JP5106778B2 - Lubricant sludge dispersant - Google Patents

Description

The present invention relates to a lubricating oil sludge dispersant, a lubricating oil sludge dispersant composition, and a lubricating oil composition containing them.

Lubricating oils for internal combustion engines (for example, gasoline engines, diesel engines, gas engines) and drive system lubricating oils (for example, gear oils, hydraulic oils, automatic transmission oils, continuously variable transmission oils, power steering oils, etc. for automobiles) When used for a long time, as the lubricating oil deteriorates, various troubles are induced in the internal combustion engine and the drive system part, such as an increase in dirt and wear of the lubricated part due to the generation of sludge and an increase in power loss. In particular, in the case of diesel engine oil, high dispersion performance is required because suit is mixed. For this reason, various additives for dispersing sludge and suit in lubricating oil have been proposed. Examples thereof include succinimide compounds, succinamide compounds, or boronated derivatives thereof (see Patent Documents 1 to 3); poly (meth) acrylate compounds (see Patent Document 4).
However, although the lubricating oil composition containing the succinic dispersant is satisfactory in sludge dispersion performance, it has a problem of high viscosity at low temperature, particularly low temperature CCS (cold cranking simulator) viscosity. The lubricating oil composition containing the poly (meth) acrylate-based dispersant has not been sufficient in sludge dispersion performance.
In addition, conventional poly (meth) acrylate-based dispersants generally have poor shear stability due to mechanical shearing, and further have a problem that they are easily emulsified by mixed water (poor demulsibility). It was.
Japanese Patent Laid-Open No. 07-251056 JP-A-9-176673 JP 2005-162968 A JP 2002-145961 A

It is an object of the present invention to provide a lubricating oil sludge dispersant that can maintain a low temperature viscosity, particularly a low temperature CCS viscosity, is excellent in sludge dispersion performance, and is excellent in shear stability and demulsibility.

As a result of intensive studies, the present inventors have found that the above object can be achieved by using a specific polymer, and have reached the present invention.
That is, the sludge dispersant of the present invention is characterized by a weight average molecular weight of 1,000 to 10,000, 60 to 99% by weight of the following monomer (a), and 1 to 40% by weight of the following monomer. The gist of the present invention is that it is a sludge dispersant for lubricating oil comprising (b) and a polymer (A) comprising 0 to 11% by weight of the following monomer (c) as a constituent monomer.
Furthermore, the present invention is a sludge dispersant composition for lubricating oil comprising the above sludge dispersant and a lubricating base oil; and a lubricating oil composition containing these.
(A) an alkyl (meth) acrylate having an alkyl group having 8 to 36 carbon atoms (b) a hydroxyl group-containing monomer, an amino group-containing monomer, an amide group-containing monomer, and the general formula (1) One or more polar group-containing monomers selected from the group consisting of ether group-containing monomers CH ₂ ═C (R ¹ ) —COO (A—O) _n —R ² (1)
[Wherein, R ¹ is a hydrogen atom or a methyl group, A is an alkylene group having 2 to 4 carbon atoms, R ² is an alkyl group having 8 to 36 carbon atoms, and n is an integer of 1 to 20. ]
(C) Alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms

The sludge dispersant for lubricating oil and the lubricating oil composition of the present invention have good sludge dispersibility and can maintain a low CCS viscosity at a low temperature. Furthermore, it is excellent in shear stability and demulsibility.

The alkyl (meth) acrylate (a) having an alkyl group having 8 to 36 carbon atoms, which is one of the monomers constituting the polymer (A) in the present invention, will be described.

(A) includes linear alkyl (meth) acrylates and branched alkyl (meth) acrylates.
Examples of linear alkyl (meth) acrylates include n-octyl, n-nonyl, n-decyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-octadecyl methacrylate, and these And acrylates corresponding to the above.

Examples of the branched alkyl (meth) acrylate include isooctyl, 2-ethylhexyl, isononyl, isodecyl, isododecyl, 2-methylundecyl, isotridecyl, 2-methyldodecyl, isotetradecyl, 2-methyltridecyl, isopentadecyl, 2 -Methyltetradecyl, 2-hexyldecyl, 2-hexyldecyl, 2-octyldodecyl, 2-decyltetradecyl, 2-dodecylhexadecyl, 2-tetradecyloctadecyl, 2-hexadecyleicosyl (meth) acrylate, And acrylates corresponding to these.

