CN111635803A

CN111635803A - Long-life fluorine-containing lubricating grease for bearings and preparation method thereof

Info

Publication number: CN111635803A
Application number: CN202010609720.3A
Authority: CN
Inventors: 李倩; 乔姣飞; 辛虎
Original assignee: China Petroleum and Chemical Corp
Current assignee: China Petroleum and Chemical Corp
Priority date: 2020-06-29
Filing date: 2020-06-29
Publication date: 2020-09-08

Abstract

The invention provides long-life fluorine-containing bearing grease and a preparation method thereof, and solves the technical problems that common grease cannot run at high temperature for a long time, fluorine grease is very high in price, and lubrication fails due to large temperature rise of a bearing in the prior art. The long-life fluorine-containing lubricating grease for bearings provided by the invention comprises the following components in percentage by weight: 50-80% of polyurea prefabricated soap; 10% -30% of perfluoropolyether base oil; 5% -15% of a thickening agent; 1-5% of antiwear extreme pressure additive; the antiwear extreme pressure additive is one or a combination of more of nano calcium carbonate, sulfurized olefin, tricresyl phosphate, chlorinated paraffin, silicon dioxide, molybdenum disulfide, molybdenum dialkyl dithiophosphate sulfurized oxymolybdenum, zinc diisooctyl dithiophosphate and dialkyl dithiocarbamate.

Description

Long-life fluorine-containing lubricating grease for bearings and preparation method thereof

Technical Field

The invention belongs to the field of lubricating materials, and particularly relates to long-life fluorine-containing lubricating grease for a bearing and a preparation method thereof.

Background

With the expansion of bearing applications and the advancement of bearing technologies, miniaturization, high rotational speed, long service life, precision, low noise, and the like become important directions for the development of bearing technologies. Grease is referred to as the fifth major element of the bearing. When the bearing is operated in a high-temperature and high-speed environment, the grease inside the bearing is subjected to severe tests, which puts higher demands on the performance of the bearing grease.

The prior art has conducted a great deal of research on bearing greases. The polyurea lubricating grease has the characteristics of long service life, high temperature resistance, low noise and excellent bearing temperature rise performance, is called as 'new-generation efficient lubricating grease', and is one of lubricating grease varieties with development prospects. CN102899125A discloses a preparation method of polyurea lubricating grease with excellent shearing performance, which can be used for lubricating equipment such as high-speed motor bearings, steel mill continuous casting machine bearings, automobile constant-speed universal joints, precision instruments and meters. This patent obtains polyurea greases having excellent shear properties. CN102585970B discloses polyurea-based lubricating grease with high mechanical stability and a preparation method thereof. The polyurea lubricating grease is novel high-temperature lubricating grease prepared from urea compound thickened base oil, and the urea compound is an oxidation inhibitor and has no catalytic aging effect on the base oil, so that the polyurea lubricating grease has good high-temperature resistance, but can be used under the high-temperature condition of 180-200 ℃ in a short time, and when the polyurea lubricating grease is operated at high temperature for a long time, the bearing is easily worn to be aggravated, and the service life of the bearing is shortened. The prepared polyurea lubricating grease cannot meet the long-time high-temperature operation of the bearing.

CN108715768A discloses a perfluoropolyether lubricating grease for a long-life high-temperature bearing, a preparation method and application thereof, and the perfluoropolyether lubricating grease prepared by the patent can be used at a high temperature of more than 300 ℃ for a long time. The perfluoropolyether lubricating grease prepared by using the perfluoropolyether oil as the base oil has excellent heat resistance and corrosion resistance, but the high-temperature fluorine lubricating grease has high price and large bearing temperature rise and is not suitable for the high-speed high-load working condition of the bearing.

