GB2612651A

GB2612651A - Thermally insulating packaging

Info

Publication number: GB2612651A
Application number: GB2116099.9A
Authority: GB
Inventors: Andrew Midgley Stephen; Adrian Cotton Mark
Original assignee: John Cotton Group Ltd
Current assignee: John Cotton Group Ltd
Priority date: 2021-11-09
Filing date: 2021-11-09
Publication date: 2023-05-10
Anticipated expiration: 2041-11-09
Also published as: GB2612651A8; GB2612651B

Abstract

Thermally insulating packaging 100, 100’, 100’’ comprises a cellulosic paper pulp mat 110 between first and second cellulosic sheet paper layers 120. The first and second layers extend into a margin M around the mat and a first adhesive bonds together the first and second sheet paper layers (120) within the margin (M). The mat may have a thickness of at least 15mm. Preferably at least 70%wt of the fibres within the mat have fibre lengths of 3 to 15mm. The mat may comprise a mix of first and second fibres, wherein the average length of the second fibres is longer than the average length of the first fibres: preferably the first fibre length is 3 to 8mm and the second fibre length is 10 to 15mm. A method of manufacturing the packaging by arranging and then bonding the layers is also claimed.

Description

THERMALLY INSULATING PACKAGING

TECHNICAL FIELD

The present invention relates to thermally insulating packaging, and more particularly, but not exclusively, to a thermally insulating packaging for use in the storage and transport of foodstuffs, horticultural products and pharmaceuticals.

BACKGROUND

Thermally insulating packaging is used in transporting chilled foodstuffs, pharmaceuticals, heated foodstuffs, and other temperature sensitive products. For example, users may need to maintain the temperature of chilled goods below 8°C for 24 hours to 48 hours, when exposed to particular ambient conditions (e.g. 24°C). In use, the chilled goods are commonly enclosed within the thermally insulating packaging with an ice pack.

Current thermally insulating packing is commonly made with a high percentage of polyester fibres, e.g. recycled polyethylene terephthalate (rPET) from recycled plastic bottles. The fibres may be bound by use of binder fibres (e.g. low melting temperature fibres, or core and sheath fibres having a sheath with a lower melting temperature than the core), and enclosed within a sheet polyethylene bag. Often, such products are not readily recyclable with current curb-side domestic recycling, and instead are commonly disposed of as household landfill waste.

SUMMARY OF THE DISCLOSURE

According to a first aspect, there is provided thermally insulating packaging comprising a cellulosic paper pulp mat between first and second cellulosic sheet paper layers, wherein the first and second sheet paper layers extend into a margin around the paper pulp mat and first adhesive bonds together the first and second sheet paper layers within the margin.

According to a second aspect, there is provided a method of manufacturing thermally insulating packaging comprising: providing a cellulosic paper pulp mat between first and second cellulosic paper layers, wherein the first and second sheet paper layers extend into a margin around the paper pulp mat; and bonding together the first and second sheet paper layers within the margin with a first adhesive.

The paper pulp mat may have a thickness of at least 15mm. The paper pulp mat may have a thickness of at least 20mm.

At least 70%wt of the fibres within the cellulosic paper pulp mat may have fibre lengths of 3 to 15 mm. At least 80%wt of the fibres within the cellulosic paper pulp mat may have fibre lengths of 3 to 15 mm. At least 90%wt of the fibres within the cellulosic paper pulp mat may have fibre lengths of 3 to 15mm.

The cellulosic fibres within the cellulosic paper pulp mat may comprise a mixture of first fibres and second fibres, wherein the average length of the second fibres is longer than the average length of the first fibres.

At least 70%wt of the cellulosic fibres within the paper pulp mat may have a fibre length within either a first fibre length range of 3mm to 8mm or within a second fibre length range of 10mm to 15mm. At least 80%wt of the cellulosic fibres within the paper pulp mat may have a fibre length within either a first length range of 3mm to 8mm or within a second length range of 10mm to 15mm. At least 90%wt of the cellulosic fibres within the paper pulp mat may have a fibre length within either a first length range of 3mm to 8mm or within a second length range of 10mm to 15mm.