(A) may be a combination of two or more selected from the group consisting of the above linear alkyl (meth) acrylates and branched alkyl (meth) acrylates.
In the case of combined use, two or more kinds of alkyl (meth) acrylates may be mixed, and an alkyl (meth) acrylate obtained from a mixture of two or more kinds of alcohol and (meth) acrylic acid or an ester-forming derivative thereof. There may be.
As a combination in the case of the combined use, any of a combination of a straight chain and a branch, a combination of two or more of the straight chains, a combination of two or more of the branches, and a combination thereof may be used.
Examples of the mixture of two or more alcohols include a mixture of linear and branched alcohols, such as oxo alcohol, and examples of oxo alcohol include “Neodol 23” and “Neodol 45” (manufactured by Shell Chemical Co., Ltd.), “ Examples include Dovanol 23 and Dovanol 45 (Mitsubishi Chemical Co., Ltd.), and Oxocol 1213 and Oxocol 1415 (Nissan Chemical Co., Ltd.).

Among (a), from the viewpoint of low-temperature viscosity, an alkyl group having 8 to 17 (more preferably C8 to 15) carbon atoms of the alkyl group (hereinafter sometimes simply referred to as “C”) is preferable. It is a (meth) acrylate, more preferably an alkyl (meth) acrylate having at least one branched alkyl (meth) acrylate.

The monomer (b) which is one of the monomers constituting the polymer (A) in the present invention will be described.
(B) includes a hydroxyl group-containing monomer (b1), an amino group-containing monomer (b2), an amide group-containing monomer (b3), and an ether group-containing monomer (b4) represented by the general formula (1). ), One or more polar group-containing monomers selected from the group consisting of polar groups [for example, hydroxyl group in amino group-containing monomer (b1), amino group-containing monomer (b2 In the molecule, an amino group in amide group-containing monomer (b3), and an ether group or a polyether group in monomer (b4) represented by general formula (1)] Common.
^{_{CH 2 = C (R 1)}} -COO (A-O) n -R 2 (1)

In the formula, R ¹ is a hydrogen atom or a methyl group, A is an alkylene group having 2 to 4 carbon atoms, R ² is an alkyl group having 8 to 36 carbon atoms, and n is an integer of 1 to 20.

Hereinafter, (b1) to (b4) will be described in order.

Examples of the hydroxyl group-containing monomer (b1) include the following (b11) to (b15).

(B11) a hydroxyl group-containing (meth) acrylate;
Examples thereof include (meth) acrylate represented by the general formula (4) and (meth) acrylate of polyhydric alcohol having 3 to 8 hydroxyl groups.

^{_{CH 2 = C (R 1)}} -COO- (A-O) m -H (4)
In the formula, R ¹ and A are the same as in the general formula (1), and m is an integer of 1 to 20 (preferably 1).
Examples of the (meth) acrylate represented by the general formula (4) include 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl (meth) acrylate, and Examples include C2-4 hydroxyalkyl (meth) acrylates such as 2-hydroxyethoxyethyl (meth) acrylate, and polyalkylene glycol mono (meth) acrylates (the number of alkylene groups is 2 to 20).

Examples of the polyhydric alcohol having 3 to 8 hydroxyl groups constituting the (meth) acrylate of the polyhydric alcohol having 3 to 8 hydroxyl groups include, for example, C3-12 alkane polyols, intramolecular or intermolecular dehydrates, C2-4 alkylene oxide adducts, and saccharides (eg, glycerin, pentaerythritol, sorbitol, sorbitan, diglycerin, sucrose, methyl glucoside, etc.), and (meth) acrylates thereof include glycerin mono- and di- (Meth) acrylate, trimethylolpropane mono- and di- (meth) acrylate, sucrose (meth) acrylate, and the like.

(B12) C2-C12 alkenol;
Vinyl alcohol (formed by hydrolysis of vinyl acetate units), C3-12 alkenol [(meth) allyl alcohol, (iso) propenyl alcohol, crotyl alcohol, 1-buten-3-ol, 1-butene-4 -Ol, 1-octenol, 1-undecenol and 1-dodecenol, etc.], and their C2-4 alkylene oxide adducts.
(B13) C4-12 alkenediol;
Examples include 2-butene-1,4-diol.
(B14) a hydroxyl group-containing alkenyl ether having an alkenyl group having 3 to 12 carbon atoms;
For example, C1-6 hydroxyalkyl C3-12 alkenyl ether [for example, 2-hydroxyethylpropenyl ether, and C3-12 alkenyl ether of polyhydric alcohol mentioned in (b112) {trimethylolpropane mono- and di- (meth) allyl ether And sucrose (meth) allyl ether, etc.}] and their C2-4 alkylene oxide adducts.

(B15) a hydroxyl group-containing aromatic monomer;
These include o-, m- or p-hydroxystyrene, and their C2-4 alkylene oxide adducts.

Of these, (b1) is preferably (b11), (b12), (b14) and (b15), particularly (b11) from the viewpoint of low temperature viscosity. Particularly preferred are 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate.

