PROCESS FOR MANUFACTURING A HONEYCOMB COMPOSITE MATERIAL

Abstract

The process relates to the continuous production of a web of a composite material, comprising: providing a web of honeycomb material; providing at least one web of face sheet material having a corrugated medium with a first face covered with a linerboard and an exposed second face, including unrolling the face sheet material from a roll; carrying said web of honeycomb material and said at least one web of face sheet material along a production line; and adhesively applying the exposed second face of the 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.

Description

FIELD OF THE INVENTION

The present invention relates to the field of manufacturing composite materials and, more particularly, to a process for manufacturing a honeycomb composite material. The composite material can be used for packaging and building applications, for instance.

BACKGROUND OF THE INVENTION

Safe product delivery requires a strong and efficient packaging material which can hold up under tough conditions. When selecting a packaging material, one typically considers its weight, its recyclability, its mechanical properties, and its cost.

Foam materials are widely used since they are inexpensive and lightweight. However they are typically not recognized as being environmentally friendly. Moreover, sometimes foam materials can generate static electricity when in contact with another object. Most paper honeycomb materials are fully recyclable, lightweight, and inexpensive. Honeycomb materials probably offer the best strength to weight ratio of packaging materials. However, they are characterized by a lower 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 properties can be obtained.

Mass production of packaging materials calls for cost efficient and continuous productions to be competitive with existing products. Furthermore, higher than average mechanical properties are sought, to allow reducing weight and lowering raw material cost.

SUMMARY OF THE INVENTION

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 comprising the steps of: providing at least one web of face sheet material having a corrugated medium with a first face covered with a linerboard and an exposed second face, including unrolling the face sheet material from a roll; carrying said web of honeycomb material and said at least one web of face sheet material along a production line; and adhesively applying the exposed second face of the 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.

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 material such as cardboard, kraft paper, recycled paper, medium, chipboard, bleached or not, and the like, for instance.

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 manually manufactured composite material according to the prior art;

FIG. 2 is an exploded perspective view of the composite material of FIG. 1;

FIG. 3 is an exploded perspective view of a first embodiment of a composite material;

FIG. 4 is an exploded perspective view of a second embodiment of a composite material;

FIG. 5 is a schematic view of an example of a process for manufacturing a composite material in accordance with the first embodiment;

FIG. 6 is a schematic view of an example of a process for manufacturing a composite material in accordance with the second embodiment;

FIG. 7 is a top plan view of an apparatus for manufacturing a composite material; and

FIG. 8 is a side elevation view of the apparatus of FIG. 7.

It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2, a composite material 10 typically used in packaging applications is shown. 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 used 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 has a corrugated medium 20 and two linerboards 22, one laminated on each side of the corrugated medium 20. The composite material 10 has satisfactory mechanical properties for some packaging applications. However, the operation of manually laminating the face sheets 18 on the core portion 12 results in relatively high manufacturing costs, and is known to limit the competitiveness of this product on the market.

Referring to FIG. 3, there is shown an example of honeycomb composite material 10a manufactured by a production line 30 such as shown in FIG. 5. The composite material 10a has a core portion 12 and two face sheets 18 laminated on the core portion 12. In this example, the core portion 12 has a honeycomb material 14 in an expanded state. As opposed to the material shown in FIGS. 1 and 2, the honeycomb material 14 is not covered with linerboards 16 laminated on each side. The core portion 12 has two faces 34a, 34b. In this instance, the cells of the honeycomb material 14 have an hexagonal shape, though any other suitable shape can be used. Each face sheet 18 includes a corrugated medium 20 having a first face 20a with a linerboard 22 laminated thereon, and an exposed second face 20b. In this embodiment, the exposed second face 20b of each face sheet 18 is directly laminated on the honeycomb material 14 forming the core portion 12. Alternately to the embodiment illustrated in FIG. 3, it will be understood that the linerboard covered face 22, of the face sheet material 18, can be directly laminated on the honeycomb material 14, i.e. either face 22 or 20b of the face sheet 18 can be applied to the honeycomb material 14. As can be appreciated, the amount of raw material used is reduced as compared to the amount of raw material used in the composite material 10 shown in FIGS. 1 and 2.

Further, the face sheets 18 can include a linerboard 22 laminated on a single side of the corrugated medium 20, or alternately include a linerboard 22 laminated on each side of the corrugated medium. For example, referring to FIG. 4, the composite material 10b can also have a single face sheet 18 with a corrugated medium 20 applied thereon. The other face 34b of the core portion 12 can be covered with a linerboard 22 or be left uncovered, for example.

