AU2021221600A1 - Packaging printing system - Google Patents

Abstract

PACKAGING PRINTING SYSTEM ABSTRACT Forming a first recyclable base layer comprised of high density polyethylene (HDPE) and calcium carbonate, forming a second layer of recyclable plastic comprised of a Biaxially Oriented Polypropylene (BOPP) layer wherein the recyclable second layer is an externally printed BOPP layer, layering the first layer to the second layer with the intermediate liquid laminating material of a Low Density Polyethylene (LDPE) or similar resin. In process feeding the externally printed BOPP roll of material laminated to a sheet of first base layer using the intermediate liquid laminating material of the LDPE resin as the bonding agent between the two materials and flowing the liquid laminating material between the layers of the LDPE resin as the bonding agent between the two materials and applying heat to effect setting of the liquid laminating material.

Description

PACKAGING PRINTING SYSTEM

Field of the Invention

[001]The present invention relates to packaging and in particular to a method of printing on packaging.

[002]The invention has been developed primarily for use in/with commercial food packaging for transport and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.

Background of the Invention

[003]The printing industry has over the past decades comprised primarily of ink printing directly onto a final product.

[004] Packaging can be formed of cardboard packaging and can have a corrugated or fluted layer sandwiched between two outer flat planar layers connected at the tops of the corrugations therebetween. This provides a useful strong container. Although partially useful as a nonporous insulation layer, when ice or moisture is present, cardboard packaging loses all structural integrity.

[005]In order to make the container lightweight but nonporous, efficient, and closable, there has been the use of waxed cardboard or polystyrene containers.

[006]Waxed cardboard is corrugated (multi-layered) cardboard that is wax impregnated using a cascading wax system and polyolefin wax. Waxed cardboard is not recyclable and is highly flammable. Waxed cardboard is primarily used in wet environments and to achieve performance in these wet humid conditions and assist the cardboard in maintaining structural integrity.

[007] PE Lined cardboard is corrugated (multi-layered) cardboard that is lined with polyethylene to prevent it from getting soggy. The material can be mistaken for cardboard or paperboard. These boxes are mostly used by retailers and rarely by consumers. Most consumer products are packaged in paperboard instead of corrugated cardboard and has a polyethylene lining. Retailers primarily use this type of box to ship produce seafood, meat and poultry.

[008]Polystyrene, which is also known as "Styrofoam" or EPS is a petroleum-based plastic used in all kinds of products, from cups and trays to insulation and packaging. Most of the items made from polystyrene are designed to be single use. Another problem is that it contains toxic substances including Styrene and Benzene. These are suspected carcinogens and neurotoxins that are hazardous to humans. Hot foods and liquids start a partial breakdown causing some toxins to be absorbed into the bloodstream and tissue.

[009]Another key problem with polystyrene is that it is incredibly hard to dispose of. It is bulky and non-biodegradable, which means it takes up a vast amount of space in our landfill. It is very light and breaks down into little pieces, which means it is easily distributed across the environment.

[0010] Expanded Poly Styrene (EPS) has excellent cushioning and nonporous insulation properties and is therefore widely used to transport fresh produce, electronics and other goods. Waste management and recycling are problematic. EPS is bulky and therefore difficult and expensive to dispose.

[0011] While EPS is recyclable, it is generally uneconomic to collect and recycle because of the high volume-to-weight ratio, high costs of storage and transport and the low value of the recycled material. Approximately 22,000 tonnes of EPS packaging were placed onto the Australian market in 2017-18 (including 12,000 tonnes of business-to-business (B2B) packaging) and circa 4,000 tonnes were recycled. This equates to a recycling rate of around 18%. Most recovery is from large end users such as fish and produce markets. The remainder - around 18,000 tonnes or 360,000 m3 - was sent to landfill. Around 240,000m3 of this was B2B packaging including boxes.

[0012] One of the original mandates for applicant is to replace waxed cardboard and polystyrene as these products are not being recycled and are difficult or not readily able to be recycled.

[0013] As well as the above problems, it can be seen that known prior art printing on packaging has the problems of:

a) Use of non- environmentally friendly material

b) Final packaging can have a rough or corrugated surface which affects print quality,

c) Printing often fails on packaging used in moist, refrigerated or iced locations to keep food preserved

d) Lightweight packaging can be readily damaged in a printing press application

e) Blow on printing for large packaging results in imprecise imaging.

