DE939523C - Ester-based lubricants - Google Patents

Description

The invention relates to lubricants consisting of oily liquid esters, which in Dispersion a synergetic combination of oxidation and corrosion inhibitors contain.

Lubricants made from organic oily liquids tend to get exposed to air, especially at higher levels Temperatures, such as those occurring in engines and other work machines, lead to oxidation, whereby their stability through contact with metal surfaces, which give off metal particles, is even more essential is decreased.

There are numerous oxidation and corrosion inhibitors as well as combinations of such substances for Use in lubricating mixtures has been recommended. However, it is impossible to predict what classes of inhibitors can effectively support each other. In addition, the results obtained with a specific chemical group of lubricating oils do not indicate any ao Conclusion on the results to be expected in other groups.

The present invention relates to the composition of lubricants from oily liquids of the ester type, which can also be used as hydraulic fluids and are resistant show against degradation or oxidation as well as improved corrosion properties.

It has been found that such valuable lubricants can be obtained by oily liquids of the ester type adding small amounts of an epoxy compound and an arylamine,

Epoxy compounds are compounds which have at least one group

- C - C -

contain; d. H. a group in which two aliphatic carbon atoms are bonded through a single bond linked and also bound to the same oxygen atom by simple ether bonds are.

CH ₂ -CH-CH ₀

- O

CH,

Examples of organic substances containing the epoxy group are epoxypropane, 1,4-bis- (2,3-epoxypropoxy) -benzene, 1, 3-bis (3, 4-epoxybutoxy) benzene, glycidyl stearate, glycidyl caproate, 2, 3 - epoxypropoxycyclohexane, Glycidyl phenyl ether.

A preferred group of epoxy compounds are polymers, ■ which by reaction of a polyhydric alcohol or phenol with a sufficient excess of a polyepoxide or one halogen-containing epoxy, preferably in the presence of an alkaline catalyst, are obtained. A particularly suitable reaction product is the product from the reaction between 2,2-dip-phenolpropane and epichlorohydrin, which has the structure

0-CH ₂ -CH-CH ₂

OH

0-CH ₉ -CH-CH,

having. In this formula, η means a number from about 0 to about 10.

Another group of suitable epoxy compounds is made by polymerizing compounds with an epoxy group and a multiple carbon-carbon bond obtained in the presence of heat, oxygen, peroxy compounds, active light and the like, with no influence from the epoxy group will. These monomers can also be used with unsaturated compounds which do not contain an epoxy group contain, are copolymerized, e.g. B. with styrene, vinyl acetate, acrylonitrile and the like. Examples Such polymers and copolymers containing the epoxy group are poly (allyl-2, 3-epoxypropyl ether), Poly (2, 3 - epoxypropyl crotonate), allyl-2, 3-epoxypropyl ether-styrene copolymer, Methallyl - 3, 4 - epoxybutyl ether - allyl benzoate - copolymer.

Other suitable epoxy compounds are those substances which contain a plurality of epoxy-substituted organic radicals, preferably hydrocarbon radicals, which are bonded to other organic radicals, preferably likewise hydrocarbon radicals, by ether bonds. Examples are 2,2-bis (p-2,3-epoxypropoxyphenyl) -propane, 4,4'-bis- (2,3-epoxypropoxy) -diphenyl ether, 1,3-bis- (3,4-epoxypentoxy ) -benzene, i, 8-bis- (2,3-epoxypropoxy) -octane, 1,3-bis- (2,3-epoxybutoxy) -cyclopentane, 4,4'-bis- (2-oxy-3, 4-epoxybutoxy) diphenyldimethyl methane. The most suitable organic substances containing an epoxy group are those which evaporate only to a small extent from the stabilized mixtures, e.g. B. So those with a boiling point above 300 ⁰ . If polymeric epoxides are used, an average molecular weight between about 300 and about 1500 is expediently chosen. i ° 5

The arylamine preferably contains a plurality of amino-aryl bonds, and the most important Groups of aryl compounds for use in the mixtures according to the invention are the diaminodiarylalkanes, Thiodiarylamines, diarylamines and alkylated phenylenediamines.

