Special extreme pressure lubricating grease for sealed bearing and preparation method of special extreme pressure lubricating grease

Abstract

According to the special extreme pressure lubricating grease for the sealed bearing and the preparation method of the special extreme pressure lubricating grease, a mixture of composite lithium-based lubricating grease and composite sodium-based lubricating grease is adopted as a raw material, and then a dispersing aid, a damping agent, an adhesive and an anti-wear reagent at extreme pressure are added, so that the special extreme pressure lubricating grease for the sealed bearing is obtained, and the lubricating grease also has excellent mechanical stability, high temperature resistance and extreme pressure wear resistance. The special extreme pressure lubricating grease for the sealed bearing is prepared from the following raw materials in parts by weight: 50-70 parts of composite lithium-based lubricating grease; 20-40 parts by weight of composite sodium-based lubricating grease; 5-8 parts by weight of a dispersing aid; 2-3 parts by weight of a damping agent; 1-2 parts by weight of an adhesive; and 1-2 parts by weight of an anti-wear reagent at extreme pressure.

Description

Technical Field

[0001] The invention belongs to the technical field of lubricating grease, and in particular relates to an extreme pressure lubricating grease special for sealed bearings and a preparation method thereof. Background Art

[0002] Some modern inspection equipment is generally composed of radiation source, mechanical scanning system, detector system, computer system, etc. In order to ensure the rotation inspection of objects, bearings play a vital role. Sealed bearings should not only have a fast speed during operation, but also minimize the impact of noise.

[0003] Therefore, the grease used for the maintenance of sealed bearings has special performance requirements. It must not only be able to adapt to high-speed operation, but also have the function of reducing noise. Summary of the invention

[0004] In order to overcome the problems existing in the prior art, the present invention provides an extreme pressure grease specially used for sealed bearings, which adopts a mixture of composite lithium-based grease and composite sodium-based grease as raw material, and then adds a dispersant, a vibration dampening agent, an adhesive, and an extreme pressure anti-wear agent, thereby obtaining an extreme pressure grease specially used for sealed bearings with excellent low noise performance, adhesion performance, excellent mechanical stability, high temperature resistance, and extreme pressure and anti-wear performance.

[0005] Further, it is composed of the following raw materials in parts by weight: Complex lithium-based grease: 50~70 parts by weight Complex sodium-based grease: 20-40 parts by weight Dispersant: 5-8 parts by weight Vibration damper: 2~3 parts by weight Adhesive: 1~2 parts by weight Extreme pressure anti-wear agent: 1~2 parts by weight Complex sodium-based grease itself has excellent adhesion properties, and the addition of adhesives can further improve its adhesion properties.

[0006] Furthermore, in parts by weight, the proportion of the components contained in the composite lithium-based grease is: Base oil: 70%-85% Thickener: 15%-30% The proportion of the ingredients contained in the complex sodium-based grease is: Base oil: 60%-75% Thickener: 20%-35% The base oil is a mineral lubricating oil or a synthetic lubricating oil, or a mixture of the two.

[0007] Furthermore, the base oil is one or two of 150BS, 500SN or ester oil.

[0008] Furthermore, the thickener of the composite lithium-based grease is a product of the reaction of lithium hydroxide, a higher fatty acid and a low molecular weight acid; wherein the higher fatty acid is an acid with carbon atoms of C12-C25, and is one of stearic acid, dodecyl hydroxystearic acid or oleic acid, preferably dodecyl hydroxystearic acid; The low molecular weight acid is a C2-C10 acid, which is one of boric acid, azelaic acid, sebacic acid or benzoic acid, preferably boric acid; the lithium hydroxide needs to be prepared into a lithium hydroxide aqueous solution for use, and the ratio of lithium hydroxide to water is 1:3~8, preferably 1:6.

[0009] Furthermore, in parts by weight, the ratio of lithium hydroxide: higher fatty acid: low molecular weight acid is 1-3: 2-5: 0.5-2, preferably 3: 5: 2.

[0010] Furthermore, the thickener of the composite sodium-based grease is a product of the reaction of sodium hydroxide, a higher fatty acid and a low molecular weight acid; wherein the higher fatty acid is one or a mixture of dodecyl hydroxystearic acid, stearic acid or oleic acid, preferably stearic acid; The low molecular weight acid is a C2-C10 acid, which is one of boric acid, azelaic acid, sebacic acid, benzoic acid or glacial acetic acid, preferably benzoic acid; the sodium hydroxide needs to be added with water, and the ratio of sodium hydroxide to water is 1:5-10, preferably 1:8.

