Environment-friendly railway track grease composition and preparation method thereof

Abstract

The invention discloses an environment-friendly railway track grease composition and a preparation method thereof, and belongs to the field of lubricating grease. The grease composition comprises the following raw materials in parts by weight: 70-85 parts of base oil, 10-25 parts of a thickening agent, 0.1-1 part of an antioxidant, 3-8 parts of an extreme pressure anti-wear agent, 0.3-1 part of an anti-rust agent, 5-8 parts of a solid powder anti-wear agent and 0.2-1.5 parts of an adhesive, the base oil is modified vegetable oil, the modified vegetable oil is mixed oil obtained by transesterification of vegetable oil and methyl alcohol and ester oil and methyl alcohol, and the base oil is mixed oil obtained by transesterification of ester oil and methyl alcohol. The mixed oil comprises a reaction product obtained by transesterification of vegetable oil and methanol, a reaction product obtained by transesterification of ester oil and methanol, unreacted vegetable oil and unreacted ester oil, the acid value of the modified vegetable oil is 0.03 mgKOH / g, and the viscosity of the modified vegetable oil at 100 DEG C is 10-20 mm < 2 > / s. The preparation method provides a direct method and a pre-soap method, and the fat composition is prepared according to different requirements. The grease composition has the characteristics of biodegradation, low-temperature fluidity, rust prevention, water prevention, cost reduction and the like, and is suitable for railway tracks.

Description

Technical Field

[0001] The invention belongs to the field of lubricating grease and relates to an environmentally friendly railway track grease composition and a preparation method thereof. Background Art

[0002] Railway transportation is an important pillar of modern social and economic development, and plays an indispensable role in freight transportation and passenger travel. With the continuous expansion of the railway network and the continuous growth of transportation intensity, higher requirements are placed on the maintenance and upkeep of railway tracks. Among them, the application of rail grease is of great significance in reducing track wear, energy consumption and noise pollution.

[0003] In recent years, with the continuous enhancement of environmental awareness and the popularization of the concept of sustainable development, higher requirements have been put forward for the environmental protection and biodegradability of railway track grease. Although traditional mineral oil-based grease has good lubrication performance, it is difficult to biodegrade and easily causes environmental pollution. Therefore, the development of environmentally friendly and efficient bio-based track grease has become an urgent need of the industry. In addition, different climatic conditions and operating environments also have different performance requirements for track grease. In cold areas, grease needs to have good low-temperature fluidity; in humid environments, it needs to have excellent anti-rust and waterproof properties. Therefore, the development of special track grease suitable for different working conditions is also an important demand of the market. In addition to environmental protection and applicability, the cost of grease is also a focus of railway operators. The development of long-lasting grease can reduce maintenance frequency, reduce labor and material costs, and thus improve operational efficiency. At the same time, by optimizing the formula and production process, reducing the manufacturing cost of grease will also help improve its market competitiveness.

[0004] In general, environmental protection, high efficiency, multi-function and economical and practical are the main demand directions of the current railway track grease market. Only by meeting these demands can we stand out in the increasingly fierce market competition and win the favor of more customers.

[0005] After searching, the patent application document with Chinese patent application number 202010434862.0 and application publication date of November 30, 2021 discloses a composite lithium-based grease for rail lubrication, preparation method and application. The patent discloses that the composite lithium-based grease includes a composite lithium-based thickener, polycarbonate polyurethane, antioxidant, extreme pressure anti-wear agent, rust inhibitor, additive, and base oil; by using polycarbonate polyurethane as a part of the thickener and film-forming agent, it reacts with the composite lithium-based thickener to generate a composite lithium-based grease with high molecular properties. Due to the strong intermolecular cohesion of carbonate bonds, it has a high glass transition temperature and melting point, thereby improving the temperature stability, low-temperature fluidity and transferability of the composite lithium-based grease; in addition, because the carbonate-based structure is relatively symmetrical, the dipole moment is smaller than that of the ether oxygen bond, and the oxidation resistance is extremely strong, the obtained composite lithium-based grease has very good high-temperature oxidation stability, water resistance, adhesion, colloidal stability, extreme pressure anti-wear and other properties. However, this grease is a mineral oil-based grease. On the one hand, it has a great impact on the environment, including water pollution, soil pollution, etc.; on the other hand, mineral oil-based grease has poor biodegradability and is difficult to degrade naturally, causing long-term negative impact on the ecological environment; on the third hand, mineral oil-based grease is easy to decompose in a high temperature environment and loses its lubrication and wear-reducing effects; on the fourth hand, mineral oil-based grease is easy to solidify in a low temperature environment, affecting the lubrication effect; finally, traditional mineral oil-based grease has poor rust resistance and is easy to cause corrosion and damage to the track.

[0006] The Chinese patent application number is 202110467784.9, and the patent application document with the application publication date of July 30, 2021 discloses an ultra-low temperature and high-degradation high-speed rail wheel rim lubricating grease and its preparation method. The components prepared by this patent contain materials with the following mass percentage concentrations: 15-30% high-base calcium sulfonate, 10-35% PAO base oil, 40-60% synthetic ester base oil, 0.2-0.6% n-butanol, 0.2-0.6% acetic acid, 1-3% dodecyl hydroxystearic acid, 0.5-1.5% boric acid and 0.5-1.5% calcium hydroxide. The lubricating grease uses synthetic oil instead of mineral oil, including PAO base oil and synthetic ester base oil, but the two types of synthetic oils used are expensive and not conducive to mass production.

