A high temperature resistant multi-component polyurea grease and preparation method thereof

Abstract

The present invention provides a high temperature resistant multi-component polyurea grease and a preparation method thereof, wherein the polyurea grease composition comprises a base oil, a thickener and an additive, wherein the thickener is a mixture of multiple urea-based thickeners obtained by reacting a monoamine, a diamine and a diisocyanate, wherein the monoamine comprises at least dodecylamine and octylamine. The multi-component polyurea grease of the present invention has excellent high temperature resistance, is suitable for use in high temperature working conditions, and effectively prolongs the service life of the grease; and the preparation method is simple, easy to operate, and has low raw material cost, and is suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating grease, and in particular to a high-temperature resistant multi-component polyurea lubricating grease and a preparation method thereof. Background Art

[0002] Driven by the growing development of modern industry, mechanical equipment is also facing more complex working conditions. Blast furnaces, coke ovens, continuous casting and other equipment in steel plants have put forward higher requirements on the performance of grease to face harsh working conditions such as high temperature, high pressure, high load, radiation, etc.

[0003] The thickener system of polyurea grease does not contain metal cations, which avoids catalytic oxidation effects on the base oil and its thickener system, and has excellent antioxidant properties; at the same time, there are intermolecular hydrogen bonds in polyurea grease, forming a hollow tube fiber structure at high temperatures, which has good high temperature resistance. Based on the above excellent oxidation stability and thermal stability, since the use of polyurea thickeners to prepare polyurea grease in the 1950s, polyurea grease has been widely used in high-temperature and high-load lubrication conditions such as aviation, metallurgy and automobiles, and is considered to be the grease with the most development potential in the future.

[0004] At present, most polyurea greases are diurea polyurea greases generated by the reaction of amine salts (fatty amines and alicyclic amines) with diisocyanates (MDI), as shown below:

[0005]

[0006] Later, tetraurea and pentaurea thickeners were prepared. For example, CN111394150A discloses a pentaurea grease, the raw materials of which include base oil, diisocyanate, organic monoamine, urea and inorganic lubricant. The high temperature resistance of the obtained pentaurea grease is significantly better than that of diurea polyurea grease. However, in view of the ever-increasing requirements, there is still room for further improvement in high temperature resistance and lubrication. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a high-temperature resistant multi-component polyurea grease and a preparation method thereof. The grease has good high-temperature resistance and good lubrication effect at high temperatures.

[0008] The invention provides a high temperature resistant multi-component polyurea grease composition, comprising a base oil, a thickener and an additive, wherein the thickener is a mixture of multiple urea-based thickeners obtained by reacting a monoamine, a diamine and a diisocyanate, wherein the monoamine comprises at least dodecylamine and octylamine.

[0009] In the prior art, in order to improve the high temperature resistance of polyurea grease, the commonly used measure is to modify it with a composite metal base. For example, CN109913295A uses a potassium base to modify tetraurea grease, and CN109971528A provides a composite sodium base tetraurea grease. However, the addition of a metal base will cause the high temperature oxidation stability of the grease to be weaker than that of pure polyurea grease.

[0010] The present invention has been found that, based on the tetraurea thickener prepared by the reaction of monoamine, diamine and diisocyanate, a multi-component polyurea thickener can be generated by using at least two monoamines, that is, the thickener is a mixture (the reaction formula is as follows, wherein the diamine is 4,4-methylenedianiline as an example), and the monoamine includes at least dodecylamine and octylamine. The obtained polyurea grease composition has better high temperature resistance, is suitable for use in high temperature working conditions, and effectively extends the service life of the grease.

[0011]

[0012] Among them, the theoretical reaction ratio of monoamine, diamine and diisocyanate is 2:1:2.

[0013] In some embodiments of the present invention, the diamine is one or more of ethylenediamine, phenylenediamine, and 4,4-methylenedianiline, preferably 4,4-methylenedianiline (MDA for short).

