Environmentally friendly micro-nano particle modified biodegradable lubricating grease and preparation method thereof

Abstract

The present invention relates to the field of lubricating greases, specifically to an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease and a preparation method thereof. The lubricating grease comprises the following raw materials, by weight: 23-28 parts of modified vegetable oil, 5-7 parts of modified nanocellulose, 6-9 parts of a thickener, 0.8-1.3 parts of an antioxidant, and 0.4-0.9 parts of a tackifier. The lubricating grease provided by the present invention has a wide applicable temperature range, good low-temperature fluidity, a high degradation rate, and excellent impact resistance and high-load resistance.

Description

Technical Field

[0001] The present invention relates to the field of lubricating grease, and in particular to an environmentally friendly micro-nano particle modified biodegradable lubricating grease and a preparation method thereof. Background Art

[0002] Because shield machines use a centralized oil supply method, sealing lubricants must be continuously injected to maintain normal operation. This results in a significant amount of lubricant consumption. Common sealing lubricant products on the market are mostly made with mineral oil as the base oil component, compounded with industrial fibers. These products are rich in oil-derived components and are directly discharged into the natural environment after use. This has a low environmental degradation rate. Underground working environments and construction conditions are limited, and impurities present in these greases make recycling shield tunneling equipment lubricants difficult, resulting in significant material waste and pollution of the soil and water environment. Therefore, improving the biodegradability of products and reducing their environmental impact is a top priority.

[0003] Patent CN111303960B provides a self-repairing lubricant composed of the following ingredients: iron oxide powder, copper oxide powder, graphite powder, metallic zinc powder, carbon black micron particles, metallic aluminum powder, and metallic silver powder. Using HVIWH150 as a base oil, in addition to conventional lubrication, it can achieve a self-repairing effect under extreme pressure conditions. Patent CN101473019B discloses a lubricant grease composition comprising: base oil, urea compound, phosphorus compound, and fatty acid metal salt. When applied to the surface of a sliding pair consisting of metal and plastic parts, it can significantly extend the durability of the part. Most existing technologies use base oils that are difficult to degrade, without considering the problem of environmental pollution caused by discharge into soil or water.

[0004] Therefore, there is an urgent need for an environmentally friendly biodegradable lubricating grease. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides an environmentally friendly biodegradable lubricating grease with a wide applicable temperature range, good low-temperature fluidity, and excellent impact resistance and high-load resistance.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease, which comprises the following raw materials, by weight: 23-28 parts of modified vegetable oil, 5-7 parts of modified nanocellulose, 6-9 parts of thickener, 0.8-1.3 parts of antioxidant, and 0.4-0.9 parts of viscosity enhancer.

[0008] In some embodiments, the preparation of the modified vegetable oil comprises the following steps:

[0009] (1) Add formic acid and hydrogen peroxide into a reaction vessel, add sulfuric acid while stirring, and stir at a constant temperature of 35-45°C for 2-3 hours to obtain an epoxidizing agent;

[0010] (2) adding vegetable oil to a container and heating it to 40-50° C., adding the epoxidizing agent obtained in step (1) while stirring, and completing the addition within 0.9-1.2 hours, continuing to stir at a constant temperature for 4.5-5.5 hours, standing to separate, washing, and distilling to obtain epoxidized vegetable oil;

[0011] (3) Add cyclopropylmethylamine to the epoxidized vegetable oil obtained in step (2), stir at a constant temperature of 75-85° C. for 3.5-4.5 hours, then add acetic acid, react for 3.5-4.5 hours, and dry to obtain modified vegetable oil.

[0012] Preferably, the concentration of the hydrogen peroxide is 28-32 wt %.

[0013] More preferably, the concentration of the hydrogen peroxide is 30 wt %.

[0014] Preferably, the mass ratio of formic acid to hydrogen peroxide is 1:(4.7-5.3).

[0015] Further preferably, the mass ratio of formic acid to hydrogen peroxide is 1:4.9.

[0016] Preferably, the vegetable oil is industrial soybean oil.

[0017] In some embodiments, the mass ratio of the vegetable oil to the epoxidizing agent in step (2) is (2.6-3):1.

[0018] In some embodiments, the mass ratio of epoxidized vegetable oil, cyclopropylmethylamine and acetic acid in step (3) is (11.2-12.8):(1-1.2):1.

