DD282470A5 - LUBRICANT FORMULATION WITH IMPROVED TRIBOLOGICAL PROPERTIES IN THE MIXING AREA - Google Patents

Abstract

The invention relates to a lubricating oil formulation with improved tribological properties in mixed friction region, which is suitable for use in particular for the production of motor oils, gear oils and industrial oils. The effect of friction and wear reduction is achieved by the addition of Alkylaminomethylenphosphonsaeureestern which are added as Friction Modifier a Grundoel or to a fully formulated OEl. {Lubricating oil formulation; tribological properties; Friction modifier; Mixed friction; Friction reduction; Verschleiszsenkung; phosphonic; Motor oil; Getriebeoel; Industrieoel}

Description

It is known that various phosphorus compounds, in particular phosphorus compounds, are also suitable as friction modifiers in lubricating oil formulations (for example OE 2 200661). Various phosphoric acid esters have been disclosed as friction mincers in DE 2912866, US 4228020, US 3702324, GB 2017748. The disadvantage of the compounds described lies in the costly production and in the inadequate improvement in the wear protection behavior, phosphonic acid esters which likewise contain nitrogen in the molecule (such as, for example, the tetraoctyl (dimethylamino) methylene diphosphonate corresponding to US 3696036) have zi tar AW- Properties, but a friction-reducing effect in the sense of the Friction Modifier has not become known. Finally, α-phosphonolaurylmides are described as friction and wear-reducing constituents of lubricating oil formulations (compare US Pat. No. 4,525,289). However, their positive effect is bound to a specific composition of the additive package and thus disadvantageous in the preparation of Schmierr'formulierungen with partially predetermined ingredients.

Target of "/tindu.g

The aim of the invention is to provide a Schmierölformuliorung with improved tribological properties, which leads, especially under mild mixed friction conditions to reduce energy consumption and extend the life of lubricated friction pairings. The friction modifiers to be used for the preparation of the lubricating oil formulation should be easy to prepare and be soluble in the base oil. Their addition to the additive package must not show any undesirable side effects in the lubricating oil formulation that forces them to make major changes in their composition.

Explanation of the essence of the invention

The object of the invention is to develop a lubricating oil formulation which already has a friction and wear-reducing effect in lubricated friction pairings in the field of mild mixed friction.

Erfindungsgnmäß the object is achieved in that to be known per se lubricating oil formulations consisting of one or more Griir.dölen with or without additive package, additionally an alkylamino-bis-methylenephosphonic the general formula 1 or a Dialkylaminomethylenphosphonsäureester the general forms! 2 is added in a concentration between 0.01% by mass to 10% by mass as a friction modifier.

$ _M

Here, R ^{1 is} an alkyl radical having straight or branched aliphatic chains having 8-20 C atoms, R ^{2 is} an aliphatic Aikylrest having 1-10 C atoms. Furthermore, R ^{3 is} an alkyl radical having straight or branched aliphatic chains having 8-20 C atoms, R ^{4 is} an alkyl radical having straight or branched aliphatic chains having 1-20 C atoms and R ^{5 is} an aliphatic alkyl radical having 1-10 C atoms represents.

The presence of the phosphonic acid ester proposed in Formula 1 or Formula 2 in the lubricating oil formulation leads to a reduction of the friction-induced energy losses even in the mild mixed friction region due to the formation of an adsorption layer or chemisorption layer on the surface of the friction element. With increasing load, which is associated with an increase in the proportion of solid friction in the field of mixed friction, sets a reaction layer formation, as a result, the Grenzbelastbqrkeit the friction pairing is significantly increased. It is now characteristic of the lubricating oil formulation according to the invention that the layers formed in this way adhere very firmly to the sliding partners and therefore only to a limited extent is necessary, as a result of which the wear is reduced when the proposed lubricating oil formulations are used In addition to the base oil and the friction reducer η Dch characterized by formula 1 or formula 2, the lubricating oil formulation with improved trirological properties may contain individual additives or additive packages containing other lubricant properties such as aging stability, oxygenation and dispersion behavior, corrosion protection, flow properties The nature of the base oil and the formulation of the additive package depend on the intended use of the lubricating oil.

