Long life medium and high ash oils with enhanced nitration resistance

A long life lubricating oil as evidenced by a reduction in viscosity increase, oxidation and nitration, comprises a major amount of a base oil of lubricating viscosity and a minor amount of a mixture of high TBN, medium TBN and low/neutral TBN detergents wherein metal salicylate detergent is at least one of the medium or low/neutral TBN detergents.

FIELD OF THE INVENTION
 The present invention relates to medium and high ash engine oils of
 extended life as evidenced by a reduction in viscosity increase, oxidation
 and nitration, comprising a base oil of lubricating viscosity and a
 particular combination of detergents.
 BAC.KGROUND OF THE INVENTION
 Natural gas fired engines are large, having up to 16 cylinders, and often
 generating between 500-3000 HP. The engines are typically used in the Oil
 and Gas industry to compress natural gas at well heads and along
 pipelines. Due to the nature of this application, the engines often run
 continuously near full load conditions, shutting down only for maintenance
 such as for oil changes. This condition of running continuously near full
 load places severe demands on the lubricant. Indeed, since the lubricant
 is subjected to a high temperature environment, the life of the lubricant
 is often limited by oil oxidation processes. Additionally, since natural
 gas fired engines run with high emissions of oxides of nitrogen
 (NO.sub.x), the lubricant life may also be limited by oil nitration
 processes. Therefore, it is desirable for gas engine oils to have long
 life through enhanced resistance to oil oxidation and nitration.
 The combustion of diesel fuel often results in a small amount of incomplete
 combustion (e.g., exhaust particulates). The incombustibles provide a
 small but critical degree of lubrication to the exhaust valve/seat
 interface, thereby ensuring the durability of both cylinder heads and
 valves. The combustion of natural gas is often very complete, with
 virtually no incombustible materials. Therefore, the durability of the
 cylinder head and valve is controlled by the properties of the lubricant
 and its consumption rate. For this reason, gas engine oils are classified
 according to their ash content, since it is the lubricant ash which acts
 as a solid lubricant to protect the valve/seat interface. The oil industry
 has accepted guidelines which classify gas engine oils according to their
 ash level. The classifications are:

Ash Designation Ash Level (wt %. ASTM D874)
 Ash less Ash &lt; 0.1%
 Low Ash 0.1 &lt; Ash &lt; 0.6
 Medium Ash 0.6 &lt; Ash &lt; 1.5
 High Ash Ash &gt; 1.5
 The ash level of the lubricant is often determined by its formulation
 components, with metal-containing detergents (e.g., barium, calcium) and
 metallic-containing antiwear additives contributing to the ash level of
 the lubricant. For correct engine operation, gas engine manufacturers
 define lubricant ash requirements as part of the lubricant specifications.
 For example, manufacturers of 2-cycle engines often require the gas engine
 oil to be Ashless in order to minimize the extent of harmful deposits
 which form on the piston and combustion chamber area Manufacturers of
 4-cycle engines often require the gas engine oils to be Low, Medium or
 High Ash to provide the correct balance of engine cleanliness, and
 durability of the cylinder head and valves. Running the engine with too
 low an ash level will likely result in shortened life for the valves or
 cylinder head. Running the engine with too high an ash level will likely
 cause excessive deposits in the combustion chamber and upper piston area.
 Gas engine oil of enhanced life as evidenced by an increase in the
 resistance of the oil to oxidation, nitration and deposit formation is the
 subject of U.S. Pat. No. 5,726,133. The gas engine oil of that patent is a
 low ash gas engine oil comprising a major amount of a base oil of
 lubricating viscosity and a minor amount of an additive mixture comprising
 a mixture of detergents comprising at least one alkali or alkaline earth
 metal salt having a Total Base Number (TBN) of about 250 and less and a
 second alkali or alkaline earth metal salt having a TBN lower than the
 aforesaid component. The TBN of this second alkali or alkaline earth metal
 salt will typically be about half or less that of the aforesaid component.