[0014] The present invention seeks to provide an improved packaging printing system, which will overcome or substantially ameliorate at least one or more of the deficiencies of the prior art, or to at least provide an alternative.

Summary of the Invention

[0015] According to the present invention, there is provided a method of forming a packaging printing for use as a recyclable nonporous container, the method comprising the steps of:

a) Forming a first recyclable base layer

b) Forming a second layer of recyclable plastic

c) Layering the first layer to the second layer with the intermediate liquid laminating material

d) Joining first and second layers by flowing a liquid laminating material between the layers by applying heat to effect setting of the liquid laminating material and effect a lamination of the first layer and the second layer

e) Wherein part of first or second layer is a printed layer.

[0016] It can be seen that the invention provides the benefit of using recyclable material.

[0017] According to a particularly preferred second aspect of the present invention, the recyclable first layer is high density polyethylene (HDPE) and calcium carbonate.

[0018] It can be seen that the invention provides the use of a plastic in lower quantities and together with the natural product of calcium carbonate that has zero carbon energy rating and therefore a significant benefit of being environmentally friendly.

[0019] However the method of use of these effective materials needed to overcome significant problems including how to combine them as resins and normal joining methods were unsuccessful.

[0020] In one form the invention provides a method of forming a packaging printing for use as a recyclable nonporous container, the method comprising the steps of:

a) Forming a first recyclable base layer comprised of high density polyethylene (HDPE) and calcium carbonate

b) Forming a second layer of recyclable plastic comprised of a Biaxially Oriented Polypropylene (BOPP) layer wherein the recyclable second layer is an externally printed BOPP layer c) Layering the first layer to the second layer with the intermediate liquid laminating material of a Low Density Polyethylene (LDPE) or similar resin.

d) Feeding the externally printed BOPP roll of material laminated to a sheet of first base layer using the intermediate liquid laminating material of the LDPE resin as the bonding agent between the two materials

e) flowing the liquid laminating material between the layers of the LDPE resin as the bonding agent between the two materials

f) applying heat to effect setting of the liquid laminating material

wherein there is effected a lamination of the first layer and the printed second layer and

wherein the packaging can be substantially assembled with improving security including any one or more of the following:

i. improvements in printing quality

ii. ability for system to be used in moist environments such as in refrigeration or with ice packing

iii. assembly means that does not affect quality of print and smoothness of the look

iv. able to knocked down easily

v. able to be washed and sanitized

vi. able to be reused multiple times following washing and sanitizing.

[0021] Other aspects of the invention are also disclosed.

Brief Description of the Drawings

[0022] Notwithstanding any other forms which may fall within the scope of the present invention, preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic box view of a method of forming a packaging lamination according to one aspect of the invention.

Figure 2 shows a diagrammatic box view of the material process steps of method of forming a packaging lamination of the sheeting of figure 1.

Figure 3 shows a diagrammatic view of the input of various materials for mixing and extrusion into a first recyclable base layer according to one aspect of the invention.

Figure 4 shows a diagrammatic view of the calendarizing of the first recyclable base layer of figure 3.

Figure 5 shows a diagrammatic view of the combining of a multi-layer printed layer packaging sheeting with LDPE resin as the intermediate liquid laminating material according to one aspect of the invention.

Figures 6 show diagrammatic view of corrugation of top and bottom layers of interposed sheets for packaging sheeting with printed sheeting joined according to further aspects of the invention.

Fig. 7 is a diagrammatic view of use of hexagonal shaped cells with channels therebetween forming a matrix fluting as one example of possible polygonal shaped cells.

Fig. 8 is a diagrammatic cross sectional view of laterally consistent profile fluting of variable suitable dimensions

Fig. 9 is a diagrammatic view of control system of the stretch variation of the sheeting by control of the speed ratio between the main corrugator and the auxiliary machine of corrugate. The main machine is corrugator machine, and auxiliary machine is the forming machine and the cooling machine.

Description of Preferred Embodiments

[0023] It should be noted in the following description that like or the same reference numerals in different embodiments denote the same or similar features.

[0024] Referring to Fig 1 there is shown a method of forming a packaging printing for use as a recyclable nonporous container, the method comprising the steps of:

a) Forming a first recyclable base layer

b) Forming a second layer of recyclable plastic

c) Layering the first layer to the second layer with the intermediate liquid laminating material

d) Joining first and second layers by flowing a liquid laminating material between the layers by applying heat to effect setting of the liquid laminating material and effect a lamination of the first layer and the second layer.

