CARDBOARD WITH CORRUGATED DOUBLE LAYER, CARDBOARD MANUFACTURE METHOD AND APPARATUS Russian patent published in 2000 - IPC

FIELD: cardboard production. SUBSTANCE: cardboard has first facing, first corrugated filler continuously applied onto first facing for forming single-sided corrugated cardboard, second corrugated filler continuously applied onto first corrugated filler of single-sided single-layer corrugated cardboard for forming single-sided double-layer corrugated cardboard, and second facing continuously applied onto surface of second corrugated filler of single-sided double-layer corrugated cardboard. First corrugated filler has predetermined corrugation pitch and height, and has convex and concave portions, each of predetermined curvature. First corrugated filler is joined at predetermined connecting points to first facing between convex portions of first filler and first facing. Second corrugated filler has corrugation pitch and height equal to or different from that of corrugation of first corrugated filler, and has convex and concave portions of predetermined curvature different from predetermined curvature of first corrugated filler for defining shock-absorbing spaces between first and second corrugated fillers. Second corrugated filler is glued to first corrugated filler at connecting points between convex portions of second corrugated filler and convex portions of first corrugated filler. Second corrugated filler is joined to second corrugated facing at predetermined points of second corrugated filler and second corrugated facing junction portions. EFFECT: improved structure of cardboard, increased strength of packaging material sheets and enhanced reliability in protecting packaged goods. 23 cl, 5 dwg