Patent Application
20100173808
Traditionally the protection of metal parts of ingnition engines has been provided by a combination of neutral to overbased detergents together with zinc dithiophosphate (ZnDTP).
Exhaust gas after treatment systems for vehicles are now required in order to comply with Clean Air Legislation, i.e. new Japanese or European legislation. The efficiency of these systems can be impaired by lubricant ash—originating from metal, sulfur and phosphorus containing additives. Therefore the amount of ash containing detergents and phosphorus and ash containing ZnDTP has been reduced in recently formulated oils in order to comply with current and impending specifications. This can result in diminished corrosion protection of metal parts in the engine.
U.S. Pat. No. 4,734,209 discloses copper passivators for functional fluids.
U.S. Pat. Nos. 5,171,463 and 5,032,300 teach benzotriazole based copper passivators.
U.S. Pat. No. 6,410,490 teaches benzotriazole additives for lubricants.
U.S. Pat. Nos. 6,008,165 and 6,010,986 teach borates as a means to control lead corrosion.
Surprisingly, it has been found that a combination of a certain metal deactivator, a borate ester and optionally an amine phosphate when added to a lubricant will maintain a high level of protection of bearings and other parts of an engine.
The invention allows for the formulation of engine lubricants that can protect copper, lead, iron and zinc from corrosion for the life of the lubricant. In the case of engine oils, in spite of the reduction in concentration of traditional protectants—overbased detergent and ZnDTP.
Overbased detergents are known to those skilled in the art and are for example phenates, sulphonates or salicylates. ZnDTP and detergent content are controlled by SAPS restrictions (sulfated ash, phosphorus and sulfur). ZnDTP content is controlled mainly by the maximum limits set on the % P content in various engine oil specifications. ILSAC and API have stepped down the P content for passenger car oils as follows:
The next category, GF-5 (scheduled for 2009) calls for controlling P by using a catalytic converter poisoning test. If no test is available, the P limit will go down further to either 0.06 or 0.05% P max.
In Europe, ACEA 2004 specifications for gasoline and diesel engines with aftertreatment devices also required reductions in phosphorus content.
The new ACEA E6 heavy duty diesel engine specification has a 0.08% max limit for phosphorus.
Total ash limits are also to be lowered. This will impact detergent and ZnDTP content.
Sulfur limits are also part of the equation as they limit the contribution that can come from ZnDTP and sulfonate detergents (also sulfurized phenate detergents).
Reduction of these materials leads to a reduction in ability to protect the lubricant against copper and lead corrosion in engines. Further, fuel economy requirements necessitate increased use of friction modifiers such as glycerol monoleate and certain molybdenum compounds. These materials may be corrosive towards either copper or lead or both. U.S. Pat. No. 2,898,299 teaches the aggressiveness of glycerol monoleate towards copper-lead bearing alloys. U.S. Pat. No. 5,631,213, EP 1,382,659 and D. T. Jayne, J. R. Shanklin, and C. F. Stachew, “Controlling the Corrosion of Copper Alloys in Engine Oil Formulations: Antiwear, Friction Modifier, Dispersant Synergy”, SAE Paper 2002-01-2767, teach the corrosiveness of certain molybdenum compounds towards copper and copper alloys. Additionally, certain industrial oils are aggressive to zinc.
Disclosed is a lubricant composition comprising
a) lubricant,
b) a triazole metal deactivator,
c) a borate ester and optionally
d) an amine phosphate.
Also disclosed is a method for controlling the corrosion of lead, copper, iron and zinc in a lubricant,
which method comprises incorporating into a lubricant
b) a triazole metal deactivator,
c) a borate ester and optionally
d) an amine phosphate.
The engine oils of this invention utilize either natural (e.g. —vegetable), mineral or synthetic base fluids. Most commonly, API Group I, II and III, mineral and synthetic oils, Group IV, poly-α-olefins, Group V, e.g. —esters are utilized. Synthetic oils may also be derived from Fischer-Tropsch gas-to-liquid synthetic procedures. These products may often be hydroisomerized. Mixtures of two or more of the above base fluids may be used. The finished fluids are used for example in internal combustion engines, for example motor vehicles fitted for example with engines of the Otto, Diesel, two-stroke Wankel or orbital type.
