The invention relates to a polygonal container comprising a tubular polygonal body (10) with an even number of flat faces (11) numbering more than four, which is formed by a strip of corrugated cardboard (19) rolled up at least two full turns and adhered to itself by means of lines of glue (30) transverse to the channels of the corrugated cardboard, forming a multilayer wall (13); a base body (20) defined by a base panel of cut and folded stiff double-faced corrugated cardboard (24) attached around an end portion of the tubular polygonal body (10). The method comprises forming the tubular polygonal body by means of rolling the strip of corrugated cardboard around a polygonal rotary drum (51) and subsequently attaching to a base body (20).

Method for producing cardboard tubes by winding a plurality of ribbons (U, L) onto a spindle (1), a preset number of the ribbons (U, L) being glued in correspondence of the lower or radial inner surface thereof, characterized in that a predetermined amount of supplementary quick setting glue is applied on the lower surface of the last ribbon (U) destined to be wound on the spindle (1), in proximity to at least a longitudinal edge (BU) of the ribbon (U) forming a corresponding stripe of quick setting glue (G) astride of a section (ST) of the same ribbon interested or intersected by a subsequent cutting action executed downstream of the spindle (1).

Method for producing cardboard tubes by winding a plurality of ribbons (U, L) onto a spindle (1), a preset number of the ribbons (U, L) being glued in correspondence of the lower or radial inner surface thereof, characterized in that a predetermined amount of supplementary quick setting glue is applied on the lower surface of the last ribbon (U) destined to be wound on the spindle (1), in proximity to at least a longitudinal edge (BU) of the ribbon (U) forming a corresponding stripe of quick setting glue (G) astride of a section (ST) of the same ribbon interested or intersected by a subsequent cutting action executed downstream of the spindle (1).

A convolutely wound tube (1) is formed of a composite sheet including a first sheet (6) and a second sheet (5). The convolutely wound tube includes a first segment (66) formed of a plurality of convolute windings (2) of the first sheet, a second segment (70) formed of directly adhered and overlapping portions of the first sheet and the second sheet, and a third segment (68) formed of the second sheet wrapped about and overlying the first sheet. The second segment is an underwrap portion positioned between a layer of the first sheet and a layer of the second sheet.

A convolutely wound tube (1) is formed of a composite sheet including a first sheet (6) and a second sheet (5). The convolutely wound tube includes a first segment (66) formed of a plurality of convolute windings (2) of the first sheet, a second segment (70) formed of directly adhered and overlapping portions of the first sheet and the second sheet, and a third segment (68) formed of the second sheet wrapped about and overlying the first sheet. The second segment is an underwrap portion positioned between a layer of the first sheet and a layer of the second sheet.

A method for producing a convolute paper core of a desired width and thickness, the method including unwinding paper from a paper roll, thereby creating unwound paper, conveying the unwound paper to a cutting position in a feeding direction, cutting the unwound paper, thereby creating a paper sheet having a length L, conveying the paper sheet from the cutting position to a mandrel in a winding direction, wherein the winding direction is perpendicular to the feeding direction, adhesively and convolutely winding the paper sheet on the mandrel so as to produce a paper core, so that a width W of the paper core is equal to the length L, and repeating the steps of unwinding, conveying, cutting, conveying and adhesively and convolutely winding a plurality of paper sheets until the paper core has the desired thickness.

A method for producing a convolute paper core of a desired width and thickness, the method including unwinding paper from a paper roll, thereby creating unwound paper, conveying the unwound paper to a cutting position in a feeding direction, cutting the unwound paper, thereby creating a paper sheet having a length L, conveying the paper sheet from the cutting position to a mandrel in a winding direction, wherein the winding direction is perpendicular to the feeding direction, adhesively and convolutely winding the paper sheet on the mandrel so as to produce a paper core, so that a width W of the paper core is equal to the length L, and repeating the steps of unwinding, conveying, cutting, conveying and adhesively and convolutely winding a plurality of paper sheets until the paper core has the desired thickness.

Method for producing cardboard tubes by winding a plurality of ribbons (U, L) onto a spindle (1), a preset number of the ribbons (U, L) being glued in correspondence of the lower or radial inner surface thereof, characterized in that a predetermined amount of supplementary quick setting glue is applied on the lower surface of the last ribbon (U) destined to be wound on the spindle (1), in proximity to at least a longitudinal edge (BU) of the ribbon (U) forming a corresponding stripe of quick setting glue (G) astride of a section (ST) of the same ribbon interested or intersected by a subsequent cutting action executed downstream of the spindle (1).

Method for producing cardboard tubes by winding a plurality of ribbons (U, L) onto a spindle (1), a preset number of the ribbons (U, L) being glued in correspondence of the lower or radial inner surface thereof, characterized in that a predetermined amount of supplementary quick setting glue is applied on the lower surface of the last ribbon (U) destined to be wound on the spindle (1), in proximity to at least a longitudinal edge (BU) of the ribbon (U) forming a corresponding stripe of quick setting glue (G) astride of a section (ST) of the same ribbon interested or intersected by a subsequent cutting action executed downstream of the spindle (1).

A plastic film roll includes: a convolute cardboard tube including a tubular body having a tubular body wall formed by a plurality of layers of a straight rolled cardboard sheet having a weight equal to or less than 300 gsm; a plastic film wound about the convolute cardboard tube to form a plurality of plastic film windings around the convolute cardboard tube, the plastic film windings creating a radial compression force equal to or greater than 10 bar on the tubular body wall, wherein the cardboard sheet includes a plurality of fibers, at least a majority of the fibers being substantially aligned in a tangential direction relative to the tubular body to allow the convolute cardboard tube to resist the radial compression force.