JP5826626B2 - Grease composition - Google Patents

Description

  The present invention relates to a grease composition, and more particularly to a grease composition having high wear resistance.

  The sliding and rotating parts of the machine require some kind of lubrication base material, but most of them use lubricating oil or grease. Among them, grease lubrication can simplify the seal structure and make the device compact and compact. There are very many machines that use this method. For example, various rolling bearings that support rotating bodies, plain bearings, ball joints, links or chains, gears, wires, and sliding parts of crane booms, etc. are extremely wide, and the required quality has been improved year by year. Long life and maintenance-free are common issues for all machines. In recent years, fatigue breakage and damage of materials have been extremely reduced due to advances in mechanical technology, material technology and processing accuracy, and the life of machines has been greatly influenced by the performance of lubricating oil and grease. Therefore, it is extremely important to improve the lubricity of grease and solve these problems because it can greatly contribute to the improvement of machine quality and reliability.

  Here, concretely, there are the following two cases in which the lubrication performance of the grease decreases at the rotating part and sliding part of the machine and the machine life is exhausted. First, when used at high temperatures, the grease is oxidized, and the grease structure is destroyed due to the solidification of the grease due to oil evaporation or thermal polymerization or the generation of organic acids and aldehydes. When used at low speed and high load, or on machine sliding surfaces where sliding friction occurs frequently at high speeds, boundary lubrication is likely to occur, and the grease lubrication film becomes very thin. In some cases, it increases and leads to damage such as metal peeling or seizure.

  Means for solving the first case include a method of extending the mechanical life by effectively blending an appropriate antioxidant with grease (see Patent Document 1), thermal structural change and chemical change. There is a technology that uses a small amount of thickener and base oil as a raw material for grease to improve the overall function of the grease, thereby extending the machine life. One of the thermally stable thickeners is urea grease, and in recent years, technical development using this thickener has been frequently carried out. (See Patent Document 2) Urea grease is used in a wide range of fields because it has a higher dropping point than grease containing a thickening agent of lithium soap, and is excellent in thermal stability, wear resistance and lubricity. It is like that. For example, in the automotive industry, various automotive parts such as CVJ (constant velocity joints), electric power steering, alternator bearings and wheel bearings have increasingly higher requirements for heat resistance, wear resistance and friction characteristics, and the superiority of urea grease In many cases, performance and additive technology are applied.

  In addition, since automobiles are used all over the world, grease used for automobile parts is extremely cold at around -40 ° C and high temperatures over 100 ° C (radiation heat from the engine room + radiant heat from the road surface). Designed and manufactured with constant use in mind, low torque torque can be obtained over a wide temperature range from low temperature to high temperature, and the oil film is not cut off due to viscosity drop at high temperatures, resulting in a vehicle lifespan. There is a need for long-life greases that meet these requirements.

  Technology to improve low temperature characteristics by blending a methacrylate polymer with a synthetic hydrocarbon oil (polyalpha-olefin), ester base oil or glycol base oil with excellent low temperature fluidity in grease base oil However, there is a need for further improvements in quality and performance. (See Patent Document 3)

  Means for solving the second case include a method of suppressing metal contact by increasing the base oil viscosity of the grease, or by adding a thickener such as a polymer to thicken the lubricating oil film (see Patent Document 4), Load-bearing additives such as wear agents, extreme pressure agents, or solid lubricants are blended into grease, and the surface is protected by forming a film or solid film between sliding surfaces by the chemical or physical action of the additive. Is the method. However, depending on the type of additive, there are many additives that change the grease structure or affect the components of the machine. For example, thiophosphates having a high acid value have a drawback that they easily react with free alkalis in soap greases, and sulfurized olefin additives may cause the urea grease to cure over time. Furthermore, additives with strong chemical activity have many problems such as discoloration and corrosion of metals, or reducing the strength of sealing materials such as rubbers such as nitrile, acrylic, and urethane.

  Therefore, for grease lubrication, it is necessary to maintain an appropriate oil film and form an adsorption film on the lubricated sliding surface without adversely affecting the grease structure. It is extremely effective in securing and extending machine life.

Patent No. 2085136 Japanese Patent No. 4769456 JP 2006-77119 A JP2008-69282 Japanese Patent No. 3833756 JP-A-2-18497

  An object of the present invention is to provide a grease composition having high wear resistance.

  Under such circumstances, the inventors have intensively studied, and as a result, have found that by using a poly (meth) acrylate derivative containing a hydroxyl group, it is possible to improve the wear resistance of the grease and solve the problem. .

  The present invention is a grease composition containing a base oil and a thickener, wherein a poly (meth) acrylate derivative containing a hydroxyl group is used as an additive.

  The grease composition according to the present invention has an effect of having higher wear resistance as compared with the conventional grease composition.

  Hereinafter, although one aspect of the present invention will be described in detail, the technical scope of the present invention is not limited to the one aspect.

  The grease composition of this embodiment contains “base oil”, “thickener” and “additive” as essential components. Hereinafter, each component contained in the grease composition, the amount (mixing amount) of each component in the grease composition, the manufacturing method of the grease composition, the properties of the grease composition, and the use of the grease composition will be described in order.