[0019] Vegetable oils have the advantages of being green and renewable, environmentally compatible, non-volatile, easy to degrade, and highly lubricating, and are often used to synthesize bio-based lubricants. However, because vegetable oils contain a large number of carbon-carbon double bonds, they are extremely susceptible to oxidation and deterioration. In addition, the unique triglyceride structure of vegetable oils is unstable and easily decomposed at high temperatures, which greatly limits the direct use of natural vegetable oils as lubricants. The applicant has improved the low-temperature fluidity and thermal stability of vegetable oil by changing its chemical structure. In the present invention, an epoxidizing agent with good epoxy performance is prepared by controlling the mass ratio of formic acid and hydrogen peroxide. By controlling the mass ratio of vegetable oil and epoxidizing agent, some carbon-carbon double bonds in the vegetable oil are epoxidized, and then the ring is opened with amine. The mass ratio of epoxidized vegetable oil, cyclopropylmethylamine and acetic acid is controlled so that the epoxidized vegetable oil can be completely ring-opened, thereby improving its low-temperature fluidity. This may be due to the large steric hindrance of amine. The amine with large steric hindrance on the side chain can reduce the mutual connection of normal alkanes in the molecule under low temperature conditions, forming a stable three-dimensional network structure, which greatly improves the low-temperature fluidity of the vegetable oil. At the same time, the double bonds are still present, and its oxidative stability is not destroyed. In addition, the modified vegetable oil can coordinate with the metal ions in the lubrication part of the shield machine to form a stable five-membered ring or six-membered ring structure, which increases the adhesion ability of the lubricating grease in the lubrication part and reduces wear.

[0020] In some embodiments, the preparation method of the modified nanocellulose is: adding nanocellulose to a reaction vessel, then adding ethanol and stirring, heating to 75-85°C, then adding a silane coupling agent, continuing to stir at a constant temperature for 1.5-2.5 hours, then adding p-hydroxystyrene and an initiator, reacting at 60-70°C for 1-2 hours, cooling to room temperature, and drying to obtain modified nanocellulose.

[0021] Preferably, the particle size of the nanocellulose is 3-10 nm.

[0022] In some embodiments, the mass ratio of the nanocellulose, the silane coupling agent, and the p-hydroxystyrene is 1:(0.08-0.12):(1-2).

[0023] Preferably, the mass ratio of the nanocellulose, the silane coupling agent and the p-hydroxystyrene is 1:0.1:1.5.

[0024] Preferably, the silane coupling agent is a silane coupling agent containing a double bond.

[0025] Nanocellulose is a renewable and biodegradable material that can be mass-produced without causing environmental pollution. When added to lubricating grease, it can effectively reduce the amount of lubricant used and reduce costs. It can also increase the mechanical properties and heat resistance of the lubricated parts, improve the surface properties of the material, and extend the life of the material. However, due to the small particle size of nanocellulose, the particles have huge surface energy, and the attraction between the particles causes a large tendency for the particles to automatically aggregate, making it difficult to disperse evenly in vegetable oil. The present invention uses a silane coupling agent to modify the surface of nanocellulose, reducing the attraction between the particles and making it easier to disperse. At the same time, it has good compatibility with vegetable oil. The diameter is large, so that after the lubricated parts are squeezed and collided, the nanocelluloses form a whole, which increases the wear reduction and high load capacity of the lubricating grease. In addition, a silane coupling agent containing double bonds is specifically selected to further react with p-hydroxystyrene. The modified nanocellulose has a phenolic hydroxyl structure to further improve the oxidation resistance of the lubricating oil. Moreover, the modified nanocellulose does not need to be post-processed after preparation, which reduces the preparation steps. By limiting the mass ratio of nanocellulose, silane coupling agent, and p-hydroxystyrene, some double bonds can still remain in the modified nanocellulose, which reacts with modified industrial soybean oil to increase its branched structure, which can further improve the low-temperature fluidity of the vegetable oil without reducing its oxidation resistance.

[0026] In some embodiments, the thickener is a fatty acid metal salt.

[0027] Preferably, the thickener is any one or more of magnesium stearate, aluminum stearate, zinc stearate, calcium stearate, and 12-hydroxy calcium stearate.

[0028] More preferably, the thickener is aluminum stearate.

[0029] In the present invention, fatty acid metal salt is used as a thickener and is dispersed in the base oil to form a structural skeleton of the grease, so that the base oil is adsorbed and fixed in the structural skeleton.

