JP2008505995A - Lubricating oil composition - Google Patents

Abstract

A lubricating oil composition suitable for lubricating an internal combustion engine and having advantageous TBN (total base number) retention is provided.
A base oil, and (A) one or more cleaning agents selected from a phenolate cleaning agent, a salicylate cleaning agent, and a sulfonate cleaning agent, wherein the one or more cleaning agents are each independently As measured by ISO 3771, 30-350 mg. The detergent having a TBN in the range of KOH / g, and (B) one or more antioxidants selected from the group consisting of amine-based antioxidants and / or phenol-based antioxidants of 3.5% by weight or more (With respect to the total weight of the lubricating oil composition), a lubricating oil for internal combustion engines having a sulfide ash content of 0.9% by weight or less and a phosphorus content in the range of 0.04 to 0.1% by weight Composition.
[Selection figure] None

Description

  The present invention relates to a lubricating oil composition, and particularly to a lubricating oil composition suitable for lubricating an internal combustion engine.

  Total Base Number (TBN) is a measure of how well a lubricating oil composition can neutralize combustion / oxidation acidic by-products and neutralizes all basic components present in a 1 g sample of lubricating oil. It is defined as the amount of acid required for the reaction and expressed in terms of equivalent number of potassium hydroxide (test methods include, for example, ISO 3771, ASTM D-2896, and ASTM D-4739).

In lubricating oil compositions, high TBN is desired to control corrosive engine wear due to acidic by-products of combustion / oxidation. Cleaning additives in the lubricating oil composition are the primary source of alkalinity (TBN) and help control, for example, top ring deposition and inner diameter polishing.
Thus, metal-based cleaning agents are a major source of crankcase lubricating oil compositions.

  Considering that the concentration of sulfide ash, sulfur and phosphorus in the lubricating oil composition adversely affects the exhaust aftertreatment device of automobiles, a lubricating oil composition having a low concentration of sulfide ash, sulfur and / or phosphorus (ie, so-called There is a tendency towards low SAPS lubricating oil compositions).

The concentration of phosphorus can be reduced by reducing the amount of zinc dithiophosphate generally present as an antiwear additive in the lubricating oil composition.
The sulfur level in the lubricating oil composition can be reduced by using a low sulfur level base oil and reducing the amount of sulfur-containing additive used in the composition.

  The sulfide ash is the total weight percent of residue remaining after carbonizing the lubricating oil composition, treating the residue with sulfuric acid, and then heating to a constant weight. The sulfide ash content in the lubricating oil composition is related to the total metal content in the composition. The sulfide ash content can be conveniently measured according to ASTM D874.

  The main source of sulfide ash in lubricating oil compositions is the metal cleaning additive and zinc dithiophosphate antiwear additive commonly used in the composition.

  Therefore, in current low SAPS lubricating oil compositions, the level of sulfide ash, and hence the level of detergent, is low. As a result, the starting TBN of the low SAPS lubricating oil composition (ie, the TBN of the new unused lubricating oil composition) is likely to be lower than the lubricating oil composition containing a high concentration of sulfided ash, sulfur and / or phosphorus. .

  Thus, low SAPS lubricating oil compositions with low starting TBN are of increasing importance to TBN retention (ie, the ability to maintain advantageous TBN levels throughout the life of the lubricating oil composition).

US 2004/0102335 A1 describes a lubricating oil composition comprising an additive formulation having at least one sulfonate, saligenin (salicylic alcohol) and a salixarate detergent.
However, as is clear from the examples of US 2004/0102335 A1, this lubricating oil composition uses a high TBN detergent.

In this regard, all examples of US 2004/0102335 A1 use a high TBN calcium sulfonate detergent as the TBN enhancer.
Moreover, US 2004/0102335 A1 relates to the development of lubricating oil compositions with improved wear characteristics and is not directed to the problem of TBN retention in low SAPS lubricating oil compositions with low starting TBN.

EP-A-1167497 has a sulfur content of 0.01-0.3% by weight and a phosphorus content of 0.01-0. Disclosed is a lubricating oil composition that is said to exhibit good high temperature detergency, with a sulphided ash content in the range of 0.1 to 1% by weight. This composition is
a) Major amount of mineral base oil having a sulfur content of 0.1% by weight or less,
b) an ash-free dispersant containing alkenyl- or alkyl-succinimide or a derivative thereof in an amount of 0.01 to 0.3% by weight in terms of nitrogen atom content,
c) TBN of 10 to 350 mg. An organic acid metal salt selected from the group consisting of a non-sulfurized alkali metal or alkaline earth metal salt of salicylic acid of KOH / g and a non-sulfurized alkali metal or alkaline earth metal salt of an alkylphenol derivative having a Mannich base structure 0.1 to 1% by weight of metal-containing detergent in terms of sulfide ash content,
d) 0.01 to 0.1% by weight of zinc dialkyldithiophosphate in terms of phosphorus content, and e) 0.01 to 5% by weight of an antioxidant selected from the group consisting of phenolic compounds and amine compounds. ,
contains.
All examples of EP-A-1167497 use a mixture of 0.7% by weight of an amine antioxidant and 0.7% by weight of a phenolic antioxidant.

  However, EP-A-11167497 is not a method for the problem of achieving good TBN retention for compositions with low sulfide ash, sulfur and / or phosphorus concentrations, especially in the VW T4 test (PV 1449). In this regard, there is no teaching in EP-A-1167497 suggesting how to achieve good TBN retention, especially in the VW T4 test (PV 1449).

