TWI443188B - Lubricant composition and lubricating system using the same - Google Patents

Description

Lubricant composition and lubrication system using the same

The present invention relates to a lubricant composition which is semi-solid at normal temperature, and particularly relates to an alloy which is excellent in anti-wear properties and extreme pressure properties and has a high dynamic friction coefficient. Agent composition. The invention further relates to a lubrication system for using the lubricant composition on a transmission mechanism.

In recent years, multi-functionality, high performance, environmental response, energy conservation, and durability have become important key technologies in various industrial technologies. Examples of environmental issues include the reduction of carbon dioxide emissions, the saving of electricity, the conservation of energy, and the effective use of resources. Therefore, in various mechanical systems such as small precision machines, industrial machines, and transportation systems, in addition to improving the environment, it is characterized by durability, reliability, and high performance.

In terms of durability, for example, the lubricity of the sliding portion of the machine is required to be effectively maintained until the life of the article. In recent years, the lubrication conditions of mechanical systems have become increasingly stringent, and lubricating oils must have higher performance lubricity. Lubricating agents include liquid lubricating oils and semi-solid lubricating greases, which are used separately for appropriate use.

The popularity of information machines is growing. Commercial designs for mobile phones and notebook computers have also been commercialized. Among these products, the display surface and the operation portion of some products are opened and closed, and the opening and closing is performed by a hinge member of a so-called hinge (Hinge), and is operated at the beginning of opening and closing. From the standpoint of sliding and suppressing stick-slip, it is necessary to minimize the difference between the static friction coefficient and the dynamic friction coefficient, and in the use of the machine, in order to maintain the required opening and closing angle for a long time, it is necessary to increase the static friction as much as possible. coefficient. Such a shaft is often used in an environment where consumers are in direct contact with it, and it is necessary to completely avoid the contamination caused by oil leakage, so liquid lubricating oil is not suitable. On the other hand, the grease can suppress oil leakage at normal temperature. However, if the oil is separated from the thickener by the temperature rise of the sliding portion, there is a problem that oil leakage occurs and the initial lubricating performance cannot be maintained. In addition to the rotating shaft, in terms of a transmission mechanism that requires high transmission capability of the oil agent, there are mentioned, for example, a gear, a belt, a chain, a steel cable, a mechanical stepless speed change machine, and the like. Such a demand mechanism is widely used in various industrial machinery such as home electrical appliances, OA machines, confidential machinery, construction machinery, and the like, and transportation systems such as automobiles, motorcycles, bicycles, and railways. In particular, in the case of a mechanical stepless speed changer, it is required to have a high dynamic friction coefficient and a traction coefficient.

In addition to having sufficient lubricity, the transmission mechanism must have a high dynamic friction coefficient and a traction coefficient. In order to achieve a high dynamic friction coefficient, a conventional naphthene base oil or an anthrone base oil is used. These base oils are used as a traction oil by blending an antioxidant, an anti-wear agent, or the like. However, since the traction oil is in a liquid state, oxygen is dissolved in the oil to be oxidized and deteriorated, or evaporates due to an increase in temperature, or leaks through the sealing portion, which causes a problem in that the mechanical system is persistent. On the other hand, compared with the case of using lubricating oil, the grease may not be used as a closed structure, but the oil is separated from the thickener at a high temperature, once the oil is separated. If it is divided into a tackifier, it cannot be restored to its original shape, so that the oil agent in the sliding portion is insufficient to exhibit the initial performance, or the oil to be separated may be contaminated.

In particular, in recent years, it has been strongly demanded that mechanical systems are highly functional, miniaturized, and durable, and that higher performance is required in terms of lubricants, and in particular, it is required to be smoothly lubricated even with a small amount of oil.

The inventors of the present invention have proposed a thermoreversible gel-like lubricious composition, a bearing lubricant, and a bearing system using the same (Patent Document 2), but for the notebook type The transmission mechanism of a computer or a mobile phone, and a transmission mechanism such as a mechanical stepless transmission are still strongly entrenched in expecting a lubricant having a high dynamic friction coefficient and wear resistance.

[Patent Document 1] Japanese Patent No. 3775986

[Patent Document 2] International Patent Publication No. WO2006-051671

[Non-Patent Document 1] (Society) Japanese Society of Tribologist, Friction Manual, Yangxiantang Publishing (2001) P247.

