GB2529904A

GB2529904A - Laminated structure

Info

Publication number: GB2529904A
Application number: GB1415857.0A
Authority: GB
Inventors: Stephen Langstaff
Original assignee: Innovia Films Ltd
Current assignee: Innovia Films Ltd
Priority date: 2014-09-08
Filing date: 2014-09-08
Publication date: 2016-03-09
Also published as: WO2016038350A1; GB201415857D0

Abstract

A laminated structure for use in barrier packaging, the structure comprising a first layer 1 providing oxygen barrier properties and at least one second layer 3 providing moisture barrier properties, wherein the first layer has an oxygen permeability of no more than 5 cm3/m2/day and a tensile stiffness in the machine direction of greater than about 2800 MPa, and the second layer has a water vapour transmission rate of no more than 10 g/m2/day. The preferred materials are cellulose or cellulose derivatives for the first layer and a polyolefin (e.g polyethylene, PE, LDPE, polypropylene, PP, or polybutylene, PB), most preferably LLDPE. The laminate may be formed from biodegradable and/or renewable and/or reclaimed material. The second layer may be a heat-sealable layer. The laminate may comprise a tie layer 2 between the first and the second layer, e.g. a maleic anhydride-substituted polyolefin. The laminate may be used in a barrier packaging of a tube-shaped container. Further layers may be added such as ink 4 and lacquer layers 5. The laminate is formed by extruding, co-extruding or laminating the first layer with the second layer.

Description

LAMINATED STRUCTURE

The present invention relates to laminated structures. In particular, the present invention r&ates to laminated structures for use in barrier packaging.

Laminated structures, for example mulif-layer films, are used to form various packagfrig articles including tubes, jars, cartons, pouches and the like. Laminated structures are particularly popular for forming tubes for oral care, for example toothpaste; cosmetics, for example mascara or p gloss; and OIY products, for example flUers and adhesives. These types of packaging may requfte certain barrier properties to control the ingress and egress of oxygen1 moisture, volatile oUs and/or aromas. The exact barrier properties required depend on the type of product stored in the packaging and the desired shelfilfe.

Conventionally, the types of barrier packaging described above are formed from a is laminated structure having a metal layer, for example an aLuminium foil layer, positioned between two layers of a poivolefin. The former of these ayers provides a moisture and an oxygen barrier whilst the latter provides a moisture barrier.

However, aluminium is expensive and is not suitable for use in many applications on account of its nontransparency.

US 3,347,419 describes a laminated collapsible dispensing tube having an intermediate layer of metal foil and an inner layer of thermoplastic forming an interior surface of the tube. The inner layer of thermoplastic is adhesively bonded to the foil layer by means of a suitable material that will prevent delamination of the layer through product attack. The outer surface of the foil layer is covered by a suitable layer for protection in handhng and for decoration purposes.

US 3172,571 describes a coilapsible dispensing tube having a thre&ply laminated body wall with inner and outer layers of a thermoplastic material and an intermediate s layer of preformed sheet materiaL for example thin metaHic foil or paper.

It is often desirable for the barrier packaging to be transparent so that the product within the packaging can be viewed prior to purchase. As a result, it has become increasingly popular to use a polyvinyl alcohol layer, ror example ethylene vinyl alcohol (EVOH), in place of the metal layer to provide transparent baffler packaging whilst maintaining the oxygen barrier properties.

US 3958721 describes a collapsible tube of synthetic re&n material adapted to prevent oxidisation of the substance contained therein. The body of the tube is constructed of a laminated sheet which compdses a polyethylene film, an oriented polypropylene film, a polyvinyl alcohol film and a polyethylene film, in the order 1.5 named.

However, there are several drawbacks to using a polyvinyl alcohol layer such as an EVOH layer. In particular, the oxygen barrier properties of EVOH are severely impaired by the presence of moisture. Thus thick polyolefin layers? typically greater than 120 pm, are required to cover the EVOH layer on both sides to h&p prevent the ingress of moisture. Thick polyolefin layers are also required to achieve the required stiffness for the packaging article since EVOH has a relatively low stiffness.

