A sheet material and method for forming a sheet material

Abstract

A sheet of paper material (100) for use in making a formed, such as a moulded, product (300) is disclosed. The sheet of paper material (100) comprises a plurality of slits (102) therethrough and at least two sets of fold lines (104, 106), about which the sheet is foldable into a pleated configuration. A pleated sheet (400) is also disclosed. Methods are also described for forming a pleated sheet (400) from a sheet of paper material (100) and for forming a moulded product (300) from the pleated sheets are also disclosed. A formed, such as moulded, product (300) is also disclosed.

Description

[0001] A SHEET MATERIAL AND METHOD FOR FORMING A SHEET MATERIAL

[0002] Cross-reference to Related Application

[0003] This application claims priority from Australian Provisional Patent Application No. 2024900520 filed on 28 February 2024, entitled “A SHEET MATERIAL AND METHOD FOR FORMING A SHEET MATERIAL”, the entire contents of which is incorporated herein by reference.

[0004] Field of the Invention

[0005] The invention relates to a sheet of paper material for use in making a formed, such as a moulded, product. The invention also relates to methods of pleating the sheet of paper material and forming a pleated sheet for use in manufacturing a formed, such as a moulded, product, methods for forming a product, such as a moulded product, using the pleated sheet(s), and a formed product, such as moulded, product suitable for use, for example, in packaging.

[0006] Background of the Invention

[0007] When providing formed, such as moulded, products suitable for use in packaging, it is important to ensure that the product has sufficient strength to retain objects and to withstand external forces that are applied thereto.

[0008] In order to assist to achieve this objective, developers often use plastics materials due to the ease with which they can be formed, including moulded, into a desired shape, and the low cost of the materials required. However, the prevalent use of plastics materials for packaging can contribute to environmental issues, as many such materials are non-recyclable and end up in landfill or in oceans and those materials that can be recycled are not recycled to a great extent and also end up in landfill or in oceans, with one outcome being the release of potentially toxic micro-plastic particles upon degradation. Additionally, plastics materials are generally sourced from fossil fuels, which results in a further negative environmental impact. Other developers use paper pulp or other fibre materials when producing packaging. Whilst these packages are generally less environmentally damaging than those utilizing plastics materials, these materials often result in packaging having greater weight and less strength and flexibility.

[0009] The applicant has developed an alternative sheet material and formed, including moulded, product made from the sheet material.

[0010] The above description is not to be taken as an admission of the common general knowledge in Australia or elsewhere.

[0011] Summary of the Invention

[0012] The applicant has invented a sheet of paper material and methods of preparing formed, such as moulded, products from the sheet of paper material.

[0013] The use of the paper material provides an opportunity to reduce environmental impact of formed, such as moulded, products compared to corresponding products made from plastics and other paper pulp products.

[0014] The use of the paper material provides an opportunity to allow for moulded or otherwise formed products to be manufactured at a lower weight than corresponding plastics and other paper pulp products, which may further reduce environmental impact when used as packaging.

[0015] The term “paper material” is understood herein to mean a material manufactured in sheets from the pulp of wood or other fibre material such as fibrous substances, used for writing, drawing, or printing on, or as wrapping material or as a material to form formed, such as moulded, products for use in a range of applications such as a packaging material. Typically, paper material suitable for forming into a moulded product has a grammage of approximately 20gsm to 200gsm, typically 40gsm to 200gsm, although heavier (i.e. thicker) paper could also be used depending on the particular requirements for a moulded product. The term “paper material” includes but is not limited to what is generally described as “paper”. The sheet of paper material of the invention includes a sheet having sets of slits and sets of fold lines that allow the sheet of paper material to be folded about the fold lines into a pleated configuration, i.e. forming a pleated sheet, that is both sturdy and flexible, suitable for use in a mould or other forming option for forming a moulded or otherwise formed product.

[0016] In this regard, the slits in the sheet of paper material allow the pleated sheet to be pressed or otherwise formed into a desired product shape with a reduced risk of tearing during formation.

[0017] In other words, the purpose of the slits is to allow relative movement of the sheet of paper material on opposite sides of the slits to accommodate folding about fold lines and to accommodate relative movement required when a pleated sheet is moulded or otherwise formed into a shaped product.

[0018] The invention provides a sheet of a paper material for use in making a formed product, the sheet comprising: a plurality, such as an array, of slits therethrough; and at least two sets of fold lines, about which the sheet is foldable into a pleated configuration, i.e. forming a pleated sheet.

[0019] In this context, the term “pleated” means that the sheet has a double or multiple fold, which increases the thickness of the sheet material compared with the non-pleated sheet material.

[0020] In some embodiments, the sheet of paper material comprises: a plurality, such as an array, of slits extending at a first angle with respect to a longitudinal axis of the sheet of paper material, the slits including multiple sets of slits, wherein each set of slits is separated longitudinally from each other set of slits; a set of primary fold lines, wherein each primary fold line is separated from another primary fold line by a first distance; a set of secondary fold lines, wherein each secondary fold line is separated from an adjacent primary fold line by a second distance; and wherein the sheet of paper material is foldable in a first direction from a flat plane at each primary fold line and foldable in a second direction from the flat plane, opposite the first direction, at each secondary fold line, such that the sheet of paper material is formable into a pleated configuration.

[0021] The sheet of paper material may be rectangular or, alternatively, any other suitable shape. In embodiments wherein the sheet of paper material is rectangular, the longitudinal axis may be defined as the axis that runs parallel to the longer sides of the sheet. However, the present invention is not limited to this, and alternative longitudinal axes are definable.

[0022] The slits may be straight slits.

[0023] Alternatively, the slits may be curved, or angled or may have any other suitable shape.

[0024] In some embodiments, the sheet of paper material, when formed into the pleated configuration, comprises a plurality of regions with at least three paper layers.

[0025] In some embodiments, the primary fold lines and the secondary fold lines are positioned perpendicularly to the longitudinal axis of the sheet material.

[0026] In some embodiments, the secondary fold lines run parallel to the primary fold lines.

[0027] In some embodiments, the slits in each set of slits are parallel to each other.

[0028] In some embodiments, the slits comprises a first set of slits and a second set of slits.

[0029] In some embodiments, the first set of slits is laterally offset with respect to the second set of slits.

[0030] In some embodiments, each primary fold line is positioned between a first set of slits and a second set of slits

[0031] In some embodiments, each primary fold line runs through a first set of slits or a second set of slits.

[0032] In some embodiments, each primary fold line of the set of primary fold lines and / or each secondary fold line of the set of secondary fold lines is provided with a set of slits oriented in the direction of the fold line, the set of slits extending along the length of the fold line The sheet of paper material, when formed into the pleated configuration, i.e. as a pleated sheet, may comprise any suitable number of layers.

[0033] In some embodiments, the sheet of paper material, when formed into the pleated configuration, i.e. as a pleated sheet, comprises at least three layers across its whole length.

[0034] In some embodiments, the first distance is between 30mm and 50mm.

[0035] In some embodiments, the second distance is between 10mm and 20mm.

[0036] In some embodiments, the first distance is 30mm and the second distance is 10mm.

[0037] In some embodiments, the first distance is 50mm and the second distance is 20mm.

[0038] The primary fold lines and the secondary fold lines may be at any suitable angle(s) from the longitudinal axis of the sheet material.