An object of the present invention is to provide a lubricant composition for solving the above problems, and the lubricant composition of the present invention coats a very small amount of an oil agent on a lubricating sliding portion, and has high lubricity even in a film state, and exhibits Conducive to the high dynamic friction coefficient of the power transmission, and semi-solid at room temperature. The present invention further provides a lubrication system for using the lubricant composition in a transmission mechanism.

In order to solve the above problems, the inventors of the present invention have dealt with the lubricating base oil, The chemical substances, additives, and the like which maintain lubricity, and the combination of these, have been contemplating the present invention as a result of intensive research.

That is, the present invention is a lubricant composition and a lubricating system as follows: (1) A lubricant composition characterized by being semi-solid at normal temperature and containing 10 to 98.9 mass% selected from %Cp It is at least one liquid base oil of a hydrocarbon-carbon base oil, a phosphate ester, and a silicone of 70 or less, 1 to 20% by mass of an alkaline earth metal salt, and 0.1 to 89% by mass of a guanamine compound.

(2) The lubricant composition according to (1), wherein the alkaline earth metal salt is selected from the group consisting of sulfonate, phenate, and salicylate having a total base number of TBN: 5 to 400 mgKOH/g. At least one or more of them.

(3) The lubricant composition according to (1) or (2), wherein the guanamine compound is at least one compound represented by the following formulas (1) to (3): R -CO-NH-R2 (1) R ³ -CO-NH-A ¹ -NH-CO-R ⁴ (2) R ⁵ -NH-CO-A ² -CO-NH-R ⁶ (3) (in the formula (1) to the formula (3), R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a saturated or unsaturated chain hydrocarbon group having 5 to 25 carbon atoms; R ² may also be a hydrogen atom; A ¹ and A ² are selected The alkyl group having from 1 to 10 carbon atoms, the phenyl group or the alkyl group having 7 to 10 carbon atoms and the divalent hydrocarbon group having 1 to 10 carbon atoms.

(4) The lubricant composition according to (3), wherein the indoleamine compound represented by the formulae (1) to (3) is: each of R ¹ , R ² , R ³ , R ⁴ , R ⁵ and R ⁶ Independently, it is a saturated chain hydrocarbon group having 12 to 20 carbon atoms, or an indoleamine compound in which R ² is a hydrogen atom, and/or at least one of each of R ¹ and R ² , R ³ and R ⁴ , R ⁵ and R ⁶ . It is a guanamine compound having an unsaturated chain hydrocarbon group having 12 to 20 carbon atoms.

(5) A lubricating system characterized in that any one of the lubricant compositions (1) to (4) is used in a transmission mechanism.

(6) A mechanical stepless speed changer is used as a transmission mechanism, in particular, a power transmitter is provided by an oil agent capable of maintaining a hinge of a predetermined angle (Hinge) and a high traction coefficient.

The lubricant composition according to the present invention is applied to the lubricating sliding portion by a small amount, and forms a stable film upon sliding, thereby achieving a special effect of exhibiting high extreme pressure and high dynamic friction coefficient. Since the lubricant composition of the present invention has thermal reversibility, exhibits a semi-solid state at normal temperature, and exhibits a uniform liquid state at a temperature above the melting point of the guanamine compound, heating and cooling are performed at the sliding portion. The liquid-semi-solid is repeated, leaving the sliding portion and maintaining a semi-solid state at a temperature that does not rise above the melting point. Therefore, there is no oxidative degradation, evaporation disappearance, oil leakage, etc., and it is possible to effectively use a lubricant as a transmission element mechanism such as a gear, a conveyor belt, a chain, a steel cable, a rotating shaft, or a mechanical stepless speed changer.