[0025] Customers' demands are that products are often required to be printed and this process was extremely difficult to achieve the result previously. The process included no less than 7 different ideas and trials around the combinations of printing process and materials in order to achieve the print result we have today. Each trial was an innovative look at printing a substrate and laminating that substrate to our first base layer material. The challenge was what inks to use / what printing material to use / what adhesive to use / when to apply the adhesive and or any combination of these processes e.g., at the printing stage or at the laminating stage. All these processes were trialed until we came up with the current process which is listed below.

[0026] First Recyclable Layer.

[0027] Referring to Figs 3 and 4, the first layer 30, known as UNIQCOR film, is formed from 45-80% calcium carbonate (limestone) and 20-55% high density polyethylene (HDPE). The limestone is extracted from existing limestone quarries and processed into a fine powder. The HDPE is currently manufactured from non-renewable oil and gas, but renewable alternatives including plastics made from sugar cane or other biodegradable plant-based resins are being investigated as well as 100% recycled HDPE.

[0028] The plastics material can be a composite material. The composite material can be polyethylene combined with calcium carbonate. Recycled polyethylene can also be included. The percentages of polyethylene, calcium carbonate, and recycled polyethylene can depend on the application of the sheeting.

[0029] As shown in Fig 3 the various materials are introduced into vessels 21, 22, 23 24 and mixed under heat in vessel 25. The material is extruded in Die vessel 28 and out extrusion nozzle 29. As per Fig. 4 the extruded film is passed through calander rollers 31 calanderised to required thickness and density and made into continuous rolls 32.

[0030] A thickness of the material used for the material can be from about 100 gsm to about 750 gsm, depending on the application. A thickness of the material used for the interposed sheet 16 can be from about 100 gsm to about 750 gsm, depending on the application. Other thickness materials can be used in packaging sheeting according to the invention.

[0031] Second Layer

[0032] The print is undertaken on a very thin low micron BOPP film (Biaxially-Oriented Polypropylene) Biaxially is film stretched in both machine and transverse directions, producing molecular chain orientation in two directions. This inherently gives the film good X and Y Axis strength.

[0033] Fluting

[0034] As per Figs 6, 7 and 8, the printing system does not require the use of fluting structures. However it can still be used when fluting is used. As shown in Figs 7 and 8, this can be by honeycomb or polygon profile 55 with spacing channels 57 inbetween or circular flute profile or by standard laterally extending profiles 59 with consistent cross-sectional profile.

[0035] The corrugating process incorporates heat lamination as well as resin lamination which increases the speed of production and increases the strength of the lamination and maintains the recyclability. Immediately after the flute has been formed using the heated flute roller and before the flute comes in contact with the top and bottom sheet, a resin is applied to the bottom sheet and the top of the flute and as the sheets then come together to form combined sheet with the resin bonds the tips of the flute to the top and bottom sheets forming a more rigid board and running at speed of up to 5 times or more the current process. This solution and technology are possible due to the BOPP lamination.

[0036] With the honeycomb or polygon or circular flute profile we need to maintain the element of adding liquid or foam resins to the open cells before the top laminated sheet goes on and that these elements added provide additional unique properties to these boxes for various applications such as thermal. These elements are added as resins between the fluting being produced and the top sheet being laminated.

[0037] With the standard laterally extending profiles with consistent cross-sectional profile, the profile can be a new and more effective profile such as shown in Fig 8 where there is differing heights of 3, 4, or 5 millimetres with differing wavelength in the range of 5.64 to 6.31 mm which gives a varying linear wall angle of 20 to 30° on the substantially sinusoidal cross section but which can be more a linear sinusoidal shape.

[0038] Lamination

[0039] Referring to the drawings there is shown in Fig 5 that if printing is required on one of these first layer sheets 32, it is fed into the laminating machine and an externally printed BOPP roll of material 33 forming the second layer is laminated to the sheet of the first sheet using LDPE resin 41 as the bonding agent between the two materials. This is required as these two materials do not cleanly / naturally bond using heat or many other resins.

[0040] We then produce the top sheet of the novel recyclable first layer which is a plastic material with natural additives. The recyclable first layer is most preferably high-density polyethylene (HDPE) and calcium carbonate material.

