阅读说明：本技术 一种绝缘电缆用硅橡胶复合材料及其制备方法 (Silicone rubber composite material for insulated cable and preparation method thereof ) 是由 张倩 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种绝缘电缆用硅橡胶复合材料及其制备方法,属于电缆附件制备技术领域,包括将改性纳米碳化硅、硅橡胶、交联剂四甲氧基硅烷和催化剂二丁基二月桂酸锡共同混合,在室温下固化12-36h得到室温硫化硅橡胶；其中,所用改性碳化硅的制备条件为：将碳化硅纳米颗粒在氮气流下50-90℃脱水1-6h,然后与3-氨基丙基三乙氧基硅烷和氨基磺酸在100-120℃下反应9-24h。产物离心,并用二乙醚与二氯甲烷的混合溶剂洗涤后干燥6-24h得到改性纳米碳化硅。本发明改善了添加纳米碳化硅引起的介电性能下降的问题,改善了硅橡胶的力学性能以及老化后性能保持率的问题。(The invention discloses a silicon rubber composite material for an insulated cable and a preparation method thereof, belonging to the technical field of cable accessory preparation, and comprising the steps of mixing modified nano silicon carbide, silicon rubber, cross-linking agent tetramethoxysilane and catalyst dibutyl tin dilaurate together, and curing at room temperature for 12-36h to obtain room temperature vulcanized silicon rubber; wherein the preparation conditions of the modified silicon carbide are as follows: dehydrating the silicon carbide nano-particles for 1-6h at 50-90 ℃ under nitrogen flow, and then reacting the silicon carbide nano-particles with 3-aminopropyltriethoxysilane and sulfamic acid for 9-24h at 100-120 ℃. And centrifuging the product, washing the product by using a mixed solvent of diethyl ether and dichloromethane, and drying the product for 6 to 24 hours to obtain the modified nano silicon carbide. The invention improves the problem of dielectric property reduction caused by adding nano silicon carbide and the problems of mechanical property and property retention rate after aging of the silicon rubber.)

1. A preparation method of modified nano silicon carbide is characterized in that 3-aminopropyltriethoxysilane and sulfamic acid are used for modifying nano silicon carbide to obtain the modified nano silicon carbide.

2. The method for preparing modified nano silicon carbide according to claim 1, wherein the method comprises the following steps: the addition amount of the 3-aminopropyl triethoxysilane is 80-120 wt% of the nano silicon carbide.

3. The method for preparing modified nano silicon carbide according to claim 1, wherein the method comprises the following steps: the addition amount of the sulfamic acid is 5-50 wt% of the nano silicon carbide.

4. The method for preparing modified nano silicon carbide according to claim 1, wherein the method comprises the following steps: the adding proportion of the 3-aminopropyltriethoxysilane to the sulfamic acid is that the mass ratio of the 3-aminopropyltriethoxysilane to the sulfamic acid is 1: 0.1-0.5.

5. Use of the modified nano-silicon carbide prepared by the method of any one of claims 1 to 4 in the preparation of rubber materials.

6.3-aminopropyl triethoxysilane and sulfamic acid in modifying nanometer silicon carbide.

7. A silicone rubber composite comprising: containing the modified nano-sized silicon carbide prepared by the method of claim 1.

8. A preparation method of a silicone rubber composite material for an insulated cable comprises the following steps: stirring and mixing the modified nano silicon carbide prepared by the method of claim 1, vinyl silicone oil, hydrogen-containing silicone oil, a cross-linking agent and a catalyst together, and curing at room temperature for 12-36h to obtain room-temperature vulcanized silicone rubber; the cross-linking agent is tetramethoxysilane, and the catalyst is dibutyl tin dilaurate.

9. The method according to claim 8, wherein the silicone rubber composite for insulated cables comprises: the addition amount of the modified nano silicon carbide is 5-50 wt% of the vinyl silicone oil.

10. The method according to claim 8, wherein the silicone rubber composite for insulated cables comprises: the volume ratio of the vinyl silicone oil to the hydrogen silicone oil is 1: 0.5-5.

Technical Field

The invention belongs to the technical field of cable accessory preparation, and particularly relates to a silicone rubber composite material for an insulated cable and a preparation method thereof.