EP-A-1104800 includes
a) Major amount of viscosity-lubricating base oil,
b) 0.1-1% by weight of metal-containing cleaning agent in terms of sulfide ash content,
c) Boron-containing alkenyl- or alkyl-succinimide in an amount of 1.0 to 15% by weight in terms of active ingredient,
d) 0.1 to 0.1% by weight of zinc dialkyldithiophosphate in terms of phosphorus content,
e) 0.1 to 5% by weight of antioxidant in terms of active ingredient, and f) 0.1 to 5% by weight of dithiocarbamate without ash in terms of active ingredient,
A lubricating oil composition for an internal combustion engine is described.

  US 2003/0148900 A1 presents a lubricating oil composition for natural gas engines comprising a minor amount of one or more specific hindered phenols and a major amount of a group II, group III and group IV base oil leets. Disclosure.

  US 2003/0148900 A1 shows that increasing amounts of antioxidants can have a detrimental effect on biston deposition control. US 2003/0148900 A1 is therefore directed to a method for extending the oxidation life of a lubricating base oil without increasing the amount of antioxidant.

However, US 2003/0148900 A1 is not related to the problem of TBN retention in low SAPS lubricating oil compositions with low starting TBN.
WO-A-03 / 083020 describes a method for operating an internal combustion engine in which a nitrogen-containing cleaning composition is introduced into the internal combustion chamber during engine operation.

This detergent composition is
(A) a reaction product of a hydrocarbyl-substituted acrylating agent and an amine,
(B) a hydrocarbyl-substituted amine,
(C) Mannich reaction product of hydrocarbyl-substituted hydroxy-containing aromatic compound, aldehyde and amine,
(D) 1 unit of a hydroxy-containing hydrocarbyl compound and 2 units or more of butylene oxide are reacted to form a polyether intermediate, which is reacted with an amine or acrylonitrile, and a reaction product of the polyether intermediate and acrylonitrile is obtained. A high molecular weight polyetheramine produced by amination by hydrogenation, or (E) a mixture thereof,
Containing.

  U.S. Pat. No. 5,595,964 describes an internal combustion engine fueled with natural gas containing a lubricating oil, an anti-oxidant, an anti-nitriding agent and preferably an epoxide boride product of about 0.1% by weight or more. A method of lubricating the internal combustion engine for supplying a composition is described. The amount of the composition supplied is substantially free of metal, and the amount of antioxidant and nitriding agent is sufficient to reduce the amount of varnish formation in the internal combustion engine.

It is stated that the total amount of antioxidant used in this lubricating oil composition is 1.8% by weight or more, preferably 2% by weight.
The lubricating oil composition of US-A-5595964 states that it contains less than 1% sulfide ash as measured by ASTM D874.

  US-A-5595964 states that the phosphorus level of the lubricating oil composition is preferably less than 0.03%, more preferably less than 0.005%.

  US-A-5595964 relates to the reduction of a varnish formulation in a natural gas fueled internal combustion engine by the presence of an antioxidant as well as an anti-nitriding agent in the lubricating oil composition.

  US-A-5595964 does not identify or suggest the problem of poor TBN retention in lubricating oil compositions with low sulfide ash, sulfur and / or phosphorus concentrations, particularly low SAPS lubricating oil compositions with low starting TBN. US-A-5595964 discloses how to achieve good TBN retention in such lubricating oil compositions, particularly how to pass the VW T4 test (PV 1449). Absent.

Therefore, to develop a low sulfide ash, sulfur and / or phosphorus concentration lubricating oil composition with good TBN retention, especially a low SAPS lubricating oil composition with low starting TBN and good TBN retention Is desirable.
US 2004/0102335 A1 EP-A-1167497 EP-A-1104800 US 2003/0148900 A1 WO-A-03 / 083020 US-A-5595964 EP-A-776959 EP-A-668342 WO-A-97 / 21788 WO-00 / 14188 WO-00 / 14187 WO-00 / 14183 WO-00 / 14179 WO-00 / 08115 WO-99 / 41332 EP-1029029 WO-01 / 18156 WO-01 / 57166 WO-A-98 / 26030 Japanese patent no. 13677796 Japanese patent no. 1667140 Japanese patent no. 1302811 Japanese patent no. 1743435 Japanese patent no. 954077 Japanese patent no. 1031507 Japanese patent no. 1468752 Japanese patent no. 1764494 Japanese patent no. 1751082 Japanese patent no. 1195542 Japanese patent no. 1264056

  Lubricating oil compositions that have good TBN retention, particularly in the VW T4 test (PV 1449), and more particularly the end value (end) of the test (VW T4 test (PV 1449)) TBN value as measured by ISO 3771 5.0 mg. It is desirable to develop a lubricating oil composition having a KOH / g or higher.

  In the present invention, a lubricating oil composition suitable for lubricating an internal combustion engine and having advantageous TBN retention has been unexpectedly found.

