JP6169987B2 - Grease composition - Google Patents

Description

  The present invention relates to a grease composition used for lubrication between an aluminum-based member and a steel-based member.

  Grease compositions are widely used for lubricating various sliding parts of automobiles and various industrial machines because they are easier to seal than lubricating oils, and the size and weight of machines can be reduced.

  For example, in Patent Document 1, as a grease composition used for a vehicle hub unit bearing incorporated in automobiles, railways, etc., a base oil composed of at least one of mineral oil and synthetic oil, aromatic urea as a thickener, and In addition, a water-resistant grease comprising three specific types of rust preventives is disclosed.

JP 2008-13624 A

By the way, in recent years, from the viewpoint of reducing the weight of machine parts, it has been increasingly used by replacing a part of a steel-based member with an aluminum-based member at a place with a relatively large contact area and a relatively light load. The sliding part between the steel member and the steel member is increasing.
For example, when the grease composition described in Patent Document 1 is used for lubrication of a sliding portion between such an aluminum-based member and a steel-based member, since the contact area between the members is large, the sliding portion Poor lubrication is likely to occur, and seizure is likely to occur.
As a simple solution to this problem, it is conceivable to increase the amount of the grease composition used for the sliding part. However, from the viewpoint of simplifying the sealing mechanism and reducing the torque, a small amount of grease composition can be used for lubricating performance. There are many parts that require this, and it is difficult to increase the amount of the grease composition in such parts.

  The present invention has been made to solve the above-mentioned problems, and is excellent in the effect of suppressing the occurrence of poor lubrication when used for lubrication of a sliding portion between an aluminum-based member and a steel-based member. An object of the present invention is to provide a grease composition.

The inventors have found that a grease composition obtained by blending a predetermined amount of an aliphatic diurea and a dicarboxylic acid ester with a base oil having a specific kinematic viscosity can solve the above-mentioned problems, and has completed the present invention. I let you.
That is, the present invention relates to the following [1] to [6].
[1] A base oil comprising at least one selected from synthetic oils other than mineral oil and dicarboxylic acid ester, and having a kinematic viscosity at 40 ° C. of 5 to 40 mm ² / s, (A) aliphatic diurea, and (B ) A grease composition comprising a dicarboxylic acid ester and used for lubrication between an aluminum-based member and a steel-based member,
The grease composition, wherein the blending amount of the component (A) is 5 to 40% by mass and the blending amount of the component (B) is 0.1 to 5.0% by mass with respect to the total amount of the grease composition.
[2] Further, as (C) rust inhibitor, (C-1) carboxylic acid rust inhibitor, (C-2) amine rust inhibitor, and (C-3) carboxylate rust inhibitor are selected. The grease composition according to the above [1], comprising one or more of the above.
[3] The grease composition according to [1] or [2], further comprising (D) an antioxidant.
[4] The grease composition according to any one of [1] to [3], wherein (A) the aliphatic diurea is a compound represented by the following general formula (a1).
^{R 1 -NHCONH-R 3 -NHCONH-} R 2 (a1)
(In formula (a1), R ¹ and R ² each independently represents a monovalent chain hydrocarbon group having 6 to 24 carbon atoms. R ³ is a divalent aromatic having 6 to 18 carbon atoms. Indicates a hydrocarbon group.)
[5] The grease composition according to [4], wherein R ¹ and R ² in the general formula (a1) are each independently a monovalent chain hydrocarbon group having 6 to 10 carbon atoms.
[6] The grease composition according to any one of the above [1] to [5], wherein the (B) dicarboxylic acid ester is a compound represented by the following general formula (b1).
_{^{R 4 OOC- (R 6) n}} -COOR 5 (b1)
(In formula (b1), R ⁴ and R ⁵ each independently represents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. R ⁶ is a divalent hydrocarbon having 1 to 20 carbon atoms. Represents a group, and n represents 0 or 1.)

  The grease composition of the present invention is excellent in the effect of suppressing the occurrence of poor lubrication when used for lubrication of a sliding portion between an aluminum-based member and a steel-based member.

  In the present invention, for example, a composition defined as “a composition formed by blending the component (A) and the component (B)” is only “a composition containing the component (A) and the component (B)”. And “a composition containing a modified product in which the component is modified instead of at least one of the component (A) and the component (B)” or “the component (A) and the component (B) react. Also included are “compositions comprising the resulting reactants”.

The grease composition of the present invention comprises one or more kinds selected from synthetic oils other than mineral oil and dicarboxylic acid ester, and a base oil having a kinematic viscosity at 40 ° C. of 5 to 40 mm ² / s is added to (A) aliphatic A grease composition containing diurea and (B) dicarboxylic acid ester and used for lubrication between an aluminum-based member and a steel-based member.
The grease composition of the present invention preferably further contains (C) a rust inhibitor and / or (D) an antioxidant, and other additives other than the above components (A) to (D). It may be.
Hereinafter, each component mix | blended with the grease composition of this invention is demonstrated.