Examples of the amino group-containing monomer (b2) in the monomer (b) include the following (b21) to (b23).

(B21) an amino group-containing (meth) acrylate represented by the following general formula (2);

In the formula, R ¹ is a hydrogen atom or a methyl group, R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m is an integer of 2 to 6.

Specific examples of (b21) include [(mono-C1-4 alkyl) amino C2-6 alkyl (meth) acrylate {aminoethyl, aminopropyl, methylaminoethyl, ethylaminoethyl, butylaminoethyl and methylaminopropyl ( Meth) acrylate}, di-C1-4 alkylamino C2-6 alkyl (meth) acrylate {dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and dibutylaminoethyl (meth) acrylate}] and their (meta ) Amino group-containing (meth) acrylamide corresponding to acrylate.

(B22) an amino group-containing heterocyclic monomer;
Amino group-containing heterocyclic acrylic monomer [morpholino-C2-4 alkyl (meth) acrylate {morpholinoethyl (meth) acrylate}], vinyl-substituted heterocyclic amine [vinylpyridine (4- and 2-vinylpyridine) ], N-vinylpyrrole and N-vinylpyrrolidine.

(B23) an amino group-containing aromatic monomer;
Aminostyrenes such as aminostyrene and (di) methylaminostyrene.

Among (b2), from the viewpoint of sludge dispersibility, (b21) is preferable, and di-C1-4 alkylamino C2-6 alkyl (meth) acrylate, particularly dimethylaminoethyl (meth) acrylate and diethylaminoethyl are more preferable. (Meth) acrylate.

Among the monomers (b), examples of the monomer (b3) containing an amide group include the following (b31) and (b32).

(B31) a monomer represented by the following general formula (3);

In the formula, R ¹ is a hydrogen atom or a methyl group, R ⁵ and R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a hydroxyalkyl group having 1 to 4 carbon atoms, and a dialkyl (1 to 4 carbon atoms). ) A group selected from aminomethylene (C1-4) groups.

Specific examples of (b31) include the following (b311) and (b312).
(B311) unsubstituted and alkyl-substituted acrylamide;
For example, acrylamide (hereinafter abbreviated as AAm), methacrylamide, N-mono-C1-4 alkyl and N, N-di-C1-4 alkyl-substituted (meth) acrylamide [(di) methyl, (di) ethyl, (Di) isopropyl, (di) n-butyl and (di) isobutyl (meth) acrylamide etc.].
(B312) hydroxyalkyl-substituted acrylamide;
For example, N-mono-C1-4 hydroxyalkyl and N, N-di-C1-4 hydroxyalkyl substituted (meth) acrylamide [N-hydroxymethyl, N, N-dihydroxymethyl, N, N-di-2-hydroxy Ethyl, N, N-di-4-hydroxybutyl (meth) acrylamide, etc.].

(B32) N-vinylcarboxylic acid amide:
For example, acyl N-vinylcarboxylic acid amides [N-vinylformamide, N-vinylacetamide, N-vinyl n- and i-propionamide and N-vinylhydroxyacetamide etc.] and N-vinyl lactams [N-vinylpyrrolidone etc. ].

Preferred among (b3) are (b311), particularly (meth) acrylamide and N-vinylpyrrolidone.

Of the monomer (b), the ether group-containing monomer (b4) represented by the general formula (1) will be described.
In the general formula (1), R ¹ is preferably a methyl group. A is an alkylene group having 2 to 4 carbon atoms, specifically, an ethylene group, 1,2- and 1,3-propylene group, 1,2-, 1,3- and 1,4-butylene group. It is done. Among A, an ethylene group, a 1,2-propylene group and a combination thereof are preferable.
n is an integer of 1 to 20, preferably 1 to 15, more preferably 1 to 10, and R ² is a linear or branched alkyl group having 8 to 36 carbon atoms.
Examples of the linear alkyl group include n-dodecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, n-octyl, n-nonyl, n-decyl, n-tridecyl and n-pentadecyl groups.
Examples of the branched alkyl group include isooctyl, 2-ethylhexyl, isononyl, isodecyl, isododecyl, 2-methylundecyl, isotridecyl, 2-methyldodecyl, isotetradecyl, 2-methyltridecyl, isopentadecyl, 2-methyltetra Examples include decyl, 2-hexyldecyl, 2-hexyldecyl, 2-octyldecyl, 2-decyltetradecyl, 2-dodecylhexadecyl, 2-tetradecyloctadecyl, and 2-hexadecyleicosyl groups.
R ² further includes a mixture of a linear C8-36 alkyl group and a branched C8-36 alkyl group.
Preferred among R ² is C8-17 (further C8-15) alkyl, especially branched C8-17 (further C8-15) alkyl, from the viewpoint of low temperature CCS viscosity.
Specific examples of (b4) include mono (meth) acrylate of (poly) oxyethylene monoalkyl (C8-15) ether and mono (meth) acrylate of (poly) oxypropylene monoalkyl (C8-15) ether. Is mentioned.

