Abstract:
The present invention relates to for a continuous production of a web of a composite material. The process comprises the steps of: providing a web of honeycomb material; providing at least one web of face sheet material having a corrugated medium with at least one linerboard on at least one face thereof; carrying the web of honeycomb material and the at least one web of face sheet material along a production line; and adhesively applying the at least one web of face sheet material to one face of the honeycomb material while the honeycomb material is being conveyed through the production line and maintained in an expanded state. The present invention also relates to a packaging material manufactured with a process described hereinabove and an apparatus to manufacture same.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of manufacturing a composite material and, more particularly, to a process for manufacturing a honeycomb composite material and an apparatus to manufacture same. The composite material can be used for packaging and building applications. 
     BACKGROUND OF THE INVENTION 
     Safe product delivery requires a strong and efficient packaging material which can hold up under tough conditions. For the selection of a packaging material, the important criteria are its weight, its recyclability, its mechanical properties, and its cost. 
     Foam materials are widely used since they are inexpensive and lightweight. However most of them are not environmentally friendly and sometimes foam materials can generate static electricity when in contact with another object. Paper honeycomb materials are fully recyclable, lightweight, and inexpensive. Honeycomb materials probably offer the best strength to weight ratio of any material available. However, they do not offer a good compressive strength in the plane of the material (edge compression resistance). Corrugated cardboards are also fully recyclable, lightweight, and inexpensive. However, important quantities of material are necessary to produce safe containers with corrugated cardboard, which increase the packaging cost. Moreover, corrugated cardboard having anti-static electricity properties can be obtained. 
     Massive applications of the packaging materials require cost efficient and continuous productions to be competitive with the existing products. Furthermore, better mechanical properties to allow weight and raw material cost savings are essential for packaging applications. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a process to manufacture a honeycomb composite material that is lightweight, inexpensive, has high mechanical properties, and is preferably recyclable. 
     It is another object of the present invention to provide a manufacturing process for a lightweight composite material that has high mechanical properties. 
     It is a further object of the present invention to provide an apparatus for continuous production of a lightweight composite material. 
     According to one aspect of the present invention, there is provided a process for a continuous production of a web of a composite material. The process comprises the steps of: providing a web of honeycomb material; providing at least one web of face sheet material having a corrugated medium with at least one linerboard on at least one face thereof; carrying said web of honeycomb material and said at least one web of face sheet material along a production line; and adhesively applying said at least one web of face sheet material to one face of said honeycomb material while said honeycomb material is being conveyed through the production line and maintained in an expanded state; wherein the step of providing the at least one web of face sheet material further includes providing the face sheet material in a stack and unfolding the stacked face sheet material into the at least one web. 
     According to another aspect of the present invention, there is provided a packaging material manufactured with the process described hereinabove. 
     According to a further aspect of the present invention, there is provided an apparatus for a continuous production of a web of a composite material. The apparatus comprises at least one carrier for moving a web of honeycomb material along the apparatus; at least one carrier for moving at least one web of a face sheet material along the apparatus, the face sheet material having a corrugated medium with a linerboard on at least one face thereof; at least one laminator for adhesively applying the at least one web of the face sheet material to a face of the web of honeycomb material in an expanded state. 
     According to another aspect of the present invention, there is provided a packaging material manufactured with the apparatus described hereinabove. 
     The term paper is herein intended to means any wood fiber based materials such as cardboard, kraft paper, recycled paper, medium, chipboard, bleached or not, and the like. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: 
         FIG. 1  is a perspective view of a composite material according to the prior art, the composite material is manufactured manually; 
         FIG. 2  is an exploded perspective view of the composite material of  FIG. 1 ; 
         FIG. 3  is an exploded perspective view of a composite material manufactured with a process according to an embodiment of the present invention; 
         FIG. 4  is an exploded perspective view of a composite material manufactured with a process according to another embodiment of the present invention, the composite material has only one face sheet including a corrugated medium; 
         FIG. 5  is a schematic view of a process according to a first embodiment of the present invention, wherein the process is used to manufacture the composite material of  FIG. 3 ; 
         FIG. 6  is a schematic view of a process according to a second embodiment of the present invention, wherein the process is used to manufacture the composite material of  FIG. 4  and the face sheets are bonded to a core portion with a hot melt adhesive; 
         FIG. 7  is a top plan view of an apparatus according to an embodiment of the present invention, the apparatus is used to carry out the composite material of  FIG. 4  with the process of  FIG. 6 ; and 
         FIG. 8  is a side elevation view of the apparatus of  FIG. 7  according to the present invention. 