 The fully formulated gas engine oil of U.S. Pat. No. 5,726,133 can also
 typically contain other standard additives known to those skilled in the
 art, including dispersants (about 0.5 to 8 vol %), phenolic or aminic
 anti-oxidants (about 0.05 to 1.5 vol %), metal deactivators such as
 triazoles, alkyl substituted dimercaptothiadiazoles (about 0.01 to 0.2 vol
 %), anti wear additives such as metal di thiophosphates, metal
 dithiocarbamates, metal xanthates or tricresylphosphates (about 0.05 to
 1.5 vol %), pour point depressants such as poly (meth) acrylates or alkyl
 aromatic polymers (about 0.05-0.6 vol %), anti foamants such as silicone
 antifoaming agents (about 0.005 to 0.15 vol %), and viscosity index
 improvers, such as olefin copolymers, polymethacrylates, styrene-diene
 block copolmyers, and star copolymers (up to about 15 vol %, preferably up
 to about 10 vol %).
 SUMMARY OF THE INVENTION
 The present invention relates to a lubricating oil of extended life as
 evidenced by reductions in viscosity increase, oxidation and nitration,
 relative to current commercial and reference oils, which comprises a major
 amount of a base oil of lubricating viscosity and a minor amount of a
 mixture of metal salicylate detergent(s) and a metal sulfonate and/or
 metal phenate detergent(s). The present lubricating oil would be
 particularly useful as a medium ash or high ash gas engine oil.
 DETAILED DESC.RIPTION OF THE INVENTION
 A lubricating oil composition is described comprising a major amount of a
 base oil of lubricating viscosity and a minor amount of a mixture of one
 or more metal salicylate detergent(s), and one or more metal phenate(s)
 and/or metal sulfonate detergents. Also described is a method for
 extending the life of lubricating oils as evidenced by a reduction in
 viscosity increase, oxidation and nitration by adding to the oil an
 additive comprising a mixture of one or more metal salicylate
 detergent(s), and one or more metal sulfonate(s) and/or one or more metal
 phenate(s).
 The lubricating oil base stock is any natural or synthetic lubricating base
 oil stock fraction typically having a kinematic viscosity at 100.degree.
 C.. of about 5 to 20 cSt, more preferably about 7 to 16 cSt, most
 preferably about 9 to 13 cSt. In a preferred embodiment, the use of the
 viscosity index improver permits the omission of oil of viscosity about 20
 cSt or more at 100.degree. C.. from the lube base oil fraction used to
 make the present formulation. Therefore, a preferred base oil is one which
 contains little, if any, heavy fraction; e.g., little, if any, lube oil
 fraction of viscosity 20 cSt or higher at 100.degree. C..
 The lubricating oil basestock can be derived from natural lubricating oils,
 synthetic lubricating oils or mixtures thereof. Suitable lubricating oil
 basestocks include basestocks obtained by isomerization of synthetic wax
 and slack wax, as well as hydrocrackate basestocks produced by
 hydrocracking (rather than solvent extracting) the aromatic and polar
 components of the crude. Suitable basestocks include those in API
 categories I, II and III, where saturates level and Viscosity Index are:
 Group I--less than 90% and 80-120, respectively;
 Group II--greater than 90% and 80-120, respectively; and
 Group III--greater than 90% and greater than 120, respectively.
 Natural lubricating oils include animal oils, vegetable oils (e.g.,
 rapeseed oils, castor oils and lard oil), petroleum oils, mineral oils,
 and oils derived from coal or shale.
 Synthetic oils include hydrocarbon oils and halo-substituted hydro-carbon
 oils such as polymerized and inter-polymerized olefins, alkylbenzenes,
 polyphenyls, alkylated diphenyl ethers, allylated diphenyl sulfides, as
 well as their derivatives, analogues and homologues thereof, and the like.
