High-speed preparation method for producing large-tow carbon fibers

Abstract

The invention provides a high-speed preparation method for producing large-tow carbon fibers, and belongs to the technical field of preparation of large-tow carbon fiber materials. The method comprises the following steps of pre-oxidizing large-tow polyacrylonitrile copolymer fibers in an air atmosphere at the temperature of 220-300 DEG C, and performing heat treatment in an oxidation furnace in asix-gradient temperature rising mode for 45-90 minutes to obtain pre-oxidized filaments of tow carbon fibers, wherein the temperature gradient is 9+ / -3 DEG C, the production speed is 12-15m / min, andthe draw ratio is 0.98-1.20; performing low-temperature carbonization treatment on the pre-oxidized filaments; and performing high-temperature carbonization treatment on the carbon fibers subjected tolow-temperature carbonization treatment to obtain the large-tow carbon fibers. The tensile strength of the prepared carbon fibers is over 5,000 MPa, and the modulus is 240-250 GPa.

Description

technical field [0001] The invention belongs to the technical field of large-tow carbon fiber material preparation, and in particular relates to a high-speed preparation method for producing large-tow carbon fiber. Background technique [0002] Polyacrylonitrile-based carbon fiber reinforced fiber is the main material of composite materials, and high-efficiency and low-cost carbon fiber plays an important role in promoting the lightweight of composite materials. Polyacrylonitrile fiber (precursor) is the main raw material for preparing large-tow carbon fiber; large-tow carbon fiber has the advantage of low cost compared with small-tow fiber, and large-tow carbon fiber is more conducive to the development of low-cost, general-purpose However, in the foreign market, large-scale production of large-tow carbon fiber is mainly carried out by Mitsubishi, Toho, SGL, Aksa, Formosa Plastics, etc. Foreign blockade and domestic large-tow raw silk production and large-tow carbon fiber ...

AI Technical Summary

Problems solved by technology

Polyacrylonitrile fiber (precursor) is the main raw material for preparing large-tow carbon fiber; large-tow carbon fiber has the advantage of low cost compared with small-tow fiber, and large-tow carbon fiber is more conducive to the development of low-cost, general-purpose However, in the foreign market, large-scale production of large-tow carbon fiber is mainly carried out by Mitsubishi, Toho, SGL, Aksa, Formosa Plastics, etc. Foreign blockade and domestic large-tow raw silk production and large-tow carbon fiber carbonization production technology, equipment, environment and other factors restrict the development; domestic large-scale production capacity of large-tow carbon fiber is currently only Jilin Carbon Valley Carbon Fiber Co., Ltd. and Jilin Jinggong Carbon Fiber Co., Ltd. (Jilin Carbon Valley mainly produces large tow carbon fiber precursors, Jilin Jinggong mainly carbonizes), and there are also enterprises that are developing and planning construction, such as Shanghai Petrochemical, Weihai Development, Kangdexin, Xinjiang Carbon Valley New Material Co., Ltd., Zhongfu Shenying Carbon Fiber, etc. Among them, the ZL201610517888.5 developed by Weihai discloses the pre-oxidation method for preparing large-tow carbon fibers. The 24K polyacrylonitrile copolymer fiber is pre-oxidized and heat-treated in an air atmosphere for 60-90 minutes , the circulating wind speed of the oxidation furnace is controlled at 6±2m / s, the carbonization time needs to be 6±1.5min, the tensile strength of the obtained carbon fiber is 4.5-4.7GPa, and the modulus is about 240GPa

[0003] While vigorously developing large tow carbon fibers, the main problems in the production of large tow carbon fibers are as follows: 1. During the pre-oxidation process, the heat released by the oxidation of large tow polyacrylonitrile fibers (precursor filaments) is not easy to dissipate heat, resulting in that the heat cannot be timely Discharge, and then fiber breakage, roll winding, etc. will affect stable production and cause excessive dispersion of fiber indicators; 2. The pre-oxidation of large-tow polyacrylonitrile fibers (precursors) is more difficult, and large-tow polyacrylonitrile fibers With more tows, the inside of the fiber is less likely to be oxidized, resulting in obvious skin-core structure, and low-temperature carbonization is difficult to pass through, etc.

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