Therefore, the present invention
Base oil,
(A) One or more cleaning agents selected from a phenolate cleaning agent, a salicylate cleaning agent and a sulfonate cleaning agent, each of the one or more cleaning agents being independently measured by ISO 3771, 30 -350 mg. The detergent having a TBN (total base number) in the range of KOH / g;
(B) 3.5 wt% or more (based on the total weight of the lubricating oil composition) of one or more antioxidants selected from the group consisting of amine antioxidants and / or phenolic antioxidants;
And a lubricating oil composition for an internal combustion engine having a sulfur ash content of 0.9% by weight or less and a phosphorus content in the range of 0.04 to 0.1% by weight.

In a preferred embodiment, the one or more antioxidants are 3.7% by weight or more, more preferably 3.9% by weight or more, most preferably 4.0% by weight, based on the total weight of the lubricating oil composition. Present in the above amount.
The lubricating oil composition of the present invention may contain one or more amine antioxidants.

  Examples of amine antioxidants that can be conveniently used include alkylated diphenylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine and alkylated α-naphthylamine.

  Preferred amine antioxidants include p, p′-dioctyl-diphenylamine, p, p′-di-α-methylbenzyl-diphenylamine and Np-butylphenyl-Np′-octylphenylamine. Dialkyldiphenylamines; monoalkyldiphenylamines such as mono-t-butyldiphenylamine and mono-octyldiphenylamine; bis (such as di- (2,4-diethylphenyl) amine and di (2-ethyl-4-nonylphenyl) amine Dialkylphenyl) amine; alkylphenyl-1-naphthylamines such as octylphenyl-1-naphthylamine and nt-dodecylphenyl-1-naphthylamine; 1-naphthylamine; phenyl-1-naphthylamine, phenyl-2-naphthylamine, N— Aryl naphthylamines such as xylphenyl-2-naphthylamine and N-octylphenyl-2-naphthylamine; N, N′-diisopropyl-p-phenylenediamine and N, N′-diphenyl-p-phenylenediamine; and phenothiazine and 3, And phenothiazines such as 7-dioctylphenothiazine.

Preferred amine-based antioxidants include the following trade names: “Sonoflex OD-3” (from Seiko Kagaku Co.), “Irganox L-57” (from Ciba Specialty Chemicals Co.), and phenothiazine (from Hodogaga K.). ).
The lubricating oil composition of the present invention may contain one or more phenolic antioxidants.

  Examples of phenolic antioxidants that can be conveniently used include C5-C9 branched alkyl esters of 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-benzenepropionic acid; 2-t-butylphenol; 2-t-butyl-4-methylphenol; 2-t-butyl-5-methylphenol; 2,4-di-t-butylphenol; 2,4-dimethyl-6-t-butylphenol; 2-t-butyl- 4-methoxyphenol; 3-tert-butyl-4-methoxyphenol; 2,5-di-tert-butylhydroquinone; 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-methyl 2,6-di-t-butyl-4-alkylphenols such as phenol and 2,6-di-t-butyl-4-ethylphenol; 2,6-di-t-butyl- 2,6-di-tert-butyl-4-alkoxyphenol, such as methoxyphenol and 2,6-di-tert-butyl-4-ethoxyphenol; 3,5-di-tert-butyl-4-hydroxybenzyl Mercaptooctyl acetate; n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, n-butyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) Alkyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate such as propionate and 2'-ethylhexyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate 2,6-di-t-butyl-α-dimethylamino-p-cresol; 2,2′-methylenebis (4-methyl-6-t-butylphenol); Enol) and 2,2′-methylenebis (4-alkyl-6-tert-butylphenol) such as 2,2′-methylenebis (4-ethyl-6-tert-butylphenol); 4,4′-butylidenebis (3- Methyl-6-tert-butylphenol), 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert-butylphenol), 2,2- ( Di-p-hydroxyphenyl) propane, 2,2-bis (3,5-di-t-butyl-4-hydroxyphenyl) propane, 4,4′-cyclohexylidenebis (2,6-t-butylphenol) Hexamethylene glycol bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol bis [3- (3-t-butyl 4-hydroxy-5-methylphenyl) propionate], 2,2′-thio- [diethyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 3,9-bis {1 , 1-Dimethyl-2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} 2,4,8,10-tetraoxaspiro [5,5] undecane, 4 Bisphenols such as 2,4′-thiobis (3-methyl-6-tert-butylphenol) and 2,2′-thiobis (4,6-di-tert-butylresorcinol); tetrakis [methylene-3- (3,5 -Di-t-butyl-4-hydroxyphenyl) propionate] methane, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1, , 5-Trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, bis- [3,3′-bis (4′-hydroxy-3′-t-) Butylphenyl) butyric acid] glycol ester, 2- (3 ′, 5′-di-tert-butyl-4-hydroxyphenyl) methyl-4- (2 ″, 4 ″ -di-tert-butyl-3 ″ -hydroxyphenyl) ) Polyphenols such as methyl-6-tert-butylphenol and 2,6-bis (2'-hydroxy-3'-tert-butyl-5'-methylbenzyl) -4-methylphenol; and pt-butylphenol- Examples include formaldehyde condensates and pt-butylphenol-acetaldehyde condensates.

