阅读说明：本技术 一种可固化的绝缘乙烯基硅脂材料及其制备方法与用途 (Curable insulating vinyl silicone grease material and preparation method and application thereof ) 是由 周凯 陈熠东 任显诚 李泽瑞 陈诗佳 于 2019-09-03 设计创作，主要内容包括：本发明公开了一种可固化的绝缘乙烯基硅脂材料及其制备方法与用途,该可固化的绝缘乙烯基硅脂材料由以下原料乙烯基硅油、二氧化硅、侧含氢硅油、端含氢硅油、抑制剂、催化剂按质量比100：(5～50)：(0.1～20)：(0.1～20)：(0.01～1)：(0.005～1)固化而成。该可固化的绝缘乙烯基硅脂材料为加成型聚有机硅氧烷,具有优良的润滑性和防水性,可以作为电缆附件与电力电缆之间的界面涂料；由于该可固化的绝缘乙烯基硅脂材料具有优异的电气性能和适当的固化前粘度,能够在涂覆在电缆附件与电力电缆之间后继续固化,从而提升界面击穿强度、防水性能等。此外,由于固化不产生小分子副产物,从而避免体积收缩和产生气泡,因此不会溶胀硅橡胶,能够延长电缆附件的使用寿命,因此具有较强的实用性。(The invention discloses a curable insulating vinyl silicone grease material and a preparation method and application thereof, wherein the curable insulating vinyl silicone grease material is prepared from the following raw materials of vinyl silicone oil, silicon dioxide, lateral hydrogen-containing silicone oil, terminal hydrogen-containing silicone oil, an inhibitor and a catalyst in a mass ratio of 100: (5-50): (0.1-20): (0.1-20): (0.01-1): (0.005-1) curing. The curable insulating vinyl silicone grease material is addition type polyorganosiloxane, has excellent lubricity and water resistance, and can be used as an interface coating between a cable accessory and a power cable; the curable insulating vinyl silicone grease material has excellent electrical properties and proper viscosity before curing, and can be continuously cured after being coated between a cable accessory and a power cable, so that the interface breakdown strength, the waterproof property and the like are improved. In addition, because the curing does not generate micromolecular byproducts, the volume shrinkage and the generation of bubbles are avoided, the silicone rubber is not swelled, the service life of the cable accessory can be prolonged, and the practicability is high.)

1. The curable insulating vinyl silicone grease material is characterized by comprising the following raw materials of vinyl silicone oil, silicon dioxide, lateral hydrogen-containing silicone oil, terminal hydrogen-containing silicone oil, an inhibitor and a catalyst according to the mass ratio of 100: (5-50): (0.1-20): (0.1-20): (0.01-1): (0.005-1) curing.

2. The curable insulating vinyl silicone grease material according to claim 1 wherein the vinyl silicone oil is α, ω -divinylpolydimethyl siloxane.

3. The curable insulating vinyl silicone grease material according to claim 2, wherein said vinyl silicone oil is α, ω -divinylpolydimethyl siloxane having a viscosity of 500 to 10000 CS.

4. The curable insulating vinyl silicone grease material according to claim 1, wherein the lateral hydrogen-containing silicone oil is polydimethylsiloxane having a hydrosilicon functional group at both ends and in a side chain.

5. The curable insulating vinyl silicone grease material according to claim 4, wherein the side hydrogen-containing silicone oil is a side hydrogen-containing polysiloxane having a viscosity of 25 to 500CS and a terminal hydrogen content of 0.02% to 2%.

6. The curable insulating vinyl silicone grease material according to claim 1, wherein said terminal hydrogen-containing silicone oil is a polysiloxane having a hydrosilicon functional group at both terminals.

7. The curable insulating vinyl silicone grease material according to claim 6, wherein the terminal hydrogen-containing silicone oil is a terminal hydrogen-containing polysiloxane having a viscosity of 25 to 500CS and a terminal hydrogen content of 0.02% to 2%.

8. The curable insulating vinyl silicone grease material according to claim 1, characterized in that the inhibitor is a room temperature inhibitor or/and a temperature rise inhibitor; the catalyst is a platinum catalyst.

9. The process for producing a curable insulating vinyl silicone grease material according to any one of claims 1 to 8, characterized by comprising the steps of:

(1) uniformly mixing vinyl silicone oil and silicon dioxide and defoaming to prepare a mixture A;

(2) uniformly mixing the mixture A with lateral hydrogen-containing silicone oil, terminal hydrogen-containing silicone oil and an inhibitor, then adding a catalyst, and defoaming to obtain a mixture B;

(3) and standing and curing the obtained mixture B to obtain the cured insulating vinyl silicone grease material.