Thus, there is a need for an improved laminated structure for use in baffler packaging, which does not suffer from the disadvantages of the prior art. From the description that is to foflow, it wifi become apparent how the present invention addresses the deficiendes associated with the prior art constructions, whe presenfing numerous additional advantages not hitherto contemplated or possible

with the prior art constructions.

According to a first aspect of the present invention, there is provided a laminated structure for use in barrier packaging, the structure comprising a first layer providing oxygen barrier properties and at east one second layer providing moisture barrier oroperties, wherein the first layer has an oxygen permeabflity of no more than 5 cm3fm2/day and a tensile stiffness in the machine direction of greater than about 2800 MPa, and the second layer has a water vapour transmission rate of no more than 10 gIm2/day.

The oxygen permeabibty of the ffrst layer is measured according to ASTM Fl 927 at 23CC and 0% r&ative humidity. The first layer may have an oxygen permeabWty of no more than 4 cm3/m2/day, no more than 3 cm3lm2lday, no more than 2 cm3/m2/day, no more than 1 cm3/m2/day, no more than 0.5 cm3im2/day, no more than 0.3 cm3/m2/day or no more than 0.2 cm/m2/day when measured according to ASTM F1927 at 23°C and 0% relative humidity.

The oxygen permeabiUty of the first layer may vary depending on the r&ative humidity. For example, the oxygen permeabiUty of the first layer measured according to ASTM F1927 at 23°C and 50% relative humidity may be no more than 10 cm3/m2/day, no more than 8 cm3/m2/day, no more than S cm3/m2/day, or no more than 5 cm3/m2/day. The oxygen permeability of the first layer measured according to ASTM F1927 at 23°C and 70% relative humidity may be no more than 20 cm3/m2/day, no more than 15 cm3/m2/day, no more than 12 cm3/m2(day, or no more than 10 cm3/m2/day. The oxygen permeability of the first layer measured according S to ASTM F1927 at 23°C and 90% relative humidity may be no more than 30 cm3/m2/day, no more than 25 cm3/m2/day, no more than 20 cm3/m2/day, or no more than 18 cm3/m2/day.

The tensIle stiffness of the first layer is measured according to ASTM D882. The first layer may have a tensile stiffness in the machine direction of greater than about 2850 MPa, greater than about 2900 MPa, greater than about 2950 MPa, greater than about 3000 MPa, greater than about 3050 MPa or greater than about 3100 MPa. For example, the first layer may have a tensile stiffness in the machine direction of from about 2850 MPa to about 5000 MPa, from about 2900 MPa to about 4000 MPa, from about 2950 MPa to about 3500 MPa, from about 3000 MPa to about is 3400 MPa, or from about 3100 MPa to about 3300 MPa.

The first layer optionally has a tensile stiffness in the transverse direction of from about 1000 MPa to about 5000 MPa, from about 1100 MPa to about 4500 MPa, from about 1200 MPa to about 4000 MPa, from about 1300 MPa to about 3500 MPa, from about 1400 MPa to about 3000 MPa, or from about 1500 MPa to about 2500 MPa.

The tensile stiffness of the first layer In the machine direction and/or the transverse direction may be correlated to the flexural stiffness of the first layer In the machine and/or transverse direction. For example1 a high tensile stiffness of the first layer in the machine direction and/or the transverse direction may correlate to a high flexural stiffness of the first layer in the machine and/or transverse direction.

The water vapour transmission rate (WVTR) of the at least one second layer is measured according to ASTM E 96 at 384C and 90% relative humidity. The at least s one second layer may have a WVTR of no more than 9 g/m2/day, no more than 8 gIm2/day, no more than 7 g/m2lday, no more than 6 g/m2/day or no more than 5 g/m2/day when measured according to ASTM 98 at 38°C and 90% relative humidity.

