CN1272530A - Preparation method of high dropping point diurea grease lubricant - Google Patents

Abstract

A method for preparing high dropping point diurea grease, comprising the following steps: (1) reacting C ₈ -C ₂₄ fatty amines with excess diisocyanate in the presence of base oil; (2) dissolving unreacted diurea grease with water. The diisocyanate is neutralized, and the reaction is continued until the temperature is 130-200°C. The dropping point of the diurea grease prepared by this method reaches 260-330°C, and the grease can be used for the lubrication of high-speed motor bearings, continuous casting machine bearings in iron and steel plants, automobile hub bearings, constant velocity universal joints, and precision instruments and meters .

Description

Preparation method of high dropping point diurea grease

The invention relates to a preparation method of high dropping point diurea grease.

Urea-based lubricating grease does not contain metal ions in the thickener, and will not catalyze the oxidation of base oil during high-temperature use, so it has a long service life and has become one of the important varieties of lubricating grease development today. Among them, diurea lubricating grease is particularly valued because of its simple raw materials. Diurea grease can be divided into symmetrical diurea grease and asymmetric diurea grease according to the amine used. Because symmetrical diurea is difficult to make grease with a high dropping point, it is generally made into asymmetrical diurea grease. Such as: JP1139696 (Ping 1-139696) is to prepare high dropping point diurea grease by changing the structure of diisocyanate; The high dropping point grease of thickening agent; US 5158694 reacts with diisocyanate and water and amine to make polyurea grease, and the structural formula of thickening agent is one of following:

R ₃ NH-[-OC-NHR ₄ NH-OC-NHR ₅ NH-] _n -OC-NHR ₄ NH-OC-NHR ₃

R ₃ NH-OC-NHR ₅ NH-[-OC-NHR ₄ NH-OC-NHR ₅ NH-] _n -OC-NHR ₃

R ₃ NH-[-OC-NHR ₄ NH-OC-NHR ₅ NH-] _n -OC-NHR ₃

The dropping point of its product is between 230 and 260°C. To prepare a grease with a high dropping point, additives that increase the dropping point are added.

The object of the present invention is to provide a method for preparing high dropping point diurea grease, which is simple to operate and does not need to add additives.

The preparation method provided by the invention comprises the following steps: (1) reacting C ₈ -C ₂₄ aliphatic amines with excess diisocyanate in the presence of base oil; (2) neutralizing unreacted diisocyanate with water, and continuing the reaction to a temperature of 130-200°C.

Specifically, the preparation method provided by the invention can be carried out as follows:

(1) Add fatty amine and excess diisocyanate to the base oil, and react at 25-120°C, preferably 50-100°C, for 0-1 hour until the fatty amine is completely reacted. Wherein the diisocyanate is 105mol%-250mol% of the theoretical amount, preferably 105mol%-200mol%, and the amount of base oil is 70-95% of the total weight of the reactants, preferably 75-90%.

The step reaction formula is:

Wherein, R ₁ -NH ₂ is an aliphatic amine, and R ₁ is a C ₈ -C ₂₄ alkyl group, preferably a C ₁₀ -C ₁₈ alkyl group. For example, the fatty amine may be decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine, and the like. OCN-R ₂ -NCO is diisocyanate, R ₂ can be aryl or alkyl, preferably C ₆ -C ₃₀ , more preferably C ₆ -C ₁₅ aryl. For example, the diisocyanate may be toluene diisocyanate, 4,4'-diisocyanate diphenylmethane, or the like.

Said base oil is 100SN～500SN lubricating oil, can be mineral oil, also can be synthetic oil.

(2) At 70-100°C, add excess water to completely neutralize the unreacted diisocyanate, continue the reaction until the temperature rises to 130-200°C, preferably 150-180°C, keep the temperature constant for 0-3 hours, preferably 10min-60min, It can be cooled out of the kettle, and the required grease can be obtained after grinding. The amount of water used is not particularly limited, as long as it is in excess.

The step reaction formula is:

Wherein n is an integer of 2-6.

In the high dropping point diurea lubricating grease prepared by the method of the present invention, other additives such as antioxidant, extreme pressure agent and antiwear agent can also be added as required.

