Silicone rubber composition, silicone rubber composite material and preparation method and application thereof

Abstract

The invention relates to a silicone rubber composition, a silicone rubber composite material and a preparation method and application thereof, the silicone rubber composition comprises a component A (100 parts of base rubber, 10-20 parts of a diluent and 0.2-0.7 part of a platinum catalyst), a component B (100 parts of base rubber, 20-60 parts of a diluent, 1-10 parts of a cross-linking agent and 0.2-0.7 part of an inhibitor) and a component C (10-30 parts of a filler and 10-20 parts of a diluent), and the mass ratio of the component A to the component B to the component C is 10: 10: (0.8-1.3). The filling agent is prepared from aluminum hydroxide, graphene nanosheets, chopped glass fibers and kaolin, and the mass ratio of the aluminum hydroxide to the graphene nanosheets to the chopped glass fibers to the kaolin is (10-20): (0.2-1): (1.5-4): (0.5-5). The silicone rubber composite material provided by the invention is good in surface integrity, high in heat resistance and strong in arc resistance and flame retardance, and is suitable for manufacturing composite insulators and anti-pollution flashover coatings.

Description

Technical Field

[0001] The present invention relates to the technical field of disaster prevention and mitigation of power systems, and in particular to a silicone rubber composition, a silicone rubber composite material, and a preparation method and application thereof. Background Art

[0002] Silicone rubber is widely used in composite insulators and anti-pollution flashover coatings for high-voltage transmission lines due to its excellent hydrophobicity and weather resistance. However, existing silicone rubber materials still have two key technical bottlenecks in long-term operation. Silicone rubber is prone to local carbonization and erosion due to dry-band arcing in polluted environments. The liquid silicone rubber used to fill lightning protection insulators has poor heat dissipation and is prone to excessive thermal stress, which seriously affects the service life of the lightning protection insulators. In the existing technology, the performance can be partially improved by adding inorganic fillers (such as micron / nano aluminum hydroxide and silicon dioxide), but the following problems still exist: the high amount of flame retardant added leads to a decrease in the mechanical properties of the material; it is difficult for a single filler to simultaneously improve the arc resistance and flame retardant properties; the introduction of high thermal conductivity fillers increases the electrical conductivity and aggravates the leakage current. Therefore, there is an urgent need to develop a silicone rubber composite material with high arc resistance and flame retardancy, excellent electrochemical properties and corrosion resistance. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a silicone rubber composition, a silicone rubber composite material, and a preparation method and application thereof. The silicone rubber composite material provided by the present invention can synergistically improve the arc tracking resistance, corrosion resistance, and flame retardant properties of silicone rubber through the synergistic effect of the three components, while also having excellent electrical properties.

[0004] In a first aspect, the present invention provides a silicone rubber composition, wherein the silicone rubber composition comprises, by mass, a component A, a component B, and a component C in a mass ratio of 10:10:(0.8-1.3) (e.g., 10:10:0.8, 10:10:0.9, 10:10:1, 10:10:1.1, 10:10:1.2, 10:10:1.3, etc.), and the compositions of component A, component B, and component C are as follows:

[0005] Component A: 100 parts of base rubber, 10-20 parts (e.g., 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 20 parts, etc.) of diluent, 0.2-0.7 parts (e.g., 0.2 parts, 0.5 parts, 0.6 parts, 0.7 parts, etc.) of platinum catalyst;

[0006] Component B: 100 parts of base gum, 20-60 parts (e.g., 20, 30, 40, 50, 60, etc.) of diluent, 1-10 parts (e.g., 1, 3, 5, 7, 9, etc.) of cross-linking agent, 0.2-0.7 parts (e.g., 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, etc.) of inhibitor;

[0007] Component C: 10-30 parts (e.g., 10, 15, 20, 25, 30, etc.) of filler, 10-20 parts (e.g., 10, 12, 14, 16, 18, 20, etc.) of diluent;

[0008] The filler comprises aluminum hydroxide, graphene nanosheets, glass fiber and kaolin, and the mass ratio is (10-20): (0.2-1): (1.5-4): (0.5-5), for example, 10:0.2:1.5:0.5, 15:1:2:1, 20:0.5:4:5, 17:0.3:3:1.5, etc.;

[0009] The base glue comprises vinyl-containing polydimethylsiloxane and fumed silica powder in a mass ratio of 10:(2-3), such as 10:2, 10:2.2, 10:2.4, 10:2.6, 10:2.8, 10:3, etc.

