Patent Publication Number: US-2023158787-A1

Title: Plant and method for laminating corrugated cardboard

Description:
The present invention relates to a plant for laminating cardboard, and in particular for laminating corrugated cardboard. 
     Corrugated cardboard is particularly used to manufacture various types of packaging. In this case, it concerns the production of display cabinets for products for sale. Such display cabinets, in addition to having a shape adapted to contain and display the products, also have a marketing function, therefore they are usually printed with the colors and the logos of the manufacturers of such products. A further use of corrugated cardboard concerns the production of food containers. 
     Manufacturing such display cabinets by printing a sheet of paper according to the required graphics is known. Subsequently, such sheet is laminated and then applied on top of the corrugated cardboard. 
     The cardboard is then cut, folded, glued and finished to form the desired display cabinet. 
     Such known methods for laminating corrugated cardboard display cabinets still have numerous disadvantages, and in particular they are laborious and expensive. 
     Attempts have been made to carry out the lamination of corrugated cardboard through the known lamination plants, although, current technologies involve an inevitable and considerable damage of the final product. 
     In fact, the working pressures implemented by such plants, necessary to obtain a good coupling between the plastic coating and the cardboard, tend to almost flatten the waves of the corrugated cardboard completely. 
     It is therefore the object of the present invention to provide a plant for laminating cardboard, and in particular corrugated cardboard, so as to obviate at least some of the drawbacks highlighted in the prior art. 
     It is a particular object of the present invention to provide a plant for laminating cardboard, and in particular corrugated cardboard, which carries out such lamination in a manner which does not damage the product, is more efficient, quick and cost effective. 
     These and other purposes are achieved by means of a plant for laminating cardboard according to claim  1 . 
     Dependent claims relate to preferred and advantageous embodiments. 
    
    
     
       Further features and advantages of the present invention will become more apparent from the description of some preferred embodiments thereof, given below by way of non-limiting example with reference to the accompanying drawings, in which: 
         FIG.  1    shows a partial perspective view of a plant for laminating cardboard, according to an embodiment of the invention; 
         FIG.  2    shows a side view in longitudinal section of a plant for laminating cardboard, according to a further embodiment of the invention; 
         FIG.  3    shows a side view of a plant for laminating cardboard, according to a further embodiment of the invention; 
         FIG.  4    shows a perspective figure of a plant for laminating cardboard, according to an embodiment of the invention; 
         FIG.  5    shows a perspective view of a detail of a plant for laminating cardboard, according to an embodiment of the invention. 
     
    
    
     With reference to the Figures, a plant for laminating cardboard, and in particular corrugated cardboard, by means of an adhesive plastics film  11 , is generally indicated with reference numeral  1 . 
     Adhesive plastics film  11  means a plastics film on which a layer of heat-activated adhesive material is applied. 
     The plant  1  comprises a supply station  3 . 
     Preferably, the supply station  3  is configured to allow stacking a pile of rough cardboard sheets  16  to be processed. 
     Rough cardboard sheet  16  means a printed and/or corrugated cardboard sheet  16 . 
     The supply station  3  comprises supplying means  17  of rough cardboard sheets  16  in a feeding direction  18 . Preferably, the supplying means  17  comprise a sheet feeder head. 
     The sheet feeder head  17  is configured to take, in sequence, i.e. one by one, a single rough cardboard sheet  16  of the stack of cardboard sheets to be processed  16 , and feed a succession of single rough cardboard sheets  16  in a feeding direction  18 . 
     The plant further comprises an application station  6 , arranged in the feeding direction  18 . 
     The application station  6  comprises an application roller  20  which comprises heating means  24 . 
     The application roller  20  is configured to be partially wrapped by the adhesive plastics film  11 . 
     Furthermore, the application roller  20  is structured to be thermally activated, by means of the heating means  24 , and in turn reactivate the partially wrapped adhesive plastics film  11 . 
