Modified MQ silicon resin, preparation method thereof and sealing grease

Abstract

The invention provides modified MQ silicon resin, a preparation method thereof, sealing grease and modified MQ silicon resin, the structure of the modified MQ silicon resin is # imgabs0 #, R1, R2, R3 and R4 are siloxane respectively, and R5, R6, R7 and R8 are phosphate ester groups or thioether groups respectively. The modified MQ silicon resin is of a star-shaped structure and contains phosphate groups and / or thioether groups, when the modified MQ silicon resin is applied to the sealing grease, the sealing grease has higher shear stability and adhesiveness, and the water washing resistance of the sealing grease is improved; moreover, phosphate groups or / and thioether groups can form a layer of boundary lubricating film composed of phosphorus-containing and / or sulfur-containing micromolecules and metal oxides on the metal surface, so that the metal surface is smooth and flat, the catalytic action of metal on oxidation is effectively hindered, the corrosion of corrosive substances on the metal surface is reduced, and the service life of the metal surface is prolonged. And a protective layer with low shear strength can be formed, so that the purpose of reducing surface friction and loss of a metal friction pair is achieved.

Description

Technical Field

[0001] The present application belongs to the technical field of lubrication and sealing materials, and more specifically, to a modified MQ silicone resin and a preparation method thereof and a sealing grease. Background Art

[0002] There are many kinds of sealing greases, and the process design of each sealing grease is designed according to the working needs of specific equipment. The main function of sealing grease is sealing, but the working environment of equipment varies greatly. Some equipment has high pressure, some has high temperature, some has low temperature, some works in water environment, and some works in acid and alkali corrosion environment.

[0003] When waterproof sealing grease is used for lubrication and sealing of moving parts and various sliding parts in water environment, it must have waterproof, lubricating and sealing properties. In addition, the requirements for sealing grease include:

[0004] 1. Strong ability to adhere to metal; 2. Low volatility, no corrosion to metal and plastic; 3. Has certain high and low temperature resistance, does not leak under the specified higher operating temperature conditions, does not freeze at low temperatures, and keeps the lubrication mechanism flexible; 4. Has excellent resistance to water erosion; 5. Resistant to aging, good chemical stability, not easily oxidized and decomposed, long service life; 6. Good colloid stability, not easy to separate from oil; 7. The grease components should not contain nutrients for the growth of microorganisms, and will not grow mold.

[0005] However, traditional waterproof sealing greases often have poor adhesion to metals and poor wear resistance. After long-term use, their shear resistance becomes increasingly poor, causing grease loss and bearing corrosion. Summary of the invention

[0006] Based on this, the purpose of this application is to provide a modified MQ silicone resin to solve the technical problems in the prior art that traditional waterproof sealing grease has poor adhesion and wear resistance to metal, and after long-term use, its shear resistance becomes increasingly poor, causing grease loss and bearing corrosion.

[0007] Another object of the present application is to provide a method for preparing modified MQ silicone resin.

[0008] Another object of the present application is to provide a sealing grease.

[0009] In order to achieve the above-mentioned invention object, the technical solution of this application is as follows:

[0010] A modified MQ silicone resin has the structure:

[0011]

[0012] Among them, R1, R2, R3, and R4 are siloxanes respectively, and R5, R6, R7, and R8 are phosphate groups or thioether groups respectively.

[0013] Optionally, the structures of R1, R2, R3, and R4 are respectively

[0014] In one of the above, R1, R2, R3, and R4 are the same or different; and / or,

[0015] The structures of R5, R6, R7 and R8 are

[0016] One of, R5, R6, R7, R8 are the same or different.

[0017] And, a method for preparing a modified MQ silicone resin, comprising the following steps:

[0018] Mixing a hydrogen-containing MQ silicone resin, a vinyl monomer containing P and / or S, a solvent, and a catalyst to obtain a mixed solution;

[0019] The mixed solution is placed under an inert atmosphere for distillation reaction to remove the solvent, thereby obtaining a modified MQ silicone resin.

[0020] Optionally, the vinyl monomer includes at least one of dimethyl vinyl phosphate, triallyl phosphate, and ethyl vinyl sulfide.

