Base rubber suitable for conductive silicone rubber for high-voltage cable accessories, conductive silicone rubber and preparation method and application of conductive silicone rubber

Abstract

The invention relates to the technical field of power transmission equipment materials, and discloses a base rubber suitable for conductive silicone rubber, the base rubber comprises a base rubber 1 and a base rubber 2, the base rubber 1 contains 100 parts of vinyl-terminated silicone oil, 6-12 parts of hexamethyldisilazane, 1-3 parts of water, and 30-50 parts of fumed silica; the base rubber 2 contains 100 parts of vinyl-terminated silicone oil, 20-70 parts of base rubber 1, 1-4 parts of a dispersing agent, 1-10 parts of carbon nanotubes, 1-50 parts of conductive carbon black and 0.01-2 parts of a pH buffer solution; according to the conductive silicone rubber prepared from the base rubber, through the synergistic effect of the carbon black and the carbon nanotubes, the problems that a single carbon black formula is prone to black grinding and poor in color fastness and a pure carbon nanotube system is high in viscosity and poor in processability are solved, and the final product has excellent conductivity, low friction, no fading and good processing fluidity. In addition, the addition of the pH buffer solution significantly improves the storage stability of the A / B rubber, so that the hardness and vulcanization speed of the mixed rubber material after long-term storage are consistent with those of the fresh rubber material. The invention further discloses conductive silicone rubber prepared from the base rubber and an application method and application of the conductive silicone rubber.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power transmission equipment materials, and specifically discloses a base rubber for conductive silicone rubber for high-voltage cable accessories, the conductive silicone rubber, and a preparation method and application thereof. BACKGROUND

[0002] In modern power transmission systems, high-voltage cables undertake the key task of efficiently and stably transmitting a large amount of electric energy. High-voltage transmission has been widely applied in the fields of long-distance and large-capacity power transmission, long-distance submarine cable or large-city underground cable power transmission, and power distribution networks, due to its advantages of small line loss, large transmission capacity, and high operating stability. As an indispensable part of a high-voltage cable transmission system, the performance of a high-voltage cable accessory directly relates to the safe and stable operation of the entire transmission system. The cable accessory not only needs to ensure normal transmission of electric energy, but also needs to effectively disperse the electric field concentration phenomenon at the cable terminal head, which requires it to have high insulation strength, good sealing performance, excellent mechanical strength, storage stability, and reliable conductor connection performance, and other excellent characteristics.

[0003] Chinese Patent CN 110845851 B, which is a prior application of the present applicant, discloses a liquid conductive adhesive for power cable accessories and a preparation method thereof. The liquid conductive adhesive is prepared from the following raw materials in mass parts: 50-70 parts of vinyl silicone oil; 0-5 parts of polyvinyl silicone oil, and not zero; 0-10 parts of hydrogen-containing silicone oil, and not zero; 10-30 parts of fumed silica; 10-30 parts of conductive carbon black; 2-6 parts of hexamethyldisilazane; 4-10 parts of methylhexadecyl dimethoxysilane; 0-500 ppm of inhibitor; 0-15 ppm of platinum catalyst; and 0.5-3 parts of distilled water. In the scheme, only a single carbon black conductive system is used, and an excessive amount of the carbon black will cause black grinding and poor color fastness, and the storage stability is also not ideal.

[0004] Therefore, the present application needs to solve the technical problem of providing a conductive silicone rubber with excellent conductivity, good color fastness, low friction and no discoloration, and excellent storage stability. SUMMARY

[0005] The present application aims to provide a base glue suitable for conductive silicone rubber for high-voltage cable accessories, which comprises base glue A and base glue B, and contains both carbon black and carbon nanotubes as conductive fillers in the formula of the base glue, and the synergistic effect of carbon black and carbon nanotubes is utilized to overcome the problem of excessive carbon black addition resulting in black grinding and poor color fastness in the single carbon black formula system; and the defects of high viscosity and poor processability of the pure carbon nanotube system are avoided; and finally the conductive silicone rubber obtained has excellent conductivity and low friction without discoloration; in addition, a pH buffer is added to the base glue, which can greatly increase the storage stability of the prepared A glue and B glue, so that the hardness and vulcanization speed of the conductive silicone rubber obtained by mixing the A glue and B glue after long-term storage are almost the same as those of the fresh glue.