Background

In the high voltage power equipment, other parts requiring insulation in contact with air, except for the iron box, are classified into an external insulation category, which includes an indoor and outdoor insulation of indoor equipment and an outdoor insulation of outdoor equipment. After the 70's in the 20 th century, silicone rubber was used as an external insulating material. The silicon rubber material has outstanding electrical insulation performance, weather resistance, and unique hydrophobic and hydrophobic migration performance, the stability of the silicon rubber material can be comparable with that of polytetrafluoroethylene material, and the processability and the bonding performance of the silicon rubber material are superior to those of polytetrafluoroethylene. The main chain of the silicon rubber has no unsaturated bond, and the bond length of Si-O is about 1.5 times of that of C-C bond, and the silicon rubber is not easily degraded and oxidized by oxygen, ozone and ultraviolet rays, so the silicon rubber has excellent ozone aging resistance, weather aging resistance, light aging resistance and thermal oxygen aging resistance. Compared with other rubbers, the influence of corona discharge generated by ozone on the silicon rubber is small, in addition, when the silicon rubber is in wind sand, rainy and ultraviolet irradiation environments for a long time, the physical properties of the silicon rubber are kept unchanged, and aging phenomena such as cracks or degradation and stickiness are not found after outdoor exposure tests for decades.

In a high-voltage direct-current transmission system, a high-voltage direct-current XLPE cable and a high-voltage direct-current cable accessory matched with the high-voltage direct-current XLPE cable need to bear high voltage for a long time, a large amount of space charge accumulation can be formed between the inside of an insulating material and an interface of the insulating material, the local electric field inside the insulating material can be distorted due to the space charge accumulation, and the performance is improved through filling materials.

In the application of the composite insulator, the national standard GB/T19519-2004 of the composite insulator requires that the tracking resistance of the outer insulating material must reach 1A4.5 grade, and the electric erosion depth is less than 2.5mm, but the common silicon rubber cannot meet the requirement. At present, the method for improving the tracking resistance of the silicon rubber mainly comprises the addition of a tracking resistance agent. In recent years, with the vigorous development of nanotechnology and nanocomposite materials, nanocomposite insulating materials show wide application prospects in the field of high-voltage insulation. Compared with the traditional inorganic filler, the nano filler has small addition amount, can improve the tracking resistance of the silicon rubber, and can also improve the mechanical property of the silicon rubber. Surface modifiers are typically used to surface treat and modify the nanofiller.

Disclosure of Invention

The invention aims to provide a preparation method of modified nano silicon carbide, which forms an adsorption molecular layer on the surface of nano silicon carbide and reduces the aggregation and agglomeration of the nano silicon carbide.

The technical scheme adopted by the invention for realizing the purpose is as follows:

a preparation method of modified nano silicon carbide is characterized in that 3-aminopropyltriethoxysilane and sulfamic acid are used for modifying nano silicon carbide to obtain the modified nano silicon carbide. The nano silicon carbide as a nano material has good size effect and large specific surface area, and after being modified by 3-aminopropyltriethoxysilane and sulfamic acid, an adsorption molecular layer is formed on the surface of the nano silicon carbide, so that the aggregation and agglomeration of the nano silicon carbide are reduced, and when the nano silicon carbide is added to form a composite material, the nano silicon carbide is uniformly dispersed in a silicon rubber material, so that the dielectric property of the silicon rubber added with the nano silicon carbide is improved.

In one embodiment of the invention, the preparation method of the modified nano silicon carbide comprises the following steps: dehydrating the silicon carbide nano-particles for 1-6h at 50-90 ℃ under nitrogen flow, and then reacting the silicon carbide nano-particles with 3-aminopropyltriethoxysilane and sulfamic acid for 9-24h at 100-120 ℃. Centrifuging and collecting the product, washing with a mixed solvent of diethyl ether and dichloromethane, and drying at 50-80 deg.C for 6-24 h; the addition amount of the 3-aminopropyltriethoxysilane is 80-120 wt% of the nano silicon carbide, the addition amount of the sulfamic acid is 5-50 wt% of the nano silicon carbide, and the volume ratio of the diethyl ether to the dichloromethane is 1: mixing at a ratio of 0.5-2.

Preferably, the addition amount of the 3-aminopropyl triethoxysilane is 80-120 wt% of the nano silicon carbide. Preferably, the 3-aminopropyltriethoxysilane may be added in an amount of 85-115 wt%, more preferably, the 3-aminopropyltriethoxysilane may also be added in an amount of 87, 90, 100, 110, 112 wt%, and the like.

Preferably, the addition amount of sulfamic acid is 5 to 50 weight percent of the nano silicon carbide. Preferably, the amount of sulfamic acid added may be from 10 to 45 wt.%, more preferably, the amount of sulfamic acid added may also be 10, 20, 30, 40, 45 wt.%, and so forth.

Preferably, the grain size of the nano silicon carbide is 10-100 nm.

Preferably, the ratio of 3-aminopropyltriethoxysilane to sulfamic acid is 1: 0.1-0.5. Preferably, the mass ratio of 3-aminopropyltriethoxysilane to sulfamic acid may be 1: 0.15-0.45, more preferably, the mass ratio of 3-aminopropyltriethoxysilane to sulfamic acid may also be 10, 20, 30, 40, 45 wt%.

Preferably, the preparation temperature of the modified nano silicon carbide is 100-120 ℃, and the reaction time is 9-24 h.