[0041] Before any layers are corrugated together with the bottom sheet and the flute there is a laminating process in house where the film is run and laminated to the first layer top sheet.

[0042] The lamination process is the joining of the printed BOPP with the HDPE first layer top sheet. This process is done using LDPE resin as a bonding agent under heat between BOPP and HDPE. In essence the 2 materials of BOPP and HDPE will not bond directly together. However, when a thin waterfall of LDPE resin is melted 41 and cascaded from resin cascade extruder 42 between the 2 sheets 32, 33 as they come together this forms a bond that is virtually inseparable.

[0043] From here the printed top sheet of BOPP 33 is now combined with the first layer top sheet of HDPE 32 and is left to cure and harden the LDPE resin combining the two surfaces. As shown in Fig 6 the material is then put on the corrugator 45 to be combined with the flute 35 and bottom sheet 36.

[0044] Of note is that we have other print options like using straight polyethylene or Cast Polypropylene (CPP), with PE film we can directly laminate film to top sheets without the need for LDPE bonding agent due to the synergies between HDPE and PE (Like materials) However, the print quality is nowhere near as high quality as the BOPP.

[0045] What seems so unique in this process is that the laminating process of the printed film to the first layer top sheet needs to be done in a way that does not distort or stretch the print. In addition to this when the material is then corrugated and combined with the Flute and the bottom sheet again there needs to be negligible or no distortion or stretch of the print. In addition, this process needs to ensure there is no ink transfer through the heating used to corrugate the top sheet to the flute and the bottom sheet.

[0046] These were all situations that occurred during the previous 6 trials undertaken before refining to this latest process. As well as these elements in inventing this combination and using BOPP laminated to our HDPE we maintained the recyclability of the material as well as created a cross directional strength by laminating the two materials.

[0047] The Laminator speed is 35m to 120m per minute. This speed although quite slow for a laminating process at approximately 1/3 of normal laminating process speed, allows for the even spread of the LDPE as well as the 100% contact adhesion when this speed is combined with the 200 degree resin temperature at time of contact and 310-320 degree melted temperature within the process.

[0048] A printed sheet laminated to first base layer gives between 10-20% increased puncture resistance / burst and rigidity in the material. There is the ability to put this print on both the inside and the outside liners of the material through the same process and corrugate the material with both print surfaces applied to the flute in a single pass

[0049] The film can be laminated to both sides of our material and combined when corrugated so that the material is printed on both sides, Material thickness can range from 100 gsm up to 1000 gsm.

[0050] Resin

[0051] - The Low-density Polyethylene (LDPE) resin can be of the type polymer-E with the following characteristics:

9. Physical and Chemical Properties / Characteristics Appearance (physical static, color, etc): Odor: negligible Translucent white solid pellets Odor threshold: --- Melting Point / Melting Range: 100-111°C pH Valve: Not applicable Boiling point/boiling point range: Not applicable Flammability (solid, gas): Not applicable Flash Point: ca.340°C Decomposition Temperature: Not applicable Test Method: Close Cup Auto-ignition Temperature: 349°C Exposure limit: Not applicable Vapor Pressure: Not applicable Vapor Density: Not applicable Density: 0.915-0.926 g/cm3 Solubility In Water: Nil. Portion coefficient(n-octanol/water, log Kow):--- Evaporation rate: Not applicable

Examples

a) For the Print sheet to the outside liner

[0053] Low Density Polyethylene is used as the inner layer of composite packaging bag, that is, multilayer composite film heat sealing substrate. The melting point is 110-1150 C processing temperature 150-210.

[0054] The exact temperature range that the LDPE is run at when laminating is 310 to 320 degree temperature as during lamination it is necessary to eliminate bubbles and obtain smoothrunning. At the point at which the materials come in contact with each other and the LDPE resin the temperature is between 150-21Odegres These temperatures are relevant to the thickness of the materials being laminated and ensuring a clean lamination with no distortion.

[0055] In the process of lamination when applied at between 310 and 320 degree, this temperature of the LDPE effects melting to ensure enough flowability in the extrusion well

(enough flow and good thickness of curtain coating film). The thickness of curtain coating and therefore the temperature is a key item for the lamination process.

[0056] The Laminator speed is 35m to 120m per minute. This speed although quite slow for a laminating process at approximately 1/3 of normal laminating process speed, allows for the even spread of the LDPE as well as the 100% contact adhesion when this speed is combined with the 200 degree resin temperature at time of contact and 310-320 degree melted temperature within the process.