[0006] Meanwhile, the present application also discloses a conductive silicone rubber prepared based on the base glue, a preparation method and use thereof.

[0007] To achieve the object of the present application, the following technical solutions are adopted:

[0008] A base glue suitable for conductive silicone rubber for high-voltage cable accessories, which comprises base glue 1 and base glue 2, and contains 100 parts of end-vinyl silicone oil, 6-12 parts of hexamethyldisilazane, 1-3 parts of water, and 30-50 parts of fumed silica in the base glue 1 by mass fraction;

[0009] The base glue 2 contains 100 parts of end-vinyl silicone oil, 20-70 parts of base glue 1, 1-4 parts of a dispersant, 0.1-10 parts of carbon nanotubes, 0.1-50 parts of conductive carbon black, and 0.01-2 parts of a pH buffer.

[0010] Preferably, the specific surface area of the conductive carbon black is 60-1500 m 2 / g.

[0011] The carbon nanotubes are multi-walled carbon nanotubes or single-walled carbon nanotubes, and the diameter is 2-50 nm.

[0012] The pH buffer is one or a combination of oxalic acid / sodium oxalate buffer, citric acid / sodium citrate buffer, and sodium hydrogen phosphate / sodium dihydrogen phosphate buffer with a pH value of 6-7.

[0013] Preferably, the specific surface area of the fumed silica is 200-380 m 2 / g.

[0014] Preferably, the dispersant is one or a combination of hydroxyl silicone oil, dimethyldimethoxysilane, KH570, and KH560.

[0015] In addition, the present invention discloses a conductive silicone rubber for high-voltage cable accessories, which is composed of A rubber and B rubber. By mass parts, the A rubber contains 100 parts of the base rubber 2 as described above, 30-60 parts of the base rubber 1 as described above, 0.5-2 parts of platinum catalyst, 5-20 parts of vinyl-terminated silicone oil, and 1-5 parts of polyvinyl silicone oil.

[0016] The B-type adhesive contains 100 parts of the base adhesive 2 as described above, 30-60 parts of the base adhesive 1 as described above, 0.1-0.8 parts of reaction inhibitor, 2-11 parts of vinyl-terminated silicone oil, 1-5 parts of polyvinyl silicone oil, and 3-9 parts of hydrogen-containing silicone oil.

[0017] The mass ratio of adhesive A to adhesive B is 1:1.

[0018] Preferably, the vinyl content of the terminal vinyl silicone oil is 0.1-1.0 wt%; and the vinyl content of the polyvinyl silicone oil is 2-30 wt%.

[0019] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.3-1.6 wt%.

[0020] Preferably, the reaction inhibitor is one or more combinations of 1-ethynylcyclohexanol, 2-methyl-3-butynol, and 3-methyl-dodecynol.

[0021] Furthermore, this invention also discloses a method for preparing the conductive silicone rubber as described above, the specific steps of which are as follows:

[0022] S1: Preparation of Base Gel 1

[0023] S11: Add 70 parts of vinyl-terminated silicone oil, 6-12 parts of hexamethyldisilazane and 1-3 parts of water into an internal mixer and mix for 10-15 minutes at a speed of 20-50 RPM and room temperature.

[0024] S12: Divide 30-50 parts of fumed silica into 5-7 parts and put them into the internal mixer in sequence. Before each part is put in, confirm that the material in the internal mixer has formed agglomerates. After all the fumed silica has been put in, mix for 1 hour at a speed of 20-50 RPM and a temperature of ≤100℃.

[0025] S13: Add 15 parts of vinyl-terminated silicone oil to a mixer, heat to 140-150℃, vacuum to ≤-0.08MPa, and keep at a constant temperature for 3-4 hours; add another 15 parts of vinyl-terminated silicone oil to the mixer and let it cool naturally to room temperature to obtain base rubber 1.

[0026] S2: Preparation of Base Gel 2

[0027] S21: Add 70 parts of vinyl-terminated silicone oil, 20-70 parts of base rubber 1 and 1-4 parts of dispersant into an internal mixer and mix for 10-15 minutes at room temperature with a speed of 20-50 RPM.

[0028] S22: Add 0.1-10 parts of carbon nanotubes into an internal mixer, and divide 0.1-50 parts of conductive carbon black into 5-7 parts and add them into the internal mixer in sequence. Before each part is added, confirm that the material in the internal mixer has formed agglomerates. After all the conductive carbon black has been added, mix for 1 hour at a speed of 20-50 RPM and a temperature of ≤100℃.

