In flow of an anisotropic solution of poly-(p-phenylene terephthalamide) through the channels of spinneret openings in a stream at a distance of 0.7R from the axis of the channel, two layers are formed, and the outer layer is deformed 2.7 times more than the inner layer. Subsequent longitudinal deformation of the jet flowing out primarily causes a break in the outer layer, accompanied by a periodic change in the diameter of the jet, known as “deformation resonance”. Increasing the air gap causes expansion of the jet diameter, accompanied by a further decrease in the flow rate in the outer layer and a decrease in the fibre speed at which deformation resonance appears. The actual critical deformation, calculated as the ratio of the fibre take-off speed to the actual speed in the outer layer, remains constant, equal to 66±6, which is approximately equal to the limiting deformation of the jet of a solution of PPTA in the absence of resonance.
