JP5411454B2 - Lubricant composition - Google Patents

Description

  The present invention relates to an improvement of a lubricant composition, and more particularly to a lubricant composition formed by a thickener having a high thickening effect, that is, an excellent consistency yield.

Conventionally, as lubricant compositions that require wear resistance, organic phosphorus or sulfur-phosphorous additives such as tricresyl phosphate and zinc dithiophosphate are added to lubricating oils and semi-solid lubricants. Lubricants added as antiwear additives have been used.
In addition, sulfur-based extreme pressure agents such as sulfurized fats and various polysulfides and solid lubricants such as molybdenum disulfide, graphite, and melamine cyanurate have been used to improve lubricity in high-load environments. It is difficult to improve the wear resistance in the load region (including initial seizure resistance: the same applies hereinafter), and there are also disadvantages such as deterioration of oxidation stability and rubber / resin materials at high temperatures. And the safety to the environment and the human body was not sufficient.

  Furthermore, a lubricant composition containing calcium sulfonate is known as one that improves wear resistance in a high load region. For example, as a grease satisfying water resistance, rust resistance, heat resistance and load carrying capacity, a grease containing a calcium sulfonate complex containing calcium carbonate as a thickener is known (Patent Document 1).

However, conventionally used calcium sulfonate complex greases have a problem in that they lack heat resistance at high temperatures and durability against seizure lubrication. Further, in order to obtain wear resistance under high load conditions, a large amount of addition is necessary, and there is a disadvantage that the effect cannot be obtained with a small amount.
Japanese Patent Publication No. 5-8760

  The present invention provides a lubricant composition using a thickener having an excellent consistency yield.

The present inventors have found that a lubricant composition to which tribasic calcium phosphate is added in the course of testing and research of lubricants exhibits extremely excellent wear resistance even under high load conditions. Tricalcium phosphate has a thickening effect.
Furthermore, in the course of research, the above-mentioned tricalcium phosphate has a difference in the thickening effect depending on its shape, that is, an excellent thickening effect in the case of a spherical shape, in other words, a consistency yield. Based on these findings, the present invention has been completed.
The present invention is a lubricant composition using a tribasic calcium phosphate having a spherical shape. The spherical particle size is preferably about 3 μm or less, and usually about 0.5 to 60% by mass based on the total composition. This tricalcium phosphate is added to the liquid lubricating oil to make the present lubricant composition.

According to the present invention, the tribasic calcium phosphate having a spherical shape has an extremely excellent thickening effect, that is, a good consistency yield, and a good consistency yield is obtained with a small content of tricalcium phosphate. be able to.
In this way, when the amount used is the same as the conventional amount, the consistency is high (the consistency value is low), so that it is possible to obtain the necessary consistency with a small amount, and the high viscosity as in the conventional case. It is not necessary to use a large amount in order to obtain consistency, and there is little trouble when using other additives.
This lubricant composition can be easily obtained by adding tribasic calcium phosphate to mineral oil, synthetic oil, animal and vegetable oils, as well as conventional general lubricating oils and other liquid lubricating oils containing various additives. Dispersibility is good.
Furthermore, the lubricant composition containing this tricalcium phosphate has very good compatibility with various materials such as rubber and resin materials, reducing wear under severe conditions, reducing friction coefficient and suppressing temperature rise. And it is extremely safe for the environment and the human body.

The lubricant composition of the present invention is suitable for use under more severe load conditions as an application, and a highly viscous one is useful. Of course, it can be used for bearings, linear motion devices, joints, gears, and the like.
As its applications, for example, in automobiles, starter, alternator, and engine periphery of various actuator parts, propeller shaft, constant velocity joint (CVJ), power train such as wheel bearing and clutch, electric power steering (EPS), braking device And various parts such as a ball joint, a door hinge, a handle part, a cooling fan motor, and a brake expander.
In addition, construction machines such as excavators, bulldozers, crane cars, steel, paper industry, forestry, agricultural machinery, chemical plants, power generation equipment, drying furnaces, copying machines, railcars, seamless pipe screw joints, etc. It is also suitable for load parts.
Other applications include hard disk bearings, plastic lubrication, and cartridge grease.
And since the said tribasic calcium phosphate has almost no bad influence on an ecosystem, it can be used widely in various fields further.

Tribasic calcium phosphate in the present invention is generally but those having a chemical structure of the hydroxyapatite composition represented by _[Ca 3 _{(PO 4) 2] 3 · Ca (OH) 2,} Ca 3 ( Those represented by PO ₄ ) ₂ can also be used.
In the examples and the like described below in the present invention, [Ca ₃ (PO ₄ ) ₂ ] ₃ · Ca (OH) ₂ is used, and the content is also expressed in mass based on this.

The powder of tricalcium phosphate is usually indefinite, but in the present invention, a powder having a spherical shape is used. The sphere is preferably a fine one of about 3 μm or less.
The fine spherical tribasic calcium phosphate is usually in an agglomerated state and exists in a substantially spherical shape with a size of about 5 to 500 times, but is mixed with a liquid lubricating oil as described below, and further subjected to a roll treatment. When kneaded by, for example, the agglomerated state is released, and the original fine spheres are dispersed and act.