[0010] The present invention introduces kaolin to cooperate with aluminum hydroxide (ATH), graphene (GN), and glass fiber (GF) to construct a quaternary reinforcement system, wherein aluminum hydroxide can improve thermal conductivity, release water to reduce temperature when decomposed, thereby reducing electrical tracking and erosion; graphene can form a carbon layer during the ablation process, which serves as a thermal barrier and improves thermal conductivity at the same time; glass fiber can provide structural support, form a three-dimensional network, enhance mechanical properties, and inhibit crack propagation and electrical tracking path extension; kaolin can inhibit leakage current, reduce the formation of surface carbonization path, crack propagation, and electrical tracking path extension. Through the synergistic coordination of the above-mentioned fillers and the coordination of components A, B, and C, a silicone rubber composite material with synergistically improved arc resistance, erosion resistance, and flame retardant properties is finally obtained.

[0011] As a preferred technical solution of the present invention, the specific surface area of the fumed silica powder is 220-250m 2 / g, for example 220m 2 / g, 230m 2 / g, 240m 2 / g, 250m 2 / g, etc.

[0012] As a preferred technical solution of the present invention, the diluent is vinyl-containing polydimethylsiloxane.

[0013] As a preferred technical solution of the present invention, the platinum catalyst is a platinum-vinylsiloxane complex.

[0014] As a preferred technical solution of the present invention, the cross-linking agent is hydrogen-containing silicone oil.

[0015] As a preferred technical solution of the present invention, the inhibitor is selected from divinyltetramethyldisiloxane and tetravinyltetramethylcyclotetrasiloxane, or a mixture of the two.

[0016] As a preferred technical solution of the present invention, the vinyl content of the vinyl-containing polydimethylsiloxane in the base glue and the diluent is 0.15-0.18%, for example, 0.15%, 0.16%, 0.17%, 0.18%, etc.

[0017] As a preferred technical solution of the present invention, the viscosity of the vinyl-containing polydimethylsiloxane in the base glue and the diluent at 25°C is 3000-8000mPa·s, for example, 3000mPa·s, 4000mPa·s, 5000mPa·s, 6000mPa·s, 7000mPa·s, 8000mPa·s, etc.

[0018] As a preferred technical solution of the present invention, the mass percentage of hydrogen in the hydrogen-containing silicone oil is 0.5-0.8%, for example, 0.5%, 0.6%, 0.7%, 0.8%, etc., and the viscosity of the hydrogen-containing silicone oil at 25°C is 30-100mPa·s, for example, 30mPa·s, 40mPa·s, 50mPa·s, 60mPa·s, 70mPa·s, 80mPa·s, 90mPa·s, 100mPa·s, etc.

[0019] As a preferred technical solution of the present invention, the particle size of the aluminum hydroxide in the filler is 3 to 7 μm, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, etc., the diameter of the graphene nanosheets is 3 to 7 μm, for example, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, etc., the glass fiber is chopped glass fiber, the length of the glass fiber is 50 to 200 μm, for example, 50 μm, 100 μm, 150 μm, 200 μm, etc., the diameter of the glass fiber is 9-13 μm, for example, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, etc., and the particle size of the kaolin is 0.5 to 2 μm, for example, 0.5 μm, 1 μm, 1.5 μm, 2 μm, etc.

[0020] In a second aspect, the present invention provides a silicone rubber composite material, which is obtained by cross-linking the silicone rubber composition described in the first aspect.