[0057] Referring to Fig. 9, the stretch variation is controlled by the speed ratio between the main corrugator 61 and the auxiliary machine 62 of corrugate. The main machine is a corrugator machine, and the auxiliary machine is a forming machine and the cooling machine. In general, we apply high speed for auxiliary machine 62 and low speed for auxiliary machine 61 and lowest speed for corrugate machine 63 to assure there have enough heat and tension to avoid the board crushing. The tension force controls the stretch for UNIQCOR printed board in the process of cooling and forming the board. Their ration is 1.06 to 1.2. based on the actual material, temperature and situation of the run. This means the material is stretched to 1.06 to 1.2 of normal length and then allowed to relax back when mounted in place.

[0058] To keep the roll pressure release and release with a steady stretching force. If the stretch force changes quickly this can cause the laminating stretch and shrinkage problem. We need to keep the pressure steady and at a relative status to the HDPE sheet using the special auto tensioning machine. We apply the 1.06 as stretch rate. Other words, the length of cutting board compared with the length of print pattern (based on the same position line) is 1.06. This dimension is specified for our BOPP print pattern to check it and mark it on the job notice and then to set the parameter of machine to ensure the final dimensions meet the required specification. The operator will measure the width and length of the cut board and approve based on their QA Die line. They will then adjust accordingly to meet required specification.

[0059] We avoid bubbles spots in the lamination by using the correct combination of LDPE heat and lamination speed. Initially significant bubbles and spots were caused by moisture getting into the LDPE resin, and after heat in the extruding machine we noticed bubbles in the curtain coating process which can only be seen after the laminate process is completed which is then too late. Now all LDPE will be heated to a stable temperature of 70 to 90 degree for more than thirty minutes to eliminate any moisture and eliminating the risk during production.

[0060] In order to avoid the transfer of the ink either to another surface or simply rubbing off on other surfaces we need to corona treat all materials. The corona treatment is the process of putting an electrostatic charge through the material which causes a sticky type arrangement when the ink and the BOPP comes in contact with it. The BOPP also has a corona treatment applied to it, meaning both surfaces have a stickiness to them,

[0061] The purpose of corona treatment increases the surface energy and roughness of our films, is to improve wettability and adhesion of inks, coatings and adhesives. Treating works is best when a substrate is treated at the time of extrusion and in-line prior to converting. We do this to produce enough roughness that makes the ink and other materials bond. With the BOPP film it has strong bond strength which can after corona treatment and lamination then sustain normal peel test. We use a dyne pen to measure this roughness after the corona treatment. We can perform the DOE to find the right value of Dyne (roughness) and right parameter of corona process. electronic power and time.

b) For the Print sheet to the Inside liner

[0062] This system applies the same as above

c) For the corrugating process when only the outside print sheet is applied

[0075] The temperature that the corrugator is run at is different when we have print and when we do not have print. When we run plain material, we apply 140 degree temperature on corrugator for print and 135 degree for plain material not printed. For top film in the process of corrugating we need to melt all film in order to attach well to the flute, with the addition of the print lamination we need more energy / heat to get equivalent bond / melt temperature. so. the flute and bottom film if not printed have no temperature change to ensure the print has no effect on the middle and bottom film, we adjust the temperature based on their thickness and run speed.

[0076] To avoid the stretch or shrinkage with the heat when corrugating - we apply our designed auto-release device to control stretch force for all rolls release feed to corrugate machine, and adjust speed rate of cool system and corrugate machine to keep the stretch force obtained on the machine and collected at each process steady. Generally speaking we apply 1:1.1 to each of the 3 layers with their speed rate. and will adjust it based on the final production dimension measurement for corrugate process uniformly during production. This process is unique to each and every print / material combination.

[0077] There are challenges with registration for the print sheet and with the cutting knife at the end of the line dictating the cut length of the sheet to registration needs more development and leads to a shift in material of up to +/- 3-7 mm. A high precision rotary cutting / flat bed die cutting tool for the finish cut sheet size is used in order to get the accurate print dimension outcome.

d) For the corrugating process when both the outside print sheet and the inside liner are applied - so when both sides have a print sheet

[0078] The temperature we run the corrugator at and is the difference to when we only corrugate with the print sheet or when we do not have any print and just run plain material is the same as above

[0079] The processes around avoiding the stretch or shrinkage with the heat when corrugating when we must laminate BOPP to the inside and the outside is the same as above

[0080] The challenges with registration for the print sheet when we are also laminating BOPP to the inside and is there any different technology used to manage this as compared to a single print sheet to the top liner is the same as above

Interpretation

Embodiments:

[0081] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[0082] Similarly it should be appreciated that in the above description of example embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects.