The lubricant composition of the present invention is characterized in that it is semi-solid at normal temperature and contains 10 to 98.9 mass% of a liquid base oil, 1 to 20 mass% of a metal salt, and 0.1 to 89 mass% of bismuth. Amine compound, such as pre-coated When the cloth is required to be lubricated, it is liquid and in a state of being lubricated, and exhibits a high dynamic friction coefficient. It is especially suitable for operation requiring extreme pressure lubrication in low-speed, high-load operation with seizure problems. In addition to exhibiting high lubricity under the film, and because oil retention is good, it is not prone to oil shortage, so it is not easy to cause enthusiasm. Further, in the lubricant composition of the present invention, when the sliding portion of the transmission element mechanism starts to operate, the temperature of the sliding portion rises from a semi-solid state to a liquid state and enters a narrow sliding portion, but does not leave the sliding portion. The part that conducts the frictional heat remains semi-solid without the risk of oil leakage, and the periphery can be kept clean.

In addition, "normal temperature" as used herein means a general temperature in a room, specifically, it is -20 to 50 ° C, and more generally, it is a temperature environment of about -10 to 30 ° C.

The lubricant composition can attain a high coefficient of dynamic friction, for example, preferably from 0.1 to 0.3, particularly preferably from 0.14 to 0.20, more preferably from 0.15 to 0.18.

[liquid base oil]

The liquid base oil used in the present invention is at least one selected from the group consisting of a hydrocarbon base oil having a % Cp of 70 or less, a phosphate ester, and an anthrone. The hydrocarbon-based oil, the phosphate ester, and the anthrone can be used singly or in combination of two or more.

As the hydrocarbon base oil having a %Cp of 70 or less, an alkylcycloalkane or an alkylbenzene may be used, and a mineral base oil may also be used. Hydrocarbon-based oils are composed of hydrocarbons, mostly containing naphthenes and cyclic aromatics, that is, the sum of %Cn and %Ca must exceed 30. The viscosity index of the hydrocarbon-based oil is 80 or less, particularly preferably 20 or less, and usually is -400 or more.

The physical properties of the liquid base oil are not particularly limited. Preferably, the dynamic viscosity at 40 ° C is 5 to 5000 mm ² /s, preferably 50 to 3000 mm ² /s, and 500 to 2000 mm. ² / s is better. In addition, %Ca, %Cp, and %Cn were determined according to the ndM loop analysis defined by ASTM D3238.

The alkylcycloalkanes are synthetic cycloalkane or naphthenic mineral oils. The alkylbenzenes are synthetic hard alkylbenzenes and soft alkylbenzenes. The phosphate ester may be an orthophosphate or a phosphite, and examples thereof include tricresyl phosphate and the like. Examples of the fluorenone oils include polydimethyl siloxane, polymethyl phenyl siloxane, and the like.

Among them, a hydrocarbon base oil having a %Ca of 10 or less is also suitable. Specifically, for example, an alkylcycloalkane has high dynamic friction characteristics and is excellent in lubricity. These base oils may be used alone or in combination of two or more kinds as long as they satisfy the above physical properties.

The liquid base oil is formulated so that the lubricant composition which is semi-solid at normal temperature is preferably contained in an amount of 10 to 98.9 mass%, preferably 30 to 97 mass%, more preferably 70 to 93 mass%. . When the amount of the liquid base oil is less than the above range, it is not preferable because the high dynamic friction characteristics of the base oil cannot be obtained.

[Alkaline earth metal salt]

In the present invention, an alkaline earth metal salt such as Ca, Ba or Mg is used to increase the dynamic friction coefficient, and an organic acid salt of an alkaline earth metal is preferred. As the organic acid, a carboxylic acid, a sulfonic acid, a phenol, a phosphonic acid, a salicylic acid or the like can be used. In particular, the alkaline earth metal salt is preferably at least one selected from the group consisting of a sulfonate, a phenate, and a salicylate, and a sulfonate, a phenate, a salicylate, or the like of a Ca alkaline earth metal. In particular, sulfonates are suitable. These are sold as metal-based detergents. The alkaline earth metal salts may contain an overbased component derived from a carbonate. Specifically, an alkaline earth metal salt having a total base number of 5 to 400 mgKOH/g, especially 50 to 400 mgKOH/g, can be applied.

The blending of the alkaline earth metal salt is preferably from 1 to 20% by mass, more preferably from 2 to 20% by mass, even more preferably from 2 to 10% by mass, based on the lubricant composition which is semi-solid at normal temperature after the treatment. When the amount of the metal salt is less than the above range, the friction property is not effectively provided. On the other hand, when the amount of the compound exceeds the range, the cost is increased because the effect is increased, which is not preferable.