     
    
    
     It will be noted that throughout the appended drawings, like features are identified by like reference numerals. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring simultaneously to  FIGS. 1 and 2 , there is shown a composite material  10  of the prior art typically used in packaging applications. The composite material  10  has a core portion  12  including an expanded honeycomb material  14  and two linerboards  16  laminated on the honeycomb material  14 . The linerboards  16  are usually compulsory to maintain the honeycomb material  14  in an expanded state. On each linerboard  16 , a face sheet  18  is manually laminated. The face sheet  18  is constituted of a corrugated medium  20  and two linerboards  22  laminated on each side of the corrugated medium  20 . The composite material  10  has adequate mechanical properties for packaging applications. However, since the face sheets  18  are laminated manually on the core portion  12 , it cannot be used widely due to its high manufacturing cost. 
     It is highly desirable to produce in a continuous manner a composite material such as the composite material described hereinabove, to reduce the manufacturing costs. Moreover, it is also desirable to reduce the raw material necessary to produce the composite material. When the composite material  10  is manufactured manually, two linerboards  16 ,  22  are contiguous on each side of the honeycomb material  14 . As mentioned earlier, the linerboards  16  are necessary to maintain the honeycomb material  14  in an expanded state. 
     The present invention provides an apparatus to continuously manufacture a composite material similar to the composite material  10  and, preferably, without the double linerboards  16 ,  22  on each side of the honeycomb material  14 . 
     Referring to  FIG. 3 , there is shown a composite material  10   a  manufactured by a production line  30  (or a process line) ( FIG. 5 ). As the composite material  10 , the composite material  10   a  has a core portion  12  and two face sheets  18  laminated on the core portion  12 . The core portion  12  solely includes a honeycomb material  14  in an expanded state. As opposed to the prior art ( FIGS. 1 and 2 ), it does not include linerboards  16  laminated on each side of the honeycomb material  14 . The core portion  12  has two faces  34   a ,  34   b . The cells of the honeycomb material  14  have an hexagonal shape but any other nested shape can be used. Each face sheet  18  is constituted of a corrugated medium  20  and two linerboards  22  laminated on each side of the corrugated medium  18 . Each face sheet  18  is preferably directly laminated on the honeycomb material  14  forming the core portion  12  thereby reducing the raw material necessary to manufacture the composite material  10   a.    
     One skilled in the art will understand that the face sheets  18  can include only one linerboard  22  laminated on one side of the corrugated medium  20 . In that case, either the corrugated medium  20  or the linerboard  22  can be laminated on the core portion  12 . Referring to  FIG. 4 , it will be seen that the composite material  10   b  can also have only one face sheet  18  with a corrugated medium  20  laminated one face  34   a  of the core portion  12  without departing from the scope of the invention. The other face  34   b  of the core portion  12  can be covered with a linerboard  22  as shown in  FIG. 4  or it can be uncovered. 
     As mentioned earlier, massive application of the honeycomb composite material requires a cost efficient and continuous production, especially for packaging applications to be competitive with the existing products. 
     Referring to  FIG. 5 , there is shown a production line  30  used to manufacture the composite material  10   a  ( FIG. 3 ). The production line  30  has a longitudinal axis  40  and a transversal axis  42  ( FIG. 7 ) which correspond to the longitudinal and transversal axis of the composite material  10   a  manufactured. The faces sheets  18  are provided in webs. Two stacks  44 ,  46  of face sheet webs are provided, each face sheet  18  including a corrugated medium  20  and two linerboards  22  laminated on each side of the corrugated medium  20 . If the face sheets  18  are constituted of a corrugated medium  20  and one linerboard  22  laminated on one side of the corrugated medium  20 , the face sheets  18  are preferably provided in rolls (not shown). Moreover, if the composite material  10   a  includes only one face sheet  18  including the corrugated medium  20 , the production line  30  has only one stack  44  or roll. If the core portion  12  of the composite material  10   a  has one face  34   a  covered with a face sheet  18  including the corrugated medium  20  and the other face  34   b  is covered with a linerboard  22 , a roll  48  ( FIG. 6 ) of linerboard  22  is provided instead of a second stack  46  of face sheet  18 . 
     The production line  30  is continuously fed in face sheets  18  since the face sheets are provided in webs. A new roll or stack  44 ,  46  is supplied to the production line  30  when the face sheet web  18  of a previous roll or stack  44 ,  46  has been totally consumed. The face sheets  18  are carried along the production line  30  with carriers such as driven rolls, as it will be more described in details later. 