[0039] In some embodiments, the primary fold lines and the secondary fold lines are positioned at an angle of 15-45° from the longitudinal axis of the sheet. For example, the primary fold lines and the secondary fold lines may be positioned at an angle of approximately 45° from a longitudinal axis of the sheet

[0040] In some embodiments, the sheet of paper material comprises: an array of slits extending at a first angle with respect to the longitudinal axis of the sheet, the array of slits including multiple sets of slits, wherein each set of slits is separated longitudinally from each other set of slits; a set of primary fold lines, a set of secondary fold lines, a set of tertiary fold lines, and a set of quaternary fold lines; wherein the sheet of paper material is foldable about each of the primary, secondary, tertiary and quaternary fold lines, such that the sheet is formable into a box pleat configuration, i.e. forming a box-pleated sheet.

[0041] In some embodiments, the sheet of paper material, when formed into the box pleat configuration, i.e. forming the box-pleated sheet, comprises a plurality of regions with at least three paper layers

[0042] In some embodiments, each primary fold line is separated from a nearest secondary fold line, and each tertiary fold line is separated from a nearest quaternary fold line, by a first distance; each secondary fold line is separated from a nearest tertiary fold line, and each quaternary fold line is separated from a neatest primary fold line, by a second distance; a set of first regions is defined between the quaternary fold lines and the primary fold lines, a set of second regions is defined between the primary fold lines and the secondary fold lines, a set of third regions is defined between the secondary fold lines and the tertiary fold lines, and a set of fourth regions is defined between the tertiary fold lines and the quaternary fold lines; and the first regions are foldable in a first direction about the primary fold lines, the second regions are foldable in a second direction about the secondary fold lines, the third regions are foldable in the second direction about the tertiary fold lines, and the fourth regions are foldable in the first direction about the quaternary fold lines, such that the sheet is formable into the box pleat configuration, where the first direction is opposite the second direction.

[0043] In some embodiments, the second distance is approximately double the first distance.

[0044] The invention also provides a pleated sheet comprising a sheet of paper material as described above folded along each fold line of the sets of fold lines to form the pleated configuration.

[0045] The invention also provides a pleated sheet comprising a sheet of paper material as described above folded in a first direction from a flat plane at each primary fold line and folded in a second direction from a flat plane at each secondary fold line to form the pleated configuration. This is a pleated sheet with a “flat pleat” arrangement.

[0046] The invention also provides a pleated sheet comprising a sheet of paper material as described above, wherein: the first regions of the sheet are folded in the first direction about the primary fold lines; the second regions of the sheet are folded in the second direction about the secondary fold lines; the third regions of the sheet are folded in the second direction about the tertiary fold lines; the fourth regions of the sheet are folded in the first direction about the quaternary fold lines to form the box pleat configuration. This is a pleated sheet with a “box pleat” arrangement.

[0047] In some embodiments, the pleated sheet comprises a plurality of regions with at least three paper layers. In some embodiments, the pleated sheet comprises at least three paper layers across its whole length.

[0048] In some embodiments, a barrier layer is applied to at least one surface of the pleated sheet.

[0049] In some embodiments, selected regions of the pleated sheet are reinforced to prevent unfolding or opening of the pleats, wherein said reinforced regions comprise one or more of: adhered together layers of the pleated sheet at the selected regions; embossed layers of the pleated sheet at the selected regions, such that the layers are frictionally engaged with one another; punched and folded layers of the pleated sheet at selected regions, such that the layers are frictionally engaged with one another.

[0050] In some embodiments, the pleated sheet comprises a central fold line located approximately equidistant from each end of the sheet, with the pleated sheet being foldable about the central fold line such that the pleated sheet is formable into a folded configuration in which the pleated sheet comprises a plurality of regions having at least six paper layers.

[0051] In some embodiments, the pleated sheet, when in the folded configuration, comprises a first surface and a second surface, each surface comprising primary and secondary fold lines that are opposed at an angle of approximately 90° from the primary and secondary fold lines of the other surface.

[0052] The invention also provides a stacked pleated sheet comprising at least two pleated sheets as described above, wherein at least a first pleated sheet is arranged on top of a second pleated sheet, such that the stacked pleated sheet comprises a plurality of regions with at least six layers.

[0053] The invention also provides a formed, such as a moulded product comprising a selected number of the above-described sheet of paper material in the pleated configuration.

[0054] The invention also provides a formed, such as a moulded product, comprising the pleated sheet as described above. The formed, such as moulded product, may be a packaging product, such as a tray for holding biscuits or other food products.

[0055] The invention also provides a method of forming a pleated sheet from the above-described sheet of paper material, comprising: (a) passing the sheet of paper material having a selected length through a slitted and forming the sets of slits; (b) forming the primary fold lines and the secondary fold lines sequentially; (c) folding the sheet of paper material in a first direction about each primary fold line; and (d) folding the sheet of paper material in a second direction about each secondary fold line to form the pleated sheet having a plurality of regions with at least three paper layers.

[0056] The above-described method provides a pleated sheet in a “flat pleat” configuration.

[0057] The invention also provides an alternative method of forming the pleated sheet, comprising: (a) passing the sheet of paper material having a selected length through a slitter forming the sets of slits; (b) forming the primary fold lines, secondary fold lines, tertiary fold lines and quaternary fold lines sequentially; (c) folding the sheet of paper material in the first direction about the primary fold lines; (d) folding the sheet of paper material in the second direction about the secondary fold lines; (e) folding the sheet of paper material in the second direction about the tertiary fold lines; and (f) folding the sheet of paper material in the first direction about the quaternary fold lines, to form the pleated sheet having a plurality of regions with at least three paper layers.

[0058] The above-described method provides a pleated sheet in a “box pleat” configuration.

[0059] The invention also provides a method of forming a pleated sheet that can be formed into a folded configuration further, comprising: (a) cutting the pleated sheet to have a selected length from a pleated sheet of a paper material; (b) forming a central fold line in the pleated sheet, the central fold line located approximately equidistant from each end of the pleated sheet; and (c) forming a further fold along the central fold line so that the pleated sheet in the folded configuration has a plurality of regions with at least six layers.

[0060] The invention also provides a method of forming a stacked sheet configuration, comprising: (a) cutting multiple pleated sheets, each having a selected length; and (b) stacking a first pleated sheet on top of a second pleated sheet, to provide the stacked pleated sheet having a plurality of regions with at least six layers.

[0061] The invention also provides a method for forming a moulded product using a pleated sheet as described above, the method comprising: (a) forming the pleated sheet into the folded configuration; (b) applying an adhesive to at least one surface of the pleated sheet in the folded configuration; (c) pressing the pleated sheet in the folded configuration into a mould and heating the paper material to a selected temperature for a selected period of time; and (d) removing a moulded product from the mould.

[0062] In some embodiments, the method comprises applying the adhesive between a plurality of folds of the pleated sheet in the folded configuration.

[0063] The invention also provides a method for forming a moulded product using folded and preglued pleated sheets of a paper material, the method comprising: (a) forming pleated sheets in a folded or stacked configuration according to the above-described methods, wherein the folded or stacked pleated sheets comprise an adhesive substance on at least one surface; (b) activating the adhesive; (c) pressing the pleated sheets into a mould and heating the pleated sheets to a selected temperature for a selected period of time to form a moulded product; and (d) removing the moulded product from the mould.

[0064] In some embodiments, the step of activating the adhesive comprises applying:(a) moisture to the pleated sheets when the adhesive is a moisture-activated adhesive; or (b) heat to the adhesive when the adhesive is a heat-activated adhesive; or (c) light to the adhesive when the adhesive is a light-activated adhesive.