[0007] The Chinese patent application document with the number of 201711429111.4 and the publication date of May 8, 2018 discloses a special long-term anti-corrosion grease for railway track bolts and its preparation method. The grease includes the following components by mass: 75-85 parts of natural vegetable oil, 25-35 parts of polyurea thickener, 3-5 parts of compound antioxidant, 3-5 parts of anti-wear agent, 1-2 parts of anti-fretting additive, and 10-15 parts of nitrogen-containing rust inhibitor; the polyurea thickener is made of compound organic amine and isocyanate; the compound antioxidant includes amine antioxidant and phenolic antioxidant. The grease is prepared by using natural vegetable oil as the base oil, so that the grease has good biodegradability and has comprehensive physical and chemical properties comparable to traditional railway anti-corrosion grease; various additives are added to make the grease have high and low temperature performance, colloidal stability, mechanical stability, anti-wear, anti-fretting, anti-rust and anti-corrosion, water resistance and long-lasting comprehensive performance. However, on the one hand, vegetable oil is easy to oxidize, and it is easy to oxidize when used directly as a grease. More oxidizing additives need to be added for anti-oxidation, which will correspondingly reduce the performance of the grease. On the other hand, vegetable oil is easily affected by temperature and its service life is reduced. Finally, vegetable oil can be used as a lubricant for light load applications, but it needs to be managed and maintained in accordance with certain regulations and recommendations when used, and it needs to be used with caution in heavy load applications, such as grease for rails.

[0008] In summary, we continue to seek a railroad grease that has the characteristics of biodegradability, low-temperature fluidity, rust prevention and water resistance, and cost reduction. Summary of the invention

[0009] 1. Problem to be solved

[0010] In view of the problem that existing biodegradable greases have high costs or performance that needs to be improved, the present invention provides an environmentally friendly railway track grease composition, which achieves the characteristics of biodegradability, low-temperature fluidity, rust prevention and water resistance, and cost reduction by modifying the base oil, optimizing the grease formula, and using less additives. A preparation method of the environmentally friendly railway track grease composition is further provided.

[0011] 2. Technical solution

[0012] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0013] As a first aspect of the present application, the present application provides an environmentally friendly railway track grease composition, the raw materials for its preparation include, by weight: 70 to 85 parts of base oil, 10 to 25 parts of thickener, 0.1 to 1 part of antioxidant, 3 to 8 parts of extreme pressure anti-wear agent, 0.3 to 1 part of rust inhibitor, 5 to 8 parts of solid powder anti-wear agent, 0.2 to 1.5 parts of adhesive, wherein the base oil is modified vegetable oil, the modified vegetable oil is a mixed oil obtained by ester exchange reaction of vegetable oil and ester oil with methanol respectively, the mixed oil comprises the reaction products of ester exchange of vegetable oil and ester oil with methanol respectively and a mixture of unreacted vegetable oil and ester oil, the acid value of the modified vegetable oil is 0.03 mgKOH / g, and the viscosity at 100°C is 10 to 20 mm 2 / s.

[0014] When the above technical solution is adopted, when vegetable oil is used as a grease base oil, although it has environmental advantages such as renewable and biodegradable, it has obvious disadvantages in terms of thermal oxidation stability, low temperature performance, viscosity range, anti-wear performance and cleaning performance; the applicant considers that ester oil can be mixed into vegetable oil as a base oil, but in order to obtain excellent biodegradability, the proportion of vegetable oil in the base oil needs to be large enough, and a small amount of ester oil cannot meet the oil performance indicators. Therefore, the applicant partially mixes vegetable oil and ester oil with methanol for ester exchange reaction, and by changing the position of fatty acids in the glycerol skeleton, the unreacted vegetable oil, ester oil and reaction products are compounded, which helps to change the physical, chemical, functional, oxidative and nutritional properties of fats and oils. This change can optimize the melting point / dropping point, thermal properties, solid fat content and oxidative stability of vegetable oil, thereby broadening its application range, and can also meet the biodegradability.

[0015] Furthermore, the vegetable oil is selected from rapeseed oil, soybean oil, and castor oil, preferably rapeseed oil. Rapeseed oil shows more advantages than soybean oil and castor oil in the field of lubricants due to its excellent lubrication properties, good high temperature resistance, biodegradability and economic renewability. The ester oil is selected from polyol ester and diethylhexyl sebacate.

[0016] Furthermore, the preparation method of the modified vegetable oil is as follows: after removing water from the vegetable oil, methanol and ester oil are added, and under the catalytic action of sodium methoxide, the vegetable oil and methanol undergo an ester exchange reaction, and at the same time, the ester oil and methanol undergo an ester exchange reaction, and after the reaction is completed, the unreacted vegetable oil, ester oil and reaction product are compounded, and the by-products and unreacted methanol in the reaction are removed to obtain the modified vegetable oil.

