DE2744978C2 - Process for the production of a grease and the grease obtainable therewith - Google Patents

Description

The invention relates to a method for producing a Grease and those available through this process Greases.

Numerous greases of various types are known the constituents due to the soaps and / or because of the high soap content are relatively expensive.

The invention has set itself the task of one less propose expensive grease, which is not necessarily so has all the properties of known specialty lubricants, but in numerous properties as an all-purpose lubricant can be used. Furthermore, the invention given the task of a process for producing a to propose such lubricants or novel ones To propose greases based on calcium complexes.

To solve this problem, a method of manufacture a grease according to the main claim and a grease proposed according to claim 8.

Preferred embodiments of the method for producing the grease result from the subclaims.  

The greases according to the invention have dropping points of at least 170 ° C and preferably 200 ° C, for example above 250 or even over 300 ° C. In addition, the greases of the invention meet in addition to such dropping point values, the requirements at 140 ° C in test B of the SKF R2f test. At this test, a test bed is operated to determine whether dry running takes place. Although in practice complex calcium fats used at high temperatures they tend to slide lubrication running dry or the bearing becoming dry due to a more or less complete separation of the Grease from the sliding surfaces in the bearing.

The SKF bearing lubrication test device according to DIN Regulation 51 806 is a recognized test device for Observation of dry running. Trial B is at 1500 rpm and carried out with additional heating.

With the invention, such a calcium complex grease with a dropping point of at least 300 ° C is preferably proposed that in this test B at temperatures of at least 140 ° C still behaves well.  

Preferred is the lower carboxylic acid of the complex soap Acetic acid is used, although also formic acid or Propionic acid can be used. Preferably, the complex carbohydrate a mixture of higher soap Tallow fatty acids, either as such or in their Glyceride form can be used as sebum. It can other acids can also be used, for example Stearic acid or hydrogenated fish oleic acids, which are essential Mixtures of saturated C₁₄ to C₂₂ carboxylic acids are the practically commercially available stearic acid with regard saturation and average molecular weight correspond.

It is useful if the weight ratio of fatty acids to the lower carboxylic acids greater than 1: 1 and preferably is in the range of 1.5: 1 to 2.0: 1, with one mole ratio from 3: 1 acetic acid to fatty acid is particularly preferred becomes.

Usually 0.5 to 2.5% by weight is one in the grease Oxidation inhibitor present, which is conveniently a phenyl-α- is naphthylamine or a polymerized trimethyldihydroquinol compound. If necessary, up to to 5 wt .-% corrosion inhibitors the invention Grease are added, usually in a range of  0.25 to 2.5 and preferably 0.5 to 1.0% by weight, inclusive known sulfonates of calcium or barium. A commercial one such product is under the name Alox® 2116A known.

If necessary, one or more additives can also be present such as agents for improving the high pressure properties such as dibenzyl disulfide or sulfurized Sperm oil. Furthermore metal deactivators such as complexing Ethylenediamine compounds; prevention means wear like zinc dialkyldithiophosphate, as well as water resistant Additives such as high molecular weight isobutylene polymers. Usually up to 2.5% by weight, based on the total grease, of these connections, mostly in one Amount from 0.25 to 1% by weight.

Accordingly, the grease of the present invention is usually made from more than 80% by weight of the base oil; it does not contain any substantial amounts of water, usually less than 0.1 wt .-%.

The paraffinic mineral base oil preferably has a viscosity in a range of 105 to 115 mm² / s at 40 ° C, one Minimum flash point of at least 245 ° C and a maximum Pour point of -5 ° C, preferably -10 ° C or lower. It is  a particular advantage that in the oil according to the invention can use paraffinic base oils.

Naphthenic mineral base oils are preferably phenolic or other extracted hydrofinished oils. Preferably the oil has a viscosity in a range from 105 to 115 cSt mm² / s at 40 ° C, a minimum flash point of at least 225 ° C and a maximum pour point of -5 ° C and preferably -10 ° C or lower.

The mineral base oil can be at least partly by a or several other oils, for example by synthetic Oils are replaced provided they are made under the manufacturing conditions are stable. If not stable though are miscible with mineral oils, such as ester or Diester oil bases, the fat may be initially proportionate Mineral oil are produced and then with the synthetic Oil or with another base oil to the total base oil content of the corresponding fat can be diluted. Examples synthetic oils are polyethylene glycol ether and polypropylene glycol ether.

A particularly preferred grease according to the invention conducts about 3% by weight of glacial acetic acid, about 5% by weight of tallow fatty acids and about 3% by weight of slaked lime. The base oil is preferred a paraffinic oil.  

In the production process according to the invention, the acids are heated and the calcium base with at least part of the base oil so the maximum temperature that the mixture reached during the heating in one area is from 240 to 250 ° C, whereupon the oxidation inhibitors and optionally Remaining base oil residue be added.

Slaked lime is the preferred saponifying calcium base; however, calcium oxide can also be used. The base is preferably used in amounts of 20 to 40, in particular 25 up to 35% by weight, based on the total content of acids and Calcium base used. It is particularly useful if the amount of calcium base used is such that the final grease an alkalinity according to AM-S 160.40 from 0.3 to 1.5% by weight and preferably 0.3 to 0.6% by weight.

The preferred range for the maximum temperature is 242 to 248 ° C and especially 243 to 247 ° C. It will be best Maintain maximum temperature for at least 30 minutes.