Referring to FIG. 5, an example of a production line 30 which can be used to manufacture the composite material 10a (FIG. 3) is shown. The production line 30 has a longitudinal axis 40 and a transversal axis 42 (visible in FIG. 7) which correspond to the longitudinal and transversal axis of the composite material 10a. The faces sheets 18 are provided in webs. Two rolls 44, 46 of face sheet material 18 are provided. In this example, the two rolls are similar. The corrugated medium has a first face covered with a linerboard, and a second face which is left exposed. The absence of a linerboard on the exposed, inner face, of the corrugated medium eases the rolling and unrolling of the face sheets into and from rolls. Thus, when 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 can be provided in rolls.

In the roll, the first face covered with a linerboard can be oriented either radially outwardly, or radially inwardly. Furthermore, either the covered face or the exposed face of the corrugated medium can be applied to the honeycomb material.

Moreover, if the composite material 10a includes only one face sheet 18 including the corrugated medium 20, the production line 30 can have only a single roll 44. If the core portion 12 of the composite material 10a has one face 34a covered with a face sheet 18 including the corrugated medium 20 and the other face 34b is covered with a linerboard 22, a roll 48 (FIG. 6) of linerboard 22 is provided instead of a roll 46 of face sheet 18.

It will be noted that in alternate embodiments, the face sheet material can be provided in a web by unfolding from a stack of folded face sheet material, instead of unrolling from a roll. When provided in a stack, the face sheet material can have a corrugated medium 20 covered by a single linerboard, or covered by linerboards on both sides, for example.

The production line 30 is continuously fed in face sheets 18 since the face sheets are provided in webs. A new roll 44, 46 is supplied to the production line 30 when the face sheet web 18 of a previous roll 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 described in more detail below.

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 can be obtained by printing glue lines on a plurality of flat sheets (not shown). A stack of these sheets can be made, the glue be cured, and slices be 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 34a, 34b 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 34a, 34b 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 34a, 34b of the honeycomb material 14. If the composite material 10a includes only one face sheet 18, the adhesive is applied on only one face 34a of the expanded honeycomb material 14 and the face sheet 18 is applied on the face 34a 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 typically 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 10a without excessively compressing any of them. Insertion rolls 80 can also be driven rolls to carry the web of composite material 10a along the production line 30.

The composite material 10a 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 10a. 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 10a 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 10a 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 10a. 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 10a 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 10a 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 10a. The compression conveyors can also be carriers that carries the web of composite material 10a 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 10a. The system used to maintain the composite material 10a 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 10a is sent to a trim cutter unit 110 wherein the trims of the composite material 10a are cut to obtain a composite material 10a having a predetermined width. It is followed with a longitudinal cutter unit 112 wherein the composite material 10a manufactured is cut longitudinally. If desired, it is also possible to cut grooves on-line to facilitate the folding of the composite material 10a. 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 10a at a predetermined angle, for instance 90°. It is followed with a transversal cutter unit 116 wherein pieces of the composite material 10a having a predetermined length are produced by cutting transversally the composite material 10a manufactured. As one skilled in the art will appreciate, the composite material 10a 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.

A continuous process as described hereinabove typically helps reducing manufacturing costs. The amount of raw material can also be reduced.

Referring to FIG. 6, it will be seen another embodiment of a production line 130 used to manufacture the composite material 10b (FIG. 4) with a hot-melt adhesive process. A roll 44 of face sheet 18, having a corrugated medium 20 and one linerboard 22 laminated on one side of the corrugated medium 20, is provided to cover a first face 34a of the honeycomb material 14. A roll 48 of linerboard 22 is also provided to cover the opposite face 34b of the honeycomb material 14. As for the production line 30 (FIG. 5), in the production line 130 of FIG. 6, the face sheet 18 and the linerboard 22 can be 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. In this second example, the adhesive applied is a hot melt adhesive that does not need to be activated with heat to have adhesive properties. The hot melt adhesive can be applied on both faces 34a, 34b of the expanded honeycomb material 14. The face sheet 18 and the linerboard 22 are then applied on the expanded honeycomb material 14. 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 (FIG. 6) can be shorter than the length of the compression conveyors 96 used in the production line 30 (FIG. 5).