     Furthermore, the application roller  20  is configured to apply the thermally activated adhesive plastics film  11  to the rough cardboard sheet  16  so that the adhesive plastics film  11  adheres to the rough cardboard sheet  16  in order to form a coated cardboard sheet  22 . Advantageously, the adhesive plastics film  11  is applied to, and adheres to each rough cardboard sheet  16  placed in sequence, so as to form a succession of coated cardboard sheets  22 . 
     A succession of coated cardboard sheets  22  means a succession of single coated cardboard sheets with a continuous adhesive plastics film. 
     Furthermore, the application roller  20  is configured to advance the coated cardboard sheet  22 , advantageously each coated cardboard sheet  22  of the succession of coated cardboard sheets  22 , in the feeding direction  18 . 
     Advantageously, a plant  1  thereby configured, ensures a lamination of the rough cardboard  16  directly onto the corrugated material by means of an adhesive plastics film  11 , without the interposition of printed sheets, which reduces processing times and costs, and does not require passages in other machinery, with a consequent reduction of labor costs. 
     With a further advantage, a plant  1  thus configured achieves a high-quality lamination, which preserves the corrugated structure and the physical properties of the corrugated cardboard. 
     Advantageously, the plant  1  thus configured may be directly fed with corrugated cardboard sheets, and produces, as a final product, a sheet of corrugated cardboard optimally coated with a plastics film. 
     According to an embodiment of the invention, the plant  1  for laminating cardboard comprises a loading station  2 . 
     The loading station  2  comprises loading means  12  configured to move at least one bobbin of adhesive plastics film  15  from a storage position  13 , in which the at least one bobbin of adhesive plastics film  15  is loadable, to an unwrapping position  14 , in which the bobbin of adhesive plastics film  15  unwraps the adhesive plastics film  11 . 
     According to an embodiment, the plant  1  further comprises a feeding and registration station  4 , arranged in the feeding direction  18  between the supply station  3  and the coating station  6 . 
     The feeding and registration station  4  comprises feeding and registration means  19  which are configured for moving and aligning the cardboard sheets  16  to be processed, in the feeding direction  18  and/or transversally to the feeding direction  18 . 
     Thereby, the possible micro-misalignments, that the rough cardboard sheets  16  fed by the sheet feeder head  17  may have, are obviated. 
     According to an embodiment, the plant  1  further comprises a separating station  7 , arranged in the feeding direction  18 , downstream of the application station  6 . 
     The separating station  7  comprises separation means  5  for separating the succession of coated cardboard sheets  22 , at the contact zone between two consecutive coated cardboard sheets  22 . 
     Thereby, a sequence of single and individual coated cardboard sheets  22  is obtained. 
     According to an embodiment, the plant  1  further comprises a stacking station  9 , arranged in the feeding direction  18  downstream of the separating station  7 , and configured to stack a pile of coated cardboard sheets  22 . 
     According to an embodiment, the application station  6  comprises a drawing-in system  21 , comprising a plurality of tension rollers. 
     Advantageously, the plurality of tension rollers reduces the wrinkles of the adhesive plastics film  11  unwrapped from the bobbin of adhesive plastics film  15 . 
     The drawing-in system  21  is structured to wrap the adhesive plastics film  11  unwrapped from the bobbin of adhesive plastics film  15 , around the application roller  20 . 
     According to an embodiment, the plant  1  for laminating cardboard further comprises a launching station  8 , arranged in the feeding direction  18  and interposed between the separating station  7  and the stacking station  9 . 
     The launching station  8  comprises launching means  23  configured to distance, in the feeding direction  18 , a single coated cardboard sheet  22  from the following one, so as to create a space between the various coated sheets  22 . 
     Advantageously, this allows to isolate a single coated cardboard sheet  22 , and to facilitate a following stacking step. 
     According to an advantageous embodiment, the launching means  23  comprise suction means  25 , which accelerate and subsequently decelerate a single coated cardboard sheet  22 , so as to temporarily distance it from the succession of coated cardboard sheets  22 . 
     Loading Station  2   
     According to an embodiment, the loading station  2  comprises a motorized platform  26 . 