<Base oil>
The base oil blended in the grease composition of the present invention comprises one or more selected from synthetic oils other than mineral oil and dicarboxylic acid ester, and has a kinematic viscosity at 40 ° C. of 5 to 40 mm ² / s. If it is.
Examples of mineral oils that can be used include distillate oils obtained by subjecting paraffin base crude oil, intermediate base crude oil, or naphthenic crude oil to atmospheric distillation or atmospheric distillation residue oil under reduced pressure, and these distillate oils. Examples include refined oils obtained by refining in accordance with conventional methods, specifically solvent refined oils, hydrogenated refined oils, dewaxed oils, and clay-treated oils.

The synthetic oil is a synthetic oil other than the dicarboxylic acid ester blended as the component (B), and examples thereof include synthetic oils other than diester oils such as hydrocarbon oils, aromatic oils, and ether oils. It is done.
Examples of hydrocarbon oils include normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, poly-α-olefin (PAO) such as 1-decene and ethylene co-oligomer, and hydrides thereof. .
Examples of the aromatic oil include alkylbenzenes such as monoalkylbenzene and dialkylbenzene, and alkylnaphthalenes such as monoalkylnaphthalene, dialkylnaphthalene and polyalkylnaphthalene.
Examples of the ether oil include polyglycols such as polyethylene glycol, polypropylene glycol, polyethylene glycol monoether, and polypropylene glycol monoether, or monoalkyl triphenyl ether, alkyl diphenyl ether, dialkyl diphenyl ether, pentaphenyl ether, tetraphenyl ether, mono Examples thereof include phenyl ether oils such as alkyl tetraphenyl ether and dialkyl tetraphenyl ether.

In the present invention, kinematic viscosity at 40 ° C. of one or more base oils selected from these mineral oils and synthetic oils are 5 to 40 mm ² / s, preferably 5 to 35 mm ² / s, more preferably 10 to 26 mm ² / s, more preferably from 10~22mm ² / s, even more preferably 10~18mm ² / s.
When the kinematic viscosity is less than 5 mm ² / s, it is difficult to suppress the phenomenon that the grease composition is oil-separated. On the other hand, when the kinematic viscosity exceeds 40 mm ² / s, it becomes difficult to supply oil to the sliding portion, and seizure is likely to occur in the aluminum-based member and the steel-based member in the sliding portion.
In the present invention, the kinematic viscosity at 40 ° C. of the base oil means a value measured according to JIS K2283.
The base oil used in the present invention may be a mixed base oil prepared by combining a high viscosity base oil and a low viscosity base oil and adjusting the kinematic viscosity to the above range.

  The blending amount of the base oil in the grease composition of the present invention is preferably 50% by mass or more, more preferably 60% by mass to 95% by mass with respect to the total amount of the grease composition.

<(A) Aliphatic diurea>
From the viewpoint of obtaining a grease composition excellent in the effect of suppressing poor lubrication when used for lubricating a sliding portion between an aluminum-based member and a steel-based member, the grease composition of the present invention is used as a thickener. (A) Aliphatic diurea is blended.
As the (A) aliphatic diurea, any compound having a chain hydrocarbon group at both ends and having two urea bonds can be used. From the above viewpoint, the aliphatic diurea is represented by the following general formula (a1). Are preferred.
^{R 1 -NHCONH-R 3 -NHCONH-} R 2 (a1)
(In formula (a1), R ¹ and R ² each independently represents a monovalent chain hydrocarbon group having 6 to 24 carbon atoms. R ³ is a divalent aromatic having 6 to 18 carbon atoms. Indicates a hydrocarbon group.)
In addition, R ¹ and R ² in the general formula (a1) may be the same group or different groups.

The monovalent chain hydrocarbon group having 6 to 24 carbon atoms represented by R ¹ and R ² in the general formula (a1) is a linear or branched saturated or unsaturated chain hydrocarbon group. Is included.
Examples of the monovalent chain hydrocarbon group include hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, An octadecyl group, an octadecenyl group, a nonadecyl group, an icodecyl group, etc. are mentioned, These may be linear or branched.
Examples of the monovalent unsaturated chain hydrocarbon group include a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, a dodecenyl group, a tridecenyl group, a tetradecenyl group, a pentadecenyl group, a hexadecenyl group, and an octadecenyl group. Group, nonadecenyl group, icocenyl group, oleyl group, geranyl group, farnesyl group, linoleyl group and the like.

  As the carbon number of the monovalent chain hydrocarbon group, a grease composition excellent in the effect of suppressing the occurrence of poor lubrication when used for lubrication of a sliding portion between an aluminum-based member and a steel-based member. From the viewpoint of obtaining, it is preferably 6 to 24, more preferably 6 to 18, still more preferably 6 to 12, and still more preferably 6 to 10.

As R ¹ and R ² in the general formula (a1), a grease composition that is excellent in suppressing the occurrence of poor lubrication when used for lubrication of a sliding portion between an aluminum-based member and a steel-based member. From the viewpoint of obtaining each independently, a monovalent chain hydrocarbon group having 6 to 24 carbon atoms is preferable, a monovalent chain hydrocarbon group having 6 to 10 carbon atoms is more preferable, a hexyl group, a heptyl group, An octyl group or a nonyl group is more preferable, and an octyl group is still more preferable.