     The honeycomb material  14  is provided in a collapsed state to form the core portion  12 . The honeycomb material  14  is previously manufactured with a technology known by those skilled in the art. For example, collapsed blocks  52  of honeycomb material  14  are obtained by printing glue lines on a plurality of flat sheets (not shown). A stack of these sheets is made, the glue is cured, and slices are cut from these blocks  52 . To expand the honeycomb material  14 , the sheets are pulled apart in the direction perpendicular to the planes of the constituent strips, i.e. in the expansion direction, thus expanding into an open cellular state having, usually, an hexagonal cell configuration. However, for the production line  30 , the honeycomb material  14  is provided in a collapsed state since it does not have linerboards  16  laminated thereon to maintain it in the expanded state. Webs of honeycomb material  14  are continuously supplied to the production line  30 . 
     The web of honeycomb material  14  is provided in the collapsed state on pallets (not shown). The pallets carrying honeycomb material  14  are conveyed toward an hydraulic table  56  ( FIGS. 7 and 8 ) with a conveyor  58  ( FIGS. 7 and 8 ). The hydraulic table  56  moves vertically to adjust the height of the pallet. Furthermore, the hydraulic table  56  can tilt to a predetermined angle to facilitate the expansion of the honeycomb material  14 . In a preferred embodiment, the hydraulic table  56  is tilted to a 30-degree angle. 
     The honeycomb material  14  is then expanded on an expanding table  60  ( FIGS. 7 and 8 ). The expanding table  60  is equipped with two expanding rolls  62 , which are preferably scored. Expanding rolls  62  are disposed on each side of the honeycomb material  14 . The height of the expanding rolls  62  can be adjusted according to the thickness of the honeycomb material  14 . The expanding table  60  also includes two curved guides  66  ( FIG. 7 ). While going through the curved guides  66 , the width of the honeycomb material  14  is reduced and, in combination with the expanding rolls  62 , the honeycomb material  14  is expanded. The expanding rolls  62  draw and expand to a predetermined degree the collapsed honeycomb material  14 . The expanding rolls  62  are preferably driven rolls and carry the web of honeycomb material  30  along the production line  30 . Expanding rolls  62  also supply the expanded honeycomb material  14  to a pair of adhesive rolls  68  disposed on each side of the honeycomb material  14 . 
     The expanded honeycomb material  14  is then introduced between the two adhesive rolls  68  where an adhesive is applied on both faces  34   a ,  34   b  of the expanded honeycomb material  14 . Each adhesive roll  68  is continuously supplied in the adhesive to apply homogeneously a predetermined quantity of adhesive on each face  34   a ,  34   b  of the honeycomb material  14 . Any other technique known by those skilled in the art can be used to apply the adhesive on the faces  34   a ,  34   b  of the honeycomb material  14 . If the composite material  10   a  includes only one face sheet  18 , the adhesive is applied on only one face  34   a  of the expanded honeycomb material  14  and the face sheet  18  is applied on the face  34   a  wherein the adhesive has previously been applied. Moreover, one skilled in the art will appreciate that the adhesive can be applied on a face  22  of the face sheets  18 , the face  22  that is in contact with the honeycomb material  14 , without departing from the scope of the invention. However, in that case, the quantity of adhesive required to bond the face sheets  18  on the core portion  12  is more important. 
     The adhesive rolls  68  can be driven rolls to carry the web of honeycomb material  14  or the web of face sheets  18  along the production line  30 . 
     Both face sheets  18  are carried close to the honeycomb material  14  after adhesive rolls  68 , one face sheet  18  on each side of the honeycomb material  14 . The face sheets  18  circulate parallel to the honeycomb material  14 . The face sheets  18  are carried along with a plurality of rolls  50  disposed at various positions (only one is shown). Some of the rolls  50  can be driven rolls. 
     The face sheets  18  are laminated on the honeycomb material  14  with two insertion rolls  80 , one roll  80  disposed on each side of the honeycomb material  14 . As it is seen in  FIG. 5 , each face sheet  18  is inserted between the insertion roll  80  and the honeycomb material  14 . The insertion roll  80  applies a slight pressure on the face sheet  18  and the honeycomb material  14  to create a link between both and produce the composite material  10   a  without excessively compressing any of them. Insertion rolls  80  can also be driven rolls to carry the web of composite material  10   a  along the production line  30 . 
     The composite material  10   a  can then circulate between two heating plates (not shown) wherein the adhesive is heated to activate its adhesive properties. For example, for PVA, the adhesive is heated to approximately 215° C. One heating plate can be disposed on each side of the composite material  10   a . One skilled in the art will appreciate that the heating plates can be replaced by several heating systems and apparatus such as electric plates, steam plates, gas or electric infrared heaters, microwaves, and a warm air flow. 