Disclosure of Invention

In view of the above, the invention provides long-life fluorine-containing bearing grease and a preparation method thereof. The long-life fluorine-containing lubricating grease for the bearing solves the technical problems that common lubricating grease cannot run at a high temperature for a long time, fluorine lubricating grease is very high in price, the temperature rise of the bearing is large, lubrication is failed and the like in the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

the invention provides long-life bearing fluorine-containing lubricating grease which comprises the following components in percentage by weight:

50-80% of polyurea prefabricated soap;

10% -30% of perfluoropolyether base oil;

5% -15% of a thickening agent;

1-5% of antiwear extreme pressure additive;

the antiwear extreme pressure additive is one or a combination of more of nano barium carbonate, sulfurized olefin, tricresyl phosphate, chlorinated paraffin, silicon dioxide, molybdenum disulfide, molybdenum oxysulfide of dialkyl dithiophosphate, zinc diisooctyl dithiophosphate and dialkyl dithiocarbamate.

In some embodiments, the polyurea pre-soap is selected from one or more combinations of 7014 high temperature grease, 7014-1 high temperature grease, 7014-3 high temperature grease, 7035-1 bearing grease, 7019-1 extreme pressure high temperature grease; the polyurea preformed soap may be a commercially available product.

In some embodiments, the perfluoropolyether base oil is a linear perfluoropolyether oil having the formula CF₃-O-(CF₂-CF₂-O)_m-(CF₂-O)_n-CF₃Wherein m and n are integers between 1 and 500; the molecular weight of the perfluoropolyether base oil is 10000-20000 g/mol, preferably 15000-20000 g/mol.

In some embodiments, the thickener is selected from one or more of polytetrafluoroethylene, chlorotrifluoroethylene-polyethylene, tetrafluoroethylene-hexafluoropropylene copolymer.

In some embodiments, the thickener is a powder having an average particle size of 0.01 to 80 μm.

Some examplesIn one embodiment, the thickener has a molecular weight of 1 × 10⁴～1×10⁹g/mol, preferably 1 × 10⁵～1×10⁸g/mol。

The invention also provides a preparation method of the long-life bearing fluorine-containing lubricating grease, which comprises the following steps:

1) stirring and mixing the polyurea prefabricated soap and the perfluoropolyether base oil to obtain a mixture;

2) adding the thickening agent into the mixture obtained in the step 1), and continuously stirring;

3) adding the antiwear extreme pressure additive into the mixture obtained in the step 2), and stirring to obtain a uniform mixture;

4) carrying out ultrasonic treatment on the mixture obtained in the step 3) in a water bath ultrasonic device;

5) repeatedly grinding the mixture subjected to the ultrasonic treatment in the step 4) in a three-roll grinder for 2-5 times.

In some embodiments, the stirring in step 1) to step 3) is performed under vacuum, and the stirring time is 0.5-2h, respectively, and the vacuum stirring speed is 100-3000 r/min.

In some embodiments, in step 4), the temperature of the sonication is 50 to 70 ℃ and the sonication time is 0.5 to 2 hours.

The technical scheme provided by the invention has the following beneficial effects:

the invention takes perfluoropolyether oil with excellent chemical stability, thermal stability and flame retardancy as base oil, adds polyurea prefabricated soap and powder thickening agent, simultaneously adds anti-wear extreme pressure additive, and fully grinds by a three-roller grinder to prepare the lubricant. The lubricating grease obtained by mutually matching and combining the components according to a specific proportion has the following beneficial effects:

(1) the lubricating grease can be applied to high-speed and high-load bearings, is excellent in wear resistance and extreme pressure performance, and can ensure long-life bearing lubrication.

(2) Based on perfluoropolyether oil and a thickening agent, the polyurea prefabricated soap and the anti-wear extreme pressure additive are matched and combined according to a specific proportion, the long-life fluorine-containing bearing lubricating grease has outstanding chemical stability, thermal stability, flame retardancy and the like, and is suitable for working conditions under severe conditions.

(3) The preparation method of the lubricating grease is simple and easy to operate, and is suitable for industrial production.

Detailed Description

In order that the technical features and contents of the present invention can be understood in detail, preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention have been described in the examples, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.