[0014] In some embodiments of the present invention, the diisocyanate is diphenylmethane-4,4'-diisocyanate (MDI for short).

[0015] In some embodiments of the present invention, the ratio of the total molar number of isocyanate groups in the diisocyanate to the total molar number of amino groups in the monoamine and diamine is 1-1.1: 1. To ensure complete reaction of the amine, the isocyanate may be slightly excessive.

[0016] In some embodiments of the present invention, in order to withstand high temperatures above 180° C., the additive includes an antioxidant, and the antioxidant is an amine antioxidant selected from one or more of diphenylamine, alkylated diphenylamine, naphthylamine and p-phenylenediamine.

[0017] In some embodiments of the present invention, the base oil is a lubricating oil, including one or more of mineral base oil, ester oil, polyalphaolefin (PAO), phenyl silicone oil, dimethyl silicone oil, ethyl silicone oil and other synthetic silicone oils.

[0018] Preferably, the kinematic viscosity of the base oil at 100°C is 15-35 mm 2 / s. Viscosity less than 15mm 2 / s, the high temperature adhesion of the product becomes worse, and the viscosity is greater than 35mm 2 / s The cost of the product is too high.

[0019] In some embodiments of the present invention, based on the total mass of the polyurea grease composition, the amount of the thickener is 10%-20%, the amount of the base oil is 75%-85%, and the amount of the additive is 1.5%-5%.

[0020] In some embodiments of the present invention, the additive comprises only an antioxidant.

[0021] On the other hand, the present invention also provides a method for preparing the above-mentioned high temperature resistant multi-component polyurea grease composition.

[0022] The preparation method provided by the present invention comprises: adding 40-70wt% of base oil and all amines into a reaction kettle, heating to 110-120°C, adding all diisocyanates dissolved in the remaining base oil, and reacting at a constant temperature of 110-120°C for 50-60min; after the reaction is completed, heating to 200-210°C, adding additives, stirring at a constant temperature, and cooling naturally after mixing.

[0023] Preferably, all the amines are added to the reactor in batches, with relatively inactive amines added first and relatively active amines added second.

[0024] In some embodiments of the present invention, when the monoamines are only dodecylamine and octylamine, dodecylamine is added first and then octylamine is added.

[0025] In a preferred embodiment of the present invention, the preparation method comprises the following steps:

[0026] (1) Weigh relatively inactive monoamine, diamine and part of base oil into a reaction kettle, heat to 110-120°C and stir to dissolve;

[0027] (2) Weigh a portion of the base oil and relatively active monoamine, heat and stir until the monoamine is evenly dispersed in the base oil, and add them into a reactor;

[0028] (3) Weighing part of the base oil and the entire mass of the diisocyanate, heating and stirring until the diisocyanate is evenly dispersed in the base oil, and adding them into a reaction kettle;

[0029] (4) the mixture in the reactor is kept at a constant temperature of 110-120° C. for 50-60 minutes;

[0030] (5) Raise the temperature to 200-210° C., add additives and stir at a constant temperature for 5-10 minutes, then turn off the heating, cool naturally to room temperature, take out the product, grind and disperse it to obtain a high-temperature resistant multi-component polyurea grease.

[0031] The present invention provides a high-temperature resistant multi-component polyurea grease and a preparation method thereof. A mixture of various urea-based thickeners is prepared by reacting specific monoamines and diamines as amine sources with diisocyanates, thereby obtaining a polyurea grease with excellent high-temperature resistance. The grease is suitable for use in high-temperature working conditions and effectively prolongs the service life of the grease. The preparation process is simple and suitable for industrial production. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] If no specific techniques or conditions are specified in the examples, the techniques or conditions described in the literature in the field or the product instructions are used. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0034] Example 1

[0035] This embodiment provides a high temperature resistant multi-component polyurea grease composition, which is composed of 1940 g of a mineral base oil (a mixture of paraffin-based mineral oil and cycloalkyl mineral oil in a mass ratio of 1:1), a thickener (obtained by reacting 89 g of dodecylamine, 42 g of n-octylamine, 65 g of MDA and 163 g of MDI) and 58 g of an antioxidant (diphenylamine).

