Flame-retardant lubricating grease and method for producing the same

Abstract

The application discloses a kind of fire-retardant type lubricating grease and preparation method thereof, belong to lubricating grease technical field, including the following steps: S1, base oil and diphenyl methane diisocyanate are placed in reaction kettle, 45-50 ℃ is stirred for 5-10 min, mixture a is added, 110 ℃ is stirred for 35-40 min, then mixture b is added, heat preservation stirring reaction 10-15 min, to obtain base ester;S2, deionized water, fire-retardant component, graphite and calcium fluoride are added to base ester, 210 ℃ is refined for 2h, cooling, anti-rust agent is added, homogenization treatment, degassing, to obtain fire-retardant type lubricating grease, the application utilizes urea and the chain extension reaction of diphenyl methane diisocyanate in base ester form rich urea group, improve the drop point of lubricating grease, introduce fire-retardant component to improve the fire-retardant performance and antioxidant property of lubricating grease, the obtained lubricating grease not only has higher drop point, also has good fire-retardant performance and antioxidant property.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lubricating grease, and particularly relates to a fire-retardant lubricating grease and a preparation method thereof. BACKGROUND

[0002] The polyurea-based lubricating grease is prepared from polyurea-based organic compounds, thickened minerals, synthetic oils and plant oils, and a small amount of additives, and has good pumpability, mechanical stability, colloidal stability and water resistance, and is particularly suitable for high-temperature and high-load lubrication occasions with a wide temperature range. In actual process application, different ways are used to improve the physical properties of the lubricating grease to meet the use requirements in the face of various harsh lubrication working environments.

[0003] At present, the dropping point of the polyurea-based lubricating grease is low, the use temperature is low, and the grease is easily lost during work. In a high-temperature environment, smoke is easily produced, and even fire occurs. In view of the above problems, Chinese patent CN109943402B discloses a synthetic low-carbon ultrahigh-temperature lubricating grease and a preparation method, which comprises trimellitate, polyisobutylene, polyurea and a functional additive. The functional additive comprises a high-temperature antioxidant, a copper corrosion-resistant additive, a black metal rust-proof and corrosion-proof agent, a fire-retardant lubricant, a fire-retardant smoke-suppressing agent and an ultrahigh-temperature solid lubricant. The fire-retardant lubricant is MCA, and the fire-retardant smoke-suppressing agent is nano-magnesium hydroxide. The MCA is easy to absorb moisture, has poor dispersibility in the lubricating grease, and is easy to form a lump. In the lubricating grease processing process, the MCA lump is easy to sublimate and lose due to heat, and cannot play a good fire-retardant role. Moreover, there is a large polarity difference between the nano-magnesium hydroxide and the lubricating grease, and the dispersibility is poor. It is difficult to obtain a fire-retardant lubricating grease with good performance. SUMMARY

[0004] The purpose of the present application is to provide a fire-retardant lubricating grease and a preparation method thereof, which solve the problems of low dropping point and poor fire-retardant property of the existing fire-retardant lubricating grease.

[0005] The purpose of the present application can be achieved by the following technical solutions.

[0006] A preparation method of a fire-retardant lubricating grease comprises the following steps:

[0007] S1, the base oil and diphenyl methane diisocyanate are placed in a reaction kettle, heated to 45-50 DEG C, stirred for 5-10 min, a mixture a composed of base oil and urea is added, heated to 110 DEG C, and stirred for 35-40 min. Then, a mixture b composed of base oil and octadecylamine is added, and the stirring reaction is kept for 10-15 min to obtain a base ester;

[0008] S2, adding deionized water, a flame-retardant component, graphite and calcium fluoride to the base ester obtained in S1, heating to 210 DEG C and refining for 2 hours, then cooling to room temperature, adding a rust inhibitor, homogenizing using a high-pressure homogenizer at a pressure of 20-30 MPa, and then degassing to obtain the flame-retardant lubricating grease.

