Background Art This invention refers to the fabrication method of conductive PAN fiber by dissolving conductive polymers, sulfonated polyaniline (SPAN) and polyacrylonitrile (PAN) in dimethylsulfoxide (DMSO)-base solution, N, N- dimethylformamide (DMF)-base solution, or aqueous NaSCN- base solution. The conventional preparation process of PAN fiber is classified into three.

- DMSO process : PAN fabrication by spinning solution using DMSO solvent - DMF process : PAN fabrication by spinning solution using DMF solvent - NaSCN process: PAN fabrication by spinning solution using NaSCN aqueous solution PAN fibers'prepared by these three conventional processes produce static electricity, which is a serious weakness. The

method to eliminate static electricity has been studied.

However, the effective method has not been invented yet.

Disclosure of invention In this invention, the spinning solution was prepared by blending conducting polymers (SPAN and PAN) to eliminate the static electricity of pure PAN fiber. Generally, conducting polymer is not dissolved enough in the solvents of DMSO, DMF, or NaSCN aqueous solution which is used in preparation of PAN fiber. In this invention, various novel solvents for fabrication were prepared by adding small amount of water and base into these three kinds of conventional solvents (DMSO, DMF and NaSCN aqueous solution), respectively, in order to enhance solubility. The conductive PAN spinning solution was made by dissolving a conducting polymer, SPAN, in basic solvent. This spinning solution is well mixed homogeneous one, in which the phase separation of two materials, SPAN and PAN does not occur after they were mixed. Thus, breaking of fibers hardly happen when it is spun.

Acidic solution such as hydrochloric acid solution is much better than pure water as a coagulation bath. When SPAN dissolved in basic solution reacts with acidic solution, it is converted into a salt which is insoluble in coagulation bath. In addition, the electrical conductivity is increased more than

1000 times as large as that. Using hydrochloric acid solution as a coagulation bath can simplify washing process because HC1 is evaporated well during drying process following elongation process in hot water.

The fiber and film produced through the whole process show various electrical conductivity of 1X10-9 S/cm ~ 10 S/cm depending on the amount of SPAN.

Brief Description of Drawings Figure 1 is the SEM photograph of pure PAN spun fiber by conventional process. It shows fibrils on the fiber surface.

Figure 2 is the SEM photograph of PAN spun fiber containing 10 wt% of SPAN. It shows few fibrils compared with Figure 1.

Figure 3 is the SEM photograph of PAN spun fiber containing 20 wt% of SPAN. It shows few fibrils as like Figure 1.

Figure 4 is the SEM photograph of PAN spun fiber containing 40 wt% of SPAN. It shows few fibrils as like Figure 1.

Best Mode for Carrying Out the Invention The following experiments were carried in this invention.

Example 1. 2g of concentrated aqueous ammonia solution was added into 80g of DMF (99.5%). 18g of mixed powder of PAN

and SPAN was dissolved in this solution and stored at 40 °C.

After 30 min, it was put in a spinneret and spun. At this time, acidic solution such as 0.1-IM hydrochloric acid solution was used as a coagulation bath. Then, processes of elongation in hot water, drying, elongation in hot dry air, etc. (the same processes as in conventional PAN process), and elongation process in hot dry air for high strength industrial fibers were carried at below 150°C. PAN containing 10 wt% of SPAN showed electrical conductivity of 0.1 S/cm or more than that, and the electrical conductivity was increased as the content of SPAN was increased. The fiber showed very good electrical conductivity even though the conductivity was decreased a little after it had been soaked in water over 24 hours and dried.

The mechanical property such as tensile strength of PAN containing about 10% of SPAN was almost similar (over 90%) to the property of conventional PAN fiber. In case that SPAN is not dissolved completely with increasing of amount of SPAN, small amount of basic aqueous solution has to be added to dissolve completely.

Example 2.2g of 1M NaOH aqueous solution was added into 80g of DMF. 18g of mixed powder of PAN and SPAN was dissolved in this solution and stored at 40°C for 30 min. Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 3. Ammonia gas was forced to flow into 82g of DMF.

18g of mixed powder of PAN and SPAN was dissolved in this solution and left at 40°C for 30 min. Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 4.2g of concentrated ammonia water was added into 20g of DMF and 3.6g of SPAN powder was dissolved in that solution. 14.4g of PAN was dissolved in 60g of DMF. These two solutions were mixed well and stored at 40°C for 30 min.

Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 5.2g of concentrated ammonia water was added into 80g of DMSO (99%). 16g of mixed powder of PAN and SPAN was dissolved in this solution and stored at 40 °C for 30 min.

Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 6.2g of 1M NaOH aqueous solution was added into 80g of DMSO. 18g of mixed powder of PAN and SPAN was dissolved in this solution and stored at 40°C for 30 min. Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 7. Ammonia gas was forced to flow into 82g of DMSO for 10sec. 18g of mixed powder of PAN and SPAN was dissolved in this solution and stored at 40°C for 30 min. Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 8.2g of concentrated ammonia water was added into 20g of DMSO. 3.6g of SPAN powder was dissolved in this solution. 14.4g of PAN was dissolved in 60g of DMSO. These two solutions were mixed and stored at 40 °C for 30 min. Then it was put in a spinneret and spun. Following processes were same as those of example 1.

Example 9.2g of SPAN was completely dissolved in 36g of 0. 1M NH40H aqueous solution and 54g of NaSCN was dissolved in that solution. 8g of PAN was completely dissolved in this solution. Then it was put in a spinner and stored at 40 °C for 30 min and spun it. Following processes were same as those of example 1.

Example 10.2g of SPAN was completely dissolved in 36g of 0. 1M NaOH aqueous solution and 54g of NaSCN was dissolved in it. 8g of PAN was completely dissolved in this solution. Then it was put in a spinner and stored at 40 °C for 30 min and spun it. Following processes were same as those of example 1.

Industrial Applicability According to this invention, the product, which comes from conventional DMF process of PAN fiber, can be improved when small amount of basic aqueous solution is added into conventional solvent. The preparation process of spinning solution of PAN and SPAN is same as that of conventional process of PAN. Acidic solution is used as a coagulation bath and solvent can be recovered through the conventional recovery process of DMF, DMSO, and NaSCN. Because conductive fiber can be prepared through the conventional process without additional process, high value-added anti- static PAN fiber and film, conductive PAN fiber and film can be produced without additional process. These fibers and films can be used for anti-electrostatic clothes, shoes, gloves, etc.

They can also be applied to the screening of electromagnetic wave.