1. The open gear lubricating grease is characterized by being prepared from raw materials comprising base oil, a thickening agent and a structural auxiliary agent, wherein the thickening agent comprises organic bentonite, the structural auxiliary agent comprises fumed silica,

in the raw materials, the mass ratio of the organic bentonite to the fumed silica is (2-5): 1.

2. the open gear grease of claim 1 wherein the organobentonite has a 75 μm dry sieve pass rate of not less than 98% and the silica has a specific surface area of not less than 150m²/g。

3. The open gear grease of claim 1 or 2 wherein the raw materials comprise the following components in parts by weight: 60-80 parts of base oil, 6-9 parts of organic bentonite and 2-3 parts of fumed silica.

4. The open gear grease as claimed in any one of claims 1 to 3, wherein the kinematic viscosity at 40 ℃ of the base oil is 400-600mm²/s；

Preferably, the base oil is prepared from (2-4) by mass: 2 mineral oil 150BS and synthetic oil PAO 40.

5. The open gear grease lubricant according to any one of claims 1 to 4, characterized in that the raw materials further comprise an extreme pressure antiwear agent accounting for 1-3% of the total mass of the raw materials and an antirust agent accounting for 0.5-1%,

the extreme pressure anti-wear agent is a borate extreme pressure anti-wear agent, and the antirust agent is an organic carboxylate antirust agent;

preferably, the borate extreme pressure antiwear agent is borate T361A, and the organic carboxylate antirust agent is barium dinonylnaphthalene sulfonate.

6. The open gear grease of any one of claims 1 to 5 wherein the raw material further comprises a tackifier accounting for 14 to 20 percent of the total mass of the raw material, the tackifier comprises polyisobutylene with a kinematic viscosity at 100 ℃ of 630mm²Has a molecular weight of 950-.

7. The open gear grease lubricant according to any one of claims 1-6, wherein the raw material further comprises an antioxidant which accounts for 0.5-1% of the total mass of the raw material, and the antioxidant is an amine antioxidant;

preferably, the antioxidant is N-phenyl-alpha naphthylamine.

8. The open gear grease of any one of claims 1 to 7, wherein the raw materials further comprise a solid filler accounting for 2 to 6 percent of the total mass of the raw materials, and the solid filler is one or more selected from molybdenum disulfide, graphite and polytetrafluoroethylene;

preferably, the solid filler is molybdenum disulfide.

9. Use of an open gear grease according to any one of claims 1 to 8 in open gear lubrication.

10. The method for preparing an open gear grease of any one of claims 1 to 8, comprising the steps of:

(1) mixing base oil accounting for 50-70% of the total mass of the base oil with organic bentonite, and heating to 80-85 ℃;

(2) mixing the mixed material obtained in the step (1) with the gas-phase silicon dioxide serving as a structural assistant, and continuously stirring for 1-1.5 hours to ensure that the organic bentonite is fully expanded and activated in the base oil;

(3) after the refining in the step (2) is finished, adding the residual base oil and the tackifier;

(4) when the temperature is reduced to below 80 ℃, adding the solid filler, the extreme pressure antiwear agent, the antioxidant and the antirust agent, and continuing to stir for 0.5 to 1 hour;

(5) and (4) homogenizing, filtering and degassing the material obtained in the step (4).

Background

The open gear is a common transmission mode in the raw material processing industry and large-scale surface mining equipment, and is widely applied to large-scale equipment in the industries of mines, cement, power plants, steel, chemical industry, paper making and the like, such as a rotary gear and a pushing gear of an electric shovel in the mine industry, a rotary kiln and a tube mill in the cement industry, a rotary kiln and a sintering kiln in the steel industry and the like. The open gear is mainly characterized in that: heavy load, low speed, larger equipment size, open or semi-closed gear transmission, higher tooth surface roughness and harsher working conditions (high and low temperature, sand wind, impact load and the like are often involved). The conditions of open gear transmission require that the lubricant should have the following properties: 1. the material has excellent high and low temperature performance and is suitable for being applied in a wide temperature environment; 2. the adhesion is good, the oil film is rich, and the oil film is not easy to fall off; 3. the lubricant contains a certain proportion of solid fillers (graphite, molybdenum disulfide) and an extreme pressure additive, and has excellent extreme pressure wear resistance; 4. good pumping performance; 5. the antirust performance is good, and the tooth surface is protected from being corroded by rain and snow; 6. does not contain heavy metal and volatile organic substances, and has no harm to the environment and operators.

Statistically, nearly 20% of gear damage failures are caused by poor lubrication and lubrication failure, so that the selection of a proper lubricant has a very important role in normal operation of the open gear.

CN 102433195 a discloses a grease composition for an open gear, which is made of metal soap grease, vegetable oil, ester oil, polyisobutylene, solid filler, extreme pressure agent, antioxidant and rust inhibitor. CN 104164277A discloses heavy-load open gear grease and a preparation method thereof, and the grease is prepared from a composite aluminum thickener, base oil, an extreme pressure antiwear agent, an oiliness agent, a solid additive, an antirust agent, a tackifier and an antioxidant. Most of the preparation processes of the lubricating grease disclosed by the prior art involve complex chemical reactions, the production process is complex, and the production stability is poor. Therefore, it is urgently needed to provide the open gear lubricating grease with convenient production process and excellent comprehensive performance.