The average fibre length frequency within an intermediary length range of between 8mm and 10mm is lower than the average fibre length frequency within each of the first and second fibre length ranges. The average fibre length frequency within an intermediary length range of between 8mm and 10mm may be at least 30% lower than the average fibre length frequency within each of the first and second fibre length ranges.

The cellulosic paper pulp may comprise 5% to 8%wt water.

The volumetric mass density of the cellulosic paper pulp in the paper pulp mat may be within the range 20 to 50 kg/m2.

The cellulosic sheet paper may have an areal mass density of 40 to 100 g/m2.

At least one of the cellulosic paper layers may be provided with a waterproof coating.

The thermally insulating packaging may be folded and secured in a folded configuration by bonding with a second adhesive within the margin.

The first adhesive and any second adhesive may be provided as an intermittent pattern of adhesive extending along the margin.

A patterned further adhesive may be provided on an face of a sheet paper layer facing towards the paper pulp mat.

The method may comprise air laying cellulosic fibres to form a paper pulp layer from which the paper pulp mat is cut.

The method may comprise dampening the cellulosic fibres to comprise 5 to 8Vowt of water before air laying.

The method may comprise passing cellulosic fibres through a plurality of rotating spiked rollers before deposition onto a conveyor belt to form the paper pulp layer.

The method may comprise compressing the paper pulp layer or paper pulp mat before providing the cellulosic paper pulp mat between first and second cellulosic paper layers.

The cellulosic fibres may be formed by milling paper or cardboard with a hammer mill.

The milled paper or carboard may be separated by at least one hole screen having first holes and second holes, wherein the second holes are larger than the first holes.

The first holes may have a maximum dimension of 9mm to 13mm and the second holes may have a maximum dimension of 13mm to 17mm. The first holes may have a maximum dimension of lOmm to 12mm and the second holes may have a maximum dimension of 14mm to 16mm.

The method may comprise folding the thermally insulating packaging and bonding with a second adhesive to retain the thermally insulating packaging in a folded configuration.

The method may comprise applying a patterned further adhesive to a face of a sheet paper layer for gripping the paper pulp mat within the thermally insulating packaging.

DESCRIPTION OF THE DRAWINGS

Examples are further described hereinafter with reference to the accompanying drawings, in which: * Figure 1A shows a cross-sectional view through first thermally insulating packaging; * Figure 1B shows a plan view of the first thermally insulating packaging of Figure 1A; * Figure 10 shows a plan view of second thermally insulating packaging; * Figure 1D shows a cross-sectional view through the second thermally insulating packaging of Figures 10; * Figure 1E shows a plan view of a third thermally insulating packaging; * Figure 1F shows the second thermally insulating packaging of Figure 10 filled with exemplary chilled foodstuffs and an ice pack; * Figure 2A shows part of a hole screen; * Figure 2B shows an air laying process, and forming a three-layer structure; * Figure 20 shows a paper pulp layer compression process; * Figure 3A shows a plan view of a fourth thermally insulating packaging; * Figure 3B shows a plan view of a fifth thermally insulating packaging; * Figures 4A and 4B show a cross-section and a plan view of a sixth thermally insulating packaging; and * Figures 40 and 4D show side and end views of applying a pattern of adhesive to a sheet paper layer.

DETAILED DESCRIPTION

Like reference numerals refer to like elements throughout. In the described examples, like features have been identified with like numerals, albeit in some cases having typographical marks and increments of 100. For example, in different figures, 100, 100' and 100", 300 have been used to indicate thermally insulating packaging.

Figure 1A shows a cross-sectional view and Figure 1B shows a plan view of a thermally insulating packaging 100 (e.g. a thermally insulating wrap) formed from an assembly of cellulosic paper pulp mat 110 sandwiched between cellulosic sheet paper layers 120. Figure 1A corresponds to the cross-section indicated by line A-A in Figure 1B.

The cellulosic paper pulp mat 110 and cellulosic sheet paper layers 120 may each substantially comprise cellulosic fibres from wood pulp, e.g. they may each comprise at least 90%wt cellulosic wood pulp fibres, or substantially 100%wt cellulosic wood pulp fibres.

