Extreme-pressure-resistant and high-temperature-resistant composite polyurea lubricating grease and preparation method thereof

Abstract

According to the extreme pressure-resistant and high temperature-resistant composite polyurea lubricating grease and the preparation method thereof disclosed by the invention, silicon dioxide is added into polyurea to form a composite polyurea thickening agent, so that the composite polyurea thickening agent has good extreme pressure property and longer bearing service life at high temperature. The molecular structure of the silicon dioxide-polyurea compound comprises aliphatic groups, aromatic hydrocarbon groups and various polar groups, in micelles, the polar groups in molecules attract each other, silicon dioxide-polyurea molecules form a three-dimensional structural framework in mineral oil, and oil is adsorbed in gaps of the framework to form a stable colloid structure. The extreme-pressure-resistant and high-temperature-resistant composite polyurea lubricating grease prepared by the invention comprises the following raw material components in percentage by mass: 65-80% of base oil; 15%-25% of a thickening agent; 1%-3% of an antioxidant; the thickening agent is prepared from isocyanate, organic amine and silicon dioxide.

Description

Technical Field

[0001] The present application belongs to the technical field of lubricating greases, and specifically relates to an extreme pressure-resistant and high temperature-resistant composite polyurea lubricating grease and a preparation method thereof. Background Art

[0002] Polyurea grease is a grease with good oxidation stability, thermal stability, mechanical stability and colloidal stability. It is suitable for lubrication occasions with high temperature, high load, wide speed range and contact with adverse media. It is widely used in various fields such as electrical appliances, metallurgy, automobiles, food, etc., and has broad development prospects.

[0003] However, some defects have been found in the use of polyurea grease, such as poor colloid stability, weak extreme pressure and anti-wear performance, and weak lubrication performance in high temperature environments. In response to these problems, scientific and technological workers have done a lot of research. Patent Publication No. CN118599586A discloses a high-temperature stability polyurea grease, which uses the method of ultra-high temperature induction polyurea thickener to improve the high temperature stability of polyurea grease, but the method is complicated and difficult to operate, and has certain production limitations. Patent Publication No. CN117586817A discloses a high-temperature resistant multi-component polyurea grease, which improves its high temperature resistance by using more than two monoamines, but it still has a lot of room for improvement in high temperature performance. Patent Publication No. CN102911772A discloses a composite barium-polyurea grease, which improves its extreme pressure and anti-wear performance and high temperature resistance by introducing carboxylic acid barium salt into polyurea molecules, but this method will increase the amount of thickener used and increase the cost of use. At the same time, the performance of the composite barium-based grease itself is not very stable, and the effect is not ideal.

[0004] Therefore, high temperature resistance and extreme pressure and anti-wear properties are the main issues to be solved in the current research and development of polyurea grease. Summary of the invention

[0005] In order to overcome the problems existing in the prior art, the present invention provides an extreme pressure resistant and high temperature resistant composite polyurea grease and a preparation method thereof, by introducing silicon dioxide into urea molecules to form a composite polyurea thickener, so that it has good extreme pressure performance and a longer bearing service life at high temperature.

[0006] The present invention provides an extreme pressure resistant and high temperature resistant composite polyurea grease, which comprises the following components by mass percentage: Base oil 65%-80%; thickener 15%-25%; antioxidant 1%-3%; the thickener is an isocyanate compound, prepared from organic amine and silicon dioxide.

[0007] Furthermore, the base oil is one of mineral lubricating oil and synthetic lubricating oil or a mixture of the two, such as 150BS, 500SN, ester oil, etc.

[0008] Furthermore, the isocyanate compound is diphenylmethane diisocyanate MDI.

[0009] Furthermore, the organic amine is one or more of octadecylamine, dodecylamine, cyclohexylamine or p-benzylamine.

[0010] Furthermore, the silicon dioxide is selected from 1000-3000 mesh silicon dioxide.

[0011] Furthermore, the organic amine is a combination of cyclohexylamine and octadecylamine.