[0030] In some embodiments, the antioxidant is any one or more of 2,6-di-tert-butyl-p-cresol, 2,4,6-tri-tert-butylphenol, eicosyl diphenol phosphate, tetracosylphenol phosphate, and eicosyl acetal.

[0031] Preferably, the antioxidant is 2,6-di-tert-butyl-p-cresol.

[0032] In some embodiments, the tackifier is any one or more of polyurethane, terpene resin, and alkylphenol-formaldehyde resin.

[0033] Preferably, the tackifier is a terpene resin.

[0034] The second aspect of the present invention provides a method for preparing an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease, the preparation method comprising the following steps: placing modified vegetable oil and modified nanocellulose in a kneader, kneading at 65-75°C for 20-30 minutes, continuing to add a thickener, an antioxidant, and a tackifier and continuing to knead at 40-50°C for 25-35 minutes to obtain an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. The present invention epoxidizes some of the carbon-carbon double bonds in the vegetable oil and then performs ring opening with an amine. The mass ratio of the epoxidized vegetable oil, cyclopropylmethylamine, and acetic acid is controlled so that the epoxidized vegetable oil can be completely ring-opened, thereby improving its low-temperature fluidity.

[0037] 2. The modified vegetable oil of the present invention can coordinate with the metal ions in the lubricating parts of the shield machine to form a stable five-membered ring or six-membered ring structure, thereby increasing the adhesion of the lubricating grease to the lubricating parts and reducing wear;

[0038] 3. The present invention uses a specific silane coupling agent and p-hydroxystyrene to modify the surface of nanocellulose, thereby reducing the attraction between particles and facilitating dispersion. At the same time, it improves compatibility with vegetable oils, increases the wear resistance and high load capacity of lubricating greases, and the modified nanocellulose can further improve the low-temperature fluidity and oxidation resistance of vegetable oils. DETAILED DESCRIPTION

[0039] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples and comparative examples are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0040] In order to facilitate those skilled in the art to implement the present invention, some of the raw materials and manufacturers of the embodiments and comparative examples are described as follows:

[0041] In the following examples and comparative examples, except for modified industrial soybean oil and modified nanocellulose, the other compounds and related reagents used can be purchased from the market. Industrial soybean oil was purchased from Guangzhou Hequan Trading Co., Ltd.; nanocellulose was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. with a particle size of 3-10 nm; and terpene resin was purchased from Shandong Defeng Industry and Trade Co., Ltd. with a relative density of 0.95-1.0.

[0042] Preparation Example 1

[0043] The preparation method of modified industrial soybean oil-1 comprises the following steps:

[0044] (1) Add 9.2 g of formic acid and 45.08 g of 30 wt% hydrogen peroxide into a reaction vessel, add 1.5 ml of 85 wt% sulfuric acid while stirring, and stir at 40° C. for 2.5 h to obtain an epoxidizing agent;

[0045] (2) 28 g of industrial soybean oil was added to a container and heated to 45° C. 10 g of the epoxidizing agent obtained in step (1) was added while stirring at a rotation speed of 150 r / min. The addition was completed within 1 h. The container was stirred at a constant temperature for 5 h. The container was allowed to stand for stratification. The upper layer was washed with a 0.1 mol / L sodium carbonate solution to a pH of 5, and then washed with saturated salt water and deionized water until neutral. The container was distilled under reduced pressure to obtain epoxidized industrial soybean oil.

[0046] (3) Add 1.1 g of cyclopropylmethylamine to 12 g of epoxidized industrial soybean oil obtained in step (2), stir at a constant temperature of 80° C. for 4 h, then add 1 g of acetic acid, react for 4 h, and dry to obtain modified industrial soybean oil.

[0047] Preparation Example 2

[0048] The specific implementation method of the preparation method of modified industrial soybean oil-2 is the same as that of Preparation Example 1, except that 24g of industrial soybean oil is added in step (2).

[0049] Preparation Example 3

[0050] The specific implementation method of the preparation method of modified industrial soybean oil-3 is the same as that of Preparation Example 1, except that 10 g of epoxidized industrial soybean oil is added in step (3).