[0017] In the case of the above technical solution, sodium methoxide is used as a catalyst to accelerate the transesterification reaction. Both ester oils and vegetable oils contain fatty acid esters. Under the action of sodium methoxide, the ester bonds of the fatty acid esters are broken, and the methoxyl group (-OCH3) in methanol combines with the acyl group in the fatty acid ester to form a new ester and the alcohol part (usually glycerol, etc.) in the original fatty acid ester. The general formula of the reaction can be expressed as: Among them, RCOOR1 represents the fatty acid ester in ester oil or vegetable oil, R1OH represents the alcohol part in the original fatty acid ester, and RCOOCH3 is the new ester generated. It should be noted that the excessive amount of methanol, which participates in the reaction and is also the reaction solvent, can fully disperse the reactants (ester oil, vegetable oil and sodium methoxide catalyst), increase the contact opportunities between them, and thus promote the reaction.

[0018] Furthermore, the raw materials and mass fractions involved in the preparation method of the modified vegetable oil are as follows:

[0019]

[0020]

[0021] Preferably, the mixing mass ratio of vegetable oil to ester oil is (4-6):1.

[0022] Furthermore, the reaction temperature of the transesterification is 70-90°C, and the reaction time of the transesterification is 1-3 hours. The preferred temperature and time of the transesterification reaction are 80°C and 2 hours. During the reaction, by-products such as glycerol and methanol polymers will be produced, and some unreacted raw materials will remain after the reaction. Controlling the reaction time and temperature can effectively reduce by-products.

[0023] Furthermore, anhydrous calcium chloride is used to absorb moisture in the vegetable oil; after the ester exchange reaction is completed, diatomaceous earth is added to absorb by-products and unreacted methanol in the reaction to improve the purity of the product; and the calcium chloride and diatomaceous earth that have absorbed moisture in the oil are separated by suction filtration.

[0024] Furthermore, the thickener is a composite lithium calcium base, which includes a mixture of a macromolecular acid lithium calcium soap and a low molecular acid lithium calcium soap, and is obtained by reacting a macromolecular acid and a low molecular acid with lithium hydroxide and calcium hydroxide, respectively, wherein the mass ratio of the macromolecular acid lithium calcium soap to the low molecular acid lithium calcium soap is (2-3): 1. The macromolecular acid is selected from one of dodecyl hydroxystearic acid and stearic acid; the low molecular acid is selected from one of sebacic acid and boric acid.

[0025] Preferably, the raw materials for preparing the thickener include the following components and their proportions: 60% of macromolecular acid, 20% of low molecular weight acid, 17% of lithium hydroxide, and 3% of calcium hydroxide.

[0026] Furthermore, the antioxidant is selected from one or more of dilauryl thiodipropionate, tert-butyl hydroxyanisole, and butylated hydroxytoluene. Preferably, when two or more antioxidants are used in a compound, the components and their proportions are: 30-50% of dilauryl thiodipropionate, 0-50% of tert-butyl hydroxyanisole, and 0-50% of butylated hydroxytoluene.

[0027] Furthermore, the extreme pressure anti-wear agent is selected from one or more of tricresyl phosphate, isobutylene sulfide, and dialkyl dithiocarbamate, preferably, 0-50% of tricresyl phosphate, 0-80% of isobutylene sulfide, and 0-80% of dialkyl dithiocarbamate.

[0028] Furthermore, the rust inhibitor is selected from one or a combination of petroleum barium sulfonate, benzotriazole, and phenoxyacetic acid, preferably, 0-50% of petroleum barium sulfonate, 0-50% of benzotriazole, and 0-50% of phenoxyacetic acid.

[0029] Furthermore, the solid powder anti-wear agent is nano polytetrafluoroethylene with a particle size of 50nm and a specific surface area of ​​10m 2 / g.

[0030] As a second aspect of the present application, in the case of ready-to-use, the present application provides a method for preparing an environmentally friendly railway track grease composition, and the direct method steps are:

[0031] (1) Saponification reaction: dissolving a macromolecular acid and a low molecular acid in a modified vegetable oil, raising the temperature so that the macromolecular acid and the low molecular acid undergo a saponification reaction with calcium hydroxide and lithium hydroxide to obtain macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap, and continuing to raise the temperature to 130° C. to form a mixture A; wherein calcium hydroxide is first added to form macromolecular acid calcium soap and low molecular acid calcium soap, and then lithium hydroxide is added in small amounts multiple times to obtain macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap;

[0032] The modified vegetable oil is added at once, or added in batches before and after the formation of the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap, and mixed;

[0033] (2) Adding additives after cooling: Cooling the mixture A in step (1) to 130-150° C., and then dispersing an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid powder anti-wear agent in the mixture A to obtain a finished fat composition; the cooling is natural cooling, or cooling by adding modified vegetable oil as quenching oil.