The sheet paper layers 120 extend beyond the periphery of paper pulp mat 110, being provided with a margin M around the paper pulp mat, from which the paper pulp is absent. Within the margin M, the sheet paper layers 120 are bonded together by a first adhesive 130, forming a seal surrounding the wood pulp layer 110, substantially containing any loose fine particulate from the paper pulp mat 110 between the sheet paper layers, and preventing the contamination of products that are being thermally insulated by the thermally insulating packaging, or the surrounding environment, in use The cellulosic paper pulp mat 110 traps air between its fibres, providing enhanced thermal insulation (e.g. compared with a corresponding mass of cellulosic paper fibres formed into sheet paper). The fibres of the cellulosic paper pulp mat 110 may be air laid, which provides enhanced trapping of air between the laid fibres, and enhances the volume (provides bulk), providing enhanced thermal insulation. The air laid fibres provide a low density paper pulp mat 110, providing enhanced thermal insulation with a low mass.

To assemble the thermally insulating wrap 100 illustrated in Figures 1A and 1B: * A pre-cut paper pulp mat 110 is sandwiched between the sheet paper layers 120, to form a blank 102.

* First adhesive 130 is used to bond together the sheet paper layers 120 within the margin M around the cellulosic paper pulp mat 110. The first adhesive 130 may extend along each edge 104A, 104B, 104C, 104D of the blank 102.

By provided a margin M around the paper pulp mat, from which the paper pulp is absent, the thermally insulating wrap 100 may be assembled with paper pulp mat 100 having a substantial thickness. This may enable assembly with greater thicknesses of paper pulp mats 100 and/or with greater reliability than would be possible by bonding between the sheet paper layers 120 with adhesive that penetrates through the paper pulp mat.

The thermally insulating packaging 100 (e.g. a thermally insulating wrap) may be used as a thermally insulating liner within a box (e.g. a carboard box), for ease of transportation and handling.

Alternatively, the thermally insulating packaging may be formed as a thermally insulating bag (pouch) 100' or 100", as illustrated in Figures 1C to 1F.

An assembly method of the thermally insulating bag 100' of Figure 1B:

S

* The thermally insulating wrap 100 of Figure 1A may be folded over, along a fold line F, indicated by F-F in Figure 1B. The fold line F may be offset from the mid-point between two opposed edges 104A, 104B, to overlap the majority of the two parts of the blank 102, whilst leaving an exposed flap 106 adjacent the opening 108', as shown in Figure 10.

The flap 106 may be used as a closure for the opening 108', e.g. being secured by adhesive, an adhesive label or adhesive tape.

* The folded wrap 100 may be secured using second adhesive 140 The second adhesive 140 may extend along the first adhesive 1300, 130D (e.g. the four sheet paper layers 120 may be formed into a bonded stack by successive layer of first adhesive 130, second adhesive 140 and first adhesive 130. The section indicated by line D-D corresponds with the cross-sectional view of Figure 10 Figure 1E shows a thermally insulating bag 100" that is similar to the thermally insulating bag 100' of Figure 10, being folded about fold line F between the opposed edges 104A, 104B, with the exposed flap 106 shown in Figure 10, adjacent the opening 108'. The section indicated by line D-D also corresponds with the cross-sectional view of Figure 1D.

The formation of a thermally insulating bag 100', 100" with a folded edge 104F', 104F" opposite to the opening 108', 108" increases the strength of the thermally insulating bag. Away from the corners 104X of the thermally insulating bag 100', 100', the sheet paper layers 120 may more easily form a curved end to the interior opposite to the opening of the bag, than may be possible for a corresponding edge that is bonded with adhesive. The thermally insulating bag 100', 100" may be stood upright on the folded edge 104F', 104F" during filling and transport. The curved end to the interior of the thermally insulating bag 100', 100" may more easily conform to the shape of inserted objects with relatively sharp edges and corners (e.g. the corners of rectangular cuboidal boxes), than an adhered edge. Accordingly, the provision of the folded edge may reduce the risk that the corners of packaging within the bag penetrate the adjacent (internal) sheet paper layer 120 and compromise the integrity of the paper pulp mat 110.