Preferably, the WVTR of the at least one second layer is unaffected by the relative humidity.

The first layer of the laminated structure may be formed from a biodegradable and/or renewable material. This has the advantage that the laminated structure has increased biodegradability and/or a lower carbon footprint, particularly as compared to prior art constructions wherein the first layer is formed from a polyvinyl alcohol such as EVOH.

is The first layer may comprise cellulose and/or a cellulose derivative.

The cellulose may be cellulose regenerated from a cellulosic dispersion in a non-solvating fluid, for example N-methylmorpholine-N-oxide (MMMC) or a mixture of lithium chloride (LICI) and Dess-Martin perlodinane (DMP). One specific example is viscose' which is sodium cellulose xanthate in caustic soda. Cellulose from a dispersion can be cast into a film by regenerating the cellulose in situ by a suitable treatment, for example the addition of a suitable reagent (dilute sulphuric add for viscose), and optionay extruding the ceflubse thus formed. Such ceUulose is known herein as regenerated ceUulose.

The ceUulose derivative may be selected from ceflulose acetate, ceflulose diacetate and ceflulose triacetate.

s The thickness of the first layer arg&y depends upon the intended use of the aminaLed structure for use in barrier packaging. for example the barrier properties and/or stiffness required for the intended use, The first layer may have a thickness of from about 5 urn, from about 10 pm, from about 15 pm, from about 20 pm, from about 25 pm, from about 30 pm, from about 35 pm, from about 40 pm, from about 45 to pm or from about 50 pm; to about 55 pin, to about 60 pm, to about 65 pm, to about pm, to about 75 pm, to about 80 pm, to about 85 pm, to about 90 pm, to about 95 pm or to about 100 pm. In one embodiment, the first layer has a thickness of from about 10pm to about 60 pm.

Advantageou&y, the first layer has an increased tensile stiffness in the machine is direction, and optionaHy in the transverse direction, compared to that of an equivalent EVOH layer. For comparison, the tensile stiffness of an EVOH layer in the machine direction is from 2400 MPa to 2800 MPa, depending on the amount of ethylene present in the EVOH layer. Whereas the first layer of the laminated structure of the present invention has a tensUe stiffness in the machine direction of greater than about 2800 MPa, Consequently, the thickness of any or all of the layers in the laminated structure of the present invention may be downgauged compared to prior art constructions with an EVOH layer for example, whilst still maintaining the requisite stiffness for use In baffler packaging.

For example, where the laminated structure is used in baffler packaging in the form of a tube, the thickness of any or all of the layers in the laminated structure may be s down-gauged whilst still maintaining the requisite stiffness for the tube to be squeezed i.e. the haptic nature of the tube is maintained. Advantageously, the down-gauging of any or all of the layers in the laminated structure may result In a reduction in materials costs and hence a reduction in manufacturing costs of the tube.

Additionally, the first layer has good oxygen barrier properties which may be comparable to, and in some cases better than, those provided by an equivalent EVOH layer.

Where the first layer comprises cellulose and/or a cellulose derivative, an additional advantage may be realised, namely that the thickness of the at least one second layer may be down-gauged compared to prior art constructions with an EVOH layer is for example. The inventors of the present invention have surprisingly found that the oxygen barrier properties of a first layer comprising cellulose and/or a cellulose derivative are not Impaired by the presence of moisture to the same extent as an equivalent EVOH layer. Thus, the at least one second layer, which provides the moisture barrier, can be down-gauged. This may result in a reduction in the materials costs and hence the manufacturing costs of the laminated structure.

To improve certain properties of the laminated structure such as the moisture, oxygen, aroma and/or volatile oil baffler and/or the printability, one or both sides of the first layer may be coated wtth one or more coatings which may, for example, be applied from a solvent and/or aqueous dispersion. Suitable coatings include those comprising conventional nitrocellulose, vinyl chloride, vinyl acetate, acrylics, polyurethanes, polyesters, polyvinyl alcohols and/or any suitable mixtures or copolymers thereof.