[0012] Furthermore, the mass ratios of the components in the thickener are: MDI 5%-7%; cyclohexylamine 2%-3%; octadecylamine 3%-5%; and silicon oxide 5%-10%.

[0013] Furthermore, the antioxidant is one or more of diphenylamine, diisooctyl diphenylamine or ammonium sulfide formate.

[0014] The present invention also provides a method for preparing the above-mentioned extreme pressure resistant and high temperature resistant composite polyurea grease, comprising the following steps: (1) Mix 1 / 2 base oil and MDI, heat to 70-90°C, and keep the temperature constant for 30-60 minutes; (2) Mix 1 / 2 base oil and cyclohexylamine, heat to 70-90°C, keep constant temperature for 30-60 minutes, add octadecylamine, and stir evenly; (3) Combine step (1) and step (2), stir and heat to 80°C-100°C, and keep the temperature constant for 1-2 hours.

[0015] (4) At 90℃-100℃, add silicon dioxide and stir for 30-60 minutes; (5) Raise the temperature to 130°C-160°C and keep the temperature constant for 30-60 minutes; (6) Cool down to 80℃-100℃, add antioxidant, stir evenly, degas and extract fat. Beneficial Effects

[0016] The grease obtained in the present application is a composite polyurea grease. By introducing silicon dioxide into urea molecules, the grease not only has good extreme pressure and anti-wear properties, but also prolongs the service life of the bearing at high temperatures and saves production costs.

[0017] The molecular structure of silica-polyurea compounds includes aliphatic hydrocarbon groups, aromatic hydrocarbon groups and various polar groups. Inside the micelle, the polar groups in the molecules attract each other. The silica-polyurea molecules form a three-dimensional structural skeleton in the mineral oil. The oil is adsorbed in the gaps of these skeletons to form a stable colloidal structure.

[0018] A certain amount of antioxidant is added to the grease, which effectively solves the problem of its weak antioxidant ability at high temperatures.

[0019] Compared with other types of composite polyurea greases, the implementation scheme and steps of the present application are simpler and more effective, which is conducive to reducing costs. DETAILED DESCRIPTION

[0020] The present application is described in detail with reference to the embodiments, which are only further elaborations of the present application but are not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included within the scope of protection of the present invention. Unless otherwise specified in the following embodiments and comparative examples, the silicon dioxide used is 3000 mesh silicon dioxide.

[0021] An embodiment of the present invention: an extreme pressure resistant and high temperature resistant composite polyurea grease, comprising the following components by mass percentage: Base oil 65%-80%; thickener 15%-25%; antioxidant 1%-3%; the thickener is prepared from diphenylmethane diisocyanate, organic amine and silicon dioxide. The silicon dioxide is 1000-3000 silicon dioxide.

[0022] Furthermore, the base oil is a mineral lubricating oil or a synthetic lubricating oil, or a mixture of the two.

[0023] Further, the organic amine is one or more of octadecylamine, dodecylamine, cyclohexylamine or p-benzylamine. Preferably, the organic amine is a combination of cyclohexylamine and octadecylamine.

[0024] Furthermore, the mass ratios of the components in the thickener are: MDI 5%-7%; cyclohexylamine 2%-3%; octadecylamine 3%-5%; and silicon dioxide 5%-10%.

[0025] Furthermore, the antioxidant is one or more of diphenylamine, diisooctyl diphenylamine or ammonium sulfide formate.

[0026] Another embodiment of the present invention is a method for preparing the above-mentioned extreme pressure resistant and high temperature resistant composite polyurea grease, comprising the following steps: (1) Mix 1 / 2 base oil and MDI, heat to 70-90°C, and keep the temperature constant for 30-60 minutes; (2) Mix 1 / 2 base oil and cyclohexylamine, heat to 70-90°C, keep constant temperature for 30-60 minutes, add octadecylamine, and stir evenly; (3) Combine step (1) and step (2), stir and heat to 80°C-100°C, and keep the temperature constant for 1-2 hours; (4) At 90℃-100℃, add silicon dioxide and stir for 30-60 minutes; (5) Raise the temperature to 130°C-160°C and keep the temperature constant for 30-60 minutes; (6) Cool down to 80℃-100℃, add antioxidant, stir evenly, degas and extract fat.