< sources of raw materials >

Perfluoropolyether oils (i.e., perfluoropolyether base oils) of the formula CF₃-O-(CF₂-CF₂-O)_m-(CF₂-O)_n-CF₃Wherein the values of m and n are respectively 92 and 100, the molecular weight is 17426g/mol, the Beijing division of China petrochemical lubricating oil company is 145-165 ℃/0.3 mmHg;

7014 high temperature grease, Chongqing division of China petrochemical lubricating oil company;

7014-1 high temperature grease, Chongqing division of China petrochemical lubricating oil Co;

7014-3 high temperature grease, Chongqing division of China petrochemical lubricating oil corporation;

7035-1 bearing grease, Chongqing division of petrochemical lubricating oil, China;

7019-1 extreme pressure high temperature grease, Chongqing Branch of China petrochemical lubricating oil company;

tetrafluoroethylene-hexafluoropropylene copolymer, Shandong Yue Shenzhou, DS611, purity 99%, molecular weight 1 × 10⁷～5×10⁷g/mol; the average particle size was 50 μm.

Polytetrafluoroethylene, Japan gold, L-5F, having an average particle diameter of 0.520 μm and a molecular weight of 5 × 10⁶～6×10⁶g/mol；

Chlorotrifluoroethylene-polyethylene copolymer, Dongguan, XM220, average particle size 50 μm, molecular weight 3 × 10⁷～1×10⁸g/mol；

Nanometer calcium carbonate, Shanghai Polyqian New Material development Co., Ltd., particle size 60-80 nm;

molybdenum dialkyl dithiophosphate sulfide, analytically pure, Nanjing Eporui nanomaterial Co., Ltd., particle size of 0.1-15 μm;

sulfurized olefin, Wuhan Xinkang fine chemical, purity 99%;

tricresyl phosphate, yokohama yarui chemical industry;

chlorinated paraffin, Yingtai chemical industry, purity 99%;

silicon dioxide, chemical industry in the sunny day of Jinan, and the particle size is 20 mu m;

molybdenum disulfide, Dingqianuo, 2000 mesh granularity and 99% purity;

dialkyl dithiocarbamate, new Shandong Liang material, particle size 0.2-10 μm;

diisooctyl dithiophosphate zinc salt antioxidant corrosion inhibitor, analytically pure, tin-free south petroleum additive limited.

< test methods >

The sample without the additive is taken as a comparative example, the sample with the additive added in different proportions is taken as an example, and the modification performance of the sample is respectively tested and compared. Specific test items are as follows: penetration, steel mesh oil separation, evaporation loss, sintering load and bearing temperature rise. The test procedure adopted the following method criteria:

(1) the penetration test of the lubricating grease is referred to the GB/T3498-2008;

(2) the steel mesh oil separation test is referred to standard SH/T0324;

(3) evaporative loss test reference standard GB/T7325;

(4) sintering load test reference standard SH/T0202

(5) The bearing temperature rise test is in reference to the standard GB/T32321.

In the above test items, the steel mesh oil separation can indicate the colloidal stability of the grease, the evaporation loss can indicate the high-temperature stability of the grease, and the sintering load can indicate the anti-wear extreme pressure performance of the grease. As is well known in the art, according to K15 rule, the temperature of the bearing or friction part and the change amplitude have obvious influence on the lubricating effect and the service life of the grease, and the service life of the grease is reduced by about 1/2 when the temperature of the bearing rises by 10-15 ℃ in terms of the relationship between the temperature of the bearing and the service life of the grease. Bearing temperature rise can indicate the service life of the grease.

Example 1

(1) 1kg of 7014 high-temperature lubricating grease and 600g of perfluoropolyether base oil are placed in a stirrer, and stirring is started for 2 hours at a stirring speed of 1500r/min to obtain a uniform mixture.

(2) Adding 300g of polytetrafluoroethylene thickening agent into the mixture, and continuously stirring for 0.5h at the normal temperature at the stirring speed of 1500 r/min.

(3) Adding 100g of nano calcium carbonate into the mixture, continuously stirring for 0.5h at the normal temperature at the stirring speed of 1500r/min, and stirring to obtain a uniform mixture.

(4) Performing ultrasonic treatment in a water bath ultrasonic instrument at 50 ℃ for 2 h.

(5) And (3) repeatedly grinding the mixture subjected to the ultrasonic treatment in a three-roll grinder for 4 times to obtain the long-life fluorine-containing bearing grease.

Example 2

(1) 1.4kg of 7014-1 high-temperature lubricating grease and 340g of perfluoropolyether base oil are placed in a stirrer, and stirring is started for 0.5h at the stirring speed of 1000r/min to obtain a uniform mixture.