     The motorized platform  26  may be moved between the storage position  13  and the unwrapping position  14 . 
     Furthermore, the motorized platform  26  is configured to support at least one bobbin of adhesive plastics film  15 , preferably two. 
     According to a preferred embodiment, the storage position  13  is located at the plant  1 , at ground level. 
     Advantageously, this simplifies and increases the safety of the process for storing bobbins of adhesive plastics film  15 , of considerable weight, to be fed to the plant  1 . 
     Furthermore, the unwrapping position  14  is located at the plant  1 , at a higher level with respect to the storage position  13 , in a top zone of the plant  1 . 
     Advantageously, this simplifies the process for unrolling the bobbin of adhesive plastics film  15 , since the unwrapping position  14  is at a higher level with respect to the drawing-in system  21  which then feeds the application roller  20 . 
     According to an embodiment, the plant  1  forms a calender access chamber  27 . 
     The calender access chamber  27  extends inside the plant  1  and is configured to allow the access of operators inside the plant  1 , and in particular the access inside the drawing-in system  21 . 
     The plant  1  also forms an entrance  28 , for the access from the outside to the calender access chamber  27 . 
     The entrance  28  is formed at the storage position  13 . 
     When the motorized platform  26  is in the storage position  13 , the motorized platform  26  overlaps the entrance  28 , preventing the access to the calender access chamber  27 . 
     When the motorized platform  26  is in the unwrapping position  14 , the motorized platform  26  opens the entrance  28 , thus allowing the access to the calender access chamber  27 . 
     Advantageously, such configuration reduces the size of the plant  1 , since the calender access chamber  27  is formed inside the plant  1 , and, at the same time, it increases the safety of the plant  1 , since the motorized platform  26  may prevent the access to the calender access chamber  27 , which, being inside the plant  1 , is in any case a zone more exposed to the risk of accidents. 
     According to an embodiment, a gangway  34  is connected integral with the motorized platform  26 , and is positioned above the motorized platform  26 . 
     The gangway  34  allows the passage of operators, when the motorized platform  26  is in the storage position  13 . 
     According to an embodiment, the loading station  2  comprises, at the unwrapping position  14 , at least one unwrapping reel  35  and a telescopic loading arm  36 . 
     Advantageously, two unwrapping reels  35  are provided, so as to increase the efficiency and speed of the coating process. 
     The telescopic loading arm  36  is configured to extend telescopically when the motorized platform  26 , carrying the at least one bobbin of adhesive plastics film  15 , is at the unwrapping position  14 , to harpoon the at least one bobbin of adhesive plastics film  15  and to slip it onto the at least one unwinding reel  35  in the unwrapping position  14 . 
     According to an embodiment, the loading station  2  comprises a height adjustor configured to adjust the height of the motorized platform  26  carrying the bobbins of adhesive plastics film  15 . 
     Advantageously, by means of the height adjuster it is possible to adjust the height at which the bobbins of adhesive plastics film  15  are located, so as to facilitate the loading thereof on the unwrapping reels  35  by means of the telescopic loading arm  36 . 
     According to an embodiment, the loading station  2  comprises, at the unwrapping position  14 , a trimming system  37  configured to trim the adhesive plastics film  11  unrolled from the bobbin of adhesive plastics film  15 . 
     Advantageously, by means of the trimming system  37  it is possible to adjust the width of the adhesive plastics film  11  to be conveyed towards the application roller  20 , so that the width of the adhesive plastics film  11  conforms to the width of the rough cardboard sheet  16  to be coated. 
     Supply Station  3   
     According to an embodiment, the sheet feeder head  17  comprises suction cups adapted to take a single rough cardboard sheet  16 , without damaging or deforming the corrugations of the rough cardboard  16 . 
     Furthermore, the sheet feeder head  17  comprises a dividing element, configured to block the pile of rough cardboard sheets  16  during the taking of the upper rough cardboard sheet  16 , preventing further rough cardboard sheets  16  from being taken together with the upper sheet. 