Among (b), from the viewpoint of dispersibility, (b1) and (b2), particularly (b2) are preferable.

The alkyl (meth) acrylate (c) having an alkyl group having 1 to 4 carbon atoms, which is used as a constituent monomer as necessary in the polymer (A) in the present invention, will be described.
Examples of (c) include methyl methacrylate, methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate.
Of these, methyl methacrylate is preferred from the viewpoint of low temperature viscosity.

In the polymer (A), based on the weight of all the constituent monomers of (A), (a) is 60 to 99% (unless otherwise specified,% represents% by weight), preferably 70 to 99%, more preferably 80 to 99%, and (b) is 1 to 40%, preferably 1 to 30%, more preferably 1 to 20%, particularly preferably 1 to 15%, particularly preferably 1 to 8%, and (c) is 0 to 11%, preferably 0 to 8%, more preferably 0 to 6%.

When (a) is less than 60%, the dispersibility is inferior because the aggregation of the object to be dispersed is promoted. When it exceeds 99%, the adsorptivity to the object to be dispersed is lowered and the dispersibility is inferior.
If (b) is less than 1%, the adsorptivity to the object to be dispersed becomes low, so that the dispersibility is inferior.
In addition, (b) has the said range preferable also from a viewpoint of demulsibility.
When only (b1) to (b3) are used as (b), the total of (b1) to (b3) is 1 to 40% based on the weight of all constituent monomers of (A), dispersibility From this viewpoint, it is preferably 1 to 20%, more preferably 1 to 10%, and particularly preferably 1 to 5%.
When only (b4) is used as (b), based on the weight of all constituent monomers of (A), (b4) is 1 to 40%, preferably 1 to 30% from the viewpoint of dispersibility, More preferably, it is 1 to 15%.
In the case of using methyl methacrylate as (c), from the viewpoint of dispersibility and CCS viscosity at low temperature, preferably, based on the weight of all constituent monomers of the polymer (A), methyl methacrylate is preferably 10% or less, More preferably, it is 7% or less, and particularly preferably 5% or less.

The polymer (A) in the present invention may further comprise other monomer (d) as required. Examples of the other monomer (d) include the following (d1) to (d7).

(D1) alkyl alkenyl ether;
Examples thereof include alkyl vinyl ethers having a C1-30 linear or branched alkyl group, alkyl (meth) allyl ethers, alkylpropenyl ethers and alkylisopropenyl ethers. Specifically, examples of the alkyl vinyl ether include methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, and n-octyl vinyl ether. Examples of the alkyl (meth) allyl ether include n-propyl allyl ether and n-butyl allyl ether. It is done. Of these, preferred are alkyl vinyl ethers (more preferred are those having a C1-8 alkyl group, particularly n-butyl vinyl ether and n-octyl vinyl ether), and alkyl (meth) allyl ether (more preferred is n -Propyl allyl ether).

(D2) an alkyl (meth) acrylate having an alkyl group having 5 to 7 carbon atoms;
For example, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, etc. are mentioned.

(D3) fatty acid vinyl ester;
Fatty acid vinyl esters having an alkyl group constituting a fatty acid with a C of 1 to 30 (straight chain or branched alkyl group) are included, and the alkyl group is the same group as the alkyl of the above (d1), preferably C is Alkyl groups of 1 to 22, more preferably 1 to 10 are mentioned. Specific examples include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl hexanoate, vinyl heptanoate, vinyl 2-ethylhexanoate and vinyl n-octanoate.

(D4) Aliphatic and alicyclic hydrocarbon unsaturated monomers:
C2-20 alkene (ethylene, propylene, isobutylene, etc.), C4-12 alkadiene (butadiene, isoprene, etc.), C2-16 acetylene and substituted acetylene, and alicyclic hydrocarbon vinyl monomers (cyclohexene, diene) Cyclopentadiene, vinylcyclohexene, etc.).

(D5) Aromatic hydrocarbon vinyl monomer:
For example, styrene, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, 4-ethylstyrene, 4-isopropylstyrene, 4-butylstyrene, 4-phenylstyrene, 4-cyclohexylstyrene, 4-benzylstyrene, 4 -Crotylbenzene, 2-vinylnaphthalene and the like.

(D6) Vinyl ketones: For example, C1-8 alkyl or aryl vinyl ketones [methyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl ketone, etc.].

