METHOD OF OBTAINING EXTRUDED FOAM POLYMER IN STAGE-BY-STAGE MOULDING Russian patent published in 2014 - IPC B29C44/26 

FIELD: chemistry.

SUBSTANCE: claimed invention relates to a method of obtaining an extruded foam polymer. The technical result is achieved by the method of obtaining the extruded foam polymer, which includes a stage of obtaining a foamed polymer composition in an extruder. The foamed polymer composition contains a foam generator and a polymer matrix, which contains a polymer component. An initial temperature in the extruder exceeds the temperature of the polymer component softening, and initial pressure is sufficiently high to exclude foaming of the polymer composition to be foamed. At the stage of extrusion of the polymer composition to be foamed into atmosphere under pressure, lower than the initial pressure, and expansion of the polymer composition to be foamed to obtain the foam polymer, before cooling the polymer composition to be foamed expands to a degree of expansion in width, equal to 30:1, with simultaneous passing through and contact with the opposite moulding plates. The said plates form two successive limiting sections in the direction of extrusion. The moulding plates in each limiting section include parallel limiting walls, which constrain expansion of the foamed composition in the direction of the width dimension. A limiting section, the closest to the extruder, has parallel walls, determining clearance in the direction of the width dimension, lying in the range of 10-40 times exceeding the height of an output hole of the foaming head, and which is smaller than clearance between the parallel walls, determining the second limiting section.

EFFECT: increased homogeneity of the extruded foam polymer.

10 cl, 1 tbl, 1 ex