The at least one second layer may comprise a thermoplastic material. More specificafly, the at least one second layer may comprise a thermoplastic material comprising polyethylene, polypropylene, polybutylene and/or compatible mixtures and/or blends thereof. Preferably, the at least one second layer comprises polyethylene. More preferably, the at least one second layer comprises linear low-density polyethylene (LLDPE). It is known that the above-mentioned thermoplastic materials have good moisture baffler properties.

The thermoplastic material may have a radio carbon content with a per cent modem carbon. Preferably, the thermoplastic material has a radio carbon content of at least is about I OpMC, or at least about 2OpMC, or at least about SOpMC, or at least about 4OpMC, or at least about 5OpMC, or at least about 6OpMC, or at least about 7OpMC, or at least about 8OpMC, or at least about 9OpMC, or at least about IOOpMC.

pMC' in this connection means per cent modem carbon'.

A radio carbon content with a per cent modem carbon indicates that the thermoplastic material, at least in part, is formed from a renewable source. One advantage of using at least one second layer which comprises a thermoplastic material having a radio carbon content with a relatively high per cent modem carbon is that the laminated structure has an increased renewability and a lower carbon footprint.

The at least one second layer may be a sealable layer. Preferably, the at least one second layer is heat sealable. By this, we mean that when heat is applied to the at s least one second layer it is activated to seal to another surface, for example another surface of the laminated structure.

The thickness of the at least one second layer largely depends on the intended use of the laminated structure for use in baffler packaging, for example the barrier properties and/or stiffness required for the intended use.

As previously mentioned, an advantage of the present invention is that the first layer has an increased tensile stiffness in the machine direction, and optionafly in the transverse direction, compared to an equivalent EVOH layer. Thus, the thickness of the at least one second layer can be down-gauged without reducing the overall stiffness of the laminated structure. This may have the benefit of reducing materials is costs and hence manufacturing costs of the laminated structure.

In addition, where the first layer comprises cellulose and/or a cellulose derivative, the oxygen baffler properties are not impaired by the presence of moisture to the same extent as an equivalent EVOH layer. Thus, the at least one second layer, which provides a moisture baffler, may be down-gauged further without substantially Impairing the oxygen baffler properties of the laminated structure.

The at least one second layer may have a thickness of about 125 pm or less, about pm or less, about 115 pm or less, about 110 pm or iCSS, about 105 pm or less, about 100 pm or less, about 95 pm or less, about 90 pm or less, about 85 pm or less or about 80 pm or less. Preferably, the at east one second layer has a thickness of s from about 80 pm to about 120 pm. More preferably, the at east one second layer has a thickness of from about 90 pm to about 115 pm. Most preferably, the at least one second layer has a thickness of from about 100 pm to about 110 pm.

The first and/or second layer may be at least in part formed from a reclaimed material i.e. a waste materiaL For example, the first and/or second layer may be at least in part formed from postconsumer reclaim material, Where the first and/or second layer is at least in part formed from a reclaimed material, one or more additional ayers of non-reclaimed material may be present in the laminated structure to prevent the layer(s) comprising reclaimed rnaleriai from coming into contact with an intended product in the barrier packaging.

The laminated structure may comprise vo second layers as described above.

Preferably, a second layer is positioned on either side of the first layer, such that the first layer is not exposed. in this laminated structure, the first layer may he considered a core layer.

Advantageously, the laminated structure of the present invention has excellent barrier properbes with regards to the ingress/egress of oxygen, moisture, volatile oils and aromas.

The laminated structure may comprise one or more additional ayers selected from: Ue layers, primer layers, printable layers. ink layers, lacquer layers, metal ayers and metaflised ayers, for example.