  Preferred phenolic antioxidants include the following trade names: “Irganox L-135” (from Ciba Specialty Chemicals Co.), “Antejii DBH” (from Kawaguchi Chikaku Co.), “Yoshinox SSy. ”,“ Antage W-400 ”(from Kawaguchi Kagaku Co.),“ Antage W-500 ”(from Kawaguchi Kagaku Co.),“ Antage W-300 ”(from Kawaguchi Kon“ H ”,“ Kagawagu Ion ”) Shell Japan Co.), Shell Japan Co. Bisphenol A, “Irganox L109” (from Ciba Specialty Chemicals Co.), “Tominox 917” (from Yoshitoi Seiyaku Co.), “Irganox L115” (from Ciba Spec. ), “Antage RC” (from Kawaguchi Kagaku Co.), “Irganox L101” (from Ciba Specialty Chemicals Co.), “Yoshinox 930” (from Yoshitoi Co.) Is mentioned.

The lubricating oil composition of the present invention may contain a mixture of one or more phenolic antioxidants and one or more amine antioxidants.
The cleaning agent that can be used in the present invention includes one or more cleaning agents selected from salicylate cleaning agents, phenolate cleaning agents, and sulfonate cleaning agents.

  In the lubricating oil composition of the present invention, alkali metal and alkaline earth metal salicylates, phenolates and sulfonate detergents are preferred. Calcium and magnesium salicylates, phenolates and sulfonates are particularly preferred detergents.

  In a preferred embodiment, the lubricating oil composition of the present invention comprises (i) one or more salicylate detergents and / or (ii) a mixture of one or more phenolate detergents and one or more sulfonate detergents. May be contained.

However, since the metal organic and inorganic base salts used as cleaning agents contribute to the sulfide ash content of the lubricating oil composition, in preferred embodiments of the present invention, the amount of such cleaning additives is minimal. It is the limit.
Salicylate detergents are particularly preferred to maintain low sulfur levels.
Thus, in preferred and embodiments, the lubricating oil composition of the present invention may contain one or more salicylate detergents.

  The total sulfide ash content of the lubricating oil composition of the present invention is 0.9% by weight or less, preferably 0.8% by weight or less, more preferably 0.75% by weight or less, based on the total weight of the lubricating oil composition. Most preferably to maintain below 0.7% by weight, the one or more cleaning agents (A) are preferably 0.05-12.5% by weight, more preferably based on the total weight of the lubricating oil composition. Is used in an amount ranging from 1.0 to 9.0 wt%, most preferably from 2.0 to 5.0 wt%.

  Further, the one or more cleaning agents have a TBN (total base number) of 30 to 350 mg. KOH / g, more preferably 50 to 300 mg. The range is preferably KOH / g.

  That is, when one or more cleaning agents selected from phenolate cleaning agents, salicylate cleaning agents and sulfonate cleaning agents are present in the lubricating oil composition of the present invention, each of these cleaning agents is measured according to ISO 3771. 30-350 mg. KOH / g, more preferably 50 to 300 mg. It has a TBN (total base number) in the range of KOH / g.

  The amount of the base oil incorporated into the lubricating oil composition of the present invention is preferably in the range of 60 to 92% by weight, more preferably 75 to 90% by weight, most preferably relative to the total weight of the lubricating oil composition. Present in an amount ranging from 75 to 88% by weight.

There is no special restriction | limiting about the base oil used by this invention, Various well-known mineral oil and synthetic lubricating oil can be used conveniently.
Mineral oils include liquid petroleum and paraffinic, naphthenic or paraffin / naphthene mixed solvent-treated or acid-treated mineral lubricating oils (which may be further refined by hydrofinishing and / or dewaxing).

Naphthenic base oils have a low viscosity index (VI) (generally 40-80) and a low pour point. Such base oils are produced from feedstocks rich in naphthenes and low wax content, primarily used in lubricating oils where color and stability are important first, followed by VI and oxidation stability. Is done.
Paraffinic base oils have a high VI (generally> 95) and a high pour point. This base oil is manufactured from paraffin-rich feedstocks and is used in lubricating oils where VI and oxidative stability are important.

  Fischer-Tropsch derived base oils such as EP-A-776959, EP-A-668342, WO-A-97 / 21788, WO-00 / 14188, WO-00 / 14187 are used as the base oil of the lubricating oil composition of the present invention. , WO-00 / 14183, WO-00 / 14179, WO-00 / 08115, WO-99 / 41332, EP-1029029, WO-01 / 18156 and WO-01 / 57166. Can be used conveniently.

Depending on the synthesis method, the molecule can be made from a material with a simpler structure, or the molecular structure can be modified to give the required precise properties.
Synthetic lubricating oils include hydrocarbon oils such as olefin oligomers (PAO), dibasic acid esters, polyol esters and dewaxed waxy raffinates. Synthetic hydrocarbon base oils sold under the trade name “XHVI” (trademark) by companies of the Royal Dutch Shell group can be conveniently used.

The base oil is preferably composed of mineral oil and / or synthetic base oil with a saturate content as measured by ASTM D2007 of greater than 80 wt%, preferably greater than 90 wt%.
The base oil further preferably has a sulfur content of less than 1.0% by weight, preferably less than 0.1% by weight, as measured by ASTM D2622, D4294, D4927 or D3120 and calculated as elemental sulfur.

The viscosity index of the base oil is preferably greater than 80, more preferably greater than 120, as measured by ASTM D2270.
Kinematic viscosity at 100 ° C. of the base oil used in the present invention is preferably in the range of 2~80mm ² / s, more preferably 3~70mm ² / s, most preferably 4~50mm ² / s.