After processing, the composite material 10a, 10b can be sent to a trim cutter unit 110, followed with a longitudinal cutter unit 112, and a 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 10b at a predetermined angle, for instance 90°. Finally, the composite material 10b is sent to a transversal cutter unit 116. As mentioned earlier, one skilled in the art will appreciate that the composite material 10a 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 changed.

Referring to FIGS. 7 and 8, there is shown an apparatus 230 for manufacturing the composite material 10b (FIG. 4), in accordance with the production line 130 schematically depicted in FIG. 6. A roll 44 of face sheet 18, having a corrugated medium 20 and a linerboard laminated on one side of the corrugated medium 20, is provided to cover a first face 34a of the honeycomb material. A roll 48 of linerboard 22 is also provided to cover the opposite face 34b 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 respective 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 34a, 34b 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 10a can then circulate between two heating plates wherein the adhesive is heated to activate its adhesive properties.

Thereafter, the composite material 10a 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 10a. Each compression conveyor 96 has a rubber endless belt 98 mounted over a plurality of rolls 100. Then, the composite material 10b 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 alternately be applied on the face sheets 18.

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 10a, 10b.

The composite material can be used for packaging applications wherein at least a portion of a container is made of the composite material.

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 10a, 10b 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 relatively 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.

Claims

1. A process for a continuous production of a web of a composite material, the process comprising the steps of: providing a web of honeycomb material; providing at least one web of face sheet material having a corrugated medium with a first face covered with a linerboard and an exposed second face, including unrolling the face sheet material from a roll; carrying said web of honeycomb material and said at least one web of face sheet material along a production line; and adhesively applying one of said first face and second face of the 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.

2. A process as claimed in claim 1, further comprising the step of expanding said honeycomb material from a collapsed state to said expanded state while said honeycomb material is being conveyed through the production line.

3. A process as claimed in claim 1, wherein the step of adhesively applying said at least one web of face sheet material to one face of said honeycomb material further comprises applying an adhesive on one of at least one face of said web of honeycomb material and a face of each of said at least one web of face sheet material; laminating said at least one web of face sheet material on said web of honeycomb material, said adhesive being located therebetween; and permitting said adhesive to set to keep said at least one web of face sheet material laminated with said web of honeycomb material.

4. A process as claimed in claim 3, wherein said adhesive is applied on at least one face of said web of honeycomb material.

5. A process as claimed in claim 3, further comprising heating said adhesive.

6. A process as claimed in claim 1, further comprising trimming said web of composite material.

7. A process as claimed in claim 1, further comprising cutting one of said at least one face sheet material of said web of composite material and bending said web of composite material to a predetermined angle.

8. A process as claimed in claim 1, further comprising cutting longitudinally said web of composite material.

9. A process as claimed in claim 1, further comprising cutting transversally said web of composite material.

10. A process as claimed in claim 1, wherein the step of adhesively applying includes adhesively applying the exposed second face of the face sheet material to the honeycomb.

11. A process for a continuous production of a web of a composite material, the process comprising the steps of: unrolling a face sheet material from a roll, the face sheet having a corrugated medium with a first face covered with a linerboard and an exposed second face; carrying said unrolled face sheet material along a production line; expanding a web of honeycomb material into an expanded state; and adhesively applying said face sheet material to the web of honeycomb material in the expanded state.

12. A process as claimed in claim 11, further comprising expanding said honeycomb material from a collapsed state to said expanded state while said honeycomb material is being conveyed through the production line.

13. A process as claimed in claim 11, wherein the step of adhesively applying said at least one web of face sheet material to one face of said honeycomb material further comprises applying an adhesive on one of at least one face of said web of honeycomb material and a face of each of said at least one web of face sheet material; laminating said at least one web of face sheet material on said web of honeycomb material, said adhesive being located therebetween; and permitting said adhesive to set to keep said at least one web of face sheet material laminated with said web of honeycomb material.

14. A process as claimed in claim 13, wherein said adhesive is applied on at least one face of said web of honeycomb material.

15. A process as claimed in claim 13, farther comprising heating said adhesive.

16. A process as claimed in claim 11, further comprising trimming said web of composite material.

17. A process as claimed in claim 11, further comprising cutting one of said at least one face sheet material of said web of composite material and bending said web of composite material to a predetermined angle.

18. A process as claimed in claim 11, further comprising cutting longitudinally said web of composite material.

19. A process as claimed in claim 11, further comprising cutting transversally said web of composite material.

20. A process as claimed in claim 11, wherein the step of adhesively applying includes adhesively applying the exposed second face of the face sheet material to the honeycomb.