Material for packaging

Abstract

Disclosed is a composite material for packaging, preferably a plastic free composite material, comprising a paper-based substrate; a layer of cellulose fibres on the substrate; a layer of inorganic material on the layer of cellulose fibres; and a sealing layer on the layer of inorganic material, wherein the sealing layer comprises a polymeric material derivable from natural sources. The use of the composite material for preparing packaging, packaging comprising the composite material, and a method of manufacturing a composite material for packaging is also described.

Description

[0001] MATERIAL FOR PACKAGING

[0002] INTRODUCTION

[0003] The invention relates to the field of packaging. Specifically, the invention relates to a composite material for packaging. The use of the composite material for preparing packaging, packaging comprising the composite material, and a method of manufacturing a composite material for packaging is also described.

[0004] BACKGROUND

[0005] Packaging is widely used to protect products (e.g. food products) while they are being transported and sold to consumers. The packaging provides a barrier layer that reduce the likelihood of the product spoiling over time, thereby providing a shelf stable product. For example, effective packaging can keep a product safe and secure from the harmful effects caused by exposure to oxygen and moisture.

[0006] Known packaging materials typically comprise multiple layers of material that are designed to provide desirable oxygen and moisture permeation properties. However, known packaging materials typically use one or more plastic-based materials in their composition. While plastic based materials often show highly desirable barrier properties, they have come under scrutiny in recent years due to the inherent difficulties in recycling the materials after use and the environmental impacts arising from their slow decomposition rates.

[0007] Accordingly there is need to develop new packaging materials that can provide desirable barrier properties while being constructed out of natural, or at least plastic-free, materials.

[0008] SUMMARY OF INVENTION

[0009] In an aspect of the invention there is provided a composite material for packaging, preferably a plastic free composite material, comprising: a paper-based substrate; a layer of cellulose fibres on the substrate; a layer of inorganic material on the layer of cellulose fibres; and a sealing layer on the layer of inorganic material, wherein the sealing layer comprises a polymeric material derivable from natural sources. In a further aspect of the invention there is provided a method of making a composite material for packaging, preferably a plastic free composite material, comprising: applying a layer of cellulose fibers to a paper-based substrate; applying an inorganic material on the layer of cellulose; and applying a sealing layer on the inorganic barrier material, wherein the sealing layer comprises of a polymeric material that is derivable from natural sources.

[0010] The invention also relates to packaging comprising the composite material

[0011] The invention also relates to the use of the composite material or preparing packaging.

[0012] DEFINTIONS

[0013] As used herein the term “composite material” refers to a material comprising two or more constituent materials. In this case, the composite materials comprises multiple layers of different materials.

[0014] As used herein the term “plastic free” refers to a material that does not comprise any synthetic organic polymers, e.g. polymers obtained from the deliberate polymerisation of monomers derived from crude oil. The only polymers present in a plastic free composite material are polymers that occur naturally, e.g. polymeric materials found in wood products, such as cellulose.

[0015] As used herein the term “paper-based substrate” refers to a substrate that is has been manufactured from the pulp of wood or other fibrous substances.

[0016] As used herein the term “inorganic material” refers to a layer of material that does not comprise any organic components, e.g. no organic polymers. The inorganic material may be an inorganic barrier material, e.g. an inorganic material that provides resistance to the permeation of either moisture or oxygen. The inorganic material may be an inorganic moisture barrier material, i.e. provides resistance to the permeation of at least moisture.

[0017] As used herein the term “sealing layer” refers to a layer applied to the surface of inorganic material that the covers the inorganic material and provides protection from external influences, such as moisture, oxygen, chemicals, abrasion or UV radiation.

[0018] As used herein the term “polymeric material derivable from natural sources” refers to a polymer that can be obtained from the processing natural products, such as trees, plants or crops. As used herein the term “polymeric material derivable from wood” refers to a polymer that can be obtained from the processing of a wood product, such as wood chips. The polymers are natural polymers such as lignin and hemicelluloses.

[0019] The term “paper grammage” is a term of the art and is intended to be given its normal interpretation. For example, it refers to weight of a layer per given area. It has units of grams per square metre. The paper grammage, also referred to as paper weight, is an indication of the thickness of the layer.

[0020] As used herein the term “nanofibres” refers to fibres having a diameters in the nanometer range, i.e. dimeters of 1 to 500 nm. Typically fiber size is determined by SEM measurements.