 Synthetic lubricating oils also include alkylene oxide polymers,
 interpolymers, copolymers and derivatives thereof wherein the terminal
 hydroxyl groups have been modified by esterification, etherification, etc.
 Another suitable class of synthetic lubricating oils comprises the esters
 of dicarboxylic acids with variety of alcohols. Esters useful as synthetic
 oils also include those made from C..sub.5 to C..sub.12 monocarboxylic
 acids and polyols and polyol ethers. Trialkyl phosphate ester oils such as
 those exemplified by tri-n-butyl phosphate and tri-iso-butyl phosphate are
 also suitable for use as base oils.
 Silicon-based oils (such as the polyakyl-, polyaryl-, polyalkoxy-, or
 polyaryloxy-siloxane oils and silicate oils) comprise another useful class
 of synthetic lubricating oils. Other synthetic lubricating oils include
 liquid esters of phosphorus-containing acids, polymeric tetrahydrofinans,
 polyalphaolefins, and the like.
 The lubricating oil may be derived from unrefined, refined, rerefined oils,
 or mixtures thereof. Unrefined oils are obtained directly from a natural
 source or synthetic source (e.g., coal, shale, or tar sand bitumen)
 without further purification or treatment. Examples of unrefined oils
 include a shale oil obtained directly from a retorting operation, a
 petroleum oil obtained directly from distillation, or an ester oil
 obtained directly from an esterification process, each of which is then
 used without further treatment. Refined oils are similar to the unrefined
 oils except that refined oils have been treated in one or more
 purification steps to improve one or more properties. Suitable
 purification techniques include distillation, hydrotreating, dewaxing,
 solvent extraction, acid or base extraction, filtration, and percolation,
 all of which are known to those skilled in the art. Rerefined oils are
 obtained by treating refined oils in processes similar to those used to
 obtain the refined oils. These rerefined oils are also known as reclaimed
 or reprocessed oils and often are additionally processed by techniques for
 removal of spent additives and oil breakdown products.
 Lubricating oil base stocks derived from the hydroisomerization of wax may
 also be used, either alone or in combination with the aforesaid natural
 and/or synthetic base stocks. Such wax isomerate oil is produced by the
 hydro-isomerization of natural or synthetic waxes or miuxtures thereof
 over a hydro-isomerization catalyst.
 Natural waxes are typically the slack waxes recovered by the solvent
 dewaxing of mineral oils; synthetic waxes are typically the wax produced
 by the Fischer-Tropsch process.
 The resulting isomerate product is typically subjected to solvent dewaxing
 and fractionation to recover various fractions of specific viscosity
 range. Wax isomerate is also characterized by possessing very high
 viscosity indices, generally having a VI of at least 130, preferably at
 least 135 and higher and following dewaxing a pour point of about
 -20.degree. C.. and lower.
 The production of wax isomerate oil meeting the requirements of the present
 invention is disclosed and claimed in U.S. Pat. Nos. 5,049,299 and
 5,158,671.
 The detergent is a mixture of one or more metal salicylate detergents with
 one or more metal sulfonates and/or one or more metal phenates. The metals
 are any alkali or alkaline earth metals, e.g., calcium, barium, sodium,
 lithium, potassium, magnesium, more preferably calcium, barium and
 magnesium. It is a feature of the present lubricating oil that each of the
 metal salts or groups of metal salts used in the mixture has a different
 TBN as compared with the other metal salts or groups of metal salts in the
 mixture.
