GB2443810A

GB2443810A - Compostable packaging material

Info

Publication number: GB2443810A
Application number: GB0622679A
Authority: GB
Inventors: Stuart Henderson
Original assignee: Marks and Spencer PLC
Current assignee: Marks and Spencer PLC
Priority date: 2006-11-14
Filing date: 2006-11-14
Publication date: 2008-05-21
Also published as: GB0622679D0

Abstract

A packaging material comprises a compostable substrate 2, such as paperboard, provided with a surface film 6, also of compostable material, on an external surface of the substrate. The surface film is metallized (layer 12) and printed (layer 14) to provide a high-quality appearance to a package made from the packaging material. The surface film may be cellophane, polylactic acid, polyhydroxybutyric acid or polyhydroxylvaleric acid amongst numerous others mentioned. Lamination may be by means of a compostable adhesive 10. The packaging material may be in the form of a box or a tube of rectangular cross-section provided with end closure panels.

Description

-I

A PACKAGING MATERIAL

This invention relates to a packaging material, and is particularly, although not exclusively, concerned with a packaging material which is compostable but is suitable for use in the construction of packages having a high-quality printed external appearance.

In the context of the present invention, the expression ucompostable when applied to a material or a product means that the material, or the entire product, will both biodegrade and disintegrate. By "biodegrade" is meant that the chemical structure of the material breaks down under the action of micro-organisms, while by "disintegrates" is meant that the material, or the product made from it, will physically fall apart into fine visually indistinguishable fragments, at the end of a typical composting cycle. In order to be considered a compostable polymer material, the polymer chains must break down under the action of the micro-organisms, so that total minerailsation is achieved (ie conversion of the material into C02, water, Inorganic compounds and biomass under aerobic conditions) at a high rate compatible with the normal composting process of vegetable waste.

In particular, a material or product is considered to be compostable if it meets the requirements of STM 0533893 or ISO CD 14855.

For some time, pressure has been exerted for materials used in the packaging of products for retail sale to be recyclable, so that at least some of the components of the packaging can be recovered for re-use, or can be converted into useful materials for a secondary use. More recently, materials have been developed which are compostable, either in an industrial composting process or in smaller composting units as used by individual households.

For example, EP 0534471 discloses a composite laminate, for use in the manufacture of packaging containers, Which comprises a straight-chain, 3-hydroxybutyric acidl 3-hydroxyvaleric acid copolyester film laminated on a surface of a sheet-like substrate.

Also, US 5736204 discloses a paperboard container which is coated with a compostable material.

In practice, the use of compostable films in the packaging industry has been confined to the use of such films, for example of polylactic acid (PLA), as cover films provided over trays containing, for example, fruit and vegetable produce, or coated films on the inside of paperboard contains for liquids such as milk.

So far, it has been believed that the requirements for compostable packaging have been incompatible with a high-quality external appearance for a package, for use in packaging relatively high-value goods.

According to the present invention there is provided a packaging material comprising a compostable substrate in sheet form having, on an external surface, a metallised and printed surface film of a compostable polymer.

The substrate may comprise paperboard made from wood fibre or another cellulosic material.

It is envisaged that compostable polymers usable in the manufacture of a packaging material in accordance with the present invention will be so-called ubiopolymersN or bioplastics", for example non-oil-based polymers. Such polymers may be plant-based, for example cellulose-based, or they may be produced by fermentation processes, for example by the fermentation of sugars.

Examples of compostable polymers suitable for use as the metallised and printed surface film include thermoplastic oxyalkanoyl polymers, such as C-caprolactone polymers, beta propnolactone, &valerolactone, polyesters of 3-hydroxybutyric acid, 3-hydroxyvalenc acid and mixtures thereof as well as copolymers of any of the above.

