AU654603B2

AU654603B2 - Lubricating oil compositions

Info

Publication number: AU654603B2
Application number: AU30324/92A
Authority: AU
Inventors: Grenville Holt; Bruce Lawrence John Murray
Original assignee: BP PLC
Current assignee: BP PLC
Priority date: 1992-01-22
Filing date: 1992-12-22
Publication date: 1994-11-10
Anticipated expiration: 2012-12-22
Also published as: AU3032492A; GR3022747T3; JPH05295383A; FI107052B; FI930241A; CA2086345C; NO305761B1; GB9201338D0; ES2098464T3; NO930192D0; ATE149559T1; SG46151A1; EP0552554A1; DE69217907T2; CA2086345A1; DK0552554T3; NZ245717A; JP3406339B2; ZA9374B; EP0552554B1

Abstract

This invention relates to a lubricating oil composition which has a major proportion of a biodegradable base fluid which is a blend of (a) at least one ester of isotridecyl alcohol and a mono-, di or polycarboxylic acid, and (b) at least one hydrocarbon oil which has no more than 10%w/w of aromatic hydrocarbons, the rest being aliphatic. The proportion of (a) in the blend is from 25-55%w/w. The biodegradability of the base fluid renders the composition more environmentally friendly.

Description

;i 1; 7 i I r r 654603 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1990 REGULATION 3.2 BPO 7936 0*

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0* ,i *5 *i *i S Name of Applicant: Actual Inventor/s: Address for Service: THE BRITISH PETROLEUM COMPANY p.l.c.

GRENVILLE HOLT; and BRUCE LAWRENCE JOHN MURRAY E.F. WELLINGTON CO., Patent and Trade Mark Attorneys, 312 St. Kilda Road, Melbourne, 3004, Victoria.

Invention Title: "LUBRICATING OIL COMPOSITIONS" Details of Associated Provisional Applications Nos: The following statement is a full description of this invention 11 0 including the best method of performing it known to us.

1 1, Br 11 i/4 I C -1 r*u I i "i i II Case 7936(2) 1A The present invention relates to environmentally friendly lubricating oil compositions for automotive engines. Lubricating oil compositions for use in automotive engines are well known.

These compositions usually contain a base fluid which may comprise mineral oils, hydrocarbon oils and/or synthetic fluids and conventional additives such as viscosity index (hereafter "VI") improvers, anti-oxidants, corrosion inhibitors, dispersants, anti-wear additives and sludge control agents. In recent years, automotive engine oil development has seen a steady trend towards t 10 lower viscosity multigrades, principally to improve:fuel I efficiency. The predominant viscosity grade has moved from a typically 20W/50 oil to a 10W/40 or a 5W/40 oil. The manufacturers of automotive engine equipment have also tightened the St" specifications for such oils in terms of oil consumption, bearing protection and shear stability. This has meant that the engine lubricant has had to become lower in volatility and more shear It S' cstable so that these thinner oils stay in the specified grade band t' I longer. As a result, lubricating oils compositions based solely on conventional solvent refined mineral oils are no longer adequate to c C 20 meet these stringent performance requirements. To meet these performance requirements, a growing demand has arisen for "special" base oils possessing superior qualities of volatility, VI and pour point. These special base oils have- a VI above 120 and the requirement is primarily met by the use of paraffinic base oils which include inter alia oils based on hydrocracked wax 1 e Ii '2distillates. It has also been suggested to use blends of such hydrocracked wax distillates with aliphatic esters in order to improve the performance of such base oils. These prior art compositions usually contain 80% w/w or more of a hydrocarbon or mineral oil and upto 20% w/w of an aliphatic carboxylic acid ester in the base fluid. Such compositions, whilst being very efficient and being to some extent biodegradable, still leave room for improvement.

It has now been found that base oil blends can be formulated which not only improve the biodegradability thereof but achieve the same without loss of performance at the same time exhibiting relatively lower emissions, lower fuel consumption and lower oil consumption.

Accordingly, the present invention is a lubricating oil composition which has a major proportion of a base fluid which fluid comprises a blend of: a) isotridecvl dodecane dioate; and b) at least one hydrocarbon oil comprising upto 99.5% w/w of aliphatic hydrocarbons and no more than 10% w/w aromatic hydrocarbons such that the total of aliphatics and aromatics is 100% wherein the amount of component in the blend is in the range from 25-55% w/w.