[0021] As used herein the term “nanoparticles” refers a particles having an average diameter of 1 to 100 nm. Typically particle size is determined by laser diffraction.

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] As discussed above, in an aspect of the invention there is provided a composite material for packaging, preferably a plastic free composite material, comprising: a paper-based substrate; a layer of cellulose fibres on the substrate; a layer of inorganic material on the layer of cellulose fibres; and a sealing layer on the layer of inorganic material, wherein the sealing layer comprises a polymeric material derivable from natural sources.

[0024] In general, the present invention proposes a new layered material that is designed to provide desirable protection to a product without relying on the use of any synthetic polymers. Advantageously, this can provide a packing system that allows the product to have an extended shelf life but can easily be recycled, and / or will naturally decompose, once it has been used. This reduces the environmental impact of the packaging compared to known plastic based packaging systems.

[0025] Without wishing to be bound by theory, it is believed that by using the specific combination of the layers described above, beneficial oxygen and moisture permeation properties can be provided without the need for any plastic materials. The combination of layers may also provide improved results compared to other plastic free packaging solutions.

[0026] Embodiments of the various aspects of the invention are described below. For the avoidance of doubt, it will be appreciated, where appropriate, that any embodiments as described herein in relation to one aspect of the present invention will also apply to the other aspects of the present invention, where appropriate.

[0027] Substrate

[0028] The substrate is paper-based. Preferably the substrate is cardboard or paper. Most preferably the substrate is paper.

[0029] Preferably the paper has a paper grammage of from 40 gsm to 140 gsm. More preferably the paper has a paper grammage of from 65 gsm to 100 gsm.

[0030] The paper may have a paper grammage of from 60 gsm to 80 gsm. The paper may have a paper grammage of from 80 gsm to 100 gsm. The paper may have a paper grammage of from 65 gsm to 70 gsm. The paper may have a paper grammage of from 70 gsm to 80 gsm. The paper may have a paper grammage of from 75 gsm to 85 gsm. The paper may have a paper grammage of from 80 gsm to 90 gsm. The paper may have a paper grammage of from 85 gsm to 95 gsm. The paper may have a paper grammage of from 90 gsm to 100 gsm. The paper may have a paper grammage of from 95 gsm to 105 gsm. The paper may have a paper grammage of from 60 gsm to 80 gsm.

[0031] The paper may have a thickness of from 70 pm to 150 pm.

[0032] Cellulose layer

[0033] The composite material comprises a layer of cellulose fibres

[0034] Preferably the cellulose fibres are cellulose nanofibers, i.e. the layer of cellulose fibres may comprise, preferably consist of, cellulose nanofibres.

[0035] Preferably the nanofibers have a mean diameter of from 1 to 100 nm. The nanofibers may have a mean diameter of from 5 to 100 nm. The nanofibers may have a mean diameter of from 5 to 50 nm. The nanofibers may have a mean diameter of from 10 to 50 nm. The nanofibers may have a mean diameter of from 5 to 20 nm. The nanofibers may have a mean diameter of from 10 to 30 nm.

[0036] Preferably the nanofibers have a mean length (i.e. the length of their longest dimension) of from 100 nm to 20 pm. The nanofibers may have a mean length of from 500 nm to 20 pm. The nanofibers may have a mean length of from 1 pm to 10 pm. The nanofibers may have a mean length of from 1 pm to 5 pm.

[0037] Preferably the layer of cellulose fibres has an oxygen transmission rate of from 0.1 to 20 cc / m2per day. Further preferably the layer of cellulose fibres has an oxygen transmission rate of preferably from 0.1 to 5 cc / m2per day. The oxygen transmission rate may be measured according to ASTM standard D3985. Preferably the layer of cellulose fibres has a paper grammage of from 2 gsm to

[0038] 80 gsm. More preferably the layer of cellulose fibres has a paper grammage of from 5 gsm to 50 gsm. Further preferably the layer of cellulose fibres has a paper grammage of from 5 gsm to 30 gsm.