Disclosure of Invention

The invention aims to provide an open gear lubricating grease which has excellent comprehensive performance and simple raw materials and a preparation method. The invention also provides a preparation method of the open gear lubricating grease.

Specifically, the invention provides the following technical scheme:

the invention provides open gear lubricating grease, which is prepared from raw materials comprising base oil, a thickening agent and a structural auxiliary agent, wherein the thickening agent comprises organic bentonite, the structural auxiliary agent comprises fumed silica, and the mass ratio of the organic bentonite to the fumed silica in the raw materials is (2-5): 1.

the invention develops the lubricating grease for the open gear aiming at the characteristics of the working environment of the open gear and the performance requirements of the lubricating grease. In the prior art, the open gear lubricating grease mostly adopts calcium-based, aluminum-based, composite aluminum-based and other soap-based thickeners to meet the performance requirements of open gears on the consistency, adhesiveness and the like of the lubricating grease, but the preparation process of the soap-based thickener lubricating grease is complex and the production efficiency is low. In the research and development process, soap-based thickening agents are tried to be replaced by other thickening agents, but the soap-based thickening agents are simply replaced by other thickening agents, so that the comprehensive performance of the lubricating grease is obviously reduced, and the requirements of an open gear are difficult to meet well. The organic bentonite is used as a thickening agent, and the fumed silica is used as a structural auxiliary agent, so that the problems can be well solved, and the comprehensive performance of the lubricating grease is well ensured while the simplicity and convenience in operation and the production efficiency of the preparation process are improved.

Preferably, the 75 μm dry sieve passing rate of the organobentonite is not less than 98%, and the specific surface area of the silica is not less than 200m²/g。

Although the present invention has the above-mentioned advantages, it has been found that the incorporation of an organobentonite with fumed silica requires the addition of a liquid dispersion aid (e.g., ethanol) in order to sufficiently disperse both in the production system, and that these organic aids are volatile and may reduce the production safety. Through further research and development, the invention discovers that the bentonite with 75 mu m dry sieve passing rate not less than 98 percent and the specific surface area not less than 200m are adopted²The dependency of the preparation raw materials on the liquid dispersing aid can be obviously reduced by the fumed silica per gram.

Preferably, the preparation raw material of the lubricating grease comprises the following components in parts by weight: 60-80 parts of base oil, 6-9 parts of organic bentonite and 2-3 parts of fumed silica.

As the base oil, it is preferable to use a base oil having a kinematic viscosity at 40 ℃ of 400-²/s。

Further preferably, the base oil is prepared from (2-4) by mass: 2 mineral oil 150BS and synthetic oil PAO 40.

The invention discovers that the organic bentonite and the gas-phase silicon dioxide can be well dispersed by adopting the base oil, the organic bentonite is fully expanded, and a liquid dispersing auxiliary agent can not be added into a raw material system.

The preparation raw material of the lubricating grease can also comprise various additives.

Specifically, the raw materials comprise an extreme pressure anti-wear agent and an antirust agent, wherein the extreme pressure anti-wear agent accounts for 1-3% of the total mass of the raw materials, the antirust agent accounts for 0.5-1%, the extreme pressure anti-wear agent is a borate extreme pressure anti-wear agent, and the antirust agent is an organic carboxylate antirust agent.

Preferably, the borate extreme pressure antiwear agent is borate T361A, and the organic carboxylate antirust agent is barium dinonylnaphthalene sulfonate.

The extreme pressure antiwear agent and the antirust agent can be well matched with a raw material system of organic bentonite and fumed silica, the structure of the organic bentonite is not damaged, and meanwhile, excellent extreme pressure antiwear performance and antirust performance are exerted.

Preferably, the raw material also comprises a tackifier accounting for 14-20% of the total mass of the raw material, the tackifier comprises polyisobutylene with the kinematic viscosity at 100 ℃ of 630mm²Has a molecular weight of 950-.

The above-mentioned tackifier can impart suitable viscosity and better adhesion to the grease of the present invention.

Preferably, the raw materials also comprise an antioxidant accounting for 0.5-1% of the total mass of the raw materials, and the antioxidant is an amine antioxidant.

Further preferably, the antioxidant is N-phenyl-alpha naphthylamine.

Preferably, the raw material further comprises solid filler accounting for 2-6% of the total mass of the raw material, and the solid filler is one or more selected from molybdenum disulfide, graphite and polytetrafluoroethylene.

Preferably, the solid filler is molybdenum disulfide.

Preferably, the purity of the molybdenum disulfide is not less than 98.5%.

As a preferable scheme of the invention, the preparation raw materials of the lubricating grease comprise the following components in parts by weight:

35-45 parts of base oil 150BS, 0-30 parts of base oil PAO 402, 6-9 parts of organic bentonite, 2-3 parts of fumed silica, 15-25 parts of polyisobutylene, 2-4 parts of molybdenum disulfide, 2-4 parts of borate T361A 2, 0.5-1.5 parts of N-phenyl-alpha naphthylamine and 0.5-1.5 parts of barium dinonylnaphthalene sulfonate.