10. Use of the curable insulating vinyl silicone grease material according to any one of claims 1 to 8 as an interface coating between a cable accessory and a power cable.

Technical Field

The invention belongs to the technical field of power cables, and relates to a curable vinyl silicone grease material used in the field of power cables, and application of the material in the aspect of interface coating between a power cable and a cable accessory.

Background

More and more power cables are laid underground, so that the urban aesthetic feeling is improved, and the space is effectively utilized. However, there are many problems in laying underground power cables, such as water tree and electricity tree failures in the cable body, water inflow due to loose connection at the cable accessory position, breakdown, and the like. Among the overall cable faults, cable accessory faults account for a significant percentage, up to about 70% of the overall cable line faults. It follows that the cable accessory is more prone to failure than the cable body.

The cable accessories are the middle connection part of a cable in a power system or the terminal connection of the cable and are divided into two types of thermal shrinkage and cold shrinkage, wherein the cold shrinkage cable accessories are wide in application and convenient to use and have the tendency of gradually replacing the thermal shrinkage. The cold-contraction cable accessory is generally made of silicon rubber or ethylene propylene rubber, wherein the silicon rubber cold-contraction cable accessory is an integral prefabricated connector which is expanded in advance and provided with a spiral supporting pipe in the middle. When the cable is installed on site, the pre-expansion piece is sleeved at the tail end or joint of the treated cable, and the plastic spiral strip supported inside is pulled out, so that the tail end or the joint of the cable is compressed. And the silicone rubber cold-shrink cable accessory and the cable can be coated with silicone rubber to fill the gap between the silicone rubber cold-shrink cable accessory and the cable so as to prevent air from entering. However, since the interface between the cable and the cable accessory is more susceptible to various environmental factors such as temperature difference and humidity, and the silicone grease is a secondary processed product of silicone oil and a thickener such as white carbon black, the silicone oil gradually swells the silicone rubber, so that the grip strength is reduced and air gaps are generated at the interface, and thus, water vapor gradually permeates into the interface, so that the interface is also a weak part of frequent faults of the power system.

The conventional silicone grease is replaced by fluorinated silicone grease, but the fluorinated silicone grease is also a composition of small molecular substances, and the problem of swelling cannot be fundamentally solved. In addition, the interface between the cable accessory and the cable is required to have good electrical properties, which not only requires that the coating material between the cable accessory and the cable is not easily volatilized, does not swell silicone rubber or crosslinked polyethylene, but also requires that some polar adhesive substance cannot be added, and has good stability in use under external field conditions.

If the silicone gel material is used alone, the performance of the silicone grease cannot be achieved, because the common silicone gel is easy to flow before curing, and is lost from the defect. At present, the silicon gel material which can meet the requirements of the use in the insulation field, has thixotropy before curing and low dielectric constant and has high resistivity is not reported.

Therefore, a novel curable silicone grease-like material which can be used between a cable accessory and a cable is developed, the problems of swelling of the silicone grease material and poor thixotropy of the silicone gel material are solved, and the curable silicone grease-like material has important practical value for the continuous and stable development of the power cable.

Disclosure of Invention

The present invention is directed to solve the above problems in the prior art, and an object of the present invention is to provide a curable insulating vinyl silicone grease material and a method for preparing the same, wherein the prepared curable insulating vinyl silicone grease material has good electrical properties and a suitable viscosity before curing, and does not introduce air bubbles during curing to affect the electrical properties of silicone gel.

Another object of the present invention is to provide the use of the above curable insulating vinyl silicone grease material for the interface coating of cable accessories with power cables.

The invention provides a curable insulating vinyl silicone grease material, which is prepared from the following raw materials of vinyl silicone oil, silicon dioxide, lateral hydrogen-containing silicone oil, terminal hydrogen-containing silicone oil, an inhibitor and a catalyst in a mass ratio of 100: (5-50): (0.1-20): (0.1-20): (0.01-1): (0.005-1) curing. The preferable range of the mixture ratio of the raw materials is as follows: the mass ratio of the vinyl silicone oil, the silicon dioxide, the lateral hydrogen-containing silicone oil, the terminal hydrogen-containing silicone oil, the inhibitor and the catalyst is 100: (10-40): (0.5-10): (0.5-10): (0.01-1): (0.005-1).