Examples of the divalent aromatic hydrocarbon group having 6 to 18 carbon atoms represented by R ³ in the general formula (a1) include a phenylene group, a diphenylmethylene group, a diphenylethylene group, a diphenylpropylene group, a tolylene group, Examples include a benzylidene group.
Among these, a phenylene group, a diphenylmethylene group, a diphenylethylene group, or a diphenylpropylene group is preferable, and a diphenylmethylene group is more preferable.
As the carbon number of the divalent aromatic hydrocarbon group, a grease composition excellent in the effect of suppressing the occurrence of poor lubrication when used for lubricating the sliding portion between the aluminum-based member and the steel-based member. From the viewpoint of obtaining, it is preferably 6-18, more preferably 6-15, still more preferably 9-14.

  The diurea compound can be usually obtained by reacting a diisocyanate with a monoamine. The reaction is preferably performed by adding a base oil containing a monoamine to the base oil containing diisocyanate obtained by heating and dissolving in the base oil to be used while heating and stirring.

Examples of the diisocyanate include diisocyanates having a group corresponding to the divalent aromatic hydrocarbon group represented by R ³ in the general formula (a1).
Specific examples of the diisocyanate include diphenylene diisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate, and diphenylmethane diisocyanate is preferable.

Examples of the monoamine include amines having a group corresponding to the chain hydrocarbon group represented by R ¹ and R ² in the general formula (a1).
Specifically, monoamines having a chain hydrocarbon group include, for example, hexylamine, heptylamine, octylamine, nonylamine, decylamine, undecylamine, dodecylamine, tridecylamine, tetradecylamine, pentadecylamine, hexa Examples include decylamine, heptadecylamine, octadecylamine, octadecenylamine, nonadecylamine, icodecylamine and the like, which may be linear or branched.
Further, monoamines having unsaturated chain hydrocarbon groups include, for example, hexenylamine, heptenylamine, octenylamine, nonenylamine, decenylamine, dodecenylamine, tridecenylamine, tetradecenylamine, pentadecenylamine, hexadecenylamine, octadecenylamine, Examples include decenylamine, nonadecenylamine, icocenylamine, oleylamine, geranylamine, farnesylamine, and linoleylamine, which may be linear or branched.

Said (A) aliphatic diurea may be used individually or in combination of 2 or more types.
The blending amount of the component (A) is 5 to 40% by mass with respect to the total amount of the grease composition of the present invention, preferably 6 to 30% by mass, more preferably 7 to 25% by mass, and still more preferably. It is 8-20 mass%.
When the blending amount of the component (A) is less than 5% by mass, the resulting grease composition cannot obtain a desired consistency, and it becomes difficult to maintain the grease state.
On the other hand, when the blending amount of component (A) exceeds 40% by mass, the grease composition becomes too hard, leading to poor lubrication, and seizure is likely to occur in the aluminum-based member and the steel-based member in the sliding portion. .

In addition, the grease composition of the present invention may contain a thickener other than the component (A) as long as the effect of the present invention is not impaired, but does not contain a thickener other than the component (A). Is preferred.
Examples of thickeners other than component (A) include, for example, urea thickeners that do not fall under component (A), and saponification of carboxylic acids or esters thereof with hydroxides such as alkali metals, alkaline earth metals, and aluminum. Metal soap, various complex soaps such as lithium complex soap, and organically treated bentonite.

<(B) Dicarboxylic acid ester>
From the viewpoint of obtaining a grease composition excellent in the effect of suppressing poor lubrication when used for lubricating a sliding portion between an aluminum-based member and a steel-based member, the grease composition of the present invention is (B) dicarboxylic acid. Esters are blended.
Examples of (B) dicarboxylic acid esters include reaction products of dicarboxylic acids and alcohols, and compounds represented by the following general formula (b1) are preferred.
_{^{R 4 OOC- (R 6) n}} -COOR 5 (b1)
(In formula (b1), R ⁴ and R ⁵ each independently represent a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms.
R ⁶ represents a divalent hydrocarbon group having 1 to 20 carbon atoms. n represents 0 or 1, but n is preferably 1. )

Examples of the monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms represented by R ⁴ and R ⁵ in the general formula (b1) include, for example, a linear or branched alkyl group having 1 to 20 carbon atoms, Examples thereof include a straight chain or branched alkenyl group having 2 to 20 carbon atoms and a group having 3 to 20 carbon atoms in an alicyclic structure, and a straight chain or branched alkyl group having 1 to 20 carbon atoms is preferable.
In addition, as R < ⁴ > and R < ⁵ > in the said general formula (b1), although it may be the same group or a mutually different group, it is preferable that they are the same group.

Examples of the linear or branched alkyl group having 1 to 20 carbon atoms include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, Hexadecyl group etc. are mentioned, These may be linear or branched.
Carbon number of the alkyl group is preferably 1-20, more preferably 1-10, still more preferably 1-6, and still more preferably 1-3.