[0021] Optionally, the molar ratio of hydrogenated MQ silicone resin to vinyl monomer is (1.0-1.1):1.

[0022] Optionally, the solvent includes at least one of toluene, xylene, and petroleum ether.

[0023] Optionally, the mass of the solvent is 5%-15% of the total mass of the mixed solution.

[0024] Optionally, the catalyst is at least one of compounds of platinum, palladium, nickel and rhodium.

[0025] Optionally, the mass of the catalyst is 0.1%-1% of the total mass of the mixed solution.

[0026] And, a sealing grease comprising the modified MQ silicone resin.

[0027] Optionally, the sealing grease further comprises silicone oil, a thickener and an additive, and the weight proportions of the modified MQ silicone resin, silicone oil, the thickener and the additive are as follows:

[0028] 20-50 parts of modified MQ silicone resin;

[0029] Silicone oil 40-70 parts;

[0030] Thickener 5-40 parts;

[0031] Additives 0-5 parts.

[0032] Optionally, the silicone oil is one of benzyl silicone oil, methyl silicone oil, dimethyl silicone oil, hydrogen-containing silicone oil, and hydrocarbon silicone oil, or a mixture of several of them.

[0033] Optionally, the viscosity of the silicone oil at 25° C. is 100-500000 cst.

[0034] Optionally, the thickener is at least one of hydrophobic fumed silica, PTFE (polytetrafluoroethylene), zinc oxide, and calcium carbonate.

[0035] Optionally, the additive is at least one of barium dinonylnaphthalenesulfonate and benzotriazole.

[0036] The beneficial effects of this application are:

[0037] The modified MQ silicone resin provided in the present application has a star-shaped structure and contains a phosphate group and / or a thioether group. When applied to a sealing grease, the sealing grease has higher shear stability and adhesion, and improves the water scouring resistance of the sealing grease; moreover, the phosphate group and / or the thioether group can form a boundary lubricating film composed of phosphorus-containing and / or sulfur-containing small molecules and metal oxides on the metal surface, making the metal surface smooth and flat, effectively hindering the catalytic effect of the metal on oxidation, reducing the corrosion of the metal surface by corrosive substances, and forming a protective layer with low shear strength, thereby achieving the purpose of reducing the friction and loss on the surface of the metal friction pair;

[0038] The preparation method of the modified MQ silicone resin provided in the present application can prepare a modified MQ silicone resin with a stable structure, and the steps are simple and easy to operate;

[0039] The sealing grease provided in the present application effectively improves the adhesion and wear resistance to metals and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, in which:

[0041] Figure 1 This is a structural test diagram of the modified MQ silicone resin provided in Example 1 of the present application. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0043] The present application embodiment provides a modified MQ silicone resin, the structure of which is:

[0044]

[0045] Among them, R1, R2, R3, and R4 are siloxanes respectively, and R5, R6, R7, and R8 are phosphate groups or thioether groups respectively.

[0046] The modified MQ silicone resin provided in the embodiment of the present application has a star-shaped structure and contains a phosphate group and / or a thioether group. When applied to sealing grease, the sealing grease has higher shear stability and adhesion, and improves the water scouring resistance of the sealing grease. Moreover, the phosphate group and / or the thioether group can form a boundary lubricating film composed of phosphorus-containing and / or sulfur-containing small molecules and metal oxides on the metal surface, making the metal surface smooth and flat, effectively hindering the catalytic effect of the metal on oxidation, reducing the corrosion of corrosive substances on the metal surface, and forming a protective layer with low shear strength, thereby achieving the purpose of reducing the friction and loss of the metal friction pair surface.

[0047] The MQ silicone resin in the present application is composed of a single functional link (R3SiO 1 / 2 M) and tetrafunctional chain (SiO 4 / 2 That is, a special organic / inorganic hybrid polysiloxane composed of Q).

[0048] In some embodiments of the present application, the structures of R1, R2, R3, and R4 are respectively In one of the above, R1, R2, R3, and R4 are the same or different, that is, R1, R2, R3, and R4 may be the same or different.