[guanamine compound]

The guanamine compound used in the present invention is a fatty acid guanamine compound having one or more guanamine groups (-NH-CO-), and a monodecylamine having one guanamine group represented by the following formula (1) can be suitably used, and The bis-guanamine having two guanamine groups represented by the formula (2) and the formula (3). It is preferred to use a combination of monodecylamine and biguanide.

R ¹ -CO-NH-R ² (1)

Wherein R ¹ and R ² are each independently a saturated or unsaturated chain hydrocarbon group having 5 to 25 carbon atoms; and R ² may be a hydrogen atom.

R ³ -CO-NH-A ¹ -NH-CO-R ⁴ (2)

R ⁵ -NH-CO-A ² -CO-NH-R ⁶ (3)

In the formulae (2) and (3), R ³ , R ⁴ , R ⁵ and R ⁶ are each independently a saturated or unsaturated chain hydrocarbon group having 5 to 25 carbon atoms; and A ¹ and A ² are selected from carbon numbers. The alkylene group having 1 to 10 alkyl groups, phenylene groups or alkyl groups having 7 to 10 carbon atoms has a carbon number of 1 to 10 carbon atoms. Further, when the alkyl group is a phenyl group, it may be a divalent hydrocarbon group in which a phenyl group is bonded to two or more alkyl groups and/or an alkyl group.

The monodecylamine compound is represented by the above formula (1), and a part of hydrogen constituting R ¹ and R ² may be substituted with a hydroxyl group. Such a monoamine compound may specifically be, for example, a saturated fatty guanamine such as laurylamine, palmitoylamine, stearylamine, behenamide or hydroxystearate; oleic acid amine, mustard amide, etc. Saturated fatty decylamine; and saturated or unsaturated long-chain fatty acids such as stearyl stearylamine, oleyl linoleamide, oleyl stearylamine, stearyl decylamine, and long-chain amine-substituted guanamine Classes, etc.

Among the monoamine compounds, preferred are the guanamine compounds: R ¹ and R ^{2 of the} formula (1) are each independently a decylamine compound having a saturated chain hydrocarbon group having 12 to 20 carbon atoms and/or At least one of R ¹ and R ² is a decylamine compound having an unsaturated chain hydrocarbon group of 12 to 20 carbon atoms, and more preferably a mixture of two decylamine compounds. Further, a monodecylamine compound having an unsaturated chain hydrocarbon group as an oil group having an unsaturated bond at a carbon number of 18 is preferred. Specifically, it is preferable to use oil amide or oil-based guanamine to form a film on the sliding portion and hold it, thereby ensuring effective release of the film retention property of the entanglement.

The biguanide compound is a compound represented by the above formula (2) or (3) in the form of a guanamine of a diamine or a guanamine of a diacid. Further, in the formulae (2) and (3), in the hydrocarbon group represented by R ³ , R ⁴ , R ⁵ and R ⁶ , particularly, A ¹ and A ² , a part of hydrogen may be substituted by a hydroxyl group (-OH). .

The guanamine compound represented by the formula (2) may specifically be exemplified by ethylenebisstearylamine, ethylenebisisostearylamine, ethylenebisoleamide, methylenebislauric acid Amine, hexamethylene bis-indolylamine, hexamethylene bishydroxystearylamine, m-xylylene bis-stearylamine, and the like. Specific examples of the guanamine compound represented by the formula (3) include N, N'-distearoyl decylamine.

In the case of the bis-amine compound, as in the case of the monoamine compound, it is preferred to use the following guanamine compound: R ³ and R ⁴ of the formula (2) and R ⁵ and R ^{6 of the} formula (3). A guanamine compound which is independently a saturated chain hydrocarbon group having 12 to 20 carbon atoms and/or a ruthenium of R ³ and R ⁴ and at least one of R ⁵ and R ⁶ is an unsaturated chain hydrocarbon group having 12 to 20 carbon atoms. An amine compound is preferred, and a mixture of two guanamine compounds is more preferred. In the point of ensuring film retention, it is preferred that the unsaturated chain hydrocarbon group is an oleyl group having an oil group having an unsaturated bond of 18 carbon atoms. Examples of such a compound include ethylene bisamine and hexamethylene bis decylamine.

