A mixed PTFE powder according to the present invention is prepared by the steps of preparing a PTFE mixed dispersion by dispersing MoS.sub.2, Al.sub.2O.sub.3, and Al(OH).sub.3 in a PTFE emulsion; dehydrating the PTFE mixed dispersion by adding Na.sub.2CO.sub.3 into the PTFE mixed dispersion to form a cake type compound; preparing an ingot by drying the cake type compound for about 16 to 24 hours at the temperature of about 120 to 190 C.; and pulverizing the ingot in a 30-35 mesh vibrating net. An HDME PTFE yarn according to the present invention is prepared by the steps of preparing the mixed PTFE powder; adding kerosene of about 18 to 25 wt. % as solvent to the mixed PTFE powder and maintaining the resultant for about 40 to 50 hours at the temperature of about 30 to 50 C.; extruding the resulting mixed PTFE into the form of rod at about 70 to 90 C.; calendering the rod into the form of sheet at about 100 to 150 C., the width of the sheet being about 100 to 300 mm and the thickness about 0.3 to 0.7 mm; folding the sheet to become a three layered sheet and passing through the three layered sheet in an oven of about 250 to 270 C. at a speed of about 10 to 40 cm per second; and drawing the three-layered sheet at the temperature of about 450 to 500 C. at the speed of about 30 to 100 cm/s and the drawing ratio of about 200 to 600%.

A friction transmission belt includes a belt body looped over a pulley, and transmitting power. The belt body includes a rubber composition in which at least one of montmorillonite and magnesium carbonate is mixed. The friction transmission belt includes a fabric layer coating at least a surface, of the belt body, making contact with the pulley. The fabric layer has a portion making contact with at least one of the montmorillonite and the magnesium carbonate mixed into the rubber composition.

A joined V-belt includes: a plurality of wrapped V-belt portions; and a tie band, in which outer peripheral surfaces of the wrapped V-belt portions are connected by the tie band. Each of the wrapped V-belt portions includes a belt body and a cover fabric covering an outer surface of the belt body. The belt body includes a tension member layer including a tension member, a tension rubber layer laminated on a belt outer peripheral side of the tension member layer, and a compression rubber layer laminated on a belt inner peripheral side of the tension member layer. The tie band includes a short fiber-containing rubber layer in which a short fiber is oriented in a belt width direction, and the short fiber-containing rubber layer includes a plurality of rib portions extending in a belt longitudinal direction.