If necessary, the production can be carried out under an inert gas such as for example nitrogen or carbon dioxide; this  is useful if the flash point of the mineral base oil or of the other base oils close to the maximum temperature at the Manufacturing lies. If the mass during manufacture foams, small amounts of an alkali sulfonate, in particular Petroleum sulfonate used as an anti-foaming agent become. In all cases, antioxidants and Corrosion inhibitors or other common grease additives while cooling the mixture from the maximum manufacturing temperature added.

Surprisingly and unexpectedly, it was found that the raw and processed penetration (ASTM D217) the fat products have a minimum value and are almost constant, if the maximum manufacturing temperature in a range from 242 to 248 and in particular 243 to 247. This Phenomenon and other properties are explained below. It was also found that the inclination in particular higher temperature, is extremely low and in the field of greases based on lithium hydroxystearate lies.

In summary, according to the invention, a grease becomes suggested which is extremely inexpensive and lightweight available raw materials and that numerous properties of high-quality and expensive greases  based on lithium hydroxystearate shows and a is an excellent multi-purpose grease.

Example 1

A complex calcium grease was used of 5% by weight tallow fatty acids, 3% by weight glacial acetic acid, 3% by weight quenched Lime, 0.5% by weight phenyl-α-naphthylamine, while the rest is a paraffinic mineral oil with the above specified properties was. About half of the required Mineral oil amount was submitted and so long to about Heated 100 ° C until the tallow fatty acids, the slaked lime and glacial acetic acid were added.

Then up to 10% more mineral oil was added, followed by the mixture is further heated to 243 to 247 ° C and at this temperature was left for at least 30 minutes. The Alkalinity was approximately 0.6% according to AM-S 160.40. At the beginning The amine compound and remaining mineral oil were cooled added, after which the grease was homogenized.

The product was a grade 2 grease containing 10 to 12% by weight Self-content. The fat had a dropping point of about 300 ° C and passed the SKF 2RF test B at 140 ° C. The oil separation according to ASTM D 1742 was about 2.3 wt% while it  after 168 hours storage at 40 ° C according to IP 121 / DIN 51 817 Was 3.0% by weight. This grease corresponded to the EMCOR Corrosion test according to DIN 51 802.

By slightly increasing or decreasing the amount of Soap-forming ingredients can be mixed with a fat receive slightly higher or lower soap content. In however, all cases are intended to achieve an inventive Product and to achieve the maximum benefits Manufacturing temperature in a range from 240 to 250 ° C and in particular be maintained from 243 to 247 ° C.

Example 2

The procedure was analogous to Example 1, but now the maximum temperature changed in the range of 239 to 251 ° C has been; several types of grease were produced and according to ASTM D 217 on penetration in machined and unprocessed condition examined. From the graphic representation the following values were compiled, the show that the maximum manufacturing temperature (MMT) is very clearly influenced the penetration values and in one area from 243 to 247 ° C gives a surprising consistency.

The greases with the least penetration, that is the hardest greases are because of the extremely low Soap content of about 10 to 12 wt .-% and because of their manufacture from inexpensive raw materials those that come in one Maximum temperature range from 240 to 250 ° C, especially 243 up to 247 ° C.

The difference in penetration values of 45 points between the ASTM-D 217 values in processed and unprocessed condition, within the preferred range of the maximum Manufacturing temperature from 243 to 247 ° C is practical is the biggest difference possible. It is for example  possible by small changes in the amounts of Component this difference to less than 20 points reduce.

Claims (8)

1. A method for producing a grease based on a base oil from a paraffinic and / or naphthenic mineral oil and / or a synthetic oil and a complex calcium soap, in which the thickening component consists of a complex calcium soap, which is from a calcium base, a C₁ to C₃-aliphatic carboxylic acid and one or more fatty acids derived from the group of tallow fatty acids or their glycerides, stearic acids or hydrogenated fish oil acids, characterized in that

• a) the calcium base and the fatty acid (s) and the C _1-3 carboxylic acid in a weight ratio greater than 1: 1 are heated with at least part of the base oil, so that the maximum temperature of the mixture during the heating is in a range from 240 to 250 ° C. lies and then
• b) up to 5% by weight of one or more customary oxidation inhibitors and, if present, the rest of the base oil are added, the lubricating grease obtained containing 7 to 17% by weight of complex calcium soap.

2. The method according to claim 1, characterized in that one the fatty acids or glycerides and the C₁ to C₂ carboxylic acid used in a weight ratio of 1.5: 1 to 2.0: 1. 3. The method according to claim 1 or 2, characterized in that as tallow fatty acid and as C₁ to C₃ carboxylic acid Acetic acid used. 4. The method according to any one of claims 1 to 3, characterized in that the calcium base in an excess  Amount used to give the fat an alkali measure of 0.3 to 1.5 and preferably 0.3 to 0.6% by weight. 5. The method according to any one of claims 1 to 4, characterized in that one uses slaked lime as calcium base. 6. The method according to any one of claims 1 to 5, characterized in that at a maximum temperature in the range of 243 to 274 ° C works. 7. The method according to any one of claims 1 to 6, characterized in that the grease obtained 7 to 13 and preferably Contains 8 to 12 wt .-% of the complex calcium soap. 8. Grease obtainable by the process according to one of the Claims 1 to 7, characterized by a dropping point of at least 170 ° C and a dry running temperature, measured according to test B of the DIN Norm 51806, of at least 140 ° C.