition products with 1 to 4 alkylene oxide units.

It is also possible to use mixtures of different alcohols or mixtures of alcohol (s) with alcohol-alkylene oxide addition products, for example mixtures of Butanol and glycerol or propylene glycol and trimethylolpropane use.

As strong bases, for example, hydroxides, oxides, carbonates and Bicarbonates of alkali metals and tetraalkylammonium hydroxides in Question. Preference is given to potassium hydroxide, sodium carbonate, potassium carbonate, Sodium hydroxide and lithium hydroxide. The strong bases can be, for example in an amount of 0.05 to 5.0 wt .-%, based on the finished polyether, be used. Preferably, this amount is 0.07 to 0.5 wt .-%.

The temperature at which the strong bases are added is without particularity Meaning. For example, the addition can be carried out at 10 to 50 ° C, especially at room temperature. The reaction mixture should be after this Operation should be as anhydrous as possible, which is why you may have existing water generally removed by distillation.

The addition of alkylene oxides, for example, carried out so that Introduces ethylene oxide in the reaction mixture. One can also use ethylene oxide and other alkylene oxides, for example propylene oxide or C₄- to C₈-alkylene oxides attach, in which case the proportion of ethylene oxide at least 40 wt .-%, before preferably at least 50 wt .-%, based on the sum of the alkylene oxides is. For example, ethylene oxide and another alkylene oxide are added Use, so you can the ethylene oxide and the other alkylene oxide as a mixture, simultaneously but separately or in any order one after the other. It then arise polyether, the ethylene oxide units and units of the other Alkylene oxide in random distribution or in homogeneous blocks. Preferably, ethylene oxide is used alone or ethylene oxide and propylene oxide, wherein the ethylene oxide content is preferably between 40 and 65% by weight to the sum of ethylene oxide and propylene oxide. The attachment of Epoxides can be made in one or more reaction stages.  

It is also possible to use mixtures of ethylene oxide and mixtures of different composition be attached to other alkylene oxides in succession. It then creates poly ethers containing alkylene oxides in blocks having different compositions have.

Alkylene oxides can be used, for example, in an amount of 20 to 300 moles, based on a compound containing active H atoms in the compounds present active H atom, use. Preferably, this amount is between 26 and 286 moles.

It is an essential feature of the present invention that the Alkylene oxide addition carried out at 112 to 125 ° C. Preference is given to plant temperatures of 118 to 122 ° C. When you look at the deposition of epoxides Performs in several reaction steps, so you can proceed so that one initially attaching a portion of the alkylene oxide, z. B. 5 to 15 moles of alkylene oxide per active H atom, then possibly worked up as usual and finally the residual alkylene oxide attaches. The first reaction stage may optionally also be carried out at temperatures below 112 ° C, z. B. at 100 to 110 ° C.

After completion of the addition of alkylene oxides, it is generally advantageous the reaction mixture for a certain time, for. B. 0.5 to 5 hours on elevated Keep temperature so that all alkylene oxide abreacted.

Thereafter, the reaction mixture is worked up as usual, for example by Addition of an organic or inorganic acid for neutralization and by Distillation of water and other volatile components. That at the Optionally, distillation of precipitated salt may be removed by filtration.

If desired, the polyether thus prepared and isolated can be Add antioxidant, z. B. in an amount of 0.01 to 0.50 wt .-%. Suitable for example, di-tert-butyl-p-cresol, methoxyphenol and 2,6-di-tert. butyl-4-methylphenol.

Polyethers to be used according to the invention preferably have a right neric functionality from 1.0 to 4.0, d. H. they contain 1.0 to 4.0 on average  Polyether chains per molecule. The functionality essentially depends on how many active H atoms are one molecule of active H atoms used? containing compound. Is, for example, a dihydric alcohol, z. As propylene glycol, have been used, the polyether formed has a Functionality of approx. 2. By using mixtures of compounds with active H atoms whose constituents have a different number of active Contain H atoms per molecule, one can use polyether with non-integer Functionalities received. Also impurities in the used Compounds with active H atoms, eg. As small amounts of water, the Influence the functionality of the polyethers formed. Particularly preferred the polyethers to be used according to the invention have a functionality of from 1.0 to 3.0 on.

Furthermore, it is preferable to use those polyethers according to the invention which an OH number of 12 to 56, a viscosity of 60 to 1500 mm² / s (at 25 ° C, measured with an Ubbelohde viscometer) and a residual water content of less than 0.06% by weight.

Particularly preferred polyethers to be used according to the invention have the following combinations of OH numbers and viscosities measured as above:
38 to 42/73 to 81, 22 to 26/210 to 230, 16 to 18/430 to 470 and 13 to 15/1000 to 1100. The viscosities indicated in each case by the slash relate to measurements according to Ubbelohde at 40 ° C.

The invention to be used as base oils for lubricating oil formulations Water-soluble polyethers are characterized by having little if any corrosive. In any case, they are much less corrosive than water-soluble polyethers of other materials and / or in compliance other parameters, especially at other Alkylenoxid Anlagerungstempera tures were produced.