In the curable insulating vinyl silicone grease material, the vinyl silicone oil in the raw materials is alpha, omega-divinyl polydimethylsiloxane, such as alpha, omega-divinyl polydimethylsiloxane with the viscosity of 500-10000 CS; in order to facilitate defoaming, the vinyl silicone oil is preferably 500-1000 CS alpha, omega-divinyl polydimethylsiloxane.

The silicon dioxide in the raw materials of the curable insulating vinyl silicone grease material is one or a mixture of more of Woguangsai hydrophobic white carbon black, Kabot gas phase method white carbon black and Germany Wake gas phase method white carbon black. The white carbon black used should be suitable for use in silicone gel systems, not affect curing, and have low dielectric constant, high volume resistivity, thickening properties, dispersibility, hydrophobicity and high specific surface area. An appropriate amount of silica is effective in adjusting the viscosity of the insulating vinyl-silicon adhesive material before curing, however, too much silica not only introduces too many bubbles, but also causes agglomeration and increases the manufacturing cost.

In the curable insulating vinyl silicone grease material, the lateral hydrogen-containing silicone oil in the raw material is polysiloxane of which both ends and lateral chains contain silicon hydrogen functional groups, such as lateral hydrogen-containing polysiloxane with viscosity of 25-500 CS and terminal hydrogen content of 0.02-2%; the higher the viscosity, the better the degree of crosslinking, so the side hydrogenous silicone oil is preferably side hydrogenous polysiloxane of 60-150 CS.

In the curable insulating vinyl silicone grease material, the terminal hydrogen-containing silicone oil in the raw material is polysiloxane only containing silicon hydrogen functional groups at two ends, such as terminal hydrogen-containing polysiloxane with the viscosity of 25-500 CS and the terminal hydrogen content of 0.02-2%. Here the terminal hydrogenpolysiloxane functions as a chain extender.

In the curable insulating vinyl silicone grease material, the inhibitor in the raw materials is a room temperature inhibitor or/and a temperature rise inhibitor, and can be added according to curing requirements. The inhibitor may be at least one of 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 1-ethynylcyclohexanol, 3-phenyl-1-butyn-3-ol, and the like.

The catalyst in the raw materials of the curable insulating vinyl silicone grease material is a platinum catalyst which can be one or a mixture of more of platinum black, platinum chloride and a platinum metal mesh. The platinum catalyst can catalyze the components of the silica gel to perform addition reaction, and meanwhile, small molecule gas is not generated.

The curable insulating vinyl silicone grease material provided by the invention is cured by adopting the raw materials and based on the curing reaction of the following chemical reaction formula.

The preparation method of the curable insulating vinyl silicone grease material specifically comprises the following steps:

(1) uniformly mixing vinyl silicone oil and silicon dioxide and defoaming to prepare a mixture A;

(2) uniformly mixing the mixture A with lateral hydrogen-containing silicone oil, terminal hydrogen-containing silicone oil and an inhibitor, then adding a catalyst, and defoaming to obtain a mixture B;

(3) and standing and curing the obtained mixture B to obtain the curable insulating vinyl silicone grease material.

The preparation method of the curable insulating vinyl silicone grease material takes vinyl silicone oil as a siloxane raw material, takes silicon dioxide as a thixotropic agent, takes lateral hydrogen-containing silicone oil as a cross-linking agent, takes terminal hydrogen-containing silicone oil as a chain extender, and cures under the catalysis of a catalyst to form high-molecular polyorganosiloxane, and the inhibitor can be used for delaying the curing time. The addition type polyorganosiloxane gel does not generate small molecular substances during crosslinking and vulcanization, and volume shrinkage and air holes are avoided, so that the shrinkage rate is low. In addition, the product has good vulcanization performance at the deep position, and has better sealing performance than a condensation type product under the high-temperature condition. The invention firstly uniformly mixes the vinyl silicone oil and the silicon dioxide with relatively low density and large volume and defoams the mixture, and then adds other raw materials to uniformly mix and defoam the mixture.

The preparation method of the curable insulating vinyl silicone grease material adopts a vacuum defoaming technology in the defoaming operation in the step (1) and the step (2).

In the above method for preparing the curable insulating vinyl silicone grease material, the curing time of the mixture B in the step (3) can be adjusted by adjusting the content and kind of the inhibitor, so as to achieve the fixed bonding between the actual cable accessory and the power cable.

The curable insulating vinyl silicone grease material prepared by the method is addition type polyorganosiloxane which has lower crosslinking density than silicone rubber, larger deformability and self-repair of body cracks, has good electrical performance and proper viscosity before curing, has certain adhesive force with silicone rubber, and has the capability of filling interface defects equivalent to silicone grease.