[0039] The layer of cellulose fibres may have a paper grammage of from 5 gsm to 30 gsm. The layer of cellulose fibres may have a paper grammage of from 10 gsm to 25 gsm. The layer of cellulose fibres may have a paper grammage of from 15 gsm to 20 gsm. The layer of cellulose fibres may have a paper grammage of from 15 gsm to 30 gsm. The layer of cellulose fibres may have a paper grammage of from 15 gsm to 25 gsm. The layer of cellulose fibres may have a paper grammage of from 10 gsm to 20 gsm. The layer of cellulose fibres may have a paper grammage of from 5 gsm to 15 gsm. The layer of cellulose fibres may have a paper grammage of from 5 gsm to 10 gsm.

[0040] The layer of cellulose fibres may have a thickness of from 5 pm to 50 pm. The layer of cellulose fibres may have a thickness of from 10 pm to 40 pm.

[0041] Inorganic material

[0042] As specified above, the inorganic material may be an inorganic barrier material. The inorganic material may be an inorganic moisture barrier material.

[0043] Preferably, the inorganic material is selected from a silicon oxide, a metal, an aluminium oxide, or combinations thereof.

[0044] The inorganic barrier material may comprise a silicon oxide. The inorganic barrier material may be expressed by the formula SiOx, where 0 < x < 2, preferably 1 < x < 2. The inorganic barrier material may be a silicon dioxide.

[0045] The inorganic barrier material may comprise an aluminium oxide. The inorganic barrier material may be expressed by the formula AIOX, where 0 < x < 1 .5. The inorganic barrier material may be AI2O3.

[0046] The inorganic barrier material may be a metal, i.e. a metallic layer, typically formed by metallization. The metal may be aluminium.

[0047] Preferably the layer of inorganic material has a water vapour transmission rate of 0.01 to 5 g / m2per day. The layer of inorganic material may have a water vapour transmission rate of 0.1 to 5 g / m2per day. The layer of inorganic material may have a water vapour transmission rate of 0.01 to 1 g / m2per day. The layer of inorganic material may have a water vapour transmission rate of 0.05 to 2 g / m2per day. The water vapour transmission rate may be measured in accordance to ASTM D1434. Preferably the layer of inorganic material has a thickness of from 5 nm to 50 nm. The layer of inorganic material may have a thickness of from 10 nm to 45 nm. The layer of inorganic material may have a thickness of from 15 nm to 40 nm. The layer of inorganic material may have a thickness of from 20 nm to 35 nm. The layer of inorganic material may have a thickness of from 5 nm to 30 nm. The layer of inorganic material may have a thickness of from 20 nm to 50 nm.

[0048] Sealing layer

[0049] The composite materials comprises a sealing layer comprising a polymeric material derivable from natural sources.

[0050] The polymer derivable from natural sources may be a polymeric material derivable from wood.

[0051] The polymeric material derivable from wood may be selected from lignin, hemicellulose, cellophane, or combinations thereof.

[0052] The polymeric material derivable from wood may be hemicellulose. The polymeric material derivable from wood may be cellophane. Preferably the polymeric material derivable from wood is lignin.

[0053] The polymer derivable from natural sources may be a gum.

[0054] The polymer derivable from natural sources may be a rubber.

[0055] The polymer derivable from natural sources may be a polysaccharide. Preferably the polysaccharide is starch.

[0056] The polymer derivable from natural sources may be a vegetable wax.

[0057] The polymer derivable from natural sources may be selected from lignin, hemicellulose, cellophane and starch

[0058] Preferably the polymer derivable from natural sources is not cellulose fibers (i.e. it is different to the layer of cellulose fibres).

[0059] The sealing layer may comprise nanoparticles of the polymeric material derivable from wood (e.g. nanoparticles of lignin).

[0060] Preferably the sealing layer has a paper grammage of from 2 gsm to 50 gsm. More preferably the sealing layer has a paper grammage of from 5 gsm to 50 gsm. Further preferably the sealing layer has a paper grammage of from 5 gsm to 15 gsm.

[0061] The sealing layer may have a paper grammage of from 10 gsm to 40 gsm. The sealing layer may have a paper grammage of from 10 gsm to 30 gsm. The sealing layer may have a paper grammage of from 5 gsm to 20 gsm. The sealing layer may have a paper grammage of from 10 gsm to 20 gsm. The sealing layer may have a paper grammage of from 5 gsm to 10 gsm. The sealing layer may have a paper grammage of from 10 gsm to 15 gsm. The sealing layer may have a paper grammage of from 10 gsm to 20 gsm. The sealing layer may have a paper grammage of from 15 gsm to 20 gsm. The sealing layer may have a paper grammage of from 20 gsm to 25 gsm.

