CN111100736B - Lubricating grease composition and preparation method thereof - Google Patents

Abstract

The invention relates to the field of lubricating grease, and discloses a lubricating grease composition and a preparation method thereof. The lubricating grease composition contains base oil, a thickening agent, an organic calcium salt and an auxiliary additive, wherein the total base number of the organic calcium salt is more than or equal to 150mg KOH/g; the auxiliary additive contains organic molybdenum, thiadiazole derivatives and phosphate ester in a weight ratio of 1:0.02-50: 0.02-50. The method comprises the following steps: mixing the thickening agent and part of the base oil, heating, mixing with the rest of the base oil, cooling, and mixing with the organic calcium salt and the auxiliary additive. The lubricating grease composition disclosed by the invention has excellent wear resistance and durability, and after the lubricating grease composition runs for 8 hours in a four-ball machine method wear resistance test, the wear resistance is still about 0.4mm, and the friction coefficient is less than 0.08.

Description

Grease composition and preparation method thereof

technical field

The present invention relates to the field of grease, in particular, to a grease composition and a preparation method thereof.

Background technique

With the development of economy, higher requirements are put forward for the precision, work efficiency, higher frequency of use, long life characteristics, and low maintenance of mechanical equipment. Therefore, lubricating materials are required to have better anti-wear durability . If the wear is caused by poor lubrication, it will directly affect the accuracy of the mechanical equipment, damage the equipment, reduce the service life, and cause economic losses.

In order to improve the antiwear properties of greases, it is usually necessary to add antiwear additives. For example, CN106906030A, adding dibenzyl disulfide (T322), tricresyl phosphate (T306), phosphate ester (T451), boron phosphoamine ester (T3011), etc., the wear diameter of the grease (four-ball method 392N, 60min) is 0.42mm; CN106497652A, adding organic molybdenum, thiophosphate, phosphate ester, the wear diameter of the grease (four-ball method 392N, 60min) is 0.40mm; CN106867637A, adding complex lithium base grease 80-90%, anti-wear lubricant additive 3 -10%, 1-5% polytetrafluoroethylene, 1-5% zinc oxide, 2-14% organic molybdenum and 0.1-3% zinc dialkyldithiosulfate (ZDDP), the _PB value of the grease 981N; CN101889019A, adding thiadiazole poly(ether) glycol complex, molybdenum dihydrocarbyl dithiophosphate, and zinc hydrocarbyl dithiophosphate, the minimum wear diameter of the grease (four-ball method 392N, 60min) is 0.44mm; CN1222594C, adding 0.5%～5% molybdenum sulfide dialkyldithiocarbamate, 0.1%～5% 5,5'-dithiobis(1,3,4-thiadiazole-2-thiol) ), 0.1%-5% of triphenyl phosphorothioate; CN1322104C, adding 1-4% by weight of organic molybdenum, 0.1-5% by weight of sulfur-containing additives, 0.1-5% by weight of phosphorus-containing additives; CN106590846A, Add 0.5% to 5% of molybdenum carbamate, zinc dithiocarbamate, sulfurized olefin, triphenyl phosphate, polytetrafluoroethylene, tricresyl phosphate, melamine cyanurate and the like.

According to the scheme proposed in the above literature, adding the above additives can improve the anti-wear performance of the grease, but it cannot meet the requirements of the anti-wear durability of the grease. will drop significantly, and it is difficult to maintain around 0.4mm.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a grease composition with good anti-wear performance, especially excellent anti-wear durability under long-term conditions (8h), and a preparation method thereof.

In order to achieve the above object, in the first aspect, the present invention provides a grease composition, the grease composition contains a base oil, a thickening agent, an organic calcium salt and auxiliary additives, wherein the total base of the organic calcium salt is The value is ≥150 mg KOH/g; the auxiliary additive contains organic molybdenum, thiadiazole derivatives and phosphoric acid ester in a weight ratio of 1:0.02-50:0.02-50.

In the second aspect, the present invention provides a method for preparing the above-mentioned lubricating grease composition, the method comprising: mixing a thickener and a part of the base oil, heating to increase the temperature, mixing with the remaining base oil, cooling down, and then mixing with an organic calcium salt mixed with auxiliary additives.

In a third aspect, the present invention provides a grease composition prepared by the above method.