[0036] The preparation method is as follows:

[0037] Add 940g of mineral base oil, 65g of MDA and 89g of dodecylamine to the reactor, mix and heat to 110-120°C, stir and disperse to dissolve; stir and disperse 42g of n-octylamine and 300g of mineral base oil to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 163g of MDI and 700g of mineral base oil to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120°C, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210°C, add 58g of diphenylamine and stir at a constant temperature for 5min; then cool to room temperature and grind to homogenize multi-component polyurea grease.

[0038] Example 2

[0039] This embodiment provides a high temperature resistant multi-component polyurea grease composition, which is composed of 1700g of mineral base oil (a mixture of paraffin-based mineral oil and cycloalkyl mineral oil in a mass ratio of 1.5:1), a thickener (obtained by reacting 70g of dodecylamine, 43g of n-octylamine, 52g of MDA and 135g of MDI) and 51g of an antioxidant (diphenylamine).

[0040] The preparation method is as follows:

[0041] Add 900g of mineral base oil, 52g of MDA and 70g of dodecylamine to the reactor, mix and heat to 110-120°C, stir and disperse to dissolve; stir and disperse 43g of n-octylamine and 250g of mineral base oil to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 135g of MDI and 550g of mineral base oil to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120°C, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210°C, add 51g of diphenylamine and keep the temperature constant for 5min; then cool to room temperature and grind to homogenize multi-component polyurea grease.

[0042] Example 3

[0043] This embodiment provides a high temperature resistant multi-component polyurea grease composition, which is composed of 2050 g of polyalphaolefin, a thickener (obtained by reacting 110 g of dodecylamine, 60 g of n-octylamine, 80 g of MDA and 200 g of MDI) and 64 g of an antioxidant (diphenylamine).

[0044] The preparation method is as follows:

[0045] Add 1000g polyalphaolefin, 80g MDA and 110g dodecylamine to the reactor, mix and heat to 110-120℃, stir and disperse to dissolve; stir and disperse 60g n-octylamine and 350g polyalphaolefin to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 200g MDI and 700g polyalphaolefin to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120℃, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210℃, add 64g diphenylamine and keep the temperature constant for 5min; then cool to room temperature and grind to homogenize multi-component polyurea grease.

[0046] Example 4

[0047] This embodiment provides a high temperature resistant multi-component polyurea grease composition, which is composed of 1914 g of dimethyl silicone oil, a thickener (obtained by reacting 68 g of dodecylamine, 39 g of n-octylamine, 51 g of MDA and 128 g of MDI) and 58 g of an antioxidant (diphenylamine).

[0048] The preparation method is as follows:

[0049] Add 914g dimethyl silicone oil, 51g MDA and 68g dodecylamine to the reactor, mix and heat to 110-120℃, stir and disperse to dissolve; stir and disperse 39g n-octylamine and 300g dimethyl silicone oil to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 128g MDI and 700g dimethyl silicone oil to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120℃, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210℃, add 58g diphenylamine and keep the temperature for 5min; then cool to room temperature, grind and homogenize to obtain polyurea grease.

[0050] Comparative Example 1

[0051] This comparative example provides a polyurea grease, and the preparation method is as follows:

[0052] Add 914g of mineral base oil and 83g of dodecylamine into the reactor, mix and heat to 110-120°C, stir and disperse to dissolve; stir and disperse 48g of n-octylamine and 300g of mineral base oil to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 155g of MDI and 700g of mineral base oil to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120°C, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210°C, add 58g of diphenylamine and keep the temperature constant for 5min; then cool to room temperature, grind and homogenize to obtain polyurea grease.