 Thus, the mixture of detergents comprises a first metal salt or group of
 metal salts selected from the group consisting of one or more metal
 sulfonate(s), salicylate(s), phenate(s) and mixtures thereof having a high
 TBN of greater than about 150 to 300 or higher, preferably about 160 to
 300, used in an amount in combination with the other metal salts or groups
 of metal salts (recited below) sufficient to achieve a lubricating oil of
 at least 0.65 wt % sulfated ash content, a second metal salt or group of
 metal salts selected from the group consisting of one or more metal
 salicylate(s), metal sulfonate(s), metal phenate(s) and mixtures thereof
 having a medium TBN of greater than about 50 to 150, preferably about 60
 to 120, and a third metal salt or group of metal salts selected from the
 group consisting of one or more metal sulfonate(s), metal salicylate(s)
 and mixtures thereof identified as neutral or low TBN, having a TBN of
 about 10 to 50, preferably about 20 to 40, the total amount of medium plus
 neual/low TBN detergent being about 0.7 vol % or higher (active
 ingredient), preferably about 0.9 vol % or higher (active ingredient),
 most preferably about 1 vol % or higher (active ingredient), wherein at
 least one of the medium or low/neutral TBN detergent(s) is metal
 salicylate, preferably at least one of the medium TBN detergent(s) is a
 metal salicylate. The total amount of high TBN detergents is about 0.3 vol
 % or higher (active ingredient), preferably about 0.4 vol % or higher
 (active ingredient), most preferably about 0.5 vol % or higher (active
 ingredient). The mixture contains salts of at least two different types,
 with medium or neutral salicylate being an essential component. The volume
 ratio (based on active ingredient) of the high TBN detergent to medium
 plus neutral/low TBN detergent is in the range of about 0.15 to 3.5,
 preferably 0.2 to 2, most preferably about 0.25 to 1.
 The mixture of detergents is added to the lubricating oil formulation in an
 amount up to about 10 vol % based on active ingredient in the detergent
 mixture, preferably in an amount up to about 8 vol % based on active
 ingredient, more preferably up to about 6 vol % based on active ingredient
 in the detergent mixture, most preferably between about 1.5 to 5.0 vol %,
 based on active ingredient in the detergent mixture. Preferably, the total
 amount of metal salicylate(s) used of all TBN's is in the range of between
 about 0.5 vol % to 4.5 vol %, based on active ingredient of metal
 salicylate.
 The formulation may also contain one or more of the commonly used
 additives. Thus, in addition to the recited detergents, the oil
 composition can contain one or more antioxidants phenolic, aminic or
 other), viscosity index improvers, pour point depressants,
 antiwear/extreme pressure additives, antifoamant, dyes, metal
 deactivators, etc.
 Anti-oxidants useful in the present invention may be of the phenol (e.g.,
 o,o' ditertiary alkyl phenol such as diterliarybutyl phenol), or amine
 (e.g., dialkyl diphenylamine such as dibutyl, octylbutyl or dioctyl
 diphenylamine) type, or mixtures thereof. These should be substantially
 non-volatile at peak engine operating temperatures. By substantially
 non-volatile is meant that there is less than 10% volatility at about
 150.degree. C., preferably at about 175.degree. C., most preferably at
 about 200.degree. C. and higher. The term "phenol type" used herein
 includes compounds having one or more than one hydroxy group bound to an
 aromatic ring which may itself be mononuclear, e.g., benzyl, or
 polynuclear, e.g., naphthyl and spiro aromatic compounds. Thus "phenol
 type" includes phenol per se, catechol, resorcinol, hydroquinone,
 naphthol, etc., as well as alkyl or alkenyl and sulfurized alkyl or
 alkenyl derivatives thereof and bisphenol type compounds including such
 bi-phenol compounds linked by alkylene bridges or sulfur or oxygen
 bridges. Alkyl phenols include mono- and poly-alkyl or alkenyl phenols,
 the alkyl or alkenyl group containing from about 3-100 carbons, preferably
 4 to 50 carbons and sulfurized derivatives thereof, the number of alkyl or
 alkenyl groups present in the aromatic ring ranging from 1 to up to the
 available unsatisfied valences of the aromatic ring remaining after
 counting the number of hydroxyl groups bound to the aromatic ring.