The preparation method of the high dropping point diurea grease provided by the present invention is in the process of preparing symmetrical aliphatic diurea grease (the knot formula is R ₁ -NH-OCNH-R ₂ -NH-OCNH-R ₁ ), Increased the reaction of diisocyanate and water to generate polyureidodiamine (the structural formula is NH ₂ -R ₂ -[-NH-CO-NH-R ₂ -] _n -NH ₂ ), polyureidodiamine and symmetrical The aliphatic diurea thickener works together to increase the dropping point of the diurea grease to 260-330°C, expanding the application range of the grease. The high dropping point diurea lubricating grease prepared by the invention can be used for the lubrication of high-speed motor bearings, continuous casting machine bearings in iron and steel plants, automobile hub bearings, constant velocity universal joints, and precision instruments and meters.

Below in conjunction with example the present invention will be further described.

Examples 1-6 are the preparation of high dropping point diurea grease provided by the present invention.

Example 1

Take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and put it into a fat-making kettle, and add 68g (0.252mol) of octadecylamine (product of Shandong China Resources Co., Ltd., industrial grade), stir and heat, when the temperature rises to 80°C, Speed up the stirring, and add 44g (0.252mol) of toluene diisocyanate (TDI-2,4, the product of Shanghai Reagent No. 1 Factory, chemically pure) at the same time. After the complete reaction of octadecylamine and TDI, the temperature rises to 100°C, and 2ml of water is added. After the water and TDI have completely reacted and evaporated, continue heating to 150°C, cool out of the kettle, and finally grind twice with a three-wheel mill. The product performance is shown in Table 1.

Example 2

Take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and put it into a fat-making kettle, add 68g (0.252mol) of octadecylamine, stir and heat, when the temperature rises to 80°C, speed up the stirring, and add TDI-2, 433g at the same time (0.189mol), when octadecylamine and TDI react completely, the temperature rises to 100°C, add 2ml of water, after the water and TDI completely react and evaporate, continue heating to 150°C, keep the temperature for 30 minutes, cool out of the kettle, and finally Grind twice with a three-wheel mill. The product performance is shown in Table 1.

Example 3

Take paraffin-based lubricating oil with a viscosity of 10cSt at 100°C as the base oil, add 61g (0.226mol) of octadecylamine into the fat-making kettle, then add 410g of base oil, stir and heat until the temperature rises to 80°C, and melt the octadecylamine Simultaneously in another container with 52.3g (0.209mol) 4,4'-diisocyanate diphenylmethane (MDI, Yantai Synthetic Leather Factory, trade mark MT-A) is melted in 100g base oil, then MDI is poured into In the grease kettle, the temperature rises to 100°C, add 2ml of water, after the water and MDI completely react and evaporate, continue heating, when the temperature rises to 160°C, cool out of the kettle, and finally grind twice with a three-wheel mill. The product performance is shown in Table 1.

Example 4

Take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and put it into a fat-making kettle, and add 61.24g (0.330mol) of dodecylamine (product of Shandong China Resources Co., Ltd., industrial grade), stir and heat, when the temperature rises to 50°C , speed up the stirring, and add 43.14g TDI-2,4 at the same time, when the dodecylamine and TDI react completely, the temperature rises to 80°C, then add 2ml of water, after the water and TDI completely react and evaporate, continue heating to 180°C When it is hot, cool it out of the kettle, and finally grind it twice with a three-wheel mill. The product performance is shown in Table 1.

Example 5

Take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and add it to the fat-making kettle, and add 53.75g (0.29mol) of dodecylamine, stir and heat, when the temperature rises to 60°C, speed up the stirring, and simultaneously add 54.14g of MDI ( 0.216mol), when dodecylamine and MDI completely react, the temperature rises to 100°C, then add 2ml of water, after the water and MDI completely react and evaporate, continue heating to 180°C, cool out of the kettle, and finally use three rounds of Grind Grind twice. The product performance is shown in Table 1.

Example 6

Take 410g of paraffin-based lubricating oil with a viscosity of 10cSt at 100°C and add it to the fat-making kettle, and add 50g (0.318mol) of decylamine (product of Beijing Xudongsheng Chemical Factory, chemically pure), stir and heat, when the temperature rises to 50°C, Add 42g (0.168mol) MDI dissolved in 100g of the same base oil, when decylamine and MDI react completely, the temperature rises to 100°C, add excess water 2ml, after water and MDI completely react and evaporate, continue heating to At 180°C, cool it out of the kettle, and finally grind it twice with a three-wheel mill. The product performance is shown in Table 1.