[0021] In a third aspect, the present invention provides a method for preparing the silicone rubber composite material according to the second aspect, comprising the following steps:

[0022] Preparation of base rubber: Mix vinyl-containing polydimethylsiloxane and fumed silica in a uniform mass ratio;

[0023] Preparation of component A: Mix the base rubber, diluent and platinum catalyst evenly according to the mass ratio;

[0024] Preparation of component B: Mix the base glue, diluent, cross-linking agent and inhibitor in a uniform mass ratio;

[0025] Preparation of component C: Mix the dried aluminum hydroxide, graphene nanosheets, glass fiber, kaolin and diluent in a mass ratio;

[0026] Vacuum degassing: Mix the prepared components A, B and C according to the mass ratio, and vacuum degas to obtain a mixed glue;

[0027] Curing and molding: curing the mixed rubber at 145-155° C. until it is completely cross-linked to obtain the silicone rubber composite material.

[0028] As a preferred technical solution of the present invention, the base rubber is mixed under the condition of vacuuming at 150° C. to an absolute pressure of ≤0.08 MPa.

[0029] As a preferred technical solution of the present invention, the mixing method in the preparation of the base glue, component A, component B and component C is stirring for 1 to 2 hours, such as 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, etc.

[0030] As a preferred technical solution of the present invention, the drying condition is that the moisture content of aluminum hydroxide, graphene nanosheets, glass fibers and kaolin is controlled at <0.1%.

[0031] In some embodiments of the present invention, aluminum hydroxide, graphene nanosheets, glass fibers, and kaolin are placed in an oven at 80±5° C. and dried for 12 hours to control the moisture content to <0.1%.

[0032] As a preferred technical solution of the present invention, the vacuum degassing condition is to evacuate to an absolute pressure of ≤1kPa and maintain it for 10 to 15 minutes until there are no bubbles, for example, 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, etc.

[0033] In a fourth aspect, the present invention provides an application of the silicone rubber composite material described in the second aspect or the silicone rubber composite material prepared by the preparation method described in the third aspect, wherein the silicone rubber composite material is used in the manufacture of composite insulators and anti-pollution flashover coatings for high-voltage transmission lines.

[0034] The technical solution provided by the embodiment of the present invention has the following advantages compared with the existing technology:

[0035] The silicone rubber composite material provided by the present invention has excellent surface integrity, high heat resistance, strong arc and flame resistance, corrosion resistance, and excellent electrical properties. High-voltage transmission line composite insulators and anti-pollution flashover coatings prepared using the silicone rubber composite material provided by the present invention have improved electrochemical performance and service life, as well as outstanding economic performance. DETAILED DESCRIPTION

[0036] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0037] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0038] The chemical reagents used in the embodiments of the present invention are all commercially available. The sources of some of the chemical reagents are listed below:

[0039] Vinyl polydimethylsiloxane, Hesheng Silicon Industry Co., Ltd.;

[0040] Platinum-vinylsiloxane complex, Anhui Zhengjie High-tech Materials Co., Ltd.;

[0041] Hydrogenated silicone oil, Hubei Hengjingrui Chemical Co., Ltd.

[0042] Example 1

[0043] This embodiment provides a silicone rubber composite material and a preparation method:

[0044] Raw material ratio:

[0045] Component A: 100g of base rubber, 15g of diluent, 0.5g of platinum catalyst (platinum-vinylsiloxane complex);

[0046] Component B: 100g of base glue, 40g of diluent, 5g of crosslinking agent, 0.5g of inhibitor (tetravinyltetramethylcyclotetrasiloxane);

[0047] Component C: filler 17.8g (aluminum hydroxide 12g, graphene nanosheets 0.8g, glass fiber 3g, kaolin 2g), diluent 15g.