(D7) diester of unsaturated dicarboxylic acid; for example, alkyl (C1-12), cycloalkyl (C4-24) and aralkyl (C7-18) of unsaturated dicarboxylic acid [maleic acid, fumaric acid, itaconic acid, etc.] Among them, C1-8 alkyl diesters [dimethyl maleate, dimethyl fumarate, diethyl maleate, dioctyl maleate, etc.] are preferable.

Preferred among (d) are (d2), (d5) and a combination of two or more of these.

When the polymer (A) has other monomer (d) as a constituent monomer, preferably (d) is 30% based on the weight of all constituent monomers of the polymer (A). Hereinafter, it is further preferably 20% or less, particularly preferably 10% or less.

Further, based on the weight of all the constituent monomers of the polymer (A), the sum of (a) and (b) is 70% or more, preferably 80% or more, and more preferably 90% or more.
When the sum of (a) and (b) is 70% or more, the dispersibility is further improved.

The polymer (A) has a weight average molecular weight of usually 1,000 to 10,000, preferably 3,000 to 10,000, more preferably 5,000, from the viewpoints of dispersibility, shear stability and demulsibility. -10,000.
The dispersity (weight average molecular weight / number average molecular weight) is preferably 1.1 to 2.0, more preferably 1.1 to 1.6, and particularly preferably 1.1 to 1.4. The weight average molecular weight (hereinafter abbreviated as Mw) and the number average molecular weight (hereinafter abbreviated as Mn) are numerical values obtained by conversion to polystyrene by gel permeation chromatography.

The polymer (A) can be produced by a known radical polymerization. Examples of the radical polymerization include solution polymerization, bulk polymerization, and emulsion polymerization, and solution polymerization is preferable. Solution polymerization can be usually performed by heating and stirring the monomer mixture in the presence of a polymerization initiator, an organic solvent, and, if necessary, a chain transfer agent. The polymerization initiator includes an initiator selected from the group consisting of azo initiators, peroxide initiators, redox initiators, and organic halogen compound initiators. Examples of the azo initiator include azobisisobutyronitrile, azobiscyanovaleric acid and its salt (for example, hydrochloride), 2,2′-azobis (2-amidinopropane) hydrochloride, 2,2′-azobis (2- Methyl-N- (2-hydroxyethyl) propionamide, etc. Peroxide initiators include inorganic peroxides (hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, etc.), organic peroxides. [Benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, succinic acid peroxide, di (2-ethoxyethyl) peroxydicarbonate, etc.] Examples of redox catalysts include alkali metal Sulphite or bisulfite (eg, ammonium sulfite, ammonium bisulfite, etc.), salt And a combination of a reducing agent such as ferrous chloride, ferrous sulfate, and ascorbic acid and an oxidizing agent such as alkali metal persulfate, ammonium persulfate, hydrogen peroxide, and organic peroxide.
Organic solvents include, for example, solvent refined oils as high boiling solvents, high viscosity index oils containing isoparaffins and / or hydrocracking, hydrocarbon synthetic oils, ester synthetic oils, naphthenic oils, and other hydrocarbon solvents (Pentane, hexane, etc.), aromatic solvents (toluene, xylene, etc.), alcohol solvents (octal, butanol, etc.), ketone solvents (methyl isobutyl ketone, methyl ethyl ketone, etc.), amide solvents (N, N-dimethylformamide) , N-methylpyrrolidone, etc.) and sulfoxide solvents (dimethyl sulfoxide, etc.).
Examples of the chain transfer agent include thiocarboxylic acids (n-lauryl mercaptan, mercaptoethanol, mercaptopropanol etc.), thiolic acids (thioglycolic acid, thiomalic acid etc.), secondary alcohols (isopropanol etc.), amines (di Butylamine, etc.), hypophosphites (sodium hypophosphite, etc.) and the like. The amount of the chain transfer agent in the case of obtaining a low molecular weight polymer is usually 0. 1 to 10%, preferably 1 to 5%. The polymerization temperature is 30 to 140 ° C, preferably 50 to 130 ° C, particularly preferably 70 to 120 ° C. In addition to the method of initiating polymerization by heat, a method of initiating polymerization by irradiating with radiation, electron beam, ultraviolet rays or the like can also be employed. Preferred is a temperature-controlled solution polymerization method. Furthermore, the copolymerization may be either random addition polymerization or alternating copolymerization, and may be either graft copolymerization or block copolymerization.

The sludge dispersant for lubricating oil of the present invention is usually composed only of the polymer (A).