  In a preferred embodiment, the lubricating oil composition comprises zinc dithiophosphate alone or as a antiwear agent in combination of two or more zinc dithiophosphates. The zinc dithiophosphate is selected from dialkyl-, diaryl- or alkylaryl-dithiophosphate zinc.

Zinc dithiophosphate is an additive well known in the art and has the general formula II:

Can be expressed conveniently. In the formula, R ^{2 to} R ⁵ may be the same or different and are each a primary alkyl group having 1 to 20 carbon atoms, preferably 3 to 12 carbon atoms; 3 to 20 carbon atoms, preferably 3 to 3 carbon atoms. 12 secondary alkyl groups; an aryl group; or an aryl group substituted with an alkyl group having 1 to 20, preferably 3 to 18 carbon atoms.

Zinc dithiophosphate compounds in which R ^{2 to} R ⁵ are all different from each other can be used alone or in a mixture with a zinc dithiophosphate compound in which R ^{2 to} R ⁵ are all the same.
The zinc dithiophosphate compound used in the present invention is preferably zinc dialkyldithiophosphate.

  Commercially available zinc dithiophosphates include compounds obtained under the trade names “Lz 1097” and “Lz 1395” from Lubrizol Corporation, compounds obtained under the trade names “OLOA 267” and “OLOA 269A” from Chevon Orite, and Ethyl. First zinc dithiophosphates such as the compound obtained under the trade name “HITEC 7197” from Lubrizol Corporation; compounds obtained under the trade names “Lz 677A”, “Lz 1095” and “Lz 1371” from Lubrizol Corporation; A second zinc dithiophosphate such as the compound obtained under OLOA 262 ”and the compound obtained under the trade name“ HITEC 7169 ”from Ethyl; from Lubrizol Corporation Trade name "Lz 677A", "Lz 1370" and the compound obtained in "Lz 1373", and aryl type zinc dithiophosphate and the like, such as the compounds obtained under the trade designation "OLOA 260" from Chevon Oronite.

  In the lubricating oil composition of the present invention, zinc dithiophosphate (in the case of the first or second alkyl type) is generally 0.4 to 1.0% by weight, preferably 0.4%, based on the total weight of the lubricating oil composition. It is contained in a range of ˜0.9% by weight, most preferably 0.45 to 0.8% by weight.

  Accordingly, the amount of phosphorus in the lubricating oil composition of the present invention is generally 0.04 to 0.10 wt%, preferably 0.04 to 0.09 wt%, most preferably 0.045 to 0.08 wt%. % Range.

  If the phosphorus level is 0.04% by weight or less, the wear resistance may be insufficient. If the level of phosphorus is 0.1% by weight or more, phosphorus can have a detrimental effect on automobile aftertreatment devices.

  The lubricating oil composition of the present invention has a sulfide ash content of preferably 0.8% by weight or less, more preferably 0.75% by weight or less, and most preferably 0.7% by weight based on the total weight of the lubricating oil composition. % By weight or less.

  The lubricating oil composition of the present invention preferably has a sulfur content of 1.2 wt% or less, more preferably 0.8 wt% or less, most preferably 0.2 wt%, based on the total weight of the lubricating oil composition. % Or less.

Preferred compositions of the present invention have one or more of the following characteristics. % By weight is based on the total weight of the lubricating oil composition.
(I) More phosphorus than 0.04% by weight.
(Ii) More than 0.045% by weight of phosphorus.
(Iii) Phosphorus is 0.04% by weight or more.
(Iv) Phosphorus is less than 0.09% by weight.
(V) Phosphorus is 0.10% by weight or less.
(Vi) Phosphorus is 0.08% by weight or less.
(Vii) The sulfide ash content is 0.9% by weight or less.
(Viii) The sulfide ash content is 0.8% by weight or less.
(Ix) The sulfided ash content is 0.7% by weight or less.
(X) Sulfur is 1.2 wt% or less.
(Xi) Sulfur is 0.8 wt% or less.
(Xii) Sulfur is 0.2 wt% or less.

Particularly preferred compositions of the present invention are the following compositions.
(A):
Having features (i) and (iv); having features (i) and (v); having features (i) and (vi); having features (ii) and (iv); having ii) and (v); having features (ii) and (vi); having features (iii) and (iv); having features (iii) and (v); feature (iii) And having (vi);

(B):
Having features (i), (iv) and (vii); having features (i), (iv) and (viii); having features (i), (iv) and (ix); i) having (v) and (vii); having features (i), (v) and (viii); having features (i), (v) and (ix); feature (i) , (Vi) and (vii); features (i), (vi) and (viii); features (i), (vi) and (ix); features (ii), ( having iv) and (vii); having features (ii), (iv) and (viii); having features (ii), (iv) and (ix); features (ii), (v) And having (vii); having features (ii), (v) and (viii) Having characteristics (ii), (v) and (ix); having characteristics (ii), (vi) and (vii); having characteristics (ii), (vi) and (viii); Having features (ii), (vi) and (ix); having features (iii), (iv) and (vii); having features (iii), (iv) and (viii); iii) having (iv) and (ix); having features (iii), (v) and (vii); having features (iii), (v) and (viii); features (iii) , (V) and (ix); features (iii), (vi) and (vii); features (iii), (vi) and (viii); features (iii), ( having vi) and (ix);