The curable insulating vinyl silicone grease material provided by the invention can be used as an interface coating between a cable accessory and a power cable to bond the silicone rubber cold-shrink cable accessory and the crosslinked polyethylene and fill an air gap in the silicone rubber cold-shrink cable accessory and the crosslinked polyethylene. The curable insulating vinyl silicone grease material not only can provide lubricity and defect filling capacity equivalent to those of silicone grease, but also can be cured continuously, so that the interface breakdown strength and the water resistance are improved, and the curable insulating vinyl silicone grease material has the advantages of convenience in curing and no need of changing a construction mode. The curable insulating vinyl silicone grease material provided by the invention also has good electrical properties and proper viscosity before curing, and cannot bring bubbles to cause reduction of insulating properties; in addition, since the curable insulating vinyl silicone grease material does not swell silicone rubber, it has a long-term use performance superior to that of silicone grease.

Compared with the prior art, the invention has the following beneficial effects:

1. the curable insulating vinyl silicone grease material provided by the invention is addition type polyorganosiloxane, has excellent lubricity and waterproofness, and can be used as an interface coating between a cable accessory and a power cable; the curable insulating vinyl silicone grease material has excellent electrical properties and proper viscosity before curing, and can be continuously cured after being coated between a cable accessory and a power cable, so that the interface breakdown strength, the waterproof property and the like are improved.

2. The curable insulating vinyl silicone grease material provided by the invention is a paste with a certain viscosity before curing, and does not generate small molecule by-products during curing, so that bubbles are not brought in to cause the reduction of the insulating property of power cables and cable accessories.

3. In the preparation process of the curable insulating vinyl silicone grease material, micromolecular by-products are not generated during curing, so that volume shrinkage and bubble generation are avoided, silicone rubber is not swelled, the service life of cable accessories can be prolonged, and the curable insulating vinyl silicone grease material has high practicability.

4. In the preparation process of the curable insulating vinyl silicone grease material, the curing time and conditions are controllable, so that a candidate interface coating with low cost, quick response and excellent electrical property is provided for the development of power cables.

5. In the preparation process of the curable insulating vinyl silicone grease material, curing conditions such as the crosslinking degree, thixotropy before curing, curing time and the like of silicone gel can be adjusted by adjusting the components and the proportion of raw materials, so that the silicone gel coating with excellent insulating property and good construction performance is obtained, and the curable insulating vinyl silicone grease material has stronger practicability.

Drawings

Fig. 1 shows the results of breakdown test of silicone grease and curable insulating vinyl silicone grease materials in their initial state.

FIG. 2 shows the results of breakdown testing of silicone grease and curable insulating vinyl silicone grease materials in the aged state.

Detailed Description

The present invention is described in detail below by way of examples, it should be noted that the examples are only for illustrating the present invention, but not for limiting the scope of the present invention, and those skilled in the art can make some non-essential modifications and adaptations of the present invention based on the above-mentioned disclosure.

The breakdown experiments adopted in the following comparative examples and examples are a method for performing breakdown voltage resistance test on voltages applied to two ends of a material by adopting an oil-immersed step-by-step voltage boosting method according to GB/T29310-2012 design, and breakdown data obtained by Weibull distribution analysis.

The aging operations referred to in the following comparative examples and examples were: placing the mixture into an oven, and aging the mixture for 72 hours at constant temperature and humidity at the temperature of 100 ℃.

The following comparative examples and examples were investigated for electrical properties of the curable insulating vinyl silicone grease material and silicone grease prepared using crosslinked polyethylene and silicone rubber as the subjects of investigation. Firstly, the crosslinked polyethylene and the silicon rubber are respectively made into small pieces with the same size of 2.5cm multiplied by 5cm multiplied by 3mm, and the interface is polished.

Comparative example 1

The interface of 5cm x 3mm of the cross-linked polyethylene and the silicone rubber was uniformly coated with silicone grease, and the initial and aged interface breakdown experiments were performed. And testing the viscosity of the silicone grease by using a laminar viscometer, testing the dielectric constant and the volume resistivity of the silicone grease by using a broadband dielectric resistance spectrometer, and finally testing the oil leakage value of the silicone grease by using a mode of absorbing residual liquid by using filter paper.

Comparative example 2

The crosslinked polyethylene and silicone rubber were bonded without any coating at the 5cm x 3mm interface and subjected to interfacial breakdown tests before and after aging.