[0009] The application uses base oil, diphenyl methane diisocyanate, urea, octadecylamine, a flame-retardant component, graphite and calcium fluoride as raw materials to prepare a flame-retardant lubricating grease. The chain extension reaction of urea and diphenyl methane diisocyanate forms abundant urea groups in the base ester. The increase of the urea group content causes the hydrogen bond between the oxygen atom of the carbonyl group in the polyurea molecule and the hydrogen atom in the amino group, which produces a fibrous network structure in space, improves the dropping point of the lubricating grease, and the introduced flame-retardant component has good flame-retardant performance and oxidation resistance, and the calcium fluoride has a similar layered structure with graphite and has strong metal combination ability, easily forms a dense lubricating layer on the surface of steel at high temperature, and has good lubricating capacity. Therefore, the prepared lubricating grease not only has a high dropping point, but also has good flame-retardant performance and oxidation resistance.

[0010] As a further technical scheme of the application, the mass ratio of the base oil, diphenyl methane diisocyanate, mixture a, mixture b, deionized water, a flame-retardant component, graphite, calcium fluoride and a rust inhibitor is 29.5:9.5:30.6:39.8:0.2-0.4:7-10:7:7:0.1-0.5.

[0011] As a further technical scheme of the application, mixture a is prepared by the following steps:

[0012] The base oil and urea are added to a reaction kettle in a mass ratio of 29.5:1.1, and stirred and mixed at a temperature of 135-140 DEG C for 20-30 min.

[0013] As a further technical scheme of the application, mixture b is prepared by the following steps:

[0014] The base oil and octadecylamine are added to a reaction kettle in a mass ratio of 29.5:10.3, and stirred for 10-20 min at a temperature of 55-60 DEG C.

[0015] As a further technical scheme of the application, the flame-retardant component is prepared by the following steps:

[0016] The DOPO-based monomer, alkali lignin, potassium carbonate and DMF are added to a three-necked flask, heated to 80 DEG C and stirred for 10-20 min, 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane is added and constant temperature reaction is carried out for 48 h, after the reaction is completed, the mixture is centrifuged, the precipitate is washed with anhydrous ethanol for several times, and finally dried in a vacuum drying oven at 80 DEG C for 12 h to obtain the flame-retardant component.

[0017] Lignin is a natural polymer material, which contains a large number of phenolic hydroxyl functional groups and large conjugated aromatic structure, high carbon content, excellent thermal stability at high temperature, can improve the antioxidant performance of the grease, and lignin contains a large number of benzene rings, which has a layered structure similar to graphite, and the high-density electron cloud of the benzene ring structure can form a coordination bond with the d empty orbit of Fe, Cu, Al and other non-ferrous metals, thereby forming a protective film to improve the friction reduction and wear resistance of the grease, but it has a high molecular weight and polarity, and is easy to agglomerate, and has poor dispersibility in polyurea grease, in view of this problem, the application uses DOPO-based monomer and 1,3-bis(chloromethyl)-1,1,3,3-tetramethyl disiloxane as raw materials to modify the surface of alkali lignin, and grafts hyperbranched polysiloxane on the surface of lignin through chemical bonds, based on the characteristics of low viscosity and high compatibility of hyperbranched polymers and the high compatibility between siloxane and base oil, the dispersibility of lignin in the grease is improved, in addition, the DOPO structure is introduced on the surface of lignin, which has good flame retardant effect, combined with the good carbonization effect of lignin itself, the excellent flame retardant property of the grease is improved, and the antioxidant property is improved.

[0018] As a further technical solution of the application, the amount ratio of DOPO-based monomer, alkali lignin, potassium carbonate, DMF and 1,3-bis(chloromethyl)-1,1,3,3-tetramethyl disiloxane is 7.4-8.0g:3.2-4.0g:6.5g:100-200mL:4.6-5.2g, the alkali lignin is used as the material to be modified, the 1,3-bis(chloromethyl)-1,1,3,3-tetramethyl disiloxane and the DOPO-based monomer are used as the reaction monomers, and the reaction of the hydroxyl groups on the alkali lignin structure and the hydroxyl groups of the DOPO-based monomer and the chlorine atoms of the 1,3-bis(chloromethyl)-1,1,3,3-tetramethyl disiloxane is carried out to remove HCl, so as to obtain the flame-retardant component.