This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description of Specific Embodiments are hereby expressly incorporated into this Detailed Description of Specific Embodiments, with each claim standing on its own as a separate embodiment of this invention.

[0083] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Different Instances of Objects

[0084] As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

Specific Details

[0085] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Terminology

[0086] In describing the preferred embodiment of the invention illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "forward", "rearward", "radially", "peripherally", "upwardly", "downwardly", and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

Comprising and Including

[0087] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" are 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.

[0088] Any one of the terms: including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

Scope of Invention

[0089] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[0090] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.

Industrial Applicability

[0091] It is apparent from the above, that the arrangements described are applicable to the box and container industries for use in such areas as commercial food.

Definitions

BOPP Biaxially Oriented Polypropylene Metalised Biaxially Oriented Polypropylene LDPE Low Density Polypropylene HDPE High Density Polypropylene PE Polyethylene

Claims (17)

Claims The claims defining the invention are as follows:

1. A method of forming a packaging printing for use on a recyclable nonporous container, the method comprising the steps of:

a. Forming a first recyclable base layer

b. Forming a second layer of recyclable plastic

c. Layering the first layer to the second layer with the intermediate liquid laminating material

d. Joining first and second layers by flowing a liquid laminating material between the layers by applying heat to effect setting of the liquid laminating material and effect a lamination of the first layer and the second layer

e. Wherein part of first or second layer is a printed layer.

2. A method according to claim 1 wherein the recyclable first layer is a plastic material with natural additives.

3. A method according to claim 1 wherein the recyclable first layer is high density polyethylene (HDPE) and calcium carbonate.

4. A method according to claim 1 wherein the recyclable second layer is a Biaxially Oriented Polypropylene (BOPP) layer.

5. A method according to claim 1 wherein the recyclable second layer is an externally printed BOPP layer.

6. A method according to claim 5 wherein an externally printed BOPP roll of material is laminated to a sheet of first base layer using LDPE resin as the bonding agent between the two materials.

7. A method according to claim 1 wherein the intermediate liquid laminating material is a Low Density Polyethylene (LDPE).

8. A method according to claim 7 wherein the Low Density Polyethylene (LDPE) has a melting point of between 110 and 1150C and the processing temperature is substantially between 150 and 210°C.

9. A method according to claims wherein the first layer and the second layer are in rolls and fed into a laminating machine at a speed that matches the supply from the extruding with the speed of the laminating.

10. A method according to claim 9 wherein the speed is substantially between 35 to 120 metres per minute.

11. A method according to claim10 wherein the second layer isfed at a comparative tension of a stretch rate of 1.06 relative to the first layer.

12. A method according to claim11 wherein the comparative tension is provided by tensioning through the laminating machine and released by the cutting to packaging requirement size after lamination.

13. A method according to claim 1 wherein one of the layers is a fluting layer.

14. A method according to claim 1 wherein the first or second layers is a PE layer and the other of the first or second layers is a BOPP layer

15. A method according to claim 1 wherein one of the layers is a BOPP layer.

16. A method according to any one of the preceding claims wherein the layers form a recyclable nonporous container.

17. A method of forming a packaging printing sheet for use as a recyclable printable top sheet or nonporous container, the method comprising the steps of:

a. Forming a first recyclable base layer comprised of high density polyethylene (HDPE) and calcium carbonate

b. Forming a second layer of recyclable plastic comprised of a Biaxially Oriented Polypropylene (BOPP) layer wherein the recyclable second layer is an externally printed BOPP layer

c. Layering the first layer to the second layer with the intermediate liquid laminating material of a Low Density Polyethylene (LDPE).

d. Feeding the externally printed BOPP roll of material laminated to a sheet of first base layer using the intermediate liquid laminating material of the LDPE resin as the bonding agent between the two materials

e. flowing the liquid laminating material between the layers of the LDPE resin as the bonding agent between the two materials

f. applying heat to effect setting of the liquid laminating material

wherein there is effected a lamination of the first layer and the printed second layer.