Through the above technical solutions, the lubricating grease composition of the present invention exhibits excellent anti-wear durability, and after running for 8 hours in the four-ball machine anti-wear performance test, the anti-wear performance is still about 0.4 mm (measured by the four-ball wear scar diameter) And the friction coefficient is less than 0.08.

Other features and advantages of the present invention will be described in detail in the detailed description that follows.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

In the first aspect, the grease composition provided by the present invention contains a base oil, a thickening agent, an organic calcium salt and an auxiliary additive, wherein the total base number of the organic calcium salt is ≥150 mg KOH/g; the auxiliary additive contains Organomolybdenum, thiadiazole derivative and phosphate ester in a weight ratio of 1:0.02-50:0.02-50.

According to the present invention, the purpose of the present invention can be achieved as long as the auxiliary additives contain the above proportions of organo-molybdenum, thiadiazole derivatives and phosphoric acid esters, but preferably, the organo-molybdenum, thiadiazole derivatives and phosphoric acid esters are among the The weight ratio between them is 1:0.15-6:0.15-6, more preferably 1:0.7-2:0.7-2.

According to the present invention, the organo-molybdenum can be various oil-soluble organo-molybdenum compounds common in the art, for example, molybdenum dialkyldithiophosphate, molybdenum dialkyldithiocarbamate, molybdenum amine complex, Molybdenum alkanoate and molybdenum alkyl salicylate, etc. Preferably, the organic molybdenum is molybdenum dialkyldithiocarbamate (MoDTC) and/or molybdenum dialkyldithiophosphate (MoDTP). The number of carbon atoms of the alkyl group or cycloalkyl group in the above-mentioned organo-molybdenum can be 1-6, for example, the alkyl group in the organo-molybdenum can be methyl, ethyl, propyl, etc., and the molybdenum naphthenate can be a ring Molybdenum hexaformate, etc.

According to the present invention, the thiadiazole derivatives are various common substances with thiadiazole as the parent structure, especially that the thiol hydrogen on the thiadiazole is substituted (for example, by a group having 5-12 carbon atoms) group substituted), the thiadiazole derivative is 2,5-bis(tert-dodecyldithio)-1,3,4-thiadiazole and/or 2,5-bis(tertiary -Octyldithio)-1,3,4-thiadiazole.

According to the present invention, the phosphoric acid ester includes orthophosphoric acid ester and/or phosphite ester, and refers to the ester derivatives of phosphoric acid and/or phosphorous acid. Preferably, the phosphoric acid ester is di-n-butyl phosphite, triphosphoric acid At least one of phenyl ester and tricresyl phosphate.

According to the present invention, the content of the auxiliary additive may be conventionally selected, preferably, based on the total weight of the lubricating grease composition, the content of the auxiliary additive is 0.3-15 wt %, more preferably 0.9-5.5 wt % weight%.

According to the present invention, there is no special requirement for the content of the organic calcium salt, preferably, based on the total weight of the grease composition, the content of the organic calcium salt is 0.1-5 wt %, more preferably 1.5-4.5% by weight.

According to the present invention, the organic calcium salt can be a common organic acid calcium salt and/or calcium phenate, as long as its total base number meets the above requirements. According to a preferred embodiment of the present invention, the total base number of the organic calcium salt is in the range of 150-500 mgKOH/g. In the present invention, the test standard of "total base number" is: SH/T 0251 "Determination of base number of petroleum products (perchloric acid potentiometric titration)", which means to neutralize all alkalinity in 1g sample (organic calcium salt) The amount of perchloric acid required for the component, expressed in milligrams of potassium hydroxide equivalents.

Wherein, the calcium salt of the organic acid can be a substance in which the carboxyl hydrogen in the organic acid is replaced by calcium, for example, the organic acid can be at least one of petroleum sulfonic acid, naphthenic acid and salicylic acid; calcium phenate can be For example, the phenol may be an alkylphenol, wherein the hydroxyl hydrogen of the phenol is replaced by calcium. Preferably, the organic calcium salt is at least one of calcium petroleum sulfonate (such as TBN150, TBN400), calcium alkylphenol (such as TBN200), calcium naphthenate (such as TBN250) and calcium salicylate (such as TBN300). A sort of.

According to the present invention, the content and type of the base oil are not particularly limited, but preferably, based on the total weight of the lubricating grease composition, the content of the base oil is 82-95% by weight, more It is preferably 83-93% by weight.