[0034] As a possible implementation, the steps of the direct method are:

[0035] (1) Saponification reaction: 40% of the total oil volume of modified vegetable oil is added and heated to 80°C, and macromolecular acid, low molecular acid and calcium hydroxide aqueous solution are added. After stirring for 30 minutes, the temperature of the reactor is controlled at 90-100°C. Since the fatty acid and calcium hydroxide added in the previous step have undergone saponification reaction, the liquid in the reactor changes into a paste-like fluid, and the fluidity becomes poor. In order to ensure that the lithium hydroxide can fully react, the temperature is controlled at 100°C-130°C, and lithium hydroxide aqueous solution is added in small amounts multiple times within 2 hours for saponification reaction. After the water in the reactor evaporates, the temperature is raised to 150°C-180°C, and 30% of modified vegetable oil is added. Then the temperature of the reactor is raised to 210°C;

[0036] (2) Cooling: Turn off the heating, add the remaining modified vegetable oil, and cool the materials in the reactor. During the grease preparation process, rapid cooling after reaching the highest temperature helps to form a specific soap fiber structure, which directly affects the grease's water resistance, high temperature resistance, shear resistance and colloidal stability. Adding grease base oil to cool is also the most common and cost-saving method in production.

[0037] (3) Adding additives: When the temperature drops to 130-150°C, add antioxidant, extreme pressure anti-wear agent, rust inhibitor, adhesive and solid powder anti-wear agent to the reactor under stirring, and continue stirring for 10-20 minutes;

[0038] (4) Grinding: In order to evenly disperse the grease and solid powder anti-wear agent and ensure that the finished product has a good appearance, it is necessary to cool to room temperature and grind it 2 to 5 times with a three-roller grinder to obtain the finished grease.

[0039] The advantages of the direct method are that it simplifies the grease preparation process, improves production efficiency, and has lower production costs; the disadvantages are that it is relatively inadequate in temperature control and oil dissolution.

[0040] As the third aspect of the present application, in order to overcome the defects of the direct method and increase the storage time, manufacturers generally do not directly prepare the finished fat composition for storage. In the case where the finished fat composition needs to be obtained quickly, the present application provides another method for preparing an environmentally friendly railway track fat composition. The steps of the pre-soap method are:

[0041] S1, preparing prefabricated soap: respectively subjecting a macromolecular acid and a low molecular acid to saponification reaction with calcium hydroxide to generate macromolecular acid calcium soap and low molecular acid calcium soap, heating and adding lithium hydroxide in small amounts multiple times, so that the macromolecular acid calcium soap and the low molecular acid calcium soap react with lithium hydroxide to generate macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap respectively;

[0042] S2, dispersing prefabricated soap: heating the modified vegetable oil, and adding the macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap obtained in step S1 in the heating process;

[0043] The modified vegetable oil in step S2 is added all at once or in portions. During the addition in portions, the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap obtained in step S1 are first dispersed in part of the modified vegetable oil, and then the modified vegetable oil is added continuously while the temperature is raised, so that the modified vegetable oil and the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap are evenly dispersed.

[0044] S3, adding additives after cooling: cooling the modified vegetable oil after dispersing the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap in step S2, wherein the cooling is natural cooling, or cooling by adding the modified vegetable oil as quenching oil, and when cooling to 130-150° C., adding antioxidant, extreme pressure anti-wear agent, rust inhibitor, adhesive and solid powder anti-wear agent, and dispersing them evenly to obtain a finished fat composition.

[0045] As a possible implementation scheme, the steps of the pre-soap method are:

[0046] S1, preparing prefabricated soap: firstly reacting a macromolecular acid and a low molecular acid with an aqueous solution of calcium hydroxide at 80-90° C., respectively, adding a lithium hydroxide aqueous solution in small amounts and multiple times at 90-100° C. for about 2 hours, and baking at 110-130° C. to prepare prefabricated lithium soap, including macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap;

[0047] S2, dispersing prefabricated soap: mixing 40% of the modified vegetable oil in the total oil with macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap at 70-140°C, preferably adding macromolecular acid lithium calcium soap at 70-110°C, and adding low molecular acid lithium calcium soap to react when the reaction temperature rises to 110-130°C;

[0048] S3, heating to 150-180°C, adding 30% modified vegetable oil, and heating to 210°C;

[0049] S4, cooling: adding the remaining modified vegetable oil as quenching oil, circulating and cooling;

[0050] S5. Add antioxidant, extreme pressure anti-wear agent, rust inhibitor, adhesive and solid powder anti-wear agent at 130-150°C, cool to 120°C, and stir for 10-20 minutes.

[0051] S6. After cooling to room temperature, grind it 2 to 5 times with a three-roll grinder to obtain a finished grease product.

[0052] The advantage of the pre-made soap method is that the quality and purity of the soap can be controlled more accurately, because the soap is prepared in advance under specific conditions, while reducing the complex and variable influencing factors in the preparation process and improving the repeatability of the operation. It is particularly suitable for synthetic ester oils that will hydrolyze in an alkaline water environment.

[0053] 3. Beneficial effects

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] (1) Environmentally friendly and biodegradable: The environmentally friendly composite lithium-based grease for railway tracks of the present invention adopts modified vegetable oil as the main component. The modified vegetable oil has good biodegradability and can be naturally degraded without causing long-term negative impact on the environment. It solves the problem of poor biodegradability of mineral oil-based grease and has a greater impact on the environment, including water pollution, soil pollution, etc.

[0056] (2) High temperature resistance and low temperature pumpability: Mineral oil-based greases are easily decomposed in high temperature environments and lose their lubrication and wear-reducing effects. The present invention solves the problem of poor high temperature stability of mineral oil-based greases.