Suitable also are graft polymers prepared by reacting a lactone such as -caprolactone with hydroxyl or amino functional resins such as hydrolyzed ethylene-vinyl acetate copolymers; segmented polyurethane prepared by reacting polycaprolactone bearing terminal hydroxyt groups with diisocyanates and, optionally, chain-extending glycots such as 1,4 butanediol.

Included also are aliphatic polyesters such as polyglycolic acid, polylactic acid (PLA), potydioxanone, poly(trimethylene carbonate) and their co-and terpolymers as well as blends of any of the above with polyesters prepared from alkanediols and alkanedicarboxylic acids including oxalates.

It is also possible to use polyhydroxyaliphatic acids (PHAA) or PHBV polymers which are polyesters of 3-hydroxybutyric (HB) and 3 hydroxyvaleric (HV) acids.

It is also possible to use cellophane and other cellulose-based materials.

The surface film may be applied to the substrate by any suitable technique, but preferably it is secured to the substrate in a lamination process. Thus, the surface film is initially manufactured as a separate film which is affixed to the substrate by means of a laminating adhesive. The laminating adhesive is preferably compostable. However, since the laminating adhesive will constitute only a very small part of the overall material, adequate compostability of the material as a whole may nevertheless be achieved even if a conventional, non-compostable, laminating adhesive is used.

The surface film may be metallised by a vacuum deposition process. In an embodiment of a material in accordance with the present invention, the metallisation may be applied to the surface of the surface film which, in the packaging material, faces towards the substrate. Thus, the nietallisation is situated between the substrate and the remainder of the surface film. The printing on the surface film may be applied after the film is affixed to the substrate.

In an embodiment of packaging material in accordance with the present invention, the internal surface of the material, ie the surface WhICh, when the packaging material is formed into a package, is situated on the inside of the package, may be uncoated, in that the surface of the material exposed to the inside of the package may be a surface of the substrate.

The present invention also provides a package formed from packaging material as defined above. The package may be in the form of a box or carton, which need not be liquid-tight. For example, the box or carton may be formed as a tube of rectangular cross-section having end closure panels which are folded inwardly to overlap one another, and which are fixed in position after the contents of the box or carton have been inserted. The end closure panels may be secured to one another by a suitable adhesive, for example a hot melt adhesive.

A box or carton in accordance with the present invention is particularly suitable for the packaging for retail sale of goods, of relatively high perceived value, for example premium biscuits, confectionery or other premium edible products such as Christmas puddings or the like. The box or carton is particularly suitable for dry goods, by which is meant goods which are not liquid or moist where they contact the interior of the box or carton. Thus, for example, bottled beverages, including alcoholic drinks, healthcare, beauty and gift cards may be packaged in a box or carton in accordance with the present invention.

For a better understanding of the present invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings, in which:-Figure 1 is a diagrammatic representation of a packaging material; and Figure 2 is a diagrammatic representation of packaging including the packaging material of Figure 1.

The packaging material shown in Figure 1 comprises a substrate 2 having an internal surface 4 and an external surface 6. In this context, the internal surface 4 is that surface which, in a container made from the packaging material, faces inwardly of the container, while the external surface 6 faces outwardly.

A surface film 8 is laminated to the substrate 2 by means of a laminating adhesive 10.

The substrate 2 comprises paperboard or carton board having the general characteristics of such board as typically used for cut and creased blanks for erection into boxes or cartons for packaging goods for retail sale. The substrate 2 is made from a compostable material, such as wood fibre.

The surface film 8 is also made from a compostable material, such as polylactic acid (PLA). In most embodiments in accordance with the present invention, the surface film is transparent, but includes a layer of metallisation 12, which is on the surface of the surface film directed towards the substrate 2. The metallisation may comprise aluminium applied by a vacuum deposition process, or any other material capable of providing a silvered appearance to the film 8.

The surface film 8 may be of any thickness suitable for lamination. It is envisaged that film thickness of 25 pm or less, more preferably 20 pm or less, will be suitable.