As what contains the said tribasic calcium phosphate, the general lubricating oil which already contains various additives other than liquid lubricating oils, such as mineral oil, synthetic oil, and animal and vegetable oil, can also be used.
As the base oil used in the liquid lubricating oil described above, mineral oil, synthetic oil, animal and vegetable oils, and mixed oils thereof, which are used in ordinary lubricating oils, can be used as appropriate.
In particular, base oils belonging to Group 1, Group 2, Group 3, Group 4, etc. in the API (American Petroleum Institute) base oil category can be used alone or as a mixture.

  For Group 1 base oils, for example, paraffin obtained by applying a suitable combination of solvent refining, hydrotreating, dewaxing, etc., to a lubricating oil fraction obtained by atmospheric distillation of crude oil There are mineral oils.

  For Group 2 base oils, for example, paraffinic mineral oil obtained by appropriately combining refining means such as hydrocracking and dewaxing for lubricating oil fractions obtained by atmospheric distillation of crude oil There is. Group 2 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 3 base oil and Group 2 plus base oil include, for example, a paraffinic mineral oil produced by advanced hydrorefining and a dewaxing process for a lubricating oil fraction obtained by atmospheric distillation of crude oil. There are base oils refined by the ISODEWAX process for converting and dewaxing the produced wax to isoparaffins, and base oils refined by the mobile WAX isomerization process, and these can also be suitably used in the present invention.

  Synthetic oils include, for example, polyolefins, diesters of dibasic acids such as dioctyl sebacate, polyol esters, alkylbenzenes, alkylnaphthalenes, esters, polyoxyalkylene glycols, polyoxyalkylene glycol esters, polyoxyalkylene glycol ethers, polyphenyl ethers. , Dialkyl diphenyl 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. Particularly preferred are polyolefins called poly α-olefins (PAO), which are Group 4 base oils.

  GTL (Gas Liquid) synthesized by the Fischer-Tropsch method, which is a natural gas liquid fuel technology, has an extremely low sulfur content and aromatic content compared to mineral oil base oil refined from crude oil. Is extremely high, so that it has excellent oxidation stability and very low evaporation loss, and can be suitably used as the base oil of the present invention.

The lubricant composition of the present invention can be easily obtained by adding tribasic calcium phosphate to the above-mentioned liquid lubricating oil, mixing them well, and kneading them by roll treatment or the like. As described above, the spherical fine tribasic calcium phosphate is usually in an agglomerated state and is large in size, but the agglomerated state is released by the roll treatment or the like, so that the original fine spherical shape becomes a liquid lubricating oil. Kneaded and dispersed to act.
The consistency of the lubricant composition increases as the amount of tricalcium phosphate added increases. The amount of tricalcium phosphate used is about 0.5 to 60% by weight, preferably about 1 to 50% by weight, more preferably about 3 to 40% by weight, based on the total amount of the lubricant composition. It is good to. As a result, a grease-like lubricant composition with increased consistency can be obtained.
When the blending amount of tribasic calcium phosphate is less than 1% by mass with respect to the total amount of the composition, it does not become a state normally referred to as grease, but it can be obtained because an increase in consistency is observed. It can be used for applications that match the sticky state. Moreover, when it exceeds 40 mass%, although a lubricant composition will become hard, it can be used for the use according to the state.

The lubricant composition of the present invention further includes a rust inhibitor, an anticorrosive agent, an antioxidant, an extreme pressure agent, a solid lubricant, a dispersant, a surfactant, an adhesion improver (polymer, etc.) depending on the application. ), Oiliness agents, friction reducing agents, conventional antiwear agents and other additives can be used in combination as appropriate.
Examples of the rust inhibitor and the anticorrosive agent include those generally used. For example, organic acid derivatives can be used. Among them, succinic acid ester derivatives, aspartic acid derivatives, sarcosine acid derivatives, 4-nonylphenoxyacetic acid and the like are particularly preferable.
In addition, there are organic amine derivatives and organic amide derivatives. Among them, diethanolamine, monoalkyl primary amine, diamine / difatty acid salt, diamine, amide of isostearic acid, amide of oleic acid and the like are preferable.
Others include sulfonates (Ca sulfonate, Na sulfonate, Ba sulfonate, etc.), sulfurized fatty acids, surfactants (sorbitan trioleate, sorbitan tristearate, sorbitan monolaurate, mono-diglyceride of stearic acid / oleic acid) Etc.) are also preferred.
In addition, a naphthenate, an alkali metal salt of a dibasic acid, an alkaline earth metal salt of a dibasic acid, or a benzotriazole derivative, a benzothiazole derivative, a benzimidazole derivative, or a thiocarbamate may be used. , Sodium sebacate and benzotriazole, or a combination thereof.