[0051] Preparation Example 4

[0052] The preparation method of modified nanocellulose-1 is as follows: 6 g of nanocellulose is added to a reaction container, 100 g of anhydrous ethanol is added and stirred, the temperature is raised to 80°C, 0.6 g of silane coupling agent KH570 is added, and the stirring is continued at a constant temperature for 2 hours. Then, 9 g of p-hydroxystyrene and 0.16 g of azobisisobutyronitrile are added, the reaction is carried out at 65°C for 1.5 hours, the mixture is cooled to room temperature, and dried to obtain modified nanocellulose-1.

[0053] Preparation Example 5

[0054] The preparation method of modified nanocellulose-2 is the same as that of Preparation Example 4, except that 4 g of p-hydroxystyrene is added.

[0055] Example 1

[0056] Disclosed is an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease, comprising the following raw materials, by weight: 25 parts of modified industrial soybean oil-1, 6 parts of modified nanocellulose-1, 7 parts of aluminum stearate, 1 part of 2,6-di-tert-butyl-p-cresol, and 0.6 parts of terpene resin.

[0057] In this embodiment, a method for preparing an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease comprises the following steps: placing modified industrial soybean oil-1 and modified nanocellulose-1 in a kneader, kneading at 70°C for 25 minutes, continuously adding aluminum stearate, 2,6-di-tert-butyl-p-cresol, and terpene resin, and continuing to knead at 45°C for 30 minutes to obtain an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease.

[0058] Example 2

[0059] Disclosed is an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease, comprising the following raw materials, by weight: 23 parts of modified industrial soybean oil-1, 5 parts of modified nanocellulose-1, 6 parts of aluminum stearate, 0.8 parts of 2,6-di-tert-butyl-p-cresol, and 0.4 parts of terpene resin.

[0060] The preparation method of the environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease of this embodiment includes the following steps: modifying industrial soybean oil-1 and modified nanocellulose-1 in a kneader, kneading them at 75°C for 20 minutes, continuously adding aluminum stearate, 2,6-di-tert-butyl-p-cresol, and terpene resin, and continuing to knead them at 50°C for 25 minutes to obtain the environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease.

[0061] Example 3

[0062] Disclosed is an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease, comprising the following raw materials, by weight: 28 parts of modified industrial soybean oil-1, 7 parts of modified nanocellulose-1, 9 parts of aluminum stearate, 1.3 parts of 2,6-di-tert-butyl-p-cresol, and 0.9 parts of terpene resin.

[0063] The preparation method of the environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease of this embodiment includes the following steps: modifying industrial soybean oil-1 and modified nanocellulose-1 in a kneader, kneading at 65°C for 30 minutes, continuously adding aluminum stearate, 2,6-di-tert-butyl-p-cresol, and terpene resin, and continuing to knead at 40°C for 35 minutes to obtain the environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease.

[0064] Example 4

[0065] This embodiment provides an environmentally friendly micro-nanoparticle modified biodegradable lubricating grease and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified industrial soybean oil-1 is replaced by modified industrial soybean oil-2 of equal weight.

[0066] Example 5

[0067] This embodiment provides an environmentally friendly micro-nanoparticle modified biodegradable lubricating grease and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified industrial soybean oil-1 is replaced by modified industrial soybean oil-3 of equal weight.

[0068] Example 6

[0069] This embodiment provides an environmentally friendly micro-nanoparticle modified biodegradable lubricating grease and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified nanocellulose-1 is replaced by modified nanocellulose-2 of equal weight.

[0070] Comparative Example 1

[0071] This comparative example provides an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the modified industrial soybean oil-1 is replaced by industrial soybean oil of the same weight.

[0072] Comparative Example 2

[0073] This comparative example provides an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that modified nanocellulose-1 is replaced by nanocellulose of equal weight.

[0074] Performance testing:

[0075] 1. Freezing point

[0076] The pour point of the environmentally friendly micro-nano particle modified biodegradable lubricating grease prepared in each embodiment and comparative example was tested with reference to GB / T510.

[0077] 2. Degradability

[0078] The environmentally friendly micro-nanoparticle-modified biodegradable lubricating greases prepared in the examples and comparative examples were subjected to rapid biodegradation and inherent biodegradation according to GB / T21801 and GB / T21818.

[0079] 3. Stability

[0080] The environmentally friendly micro-nanoparticle-modified biodegradable lubricating greases prepared in the examples and comparative examples were left to stand for 3 months and then subjected to a pour point test again.

[0081] The test results are shown in Table 1.

