Special lubricating grease for ceramic valve core and preparation method thereof

Abstract

The invention discloses special lubricating grease for a ceramic valve core and a preparation method, and relates to the technical field of lubricating grease, the lubricating grease comprises the following components by mass: 50%-90% of base oil, 3%-25% of a thickening agent, 0.1%-3% of a surface treating agent, 5%-20% of a solid lubricant and 0.1%-2.5% of an antioxidant. According to the special lubricating grease for the ceramic valve element and the preparation method, different silicone oils are compounded, so that the wear resistance of the base oil component is improved, and the prepared finished product lubricating grease has relatively wide use temperature range, good waterproof sealing property and stable shearing stability, and also has good lubricating property. The wear resistance of the lubricating grease is superior to that of common silicone oil series lubricating grease, the wear of ceramic materials caused by long-time work can be effectively reduced, and the service life of a ceramic valve element is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating grease, in particular to a lubricating grease special for ceramic valve cores and a preparation method thereof. Background Art

[0002] As the core of the mechanical parts of the water valve, the valve core is usually made of engineering ceramics (i.e. structural ceramics), the main types of which are Al2O3, ZrO2, SiC ceramics, etc. The ceramic valve core is composed of a fixed chip and a movable chip, which changes the relative position of the two friction pairs through relative friction movement to achieve temperature control and flow control of the water flow.

[0003] There are two common forms of ceramic wear, namely adhesive wear and abrasive wear. Adhesive wear occurs because the two friction pairs of the ceramic material used for the valve core are relatively smooth and completely clean. When the two friction pairs come into contact, strong adhesive bonding will occur, resulting in adhesive wear during movement. Abrasive wear occurs because the surface of the ceramic material is microscopically uneven. When the two friction pairs come into contact, abrasive wear will occur.

[0004] Most structural ceramic materials have high hardness and low wear rate. This material feature will greatly increase the life of the water valve under good lubricating medium. However, for ceramic valve cores that are used for a long time (usually 3-4 years) and do not have the conditions for greasing or changing grease, as the ceramic friction pair moves relative to each other, the microscopic plastic flow on the friction surface causes the ceramic valve core to slowly wear, resulting in water leakage. This also puts higher requirements on the anti-wear performance of the lubricating medium.

[0005] Silicone oil has good viscosity-temperature characteristics, excellent oxidation stability, and stable shear stability after grease formation. The key is that under the premise of the same thickener, the waterproofness and sealing properties of silicone oil series grease are significantly higher than those of hydrocarbon grease. However, the lubrication performance of silicone oil is slightly weaker than that of hydrocarbon base oil, resulting in poor anti-wear performance of silicone oil series grease. General silicone oil series grease is difficult to meet the needs of lifelong lubrication of ceramic valve cores. That is, conventional silicone oil series grease has certain limitations in the application of grease in the field of ceramic materials. Summary of the invention

[0006] In view of the problems existing in the above prior art, the present invention provides a composition and preparation method of a special lubricating grease for ceramic valve cores. The finished lubricating grease prepared by using a specific silicone oil compound combination has a wide operating temperature range, good waterproof sealing and stable shear stability, and also has the characteristics of being superior to general silicone oil series grease in anti-wear performance, which can effectively alleviate the wear of ceramic materials and extend the service life of ceramic valve cores.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] In the first aspect, the present invention provides a special lubricating grease for ceramic valve core, which is composed of the following components by mass fraction:

[0009] The base oil is 50% to 90%, the thickener is 3% to 25%, the surface treatment agent is 0.1% to 3%, the solid lubricant is 5% to 20% and the antioxidant is 0.1% to 2.5%.

[0010] Furthermore, the base oil is one or any mixture of dimethyl silicone oil, ethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, and perfluoroalkyl silicone oil, and the kinematic viscosity range of the base oil is 100 mm 2 / s-2500mm 2 / s.

[0011] Furthermore, the thickener is one or any mixture of nano silicon dioxide, nano titanium dioxide, calcium stearate soap, and calcium dodecyl stearate soap, with a specific surface area of ​​100 m 2 / g-1000m 2 / g.

[0012] Furthermore, the surface treatment agent is one or any mixture of siloxane coupling agent KH-570, n-octanol, phosphate ester, and diphenylsilanediol.

[0013] Furthermore, the solid lubricant is one or any mixture of graphite, molybdenum disulfide, boron nitride, polytetrafluoroethylene, and polyethylene wax powder.

[0014] Furthermore, the antioxidant is one or any mixture of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, dioctyldiphenylamine, and dinonyldiphenylamine.

[0015] In a second aspect, the present invention further proposes a method for preparing the above-mentioned special lubricating grease for ceramic valve core, comprising the following steps:

[0016] S1. After 2 / 3 of the base oil and the surface modifier are fully mixed, a thickener is added and stirred at a constant speed under a certain temperature condition;

[0017] S2. Under certain temperature conditions, add solid lubricant while stirring at a constant speed;

[0018] S3, add the remaining amount of base oil, add antioxidant under certain temperature conditions, and stir at a constant speed;

[0019] S4. After cooling to room temperature, grind 2-4 times to obtain a finished product of wear-resistant ceramic valve core grease.