(2) Adding 100g of chlorotrifluoroethylene-polyethylene thickening agent into the mixture, and continuously stirring for 0.5h at the normal temperature and the stirring speed of 1000 r/min.

(3) Adding 60g of molybdenum dialkyl dithiophosphate sulfide into the mixture, continuously stirring for 0.5h at the normal temperature of 1000r/min, and stirring to obtain a uniform mixture.

(4) Performing ultrasonic treatment in a water bath ultrasonic instrument at 70 deg.C for 0.5 h.

(5) And (3) repeatedly grinding the mixture subjected to the ultrasonic treatment in a three-roll grinder for 3 times to obtain the long-life fluorine-containing bearing grease.

Example 3

(1) 1.4kg of 7014-1 high-temperature lubricating grease and 400g of perfluoropolyether base oil are placed in a stirrer, and stirring is started for 2 hours at a stirring speed of 3000r/min to obtain a uniform mixture.

(2) Adding 140g of polytetrafluoroethylene thickening agent into the mixture, and continuously stirring for 0.5h at the normal temperature at the stirring speed of 3000 r/min.

(3) Adding 60g of zinc diisooctyl dithiophosphate into the mixture, continuously stirring for 0.5h at the normal temperature of 3000r/min, and stirring to obtain a uniform mixture.

(5) And (3) repeatedly grinding the mixture subjected to the ultrasonic treatment in a three-roll grinder for 5 times to obtain the long-life fluorine-containing bearing grease.

Comparative example 1 (No antiwear extreme pressure additive compared to example 3)

(2) Adding 200g of polytetrafluoroethylene thickening agent into the mixture, and continuously stirring for 0.5h at the normal temperature at the stirring speed of 3000 r/min.

(3) Performing ultrasonic treatment in a water bath ultrasonic instrument at 70 deg.C for 0.5 h.

(4) And (3) repeatedly grinding the mixture subjected to the ultrasonic treatment in a three-roll grinder for 5 times to obtain the long-life fluorine-containing bearing grease.

Comparative example 2 (comparison with example 3, no Polyuret prefabricated soap)

(1) 1.34kg of perfluoropolyether base oil and 460g of polytetrafluoroethylene thickening agent are placed in a stirrer, and stirring is started for 2 hours at the stirring speed of 3000r/min to obtain a uniform mixture.

(2) Adding 200g of zinc diisooctyl dithiophosphate into the mixture, continuously stirring for 0.5h at the normal temperature of 3000r/min, and stirring to obtain a uniform mixture.

Comparative example 3 (No perfluoropolyether base oil and powder thickener compared to example 3)

(1) 1.94kg of 7014-1 high-temperature lubricating grease and 60g of zinc diisooctyl dithiophosphate are put into a stirrer, and stirred for 2 hours at a stirring speed of 3000r/min to obtain a uniform mixture.

(2) Performing ultrasonic treatment in a water bath ultrasonic instrument at 70 deg.C for 0.5 h.

(3) And (3) repeatedly grinding the mixture subjected to the ultrasonic treatment in a three-roll grinder for 5 times to obtain the long-life fluorine-containing bearing grease.

Example 4

(1) 1.56kg of 7014-1 extreme pressure high temperature grease and 300g of perfluoropolyether base oil are placed in a stirrer, and stirring is started for 2 hours at the stirring speed of 2000r/min to obtain a uniform mixture.

(2) Adding 100g of chlorotrifluoroethylene-polyethylene thickening agent into the mixture, and continuously stirring for 0.5h at the normal temperature at the stirring speed of 2000 r/min.

(3) Adding 40g of silicon dioxide into the mixture, continuously stirring for 0.5h at the normal temperature of 2000r/min, and stirring to obtain a uniform mixture.

(4) Performing ultrasonic treatment in a water bath ultrasonic instrument at the ultrasonic temperature of 60 ℃ for 1 h.

Example 5

(1) 1.5kg of 7019-1 extreme pressure high temperature grease and 300g of perfluoropolyether base oil are placed in a stirrer, and stirring is started for 1h at the stirring speed of 800r/min to obtain a uniform mixture.

