TECHNICAL FIELD

The invention relates to a method of conductive fabric carbonization, which allows knitted fabric, which is developed to be utilized in the field of textile, to be made carbon and conductive following various process steps, and which paves the way for using heat efficiently by consuming less energy.

BACKGROUND ART

Acrylonitrile, also called vinyl cyanide, is the nitrile of acrylic acid, an unsaturated carboxylic acid.

Acrylonitrile can be obtained from petroleum distillation products by way of easy and inexpensive methods. Liquid acrylonitrile is polymerized using various catalysts (benzoyl peroxide, potassium persulfate, or a mixture of hydrogen peroxide + ferrous sulfate).

This polymer was first synthesized in 1930 and used as artificial rubber from 1930 to 1945. In 1945, it was first introduced to the market under the name of Fiber in the form of filament. It was then launched to the market in 1950 under the name of Orlon in the form of filament, and in 1952, in the form of staple fiber under the same name.

The reason why such a long time had passed between its synthesis and the production of filaments from this polymer is that it has some negative properties due to the structure of polyacrylonitrile. Polyacrylonitrile degrades at temperatures around its melting point, which is around 200 °C. Therefore, it cannot be turned into filaments through melt spinning. Moreover, it cannot dissolve in common organic solvents because of its structure. That is due to the fact that nitrile groups with negative polarity in the polymer chain form H-bridges with the methylene group hydrogen of another polymer chain. These bonds crosslink the polymer chains. Additionally, van der Waals forces also hold the chains together, increase the crystallization rate of the polymer, and reduce its solubility. For the reasons mentioned herein, many years passed by in search of a suitable solvent that can dissolve the PAN polymer.

Polyacrylonitrile filaments that were initially manufactured consisted of 100% pure polymer. Their tacticity and crystallization rates are quite high due to their above- mentioned structural properties. Therefore, their dyeability and moisture absorption were unfavorable, and they were difficult to dye. Currently, 100% PAN is not employed in the production of polyacrylonitrile fiber. Instead, in an attempt to improve their properties and impart dyeability, acrylonitrile copolymers containing another monomer up to 15% are synthesized and are utilized to manufacture fibers. If polar groups are present in the structure of the comonomer, which is added to the polymer, then the polymer chain gains polarity. Concurrently, the rate of crystalline regions in the structure decreases. The solubility of the polymer in some solvents and its dyeability thus increase. Fibers made of polyacrylonitrile containing up to 15% comonomer in its structure are called acrylic fibers. Acrylic fibers gain either anionic or cationic character depending upon the polarity properties of the relevant added comonomer. The addition of components such as vinyl pyridine and acrylamide as comonomers to the polyacrylonitrile chain gives the compound a cationic character in acidic environments.

Polyacrylonitrile polymers do not melt when heated to the temperatures required for the melt spinning method and are not suitable for fiber production with the said method since changes occur in their chemical structure at temperatures around 320°C. However, polyacrylonitrile (PAN) polymers can be dissolved in suitable solvents and turned into a polymer solution with a viscosity that enables fiber spinning. Acrylic fibers are, therefore, produced by way of the solution spinning method. Solution spinning includes two methods as wet spinning and dry spinning.

Described in publication no. US2015353697A9 titled “Prepreg and carbon fiber reinforced composite materials” in the prior art, the invention is summarized as follows: “The present invention relates to a prepreg and carbon fiber reinforced composite material having an excellent impact resistance and conductivity together.”

Described in publication no. CN106917156A titled “Preparation method of boron- containing polyacrylonitrile filament and its carbon fiber and graphite fiber” in the prior art, the invention is summarized as follows: “The invention provides a preparation method for a boron-containing polyacrylonitrile filament and its carbon fiber and graphite fiber. The method comprises the following steps: firstly, dispersing nano boride in a solvent, then adding acrylonitrile, a copolymer monomer and an initiator, and preparing a nano boride/polyacrylonitrile mixture solution by an in-situ solution polymerization process; then adopting a wet spinning process, and preparing a continuous-length nano boride/polyacrylonitrile composite filament from the nano boride/polyacrylonitrile mixture solution; and finally, adopting a continuous process, and successively carrying out pre-oxidation, carbonization and graphitization processes, and obtaining the carbon fiber evenly containing boron and the graphite fiber. The method can realize uniform distribution of boron in the carbon fiber, gives full play to the catalytic graphitization effect of boron, lowers a graphitization temperature, improves the graphitization degree, also can be applied in a continuous graphitization process, significantly improves the graphite fiber preparation efficiency, and greatly reduces the cost of preparation of the graphite fiber.”

Described in publication no. JP2005273037A titled “Method for producing carbon fiber” in the prior art, the invention is summarized as follows: “PROBLEM TO BE SOLVED: To provide ultra fine carbon fibers which do not have a branched structure, have a high strength/a high elastic modulus, and have a fiber diameter of 0.001 pm to 2pm.

SOLUTION: A method for producing the carbon fibers comprises a process for forming precursor fibers from a mixture comprising a thermoplastic carbon precursor and a thermoplastic resin having an oxygen diffusion coefficient of 9.0x10. At 30°C, a process for subjecting the precursor fibers to a stabilization treatment to stabilize the thermoplastic carbon precursor in the precursor fibers to form the stabilized precursor fibers, a process for removing the thermoplastic resin from the stabilized precursor fibers to form the fibrous carbon precursors, and a process for carbonizing or graphitizing the fibrous carbon precursors.”