     Feeding and Registration Station  4   
     According to an embodiment, the feeding and alignment means  19  comprise an overlap management system. 
     The overlap management system is configured to adjust the overlap and/or the spacing of the ends of two consecutive rough cardboard sheets  16 . 
     Advantageously, according to the type of rough cardboard  16  to be processed, the overlap management system is configured to overlap the ends of the cardboard sheets  16 , in case it is required to overlap them, or to space them, in case this is not required. 
     Application Station  6   
     According to an embodiment, the application station  6  comprises a counter-deformation system  38 , arranged downstream of the application roller  20  in the feeding direction  18 . 
     The counter-deformation system  38  comprises a plurality of deflection rollers configured to convey the coated cardboard sheet  22  exiting the application roller  20  and to press it, so as to obviate any flatness defects of the coated cardboard sheet  22 . 
     In fact, the thermal application of the adhesive plastics film  11  on the rough cardboard sheet  16  may possibly cause a deformation of the resulting coated cardboard sheet  22  which would be obviated by the counter-deformation system  38 . 
     According to an embodiment, the application roller  20  is coated with an elastic material  32 , preferably in rubber. 
     Advantageously, by means of the elastic material  32 , the application roller  20  uniformly applies the adhesive plastics film  11  so as to accommodate the roughness and corrugations of the rough cardboard sheet  16  to be coated, without damaging it. 
     According to an embodiment, the application station  6  comprises height adjustment means  33  configured to adjust the height of the application roller  20 , with respect to the rough cardboard sheet  16 . 
     Advantageously, the adjustment of the height of the application roller  20  allows to predetermine the compression force that the application roller  20  will implement in coating the rough cardboard sheet  16  with the adhesive plastics film  11 . 
     Thereby, the application roller  20  efficiently applies the adhesive plastics film  11  to the rough cardboard sheet  16  with an adequate compression rate, without however damaging or deforming the corrugations of the rough cardboard sheet  16 . 
     According to an embodiment, in the operating configuration, the adhesive plastics film  11  wraps around about ¾ of the outer surface of the application roller  20 . 
     According to an embodiment, the application roller  20  heats the adhesive plastics film  11  up to a temperature between 80° C. and 120° C. 
     Advantageously, this allows to effectively heat and activate the adhesive layer of the adhesive plastics film  11 , while reducing the size of the plant  1 , since the heating is provided by means of a single component, i.e., the application roller  20 . 
     According to an embodiment, the application station  6  comprises a pressure roller  10 , opposite to the application roller  20  with reference to the adhesive plastics film  11 . Preferably, the pressure roller is made of a rigid material. 
     The pressure roller  10  is configured to counter pressure the application roller  20  when conveying the coated cardboard sheet  22  in the feeding direction  18 . 
     According to an embodiment, both the application roller  20  and the pressure roller  10  are motorized. 
     Advantageously, the motorization of both the application roller  20  and the pressure roller  10  allows to reduce the pressure force acting on the coated cardboard sheet  22  to convey it in the feeding direction  18 , so as not to damage or deform the corrugations of the coated cardboard sheet  22 . 
     Separating Station  7   
     According to an embodiment, the separating station  7  comprises no-crush wheels  29 , which are configured to drag the coated cardboard sheets  22  in the feeding direction  18 . 
     Advantageously, the use of no-crash wheels  29  ensures a dragging which does not damage or deform the coated cardboard sheets  22  directed in the feeding direction  18 . 
     According to an embodiment, the separating station  7  comprises an end sheet detector  31 . 
     The end sheet detector  31  is configured to detect a separation zone between two consecutive coated cardboard sheets  22 , and control the separation means  5  to cut the plastic coating on the end part of the coated cardboard sheets  22 . 
     According to an embodiment, the end sheet detector  31  is configured to detect the separation zone between two consecutive coated cardboard sheets  22 , both in case the two coated cardboard sheets  22  are detached and in case they slightly overlap, or in case of overlap. Therefore, separation zone means the zone of detachment and/or overlap between two consecutive coated cardboard sheets  22 . 