[0029] S23: Add 15 parts of vinyl-terminated silicone oil to a mixer, heat to 140-150℃, vacuum to ≤-0.08MPa, and keep at a constant temperature for 3-4 hours; add another 15 parts of vinyl-terminated silicone oil to the mixer, cool naturally to 80℃, add 0.01-2 parts of pH buffer solution, and finally cool naturally to room temperature to obtain base rubber 2.

[0030] S3: Preparation of Glue A

[0031] Add 100 parts of base adhesive 2, 20-70 parts of base adhesive 1, 0.5-2 parts of platinum catalyst, 5-20 parts of vinyl-terminated silicone oil and 1-5 parts of polyvinyl silicone oil to a mixing tank, evacuate to ≤-0.08MPa, stir at a stirring speed of 10-40R and a temperature of less than 100℃ for 1 hour, filter after completion to obtain adhesive A;

[0032] S4: Preparation of Glue B

[0033] Add 100 parts of base adhesive 2, 20-70 parts of base adhesive 1, 0.1-0.8 parts of reaction inhibitor, 2-11 parts of vinyl-terminated silicone oil, 1-5 parts of polyvinyl silicone oil and 3-9 parts of hydrogen-containing silicone oil to a mixing tank, evacuate to ≤-0.08MPa, stir at a stirring speed of 10-40R and a temperature of less than 100℃ for 1 hour, filter after completion to obtain adhesive B;

[0034] S5: Preparation of conductive silicone rubber

[0035] Mix A and B adhesives at a mass ratio of 1:1, cure at 105±10℃ for 10-20 min, and then vulcanize at 200℃ for 4 h to obtain the conductive silicone rubber.

[0036] Finally, this invention discloses the use of the conductive silicone rubber described above in the manufacture of high-voltage cable accessories.

[0037] The beneficial effects of this invention are:

[0038] The base rubber provided by this invention includes base rubber 1 and base rubber 2. The formulation of the base rubber contains two conductive fillers: carbon black and carbon nanotubes. By utilizing the synergistic effect of carbon black and carbon nanotubes, the problems of blackening and poor color fastness caused by excessive carbon black addition in a single carbon black formulation system are overcome. Furthermore, the defects of high viscosity and poor processability of pure carbon nanotube systems are avoided. The final conductive silicone rubber has the characteristics of excellent conductivity, low friction and no color fading, and good processing fluidity. In addition, a pH buffer solution is added to the base rubber, which can greatly increase the storage stability of the prepared A and B rubbers. This allows the hardness and vulcanization speed of the conductive silicone rubber obtained by mixing A and B rubbers after long-term storage to be almost the same as that of the fresh rubber. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the color fastness test method;

[0040] Figure 2 The image shows the color fastness test results for Example 1;

[0041] Figure 3 The image shows the color fastness test results for Example 2;

[0042] Figure 4 The image shows the color fastness test results for Example 3;

[0043] Figure 5 The image shows the color fastness test results for Comparative Example 1.

[0044] Figure 6 The image shows the color fastness test results for Comparative Example 2.

[0045] Figure 7 The image shows the color fastness test results for Comparative Example 3. Detailed Implementation

[0046] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0047] Product Information

[0048] Single-walled carbon nanotubes: Manufacturer: Beijing Deco Island Gold Technology Co., Ltd., Grade: CNT100;

[0049] Multi-walled carbon nanotubes: Manufacturer: Shenzhen Yizhipeng Technology Co., Ltd., Grade: Carbon nanotube 210T;

[0050] Conductive carbon black: Manufacturer: Shanghai Haiyi Science & Trade Co., Ltd., Grade: SUPER P LI.