The present engine oils contain for example less than about 1.1% by weight ash. For example, the present engine oils contain less than about 0.9% ash or less than about 0.8% ash. The present engine oils contain less than about 0.1% by weight phosphorus. For example, the present engine oils contain less than about 0.08, less than about 0.07, or less than about 0.06% by weight phosphorus. The present engine oils have for example less than about 0.5% sulfur, for instance less than about 0.4% by weight sulfur.
Ash is determined by the sulfated ashing technique, ASTM D 874.
Industrial lubricants are for example polyalkylene glycols and are employed for example in windmills.
The present triazole metal deactivators are of the 1,2,4-triazole class or the benzotriazole class.
Metal deactivators of the 1,2,4-triazole class are disclosed for example in U.S. Pat. No. 4,734,209, the disclosure of which is hereby incorporated by reference.
The 1,2,4-triazole metal deactivators are for example of the formula (I)
where
R1 and R2 are the same or different and are C1-C20alkyl, C3-C20alkenyl, C5-C12cycloalkyl, C7-C13aralkyl or C6-C10aryl, or R1 and R2, together with the nitrogen atom to which they are each attached may form a 5-, 6- or 7-membered heterocylic ring, or R1 and R2 are a group of formula
R3X[(—R4—)O]n(—R4)—
where
X is O, S or N,
R3 is hydrogen or C1-C20alkyl,
R4 is C1-C12alkylene,
n is 0 or an integer from 1 to 6, or one of R1 and R2 is a group of formula
or R2 is a group of formula (II) and R1 is a group of formula
—[R4]n—N(R5)-A-[N(R5)2]m
where
m is 0 or 1 and, when m is zero, A is a group of formula (II) and, when m is 1, A is alkylene or C6-C10 arylene and R5 is a group of formula (II).
R4 is for example a C1-C6alkylene group, for instance a C2-C3alkylene.
n is for instance 0, 1, 3, 4, 5 or 6.
Specific compounds of present formula (I) include:
The present compound of formula (I) is for example 1-(di-isooctylaminomethyl) triazole, that is 1-(di-isooctylaminomethyl)-1,2,4-triazole, or is 1-(di-(2-ethylhexyl)aminomethyl)1,2,4-triazole.
The benzotriazole metal deactivators are for example those disclosed in U.S. Pat. Nos. 5,032,300 and 5,171,463, the disclosures of which are hereby incorporated by reference.
The benzotriazole metal deactivators are for example of the formula (III)
where
R6 is C1-C12alkyl,
R7 is C1-C12alkyl, C1-C12alkyl interrupted by one or more O atoms or is C5-C12cycloalkyl and
R8 and R9 are hydrogen or methyl.
Specific examples of compounds of formula (III) include:
The present compound of formula (III) is for example 1-(2-methoxyprop-2-yl)tolyltriazole, 1-(1-cyclohexyloxypropyl)tolyltriazole, 1-(1-cyclohexyloxyheptyl)tolyltriazole or 1-(1-cyclohexyloxybutyl)tolyltriazole.
(1-(2-methoxyprop-2-yl)tolyltriazole is
1-(1-cyclohexyloxyheptyl)tolyltriazole is
The benzotriazole metal deactivators are for example those as disclosed in U.S. Pat. No. 6,410,490, the disclosure of which is hereby incorporated by reference.