     According to an embodiment, the separation means  5  comprise a flying shear system  30  comprising a thermal knife, configured to make the cut according to the commands of the end sheet detector  31 . The flying shear system  30  is configured to adjust the speeds of rotation of the thermal knife with respect to a rotation axis orthogonal to the feeding direction  18 . The flying shear system  30  is configured to adjust the height and the inclination of the thermal knife with respect to the plane of the coated cardboard sheets  22 . 
     Alternatively, the separation means  5  comprise a cold-cutting system, configured to perform the cut on the basis of the commands from the end sheet detector  31  and comprising a blade configured to slide in the transverse and/or diagonal direction with respect to the plane of the coated cardboard sheets  22 , depending on whether or not the coated cardboard sheets  22  are temporarily stopped during the cutting, at the separation zone between the coated cardboard sheets  22 . 
     Advantageously, the use of a flying shear system  30  reduces the overall size of the plant  1  and ensures a precise cut, with an accuracy of a tenth of a millimeter. 
     According to a preferred embodiment, the adhesive plastics film  11  consists of polypropylene or polyester or polylactic acid (PLA) or nylon or polyethylene. 
     Method for Laminating Cardboard 
     According to a further aspect of the invention, a method for laminating cardboard, and in particular corrugated cardboard, using an adhesive plastics film  11 , comprises the following steps: 
     Having a plant  1  for laminating cardboard, as described above. 
     In a loading station  2 , storing at least one bobbin of adhesive plastics film  15  in a storage position  13  and moving the bobbin of adhesive plastics film  15  from the storage position  13  into an unwrapping position  14 . 
     Unwrapping the adhesive plastics film  11  from the bobbin of adhesive plastics film  15  and conveying the adhesive plastics film  11  to a drawing-in system  21  and to an application roller  20 . 
     In a supply station  3 , taking a rough cardboard sheet  16 , preferably from a pile of rough cardboard sheets  16  that is stacked in the supply station  3 , and supplying the rough cardboard sheet  16  in a feeding direction  18 . 
     In a feeding and registration station  4 , moving and registering the rough cardboard sheet  16  in the feeding direction  18  towards the application roller  20  and adjusting the overlap and/or spacing between the ends of two consecutive rough cardboard sheets  16  by means of an overlap management system. 
     In an application station  6 , heating the application roller  20 , thermally activating the adhesive plastics film  15  and storing the thermally activated adhesive plastics film  15  on the rough cardboard sheet  16  so that the adhesive plastics film  11  adheres to the rough cardboard sheet  16 , advantageously to each rough cardboard sheet  16  of the succession of rough cardboard sheets  16 , so as to form a coated cardboard sheet  22 , advantageously a succession of coated cardboard sheets  22 , and releasing each coated cardboard sheet  22  in the feeding direction  18 . 
     In a separating station, separating two consecutive coated cardboard sheets  22 , preferably by cutting the succession of coated cardboard sheets  22  at a separation zone between two consecutive coated cardboard sheets  22 , so as to obtain a sequence of single and individual coated cardboard sheets  22 . 
     In a stacking station  9 , stacking the pile of coated cardboard sheets  22 . 
     According to an advantageous embodiment, in a launching station  8  arranged between the separating station  7  and the stacking station  9 , a space is created between a single coated cardboard sheet  22  and the subsequent coated cardboard sheets that follow it. 
     According to an embodiment, the conveying and fixing of the adhesive plastics film  11  on the drawing-in system  21  is performed manually, by an operator. 
     According to an embodiment, only at the beginning of the manufacturing process, the succession of coated cardboard sheets  16  is manually conveyed to the separating station  7  by an operator. 
     Advantageously, the conveyance performed manually by an operator simplifies plant  1  and reduces the costs for the manufacturing thereof. 
     Obviously, those skilled in the art will be able to make modifications or adaptations to the present invention, without however departing from the scope of protection of the claims below.