[0011] Furthermore, in parts by weight, sodium hydroxide: higher fatty acid: low molecular weight acid = 4-6:2-4:1-3, preferably 5:3:2.

[0012] Furthermore, the dispersant is one of polyol esters; the vibration damper is one of dipentaerythritol ester or trimethylolpropane ester; the adhesive is one of polyisobutylene, natural rubber or polymethacrylate or a mixture thereof; the extreme pressure anti-wear agent is one of sulfided isobutylene, borate or antimony dithiocarbamate or a mixture thereof.

[0013] The present invention also provides a method for preparing the above-mentioned extreme pressure grease for sealed bearings, which comprises three steps of preparing a composite lithium-based grease, preparing a composite sodium-based grease and mixing. The specific steps are as follows: (I) Preparation of composite lithium-based grease Add 1 / 3-2 / 3 base oil into the reactor, stir and heat to 60-80℃, add higher fatty acids and low molecular weight acids, stir evenly and heat to 85-95℃, slowly add the prepared lithium hydroxide aqueous solution and heat to 100℃-120℃, saponify at constant temperature for 1-2 hours, heat to 180-220℃, add the remaining base oil and cool to 80-120℃ for standby use; (II) Preparation of complex sodium-based grease Put 1 / 2-2 / 3 of the base oil into the saponification kettle, add higher fatty acids and low molecular weight acids, heat up to 80-90°C, slowly add the prepared sodium hydroxide aqueous solution and heat up to 95-110°C, react at a constant temperature for 1-2 hours, heat up to 180-200°C, add the remaining base oil, cool down to 80-120°C, and set aside; (III) Mixed Mix the two greases together, add dispersant, vibration dampener, adhesive, extreme pressure anti-wear agent, stir evenly, grind and extract the grease. Beneficial Effects

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) Good adhesion performance. Complex sodium-based grease itself has excellent adhesion performance, and the addition of adhesives can further improve its adhesion performance.

[0015] (2) It has outstanding extreme pressure and anti-wear properties, which can greatly reduce the wear on bearings. Its performance far exceeds that of similar products on the market.

[0016] (3) Excellent noise reduction performance. The composite lithium-based grease is a grease with excellent low noise performance. At the same time, the dispersant also improves the low noise performance to a certain extent. After testing, its vibration value and noise level are both at the highest level.

[0017] (4) Good mechanical stability. The dispersant can effectively improve the dispersion effect when grease is mixed, making the two greases evenly dispersed and the product structure more stable. DETAILED DESCRIPTION

[0018] The present invention is described in detail below in conjunction with embodiments.

[0019] An embodiment of the present invention: An extreme pressure grease specially used for sealed bearings, which adopts a mixture of composite lithium-based grease and composite sodium-based grease as raw material, and then adds a dispersant, a vibration dampening agent, an adhesive, and an extreme pressure anti-wear agent, thereby obtaining an extreme pressure grease specially used for sealed bearings with excellent low noise performance, adhesion performance, excellent mechanical stability, high temperature resistance, and extreme pressure and anti-wear performance.

[0020] Further, it is composed of the following raw materials in parts by weight: Complex lithium-based grease: 50~70 parts by weight Complex sodium-based grease: 20-40 parts by weight Dispersant: 5-8 parts by weight Vibration damper: 2~3 parts by weight Adhesive: 1~2 parts by weight Extreme pressure anti-wear agent: 1~2 parts by weight The dispersant is one of the polyol esters; the vibration damper is one of the dipentaerythritol ester or the trimethylolpropane ester; the adhesive is one of the polyisobutylene, natural rubber or polymethacrylate or a mixture thereof; the extreme pressure anti-wear agent is one of the sulfided isobutylene, borate or antimony dithiocarbamate or a mixture thereof.

[0021] Complex sodium-based grease itself has excellent adhesion properties, and the addition of adhesives can further improve its adhesion properties.

[0022] Furthermore, in parts by weight, the proportion of the components contained in the composite lithium-based grease is: Base oil: 70%-85% Thickener: 15%-30% The thickener of the composite lithium-based grease is a product of the reaction of lithium hydroxide, higher fatty acid and low molecular weight acid; in parts by weight, the lithium hydroxide: higher fatty acid: low molecular weight acid = 1-3: 2-5: 0.5-2, preferably 3: 5: 2.