[0053] Comparative Example 2

[0054] This comparative example provides a polyurea grease, and the preparation method is as follows:

[0055] Add 914g of mineral base oil and 158g of dodecylamine into the reactor, mix and heat to 110-120°C, stir and disperse to dissolve; stir and disperse 128g of MDI and 700g of mineral base oil to dissolve, and pour into the reactor after MDI is completely melted; heat the mixture in the reactor to 110-120°C, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210°C, add 58g of diphenylamine and keep the temperature constant for 5min; then cool to room temperature, grind and homogenize to obtain polyurea grease.

[0056] Comparative Example 3

[0057] This comparative example provides a polyurea grease, and the preparation method is as follows:

[0058] Add 914g of mineral base oil and 76g of cyclohexylamine into a reactor, mix and heat to 110-120°C, stir and disperse to dissolve; stir and disperse 63g of n-octylamine and 300g of mineral base oil to dissolve, and pour into the reactor after the n-octylamine is completely melted; stir and disperse 147g of MDI and 700g of mineral base oil to dissolve, and pour into the reactor after the MDI is completely melted; heat the mixture in the reactor to 110-120°C, and react at a constant temperature for 50-60min; continue to heat to the highest refining temperature of 200-210°C, add 58g of diphenylamine and keep the temperature constant for 5min; then cool to room temperature, grind and homogenize to obtain polyurea grease.

[0059] Comparative Example 4

[0060] Pentaurea grease provided by CN111394150A.

[0061] According to the preparation method described in CN111394150A, this comparative example provides a pentaurea grease, and the preparation method is as follows:

[0062] Add 500g of mineral base oil and 113.6g of MDI to the reactor, heat to 70°C, stir, disperse and dissolve; stir, disperse and dissolve 13.6g of urea and 500g of mineral base oil, pour into the reactor after the urea is completely melted, and react at 110°C for 10min; stir, disperse and dissolve 122.8g of octadecylamine and 500g of mineral base oil, pour into the reactor after the octadecylamine is completely melted, and keep warm at 110°C for 10min; add 166.7g of molybdenum disulfide and 83.3g of calcium fluoride to the reactor, heat to 200°C, and keep warm for 30min. Then cool to room temperature, grind and homogenize to obtain pentaurea grease.

[0063] The basic performance of the polyurea-based greases obtained in the examples and comparative examples was evaluated, and the results are shown in Table 1.

[0064] Table 1

[0065]

[0066] Among them, the high temperature cone penetration test method is as follows:

[0067] A.1 Scope

[0068] This method is suitable for evaluating the high temperature performance of grease.

[0069] A.2 Method Overview

[0070] This method is formulated with reference to GB / T 269. The sample is placed in a standard grease cup, placed in an oven at a specified test temperature (100°C, 180°C, etc.), kept at a constant temperature for a specified time (3h, 24h, etc.), and then taken out to measure its non-working cone penetration, so as to examine the high temperature performance of the grease sample.

[0071] A.3 Instruments

[0072] A.3.1 Cone penetrometer: in accordance with the requirements of GB / T 269.

[0073] A.3.2 Constant temperature box: The temperature can be controlled to ±1℃.

[0074] A.3.4 Thermometer: 0℃~250℃, graduation value is 1℃, and calibrated within the validity period.

[0075] A.3.5 Scraper.

[0076] A.3.6 Porcelain plate.

[0077] A.4 Test steps

[0078] A.4.1 Adjust the thermostat to the required test temperature.

[0079] A.4.2 Take a sufficient amount of sample and transfer it into two clean standard grease cups respectively. Press it tightly with a scraper to avoid mixing air. Scrape the surface of the sample with a scraper to remove excess grease sample.

[0080] A.4.3 Place the above-mentioned fat cup filled with the sample in a porcelain plate and put it in a constant temperature box adjusted to the test temperature for a specified time.

[0081] A.4.4 After the specified time has elapsed, take out the grease cup from the constant temperature box and immediately place it on the platform of the cone penetration meter. Measure the non-working cone penetration as described in 6.3-6.3.4 of Part I of GB / T 269. Try to measure the cone penetration at a constant temperature.

