chain sheet and two non meshing sheets the following charts being used for the various sheets the first guide bar corresponding to the chain structure was drawn continuously and full the second guide bar corresponding to the first non meshing sheet of partial weft was drawn continuously and 1 full 1 empty 3 full 1 empty 1 full 3 empty the third guide bar corresponding to the second non meshing sheet of partial weft was drawn continuously and 1 full 1 empty the two partial wefts were drawn so as to move under nine chain yarns by which means it was possible to finally obtain tapes separated by approximately 1 cm of width each therefore in this example 1 chain yarn in 10 that is to say ten percent was a free chain yarn within the meaning of the invention the guide bars of the two non meshing sheets moved in partial weft under three needles symmetrically in relation to one another offset from one another in the direction of production of the knit this knit corresponds to the structure represented in fig1 of the present application on leaving the knitting machine the knit was subjected to a thermosetting operation thickness approximately 0 3 mm diameter of the meshes approximately 1 mm tapes were obtained from this knit by unraveling at least two consecutive free chain yarns the tapes had the following characteristics thickness approximately.