[0023] Wherein, the higher fatty acid is an acid with carbon atoms of C12-C25, which is one of stearic acid, dodecyl hydroxystearic acid or oleic acid, preferably dodecyl hydroxystearic acid; The low molecular weight acid is a C2-C10 acid, which is one of boric acid, azelaic acid, sebacic acid or benzoic acid, preferably boric acid; the lithium hydroxide needs to be prepared into a lithium hydroxide aqueous solution for use, and the ratio of lithium hydroxide to water is 1:3~8, preferably 1:6.

[0024] The proportion of the ingredients contained in the complex sodium-based grease is: Base oil: 60%-75% Thickener: 20%-35% The thickener of the composite sodium-based grease is a product of a reaction of sodium hydroxide, a higher fatty acid and a low molecular weight acid; in parts by weight, the ratio of sodium hydroxide:higher fatty acid:low molecular weight acid is 4-6:2-4:1-3, preferably 5:3:2.

[0025] Wherein, the higher fatty acid is one or a mixture of dodecyl hydroxystearic acid, stearic acid or oleic acid, preferably stearic acid; The low molecular weight acid is a C2-C10 acid, which is one of boric acid, azelaic acid, sebacic acid, benzoic acid or glacial acetic acid, preferably benzoic acid; the sodium hydroxide needs to be added with water, and the ratio of sodium hydroxide to water is 1:5-10, preferably 1:8.

[0026] The base oil is one of mineral lubricating oil or synthetic lubricating oil or a mixture of the two, such as one or both of 150BS, 500SN or ester oil.

[0027] Another embodiment of the present invention is a method for preparing the above-mentioned extreme pressure grease for sealed bearings, comprising three steps of preparing a composite lithium-based grease, preparing a composite sodium-based grease and mixing. The specific steps are as follows: (I) Preparation of composite lithium-based grease Add 1 / 3-2 / 3 base oil into the reactor, stir and heat to 60-80℃, add higher fatty acids and low molecular weight acids, stir evenly and heat to 85-95℃, slowly add the prepared lithium hydroxide aqueous solution and heat to 100℃-120℃, saponify at constant temperature for 1-2 hours, heat to 180-220℃, add the remaining base oil and cool to 80-120℃ for standby use; (II) Preparation of complex sodium-based grease Put 1 / 2-2 / 3 of the base oil into the saponification kettle, add higher fatty acids and low molecular weight acids, heat up to 80-90°C, slowly add the prepared sodium hydroxide aqueous solution, heat up to 95-110°C, react at constant temperature for 1-2 hours, heat up to 180-200°C, add the remaining base oil, cool down to 80-120°C, and set aside; (III) Mixed Mix the two greases together, add dispersant, vibration dampener, adhesive, extreme pressure anti-wear agent, stir evenly, grind and extract the grease.

[0028] Example 1 The extreme pressure grease for sealed bearings described in this embodiment is composed of the following components: Lithium complex grease: 600 g Complex sodium-based grease: 300 g Polyol fat: 60 g Dipentaerythritol ester: 20 g Polyisobutylene: 10 g Sulfurized isobutylene: 10 g Among them, the composition of the composite lithium-based grease is: 150BS base oil: 450g Lithium hydroxide: 45 g Dodecyl hydroxystearic acid: 75 g Boric acid: 30 g The ingredients of complex sodium-based grease are: 150BS base oil: 200 g Sodium hydroxide: 50 g Stearic acid: 30 g Benzoic acid: 20 g In this embodiment, the steps for preparing an extreme pressure grease for sealed bearings are as follows: (I) Preparation of composite lithium-based grease: Add 280 g of base oil into a reactor, add 75 g of benzoic acid and 30 g of boric acid, stir and heat to 85 °C, add 45 g of lithium hydroxide (aqueous solution), heat to 105 °C, saponify for 1 hour, heat to 210 °C, add the remaining 170 g of base oil, cool to 100 °C and set aside.

[0029] (ii) Preparation of composite sodium-based grease: Add 120 g of base oil into a reactor, add 30 g of stearic acid and 20 g of benzoic acid, raise the temperature to 90 °C, add 50 g of sodium hydroxide (aqueous solution), raise the temperature to 110 °C, saponify for 1 hour, raise the temperature to 190 °C, add the remaining 80 g of base oil, cool to 100 °C, and set aside.