[0020] Furthermore, in step S1, the temperature condition is 120°C-180°C, and the time of uniform stirring reaction is 2h-5h.

[0021] Furthermore, in step S2, the temperature condition is 80°C-120°C, and the time of uniform stirring reaction is 1h-2h.

[0022] Furthermore, in step S3, the temperature condition is 50° C.-80° C., and the time of uniform stirring reaction is 0.5 h-1.5 h.

[0023] The present invention provides a special lubricating grease for ceramic valve core and a preparation method thereof. Compared with the prior art, it has the following beneficial effects:

[0024] The compounding of different silicone oils improves the wear resistance of the base oil component. The finished grease has a wide operating temperature range, good waterproof sealing and stable shear stability. Its anti-wear performance is also superior to that of general silicone oil series greases. It can effectively reduce the wear of ceramic materials caused by long-term work and extend the service life of ceramic valve cores. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention are described in detail below through specific embodiments. However, it should be clearly stated that these embodiments are for illustration only and are not to be construed as limiting the scope of the present invention.

[0026] Example 1

[0027] A method for preparing a special lubricating grease for a ceramic valve core comprises the following steps:

[0028] S1. After fully mixing and stirring 55% of base oil (mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil and perfluoroalkyl silicone oil in a mass ratio of 2:1:1) and 0.5% of silicone coupling agent KH-570, 1.5% of nano-silicon dioxide (specific surface area of ​​200m2 / g) and 8% of calcium stearate were added, the mixture was stirred at a constant speed at 160°C for 3h;

[0029] S2, then lower the temperature to 90°C, add 5% polytetrafluoroethylene, and stir at a constant temperature of 90°C for 1 hour;

[0030] S3, add 27% base oil (mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil, and perfluoroalkyl silicone oil in a mass ratio of 2:1:1), and stir at a constant speed for 0.5h. At a temperature of 60°C, add 1.5% of 2,6-di-tert-butyl-p-cresol and 1.5% of dioctyl diphenylamine, and stir at a constant temperature and constant speed for 0.5h;

[0031] S4, after cooling to room temperature, grind 3 times to obtain the anti-wear ceramic valve core grease.

[0032] Example 2

[0033] A method for preparing a special lubricating grease for a ceramic valve core comprises the following steps:

[0034] S1. After fully mixing and stirring 55% of base oil (a mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil and perfluoroalkyl silicone oil in a mass ratio of 1.5:1.5:1) and 0.5% of silicone coupling agent KH-570, 1.5% of nano-silicon dioxide (specific surface area of ​​200m2 / g) and 8% of calcium stearate were added, the mixture was stirred at a constant speed at 160°C for 3h;

[0035] S2, then lower the temperature to 90°C, add 5% polytetrafluoroethylene, and stir at a constant temperature of 90°C for 1 hour;

[0036] S3, add 27% base oil (mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil and perfluoroalkyl silicone oil in a mass ratio of 1.5:1.5:1), stir at a constant speed for 0.5h, add 1.5% by mass of 2,6-di-tert-butyl-p-cresol and 1.5% by mass of dioctyldiphenylamine at a temperature of 60°C, and stir at a constant temperature and constant speed for 0.5h;

[0037] S4, after cooling to room temperature, grind 3 times to obtain the anti-wear ceramic valve core grease.

[0038] Example 3

[0039] A method for preparing a special lubricating grease for a ceramic valve core comprises the following steps:

[0040] S1. After fully mixing and stirring 55% of base oil (a mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil and perfluoroalkyl silicone oil in a mass ratio of 1.5:1:1.5) and 0.5% of silicone coupling agent KH-570, 1.5% of nano-silicon dioxide (specific surface area of ​​200m2 / g) and 8% of calcium stearate were added, the mixture was stirred at a constant speed at 160°C for 3h;

[0041] S2, then lower the temperature to 90°C, add 5% polytetrafluoroethylene, and stir at a constant temperature of 90°C for 1 hour;

[0042] S3, add 27% base oil (mixed base oil of dimethyl silicone oil, chlorophenyl silicone oil, and perfluoroalkyl silicone oil in a mass ratio of 1.5:1:1.5), and stir at a constant speed for 0.5h. At a temperature of 60°C, add 1.5% of 2,6-di-tert-butyl-p-cresol and 1.5% of dioctyl diphenylamine, and stir at a constant temperature and constant speed for 0.5h;

[0043] S4, after cooling to room temperature, grind 3 times to obtain the anti-wear ceramic valve core grease.

