NO143707B - SMOEREMIDDELBLANDING. - Google Patents

Description

The invention relates to lubricants/mixtures and more

especially lubricant mixtures which are normally exposed to degradation

ning of ultraviolet light such as are present in sources of actimic radiation, such as sunlight. Even more particularly, the invention relates in one of its aspects to lubricant mixtures, e.g.

oils with lubricating viscosity, hydrocracked lubricating oils, hydraulic

motor oils, mineral oils or fractions thereof, oils for cars, gear oils, transmission fluids, waxes, greases and other forms of lubricants which normally require the presence of stabilizers against the degradation effects of ultraviolet light.

In general, the production of lubricant mixtures provides,

e.g. lubricating oils produced by hydrocracking, a relatively high viscosity index and allowing the use of certain raw materials that would be unsuitable for other processes. On the other hand, however,

time hydrocracked lubricating oils tend to poor stability over

for ultraviolet light degradation, by the rapid formation of suspension,

dert and/or precipitated insoluble material upon exposure to ultraviolet light, e.g. sunlight, or other sources of actinic radiation

Eng. Compounds capable of absorbing ultraviolet light, e.g. hydroxybenzophenones, and hydroxyphenylbenzotriazoles, have offered some improvement in the light stability of hydrocracked oils. Conventional antioxidants have also provided these benefits.

In the literature, Heskins and Guillet proposed in "Mechanism

of Ultraviolet Stabilization of Polymers", Macromolecules 1, 97

(1968) first the energy transfer mechanism by ultraviolet protection. Commercially available ultraviolet stabilizers are also listed by class and function and identified with respect to structure in the Kirk-Othmer Encyclopedia in "Encyclopedia of Chemical Technology"; 2nd edition, volume 21, pages 115-122. Uri indicates i

"Thermal and Photochemical Oxidation of Polymers and Its Prevention",

Chemistry and Industry, March 1, 1976, pages 199-203, conventional antioxidant effects (hydroperoxide cleavage and free-radical scavenging) of bis(stilbenedithiolato)nickel and its ultraviolet inhibitory properties. In British patent document 1,263,910 bis(stilbenedithiolato)nickel is described as an antioxidant for plastic materials. The patent document also indicates superior hydroperoxide splitting ability of this additive. US Patent 3,832,304 describes the use of aromatic azo compounds for the stabilization of hydrocracked oils. None of the aforementioned publications show lubricant mixtures containing the organosulfur-containing nickel complexes described here.

In accordance with the invention, it has been found that stabilization against ultraviolet light, which is present in sunlight or other sources of actinic radiation, can be effectively imparted to lubricant mixtures by incorporating organosulfur-containing nickel complexes into them. These nickel complexes are particularly effective against ultraviolet heat degradation in such lubricating media as oils of lubricating viscosity, hydrocracked lubricating oils, hydraulic oils, mineral oils or fractions thereof, motor oil, gear oils, transmission fluids, waxes, lubricating greases and other forms of lubricant mixtures which normally requires the presence of stabilizers against the degradation effect in ultraviolet light\

The organosulfur-containing nickel complexes can be used effectively, in any amount sufficient to

give the lubricant the desired degree of protection against ultraviolet degradation. According to the invention, the nickel complex is used in an amount of from 0.01 to 5%, by weight, and preferably in an amount of from 0.1 to 2% by weight, calculated on the total weight of the lubricant mixture. The term "nickel complex" is used herein to include nickel compounds having a chelate ring formation. As indicated above, the organosulfur-containing nickel complexes can be incorporated into any lubricant media which may include oils of lubricating viscosity and also greases in which any of the aforementioned oils are used as a carrier. In general, synthetic oils can also be effectively protected against ultraviolet degradation or can also be used in combination with mineral oils or as lubricating grease carriers. Typical synthetic carriers include polyisobutylene, polybutenes, hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, trimethylolpropane esters, neopentyl and pentaerythritol esters, di(2-ethylhexyl)sebacate,

di (2-ethylhexyl) adipate, dibutyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorous acids, liquid urea compounds, ferrocene derivatives, hydrogenated mineral oils, chain type polyphenols, siloxanes and silicones (polysiloxanes), alkyl substituted diphenyl ethers, e.g. . a butyl-substituted bis (p-phenoxyphenyl) ether, phenoxyphenyl ether, etc.