[0057] (3) Good low-temperature pumpability: The environmentally friendly composite lithium-based grease for railway tracks of the present invention has good pumpability in low-temperature environments, is not easy to solidify, and can ensure the lubrication effect in low-temperature environments, thus solving the problem of poor low-temperature pumpability of mineral oil-based grease.

[0058] (4) Good extreme pressure and wear resistance: The environmentally friendly composite lithium-based grease for railway tracks of the present invention improves its extreme pressure and wear resistance by adding various compound additives, which can effectively reduce friction and wear, extend the service life of the track, and solve the problem of poor extrusion wear resistance of mineral oil-based grease.

[0059] (5) Good rust resistance: The environmentally friendly composite lithium-based grease for railway tracks of the present invention has good rust resistance, can effectively prevent the tracks from rusting, extend the service life of the tracks, and solve the problem of poor rust resistance of mineral oil-based grease.

[0060] (6) Long service life: The environmentally friendly composite lithium-based grease for railway tracks of the present invention has good comprehensive performance, can provide long-term lubrication and wear reduction effects, extend the service life of the track, and meet the needs of modern railways for high efficiency and long life.

[0061] In general, the environmentally friendly composite lithium-based grease for railway tracks of the present invention is superior to existing mineral oil-based greases in terms of environmental protection, high-temperature stability, low-temperature pumpability, extreme pressure wear resistance, rust resistance and service life, and is a more advanced railway track lubricating material.

[0062] In the raw material preparation stage, the present invention selects high-quality modified vegetable oil and lithium calcium soap to ensure the performance of the composite lithium calcium grease. Through screening and comparative tests of different raw materials, it is found that the use of base oil with a viscosity index greater than 95 can improve the anti-wear performance of the final product by about 15%.

[0063] The thickener is a composite lithium calcium base. Introducing other metal soaps on the basis of the composite lithium base can make up for some of the shortcomings of lithium-based grease while reducing costs. Introducing calcium soap is the most appropriate. Too much calcium hydroxide will cause the performance of the grease to decline or the saponification reaction to fail and not form grease. After many experiments, it was found that the ratio of lithium hydroxide to calcium hydroxide is 5:1, which improves the water resistance and wear resistance of the grease.

[0064] Secondly, in the saponification reaction stage, controlling the reaction temperature and time is the key to ensure that the reaction is fully carried out. This stage is one of the most critical steps in the production of complex lithium-based grease, which directly affects the quality and performance of the final product. The saponification reaction is mainly the reaction of macromolecular acids and low molecular acids with lithium hydroxide and calcium hydroxide. Through precise temperature control and time management, the generation rate of lithium calcium soap can be increased, thereby improving the consistency and stability of the complex lithium calcium-based grease. Studies have shown that within the temperature range of 100°C to 135°C, the reaction time of 1 to 3 hours can make the conversion rate of lithium soap exceed 90%, effectively improving the stability of the product. In addition, the stirring speed also plays an important role in the saponification reaction. The appropriate stirring speed can ensure that the reactants are evenly mixed and further improve the reaction efficiency.

[0065] Finally, in the post-processing stage, by adding appropriate amounts of antioxidants, anti-wear agents and other additives, the performance of the composite lithium-based grease can be further improved to meet the use requirements under different working conditions. DETAILED DESCRIPTION

[0066] The present invention will be further described below in conjunction with embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should belong to the scope of protection of the present invention.

[0067] The environmentally friendly railway track grease composition of the present application is prepared by using raw materials as shown in the following table by weight:

[0068] Table 1 Raw materials used to prepare environmentally friendly railway track grease composition

[0069]

[0070] With the formulation range in Table 1, the obtained environmentally friendly railway track grease composition meets the following results:

[0071] Table 2 Test results of fat compositions obtained from each formulation in Table 1

[0072]

[0073] In a specific embodiment, the base oil is modified vegetable oil. Preferably, the components and their mass fractions are: 25 parts of vegetable oil (taking rapeseed oil as an example), 4 parts of polyol ester, 60 parts of methanol, and 0.5 parts of sodium methoxide.

[0074] The preparation method of the base oil (modified vegetable oil, taking modified rapeseed oil as an example) is as follows: first, anhydrous calcium chloride is added to rapeseed oil to absorb moisture in the oil, methanol, sodium methoxide and polyol ester are added to the rapeseed oil after the moisture is removed, and the reaction is stirred at 80°C for 2 hours. After the reaction is completed, diatomaceous earth is added to absorb by-products in the reaction and unreacted methanol, and the calcium chloride and diatomaceous earth that have absorbed moisture in the oil are separated by suction filtration to obtain modified rapeseed oil as the base oil, which contains unreacted rapeseed oil, polyol ester and ester exchange reaction products, and the acid value thereof is 0.03 mgKOH / g, and the viscosity at 100°C is 10-20 mm 2 / s.