[0049] The structures of R5, R6, R7 and R8 are In one of the above, R5, R6, R7, and R8 are the same or different, and R5, R6, R7, and R8 may be the same or different.

[0050] The present invention provides a method for preparing the modified MQ silicone resin, which comprises the following steps:

[0051] S1: mixing hydrogen-containing MQ silicone resin, vinyl monomer containing P and / or S, solvent and catalyst to obtain a mixed solution.

[0052] In some embodiments, the structure of the hydrogenated MQ silicone resin is:

[0053]

[0054] The structures of R1, R2, R3 and R4 are In one of the above, R1, R2, R3, and R4 are the same or different, that is, R1, R2, R3, and R4 may be the same or different.

[0055] In some embodiments, the vinyl monomer includes at least one of vinyl dimethyl phosphate, triallyl phosphate, and ethyl vinyl sulfide, that is, one, two, or three vinyl monomers can be selected for the reaction. When one vinyl monomer is selected for the reaction, R5, R6, R7, and R8 of the modified MQ silicone resin are the same. When multiple vinyl monomers are selected for the reaction, the structures of R5, R6, R7, and R8 obtain corresponding groups according to the selected vinyl monomers.

[0056] The structure of vinyl dimethyl phosphate is:

[0057]

[0058] The structure of triallyl phosphate is:

[0059]

[0060] The structure of ethyl vinyl sulfide is:

[0061]

[0062] In some embodiments, the molar ratio of the hydrogenated MQ silicone resin to the vinyl monomer is (1.0-1.1):1. According to the structure of the modified MQ silicone resin, the molar ratio of R1 and R2 is 1:1. Selecting hydrogenated MQ silicone resins with similar or equal molar ratios to react with vinyl monomers is beneficial to the introduction of R1 and R2 with equal molar ratios on the core group of the modified MQ silicone resin.

[0063] In some embodiments, the solvent includes at least one of toluene, xylene, and petroleum ether, which provides a solution environment for the reaction of the hydrogenated MQ silicone resin and the vinyl monomer and does not participate in the reaction. In some preferred embodiments, the solvent is toluene and / or xylene.

[0064] In some embodiments, the mass of the solvent is 5%-15% of the total mass of the mixed solution. The solvent plays a role in dissolving the reactants and reaction products. If the solvent is too little, for example, less than 5% of the total mass of the mixed solution, the dissolution effect may not be ideal; if the solvent is too much, for example, greater than 15% of the total mass of the mixed solution, it will increase the difficulty of distillation.

[0065] In some embodiments, the catalyst is at least one of a compound of platinum, palladium, nickel and rhodium. Preferably, the compound of platinum, palladium, nickel and rhodium is a complex of platinum, palladium, nickel and rhodium. In some preferred embodiments, the catalyst is a platinum complex with high activity, such as H2PtCl6.

[0066] In some embodiments, the mass of the catalyst is 0.1%-1% of the total mass of the mixed solution. If the catalyst content is too low, for example, less than 0.1% of the total mass of the mixed solution, the hydrosilylation reaction is slow; as the catalyst content increases, the reaction rate is accelerated, but if the catalyst content continues to increase, for example, greater than 1% of the total mass of the mixed solution, the molecular weight of the modified MQ silicone resin increases, and the steric hindrance effect may inhibit the continued increase in the reaction rate.

[0067] S2: placing the mixed solution under an inert atmosphere for distillation reaction to remove the solvent and obtain a modified MQ silicone resin.

[0068] In the embodiment of the present application, the reaction principle of the preparation method of the modified MQ silicone resin is:

[0069]

[0070] When the vinyl monomer is vinyl dimethyl phosphate, the reaction equation is as follows:

[0071]

[0072] Optionally, the distillation reaction temperature generally depends on the solvent used. When the solvent is xylene and / or petroleum ether, the distillation reaction temperature is 80°C-150°C; when toluene is used as the solvent, the distillation temperature is 100°C-115°C.