[0044] Comparative Example

[0045] Compared with the embodiment, the difference is that only dimethyl silicone oil is used as the base oil, and no other silicone oil is added for compounding. The preparation steps are as follows:

[0046] S1. After 55% by mass of dimethyl silicone oil and 0.5% by mass of silicone coupling agent KH-570 were fully mixed and stirred, 1.5% by mass of nano-silicon dioxide (specific surface area of ​​200 m2 / g) and 8% by mass of calcium stearate were added, and the mixture was stirred at a constant speed at 160°C for 3 hours;

[0047] S2, then lower the temperature to 90°C, add 5% polytetrafluoroethylene, and stir at a constant temperature of 90°C for 1 hour;

[0048] S3, add 27% dimethyl silicone oil, stir at a constant speed for 0.5h. At 60℃, add 1.5% by mass of 2,6-di-tert-butyl-p-cresol and 1.5% by mass of dioctyldiphenylamine, stir at a constant temperature for 0.5h;

[0049] S4, after cooling to room temperature, grind 3 times to obtain ceramic valve core grease of general silicone oil series.

[0050] Test example

[0051] The performance indicators of the finished greases obtained in Examples 1-3 of the present invention and the comparative examples were measured according to the corresponding test standards. The test results are shown in Table 1.

[0052] Table 1

[0053]

[0054] [1]: After adding lubricating medium, the ceramic valve core material is rubbed 100,000 times in a cycle, and the wear rate is calculated by measuring the mass change before and after weighing.

[0055] Through the test examples, it can be found that the basic parameters (cone penetration, copper sheet corrosion, evaporation loss, dropping point, steel mesh oil separation) of Examples 1-3 are basically the same as those of the comparative example, but there is a large gap in anti-wear performance and material wear rate. The finished grease prepared by the formula of compounded silicone oil is better than the finished grease prepared by only using dimethyl silicone oil in anti-wear performance and material wear rate. This shows that by compounding and mixing silicone oil, the anti-wear performance of the prepared grease can be effectively improved, and the service life of the relevant lubricating parts (ceramic valve core) can be extended.

[0056] In summary, the composition and preparation method of the special grease for ceramic valve core provided by the present invention improve the anti-wear performance of general silicone oil series grease, reduce the wear of related components (ceramic valve core) caused by long-term work, and extend the service life of the ceramic valve core.

Claims

1. A special lubricating grease for ceramic valve core, characterized in that: It is composed of the following components in mass fraction: The base oil is 50% to 90%, the thickener is 3% to 25%, the surface treatment agent is 0.1% to 3%, the solid lubricant is 5% to 20% and the antioxidant is 0.1% to 2.5%.

2. The special lubricating grease for ceramic valve core according to claim 1, characterized in that: The base oil is one or any mixture of dimethyl silicone oil, ethyl silicone oil, methylphenyl silicone oil, chlorophenyl silicone oil, methyl hydrogen silicone oil, and perfluoroalkyl silicone oil, and the kinematic viscosity range of the base oil is 100 mm 2 / s-2500mm 2 / s.

3. The special lubricating grease for ceramic valve core according to claim 1, characterized in that: The thickener is one or any mixture of nano silicon dioxide, nano titanium dioxide, calcium stearate soap, and calcium dodecyl stearate soap, with a specific surface area of ​​100 m 2 / g-1000m 2 / g.

4. The special lubricating grease for ceramic valve core according to claim 1, characterized in that: The surface treatment agent is one or any mixture of siloxane coupling agent KH-570, n-octanol, phosphate ester, and diphenylsilanediol.

5. The special lubricating grease for ceramic valve core according to claim 1, characterized in that: The solid lubricant is one or any mixture of graphite, molybdenum disulfide, boron nitride, polytetrafluoroethylene, and polyethylene wax powder.

6. The special lubricating grease for ceramic valve core according to claim 1, characterized in that: The antioxidant is one or any mixture of 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-p-cresol, dioctyldiphenylamine and dinonyldiphenylamine.

7. A special lubricating grease for ceramic valve core according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: S1. After 2 / 3 of the base oil and the surface modifier are fully mixed, a thickener is added and stirred at a constant speed under a certain temperature condition; S2. Under certain temperature conditions, add solid lubricant while stirring at a constant speed; S3, add the remaining amount of base oil, add antioxidant under certain temperature conditions, and stir at a constant speed; S4. After cooling to room temperature, grind 2-4 times to obtain a finished product of wear-resistant ceramic valve core grease.

8. The method for preparing a special lubricating grease for ceramic valve core according to claim 7, characterized in that: In step S1, the temperature condition is 120° C.-180° C., and the time of uniform stirring reaction is 2 h-5 h.

9. The method for preparing a special lubricating grease for ceramic valve core according to claim 7, characterized in that: In step S2, the temperature condition is 80° C.-120° C., and the time of uniform stirring reaction is 1 h-2 h.

10. The method for preparing a special lubricating grease for ceramic valve core according to claim 7, characterized in that: In step S3, the temperature condition is 50° C.-80° C., and the time of uniform stirring reaction is 0.5 h-1.5 h.

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