The benzotriazole metal deactivators are for example of the formula (IV)
wherein
R10 is hydrogen or C1-C12alkyl, and
R11 and R12 are the same or different and are C1-C20alkyl, C3-C20alkenyl, C3-C12cycloalkyl, C7-C13aralkyl or C6-C10aryl, or R11 and R12, together with the nitrogen atom to which they are each attached may form a 5-, 6- or 7-membered heterocylic ring, or R11 and R12 are a group of formula
R3X[(—R4—)O]n(—R4)—
where
X is S or N,
R3 is hydrogen or C1-C20alkyl,
R4 is C1-C12alkylene,
n is 0 or an integer from 1 to 6,
or one of R11 and R12 is a group of formula
or R12 is a group of formula (II) and R11 is a group of formula
—[R4]n—N(R5)-A-[N(R5)2]m
where
m is 0 or 1 and, when m is zero, A is a group of formula (II) and, when m is 1, A is alkylene or C6-C10arylene and R5 is a group of formula (II).
R4 is for example a C1-C6alkylene group, for instance a C2-C3alkylene.
n is for instance 0, 1, 2, 3, 4, 5 or 6.
The benzotriazole metal deactivators of formula (IV) are prepared by known methods, such as reacting a benzotriazole with formaldehyde and an amine, as described for example in U.S. Pat. No. 4,701,273. Preferably, R10 is hydrogen or methyl. Preferably, the metal deactivator is 1-[bis(2-ethylhexyl)aminomethyl-4-methylbenzotriazole.
The triazole metal deactivator is present from about 0.01 to about 0.30 percent, based on the weight of the lubricant. For instance, the triazole is present from about 0.02 to about 0.2 or from about 0.03 to about 0.1 weight percent, based on the weight of the lubricant.
The borate ester compounds are for example those disclosed in U.S. Pat. Nos. 6,008,165 and 6,010,986, the disclosures of which are hereby incorporated by reference.
The borate esters are for example of the formula
(R15O)3B or
where
R15 is independently hydrogen, C1-C20alkyl, C3-C20alkenyl, C5-C12cycloalkyl, C7-C13aralkyl or C6-C10aryl, with the proviso that at least one R15 group is not hydrogen.
R15 is for example a C4-C16 alkyl group.
For instance, all three R15 groups are alkyl groups.
For instance, the borate ester is of the formula (R15O)3B.
The borate esters are for example
triethyl borate, tripropyl borate, triisopropyle borate, tributyl borate, tripentyl borate, trihexyl borate, tricyclohexyl borate, trioctyl borate, triisooctyl borate, tridecyl borate, tri(C8C10) borate, tri (C12-C15) borate and oleyl borate.
The borate ester is present from about 0.02 to about 1.0 percent by weight based on the weight of the lubricant. For instance, the borate ester is present from about 0.03 to about 0.9, from about 0.04 to about 0.7, or from about 0.05 to about 0.5 percent by weight, based on the weight of the lubricant.
Alkyl is straight or branched chain and is for example methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl or n-eicosyl.
Alkenyl is straight or branched chain and is for example prop-2-enyl, but-2-enyl, 2-methyl-prop-2-enyl, pent-2-enyl, hexa-2,4-dienyl, dec-10-enyl or eicos-2-enyl.
Cylcoalkyl is for example cyclopentyl, cyclohexyl, cyclooctyl, cyclodecyl, adamantyl or cyclododecyl.
Aralkyl is for example benzyl, 2-phenylethyl, benzhydryl or naphthylmethyl.
Aryl is for example phenyl or naphthyl.
When R1 and R2 together with the nitrogen atom to which they are attached form a heterocyclic group, the heterocyclic group is for example a morpholine, pyrrolidine, piperidine or a perhydroazepine ring.
Alkylene moieties include for example methylene, ethylene, 1:2- or 1:3-propylene, 1:4-butylene, 1:6-hexylene, 1:8-octylene, 1:10-decylene and 1:12-dodecylene.
Arylene moieties include for example phenylene and naphthylene.