[0019] As a further technical solution of the application, the DOPO-based monomer is prepared by the following steps:

[0020] DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-), 2,3,4-trihydroxybenzaldehyde and ethylene glycol methyl ether are added to a three-necked flask, nitrogen is introduced for protection, first heated to 90 DEG C and kept for 30 min, then heated to 140 DEG C and stirred for 4-6 h, after the reaction is completed, the solid crude product is obtained by vacuum filtration, washed with a mixed solvent of ethyl acetate and petroleum ether in a mass ratio of 1:1, and finally dried in a vacuum drying oven at 80 DEG C for 12 h to obtain the DOPO monomer;

[0021] In the above reaction, the molar ratio of DOPO and 2,3,4-trihydroxybenzaldehyde is 1:1, and the DOPO-based monomer containing one alcohol hydroxyl group, three phenolic hydroxyl groups and DOPO structure is obtained through the addition reaction between DOPO and 2,3,4-trihydroxybenzaldehyde.

[0022] As a further technical solution of the present application, the base oil is dimethyl silicone oil.

[0023] As a further technical solution of the present application, the rust inhibitor is at least one of lanolin, lanolin calcium soap, lanolin magnesium soap, barium petroleum sulfonate, barium dinonylnaphthalene sulfonate and alkenyl succinic acid.

[0024] As a further technical solution of the present application, the flame-retardant grease is prepared by the above preparation method.

[0025] The beneficial effects of the present application are:

[0026] 1. The present application uses base oil, diphenyl methane diisocyanate, urea, octadecylamine, flame-retardant component, graphite and calcium fluoride as raw materials to prepare a flame-retardant grease, uses the chain extension reaction of urea and diphenyl methane diisocyanate to form rich urea groups in the base ester, improves the dropping point of the grease, introduces the flame-retardant component to improve the flame-retardant performance and oxidation resistance of the grease, and introduces calcium fluoride and graphite to improve the lubricating capacity of the grease, so that the grease prepared by the present application not only has a high dropping point, but also has good flame-retardant performance and oxidation resistance.

[0027] 2. The present application uses DOPO-based monomer and 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane as raw materials to modify the surface of alkali lignin, and grafts hyperbranched polysiloxane on the surface of the lignin through chemical bonds, based on the characteristics of low viscosity and high compatibility of hyperbranched polymers and the high compatibility between siloxane and base oil, improves the dispersibility of lignin in the grease, and introduces DOPO structure on the surface of the lignin, combines the good flame-retardant carbonization effect and oxidation resistance of the lignin itself, and gives the grease excellent flame-retardant performance while improving its oxidation resistance. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Embodiment 1

[0030] The present embodiment provides a flame-retardant component, which is prepared by the following steps:

[0031] Into a three-necked flask were added 7.4 g of the DOPO-based monomer, 3.2 g of alkali lignin, 6.5 g of potassium carbonate and 100 mL of DMF, and the mixture was stirred at 80°C for 10 min, 4.6 g of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane was added, and the reaction was carried out at constant temperature for 48 h. After the reaction was completed, the mixture was centrifuged, the precipitate was washed with anhydrous ethanol for several times, and finally dried in a vacuum drying oven at 80°C for 12 h to obtain the flame-retardant component.

[0032] The DOPO-based monomer was prepared by the following steps:

[0033] Into a three-necked flask were added 0.1 mol of DOPO, 0.1 mol of 2,3,4-trihydroxybenzaldehyde and 500 mL of ethylene glycol methyl ether, and the mixture was protected by nitrogen, heated to 90°C for 30 min, and then stirred at 140°C for 4 h. After the reaction was completed, the solid crude product was obtained by vacuum filtration, washed with a mixed solvent of ethyl acetate and petroleum ether in a mass ratio of 1:1, and finally dried in a vacuum drying oven at 80°C for 12 h to obtain the DOPO monomer.