When the guanamine compound is uniformly mixed with the liquid base oil, a gel-like lubricious composition is formed at normal temperature. Therefore, in addition to the action of the semi-cured compound which is semi-cured (gelled) to the liquid base oil, the guanamine compound is melted by friction heat to become a liquid in the state in which the lubricating property of the lubricant composition is exhibited. The lubricant composition functions. When it is intended to be used as a liquid at a normal temperature in a semi-solid state at a high temperature, the melting point of the applicable guanamine compound is preferably from 50 to 200 ° C, more preferably from 80 to 180 ° C, and further, the molecular weight is from 100 to 1,000. Good, 150 to 800 is better.

In addition, due to the design limitation of the mechanical system, even in the sliding portion where only a small amount of oil can be used, in order to prevent the phenomenon of melting in a severe lubrication environment, the oil must be strongly adsorbed and adhered. Slide the surface and keep the oil film. Therefore, it must be an oily agent with adhesion, and thus In the present invention, when the hydrocarbon group of the indoleamine compound of the semi-cured compound is found to be unsaturated, the adhesion is increased. When the adhesion is increased, the sliding surface can be coated into a film shape, and even in a severe lubricating environment, it is difficult to cause an insufficient oil film, and the lubricating performance can be improved. In the case of an unsaturated chain hydrocarbon group, a bisamine compound having an oil group having an unsaturated bond at a carbon number of 18 is preferred.

The blending of the guanamine compound is preferably from 0.1 to 90% by mass, more preferably from 1 to 50% by mass, even more preferably from 5 to 20% by mass, based on the lubricant composition which is semi-solid at normal temperature after the treatment. When the blending amount of the guanamine compound is less than the above range, it is not preferable because the gel-like composition cannot be formed at normal temperature. On the other hand, when the blending amount is outside the range, it is difficult to operate because it is too hard.

[Modulation of lubricant composition]

The lubricant composition which is semi-solid at normal temperature in the present invention is not particularly limited, and can be prepared by uniformly mixing a liquid base oil, a metal salt, and a guanamine compound in the above-described mixing ratio. For example, the liquid base oil, the metal salt, and the guanamine compound are each weighed in a predetermined amount, heated to a temperature equal to or higher than the melting point, and stirred to a uniform liquid state, and then obtained by cooling to form a semi-solid state.

In the composition of the present invention, additives such as a known extreme pressure agent, an anticorrosive agent, an antiwear agent, a rust preventive, an antioxidant, and an antifoaming agent can be appropriately formulated. Examples of the extreme pressure agent and the anti-wear agent include zinc dialkyl dithiophosphate (ZnDTP), a sulfur compound, and a phosphorus compound; examples of the anticorrosive agent include a thiadiazole derivative, a benzotriazole, and the like. Derivatives; rust inhibitors can be listed For example, fatty acid partial esters, phosphorus-based compounds, and the like; antioxidants include, for example, phenolic and amine-based compounds, and anthrone-based compounds, PMA polymers as defoamers; and pour point depressants (PPD: pour- Point depressant), PMA polymer as a viscosity index improver (Viscosity Index Improver). Further, a form of a so-called additive combination in which a plurality of the above various additives are mixed in advance may also be used.

The lubricant composition which is semi-solid at normal temperature in the present invention is used in a mechanical mechanism (sliding portion) which requires lubrication, and becomes a liquid state due to frictional heat and saturates in the sliding portion during sliding, in metal or resin The solid surface of the sliding portion formed by the film forms a film to lubricate the sliding portion. If the sliding is stopped, the temperature is lowered, and the lubricant composition in a liquid state returns to a semi-solid state (gel-like shape). Moreover, since the lubricant composition of the present invention has a high melt load and a high dynamic friction coefficient, and maintains excellent friction characteristics for a long period of time, it is suitable for use in low-speed, high-load extreme pressure operation, and can also be used in It is difficult to replenish the sliding portion of the lubricant or the sliding portion of the device that cannot be unassembled once assembled. Further, the lubricant composition of the present invention can repeatedly withstand the pressure of temperature rise and cooling accompanying use and non-use, and the gel (semi-solid) structure can be reconstructed to avoid leakage. The pollution caused by oil is not easy to evaporate and has a long service life.