Ausführuiigsbeispiele

The lubricating oil formulation according to the invention having improved tribological properties will be described in more detail below by way of examples.

example 1

A highly refined mineral oil with a viscosity of Vi ₀ = 40 mm Vs and unsatisfactory friction behavior in the mixed friction region was treated with 1% by weight of alkylamino-bis-methylenephosphonic acid ester of the formula

C, ₂ H ₂ 5-N [-CH ₂ -PO (-O-CH ₂ -CH (-C ₂ H ₆ ) -C ₄ H 9) ₂ ] ₂

added. When examining the lubricating oil formulation on the well-known Alnern-Wieland oil testing machine (see Table t), a reduction in friction from the base oil can be demonstrated. At the same time load bearing capacity is doubling. The breaking load Fg ₁ is 11 kN compared to 5kN for the base oil.

Table 1: Friction coefficients μ of the Almen-Wieland oil testing machine with stepwise load application

Load in kN 1 3 CJL 7 9 11 μ base oil p base oil + additional reduction of μ in% 0.105 0.085 19 0.097 0.086 11.5 0.096 0.079 18 0.078 0,076 0.082

Example 2

The base oil according to Example 1 was 1% by weight of the alkylamino-bis-methylenephosphonic esters of the formula

C, 2H ₂₆ -N [-CHr-PO (-C ₂ H ₆ ) ₂ ] ₂

added. The testing of this lubricating oil formulation by means of the Almen-Wieland oil testing machine revealed the reductions in the friction numbers illustrated in Table 2, whereby the load bearing capacity was even increased to three times (breaking load: 15 kN).

Table 2: Friction coefficients μ of the Almen-Wieland oil testing machine with stepwise load application

Load in kN 1 3 5 7 9 11 13 15 Reduction of μ in% 0.105 0.05 52 0.097 0.075 23 0.096 0.066 31 0,065 0,061 0.062 0.064 0.059

0.20 0.74 1.35 1.50 1.60 1.80 0.05 0.16 0.32 0.42 0.55 0.63 75 78 76 72 66 65

The cylindrical lubricant ZA-2 known from the literature (Schmierungstechnik, Berlin 15 (1984) 6, pp.169-173) was used to investigate the antiwear effect of the new lubricant formulation, which is suitable for testing lubricants under sliding friction under mixed friction conditions By means of the lubricating oil formulation according to the invention, the cylinder-ball test pairing was significantly reduced by measuring the wear volume V _v on the friction partner ball.

Trbelle 3: Wear volume V _{v of} the friction partner ball of the cylinder apparatus ZA-2

Load in N 10 30 5C) 70 90 110

V _v base oil in 10 ~ ³ mm ³

V _v base oil + additive in 1O ^-3 mm ³

Reduction of V _v in%

Example 3

A fully formulated multigrade diesel engine oil of the viscosity class SAE 15 W 40 is used for the verbesberunc; of its tribological properties in the mixed friction region 1% by weight of alkylamino-bis-methylenephosphonic acid ester of the formula

C ₁₂ H _{2 S} -N [-CH _r -PO (-O-CH _r -CH (-C ₂ H _s hC ₄ H ₉ ) ₂ ] ₂

added. This lubricating oil formulation shows a significant reduction in friction losses on the Almen-Wieland oil testing machine. Under the conditions of a test method developed especially for the testing of friction modifiers (continuous load application up to 7.5kN within 7.5 minutes of trial time and then constant load at 5kN), the friction coefficient μ = after 60 minutes of trial time for the traditional lubricating oil 0.095, while in the lubricating oil formulation according to the invention a coefficient of friction of μ = 0.083 is measured. With the gradual increase in load on this apparatus, a reduction in friction is observed over a wide load range (see FIG. This can also be demonstrated in the long-term test (50 hours) on the cylinder apparatus ZA-2, see FIG. 2. Here, the pairing test cylinder pin at a normal load of 50 N which corresponds to a surface load of 104MPa and a speed of 200min " ¹ worked.

Also, the wear behavior of the engine oil is improved by the new formulation, as the measurements on the cylinder apparatus ZA-2 (cylinder-Kugol test pairing) prove (see Fig. 3). Thus, the improvement of the tribological behavior of the lubricating oil formulation to be protected has been sufficiently proven.