[0082] Table 1

[0083]

[0084]

[0085] From the comparison of the experimental data of Examples 1-3 in Table 1, it can be seen that by changing the ratio of the components in the raw materials, the environmentally friendly micro-nanoparticle modified biodegradable lubricating grease still has a low pour point, degradability and stability; in Example 4, modified industrial soybean oil-2 is used. Due to the reduction in the amount of industrial soybean oil added, a large amount of double bonds in the industrial soybean oil may be oxidized, resulting in an increase in the pour point; in Example 5, modified industrial soybean oil-3 is used. It may be due to the reduction in the mass of the epoxidized soybean oil that cyclopropylmethylamine and acetic acid do not react fully, and the purity of the modified industrial soybean oil decreases, resulting in an increase in the pour point after standing and a decrease in stability; in Example 6, modified nanocellulose-2 is used, and the amount of p-hydroxystyrene added is reduced, which may lead to a decrease in the antioxidant property of the modified nanocellulose, thereby increasing the pour point; in Comparative Example 1, industrial soybean oil is used. Industrial soybean oil contains a large number of carbon-carbon double bonds, which leads to a high pour point of the lubricating grease and is easily oxidized and deteriorated; in Comparative Example 2, nanocellulose with a particle size of 3-10 nm is used, which may result in an increase in the pour point of the lubricating grease, a decrease in biodegradability, and a deterioration in stability due to a decrease in dispersibility in the lubricating oil.

[0086] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly micro-nanoparticle modified biodegradable lubricating grease, characterized in that: The invention comprises the following raw materials in parts by weight: 23-28 parts of modified vegetable oil, 5-7 parts of modified nanocellulose, 6-9 parts of thickener, 0.8-1.3 parts of antioxidant, and 0.4-0.9 parts of viscosity enhancer; The preparation of the modified vegetable oil comprises the following steps: (1) Add formic acid and hydrogen peroxide into a reaction vessel, add sulfuric acid while stirring, and stir at a constant temperature of 35-45°C for 2-3 hours to obtain an epoxidizing agent; (2) adding vegetable oil to a container and heating it to 40-50° C., adding the epoxidizing agent obtained in step (1) while stirring, and completing the addition within 0.9-1.2 hours, continuing to stir at a constant temperature for 4.5-5.5 hours, standing to separate, washing, and distilling to obtain epoxidized vegetable oil; (3) adding cyclopropylmethylamine to the epoxidized vegetable oil obtained in step (2), stirring at a constant temperature of 75-85° C. for 3.5-4.5 hours, then adding acetic acid, reacting for 3.5-4.5 hours, and drying to obtain a modified vegetable oil; In the step (2), the mass ratio of the vegetable oil to the epoxidizing agent is (2.6-3):1; In the step (3), the mass ratio of epoxidized vegetable oil, cyclopropylmethylamine and acetic acid is (11.2-12.8): (1-1.2): 1; The modified nanocellulose preparation method comprises: adding nanocellulose to a reaction vessel, adding ethanol and stirring, heating to 75-85° C., adding a silane coupling agent, continuing to stir at a constant temperature for 1.5-2.5 hours, then adding p-hydroxystyrene and an initiator, reacting at 60-70° C. for 1-2 hours, cooling to room temperature, and drying to obtain the modified nanocellulose; The mass ratio of the nanocellulose, the silane coupling agent and the p-hydroxystyrene is 1:(0.08-0.12):(1-2).

2. The environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease according to claim 1, characterized in that: The thickener is a fatty acid metal salt.

3. The environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease according to claim 1, characterized in that: The antioxidant is any one or more of 2,6-di-tert-butyl-p-cresol, 2,4,6-tri-tert-butylphenol, eicosyl diphenol phosphate, tetracosylphenol phosphate, and eicosyl acetal.

4. The environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease according to claim 1, characterized in that: The tackifier is any one or more of polyurethane, terpene resin, and alkylphenol-formaldehyde resin.

5. A method for preparing an environmentally friendly micro-nanoparticle-modified biodegradable lubricating grease according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: placing modified vegetable oil and modified nanocellulose in a kneader, kneading at 65-75°C for 20-30 minutes, adding a thickener, an antioxidant, and a tackifier, and kneading at 40-50°C for 25-35 minutes to obtain an environmentally friendly micro-nano particle modified biodegradable lubricating grease.

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