The invention provides application of the open gear lubricating grease in open gear lubrication.

The invention further provides a method for preparing the open gear lubricating grease, so that the performances of all components in the formula can be well exerted.

The invention provides a preparation method of open gear grease, which comprises the following steps:

(1) mixing base oil accounting for 50-70% of the total mass of the base oil with organic bentonite, and heating to 80-85 ℃;

(2) mixing the mixed material obtained in the step (1) with the gas-phase silicon dioxide serving as a structural assistant, and continuously stirring for 1-1.5 hours to ensure that the organic bentonite is fully expanded and activated in the base oil;

(3) after the refining in the step (2) is finished, adding the residual base oil and the tackifier;

(4) when the temperature is reduced to below 80 ℃, adding the solid filler, the extreme pressure antiwear agent, the antioxidant and the antirust agent, and continuing to stir for 0.5 to 1 hour;

(5) and (4) homogenizing the material obtained in the step (4), filtering and degassing.

The invention has the beneficial effects that: the open gear lubricating grease disclosed by the invention is convenient to produce, easy to operate and high in production efficiency, avoids the pollution of volatile organic auxiliaries to the environment in the production process, and simultaneously improves the production safety. The open gear lubricating grease has good extreme pressure wear resistance, low temperature fluidity, adhesion and antirust performance, and has excellent comprehensive performance.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The tackifier polyisobutene used in the examples below had a molecular weight of 1300 and a kinematic viscosity at 100 ℃ of 630mm²And s. The 75 μm dry sieve passing rate of the organic bentonite is not less than 98%, and the specific surface area of the silicon dioxide is not less than 150m²/g。

Example 1

The embodiment provides an open gear grease, and the preparation method thereof is as follows:

firstly, 240g of 150BS, 160g of PAO40 and 90g of organobentonite are added into a reaction kettle, fully mixed and stirred, heated to 85 ℃, added with 30g of fumed silica, and continuously stirred for 1 hour to ensure that the organobentonite fully expands and activates in base oil. And after refining, adding 120g of 150BS, 80g of PAO40 and 200g of polyisobutylene in the residual base oil, adding 30g of molybdenum disulfide, 10g of borate T361A 30g, 10g of N-phenyl-alpha naphthylamine and 10g of barium dinonylnaphthalene sulfonate when the temperature is reduced to be below 80 ℃, continuously stirring for 0.5h, rolling for three times by a three-roll mill, degassing, and filtering to obtain the open gear lubricating grease.

Example 2

The embodiment provides an open gear grease, and the preparation method thereof is as follows:

firstly, adding 260g of 150BS, 173g of PAO40 and 75g of bentonite into a reaction kettle, fully mixing and stirring, heating to 85 ℃, adding 25g of fumed silica, and continuing stirring for 1h to ensure that the organic bentonite fully expands and activates in the base oil. After refining, 130g of residual base oil 150BS, 87g of PAO40 and 200g of polyisobutylene are added, 30g of molybdenum disulfide, 10g of borate T361A 30g, 10g of N-phenyl-alpha naphthylamine and 10g of barium dinonylnaphthalene sulfonate are added when the temperature is reduced to be below 80 ℃, the mixture is continuously stirred for 0.5h, and the mixture is rolled for three times by a three-roll mill, degassed and filtered to obtain the open gear lubricating grease.

Example 3

The embodiment provides an open gear grease, and the preparation method thereof is as follows:

firstly, 280g of 150BS, 187g of PAO40 and 60g of bentonite are added into a reaction kettle, fully mixed and stirred, heated to 85 ℃, added with 20g of fumed silica, and continuously stirred for 1 hour to ensure that the organic bentonite fully expands and activates in the base oil. After refining, 140g of 150BS, 93g of PAO40 and 200g of polyisobutylene in the rest base oil are added, 30g of molybdenum disulfide, 10g of borate T361A 30g of N-phenyl-alpha naphthylamine and 10g of barium dinonylnaphthalene sulfonate are added when the temperature is reduced to be below 80 ℃, the mixture is continuously stirred for 0.5h, and the mixture is rolled for three times by a three-roll mill, degassed and filtered to obtain the open gear lubricating grease.

Comparative example 1

This comparative example differs from example 1 in that: fumed silica is not added.

Comparative example 2

This comparative example differs from example 1 in that: the fumed silica was replaced with an equal volume of a 95:5 mixture of ethanol and water.

The open gear greases of examples 1-3, comparative example 1, and comparative example 2 above were tested for performance and the results are shown in table 1.

Table 1 test results for greases

From the experimental results of table 1, it can be seen that:

1. the working penetration of comparative example 1 is significantly higher than example 1, indicating that fumed silica as a structural aid can significantly thicken grease systems.

2. The working cone penetration of comparative example 2 is significantly higher than example 1, indicating that the addition of the liquid structuring agent ethanol is significantly less effective than fumed silica in thickening bentonite grease systems.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.