(C):
Having features (i), (iv) and (x); having features (i), (iv) and (xi); having features (i), (iv) and (xii); i) having (v) and (x); having features (i), (v) and (xi); having features (i), (v) and (xii); features (i) , (Vi) and (x); features (i), (vi) and (xi); features (i), (vi) and (xii); features (ii), ( having iv) and (x); having features (ii), (iv) and (xi); having features (ii), (iv) and (xii); features (ii), (v) And (x); having features (ii), (v) and (xi); features (ii), (v) and having xii); having features (ii), (vi) and (x); having features (ii), (vi) and (xi); features (ii), (vi) and (xii) Having characteristics (iii), (iv) and (x); having characteristics (iii), (iv) and (xi); having characteristics (iii), (iv) and (xii) Having features (iii), (v) and (x); having features (iii), (v) and (xi); having features (iii), (v) and (xii); Having features (iii), (vi) and (x); having features (iii), (vi) and (xi); having features (iii), (vi) and (xii);

(D):
Having features (i), (iv), (vii) and (x); having features (i), (iv), (viii) and (x); features (i), (iv), ( having (ix) and (x); having features (i), (v), (vii) and (x); having features (i), (v), (viii) and (x); Having features (i), (v), (ix) and (x); having features (i), (vi), (vii) and (x); features (i), (vi), ( having viii) and (x); having features (i), (vi), (ix) and (x); having features (ii), (iv), (vii) and (x); Having features (ii), (iv), (viii) and (x); having features (ii), (iv), (ix) and (x) Having features (ii), (v), (vii) and (x); having features (ii), (v), (viii) and (x); features (ii), (v) , (Ix) and (x); having features (ii), (vi), (vii) and (x); having features (ii), (vi), (viii) and (x) Having features (ii), (vi), (ix) and (x); having features (iii), (iv), (vii) and (x); features (iii), (iv) , (Viii) and (x); having features (iii), (iv), (ix) and (x); having features (iii), (v), (vii) and (x) Having features (iii), (v), (viii) and (x); features (iii), (v , (Ix) and (x); with features (iii), (vi), (vii) and (x); with features (iii), (vi), (viii) and (x) Having characteristics (iii), (vi), (ix) and (x); having characteristics (i), (iv), (vii) and (xi); characteristics (i), (iv) , (Viii) and (xi); having features (i), (iv), (ix) and (xi); having features (i), (v), (vii) and (xi) Having features (i), (v), (viii) and (xi); having features (i), (v), (ix) and (xi); features (i), (vi) , (Vii) and (xi); with features (i), (vi), (viii) and (xi) Having features (i), (vi), (ix) and (xi); having features (ii), (iv), (vii) and (xi); features (ii), (iv) ), (Viii) and (xi); features (ii), (iv), (ix) and (xi); features (ii), (v), (vii) and (xi) Having characteristics (ii), (v), (viii) and (xi); having characteristics (ii), (v), (ix) and (xi); characteristics (ii), (vi ), (Vii) and (xi); features (ii), (vi), (viii) and (xi); features (ii), (vi), (ix) and (xi) Having characteristics (iii), (iv), (vii) and (xi); having ii), (iv), (viii) and (xi); having features (iii), (iv), (ix) and (xi); features (iii), (v), (vii) And having (xi); having features (iii), (v), (viii) and (xi); having features (iii), (v), (ix) and (xi); having (iii), (vi), (vii) and (xi); having features (iii), (vi), (viii) and (xi); features (iii), (vi), (ix) And having (xi); having features (i), (iv), (vii) and (xii); having features (i), (iv), (viii) and (xii); i) having (iv), (ix) and (xii); Having (i), (v), (vii) and (xii); having features (i), (v), (viii) and (xii); features (i), (v), (ix ) And (xii); having features (i), (vi), (vii) and (xii); having features (i), (vi), (viii) and (xii); Having (i), (vi), (ix) and (xii); having features (ii), (iv), (vii) and (xii); features (ii), (iv), (viii) ) And (xii); having features (ii), (iv), (ix) and (xii); having features (ii), (v), (vii) and (xii); Having (ii), (v), (viii) and (xii); i) having (v), (ix) and (xii); having features (ii), (vi), (vii) and (xii); features (ii), (vi), (viii) And (xii); having features (ii), (vi), (ix) and (xii); having features (iii), (iv), (vii) and (xii); having (iii), (iv), (viii) and (xii); having features (iii), (iv), (ix) and (xii); features (iii), (v), (vii) And having (xii); having features (iii), (v), (viii) and (xii); having features (iii), (v), (ix) and (xii); iii), (vi), (vii) and (xii) Intended to; wherein (iii), (vi), (viii) and (xii) those having; wherein (iii), (vi), those having a (ix) and (xii).

  The base oil composition of the present invention further includes an auxiliary antiwear agent, an auxiliary cleaning agent, a dispersant, a friction modifier, a viscosity index improver, a pour point depressant, a corrosion inhibitor, an antifoaming agent, and a seal. Other additives such as fixatives or seal compatibilizers may be included.

Supplementary antiwear agents that can be conveniently used include molybdenum-containing compounds and boron-containing compounds.
Examples of such molybdenum-containing compounds are conveniently molybdenum dithiocarbamates such as trinuclear molybdenum compounds as described in WO-A-98 / 26030, molybdenum sulfides and molybdenum dithiophosphates.

