Method for production of carbonized cloth, and carbonized cloth produced by the method

Abstract

This method for producing the carbonized fabric includes thermally carbonizing a woven fabric, a knitted fabric or a woven and knitted fabric composed of cellulosic fiber yarns as a raw material fiber fabric. The method includes restraining and holding the dried raw material fiber fabric having a water content of less than 25% from one of the longitudinal and transverse directions of the fabric, and then heating the fabric in the restrained and held state in a temperature range of 250-450[deg.]C at a temperature-rising rate of 50-200[deg.]C / hr in an oxidizing atmosphere having an oxygen fractional pressure of 50 mmHg or greater in a heating oven, continuously heating the fabric at a temperature-rising rate of 50-200[deg.]C / hr to a final heating temperature range of 750-1,000[deg.]C in a non-oxidizing atmosphere having an oxygen fractional pressure of less than 50 mmHg, and then heating the fabric at the final heating temperature for a prescribed time. Accordingly, the invention provides a method for producing a carbonized fabric, by which the carbonized fabric having excellent electromagnetic wave absorbability, electric characteristics or dielectric characteristics, heat resistance, mechanical strength, flexibility and the like, can relatively easily and economically be produced.

Description

technical field [0001] The present invention relates to a method for producing carbonized cloth and a carbonized cloth produced therefrom. In detail, the present invention relates to a method for economically producing carbonized cloth with good yields by using cellulose-based fiber cloth as a raw material. The carbonized cloth is excellent in mechanical strength, flexibility, chemical resistance, and washing resistance. It is easy to handle and can be used in various applications due to its excellent electromagnetic wave absorbing ability, electrical properties, dielectric properties, heat resistance, and odor absorbing properties. Background technique [0002] Since carbon fiber has a higher specific modulus and specific strength than other fibers, and is also chemically and thermally stable, it has been widely used as a raw material for various structural composite materials. In addition, its electrical characteristics, shock absorption, X It is also widely used as a raw...

AI Technical Summary

Problems solved by technology

Pitch-based carbon fibers generally have higher elastic modulus, thermal conductivity and electrical conductivity than PAN-based carbon fibers, and are also advantageous in terms of raw material cost, but pitch-based fibers have the following disadvantages: their strength is reflected in the carbonization process, and in the In the state of pitch fiber and non-melting fiber, the mechanical strength is very weak and the carbon fiber is very brittle, so it is difficult to handle in the manufacturing process, and a difficult technology is required, so the manufacturing cost increases.

Therefore, although it is desirable to process these carbon fibers into cloth or sheet form, as mentioned above, it is difficult to perform spinning and weaving processing like ordinary fibers due to their low elongation at break and resistance to bending. , but the carbon fiber is paralleled in one direction, impregnated with various resins, and processed into a prepreg form with a stabilized structure

The prepreg obtained in this way has a relatively simple structure and a high density. In addition, it has the disadvantages of low conformability to curved surfaces during molding, or tends to cause tow disorder during curved surface molding.

In addition, due to the influence of the impregnated resin, the following problems arise: the various performances of carbon fiber are reduced, for example, when it is made into a composite structural material, the adhesion with the matrix is ​​reduced, the electrical conductivity and thermal conductivity are reduced, and harmful substances are generated during combustion, etc.

[0020] However, the method of carbonizing the raw material fiber cloth shown in Patent Document 8 takes a very long time and is inefficient, and similarly to the techniques shown in Patent Documents 1 and 2, the characteristics of the obtained carbonized fiber cloth are also deteriorated. insufficient

In addition, since a strong pressing force is often applied to the entire surface of the raw material cloth during production, it cannot ideally follow the shrinkage of the cloth during carbonization, and may cause partial damage to the cloth, etc.

In addition, the method shown in Patent Document 7, which performs the pretreatment of impregnating the silicon compound as described above, is expected to improve the mechanical strength, but it does not reach a satisfactory level in terms of the flexibility of the fibers, and because the carbonized fibers remain Contains silicon, so there are problems from the thermal, electrical or chemical properties of the fibers

In addition, using the continuous furnace method, the manufacturing equipment becomes very large, and heating is performed in a predetermined temperature rise pattern. In a certain temperature range, several conveying rollers, turning rollers, etc. are arranged, and it is necessary to hang the raw material cloth between them. The traction operation is carried out on the basis of time, and the elongation at break is very small during carbonization. In order to make the cloth that is not resistant to bending pass through the furnace continuously, very delicate tension adjustment is required, so the operation is difficult, and once the cloth breaks, the Operation must be completely interrupted, so inefficiency and poor manufacturing yield

[0021] As mentioned above, conventionally, the production efficiency of carbonized fiber cloth made of cellulose-based fibers is low, and even as the obtained carbonized fiber cloth, cloth with sufficient characteristics cannot be obtained.

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