The hydrocarbon oil component in the blend suitably is a hydrocracked wax distillate. More specifically, such hydrocarbon oils can contain upto 99.5% w/w, preferably upto 97% w/w, of aliphatic hydrocarbons and no more than 10% w/w of 'tC C L C C S

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V C C: C ii 3 aromatic hydrocarbons. The expression "aliphatic hydrocarbons" as used herein and throughout the specification is meant to include open chain aliphatic hydrocarbons as well as cycloaliphatic hydrocarbons such as e.g. naphthenic hydrocarbons. The total polycyclic aromatic hydrocarbons in the hydrocarbon oil is suitably less than 10 ppm, preferably less than 5 ppm and more preferably less than 1 ppm. Typically such hydrocarbon oil contains from 92-97% w/w of aliphatics and 3-8% w/w of aromatics.

The hydrocarbon oil component in the blend is suitably prepared by feeding a waxy distillate through a hydrocracker at 70-95% conversion under elevated temperature and hydrogen pressure.

In the first stage of this hydrocracker, sulphur and nitrogen compounds are removed and in the second stage the aromatics are hydrogenated to naphthenes; the hydrogenated products including the naphthenes are cleaved and rearranged to produce a controlled range of paraffins and isoparaffins. Fuels and lubricant products are separated by atmospheric distillation from the resultant hydrocracked products and the 5-35% heavy component is the hydrocarbon fraction use( \s the hydrocarbon oil component in f cc 20 the blend. A product produced by this method is substantially free c of any unsaturates. This feedstock can be further refined, if cr re necessary, by conventional techniques such as additional fractionation, extraction or dewaxing to obtain the finished C product. The resultant hydrocarbon oil has the following physical chi 'iteristics: C6o.dr (ASTM D 1500) 1.5 Max Density (ASTM 1298) 0.83 (ASTM D 445) 17.28 KV(100°C)/cSt (ASTM D 445) 3.99 4.22 VI (ASTM D 2270) 123 128 Pour point/°C (ASTM D 97) -24 -27 S (XRF NFM 07053) 0.08 0.15 Total N/ppm ca 12 Aromatics by HPLC/% ca 7.7 Aliphatics By HPLC/% ca 92.3 i 4 ttt C C C C CC Ic tt CO C

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C C Polycyclic aromatics/ppm 0.1 Of the aliphatic hydrocarbons in this hydrocarbon oil component about 20% w/w comprises isoparaffins having an average carbon number of about 27.

The relative amounts of the ester component and the hydrocarbon oil component in the base fluid within the specified ranges above will depend upon the nature of the two components and their relative viscosities. For instance, if the hydrocarbon component is within the physical characteristic specification defined above, the amount of the ester component that is, isotridecyldodecanedioate, in the blend may suitably vary from 30-50% w/w, preferably from 40-50% w/w.

In addition to the above blended base fluid, the lubricating composition of the present invention comprises minor proportions of conventional additives which include inter alia the following: one or more sludge dispersants, one or more VI improvers, one or more anti-wear additives, and one or more anti-oxidants. Typically, the additive package used is known to comprise components which meet the stringent requirements of an API Performance Classification "SG".

20 These requirements include successful testing in the following categories: rust test, dispersancy test, piston varnish test, low temperature sludge test and wear test. Such additives are commercially available as an additives package sold e.g. as an "SG Additive Package" under the names GBX 2900 and GBX 2905 (both ex Adibis Ltd, UK). Such an additive package suitably forms from 10-20% w/w, preferably from 11-16% w/w of the formulated lubricating composition. Examples of compounds that may be present in such a package include anti-rust agents such as the overbased calcium or magnesium sulphonates or phenates; anti-wear agents such as the zinc dithiophosphates, preferably the zinc dialkyl dithiophosphates containing 5-15% w/w phosphorus (normally prepared using a mixture of secondary alcohols and representing 0.05% w/w of phosphorus, typically 0. -0.14% phosphorus in the finished oil); ashless dispersancy age ts such as derivatives of long chain hydrocarbon substituted succinimides, especially the polyisobutenyl II 5 succinimides; and sludge dispersants which are oil soluble salts such as amides, imides, oxazolines and esters of mono- or di-carboxylic acids or anhydrides.

The anti-oxidants typically contain phenolic compounds and a typical antioxidant is commercially available as ADX 545A (ex Adibis Ltd). The anti-oxidants are suitably present in an amount from 0.01-5% w/w, preferably from 0.1-2.0% w/w of the formulated lubricating composition.

The lubricating compositions also contain one or more VI improvers. Examples of such VI improvers include polymethacrylate type dispersants commercially sold as Plexol 1420 VX (Regd Trade Mark, ex Rohm GmbH) and hydrotreated polyisoprenes commercially sold as Shellvis 200 (Regd Trade Mark, ex Shell UK Ltd).. In the case of the latter, it may used as a solution in the hydrocarbon oil component above. The VI improvers are suitably present in an amount from 2 to 5% w/w of the formulated lubricating composition.