The laminated structure may comprise one or more tie layers to increase the degree S of adherence between the first layer and the at east one second layer. Preferably, a Ue layer is posifloned between the first layer and the at east one second layer.

The composition of the tie layer(s) larg&y depends on its compatibility with the material of the first layer and the material of the at least one second ayer. The compatibiUty of the tie layer may deter delamination of the at least one second layer iO from the first layer of the laminated structure. By 4compatibihty is preferably meant that the tie layer has an affinity, for example a chemical affinfty, both for the material of the at least one second layer and for the material of the first layer. The or each tie layer may be formed from a polymeric resin. The polymeric resin may comprise a polyolefin, for example, polyethylene, polypropylene, polybutylene and/or compatible is mixtures and/or blends thereof. The polyolefin may be modified, for example by substituting maleic anhydride groups onto the polymer backbone.

The or each tie layer may have a thickness in the range of from about 0.5 pm to about 50 pm. Preferably, the or each tie layer has a thickness in the range of from about 1 pm to about 20 pm, from about 1 pm to about 10 pm or from about 1 pm to about 5 pm.

The laminated structure may include a metallised layer. The metalUsed layer may be an additional layer in the laminated structure or it may form a part of the first and/or 11.

second layer. Preferably, the metallised layer forms a part of the first and/or second layer of the laminated structure. Where a metallised layer is used, particularly when it forms a part of the first and/or second layer, the barrier properties of the laminated structure may be improved without the need for an expensive metal layer, for S example an aluminium foil layer.

The laminated structure of the present invention may be transparent, translucent or opaque as desired. The laminated structure may be a multi-layer film.

The laminated structure may comprise any number of layers, for example from 2 to layers, or from 3 to 15 layers, or from 5 to 10 layers.

In one embodiment, the laminated structure comprises a first layer with a tie layer on either side thereof and a second layer positioned on the exposed surface of each of the tie layers, thus forming a 5-layer laminated structure.

In another embodiment, the laminated structure comprises a first layer with a tie layer on either side thereof and a second layer comprising a reclaimed material is positioned on the exposed surface of each of the tie layers. An additional layer of non-reclaimed material is positioned on the exposed surface of one of the second layers, thus forming a 8-layer laminated structure. When the laminated structure of this embodiment is used in baffler packaging, It Is preferably arranged such that the additional layer of non-reclaimed material forms an Inner surface of the baffler packaging i.e. preventing the layer of reclaimed material from coming Into contact with an intended product in the barrier packaging.

The laminated structure is for use in baffler packaging. The barrier packaging may be a tube-shaped container (simply a tube).

According to a second aspect of the present invention, there is provided a process for forming a laminated structure for use in baffler packaging, comprising extruding, s co-extruding or laminating a first layer providing oxygen baffler properties with at least one second layer providing moisture barrier properties, wherein the first layer has an oxygen permeability of no more than 5 cm3/m2/day and a tensile stiffness in the machine direction of greater than about 2800 MPa, and the second layer has a water vapour transmission rate of no more than 10 glrn2/day.

According to a third aspect of the present invention, there is provided a process for forming a tube-shaped baffler packaging from the laminated structure according to the first aspect of the present Invention, comprising the steps of: a) forming the laminated structure into an open-ended, hollow cylinder with an overlap region: b) heat sealing the laminated structure to itself in the overlap region; and c) inserting a head piece Into one of the open ends of the hollow cylinder and sealing It thereto.

The head piece may comprise a nozzle and/or a cap, for example.

The process may additionally comprise the step of filling the hollow cylinder with a product via the remaining open end and subsequently heat sealing the remaining open end of the laminated structure to itself.

For the avoidance of doubt, all features relating to the first aspect of the present Invention also relate to the second and third aspects of the present invention and vice versa.

The Invention will now be more particularly described with reference to the following, s non-limiting figures and examples.