≪Grease composition (component) ≫
[Base oil]
The base oil used for the grease composition of this embodiment is not particularly limited. For example, mineral oils, synthetic oils, animal and vegetable oils, and mixed oils thereof used in ordinary grease compositions can be appropriately used. As a specific example, base oils belonging to Group I, Group II, Group III, Group IV, etc. in the API (American Petroleum Institute) base oil category may be used alone or as a mixture.

  For Group I base oils, for example, paraffin obtained by applying a suitable combination of solvent refining, hydrorefining, dewaxing, etc. to lubricating oil fractions obtained by atmospheric distillation of crude oil There are mineral oils. For Group II base oils, for example, paraffinic mineral oil obtained by applying a suitable combination of hydrocracking, dewaxing and other refining means to a lubricating oil fraction obtained by atmospheric distillation of crude oil There is. Group II base oils refined by hydrorefining methods such as the Gulf Company method have a total sulfur content of less than 10 ppm and an aroma content of 5% or less, and can be suitably used in the present invention. Group III base oils and Group II plus base oils include, for example, paraffinic mineral oils produced by advanced hydrorefining and dewaxing processes for lubricating oil fractions obtained by atmospheric distillation of crude oil. There are base oils refined by the ISODEWAX process for converting and dewaxing the produced wax to isoparaffin, and base oils refined by the mobile WAX isomerization process, and these can also be suitably used in this embodiment.

  Synthetic oils include, for example, polyolefins, dibasic acid diesters such as dioctyl sebacate, polyol esters, alkylbenzenes, alkylnaphthalenes, esters, polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers, polyphenyls. Examples include ether, dialkyldiphenyl ether, fluorine-containing compounds (perfluoropolyether, fluorinated polyolefin, etc.), silicone and the like. The polyolefin includes polymers of various olefins or hydrides thereof. Any olefin may be used, and examples thereof include ethylene, propylene, butene, and α-olefin having 5 or more carbon atoms. In the production of polyolefin, one of the above olefins may be used alone, or two or more may be used in combination. Polyolefins called poly-α-olefin (PAO) synthetic oils are particularly preferred from the viewpoint of low temperature fluidity and improved lubricity at low temperatures, and are Group IV base oils. Since the poly-α-olefin synthetic oil has a high viscosity index, there is little decrease in viscosity at a high temperature, and the ability to retain an oil film is high, and at low temperatures, the viscosity does not become too high and appropriate fluidity is maintained. Therefore, there is little decrease in lubricity. This excellent low-temperature property is an action that works extremely effectively when used as a grease base oil. For example, if lubricating oil that loses fluidity is used as a base oil for grease, the viscosity is extremely high at low temperatures, and the grease loses fluidity completely. However, grease containing a base oil with excellent low-temperature fluidity, such as poly-α-olefin synthetic oil, does not lose fluidity, so it can supply an appropriate amount of lubricating oil to the sliding surface. The lubrication function is maintained and wear can be suppressed.

  Oil obtained by GTL (Gas Liquid) synthesized by the Fischer-Tropsch method of natural gas liquid fuel technology has extremely low sulfur and aromatic content compared to mineral base oil refined from crude oil. Since it is low and has a very high paraffin constituent ratio, it has excellent oxidation stability and very low evaporation loss. Therefore, it can be suitably used as the base oil of this embodiment.

[Thickener]
The thickener used as an essential component in this embodiment is not particularly limited, and may be one used in a normal grease composition. For example, urea thickeners, metal soaps, composite soaps, organic bentonites, silicas and the like can be mentioned. Here, examples of the urea type include aliphatic diurea, alicyclic diurea, aromatic diurea, triurea, tetraurea, and urea urethane. Examples of the metal soap include 12-hydroxy lithium stearate, lithium stearate, 12-hydroxy calcium stearate, calcium stearate, lithium complex, calcium complex, barium complex, aluminum complex, lithium calcium mixed soap and the like. The organic bentonite is montmorillonite treated with a quaternary ammonium salt, and the silica is ultrafine silica powder produced by a gas phase reaction or the surface thereof treated with a lower alcohol such as methanol. Can be mentioned. Other examples include sulfonate complexes, polytetrafluoroethylene, and tricalcium phosphate.

  Of these, preferred thickeners are urea compounds produced by reaction with isocyanates and primary amines. For example, it may be diurea, triurea, tetraurea, pentaurea or hexaurea, may be aliphatic urea, alicyclic urea or aromatic urea, or may be urea having another group (for example, urethane group) (for example, urea urethane).

  Here, for example, the diurea thickener is obtained, for example, by reacting 1 mol of diisocyanate with 2 mol of primary monoamine. The tetraurea thickener is obtained, for example, by reacting 2 mol of diisocyanate, 1 mol of primary diamine and 2 mol of primary monoamine. The triurea monourethane thickener is obtained, for example, by reacting 2 moles of diisocyanate with 1 mole of primary diamine and 1 mole of primary monoamine with 1 mole of monoalcohol. Hereinafter, examples of various raw materials used when synthesizing a urea compound will be given.

  Examples of the diisocyanate include aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate. More specific examples include 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), naphthalene diisocyanate, p-phenylene diisocyanate, trans-1,4-cyclohexane diisocyanate (CHDI), 1,3- Bis- (isocyanatomethyl-benzene), 4,4'-dicyclohexylmethane diisocyanate (H12MDI), 1,3-bis- (isocyanatomethyl) -cyclohexane (H6XDI), hexamethylene diisocyanate (HDI), 3-isocyanato Methyl-3,3,5'-trimethylcyclohexyl isocyanate (IPDI), phenylene diisocyanate, m-tetramethylxylene diisocyanate (m-TMXDI), p-tetramethylxylene dii Cyanate (p-TMXDI) and the like, and in particular, 4,4'-diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), trans-1,4-cyclohexane diisocyanate (CHDI), 4,4'-dicyclohexylmethane diisocyanate ( H12MDI).