Thus a typical formulated lubricating composition can be represented by the following components in w/w SG Additives Package (GBX 2905, ex Adibis Ltd) 15.4 20 ADX 545A (anti-oxidant, ex Adibis Ltd) Plexol* 1420 (VI improver, ex Rohm GmbH) 3.1 Shellvis* 200 (VI improver, 10% soln, ex Shell UK Ltd) Isotridecyldodecanedioate 22.59 and Hydrocarbon oil** 52.71 Registered Trade Mark The hydrocarbon oil is a hydrotreated wax distillate containing 92.3% w/w aliphatics and 7.7% w/w aromatics which is substantially free of any unsaturates and had a polycyclic aromatic content of about 0.1 ppm. An oil of this type is 30 described above.

Variations of the formulated lubricating composition shown above can also be formulated in which the relative amounts of ester and hydrocarbon oil are 32.28% and 49.32% respectively or (C) 39.5% each.

It was found that the performance of the lubricatinq t444 4414 II t I

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It I I I i i't I 1 It t IF I 4 Z4 Ti IF-_ I I ,1 6 compositions formulated in this manner upon engine testing showed relatively lower emissions, lower fuel consumption, lower oil consumption and low nitrogen oxides emission. In addition, the formulated lubricating compositions according to the present invention were at least 80% biodegradable as measured by the CEC standard test procedure. The present invention is further illustrated with reference to the following Examples: Examples General A base fluid was prepared using isotridecyldodecanedioate, and a hydrocracked wax distillate having the following physical characteristics: Property Typical Specification Test Method Colour 1.5 max ASTM D 1500 Density 0.83 ASTM D 1298 KV 40/cSt 17.28 ASTM d 445 KV 100/cSt 3.99 ASTM d 445 VI 128 ASTM D 2270 Vt" V V Lt tt Ve V t C V t Q

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Ct PMC/'C 220 ASTM Pour Point -27 ASTM 20 Demulse/mins <5 NFT* Noack volatility/% 15.8 DIN Sulphur/% 0.08 XRF CA/% 2 Bran *Correlates with ASTM D 1401 This hydrocarbon oil was used to prepare formul oil compositions according to the formulation in (A) following Examples 1-3.

Example 1 SG Additive Package (GBX 2905, ex Adibis Ltd) 30 ADX 545A (Anti-oxidant, ex Adibis Ltd) Plexol* 1420 (VI improver, ex Rohm GmbH) Shellvis* 200 (VI improver, 10% solution, ex Shell UK Ltd) Isotridecyl dodecanedioate Hydrocarbon oil (as above) *Registered Trade Mark o D 93 D 97 60-125 51581 NFM 07053 des Method ated lubricating in the 15.4% w/w 1.0% w/w 3.1% w/w 6.0% w/w 22.59% w/w 52.71% w/w f -7 The formulation was prepared using standard lubricant blending techniques described e.g. in "Lubricants and Related Products" by D Klamann, published by Verlag Chemie, 1984.

The formulated composition hui the following characteristics: Property Limits Methods Viscosity 100 0 C 13.6-14.5 cSt ASTM D 445 Viscosity 40°C 75.0-83.0 cSt ASTM D 445 Viscosity -25°C <3500 cP ASTM D 2602 Noack volatility 8.5-11.0% DIN 51581 Biodegradability >80% CEC-L-33-T-82 Calcium 0.300-0.332 ICP Phosphorus 0.102-0.114 ICP Zinc 0.105-0.135 ICP Example 2 SH Additive Package (eg OS 99099, ex Lubrizol Ltd) 15% w/w Viscoplex* 2540 (VI Improver, ex Rohm GmbH) 3.0% w/w Shellvis* 201 (VI Improver, ex Shell UK Ltd) 3.8% w/w Isotridecyl dodecanedioate 38.1% w/w Hydrocarbon oil (as above) 40.1% w/w 20 *Registered Trade Mark The formulated composition had the following characteristics: Property Limits Method Viscosity 100*C 14.0 cSt ASTM D445 Viscosity -25°C 3200 cP ASTM D2602 Noack volatility 10.7% DIN 51581 Biodegradability 87% CEL-L-33-T-82 Calcium content 0.283 ICP Phosphorus content 0.119 ICP .inc content 0.128 ICP Example 3 SG Additive Package (eg GBX2905, ex Adibis Ltd) 16.4% w/w Plwxol* 1420 (VI Improver, ex Rohm GmbH) u 3.1% w/w :GBX 2715 (VI Improver, ex Adibis Ltd) 5.0% w/w S" Isotridecyl dodecanedioate 40.0% w/w Hydrocarbon oil (as above) 35.5% w/w *Registered Trade Mark 1L,- -8 The formulated composition had the following properties: Property Limits Method Viscosity 100*C 14.5 cSt ASTM D445 Viscosity -25,*C 3300 cP ASTM D2602 Noack volatility 10.4% DIM 51581 Biodegradability 86% CEC-L-33-T-82 Calcium conter 0.310% ICP Phosphorus content 0.108% ICP Zinc content 0.125% ICP Upon standard engine testing each of the formulations described in Examples 1-3 above using the API-GS method, the following properties were observed: Property Performance Volatility Good Low Temperature Good Oxidation Stability Industrial Very Good Automotive 10W/40 Very Good 20 5W/40,50 Good Detergency SI (S SO 10W/40 Very Good 10W/40 Very Good SDispersancy 10W/40 Very Good 5W/40.:* Very Good a" Seal Compatibility e' 10W/40 Good 10W/40 Good c 30 Wear/Friction 10W/40 Very Good 10W/40 Very Good 5W/40,50 Very Good Additive Solubility Good The biodegradability of the formulated lubricating composition ii