The most effective compounds are the N, N'-tetraalkyldiaminodiphenylalkanes, d. H. Diaminodiphenylalkanes, in which the two hydrogen atoms of each amino group are substituted by alkyl groups, each of which preferably has 1 to 4 carbon atoms. The N, N'-TetraalkyldiaminodiphenykQethane, for example N, N'-tetramethyldiaminodiphenyhnethane, which the formula

H ₃ C

CH,

has, and N, N'-tetramethyldiamino-i, i-diphenylethane with the structure

H ₃ C. .CH ₃

H _a C-

CH,

and 2, 2'-diethyl-4, 4'-diaminodiphenylrhethane with ίο the structure

C ₂ H ₅

C ₂ H ₅

H, N

NH,

The thiodiarylamines have the general formula R "

N
R / N R '

In this, R and R 'are aromatic radicals, and R "denotes a hydrogen atom or an alkyl radical, preferably with 1 to 10 carbon atoms. Three particularly suitable subgroups are phenothiazine, thiophenyhiaphthylamine and thiodinaphthylamine and their substitution products. The substitution products can be substituents such as alkyl radicals (preferably each having less than six carbon atoms), hydroxyl groups or amine radicals, the latter can be modified in a similar manner by replacing hydrogen atoms with other groups. Examples of compounds of this type are: i, 9 -dimethylphenothiazine, 3, 7-didecylphenothiazine, 3,7- dioxyphenothiazine, 2, 8 -dibutylphenothiazine, 10 - ethylphenothiazine, 6, 2 '- thio 4-methylphenyl-jS-naphthylamine, 6, 2'-thiophenyl-6 - ethyl - β - naphthylamine, 6,2'- Thio-4-oxyphenyl / 3-napthylamine.

The aminothiodiphenylamines, which have the general formula, are particularly effective

N - _r

exhibit. In this formula, R and R 'are hydrogen atoms or alkyl, cycloalkyl, aryl or heterocyclic groups.

The aryl groups in the diarylamines can be the same or different, and there are in particular Phenyl and naphthyl radicals and their alkyl or alkylene substitution products. The following connections are typical examples: phenyl-a-naphthylamine, phenyl - /? - naphthylamine, diphenylamine, dia-naphthylamine, Di-ß-naphthylamine.

The additives are used in small amounts, which are sufficient to prevent corrosion and To improve the oxidation properties of the oily liquid ester, the effective amount being mixed with the changes in the particular conditions under which the mixture is used. In general are about 0.25 to 5%, calculated on the weight of the total mixture, of each additional component is sufficient.

These two types of additives work in oily ester-type liquids, the higher ones Temperatures in the presence of oxygen are exposed in a mutually increasing manner together. The synergetic effect is particularly noticeable when metals such as copper, iron, magnesium, Aluminum and cadmium are present. Esters, especially polyesters, speak in general on the synergetic combination of additives. But it has been found that this effect is particularly pronounced when the combination in an ester of an acid of phosphorus, an ester the silica or an ester of an organic carboxylic acid is used.

Esters of acids of phosphorus

As oil-like liquids based on phosphoric acid, the aliphatic esters of phosphoric acid are particularly suitable, but other compounds can also be used, for example phosphonates, ' Phosphinates or diphosphorus compounds of the general formula:

X X

I I.

ο = p - γ - ρ = 0

Here, X denotes a radical R or a radical OR. Y denotes a radical O R O, O R, R O or R. R represents represents an aliphatic hydrocarbon radical. The hydrocarbons substituted by phosphine oxide groups are not esters in the strict sense, but they are the rest of the formula given Compounds shown analog and can be used in the same way as oily liquids in the Find lubricants according to the invention use.

A preferred group of diphosphorus compounds are the bis (dialkylphosphonic) alkanes, in particular those with a branched structure.

Silica esters

Silicic acid esters are also highly responsive to the incorporation of the combined additives of the present invention. The silicic acid esters include alkyl, aryl, aralkyl and alkylaryl esters iao of silicic acid.

Esters of carboxylic acids

Another type of esters used with preference comprises those of the organic carboxylic acids, in particular

especially the complete esters of aliphatic dicarboxylic acids. Triesters such as trioctyl aconitate and hexatriol ester caproate can also be used. You can also use esters of monobasic and polybasic acids with polyhydric alcohols, e.g. B. Esters of fatty acids with alkylene glycols and esters of pentaerythritol.

In addition to the types of esters described above, a particularly suitable group

ίο of compounds made by esterification of silicic acid, acids of phosphorus or dicarboxylic acids with sulphurous alcohols; · 'the can be either thia alcohols or thio alcohols. The esters so produced show excellent results High pressure properties and a pronounced effect when using the combined additives within the meaning of the present. Invention.

To supplement the essential combination of inhibitors, the mixtures can also contain subordinate 65 Amounts of other additives such as viscosity improvers, extreme pressure additives, pour point depressants and or contain anti-wear agents.

