Abstract: A process for preparing highly oriented undrawn core-sheath type conjugated polyester fibers including the step of spinning a polyester as the sheath polymer and a polymer having a larger gradient of elongational viscosity with the temperature than that of the sheath polymer as a core polymer at a spinning speed of about 4000 to 12000 m/min.

Abstract: A highly oriented undrawn polyester fiber which is crystalline such that the fiber is capable of exhibiting a diffraction peak observable in a wide angle X-ray diffraction image of the fiber and has a birefringence of 0.015 to 0.05.A process for preparing highly oriented undrawn core-sheath type conjugated polyester fibers including the step of spinning a polyester as the sheath polymer and a polymer having the larger gradient of elongational viscosity with the temperature than that of the sheath polymer at a spinning speed of about 4000 to 12000 m/min.A textured yarn made of said highly oriented undrawn polyester fibers and a process for preparing the textured yarn.

Abstract: A heat-sensitive mimeograph stencil which gives a high quality of image because the permeation of printing ink is not hindered by an adhesive, and which is free from the problems caused by an adhesive, that is, poor resistance to ink, sticking to thermal head, and generation of toxic chlorine, as well as production process thereof is disclosed. The heat-sensitive mimeograph stencil is prepared by thermally adhering a polyester film and a porous support consisting essentially of polyester fibers and then co-stretching the resultant, and the peeling strength between said polyester film and said porous support is not less than 1 g/cm, so that the printed matter obtained by mimeograph using the stencil has very high quality of image.

Abstract: An improved electric resistance heating element made of a carbon material, provided around its surface with a layer essentially comprising carbon fiber, and an improved electric resistance heating furnace using the heating element.

Abstract: A process for producing a carbon fabric wherein a fabric, which is made of an acrylonitrile polymer fiber having a fusing temperature (T.sub.f) of at least 310.degree. C. and exhibits a free areal shrinkage of not larger than 50%, is heated in an active gas atmosphere under conditions such that shrinkage of the fabric is permitted, thereby to be stablized, and then, the fabric is carbonized in an inactive gas atmosphere.