In conclusion, the abovementioned shortcomings and the inadequacy of the current practice entail an improvement in the respective technical field. Thus, there is a need for an invention to overcome the described problems.

DESCRIPTION OF THE INVENTION

Developed for eliminating the aforementioned disadvantages and providing new advantages to the respective technical field, the present invention relates to a method of conductive fabric carbonization, which allows knitted fabric, which is developed to be utilized in the field of textile, to be made carbon and conductive following various process steps, and which paves the way for using heat efficiently by consuming less energy.

An objective of the present invention is to obtain a durable fabric with a low total gas amount, which is enriched through various stages by consuming less energy.

The present disclosure describes a fabric that is not identical to those manufactured by other carbon factories. The relevant factories generally produce yams and cannot manufacture the concerned material in the form of fabric. In this invention, however, knitted fabric is made carbon and conductive through scouring. By using heat efficiently, the inventors ensure consuming of less energy while utilizing each metal or element in the process, as the fabric has a wide surface area. In other words, heat is used efficiently in connection with lower energy consumption as a result of the fact that the surface of the fabric is wider than a yarn.

Another objective of the present invention is to enrich the fabric with the materials to be indicated in the detailed description.

Drawings The embodiments of the present invention, briefly summarized above and discussed in more detail below, can be understood by referring to the exemplary embodiments of the invention described in the accompanying drawings. However, it should be noted that the accompanying drawings illustrate only the typical embodiments of the present invention and therefore are not deemed to limit its scope as it may allow other equally effective applications.

Figure-1 : It is the schematic view of the fabric enrichment method of the invention.

For the sake of clarity, identical reference numbers are used wherever possible, to indicate identical elements common to the figures. The figures are not drawn to scale and can be simplified for clarity. It is contemplated that the elements and features of an application can be usefully incorporated into other applications without the need for further explanation.

DETAILED EXPLANATION OF THE INVENTION

This detailed description of method of conductive fabric carbonization of the present disclosure is only intended for providing a better understanding of the subject matter and should not be construed in any restrictive sense.

As illustrated in Figure 1 , polymeric fiber, orlon, and cotton polyester are woven on knitting machines at a measurement of 1.3 x 100 meters. The woven fabric is fed into the mechanism to be stretched with steam at 90-190 °C. Then, the steam- stretched fabric is dried in hot air at 180-300 °C to get rid of water vapor. 100 meters of fabric is dried in 30 minutes. Before moving onto the next step in the second oven, graphene is given to the fabric with a voltage of 12 V in a pool of electrolysis.

In the next step with the second oven, the fabric is treated with enriched gases in two stages described hereinbelow for carbonization purposes.

In the 1 ^st stage, nitrogen (N2) is heated at 300-1200 °C. In the 2 ^nd stage, the fabric is carbonized at 1000-1600 °C under argon. 100 meters of fabric is treated in an hour.

Next is the graphitization step. At this stage, the fabric is graphitized at 1500-2800 °C with nitrogen (N2), which is heavier than air. The reason behind the use of nitrogen is to prevent the fabric from burning. After the application of nitrogen, the fabric is electrolysed in the pool of acid. In the pool of electrolysis, the fabric is impregnated with sodium hydrochloride and nitric acid. At this stage, the fabric is enriched. The metal(s) desired to be adhered to the fabric are joined thereto with epoxy resin. At this step, elements such as tungsten, nickel, silver, boron, copper are joined. Then, the impregnated elements are compressed to the fabric using a press machine to ensure they adhere well. After pressing, the fabric is dried in ovens under ultraviolet light at 200 °C. Upon completion of drying, the fabric is ready and rolled up.

In this method, primary materials employed for the fabric of this invention are polymeric fiber, orlon, cotton polyester, graphite powder, sodium hydrochloride, nitric acid, nitrogen, argon, epoxy resin. Elements joined onto the fabric in the enrichment stage consist of tungsten powder, nickel powder, silver powder, boron powder, coconut carbon, iron oxide, and aluminum powder. At least one or more of these elements can be used within the scope of this method.

In the present invention, yarn and orlon are not scoured. A 130-cm wide fabric knitted from cotton polyester and orlon is processed. Graphite is added to the aluminum sulfate solution in the first pool of electrolysis after about 300 °C. Upon reaching 300 °C, the first pool of electrolysis is achieved. Upon reaching 2500 °C, tungsten, nickel, and silver are added to the second pool. At the end of the production line, tungsten, silver, nickel, boron powder, and coconut carbon are added into the cylinder again, and then it is compressed onto the fabric with epoxybased resin poured from the cylinder. At the last stage, the fabric is fed with boron, borax, nickel, walnut carbon, bone dust, and some metal powders in the pools of electrolysis, because the product is not a yam but a fabric; in other words, it has a larger surface area that allows the addition of materials to the desired extent. Since a narrow yam is not produced in the method of the invention, the fabric can be supplemented with other additives. This is the fundamental aspect distinguishing the present invention from those of other carbon producers. In this way, PAN orlon fiber coal tar and cotton are converted into carbon fiber.