The thermally insulating packaging 100, 100', 100" (e.g. thermally insulating wrap or thermally insulating bag or pouch) may be used as a thermally insulating liner within a box (e.g. a carboard box), for ease of transportation and handling.

At least 70%wt of the cellulosic fibres within the paper pulp mat 110 have a fibre length range of 3mm to 15mm (e.g. at least 80%wt or at least 90'%wt of the fibres are within this range). A greater proportion (by mass) of fibres having a shorter fibre length would form a more densely packed paper pulp mat, when deposited, with a reduced proportion of micro-pockets of air within the paper pulp mat. A greater proportion (by mass) of fibres above this length range would be more difficult to process for air laying, and would result in less cohesion between fibres, which may result in a paper pulp mat that could deteriorate in handling, and may produce an uneven paper pulp mat, impairing thermal insulation performance (e.g. with areas of reduced air entrapment between the fibres of the paper pulp mat providing inefficient hotspots).

The cellulosic fibres of the paper pulp mat 110 may be a cellulosic fibre mixture of first fibres and second fibres, respectively having a shorter and a longer average fibre length. At least 70%wt of the cellulosic fibres within the paper pulp mat 110 may have a fibre length within either a first length range of 3mm to 8mm or within a second length range of 10mm to 15mm (e.g. at least 80%wt or at least 90%wt of the fibres are within both the first and second ranges). At least 70%wt of the first fibres may have a fibre length range of 3mm to 8mm. At least 70%wt of the second fibres may have a second fibre length range of 10mm to 15mm.

Within the paper pulp mat 110, the mixture of first fibres having a shorter average length and second fibres having a longer average length enhances performance over a paper pulp mat formed from only one of the first or the second fibres. The cellulosic fibre mixture may comprise at least 20%wt of fibres having lengths within the first fibre length, and at least 20%wt of fibres having lengths within the second fibre length range.

The average percentage (by mass) of fibres per millimetre of a fibre length range may be described as the "average fibre length frequency". For example, if 40%wt of the fibres within the fibre mixture fall within the fibre length range 3mm to 8mm (first fibre length range), the average fibre length frequency within the first fibre length range would be 8%wt/mm.

Between the first and second fibre length ranges, there is an intermediary length range (e.g. between 8mm and 10mm). The average fibre length frequency within the intermediary length range may be lower than the average fibre length frequency within each of the first and second fibre length ranges. The average fibre length frequency within the intermediary length range may be at least 30% lower than the average fibre length frequency within each of the first and second fibre length ranges.

Within the fibre mixture, the second fibres, which have the longer average length, provide resilience to the paper pulp mat 110, which reduces compression in use, helping to keep the sheet paper layers 120 apart, which maintains the thermal insulation performance of the thermally insulating packaging 100, 100' and 100". In contrast, a paper pulp mat 110 having fewer second fibres would form a more densely packed paper pulp mat, with a reduced proportion of micro-pockets of air, which would be more susceptible to compression of the paper pulp mat.

Within the fibre mixture, the first fibres, which have the shorter average length, entrap micro-pockets of air within the paper pulp mat 110, reducing air flow through the paper pulp mat, which enhances the thermal insulation performance, in use.

The average length of the second fibres may be at least 50% greater than the average length of the first fibres, or may be at least 75% greater, or may be at least 100% greater.

In the assembled thermally insulating packaging 100, the paper pulp mat 110 may have a volumetric mass density of 20-50 kg/m', or 30-50 kg/m'. The paper pulp mat 110 within the assembled thermally insulating packaging 100 may have a volumetric mass density that is lower than the volumetric mass density of the sheet paper layers by at least 20%, or at least 30%.

The paper pulp mat 110 may have a thickness of at least 15mm, or at least 20mm. The thick paper pulp mat 110 provides a high level of thermal insulation. The paper pulp mat 110 may have thermal conductivity of 0.015 to 0.050 W/(m.K), or of 0.025 to 0.035 W/(m.K).