The external surface of the surface film 8, ie the surface directed away from the substrate 2, is printed, as indicated by a layer 14. with images or text appropriate to the product to be contained within the package made from the material. In an embodiment in accordance with the present invention, the printing may comprise high-quality multi- colour halftone images, for example produced in a four-colour printing process, so that the metallised surface film, in conjunction with the printing on its external surface provide a high-quality, premium appearance to the package made from the material.

In practice, the packaging material may be manufactured in the form of unprinted sheets comprising the substrate 2, to which the metallised surface film 8 is laminated.

Subsequently, the sheets are printed with the layer 14 and cut and creased to form individual blanks from which packaging containers are to be made.

An example of such a packaging container is shown in Figure 2, from which it will be appreciated that the package is in the form of a rectangular box erected from a printed blank of the material. The blank is folded to form a tube 16 of rectangular cross-section provided with end flaps and tabs 18, 20 which are hinged at the ends of the tube 16.

Goods 22 are then inserted into the formed tube 16 after which the flaps 18 and tabs are formed over the ends of the tube 16 and fixed to one another by a suitable adhesive to close the package.

It will be appreciated that, as shown in Figure 2, the goods within the package may be sealed within an inner wrapping, for example of a form-fill-seal wrapping of flexible material which may, itself, be made from a compostable polymeric film.

Such a package is suitable for dry edible goods such as biscuits, confectionery, etc which are contained within the inner wrapping 22 and so do not contact the internal surface of the packaging material. Consequently, the internal surface 4 of the substrate 2 can be the raw surface of the paperboard or other material of the substrate 2 without any applied coating. The lack of such a coating on the internal surface 4 enhances the compostability of the packaging material as a whole.

Alternatively, the package may be used for other types of goods, for example alcoholic beverages such as whisky and other spiiits, or wine. The package thus constitutes an additional layer of packaging over the bottie containing such beverages, healthcare and beauty products, to provide a premium appearance for the product.

Claims

1. A packaging material comprising a substrate of compostable material having, on an external surface, a metallised and printed surface film of a compostable polymer.

2. A packaging material as claimed in claim 1, in which the substrate comprises board made from wood fibre.

3. A packaging material as claimed in claim I or 2, in which the surface film comprises cellophane.

4. A packaging material as claimed in claim I or 2, in which the surface film comprises polylactic acid.

5. A packaging material as claimed in claim I or 2, in which the surface film comprises polyhydroxybutyric acid.

6. A packaging material as daimed in claim I or 2, in which the surface film comprises polyhydroxylvaleric acid.

7. A packaging material as claimed in any one of the preceding claims, in which the surface film is laminated to the substrate.

8. A packaging material as claimed in claim 7, in which the surface film is laminated to the substrate by a laminating adhesive which is compostable.

9. A packaging material as claimed in any one of the preceding claims, in which the surface film is metallised by a vacuum deposition process.

10. A packaging material as claimed in any one of the preceding claims, in which the surface film comprises a metallised layer on the surface of the surface film facing towards the substrate.

11. A packaging material as claimed in any one of the preceding claims, in which the surface film is printed on the surface of the film facing away from the substrate.

12. A packaging material as claimed in any one of the preceding claims, in which the internal surface of the substrate is uncoated.

13. A packaging material substantially as described herein, with reference to, and as shown in, Figure 1 of the accompanying drawings.

14. A package made from a packaging material in accordance with any one of the preceding claims.

15. A package as claimed in claim 14. which is in the form of a box.

16. A package as claimed in claim 14 or 15, which Is formed as a tube of rectangular cross-section provided with end closure panels.

17. A package as claimed in claim 16, in which the end closure panels are secured to one another by an adhesive.

18. A package as claimed in any one of daims 14 to 17, containing dry goods.

19. A package as claimed in any one of claims 14 to 18, in which the package comprises an outer container, the goods being contained within an inner container situated within the outer container.

20. A package substantially as described herein with reference to, and as shown in, the accompanying drawings.