Examples of the linear or branched alkenyl group having 2 to 20 carbon atoms include a vinyl group, an allyl group, a butenyl group, a 1,3-butanedienyl group, a 1-methylvinyl group, a 1-methylallyl group, and a 1,1-dimethylallyl group. Group, 1,2-dimethylallyl group, 2-methylallyl group, hexenyl group, octenyl group, decenyl group, dodecenyl group, tetradecenyl group, hexadecenyl group, etc., which are linear or branched. May be.
The alkenyl group preferably has 2 to 20 carbon atoms, more preferably 2 to 10 carbon atoms, and still more preferably 2 to 5 carbon atoms.

Examples of the alicyclic structure-containing group having 3 to 20 carbon atoms include a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclooctyl group, and a cyclodecyl group, and the above-described alkyl group. And a cycloalkyl group.
The carbon number of the alicyclic structure-containing group is preferably 3 to 20, more preferably 4 to 12, and still more preferably 6 to 9.

Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms represented by R ⁶ in the general formula (b1) include a linear or branched alkylene group having 1 to 20 carbon atoms, and 2 to 20 carbon atoms. Examples thereof include a linear or branched alkenylene group, a divalent alicyclic structure-containing group having 5 to 20 ring carbon atoms, or a divalent aromatic ring structure-containing group having 6 to 20 ring carbon atoms. A linear or branched alkylene group having 1 to 20 carbon atoms and a linear or branched alkenylene group having 2 to 20 carbon atoms are preferable, and a linear or branched alkylene group having 1 to 20 carbon atoms is more preferable. preferable.

Examples of the linear or branched alkylene group having 1 to 20 carbon atoms include heptane diacids such as malonic acid, succinic acid, 2-methyl succinic acid, glutaric acid, adipic acid, and pimelic acid, and octane such as suberic acid. Nonanedioic acid such as diacid and azelaic acid, decanedioic acid such as sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid And linear or branched alkylene groups derived from saturated dicarboxylic acids such as icosanedioic acid and docosanedioic acid.
In addition, the above-mentioned saturated dicarboxylic acid further includes an arbitrary substituent (for example, an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group and a propyl group; a halogen such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom). Atoms, etc.).
The number of carbon atoms of the alkylene group is preferably 1-20, more preferably 3-20, and even more preferably 6-20.

Examples of the linear or branched alkenylene group having 2 to 20 carbon atoms include maleic acid, fumaric acid, itaconic acid, citraconic acid (cis-methylbutenedioic acid), mesaconic acid (trns-methylbutenedioic acid), and hexene. Derived from unsaturated dicarboxylic acids such as diacid, octenedioic acid, decenedioic acid, dodecenedioic acid, tetradecenedioic acid, hexadecenedioic acid, octadecenedioic acid, icosendioic acid, dococenedioic acid, 8,12-icosadienedioic acid, etc. And a straight chain or branched alkenylene group.
In addition, the above-mentioned unsaturated dicarboxylic acid may further include an arbitrary substituent (for example, an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group; a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. A halogen atom or the like).
As carbon number of the said alkenylene group, Preferably it is 2-20, More preferably, it is 3-20, More preferably, it is 6-20.

Examples of the divalent alicyclic structure-containing group having 5 to 20 ring carbon atoms include cyclopentane dicarboxylic acid, cyclopentene dicarboxylic acid, cyclohexane dicarboxylic acid, cyclohexene dicarboxylic acid, tetralin dicarboxylic acid, and decalin dicarboxylic acid. Examples include alicyclic structure-containing groups derived from alicyclic structure-containing dicarboxylic acids such as acids.
In addition, these alicyclic structure-containing groups may further have an arbitrary substituent on the ring (for example, an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, and a propyl group; a fluorine atom, a chlorine atom, a bromine atom, A halogen atom such as an iodine atom).
The ring-forming carbon number of the alicyclic structure-containing group is preferably 5 to 20, more preferably 6 to 20.

Examples of the divalent aromatic ring structure-containing group having 6 to 20 ring carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, naphthalene-2,3-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene- An aromatic ring structure-containing group derived from an aromatic ring structure-containing dicarboxylic acid such as 2,6-dicarboxylic acid.
In addition, these aromatic ring structure-containing groups may further have an arbitrary substituent on the ring (for example, an alkyl group having 1 to 3 carbon atoms such as a methyl group, an ethyl group, a propyl group; a fluorine atom, a chlorine atom, a bromine atom, A halogen atom such as an iodine atom).
The ring-forming carbon number of the aromatic ring structure-containing group is preferably 5-20, more preferably 6-20.

  When the total carbon number of the compound represented by the general formula (b1) is used for lubrication of the sliding portion between the aluminum-based member and the steel-based member, a grease composition excellent in the effect of suppressing poor lubrication is used. From the viewpoint of obtaining, it is preferably 6 to 34, more preferably 8 to 27, still more preferably 10 to 22, and still more preferably 12 to 22.