[0073] In some embodiments, the distillation reaction container of the mixed solution is a three-necked flask, and the reaction process is carried out under stirring in a nitrogen atmosphere. The three-necked flask is equipped with a nitrogen fixing port, a magnetic stirrer and a condenser. During the stirring process, the hydrogenated MQ silicone resin gradually reacts with the vinyl monomer to obtain a modified MQ silicone resin dissolved in a solvent, which is then distilled to remove most of the solvent and low-boiling components.

[0074] In some embodiments, the mixing process of hydrogenated MQ silicone resin, vinyl monomer, solvent and catalyst can be: firstly add hydrogenated MQ silicone resin, vinyl monomer and solvent into a three-necked flask respectively, and then add the catalyst into the three-necked flask after removing nitrogen, and then stir at 80℃-90℃ for 4h-5.5h, and then distill at 90℃-150℃ for 1h-3h.

[0075] The method for preparing the modified MQ silicone resin provided in the embodiment of the present application can prepare a modified MQ silicone resin with a stable structure, has simple steps and is easy to operate.

[0076] The embodiment of the present application also provides a sealing grease, including the above-mentioned modified MQ silicone resin, which effectively improves the water erosion resistance, adhesion to metal and wear resistance, and has a good application prospect.

[0077] In some embodiments, the sealing grease further comprises silicone oil, a thickener and an additive, and the weight proportions of the modified MQ silicone resin, silicone oil, the thickener and the additive are as follows:

[0078]

[0079]

[0080] Modified MQ silicone resin and silicone oil are mixed in proportion and used as the base oil of sealing grease to formulate sealing greases of different viscosities. When the proportion of modified MQ silicone resin is high, the adhesion and wear resistance are better.

[0081] The thickener plays a thickening role. With the same base oil viscosity, the higher the thickener ratio, the higher the cone penetration of the sealing grease.

[0082] The additive is mainly a rust inhibitor, which helps to increase the rust-proof effect of the sealing grease.

[0083] In some embodiments, the silicone oil is one or a mixture of benzyl silicone oil, methyl silicone oil, dimethyl silicone oil, hydrogen silicone oil, and hydrocarbon silicone oil.

[0084] In some embodiments, the viscosity of silicone oil at 25°C is 100-500000 cst. If the viscosity is too low, such as less than 100 cst, the volatility is large and the high temperature performance is poor; if the viscosity is too high, such as greater than 500000 cst, the consistency is large and it is not easy to mix evenly with the thickener.

[0085] In some embodiments, the thickener is at least one of hydrophobic fumed silica, PTFE (polytetrafluoroethylene), zinc oxide, and calcium carbonate. These thickeners have good compatibility in silicon-based base oils.

[0086] In some embodiments, the additive is at least one of barium dinonylnaphthalenesulfonate and benzotriazole, which increases the anti-rust property of the sealing grease. These rust inhibitors have good compatibility with silicon-based base oils and have a good anti-rust effect.

[0087] The present application also provides a method for preparing sealing grease, comprising the following steps:

[0088] P1: Add modified MQ silicone resin, silicone oil and additives into a stirring vessel.

[0089] P2: Start the agitator and stir at a speed of 30r / min-1000r / min for 0.5h-3h to obtain a mixed material.

[0090] P3: Add thickener to the mixture, heat to 60℃-120℃, and stir at a speed of 30r / min-1000r / min for 0.5h-3h.

[0091] After adding the thickener, stir at 60℃-120℃ to facilitate the full mixing of the mixed material and the thickener. If the temperature is too low, for example, below 60℃, the viscosity of MQ silicone resin is large, and it is difficult to mix evenly with silicone oil and thickener, and the efficiency is low; if the temperature is too high, for example, above 120℃, some small molecules in additives and other components may volatilize, resulting in material loss and affecting the physical properties of the sealing grease.

[0092] P4: Vacuum degassing, the vacuum degree is -0.06MPa-(-0.09)MPa, vacuum for 0.5h-1h, and obtain sealing grease.

[0093] It is understandable that after vacuuming, the prepared sealing grease is taken out, cooled to room temperature, and ground as needed.