 Generally, therefore, the "phenolic type" anti-oxidant may be represented
 by the general formula:
 ##STR1##
 where Ar is selected from the group consisting of:

##STR2##
 wherein R is a C..sub.3 -C..sub.100 alkyl or alkenyl group, a sulfIr
 substituted alkyl or alkenyl group, preferably a C..sub.4 -C..sub.50 alkyl
 or alkenyl group or sulfur substituted alkyl or alkenyl group, more
 preferably C..sub.3 -C..sub.100 alkyl or sulfur substituted alkyl group,
 most preferably a C..sub.4 -C..sub.50 alkyl group, y ranges from 1 to up
 to the available valences of Ar, x ranges from 0 to up to the available
 valances of Ar-y, Q ranges from 0 to up to the available valences of
 Ar+(x+y +p), z ranges from 1 to 10, n ranges from 0 to 20, and m is 0 to 4
 and P is 0 or 1, preferably y ranges from 1 to 3, x ranges from 0 to 3, z
 ranges from 1 to 4 and n ranges from 0 to 5, p is 0 and Q is 0 or 1.
 Most preferably the phenol is a hindered phenol such as di isopropyl
 phenol, di-tert butyl phenol di tert butyl alkylated phenol where the
 alkyl substitutent is hydrocarbyl and contains between 1 and 20 carbon
 atoms, such as 2,6 di-tert butyl- 4 methyl phenol, 2,6-di-tert butyl-
 4-ethyl phenol, etc., or 2,6 di-tert butyl-4-alkoxy phenol.
 Phenolic type anti-oxidants are well known in the lubricating industry and
 to those skilled in the art. The above is presented only by way of
 exemplification, not limitation on the type of phenolic anti-oxidants
 which can be used in the present invention.
 The amine type antioxidants include diarylamines and thiodiaryl amines.
 Suitable diarylamines include diphenyl amine;
 phenyl-.alpha.-naphthylamine; phenyl-.beta.-naphthylamine;
 .alpha.-.alpha.-di-naphthylamine; .beta.-.beta.-dinaphthylamine; or
 .alpha.- .beta.-dinaphthylamine. Also suitable antioxidants are
 diarylamines wherein one or both of the aryl groups are alkylated, e.g.,
 with linear or branched alkyl groups contaning 1 to 12 carbon atoms, such
 as the diethyl diphenylamines; dioctyldiphenyl amines, methyl
 phenyl-.alpha.-naphthylamines; phenyl-.beta.-(butylnaphthyl) amine;
 di(4-methyl phenyl) amine or phenyl (3-propyl phenyl) amine
 octyl-butyl-diphenylamine, dioctyldiphenyl amine, octyl-, nonyl-diphenyl
 amine, dinonyl di phenyl amine and mixtures thereof.
 Suitable thiodiarylamines include phenothiazine, the alkylated
 phenothiazines, phenyl thio-.alpha.-naphthyl amine; phenyl
 thio-.beta.-naphthylamine; .alpha.-.alpha.-thio dinaphthylamine;
 .beta.-.beta.-thio dinaphthylamine; phenyl thio-.alpha.(methyl naphthyl)
 amine; thio-di (ethyl phenyl)amine; (butyl phenyl) thio phenyl amine.
 Other suitable antioxidants include s-triazines of the formula
 ##STR3##
 wherein R.sup.8, R.sub.9, R.sub.10, R.sub.11, are hydrogen, C.sub.1
 C.sub.20 hydrocarbyl or pyridyl and R.sup.7 is C..sub.1 to C..sub.8
 hydrocarbyl C..sub.1 to C..sub.20 hydrocarbylamine, pyridyl or
 pyridylamine. If desired, mixtures of antioxidants may be present in the
 lubricant composition of the invention. The total amount of antioxidant or
 antioxidant mixtures used ranges from about 0.05 to 2.0 vol %, preferably
 about 0.1 to 1.75 vol %, most preferably about 0.5 to 1.5 vol %.