[0030] (III) Mixing: Mix the two prepared greases together, add polyol grease, dipentaerythritol ester, polyisobutylene and sulfided isobutylene at 80°C, stir evenly and grind out the grease.

[0031] Example 2 The extreme pressure grease for sealed bearings described in this embodiment is composed of the following components: Lithium complex grease: 600 g Complex sodium-based grease: 300 g Polyol fat: 60 g Dipentaerythritol ester: 20 g Polyisobutylene: 10 g Sulfurized isobutylene: 10 g Among them, the composition of the composite lithium-based grease is: 500SN base oil: 450 g Lithium hydroxide: 45 g Dodecyl hydroxystearic acid: 75 g Boric acid: 30 g The ingredients of complex sodium-based grease are: 500SN base oil: 200 g Sodium hydroxide: 50 g Stearic acid: 30 g Benzoic acid: 20 g In this embodiment, the steps for preparing an extreme pressure grease for sealed bearings are as follows: (I) Preparation of composite lithium-based grease: Add 280 g of base oil into a reactor, add 75 g of benzoic acid and 30 g of boric acid, stir and heat to 85 °C, add 45 g of lithium hydroxide (aqueous solution), heat to 105 °C, saponify for 1 hour, heat to 210 °C, add the remaining 170 g of base oil, cool to 100 °C, and set aside.

[0032] (ii) Preparation of composite sodium-based grease: Add 120 g of base oil into a reactor, add 30 g of stearic acid and 20 g of benzoic acid, raise the temperature to 90 °C, add 50 g of sodium hydroxide (aqueous solution), raise the temperature to 110 °C, saponify for 1 hour, raise the temperature to 190 °C, add the remaining 80 g of base oil, cool to 100 °C, and set aside.

[0033] (III) Mixing: Mix the two prepared greases together, add polyol grease, dipentaerythritol ester, polyisobutylene and sulfided isobutylene at 80°C, stir evenly and grind out the grease.

[0034] Example (III) The extreme pressure grease for sealed bearings described in this embodiment is composed of the following components: Lithium complex grease: 600 g Complex sodium-based grease: 300 g Polyol fat: 60 g Dipentaerythritol ester: 20 g Polyisobutylene: 10 g Sulfurized isobutylene: 10 g Among them, the composition of the composite lithium-based grease is: Ester oil: 450 g Lithium hydroxide: 45 g Dodecyl hydroxystearic acid: 75 g Boric acid: 30 g The ingredients of complex sodium-based grease are: Ester oil: 200 g Sodium hydroxide: 50 g Stearic acid: 30 g Benzoic acid: 20 g In this embodiment, the steps for preparing an extreme pressure grease for sealed bearings are as follows: (I) Preparation of composite lithium-based grease: Add 280 g of base oil into a reactor, add 75 g of benzoic acid and 30 g of boric acid, stir and heat to 85 °C, add 45 g of lithium hydroxide (aqueous solution), heat to 105 °C, saponify for 1 hour, heat to 210 °C, add the remaining 170 g of base oil, cool to 100 °C, and set aside.

[0035] (ii) Preparation of composite sodium-based grease: Add 120 g of base oil into a reactor, add 30 g of stearic acid and 20 g of benzoic acid, raise the temperature to 90 °C, add 50 g of sodium hydroxide (aqueous solution), raise the temperature to 110 °C, saponify for 1 hour, raise the temperature to 190 °C, add the remaining 80 g of base oil, cool to 100 °C, and set aside.

[0036] (III) Mixing: Mix the two prepared greases together, add polyol grease, dipentaerythritol ester, polyisobutylene and sulfided isobutylene at 80°C, stir evenly and grind out the grease.

[0037] Performance Testing Embodiment (I) - (III) After testing, the obtained indicators are shown in the following table:

[0038] From the measured data in the table, it can be seen that the special grease for sealed bearings obtained in this scheme has good effects in high temperature resistance, mechanical stability, extreme pressure and anti-wear, adhesion and noise reduction performance.

Claims

1. An extreme pressure grease for sealed bearings, characterized in that: A mixture of composite lithium-based grease and composite sodium-based grease is used as the raw material, and a dispersant, a vibration damper, an adhesive, and an extreme pressure anti-wear agent are added to obtain an extreme pressure grease specially used for sealed bearings, which has excellent low noise performance, adhesion performance, excellent mechanical stability, high temperature resistance, and extreme pressure anti-wear performance.

