1. Aramid paper
Aramid paper (also known as "aramid fiber paper") is made of aramid staple fibers and aramid fibrids as raw materials for papermaking. It is made by diagonal netting and wet forming, and then hot-pressed.
Second, the classification of aramid paper
Aramid paper is divided into meta-aramid paper and para-aramid paper according to different materials.
1. Meta-aramid paper: also known as meta-aramid paper (abbreviated as aramid paper), it is a special kind of pure meta-aramid (polymetaphenylene isophthalamide fiber). Paper has high strength, low deformation, high temperature resistance, chemical corrosion resistance, flame retardant and excellent electrical insulation properties. It is widely used in national defense, aerospace, high-speed trains, electrical insulation and other fields. It is a high-tech related to national security. new material.
2. Para-aramid paper: It is made of para-aramid staple fiber and para-aramid fibrid (aramid pulp) as raw materials, made according to papermaking technology, and then made by hot pressing.
Third, the characteristics of meta-aramid paper
1. Thermal stability
The most important characteristic of aramid paper is long-term thermal stability. It can be used for more than 10 years at 180°C, and its service life is longer than that of industrial organic high temperature resistant paper. When placed under dry heat at 200℃ for 1000h, the mechanical strength still maintains 75% of the original; placed at 120℃ under damp heat for 1000h, the mechanical strength still maintains above 60% of the original; above 370℃, a small amount of CO2, CO and N2 will be decomposed gas.
2. Flame retardant performance
The limiting oxygen index (LOI) value of aramid paper is ≥28. It is a flame-retardant material. It will not burn, melt or produce droplets in the air, but will only start to decompose at extremely high temperatures (>370°C) .
3. Electrical insulation
Aramid paper has excellent electrical insulation properties. Due to the good thermal stability of aramid paper, it still maintains good electrical properties at high temperatures. Aramid paper has a lower relative dielectric constant and dielectric loss factor, which can make the insulation electric field distribution more uniform and the operating dielectric loss is smaller. It is a good environmentally friendly insulation material.
4. Mechanical properties
Aramid paper is a film-like material made of high-strength meta-aramid chopped fibers, with compact structure, smooth surface, good flexibility, and good tensile and tear resistance. With good dimensional stability and high specific strength, it is a non-metallic honeycomb structure raw material with superior performance.
5. Chemical stability
The molecules of aramid paper are linear macromolecules composed of aryl groups connected to each other by amide bridges. In its crystal, hydrogen bonds are arranged in two planes to form a three-dimensional structure of hydrogen bonds. Due to the strong hydrogen bond, it has a stable structure, excellent chemical resistance, can withstand most high-concentration inorganic acids, and is very stable to most other chemical reagents and organic solvents.