[0075] In the specific embodiments, the preferred formula is used as each embodiment, the difference is that the types of thickeners are different, and the additives are mixed in a variety of proportions, and the mixing ratios are shown in Table 3:

[0076] Table 3 Mass ratio of composite additives in each embodiment

[0077]

[0078] Example 1: Direct method (thickener: dodecyl hydroxystearic acid, sebacic acid, lithium hydroxide, calcium hydroxide)

[0079] Raw material preparation: 75 parts of modified rapeseed oil, 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of dodecyl stearic acid, 3 parts of sebacic acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0080] 40% of the total oil volume of modified vegetable oil is added and heated to 80°C, dodecyl hydroxystearic acid, sebacic acid and calcium hydroxide aqueous solution are added, and after stirring for 30 minutes, the temperature of the reactor is controlled at 90-100°C; lithium hydroxide aqueous solution is added in small amounts and multiple times within 2 hours for saponification reaction, and the temperature is controlled at 100-130°C; after the water in the reactor evaporates, the temperature is raised to 150-180°C, 30% of modified rapeseed oil is added, and then the temperature of the reactor is raised to 210°C; the heating is turned off, the remaining modified rapeseed oil is added, and the materials in the reactor are cooled; when the temperature drops to 150°C, an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent are added to the reactor under stirring conditions, and stirring is continued for 10-20 minutes; after cooling to room temperature, grinding is performed 2-5 times with a three-roll grinder to obtain a finished grease.

[0081] Example 2: Pre-made soap method (thickener: dodecyl hydroxystearic acid, sebacic acid, lithium hydroxide, calcium hydroxide)

[0082] Raw material preparation: 75 parts of modified rapeseed oil, 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of dodecyl stearic acid, 3 parts of sebacic acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0083] 40% of the modified rapeseed oil in the total oil volume is mixed with lithium calcium dodecanoate soap and lithium calcium sebacate soap at 70-140° C., preferably, lithium calcium dodecanoate soap is added at 70-110° C., and lithium calcium sebacate soap is added when the reaction temperature rises to 110-130° C.; the temperature is raised to 150-180° C., 30% of the modified rapeseed oil is added, and the temperature is raised to 210° C.; the remaining modified rapeseed oil is added as quenching oil, and the temperature is circulated and lowered; an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent are added at 130-150° C., the temperature is lowered to 120° C., and stirring is performed for 10-20 minutes; after cooling to room temperature, the grease is ground 2-5 times in a three-roll grinder to obtain a finished grease.

[0084] Example 3: Pre-made soap method (thickener: stearic acid, sebacic acid, lithium hydroxide, calcium hydroxide)

[0085] Raw material preparation: 75 parts of modified rapeseed oil, 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of stearic acid, 3 parts of sebacic acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0086] 40% of the modified rapeseed oil in the total oil volume is mixed with lithium calcium stearate soap and lithium calcium sebacate soap at 70-140°C for reaction, preferably lithium calcium stearate soap is added at 70-110°C, and lithium calcium sebacate soap is added for reaction when the reaction temperature rises to 110-130°C; the temperature is raised to 150-180°C, 30% of the modified rapeseed oil is added, and the temperature is raised to 210°C; the remaining modified rapeseed oil is added as quenching oil, and the temperature is circulated and lowered; an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent are added at 130-150°C, the temperature is lowered to 120°C, and stirring is performed for 10-20 minutes; after cooling to room temperature, the grease is ground 2-5 times in a three-roll grinder to obtain a finished grease.

[0087] Example 4: Pre-made soap method (thickener: dodecyl hydroxystearic acid, boric acid, lithium hydroxide, calcium hydroxide)

[0088] Raw material preparation: 75 parts of modified rapeseed oil, 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of dodecyl stearic acid, 3 parts of boric acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0089] 40% of the modified rapeseed oil in the total oil volume is mixed with lithium calcium dodecanoate soap and lithium calcium borate soap at 70-140° C. for reaction, preferably adding lithium calcium dodecanoate soap at 70-110° C., and adding lithium calcium borate soap for reaction when the reaction temperature rises to 110-130° C.; heating to 150-180° C., adding 30% of the modified rapeseed oil, and heating to 210° C.; adding the remaining modified rapeseed oil as quenching oil, and cyclically cooling; adding an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent at 130-150° C., cooling to 120° C., and stirring for 10-20 minutes; cooling to room temperature, and grinding with a three-roll grinder for 2-5 times to obtain a finished grease.

[0090] Comparative Example 1

[0091] Commercially available railway track grease, special railway track grease sold by Henan Xinxiang Hengxing Technology Co., Ltd.

[0092] Comparative Example 2

[0093] In Comparative Example 2, the base oil is unmodified vegetable oil compounded with ester oil, and the other components are the same as those in Example 2.

[0094] Raw material preparation: 62.5 parts of rapeseed oil, 12.5 parts of polyol ester, 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of dodecyl stearic acid, 3 parts of sebacic acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0095] 40% of the modified rapeseed oil in the total oil volume is mixed with lithium calcium dodecanoate soap and lithium calcium sebacate soap at 70-140° C., preferably, lithium calcium dodecanoate soap is added at 70-110° C., and lithium calcium sebacate soap is added for reaction when the reaction temperature rises to 110-130° C.; the temperature is raised to 150-180° C., 30% of unmodified rapeseed oil is added, and the temperature is raised to 210° C.; the remaining unmodified rapeseed oil is added as quenching oil, and the temperature is circulated and lowered; an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent are added at 130-150° C., the temperature is lowered to 120° C., and stirring is performed for 10-20 minutes; after cooling to room temperature, the grease is ground 2-5 times in a three-roll grinder to obtain a finished grease.

