Aramid fiber/polyimide fiber composite insulation paper with excellent breakdown resistance and preparation method thereof

Abstract

The invention discloses aramid fiber / polyimide fiber composite insulation paper with excellent breakdown resistance. The preparation method comprises the following steps: performing surface oxidation heat treatment on aluminum nitride, thereby enhancing the hydration resistance; performing protonation pretreatment on polyimide chopped fibers, performing pulping, putting a mixture of the polyimide short fiber pulp and chopped aramid fibers into a fiber fluffer, performing fluffing treatment, adding the aluminum nitride suspension, performing mixing, making base paper on a paper sheet former, and performing isothermal boosting hot pressing treatment to obtain the composite insulation paper. The aluminum nitride powder is subjected to heat treatment in an oxidizing atmosphere, so that a compact Al2O3 film is formed on the surface, thereby effectively preventing the hydrolysis reaction of the aluminum nitride; the aluminum nitride powder is mixed with the mixed fiber pulp, so that the small-size aluminum nitride powder is uniformly dispersed in the insulation paper, thereby filling up abundant gaps in the fiber paper structure; and interface traps are formed between the nanoparticles and fibers, thereby implementing effective binding on charges, and enhancing the breakdown strength of the insulation paper.

Description

technical field [0001] The invention relates to the field of polyimide materials, in particular to an aramid fiber / polyimide fiber composite insulating paper with excellent breakdown resistance and a preparation method thereof. Background technique [0002] Insulating paper is widely used as insulating material for equipment such as motors, cables, capacitors and transformers, and is also the main component material of insulating materials such as laminated products, composite materials and prepreg materials. Due to the special use of insulating paper, it is required to have some characteristics different from other paper types, mainly including mechanical properties, electrical properties and thermal stability. [0003] Insulating paper is the main part of the transformer's internal insulation. During long-term operation, it will age due to the combined effects of electric field, temperature, moisture and other factors, causing the insulation performance of the transformer ...

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Problems solved by technology

[0005] However, the surface of aluminum nitride powder is extremely active, and it is easy to undergo hydrolysis reaction with water vapor in the air in a humid environment. An aluminum oxide layer is formed on the surface of aluminum nitride powder, and a large amount of oxygen is dissolved in the aluminum nitride lattice, reducing its Thermal conductivity brings great difficulties to the storage, transportation and subsequent process of aluminum nitride