[0082] A.5 Result presentation

[0083] The arithmetic mean of the non-working cone penetration of two parallel samples is taken as the measurement result.

[0084] The above results show that the multi-component polyurea-based grease of the present invention is a high-temperature resistant, high-dropping-point grease with excellent high-temperature resistance, and the dropping point exceeds 300°C; even under high-temperature radiation, the difference between the high-temperature cone penetration at 180°C and the working cone penetration at room temperature is small, no oil dripping phenomenon is observed, and it still has good adhesion. The difference in this item of the three comparative samples is large, indicating that the polyurea-based grease composition of the present invention has a smaller consistency softening at high temperature, is not easy to lose, and has more excellent high-temperature resistance.

[0085] In summary, the multi-component polyurea-based grease of the present invention has better high temperature resistance than the existing polyurea-based grease, has a high dropping point, and its consistency softens less at high temperatures, is less likely to lose, and meets the lubrication requirements of the steel industry under harsh high temperature conditions.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high temperature resistant multi-component polyurea grease composition, It is characterized in that The invention is composed of a base oil, a thickener and an additive, wherein the thickener is a mixture of various urea-based thickeners obtained by reacting a monoamine, a diamine and a diisocyanate, wherein the monoamine includes at least dodecylamine and octylamine; the kinematic viscosity of the base oil at 100°C is 15-35 mm 2 / s; based on the total mass of the polyurea grease composition, the amount of the thickener is 10%-20%, the amount of the base oil is 75%-85%, and the amount of the additive is 1.5%-5%; the theoretical reaction ratio of the monoamine, the diamine and the diisocyanate is 2:1:2; the ratio of the total molar number of isocyanate groups in the diisocyanate to the total molar number of amino groups in the monoamine and the diamine is 1-1.1:1; The diamine is 4,4-methylenedianiline; The diisocyanate is diphenylmethane-4,4'-diisocyanate.

2. The high temperature resistant multi-component polyurea grease composition according to claim 1, It is characterized in that The additive comprises an antioxidant, and the antioxidant is selected from one or more of diphenylamine, alkylated diphenylamine, naphthylamine and p-phenylenediamine.

3. The high temperature resistant multi-component polyurea grease composition according to claim 1 or 2, It is characterized in that The base oil includes one or more of mineral base oil, ester oil, polyalphaolefin, phenyl silicone oil, dimethyl silicone oil, ethyl silicone oil and other synthetic silicone oils.

4. A method for preparing the high temperature resistant multi-component polyurea grease composition according to any one of claims 1 to 3, It is characterized in that include: Add 40-70wt% of base oil and all amines into the reactor, heat it to 110-120℃, add all diisocyanates dissolved in the remaining base oil, and react at 110-120℃ for 50-60min. After the reaction is completed, heat it to 200-210℃, add additives and stir at constant temperature, mix well and cool naturally.

5. The method for preparing the high temperature resistant multi-component polyurea grease composition according to claim 4, It is characterized in that All amines are added to the reactor in batches, with relatively inactive amines added first, followed by relatively active amines.

6. The method for preparing the high temperature resistant multi-component polyurea grease composition according to claim 5, It is characterized in that The preparation method comprises the following steps: (1) Weigh relatively inactive monoamine, diamine and part of base oil into a reactor, heat to 110-120°C and stir to dissolve; (2) Weigh a portion of the base oil and relatively active monoamine, heat and stir until the monoamine is evenly dispersed in the base oil, and add them into the reactor; (3) Weigh part of the base oil and the entire mass of diisocyanate, heat and stir until the diisocyanate is evenly dispersed in the base oil, and add them into the reactor; (4) The mixture in the reactor is kept at a constant temperature of 110-120°C for 50-60 minutes; (5) Raise the temperature to 200-210°C, add additives and stir at a constant temperature for 5-10 minutes, then turn off the heating, cool naturally to room temperature, take out the product, grind and disperse it to obtain a high-temperature resistant multi-component polyurea grease.

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