DE2005755A1 - Multi-range lubricating oils - Google Patents

Abstract

Multi-range lubricating oils are based on diesters with 25-28C atoms, alone or mixed with mineral oils and in latter case with at least 10% diester in the mixture, and contain a polyolefine with av. mol. wt. of 3000-20,000. The lubricating oils remains fluid and mobile at low temps. and thus no starting difficulties are experienced at low temps. in case of e.g. combustion motors.

Description

Multi-grade lubricating oils The invention relates to multi-grade lubricating oils, which are particularly characterized by the fact that they are also at a very low temperature in the wheel of a machine, e.g. 13. of an internal combustion engine, no matter how thin they are, that no starting difficulties arise, the new oils consist of the star bifunctional acids or alcohols with a total of between 25 and 28 carbon atoms and a polyolefin in the mean molecular weight range between about 30ao and 20,000 as viscosity index improvers and can also use low-aromatic mineral Contain lubricating oils and / or lubricant additives, but the diester portion Should not fall below 10%. The polyolefin in the specified molecular weight range improves the cold start readiness of such oils in a completely unexpected way: The actual cold viscosities, i.e. the measured ones, of these oils are clear below the calculated, and in any case cheaper than the underlying, no polyolefins in the specified molecular weight range containing Oiling, as can easily be determined by measuring in the CCS device according to AST D 2602.

Engine lubricating oil based on the star of dicarboxylic acids or from diols alone or in a mixture with mineral oils rind mainly because of their excellent cold start properties are gaining more and more input.

In order to give such oils high heat resistance at the same time the heat viscosity is increased by the addition of polymers. As a result, they lose Ester oils largely retain their Newtonian properties, and those at higher shear rates, which should correspond to the application of the lubricant are measured at low temperatures sometimes a factor of 2 to 3 higher than that according to the usual method (Walther-Ubbelohde DIN 51562) extrapolated viscosities. This factor increases with falling temperature However, at a given temperature, it generally increases with the molecular weight of the V.I. improver.

The addition of polyolefins according to the invention, z, B.

of polyisobutylene molecular weight range from 3,000 to 20,000 that Range has the surprising and technically important effect that the higher range Shear gradients measured cold viscosities are lower than those according to DIN 51562 extrapolated: Example 1 A multigrade oil rçE 20W / 50 with good cold properties (cold start up to about -150C) in addition to good heat resistance (5 cSt at 1356C) consists: 25% by weight trimethyladipic acid di (n-C9) ester 59% by weight Mineral oil (100 V.I. paraffin-based solvent raffinate) V 210 F = 11.3 cSt 10 wt. Polyisobutylene A (average molecular weight = 3000) 6% by weight additive (detergent-dispersant inhibitor to achieve the "motor performance MS") Viscosity: Oo F extrapolated (cSt) 9.600 from V 210 F and V 100 F 0 ° F CCS device ASTM D 2602 (converted into cSt) 8.830 Ratio CCS / extrapolated 0.92 Example 2 For the production of an aircraft engine lubricating oil with a viscosity of 5 cSt at 210 ° F, a thermostable diester of n cSt at 210 ° F, which is essentially Newtonian fluid, with a dilution from the same diester and polyisobutylene, use. Such a blending component consists e.g. of: 75% trimethyladipic acid -di (n-C ,: -ester 25% polyisobutylene with a molecular weight of approx. 18,000.

This has the following properties: V 210 ° F = 15.5 cSt V.I. = 155 V -20 ° F = 2000 c9t extrapolated or 1740 cSt measured according to ASTM D 2602.

The ratio of measured to extrapolated viscosity at 200 F is therefore 0187.

A mixture of 26 ß of the above mixed component and 74 s of the starting diester has V 2100 F = 5.0 cSt at V.I. = 170 and behaves according to the proportion of Mixing component also in the viscosity at the shear rate of the ASTM method D 2602 and cheaper at -20 ° F. (However, the low viscosity value can Do not measure on the device while taking measurements at a temperature lower than -200F are not permitted.)

Claims (1)

Claim: multigrade lubricating oils based on Die stern with 25 to 28 carbon atoms alone or in a mixture with mineral oils, in the latter case with at least 10% diester in the mixture, characterized by a content of polyolefin with an average molecular weight between about 3000 and 20,000.