[0027] Example 1 This embodiment provides a grease composition, comprising the following material components: Base oil: 400 grams (150BS is used as the base oil), MDI: 33 grams, cyclohexylamine: 12 grams, octadecylamine: 22 grams, silicon dioxide: 45 grams; antioxidant: 10 grams (diphenylamine is used as the antioxidant).

[0028] The preparation method is as follows: ① Mix 200g base oil and 33g MDI, heat to 80℃ and keep the temperature constant for 40 minutes; ② Mix 200g base oil and 12g cyclohexylamine, heat to 80℃, keep constant temperature for 40 minutes, add 22g octadecylamine, and stir evenly; ③ Combine step ① and step ②, stir and heat to 90℃, and keep the temperature constant for 1 hour; ④ Raise the temperature to 95°C, add 45g of silicon dioxide, and stir for 30 minutes; ⑤ Raise the temperature to 150℃ and keep it constant for 30 minutes; ⑥ Cool down to 80℃, add 10g diphenylamine, stir evenly, degas and extract fat.

[0029] Example 2 This embodiment provides a grease composition, comprising the following material components: Base oil: 400 grams (500SN is selected as the base oil), MDI: 33 grams, cyclohexylamine: 12 grams, octadecylamine: 22 grams, silica 45 grams, antioxidant: 10 grams (diphenylamine is selected as the antioxidant).

[0030] The preparation method is as follows: ① Mix 200g base oil and 33g MDI, heat to 80℃ and keep the temperature constant for 40 minutes; ② Mix 200g base oil and 12g cyclohexylamine, heat to 80℃, keep constant temperature for 40 minutes, add 22g octadecylamine, and stir evenly; ③ Combine step ① and step ②, stir and heat to 90℃, and keep the temperature constant for 1 hour; ④ Raise the temperature to 95°C and add 45g of silicon dioxide. Stir for 30 minutes; ⑤ Raise the temperature to 150℃ and keep it constant for 30 minutes; ⑥ Cool down to 80℃, add 10g diphenylamine, stir evenly, degas and extract fat.

[0031] Example (III) This embodiment provides a grease composition, comprising the following material components: Base oil: 400 g (the base oil is a mixture of 150BS and 500SN, the mass ratio of the two is 2:1), MDI: 33 g, cyclohexylamine: 12 g, octadecylamine: 22 g, silica 45 g, antioxidant: 10 g (the antioxidant is diphenylamine).

[0032] The preparation method is as follows: ① Mix 200g base oil and 33g MDI, heat to 80℃ and keep the temperature constant for 40 minutes; ② Mix 200g base oil and 12g cyclohexylamine, heat to 80℃, keep constant temperature for 40 minutes, add 22g octadecylamine, and stir evenly; ③ Combine step ① and step ②, stir and heat to 90℃, and keep the temperature constant for 1 hour; ④ Raise the temperature to 95°C, add 45g of silicon dioxide, and stir for 30 minutes; ⑤ Raise the temperature to 150℃ and keep it constant for 30 minutes; ⑥ Cool down to 80℃, add 10g diphenylamine, stir evenly, degas and extract fat.

[0033] Comparative Example (I) This comparative example provides a grease composition, comprising the following material components: Base oil: 400 grams (150BS is used as the base oil), MDI: 33 grams, cyclohexylamine: 12 grams, octadecylamine: 22 grams, antioxidant: 10 grams (diphenylamine is used as the antioxidant).

[0034] The preparation method is as follows: ① Mix 200g base oil and 33g MDI, heat to 80℃ and keep the temperature constant for 40 minutes; ② Mix 200g base oil and 12g cyclohexylamine, heat to 80℃, keep constant temperature for 40 minutes, add 22g octadecylamine, and stir evenly; ③ Combine step ① and step ②, stir and heat to 90℃, and keep the temperature constant for 1 hour; ④ Raise the temperature to 150℃ and keep it constant for 30 minutes; ⑤ Cool down to 80℃, add 10g diphenylamine, stir evenly, degas and extract fat.