[0048] Among them, the base rubber is composed of vinyl-containing polydimethylsiloxane and fumed silica in a mass ratio of 100:25. The viscosity of vinyl-containing polydimethylsiloxane is 7000mPa·s, and the specific surface area of fumed silica is 240m2 / g; the viscosity of vinyl-containing polydimethylsiloxane in the diluent is 5000mPa·s, and the vinyl content is 0.16%; the hydrogen content in the cross-linking agent hydrogenated silicone oil is 0.6%, and the viscosity is 50mPa·s; the aluminum hydroxide D50 particle size in the filler is 5μm; the graphene nanosheet D50 particle size is 5μm; the glass fiber length is 150μm, the diameter is 10μm; the kaolin D50 particle size is 1μm.

[0049] The preparation steps are as follows:

[0050] Preparation of base rubber: Vinyl-containing polydimethylsiloxane and fumed silica were stirred at 150°C and vacuum 0.08 MPa for 1.5 hours to obtain a uniform base rubber.

[0051] Preparation of component A: Take the base rubber, diluent and platinum catalyst and stir them at room temperature for 1 hour, and then degas in vacuum.

[0052] Preparation of component B: Mix the base glue with the diluent, cross-linking agent and inhibitor for 1 hour.

[0053] Preparation of component C: Aluminum hydroxide, graphene nanosheets, glass fibers, and kaolin were dried at 80° C. for 12 h (moisture content <0.1%) and mixed with a diluent for 1 h.

[0054] Mixing and degassing: Component A: component B: component C are mixed in a mass ratio of 10:10:1, and vacuum degassing is performed to a pressure of ≤1 kPa, and maintained for 10 minutes to obtain a mixed glue.

[0055] Curing and molding: placing the mixed rubber in a mold at 150° C. and curing for 30 minutes to obtain the silicone rubber composite material.

[0056] Example 2

[0057] This embodiment provides a silicone rubber composite material and a preparation method:

[0058] Raw material ratio:

[0059] Component A: 100g of base rubber, 10g of diluent, 0.5g of platinum catalyst (platinum-vinylsiloxane complex);

[0060] Component B: 100g of base glue, 20g of diluent, 1g of crosslinking agent, 0.2g of inhibitor (divinyltetramethyldisiloxane);

[0061] Component C: filler 30g (aluminum hydroxide 20g, graphene nanosheets 1g, glass fiber 4g, kaolin 5g), diluent 20g.

[0062] Among them, the base rubber is composed of vinyl-containing polydimethylsiloxane and fumed silica in a mass ratio of 100:20, the viscosity of the vinyl-containing polydimethylsiloxane is 3000 mPa·s, and the specific surface area of the fumed silica is 220 m2 / g; the viscosity of the vinyl-containing polydimethylsiloxane in the diluent is 3000 mPa·s, and the vinyl content is 0.18%; the hydrogen content of the cross-linking agent hydrogenated silicone oil is 0.5% and the viscosity is 50 mPa·s; the particle size of each component in the filler is the same as that in Example 1, and the glass fiber length is 50 μm and the diameter is 9 μm.

[0063] Preparation steps: except that the mass ratio of component A: component B: component C is 10:10:0.8, the rest is the same as Example 1.

[0064] Example 3

[0065] This embodiment provides a silicone rubber composite material and a preparation method:

[0066] Raw material ratio:

[0067] Component A: 100g of base rubber, 20g of diluent, 0.7g of platinum catalyst (platinum-vinylsiloxane complex);

[0068] Component B: 100g of base glue, 60g of diluent, 10g of crosslinking agent, 0.7g of inhibitor (tetravinyltetramethylcyclotetrasiloxane and divinyltetramethyldisiloxane);

[0069] Component C: filler 10g (aluminum hydroxide 7g, graphene nanosheets 0.7g, glass fiber 1.1g, kaolin 1.2g), diluent 10g.