Figure 1: a schematic diagram of a 5-layer laminated structure for use in barrier packaging Figure 2: a schematic diagram of a 7-layer laminated structure for use in barrier packaging Figure 3: a schematic diagram of a 6-layer laminated structure for use in barrier packaging Figure 1 shows a 5-layer laminated structure for use in baffler packaging, according to the present invention. A first layer I formed from cellulose and having a thickness of 15 pm is situated between two tie layers 2. The cellulose layer has an oxygen permeability of no more than 5 cm3/m2/day at 23°C and 0% relative humidity, and a tensile stiffness in the machine direction of approximately 3200 MPa. The tie layers 2 are formed from modified linear low-density polyethylene substituted with maleic anhydride groups, and each have a thickness of 5 pm. The 5-layer laminated structure also includes two second layers 3 positioned on the outer surface of the tie zo layers 2. The second layers 3 are heat sealable layers formed from linear low-density polyethylene, having a thickness of 115 pm and a water vapour transmission rate of no more than 10 g/m2/day at 38°C and 90% relative humidity. The tie layers 2 are compatible with both the cellulosic first layer I and the linear low-density polyethylene second layers 3, thus increasing the adherence between these layers.

The 5-layer laminated structure is transparent.

Sv Figure 2 shows a 7-layer laminated structure with the same basic structure as shown in Figure 1. with the addition of an ink layer 4 and a lacquer layerS. The ink layer 4 is directly printed onto one of the second layers 3. . A lacquer layer 5 is positioned over the ink layer 4 to provide protection to the ink layer. The lacquer layer 5 forms an outermost surface of the 7-layer laminated structure. The 7-layer laminated structure is transparent.

Figure 3 shows a 6-layer laminated structure for use In barrier packaging in accordance with the present invention. The first layer I and tie layers 2 have the same composition and thickness as in Figure 1. Two second layers 6 are positioned on the outer surface of the tie layers 2. The second layers 6 are heat sealable layers is formed from reclaimed linear low-density polyethylene. An additional layer of non-reclaimed linear low-density polyethylene 7 is positioned on the exposed surface of one of the second layers 6.

Where such a 6-layer laminated structure is used as baffler packaging, It is preferably arranged such that the additional layer of non-reclaimed material 7 forms an Inner surface of the barrier packaging.

Examples

Example I

The film samples outhned in Table I were tested for their votiIe oil barrier properties. Each of the film samples comprised a ceHulose layer wfth the thickness shown.

Table I

Sample Film Type Thickness I 430NK 30 2 33SNVS 23 4 440X8 31 430NE 30 Samples of virgin cardboard were spiked with 3 ml of paraffinic mineral oil (paraffin oil). The ofl was left to soak into the cardboard over a period of an hour (longer if required) so that the cardboard was not wet to touch. The cardboard was then 1.0 placed in contact with the film sample. A larger circular disc of filtration paper was placed underneath the film sample to trap any oil which transferred through the film sample. A weight was placed on top of the assembly to ensure good contact was made between the cardboard, film sample and fiftration paper, at all times. The assembly was left at room temperature for one week and after this the filtration paper as was removed for analysis and a new filtration paper inserted under the fflm sample.

This was repeated for a total of $ one week periods.

Each piece of filtration paper was placed in a conical flask, extracted with 50 ml of pentane, sonicated for 10 mInutes and allowed to stand for 12 hours. The filtration paper was then removed from the flask and the total volume reduced to 5 ml before vialing. The sample was analysed using gas chromatography in combination with a flame ionisation detector (GC-FID). The results are shown in Table 2.