  Examples of the compound represented by the general formula (b1) used as the component (B) include dimethyl adipate, diethyl adipate, dipropyl adipate, dibutyl adipate, di-2-butyloctyl adipate, and adipic acid Diisotridecyl, di-2-pentylnonyl adipate; diisodecyl pimelate, di-2-butyloctyl pimelate; dimethyl suberate, diethyl suberate, dipropyl suberate, dibutyl suberate, diisodecyl suberate, di-2-suberate Propylheptyl, di-3,7-dimethyloctyl suberate, di-2-butyloctyl suberate; dimethyl azelate, diethyl azelate, dipropyl azelate, butyl at azelate, diisodecyl azelate, di-2-azelate Lopylheptyl, di-3,7-dimethyloctyl azelate, di-2-butyloctyl azelate; dimethyl sebacate, diethyl sebacate, dipropyl sebacate, dibutyl sebacate, diisononyl sebacate, di-3,5 sebacate 5-trimethylhexyl, diisodecyl sebacate, di-2-propylheptyl sebacate, di-3,7-dimethyloctyl sebacate, di-2-butyloctyl sebacate; dimethyl dodecanedioate, diethyl dodecanedioate, dodecanedi Dipropyl acid, dibutyl dodecanedioate, di-2-ethylhexyl dodecanedioate, diisooctyl dodecanedioate, diisononyl dodecanedioate, di-3,5,5-trimethylhexyl dodecanedioate, diisodecyl dodecanedioate, didecanedioic acid -3,7-dimethyl Octyl; dimethyl tetradecandioate, diethyl tetradecandioate, dipropyl tetradecandioate, dibutyl tetradecandioate, diisooctyl tetradecandioate, di-2-ethylhexyl tetradecandioate, diisononyl tetradecandioate, di-3,5 tetradecandioate 5-trimethylhexyl, tetradecandioic acid diisodecyl, tetradecandioic acid di-3,7-dimethyloctyl; cyclohexane-1,2-dicarboxylic acid dimethyl, cyclohexane-1,2-dicarboxylic acid diethyl, cyclohexane-1,2-dicarboxylic acid Dipropyl, cyclohexane-1,2-dicarboxylate dibutyl, cyclohexane-1,2-dicarboxylate diisodecyl, cyclohexane-1,2-dicarboxylate di-2-propylheptyl, cyclohexane-1,2 -Di-3,7-dimethyloctyl dicarboxylate, di-2-butyloctyl cyclohexane-1,2-dicarboxylate; cyclohexane-1,2-dicarboxylic acid in cyclohexane-1,2-dicarboxylate is cyclohexane-1 , 3-dicarboxylic acid or various dialkyl esters substituted with cyclohexane-1,4-dicarboxylic acid; dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, diisodecyl phthalate, di-2-propylheptyl phthalate, Di-3,7-dimethyloctyl phthalate, di-2-butyloctyl phthalate; dialkyl ester in which phthalic acid in said dialkyl phthalate is replaced by isophthalic acid or terephthalic acid; 8,13-dimethyl-8,12-icosadien Dimethyl diacid Like the.

  There is no restriction | limiting in particular in the manufacturing method of the compound represented by the said general formula (b1) used as (B) component by this invention, Esterification reaction using the said dicarboxylic acid and alcohols using a conventionally well-known method. By doing so, the target dicarboxylic acid ester can be obtained.

Said (B) dicarboxylic acid ester may be used individually or in combination of 2 or more types.
The blending amount of the component (B) is 0.1 to 5.0% by mass with respect to the total amount of the grease composition of the present invention, preferably 0.5 to 4.0% by mass, more preferably 1 It is 0.0-3.5 mass%, More preferably, it is 1.2-3.0 mass%.
When the blending amount of the component (B) is less than 0.1% by mass, the resulting grease composition is used to lubricate the sliding portion between the aluminum-based member and the steel-based member. The seizure is likely to occur in the system member and the steel system member. On the other hand, even if it exceeds 5% by mass, the effect of suppressing the occurrence of seizure is saturated and the wear may increase.

<(C) Rust preventive>
The grease composition of the present invention is preferably a composition obtained by further blending (C) a rust inhibitor.
(C) As the rust inhibitor, a rust inhibitor mixed in a general grease composition can be used, but (C-1) a carboxylic acid rust inhibitor, (C-2) an amine rust inhibitor. It is preferable to blend one or more selected from an agent and (C-3) a carboxylate-based rust inhibitor, (C-1) a carboxylic acid-based rust inhibitor, and (C-2) an amine-based rust inhibitor. And (C-3) it is more preferable to add all of the carboxylate-based rust inhibitor.

  (C-1) Examples of the carboxylic acid-based rust preventive agent include monocarboxylic acids, linear fatty acids such as lauric acid and stearic acid, and saturated carboxylic acids having a naphthene nucleus. Dicarboxylic acids include succinic acid and alkyl. Succinic acid derivatives such as succinic acid, alkyl succinic acid half ester, alkenyl succinic acid, alkenyl succinic acid half ester, succinimide, hydroxy fatty acid, mercapto fatty acid, sarcosine derivative, and oxidized wax such as oxide of wax and petrolatum, etc. Can be mentioned.

  Examples of (C-2) amine-based rust preventives include alkoxyphenylamine, amine salts of carboxylic acids mentioned as component (C-1), partial amides of dibasic carboxylic acids, and the like.