[0096] Comparative Example 3

[0097] Raw material preparation: 75 parts of base oil (excluding ester oil participating in ester exchange), 2.5 parts of lithium hydroxide, 0.3 parts of calcium hydroxide, 9 parts of dodecyl stearic acid, 3 parts of sebacic acid, 1 part of rust inhibitor, 1 part of antioxidant, 3 parts of extreme pressure anti-wear agent, 5 parts of solid anti-wear agent, and 0.2 parts of adhesive.

[0098] In Comparative Example 3, the modified vegetable oil used as the base oil does not contain any ester oil, and is entirely rapeseed oil. The remaining components are the same as those in Example 2.

[0099] The preparation method of the base oil in Comparative Example 3 is as follows: first, anhydrous calcium chloride is added to rapeseed oil to absorb moisture in the oil, methanol and sodium methoxide are added to the rapeseed oil after the moisture is removed, and the reaction is stirred at 80° C. for 2 hours. After the reaction is completed, diatomaceous earth is added to absorb by-products in the reaction and unreacted methanol, and the calcium chloride and diatomaceous earth that have absorbed moisture in the oil are separated by suction filtration to obtain the base oil of this comparative example, which contains unreacted rapeseed oil and a reaction product of the ester exchange between rapeseed oil and methanol, and the acid value thereof is 0.07 mgKOH / g, and the viscosity at 100° C. is 8 to 10 mm 2 / s.

[0100] The preparation method of the comparative fat composition is:

[0101] 40% of the base oil in the total oil volume is mixed with lithium calcium dodecanoate soap and lithium calcium sebacate soap at 70-140°C for reaction, preferably lithium calcium dodecanoate soap is added at 70-110°C, and lithium calcium sebacate soap is added for reaction when the reaction temperature rises to 110-130°C; the temperature is raised to 150-180°C, 30% of the base oil is added, and the temperature is raised to 210°C; the remaining base oil is added as quenching oil, and the temperature is circulated and lowered; antioxidant, extreme pressure anti-wear agent, rust inhibitor, adhesive and solid anti-wear agent are added at 130-150°C, the temperature is lowered to 120°C, and stirring is performed for 10-20 minutes; after cooling to room temperature, the grease is ground 2-5 times in a three-roll grinder to obtain a finished grease.

[0102] Comparative Example 4

[0103] The base oil is a mineral oil with a viscosity similar to that of the modified vegetable oil, and the other components are the same as those in Example 2.

[0104] Raw material preparation: 750g No. 100 industrial white oil, 25g lithium hydroxide, 3g calcium hydroxide, 90g dodecyl stearic acid, 30g sebacic acid, 10g rust inhibitor, 10g antioxidant, 30g extreme pressure anti-wear agent, 50g solid anti-wear agent, and 2g adhesive.

[0105] 40% of the industrial white oil in the total oil volume is mixed with lithium calcium dodecanoate soap and lithium calcium sebacate soap at 70-140°C for reaction, preferably lithium calcium dodecanoate soap is added at 70-110°C, and lithium calcium sebacate soap is added for reaction when the reaction temperature rises to 110-130°C; the temperature is raised to 150-180°C, 30% of the industrial white oil is added, and the temperature is raised to 210°C; the remaining industrial white oil is added as quenching oil, and the temperature is circulated and cooled; an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid anti-wear agent are added at 130-150°C, the temperature is lowered to 120°C, and stirring is performed for 10-20 minutes; after cooling to room temperature, the grease is ground 2-5 times in a three-roll grinder to obtain a finished grease.

[0106] The test parameters of the fat composition of each embodiment and each comparative example are shown in Table 3 below.

[0107] Table 3 Performance test of fat compositions obtained in various embodiments and comparative examples

[0108]

[0109] As can be seen from the table, the grease prepared by selecting dodecanedioic acid, sebacic acid, lithium hydroxide and calcium hydroxide as the thickener composition has the best performance and meets the requirements of economy and environmental protection; the railway track grease prepared by using modified vegetable oil in the present invention can meet the use requirements in all indicators, and the extreme pressure anti-wear property, high temperature resistance and low temperature pumpability are higher than those of the commercially available product (Comparative Example 1), and the biodegradability is particularly outstanding. Among them, in Comparative Example 2, vegetable oil and ester oil are compounded without modification by methanol ester exchange, and the dropping point, viscosity and extreme pressure performance are all insufficient; in Comparative Example 3, only vegetable oil and methanol ester exchange are used, and the dropping point and viscosity are relatively poor; the grease compositions of each embodiment are environmentally friendly and degradable while meeting the use requirements and achieving high performance, and are particularly suitable as environmentally friendly grease for railway tracks.

[0110] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art. The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent transformation made to the above embodiments according to the technical essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An environmentally friendly railway track grease composition, characterized in that: The raw material composition includes, by weight: 70 to 85 parts of base oil, 10 to 25 parts of thickener, 0.1 to 1 part of antioxidant, 3 to 8 parts of extreme pressure anti-wear agent, 0.3 to 1 part of rust inhibitor, 5 to 8 parts of solid powder anti-wear agent, and 0.2 to 1.5 parts of adhesive, wherein the base oil is modified vegetable oil, and the modified vegetable oil is a mixed oil obtained by transesterification of vegetable oil and ester oil with methanol, respectively. The mixed oil contains the reaction products of transesterification of vegetable oil and ester oil with methanol, respectively, and the unreacted vegetable oil and ester oil are mixed, and the acid value of the modified vegetable oil is 0.03 mgKOH / g, and the viscosity at 100°C is 10 to 20 mm 2 / s.