[0051] Example 1

[0052] A conductive silicone rubber for high-voltage cable accessories, comprising the following components by weight: The base rubber 1 formulation:

[0053] 2 parts water;

[0054] 100 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0055] 40 parts of fumed silica (specific surface area 250 m²) 2 / g);

[0056] 10 parts of hexamethyldisilazane;

[0057] The formulation of base adhesive 2:

[0058] Two multi-walled carbon nanotubes (50 nm in diameter);

[0059] 20 parts of conductive carbon black (specific surface area of ​​100 m²) 2 / g);

[0060] pH buffer solution: 0.2 parts of oxalic acid-sodium oxalate solution (pH=6.8);

[0061] 100 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0062] 140 parts of the above base adhesive

[0063] 4 parts dispersant (hydroxyl silicone oil, viscosity 10 mPa·s);

[0064] A-type glue formula:

[0065] The above-mentioned base adhesive 2 100 parts

[0066] The above-mentioned base adhesive 1 45 parts

[0067] 10 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0068] 4 parts of polyvinyl silicone oil (vinyl content 4.8 wt%);

[0069] 6 parts of hydrogen-containing silicone oil (0.6 wt% hydrogen content);

[0070] 0.8 parts platinum catalyst;

[0071] B-type glue formula:

[0072] The above-mentioned base adhesive 2 100 parts

[0073] The above-mentioned base adhesive 1 45 parts

[0074] 4 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0075] 4 parts of polyvinyl silicone oil (vinyl content 4.8 wt%);

[0076] 6 parts of hydrogen-containing silicone oil (0.6 wt% hydrogen content);

[0077] 0.5 parts of the reaction inhibitor (2-methyl-3-butynol).

[0078] The preparation method is as follows:

[0079] S1: Preparation of Base Gel 1

[0080] S11: Add 70 parts of vinyl-terminated silicone oil, 10 parts of hexamethyldisilazane and 2 parts of water into an internal mixer and mix for 12 minutes at a speed of 35 RPM and room temperature.

[0081] S12: Divide 40 parts of fumed silica into 5 parts and put them into the internal mixer in sequence. Before each part is put in, confirm that the material in the internal mixer has formed agglomerates. After all the fumed silica has been put in, mix at a speed of 35 R and a temperature of 90°C for 1 hour.

[0082] S13: Add 15 parts of vinyl-terminated silicone oil to a mixer, heat to 145°C, vacuum to ≤-0.08MPa, and keep at a constant temperature for 3.5 hours; add another 15 parts of vinyl-terminated silicone oil to the mixer and let it cool naturally to room temperature to obtain base rubber 1.

[0083] S2: Preparation of Base Gel 2

[0084] S21: Add 70 parts of vinyl-terminated silicone oil, 40 parts of base rubber 1 and 4 parts of dispersant into an internal mixer and mix for 15 minutes at a speed of 50 RPM and room temperature.

[0085] S22: Add 1 part of carbon nanotubes into the internal mixer, and divide 20 parts of conductive carbon black into 6 parts and add them into the internal mixer in sequence. Before each part is added, confirm that the material in the internal mixer has formed a clump. After all the conductive carbon black has been added, mix at a speed of 40R and a temperature of 100℃ for 1 hour.

[0086] S23: Add 15 parts of vinyl-terminated silicone oil to a mixer, heat to 140°C, vacuum to ≤-0.08MPa, and keep at a constant temperature for 3 hours; add another 15 parts of vinyl-terminated silicone oil to the mixer, cool naturally to 80°C, add 0.2 parts of pH buffer solution, and finally cool naturally to room temperature to obtain base rubber 2.

[0087] S3: Preparation of Glue A

[0088] Add 100 parts of base adhesive 2, 45 parts of base adhesive 1, 0.8 parts of platinum catalyst, 10 parts of vinyl-terminated silicone oil and 4 parts of polyvinyl silicone oil to a mixing tank, evacuate to ≤-0.08MPa, stir at a stirring speed of 30R and a temperature of 80℃ for 1h, filter after completion to obtain adhesive A.

[0089] S4: Preparation of Glue B

[0090] Add 100 parts of base adhesive 2, 45 parts of base adhesive 1, 0.5 parts of reaction inhibitor, 5 parts of vinyl-terminated silicone oil, 3 parts of polyvinyl silicone oil and 6 parts of hydrogen-containing silicone oil to a mixing tank, evacuate to ≤-0.08MPa, stir at a stirring speed of 30R and a temperature of 80℃ for 1 hour, filter after completion to obtain adhesive B.

[0091] S5: Preparation of conductive silicone rubber

[0092] Mix adhesive A and adhesive B at a mass ratio of 1:1, cure at 110°C for 20 minutes, and then vulcanize in two stages at 200°C for 4 hours to obtain the conductive silicone rubber.