Table 2

Paraffin Oil (ppm) Sample -______ _______ _______ _______ _______ _______ Week 1 Week 2 Week 3 Week 4 Week S Week 6

I ND ND ND ND ND ND

2 ND NE) ND ND ND_J_ND ND -not detected', less than limIt of detection 20 ppm mineral oil A similar experiment to that outlined above was carried out. The only difference being that the assembly was placed In an oven at 80°C rather than being left at room temperature during each one week period. The GC-FID results from this experiment are shown in Table 3.

is Table 3

Paraffin Oil (ppm) Sample -_____ ________ _____-_______ Weeki Week2.Week3 Week4 WeekS Week6

I ND ND ND ND ND ND

2 ND ND ND ND ND ND 3 ND ND ND ND ND ND 4 ND ND ND NDND ND

ND ND ND ND ND ND

ND -not detected', less than limit of detectIon 20 ppm mineral oil From the results it can be seen that all of the films tested act as good bafflers to the transmission of volatile paraffin oH at room temperature and at 60°C.

The results from the experiments carrIed out at 60°C suggest that the films tested will act as a baffler to paraffin oil for at least 3.5 years. This hypothesis is based on the model (Arrhenius Equation) used by Dr Koni Grob at the Food Safety Laboratory of the Canton of Zurich, Switzerland.

Example 2

A film comprising a white cellulose core layer was tested for its baffler properties against the transmission oF the aromas, menthol and phenyl ether.

The aroma barrier performance of the film was tested using GC-FID in combination with an experimental diffuser of gaseous aroma reagents (EDGAR) sampling is apparatus and switching value.

The results from the aroma barrier test are shown in Table 4.

Table 4

Area Response (my) Time (hours) Menthol Phenyl Ether 00:00:00 0 -0 03:32:00 0 0 19:06:00 0 0 20:51:00 0 0 23:49:00 0 0 25:59:00 0 -0 89:58:00 0 0 92:15:00 0 0 95:45:00 0 0 98:51:00 0 0 114:18:00 0 0 From the results it can be seen that there was no menthol or phenyl ether detected by the OC-FID In over 114 hours (nominally 5 days). Thus, the film has good aroma barrier propertIes. fl..