[0034] Example 2

[0035] This example provides a flame-retardant component, which was prepared by the following steps:

[0036] Into a three-necked flask were added 8.0 g of the DOPO-based monomer, 4.0 g of alkali lignin, 6.5 g of potassium carbonate and 200 mL of DMF, and the mixture was stirred at 80°C for 20 min, 5.2 g of 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane was added, and the reaction was carried out at constant temperature for 48 h. After the reaction was completed, the mixture was centrifuged, the precipitate was washed with anhydrous ethanol for several times, and finally dried in a vacuum drying oven at 80°C for 12 h to obtain the flame-retardant component.

[0037] The DOPO-based monomer was prepared by the following steps:

[0038] Into a three-necked flask were added 0.1 mol of DOPO, 0.1 mol of 2,3,4-trihydroxybenzaldehyde and 500 mL of ethylene glycol methyl ether, and the mixture was protected by nitrogen, heated to 90°C for 30 min, and then stirred at 140°C for 6 h. After the reaction was completed, the solid crude product was obtained by vacuum filtration, washed with a mixed solvent of ethyl acetate and petroleum ether in a mass ratio of 1:1, and finally dried in a vacuum drying oven at 80°C for 12 h to obtain the DOPO monomer.

[0039] Comparative Example 1

[0040] Comparative Example 1

[0041] Comparative Example 2

[0042] The present comparative example provides a kind of alkali lignin, is purchased from Tianjin Xienen Aoptec Technology Co., Ltd.

[0043] Example 3

[0044] A preparation method of a fire-retardant type lubricating grease, comprising the following steps:

[0045] S1, 29.5 kg of base oil and 9.5 kg of diphenyl methane diisocyanate are placed in a reaction kettle, heated to 45 DEG C, stirred for 5 min, 30.6 kg of mixture a is added, heated to 110 DEG C, stirred for 35 min, then 39.8 kg of mixture b is added, and stirred for 10 min to obtain a base ester;

[0046] S2, 0.2 kg of deionized water, 7 kg of the fire-retardant component of Example 1, 7 kg of graphite and 7 kg of calcium fluoride are added to the base ester obtained in S1, heated to 210 DEG C and refined for 2 h, then cooled to room temperature, 0.1 kg of a rust inhibitor is added, and a high-pressure homogenizer is used for homogenization treatment under a pressure of 20 MPa, and then degassed to obtain a fire-retardant type lubricating grease.

[0047] Wherein, mixture a is prepared by the following steps:

[0048] The base oil and urea are added to the reaction kettle in a mass ratio of 29.5:1.1, and stirred and mixed at a temperature of 135 DEG C for 30 min.

[0049] Mixture b is prepared by the following steps:

[0050] The base oil and octadecylamine are added to the reaction kettle in a mass ratio of 29.5:10.3, and stirred for 10 min at a temperature of 55 DEG C.

[0051] The base oil is dimethyl silicone oil, and the rust inhibitor is lanolin.

[0052] Example 4

[0053] A preparation method of a fire-retardant type lubricating grease, comprising the following steps:

[0054] S1, 29.5 kg of base oil and 9.5 kg of diphenyl methane diisocyanate are placed in a reaction kettle, heated to 45 DEG C, stirred for 5 min, 30.6 kg of mixture a is added, heated to 110 DEG C, stirred for 35 min, then 39.8 kg of mixture b is added, and stirred for 10 min to obtain a base ester;

[0055] S2, 0.3 kg of deionized water, 9 kg of the flame-retardant component of Example 2, 7 kg of graphite and 7 kg of calcium fluoride are added to the base ester obtained in S1, and the temperature is raised to 210 DEG C for refining for 2 h, and then cooled to room temperature, 0.3 kg of the rust preventive is added, and homogenized by using a high-pressure homogenizer under a pressure of 25 MPa, and then degassed to obtain the flame-retardant grease.

[0056] The mixture a is prepared by the following steps:

[0057] The base oil and urea are added into the reaction kettle in a mass ratio of 29.5:1.1, and stirred and mixed at a temperature of 138 DEG C for 25 min.

