A kind of low-viscosity heat-conducting epoxy pouring glue and preparation method thereof

Abstract

The invention discloses low-viscosity heat-conducting casting rubber and a preparation method thereof, and belongs to the field of insulating materials. The casting rubber comprises the following components: 100 parts of epoxy resin A, 80-120 parts of an anhydride curing agent B, and 200-480 parts of inorganic heat-conducting powder C, wherein the component C is formed by mixing of spherical inorganic powder and non-spherical inorganic powder; the particle size of the spherical inorganic powder is 4-10 microns; the particle size of the non-spherical inorganic powder is 25-40 microns; and the weight ratio of the spherical powder to the non-spherical powder is (2.5-10) to 10. The preparation method of the casting rubber comprises the following steps: mixing the epoxy resin A with the anhydride curing agent B at the ratio; adding C to a mixture of A and B, mixing, and then defoaming; and casting and solidifying. The viscosity of the casting rubber is effectively lowered through compounding of the spherical powder and non-spherical powder of the component C and control of particle sizes; casting is facilitated; meanwhile, the thermal conductivity and the impact strength are obviously improved; the anti-sedimentation effect is good; and the casting rubber is free of a solvent in preparation and is free of environmental pollution.

Description

technical field [0001] The invention relates to the technical field of insulating materials, in particular to a low-viscosity heat-conducting epoxy casting glue and a preparation method thereof. Background technique [0002] Epoxy castables are one of the key materials required for the manufacture of transformers and reactors for power transmission and transformation equipment. The long-term operation of transformers and reactors leads to temperature rise, and the heat loss caused by dielectric loss under the action of electric field is easy to cause thermal breakdown of epoxy cast insulators. In order to quickly dissipate the heat generated during the operation of power transmission and transformation equipment, ensure the safety of products, and improve the service life, the insulation material industry is paying more and more attention to the insulation structure of power transmission and transformation equipment and the thermal conductivity of insulation materials. [0...

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Problems solved by technology

The existing problems are: (1) due to the addition of a large amount of inorganic powder, the movement between the polymers of the system is hindered, the viscosity of the system becomes very large, the operation is difficult, and it is not easy to pour; (2) due to the high viscosity, vacuum defoaming The bubbles in the process cannot be fully discharged from the system, and there are many defects in the cured system, resulting in a greatly reduced impact performance; (3) Due to the large size of the insulator of the power transmission and transformation equipment, the powder in the system during the curing process settles due to the action of gravity , leading to a large difference in the powder content of the upper and lower parts of the cured insulator, which affects the product quality of power transmission and transformation equipment

However, due to the regular shape of spherical powder particles, compared with non-spherical powder particles, it is not easy to form effective heat conduction channels in the system, so that the thermal conductivity of the cured insulator is not high; at the same time, due to the low viscosity, the curing process settles Faster, the problem of inconsistent powder content on the upper and lower sides of the insulator is more prominent

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