The lubricating oil sludge dispersant according to the present invention is added as a component in the lubricating oil composition, so that not only the sludge dispersing effect of the lubricating oil composition but also the viscosity at the low temperature of the lubricating oil composition, particularly the low temperature (for example, − 40 or -35 ° C.) CCS viscosity can be kept low. Furthermore, it has excellent demulsibility.

Moreover, the sludge dispersant for lubricating oil of the present invention is excellent in shear stability, and the kinematic viscosity at 100 ° C. of a 10 wt% mineral oil solution of the polymer (A) measured by the method of JASO M347-95. The reduction rate is preferably 5% or less, more preferably 3% or less.
“YUBESE3” (manufactured by SK Corporation) can be used as the mineral oil used in the above measurement. Since the kinematic viscosity reduction rate is small and the shear stability is excellent, the life of the lubricating oil composition is extended because the viscosity reduction due to mechanical shearing is small.

In the sludge dispersant for lubricating oil of the present invention, the polymer (A) may be added to the base oil as it is, but it may be added in the form of the following sludge dispersant composition for lubricating oil.

The sludge dispersant composition for lubricating oil of the present invention comprises a sludge dispersant comprising the polymer (A) and a diluent and / or other additives. That is, the sludge dispersant composition for lubricating oil of the present invention comprises a polymer (A) and a diluent, a polymer (A) and other additives, or a polymer (A) and a diluent and other additives, One of them.

Examples of the diluent include the same organic solvents that can be used in the polymerization step described above, and the lubricating base oil described below.

As other additives, the following conventionally known ones can be used.
Viscosity index improvers [polyalkyl (meth) acrylates, olefin copolymers, polyisobutylenes, etc.]; dispersants other than the present invention [polyalkenyl succinimides (bis- and mono-polybutenyl succinimides), Mannich condensation Detergents [basic, overbased or neutral metal salts {overbased or alkaline earth metal salts of sulfonates (petroleum sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, etc.)] }, Salicylates, phenates, naphthenates, carbonates, phosphonates and mixtures thereof]; antioxidants [hindered phenols, aromatic secondary amines and mixtures thereof, etc.]; antifoaming agents [Silicon oil, metal soap, fatty acid ester and Phosphate compounds, etc.]; oiliness improvers [long chain fatty acids and their esters (such as oleic acid and oleic acid esters), long chain amines and their amides (such as oleylamine and oleylamide)]; friction wear modifiers [molybdenum And zinc compounds (such as molybdenum dithiophosphate, molybdenum dithiocarbamate and zinc dialkyldithiophosphate)]; extreme pressure agents [sulfur compounds (mono- and di-sulfides, sulfoxides and sulfur phosphide compounds), phosphide compounds And chlorinated compounds (chlorinated paraffins, etc.); demulsifiers [quaternary ammonium salts (tetraalkylammonium salts), sulfated oils, phosphates (polyoxyethylene-containing nonionic surfactant phosphates) Eto), etc.]; corrosion inhibitors [nitrogen-containing compound (benzotriazole and 1,3,4 Chiojiazoriru-2,5-bis dialkyl dithiocarbamate), etc.].

Each content based on the total weight of the sludge dispersant composition of the sludge dispersant, diluent and other additives of the present invention in the sludge dispersant composition for lubricating oil is preferably 0.1 to 0.1. 99%, more preferably 1-90%, diluent is preferably 1-99.9%, more preferably 10-99%, other additives are preferably 1-50%, more preferably 2-30% It is.
In addition, a part or all of the other additives may be added in the step of preparing the lubricating oil composition described below.

The lubricating oil composition of the present invention comprises the lubricating base oil and the sludge dispersant for lubricating oil of the present invention as essential components, and the content of the polymer (A) is usually 0.00 based on the weight of the lubricating oil composition. 01 to 30%, preferably 0.1 to 20%, more preferably 1 to 10%.

As the diluent of the sludge dispersant composition for lubricating oil of the present invention, or the lubricating base oil that can be used in the lubricating oil composition, solvent refined oil mainly composed of paraffin, isoparaffin, naphthene, hydrotreated oil, hydrogen Chemically decomposed oils, ester-based and poly-α-olefin-based synthetic oils and the like may be mentioned, and these may be used alone or in combination of two or more.
The lubricating base oil is usually 50 to 99%, preferably 60 to 99%, more preferably 70 to 99% based on the weight of the lubricating oil composition.
The kinematic viscosity at 100 ° C. of the lubricating base oil in the present invention is usually 1 to 10 mm 2 / s, preferably 1 to 8 mm 2 / s, particularly preferably 2 to 5 mm 2 / s, and the viscosity index is usually 80 or more, preferably 100. ~ 250. When the base oil has a kinematic viscosity of less than 1 mm 2 / s, during use, the oil content is remarkably evaporated due to the temperature rise, or the lubricating part is exposed to high pressure, and the oil film is cut off and is likely to be seized. On the other hand, if it exceeds 10 mm2 / s, the viscous resistance increases and energy loss is likely to occur. When the viscosity index of the base oil is less than 80, the viscosity-temperature characteristic is deteriorated.
The pour point (JIS K2269) of the base oil is preferably −5 ° C. or lower, and more preferably −10 ° C. to −70 ° C. If the pour point of the base oil is within this range, the amount of precipitated wax is small and the low temperature viscosity is good.