[0094] The method for preparing the sealing grease in the embodiment of the present application formulates a suitable reaction process according to the properties of the modified MQ silicone resin, silicone oil, thickener, and additives to prepare a sealing grease with excellent adhesion and anti-wear properties.

[0095] The following examples are used to illustrate.

[0096] Example 1

[0097] The preparation method of the modified MQ silicone resin of this embodiment comprises the following steps:

[0098] S1: 50 g of hydrogenated MQ silicone resin, 35 g of vinyl dimethyl phosphate and 10 mL of toluene were added into a 250 mL three-necked flask equipped with a nitrogen fixing port, a magnetic stirrer and a condenser.

[0099] The structure of hydrogenated MQ silicone resin is:

[0100]

[0101] The structures of R1, R2, R3 and R4 are

[0102] S2: After venting nitrogen for 20 minutes, add 0.5 g of hydrosilation catalyst H2PtCl6 into the three-necked flask, stir at 80°C for 5 hours, and then distill at 110°C for 2 hours to remove toluene and low-boiling components to obtain modified MQ silicone resin.

[0103] The structure of the MQ silicone resin in this embodiment is:

[0104]

[0105] The structures of R1, R2, R3 and R4 are

[0106] The infrared spectrum of the modified MQ silicone resin of this embodiment is as follows: Figure 1 As shown, 2960cm -1 The peak at 1252 cm is the stretching vibration peak of Si-CH3. -1 and 837cm -1 The sharp peak at 1080cm is the characteristic absorption peak of Si-CH3. -1 The peak at 1180cm is the asymmetric stretching absorption peak of Si-O-Si. -1 and 1159cm -1 The appearance of the characteristic absorption peak of phosphate ester indicates that the phosphate ester group has reacted with the hydrogen-containing MQ silicone resin to obtain the MQ silicone resin modified by the phosphate ester group.

[0107] The sealing grease of this embodiment includes the following components in parts by weight:

[0108]

[0109] The preparation of the sealing grease of the present embodiment comprises the following steps:

[0110] P1: Add modified MQ silicone resin, silicone oil and additives into the mixing tank according to the proportion.

[0111] P2: Start the stirrer and stir at a speed of 800r / min for 1 hour.

[0112] P3: After the above materials are completely mixed, add the thickener, heat to 100°C, stir at 500r / min for 2h, and mix evenly.

[0113] P4: Vacuum degassing, vacuum degree is -0.08MPa, vacuum for 1 hour.

[0114] P5: Take out and cool to room temperature, grind 4 times, filter and package.

[0115] Example 2

[0116] The preparation method of the modified MQ silicone resin and sealing grease in this embodiment is the same as that in embodiment 1, except that:

[0117] The sealing grease of this embodiment includes the following components in parts by weight:

[0118]

[0119] Example 3

[0120] The preparation method of the modified MQ silicone resin and sealing grease in this embodiment is the same as that in embodiment 1, except that:

[0121] The sealing grease of this embodiment includes the following components in parts by weight:

[0122]

[0123] Example 4

[0124] The preparation method of the modified MQ silicone resin and sealing grease in this embodiment is the same as that in embodiment 1, except that:

[0125] The sealing grease of this embodiment includes the following components in parts by weight:

[0126]

[0127]

[0128] Example 5

[0129] MQ Silicone Resin The preparation method of the modified MQ silicone resin of this embodiment comprises the following steps:

[0130] S1: 50 g of hydrogenated MQ silicone resin, 22 g of triallyl phosphate and 10 mL of toluene were added into a 250 mL three-necked flask equipped with a nitrogen fixing port, a magnetic stirrer and a condenser.

[0131] S2: After venting nitrogen for 20 minutes, add 0.5 g of hydrosilation catalyst H2PtCl6 into the three-necked flask, stir at 80°C for 5 hours, and then distill at 110°C for 2 hours to remove toluene and low-boiling components to obtain modified MQ silicone resin.

[0132] The sealing grease of this embodiment includes the following components in parts by weight:

[0133]

[0134] The preparation of the sealing grease of the present embodiment comprises the following steps:

[0135] P1: Add modified MQ silicone resin, silicone oil and additives into the mixing tank according to the proportion.