2. The extreme pressure grease for sealed bearings according to claim 1, characterized in that: It is composed of the following raw materials in parts by weight: Complex lithium-based grease: 50-70 parts by weight Complex sodium-based grease: 20-40 parts by weight Dispersant: 5-8 parts by weight Vibration damper: 2~3 parts by weight Adhesive: 1~2 parts by weight Extreme pressure and anti-wear agent: 1~2 parts by weight.

3. The extreme pressure grease for sealed bearings according to claim 2, characterized in that: In parts by weight, the proportion of the components contained in the composite lithium-based grease is: Base oil: 70%-85% Thickener: 15%-30% The proportion of the ingredients contained in the complex sodium-based grease is: Base oil: 60%-75% Thickener: 20%-35% The base oil is a mineral lubricating oil or a synthetic lubricating oil, or a mixture of the two.

4. The extreme pressure grease for sealed bearings according to claim 3, characterized in that: The base oil is one or two of 150BS, 500SN or ester oil.

5. The extreme pressure grease for sealed bearings according to claim 3, characterized in that: The thickener of the composite lithium-based grease is a product of the reaction of lithium hydroxide, higher fatty acids and low molecular weight acids; wherein the higher fatty acids are acids with carbon atoms of C12-C25, such as stearic acid, dodecyl stearic acid or oleic acid; the low molecular weight acids are acids with C2-C10, such as boric acid, azelaic acid, sebacic acid or benzoic acid; the lithium hydroxide needs to be prepared into a lithium hydroxide aqueous solution for use, and the ratio of lithium hydroxide to water is 1:3~8.

6. The extreme pressure grease for sealed bearings according to claim 5, characterized in that: In parts by weight, the lithium hydroxide: higher fatty acid: low molecular weight acid=1~3:2~5:0.5~2.

7. The extreme pressure grease for sealed bearings according to claim 3, characterized in that: The thickener of the composite sodium-based grease is a product of the reaction of sodium hydroxide, higher fatty acids and low molecular weight acids; wherein the higher fatty acids are one or a mixture of dodecyl hydroxystearic acid, stearic acid or oleic acid; the low molecular weight acid is a C2-C10 acid, which is one of boric acid, azelaic acid, sebacic acid, benzoic acid or glacial acetic acid; the sodium hydroxide needs to be added with water, and the ratio of sodium hydroxide to water is 1:5~10.

8. The extreme pressure grease for sealed bearings according to claim 7, characterized in that: In parts by weight, sodium hydroxide: higher fatty acid: low molecular weight acid = 4~6:2~4:1~3.

9. The extreme pressure grease for sealed bearings according to claim 2, characterized in that: The dispersant is one of the polyol esters; the vibration damper is one of the dipentaerythritol ester or the trimethylolpropane ester; the adhesive is one of the polyisobutylene, natural rubber or polymethacrylate or a mixture thereof; the extreme pressure anti-wear agent is one of the sulfided isobutylene, borate or antimony dithiocarbamate or a mixture thereof.

10. A method for preparing an extreme pressure grease for sealed bearings according to any one of claims 1 to 9, characterized in that: The method includes three steps, namely, preparation of composite lithium-based grease, preparation of composite sodium-based grease and mixing. The specific steps are as follows: (I) Preparation of composite lithium-based grease Add 1 / 3-2 / 3 base oil into the reactor, stir and heat to 60-80℃, add higher fatty acids and low molecular weight acids, stir evenly and heat to 85-95℃, slowly add the prepared lithium hydroxide aqueous solution and heat to 100℃-120℃, saponify at constant temperature for 1-2 hours, heat to 180-220℃, add the remaining base oil and cool to 80-120℃ for standby use; (II) Preparation of complex sodium-based grease Put 1 / 2-2 / 3 of the base oil into the saponification kettle, add higher fatty acids and low molecular weight acids, heat up to 80-90°C, slowly add the prepared sodium hydroxide aqueous solution and heat up to 95-110°C, react at a constant temperature for 1-2 hours, heat up to 180-200°C, add the remaining base oil, cool down to 80-120°C, and set aside; (III) Mixed Mix the two greases together, add dispersant, vibration dampener, adhesive, extreme pressure anti-wear agent, stir evenly, grind and extract the grease.

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