 Viscosity index improvers useful in the present invention include any of
 the polymers which impart enhanced viscosity properties to the finished
 oil and are generally hydrocarbon-based polymers having a molecular
 weight, Mw, in the range of between about 2,000 to 1,000,000, preferably
 about 50,000 to 200,000. Viscosity index improver polymers typically
 include olefin copolymers, e.g., ethylene-propylene copolymers,
 ethylene-iso-)butylene copolymers, propylene-(iso-)butylene copolymers,
 ethylene-poly alpha olefin copolymers, polymethocrylates; styrene-diene
 block copolymers, e.g., styrene-isoprene copolymers, and star copolymers.
 Viscosity index improvers may be monofunctional or multifunctional, such
 as those bearing substitutents that provide a secondary lubricant
 performance feature such as dispersancy, pour point depression, etc.
 Viscosity index improvers are lubricant additives well known in the
 lubricant industry and to those skilled in the at The above is presented
 only by way of example and not as a limitation on the types of viscosity
 index improvers which can be used in the present invention.
 The amount of viscosity index improver used, be it mono functional or
 multifunctional, is in the amount of about 0.1 to 3 vol %, preferably
 about 0.2 to 2 vol %, most preferably about 0.3 to 1.5 vol %.
 The fully formulated lubricating oil may contain other additional, typical
 additives known to those skilled in the industry, used on an as-received
 basis.
 Thus, the fully formulated oil may contain dispersants of the type
 generally represented by succinimides (e.g., polyisobutylene succinic
 acid/anhydride (PIBSA)-polyamine having a PIBSA molecular weight of about
 700 to 2500). The dispersants may be borated or non-borated. The
 dispersant can be present in the amount of about 0.5 to 8 vol %, more
 preferably in the amount of about 1 to 6 vol %, most preferably in the
 amount of about 2 to 4 vol %.
 Metal deactivators may be of the aryl thiazines, triazoles, or alkyl
 substituted dimercapto thiadiazoles (DMTD's), or mixtures thereof. Metal
 deactivators can be present in the amount of about 0.01 to 0.2 vol %, more
 preferably in the amount of about 0.02 to 0.15 vol %, most preferably in
 the amount of about 0.05 to 0.1 vol %.
 Antiwear additives such as metal dithiophosphates (e.g., zinc dialkyl
 dithiophosphate, ZDDP), metal dithiocarbamates, metal xanthates or
 tricresylphosphates may be included. Antiwear additives can be present in
 the amount of about 0.05 to 1.5 vol %, more preferably in the amount of
 about 0.1 to 1.0 vol %, most preferably in the amount of about 0.2 to 0.5
 vol %.
 Pour point depressants such as poly(meth)acrylates, or alkylaromatic
 polymers may be included. Pour point depressants can be present in the
 amount of about 0.05 to 0.6 vol %, more preferably in the amount of about
 0.1 to 0.4 vol %, most preferably in the amount of about 0.2 to 0.3 vol %.
 Antifoamants such as silicone antifoaming agents can be present in the
 amount of about 0.001 to 0.2 vol %, more preferably in the amount of about
 0.005 to 0.15 vol %, most preferably in the amount of about 0.01 to 0.1
 vol %.
 Lubricating oil additives are described generally in "Lubricants and
 Related Products" by Dieter Klamann, Verlag C.hemie, Deerfield, Fla.,
 1984, and also in "Lubricant Additives" by C.. V. Smalheer and R. Kennedy
 Smith, 1967, page 1-11, the disclosures of which are incorporated herein
 by reference.

The present invention is illustrated further in the following nonlimiting
 examples and comparative examples.
 EXPERIMENTAL
 Lab Nitration Screener Test Results
 A lab nitration screener test was used in initial experiments to guide in
 the selection of detergents, antioxidants, and viscosity index improvers
 (VIs). The test results identify a number of parameters for assessing the
 used oil performance, including viscosity increase, oxidation, and
 nitration. All measurements are reported on a relative basis so that large
 results or values represent greater levels of lubricant degradation. Thus,
 numerically lower results represent a measure of longer oil life. In each
 test, a Reference Oil is always tested. All results are reported as a
 ratio of the result for the oil tested divided by the result for a
 Reference Oil. For example, if a tested oil has an oxidation result of
 1.0, then it has an oxidation performance equal to that of the Reference
 Oil. If the tested oil has an oxidation result less than 1.0, then the
 tested oil demonstrates oxidation performance superior to that of the
 Reference Oil.