     Thereafter, the composite material  10   a  goes between two compression conveyors  96  wherein the honeycomb material  14  and the face sheets  18  are maintained together permitting the adhesive to set. The composite material  10   a  is maintained in the compression conveyors  96  until the adhesive is sufficiently dried and an adequate bond is formed between honeycomb material  14  and face sheets  18 . One compression conveyor  96  disposed on each side of the composite material  10   a . Each compression conveyor  96  has a rubber endless belt  98  mounted over a plurality of rolls  100 . The width of the compression conveyors  96  is preferably at least equal to the width of the composite material  10   a  and they are sufficiently long to permit to the adhesive to set. The pressure applied by both two compression conveyors  96  is small in order to provide a composite material  10   a  with a honeycomb material  14  that has not been excessively compressed. However, it is sufficient to maintain both face sheets  18  in continuous contact with the honeycomb material  14  to ensure an adequate adhesion of the composite material  10   a . The compression conveyors can also be carriers that carries the web of composite material  10   a  along the production line  30 . 
     One skilled in the art will appreciate that even if the compression conveyors  96  are used to maintain the honeycomb material  14  in contact with the face sheets  18 , any other appropriate system can be used such as flat presses or a plurality of rolls disposed on each side of the composite material  10   a . The system used to maintain the composite material  10   a  together until the adhesive is set can be cooled down to accelerate the adhesive setting. Infrareds can also be used to accelerate the adhesive setting. 
     Thereafter, the composite material  10   a  is sent to a trim cutter unit  110  wherein the trims of the composite material  10   a  are cut to obtain a composite material  10   a  having a predetermined width. It is followed with a longitudinal cutter unit  112  wherein the composite material  10   a  manufactured is cut longitudinally. If desired, it is also possible to cut grooves on-line to facilitate the folding of the composite material  10   a . In a groove cutter unit  114 , a saw (not shown) cuts one face sheet  18  along a predetermined length and a wheel (not shown) is used to bend the composite material  10   a  at a predetermined angle, for instance 90°. It is followed with a transversal cutter unit  116  wherein pieces of the composite material  10   a  having a predetermined length are produced by cutting transversally the composite material  10   a  manufactured. As one skilled in the art will appreciate, the composite material  10   a  can be cut on-line or off-line and the order of the cutting operations (trim cutter unit  110 , longitudinal cutter unit  112 , groove cutter unit  114 , and transversal cutter unit  116 ) can be interchanged. 
     Referring to  FIG. 6 , it will be seen another embodiment of a production line  130  used to manufacture the composite material  10   b  ( FIG. 4 ) with a hot-melt adhesive process. A stack  44  of face sheet  18 , having a corrugated medium  20  and two linerboards  22  laminated on each side of the corrugated medium  20 , is provided to cover a first face  34   a  of the honeycomb material  14 . A roll  48  of linerboard  22  is also provided to cover the opposite face  34   b  of the honeycomb material  14 . As for the production line  30  ( FIG. 5 ), the face sheet  18  and the linerboard  22  are fed to the production line  130  with driven rolls. Each of the face sheet  18  and the linerboard  22  are provided on one particular side of the honeycomb material  14 . The honeycomb material  14  is provided In a collapsed state to form the core portion  12 . The honeycomb material  14  is supplied, expanded, and the adhesive is applied in a similar manner than for the production line  30 . However, the adhesive applied is an hot melt adhesive that does not need to be activated with heat to have adhesive properties. The hot melt adhesive is applied on both faces  34   a ,  34   b  of the expanded honeycomb material  14 . The face sheet  18  and the linerboard  22  are applied on the expanded honeycomb material  14  similarly as for the production line  30  of  FIG. 5 . Two compression conveyors  96  are used to maintain the face sheet  18  and the linerboard  22  in contact with the honeycomb material  14  during only few seconds since the hot melt adhesive dries rapidly. Therefore, the length of the compression conveyors  96  of production line  130  is shorter than the length of the compression conveyors  96  of production line  30 . 
     Thereafter, the composite material  10   b  is sent to trim cutter unit  110 , followed with the longitudinal cutter unit  112 , and the groove cutter unit  114  where a saw cuts the face sheet  18  along a predetermined length and a wheel is used to bend the composite material  10   b  at a predetermined angle, for instance 90°. Finally, the composite material  10   b  is sent to the transversal cutter unit  116 . As mentioned earlier, one skilled in the art will appreciate that the composite material  10   a  can be cut on-line or off-line and the order of the cutting operations (trim cutter unit  110 , longitudinal cutter unit  112 , groove cutter unit  114 , and transversal cutter unit  116 ) can be interchanged. 