Amine phosphates are for instance salts comprising specialty amines and mixed mono- and di-acid phosphates. The mono- and di-acid phosphate amines have the structural formulae:
wherein R27 is hydrogen, C1-C25 linear or branched chain alkyl which is unsubstituted or substituted by one or more C1-C6alkoxy groups, a saturated acyclic or alicyclic group, or aryl;
R28 is C1-C25 linear or branched chain alkyl which is unsubstituted or substituted by one or more C1-C6alkoxy groups, a saturated acyclic or alicyclic group, or aryl;
R29 is hydrogen, C1-C25 linear or branched chain alkyl, a saturated or unsaturated acyclic or alicyclic group, or aryl; and
R30 and R31 are, each independently of the other, C1-C25 linear or branched chain alkyl, a saturated or unsaturated acyclic or alicyclic group, or aryl.
Preferably, R27 and R28 are linear or branched C1-C12 alkyl; and R29, R30 and R31 are linear or branched C1-C18 alkyl.
The amine phosphate is for example of the formula
wherein R33 is n-hexyl, R34 is C11-C14 branched alkyl, and when x=1 then y=2; when x=2 then y=1.
The amine phosphates are present from about 0.02 to about 0.50 percent by weight, based on the weight of the lubricant. For example, the amine phosphates are present from about 0.03 to about 0.4 percent by weight, based on the weight of the lubricant.
The lubricant may further contain viscosity index improvers. Examples of viscosity index improvers are:
Polyacrylates, polymethacrylates, vinylpyrrolidone/methacrylate copolymers, polyvinylpyrrolidones, polybutenes, olefin copolymers, styrene/acrylate copolymers and polyethers.
The lubricant may further contain ashless dispersants, detergents and/or an antiwear systems, either ZnDTP or ashless phosphorus compounds or phosphorus free antiwear additives.
The antiwear additives are selected from:
1) dihydrocarbyl dithiophosphate metal salts where the metal is aluminum, lead, tin manganese, cobalt, nickel, zinc or copper, but most often zinc. The zinc salt (zinc dialkyl dithiophosphate) is represented as
where R and R′ are independently C1-C20 alkyl, C3-C20 alkenyl, C5-C12 cycloalkyl, C7-C13 aralkyl or C6-C10 aryl, for example R and R′ are independently C1-C12 alkyl,
and
2) sulfur- and/or phosphorus- and/or halogen-containing compounds, such as sulfurized olefins and vegetable oils, tritolyl phosphate, tricresyl phosphate, chlorinated paraffins, alkyl and aryl di- and trisulfides, amine salts of mono- and dialkyl phosphates, amine salts of methylphosphonic acid, diethanolaminomethyltolyltriazole, di(2-ethylhexyl)-aminomethyltolyltriazole, derivatives of 2,5-dimercapto-1,3,4-thiadiazole, ethyl ((bisisopropyloxyphosphinothioyl)thio)propionate, triphenyl thiophosphate (triphenyl phosphorothioate), tris(alkylphenyl) phosphorothioates and mixtures thereof (for example tris(isononylphenyl) phosphorothioate), diphenylmonononylphenyl phosphorothioate, isobutylphenyl diphenyl phosphorothioate, the dodecylamine salt of 3-hydroxy-1,3-thiaphosphetan 3-oxide, trithiophosphoric acid 5,5,5-tris(isooctyl 2-acetate), derivatives of 2-mercaptobenzothiazole, such as 1-(N,N-bis(2-ethylhexyl)aminomethyl)-2-mercapto-1H-1,3-benzothiazole or ethoxycarbonyl 5-octyldithiocarbamate.
The dispersants are selected from:
1) Mannich bases that are condensation reaction products of a high molecular weight phenol, an alkylene polyamine and an aldehyde such as formaldehyde,
2) succinic-based dispersants that are reaction products of a olefin polymer and succinic acylating agent (acid, anhydride, ester or halide) further reacted with an organic hydroxy compound and/or an amine,
Ashless (metal-free) polymeric materials that usually contain an oil soluble high molecular weight backbone linked to a polar functional group that associates with particles to be dispersed are typically used as dispersants. Commonly used hydrocarbon backbone materials are olefin polymers and copolymers, i.e. —ethylene, propylene, butylene, isobutylene, styrene; there may or may not be further functional groups incorporated into the backbone of the polymer. Polar materials such as amines, alcohols, amides or esters are attached to the backbone via a bridge.