Claims

CLAIMS1. A aminated structure for use in barrier packaging, the structure comprising a first layer providing oxygen barher properties and at east one second layer providing moisture barrier properties, wherein the first ayer has an oxygen permeabifity of no more than 5 cm3/rn2fday and a tensile stiffness in the machine direction of greater than 2800 MPa, and the second ayer has a water vapour transmission rate of no more than 10 g/m2/day.
2. A laminated structure according to C'aim 1, wherein the first ayer has an oxygen permeability of no more than 4 crn3Im2/day, no more than 3 cm3/m2/day, no more than 2 crn3!m2/day, no more than 1 cm3/m2/day, no more than 0.5 cni3/m2/day, no more than 0.3 cm3/m2/day or no more than 0.2 cm3/m2/day when measured according to ASTM F1927 at 23°C and 0% r&ative humidity, from about 2850 MPa to about 5000 MPa, from about 2900 MPa to about 4000 MPa, from about 2950 MPa to about 3500 MPa, from about 3000 MPa to about 3400 MPa. or from about 3100 MPa to about 3300 MPa
3. A aminated structure according to Claim I or Ciaim 2, wherein the first layer has a stiffness of: a. from about 2850 MPa to about 5000 MPa; b. from about 2900 MPa to about 4000 MFa; c. from about 2950 MPa to about 3500 MPa; d. from about 3000 MPa to about 3400 MPa; or e. from about 3100 PAPa to about 3300 MPa.
4. A laminated structure according to any one of claims 1 to 3, wherein the at least one second layer has a water vapour transmission rate of no more than 9 g/m2iday, no more than 8 g/m2/day, no more than 7 g/m2/day, no more than 6 g/m2/day or no more than 5 g/m2/day when measured according to ASTM 96 at 38°C and 90% relative humidity.
5. A laminated structure according to any one of claims I to 4, wherein the first layer is formed from a biodegradable and/or renewable material.
6. A laminated structure according to any one of claims 1 to 5, wherein the first layer comprises cellulose and/or a cellulose derivative, optionally wherein the first layer comprises regenerated cellulose.
7. A laminated structure according to any one of claims I to 6, wherein the at least one second layer comprises a thermoplastic material
8. A laminated structure according to Claim 7, whereIn the thermoplastic material comprises polyethylene, polypropylene, polybutylene and/or compatible mixtures and/or blends thereof. fl9. A laminated structure according to Claim 8, whereIn the thermoplastic material comprises polyethylene, optionally linear low-density polyethylene.I 0.A laminated structure according to any one of claims 7 to 9, wherein the thermoplastic material has a radio carbon content with a per cent modem carbon.11.A laminated structure according to Claim 10, wherein the thermoplastic material has a radio carbon content of at least about I OpMC, or at least about 2OpMC, or at least about 3OpMC, or at least about 4OpMC, or at least about 5OpMC, or at least about 6OpMC, or at least about 7OpMC, or at least about 8OpMC, or at least about 9OpMC, or at least about IOOpMC.12.A laminated structure according to any one of claims I to ii, wherein the at least one second layer is a sealable layer, optionally a heat sealable layer.13.A laminated structure according to any one of claims 1 to 12, wherein the at least one second layer has a thickness in the range of: a. from about 80 pm to about 120 pm; b. from about 90 pm to about 115 pm; or c. from about 100 pm to about 110 pm.14.A laminated structure according to any one of claims ito 13, wherein the first and/or second layer is at least In part formed from a reclaimed material.16.A laminated structure according to any one of claims I to 14, further comprising one or more tie layers.16.A laminated structure according to Claim 15, wherein the tie layer is positioned between the first layer and the at least one second layer.17.A laminated structure according to Claim 15 or Claim 16, wherein the or each tie layer comprises a polymeric resin comprising a polyolefin selected from polyethylene, polypropylene, polybutylene and/or compatible mixtures and/or blends thereof, optionally wherein the polyolefin is modified by substituting maleic anhydride groups onto the polymer backbone.18.A laminated structure according to any one of claims 15 to 17. wherein the or each tie layer has a thickness of from: a. about 0.6 pm to about 50 pm; b. from about 1 pm to about 20 pm; c. from about 1 pm to about 10 pm; or d. from about 1 pm to about 5 pm.19.A laminated structure according to any one of claims I to 18, comprising a first layer with a tie layer on either side thereof and a second layer positioned on the exposed surface of each of the tie layers. a20.A laminated structure according to any one of claims I to 19 further comprising one or more addftion& layers selected from: tie layers, primer layers, printable layers, ink layers, lacquer layers, metal layers and metaHised ayers 21.A laminated structure according to Claim 20, compri&ng an ink layer dfrectly printed onto the at least one second layer.22.A laminated structure according to Claim 21, comprising a lacquer layer posifloned over the ink layer.23.A laminated structure according to any one of claims I to 22, wher&n the structure is transparent, tran&ucent or opaque.24.A laminated structure for use in barrier packaging according to any one of claims Ito 23, wherein the barrier packaging is a tube-shaped container.25A process for forming a laminated structure for use in barrier packaging, comprising extruding, coextruding or laminating a first layer providing oxygen barrier properties with at east one second layer providing moisture barrier properties, wherein the first layer has an oxygen permeability of no more than cm3/m4/day and a tense stiffness in the machine direction of greater than about 2OO MPa, and the second layer has a water vapour transmission rate of no more than 10 g/m2/day.26.A process for forming a tube-shaped barrier packaging, comprising the steps of: a. forming a laminated structure according to any one of claims I to 24 into an open-ended, hollow cylinder with an overlap region: b. heat sealing the laminated structure to itself in the overlap region; and c. inserting a head piece into one of the open ends of the holiow cylinder and sealing it thereto.27.A process according to Claim 26, additionally comprising the step of filling the hollow cylinder with a product via the remaining open end of the hollow cylinder.28.A process according to Claim 27, additionally comprising the step of heat sealing the remaining open end of the hollow cylinder.