     Referring simultaneously to  FIGS. 7 and 8 , there is shown an apparatus  230  for manufacturing the composite material  10   b  ( FIG. 4 ) with the production line  30 . A stack  44  of face sheet  18 , having a corrugated medium  20  and two linerboards  22  laminated on each side of the corrugated medium  20 , is provided to cover a first face  34   a  of the honeycomb material. A roll  48  of linerboard  22  is also provided to cover the opposite face  34   b  of the honeycomb material (not shown). The face sheet  18  and the linerboard  22  are fed to the production line  30  with driven rolls. Each of the face sheet  18  and the linerboard  22  are provided on one particular side of the honeycomb material. 
     As for the production lines  30  and  130 , the honeycomb material is provided in the collapsed state on pallets that are conveyed toward the hydraulic table  56  with the conveyor  58 . The honeycomb material is then expanded on the expanding table  60 . The expanding table  60  is equipped with two expanding rolls  62  disposed on each side of the honeycomb material and two curved guides  66 . The expanding table  60  draws and expands to a predetermined degree the collapsed honeycomb material. Expanding rolls  62  also supply the expanded honeycomb material to a pair of adhesive rolls  68  disposed on each side of the honeycomb material. The adhesive rolls  68  apply the adhesive on both faces  34   a ,  34   b  of the expanded honeycomb material. 
     The face sheet  18  and the linerboard  22  are carried close to the honeycomb material after adhesive rolls  68 . The face sheet  18  and the linerboard  22  circulate parallel to the honeycomb material. The face sheet  18  and the linerboard  22  are carried along with a plurality of rolls  50  disposed at various positions (only one is shown). Some of the rolls  50  can be driven rolls. 
     The face sheet  18  and the linerboard  22  are laminated on the honeycomb material with two Insertion rolls  80 , one roll  80  disposed on each side of the honeycomb material. As it is seen in  FIG. 5 , the face sheet  18  and the linerboard  22  are inserted between a respective insertion roll  80  and the honeycomb material  14 . The composite material  10   a  can then circulate between two heating plates wherein the adhesive is heated to activate its adhesive properties. 
     Thereafter, the composite material  10   a  goes between two compression conveyors  96  wherein the honeycomb material and the face sheets  18  are maintained together permitting the adhesive to set. One compression conveyor  96  disposed on each side of the composite material  10   a . Each compression conveyor  96  has a rubber endless belt  98  mounted over a plurality of rolls  100 . Then, the composite material  10   b  is sent to cutter units (not shown) described above. 
     The honeycomb material  14  can be corrugated honeycomb without departing from the scope of the invention. Furthermore, one skilled in the art will understand that the adhesive can be applied on the face sheets  18  without departing from the scope of the invention. 
     The composite material produced with either the hot melt production line  130  or the conventional production line  30  can consist in any combination of at least one face sheet  18  having at least one corrugated medium  20  laminated on a honeycomb material  14 . 
     One skilled in the art will understand that any number of linerboards  16 ,  22  or face sheets  18  can be laminated on the composite material  10   a ,  10   b  without departing from the scope of the invention. 
     The composite material  10   a ,  10   b  can be used for packaging applications wherein at least a portion of a container as shown in  FIG. 7  is made of the composite material  10   a ,  10   b.    
     The core portion  12 , the face sheets  18 , and the linerboard  22  are preferably made from material which may be readily recycled using commercially available technology such as wood fiber based materials (cardboard, kraft paper, recycled paper, medium, chipboard, bleached or not, and the like). The material can be impregnated with a resin to improve its resistance to water, grease or fire, its gas and vapor barrier properties, its non-slip properties, and the like. 
     The choice of the adhesive to join together the various components of the composite material  10   a ,  10   b  can also be made on the basis of recyclability. The adhesive must ensure a good adhesion of the core portion  12  and the face sheets  18  or the linerboard  22 , remain on the top of the honeycomb material, and bond very rapidly. Adhesives such as polyvinyl alcohol (PVA), stamp glue, dextrin, and polyurethane can be used to assembly the composite material  10 . Hot melt adhesives such as polyolefin and ethylene vinyl acetate (EVA) can also be used. 
     Preferably, the composite material is wholly recyclable. It can be used as a packaging material due to its high strength for resisting stresses and strains. 
     The embodiments of the invention described above are intended to be exemplary only. For example, a portion or the entirety of the wood fiber based materials forming the composite material can be covered with a metallic foil, such as an aluminum foil, or a polymer, such as polyethylene. The composite material can be used in building applications such as for walls, doors, tableaux, etc. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.