[0065] Brief Description of the Drawings

[0066] By way of example only, specific embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0067] Figure l is a top view of a first embodiment of a sheet of paper material in accordance with the present invention,

[0068] Figure 2a is a perspective view of the sheet of Figure 1 in a pleated (flat pleat) configuration, forming an embodiment of a pleated sheet in accordance with the invention, Figure 2b is a perspective view of the sheet of Figure 1 in an alternative pleated (flat pleat) configuration, forming another embodiment of a pleated sheet in accordance with the invention,

[0069] Figure 2c is a perspective view of the sheet of Figure 1 in another alternative pleated (flat pleat) configuration, forming another embodiment of a pleated sheet in accordance with the invention,

[0070] Figure 3 is a top view of the sheet of Figure 1 in a pleated configuration, forming an embodiment of a pleated sheet in accordance with the invention,

[0071] Figure 4 is a partial perspective view of a second embodiment of sheet of paper material in accordance with the present invention, showing the sheet in a pleated (box pleat) configuration,

[0072] Figure 5 is a plan view of the sheet of Figure 4 in a non-pleated configuration,

[0073] Figure 6 is a perspective view of an embodiment of a moulded product formed using a sheet of paper material in accordance with an embodiment of the present invention,

[0074] Figure 7 is a top view of an alternative slit arrangement, in which adjacent slits in the same set of slits are non-parallel,

[0075] Figure 8a is a top view of an alternative slit arrangement, in which the slits have a curved shape,

[0076] Figure 8b is a top view of an alternative slit arrangement, in which the slits have an angled shape,

[0077] Figure 9a is an enlarged top view of the sheet of paper material of Figure 1, in which adjacent sets of slits are delineated by primary fold lines,

[0078] Figure 9b is a top view of a third embodiment of a sheet of paper material, in which adjacent sets of slits are not delineated by primary fold lines,

[0079] Figure 10 is a top view of a fourth embodiment of a sheet of paper material, wherein primary fold lines and secondary fold lines are non-parallel,

[0080] Figure 11 is a schematic diagram showing an embodiment of a method for pleating a sheet of paper material using a blade pleating machine in accordance with the present invention,

[0081] Figure 12 is a diagram showing an embodiment of a stacked pleated sheet formed from lengths of pleated sheets,

[0082] Figure 13a is a top view of the sheet of paper material of Figure 1, showing slits extending along first and second fold lines,

[0083] Figure 13b is an expanded view of the sheet of Figure 13a, Figure 14 is a perspective view of the sheet of paper material of Figure 1 in a partially pleated configuration,

[0084] Figure 15a is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including reinforced edges,

[0085] Figure 15b is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including reinforced edges and reinforced strips, extending perpendicular to the reinforced edges,

[0086] Figure 15c is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including reinforced regions having different shapes,

[0087] Figure 15d is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including a reinforced (rectangular) grid, Figure 15e is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including reinforced (embossed) edges, Figure 15f is a top view of an embodiment of a pleated sheet in accordance with the invention formed from a sheet of paper material, including reinforced (punched) edges, Figure 15g is an enlarged view of a lateral edge of an embodiment of a pleated sheet in accordance with the invention, illustrating a V-shaped punched section, and

[0088] Figure 15h is an enlarged view of a lateral edge of an embodiment of a pleated sheet in accordance with the invention, illustrating a H-shaped punched section.

[0089] Detailed Description of Selected Embodiments

[0090] In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description.

[0091] The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised, and other changes may be made without departing from the spirit or scope of the subject matter presented.

[0092] It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure.

[0093] One embodiment of a sheet material for use in a formed product is shown in Figure 1.

[0094] The sheet 100 shown in Figure 1 is an elongate sheet of paper material having a rectangular shape.

[0095] The sheet 100 is a discrete piece of material, typically cut from a continuous roll of paper material. The continuous roll of paper material may be provided with hole-punched or embossed side edges.

[0096] The sheet 100 is rectilinear, with parallel sides and parallel ends, but may be any suitable shape.

[0097] The sheet 100 comprises a plurality of sets of parallel slits 102 therethrough, formed at an acute angle a to a longitudinal axis L of the sheet 100, as shown in Figure 1. In the embodiment shown in Figure 1, the angle a of the slit is around 11°, although other possible slit angles are contemplated. It is alternatively envisaged that the slits in a set of slits may be positioned in a non-parallel arrangement (for example, adjacent slits may be positioned in a symmetric arrangement, i.e. with a line of symmetry S running between adjacent slits, as shown in Figure 7).

[0098] The slits 102 can be formed using a CNC paper cutter, or other laser cutting machines. However, other cutting techniques may be utilised if necessary. The means for forming slits 102 in the sheet 100 may be referred to more generally as cutters or slitters.

[0099] In the embodiment of Figure 1, the slits 102 are straight slits. The invention is not confined to straight slits 102 and extends to curved, angled or any other suitable shaped slits. An example of a curved slit arrangement is shown in Figure 8a, and an example of an angled slit arrangement is shown in Figure 8b.

[0100] In addition, the slits in a set of slits 102 are the same length. The invention is not confined to such equal -length slits. In addition, the slits in each set of slits 102 are the same length. The invention is not confined to this arrangement, and the slits in one set of slits 102 may be one length and the slits in another set of slits 102 may be another length.

[0101] In addition, each set of slits 102 is laterally offset from a subsequent set of slits (i.e. the slits do not continue in the same line or path longitudinally). This offset slit configuration means that the sheet material is more resistant to tearing. It is alternatively envisaged that a nonoffset slit configuration can be utilised, depending on the particular materials and slit dimensions used.

[0102] As shown in Figure 1, the sheet 100 has a plurality of primary fold lines 104. The primary fold lines 104 extend across a width of the sheet material 100 perpendicularly to the slits 102. In this embodiment, the primary fold lines 104 thereby delineate each set of slits 102a from the subsequent set of slits 102b, 102c, etc, as shown in Figure 9a. However, other embodiments may include primary fold lines that run through one of more sets of slits, depending on the particular slit pattern used. One example of an alternative embodiment is shown in Figure 9b, which shows the primary fold lines 104 running through both a first set of slits 102a and a subsequent second set of slits 102b.

[0103] As shown in Figure 1, the sheet 100 also has a plurality of secondary fold lines 106, with each secondary fold line 106 being positioned between a pair of primary fold lines 104. The secondary fold lines 106 are positioned parallel to the primary fold lines 104. The secondary fold lines 106 run through one of more sets of slits.

[0104] Alternatively, in other embodiments the primary fold lines 104 and the secondary fold lines 106 may be non-parallel. An example of such an arrangement is shown in Figure 10.

[0105] As shown in Figures 13a and 13b, the primary fold lines 104 and the secondary fold lines 106 have a plurality of slits 110, which are oriented in the direction of the fold lines 104, 106 and extend along the length of the fold lines 104, 106. In other embodiments, the slits 110 may extend only along part of the length of the fold lines 104, 106. Slits 110 may provide flexibility during the formation of a product using the sheet 100, and may assist with folding the material about the fold lines 104, 106 when forming a pleated configuration. Figures 13a and 13b show that each of the primary fold lines 104 and the secondary fold lines 106 have a plurality of slits 110. However, it is alternatively envisaged that only the primary fold lines 104 have slits 110 and the secondary fold lines 106 remain fully intact, or vice versa. Alternatively, a sub-set of the primary fold lines 104 and / or secondary fold lines 106 may have slits 110, whilst other primary or secondary fold lines 104, 106 may remain fully intact.

[0106] The primary fold lines 104 and the secondary fold lines 106 may be at an angle of around 45° from the longitudinal axis L of the sheet 100. Alternatively, the primary fold lines 104 and the secondary fold lines 106 may be at an angle of around 15°, 30°, 60°, or 75° from the longitudinal axis L of the sheet 100, depending on the specific requirements for particular paper materials (and final products formed therefrom). It is also envisaged that any angle from 0° (i.e. fold lines being perpendicular to the longitudinal axis L) to 90° (i.e. fold lines being parallel to the longitudinal axis L) could be utilised, if required.