The detergents are selected from:
Calcium, magnesium, barium, sodium or lithium salts of organic acids, for example sulphonates, alkylphenates, sulfurised alkyl phenates, carboxylates, salicylates, phosphonates, thiophosphonates and phosphinates. The salts may be neutral or may be overbased by for example metal hydroxides or carbonates.
Also subject of the present invention is a lubricant additive composition, which composition comprises
b) a triazole metal deactivator,
c) a borate ester and
a dispersant.
Dispersants are those known for use in lubricants, for example polyisobutenylsuccinimides, polybutenylphosphonic acid derivatives or copolymers of vinyl acetate and fumaric acid esters.
For example, the dispersants are amine or alcohol products of hydrocarbyl-substituted succinic acylating agents. The dispersants are in particular polyisobutenylsuccinimides. For example, dispersants as disclosed in U.S. Pat. Nos. 5,112,507, 6,440,905 and 5,587,432 and references cited therein. These disclosures are incorporated herein by reference.
The weight:weight ratio of triazole metal deactivator to borate ester is from about 1:10 to about 10:1, for example from about 1:7 to about 7:1, from about 1:5 to about 5:1, from about 1:3 to about 3:1. For example the weight:weight ratio of triazole metal deactivator to borate ester is from about 1:2 to about 1:5 or from about 1:2 to about 1:4.
The weight amount of dispersant employed in the additive composition is from about 1% to about 50%, based on the total weight of triazole metal deactivator and borate ester. For instance, the weight amount of dispersant in the additive composition is from about 2% to about 30%, from about 3% to about 25% or from about 4% to about 20%, based on the total weight of triazole metal deactivator and borate ester.
For instance, a typical additive composition is about 5% dispersant, about 25% triazole metal deactivator and about 70% borate ester, each by weight.
For the corrosion bench test see: C. M. Cusano and J. C. Wang, Corrosion of Copper and Lead Containing Materials by Diesel Lubricants, J. Soc. Tribologists and Lubrication Engineers, 51(1) 89-95, 1994; and ASTM D 5968 and D 6594. This test is commonly used in engine oil specifications to validate a lubricants' ability to protect against copper and lead corrosion.
The following formulations are prepared in a 5W-30 SM type passenger car motor oil containing 0.05% phosphorus and friction modifiers in an API Group II base oil. Formulations are weight percent based on the total formulation.
The borate ester is (R15O)3B where R15 is a mixed C5-C13 alkyl. The borate is employed at 60 ppm and 120 ppm B treat level.
The triazole metal deactivator A is 1-(di-(2-ethylhexyl)aminomethyl)-1,2,4-triazole. The triazole metal deactivator B is methyl-1-(di-(2-ethylhexyl)aminomethyl)-benzotriazole.
High Temperature Corrosion Bench Test is performed according to ASTM D 6594, 168 hours @ 135° C. Corrosion results are as follows in ppm increase by weight.
An additive mixture is prepared by blending together 5% by weight a succinimde dispersant, HITEC 646, 25% by weight 1-(di-(2-ethylhexyl)aminomethyl)-1,2,4-triazole and 70% by weight the borate ester (R15O)3B where R15 is a mixed C5-C13 alkyl.
The mixture is incorporated into a polyalkylene glycol industrial oil.
The following results for zinc corrosion in polyalkylene glycol (PAG) are below. Corrosion results are in ppm Zn obtained after 30 hours at 125° C.
This application is a continuation of application Ser. No. 12/012,590, filed Feb. 4, 2008, pending, which claims benefit of U.S. provisional application No. 60/899,946, filed Feb. 7, 2007, the contents of which applications are incorporated by reference. The present invention is aimed at controlling the corrosion of lead, copper, iron and zinc in lubricants. Lubricants are for example low ash, low phosphorus engine oils (engine fluids) or industrial oils.
| Number | Date | Country | |
|---|---|---|---|
| 60899946 | Feb 2007 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12012590 | Feb 2008 | US |
| Child | 12723879 | US |