As the antioxidant, an antioxidant such as amine, phenol, phosphite, sulfur, dialkyldithiophosphate and the like can be used.
Extreme pressure agents and antiwear agents include sulfurized fats and oils, sulfurized olefins, sulfur compounds such as zinc dithiocarbamate and dithiocarbamate such as molybdenum dithiocarbamate, phosphates, acidic phosphates, phosphites, acidic sublimates. Phosphorus compounds such as phosphoric acid esters, phosphoric acid ester amine salts, phosphorous acid ester amine salts, acidic phosphoric acid ester amine salts, acidic phosphorous acid ester amine salts, etc., thiophosphoric acid esters, zinc dithiophosphate, dithiophosphorus It is possible to use sulfur phosphorus compounds such as dithiophosphate such as molybdenum acid, molybdenum amine compounds and other molybdenum compounds.
Examples of the solid lubricant include molybdenum disulfide, graphite, melamine cyanurate, boron nitride, mica, PTFE (polytetrafluoroethylene), and the like.
Of course, the other additives described above can be used in a state of being added in advance to a commercially available liquid lubricant or semi-solid lubricant.

The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereby.
For the examples and comparative examples, the following samples (commercial liquid lubricants and the like) were prepared.
(1) Mineral oil: Paraffinic mineral oil: one with a kinematic viscosity at 100 ° C. of about 15 mm ² / s (2) PAO: Commercially available polyalphaolefin oil: SHF403 manufactured by ExxonMobil (kinematic viscosity at 100 ° C. about 40 mm ² / s)
(3) Ether oil: Commercially available alkyl diphenyl ether oil (Moleco High Luve LB-100 manufactured by Matsumura Oil Research Co., Ltd. (kinematic viscosity at 100 ° C. is about 12.6 mm ² / s)
(4) [Ca ₃ (PO ₄ ) ₂ ] ₃ · Ca (OH) ₂ having a chemical structure with a hydroxyapatite composition having a spherical shape with a particle size in the range of 0.2 to 0.3 μm, and an average aggregated Spherical particles having a particle diameter of 19.7 μm (5) [Ca ₃ (PO ₄ ) ₂ ] ₃ · Ca (OH having an average particle diameter of 4.7 μm and an amorphous amorphous hydroxyapatite composition ₂
(6) [Ca ₃ (PO ₄ ) ₂ ] ₃ · Ca (OH) ₂ having a chemical structure of hydroxyapatite composition with an average particle diameter of 3.5 μm and an irregular shape

(Examples 1-6, Comparative Examples 1-8)
Examples 1 to 6 and Comparative Examples 1 to 8 were prepared according to the formulations shown in Tables 1 to 3.

About the lubricant composition of Examples 1-6 and Comparative Examples 1-8, the test regarding the consistency was done and evaluated.
(1) Consistency: About the consistency of the grease specified in JIS K2220 (ASTM D1403), the consistency (25 ° C., 60 W) and, if necessary, the immiscibility (25 ° C., 60 W) were measured.
As for the consistency, the smaller the numerical value, the higher the consistency.

(Discussion)
As shown in Table 1, the paraffinic mineral oil of Example 1 containing 20% by mass of spherical tribasic calcium phosphate having a particle size of 0.2 to 0.3 μm is amorphous with a particle size of 4.7 μm of Comparative Example 1. Compared to those containing the same amount, the values of the penetration and immiscibility are much lower. The particle size of 0.2 to 0.3 μm in Example 2 and 30% by mass of spherical tribasic calcium phosphate is 4.7 μm in Comparative Example 2 and irregular, and the particle size in Comparative Example 3 is 3. The numerical values of miscibility and immiscibility are significantly smaller than those containing the same amount of each of 5 μm amorphous calcium phosphates. In addition, Example 1 is slightly smaller than Comparative Example 2 and Comparative Example 3.
Moreover, as shown in Table 2, the same results as above were obtained between Example 3, Example 4, and Comparative Example 4, Comparative Example 5, and Comparative Example 6 using PAO instead of paraffinic mineral oil. It has been.
Further, as shown in Table 3, ether oil was used in place of paraffinic mineral oil, and 10% by mass of spherical tribasic calcium phosphate having a particle diameter of 0.2 to 0.3 μm in Example 5 and 20 in Example 6 were used. Those containing 5% by mass have lower mixed and immiscible consistency than Comparative Examples 7 and 8 having a particle size of 4.7 μm and containing 10% by mass and 20% by mass of amorphous calcium phosphate. ing.
Thus, the lubricant compositions of Examples 1 to 6 in which 10 to 30% by mass of spherical tribasic calcium phosphate having a particle size of 0.2 to 0.3 μm were contained in a commercially available lubricating oil were comparative examples. It can be seen that the particle size of 1 to 8 is less than 5 μm and the amount is increased with a smaller amount of tricalcium phosphate than that of an irregular shape, an appropriate consistency is obtained, and the increase effect is high.

Claims (4)

A lubricant composition comprising spherical tribasic calcium phosphate having a particle size of 3 μm or less . The lubricant composition according to claim 1 , comprising 0.5 to 60% by mass of tricalcium phosphate based on the total composition. The lubricant composition according to claim 2 , wherein the lubricant composition contains a liquid lubricant based on at least one of mineral oil, synthetic oil, and animal and vegetable oils. A bearing, a linear motion device, a joint, or a gear in which the lubricant composition according to claim 1 is used as a lubricant.