  Primary monoamines include aliphatic, alicyclic or aromatic monoamines. Here, as the aliphatic amine, a C8 to C24 saturated or unsaturated aliphatic amine, which is branched or linear, is used, and a linear one is particularly preferable. Specific examples include octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like.

  Primary diamines include aliphatic, alicyclic or aromatic diamines. For example, C2-C12 diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, hexamethylenediamine, octamethylenediamine, decamethylenediamine and other alicyclic diamines such as diaminocyclohexane, and phenylenediamine, Examples thereof include aromatic diamines such as benzidine, diaminostilbene, and tolidine.

  Monoalcohols include aliphatic, alicyclic or aromatic alcohols. Here, as the aliphatic alcohol, a C8-C24 saturated or unsaturated aliphatic alcohol, which is branched or linear, is used, and a linear alcohol is particularly preferable. Specifically, octyl alcohol, decyl alcohol, dodecyl alcohol, tetradecyl alcohol, hexadecyl alcohol, octadecyl alcohol, oleyl alcohol, etc., alicyclic alcohol, cyclohexyl alcohol, etc., aromatic alcohol, benzyl alcohol, Examples include salicyl alcohol, phenethyl alcohol, cinnamyl alcohol, hydrocinnamyl alcohol, and the like.

（式中、Ｒ^１及びＲ^３は炭素数８〜１２の脂肪族炭化水素基を示し、Ｒ^２は炭素数６〜１５の２価の芳香族基を示す。）で表される化合物である。ここで、Ｒ^１及びＲ^３は、相互に独立して、炭素数８のオクチル基又は炭素数１２のラウリル基であることが好適である。また、Ｒ^２はジフェニルメタン基であることが好適である。より好適な態様は、Ｒ^２はジフェニルメタン基であって、且つ、（１）Ｒ^１及びＲ^３が炭素数８のオクチル基である化合物、（２−１）Ｒ^１及びＲ^３が炭素数８のオクチル基である化合物と、Ｒ^１及びＲ^３が炭素数１２のラウリル基である化合物と、の混合物、（２−２）Ｒ^１及びＲ^３の一方が炭素数８のオクチル基であり、Ｒ^１及びＲ^３の他方が炭素数１２のラウリル基である化合物、（２−３）（２−１）の化合物の一方又は両方と、（２−２）の化合物と、の混合物、である。これらの内、（２−１）〜（２−３）が特に好適である。 Of these, alkyldiurea is preferable, and more preferable is general formula (I):

(Wherein R ¹ and R ³ represent an aliphatic hydrocarbon group having 8 to 12 carbon atoms, and R ² represents a divalent aromatic group having 6 to 15 carbon atoms). . Here, R ¹ and R ³ are preferably each independently an octyl group having 8 carbon atoms or a lauryl group having 12 carbon atoms. R ² is preferably a diphenylmethane group. More preferred embodiment, ^{R 2} is a diphenylmethane group and, (1) Compound ^{R 1} and ^{R 3} are octyl group having 8 carbon atoms, (2-1) ^{R 1} and ^{R 3} to 8 carbon atoms (2-2) ^one of R ¹ and R ³ is an octyl group having 8 carbon atoms, a mixture of a compound that is an octyl group of R ² and a compound in which R ¹ and R ³ are 12 lauryl groups, A compound in which the other of R ¹ and R ³ is a lauryl group having 12 carbon atoms, (2-3) one or both of the compounds of (2-1) and the compound of (2-2) . Of these, (2-1) to (2-3) are particularly suitable.

(Other thickeners)
In the grease composition of the present embodiment, other thickeners can be used in combination with the main thickener {for example, the above urea compound (for example, alkyldiurea)}. For example, when a urea compound is used as the main thickener, these other thickeners include tribasic calcium phosphate, alkali metal soap, alkali metal composite soap, alkaline earth metal soap, alkaline earth composite soap, alkaline Examples thereof include metal sulfonates, alkaline earth metal sulfonates, other metal soaps, terephthalate metal salts, silica (silicon oxide) such as clay and silica airgel, and fluorine resins such as polytetrafluoroethylene. Species or two or more can be used in combination. In addition to these, any of those that can impart a sticky effect can be used.

[Additive]
The additive used as an essential component in this embodiment is a poly (meth) acrylate containing a hydroxyl group. The poly (meth) acrylate containing a hydroxyl group is a copolymer, and an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms and a hydroxyl group-containing vinyl monomer are essential constituent monomers. It is a copolymer.