[0062] The sealing layer may have a paper grammage of from 2 gsm to 10 gsm. The sealing layer may have a paper grammage of from 4 gsm to 8 gsm. The sealing layer may have a paper grammage of from 5 gsm to 10 gsm. The sealing layer may have a paper grammage of from 8 gsm to 12 gsm. The sealing layer may have a paper grammage of from 9 gsm to 11 gsm.

[0063] The sealing layer may have a thickness of from 5 pm to 50 pm. The sealing layer may have a thickness of from 10 pm to 40 pm. The sealing layer may have a thickness of from 5 pm to 30 pm. The sealing layer may have a thickness of from 10 pm to 30 pm.

[0064] Relative thickness of the layers

[0065] Preferably the ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the sealing layer is from 5:1 to 1 :5, more preferably 2:1 to 1 :2. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the sealing layer may be 3:1 to 1 :3. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the sealing layer may be 1.5:1 to 1 :1.5. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the sealing layer may be 1 :1 to 1 :2. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the sealing layer may be 2:1 to 1 :2.

[0066] Preferably the ratio of the paper grammage of the sealing layer to the thickness of the substrate is from 1 :20 to 1 :1 . The ratio of the paper grammage of the sealing layer to the thickness of the substrate may be from 1 :20 to 1 :2. The ratio of the paper grammage of the sealing layer to the paper grammage of the substrate may be from 1 :20 to 1 :4. The ratio of the paper grammage of the sealing layer to the paper grammage of the substrate may be from 1 :10 to 1 :2. The ratio of the paper grammage of the sealing layer to the paper grammage of the substrate may be from 1 :8 to 1 :4.

[0067] Preferably the ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the substrate is from 1 :20 to 1 :1. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the substrate may be from 1 :20 to 1 :2. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the substrate may be from 1 :20 to 1 :4. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the substrate may be from 1 :10 to 1 :2. The ratio of the paper grammage of the layer of cellulose fibers to the paper grammage of the substrate may be from 1 :6 to 1 :3.

[0068] Preferably the ratio of the thickness (e.g. in pm) of the layer of cellulose fibers to the thickness of the sealing layer is from 5:1 to 1 :5, more preferably 2:1 to 1 :2. The ratio of the thickness of the layer of cellulose fibers to the thickness of the sealing layer may be 3: 1 to 1 :3. The ratio of the thickness of the layer of cellulose fibers to the thickness of the sealing layer may be 1.5:1 to 1 :1.5. The ratio of the thickness of the layer of cellulose fibers to the thickness of the sealing layer may be 1 :1 to 1 :2. The ratio of the thickness of the layer of cellulose fibers to the thickness of the sealing layer may be 2:1 to 1 :2.

[0069] Preferably the ratio of the thickness (e.g. in pm) of the sealing layer to the thickness of the substrate is from 1 :20 to 1 :1. The ratio of the thickness of the sealing layer to the thickness of the substrate may be from 1 :20 to 1 :2. The ratio of the thickness of the sealing layer to the thickness of the substrate may be from 1 :20 to 1 :4. The ratio of the thickness of the sealing layer to the thickness of the substrate may be from 1 :10 to 1 :2. The ratio of the thickness of the sealing layer to the thickness of the substrate may be from 1 :8 to 1 :4.

[0070] Preferably the ratio of the thickness (e.g. in pm) of the layer of cellulose fibers to the thickness of the substrate is from 1 :20 to 1 :1. The ratio of the thickness of the layer of cellulose fibers to the thickness of the substrate may be from 1 :20 to 1 :2. The ratio of the thickness of the layer of cellulose fibers to the thickness of the substrate may be from 1 :20 to 1 :4. The ratio of the thickness of the layer of cellulose fibers to the thickness of the substrate may be from 1 :10 to 1 :2. The ratio of the thickness of the layer of cellulose fibers to the thickness of the substrate may be from 1 :6 to 1 :3.

[0071] Overall composite material

[0072] Preferably the composite material does not comprise any plastic (i.e. it is plastic free). Preferably the only polymers in the composite material are polymers that are derivable (or derived) from natural sources. Preferably the only polymers in the composite material are polymers that are derivable (or derived) from wood. Preferably the composite material is 100% paper based except for the layer of inorganic material.