[0058] The mixture b is prepared by the following steps:

[0059] The base oil and octadecylamine are added into the reaction kettle in a mass ratio of 29.5:10.3, and stirred for 15 min at a temperature of 58 DEG C.

[0060] The base oil is dimethyl silicone oil, and the rust preventive is calcium lanolate.

[0061] Example 5

[0062] A preparation method of a flame-retardant grease comprises the following steps:

[0063] S1, 29.5 kg of base oil and 9.5 kg of diphenyl methane diisocyanate are placed into a reaction kettle, the temperature is raised to 50 DEG C, and stirred for 10 min, 30.6 kg of mixture a is added, the temperature is raised to 110 DEG C, and stirred and reacted for 40 min, then 39.8 kg of mixture b is added, and stirred and reacted for 15 min, to obtain a base ester;

[0064] S2, 0.4 kg of deionized water, 10 kg of the flame-retardant component of Example 2, 7 kg of graphite and 7 kg of calcium fluoride are added to the base ester obtained in S1, and the temperature is raised to 210 DEG C for refining for 2 h, and then cooled to room temperature, 0.5 kg of the rust preventive is added, and homogenized by using a high-pressure homogenizer under a pressure of 30 MPa, and then degassed to obtain the flame-retardant grease.

[0065] The mixture a is prepared by the following steps:

[0066] The base oil and urea are added into the reaction kettle in a mass ratio of 29.5:1.1, and stirred and mixed at a temperature of 140 DEG C for 30 min.

[0067] The mixture b is prepared by the following steps:

[0068] The base oil and octadecylamine are added into the reaction kettle in a mass ratio of 29.5:10.3, and stirred for 10 min at a temperature of 60 DEG C.

[0069] The base oil is dimethyl silicone oil, and the rust inhibitor is lanolin magnesium soap.

[0070] Comparative Example 3

[0071] Comparative Example 3, the flame-retardant component in Example 3 is replaced by the substance in Comparative Example 1, and the remaining raw materials and preparation process are the same as those in Example 3.

[0072] Comparative Example 4

[0073] Comparative Example 3, the flame-retardant component in Example 3 is replaced by the substance in Comparative Example 2, and the remaining raw materials and preparation process are the same as those in Example 3.

[0074] The lubricating greases obtained in Example 3-Example 5 and Comparative Example 3-Comparative Example 4 are tested, and the test items are as follows:

[0075] The drop point is determined according to the standard GB / T 3498-2008 "Determination of Drop Point of Lubricating Grease in Wide Temperature Range".

[0076] The flame-retardant performance is tested according to the standard ASTM D3801, and the operation is as follows: equal amounts of each group of lubricating greases are placed on an iron alloy plate at a temperature of 600 to 650℃, and whether the lubricating grease burns is observed;

[0077] The differential scanning calorimeter DSC 204HP produced by Germany NETZSCH Company is used to evaluate the oxidation resistance of each lubricating grease, and the test method is as follows: according to the method of ASTM D6186-08(2013), about 3.0mg sample is placed in an open aluminum pan and oxidized under a static oxygen pressure of 3.5±0.2MPa, the heating rate is increased from room temperature to 350℃ at 10℃ / min, and the initial oxidation temperature is calculated from the corresponding heat release;

[0078] The microcomputer-controlled electro-hydraulic servo high-temperature end face friction tester (product of Jinan Shunma Test Instrument Co., Ltd.) is used to test the friction coefficient of each group of lubricating greases at 300℃, and the friction pair is C40 cement block and 35CrMnSiA steel material, respectively. 1g of each group of lubricating greases is coated on the surface of the steel friction pair, and the friction pair is loaded into the tester. The test conditions are set on the computer: speed 100r / min, load 300N, test temperature 300℃, test time 20min, close the heating furnace, wait for the temperature to rise to the test temperature, start the test, and close the heating after the test is completed. The average friction coefficient in 20min is obtained;

[0079] The test results are shown in Table 1:

[0080] Table 1

[0081] Item Example 3 Example 4 Example 5 Comparative Example 3 Comparative Example 4 Drop point (°C) 352 357 358 352 350 Flame retardant test Did not burn Did not burn Did not burn Burned Burned Initial oxidation temperature (°C) 235.2 236.8 237.4 232.4 228.5 Average coefficient of friction 0.171 0.164 0.162 0.170 0.235

[0082] As can be seen from Table 1, the greases obtained in Examples 3-5 not only have good lubricating properties, but also have high dropping point, flame retardation, and oxidation resistance, etc. compared with Comparative Examples 3 and 4.