Therefore, it can be fully used as a substitute for the conventional liquid traction oil, for example, gears, conveyor belts, chains, steel cables, rotating shafts, mechanical stepless speed changers, etc., and can also be applied to high-load transmission components. Institutional. Particularly suitable applications include, for example, a rotary notebook computer, a mobile phone, or an electronic dictionary that requires maintenance of a desired angle. A mechanical stepless speed changer that transmits power by lubricating oil with a high dynamic friction coefficient.

[Examples]

The invention is illustrated in more detail below on the basis of the examples, but the invention is not limited by the examples.

[liquid base oil]

The following three kinds of liquid base oils were used to prepare the lubricant compositions used in the examples and the comparative examples.

Base oil A: synthesis of naphthenes (Techtrac M3Conc by Tecanmen)

Base oil B: soft alkyl benzene (dynamic viscosity (40 ° C): 32 mm ² / s)

Base oil C: α-olefin oligomer (SHF-400 manufactured by Mobil)

The physical properties of the three liquid base oils are shown in Table 1. Further, a predetermined amount of an additive such as an antioxidant or an anti-wear agent is preliminarily formulated in the liquid base oil to have a basic property (antioxidation, abrasion resistance, etc.) of the lubricating oil.

[guanamine compound]

The following indoleamine compounds were used in the liquid base oil for semi-solidification.

Indole A: Ethylene bis-indoleamine (Slipaks O, manufactured by Nippon Kasei Co., melting point 119 ° C)

Indoleamine B: Ethylene distearylamine (Slipaks E, manufactured by Nippon Kasei Co., melting point 145 ° C)

[Alkaline earth metal salt]

The following two compounds are used for the alkaline earth metal salt.

Ca sulfonate: total base number 300mgKOH/g

Ca salicylate: total base number 70mgKOH/g

[grease]

For comparison with the lubricant composition of the present invention, a commercially available lithium (Li) grease (manufactured by the Japanese energy company for the Knicks) is used. Fat No. 2; consistency number 2 (mixed consistency range 265 to 295)) was taken as Comparative Example 4.

[Modulation of lubricant composition]

Base oil A (synthetic cycloalkane), base oil B (alkylbenzene), and base oil C (α-olefin oligomer) as the above liquid base oil are used, respectively; and guanamine A as a guanamine compound (B) Examples are the preparation of Examples 1 to 6 and Comparative Examples in the following order, with the addition of acesulfame amine and guanamine B (ethylene bis-lipidamine); and the addition of Ca sulfonate and Ca salicylate as alkaline earth metal salts. 3 test oil (lubricant composition).

In a stainless steel beaker, a predetermined amount of liquid base oil, alkaline earth metal salt, and guanamine compound were weighed in proportion to the proportion (% by mass) of the test oil processed in the upper part of Table 2, and each was obtained in an amount of about 100 ml. The test oil was stirred at a temperature above the melting point of the guanamine compound (melting point + 20 ° C) while heating using a desktop electromagnetic heating stirrer. After observing the appearance and judging that it was uniformly dissolved, about 100 ml of the homogeneous solution was transferred to a heat-resistant glass container (inner diameter: 60 mm × height: 90 mm), and after cooling, it was prepared at room temperature of Examples 1 to 6 and Comparative Example 3, respectively. It is a semi-solid lubricant composition.

Comparative Example 1 does not contain a guanamine compound and an alkaline earth metal salt, which is a test oil composed only of a synthetic cycloalkane of base oil A; and Comparative Example 2 does not contain a guanamine compound, which is a synthetic naphthene and metal of base oil A. The test oil composed of the salt Ca sulfonate is a composition having liquid lubricity at normal temperature. Further, Comparative Example 4 is a commercially available Li grease.

[evaluation method]

Each of Examples 1 to 6 and Comparative Examples 1 to 4 was carried out in the following manner. Evaluation test of lubricant composition (measurement of friction coefficient, etc.). The results are shown in the lower part of Table 2.