Examples of (C-3) carboxylate-based rust preventives include fatty acid metal salts, naphthenic acid metal salts, abietic acid metal salts, lanolin fatty acid metal salts, alkenyl succinic acid metal salts, and amino acid derivatives. A metal salt etc. are mentioned.
In addition, as a metal element in these metal salts, cobalt, manganese, zinc, aluminum, calcium, barium, lithium, magnesium, copper etc. are mentioned, for example.

  The blending amount of the component (C) is preferably 0.1 to 13.0% by mass, more preferably 0.3 to 10.0% by mass, and still more preferably 1 with respect to the total amount of the grease composition of the present invention. It is 0.0-8.0 mass%, More preferably, it is 1.5-5.0 mass%.

<(D) Antioxidant>
The grease composition of the present invention is preferably a composition obtained by further blending (D) an antioxidant.
Examples of (D) antioxidants include amine-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, and zinc dithiophosphate.

  Examples of amine antioxidants include monoalkyl diphenylamine compounds such as monooctyl diphenylamine and monononyl diphenylamine, 4,4′-dibutyldiphenylamine, 4,4′-dipentyldiphenylamine, 4,4′-dihexyldiphenylamine, 4 , 4′-diheptyldiphenylamine, 4,4′-dioctyldiphenylamine, dialkyldiphenylamine compounds such as 4,4′-dinonyldiphenylamine; polyalkyls such as tetrabutyldiphenylamine, tetrahexyldiphenylamine, tetraoctyldiphenylamine, tetranonyldiphenylamine Diphenylamine compounds; α-naphthylamine, phenyl-α-naphthylamine, butylphenyl-α-naphthylamine, pentylphenyl-α- Fuchiruamin, hexylphenyl -α- naphthylamine, heptylphenyl -α- naphthylamine, octylphenyl -α- naphthylamine, naphthylamine-based compounds such as nonylphenyl -α- naphthylamine.

  Examples of phenolic antioxidants include p-tert-butyl-phenyl salicylate, 2,6-di-tert-butyl-p-phenylphenol, and 2,2′-methylenebis (4-methyl-6-tert-octylphenol). ), 4,4′-butylidenebis-6-tert-butyl-m-cresol, tetrakis [methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate] methane, , 3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, n-octadecyl-β- (4′-hydroxy-3 ′, 5′- Di-tert-butylphenyl) propionate, 2-n-octyl-thio-4,6-di (4′-hydroxy-3 ′, 5′-di-te) t-butyl) phenoxy-1,3,5-triazine, 4,4′-thiobis (6-tert-butyl-m-cresol), 2- (2′-hydroxy-3′-tert-butyl-5′-) Methylphenyl) -5-chlorobenzotriazole and the like.

In addition, you may use said (D) antioxidant individually or in combination of 2 or more types.
The amount of component (D) is preferably 0.05 to 10% by mass, more preferably 0.1 to 7% by mass, and still more preferably 0.2 to 5%, based on the total amount of the grease composition of the present invention. The mass% is still more preferably 0.3 to 2 mass%.
(D) If the compounding quantity of a component is 0.05 mass% or more, it can be set as the grease composition which has favorable antioxidant performance. On the other hand, if the blending amount of the component (D) is 10% by mass or less, the lubricity of the resulting grease composition can be maintained well.

<Other additives>
The grease composition of the present invention may be blended with other additives blended in a general grease composition as long as the effects of the present invention are not impaired.
Examples of other additives include a lubricity improver, a cleaning dispersant, a corrosion inhibitor, an antifoaming agent, an extreme pressure agent, and a metal deactivator.

Examples of the lubricity improver include sulfur compounds (sulfurized oils and fats, sulfurized olefins, polysulfide, sulfurized mineral oil, thiophosphoric acids such as triphenylphosphorothioate, thiocarbamic acids, thioterpenes, dialkylthiodipyropionates), phosphoric acid, and the like. Examples thereof include esters and phosphites (tricresyl phosphate, triphenyl phosphite, etc.).
Examples of the cleaning dispersant include succinimide and boron succinimide.
Examples of the corrosion inhibitor include benzotriazole compounds and thiazole compounds.
Examples of antifoaming agents include silicone compounds and fluorinated silicone compounds.
Examples of the extreme pressure agent include phosphorus compounds, zinc dithiophosphate, and organic molybdenum.
Examples of the metal deactivator include benzotriazole.

  In addition, what is necessary is just to select suitably the compounding quantity of each of these additives according to the objective, Preferably it is 0-20 mass% with respect to the whole quantity of the grease composition of this invention, More preferably, it is 0-10. It is 0 mass%, More preferably, it is 0-5 mass%.

The grease composition of the present invention can contain a thickener. The thickener increases the viscosity of the base oil as necessary, and is added to adjust the base oil containing the thickener to an appropriate kinematic viscosity.
Examples of the thickener include polymethacrylate (PMA), olefin copolymer (OCP), polyalkylstyrene (PAS), styrene-diene copolymer (SCP), and the like.
The blending amount of the thickener may be appropriately selected according to the purpose, but is preferably 0 to 20% by mass, more preferably 0 to 10% by mass, and still more preferably based on the total amount of the grease composition of the present invention. Is 0 to 5 mass%, more preferably 0 to 2 mass%.