From the inventively used as base oils for lubricating oil formulations Polyethers can be prepared ready-to-use lubricating oil formulations for example, by addition of customary additives (eg sterically hindered Phenols and / or methoxyphenol as oxidation inhibitors, corrosion inhibitor  gates and / or wear protection agents such as higher fatty acids and / or their Salts) and / or by mixing with other base oils. With such others Base oils may be z. B. to other polyethers than the invention to using and / or, optionally ethoxylated and / or propoxylated, Natural fats and / or oils act. Examples of corrosion inhibitors are Tolutriazole, dimer fatty acid, phosphoric acid, polyphosphates, phosphonobutane tricar Bonsäure and Phosphormono- and Diisotridecylester.

Lubricating oil formulations containing the base oils to be used according to the invention th, are particularly suitable as transmission oils.

Examples A. Preparation of polyethers to be used according to the invention example 1

In a reaction vessel at room temperature with stirring 659.0 g Butyl diglycol and 53.3 g of KOH 45% aqueous submitted. The mixture was added 90 ° C and 16 mbar dehydrated for one hour. After heating to 120 ° C were below 0.4 to 0.6 bar, first 1815.9 g of ethylene oxide and 2974.9 g of propylene oxide as Mixture and then added slowly at 120 ° C 550.2 g of ethylene oxide. After completion of epoxide addition was stirred for a further 5 h at 120 ° C.

The alkaline polymer was prepared by adding dilute aqueous Neutralized sulfuric acid and dehydrated at 105 ° C and 1 mbar for 3 hours. Subsequently, precipitated potassium sulfate was separated by filtration. The The product obtained had the following parameters:

OH number (mg KOH / g) 40.1 Water content (wt.%) 0.01 medium functionality 1.0 (from starting alcohol) average molecular weight 1399 (calculated from starter alcohol and OH number) Viscosity at 40 ° C (mm² / s) 75

It thus complied with ISO VG 68

Comparative Example A

The procedure was as in Example 1, but the addition of the Alkylene oxides carried out at 100 to 110 ° C. The product obtained showed the following parameters:

Water content (wt.%) 0.01 Viscosity at 40 ° C (mm² / s) 77

Comparative Example B

The procedure was as in Example 1, but the addition of the Alkylene oxides carried out at 140 ° C. The product obtained had a Water content of 0.02 wt .-% and a viscosity at 40 ° C of 70 mm² / s.

Comparative Example C

The procedure was as in Example I, but the addition of the Alkylene oxides carried out at 155 ° C. The product obtained had a Water content of 0.02 wt .-% and a viscosity at 40 ° C of 76 mm² / s.

Example 2

In a reaction vessel at room temperature with stirring 324.2 g Butyl diglycol and 43.3 g of aqueous KOH 45% pure submitted. The mixture was added 90 ° C and 16 mbar dehydrated for one hour. After heating to 120 ° C were below 0.4 to 0.6 bar 3137 g of ethylene oxide and 3137 g of propylene oxide as a mixture gradually added. After completion of Epoxidzugabe for another 5 h at Stirred at 120 ° C.

The alkaline polymer was worked up as in Example 1. The obtained Product had the following parameters:

OH number (mg KOH / g) 20.6 Water content (wt.%) 0.02 medium functionality 1.0 (from starting alcohol) average molecular weight 2723 (calculated from starting alcohol and OH number) Viscosity at 40 ° C (mm² / s) 243

It thus complied with ISO VG 220  

Comparative Example D

The procedure was as in Example 2, but the addition of the alkylene was oxide carried out at 100 to 110 ° C. The product obtained had the following Parameters on:

Water content (wt.%) 0.05 Viscosity at 40 ° C (mm² / s) 240

Comparative Example E

The procedure was as in Example 2, but the addition of the alkylene was oxide carried out at 140 ° C. The product obtained had a water content of 0.03 wt .-% and a viscosity at 40 ° C of 235 mm² / s.

Example 3

In a reaction vessel at room temperature with stirring 186.5 g Butyl diglycol and 38.7 g of aqueous KOH 45% pure submitted. The mixture was added 90 ° C and 16 mbar dehydrated for one hour. After heating to 105 ° C were below 0.4 to 0.6 bar 265 g of ethylene oxide and 397 g of propylene oxide as a mixture and then at 120 ° C 2904 g of ethylene oxide and 3485 g of propylene oxide as a mixture gradually added. After completion of Epoxidzugabe for another 5 h at Stirred at 120 ° C.

The resulting alkaline polymer was worked up as described in Example 1 is working. The product obtained had the following parameters:

OH number (mg KOH / g) 19.6 Water content (wt.%) 0.01 medium functionality 1.0 (from starting alcohol) average molecular weight 2862 (calculated from starting alcohol and OH number) Viscosity at 40 ° C (mm² / s) 500

It corresponded to 150 VO 460

Comparative Example F

The procedure was as in Example 3, but the addition of the alkylene was oxides in both stages at 100 to 110 ° C made. The product obtained had the following parameters:

Water content (wt.%) 0.04 Viscosity at 40 ° C (mm² / s) 450

Comparative Example G

The procedure was as in Example 3, but the first stage was the Addition of alkylene oxides at 100 to 110 ° C and the second stage of Alkylenoxidanlagerung carried out at 140 ° C. The product obtained had a Water content of 0.03 wt .-% and a viscosity at 40 ° C of 480 mm² / s on.