[0107] Each primary fold line 104 is separated from the subsequent primary fold line 104 by a distance Di, which is consistent along the length of the sheet 100. Each primary fold line 104 is separated from the nearest secondary fold line 106 by a distance D2.

[0108] In one embodiment, the distance Di between adjacent primary fold lines 104 is 30mm, and the distance D2 between the primary fold lines 104 and the nearest secondary fold lines 106 is 10mm. In an alternative, although not the only other possible, embodiment, the distance Di is 50mm and the distance D2 is 20mm.

[0109] The sheet 100 is formed into a pleated configuration (thereby forming a pleated sheet) by first forming creases at each of the primary fold lines 104 and secondary fold lines 106. The sheet 100 is then folded tightly in a first direction from the flat plane shown in Figure 1 about each primary fold line 104 and folded tightly in a second direction from what was the flat plane, opposite to the first direction, about each secondary fold line 106. The folding is completed sequentially along the length of the sheet 100 (i.e., a first fold is followed by a second fold, followed by another first fold, and so on). This folding process forms the sheet material into a pleated sheet having a flat pleat (Z-shaped) arrangement shown in Figure 2. The pleated sheet comprises a plurality of sections having a triple-layered arrangement (i.e. three layers of paper folded on top of each other, such that the thickness of a pleated section is three times as thick as the paper material itself). The distances Di and D2 are selected such that, when the sheet 100 is formed into the pleated configuration, the pleated sheet has a triple-layered arrangement across its whole extent (i.e., without gaps between pleats that result in a single-layered section), as shown in Figure 2b.

[0110] In the embodiments of Figures 1 and 2b, the distances Di and D2 are chosen to minimise the amount of material required to form a triple-layered pleated configuration across the whole extent of the pleated sheet. In other embodiments, the distances Di and D2 may be selected to provide a pleated sheet comprising sections having a single layer (i.e., sections with no overlapping) as shown in Figure 2a, or to provide a pleated sheet comprising sections having five layers, as shown in Figure 2c.

[0111] To form the pleated sheet from the sheet 100, the material is unrolled from a continuous roll and passed through a CNC paper cutter (or other suitable cutting means) to form slits 102. The sheet 100 subsequently passes through a tool for applying a primary fold line 104 between each set 102a-102n of slits, and through a tool for applying a secondary fold line 106 at a distance D2 from each primary fold line 104. In some embodiments, the tools apply a crease at each of the primary 104 and secondary fold lines 106, after which the creases are formed into tight folds by additional machinery, or manually by a user. The sheet 100, after tight folding, is formed into a pleated sheet. It is also envisaged that application of the primary fold lines 104 and secondary fold lines 106 and subsequent tight folding can be achieved manually to form the pleated sheet.

[0112] The pleated sheet described above may be formed using known blade pleating machines, or knife pleating machines. This involves passing sheet 100 through the blade pleating machine such that an upper blade (or knife) and a lower blade (or knife) are moved relative to one another to form, in sequence, a primary fold line, a secondary fold line, a further primary fold line, a further secondary fold line, and so on. An example of this method is shown in Figure 11. This allows the sheet 100 to be formed into a pleated sheet without first applying creases, and removes the requirement for additional machinery, or manual intervention. In one embodiment, in which the primary and secondary fold lines 104, 106 are perpendicular to the slits 102, the slits 102 are formed at an angle of 15° to the longitudinal axis L of the sheet 100 (and, for a rectangular sheet, the edge of the sheet material). Formation of the pleated sheet as described above involves the sheet 100 being folded back onto itself twice, which results in an angle of 45° between the slits 102 and the edge of the pleated sheet and, consequently, an angle of 45° between the pleats and the edge of the pleated sheet, as shown in Figure 14. When the pleated sheet is provided in a folded configuration, as described below, this results in an angle of 90° between pleat lines on one surface of the folded pleated sheet and pleat lines on the opposite surface of the folded pleated sheet.

[0113] Alternatively, in an embodiment in which the slits 102 are formed at an angle of 10° to the longitudinal axis L of the sheet 100, formation of the pleated sheet results in an angle of 30° between the slits 102 and the edge of the pleated sheet (and a 60° angle between the pleats and the edge of the pleated sheet). The pleated sheet may be provided in a stacked configuration, as described below, using three pieces of pleated sheet material such that a triangular pattern is formed with a 60° angle between pleat lines in adjacent pieces of sheet material.

[0114] After a desired length of sheet 100 has been processed and formed into a pleated sheet, a final fold may be applied about a central fold line 108. The central fold line 108 is typically located equidistant from each end of the length of pleated sheet, such that the pleated sheet may be folded over the central fold line 108 to form a further folded configuration having half the length of the pleated sheet and double the thickness of the pleated sheet (i.e., six layers of paper on top of one another, providing a thickness six times that of the unpleated and unfolded sheet material).

[0115] In this folded configuration, the pleated sheet is provided with a first surface and a second surface having fold lines that are opposed at an approximately 90° angle to one another. This may improve the stability of the material and may prevent unwanted tearing during formation of products.

[0116] As an alternative to folding the pleated sheet, it is also envisaged that multiple pleated sheets (e.g. two pleated sheets) may be placed one on top of another, to achieve the double thickness (i.e. six layers of paper on top of one another, or a thickness six times that of the unpleated and unfolded sheet material) in a stacked arrangement.

[0117] In some embodiments of the invention, when forming the pleated sheet from the sheet 100, the pleated sheet has one surface comprising loose pleats and one surface comprising rigid pleats, which are more tightly folded than the loose pleats In alternative arrangements in which multiple pleated sheets are placed one on top of another, the stacked arrangement may be such that each outward facing surface comprises rigid pleats, or each outward facing surface comprises loose pleats, or one outward facing surface comprises rigid pleats and the other outward facing surface comprises loose pleats. Examples of these stacked configurations are shown in Figure 12, with R representing a rigid pleat surface and L representing a loose pleat surface.

[0118] A second embodiment of a sheet of paper material for use in a formed product is shown in Figures 4 and 5. The construction of the sheet 200 is similar to that of sheet 100, comprising an elongate sheet of paper material having a rectangular shape, the sheet 200 comprising a set of slits 202 therethrough, formed at an acute angle a to the longitudinal axis L of the sheet 200. In a preferred embodiment, the angle a of the slit is around 11°, although other possible slit angles are contemplated.

[0119] The sheet 200 is provided with a plurality of primary fold lines 204 that extend across the width of the sheet 200.

[0120] As shown in Figures 4 and 5, the sheet 200 is further provided with secondary fold lines 206, tertiary fold lines 208 and quaternary fold lines 210, separated from and positioned parallel to the primary fold lines 204 (and thus, perpendicular to the slits 202). These fold lines repeat sequentially along the length of the sheet 200. As for sheet 100 described above, the primary, secondary, tertiary and quaternary fold lines 204, 206, 208, 210, in some embodiments, have slits that are oriented in the direction of the fold lines 204, 206, 208, 210 and extend along the length of the fold lines, to provide flexibility during the formation of a product and to assist with forming a pleated configuration. Alternatively, in other embodiments, the primary fold lines 204 and / or the secondary fold lines 206 and / or the tertiary fold lines 208 and / or the quaternary fold lines 210 may be nonparallel with respect to at least one other set of fold lines.