[0083] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other present or future technologies can provide. It must be noted that, as used in this specification and the appended claims, the singular form "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Presten and preconceived notions by persons skilled in the art with respect to the methods and compositions disclosed herein should be overcome concerning the present application. Terms used herein should not be construed to perform exclusive or exhaustive functions unless specifically stated as such. Presten and preconceived notions by persons skilled in the art with respect to the methods and compositions disclosed herein should be overcome concerning the present application. Terms used herein should not be construed to perform exclusive or exhaustive functions unless specifically stated as such.

[0084] While embodiments of the application have been shown and described, it is to be understood that the application is not limited to the details of the embodiments described, since numerous further modifications and changes can be apparent to one skilled in the art without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a flame retardant grease, characterized in that: The following steps are involved: S1. Place base oil and diphenylmethane diisocyanate in a reaction kettle, stir at 45-50°C for 5-10 minutes, add mixture a, heat to 110°C, stir and react for 35-40 minutes, then add mixture b, keep warm and stir and react for 10-15 minutes to obtain a base ester; S2. Deionized water, flame retardant component, graphite and calcium fluoride are added to the base ester, the temperature is raised to 210° C. and refined for 2 hours, then cooled to room temperature, a rust inhibitor is added, and the mixture is homogenized using a high-pressure homogenizer at a pressure of 20-30 MPa, followed by degassing to obtain a flame retardant grease; The flame retardant component is prepared by the following steps: Add DOPO-based monomer, alkali lignin, potassium carbonate and DMF into a three-necked flask, heat to 80°C and stir for 10-20 minutes, add 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane and react at a constant temperature for 48 hours to obtain a flame retardant component; The DOPO-based monomer contains one alcoholic hydroxyl group, three phenolic hydroxyl groups, and a DOPO structure; Mixture a is prepared by the following steps: Add base oil and urea into the reactor at a mass ratio of 29.5:1.1, and stir and mix at a temperature of 135-140°C for 20-30 minutes; Mixture b is prepared by the following steps: Add base oil and octadecylamine into the reactor at a mass ratio of 29.5:10.3, and stir at a temperature of 55-60°C for 10-20 minutes.

2. The method for preparing a flame-retardant grease according to claim 1, characterized in that: The mass ratio of base oil, diphenylmethane diisocyanate, mixture a, mixture b, deionized water, flame retardant component, graphite, calcium fluoride and rust inhibitor is 29.5:9.5:30.6:39.8:0.2-0.4:7-10:7:7:0.1-0.

5.

3. The method for preparing a flame-retardant grease according to claim 1, characterized in that: The usage ratio of DOPO-based monomer, alkali lignin, potassium carbonate, DMF and 1,3-bis(chloromethyl)-1,1,3,3-tetramethyldisiloxane is 7.4-8.0 g: 3.2-4.0 g: 6.5 g: 100-200 mL: 4.6-5.2 g.

4. The method for preparing a flame-retardant grease according to claim 1, characterized in that: DOPO-based monomers are prepared by the following steps: DOPO, 2,3,4-trihydroxybenzaldehyde and ethylene glycol methyl ether were added to a three-necked flask, nitrogen was introduced for protection, the temperature was first raised to 90°C and kept for 30 minutes, and then the temperature was raised to 140°C and stirred for reaction for 4-6 hours to obtain a DOPO-based monomer.

5. The method for preparing a flame-retardant grease according to claim 4, characterized in that: The molar ratio of DOPO and 2,3,4-trihydroxybenzaldehyde is 1:

1.

6. A flame retardant grease, characterized in that: Prepared by the preparation method according to any one of claims 1 to 5.