[0070] Among them, the base rubber is composed of vinyl-containing polydimethylsiloxane and fumed silica in a mass ratio of 100:30, the viscosity of the vinyl-containing polydimethylsiloxane is 7000 mPa·s, and the specific surface area of the fumed silica is 250 m2 / g; the viscosity of the vinyl-containing polydimethylsiloxane in the diluent is 8000 mPa·s, and the vinyl content is 0.15%; the hydrogen content of the cross-linking agent hydrogenated silicone oil is 0.8% and the viscosity is 50 mPa·s; the particle size of each component in the filler is the same as that in Example 1, and the glass fiber length is 200 μm and the diameter is 13 μm.

[0071] Preparation steps: Except that the mass ratio of component A: component B: component C is 10:10:1.3, the rest is the same as Example 1.

[0072] Comparative Example 1

[0073] This comparative example provides a silicone rubber composite material and a preparation method thereof, which differs from Example 1 in that component C is not added.

[0074] Comparative Example 2

[0075] This comparative example provides a silicone rubber composite material and a preparation method. The difference from Example 1 is that the raw material ratio of component C is: 12g of filler (aluminum hydroxide) and 15g of diluent.

[0076] Comparative Example 3

[0077] This comparative example provides a silicone rubber composite material and a preparation method. The difference from Example 1 is that the raw material ratio of component C is: 12.8g of filler (12g of aluminum hydroxide, 0.8g of graphene nanosheets) and 15g of diluent.

[0078] Comparative Example 4

[0079] This comparative example provides a silicone rubber composite material and a preparation method. The difference from Example 1 is that the raw material ratio of component C is: 15.8g filler (12g aluminum hydroxide, 0.8g graphene nanosheets, 3g glass fiber), and 15g diluent.

[0080] Performance Testing

[0081] Performance tests were performed on Examples 1 to 3 and Comparative Examples 1 to 4. The test methods are as follows:

[0082] Depth of electrical erosion: GB / T 6553-2014 “Test method for assessing resistance to tracking and erosion of electrical insulating materials for use under severe environmental conditions”;

[0083] Leakage current peak: GB / T 16927.1-2011 "High voltage test technology Part 1: General definitions and test requirements";

[0084] Limiting oxygen index: GB / T 10707-2008 "Rubber combustion performance - Oxygen index method";

[0085] Thermal conductivity: GB / T 11205-2009 Rubber - Determination of thermal conductivity - Hot wire method.

[0086] The test results are shown in Table 1:

[0087] Table 1 Performance test results

[0088]

[0089] As can be seen from Table 1, the electrical erosion depth of Example 1 is only 0.9 mm, which is 80.9% lower than that of Comparative Example 1, and lower than that of Comparative Examples 2-4, indicating that its arc erosion resistance is significantly enhanced; the leakage current peak of Example 1 is 4.5 mA, which is much lower than that of Comparative Examples 3 and 4, effectively reducing the safety risk of electrical equipment caused by insulation failure; the limiting oxygen index of Example 1 reaches 38%, which is 46.2% higher than that of Comparative Example 1, meeting the high flame retardant material standard (>30%), and is higher than that of Comparative Examples 2-4, and is particularly suitable for high temperature and high arc environments; the thermal conductivity of Example 1 is 0.412 W / (m·K), which is 116.8% higher than that of Comparative Example 1, and is better than Comparative Examples 2-4, significantly improving the thermal stability of the material in long-term operation.

[0090] In summary, the silicone rubber composite material provided by the present invention significantly improves the electrical corrosion resistance, insulation, flame retardancy and thermal conductivity of silicone rubber. The composite insulators and anti-pollution flashover coatings manufactured using this material have better performance and service life, and more outstanding economic performance.

[0091] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0092] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments described herein, but is to be construed in the widest manner consistent with the principles and novel features disclosed herein.