[0121] Each primary fold line 204 is separated from the subsequent secondary fold line 206 by a distance D Each secondary fold line 206 is separated from the subsequent tertiary fold line 208 by a distance D2’. Each tertiary fold line 208 is separated from the subsequent quaternary fold line 210 by distance Df. Each quaternary fold line 210 is separated from the subsequent primary fold line 204 by distance D2’.

[0122] The fold lines 204, 206, 208, 210 may be provided at an angle of around 45° from the longitudinal axis L of the sheet 200. Alternatively, the primary fold lines 204 and the secondary fold lines 206 may be provided at an angle of around 15°, 30°, 60°, or 75° from the longitudinal axis L of the sheet 200, depending on the specific requirements for particular paper materials (and final products formed therefrom). It is also envisaged that any angle from 0° (i.e. fold lines being perpendicular to the longitudinal axis L) to 90° (i.e. fold lines being parallel to the longitudinal axis L) could be utilised, if required.

[0123] In one embodiment, the distance Df is half the distance of D2’, such that the sheet 200 can be arranged in a box pleat configuration with no overlapping of folds, as shown in Figure 4. For example, the distance Df may be 20mm and the distance D2’ may be 40mm.

[0124] The sheet 200 can be formed into a box pleat configuration, forming an embodiment of a pleated sheet of the invention, by first forming creases at each of the primary, secondary, tertiary and quaternary fold lines. This results in the formation of first, second, third and fourth regions (shown as regions A, B, C and D in Figure 5) between the sets of fold lines. The first regions (A) are defined between the quaternary fold lines and the primary fold lines, the second regions (B) are defined between the primary fold lines and the secondary fold lines, the third regions (C) are defined between the secondary fold lines and the tertiary fold lines, and the fourth regions (D) are defined between the tertiary fold lines and the quaternary fold lines.

[0125] The creased material is then arranged into a box pleat configuration by folding region A in a first (e.g. anti-clockwise) direction about the primary fold lines, folding region B in a second (e.g. clockwise) direction about the secondary fold lines, folding region C in the second direction about the tertiary fold lines, and folding region D in the first direction about the quaternary fold lines

[0126] The resulting box pleat configuration, i.e. pleated sheet, thus comprises a triple-layered pleated sheet over the whole extent of the sheet material 200, due to the relationship between distances D and D2’. In other embodiments, the distances Df and D2’ may be selected to provide a pleated sheet comprising sections having a single layer (i.e. sections with no overlapping), or to provide a pleated sheet comprising sections having five layers.

[0127] To form the pleated sheet from the sheet 200, the sheet 200 is unrolled from a continuous roll and passed through a CNC paper cutter (or other suitable cutting means) to form slits 202. The sheet 200 subsequently passes through a tool for forming primary fold lines 204, secondary fold lines 206, tertiary fold lines 208 and quaternary fold lines 210, with separation distances D and D2’ as described above. In some embodiments, the tools may form a crease at each of the fold lines 204, 206, 208, 210, after which the creases are formed into tight folds by additional machinery, or manually by a user. The sheet 200, after tight folding, is formed into a pleated sheet. It is also envisaged that application of the fold lines 204, 206, 208, 210 and subsequent tight folding can be achieved manually to form the pleated sheet.

[0128] As described above with respect to sheet 100, it is alternatively envisaged that the box pleat configuration could be achieved by passing the sheet 200 through a blade pleating machine.

[0129] After a desired length of sheet 200 has been processed and formed into a pleated sheet, a final fold may be applied around a central fold line. The central fold line is preferably located equidistant from each end of the length of pleated sheet, such that the pleated sheet may be folded over the central fold line to form a further folded configuration having half the length of the pleated sheet and double the thickness (i.e., six layers).

[0130] As for the flat pleated sheet formed from the sheet 100, it is envisaged that the box pleated sheet formed from the sheet 200 may result in one surface of the pleated sheet comprising loose pleats and the other surface comprising rigid pleats, which are more tightly folded than the loose pleats. As described above for the sheet 100, it is envisaged that the pleated sheet formed from sheet 200 could be provided in a layered arrangement. In this folded configuration, the pleated sheet formed from sheet 200 is provided with a first surface and a second surface having fold lines that are opposed at an approximately 90° angle to one another. This may improve the stability of the material and may prevent unwanted tearing during formation of products.

[0131] It is envisaged that for each of the embodiments described above, a pleat configuration may be applied such that the sheet material has a thickness of greater than three layers.

[0132] In some embodiments, the sheet material is Glassine paper having a grammage of around 40gsm. It is envisaged that the sheets may alternatively be formed from other cellulose- containing materials, suitable for formation in pleated and folded configurations.

[0133] For each of the embodiments described above, the pleated sheet formed from sheets 100, 200 (in the original, unfolded configuration, or in the final folded configuration) can be used to form a moulded or otherwise formed product, suitable for use in packaging.

[0134] The embodiments of the pleated sheets shown in Figures 1-5 are designed to be formed into a desired shape, using known male-female moulds. The pleated sheets may alternatively be formed into a desired shape by using a female mould part in combination with a flexible bladder (i.e. bladder moulding), or by using a mould part in combination with another material that contacts the opposing side of the pleated sheet to the mould part.

[0135] An example of a moulded or otherwise formed product formed using pleated sheets described above is shown in Figure 6.

[0136] The product 300 shown in Figure 6 is a tray that is suitable for use in packaging biscuits. The invention is not confined to manufacturing such trays.

[0137] One method of forming the product 300 comprises applying an adhesive to one surface of the pleated sheet formed from the sheet 100, 200, when the pleated sheet is in its folded configuration. In some embodiments, an adhesive is applied between individual folds of the folded pleated sheet in order to secure the folds in position and to achieve a flat surface. The adhesive may comprise a polyvinyl acetate solution, or any other compounds, solutions or materials that provide suitable adhesion.

[0138] After applying the adhesive, the pleated sheet (in its folded configuration) is placed over one part of a mould (e.g., a male-female mould) or other suitable forming apparatus. The accompanying part of the mould is then placed over the pleated sheet and the mould parts pressed together to firmly receive the pleated sheet in the mould. The pressure applied to the mould can be selected by a user depending on the specific requirements for the paper material used. The mould is then heated to a desired temperature for a selected period of time, with the specific temperature and period selected to allow the adhesive to sufficiently cure or set. After the adhesive is set, the mould is removed to leave a formed, rigid product.

[0139] For Glassine paper having a grammage of 40gsm and provided in a folded configuration having 6 layers as described above, a solution of polyvinyl acetate and water in a 1 : 1 ratio may be applied to the paper, and the treated paper may be heated to 130°C and pressed at 10,000kg to form a moulded paper product.

[0140] The provision of folds and slits provides flexibility and stability for the pleated sheet that allows the pleated sheet to be formed and pressed into a desired shape without causing the material to tear.

[0141] The moulded product may be processed further to remove excess material outside of the desired mould shape.

[0142] In some embodiments, the sheets 100, 200 may instead be ‘pre-glued’, by applying an adhesive to one or both surfaces of the sheet (thus avoiding the need to apply adhesive after folding). The adhesive may be applied to the sheets 100, 200 by spraying, brushing, or printing onto the (unpleated and unfolded) sheets 100, 200. Alternatively, the adhesive may be formed as an adhesive film layer that can be applied to the sheets 100, 200. This adhesive may be activated after formation in the final pleated or folded configuration by applying moisture to the sheet material, prior to moulding into a product. In other embodiments, applying moisture to the sheet may not be required and, instead, the adhesive may be heat- activated or light-activated (e.g. UV-light-activated). In some embodiments, the adhesive applied to the sheets 100, 200 may advantageously provide “barrier” properties, similar to those described below for the barrier layer. For example, the adhesive or adhesive layer may itself provide a degree of fat-resistance, moisture-resistance or heat-resistance, depending on the particular adhesive that is used.