The kinematic viscosity at 40 ° C. of the composition obtained by removing the thickener from the grease composition of the present invention is preferably 5 to 40 mm ² / s even when the above thickener is blended.
That is, the kinematic viscosity at 40 ° C. of the composition obtained by removing the thickener from the grease composition of the present invention is preferably 10 to 40 mm ² / s, more preferably 10 to 26 mm ² / s, and still more preferably 10 to 10 mm. 22 mm ² / s, even more preferably from 10~18mm ² / s.

  The method for preparing the grease according to the present invention is not particularly limited. For example, the base oil is blended with a predetermined proportion of the component (A) and, if desired, a thickener or a thickener other than the component (A). The mixture is heated to homogenization (preferably 100 to 200 ° C.), homogenized, and then cooled, and when it reaches a predetermined temperature (preferably 50 to 95 ° C.), a predetermined amount of component (B) and various additives are blended. The method of preparing by this is mentioned.

  The grease composition of the present invention has an excellent effect of suppressing the occurrence of poor lubrication when used for lubrication of a sliding portion between an aluminum-based member and a steel-based member. It can be suitably used as a lubricant for sliding parts made of aluminum-based members and steel-based members such as industrial machines. In particular, it can be suitably used for a lubrication portion having a large contact area where a poor lubrication state is likely to occur, and a gear mechanism such as a worm gear or a hypoid gear in which a large amount of slip occurs in the gear mechanism.

Examples of the aluminum-based member include, for example, an alloy of one or more metals selected from aluminum, copper, manganese, silicon, magnesium, zinc, nickel, and the like, such as 1000s, 2000s, and 3000s. Examples include, but are not limited to, 4000 series, 5000 series, 6000 series, 7000 series, and 8000 series aluminum-based members.
Examples of the steel-based member include carbon steel, alloy steel, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel, manganese steel and the like, which are generally called steel, and cast iron and soft iron. It is not limited to these.

  When the grease composition of the present invention is used for lubrication of the sliding portion between the aluminum-based member and the steel-based member in the evaluation test described in the Examples, the sliding-side aluminum-based member and the steel-based member are used. The time until seizure occurs is preferably 2000 seconds or more, more preferably 2300 seconds or more, and further preferably 2500 seconds or more.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Various characteristics were determined according to the following methods.

(1) 40 ° C. kinematic viscosity of “base oil” and “composition obtained by removing thickener from grease composition” Measured according to JIS K2283.

(2) Time until seizure occurred Using a tester compliant with ASTM D2670 and D3223 (Farex P / V test), the time until seizure of the sliding part member was measured and prepared. The suppression effect of the occurrence of poor lubrication of the grease composition was evaluated. The aluminum member “A2014” was used as the pin member of the test machine, and the steel member “AISI C-1137” was used as the block member.
Then, apply 10 mg of the grease composition prepared on the pin, set the rotation speed to 290 rpm, load 250 N, test at room temperature (25 ° C.), and seizure occurs in the sliding part between the pin and the block. The time to do was measured. It can be said that the longer the time until seizure occurs, the more excellent the grease composition is in suppressing the occurrence of poor lubrication at the sliding portion between the aluminum-based member and the steel-based member.
If the time until seizure occurs in this test is 2000 seconds or more, the hypoid gear rotation speed is 10 ⁵ revolutions with a gear mechanism composed of a hypoid gear made of aluminum and a pinion gear made of steel. It can be said that the level of lubrication can be suppressed. In general, the number of repetitions is 10 ^5, which is a measure for high cycle fatigue, and if there is no seizure, the level is practically acceptable.

Examples 1-4, Comparative Examples 1-5
“Diphenylmethane-4,4′-diisocyanate (MDI)”, which is a raw material for the thickener, was dissolved by heating in 2/3 of the base oil of the type shown in Table 1. On the other hand, “octylamine” having a molar amount twice that of the above MDI was dissolved in the remaining 1/3 base oil by heating.
Then, the above-mentioned “base oil containing diphenylmethane-4,4′-diisocyanate” is charged into a grease production kettle, and the above-mentioned “base oil containing octylamine” is added thereto while stirring vigorously at 50 to 60 ° C. Was gradually added and heated. When the temperature reached 160 ° C., the temperature was maintained for 1 hour. Note that the blending amount of the thickener was adjusted to 11.5% by mass with respect to the total amount of the grease composition, and therefore the blending amount of the raw material compound serving as the thickener was also prepared.
Next, after cooling to 80 ° C. at 50 ° C./h, additives of the types and blending amounts shown in Table 1 (but not added in Comparative Example 3), a rust inhibitor and an antioxidant were added. Furthermore, after naturally cooling to room temperature (25 degreeC), the grease composition was obtained by performing a finishing process using a 3 roll apparatus.