As the alkyl (meth) acrylate (a) having an alkyl group having 1 to 20 carbon atoms, specifically,
(A1) Alkyl (meth) acrylate having an alkyl group having 1 to 4 carbon atoms:
For example, methyl (meth) acrylate, ethyl (meth) acrylate, n- or iso-propyl (meth) acrylate, n-, iso- or sec-butyl (meth) acrylate (a2) an alkyl group having 8 to 20 carbon atoms. Alkyl (meth) acrylate having:
For example, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-decyl (meth) acrylate, n-isodecyl (meth) acrylate, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, 2-methylundecyl (meth) acrylate, n-tridecyl (meth) acrylate, 2-methyldodecyl (meth) acrylate, n-tetradecyl (meth) acrylate, 2-methyltridecyl (meth) acrylate, n-pentadecyl (meta ) Acrylate, 2-methyltetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate, n-octadecyl (meth) acrylate, n-eicosyl (meth) acrylate, n-docosyl (meth) acrylate, dovanol 23 [ Methacrylate of Mitsubishi Chemical methacrylate oxo alcohol mixture on the Co., Ltd. 12 carbon atoms / carbon atoms 13, Dobanol 45 [carbons manufactured by Mitsubishi Chemical Corporation 13 / number 14 oxo alcohol mixture of carbon,
(A3) Alkyl (meth) acrylate having an alkyl group having 5 to 7 carbon atoms:
Examples thereof include n-pentyl (meth) acrylate and n-hexyl (meth) acrylate.

  Of the above (a1) to (a3), preferred are the substances belonging to (a1) and (a2), and more preferred is the substance (a2). Of the above (a2), those having 10 to 20 carbon atoms, more preferably 12 to 14 carbon atoms, are preferred from the viewpoint of solubility in base oil.

The hydroxyl group-containing vinyl monomer (b) constituting the copolymer with the alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms described above is one or more (preferably 1 or 2) in the molecule. ) -Containing vinyl monomer. As a specific example,
(B1) Hydroxyalkyl (C2-6) (meth) acrylate:
For example, 2-hydroxyethyl (meth) acrylate, 2 or 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1-methyl-2-hydroxyethyl (meth) acrylate, etc.
(B2) Mono- or di-hydroxyalkyl (C1-C4) substituted (meth) acrylamide:
For example, N, N-dihydroxymethyl (meth) acrylamide, N, N-dihydroxypropyl (meth) acrylamide, N, N-di-2-hydroxybutyl (meth) acrylamide, etc. (b3) vinyl alcohol (hydrolysis of vinyl acetate units) Formed by decomposition),
(B4) Alkenol having 3 to 12 carbon atoms:
For example, (meth) allyl alcohol, crotyl alcohol, isocrotyl alcohol, 1-octenol, 1-undecenol, etc.
(B5) Alkene diol having 4 to 12 carbon atoms:
For example, 1-buten-3-ol, 2-buten-1-ol, 2-butene-1,4-diol, etc.
(B6) Hydroxyalkyl (C1-6) alkenyl (C3-10) ether: For example, 2-hydroxyethylpropenyl ether, etc.
(B7) Hydroxyl group-containing aromatic monomer: For example, o-, m-, or p-hydroxystyrene (b8) Polyhydric (3 to 8 valent) alcohol:
For example, alkane polyol, intramolecular or intermolecular dehydrate, alkenyl (3 to 10 carbon atoms) ether or (meth) acrylate (eg, glycerin, pentaerythritol, sorbitol, sorbitan, diglycerin, sucrose) (for example, Sucrose (meth) allyl ether), etc.
(B9) Vinyl monomer containing polyoxyalkylene chain and hydroxyl group:
For example, polyoxyalkylene glycol (alkylene group having 2 to 4 carbon atoms, polymerization degree 2 to 50) or polyoxyalkylene polyol {polyoxyalkylene ether of 3 to 8 valent alcohol (alkyl group having 2 to 4 carbon atoms, Mono (meth) acrylate or mono (meth) allyl ether {for example, polyethylene glycol (degree of polymerization 2-9) mono (meth) acrylate, polypropylene glycol (degree of polymerization 2-12) mono (meta) ) Acrylate, polyethylene glycol (degree of polymerization 2-30) mono (meth) allyl ether} and the like.

Other monomers (a) and (b) can be copolymerized with the poly (meth) acrylate copolymer containing the hydroxyl group, and as such a monomer, a nitrogen atom-containing monomer ( c). In particular,
(C1) Nitro group-containing monomer: For example, 4-nitrostyrene
(C2) A primary to tertiary amino group-containing vinyl monomer:
(C2-1) Primary amino group-containing vinyl monomer; for example, alkenylamine having 3 to 6 carbon atoms [(meth) allylamine, crotylamine, etc.], aminoalkyl (2 to 6 carbon atoms) (meth) acrylate [amino Ethyl (meth) acrylate, etc.]
(C2-2) Secondary amino group-containing vinyl monomer; For example, alkyl (1 to 6 carbon atoms) aminoalkyl (2 to 6 carbon atoms) (meth) acrylate [t-butylaminoethyl methacrylate, methylaminoethyl ( Meth) acrylate etc.], diphenylamine (meth) acrylamide [4-diphenylamine (meth) acrylamide, 2-diphenylamine (meth) acrylamide etc.], C6-C12 dialkenylamine [di (meth) allylamine etc.],
(C2-3) Tertiary amino group-containing vinyl monomer, for example, dialkyl (1 to 4 carbon atoms) aminoalkyl (2 to 6 carbon atoms) (meth) acrylate [dimethylaminoethyl (meth) acrylate, diethylaminoethyl ( Dialkyl (1 to 4 carbon atoms) aminoalkyl (2 to 6 carbon atoms) (meth) acrylamide [dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, etc. ] A tertiary amino group-containing aromatic vinyl monomer [N, N-dimethylaminostyrene, etc.],
(C2-4) Nitrogen-containing heterocycle-containing vinyl monomer [morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, N-vinylpyrrole, N-vinylpyrrolidone, N-vinylthiopyrrolidone, etc.] There is.
(C3) Amphoteric vinyl monomer:
For example, N- (meth) acryloyloxy (or amino) alkyl (C1-10) N, N-dialkyl (C1-5) ammonium-N-alkyl (C1-5) carboxylate (or sulfate) ), For example, N- (meth) acryloyloxyethyl N, N-dimethylammonium N-methylcarboxylate, N- (meth) acryloylaminopropyl N, N-dimethylammonium N-methylcarboxylate, and N- (meth) Acryloyloxyethyl N, N-dimethylammonium propyl sulfate, etc.
(C4) Nitrile group-containing monomer: for example, (meth) acrylonitrile.