 EXAMPLES
 Lab nitration screener test results are summarized in Table 1. Results are
 measured relative to Reference Oil B, which is a commercial medium ash gas
 engine oil based on solvent-extracted basestocks. Reference Oil B is the
 most widely sold medium ash gas engine oil in C.anada and therefore
 represents a "benchmark standard" against which other formulations useful
 as engine oils may be measured. C.omparative Oil 1 is another commercial
 medium ash gas engine oil, formulated with Oloa 1255 additive package in
 solvent-extracted basestocks. Oloa 1255 is one of the most widely sold gas
 engine oil additive packages and therefore C.omparative Oil 1 represents
 another "bench-mark standard" against which other formulations may be
 measured. C.omparative Oil 2 is a medium ash formulation blended using a
 combination of low TBN calcium sulphonate, medium TBN calcium phenate and
 high TBN calcium phenate.
 Results show that the oil of the present invention, Example 1, demonstrates
 superior performance to those of the C.omparative oils, in terms of
 reduced oxidation, nitration and viscosity increase, and superior
 performance to that of Reference Oil B in terms of reduced oxidation and
 nitration and equal to Reference Oil B for reduced viscosity increase.
 Example 1 contains a mixture of three metal salt detergents, one each from
 the group high TBN, medium TBN and low/neutral TBN detergents, wherein at
 least one metal salicylate is used as the medium or low/neutral salt
 detergent. The invention provided performance superior to that of the
 other oils that used different detergents or mixtures of detergents.
 TABLE 1
 TEST FORMULATIONS AND NITRATION TEST RESULTS
 Component Reference Comparative
 Comparative Reference Example
 (vol %) Description Oil B Oil 1
 Oil 2 Oil B* 1
 Commercial oil 100.00 -- --
 100.0 --
 Commercial oil -- 100.00 --
 -- --
 600 SN base oil -- -- 86.70
 -- --
 1200 SN base oil -- -- 2.68
 -- --
 150 SN base oil -- -- -- --
 4.35
 600 SN base oil -- -- -- --
 86.20
 135 TBN Ca phenate detergent -- -- 2.47
 -- --
 Neutral Ca sulphonate (26 TBN) -- -- 0.81
 -- 0.81
 Dispersant -- -- 4.00
 -- --
 Metal deactivator -- -- 0.05
 -- --
 ZDDP -- -- 0.29
 -- --
 Antifoamant -- -- 0.05
 -- --
 Pour point depressant -- -- 0.40
 -- --
 Antioxidant -- -- 1.00
 -- --
 Balance of additive system -- -- -- --
 5.79
 Neutral Ca alkylsalicylate (64 TBN) -- -- -- --
 2.00
 Overbased Ca phenate (190 TBN) -- -- 1.55
 -- --
 Overbased Ca sulphonate (300 TBN) -- -- -- --
 0.85
 Viscosity measured kV @ 1000.degree. C. 13.55 13.53
 13.54 13.46 13.19
 Nitration Test oxidation (relative) 1.00 1.11
 0.90 1.00 0.62
 nitration (relative) 1.00 1.04
 1.16 1.00 0.77
 viscosity increase (relative) 1.00 1.62
 1.24 1.00 1.00
 Total medium + low TBN detergents vol %, by a.i. N/A --
 1.47 N/A 1.36
 Total high TBN detergents vol %, by a.i. N/A --
 0.62 N/A 0.47
 High:medium + low TBN detergents ratio, vol % N/A --
 0.42 N/A 0.35
 Notes: (1) B* is a repeat blend of B using same components and exact same
 formulation.