According to the present invention, the base oil may be various base oils used in lubricating greases, such as mineral oil, synthetic oil (olefin oil and/or ester oil), vegetable oil or a mixture thereof. Preferably, the base oil is a grease with a kinematic viscosity at 100°C of 4-100 mm ² /s. In the present invention, "kinematic viscosity" is measured with reference to GB/T265-1988.

According to the present invention, there is no special requirement for the content of the thickening agent, but preferably, based on the total weight of the grease composition, the content of the thickening agent is 3-10% by weight.

According to the present invention, the thickening agent can be a metal soap commonly used in the art, such as lithium soap and/or sodium soap, preferably, the thickening agent is lithium soap, especially lithium 12-hydroxystearate soap.

According to the present invention, the grease composition may further contain auxiliary agents such as rust inhibitor, oily agent and antioxidant. Among them, antioxidants can further improve the antioxidant properties of the grease composition, thereby prolonging its service life, and can be aromatic amine antioxidants, such as diphenylamine, phenyl-α-naphthylamine and diisooctyldiphenylamine at least one of them. The antioxidant may be present in an amount of 0.01 to 5% by weight, based on the total weight of the grease composition.

The oily agent can further improve the lubricating performance of the surface of the friction pair, and can be higher fatty acids (such as oleic acid, stearic acid), higher alcohols (such as stearyl alcohol), alkyl amines (such as benzotriazole stearylamine) and the like. The oily agent may be included in an amount of 0.01 to 4.5% by weight based on the total weight of the grease composition.

The rust inhibitor can further improve the rust resistance of the grease composition, and can be at least one of barium petroleum sulfonate, sodium petroleum sulfonate, benzothiazole, benzotriazole, zinc naphthenate and alkenylsuccinic acid. A sort of. The rust inhibitor may be present in an amount of 0.01-4.5% by weight, based on the total weight of the grease composition.

In the second aspect, the method for preparing the lubricating grease composition provided by the present invention includes: mixing a thickening agent and a part of the base oil, heating and heating, then mixing with the remaining base oil, cooling down, and then mixing with organic calcium salt and Auxiliary additive mixing.

More specifically, the method includes: mixing the thickener and the first part of the base oil and heating to 200-210°C, then mixing with the remaining base oil, cooling to 100-110°C, and then mixing with the organic acid calcium and Auxiliary additives (and optional auxiliaries such as rust inhibitors, oiliness agents, and antioxidants) are mixed. Generally, the finally obtained mixture should also be ground to make the material disperse more uniformly.

In a third aspect, the present invention provides a grease composition prepared by the above method.

The present invention will be described in detail below by means of examples, but the present invention is not limited thereby. In the following examples and comparative examples, the thickening agent used is 12-hydroxystearic acid lithium soap, and the preparation method is: in water, add 12-hydroxystearic acid and heat it to melt, gradually add an aqueous solution of lithium hydroxide , stir to make it fully react, control the molar ratio of 12-hydroxystearic acid and lithium hydroxide to 1:1, and dry the reactant to obtain 12-hydroxystearic acid lithium soap; other raw material manufacturers and codes used See Table 1 below.

Table 1

Examples 1-12 and Comparative Examples 1-14

According to the proportioning shown in Table 2-4 respectively (accounting for the weight ratio of the total weight of the lubricating grease composition), in the reactor, add about 1/3 base oil and thickening agent, heat up and gradually add about 1/3 3 base oil, the temperature rises to 205 ℃, the remaining base oil is added, the material is cooled and cooled, when the temperature drops to 105 ℃, the organic calcium salt and auxiliary additives are gradually added, and the material is ground by three rounds of grinding to make the material evenly dispersed, A sample of the grease composition was prepared.

The physicochemical properties of the obtained lubricating grease composition samples were analyzed according to the following methods:

Penetration (0.1mm, 60 times): GB/T 269-1991, the smaller the penetration after 60 times of work, the stronger the thickening ability;

Dropping point: GB/T 3498-2008, the higher the dropping point, the better the high temperature performance;

Anti-wear performance: SH/T 0204 "Determination of Anti-wear Performance of Lubricating Grease (Four-Ball Machine Method)", the setting condition of the four-ball testing machine is the load of 392N, and the four-ball wear scar diameter (mm) is measured at the running time of 1h and 8h respectively;

的公式计算摩擦系数，其中，T为摩擦力矩，P为轴向试验力(392N)，R为钢球半径(6.35mm)。Coefficient of friction (μ): The friction torque was measured with the aid of a four-ball testing machine and determined according to

The formula for calculating the friction coefficient, where T is the friction torque, P is the axial test force (392N), and R is the steel ball radius (6.35mm).