(1) SRV test

A ball-on-disk type SRV friction tester according to the ASTM D5706 standard was used. For the ball system, a steel ball of a 10 mm diameter ball bearing made of SUJ-2 was used, and a disk-shaped test piece having a diameter of 24 mm and a thickness of 7.85 mm of SUJ-2 was used for the disk. The surface of the disk was subjected to a grinding process with a roughness (Rz) of 0.45 to 0.65 μm. The friction test was carried out under the conditions of a load of 50 N, an amplitude of 50 Hz, an amplitude of 1 mm, and a temperature of 40 ° C. The static friction coefficient at the beginning of friction and the coefficient of dynamic friction at 15 minutes were measured. After the friction was stopped, the test ball was measured. .

(2) Evaporation test

2 g of each test sample was weighed on a glass culture dish having a diameter of 70 mm to maintain the liquid sample as it was, and the semi-solid sample was uniformly thinned and placed in a high temperature bath at 120 °C. Evaporation loss (% by mass) was obtained from the mass change over 200 hours.

The static friction coefficients of the examples 1 to 6 in the SRV friction test were 0.13 to 0.17, and the dynamic and static friction coefficients were 0.14 to 0.16. The static friction coefficient and the dynamic friction coefficient of each sample were completely equal or almost the same value, and the wear scar diameter was as small as 0.31 to 0.36. Mm is excellent in abrasion resistance.

On the other hand, in the liquid samples at the normal temperature of Comparative Examples 1 and 2 using the base oil A, both the static friction coefficient and the dynamic friction coefficient were 0.16. The wear scar diameter is 0.38 to 0.37 mm, and although it is slightly larger than the example, it is excellent in abrasion resistance. However, Comparative Example 3 using the base oil C and Comparative Example 4 of the general-purpose grease had a static friction coefficient of 0.10 and a dynamic friction coefficient of 0.37, and generally showed a friction coefficient lower than that of the example. The wear scar diameter of the test ball was a low value of 0.36 mm in Comparative Example 3 and 0.45 mm in Comparative Example 4, showing a large abrasion property.

It is understood that the evaporation reductions of Examples 1 to 6 in the semi-solid state are much smaller than those of Comparative Examples 1 to 3. Although the grease of Example 4 was semi-solid, the evaporation loss was the most, and standing at 120 ° C for 200 hours caused the oil to separate from the tackifier.

From the above results, in the examples of the present invention, even a very small amount of lubricant exhibits a high dynamic friction coefficient, is excellent in abrasion resistance, and is not easily evaporated at a high temperature even if it is applied in a film form. A friction film is formed on the sliding portion for a long period of time.

[Industrial availability]

As apparent from the above description, the lubricant composition which is semi-solid at normal temperature according to the present invention forms a thin film state with a very small amount of use, and exhibits not only a high dynamic friction coefficient but also excellent loss resistance and difficulty in evaporation loss. The sliding portion can be lubricated for a long period of time. In particular, the high dynamic friction coefficient can be applied to mechanical systems with transmission components such as gears, conveyor belts, chains, steel cables, rotating shafts, mechanical stepless speed changers, etc., and has excellent wear resistance and little oil leakage and evaporation loss. Phenomenon, so it can be expected to contribute to the long-term use of mechanical systems.

Claims (3)

A lubricant composition for a transmission element mechanism, which is characterized in that it is semi-solid at normal temperature and contains 70 to 93% by mass of Cp 70 or less of at least one hydrocarbon group selected from alkylcycloalkanes and alkylbenzenes. Oil, 2 to 10% by mass of 50 to 400 mgKOH/g of at least one alkaline earth metal salt selected from the group consisting of Ca sulfonate and Ca salicylate, and 5 to 20% by mass of at least one of the following formula (2) A guanamine compound: R ³ -CO-NH-A ¹ -NH-CO-R ⁴ (2) In the formula (2), R ³ and R ⁴ are each independently a saturated or unsaturated chain having 12 to 20 carbon atoms. a hydrocarbon group; A ¹ is selected from the group consisting of alkylene groups having 1 to 10 carbon atoms. The lubricant composition according to claim 1, wherein the guanamine compound represented by the formula (2) is ethylenebisbesamine or ethylenebisstearylamine. The lubricant composition of claim 1 or 2, wherein the transmission mechanism is a hinge or a mechanical stepless transmission.