The areal mass density of the sheet paper layers 120 may be 40 to 100 g/m2. The volumetric mass density of the sheet paper layers 120 may be 500 to 1000 kg/m3, or 600 to 900 kg/m'. One or more of the sheet paper layers 120 may be able to absorb moisture, e.g. from condensation on thermally insulated products or ice packs, within use, whilst resisting transmission of moisture through the sheet paper layer to the paper pulp mat 110, so maintaining the thermal insulation performance of the paper pulp mat. The sheet paper layers 120 may be a light-weight kraft paper or paperboard (cardboard), which is more rigid that typical writing paper, whilst still able to flex and crease without fracture.

In the illustrated thermally insulating packaging 100, the paper pulp mat 110 has a volumetric mass density of 40 kg/m', and the sheet paper layers 120 have an areal mass density of 50 g/m2.

The adhesive (for example: the first adhesive 130; or the first adhesive 130 and additionally one or both of the second adhesive 140 and a pattern of further adhesive 482, where present) may be less than 3%wt (% of the mass) of the thermally insulating packaging. Formation of the thermally insulating packaging 100, 100', 100" with less than 3%wt of adhesive typically enables the thermally insulating packaging to be recycled with domestic paper recycling.

The adhesive 130, 140 may be a holt melt glue, for example, ethylene-vinyl acetate (EVA) glue (e.g. ADMELT® 7591G from A.D. System Limited). The use of this adhesive may enable the manufacture of robust, thermally insulating packaging that resists water leakage and water penetration at the adhesive. The adhesive retains some flexible in use, to avoid cracking when the thermally insulating packaging is used with chilled goods.

The second adhesive 140 may be aligned with the first adhesive 130. Alternatively, the second adhesive 140 may be offset from the first adhesive, which may provide additional flexibility in the assembled thermally insulating packaging 100'.

Advantageously, by the use of paper and paper pulp that is substantially cellulosic, with less than 3%wt of adhesive, the assembled thermally insulating package may be recycled through domestic paper recycling or composting, providing a lower environmental of footprint than existing rPET thermally insulating packaging, both in manufacturing and in end of life disposal.

Figure 1F shows thermally insulating packaging 100" (e.g. a thermally insulating bag) of Figure 1C, in use with exemplary chilled foodstuffs 190 and an ice pack 192. The section indicated by line D-D corresponds with the cross-sectional view of Figure 1D.

In use, chilled goods 190 (e.g. foodstuffs, horticultural products, pharmaceuticals, chemical reagents) are placed into the thermally insulating package, e.g. with ice packs 192 to assist with regulating the temperature of the chilled goods. Condensation may develop on the exterior of chilled goods and any ice packs. The sheet paper layer 120 provides a moisture barrier that protects the paper pulp mat 110 from moisture damage, when the thermally insulating package is in use. The volumetric mass density of the sheet paper layer provides a fibre structure that may be sufficiently tightly packed to resist penetration by moisture, during use (e.g. 24 to 48 hours), e.g. relative to a thicker paper with the same areal mass density. For a given thickness, sheet paper layers 120 with a higher areal mass density may resist penetration by moisture for longer. The sheet paper layer 120 may absorb some condensation to prevent the moisture passing into the paper pulp mat 110.

The exterior sheet paper layer 120 of the thermally insulating package may be provided with a moisture resistant coating (e.g. the sheet paper layer may comprise wax or polyethylene (PE), e.g. less than 5%wt of wax or PE), to resist transfer of moisture from the thermally insulating package to a transport box (e.g. cardboard) in which it is packed. Additionally, the heavier-weight sheet paper 120 layer protects the paper pulp mat 110 from mechanical damage, in use.

The use of the protective sheet paper layer 120 enables the selection of a lighter paper pulp mat 110, which may have a greater thermal insulation, flexibility and elasticity, and enables the use of a lower total weight of layers of the thermally insulating packaging to provide a given level of thermal insulation.

The paper pulp mat 110 may be formed from airlaid cellulosic fibres 112, which may be formed from milled paper or paperboard (cardboard), for example recycled paper or paperboard.

The cellulosic paper pulp fibres 112 for forming the paper pulp mat 110 may be produced by feeding virgin or recycled cellulosic material, such as paper or cardboard, into a hammer mill, where hammers are spun at high-speed and impact the cellulosic material, breaking apart the structure into fibres, pieces of material and fine dust-like material. The cellulosic material may be cut into pieces before being fed into the hammer mill.

