FIELD: metallurgy.
SUBSTANCE: group of inventions refers to procedure for cross stretch of film band made out of thermo-plastic material not directed or directed lengthwise and to procedure for production of film with cross shrinkage. The procedure consists in supply of not directed or stretched lengthwise film into a cross-stretching frame. The cross-stretching frame consists of heating field, stretching field and of stabilisation field. In the beginning of the first heating field film is gripped with clamps of the clamping chain on both ends and is heated in heating field to temperature TQ of the cross stretch. Film is stretched in the cross direction in the adjacent stretch field by means of a diverging V-shaped guiding chain with clamps; it stays in stabilisation fields at temperature TF, also TQ > TF. End zones of film are heated so, or thermo-insulated so in the stretch field and/or in stabilisation fields, that they have higher temperature, than the middle of the film band during cross stretching and/or during stabilisation. There is produced film with cross shrinkage from 3 to 25 % by implementation of the said procedure.
EFFECT: production of film with more uniform cross shrinkage along width of film band at raised temperature.
20 cl, 12 dwg
