The substituting heat resistant fibers, however, are difficult to be used in the temperature range of 350 - 550 C because of insufficient heat resistance of organic fibers or ,in case of inorganic fibers, the lack of softness.

This leads to the waste of energy cased by the use of material with insufficient insulating properties or even the no-use of the insulator.

So, in many cases, asbestos are still applied, which may cause big environmental problems. PBO fiber has more than 100 degree higher heat resistant properties than current thermal resistant fibers with its thermal decomposition temperature of 650 C and can be expected to replace asbestos.

The target of our project was to prove its heat resistant performance and to develop the technology for manufacturing and processing of PBO staple fiber (cut fiber).

A bench plant for PBO staple fiber implemented at RITE-Ohtsu Laboratory in 1997.

The technology of efficient manufacturing process was developed using this bench scale plant.

Staple fibers produced by the bench plant were processed to felts, woven fabrics and knitted fabrics using industrial scale equipments.

These fabricated insulation material should possess the optimized thermal conductivity as a thermal insulator. PBO fiber has higher thermal conductivity along fiber axis than that of stainless steel. Therefore the heat conductivity of PBO insulator can be adjusted by controlling the degree of orientation of fiber in an insulator.

Cutting technology of PBO fabricated materials is so difficult that the development of cutting technology using abrasive water jet cutter should be developed.

Finally we established the fabrication technology, then made small scale conveyor system for high temper ature materials and proved the usefulness of PBO insulator for high temperature processes in place of asbestos.