2. The environmentally friendly railway track grease composition according to claim 1, characterized in that: The preparation method of the modified vegetable oil is as follows: after removing the water in the vegetable oil, methanol and ester oil are added, and under the catalytic action of sodium methoxide, part of the vegetable oil and methanol undergo ester exchange reaction, and at the same time, part of the ester oil and methanol undergo ester exchange reaction, and after the reaction is completed, the by-products in the reaction and the unreacted methanol are removed to obtain the modified vegetable oil.

3. An environmentally friendly railway track grease composition according to claim 2, characterized in that: In the preparation method of modified vegetable oil, the raw materials and mass fractions involved are:

4. The environmentally friendly railway track grease composition according to claim 3, characterized in that: In the raw materials involved in the preparation method of modified vegetable oil, the mixing mass ratio of vegetable oil to ester oil is (4-6):

1.

5. An environmentally friendly railway track grease composition according to any one of claims 1 to 4, characterized in that: The reaction temperature of the transesterification is 70 to 90° C., and the reaction time of the transesterification is 1 to 3 hours.

6. The environmentally friendly railway track grease composition according to claim 1, characterized in that: The thickener is a composite lithium calcium base, which includes a mixture of macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap, wherein the mass ratio of the macromolecular acid lithium calcium soap to the low molecular acid lithium calcium soap is (2-3):

1.

7. The environmentally friendly railway track grease composition according to claim 6, characterized in that: The macromolecular acid forming the macromolecular acid lithium calcium soap is one of dodecyl hydroxystearic acid and stearic acid; the low molecular acid forming the low molecular acid lithium calcium soap is one of sebacic acid and boric acid.

8. The environmentally friendly railway track grease composition according to claim 1, characterized in that: The antioxidant is selected from one or more of dilauryl thiodipropionate, tert-butyl hydroxyanisole, and butylated hydroxytoluene; The extreme pressure anti-wear agent is selected from one or more of tricresyl phosphate, isobutylene sulfide, and dialkyl dithiocarbamate; The rust inhibitor is selected from one or more of barium petroleum sulfonate, benzotriazole, and phenoxyacetic acid; The solid powder anti-wear agent is nano polytetrafluoroethylene.

9. A method for preparing an environmentally friendly railway track grease composition, characterized in that: The method is prepared by using the raw materials in the environmentally friendly railway track grease composition according to claim 6, and the steps are: (1) Saponification reaction: dissolving a macromolecular acid and a low molecular acid in a modified vegetable oil, raising the temperature so that the macromolecular acid and the low molecular acid undergo a saponification reaction with calcium hydroxide and lithium hydroxide to obtain macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap, and continuing to raise the temperature to 210° C. to form a mixture A; wherein calcium hydroxide is first added to form macromolecular acid calcium soap and low molecular acid calcium soap, and then lithium hydroxide is added in small amounts multiple times to obtain macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap; The modified vegetable oil is added at once, or added in batches before and after the formation of the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap, and mixed; (2) Adding additives after cooling: Cooling the mixture A in step (1) to 130-150° C., and then dispersing an antioxidant, an extreme pressure anti-wear agent, a rust inhibitor, an adhesive and a solid powder anti-wear agent in the mixture A to obtain a finished fat composition; the cooling is natural cooling, or cooling by adding modified vegetable oil as quenching oil.

10. A method for preparing an environmentally friendly railway track grease composition, characterized in that: The method is prepared by using the raw materials in the environmentally friendly railway track grease composition according to claim 6, and the steps are: S1, preparing prefabricated soap: respectively subjecting a macromolecular acid and a low molecular acid to saponification reaction with calcium hydroxide to generate macromolecular acid calcium soap and low molecular acid calcium soap, heating and adding lithium hydroxide in small amounts multiple times, so that the macromolecular acid calcium soap and the low molecular acid calcium soap react with lithium hydroxide to generate macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap respectively; S2, dispersing prefabricated soap: heating the modified vegetable oil, and adding the macromolecular acid lithium calcium soap and low molecular acid lithium calcium soap obtained in step S1 in the heating process; The modified vegetable oil in step S2 is added all at once or in portions. During the addition in portions, the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap obtained in step S1 are first dispersed in part of the modified vegetable oil, and then the modified vegetable oil is added continuously while the temperature is raised, so that the modified vegetable oil and the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap are evenly dispersed. S3, adding additives after cooling: cooling the modified vegetable oil after dispersing the macromolecular acid lithium calcium soap and the low molecular acid lithium calcium soap in step S2, wherein the cooling is natural cooling, or cooling by adding the modified vegetable oil as quenching oil, and when cooling to 130-150° C., adding antioxidant, extreme pressure anti-wear agent, rust inhibitor, adhesive and solid powder anti-wear agent, and dispersing them evenly to obtain a finished fat composition.

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