[0136] P2: Start the stirrer and stir at a speed of 800r / min for 1 hour.

[0137] P3: After the above materials are completely mixed, add the thickener, heat to 100°C, stir at 500r / min for 2h, and mix evenly.

[0138] P4: Vacuum degassing, vacuum degree is -0.08MPa, vacuum for 1 hour.

[0139] P5: Take out and cool to room temperature, grind 4 times, filter and package.

[0140] Example 6

[0141] MQ Silicone Resin The preparation method of the modified MQ silicone resin of this embodiment comprises the following steps:

[0142] S1: 50 g of hydrogenated MQ silicone resin, 15 g of ethyl vinyl sulfide and 10 mL of toluene were added into a 250 mL three-necked flask equipped with a nitrogen fixing port, a magnetic stirrer and a condenser.

[0143] S2: After venting nitrogen for 20 minutes, add 0.5 g of hydrosilation catalyst H2PtCl6 into the three-necked flask, stir at 80°C for 5 hours, and then distill at 110°C for 2 hours to remove toluene and low-boiling components to obtain modified MQ silicone resin.

[0144] The sealing grease of this embodiment includes the following components in parts by weight:

[0145]

[0146] The preparation of the sealing grease of the present embodiment comprises the following steps:

[0147] P1: Add modified MQ silicone resin, silicone oil and additives into the mixing tank according to the proportion.

[0148] P2: Start the stirrer and stir at a speed of 800r / min for 1 hour.

[0149] P3: After the above materials are completely mixed, add the thickener, heat to 100°C, stir at 500r / min for 2h, and mix evenly.

[0150] P4: Vacuum degassing, vacuum degree is -0.08MPa, vacuum for 1 hour.

[0151] P5: Take out and cool to room temperature, grind 4 times, filter and package.

[0152] Example 7

[0153] The preparation method of the modified MQ silicone resin of this embodiment comprises the following steps:

[0154] S1: 50 g of hydrogenated MQ silicone resin, 20 g of vinyl dimethyl phosphate, 10 g of triallyl phosphate and 10 mL of toluene were added into a 250 mL three-necked flask equipped with a nitrogen fixing port, a magnetic stirrer and a condenser.

[0155] S2: After venting nitrogen for 20 minutes, add 0.5 g of hydrosilation catalyst H2PtCl6 into the three-necked flask, stir at 80°C for 5 hours, and then distill at 110°C for 2 hours to remove toluene and low-boiling components to obtain modified MQ silicone resin.

[0156] The sealing grease of this embodiment includes the following components in parts by weight:

[0157]

[0158] The preparation of the sealing grease of the present embodiment comprises the following steps:

[0159] P1: Add modified MQ silicone resin, silicone oil and additives into the mixing tank according to the proportion.

[0160] P2: Start the stirrer and stir at a speed of 800r / min for 1 hour.

[0161] P3: After the above materials are completely mixed, add the thickener, heat to 100°C, stir at 500r / min for 2h, and mix evenly.

[0162] P4: Vacuum degassing, vacuum degree is -0.08MPa, vacuum for 1 hour.

[0163] P5: Take out and cool to room temperature, grind 4 times, filter and package.

[0164] The hydrogen-containing MQ silicone resins used in Examples 5-7 are the same as the hydrogen-containing MQ silicone resin in Example 1.

[0165] Comparative Example 1

[0166] The sealing grease of this comparative example comprises the following components in parts by weight:

[0167] Silicone oil Shin-Etsu RF-50,000 90 parts;

[0168] Thickener Degussa R974 10 parts;

[0169] Additive T706 0.5 parts.

[0170] The preparation method of the sealing grease in this comparative example is the same as that in Example 1.

[0171] Comparative Example 2

[0172] The sealing grease of this comparative example comprises the following components in parts by weight:

[0173] Silicone oil Shin-Etsu RF-50,000 70 parts;

[0174] Thickener Daikin L-5 30 parts;

[0175] Additive T706 0.5 parts.

[0176] Comparative Example 3

[0177] The sealing grease of this comparative example comprises the following components in parts by weight:

[0178]

[0179] The preparation method of the sealing grease in this comparative example is the same as that in Example 1.