A hole screen (e.g. a metal hole screen), for the passage of fibres, may be used to separate milled fibres and fine particulate from larger pieces of material. The hole screen has a large number of holes, and may have a mixture of first holes and second holes, respectively having a smaller and a larger maximum dimension (e.g. diameter), for passing the first fibres and second fibres. The first and second holes may be provided in different regions of the hole screen, or the first and second holes may be inter-mixed on the hole screen, for example, a hole screen 248 having alternating rows of first holes 248A and second holes 248B, as shown in Figure 2A. Alternatively, the first and second holes may be provided on separate hole screens, enabling the respectively passed fibres to be subjected to different filtering processes, before combination.

The first holes have a maximum dimension (e.g. diameter) of 9mm to 13mm, or may have a maximum dimension 10mm to 12mm, e.g. having a maximum dimension of 11mm. The first holes may pass fibres mostly in the length range 3mm to 8mm. Smaller holes than the first holes would reduce the fibre length too far and increase the proportion (by mass) of dust that passes through the screen, increasing the complexity of a subsequent fine filtering stage. The second holes may have a maximum dimension (e.g. diameter) of 13mm to 17mm, or may have a maximum dimension of 14mm to 16mm, e.g. having a maximum dimension of 15mm. The second holes may pass fibres mostly in the length range of 10mm to 15mm. Larger holes than the second holes would allow clumps of paper/carboard to pass through.

Finer, dust-like particulate is removed from the passed material by separation with a fine filter, producing a feedstock in which at least 70c/owt of the fibres passed by the first holes may have a fibre length range of 3mm to 8mm (e.g. being the first fibres of the paper pulp mat 110), and at least 70%wt of the fibres may have a second fibre length range of 10mm to 15mm (e.g. being the second fibres of the paper pulp mat). The relative numbers of first and second holes in the hole screen may be selected to provide a mixture of fibre lengths in which at least 20%wt of passed fibres have the first fibre length, and at least 20%wt of passed fibres have the second fibre length range.

The cellulosic fibres 112 may be deposited through an airlaying tower 250, for example by allowing the fibres to deposit onto a mesh conveyor belt 260 with low pressure air flowing down through the mesh (e.g. a gentle air flow may be provided to blow the fibres 112 through the airlaying tower 250, and onto the conveyor belt 260). Deposition of the fibres 112 under a low pressure air flow enables a paper pulp layer 116 to be built-up with a low density (i.e. enhanced "loft") by the incorporation of micro-pockets of air. The paper pulp layer 116 is cut C into separate paper pulp mats 110, as shown in Figure 2B, before assembly between the sheet paper layers 120 Before passing into the airlaying tower for deposition, the milled fibres may be dampened, to provide fibres having a mean average of 5 to 8%vvt water (when assembled into the thermally insulating packaging 100). For example, the fibres may be dampened by spraying with water as they are spun through a vortex sprayer, not shown, which produces a relatively uniform coating onto the exterior of the fibres, producing corresponding dampening of the fibre. Dampness in this range enhances mechanical bonding of the deposited cellulosic fibres, when forming the paper pulp layer 116. In contrast, a greater proportion (by mass) of water may produce a more dense paper pulp layer, and may be susceptible to the growth of mould or bacterial within the assembled thermally insulating packaging.

Figure 2B also illustrates a deposition process, in which the moistened paper pulp fibres 112 are blown into the air laying tower 250, and deposited onto a mesh conveyor belt 260. There may be a small amount of suction that gently draws the fibres 112 towards the conveyor belt 260 to aid in the speed of settling. The dampened fibres 112 may clump together 114 which would increase the density and reduce the thermal insulation of the deposited layer. To address this, the fibre clumps 114 may be passed through a plurality of rotating spiked rollers 252 that break up the fibre clumps 114 prior to deposition onto the conveyor belt 260.

The described air laying process 200 enables the paper pulp layer 116 to be formed with a higher proportion of air pockets, which trap air in the structure and improve the thermal performance of the thermally insulating packaging, by reducing conduction and convection through the paper pulp mat 110, in use.