[0093] Example 2

[0094] A conductive silicone rubber for high-voltage cable accessories contains the following components by weight:

[0095] The formulation of base adhesive 1:

[0096] 2 parts water;

[0097] 100 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0098] 35 parts of fumed silica (specific surface area 250 m²) 2 / g);

[0099] 10.5 parts of hexamethyldisilazane;

[0100] The formulation of base adhesive 2:

[0101] 10 parts of single-walled carbon nanotubes (50 nm in diameter);

[0102] 1 part conductive carbon black (specific surface area 100m²) 2 / g);

[0103] pH buffer solution: 2 portions of citric acid-sodium citrate solution (pH=7.0);

[0104] 100 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0105] 1 30 parts of the above base adhesive

[0106] Dispersant 4 parts (dimethyldimethoxysilane);

[0107] A-type glue formula:

[0108] The above-mentioned base adhesive 2 100 parts

[0109] 1 30 parts of the above base adhesive

[0110] 25 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0111] Five parts of polyvinyl silicone oil (vinyl content 4.8 wt%);

[0112] 2.0 parts platinum catalyst;

[0113] B-type glue formula:

[0114] The above-mentioned base adhesive 2 100 parts

[0115] 1 30 parts of the above base adhesive

[0116] 16 parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0117] Five parts of polyvinyl silicone oil (vinyl content 4.8 wt%);

[0118] 9 parts of hydrogen-containing silicone oil (0.6 wt% hydrogen content);

[0119] 0.8 parts of the reaction inhibitor (2-methyl-3-butynol).

[0120] The preparation method is basically the same as in Example 1, except that the proportions of the terminal vinyl silicone oil in each step are as follows:

[0121] S11: 70 copies;

[0122] S13: 15 portions;

[0123] S21: 70 copies;

[0124] S23: 15 portions; 15 portions;

[0125] S3:25;

[0126] S4:16.

[0127] Example 3

[0128] A conductive silicone rubber for high-voltage cable accessories, comprising the following components by weight: The base rubber 1 formulation:

[0129] 1 part water;

[0130] 100 parts of vinyl-terminated silicone oil (vinyl content 0.2 wt%);

[0131] 30 parts of fumed silica (specific surface area 250 m²) 2 / g);

[0132] 8 parts of hexamethyldisilazane;

[0133] The formulation of base adhesive 2:

[0134] One multi-walled carbon nanotube (10 nm in diameter);

[0135] 50 parts of conductive carbon black (specific surface area of ​​100 m²) 2 / g);

[0136] pH buffer solution: 0.01 parts of sodium hydrogen phosphate-sodium dihydrogen phosphate solution (pH=6.0);

[0137] 100 parts of vinyl-terminated silicone oil (vinyl content 0.2 wt%);

[0138] 1 30 parts of the above base adhesive

[0139] 1 part dispersant (KH570);

[0140] A-type glue formula:

[0141] The above-mentioned base adhesive 2 100 parts

[0142] 150 parts of the above base adhesive

[0143] Nine parts of vinyl-terminated silicone oil (vinyl content 0.3 wt%);

[0144] One part of polyvinyl silicone oil (vinyl content 4.8 wt%);

[0145] 1.0 part of platinum catalyst;

[0146] B-type glue formula:

[0147] The above-mentioned base adhesive 2 100 parts

[0148] 150 parts of the above base adhesive

[0149] Two parts of vinyl-terminated silicone oil (vinyl content 0.2 wt%);

[0150] Two parts of polyvinyl silicone oil (vinyl content 10.0 wt%);

[0151] 6 parts of hydrogen-containing silicone oil (0.3 wt% hydrogen content);

[0152] 0.6 parts of the reaction inhibitor (3-methyl-dodecynol).

[0153] The preparation method is basically the same as in Example 1, except that the proportions of the terminal vinyl silicone oil in each step are as follows:

[0154] S11: 70 copies;

[0155] S13: 15 portions;

[0156] S21: 70 copies;

[0157] S23: 15 portions; 15 portions;

[0158] S3: 9;

[0159] S4:2.

[0160] Comparative Example 1

[0161] It is basically the same as Example 1, except that pH buffer was not added to the raw materials.

[0162] Comparative Example 2

[0163] The method is basically the same as in Example 1, except that conductive carbon black was not added to the raw materials and the mass fraction of multi-walled carbon nanotubes was 22 parts.

[0164] Comparative Example 3

[0165] The method is basically the same as in Example 1, except that multi-walled carbon nanotubes were not added to the raw materials and the mass fraction of conductive carbon black was 22 parts.