The results are shown in Table 2-4.

Table 2

table 3

Table 4

Comparative Example 15

The grease composition was prepared according to the method of Example 1, except that the organic molybdenum was replaced with zinc dithiocarbamate (VanlubeAZ, purchased from Vanderbilt). The results of physical and chemical property analysis are shown in Table 5.

Comparative Example 16

The grease composition was prepared according to the method of Example 1, except that the thiadiazole derivative was replaced with dibenzyl disulfide. The results of physical and chemical property analysis are shown in Table 5.

Comparative Example 17

The grease composition was prepared according to the method of Example 1, except that the phosphate ester was replaced with zinc dibutyldithiophosphate. The results of physical and chemical property analysis are shown in Table 5.

Comparative Example 18

The grease composition was prepared according to the method of Example 4, except that the organic calcium salt was replaced with barium petroleum sulfonate (purchased from Nanjing Runyou Chemical), and the results of physical and chemical performance analysis are shown in Table 5.

table 5

It can be seen from the above examples and comparative examples that the present invention significantly improves the anti-wear durability of the grease composition by mixing specific types of components in specific ratios, and only by mixing each component in the application can the anti-wear properties be effectively improved. Grinding durability.

Furthermore, further experiments have shown that the grease composition of the present invention exhibits superior antiwear durability compared to existing grease compositions (as the respective greases mentioned in the background), even in antiwear Running for 8h in the grinding performance test can also keep the diameter of the four-ball wear scar at about 0.4mm.

The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the specific technical features described in the above-mentioned specific embodiments can be combined in any suitable manner unless they are inconsistent. In order to avoid unnecessary repetition, the present invention provides The combination method will not be specified otherwise.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

Claims (10)

1. The lubricating grease composition is characterized by comprising base oil, a thickening agent, organic calcium salt and an auxiliary additive, wherein the thickening agent is lithium soap; the total base number of the organic calcium salt is more than or equal to 150mg KOH/g; the auxiliary additive contains organic molybdenum, thiadiazole derivatives and phosphate ester in a weight ratio of 1:0.7-50: 0.7-50; based on the total weight of the grease composition, the content of the organic calcium salt is 0.1-5 wt%, and the content of the auxiliary additive is 0.3-15 wt%.

2. Grease composition according to claim 1, wherein the weight ratio between the organomolybdenum, the thiadiazole derivative and the phosphate ester is 1:0.7-2: 0.7-2.

3. A grease composition according to claim 1 or 2, wherein the organomolybdenum is molybdenum dialkyldithiocarbamate and/or molybdenum dialkyldithiophosphate;

and/or the thiadiazole derivative is 2, 5-di (tert-dodecyl-dithio) -1,3, 4-thiadiazole and/or 2, 5-di (tert-octyl-dithio) -1,3, 4-thiadiazole;

and/or the phosphate ester is at least one of di-n-butyl phosphite, triphenyl phosphate and tricresyl phosphate.

4. Grease composition according to claim 1 or 2, wherein the auxiliary additive is present in an amount of 0.9 to 5.5 wt.%, based on the total weight of the grease composition.

5. Grease composition according to claim 1 or 2, wherein the organic calcium salt is present in an amount of 1.5-4.5 wt.%, based on the total weight of the grease composition.

6. Grease composition according to claim 1, wherein the organic calcium salt is at least one of calcium petroleum sulfonate, calcium alkyl phenate, calcium naphthenate and calcium salicylate.

7. Grease composition according to claim 1, wherein the base oil is present in an amount of 82-95 wt.%, based on the total weight of the grease composition; the content of the thickening agent is 3-10 wt%.

8. A grease composition according to claim 1 or 7, wherein the base oil has a kinematic viscosity at 100 ℃ of 4-100mm ² /s。

9. A method of preparing a grease composition according to any one of claims 1-8, characterized in that the method comprises: mixing the thickening agent with part of the base oil, heating, mixing with the rest base oil, cooling, and mixing with the organic calcium salt and the auxiliary additive.

10. A grease composition made by the process of claim 9.