  Further, as such a monomer, there is an aliphatic hydrocarbon vinyl monomer (d). For example, alkenes having 2 to 20 carbon atoms [ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, etc.] and alkadienes having 4 to 12 carbon atoms [butadiene, isoprene, 1,4- Pentadiene, 1,6-heptadiene, 1,7-octadiene, etc.].

  Furthermore, there are alicyclic hydrocarbon-based vinyl monomers (e): for example, cyclohexene, (di) cyclopentadiene, pinene, limonene, indene, vinylcyclohexene, and ethylidenebicycloheptene.

  Aromatic hydrocarbon vinyl monomer (f): 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.

  And vinyl esters, vinyl ethers, vinyl ketones (g): for example, vinyl esters of saturated fatty acids having 2 to 12 carbon atoms [vinyl acetate, vinyl propionate, vinyl butyrate, vinyl octoate, etc.], alkyl having 1 to 12 carbon atoms , Aryl ether or alkoxyalkyl vinyl ether [methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, 2-ethylhexyl vinyl ether, phenyl vinyl ether, vinyl 2-methoxyethyl ether, vinyl 2-butoxyethyl ether, etc.], and 1 to 8 carbon atoms And alkyl or aryl vinyl ketones [methyl vinyl ketone, ethyl vinyl ketone, phenyl vinyl ketone, etc.].

  Furthermore, esters of unsaturated polycarboxylic acids (h): for example, alkyl, cycloalkyl or aralkyl esters of unsaturated polycarboxylic acids, of which unsaturated dicarboxylic acids [maleic acid, fumaric acid, itaconic acid, etc.] Examples thereof include alkyl diesters having 1 to 8 carbon atoms [dimethyl maleate, dimethyl fumarate, diethyl maleate, dioctyl maleate].

  Also, polyoxyalkylene chain-containing vinyl monomer (without hydroxyl group) (i): for example, polyoxyalkylene glycol (alkylene group having 2 to 4 carbon atoms, degree of polymerization 2 to 50) or polyoxyalkylene polyol [ Mono (meth) acrylate of monoalkyl (carbon number 1 to 18) ether of polyoxyalkylene ether of 3 to 8 valent alcohol (alkyl group having 2 to 4 carbon atoms, polymerization degree 2 to 100) [for example, methoxy Polyethylene glycol (molecular weight 110 to 310) (meth) acrylate, lauryl alcohol ethylene oxide adduct (2 to 30 mol) (meth) acrylate, etc.] can also be used.

  And carboxyl group-containing vinyl monomer (j): For example, monocarboxyl group-containing vinyl monomer, for example, unsaturated monocarboxylic acid [(meth) acrylic acid, α-methyl (meth) acrylic acid, crotonic acid, Cinnamic acid, etc.], monoalkyl (carbon number 1 to 8) ester of unsaturated dicarboxylic acid [maleic acid monoalkyl ester, fumaric acid monoalkyl ester, itaconic acid monoalkyl ester, etc.]; containing two or more carboxyl groups Vinyl monomers such as maleic acid, fumaric acid, itaconic acid, citraconic acid and the like can be used as monomers for copolymerization.

  Of the additional monomers (c), (d), (e), (f), (g), (h), (i), and (j) described above, (c) is preferred. , (C) can be used in combination of two or more. Of the above (c), preferred are (c2), and more preferred are dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate.

  The hydroxyl value (hydroxyl value) of the poly (meth) acrylate containing a hydroxyl group used as this additive is preferably 10 to 100, more preferably 20 to 50, still more preferably 25 to 35. The measurement of the hydroxyl value is a numerical value obtained by measurement according to JIS K3342 (1961) and is a value indicating the amount of hydroxyl group in the additive.

  This poly (meth) acrylate containing hydroxyl groups, when blended with grease, retains an appropriate oil film on the lubricated sliding surface without adversely affecting the grease structure, and the chemical structure containing hydroxyl groups is also effective. Acting on the lubricating sliding surface. Therefore, grease blended with poly (meth) acrylate containing this hydroxyl group gives ideal lubricity on the sliding surface, and can suppress wear of lubricating parts of automobile parts and industrial parts. It is extremely effective for stable quality, ensuring reliability and extending life. Here, the major difference between lubricating oil and grease is that, in the case of grease, the thickener and additive that form the framework of the grease structure interact with each other. Not only is it not allowed, but it may also promote wear. Therefore, additives that provide stable and effective lubricity to the grease as in the present technology are very suitable.