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9 according to the present invention was tested and compared with commercially available products using the test method shown in the table above. The results are tabulated below: Present Invention 91% Mobil 1 Castrol GTX 63% Shell Gemini 66% Castrol Syntron 41% From the above it is clear that the formulated compositions according to the present invention containing the blended base fluid according to the present invention show superior properties to those of prior art, especially in respect of their biodegradability.

The matter contained in each of the following claims is to be read as part of the general description of the present invention.

S 20 t, e

Claims

1. A lubricating oil composition which has a major proportion of a base fluid, the base fluid comprising a blend of: a) isodridecyl dodecane dioate; and b) at least one hydrocarbon oil comprising up to 99.5% w/w of aliphatic hydrocarbons and no more than 10% w/w of aromatic hydrocarbons such that the total of aliphatics and aromatics is 100%, wherein the amount of component in the blend is in the range from

25-55% w/w. 2. A lubricating oil composition according to claim 1 wherein the hydrocarbon oil component is a hydrocracked wax distillate. 3. A lubricating oil composition according to claim 1 or 2 wherein the hydrocarbon oil component contains less than 10 ppm of polycyclic aromatic hydrocarbons, from 92-97% w/w of aliphatic hydrocarbons and 3-8% w/w of aromatic hydrocarbons. t 11 4 A lubricating oil composition according to any one of the preceding claims wherein the aliphatic hydrocarbons in the hydrocarbon oil component comprise about 20% w/w of isoparaffins having an average carbon number of about 27. 5. A lubricating oil composition according to any one of the preceding claims wherein the amount of the isotridecyl dodecanedioate in the blend is in the range from 30-50% w/w. 6. A lubricating oil composition according-to any one of the preceding claims wherein said composition comprises, in addition, minor proportions of one or more additives selected from: sludge dispersants, ashless dispersancy agents, VI improvers, anti-wear additives, anti-rust agents and anti-oxidants. 7. A lubricating oil composition according to claim 6 wherein the anti-rust agent is an overbased calcium or magnesium sulphonate or phenate; the anti-wear agent is a zinc dithiophosphate; the ashless dispersancy agent is a long chain hydrocarbon substituted succinimide; the sludge dispersant is an oil soluble salt such as Samides, imides, oxazolines and esters of mono- or di-carboxylic S 20 acids or anhydrides; the anti-oxidant is a phenolic:compound; and L the VI improver comprises a polymethacrylate dispersant or a hydrotreated polyisopree. 8. A lubricating oil composition according to any one of the prectding claims wherein 'said composition is at least S, 25 biodegradable as measured by the CEC standard test procedure. 9 A lubricating oil composition according to claim 1, substantially as hereinbefore described in any one of.the practical Examples. DATED this 13th day of September, 1994 30 THE BRITISH PETROLEUM COMPANY plc., By its Patent Attorneys, E F. WELLINGTON CO., S 35 Xs.- Wellington i b 0n 0 P. ii Ir -c- .Il~r- ~-I i :J i 1 :j ;I Case 7936(2) ABSTRACT This invention relates to a lubricating oil composition which has a major proportion of a biodegradable base fluid which is a blend of at Icast one ester of isotridecyl alcohol and a mono-, di or polycarboxylic acid, and at least one hydrocarbon oil which has no more than 10%w/w of aromatic hydrocarbons, the rest being aliphatic. The proportion of in the blend is from 25-55%w/w. The biodegradability of the base fluid renders the composition more environmentally friendly. Cc Cci Ct t C C D i. rt c I- c C ;i ii t r I: I L/ 1k