Comparative examples 1-3 are the preparation of ordinary symmetrical aliphatic diurea grease.

Comparative example 1

Compared with Example 1, take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and add it to the fat-making kettle, and add 68g (0.252mol) of octadecylamine, stir and heat, when the temperature rises to 80°C, speed up the stirring, and add 22g (0.126mol) of TDI-2,4, after the complete reaction of octadecylamine and TDI, the temperature rose to 100°C, continued heating to 150°C, cooled out of the kettle, and finally ground twice with a three-wheel mill. The product performance is shown in Table 2.

Comparative example 2

Compared with Example 4, take 510g of paraffin-based lubricating oil with a viscosity of 20cSt at 100°C and add it to the fat-making kettle, and add 61.24g (0.330mol) of dodecylamine, stir and heat, when the temperature rises to 50°C, speed up the stirring, and at the same time Add 28.75 g (0.165 mol) of TDI-2,4, continue heating to 180 ° C, cool out of the kettle, and finally grind twice with a three-wheel mill. The product performance is shown in Table 2.

Comparative example 3

Compared with Example 6, take 410g of paraffin-based lubricating oil with a viscosity of 10cSt at 100°C and add it to the fat-making kettle, and add 50g (0.318mol) of decylamine, stir and heat, and when the temperature rises to 50°C, add the same lubricating oil dissolved in 100g 39.78g (0.159mol) of MDI in the base oil, when decylamine and MDI react completely, the temperature rises to 100°C, and when the heating is continued to 180°C, it is cooled out of the kettle, and finally ground twice with a three-wheel mill. The product performance is shown in Table 2.

Table 1 Example 1 2 3 4 5 6 amine octadecylamine octadecylamine octadecylamine Dodecylamine Dodecylamine Decylamine Isocyanate TDI TDI MDI TDI MDI MDI Amount of isocyanate/theoretical amount 200% 150% 120% 150% 150% 105% Dropping point, ℃ 270 260 275 298 327 320 1/4 cone penetration, mm 80 52 52 89 63 70

Table 2 serial number Comparative example 1 Comparative example 2 Comparative example 3 amine octadecylamine Dodecylamine Decylamine Isocyanate TDI TDI MDI Dropping point, ℃ 180 205 160 1/4 cone penetration, mm ---- ---- ----

Claims (11)

1. A preparation method for high dropping point diurea grease, characterized in that it comprises the steps of: (1) in the presence of base oil, C ₈ ~ C ₂₄ fatty amines are reacted with excess diisocyanate; (2) Neutralize the unreacted diisocyanate with water, and continue the reaction until the temperature is 130-200°C. 2. according to the preparation method described in claim 1, it is characterized in that, diisocyanate is 105mol%～250mol% of theoretical amount, and base oil consumption is 70～95% of reactant gross weight. 3. according to the described preparation method of claim 1 or 2, it is characterized in that, diisocyanate is 105mol%～200mol% of theoretical amount, and base oil consumption is 75～90% of reactant gross weight. 4. The preparation method according to claim 1, characterized in that the reaction temperature in step (1) is 25-120°C. 5. The preparation method according to claim 1 or 4, characterized in that the reaction temperature in step (1) is 50-100°C. 6. The preparation method according to claim 1, characterized in that the step (2) is to carry out the neutralization reaction at 70-100°C. 7. The preparation method according to claim 1, characterized in that, after the diisocyanate is completely neutralized in step (2), the reaction is continued until the temperature rises to 150-180° C., and the temperature is kept constant for 0-3 hours. 8. The preparation method according to claim 1, characterized in that the fatty amine is a C ₁₀ -C ₁₈ alkyl amine. 9. The preparation method according to claim 1, characterized in that the structure of the diisocyanate is OCN-R ₂ -NCO, and R ₂ is a C ₆ -C ₃₀ aryl group. 10. The preparation method according to claim 9, characterized in that R ₂ is an aryl group of C ₆ -C ₁₅ . 11. according to the described preparation method of claim 1, it is characterized in that, said base oil is 100SN～500SN lubricating oil.