The sulphur-containing nickel complexes used in accordance with the invention are commercially available and are sulphur-containing nickel phenol phenolates such as e.g. is described in U.S. patents 2 971 940 and 2 971 941. They comprise nickel salts of bisphenol sulphides in which only part of the total phenolic hydrogen has been replaced by nickel. They have structural formulas as follows:

where R is H or an alkyl group, preferably with up to 30 carbon atoms.

A mixture of these two compounds (referred to here as "mixture A"), where R is octyl, is a good ultraviolet stabilizer.

Sulfur-containing nickelamine complexes are described in US Patents 3,215,717 and 3,313,770.

Representative of the nickel alkylamines are [2,2'-thio-bis(4-tert-octylphenolato)]-n-butylamine nickel with the structure

Representative of the nickel thiophosphates are nickel di(4-methyl-2-pentyl)dithiophosphate with the structure

Representative of the nickel dithiocarbamates are nickel dibutyl dithiocarbamate with the structure

In order to assess the effectiveness of the organosulfur-containing nickel complexes according to the invention against ultraviolet degradation in lubricating media, the following test was used: This test used a base oil, namely a hydrogen-terminated hydrocracked 100" oil obtained by dewaxing at 385°C bottoms fraction from a first stage product in a fuel hydrocracker. Blends of additives with the aforementioned hydrocracked base oil were tested by exposing 20 grams of the test oil in a stoppered 112 gram tall bottle to daylight on a windowsill with southeast exposure. The test oil was observed every day with respect to suspended insoluble products, which usually progress from a mist to a suspended plume and fall out, which is generally preceded by mist formations or plumes and often consists of mist or plumes that have settled. in the following Table I it is indicated results obtained using 0.1% by weight of additives in the aforementioned hydrocracked base oil. From the table it will be seen that the nickel complexes according to the invention are much more effective against ultraviolet degradation (examples 2-6) than the best of the commercially available conventional anti-oxidation agents and ultraviolet absorbers (examples 7-11). In the following table II, the results obtained using 0.5% by weight of additives are given for the above-described hydrocracked base oil from table I. It will also be seen from the table here that the organosulfur-containing nickel complexes in the lubricant mixtures. according to the invention, when subjected to the test described above, are much more markedly effective against ultraviolet degradation (Examples 2-4) than the best of the aforementioned commercially available conventional antioxidants and ultraviolet absorbers (Examples 5-9) .

The following table shows the effectiveness of a typical representative nickel complex according to the invention versus nickel bis(octylphenol)sulfide in a hydrocracked base oil designated 200" (base oil 1) and also in another base oil (base oil 2) versus a heavy vacuum gas oil. As. shown in the table, the nickel (octylphenol) sulphide according to the invention was markedly effective in reducing the ultraviolet degradation of the respective base oils.

The following Table IV shows the effectiveness of typically representative nickel complexes according to the invention as antioxidants in lubricant mixtures. The representative additives were mixed individually in solvent-refined paraffinic mineral oil termed. 150" and was subjected to a standard test, called the "Rotary Bomb Oxidation Test", in accordance with test method ASTM D-22 72.

As will be seen from the table, the oxidation life of the base oil was markedly increased by the antioxidant effect provided by the nickel complexes according to the invention.

Although the invention is described by reference

to preferred mixtures and components for such, it will be understood by the expert in the field that deviations from the preferred embodiments can be made in an efficient manner and are within the scope of the invention.

Claims (2)

1. Lubricant mixture which is stabilized against degradation by ultraviolet light, characterized in that it contains as a stabilizer a mixture of from 0.01 to 5% by weight of nickel-thiobis (phenol-phenolates) with the following formulas: where R is hydrogen or an alkyl group, suitably with up to 30 carbon atoms, R being preferably octyl. 2. Lubricant mixture as claimed in claim 1, characterized in that the nickel complex is present in an amount from 0.1 to 2% by weight.