The following examples illustrate the synergetic effect achieved through the use of the combination 70 of additives according to the present invention. The test method used to test the mixtures consisted of exposing 20 ecm of the mixture to ^{a temperature of 175 ° for 71 hours in the presence of 2.58 cm 2 of} different metals, while 1 liter of air was passed through the samples per hour. At the end of the test, the corrosion caused on the various metals, the percentage increase in the viscosity of the sample and the 80 acid number were measured.

Ver
search-
num-
mer Kind of liquid
Esters Weight o / o
of the ester
in the
mixture Epoxy
additive
Weight o / o * Phenyl-a-
naphthyl
aminine% Cu Weight
Mg _r loss
Fe mg / cm ²
CD Al o / oViskos.-
increase
at 37.7 ° acid
number I. Trioctyl phosphate 98 I. I. O, 52 + O, 16 79.4 O + 0.0 / O 8.5 3, O4 _ 98 O 2 l6.6 0.12 0.08 1.36 O, o8 17.0 14.4 - - 98 2 O 84.8 0.48 0.68 + 0.20 23.2 O 327.0 147.0 2 Triisooctyl 0 phosphate 100 44.7 70.6 58, i 0, l6 ■ 0.32 99.5 _ - 98 ■ 2 O 45.8 . 4.36 + 1.28 5.12 0.92 161.0 131.0 - - 98 O 2 5.32 24.28 0.0; 20.2z O, o8 81.0 19.8 _ . - 98 . I. I. 1.88 O 0.08 O O O 10.5 20.3 3 Bis- (2-ethyl- 0.20 hexyl) sebacate
Tricresyl phosphate 9 ¹
5 2 2 0.12 O 0.52 O O, O8 0.04 3, o o, 53 - Bis- (2-ethyl- hexyl) sebacate
Tricresyl phosphate 93
5 O 2 0 O 0.3 O O O 8.0 1.43 - Bis- (2-ethyl- hexyl) sebacate ■
Tricresyl phosphate 92.7 '
5 2.3 O 2.28 20.5 0.12 30.7 0.12 fixed 16.3 4th Tetra- (2-ethyl- hexyl) silicate 98 I. I. 0.48 0.1 . 0.56 0.60 0.32 3.0 0.16 - ■ - 98 O 2 0.08 O 1.28 0.04 4.5 0.15 -. - 98 2 O 1.16 0.12 25.5 O 210.0 16.0 5 Tetra- (7-methyl- thiaoctyl) - siEcat ,; 98 ■ 2 O 59.4 0.20 0, l6 O ¹ 100.0 6.38 - - ■ 96 2 2 3.68 0, l6 1.84 0.08 59.0 1.64 - .- 98 O 2 6.68 0.08 0.52 0.16 21.0 i, 34 6th Tri- (isooctyl) -. phosphate
Tricresyl phosphate 92
■ 5 3 O 4.8 0.2 25.0 0.1 313.0 i37, o - Tri- (isooctyl) - phosphate
Tricresyl phosphate 92
5 0 3 6.8 0.1 34.1 O - 33.0 - [ri- (isooctyl) - phosphate
Tricresyl phosphate 95
2 I. 2 0.1 O 0 O 7.5 8.6

*) The one used in these experiments
hydrin with a molecular weight of about

Epoxide was the reaction product of bisphenol and epichloro-125 300.

Further examples of compositions according to the invention are:

Weight percent

7 trioctyl phosphate 97.0

Di- (N, N'-sec-butyl) -p-phenylene-

diamine 2.0

Poly (allyl-2, 3-epoxypropyl ether),

Molecular weight 400 1.0

8 ethylene glycol diesters of the Capron

acid 97.0

Phenothiazine 1.5

Poly (2,3-epoxypropyl crotonate,

Molecular weight 350 1.5

9 diphenyl cresyl phosphate 98.0

N, N'-tetramethyldiamino-

diphenynethane 1.0

Glycidyl phenyl ether 1.0

Phosphoric acid diphenyloctyl ester .. 96.5

Bis (z, 3-epoxypropyl) ether 3.0

Dibenzylamine 0.5

Claims (1)

Claim: Ester-based lubricants, especially those based on phosphoric acid, silicic acid, mono- and dicarboxylic acid esters !!, characterized by a low content, preferably 0.25 to 5 percent by weight each, an epoxy compound, e.g. glycidyl phenyl ether, 2, 2 - bis - (p - 2, 3 - epoxypropoxyphenyl) propane or a condensation product of 2, 2-di-p-phenolpropah and epichlorohydrin, and an arylamine, e.g. B. Phenyl-a-naphthylamine, Phenothiazine or N, N'-tetramethyldiaminodiphenyhnethane. References: French Patent No. 974374; British Patent No. 681 091. 509 650 2.56