Preferably, the preparation process of the modified nano silicon carbide is in a nitrogen atmosphere.

The invention provides application of modified nano silicon carbide in preparation of rubber materials.

The invention provides application of 3-aminopropyl triethoxysilane and sulfamic acid in uniform dispersion of nano silicon carbide.

The invention provides a silicon rubber composite material which comprises modified nano silicon carbide.

In one embodiment of the present invention, the mixing ratio of diethyl ether to dichloromethane is 1: 0.5-2, preferably, the mixing ratio of diethyl ether to dichloromethane may be 1: 0.8-1.8, e.g., 1: 0.8, 1: 1. 1: 1.3, 1: 1.5, 1: 1.8.

the invention also aims to provide a preparation method of the silicon rubber composite material for the insulated cable, which improves the mechanical property of the silicon rubber added with the modified nano silicon carbide by adding the modified nano silicon carbide, the per-ethyl (carbamyl) carbamate and the hexamethylene diisocyanate.

The technical scheme adopted by the invention for realizing the purpose is as follows:

a preparation method of a silicone rubber composite material for an insulated cable comprises the following steps: adding the modified nano silicon carbide into vinyl silicone oil and hydrogen-containing silicone oil, stirring for 10-60min at 8000-4000 r/min, stirring for 180-600min at 1500-4000r/min, then adding a cross-linking agent and a catalyst into the silicone rubber, stirring for 10-60min at 1500-4000r/min, vacuum drying, extracting bubbles in the mixture, pouring the mixture into a mold, and obtaining room-temperature vulcanized silicone rubber after 12-36 h; the volume ratio of the addition parts of the vinyl silicone oil to the hydrogen-containing silicone oil is 1: 0.5-5 percent of modified nano silicon carbide, wherein the addition amount of the modified nano silicon carbide is 5-50 percent of vinyl silicone oil by weight, the cross-linking agent is tetramethoxysilane, and the addition amount of the cross-linking agent is 1-20 percent of vinyl silicone oil by weight; the catalyst is dibutyl tin dilaurate, and the addition amount is 0.5-5 wt% of vinyl silicone oil. The room temperature silicone rubber has good dimensional stability, basically generates no internal stress, but has small intermolecular acting force, low tensile strength and poor mechanical property, and the ethyl (carbamyl carbamoyl) carbamate and the hexamethylene diisocyanate can react with silicon hydroxyl in the silicone rubber to form chemical combination with the silicone rubber to form a three-dimensional network structure through crosslinking and curing, so that the condensed silicone rubber is enhanced through the molecular structure and the rigid core, the crosslinking and curing effect of the silicone rubber is improved, and the performance retention rate of the silicone rubber after aging is improved.

In one embodiment of the present invention, in the preparation method of the silicone rubber composite material for the insulated cable, a cross-linking agent, a catalyst and an additive may be added to the vinyl silicone oil and the hydrogen-containing silicone oil together. The additive is ethyl (carbamyl) carbamate and hexamethylene diisocyanate, the addition amount of the ethyl (carbamyl) carbamate is 1-10 wt% of the vinyl silicone oil, and the addition amount of the hexamethylene diisocyanate is 1-5 wt% of the vinyl silicone oil.

Preferably, the addition amount of the modified nano silicon carbide is 5-50 wt% of the vinyl silicone oil.

In one embodiment of the present invention, the ratio of the vinyl silicone oil to the crosslinking agent is 1: 0.01 to 0.12, preferably, the addition ratio of the vinyl silicone oil to the crosslinking agent may be 1: 0.02-0.1, e.g., 1: 0.02, 1: 0.04, 1: 0.06, 1: 0.08, 1: 0.1.

In one embodiment of the present invention, the amount of the modified nano silicon carbide is 5 to 50 wt%, and preferably, the amount of the modified nano silicon carbide may be 10 to 45 wt% of the vinyl silicone oil, for example, 10, 15, 20, 25, 30, 35, 40, 45 wt%.

The invention adopts the modified nano silicon carbide, thereby improving the dielectric property of the silicon rubber added with the nano silicon carbide, and the problems of mechanical property of the silicon rubber and the property retention rate after aging in the using process are improved by adding the ethyl (carbamyl) carbamate and the hexamethylene diisocyanate.

Drawings

FIG. 1 is a particle size distribution diagram of modified nano-silicon carbide;

FIG. 2 is a transmission electron microscope image of modified nano-silicon carbide;

FIG. 3 is a graph showing relative dielectric constants of silicone rubbers obtained in examples and comparative examples;

FIG. 4 is a graph showing dielectric loss factors of silicone rubbers obtained in examples and comparative examples;

FIG. 5 is a graph showing the characteristic breakdown field strengths of silicone rubbers obtained in examples and comparative examples.

Detailed Description

The technical solution of the present invention is further described in detail below with reference to the following detailed description and the accompanying drawings: