Two-stroke engine oils
AssigneeBP Chemicals Limited
InventorsJohn McMahon, John D. Fotheringham
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Abstract
This invention relates to a two-stroke engine oil which comprises polybutene base oils which are either very low in or are substantially free of n-butenes in the polymer backbone. The absence of n-butenes in the polybutenes significantly reduces smoke emission in exhaust gases generated by the use of the engine oil. Polybutenes such as ULTRAVIS.RTM. which are substantially free of chlorine and have a high degree of terminal unsaturation are particularly preferred.
Claims9
A two-stroke engine oil comprising a mineral oil and a polybutene polymer or mixtures of polymers of molecular weight (Mn) from 300-2000 characterised in that the proportion of n-butenes in the polymer backbone, as defined by the ratio of the infra-red absorbance of the --CH.sub.2 CH.sub.2 -- n-butene units in the polymer at 740 cm.sup.-1 to that of the CH--H overtone absorbance between 4315 and 4345 cm.sup.-1, is <0.2 for polybutenes with a value of Mn equal to or <700, and <0.12 for polybutenes with Mn>700.
Dependencies are inferred from the claim text.