[0073] Method of manufacture

[0074] As discussed above, in an aspect of the invention there is provided a method of making a composite material for packaging, preferably a plastic free composite material, comprising: applying a layer of cellulose fibers to a paper-based substrate; applying an inorganic material on the layer of cellulose; and applying a sealing layer on the inorganic material, wherein the sealing layer comprises of a polymeric material that is derivable from natural sources.

[0075] It will be appreciated that the steps of this method could occur in any order as long as each layers are applied to its correct layer. For example, the packaging could be manufactured layer-by-layer starting from the substrate, i.e. substrate first, then cellulose fibers, then inorganic material, and then sealing layer. Alternatively, two or more layers could be added together before addition to the substrate, or to another layer. For example, the inorganic material could first be applied to the cellulose fibres and then both layers could be applied to the substrate. The sealing layer would then finally be is applied to the inorganic material to provide the overall composite material.

[0076] It will also be appreciated that the various layers may be the layers described in the sections above. Analogously, the layers may be applied in a manner that provides the thickness and / or paper grammage levels described above.

[0077] The layer cellulose fibers (or nanofibers) could be obtained from treatment of wood. Accordingly the method may further comprise obtaining cellulose fibres, preferably from the treatment of wood; and exposing the cellulose fibres to an enzyme and / or mechanical shearing to obtain cellulose nanofibres.

[0078] The layer of cellulose fibers (or nanofibers) could be applied to the paper-based substrate using a bar coating, slot-die coating, curtain, gravure or rotogravure.

[0079] The sealing layer could be applied as a film or as a dispersion.

[0080] The sealing layer could be applied by adhesive lamination, lamination or gravure coating.

[0081] The polymeric material that is derivable from natural sources could be in the form of nanoparticles (e.g. lignin nanoparticles) when it is applied to the inorganic material. The sealing layer may then be subsequently treated to form a homogeneous and continuous layer.

[0082] In methods where the polymeric material derivable form natural sources is selected from lignin, hemicellulose, cellophane, or combinations thereof, the method may further comprise: extracting lignin, hemicellulose from wood, or extracting cellulose fibres from wood and processing them to form cellophane. Where the polymeric material derivable form natural sources is lignin, the method may further comprise sonicating the lignin to provide nanoparticles.

[0083] The method may further comprise fractionation of the lignin, wherein one or more fractions are then selected for sonication.

[0084] In some methods the cellulose fibres and the polymeric material derivable from wood are obtained from the same wood.

[0085] In such methods, the method may further comprise treating (e.g. bleaching) wood to obtain cellulose fibres and a liquor comprising lignin and / or hemicellulose; exposing the cellulose fibres to an enzyme and / or mechanical shearing to obtain cellulose nanofibers; and extracting lignin and / or hemicellulose from said liquor.

[0086] The method may also comprise sonicating the extracted lignin to provide nanoparticles.

[0087] Packaging

[0088] As mentioned, the invention also relates to packaging comprising the composite material and the use of the composite material in packaging. The packaging may be flexible or may rigid.

[0089] The packaging may, for example, be cups, pouches, trays or coffee capsules.

[0090] BRIEF DESCRIPTION OF FIGURES

[0091] Figure 1 shows a schematic of a composite material according to the present invention.

[0092] EXAMPLES

[0093] The materials used in the examples were all commercially available, unless otherwise stated.

[0094] Preparation of composite layer

[0095] In an example process for preparing a composite material according to the present invention, a 3wt% suspension of cellulose nanofibers in water is applied to a paper substrate via bar coating. This layer is then dried to remove the water and provide a layer of cellulose nanofibers. An inorganic barrier layer of silicon or aluminium oxide is then deposited on the cellulose nanofibers. Finally the sealing layer (e.g. a layer of lignin) is applied to the inorganic barrier material bar coating.An example composite material is shown in figure 1. The composite material 1 comprises a paper layer 10 with a paper weight of 65 to 100 gsm. Applied to the paper layer 10 is a layer of cellulose nanofibers 20 with a paper weight of 5 to 20 gsm. An inorganic barrier layer 30 comprising silicon or aluminium oxide is applied to the cellulose nanofibers, and a sealing layer (e.g. a layer of lignin) 40 with a paper weight of 5 to 15 gsm is applied to inorganic barrier layer creating a four layer structure.