Example 4

A single-grade diesel engine oil, which conforms to the SAE 10 W viscosity class and comes close in performance to CB, became the additive

C, ₂ H ₂₆ -N [-CH ₂ -PO (-CH ₂ -CH (-C ₂ H ₅ > -C ₄ H _{£ I} ) ₂ ] ₂

in a concentration of 1% by weight of the friction modifier. The friction-enhancing effect of the new lubricating oil formulation was demonstrated on a diesel engine dynamometer. It was tested on the engine 4 VD 8,8 / 8,5-1 SRF.

In the tow attempt with dom warm engine was in the oil sump temperature range from 7O ⁰ C to 110 ° C and in the speed range of 800min '' to 3400min '' the average average power loss P _n , measured in comparison to the oil without the inventive addition of the friction modifier. The reduction in the power loss AP _n , was different depending on the speed range (see Fig.4) and was on average 1.4%.

In order to demonstrate the effect of the friction reduction on the fuel consumption of the engine, the diesel engine was operated in the ignited condition under analogous experimental conditions and the fuel consumption at an oil sump temperature of 9O ⁰ C in the speed range between 1600min '' and 3000min '' measured under full load conditions. The experiments started with the conventional engine oil without friction modifier. Then, after thorough rinsing, the motor oil produced according to the invention was tested.The average values from several batches, depending on the rotational speed, yielded a different fuel economy Ag _eo when using the lubricating oil according to the invention (see FIG. : means about 1%.

Claims (3)

1. Lubricating oil formulation with improved tribological properties in Mischre- tiongebiet, characterized in that they except the base oil and optionally a conventional additive package 0.01 wt .-% to 10 Ma .-%, preferably 0.1 Ma. -% to 3Ma .-% of a Alkylaminomethylenphosphonsäureesters as Friction Modifier included. 2. Schmieröiforniulierung according to claim 1, characterized in that the Alkylaminomethylenphosphonsäureester an alkylamino-bis-methylenephosphonic the general formula R ¹ -N [-CHr-PO (-OR ² ) ₂ ] ₂ wherein R ^{1 is} an aliphatic hydrocarbon radical having 8-20 C atoms and R ^{2 is} an aliphatic hydrocarbon radical having 1-10 C atoms. 3. Lubricating oil formulation according to claim 1, characterized in that the Alkylaminomethylenphosphonsäureesier ei'ι Dialkylaminomethylenphosphonsäureester the general formula where R ^{3 is} an alkyl radical having straight or branched aliphatic chains having 8-20 C atoms, R ^{4 is} an alkyl radical having straight or branched aliphatic chains having 1-20 C-atoms and R ^{5 is} an aliphatic hydrocarbon radical having 1-10 C -Atoms means. For this 3 pages drawings Field of application of the invention The invention relates to a lubricating oil formulation with improved tribological properties in mixed friction region. It can be used for engine and transmission oils, in particular for light-running oils, for gear oils, but also for lubricating oils in precision engineering, optics and in mechanical and apparatus engineering, where highly friction and wear-reducing lubricating oils are required. Characteristic of the known state of the art To improve the tribological properties of lubricating oil formulations he'.naltm these various additives. So z. B. the load-bearing capacity and the emergency running properties of friction pairings by the addition of high-pressure additives (so-called extreme-pressi: ^- e Additives) improved and be lowered by special anti-wear additives wear. These EP / AW additives act through the formation of protective layers only at relatively high activation energies, which can be applied only by a large solids friction ratio with mixed friction. In the field of mild mixed friction such additives have no effect, or they can even worsen the friction behavior. Since the mild mixed friction region is becoming increasingly important in modern mechanical engineering, it is urgently necessary to improve this operating state with regard to friction energy loss and wear. For this purpose, the friction modifier (FM additives) were added as an additional component in lubricating oil formulations (see Schmierungstechnik, Berlin 16 [1985] 6, pp 164-168). They reduce friction while minimizing wear in the mild mixed friction area. The friction modifiers differ from the EP / AW additives in that they billon friction- and wear-reducing adsorption, reaction, polymer or alloy layers even at lower activation energy. As friction modifiers for lubricating oil formulations, a variety of different classes of chemical compounds (fluorinated hydrocarbons, carboxylic acid esters, amines, imides, N-containing heterocycles, boric acid derivatives, etc.) have been proposed in the literature.