[Arbitrary ingredients]
The grease composition of this embodiment further includes an optional antioxidant, rust inhibitor, oiliness agent, extreme pressure agent, antiwear agent, solid lubricant, metal deactivator, polymer, metal detergent, and nonmetal detergent. Additives such as coloring agents and coloring agents may be contained. For example, as an antioxidant, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butylparacresol, p, p′-dioctyldiphenylamine, N-phenyl-α-naphthylamine And phenothiazine. For example, examples of the rust inhibitor include oxidized paraffin, carboxylic acid metal salt, sulfonic acid metal salt, carboxylic acid ester, sulfonic acid ester, salicylic acid ester, succinic acid ester, sorbitan ester, and various amine salts. For example, oily agents, extreme pressure agents and antiwear agents include zinc sulfide dialkyldithiophosphate, zinc sulfide diallyldithiophosphate, zinc sulfide dialkyldithiocarbamate, zinc sulfide diallyldithiocarbamate, sulfurized dialkyldithiophosphate molybdenum, sulfide diallyldithiophosphate molybdenum. , Sulfurized dialkyldithiocarbamate molybdate, diallyldithiocarbamate molybdate, organic molybdate complex, sulfurized olefin, triphenyl phosphate, triphenyl phosphorothioate, tricresin phosphate, other phosphate esters, sulfurized oils and fats Can do. For example, the solid lubricant includes molybdenum disulfide, graphite, boron nitride, melamine cyanurate, PTFE (polytetrafluoroethylene), tungsten disulfide, graphite fluoride, calcium phosphate, and the like. Examples of the metal deactivator include N, N′disalicylidene-1,2-diaminopropane, benzotriazole, benzimidazole, benzothiazole, thiadiazole and the like. For example, examples of the polymer include polybutene, polyisobutene, polyisobutylene, polyisoprene, and polymethacrylate. For example, examples of the metal detergent include metal sulfonate, metal salicylate, and metal finate. For example, succinimide etc. can be mentioned as a nonmetallic detergent. These do not limit the invention.

≪Grease composition (mixing amount of each component) ≫
Next, the blending amount in the grease composition according to this embodiment will be described. Unless otherwise specified,% is mass%.

[Base oil]
The blending amount of the base oil is preferably 60 to 95% by mass, more preferably 70 to 90% by mass, and further preferably 75 to 90% by mass, based on 100% by mass of the entire grease composition.

[Thickener]
(Thickener)
The blending amount of the thickener {eg urea compound (eg alkyldiurea compound)} is preferably 1 to 20% by mass, more preferably 2 to 17% by mass, and still more preferably 100% by mass of the entire grease composition. 3 to 15% by mass.

[Additive]
(Hydroxyl-containing poly (meth) acrylate derivative)
The hydroxyl group-containing poly (meth) acrylate derivative is preferably 2 to 20% by weight, more preferably 4 to 10% by weight, based on 100% by mass of the entire grease composition.

(Other additives)
The other additive is, for example, 0.03 to 20% by mass with respect to the entire optional composition, with the total grease composition being 100% by mass.

(Particularly preferred blending mode)
Particularly preferred blending modes (particularly thickener and hydroxyl group-containing PMA) are as follows: Thickener type = (2-1) to (2-3), Thickener content = 7.5 to 15% by weight ( More preferably 10-15), the type of hydroxyl group-containing PMA (hydroxyl number = 20-50, weight average molecular weight = 1.0 × 10 ⁴ -2.0 × 10 ⁴ ), content of hydroxyl group-containing PMA = 7. 5 to 15% by weight.

≪Grease composition manufacturing method≫
The grease composition of the present embodiment can be manufactured by a generally-used grease manufacturing method, and is not particularly limited. As an example of a urea-based grease composition manufacturing method, And diurea thickener obtained by reacting 1 mol of diisocyanate which is a raw material of urea thickener and 2 mol of primary monoamine, or base oil and 2 mol of diisocyanate which is a raw material of urea thickener and primary diamine 1 1 mole of tetraurea grease obtained by reacting 2 moles of primary and monoamines, or base oil, 2 moles of diisocyanate and 1 mole of primary diamine, and 1 mole of primary monoamine and 1 mole of monoalcohol, which are raw materials for urea-based thickeners. A grease obtained by synthesizing a thickener such as triurea monourethane obtained by reaction. It is possible to have. For example, after the synthetic reaction of these thickeners in the base oil, the specific production method is raised to a temperature of about 180 ° C., then cooled, and the additive {containing hydroxyl group at a temperature of 100 to 80 ° C. Poly (meth) acrylate derivative} is mixed and sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease composition can be obtained using a kneader (eg, a three-roll mill).

≪Physical properties of grease composition≫
The grease composition of the drip point form preferably has a drip point of 180 ° C. or higher, more preferably 210 ° C. or higher, more preferably 250 ° C. or higher, and more than 260 ° C. or higher. Is particularly preferred. If the dropping point of the grease composition is 180 ° C. or higher, it is considered that the possibility of occurrence of lubrication problems, for example, loss of viscosity at high temperature, leakage and seizure associated therewith, can be suppressed. The dropping point refers to a temperature at which the viscous grease loses the thickener structure as the temperature increases. Here, the measurement of the dropping point can be carried out according to JIS K 22208.