[0180] The sealing greases of Examples 1-7 and Comparative Examples 1-3 were tested for performance. The performance testing method is as follows:

[0181] 1. Working cone penetration: refer to GB / T 269 Cone penetration test method for lubricating grease and petroleum grease.

[0182] 2. Anti-wear performance: SHT 0204-1992 Determination of anti-wear performance of grease (four-ball machine method)

[0183] 3. Bearing corrosion (salt spray test): Put a certain amount of sealing grease into the bearing and refer to SH / T 0081 test.

[0184] The test results are shown in Table 1.

[0185] Table 1

[0186]

[0187] From the test results, it can be seen that the wear resistance of the sealing grease in comparative examples 1-3 is poor and stops running after a very short time. The sealing grease in embodiment 1-7 which introduces modified MQ silicone resin can run normally for 3600 seconds and the wear spot diameter is also significantly reduced.

[0188] It can be seen from the salt spray corrosion resistance test results that in Examples 1-7, the sealing grease containing the modified MQ silicone resin was subjected to a 24-hour salt spray test, and the sealing grease did not leak, and the bearings were substantially rust-free.

[0189] In the embodiment of the present application, the modified MQ silicone resin containing a phosphate group or a thioether group is added to the sealing grease, thereby significantly improving the adhesion and wear resistance of the sealing grease.

[0190] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A modified MQ silicone resin, characterized in that: The structure of the modified MQ silicone resin is: Among them, R1, R2, R3, and R4 are siloxanes respectively, and R5, R6, R7, and R8 are phosphate groups or thioether groups respectively.

2. The modified MQ silicone resin according to claim 1, characterized in that: The structures of R1, R2, R3 and R4 are respectively wherein R1, R2, R3, and R4 are the same or different; and / or, The structures of R5, R6, R7 and R8 are respectively In one of the above, R5, R6, R7, and R8 are the same or different.

3. A method for preparing a modified MQ silicone resin, characterized in that: The following steps are involved: Mixing a hydrogen-containing MQ silicone resin, a vinyl monomer containing P and / or S, a solvent, and a catalyst to obtain a mixed solution; The mixed solution is placed under an inert atmosphere for distillation reaction to remove the solvent, thereby obtaining a modified MQ silicone resin.

4. The method for preparing the modified MQ silicone resin according to claim 3, characterized in that: The vinyl monomer includes at least one of vinyl dimethyl phosphate, triallyl phosphate, and ethyl vinyl sulfide; and / or, The molar ratio of the hydrogen-containing MQ silicone resin to the vinyl monomer is (1.0-1.1):

1.

5. The method for preparing the modified MQ silicone resin according to claim 3 or 4, characterized in that: The solvent comprises at least one of toluene, xylene and petroleum ether; and / or, The mass of the solvent is 5%-15% of the total mass of the mixed solution.

6. The method for preparing the modified MQ silicone resin according to claim 3 or 4, characterized in that: The catalyst is at least one of compounds of platinum, palladium, nickel and rhodium; and / or, The mass of the catalyst is 0.1%-1% of the total mass of the mixed solution.

7. A sealing grease, characterized in that: The sealing grease comprises the modified MQ silicone resin according to claim 1.

8. The sealing grease according to claim 7, characterized in that: The sealing grease further comprises silicone oil, thickener and additives, and the weight proportions of the modified MQ silicone resin, silicone oil, thickener and additives are as follows:

9. The sealing grease according to claim 8, characterized in that: The silicone oil is one or a mixture of benzyl silicone oil, methyl silicone oil, dimethyl silicone oil, hydrogen silicone oil, and hydrocarbon silicone oil; and / or, The viscosity of the silicone oil at 25° C. is 100-500000 cst.

10. The sealing grease according to claim 8, characterized in that: The thickener is at least one of hydrophobic fumed silica, PTFE (polytetrafluoroethylene), zinc oxide, and calcium carbonate; and / or, The additive is at least one of barium dinonylnaphthalenesulfonate and benzotriazole.

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