After deposition, and cutting into separate airlaid paper pulp mats 110, the mats are provided with facing sheet paper layers 120, e.g. from rolls of sheet paper 122, to form a three layer structure, as shown in Figure 2B.

As shown in Figure 2C, the paper pulp mats 110 (or the uncut paper pulp layer 116) may be gently compressed (e.g. by passage between compression rollers 270) to enhance bonding between the dampened cellulosic fibres 112 (e.g. by hydrogen bonding between the dampened surfaces of the fibres, where they are in physical contact), providing a paper pulp layer 116 (from which the paper pulp mat 110 is cut) that is more resilient both during manufacture and when the thermally insulating packaging is in use. The paper pulp layer 110 may be compressed by up to 60% of the pre-compressed thickness TO of the paper pulp mat 110. The compressed paper pulp mat 110' may be compressed to a thickness TC that is 50-67% of the deposited thickness TD. Although Figure 2C shows the separate paper pulp mats 110 being compressed between the sheet paper layers 120, alternatively the paper pulp layer 116 may be compressed before being cut into separate paper pulp mats and assembled between the sheet paper layers.

Figures 1A-1E show thermally insulating packaging 100, 100', 100", in which the first and second adhesives 130, 140 are each provided as continuous strips of adhesive extending along within a margin M around the paper pulp mat 110. Alternatively, the adhesive 330, 340 in the thermally insulating packaging 300, 300' may be provided as an intermittent pattern of adhesive extending along within the margin M around the paper pulp mat 310, as shown in the thermally insulating packaging (wrap) 400 in Figure 3A and the thermally insulating packaging (bag or pounch) 400' in Figure 3B, which otherwise correspond with the thermally insulating packaging 300, 300' of Figures 1B and 1C. For example, the intermittent pattern of adhesive may be lines of dots of adhesive that are spaced apart. For example, the dots may be provided as 5mm diameter dots of adhesive at 20mm intervals, which are compressed to 8-9mm dots, during assembly of the thermally insulating packaging (Figures 3A and 3B show the dots of adhesive as applied to the lower sheet paper layer 120, before being compressed, during assembly). The provision of small gaps in the intermittent pattern of adhesive provides enhanced flexibility of the thermally insulating packaging, whilst substantially preventing the loss of fibres from the paper pulp mat 310 in use.

A pattern of (further) adhesive 482 may be provided on the face of a sheet paper layer 420 (or on both sheet paper layers), that faces the paper pulp mat 410 in the assembled thermally insulating packaging 400, as shown in Figures 4A and 4B (which otherwise correspond with Figures 1A and 1B). The pattern of adhesive 482 may be a plurality of lines of adhesive (e.g. at least 2, at least 3 or at least 5 lines) that extend along the sheet paper layer 420. During assembly of the thermally insulating packaging 400, the pattern of adhesive 482 may be provided by dispensing adhesive onto the sheet paper layer 420 before the paper pulp mat 410 is provided upon it, e.g. being provided by a row of adhesive dispensers 480, as shown in side and end view in Figures 40 and 40. The pattern of adhesive 482 may be sufficiently tacky to grip the paper pulp mat 410, where they are in contact.

The pattern of adhesive 482, on an internal face of the sheet paper layer 420, resists movement of the paper pulp mat 410 within the assembled thermally insulating packaging 400, in use, which may lead to the paper pulp mat 410 becoming compressed to one end within the thermally insulating packaging, reducing the thermal insulation performance elsewhere.

Although the thermally insulating packaging 400 is shown as a thermally insulating wrap in Figures 4A and 4B, the thermally insulating packaging may alternatively be formed as a thermally insulating bag (pouch), similarly to those illustrated in Figures 10 to 1F.

The thermally insulating packaging has mainly been described for use in maintaining the temperature of chilled product. However, the thermally insulating packaging may also be used in maintaining the temperature of heated products, e.g. takeaway (takeout) food products.

The figures provided herein are schematic and not to scale.