(2) Adding 100g of tetrafluoroethylene-hexafluoropropylene copolymer thickening agent into the mixture, and continuously stirring for 1h at the normal temperature at the stirring speed of 800 r/min.

(3) Adding 100g of zinc diisooctyl dithiophosphate into the mixture, continuously stirring for 1h at the normal temperature at the stirring speed of 800r/min, and stirring to obtain a uniform mixture.

(4) Performing ultrasonic treatment in a water bath ultrasonic instrument at the ultrasonic temperature of 70 ℃ for 1 h.

The grease prepared in the above examples and the sample without additive were subjected to the related performance comparison test, and the comparison table of the test results is shown in the following table 1:

TABLE 1 comparative table of the properties of the greases obtained in the above examples with respect to the samples without additives

The following points can be seen from table 1: firstly, a small amount of anti-wear extreme pressure additive is added into the lubricating grease, so that the temperature rise of the bearing can be effectively controlled, and the service life of the fluorine-containing lubricating grease in the bearing is prolonged; secondly, the addition of the polyurea prefabricated soap is beneficial to effectively controlling the temperature rise performance of the bearing by using fluorine-containing lubricating grease to a certain extent; the perfluoropolyether base oil can effectively reduce the evaporation loss of the lubricating grease, and the prepared fluorine-containing lubricating grease has high-temperature condition stability; the fluorine-containing lubricating grease without the antiwear extreme pressure additive has smaller sintering load, and the numerical value of the sintering load is increased when the proper antiwear extreme pressure additive is added. Therefore, the addition of a proper amount of the anti-wear extreme pressure additive can effectively improve the anti-wear extreme pressure performance of the lubricating grease, prolong the service life of the lubricating grease and ensure that the lubricating grease can play a good role in lubricating and sealing in the bearing.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims

1. The long-life fluorine-containing lubricating grease for the bearing is characterized by comprising the following components in percentage by weight:

50-80% of polyurea prefabricated soap;

10% -30% of perfluoropolyether base oil;

5% -15% of a thickening agent;

1-5% of antiwear extreme pressure additive;

the antiwear extreme pressure additive is one or a combination of more of nano calcium carbonate, sulfurized olefin, tricresyl phosphate, chlorinated paraffin, silicon dioxide, molybdenum disulfide, molybdenum dialkyl dithiophosphate sulfurized oxymolybdenum, zinc diisooctyl dithiophosphate and dialkyl dithiocarbamate.

2. The long life fluorine-containing grease for bearings of claim 1, wherein said polyurea preformed soap is selected from one or more of 7014 high temperature grease, 7014-1 high temperature grease, 7014-3 high temperature grease, 7035-1 bearing grease, 7019-1 extreme pressure high temperature grease.

3. The long life bearing fluorogrease of any one of claims 1-2, wherein said perfluoropolyether base oil is a linear perfluoropolyether oil having the formula CF₃-O-(CF₂-CF₂-O)_m-(CF₂-O)_n-CF₃Wherein m and n are integers between 1 and 500; the molecular weight of the perfluoropolyether base oil is 10000-20000 g/mol, preferably 15000-20000 g/mol.

4. Long life bearing fluorogrease according to any of claims 1-3, characterized in that said thickener is selected from one or more of polytetrafluoroethylene, chlorotrifluoroethylene-polyethylene, tetrafluoroethylene-hexafluoropropylene copolymer.

5. The long life bearing fluorogrease of claim 4, characterized in that said thickener has a molecular weight of 1 × 10⁴～1×10⁹g/mol, preferably 1 × 10⁵～1×10⁸g/mol。

6. The long life bearing fluorogrease of any one of claims 1-5, wherein said thickener has an average particle size of 0.01-80 μm.

7. A method of preparing a long life bearing fluorogrease as claimed in any one of claims 1 to 6, comprising the steps of:

8. The method as claimed in claim 7, wherein the stirring in step 1) to step 3) is performed under vacuum, and the stirring time is 0.5-2h, and the vacuum stirring speed is 100-3000 r/min.

9. The method according to claim 7 or 8, wherein the temperature of the ultrasonic treatment in step 4) is 50 to 70 ℃ and the ultrasonic treatment time is 0.5 to 2 hours.