Grease consistency this embodiment, the penetration test is preferably penetration of 000 No. 6 No. (85-475), more preferably consistency of No. 0 to 4 No. (175-385), More preferred is a consistency of No. 1 to No. 3 (220 to 340). The consistency indicates the physical hardness of the grease. Here, the consistency measurement method can measure the penetration consistency according to JIS K 22207.

Friction test high-speed four-ball wear resistance test: In accordance with ASTM D2596, ball bearing steel balls are used under conditions of a rotation speed of 1200 rpm, a load of 40 kgf, room temperature (temperature change), and 30 minutes. Evaluation was performed with the size of.

≪Use of grease composition≫
The grease composition of the present embodiment can be used for generally used machines, bearings, gears, and the like, and can exhibit excellent performance under more severe conditions, for example, high temperature conditions. For example, in automobiles, the engine periphery of starters, alternators and various actuators, propeller shafts, constant velocity joints (CVJ), power trains such as wheel bearings and clutches, electric power steering (EPS), braking devices, ball joints, door hinges It can be suitably used for lubricating various parts such as a handle part, a cooling fan motor, and a brake expander. In addition, construction equipment such as power shovels, bulldozers, crane cars, steel industry, paper industry, forestry machinery, agricultural machinery, chemical plants, windmill equipment, power generation equipment, drying furnaces, copying machines, rail cars, screw joints for seamless pipes, Etc., and particularly suitable for high temperature and high load sites. Other applications include hard disk bearings, plastic lubrication, cartridge grease, etc., but can be adequately adapted to these applications.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

≪Raw materials used in this composition≫
The raw materials used in the examples and comparative examples are as follows.
Thickener raw material thickeners A and B each have a diurea composition having the following chemical structure as a thickener.
Thickener A: Urea type I
(A) R ₁ NHCONHR ₂ NHCONHR ₁
Thickener B: Urea type II
(A) R ₁ NHCONHR ₂ NHCONHR ₁
(B) R ₃ NHCONHR ₂ NHCONHR ₃
(C) R ₁ NHCONHR ₂ NHCONHR ₃
Thickener C: Urea type III
(A) R ₄ NHCONHR ₂ NHCONHR ₄
(In the formula, R ₂ represents a diphenylmethane group, R ₁ represents an octyl group having 8 carbon atoms, R ₃ represents a lauryl group having 12 carbon atoms, and R ₄ represents a phenyl group having 6 carbon atoms.)
Thickener D: industrially available lithium 12 hydroxystearate.

Base oils A to C
Base oil A: Paraffinic mineral oil obtained by dewaxing solvent refining and belonging to Group I, 100 ° C. kinematic viscosity 14.28 mm ² / s, 40 ° C. kinematic viscosity 144.9 mm ² / s The viscosity index is 96.
Base oil B: Poly-α-olefin (PAO) synthetic oil belonging to Group IV, mixed with low-viscosity PAO and high-viscosity PAO, and adjusted to 100 ° C kinematic viscosity of 15.4 mm ² / s It is a thing. The mixed PAO has a kinematic viscosity at 40 ° C. of 118.9 mm ² / s and a viscosity index of 136.
Base oil C: oil obtained by GTL (Gas Liquid) synthesized by Fischer-Tropsch method, belonging to Group III, 100 ° C. kinematic viscosity 8.2 mm ² / s, 40 ° C. kinematic viscosity Of 47.9 mm ² / s and a viscosity index of 144.

Additive A: hydroxyl group-containing PMA (trade name: Include A-1070, manufactured by Sanyo Chemical Industries, Ltd .; Mw: 1.7 × 10 ⁴ , hydroxyl value 30)
Additive B: hydroxyl group-free PMA (trade name: Include V-815, manufactured by Sanyo Chemical Industries, Ltd .; Mw: 2.1 × 10 ⁴ )
Additive C: hydroxyl group-free PMA (trade name: Include 812, manufactured by Sanyo Chemical Industries, Ltd .; Mw: 3.3 × 10 ⁴ )
Additive D: Hydroxyl group-free PMA (trade name: Include C728, manufactured by Sanyo Chemical Industries, Ltd .; Mw: 4.5 × 10 ⁴ )
Additive E: ethylene-α-olefin copolymer (trade name: Lucant HC100, manufactured by Mitsui Chemicals, Inc.)
Additive F: Polybutene (trade name: Nisseki Polybutene HV-100, manufactured by JX Nippon Mining & Energy Corporation)

Example 1
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and the grease of Example 1 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the Group I base oil corresponding to the base oil A prepared in advance was put in a sealed grease prototype manufacturing pot, and immediately after that diphenylmethane 4 which is a raw material for urea thickener 4,4'-diisocyanate is charged and heated to 50 ° C with stirring. Next, octylamine and laurylamine are dissolved in the remaining 40% by weight of Group I base oil, and are sequentially placed in a trial production tank to produce a diurea type II thickener. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Then, the homogeneous grease of Example 1 was obtained using a three roll mill.

Example 2
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and a grease of Example 2 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the synthetic oil corresponding to the base oil B prepared in advance was put into a sealed grease prototype manufacturing kettle, and immediately after that diphenylmethane 4,4 which is a raw material for urea thickener. '-Add diisocyanate and heat to 50 ° C with stirring. Next, octylamine is dissolved in the remaining 40% by weight of synthetic oil, and placed in a prototype production kettle to produce a diurea type I thickener by reaction. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Then, the grease composition of Example 2 was obtained using a three roll mill.