[0143] The pre-glued and activated sheet may then be formed into a moulded product 300 in the same way as described above for non-pre-glued sheets.

[0144] In some embodiments, the sheets 100, 200 may be moulded using a one-part mould, or other suitable moulds to provide a desired shape.

[0145] In some embodiments, a barrier film may be applied to the formed product 300. The barrier film may be a thin layer of material that is applied to one or more surfaces of the pleated sheet (in an unfolded, or folded configuration). The barrier film may cover substantially the whole of one surface of the pleated sheet (or one surface of the pleated sheet in its folded configuration), such that when a product is formed (e.g. moulded) using the pleated sheet, the barrier film covers substantially the whole of one surface of the formed product. The barrier film may instead cover substantially the whole of both surfaces of the pleated sheet (or both surfaces of the pleated sheet in its folded configuration), such that when a product is formed (e.g. moulded) using the pleated sheet, the barrier film covers substantially the whole of both surfaces of the formed product.

[0146] In some embodiments, a barrier film may be applied to the formed product 300 (i.e., after formation of the product 300 from a pleated sheet). The barrier film may cover the entire surface of the formed product 300, such that it forms a protective coating that seals the slits. Alternatively, the barrier film may instead be applied to part of the surface of the formed product 300 (e.g. the inner surface of a bowl or tray). The barrier film may be formed from a material having advantageous properties, depending on the particular product that is formed. For example, the material may be moisture-resistant, fat-resistant (e.g. oil-resistant) or heat resistant, or may impart moisture-, fat- or heat-resistant properties to the formed product, which may be particularly suitable for formed products intended for use with food products.

[0147] The barrier film can be adhesively applied to the formed product (including, for example, where the barrier film itself comprises an adhesive component). The barrier film may instead be formed by coating the formed product with the barrier film material (e.g. via spraying or brushing). Examples of barrier films contemplated in this invention are resins or plastics (e.g. polyethylene, polyvinyl chloride), metals (e.g. aluminium), and other suitable materials known in the art.

[0148] It is also envisaged that a barrier film can be applied during the process of forming a product 300 from a pleated sheet. That is, the barrier film may be applied immediately prior to, or simultaneously with, the formation of the product. This may be achieved by positioning the barrier material on or within a mould, such that the formation process provides both application of the barrier film to the pleated sheet and formation of the product from the pleated sheet (e.g. via heat-activation of an adhesive of the pleated sheet).

[0149] The barrier film may comprise a single layer of barrier material, or multiple layers of barrier material. It may also comprise multiple layers of different materials, depending on the particular requirements of the formed product. In some embodiments, there may be up to eight layers of barrier material(s). In other embodiments, there may be more than eight layers of barrier material(s).

[0150] The material(s) used to form the barrier film on the formed product 300 may also be used to seal contents (e.g. food items) in position relative to the product 300. For example, an additional closing layer of barrier film may be applied over a tray or bowl after inserting contents into the tray / bowl.

[0151] In general, the preliminary steps described above for forming a product from paper include: providing a roll of paper material (e.g. a continuous roll); drawing out a sheet of paper material from the roll and applying the requisite slits and fold lines to the sheet; and forming a pleated sheet from the sheet of paper material by folding the sheet about the applied fold lines in a selected manner (e.g., a ‘flat pleat’ configuration using sheet 100, or a ‘box pleat’ configuration using sheet 200).

[0152] The above steps provide a length of paper material formed into a pleated sheet. The pleated sheet may be cut at a selected length to form multiple separate pleated sheets. A further fold line can optionally be applied to a cut length of pleated sheet (for example, at a central position along the length of pleated sheet). The pleated sheet can be folded along this fold line to form the pleated sheet into a folded configuration.

[0153] Preferably, a formed (e.g. moulded) paper product can be formed using the pleated sheet in the folded configuration, or alternatively, by using a stacked configuration comprising multiple pleated sheets. These configurations will necessarily have a greater number of layers than a single (unfolded) pleated sheet. However, it is envisaged that a formed paper product (e.g. a moulded product) could be formed from a single (unfolded) pleated sheet. This may be advantageous in certain applications, providing that the single (unfolded) pleated sheet has sufficient strength to avoid tearing when a load is applied during formation of the product (for example, if the pleated sheet has sufficient thickness).

[0154] When a pleated sheet is laid out, or when tension is applied to a pleated sheet (whether in the folded or unfolded configuration), it is possible for the pleats to open, or unfold to some extent, and this may result in some regions of the pleated sheet having a reduced number of paper layers. This may inadvertently weaken the pleated sheet, for example, if the regions are ‘opened’ such that they have a thickness of less than three paper layers. This can occur if tension is applied to the pleated sheet prior to, or in the process of, forming a product (e g., when it is laid or stretched out prior to being applied to a mould). The weight of the pleated sheet itself can also result in sagging prior to being applied (e.g. lowered onto) a mould, which may act to open or unfold the pleats. Additionally, if tension is applied to the pleated sheet (e g., when forced onto a mould), the pleats may open or unfold.

[0155] The tendency for pleat separation may be alleviated by reinforcing regions of the pleated sheet.

[0156] In one example, the pleated sheet may be reinforced by applying an adhesive to selected regions of the pleated sheet. This reinforcement may be achieved by applying an adhesive, such as a heat-activated, moisture-activated, or UV-light-activated glue or bonding agent to a region of the pleated sheet. Said glue or bonding agent may be applied to the edges of the pleated sheet, for example, to the lateral edges of the pleated sheet (i.e., the edges running parallel to the longitudinal axis of the pleated sheet), as it is drawn from the roll of paper material. If working with a cut length of pleated sheet, the adhesive may be applied to the lateral edges, or to the entire perimeter of the length of pleated sheet. For embodiments in which the sheet 100, 200 is ‘pre-glued’, the adhesive may be activated in a selected region of the pleated sheet as described above (e.g. heat-activated). For example, the heat may be applied to the lateral edges of the pleated sheet to reinforce the lateral edges, while the remaining adhesive remains non-activated.

[0157] Another option is to selectively reinforce the pleated sheet by bonding selected strips of the pleated sheet - for example, strips of a selected size running perpendicular to the longitudinal axis of the pleated sheet. Alternatively, or additionally, it is possible to reinforce strips running parallel to the longitudinal axis of the pleated sheet, or at a selected angle from the longitudinal axis of the pleated sheet. It is envisaged that other (e.g. non-linear) regions of the pleated sheet may be reinforced, depending on the particular requirements for a formed product (e.g. the shape of the mould about which the product is formed). A formed (e.g. moulded) product may be produced using sections of the pleated sheet bound by reinforced regions and, as such, the shape of the reinforced regions may be selected to provide nonreinforced sections of a suitable size and shape for use with a selected mould.

[0158] Figure 15a provides a simplified illustration of a pleated sheet 400, with reinforced lateral edges 402a, 402b (for example, glued or bonded lateral edges) as described above.

[0159] Figure 15b provides another illustration of a pleated sheet 400, which, in addition to the reinforced lateral edges 402a, 402b, comprises reinforced strips 404a, 404b, 404c extending perpendicular to the longitudinal axis of the pleated sheet.