The molybdenum-containing antiwear agent may be conveniently added to the lubricating oil composition of the present invention in an amount ranging from 0.1 to 3.0% by weight, based on the total weight of the lubricating oil composition.
Boron-containing compounds that can be conveniently used include boric acid esters, borated aliphatic amines, borated epoxides, alkali metal borates (or alkali metal or alkaline earth metal mixtures) salts and borated excess base metal salts.

  The boron-containing antiwear agent may be conveniently added to the lubricating oil composition of the present invention in an amount ranging from 0.1 to 3.0% by weight, based on the total weight of the lubricating oil composition.

  The TBN value of a new unused sample of the lubricating oil composition of the present invention is preferably 5.0-12.0 mg. KOH / g, more preferably 6.0 to 11.0 mg. KOH / g, still more preferably 6.0-10.0 mg. KOH / g, most preferably 6.0-9.0 mg. It is in the range of KOH / g.

  The lubricating oil composition of the present invention may further contain a ash-free dispersant mixed and contained in an amount preferably in the range of 5 to 15% by weight with respect to the total weight of the lubricating oil composition.

  Examples of dispersants that can be used include Japanese Patent No. And polyalkenyl succinimides and polyalkenyl succinic acid esters described in JP-A Nos. 1377796, 1667140, 1302811, and 1743435. A preferred dispersant is boric succinimide.

Preferred friction modifiers that can be conveniently used are fatty acid amides, more preferably unsaturated fatty acid amides.
The total amount of friction modifier added to the lubricating oil composition of the present invention is conveniently 0.05 to 0.2% by weight based on the total weight of the lubricating oil composition.

  As a viscosity index improver that can be conveniently used in the lubricating oil composition of the present invention, Japanese Patent No. 954077, 1031037, 1468752, 1764494, 1751082, styrene-butadiene copolymer, styrene-isoprene star copolymer, polymethacrylate-based copolymer, ethylene-propylene copolymer, etc. Is mentioned. Such viscosity index improvers may conveniently be used in amounts ranging from 1 to 20% by weight, based on the total weight of the lubricating oil composition of the present invention. Similarly, a dispersion-type viscosity index improver containing a copolymerized polar monomer having a nitrogen atom and an oxygen atom in the molecule can also be used in the composition.

Japanese patent no. Polymethacrylates such as those disclosed in 1195542 and 1264056 can be conveniently used as an effective pour point depressant in the lubricating oil composition of the present invention.
In addition, compounds such as alkenyl succinic acid or its ester moiety, benzotriazole-based compounds and thiodiazole-based compounds can be conveniently used as corrosion inhibitors in the lubricating oil compositions of the present invention.

Compounds such as polysiloxane, dimethylpolycyclohexane, and polyacrylate can be conveniently used as an antifoaming agent in the lubricating oil composition of the present invention.
Compounds that can be conveniently used as a seal fixative or seal compatibilizer in the lubricating oil composition of the present invention include, for example, commercially available aromatic esters.

  The lubricating oil composition of the present invention comprises one or more cleaning agents (A), one or more antioxidants (B) selected from amine-based antioxidants and / or phenol-based antioxidants, and optionally One or more other additives normally present in lubricating oils can be conveniently prepared by mixing with mineral and / or synthetic base oils.

The lubricating oil composition of the present invention exhibits advantageous TBN retention, particularly in the VW T4 test (PV 1449).
In a preferred embodiment of the present invention, the end value of the test (VW T4 test (PV 1449) TBN value is 5.0 mg.KOH / g or more, as measured by ISO 3771.

  In a preferred embodiment of the present invention, the TBN value of a fresh new sample of the lubricating oil composition of the present invention is 5.0-12.0 mg. The end value of the test (VW T4 test (PV 1449) TBN value) is 5.0 mg.KOH / g or more.

  In another preferred embodiment of the present invention, the TBN value of a fresh new sample of the lubricating oil composition of the present invention is 6.0-11.0 mg. It is in the range of KOH / g, and the terminal value of the test (VW T4 test (PV 1449) TBN value is 6.0 mg.KOH / g or more.

  In yet another preferred embodiment of the present invention, the TBN value of a new unused sample of the lubricating oil composition of the present invention is 6.0 to 10.0 mg. It is in the range of KOH / g, and the terminal value of the test (VW T4 test (PV 1449) TBN value is 6.0 mg.KOH / g or more.

  In the present invention, the TBN change between the TBN value of a new unused sample of the lubricating oil composition of the present invention and the terminal value of the test (VW T4 test (PV 1449) TBN value) of the same lubricating oil composition (ie, ΔTBN is , Is the terminal value of the new oil TBN-test TBN) is less than 2.5 mg.KOH / g, more preferably less than 2.0 mg.KOH / g, most preferably less than 1.8 mg.KOH / g It is preferable.

In a preferred embodiment of the invention, the test (VW T4 test (PV 1449) Vk40 value (ie kinematic viscosity at 40 ° C.) is less than 200 mm ² / s (cSt).

  Thus, in a preferred embodiment of the invention, the TBN level is measured according to ISO 3771 to 5.0 mg. In order to maintain above KOH / g, there is provided a method of using the aforementioned lubricating oil composition in an internal combustion engine, particularly with respect to the VW T4 test (PV 1449).

In another embodiment of the present invention, there is provided a method for lubricating an internal combustion engine, wherein the lubricating oil composition described above is applied to the internal combustion engine.
The invention is illustrated by the following examples which are not intended to limit the scope of the invention in any way.