[0166] Performance testing

[0167] Test using the following methods;

[0168] Appearance: Visual inspection;

[0169] Viscosity: DIN 53019-1;

[0170] Shore hardness: ISO 48-4;

[0171] AC volume resistivity: ISO 1853;

[0172] T90 vulcanization time: ISO 6502;

[0173] Colorfastness test: such as Figure 1 As shown, the Martindale abrasion tester was used for testing. The vulcanized test piece was subjected to a pressure of 12 kPa and rubbed repeatedly with wool cloth 200 times. The cloth was then removed and the color of the residual adhesive on the cloth was observed. The darker the color, the easier it was for the test piece to fade during the rubbing process.

[0174] The prepared conductive silicone rubber was tested immediately, and the test results are shown in Table 1.

[0175] Table 1 Test Data of Fresh Conductive Silicone Rubber

[0176]

[0177]

[0178] The prepared A and B rubbers were stored for one year before being mixed and vulcanized. The vulcanized conductive silicone rubber was then tested.

[0179] The test results are shown in Table 2.

[0180] Table 2 Test data of conductive silicone rubber after 1 year of storage

[0181]

[0182] The color fastness test results of Examples 1-3 and Comparative Examples 1-3 are as follows: Figures 2 to 7 As shown.

[0183] Data Analysis

[0184] from Figures 1 to 6 As can be seen from Table 1, the conductive silicone rubbers of Examples 1 to 3 contain both carbon black and carbon nanotubes as conductive fillers, and have a low AC volume resistivity, indicating that they have good conductivity; in addition, they have moderate viscosity, good processability, good color fastness, and do not fade with low friction.

[0185] The conductive fillers in the conductive silicone rubbers of Comparative Examples 2 and 3 contain only carbon nanotubes or conductive carbon black. It can be seen that although the AC volume resistivity of Comparative Example 2 is low, its viscosity is extremely high; while the color fastness of Comparative Example 3 is extremely poor, it is easy to shed black, and its AC volume resistivity is high, resulting in poor conductivity.

[0186] As can be seen from Table 2, the data of Example 1 and Comparative Example 1 show that after one year of storage, the Shore hardness of Comparative Example 1 without added pH buffer solution decreased significantly, and the T90 curing time increased substantially, while the Shore hardness and T90 curing time of Example 1 remained almost unchanged, indicating that it has good storage stability.

[0187] In summary, the conductive silicone rubber of this invention utilizes the synergistic effect of carbon black and carbon nanotubes to overcome the problems of blackening and poor color fastness caused by excessive carbon black addition in single carbon black formulation systems; it also avoids the defects of high viscosity and poor processability of pure carbon nanotube systems; the final conductive silicone rubber has the characteristics of excellent conductivity, low friction and no color fading, and good processing fluidity; in addition, the addition of pH buffer to the base rubber can greatly increase the storage stability of the prepared A and B rubbers, so that the hardness and vulcanization speed of the conductive silicone rubber obtained by mixing A and B rubbers after long-term storage are almost the same as those of fresh rubber.

[0188] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A base adhesive for conductive silicone rubber used in high-voltage cable accessories, characterized in that, The base adhesive includes base adhesive 1 and base adhesive 2. By mass, base adhesive 1 contains 100 parts of vinyl-terminated silicone oil, 6-12 parts of hexamethyldisilazane, 1-3 parts of water, and 30-50 parts of fumed silica. The base adhesive 2 contains 100 parts of vinyl-terminated silicone oil, 20-70 parts of base adhesive 1, 1-4 parts of dispersant, 1-10 parts of carbon nanotubes, 1-50 parts of conductive carbon black, and 0.01-2 parts of pH buffer solution.

2. The base adhesive according to claim 1, characterized in that, The specific surface area of ​​the conductive carbon black is 60-1500 m². 2 / g; The carbon nanotubes mentioned are multi-walled carbon nanotubes or single-walled carbon nanotubes with a diameter of 2-50 nm. The pH buffer solution is one or more combinations of oxalic acid / sodium oxalate buffer, citric acid / sodium citrate buffer, and sodium hydrogen phosphate / sodium dihydrogen phosphate buffer with a pH of 6-7.

3. The base adhesive according to claim 1, characterized in that, The specific surface area of ​​the fumed silica is 200-380 m². 2 / g.