The content of the other additives in the lubricating oil composition of the present invention is as follows.
Viscosity index improvers are 0-30%, preferably 1-20%, more preferably 1-10%, particularly preferably 1-5%; dispersants other than the present invention are 0-15%, preferably 0-10. %, More preferably 0 to 5%; detergent 0 to 15%; antioxidant 0.1 to 3%; antifoam 2 to 1500 ppm; oil improver 0 to 3%; friction wear modifier 0-8%; extreme pressure agent 0-25%; demulsifier 0-7%; corrosion inhibitor 0-5%; total of other additives 0-30%, preferably 0-25% It is.

The lubricating oil composition of the present invention can maintain not only the sludge dispersion effect but also the viscosity at low temperatures, particularly the CCS viscosity at low temperatures (for example, −40 and −35 ° C.). Furthermore, since the anti-emulsification property is excellent and the viscosity decrease due to mechanical shearing is small, the life of the lubricating oil composition is long.

The lubricating oil composition of the present invention comprises gear oil (for industrial use and automobile use), transmission oil [automatic transmission oil (automatic transmission oil, toroidal CVT oil, belt CVT oil, etc.) manual transmission oil, traction oil, hydraulic oil ( It can be used in a wide range of applications such as hydraulic oil, power steering oil, shock absorber oil, etc.) and engine oil (gasoline, diesel, etc.).
Particularly preferred is the use for transmission oils and engine oils, particularly preferably gasoline engine oils and diesel engine oils, most preferably automotive gasoline engine oils and diesel engine oils for low viscosity grades (0W and 5W) and lubrication Longer oil life and improved fuel efficiency can be achieved.

<Example>
The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In addition, the part in a manufacture example, an Example, and a comparative example represents a weight part.
(Method for measuring weight average molecular weight by GPC)
Apparatus: GPC HLC-8020 manufactured by Tosoh Corporation
Guard column: HxlH 1 column: TSK gel GMHxl 2 Measurement temperature: 40 ° C
Sample solution: 0.25% THF solution injection amount: 100 μl
Detector: Refractive index detector Standard: Polystyrene

<Production of Sludge Dispersant Composition Composed of Polymer and Diluent>
Examples 1-3 and Comparative Examples 1-2;
In a reaction vessel equipped with a stirrer, heating / cooling device, thermometer, dropping funnel, and nitrogen blowing tube, 11 parts of mineral oil (“YUBASE3”: manufactured by SK Corporation) was charged. The monomer shown, dodecyl mercaptan (chain transfer agent), and 2,2′-azobis (2,4-dimethylvaleronitrile) (polymerization initiator) were charged, and the monomer was stirred and mixed at 20 ° C. A solution was prepared and charged into the dropping funnel. After carrying out nitrogen substitution of the gas phase part of the reaction vessel, the monomer solution was added dropwise at 85 ° C. for 2 hours under hermetically sealed, and aging was carried out at 85 ° C. for 2 hours from the end of the addition. ) To (B-2) were obtained, respectively, to obtain polymer mineral oil dilutions [sludge dispersant compositions (A′-1) to (B′-2)]. The polymer Mw and Mw / Mn are shown in Table 1.

Abbreviations in Table 1 are as follows.
i-C10-MA: isodecyl methacrylate n-C12-MA: n-dodecyl methacrylate i-C12-MA: isododecyl methacrylate n-C13-MA: n-tridecyl methacrylate i-C13-MA: isotridecyl methacrylate DMAEMA : Dimethylaminoethyl methacrylate MMA: Methyl methacrylate ABVN: 2,2′-azobis (2,4-dimethylvaleronitrile)

Shear stability test;
11.23 parts of the above sludge dispersant compositions (A′-1) to (B′-2) and 88.77 parts of mineral oil (“YUBASE3”) are mixed and dissolved, and 10 parts by weight of the polymer is dissolved. A mineral oil solution containing was prepared.
According to the above-mentioned method of JASO M347-95, the kinematic viscosity at 100 ° C. before the test (unit: mm ² / s) and the kinematic viscosity at 100 ° C. after the test (unit: mm ² / s) were measured. % (%) [(Kinematic viscosity before test−kinematic viscosity after test) ÷ kinematic viscosity before test] × 100.
The results are shown in Table 2.