[0035] Comparative Example (II) This comparative example provides a grease composition, comprising the following material components: Base oil: 400 grams (500SN is selected as the base oil), MDI: 33 grams, cyclohexylamine: 12 grams, octadecylamine: 22 grams, antioxidant: 10 grams (diphenylamine is selected as the antioxidant).

[0036] The preparation method is as follows: ① Mix 200g base oil and 33g MDI, heat to 80℃ and keep the temperature constant for 40 minutes; ② Mix 200g base oil and 12g cyclohexylamine, heat to 80℃, keep constant temperature for 40 minutes, add 22g octadecylamine, and stir evenly; ③ Combine step ① and step ②, stir and heat to 90℃, and keep the temperature constant for 1 hour; ④ Raise the temperature to 150℃ and keep it constant for 30 minutes; ⑤ Cool down to 80℃, add 10g diphenylamine, stir evenly, degas and extract fat.

[0037] Performance testing: The examples and comparative examples were tested, and the obtained indicators are shown in the following table:

[0038] Through the analysis of various indicators in the embodiments and comparative examples, it can be seen that the composite polyurea grease obtained in this scheme has improved high temperature resistance and extreme pressure and anti-wear properties compared with general polyurea grease.

Claims

1. An extreme pressure and high temperature resistant composite polyurea grease, characterized in that: Calculated by mass percentage, it contains the following components: Base oil 65%-80%; thickener 15%-25%; antioxidant 1%-3%; the thickener is an isocyanate compound, an organic amine and silicon dioxide.

2. The extreme pressure and high temperature resistant composite polyurea grease according to claim 1, characterized in that: The base oil is a mineral lubricating oil or a synthetic lubricating oil, or a mixture of the two.

3. The extreme pressure and high temperature resistant composite polyurea grease according to claim 2, characterized in that: The isocyanate compound is diphenylmethane diisocyanate MDI.

4. The extreme pressure and high temperature resistant composite polyurea grease according to claim 3, characterized in that: The organic amine is one or more of octadecylamine, dodecylamine, cyclohexylamine or p-benzylamine.

5. The extreme pressure and high temperature resistant composite polyurea grease according to claim 4, characterized in that: The silicon dioxide is selected from 1000-3000 mesh silicon dioxide.

6. The extreme pressure and high temperature resistant composite polyurea grease according to claim 4, characterized in that: The organic amine is a combination of cyclohexylamine and octadecylamine.

7. The extreme pressure and high temperature resistant composite polyurea grease according to claim 6, characterized in that: The mass ratios of the components in the thickener are: MDI 5%-7%; cyclohexylamine 2%-3%; octadecylamine 3%-5%; and silicon dioxide 5%-10%.

8. The extreme pressure and high temperature resistant composite polyurea grease according to claim 7, characterized in that: The antioxidant is one or more of diphenylamine, diisooctyl diphenylamine or ammonium sulfide formate.

9. The method for preparing an extreme pressure resistant and high temperature resistant composite polyurea grease according to any one of claims 7 or 8, characterized in that: The following steps are involved: (1) Mix 1 / 2 base oil and MDI, heat to 70-90°C, and keep the temperature constant for 30-60 minutes; (2) Mix 1 / 2 base oil and cyclohexylamine, heat to 70-90°C, keep constant temperature for 30-60 minutes, add octadecylamine, and stir evenly; (3) Combine step (1) and step (2), stir and heat to 80°C-100°C, and keep the temperature constant for 1-2 hours; (4) At 90℃-100℃, add silicon dioxide and stir for 30-60 minutes; (5) Raise the temperature to 130°C-160°C and keep the temperature constant for 30-60 minutes; (6) Cool down to 80℃-100℃, add antioxidant, stir evenly, degas and extract fat.

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