[0160] Figure 15c provides a further illustration of several possible shapes of reinforced regions (e.g. a rectangular region 406a, a parallelogram region 406b, an elliptical region 406c), where the reinforced regions 406a, 406b, 406c define correspondingly shaped non-reinforced sections of pleated sheet 400. The reinforced regions may be formed in a repeating manner (e.g. a reinforced rectangular grid 406d, defining non-reinforced rectangular areas of pleated sheet 400, as illustrated in Figure 15d).

[0161] As an alternative (or in addition) to the reinforcement by adhesive described above, the pleated sheet may be reinforced by embossing selected regions of the pleated sheet. This reinforcement may be achieved by embossing the lateral edges of the pleated sheet and / or by embossing strips running perpendicular to, or at a selected angle from, the longitudinal axis of the pleated sheet. For a cut length of pleated sheet, the emboss could be applied at the lateral edges, or around the entire perimeter.

[0162] As an example, the pleated sheet may be embossed using an embossing roll. The embossing roll is configured to contact the pleated sheet and to rotate or roll along the pleated sheet via relative movement between the two The particular embossing pattern can be selected based on particular requirements for the emboss. For example, a gear- or sprocket-like embossing tool can be utilised, wherein teeth of the gear / sprocket press and deform the paper material to provide the embossed region. It will be appreciated that embossing the paper material could be achieved using a wide range of embossing tools known in the art.

[0163] Figure 15e provides a simplified illustration of a pleated sheet 400, with reinforced (embossed) lateral edges 408a, 408b.

[0164] Another option is to reinforce the pleated sheet by punching or stamping through the pleated sheet at selected locations. Punching through the pleated sheet provides a loose flap of material, comprising a plurality of paper layers. The flap is foldable relative to the plane of the pleated sheet (for example, so that it rests flat against the surface of the pleated sheet) such that the layers grip onto one another. This achieves a similar reinforcing effect to adhering the layers together in selected regions.

[0165] Figure 15f provides a simplified illustration of a pleated sheet 400, comprising a plurality of punched sections 410 extending along the lateral edges of the pleated sheet. In the illustrated example, the punched sections are triangular, or V-shaped, and provide a V-shaped flap of material connected to the pleated sheet 400 at the base of the triangle. Figure 15g provides a close-up view of the V-shaped cut, with the dashed lines indicating the cut lines and the solid line indicating the intact portion of the cut (about which the flap is folded). It is envisaged that the punched or stamped sections may have other shapes (for example, a H-shaped cut as shown in Figure 15h, providing two rectangular flaps that may be folded relative to the pleated sheet to engage the paper layers).

[0166] The reinforcement methods described above can be applied to the pleated sheet in its original (unfolded) configuration, or the pleated sheet in its folded configuration, as required. It will be understood that a pleated sheet can be formed in several ways, using the method steps and processes described above.

[0167] One exemplary process for forming a roll of pleated sheet (i.e. a “production roll”) is set out herein and comprises the following steps:

[0168] (a) paper material is treated with an adhesive (i.e. it is a pre-glued sheet) and provided in the form of a continuous roll;

[0169] (b) paper material is drawn from the roll and passes through a cutter or slitter that forms slits in a desired slit pattern;

[0170] (c) the slitted paper material then passes through a blade pleating machine that forms fold lines and pleats in a flat pleat or box pleat configuration; and

[0171] (d) the slitted / pleated sheet is rolled around a cylinder (e.g. a solid roll of stiff cardboard material, or a metal cylinder) and forms a continuous roll.

[0172] This “roll-to-roll” process forms pleated sheets in a production roll, which is then ready to be formed into a product as described above. An exemplary production roll comprises a continuous pleated sheet having 45-degree rigid pleats on the top of the roll (e.g. the outer surface relative to the roll), and loose pleats beneath, or vice versa.

[0173] Additional steps may be included in the “roll-to-roll” process outlined above. For example, the lateral edges of the pleated sheet and / or additional regions of the pleated sheet may be reinforced as described above, prior to being rolled around the cylinder. Additionally, or alternatively, a barrier film may be applied to the pleated sheet as described above, prior to rolling the pleated sheet around the cylinder.

[0174] For similar processes involving a non-pre-glued sheet, the step of applying adhesive to the sheet material may occur after drawing the sheet from the continuous roll; after the sheet passes through the slitter; or after the sheet passes through the blade pleating machine. Alternatively, the production roll of pleated sheet may have no adhesive applied, where the adhesive may be applied as part of a later process of removing the pleated sheet from the production roll for forming a product.

[0175] The “roll-to-roll” process described above can be used to form several roll “products”. The “production roll” described above is a roll of slitted / pleated paper material. It will be appreciated that, alternatively a stand-alone slitted production roll may be produced, in which slits and fold lines are formed and the slitted production roll may be separately processed to form pleats by folding the paper material about the fold lines. In other words, in this case, the pleats are formed at a later stage,

[0176] It is also envisaged that a stacked production roll may be produced in a similar manner as described above, albeit with two or more pleated sheets in a stacked configuration rolled around a cylinder.

[0177] Many modifications may be made to the embodiments described in relation to the Figures without departing from the spirit and scope of the invention.

[0178] In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e., to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

[0179] It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country.

[0180] One or more future patent applications may be filed on the basis of, or claiming priority from, the present application. It is to be understood that the following claims are provided by way of example only and are not intended to limit the scope of what may be claimed in any such future application based on the present disclosure. Features may be added to or omitted from the claims at a later date so as to further define or redefine the invention or inventions.

Claims

Claims1. A sheet of paper material for use in making a formed product, the sheet of paper material comprising:A plurality of slits therethrough; and at least two sets of fold lines, about which the sheet is foldable into a pleated configuration.

2. A sheet of paper material according to claim 1, comprising:A plurality, such as an array, of slits extending at a first angle with respect to a longitudinal axis of the sheet of paper material, the slits including multiple sets of slits, wherein each set of slits is separated longitudinally from each other set of slits; a set of primary fold lines, wherein each primary fold line is separated from another primary fold line by a first distance; a set of secondary fold lines, wherein each secondary fold line is separated from an adjacent primary fold line by a second distance; and wherein the sheet of paper material is foldable in a first direction from a flat plane at each primary fold line and foldable in a second direction from the flat plane, opposite the first direction, at each secondary fold line, such that the sheet of paper material is formable into a pleated configuration.

3. A sheet of paper material according to claim 2, wherein the sheet of paper material, when formed into the pleated configuration, comprises a plurality of regions with at least three paper layers.

4. A sheet of paper material according to any one of the preceding claims, wherein the secondary fold lines run parallel to the primary fold lines.

5. A sheet of paper material according to any one of the preceding claims, wherein the slits in each set of slits are parallel to each other.

6. A sheet of paper material according to any one of the preceding claims, wherein the array of slits comprises a first set of slits and a second set of slits.

7. A sheet of paper material according to claim 6, wherein the first set of slits is laterally offset with respect to the second set of slits.

8. A sheet of paper material according to claim 6 or claim 7, wherein each primary fold line is positioned between a first set of slits and a second set of slits.

9. A sheet of paper material according to claim 6 or claim 7, wherein each primary fold line runs through a first set of slits or a second set of slits.

10. A sheet of paper material according to any one of claims 2 to 9, wherein each primary fold line of the set of primary fold lines and / or each secondary fold line of the set of secondary fold lines is provided with a set of slits oriented in the direction of the fold line, the set of slits extending along the length of the fold line.

11. A sheet of paper material according to any one of the preceding claims, wherein the sheet of paper material, when formed in the pleated configuration, comprises at least three layers across its whole length.

12. A sheet of paper material according to any one of claims 2 to 11, wherein the first distance is between 30mm and 50mm.

13. A sheet of paper material according to claim 12, wherein the second distance is between 10mm and 20mm.

14. A sheet of paper material according to any one of claims 2 to 13, wherein the first distance is 30mm and the second distance is 10mm.