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

Claims

CLAIMS1. Thermally insulating packaging (100, 100', 100") comprising a cellulosic paper pulp mat (110) between first and second cellulosic sheet paper layers (120), wherein the first and second sheet paper layers (120) extend into a margin (M) around the paper pulp mat (110) and first adhesive bonds together the first and second sheet paper layers (120) within the margin (M).
2. The thermally insulating packaging of claim 1, wherein the paper pulp mat has a thickness of at least 15mm.
3. The thermally insulating packaging of claim 1 or claim 2, wherein at least 70%wt of the fibres within the cellulosic paper pulp mat (110) have fibre lengths of 3 to 15 mm.
4. The thermally insulating packaging of any one of claims 1, 2 or 3, wherein the cellulosic fibres within the cellulosic paper pulp mat (110) comprises a mixture of first fibres and second fibres, wherein the average length of the second fibres is longer than the average length of the first fibres.
5. The thermally insulating packaging of claim 4, wherein at least 70%wt of the cellulosic fibres within the paper pulp mat (110) have a fibre length within either a first fibre length range of 3mm to 8mm or within a second fibre length range of 10mm to 15mm.
6. The thermally insulating packaging of claim 5, wherein an average fibre length frequency within an intermediary fibre length range of between 8mm and 10mm is lower than the average fibre length frequency within each of the first and second fibre length ranges.
7. The thermally insulating packaging of any preceding claim, wherein the cellulosic paper pulp comprises 5°/owt to 8%wt water.
8. The thermally insulating packaging of any preceding claim, wherein the volumetric mass density of the cellulosic paper pulp in the paper pulp mat (110) is within the range 20 to 50 kg/m2.
9. The thermally insulating packaging of any preceding claim, wherein the cellulosic sheet paper has an areal mass density of 40 to 100 g/m2.
10. The thermally insulating packaging of any preceding claim, wherein at least one of the cellulosic paper layers is provided with a waterproof coating.
11. The thermally insulating packaging of any preceding claim, wherein the thermally insulating packaging is folded (F) and secured in a folded configuration by bonding with a second adhesive (140) within the margin (M).
12. The thermally insulating packaging of any preceding claim, wherein the first adhesive (330) and any second adhesive (340) is provided as an intermittent pattern of adhesive extending along the margin (M).
13. The thermally insulating packaging of any preceding claim, wherein a patterned further adhesive (482) is provided on an face of a sheet paper layer (420) facing towards the paper pulp mat (410).
14. A method of manufacturing thermally insulating packaging comprising: providing an arrangement of a cellulosic paper pulp mat (110) between first and second cellulosic paper layers (120), wherein the first and second sheet paper layers (120) extend into a margin (M) around the paper pulp mat (110); and bonding together the first and second sheet paper layers (120) within the margin (M) with a first adhesive (130).
15. The method of claim 14, comprising air laying cellulosic fibres (112) to form a paper pulp layer (116) from which the paper pulp mat (110) is cut.
16. The method of claim 15, comprising dampening the cellulosic fibres (112) to comprise 5 to 8%wt of water before air laying.
17. The method of claim 17 or claim 18, comprising passing the cellulosic fibres (112) through a plurality of rotating spiked rollers (252) before deposition onto a conveyor belt (260) to form the paper pulp layer (116).
18. The method of any of claims 15 to 17, comprising compressing the paper pulp layer (116) or paper pulp mat (110) before providing the cellulosic paper pulp mat (110) between first and second cellulosic paper layers (120).
19. The method of any one of claims 15 to 18, wherein the cellulosic fibres are formed by milling paper or cardboard with a hammer mill.
20. The method of claim 19, wherein the milled paper or carboard is separated by at least one hole screen having first holes and second holes, wherein the second holes are larger than the first holes.
21. The method of claim 20, wherein the first holes have a maximum dimension of 9mm to 13mm and the second holes have a maximum dimension of 13mm to 17mm.
22. The method of any one of claims 15 to 21, comprising folding (F) the thermally insulating packaging and bonding with a second adhesive (140) to retain the thermally insulating packaging in a folded configuration.
23. The method of any one of claims 15 to 22, wherein the first adhesive (330) and any second adhesive (340) is provided as an intermittent pattern of adhesive extending along the margin (M).
24. The method of any one of claims 15 to 23, comprising applying a patterned further adhesive (482) to a face of a sheet paper layer (420) for gripping the paper pulp mat (410) within the thermally insulating packaging (400).