<Preparation of lubricating oil composition>
Examples 4-6, Comparative Examples 3-4
Each of the above sludge dispersions in a lubricating base oil (mixture of 20 parts YUBASE3 and 80 parts YUBASE4: 100 ° C. kinematic viscosity: 4.0 mm 2 / s, viscosity index: 120, CCS viscosity at −35 ° C. of 2800 mPa · s) Agent compositions (A′-1) to (B′-2) were dissolved in predetermined amounts shown in Table 3 below to prepare lubricating oil compositions.

<Evaluation of lubricating oil composition>
These lubricating oil compositions were measured for carbon black dispersibility, viscosity index, CCS viscosity at −35 ° C., and demulsibility. The results are shown in Table 3.

Carbon black dispersibility test (static temperature 25 ° C.);
Carbon black dispersion sample by putting 1.5g of carbon black (product name "MB-100", manufactured by Mitsubishi Kasei Co., Ltd.) and 48.5g of lubricating oil composition into a 200ml container and mixing with a homogenizer at 29000 ± 1000rpm for 10 minutes. It was. In a 70 ml glass container, 50 mg of carbon black dispersion sample and 50 ml of xylene were put, and the container was covered, shaken vigorously 10 times, and allowed to stand at room temperature for 7 days.
After standing, the presence or absence of sediment and the blackness of the supernatant were compared visually. The evaluation criteria are as follows.
○: There is no sediment and the blackness of the supernatant is high. Dispersibility is good. X: The sediment is thin and the supernatant is thin. Blackness is poor.

Measurement of the viscosity index;
It was carried out by the method of JIS-K-2283.

Measurement of CCS viscosity;
It was performed by the method of ASTM D5923.

Test of demulsibility;
This was performed according to the method of JIS K 2520. Take 40 ml of lubricating oil composition and 40 ml of pure water in a test tube, keep it at the test temperature (54 ° C), stir the stirring plate at 1500 rpm for 5 minutes, stop the stirring, water layer after 20 minutes, oil layer, The volume ratio of the emulsified layer was measured.

The sludge dispersant for lubricating oil and the lubricating oil composition of the present invention are used for driving system lubricating oils [for gear equipment (manual transmission oil, differential oil, etc.), automatic transmission oil (automatic transmission), etc. for transportation equipment and various machine tools. Oil, belt CVT oil, toroidal CVT oil, etc.)], hydraulic oil [mechanical oil, power steering oil, shock absorber oil, etc.], and engine oil [gasoline, diesel, etc.].

Claims (8)

The weight average molecular weight is 1,000 to 10,000, 60 to 92% by weight of the following monomer (a), 1 to 30% by weight of the following monomer (b), and 5 to 11% by weight of the following monomer. A lubricant sludge dispersant comprising a polymer (A) having a monomer (c) as a constituent monomer, wherein the monomer (b) has an amino group-containing (meta) group represented by the general formula (2) Acrylate A lubricant sludge dispersant.
[Wherein, R ¹ is a hydrogen atom or a methyl group, R ³ and R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and m is an integer of 2 to 6. ]
(A) an alkyl (meth) acrylate having an alkyl group having 8 to 36 carbon atoms, which is essentially an alkyl (meth) acrylate having a branched alkyl group having 8 to 36 carbon atoms, (b) an amino group-containing monomer (c) Alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms   The sludge dispersant for lubricating oil according to claim 1, wherein the total of the monomer (a) and the monomer (b) constituting the polymer (A) is 70% by weight or more.   The sludge dispersion for lubricating oil according to claim 1 or 2, wherein the 10% by weight mineral oil solution of the polymer (A) has a kinematic viscosity reduction rate at 100 ° C of 5% or less as measured by the method of JASO M347-95. Agent.   A sludge dispersant composition for lubricating oil comprising the lubricant sludge dispersant according to any one of claims 1 to 3, and a diluent and / or other additives. A lubricating oil composition comprising a lubricating base oil and the lubricating oil sludge dispersant according to any one of claims 1 to 3 as essential components, and containing the sludge dispersant in an amount of 0.01 to 30% by weight based on the weight of the lubricating oil. object. The lubricating oil composition according to claim 5, wherein the lubricating base oil has a kinematic viscosity at 100 ° C. of 1 to 10 mm ² / s and a viscosity index of 80 or more.   The lubricating oil composition according to claim 5 or 6, wherein the lubricating base oil has a viscosity index of 100 to 250.   The lubricating oil composition according to any one of claims 5 to 7, which is a lubricating oil composition selected from the group consisting of gear oil, transmission oil, traction oil, hydraulic oil and engine oil.