4. The base adhesive according to claim 1, characterized in that, The dispersant is one or more of hydroxyl silicone oil, dimethyldimethoxysilane, KH570, and KH560.

5. A conductive silicone rubber for high-voltage cable accessories, characterized in that, Composed of adhesive A and adhesive B, wherein adhesive A contains 100 parts of the base adhesive as described in claim 1 and 30-60 parts of the base adhesive as described in claim 1, by weight. The base adhesive 1 as described in claim 1, 0.5-2 parts platinum catalyst, 5-20 parts vinyl-terminated silicone oil, and 1-5 parts polyvinyl silicone oil; The B-type adhesive contains 100 parts of the base adhesive as described in claim 1 and 30-60 parts of... The base adhesive 1 as described in claim 1, 0.1-0.8 parts of reaction inhibitor, 2-11 parts of vinyl-terminated silicone oil, 1-5 parts of polyvinyl silicone oil, and 3-9 parts of hydrogen-containing silicone oil; The mass ratio of adhesive A to adhesive B is 1:

1.

6. The conductive silicone rubber according to claim 5, characterized in that, The vinyl content of the terminal vinyl silicone oil is 0.1-1.0 wt%; the vinyl content of the polyvinyl silicone oil is 2-30 wt%.

7. The conductive silicone rubber according to claim 5, characterized in that, The hydrogen content of the hydrogen-containing silicone oil is 0.3-1.6 wt%.

8. The conductive silicone rubber according to claim 5, characterized in that, The reaction inhibitor is one or more combinations of 1-ethynylcyclohexanol, 2-methyl-3-butynol, and 3-methyl-dodecynol.

9. The method for preparing conductive silicone rubber according to any one of claims 5-8, characterized in that, include: Preparation of base adhesive 1 Add vinyl-terminated silicone oil, hexamethyldisilazane and water into an internal mixer and mix for 10-15 minutes at a speed of 20-50 RPM and room temperature. Add fumed silica to the internal mixer and confirm that the material in the internal mixer has formed agglomerates. After all the fumed silica has been added, mix it at a speed of 20-50 RPM and a temperature of ≤100℃ for 1 hour. Add the vinyl-terminated silicone oil to the internal mixer, heat it to 140-150℃, evacuate it to ≤-0.08MPa, and keep it at the same temperature for 3-4 hours; add the vinyl-terminated silicone oil to the internal mixer again, and let it cool naturally to room temperature to obtain base rubber 1. Preparation of base adhesive 2 Add the vinyl-terminated silicone oil, base rubber 1, and dispersant into a mixer and mix for 10-15 minutes at a speed of 20-50 RPM and room temperature. Carbon nanotubes are added into the internal mixer, and conductive carbon black is added into the internal mixer. After confirming that the materials in the internal mixer have formed agglomerates and all the conductive carbon black has been added, the mixture is internally mixed for 1 hour at a speed of 20-50 RPM and a temperature of ≤100℃. Add the vinyl-terminated silicone oil into a mixer, heat it to 140-150℃, vacuum it to ≤-0.08MPa, and keep it at a constant temperature for 3-4 hours; add the vinyl-terminated silicone oil to the mixer again, let it cool naturally to 80℃, add pH buffer solution, and finally let it cool naturally to room temperature to obtain base rubber 2. Preparation of Glue A Add base glue 2, base glue 1, platinum catalyst, vinyl-terminated silicone oil and polyvinyl silicone oil to a mixing tank, evacuate to ≤-0.08MPa, stir at a stirring speed of 10-40R and a temperature of less than 100℃ for 1h, filter after completion to obtain glue A; Preparation of Glue B Add base glue 2, base glue 1, reaction inhibitor, vinyl-terminated silicone oil, polyvinyl silicone oil and hydrogen-containing silicone oil to a mixing tank, evacuate to (≤-0.08MPa), stir at a stirring speed of 10-40R and a temperature of less than 100℃ for 1 hour, filter after completion to obtain glue B; Preparation of conductive silicone rubber Mix A and B adhesives at a mass ratio of 1:1, cure at 105±10℃ for 10-20 min, and then vulcanize at 200℃ for 4 h to obtain the conductive silicone rubber.

10. Use of the conductive silicone rubber as described in any one of claims 5-8 in the manufacture of high-voltage cable accessories.

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