Claims

CLAIMS:1 . A composite material for packaging, preferably a plastic free composite material, comprising: a paper-based substrate; a layer of cellulose fibres on the substrate; a layer of inorganic material on the layer of cellulose fibres; and a sealing layer on the layer of inorganic material, wherein the sealing layer comprises a polymeric material derivable from natural sources.

2. The material of claim 1 wherein the paper-based substrate is cardboard or paper, preferably paper3. The material of claim 2 wherein the paper-based substrate is paper with a paper grammage of from 65 gsm to 100 gsm.

4. The material of any preceding claim wherein the layer of cellulose fibres comprises, preferably consists of, cellulose nanofibres.

5. The material of claim 4 wherein the cellulose nanofibers have a mean diameter of from 5 to 100 nm and mean length of from 500 nm to 20 pm.

6. The material of any preceding claim, wherein the layer of cellulose fibres has an oxygen transmission rate of from 0.1 to 20 cc / m2per day, preferably from 0.1 to 5 cc / m2per day, measured according the ASTM standard D3985.

7. The material of any preceding claim wherein the layer of cellulose fibres has a grammage of from 5 gsm to 50 gsm, preferably from 5 to 30 gsm.

8. The material of any preceding claim wherein the inorganic material is selected from a silicon oxide, metal, an aluminium oxide, or combinations thereof.

9. The material of any preceding claim wherein the layer of inorganic material has a thickness of from 5 to 50 nm.

10. The material of any preceding claim, wherein the layer of inorganic material has a water vapor transmission rate of from 0.01 to 5 g / m2per day, measured according the ASTM D1434.11 . The material of any preceding claim wherein the polymer derivable from natural sources is a polymeric material derivable from wood, or is a gum, a rubber, a vegetable wax, or a polysaccharide.

12. The material of claim 11 wherein the polymer derivable from natural sources is a polymeric material derivable from wood, and is selected from lignin, hemicellulose, cellophane, or combinations thereof, preferably wherein the polymeric material derivable from wood is lignin.

13. The material of claim 11 wherein the polymeric material derivable from natural sources is a polysaccharide, preferably wherein the polysaccharide is starch.

14. The material of any preceding claim wherein the sealing layer has a paper grammage of from 5 gsm to 50 gsm, preferably of from 5gsm to 15 gsm.

15. The material of any preceding claim wherein the ratio of the thickness of the layer of cellulose fibers to the thickness of the sealing layer is from 5:1 to 1 :5, preferably 2:1 to 1 :2.

16. The material of any preceding claim wherein the ratio of the thickness of the sealing layer to the thickness of the substrate is from 1 :20 to 1 :4.

17. The material of any preceding claim wherein the composite material does not comprise any plastic.

18. A method of making a composite material for packaging, preferably a plastic free composite material, comprising: applying a layer of cellulose fibers, preferably cellulose nanofibers, to a paper-based substrate; applying an inorganic material on the layer of cellulose; and applying a sealing layer on the inorganic material,14 wherein the sealing layer comprises of a polymeric material that is derivable from natural sources.

19. The method of claim 18 wherein the polymeric material that is derivable from natural sources is applied as nanoparticles and subsequently treated to form a homogeneous and continuous layer.

20. The method of claims 18 or 19, further comprising obtaining cellulose fibres, preferably from the treatment of wood; and exposing the cellulose fibres to an enzyme and / or mechanical shearing to obtain cellulose nanofibres.

21. The method of any of claims 18 to 20 wherein the polymeric material derivable form natural source is a polymeric material derivable from wood and is selected from lignin, hemicellulose, cellophane, or combinations thereof.

22. The method of any of claims 18 to 21 , wherein said cellulose fibres and said polymeric material derivable from wood are obtained from the same wood.

23. The method as claimed in claim 22, comprising: treating (e.g. bleaching) wood to obtain cellulose fibres and a liquor comprising lignin and / or hemicellulose; exposing the cellulose fibres to an enzyme and / or mechanical shearing to obtain cellulose nanofibers; and extracting lignin and / or hemicellulose from said liquor.

24. Packaging comprising the composite material of any one of claims 1 to 17.

25. Use of the composite material of any one of claims 1 to 17 for preparing packaging.

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