15. A sheet of paper material according to any one of claims 2 to 13, wherein the first distance is 50mm and the second distance is 20mm.

16. A sheet of paper material according to any one of claims 2 to 15, wherein the primary fold lines and the secondary fold lines are positioned at an angle of approximately 45° from a longitudinal axis of the sheet.

17. A sheet of paper material according to claim 1, comprising:an array of slits extending at a first angle with respect to the longitudinal axis of the sheet, the array of slits including multiple sets of slits, wherein each set of slits is separated longitudinally from each other set of slits; a set of primary fold lines, a set of secondary fold lines, a set of tertiary fold lines, and a set of quaternary fold lines; wherein the sheet of paper material is foldable about each of the primary, secondary, tertiary and quaternary fold lines, such that the sheet is formable into a box pleat configuration.

18. A sheet of paper material according to claim 17, wherein the sheet of paper material, when formed into the box pleat configuration, comprises a plurality of regions with at least three paper layers.

19. A sheet of paper material according to claim 17, wherein: each primary fold line is separated from a nearest secondary fold line, and each tertiary fold line is separated from a nearest quaternary fold line, by a first distance; each secondary fold line is separated from a nearest tertiary fold line, and each quaternary fold line is separated from a neatest primary fold line, by a second distance; a set of first regions is defined between the quaternary fold lines and the primary fold lines, a set of second regions is defined between the primary fold lines and the secondary fold lines, a set of third regions is defined between the secondary fold lines and the tertiary fold lines, and a set of fourth regions is defined between the tertiary fold lines and the quaternary fold lines; and the first regions are foldable in a first direction about the primary fold lines, the second regions are foldable in a second direction about the secondary fold lines, the third regions are foldable in the second direction about the tertiary fold lines, and the fourth regions are foldable in the first direction about the quaternary fold lines, such that the sheet is formable into the box pleat configuration, where the first direction is opposite the second direction.

20. A sheet of paper material according to claim 1 , wherein the second distance is approximately double the first distance.

21. A pleated sheet comprising the sheet of paper material according to any one of the preceding claims folded along each fold line of the sets of fold lines to form the pleated configuration.

22. A pleated sheet comprising the sheet of paper material according to claim 2 folded in a first direction from a flat plane at each primary fold line and folded in a second direction from a flat plane at each secondary fold line to form the pleated configuration.

23. A pleated sheet comprising a sheet of paper material according to claim 19, wherein: the first regions of the sheet are folded in the first direction about the primary fold lines; the second regions of the sheet are folded in the second direction about the secondary fold lines; the third regions of the sheet are folded in the second direction about the tertiary fold lines; the fourth regions of the sheet are folded in the first direction about the quaternary fold lines; to form the box pleat configuration.

24. A pleated sheet according to any one of claims 21 to 23, wherein the pleated sheet comprises a plurality of regions with at least three paper layers.

25. A pleated sheet according to claim 24, wherein the pleated sheet comprises at least three paper layers across its whole length.

26. A pleated sheet according to any one of claims 21 to 26, wherein a barrier layer is applied to at least a portion of at least one surface of the pleated sheet.

27. A pleated sheet according to any one of claims 21 to 26, wherein selected regions of the pleated sheet are reinforced to prevent unfolding or opening of the pleats, wherein said reinforced regions comprise one or more of: adhered together layers of the pleated sheet at the selected regions; embossed layers of the pleated sheet at the selected regions, such that the layers are frictionally engaged with one another;punched and folded layers of the pleated sheet at selected regions, such that the layers are frictionally engaged with one another.

28. A pleated sheet according to any one of claims 21 to 27 comprising a central fold line located approximately equidistant from each end of the sheet, with the pleated sheet being foldable about the central fold line such that the pleated sheet is formable into a folded configuration in which the pleated sheet comprises a plurality of regions having at least six paper layers.

29. A pleated sheet according to claim 28, wherein the pleated sheet, when in the folded configuration, comprises a first surface and a second surface, each surface comprising primary and secondary fold lines that are opposed at an angle of approximately 90° from the primary and secondary fold lines of the other surface.

30. A stacked pleated sheet comprising at least two pleated sheets according to any one of claims 21 to 27, wherein at least a first pleated sheet is arranged on top of a second pleated sheet, such that the stacked pleated sheet comprises a plurality of regions with at least six layers.

31. A formed, such as a moulded product, comprising the sheet of paper material in the pleated configuration defined in any one of claims 1 to 20.

32. A formed, such as a moulded product, comprising the pleated sheet defined in any one of claims 21 to 29.

33. A method of forming a pleated sheet according to claim 22 comprising:(a) passing the sheet of paper material having a selected length through a slitter and forming the sets of slits;(b) forming the primary fold lines and the secondary fold lines sequentially;(c) folding the sheet of paper material in a first direction about each primary fold line; and(d) folding the sheet of paper material in a second direction about each secondary fold line to form the pleated sheet having a plurality of regions with at least three paper layers.

34. A method of forming a pleated sheet according to claim 23 comprising:(a) passing the sheet of paper material having a selected length through a slitter and forming the sets of slits,(b) forming the primary fold lines, secondary fold lines, tertiary fold lines and quaternary fold lines sequentially;(c) folding the sheet of paper material in the first direction about the primary fold lines;(d) folding the sheet of paper material in the second direction about the secondary fold lines;(e) folding the sheet of paper material in the second direction about the tertiary fold lines; and(f) folding the sheet of paper material in the first direction about the quaternary fold lines, to form the pleated sheet having a plurality of regions with at least three paper layers.

35. A method of forming a pleated sheet that can be formed into a folded configuration defined in claim 28 or claim 29 comprising:(a) cutting the pleated sheet to have a selected length;(b) forming a central fold line in the pleated sheet, the central fold line located approximately equidistant from each end of the pleated sheet; and(c) forming a further fold along the central fold line so that the pleated sheet in the folded configuration has a plurality of regions with at least six layers.

36. A method of forming a stacked sheet configuration according to claim 30 comprising:(a) cutting multiple pleated sheets, each having a selected length; and(b) stacking a first pleated sheet on top of a second pleated sheet to provide the stacked pleated sheet having a plurality of regions with at least six layers.

37. A method for forming a moulded or otherwise formed product using a pleated sheet as defined in claim 28 or claim 29, the method comprising:(a) forming the pleated sheet into the folded configuration;(b) applying an adhesive to at least one surface of the pleated sheet in the folded configuration;(c) pressing the pleated sheet in the folded configuration into a mould and heating the paper material to a selected temperature for a selected period of time; and(d) removing a moulded product from the mould.

38. A method for forming a moulded product according to claim 37 comprising applying the adhesive between a plurality of folds of the pleated sheet in the folded configuration.

39. A method for forming a moulded product using folded and pre-glued pleated sheets of a paper material, the method comprising:(a) forming pleated sheets in a folded or stacked configuration according to the method of claim 35 or claim 36, wherein the folded or stacked pleated sheets comprise an adhesive substance on at least one surface;(b) activating the adhesive;(c) pressing the pleated sheets into a mould and heating the pleated sheets to a selected temperature for a selected period of time to form a moulded product; and(d) removing the moulded product from the mould.

40. A method for forming a moulded product using pre-glued pleated sheets according to claim 39, wherein step (b) comprises applying: a. moisture to the pleated sheets when the adhesive is a moisture-activated adhesive; or b. heat to the adhesive when the adhesive is a heat-activated adhesive; or c. light to the adhesive when the adhesive is a light-activated adhesive.

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