Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic sulfur compound – wherein the sulfur is single bonded...
Patent
1996-12-13
1998-03-10
Howard, Jacqueline V.
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic sulfur compound, wherein the sulfur is single bonded...
508241, 508503, 508580, C10M16300
Patent
active
057261342
DESCRIPTION:
BRIEF SUMMARY
This invention relates to lubricating oil compositions and in particular to crankcase lubricating oil compositions for use as passenger car motor oils and heavy duty diesel oils.
Lubricating oils as used in, for example, the internal combustion engines of automobiles or trucks are subjected to a demanding environment during use. Combustion and/or oxidation products from burning and/or oxidation of fuel, lubricating oil and nitrogen in the air as well as products of the thermal and oxidative degradation of hydrocarbon lubricating oils and additives thereto tend to concentrate in the crankcase oil. These products tend to form oil-insoluble products that either surface coat metal parts with lacquer or varnish-like films or settle out as viscous sludge deposits or form ash-like solids or carbonaceous deposits. Any of these deposits can restrict and even plug grooves, channels and holes provided for lubricant flow to moving surfaces requiring lubrication. Lubricating oil formulations are therefore formulated to not only to reduce the magnitude of these oil insoluble products but also to minimise their impact by keeping them in suspension through the use of dispersants and/or to re-suspend them with a a detergent which also acts to neutralise acidic products.
Dispersant additives for lubricating oils are typically ashless materials which have a polymeric hydrocarbon backbone and functional groups capable of associating with particles to be dispersed and which are connected to the polymer backbone via a bridging group. Widely used conventional dispersants are those based on polyisobutene substituted succinic acids or arthydrides which are reacted with hydroxyl compounds or amines, such as for example polyisobutenyl succinic arthydrides reacted with polyamines, for convenience referred to as PIBSA/PAM ashless dispersants.
Typically the detergents used in lubricating oils are neutral and/or overbased alkaline earth metal salts of carboxylic acids, substituted phenols and their sulfurised derivatives, substituted salicylic acids and substituted sulfonic acids.
Modern lubricating oils and especially heavy duty diesel oils are facing increasingly stringent requirements for deposit control and liner wear reduction. In the prior art and historically detergents have been the most effective in reducing the high temperature deposits which are produced in heavy duty diesel engines and have also been effective in preventing or keeping to a minimum bore polish. There has also been an increasing pressure on formulators to ensure that their products have the required environmental properties. One of these properties is to provide additives and compositions which can be used in low ash lubricating oil formulations. One of the main sources of ash are the metal containing detergents.
There is also a strong desire to be able to provide lubricating oil compositions and concentrates which have universal application as both heavy duty diesel and also passenger car motor oils.
EP 0277729 B1 describes lubricating oil additive compositions which are said to provide wear protection at reduced phosphorus levels when used to formulate oils. The composition comprises a specific type of ZDDP, a succinamide dispersant which is derived from polybutene and propoxylated hexamethylenediamine, boron, and high base metal sulfonates and/or phenates as well as other additives.
Lubricating oil formulations which are based on widely used conventional dispersants such as PIBSNPAM dispersants whilst having acceptable performance in relation to heavy duty diesel applications have shortcomings in the passenger car motor oil area where they are unable to easily meet the requirements of the Sequence VE engine test the purpose of which is to evaluate an oils sludge wear and varnish performance under high-, medium- and low-temperature conditions. These requirements are usually met by using a higher treat rate of the dispersant however this increase can result in viscosity problems with a consequential reduction in formulating flexibility.
A new class of ashless
REFERENCES:
patent: 5277833 (1994-01-01), Song et al.
patent: 5328620 (1994-07-01), Ripple
patent: 5435926 (1995-07-01), Gutierrez et al.
Exxon Chemical Patents Inc.
Howard Jacqueline V.
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