Example 4

In a reaction vessel at room temperature with stirring 92.2 g Butyl diglycol and 20.0 g of aqueous KOH 45% pure submitted. The mixture was added 90 ° C and 16 mbar dehydrated for one hour. After heating up at 100 to 110 ° C below 0.4 to 0.6 bar 131.1 g of ethylene oxide and 196.3 g of propylene oxide as Mixture and then 3470.5 g of ethylene oxide and 4559.9 g of propylene oxide as Mixture at 120 ° C gradually added. After completion of epoxide addition was stirred for a further 5 h at 120 ° C.

The resulting alkaline polymer was worked up as described in Example 1 is working. The product obtained had the following parameters:

OH number (mg KOH / g) 17.4 Water content (wt.%) 0.01 medium functionality 1.0 (from starting alcohol) average molecular weight 3224 (calculated from starting alcohol and OH number) Viscosity at 40 ° C (mm² / s) 1110

It corresponded to ISO VG 1000

Comparative Example H

The procedure was as in Example 4, but both stages of the addition were of alkylene oxides at 100 to 110 ° C performed. The product obtained showed the following parameters:

OH number (mg KOH / g) 14 Water content (wt.%) below 0.5 Viscosity at 40 ° C (mPa · s) 1050

Comparative Example I

The procedure was as in Example 4, but the second stage was the Addition of alkylene oxides carried out at 140 ° C. The product obtained had a water content of 0.02 wt .-% and a viscosity at 40 ° C of 1100 mm² / s.

Example 5

In a reaction vessel at room temperature with stirring 94.4 g Glycerol and 76.7 g of KOH (45% aqueous solution) submitted. The mixture was dehydrated at 90 ° C and 16 mbar for one hour. After heating were added 100 to 110 ° C under 0.4 to 0.6 bar 89.13 g of propylene oxide added, then at 120 ° C, a mixture of 3454.3 g of propylene oxide and 2362.3 g of ethylene oxide gradually added. After completion of epoxide addition was another 5 Stirred at 120 ° C for hours.

The resulting alkaline polymer was described as in Example 1 worked up. The product obtained had the following parameters:

OH number (mg KOH / g) 31.0 Water content (% by weight) 0.02 Viscosity at 40 ° C (mm² / s) 465 medium functionality 3 (from the starting alcohol) average molecular weight 5429

Comparative Example J

The procedure was as in Example 5, but the second stage was the Addition of alkylene oxide carried out at 107 ° C. The product obtained showed the parameters on:

Water content (wt.%) 0.02 Viscosity at 40 ° C (mm² / s) 455

Comparative Example K

The procedure was as in Example 5, but became the second stage of the plant tion of alkylene oxides carried out at 140 ° C. The product obtained had the Parameters on:

Water content (wt.%) 0.01 Viscosity at 40 ° C (mm² / s) 480

B. Testing the corrosion protection properties

These tests were carried out in accordance with DIN 51 585 - method A (edition December 1971). Where:

Corrosion degree 0: no corrosion
Corrosion grade 1: low corrosion, no more than 6 corrosion spots, no more than 1 mm diameter
Corrosion grade 2: moderate corrosion, not more than 5% of the surface corroded
Corrosion grade 3: severe corrosion, over 5% of the surface corroded.

The results obtained are summarized in the following Table 1.

Claims (10)

1. Use of water-soluble polyethers as base oils for lubricating oil formulations, characterized in that the polyethers have been prepared from mono- to tetrafunctional active H-containing compounds by addition of strong bases and attaching alkylene oxides, wherein at least 40 wt .-% of Alkylene oxides are ethylene oxide, at 112 to 125 ° C. 2. Use according to claim 1, characterized in that it is at the polyethers are those which include ethylene oxide units and units of another alkylene oxide in random distribution. 3. Use according to claim 1, characterized in that it is at the polyethers are those which contain alkylene oxides in homogeneous or contain differently composed blocks. 4. Use according to claims 1 to 3, characterized in that in the preparation of the polyether, the addition of alkylene oxides in has carried out several stages. 5. Use according to claim 4, characterized in that between the Addition stages a workup is performed. 6. Use according to claims 4 and 5, characterized in that one a first addition stage at temperatures below 112 ° C and a second Addition stage at 112 to 125 ° C has performed. 7. Use according to claims 1 to 6, characterized in that one additionally uses a corrosion inhibitor. 8. Use according to claims 1 to 7, characterized in that after the addition, the reaction mixture has worked up by addition of acid for neutralization and by distillation of water and other volatile components.   9. Use according to claims 1 to 8, characterized in that the Polyether has a functionality of 1.0 to 4.0, an OH number of 12 to 56, a viscosity of 60 to 1500 mm² / s (at 25 ° C, measured in Ubbel Ohde viscometer) and a water content of less than 0.06 wt .-% respectively. 10. Use according to claims 1 to 9, characterized in that it is in the lubricating oil formulations is gear oils.