Formulations Table 1 shows the formulations tested.
The formulations in Table 1 contain conventional detergents, antifoaming agents, dispersants, pour point depressants, viscosity index improvers and zinc dithiophosphate additives, which are additives in the diluent oil. Present as a package.

The phenolic antioxidant used was Ciba Specialty Chemicals Co. (C7-C9 branched alkyl ester of 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-benzenepropionic acid) obtained under the trade name “Irganox L-135”.
The amine-based antioxidant used was Ciba Specialty Chemicals Co. For the product name “Irganox L-57”.

The base oil used in the formulation is a mixture of Group III base oils obtained under the trade names “XHVI-5.2” and “XHVI-8.2” from “Royal Dutch / Shell Group Companies”. All formulations listed in Table 1 are SAE 5W30 viscosity grade oils.
Table 2 shows the physical properties of the tested formulations.

1: Commercial additive packaging obtained from Lubrizol under the trade name “Lz OS183698”, each with a TBN of 30-350 mg. Contains KOH / g sulfonate detergent and phenolate detergent; dispersant; zinc dithiophosphate; and diluent oil.
2: TBN was 165 mg. KOH / g and 280 mg. Conventional additive packaging containing KOH / g mixed calcium salicylate detergent; dispersant; zinc dithiophosphate; and diluent oil.
3: TBN was 345 mg. Conventional additive packaging containing KOH / g magnesium salicylate detergent; dispersant; zinc dithiophosphate; and diluent oil.
4: TBN was 345 mg. Conventional additive packaging containing KOH / g magnesium salicylate detergent; dispersant; zinc dithiophosphate; and diluent oil.
5: 64 mg of TBN. KOH / g and 165 mg. Conventional additive packaging containing KOH / g mixed calcium salicylate detergent; dispersant; zinc dithiophosphate; and diluent oil.
6: Mixture of two different viscosity index improvers.
7: Group III base oil mixture of XHVI-5.2 and XHVI-8.2.

VW T4 test (PV 1449)
The experimental method used in the above example is as described in the standard test method defined in this test standard in accordance with the test standard obtained publicly for the VW T4 test (PV 1449).

Results and Discussion The formulations described in Tables 1 and 2 were tested using the test method. The results obtained are shown in Table 3.

*: Kinematic viscosity at 40 ° C. **: End value of test limit (VW T4 test (PV 1449)) is <200 (mm ² / s).
***: The end value of the test limit (VW T4 test (PV 1449)) is 5.0 mg. KOH / g.
***: TBN of new oil-end value of test TBN

  As is apparent from the above results, the formulation of Example 1 containing a phenolic antioxidant has a minimum terminal value of 5.0 mg. Compared to the formulation of Comparative Example 1 that does not meet KOH / g, the TBN retention by the VW T4 test (PV 1449) was improved.

In addition, the formulations of Examples 2-5, which also contain large amounts of phenolic antioxidants, have a test TBN limit VW T4 test (PV 1449) end value of 5.0 mg. Surprisingly, KOH / g was passed.
As is further apparent, the formulation of Example 6 containing an amine antioxidant also had improved TBN retention by the VW T4 test (PV 1449) compared to the formulation of Comparative Example 1.

Claims (10)

Base oil,
(A) One or more cleaning agents selected from a phenolate cleaning agent, a salicylate cleaning agent and a sulfonate cleaning agent, each of the one or more cleaning agents being independently measured by ISO 3771, 30 -350 mg. The detergent having a TBN (total base number) in the range of KOH / g;
(B) 3.5 wt% or more (based on the total weight of the lubricating oil composition) of one or more antioxidants selected from the group consisting of amine antioxidants and / or phenolic antioxidants;
A lubricating oil composition for an internal combustion engine having a sulfur ash content of 0.9% by weight or less and a phosphorus content of 0.04 to 0.1% by weight.   The lubricating oil composition according to claim 1, wherein the one or more antioxidants are present in an amount of 3.7% by weight or more based on the total weight of the lubricating oil composition.   The lubricating oil composition according to claim 1 or 2, wherein the one or more antioxidants are amine-based antioxidants.   The lubricating oil composition according to claim 3, wherein the one or more amine-based antioxidants are selected from alkylated diphenylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, and alkylated α-naphthylamine.   The lubricating oil composition according to claim 1 or 2, wherein the one or more antioxidants are phenolic antioxidants.   The one or more phenolic antioxidants are C6-C9 branched alkyls of 2,6-di-t-butylphenol, 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-benzenepropionic acid. 6. Lubricating oil composition according to claim 5, selected from esters and 4,4'-methylenebis (2,6-di-t-butylphenol).   The lubricating oil composition according to any one of claims 1 to 6, wherein the sulfur content of the composition is 1.2% by weight or less based on the total weight of the lubricating oil composition.   The lubricating oil composition according to any one of claims 1 to 7, wherein the phosphorus content of the composition is in the range of 0.04 to 0.09 wt% with respect to the total weight of the lubricating oil composition.   A method for lubricating an internal combustion engine, wherein the lubricating oil composition according to any one of claims 1 to 8 is applied to the internal combustion engine.   TBN levels were measured according to ISO 3771 and 5.0 mg. A method of using the lubricating oil composition according to any one of claims 1 to 8 in an internal combustion engine in a VW T4 test (PV 1449) in order to maintain KOH / g or more.