Comparative Examples 6-7
“12-hydroxystearic acid” as a thickener raw material is mixed with the types of base oils shown in Table 1, heated to about 90 ° C., dissolved in the base oil, and then an aqueous lithium hydroxide solution. Was added and allowed to react. Note that the blending amount of the thickener was adjusted to 11.5% by mass with respect to the total amount of the grease composition, and therefore the blending amount of the raw material compound serving as the thickener was also prepared.
Next, after the reaction was heated to 220 ° C., the soap was dissolved in the reaction oil and then cooled to room temperature (25 ° C.) as it was, and the additives of the types and amounts shown in Table 1 (however, in Comparative Example 7) After addition of a rust inhibitor and an antioxidant, a grease composition was obtained by uniformly dispersing with a three-roll mill.

Each component used in the Examples and Comparative Examples is as follows.
<Base oil>
Base oil I: Poly α-olefin adjusted so that the kinematic viscosity at 40 ° C. is 15 mm ² / s Base oil II: Poly α-olefin adjusted so that the kinematic viscosity at 40 ° C. is 30 mm ² / s .
Base oil III: polyα-olefin adjusted so that the kinematic viscosity at 40 ° C. is 50 mm ² / s.
Base oil IV: polyalphaolefin adjusted so that the kinematic viscosity at 40 ° C. is 100 mm ² / s.

<Thickener>
Reaction product of octylamine and MDI: R ¹ and R ² in the general formula (a1) correspond to an aliphatic diurea in which R ³ is an octyl group and R ³ is a diphenylmethylene group.
・ Reaction product of 12-hydroxystearic acid and lithium hydroxide

<Additives>
-Dimethyl dodecanedioate: Corresponding to a dicarboxylic acid ester in which R ⁴ and R ⁵ in the general formula (b1) are methyl groups and R ⁶ is an alkylene group derived from dodecanedioic acid (— (CH ₂ ) ₁₀ —) To do.
-Dimethyl 8,13-dimethyl-8,12-icosadiendioic acid: R ⁴ and R ⁵ in the general formula (b1) are methyl groups, and R ⁶ is 8,13-dimethyl-8,12-icosadienedioic acid. It corresponds to a dicarboxylic acid ester which is an alkenylene group derived from the origin.
・ Methyl oleate ・ Zn-DTP (zinc dialkyldithiophosphate)
<Rust preventive>
Alkenyl succinic acid half ester: a rust inhibitor corresponding to the component (C-1).
Carboxylic acid amine salt: A rust inhibitor corresponding to the component (C-2).
-Zinc naphthenate: a rust inhibitor corresponding to the component (C-3).
In addition, as described in Table 1, in each grease composition of Examples 1 to 4 and Comparative Examples 1 to 7, “alkenyl succinic acid half ester”, “carboxylic acid amine salt”, and “ A total of 3.5 parts by mass of three types of “zinc naphthenate” is blended.
<Antioxidant>
Dioctyl diphenylamine: an amine-based antioxidant.
2,6-di-tert-butyl-p-cresol: a phenolic antioxidant.

  According to Table 1, the grease compositions prepared in Examples 1 to 4 were used for lubrication of the sliding portion between the aluminum-based member and the steel-based member as compared with the grease compositions prepared in Comparative Examples 1-7. When this occurs, it can be seen that the time until the occurrence of seizure is long and the effect of suppressing the occurrence of poor lubrication is excellent.

Claims (6)

A base oil composed of one or more selected from mineral oils and synthetic oils other than dicarboxylic acid esters and having a kinematic viscosity at 40 ° C. of 5 to 40 mm ² / s, (A) an aliphatic diurea, and (B) a dicarboxylic acid A grease composition comprising an ester and used for lubrication between an aluminum-based member and a steel-based member,
The grease composition, wherein the blending amount of the component (A) is 5 to 40% by mass and the blending amount of the component (B) is 0.1 to 5.0% by mass with respect to the total amount of the grease composition.   Further, as (C) a rust inhibitor, one selected from (C-1) a carboxylic acid rust inhibitor, (C-2) an amine rust inhibitor, and (C-3) a carboxylate rust inhibitor. The grease composition according to claim 1, comprising the above.   The grease composition according to claim 1 or 2, further comprising (D) an antioxidant. (A) The grease composition in any one of Claims 1-3 whose aliphatic diurea is a compound represented by the following general formula (a1).
^{R 1 -NHCONH-R 3 -NHCONH-} R 2 (a1)
(In formula (a1), R ¹ and R ² each independently represents a monovalent chain hydrocarbon group having 6 to 24 carbon atoms. R ³ is a divalent aromatic having 6 to 18 carbon atoms. Indicates a hydrocarbon group.) The grease composition according to claim 4, wherein R ¹ and R ² in the general formula (a1) are each independently a monovalent chain hydrocarbon group having 6 to 10 carbon atoms. (B) The grease composition in any one of Claims 1-5 whose dicarboxylic acid ester is a compound represented by the following general formula (b1).
_{^{R 4 OOC- (R 6) n}} -COOR 5 (b1)
(In formula (b1), R ⁴ and R ⁵ each independently represents a monovalent aliphatic hydrocarbon group having 1 to 20 carbon atoms. R ⁶ is a divalent hydrocarbon having 1 to 20 carbon atoms. Represents a group, and n represents 0 or 1.)