Claims

1. A silicone rubber composition, characterized in that The silicone rubber composition comprises component A, component B, and component C in a mass ratio of 10:10:(0.8-1.3) in parts by mass, and the compositions of component A, component B, and component C are as follows: Component A: 100 parts of base rubber, 10-20 parts of diluent and 0.2-0.7 parts of platinum catalyst; Component B: 100 parts of base glue, 20-60 parts of diluent, 1-10 parts of cross-linking agent and 0.2-0.7 parts of inhibitor; Component C: 10-30 parts of filler and 10-20 parts of diluent; The filler comprises aluminum hydroxide, graphene nanosheets, glass fiber and kaolin in a mass ratio of (10-20):(0.2-1):(1.5-4):(0.5-5); The base glue comprises vinyl-containing polydimethylsiloxane and fumed silica powder, and the mass ratio is 10:(2-3).

2. The silicone rubber composition according to claim 1, wherein The specific surface area of the fumed silica powder in the base rubber is 220 to 250 m 2 / g.

3. The silicone rubber composition according to claim 1, wherein The diluent is vinyl-containing polydimethylsiloxane; Preferably, the platinum catalyst is a platinum-vinylsiloxane complex; Preferably, the cross-linking agent is hydrogen-containing silicone oil; Preferably, the inhibitor is selected from one or a mixture of divinyltetramethyldisiloxane and tetravinyltetramethylcyclotetrasiloxane.

4. The silicone rubber composition according to claim 1, wherein The vinyl content of the vinyl-containing polydimethylsiloxane in the base glue and the diluent is 0.15-0.18%; Preferably, the viscosity of the vinyl-containing polydimethylsiloxane in the gum base and the diluent at 25° C. is 3000 to 8000 mPa·s.

5. The silicone rubber composition according to claim 3, characterized in that The mass percentage of hydrogen in the hydrogen-containing silicone oil is 0.5-0.8%, and the viscosity of the hydrogen-containing silicone oil at 25° C. is 30-100 mPa·s.

6. The silicone rubber composition according to claim 1, wherein The particle size of the aluminum hydroxide in the filler is 3 to 7 μm, the diameter of the graphene nanosheet is 3 to 7 μm, the glass fiber is chopped glass fiber, the length of the glass fiber is 50 to 200 μm, the diameter of the glass fiber is 9-13 μm, and the particle size of the kaolin is 0.5 to 2 μm.

7. A silicone rubber composite material, characterized in that: The silicone rubber composite material is obtained by cross-linking the silicone rubber composition according to any one of claims 1 to 6.

8. The method for preparing the silicone rubber composite material according to claim 7, wherein: The following steps are involved: base Preparation of glue: Mix vinyl-containing polydimethylsiloxane and fumed silica in a uniform mass ratio; Preparation of component A: Mix the base rubber, diluent and platinum catalyst evenly according to the mass ratio; Preparation of component B: Mix the base glue, diluent, cross-linking agent and inhibitor in a uniform mass ratio; Preparation of component C: Mix the dried aluminum hydroxide, graphene nanosheets, glass fiber, kaolin and diluent in a mass ratio; Vacuum degassing: Mix the prepared components A, B and C according to the mass ratio, and vacuum degas to obtain a mixed glue; Curing and molding: curing the mixed rubber at 145-155° C. until it is completely cross-linked to obtain the silicone rubber composite material.

9. The preparation method according to claim 8, characterized in that The base rubber is mixed under the conditions of vacuuming at 150°C to an absolute pressure of ≤0.08MPa; Preferably, the mixing method in the preparation of the base glue, component A, component B and component C is stirring for 1 to 2 hours; Preferably, the drying condition is that the moisture content of aluminum hydroxide, graphene nanosheets, glass fibers and kaolin is controlled to be less than 0.1%; Preferably, the vacuum degassing condition is to evacuate to an absolute pressure of ≤1 kPa and maintain the pressure for 10 to 15 minutes until no bubbles are left.

10. Use of the silicone rubber composite material according to claim 7 or the silicone rubber composite material prepared by the preparation method according to any one of claims 8 to 9, characterized in that: The silicone rubber composite material is used in the manufacture of composite insulators and anti-pollution flashover coatings for high-voltage transmission lines.

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