Example 3
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and the grease of Example 3 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the Group III base oil corresponding to the base oil C prepared in advance was put into a sealed grease prototype manufacturing kettle, and immediately after that diphenylmethane 4 which is a raw material for urea thickener 4,4'-diisocyanate is charged and heated to 50 ° C with stirring. Next, octylamine is dissolved in the remaining 40% by weight of Group III base oil and placed in a prototype production kettle to produce a diurea type I thickener. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease of Example 3 was obtained using a three-roll mill.

Examples 4-6
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and greases of Examples 4 to 6 were obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the Group I base oil corresponding to the base oil A prepared in advance was put in a sealed grease prototype manufacturing pot, and immediately after that diphenylmethane 4 which is a raw material for urea thickener 4,4'-diisocyanate is charged and heated to 50 ° C with stirring. Next, octylamine and laurylamine are dissolved in the remaining 40% by weight of Group I base oil, and are sequentially placed in a trial production tank to produce a diurea type II thickener. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Then, the homogeneous grease of each of Examples 4 to 6 was obtained using a three-roll mill. In Examples 4 to 6, the amount of the base oil is balanced and the amount of the thickener is slightly adjusted as the amount of the additive is different.

Example 7
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and the grease of Example 7 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the Group I base oil corresponding to the base oil A prepared in advance was put in a sealed grease prototype manufacturing pot, and immediately after that diphenylmethane 4 which is a raw material for urea thickener 4,4'-diisocyanate is charged and heated to 50 ° C with stirring. Next, octylamine is dissolved in the remaining 40% by weight of Group I base oil and placed in a trial production kettle to produce a diurea type I thickener by reaction. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease of Example 7 was obtained using a three-roll mill.

Example 8
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and a grease of Example 8 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. The specific manufacturing method is to paste all the Group I base oil corresponding to the base oil A prepared in advance into the sealed grease prototype manufacturing pot, and immediately after that, diphenylmethane 4,4'-diisocyanate, which is the raw material of the urea thickener, is applied. Heat to 50 ° C. with stirring. Next, octylamine is mixed with the synthetic oil corresponding to the base oil B, laurylamine is mixed and dissolved in the group III corresponding to the base oil C, and the mixture is sequentially put into a trial production kettle to produce a diurea type II thickener. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease of Example 8 was obtained using a three-roll mill.

Example 9
The raw materials, base oil, and additives were measured and prepared so as to have the components and blending amounts shown in Table 1, and the grease of Example 7 was obtained according to a general urea grease manufacturing method. The molar ratio of diisocyanate, which is a thickener raw material of diurea grease, and primary amine used here is 1 mol to 2 mol, respectively. Specifically, 60 wt% of the total amount of the Group I base oil corresponding to the base oil A prepared in advance was put in a sealed grease prototype manufacturing pot, and immediately after that diphenylmethane 4 which is a raw material for urea thickener 4,4'-diisocyanate is charged and heated to 50 ° C with stirring. Next, aniline is mixed and dissolved in the remaining 40% by weight of Group I base oil and placed in a prototype production kettle to produce a diurea type III thickener by reaction. Further, heating is continued and the temperature is raised to about 180 ° C. to stabilize the thickener structure. Thereafter, the cooling is started, and the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added at a temperature of 80 ° C. during the cooling step, sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease of Example 9 was obtained using a three-roll mill.

Example 10
Prepare commercially available lithium 12 hydroxystearate and group I base oil corresponding to base oil A so as to have the components and blending amounts shown in Table 1, and prepare the total amount of base oil and lithium prepared in an open grease trial manufacture kettle. Stir 12 hydroxystearate and heat to 230 ° C. with stirring. After confirming that lithium 12 hydroxystearate is completely dissolved, the temperature is gradually lowered and the mixture is cooled at 80 ° C. At a temperature of 80 ° C., the hydroxyl group-containing poly (meth) acrylate derivative of Additive A is added and sufficiently stirred and mixed, and then cooled to room temperature. Thereafter, a homogeneous grease of Example 10 was obtained using a three-roll mill.

Comparative Example 1 to Comparative Example 3
In accordance with the production method of Example 6, a urea thickener was produced and reacted to obtain greases of respective comparative examples. Comparative Example 1 is a base grease not containing any additive. Moreover, the comparative example 2 mix | blends the additive B. FIG. Furthermore, the comparative example 3 mixes the additive C.

Comparative Example 4 to Comparative Example 6
In accordance with the production method of Example 1, a urea thickener was produced and reacted to obtain greases of respective comparative examples. Comparative Example 4 was formulated with additive D. In Comparative Example 5, additive E is blended. Furthermore, the comparative example 6 mix | blends the additive F. FIG.

  The results are shown in Table 1. As can be seen from Table 1, the greases according to Examples 1 to 10 have excellent wear resistance performance (wear scar diameter is 0.39 to 0.52).

Claims (2)

A base oil, a thickener, and a poly (meth) acrylate containing a hydroxyl group ,
Grease composition characterized urea grease composition der Rukoto.   The grease composition according to claim 1, wherein the hydroxyl value of the poly (meth) acrylate containing a hydroxyl group is 20 to 50.